[PATCH v10 00/14] btrfs: add ioctls and send/receive support for reading/writing compressed data

[PATCH v10 00/14] btrfs: add ioctls and send/receive support for reading/writing compressed data

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

This series has three parts: new Btrfs ioctls for reading/writing
compressed data, support for sending compressed data via Btrfs send, and
btrfs-progs support for sending/receiving compressed data and writing it
with the new ioctl.

The Btrfs ioctls for reading compressed data from a file without
decompressing it and for writing compressed data directly to a file are
adapted from my previous attempt to do this as an extension to
preadv2/pwritev2 [1]. We weren't able to come up with a generic
interface that everyone was happy with, so we're going to do this
ourselves in Btrfs. If another user comes along, we can generalize it
then. Test cases are here [2]

Patches 1 and 2 are VFS changes exporting a couple of helpers for checks
needed by reads and writes. Patches 3-7 are preparatory Btrfs changes
for compressed reads and writes. Patch 8 adds the compressed read ioctl
and patch 9 adds the compressed write ioctl.

The main use-case for this interface is Btrfs send/receive. Currently,
when sending data from one compressed filesystem to another, the sending
side decompresses the data and the receiving side recompresses it before
writing it out. This is wasteful and can be avoided if we can just send
and write compressed extents.

Patches 10-14 add the Btrfs send support. See the previous posting for
more details and benchmarks [3]. Patches 10-12 prepare some protocol
changes for send stream v2. Patch 13 implements compressed send. Patch
14 enables send stream v2 and compressed send in the send ioctl when
requested.

These patches are based on Dave Sterba's Btrfs misc-next branch [4],
which is in turn currently based on v5.14-rc6.

1: https://lore.kernel.org/linux-fsdevel/cover.1623972518.git.osandov@fb.com/
2: https://github.com/osandov/xfstests/tree/btrfs-encoded-io
3: https://lore.kernel.org/linux-btrfs/cover.1615922753.git.osandov@fb.com/
4: https://github.com/kdave/btrfs-devel/tree/misc-next

Omar Sandoval (14):
  fs: export rw_verify_area()
  fs: export variant of generic_write_checks without iov_iter
  btrfs: don't advance offset for compressed bios in
    btrfs_csum_one_bio()
  btrfs: add ram_bytes and offset to btrfs_ordered_extent
  btrfs: support different disk extent size for delalloc
  btrfs: optionally extend i_size in cow_file_range_inline()
  btrfs: add definitions + documentation for encoded I/O ioctls
  btrfs: add BTRFS_IOC_ENCODED_READ
  btrfs: add BTRFS_IOC_ENCODED_WRITE
  btrfs: add send stream v2 definitions
  btrfs: send: write larger chunks when using stream v2
  btrfs: send: allocate send buffer with alloc_page() and vmap() for v2
  btrfs: send: send compressed extents with encoded writes
  btrfs: send: enable support for stream v2 and compressed writes

 fs/btrfs/compression.c     |  12 +-
 fs/btrfs/compression.h     |   6 +-
 fs/btrfs/ctree.h           |  17 +-
 fs/btrfs/delalloc-space.c  |  18 +-
 fs/btrfs/file-item.c       |  35 +-
 fs/btrfs/file.c            |  68 ++-
 fs/btrfs/inode.c           | 911 +++++++++++++++++++++++++++++++++----
 fs/btrfs/ioctl.c           | 213 +++++++++
 fs/btrfs/ordered-data.c    | 124 ++---
 fs/btrfs/ordered-data.h    |  25 +-
 fs/btrfs/relocation.c      |   2 +-
 fs/btrfs/send.c            | 307 +++++++++++--
 fs/btrfs/send.h            |  32 +-
 fs/internal.h              |   5 -
 fs/read_write.c            |  41 +-
 include/linux/fs.h         |   2 +
 include/uapi/linux/btrfs.h | 149 +++++-
 17 files changed, 1690 insertions(+), 277 deletions(-)

The btrfs-progs patches were written by Boris Burkov with some updates
from me. Patches 1-4 are preparation. Patch 5 implements encoded writes.
Patch 6 implements the fallback to decompressing. Patches 7 and 8
implement the other commands. Patch 9 adds the new `btrfs send` options.
Patch 10 adds a test case.

Boris Burkov (10):
  btrfs-progs: receive: support v2 send stream larger tlv_len
  btrfs-progs: receive: dynamically allocate sctx->read_buf
  btrfs-progs: receive: support v2 send stream DATA tlv format
  btrfs-progs: receive: add send stream v2 cmds and attrs to send.h
  btrfs-progs: receive: process encoded_write commands
  btrfs-progs: receive: encoded_write fallback to explicit decode and
    write
  btrfs-progs: receive: process fallocate commands
  btrfs-progs: receive: process setflags ioctl commands
  btrfs-progs: send: stream v2 ioctl flags
  btrfs-progs: receive: add tests for basic encoded_write send/receive

 Documentation/btrfs-receive.asciidoc          |   4 +
 Documentation/btrfs-send.asciidoc             |  16 +-
 cmds/receive-dump.c                           |  31 +-
 cmds/receive.c                                | 347 +++++++++++++++++-
 cmds/send.c                                   |  54 ++-
 common/send-stream.c                          | 157 ++++++--
 common/send-stream.h                          |   7 +
 ioctl.h                                       | 149 +++++++-
 libbtrfsutil/btrfs.h                          |  17 +-
 send.h                                        |  19 +-
 .../049-receive-write-encoded/test.sh         | 114 ++++++
 11 files changed, 871 insertions(+), 44 deletions(-)
 create mode 100755 tests/misc-tests/049-receive-write-encoded/test.sh

-- 
2.32.0

[PATCH v10 01/14] fs: export rw_verify_area()

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

I'm adding Btrfs ioctls to read and write compressed data, and rather
than duplicating the checks in rw_verify_area(), let's just export it.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 fs/internal.h      | 5 -----
 fs/read_write.c    | 1 +
 include/linux/fs.h | 1 +
 3 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index 82e8eb32ff3d..f471894d87d4 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -165,11 +165,6 @@ extern char *simple_dname(struct dentry *, char *, int);
 extern void dput_to_list(struct dentry *, struct list_head *);
 extern void shrink_dentry_list(struct list_head *);
 
-/*
- * read_write.c
- */
-extern int rw_verify_area(int, struct file *, const loff_t *, size_t);
-
 /*
  * pipe.c
  */
diff --git a/fs/read_write.c b/fs/read_write.c
index 9db7adf160d2..0029ff2b0ca8 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -400,6 +400,7 @@ int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t
 	return security_file_permission(file,
 				read_write == READ ? MAY_READ : MAY_WRITE);
 }
+EXPORT_SYMBOL(rw_verify_area);
 
 static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
 {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1751addcb36e..0de4d75339b9 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3274,6 +3274,7 @@ extern loff_t fixed_size_llseek(struct file *file, loff_t offset,
 		int whence, loff_t size);
 extern loff_t no_seek_end_llseek_size(struct file *, loff_t, int, loff_t);
 extern loff_t no_seek_end_llseek(struct file *, loff_t, int);
+extern int rw_verify_area(int, struct file *, const loff_t *, size_t);
 extern int generic_file_open(struct inode * inode, struct file * filp);
 extern int nonseekable_open(struct inode * inode, struct file * filp);
 extern int stream_open(struct inode * inode, struct file * filp);
-- 
2.32.0

[PATCH v10 02/14] fs: export variant of generic_write_checks without iov_iter

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

Encoded I/O in Btrfs needs to check a write with a given logical size
without an iov_iter that matches that size (because the iov_iter we have
is for the compressed data). So, factor out the parts of
generic_write_check() that expect an iov_iter into a new
__generic_write_checks() function and export that.

Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 fs/read_write.c    | 40 ++++++++++++++++++++++------------------
 include/linux/fs.h |  1 +
 2 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index 0029ff2b0ca8..3bddd5ee7f64 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1633,6 +1633,26 @@ int generic_write_check_limits(struct file *file, loff_t pos, loff_t *count)
 	return 0;
 }
 
+/* Like generic_write_checks(), but takes size of write instead of iter. */
+int __generic_write_checks(struct kiocb *iocb, loff_t *count)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file->f_mapping->host;
+
+	if (IS_SWAPFILE(inode))
+		return -ETXTBSY;
+
+	/* FIXME: this is for backwards compatibility with 2.4 */
+	if (iocb->ki_flags & IOCB_APPEND)
+		iocb->ki_pos = i_size_read(inode);
+
+	if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
+		return -EINVAL;
+
+	return generic_write_check_limits(iocb->ki_filp, iocb->ki_pos, count);
+}
+EXPORT_SYMBOL(__generic_write_checks);
+
 /*
  * Performs necessary checks before doing a write
  *
@@ -1642,26 +1662,10 @@ int generic_write_check_limits(struct file *file, loff_t pos, loff_t *count)
  */
 ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from)
 {
-	struct file *file = iocb->ki_filp;
-	struct inode *inode = file->f_mapping->host;
-	loff_t count;
+	loff_t count = iov_iter_count(from);
 	int ret;
 
-	if (IS_SWAPFILE(inode))
-		return -ETXTBSY;
-
-	if (!iov_iter_count(from))
-		return 0;
-
-	/* FIXME: this is for backwards compatibility with 2.4 */
-	if (iocb->ki_flags & IOCB_APPEND)
-		iocb->ki_pos = i_size_read(inode);
-
-	if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
-		return -EINVAL;
-
-	count = iov_iter_count(from);
-	ret = generic_write_check_limits(file, iocb->ki_pos, &count);
+	ret = __generic_write_checks(iocb, &count);
 	if (ret)
 		return ret;
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 0de4d75339b9..b206814da181 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3227,6 +3227,7 @@ extern int sb_min_blocksize(struct super_block *, int);
 extern int generic_file_mmap(struct file *, struct vm_area_struct *);
 extern int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);
 extern ssize_t generic_write_checks(struct kiocb *, struct iov_iter *);
+extern int __generic_write_checks(struct kiocb *iocb, loff_t *count);
 extern int generic_write_check_limits(struct file *file, loff_t pos,
 		loff_t *count);
 extern int generic_file_rw_checks(struct file *file_in, struct file *file_out);
-- 
2.32.0

[PATCH v10 03/14] btrfs: don't advance offset for compressed bios in btrfs_csum_one_bio()

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

btrfs_csum_one_bio() loops over each filesystem block in the bio while
keeping a cursor of its current logical position in the file in order to
look up the ordered extent to add the checksums to. However, this
doesn't make much sense for compressed extents, as a sector on disk does
not correspond to a sector of decompressed file data. It happens to work
because 1) the compressed bio always covers one ordered extent and 2)
the size of the bio is always less than the size of the ordered extent.
However, the second point will not always be true for encoded writes.

Let's add a boolean parameter to btrfs_csum_one_bio() to indicate that
it can assume that the bio only covers one ordered extent. Since we're
already changing the signature, let's get rid of the contig parameter
and make it implied by the offset parameter, similar to the change we
recently made to btrfs_lookup_bio_sums(). Additionally, let's rename
nr_sectors to blockcount to make it clear that it's the number of
filesystem blocks, not the number of 512-byte sectors.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 fs/btrfs/compression.c |  5 +++--
 fs/btrfs/ctree.h       |  2 +-
 fs/btrfs/file-item.c   | 35 ++++++++++++++++-------------------
 fs/btrfs/inode.c       |  8 ++++----
 4 files changed, 24 insertions(+), 26 deletions(-)

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 7869ad12bc6e..e645b3c2f09a 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -480,7 +480,8 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
 			BUG_ON(ret); /* -ENOMEM */
 
 			if (!skip_sum) {
-				ret = btrfs_csum_one_bio(inode, bio, start, 1);
+				ret = btrfs_csum_one_bio(inode, bio, start,
+							 true);
 				BUG_ON(ret); /* -ENOMEM */
 			}
 
@@ -516,7 +517,7 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
 	BUG_ON(ret); /* -ENOMEM */
 
 	if (!skip_sum) {
-		ret = btrfs_csum_one_bio(inode, bio, start, 1);
+		ret = btrfs_csum_one_bio(inode, bio, start, true);
 		BUG_ON(ret); /* -ENOMEM */
 	}
 
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index f07c82fafa04..be245b4b8efe 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3111,7 +3111,7 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
 			   struct btrfs_root *root,
 			   struct btrfs_ordered_sum *sums);
 blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
-				u64 file_start, int contig);
+				u64 offset, bool one_ordered);
 int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
 			     struct list_head *list, int search_commit);
 void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 2673c6ba7a4e..844fae923340 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -614,28 +614,28 @@ int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
  * btrfs_csum_one_bio - Calculates checksums of the data contained inside a bio
  * @inode:	 Owner of the data inside the bio
  * @bio:	 Contains the data to be checksummed
- * @file_start:  offset in file this bio begins to describe
- * @contig:	 Boolean. If true/1 means all bio vecs in this bio are
- *		 contiguous and they begin at @file_start in the file. False/0
- *		 means this bio can contain potentially discontiguous bio vecs
- *		 so the logical offset of each should be calculated separately.
+ * @offset:      If (u64)-1, @bio may contain discontiguous bio vecs, so the
+ *               file offsets are determined from the page offsets in the bio.
+ *               Otherwise, this is the starting file offset of the bio vecs in
+ *               @bio, which must be contiguous.
+ * @one_ordered: If true, @bio only refers to one ordered extent.
  */
 blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
-		       u64 file_start, int contig)
+				u64 offset, bool one_ordered)
 {
 	struct btrfs_fs_info *fs_info = inode->root->fs_info;
 	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
 	struct btrfs_ordered_sum *sums;
 	struct btrfs_ordered_extent *ordered = NULL;
+	const bool page_offsets = (offset == (u64)-1);
 	char *data;
 	struct bvec_iter iter;
 	struct bio_vec bvec;
 	int index;
-	int nr_sectors;
+	int blockcount;
 	unsigned long total_bytes = 0;
 	unsigned long this_sum_bytes = 0;
 	int i;
-	u64 offset;
 	unsigned nofs_flag;
 
 	nofs_flag = memalloc_nofs_save();
@@ -649,18 +649,13 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
 	sums->len = bio->bi_iter.bi_size;
 	INIT_LIST_HEAD(&sums->list);
 
-	if (contig)
-		offset = file_start;
-	else
-		offset = 0; /* shut up gcc */
-
 	sums->bytenr = bio->bi_iter.bi_sector << 9;
 	index = 0;
 
 	shash->tfm = fs_info->csum_shash;
 
 	bio_for_each_segment(bvec, bio, iter) {
-		if (!contig)
+		if (page_offsets)
 			offset = page_offset(bvec.bv_page) + bvec.bv_offset;
 
 		if (!ordered) {
@@ -668,13 +663,14 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
 			BUG_ON(!ordered); /* Logic error */
 		}
 
-		nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info,
+		blockcount = BTRFS_BYTES_TO_BLKS(fs_info,
 						 bvec.bv_len + fs_info->sectorsize
 						 - 1);
 
-		for (i = 0; i < nr_sectors; i++) {
-			if (offset >= ordered->file_offset + ordered->num_bytes ||
-			    offset < ordered->file_offset) {
+		for (i = 0; i < blockcount; i++) {
+			if (!one_ordered &&
+			    (offset >= ordered->file_offset + ordered->num_bytes ||
+			     offset < ordered->file_offset)) {
 				unsigned long bytes_left;
 
 				sums->len = this_sum_bytes;
@@ -705,7 +701,8 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
 					    sums->sums + index);
 			kunmap_atomic(data);
 			index += fs_info->csum_size;
-			offset += fs_info->sectorsize;
+			if (!one_ordered)
+				offset += fs_info->sectorsize;
 			this_sum_bytes += fs_info->sectorsize;
 			total_bytes += fs_info->sectorsize;
 		}
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 2aa9646bce56..abee704fc468 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2286,7 +2286,7 @@ int btrfs_bio_fits_in_stripe(struct page *page, size_t size, struct bio *bio,
 static blk_status_t btrfs_submit_bio_start(struct inode *inode, struct bio *bio,
 					   u64 dio_file_offset)
 {
-	return btrfs_csum_one_bio(BTRFS_I(inode), bio, 0, 0);
+	return btrfs_csum_one_bio(BTRFS_I(inode), bio, (u64)-1, false);
 }
 
 /*
@@ -2538,7 +2538,7 @@ blk_status_t btrfs_submit_data_bio(struct inode *inode, struct bio *bio,
 					  0, btrfs_submit_bio_start);
 		goto out;
 	} else if (!skip_sum) {
-		ret = btrfs_csum_one_bio(BTRFS_I(inode), bio, 0, 0);
+		ret = btrfs_csum_one_bio(BTRFS_I(inode), bio, (u64)-1, false);
 		if (ret)
 			goto out;
 	}
@@ -8136,7 +8136,7 @@ static blk_status_t btrfs_submit_bio_start_direct_io(struct inode *inode,
 						     struct bio *bio,
 						     u64 dio_file_offset)
 {
-	return btrfs_csum_one_bio(BTRFS_I(inode), bio, dio_file_offset, 1);
+	return btrfs_csum_one_bio(BTRFS_I(inode), bio, dio_file_offset, false);
 }
 
 static void btrfs_end_dio_bio(struct bio *bio)
@@ -8195,7 +8195,7 @@ static inline blk_status_t btrfs_submit_dio_bio(struct bio *bio,
 		 * If we aren't doing async submit, calculate the csum of the
 		 * bio now.
 		 */
-		ret = btrfs_csum_one_bio(BTRFS_I(inode), bio, file_offset, 1);
+		ret = btrfs_csum_one_bio(BTRFS_I(inode), bio, file_offset, false);
 		if (ret)
 			goto err;
 	} else {
-- 
2.32.0

[PATCH v10 04/14] btrfs: add ram_bytes and offset to btrfs_ordered_extent

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

Currently, we only create ordered extents when ram_bytes == num_bytes
and offset == 0. However, RWF_ENCODED writes may create extents which
only refer to a subset of the full unencoded extent, so we need to plumb
these fields through the ordered extent infrastructure and pass them
down to insert_reserved_file_extent().

Since we're changing the btrfs_add_ordered_extent* signature, let's get
rid of the trivial wrappers and add a kernel-doc.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 fs/btrfs/inode.c        |  56 +++++++++++---------
 fs/btrfs/ordered-data.c | 112 +++++++++++-----------------------------
 fs/btrfs/ordered-data.h |  22 ++++----
 3 files changed, 76 insertions(+), 114 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index abee704fc468..67db9d0a79ec 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -945,12 +945,12 @@ static noinline void submit_compressed_extents(struct async_chunk *async_chunk)
 			goto out_free_reserve;
 		free_extent_map(em);
 
-		ret = btrfs_add_ordered_extent_compress(inode,
-						async_extent->start,
-						ins.objectid,
-						async_extent->ram_size,
-						ins.offset,
-						async_extent->compress_type);
+		ret = btrfs_add_ordered_extent(inode, async_extent->start,
+					       async_extent->ram_size,
+					       async_extent->ram_size,
+					       ins.objectid, ins.offset, 0,
+					       1 << BTRFS_ORDERED_COMPRESSED,
+					       async_extent->compress_type);
 		if (ret) {
 			btrfs_drop_extent_cache(inode, async_extent->start,
 						async_extent->start +
@@ -1180,9 +1180,9 @@ static noinline int cow_file_range(struct btrfs_inode *inode,
 		}
 		free_extent_map(em);
 
-		ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
-					       ram_size, cur_alloc_size,
-					       BTRFS_ORDERED_REGULAR);
+		ret = btrfs_add_ordered_extent(inode, start, ram_size, ram_size,
+					       ins.objectid, cur_alloc_size, 0,
+					       0, BTRFS_COMPRESS_NONE);
 		if (ret)
 			goto out_drop_extent_cache;
 
@@ -1843,10 +1843,11 @@ static noinline int run_delalloc_nocow(struct btrfs_inode *inode,
 				goto error;
 			}
 			free_extent_map(em);
-			ret = btrfs_add_ordered_extent(inode, cur_offset,
-						       disk_bytenr, num_bytes,
-						       num_bytes,
-						       BTRFS_ORDERED_PREALLOC);
+			ret = btrfs_add_ordered_extent(inode,
+					cur_offset, num_bytes, num_bytes,
+					disk_bytenr, num_bytes, 0,
+					1 << BTRFS_ORDERED_PREALLOC,
+					BTRFS_COMPRESS_NONE);
 			if (ret) {
 				btrfs_drop_extent_cache(inode, cur_offset,
 							cur_offset + num_bytes - 1,
@@ -1855,9 +1856,11 @@ static noinline int run_delalloc_nocow(struct btrfs_inode *inode,
 			}
 		} else {
 			ret = btrfs_add_ordered_extent(inode, cur_offset,
+						       num_bytes, num_bytes,
 						       disk_bytenr, num_bytes,
-						       num_bytes,
-						       BTRFS_ORDERED_NOCOW);
+						       0,
+						       1 << BTRFS_ORDERED_NOCOW,
+						       BTRFS_COMPRESS_NONE);
 			if (ret)
 				goto error;
 		}
@@ -2842,6 +2845,7 @@ static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
 	struct btrfs_key ins;
 	u64 disk_num_bytes = btrfs_stack_file_extent_disk_num_bytes(stack_fi);
 	u64 disk_bytenr = btrfs_stack_file_extent_disk_bytenr(stack_fi);
+	u64 offset = btrfs_stack_file_extent_offset(stack_fi);
 	u64 num_bytes = btrfs_stack_file_extent_num_bytes(stack_fi);
 	u64 ram_bytes = btrfs_stack_file_extent_ram_bytes(stack_fi);
 	struct btrfs_drop_extents_args drop_args = { 0 };
@@ -2916,7 +2920,8 @@ static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
 		goto out;
 
 	ret = btrfs_alloc_reserved_file_extent(trans, root, btrfs_ino(inode),
-					       file_pos, qgroup_reserved, &ins);
+					       file_pos - offset,
+					       qgroup_reserved, &ins);
 out:
 	btrfs_free_path(path);
 
@@ -2942,20 +2947,20 @@ static int insert_ordered_extent_file_extent(struct btrfs_trans_handle *trans,
 					     struct btrfs_ordered_extent *oe)
 {
 	struct btrfs_file_extent_item stack_fi;
-	u64 logical_len;
 	bool update_inode_bytes;
+	u64 num_bytes = oe->num_bytes;
+	u64 ram_bytes = oe->ram_bytes;
 
 	memset(&stack_fi, 0, sizeof(stack_fi));
 	btrfs_set_stack_file_extent_type(&stack_fi, BTRFS_FILE_EXTENT_REG);
 	btrfs_set_stack_file_extent_disk_bytenr(&stack_fi, oe->disk_bytenr);
 	btrfs_set_stack_file_extent_disk_num_bytes(&stack_fi,
 						   oe->disk_num_bytes);
+	btrfs_set_stack_file_extent_offset(&stack_fi, oe->offset);
 	if (test_bit(BTRFS_ORDERED_TRUNCATED, &oe->flags))
-		logical_len = oe->truncated_len;
-	else
-		logical_len = oe->num_bytes;
-	btrfs_set_stack_file_extent_num_bytes(&stack_fi, logical_len);
-	btrfs_set_stack_file_extent_ram_bytes(&stack_fi, logical_len);
+		num_bytes = ram_bytes = oe->truncated_len;
+	btrfs_set_stack_file_extent_num_bytes(&stack_fi, num_bytes);
+	btrfs_set_stack_file_extent_ram_bytes(&stack_fi, ram_bytes);
 	btrfs_set_stack_file_extent_compression(&stack_fi, oe->compress_type);
 	/* Encryption and other encoding is reserved and all 0 */
 
@@ -7391,8 +7396,11 @@ static struct extent_map *btrfs_create_dio_extent(struct btrfs_inode *inode,
 		if (IS_ERR(em))
 			goto out;
 	}
-	ret = btrfs_add_ordered_extent_dio(inode, start, block_start, len,
-					   block_len, type);
+	ret = btrfs_add_ordered_extent(inode, start, len, len, block_start,
+				       block_len, 0,
+				       (1 << type) |
+				       (1 << BTRFS_ORDERED_DIRECT),
+				       BTRFS_COMPRESS_NONE);
 	if (ret) {
 		if (em) {
 			free_extent_map(em);
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index edb65abf0393..550c34fa0e6d 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -143,16 +143,27 @@ static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
 	return ret;
 }
 
-/*
- * Allocate and add a new ordered_extent into the per-inode tree.
+/**
+ * btrfs_add_ordered_extent - Add an ordered extent to the per-inode tree.
+ * @inode: inode that this extent is for.
+ * @file_offset: Logical offset in file where the extent starts.
+ * @num_bytes: Logical length of extent in file.
+ * @ram_bytes: Full length of unencoded data.
+ * @disk_bytenr: Offset of extent on disk.
+ * @disk_num_bytes: Size of extent on disk.
+ * @offset: Offset into unencoded data where file data starts.
+ * @flags: Flags specifying type of extent (1 << BTRFS_ORDERED_*).
+ * @compress_type: Compression algorithm used for data.
  *
- * The tree is given a single reference on the ordered extent that was
- * inserted.
+ * Most of these parameters correspond to &struct btrfs_file_extent_item. The
+ * tree is given a single reference on the ordered extent that was inserted.
+ *
+ * Return: 0 or -ENOMEM.
  */
-static int __btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset,
-				      u64 disk_bytenr, u64 num_bytes,
-				      u64 disk_num_bytes, int type, int dio,
-				      int compress_type)
+int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset,
+			     u64 num_bytes, u64 ram_bytes, u64 disk_bytenr,
+			     u64 disk_num_bytes, u64 offset, int flags,
+			     int compress_type)
 {
 	struct btrfs_root *root = inode->root;
 	struct btrfs_fs_info *fs_info = root->fs_info;
@@ -161,7 +172,8 @@ static int __btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset
 	struct btrfs_ordered_extent *entry;
 	int ret;
 
-	if (type == BTRFS_ORDERED_NOCOW || type == BTRFS_ORDERED_PREALLOC) {
+	if (flags &
+	    ((1 << BTRFS_ORDERED_NOCOW) | (1 << BTRFS_ORDERED_PREALLOC))) {
 		/* For nocow write, we can release the qgroup rsv right now */
 		ret = btrfs_qgroup_free_data(inode, NULL, file_offset, num_bytes);
 		if (ret < 0)
@@ -181,9 +193,11 @@ static int __btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset
 		return -ENOMEM;
 
 	entry->file_offset = file_offset;
-	entry->disk_bytenr = disk_bytenr;
 	entry->num_bytes = num_bytes;
+	entry->ram_bytes = ram_bytes;
+	entry->disk_bytenr = disk_bytenr;
 	entry->disk_num_bytes = disk_num_bytes;
+	entry->offset = offset;
 	entry->bytes_left = num_bytes;
 	entry->inode = igrab(&inode->vfs_inode);
 	entry->compress_type = compress_type;
@@ -191,18 +205,12 @@ static int __btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset
 	entry->qgroup_rsv = ret;
 	entry->physical = (u64)-1;
 
-	ASSERT(type == BTRFS_ORDERED_REGULAR ||
-	       type == BTRFS_ORDERED_NOCOW ||
-	       type == BTRFS_ORDERED_PREALLOC ||
-	       type == BTRFS_ORDERED_COMPRESSED);
-	set_bit(type, &entry->flags);
+	ASSERT((flags & ~BTRFS_ORDERED_TYPE_FLAGS) == 0);
+	entry->flags = flags;
 
 	percpu_counter_add_batch(&fs_info->ordered_bytes, num_bytes,
 				 fs_info->delalloc_batch);
 
-	if (dio)
-		set_bit(BTRFS_ORDERED_DIRECT, &entry->flags);
-
 	/* one ref for the tree */
 	refcount_set(&entry->refs, 1);
 	init_waitqueue_head(&entry->wait);
@@ -247,41 +255,6 @@ static int __btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset
 	return 0;
 }
 
-int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset,
-			     u64 disk_bytenr, u64 num_bytes, u64 disk_num_bytes,
-			     int type)
-{
-	ASSERT(type == BTRFS_ORDERED_REGULAR ||
-	       type == BTRFS_ORDERED_NOCOW ||
-	       type == BTRFS_ORDERED_PREALLOC);
-	return __btrfs_add_ordered_extent(inode, file_offset, disk_bytenr,
-					  num_bytes, disk_num_bytes, type, 0,
-					  BTRFS_COMPRESS_NONE);
-}
-
-int btrfs_add_ordered_extent_dio(struct btrfs_inode *inode, u64 file_offset,
-				 u64 disk_bytenr, u64 num_bytes,
-				 u64 disk_num_bytes, int type)
-{
-	ASSERT(type == BTRFS_ORDERED_REGULAR ||
-	       type == BTRFS_ORDERED_NOCOW ||
-	       type == BTRFS_ORDERED_PREALLOC);
-	return __btrfs_add_ordered_extent(inode, file_offset, disk_bytenr,
-					  num_bytes, disk_num_bytes, type, 1,
-					  BTRFS_COMPRESS_NONE);
-}
-
-int btrfs_add_ordered_extent_compress(struct btrfs_inode *inode, u64 file_offset,
-				      u64 disk_bytenr, u64 num_bytes,
-				      u64 disk_num_bytes, int compress_type)
-{
-	ASSERT(compress_type != BTRFS_COMPRESS_NONE);
-	return __btrfs_add_ordered_extent(inode, file_offset, disk_bytenr,
-					  num_bytes, disk_num_bytes,
-					  BTRFS_ORDERED_COMPRESSED, 0,
-					  compress_type);
-}
-
 /*
  * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
  * when an ordered extent is finished.  If the list covers more than one
@@ -1051,35 +1024,12 @@ static int clone_ordered_extent(struct btrfs_ordered_extent *ordered, u64 pos,
 	struct inode *inode = ordered->inode;
 	u64 file_offset = ordered->file_offset + pos;
 	u64 disk_bytenr = ordered->disk_bytenr + pos;
-	u64 num_bytes = len;
-	u64 disk_num_bytes = len;
-	int type;
-	unsigned long flags_masked = ordered->flags & ~(1 << BTRFS_ORDERED_DIRECT);
-	int compress_type = ordered->compress_type;
-	unsigned long weight;
-	int ret;
+	unsigned long flags = ordered->flags & BTRFS_ORDERED_TYPE_FLAGS;
 
-	weight = hweight_long(flags_masked);
-	WARN_ON_ONCE(weight > 1);
-	if (!weight)
-		type = 0;
-	else
-		type = __ffs(flags_masked);
-
-	if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered->flags)) {
-		WARN_ON_ONCE(1);
-		ret = btrfs_add_ordered_extent_compress(BTRFS_I(inode),
-				file_offset, disk_bytenr, num_bytes,
-				disk_num_bytes, compress_type);
-	} else if (test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags)) {
-		ret = btrfs_add_ordered_extent_dio(BTRFS_I(inode), file_offset,
-				disk_bytenr, num_bytes, disk_num_bytes, type);
-	} else {
-		ret = btrfs_add_ordered_extent(BTRFS_I(inode), file_offset,
-				disk_bytenr, num_bytes, disk_num_bytes, type);
-	}
-
-	return ret;
+	WARN_ON_ONCE(flags & (1 << BTRFS_ORDERED_COMPRESSED));
+	return btrfs_add_ordered_extent(BTRFS_I(inode), file_offset, len, len,
+					disk_bytenr, len, 0, flags,
+					ordered->compress_type);
 }
 
 int btrfs_split_ordered_extent(struct btrfs_ordered_extent *ordered, u64 pre,
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index 4194e960ff61..0feb0c29839e 100644
--- a/fs/btrfs/ordered-data.h
+++ b/fs/btrfs/ordered-data.h
@@ -76,6 +76,13 @@ enum {
 	BTRFS_ORDERED_PENDING,
 };
 
+/* BTRFS_ORDERED_* flags that specify the type of the extent. */
+#define BTRFS_ORDERED_TYPE_FLAGS ((1UL << BTRFS_ORDERED_REGULAR) |	\
+				  (1UL << BTRFS_ORDERED_NOCOW) |	\
+				  (1UL << BTRFS_ORDERED_PREALLOC) |	\
+				  (1UL << BTRFS_ORDERED_COMPRESSED) |	\
+				  (1UL << BTRFS_ORDERED_DIRECT))
+
 struct btrfs_ordered_extent {
 	/* logical offset in the file */
 	u64 file_offset;
@@ -84,9 +91,11 @@ struct btrfs_ordered_extent {
 	 * These fields directly correspond to the same fields in
 	 * btrfs_file_extent_item.
 	 */
-	u64 disk_bytenr;
 	u64 num_bytes;
+	u64 ram_bytes;
+	u64 disk_bytenr;
 	u64 disk_num_bytes;
+	u64 offset;
 
 	/* number of bytes that still need writing */
 	u64 bytes_left;
@@ -179,14 +188,9 @@ bool btrfs_dec_test_ordered_pending(struct btrfs_inode *inode,
 				    struct btrfs_ordered_extent **cached,
 				    u64 file_offset, u64 io_size);
 int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset,
-			     u64 disk_bytenr, u64 num_bytes, u64 disk_num_bytes,
-			     int type);
-int btrfs_add_ordered_extent_dio(struct btrfs_inode *inode, u64 file_offset,
-				 u64 disk_bytenr, u64 num_bytes,
-				 u64 disk_num_bytes, int type);
-int btrfs_add_ordered_extent_compress(struct btrfs_inode *inode, u64 file_offset,
-				      u64 disk_bytenr, u64 num_bytes,
-				      u64 disk_num_bytes, int compress_type);
+			     u64 num_bytes, u64 ram_bytes, u64 disk_bytenr,
+			     u64 disk_num_bytes, u64 offset, int flags,
+			     int compress_type);
 void btrfs_add_ordered_sum(struct btrfs_ordered_extent *entry,
 			   struct btrfs_ordered_sum *sum);
 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct btrfs_inode *inode,
-- 
2.32.0

[PATCH v10 05/14] btrfs: support different disk extent size for delalloc

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

Currently, we always reserve the same extent size in the file and extent
size on disk for delalloc because the former is the worst case for the
latter. For RWF_ENCODED writes, we know the exact size of the extent on
disk, which may be less than or greater than (for bookends) the size in
the file. Add a disk_num_bytes parameter to
btrfs_delalloc_reserve_metadata() so that we can reserve the correct
amount of csum bytes. No functional change.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 fs/btrfs/ctree.h          |  3 ++-
 fs/btrfs/delalloc-space.c | 18 ++++++++++--------
 fs/btrfs/file.c           |  3 ++-
 fs/btrfs/inode.c          |  2 +-
 fs/btrfs/relocation.c     |  2 +-
 5 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index be245b4b8efe..973616d80080 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2798,7 +2798,8 @@ void btrfs_subvolume_release_metadata(struct btrfs_root *root,
 				      struct btrfs_block_rsv *rsv);
 void btrfs_delalloc_release_extents(struct btrfs_inode *inode, u64 num_bytes);
 
-int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes);
+int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes,
+				    u64 disk_num_bytes);
 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo);
 int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
 				   u64 start, u64 end);
diff --git a/fs/btrfs/delalloc-space.c b/fs/btrfs/delalloc-space.c
index 2059d1504149..143650004991 100644
--- a/fs/btrfs/delalloc-space.c
+++ b/fs/btrfs/delalloc-space.c
@@ -267,11 +267,11 @@ static void btrfs_calculate_inode_block_rsv_size(struct btrfs_fs_info *fs_info,
 }
 
 static void calc_inode_reservations(struct btrfs_fs_info *fs_info,
-				    u64 num_bytes, u64 *meta_reserve,
-				    u64 *qgroup_reserve)
+				    u64 num_bytes, u64 disk_num_bytes,
+				    u64 *meta_reserve, u64 *qgroup_reserve)
 {
 	u64 nr_extents = count_max_extents(num_bytes);
-	u64 csum_leaves = btrfs_csum_bytes_to_leaves(fs_info, num_bytes);
+	u64 csum_leaves = btrfs_csum_bytes_to_leaves(fs_info, disk_num_bytes);
 	u64 inode_update = btrfs_calc_metadata_size(fs_info, 1);
 
 	*meta_reserve = btrfs_calc_insert_metadata_size(fs_info,
@@ -285,7 +285,8 @@ static void calc_inode_reservations(struct btrfs_fs_info *fs_info,
 	*qgroup_reserve = nr_extents * fs_info->nodesize;
 }
 
-int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes)
+int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes,
+				    u64 disk_num_bytes)
 {
 	struct btrfs_root *root = inode->root;
 	struct btrfs_fs_info *fs_info = root->fs_info;
@@ -315,6 +316,7 @@ int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes)
 	}
 
 	num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
+	disk_num_bytes = ALIGN(disk_num_bytes, fs_info->sectorsize);
 
 	/*
 	 * We always want to do it this way, every other way is wrong and ends
@@ -326,8 +328,8 @@ int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes)
 	 * everything out and try again, which is bad.  This way we just
 	 * over-reserve slightly, and clean up the mess when we are done.
 	 */
-	calc_inode_reservations(fs_info, num_bytes, &meta_reserve,
-				&qgroup_reserve);
+	calc_inode_reservations(fs_info, num_bytes, disk_num_bytes,
+				&meta_reserve, &qgroup_reserve);
 	ret = btrfs_qgroup_reserve_meta_prealloc(root, qgroup_reserve, true);
 	if (ret)
 		return ret;
@@ -346,7 +348,7 @@ int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes)
 	spin_lock(&inode->lock);
 	nr_extents = count_max_extents(num_bytes);
 	btrfs_mod_outstanding_extents(inode, nr_extents);
-	inode->csum_bytes += num_bytes;
+	inode->csum_bytes += disk_num_bytes;
 	btrfs_calculate_inode_block_rsv_size(fs_info, inode);
 	spin_unlock(&inode->lock);
 
@@ -451,7 +453,7 @@ int btrfs_delalloc_reserve_space(struct btrfs_inode *inode,
 	ret = btrfs_check_data_free_space(inode, reserved, start, len);
 	if (ret < 0)
 		return ret;
-	ret = btrfs_delalloc_reserve_metadata(inode, len);
+	ret = btrfs_delalloc_reserve_metadata(inode, len, len);
 	if (ret < 0)
 		btrfs_free_reserved_data_space(inode, *reserved, start, len);
 	return ret;
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 7ff577005d0f..6f9cb8baffd2 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1741,7 +1741,8 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
 					 fs_info->sectorsize);
 		WARN_ON(reserve_bytes == 0);
 		ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
-				reserve_bytes);
+						      reserve_bytes,
+						      reserve_bytes);
 		if (ret) {
 			if (!only_release_metadata)
 				btrfs_free_reserved_data_space(BTRFS_I(inode),
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 67db9d0a79ec..708d8ab098bc 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5039,7 +5039,7 @@ int btrfs_truncate_block(struct btrfs_inode *inode, loff_t from, loff_t len,
 			goto out;
 		}
 	}
-	ret = btrfs_delalloc_reserve_metadata(inode, blocksize);
+	ret = btrfs_delalloc_reserve_metadata(inode, blocksize, blocksize);
 	if (ret < 0) {
 		if (!only_release_metadata)
 			btrfs_free_reserved_data_space(inode, data_reserved,
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 914d403b4415..42080f0c88ed 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -3016,7 +3016,7 @@ static int relocate_one_page(struct inode *inode, struct file_ra_state *ra,
 
 		/* Reserve metadata for this range */
 		ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
-						      clamped_len);
+						      clamped_len, clamped_len);
 		if (ret)
 			goto release_page;
 
-- 
2.32.0

[PATCH v10 06/14] btrfs: optionally extend i_size in cow_file_range_inline()

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

Currently, an inline extent is always created after i_size is extended
from btrfs_dirty_pages(). However, for encoded writes, we only want to
update i_size after we successfully created the inline extent. Add an
update_i_size parameter to cow_file_range_inline() and
insert_inline_extent() and pass in the size of the extent rather than
determining it from i_size. Since the start parameter is always passed
as 0, get rid of it and simplify the logic in these two functions. While
we're here, let's document the requirements for creating an inline
extent.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 fs/btrfs/inode.c | 100 +++++++++++++++++++++++------------------------
 1 file changed, 48 insertions(+), 52 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 708d8ab098bc..0b5ff14aa7fd 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -236,9 +236,10 @@ static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 static int insert_inline_extent(struct btrfs_trans_handle *trans,
 				struct btrfs_path *path, bool extent_inserted,
 				struct btrfs_root *root, struct inode *inode,
-				u64 start, size_t size, size_t compressed_size,
+				size_t size, size_t compressed_size,
 				int compress_type,
-				struct page **compressed_pages)
+				struct page **compressed_pages,
+				bool update_i_size)
 {
 	struct extent_buffer *leaf;
 	struct page *page = NULL;
@@ -247,7 +248,7 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
 	struct btrfs_file_extent_item *ei;
 	int ret;
 	size_t cur_size = size;
-	unsigned long offset;
+	u64 i_size;
 
 	ASSERT((compressed_size > 0 && compressed_pages) ||
 	       (compressed_size == 0 && !compressed_pages));
@@ -260,7 +261,7 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
 		size_t datasize;
 
 		key.objectid = btrfs_ino(BTRFS_I(inode));
-		key.offset = start;
+		key.offset = 0;
 		key.type = BTRFS_EXTENT_DATA_KEY;
 
 		datasize = btrfs_file_extent_calc_inline_size(cur_size);
@@ -297,12 +298,10 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
 		btrfs_set_file_extent_compression(leaf, ei,
 						  compress_type);
 	} else {
-		page = find_get_page(inode->i_mapping,
-				     start >> PAGE_SHIFT);
+		page = find_get_page(inode->i_mapping, 0);
 		btrfs_set_file_extent_compression(leaf, ei, 0);
 		kaddr = kmap_atomic(page);
-		offset = offset_in_page(start);
-		write_extent_buffer(leaf, kaddr + offset, ptr, size);
+		write_extent_buffer(leaf, kaddr, ptr, size);
 		kunmap_atomic(kaddr);
 		put_page(page);
 	}
@@ -313,8 +312,8 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
 	 * We align size to sectorsize for inline extents just for simplicity
 	 * sake.
 	 */
-	size = ALIGN(size, root->fs_info->sectorsize);
-	ret = btrfs_inode_set_file_extent_range(BTRFS_I(inode), start, size);
+	ret = btrfs_inode_set_file_extent_range(BTRFS_I(inode), 0,
+					ALIGN(size, root->fs_info->sectorsize));
 	if (ret)
 		goto fail;
 
@@ -327,7 +326,13 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
 	 * before we unlock the pages.  Otherwise we
 	 * could end up racing with unlink.
 	 */
-	BTRFS_I(inode)->disk_i_size = inode->i_size;
+	i_size = i_size_read(inode);
+	if (update_i_size && size > i_size) {
+		i_size_write(inode, size);
+		i_size = size;
+	}
+	BTRFS_I(inode)->disk_i_size = i_size;
+
 fail:
 	return ret;
 }
@@ -338,35 +343,31 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
  * does the checks required to make sure the data is small enough
  * to fit as an inline extent.
  */
-static noinline int cow_file_range_inline(struct btrfs_inode *inode, u64 start,
-					  u64 end, size_t compressed_size,
+static noinline int cow_file_range_inline(struct btrfs_inode *inode, u64 size,
+					  size_t compressed_size,
 					  int compress_type,
-					  struct page **compressed_pages)
+					  struct page **compressed_pages,
+					  bool update_i_size)
 {
 	struct btrfs_drop_extents_args drop_args = { 0 };
 	struct btrfs_root *root = inode->root;
 	struct btrfs_fs_info *fs_info = root->fs_info;
 	struct btrfs_trans_handle *trans;
-	u64 isize = i_size_read(&inode->vfs_inode);
-	u64 actual_end = min(end + 1, isize);
-	u64 inline_len = actual_end - start;
-	u64 aligned_end = ALIGN(end, fs_info->sectorsize);
-	u64 data_len = inline_len;
+	u64 data_len = compressed_size ? compressed_size : size;
 	int ret;
 	struct btrfs_path *path;
 
-	if (compressed_size)
-		data_len = compressed_size;
-
-	if (start > 0 ||
-	    actual_end > fs_info->sectorsize ||
+	/*
+	 * We can create an inline extent if it ends at or beyond the current
+	 * i_size, is no larger than a sector (decompressed), and the (possibly
+	 * compressed) data fits in a leaf and the configured maximum inline
+	 * size.
+	 */
+	if (size < i_size_read(&inode->vfs_inode) ||
+	    size > fs_info->sectorsize ||
 	    data_len > BTRFS_MAX_INLINE_DATA_SIZE(fs_info) ||
-	    (!compressed_size &&
-	    (actual_end & (fs_info->sectorsize - 1)) == 0) ||
-	    end + 1 < isize ||
-	    data_len > fs_info->max_inline) {
+	    data_len > fs_info->max_inline)
 		return 1;
-	}
 
 	path = btrfs_alloc_path();
 	if (!path)
@@ -380,30 +381,21 @@ static noinline int cow_file_range_inline(struct btrfs_inode *inode, u64 start,
 	trans->block_rsv = &inode->block_rsv;
 
 	drop_args.path = path;
-	drop_args.start = start;
-	drop_args.end = aligned_end;
+	drop_args.start = 0;
+	drop_args.end = fs_info->sectorsize;
 	drop_args.drop_cache = true;
 	drop_args.replace_extent = true;
-
-	if (compressed_size && compressed_pages)
-		drop_args.extent_item_size = btrfs_file_extent_calc_inline_size(
-		   compressed_size);
-	else
-		drop_args.extent_item_size = btrfs_file_extent_calc_inline_size(
-		    inline_len);
-
+	drop_args.extent_item_size = btrfs_file_extent_calc_inline_size(data_len);
 	ret = btrfs_drop_extents(trans, root, inode, &drop_args);
 	if (ret) {
 		btrfs_abort_transaction(trans, ret);
 		goto out;
 	}
 
-	if (isize > actual_end)
-		inline_len = min_t(u64, isize, actual_end);
-	ret = insert_inline_extent(trans, path, drop_args.extent_inserted,
-				   root, &inode->vfs_inode, start,
-				   inline_len, compressed_size,
-				   compress_type, compressed_pages);
+	ret = insert_inline_extent(trans, path, drop_args.extent_inserted, root,
+				   &inode->vfs_inode, size, compressed_size,
+				   compress_type, compressed_pages,
+				   update_i_size);
 	if (ret && ret != -ENOSPC) {
 		btrfs_abort_transaction(trans, ret);
 		goto out;
@@ -412,7 +404,7 @@ static noinline int cow_file_range_inline(struct btrfs_inode *inode, u64 start,
 		goto out;
 	}
 
-	btrfs_update_inode_bytes(inode, inline_len, drop_args.bytes_found);
+	btrfs_update_inode_bytes(inode, size, drop_args.bytes_found);
 	ret = btrfs_update_inode(trans, root, inode);
 	if (ret && ret != -ENOSPC) {
 		btrfs_abort_transaction(trans, ret);
@@ -695,14 +687,15 @@ static noinline int compress_file_range(struct async_chunk *async_chunk)
 			/* we didn't compress the entire range, try
 			 * to make an uncompressed inline extent.
 			 */
-			ret = cow_file_range_inline(BTRFS_I(inode), start, end,
+			ret = cow_file_range_inline(BTRFS_I(inode), actual_end,
 						    0, BTRFS_COMPRESS_NONE,
-						    NULL);
+						    NULL, false);
 		} else {
 			/* try making a compressed inline extent */
-			ret = cow_file_range_inline(BTRFS_I(inode), start, end,
+			ret = cow_file_range_inline(BTRFS_I(inode), actual_end,
 						    total_compressed,
-						    compress_type, pages);
+						    compress_type, pages,
+						    false);
 		}
 		if (ret <= 0) {
 			unsigned long clear_flags = EXTENT_DELALLOC |
@@ -1098,9 +1091,12 @@ static noinline int cow_file_range(struct btrfs_inode *inode,
 	 * So here we skip inline extent creation completely.
 	 */
 	if (start == 0 && fs_info->sectorsize == PAGE_SIZE) {
+		u64 actual_end = min_t(u64, i_size_read(&inode->vfs_inode),
+				       end + 1);
+
 		/* lets try to make an inline extent */
-		ret = cow_file_range_inline(inode, start, end, 0,
-					    BTRFS_COMPRESS_NONE, NULL);
+		ret = cow_file_range_inline(inode, actual_end, 0,
+					    BTRFS_COMPRESS_NONE, NULL, false);
 		if (ret == 0) {
 			/*
 			 * We use DO_ACCOUNTING here because we need the
-- 
2.32.0

[PATCH v10 07/14] btrfs: add definitions + documentation for encoded I/O ioctls

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

In order to allow sending and receiving compressed data without
decompressing it, we need an interface to write pre-compressed data
directly to the filesystem and the matching interface to read compressed
data without decompressing it. This adds the definitions for ioctls to
do that and detailed explanations of how to use them.

Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 include/uapi/linux/btrfs.h | 132 +++++++++++++++++++++++++++++++++++++
 1 file changed, 132 insertions(+)

diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index d7d3cfead056..95da52955894 100644
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -861,6 +861,134 @@ struct btrfs_ioctl_get_subvol_rootref_args {
 		__u8 align[7];
 };
 
+/*
+ * Data and metadata for an encoded read or write.
+ *
+ * Encoded I/O bypasses any encoding automatically done by the filesystem (e.g.,
+ * compression). This can be used to read the compressed contents of a file or
+ * write pre-compressed data directly to a file.
+ *
+ * BTRFS_IOC_ENCODED_READ and BTRFS_IOC_ENCODED_WRITE are essentially
+ * preadv/pwritev with additional metadata about how the data is encoded and the
+ * size of the unencoded data.
+ *
+ * BTRFS_IOC_ENCODED_READ fills the given iovecs with the encoded data, fills
+ * the metadata fields, and returns the size of the encoded data. It reads one
+ * extent per call. It can also read data which is not encoded.
+ *
+ * BTRFS_IOC_ENCODED_WRITE uses the metadata fields, writes the encoded data
+ * from the iovecs, and returns the size of the encoded data. Note that the
+ * encoded data is not validated when it is written; if it is not valid (e.g.,
+ * it cannot be decompressed), then a subsequent read may return an error.
+ *
+ * Since the filesystem page cache contains decoded data, encoded I/O bypasses
+ * the page cache. Encoded I/O requires CAP_SYS_ADMIN.
+ */
+struct btrfs_ioctl_encoded_io_args {
+	/* Input parameters for both reads and writes. */
+
+	/*
+	 * iovecs containing encoded data.
+	 *
+	 * For reads, if the size of the encoded data is larger than the sum of
+	 * iov[n].iov_len for 0 <= n < iovcnt, then the ioctl fails with
+	 * ENOBUFS.
+	 *
+	 * For writes, the size of the encoded data is the sum of iov[n].iov_len
+	 * for 0 <= n < iovcnt. This must be less than 128 KiB (this limit may
+	 * increase in the future). This must also be less than or equal to
+	 * unencoded_len.
+	 */
+	const struct iovec __user *iov;
+	/* Number of iovecs. */
+	unsigned long iovcnt;
+	/*
+	 * Offset in file.
+	 *
+	 * For writes, must be aligned to the sector size of the filesystem.
+	 */
+	__s64 offset;
+	/* Currently must be zero. */
+	__u64 flags;
+
+	/*
+	 * For reads, the following members are filled in with the metadata for
+	 * the encoded data.
+	 * For writes, the following members must be set to the metadata for the
+	 * encoded data.
+	 */
+
+	/*
+	 * Length of the data in the file.
+	 *
+	 * Must be less than or equal to unencoded_len - unencoded_offset. For
+	 * writes, must be aligned to the sector size of the filesystem unless
+	 * the data ends at or beyond the current end of the file.
+	 */
+	__u64 len;
+	/*
+	 * Length of the unencoded (i.e., decrypted and decompressed) data.
+	 *
+	 * For writes, must be no more than 128 KiB (this limit may increase in
+	 * the future). If the unencoded data is actually longer than
+	 * unencoded_len, then it is truncated; if it is shorter, then it is
+	 * extended with zeroes.
+	 */
+	__u64 unencoded_len;
+	/*
+	 * Offset from the first byte of the unencoded data to the first byte of
+	 * logical data in the file.
+	 *
+	 * Must be less than unencoded_len.
+	 */
+	__u64 unencoded_offset;
+	/*
+	 * BTRFS_ENCODED_IO_COMPRESSION_* type.
+	 *
+	 * For writes, must not be BTRFS_ENCODED_IO_COMPRESSION_NONE.
+	 */
+	__u32 compression;
+	/* Currently always BTRFS_ENCODED_IO_ENCRYPTION_NONE. */
+	__u32 encryption;
+	/*
+	 * Reserved for future expansion.
+	 *
+	 * For reads, always returned as zero. Users should check for non-zero
+	 * bytes. If there are any, then the kernel has a newer version of this
+	 * structure with additional information that the user definition is
+	 * missing.
+	 *
+	 * For writes, must be zeroed.
+	 */
+	__u8 reserved[32];
+};
+
+/* Data is not compressed. */
+#define BTRFS_ENCODED_IO_COMPRESSION_NONE 0
+/* Data is compressed as a single zlib stream. */
+#define BTRFS_ENCODED_IO_COMPRESSION_ZLIB 1
+/*
+ * Data is compressed as a single zstd frame with the windowLog compression
+ * parameter set to no more than 17.
+ */
+#define BTRFS_ENCODED_IO_COMPRESSION_ZSTD 2
+/*
+ * Data is compressed page by page (using the page size indicated by the name of
+ * the constant) with LZO1X and wrapped in the format documented in
+ * fs/btrfs/lzo.c. For writes, the compression page size must match the
+ * filesystem page size.
+ */
+#define BTRFS_ENCODED_IO_COMPRESSION_LZO_4K 3
+#define BTRFS_ENCODED_IO_COMPRESSION_LZO_8K 4
+#define BTRFS_ENCODED_IO_COMPRESSION_LZO_16K 5
+#define BTRFS_ENCODED_IO_COMPRESSION_LZO_32K 6
+#define BTRFS_ENCODED_IO_COMPRESSION_LZO_64K 7
+#define BTRFS_ENCODED_IO_COMPRESSION_TYPES 8
+
+/* Data is not encrypted. */
+#define BTRFS_ENCODED_IO_ENCRYPTION_NONE 0
+#define BTRFS_ENCODED_IO_ENCRYPTION_TYPES 1
+
 /* Error codes as returned by the kernel */
 enum btrfs_err_code {
 	BTRFS_ERROR_DEV_RAID1_MIN_NOT_MET = 1,
@@ -989,5 +1117,9 @@ enum btrfs_err_code {
 				struct btrfs_ioctl_ino_lookup_user_args)
 #define BTRFS_IOC_SNAP_DESTROY_V2 _IOW(BTRFS_IOCTL_MAGIC, 63, \
 				struct btrfs_ioctl_vol_args_v2)
+#define BTRFS_IOC_ENCODED_READ _IOR(BTRFS_IOCTL_MAGIC, 64, \
+				    struct btrfs_ioctl_encoded_io_args)
+#define BTRFS_IOC_ENCODED_WRITE _IOW(BTRFS_IOCTL_MAGIC, 64, \
+				     struct btrfs_ioctl_encoded_io_args)
 
 #endif /* _UAPI_LINUX_BTRFS_H */
-- 
2.32.0

[PATCH v10 08/14] btrfs: add BTRFS_IOC_ENCODED_READ

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

There are 4 main cases:

1. Inline extents: we copy the data straight out of the extent buffer.
2. Hole/preallocated extents: we fill in zeroes.
3. Regular, uncompressed extents: we read the sectors we need directly
   from disk.
4. Regular, compressed extents: we read the entire compressed extent
   from disk and indicate what subset of the decompressed extent is in
   the file.

This initial implementation simplifies a few things that can be improved
in the future:

- We hold the inode lock during the operation.
- Cases 1, 3, and 4 allocate temporary memory to read into before
  copying out to userspace.
- We don't do read repair, because it turns out that read repair is
  currently broken for compressed data.

Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 fs/btrfs/ctree.h |   4 +
 fs/btrfs/inode.c | 489 +++++++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/ioctl.c | 111 +++++++++++
 3 files changed, 604 insertions(+)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 973616d80080..b68d8ea42f6e 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3219,6 +3219,10 @@ int btrfs_writepage_cow_fixup(struct page *page);
 void btrfs_writepage_endio_finish_ordered(struct btrfs_inode *inode,
 					  struct page *page, u64 start,
 					  u64 end, bool uptodate);
+struct btrfs_ioctl_encoded_io_args;
+ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter,
+			   struct btrfs_ioctl_encoded_io_args *encoded);
+
 extern const struct dentry_operations btrfs_dentry_operations;
 extern const struct iomap_ops btrfs_dio_iomap_ops;
 extern const struct iomap_dio_ops btrfs_dio_ops;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 0b5ff14aa7fd..6d7fae859fb5 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -10496,6 +10496,495 @@ void btrfs_set_range_writeback(struct btrfs_inode *inode, u64 start, u64 end)
 	}
 }
 
+static int btrfs_encoded_io_compression_from_extent(int compress_type)
+{
+	switch (compress_type) {
+	case BTRFS_COMPRESS_NONE:
+		return BTRFS_ENCODED_IO_COMPRESSION_NONE;
+	case BTRFS_COMPRESS_ZLIB:
+		return BTRFS_ENCODED_IO_COMPRESSION_ZLIB;
+	case BTRFS_COMPRESS_LZO:
+		/*
+		 * The LZO format depends on the page size. 64k is the maximum
+		 * sectorsize (and thus page size) that we support.
+		 */
+		if (PAGE_SIZE < SZ_4K || PAGE_SIZE > SZ_64K)
+			return -EINVAL;
+		return BTRFS_ENCODED_IO_COMPRESSION_LZO_4K + (PAGE_SHIFT - 12);
+	case BTRFS_COMPRESS_ZSTD:
+		return BTRFS_ENCODED_IO_COMPRESSION_ZSTD;
+	default:
+		return -EUCLEAN;
+	}
+}
+
+static ssize_t btrfs_encoded_read_inline(
+				struct kiocb *iocb,
+				struct iov_iter *iter, u64 start,
+				u64 lockend,
+				struct extent_state **cached_state,
+				u64 extent_start, size_t count,
+				struct btrfs_ioctl_encoded_io_args *encoded,
+				bool *unlocked)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+	struct btrfs_path *path;
+	struct extent_buffer *leaf;
+	struct btrfs_file_extent_item *item;
+	u64 ram_bytes;
+	unsigned long ptr;
+	void *tmp;
+	ssize_t ret;
+
+	path = btrfs_alloc_path();
+	if (!path) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root, path,
+				       btrfs_ino(BTRFS_I(inode)), extent_start,
+				       0);
+	if (ret) {
+		if (ret > 0) {
+			/* The extent item disappeared? */
+			ret = -EIO;
+		}
+		goto out;
+	}
+	leaf = path->nodes[0];
+	item = btrfs_item_ptr(leaf, path->slots[0],
+			      struct btrfs_file_extent_item);
+
+	ram_bytes = btrfs_file_extent_ram_bytes(leaf, item);
+	ptr = btrfs_file_extent_inline_start(item);
+
+	encoded->len = (min_t(u64, extent_start + ram_bytes, inode->i_size) -
+			iocb->ki_pos);
+	ret = btrfs_encoded_io_compression_from_extent(
+				 btrfs_file_extent_compression(leaf, item));
+	if (ret < 0)
+		goto out;
+	encoded->compression = ret;
+	if (encoded->compression) {
+		size_t inline_size;
+
+		inline_size = btrfs_file_extent_inline_item_len(leaf,
+						btrfs_item_nr(path->slots[0]));
+		if (inline_size > count) {
+			ret = -ENOBUFS;
+			goto out;
+		}
+		count = inline_size;
+		encoded->unencoded_len = ram_bytes;
+		encoded->unencoded_offset = iocb->ki_pos - extent_start;
+	} else {
+		encoded->len = encoded->unencoded_len = count =
+			min_t(u64, count, encoded->len);
+		ptr += iocb->ki_pos - extent_start;
+	}
+
+	tmp = kmalloc(count, GFP_NOFS);
+	if (!tmp) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	read_extent_buffer(leaf, tmp, ptr, count);
+	btrfs_release_path(path);
+	unlock_extent_cached(io_tree, start, lockend, cached_state);
+	inode_unlock_shared(inode);
+	*unlocked = true;
+
+	ret = copy_to_iter(tmp, count, iter);
+	if (ret != count)
+		ret = -EFAULT;
+	kfree(tmp);
+out:
+	btrfs_free_path(path);
+	return ret;
+}
+
+struct btrfs_encoded_read_private {
+	struct inode *inode;
+	wait_queue_head_t wait;
+	atomic_t pending;
+	blk_status_t status;
+	bool skip_csum;
+};
+
+static blk_status_t submit_encoded_read_bio(struct inode *inode,
+					    struct bio *bio, int mirror_num,
+					    unsigned long bio_flags)
+{
+	struct btrfs_encoded_read_private *priv = bio->bi_private;
+	struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
+	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+	blk_status_t ret;
+
+	if (!priv->skip_csum) {
+		ret = btrfs_lookup_bio_sums(inode, bio, NULL);
+		if (ret)
+			return ret;
+	}
+
+	ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DATA);
+	if (ret) {
+		btrfs_io_bio_free_csum(io_bio);
+		return ret;
+	}
+
+	atomic_inc(&priv->pending);
+	ret = btrfs_map_bio(fs_info, bio, mirror_num);
+	if (ret) {
+		atomic_dec(&priv->pending);
+		btrfs_io_bio_free_csum(io_bio);
+	}
+	return ret;
+}
+
+static blk_status_t btrfs_encoded_read_check_bio(struct btrfs_io_bio *io_bio)
+{
+	const bool uptodate = io_bio->bio.bi_status == BLK_STS_OK;
+	struct btrfs_encoded_read_private *priv = io_bio->bio.bi_private;
+	struct inode *inode = priv->inode;
+	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+	u32 sectorsize = fs_info->sectorsize;
+	struct bio_vec *bvec;
+	struct bvec_iter_all iter_all;
+	u64 start = io_bio->logical;
+	u32 bio_offset = 0;
+
+	if (priv->skip_csum || !uptodate)
+		return io_bio->bio.bi_status;
+
+	bio_for_each_segment_all(bvec, &io_bio->bio, iter_all) {
+		unsigned int i, nr_sectors, pgoff;
+
+		nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);
+		pgoff = bvec->bv_offset;
+		for (i = 0; i < nr_sectors; i++) {
+			ASSERT(pgoff < PAGE_SIZE);
+			if (check_data_csum(inode, io_bio, bio_offset,
+					    bvec->bv_page, pgoff, start))
+				return BLK_STS_IOERR;
+			start += sectorsize;
+			bio_offset += sectorsize;
+			pgoff += sectorsize;
+		}
+	}
+	return BLK_STS_OK;
+}
+
+static void btrfs_encoded_read_endio(struct bio *bio)
+{
+	struct btrfs_encoded_read_private *priv = bio->bi_private;
+	struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
+	blk_status_t status;
+
+	status = btrfs_encoded_read_check_bio(io_bio);
+	if (status) {
+		/*
+		 * The memory barrier implied by the atomic_dec_return() here
+		 * pairs with the memory barrier implied by the
+		 * atomic_dec_return() or io_wait_event() in
+		 * btrfs_encoded_read_regular_fill_pages() to ensure that this
+		 * write is observed before the load of status in
+		 * btrfs_encoded_read_regular_fill_pages().
+		 */
+		WRITE_ONCE(priv->status, status);
+	}
+	if (!atomic_dec_return(&priv->pending))
+		wake_up(&priv->wait);
+	btrfs_io_bio_free_csum(io_bio);
+	bio_put(bio);
+}
+
+static int btrfs_encoded_read_regular_fill_pages(struct inode *inode, u64 offset,
+						 u64 disk_io_size, struct page **pages)
+{
+	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+	struct btrfs_encoded_read_private priv = {
+		.inode = inode,
+		.pending = ATOMIC_INIT(1),
+		.skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM,
+	};
+	unsigned long i = 0;
+	u64 cur = 0;
+	int ret;
+
+	init_waitqueue_head(&priv.wait);
+	/*
+	 * Submit bios for the extent, splitting due to bio or stripe limits as
+	 * necessary.
+	 */
+	while (cur < disk_io_size) {
+		struct extent_map *em;
+		struct btrfs_io_geometry geom;
+		struct bio *bio = NULL;
+		u64 remaining;
+
+		em = btrfs_get_chunk_map(fs_info, offset + cur,
+					 disk_io_size - cur);
+		if (IS_ERR(em)) {
+			ret = PTR_ERR(em);
+		} else {
+			ret = btrfs_get_io_geometry(fs_info, em, BTRFS_MAP_READ,
+						    offset + cur, &geom);
+			free_extent_map(em);
+		}
+		if (ret) {
+			WRITE_ONCE(priv.status, errno_to_blk_status(ret));
+			break;
+		}
+		remaining = min(geom.len, disk_io_size - cur);
+		while (bio || remaining) {
+			size_t bytes = min_t(u64, remaining, PAGE_SIZE);
+
+			if (!bio) {
+				bio = btrfs_bio_alloc(offset + cur);
+				bio->bi_end_io = btrfs_encoded_read_endio;
+				bio->bi_private = &priv;
+				bio->bi_opf = REQ_OP_READ;
+			}
+
+			if (!bytes ||
+			    bio_add_page(bio, pages[i], bytes, 0) < bytes) {
+				blk_status_t status;
+
+				status = submit_encoded_read_bio(inode, bio, 0,
+								 0);
+				if (status) {
+					WRITE_ONCE(priv.status, status);
+					bio_put(bio);
+					goto out;
+				}
+				bio = NULL;
+				continue;
+			}
+
+			i++;
+			cur += bytes;
+			remaining -= bytes;
+		}
+	}
+
+out:
+	if (atomic_dec_return(&priv.pending))
+		io_wait_event(priv.wait, !atomic_read(&priv.pending));
+	/* See btrfs_encoded_read_endio() for ordering. */
+	return blk_status_to_errno(READ_ONCE(priv.status));
+}
+
+static ssize_t btrfs_encoded_read_regular(struct kiocb *iocb,
+					  struct iov_iter *iter,
+					  u64 start, u64 lockend,
+					  struct extent_state **cached_state,
+					  u64 offset, u64 disk_io_size,
+					  size_t count, bool compressed,
+					  bool *unlocked)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+	struct page **pages;
+	unsigned long nr_pages, i;
+	u64 cur;
+	size_t page_offset;
+	ssize_t ret;
+
+	nr_pages = DIV_ROUND_UP(disk_io_size, PAGE_SIZE);
+	pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
+	if (!pages)
+		return -ENOMEM;
+	for (i = 0; i < nr_pages; i++) {
+		pages[i] = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
+		if (!pages[i]) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	}
+
+	ret = btrfs_encoded_read_regular_fill_pages(inode, offset, disk_io_size,
+						    pages);
+	if (ret)
+		goto out;
+
+	unlock_extent_cached(io_tree, start, lockend, cached_state);
+	inode_unlock_shared(inode);
+	*unlocked = true;
+
+	if (compressed) {
+		i = 0;
+		page_offset = 0;
+	} else {
+		i = (iocb->ki_pos - start) >> PAGE_SHIFT;
+		page_offset = (iocb->ki_pos - start) & (PAGE_SIZE - 1);
+	}
+	cur = 0;
+	while (cur < count) {
+		size_t bytes = min_t(size_t, count - cur,
+				     PAGE_SIZE - page_offset);
+
+		if (copy_page_to_iter(pages[i], page_offset, bytes,
+				      iter) != bytes) {
+			ret = -EFAULT;
+			goto out;
+		}
+		i++;
+		cur += bytes;
+		page_offset = 0;
+	}
+	ret = count;
+out:
+	for (i = 0; i < nr_pages; i++) {
+		if (pages[i])
+			__free_page(pages[i]);
+	}
+	kfree(pages);
+	return ret;
+}
+
+ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter,
+			   struct btrfs_ioctl_encoded_io_args *encoded)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+	ssize_t ret;
+	size_t count = iov_iter_count(iter);
+	u64 start, lockend, offset, disk_io_size;
+	struct extent_state *cached_state = NULL;
+	struct extent_map *em;
+	bool unlocked = false;
+
+	file_accessed(iocb->ki_filp);
+
+	inode_lock_shared(inode);
+
+	if (iocb->ki_pos >= inode->i_size) {
+		inode_unlock_shared(inode);
+		return 0;
+	}
+	start = ALIGN_DOWN(iocb->ki_pos, fs_info->sectorsize);
+	/*
+	 * We don't know how long the extent containing iocb->ki_pos is, but if
+	 * it's compressed we know that it won't be longer than this.
+	 */
+	lockend = start + BTRFS_MAX_UNCOMPRESSED - 1;
+
+	for (;;) {
+		struct btrfs_ordered_extent *ordered;
+
+		ret = btrfs_wait_ordered_range(inode, start,
+					       lockend - start + 1);
+		if (ret)
+			goto out_unlock_inode;
+		lock_extent_bits(io_tree, start, lockend, &cached_state);
+		ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
+						     lockend - start + 1);
+		if (!ordered)
+			break;
+		btrfs_put_ordered_extent(ordered);
+		unlock_extent_cached(io_tree, start, lockend, &cached_state);
+		cond_resched();
+	}
+
+	em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start,
+			      lockend - start + 1);
+	if (IS_ERR(em)) {
+		ret = PTR_ERR(em);
+		goto out_unlock_extent;
+	}
+
+	if (em->block_start == EXTENT_MAP_INLINE) {
+		u64 extent_start = em->start;
+
+		/*
+		 * For inline extents we get everything we need out of the
+		 * extent item.
+		 */
+		free_extent_map(em);
+		em = NULL;
+		ret = btrfs_encoded_read_inline(iocb, iter, start, lockend,
+						&cached_state, extent_start,
+						count, encoded, &unlocked);
+		goto out;
+	}
+
+	/*
+	 * We only want to return up to EOF even if the extent extends beyond
+	 * that.
+	 */
+	encoded->len = (min_t(u64, extent_map_end(em), inode->i_size) -
+			iocb->ki_pos);
+	if (em->block_start == EXTENT_MAP_HOLE ||
+	    test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
+		offset = EXTENT_MAP_HOLE;
+		encoded->len = encoded->unencoded_len = count =
+			min_t(u64, count, encoded->len);
+	} else if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
+		offset = em->block_start;
+		/*
+		 * Bail if the buffer isn't large enough to return the whole
+		 * compressed extent.
+		 */
+		if (em->block_len > count) {
+			ret = -ENOBUFS;
+			goto out_em;
+		}
+		disk_io_size = count = em->block_len;
+		encoded->unencoded_len = em->ram_bytes;
+		encoded->unencoded_offset = iocb->ki_pos - em->orig_start;
+		ret = btrfs_encoded_io_compression_from_extent(
+							     em->compress_type);
+		if (ret < 0)
+			goto out_em;
+		encoded->compression = ret;
+	} else {
+		offset = em->block_start + (start - em->start);
+		if (encoded->len > count)
+			encoded->len = count;
+		/*
+		 * Don't read beyond what we locked. This also limits the page
+		 * allocations that we'll do.
+		 */
+		disk_io_size = min(lockend + 1,
+				   iocb->ki_pos + encoded->len) - start;
+		encoded->len = encoded->unencoded_len = count =
+			start + disk_io_size - iocb->ki_pos;
+		disk_io_size = ALIGN(disk_io_size, fs_info->sectorsize);
+	}
+	free_extent_map(em);
+	em = NULL;
+
+	if (offset == EXTENT_MAP_HOLE) {
+		unlock_extent_cached(io_tree, start, lockend, &cached_state);
+		inode_unlock_shared(inode);
+		unlocked = true;
+		ret = iov_iter_zero(count, iter);
+		if (ret != count)
+			ret = -EFAULT;
+	} else {
+		ret = btrfs_encoded_read_regular(iocb, iter, start, lockend,
+						 &cached_state, offset,
+						 disk_io_size, count,
+						 encoded->compression,
+						 &unlocked);
+	}
+
+out:
+	if (ret >= 0)
+		iocb->ki_pos += encoded->len;
+out_em:
+	free_extent_map(em);
+out_unlock_extent:
+	if (!unlocked)
+		unlock_extent_cached(io_tree, start, lockend, &cached_state);
+out_unlock_inode:
+	if (!unlocked)
+		inode_unlock_shared(inode);
+	return ret;
+}
+
 #ifdef CONFIG_SWAP
 /*
  * Add an entry indicating a block group or device which is pinned by a
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 41524f9aeac3..7a0a9c752624 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -28,6 +28,7 @@
 #include <linux/iversion.h>
 #include <linux/fileattr.h>
 #include <linux/fsverity.h>
+#include <linux/sched/xacct.h>
 #include "ctree.h"
 #include "disk-io.h"
 #include "export.h"
@@ -86,6 +87,22 @@ struct btrfs_ioctl_send_args_32 {
 
 #define BTRFS_IOC_SEND_32 _IOW(BTRFS_IOCTL_MAGIC, 38, \
 			       struct btrfs_ioctl_send_args_32)
+
+struct btrfs_ioctl_encoded_io_args_32 {
+	compat_uptr_t iov;
+	compat_ulong_t iovcnt;
+	__s64 offset;
+	__u64 flags;
+	__u64 len;
+	__u64 unencoded_len;
+	__u64 unencoded_offset;
+	__u32 compression;
+	__u32 encryption;
+	__u32 reserved[8];
+};
+
+#define BTRFS_IOC_ENCODED_READ_32 _IOR(BTRFS_IOCTL_MAGIC, 64, \
+				       struct btrfs_ioctl_encoded_io_args_32)
 #endif
 
 /* Mask out flags that are inappropriate for the given type of inode. */
@@ -4887,6 +4904,94 @@ static int _btrfs_ioctl_send(struct file *file, void __user *argp, bool compat)
 	return ret;
 }
 
+static int btrfs_ioctl_encoded_read(struct file *file, void __user *argp,
+				    bool compat)
+{
+	struct btrfs_ioctl_encoded_io_args args;
+	size_t copy_end_kernel = offsetofend(struct btrfs_ioctl_encoded_io_args,
+					     flags);
+	size_t copy_end;
+	struct iovec iovstack[UIO_FASTIOV];
+	struct iovec *iov = iovstack;
+	struct iov_iter iter;
+	loff_t pos;
+	struct kiocb kiocb;
+	ssize_t ret;
+
+	if (!capable(CAP_SYS_ADMIN)) {
+		ret = -EPERM;
+		goto out_acct;
+	}
+
+	if (compat) {
+#if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
+		struct btrfs_ioctl_encoded_io_args_32 args32;
+
+		copy_end = offsetofend(struct btrfs_ioctl_encoded_io_args_32,
+				       flags);
+		if (copy_from_user(&args32, argp, copy_end)) {
+			ret = -EFAULT;
+			goto out_acct;
+		}
+		args.iov = compat_ptr(args32.iov);
+		args.iovcnt = args32.iovcnt;
+		args.offset = args32.offset;
+		args.flags = args32.flags;
+#else
+		return -ENOTTY;
+#endif
+	} else {
+		copy_end = copy_end_kernel;
+		if (copy_from_user(&args, argp, copy_end)) {
+			ret = -EFAULT;
+			goto out_acct;
+		}
+	}
+	if (args.flags != 0) {
+		ret = -EINVAL;
+		goto out_acct;
+	}
+	memset((char *)&args + copy_end_kernel, 0,
+	       sizeof(args) - copy_end_kernel);
+
+	ret = import_iovec(READ, args.iov, args.iovcnt, ARRAY_SIZE(iovstack),
+			   &iov, &iter);
+	if (ret < 0)
+		goto out_acct;
+
+	if (iov_iter_count(&iter) == 0) {
+		ret = 0;
+		goto out_iov;
+	}
+	pos = args.offset;
+	ret = rw_verify_area(READ, file, &pos, args.len);
+	if (ret < 0)
+		goto out_iov;
+
+	init_sync_kiocb(&kiocb, file);
+	ret = kiocb_set_rw_flags(&kiocb, 0);
+	if (ret)
+		goto out_iov;
+	kiocb.ki_pos = pos;
+
+	ret = btrfs_encoded_read(&kiocb, &iter, &args);
+	if (ret >= 0) {
+		fsnotify_access(file);
+		if (copy_to_user(argp + copy_end,
+				 (char *)&args + copy_end_kernel,
+				 sizeof(args) - copy_end_kernel))
+			ret = -EFAULT;
+	}
+
+out_iov:
+	kfree(iov);
+out_acct:
+	if (ret > 0)
+		add_rchar(current, ret);
+	inc_syscr(current);
+	return ret;
+}
+
 long btrfs_ioctl(struct file *file, unsigned int
 		cmd, unsigned long arg)
 {
@@ -5031,6 +5136,12 @@ long btrfs_ioctl(struct file *file, unsigned int
 		return fsverity_ioctl_enable(file, (const void __user *)argp);
 	case FS_IOC_MEASURE_VERITY:
 		return fsverity_ioctl_measure(file, argp);
+	case BTRFS_IOC_ENCODED_READ:
+		return btrfs_ioctl_encoded_read(file, argp, false);
+#if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
+	case BTRFS_IOC_ENCODED_READ_32:
+		return btrfs_ioctl_encoded_read(file, argp, true);
+#endif
 	}
 
 	return -ENOTTY;
-- 
2.32.0

[PATCH v10 09/14] btrfs: add BTRFS_IOC_ENCODED_WRITE

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

The implementation resembles direct I/O: we have to flush any ordered
extents, invalidate the page cache, and do the io tree/delalloc/extent
map/ordered extent dance. From there, we can reuse the compression code
with a minor modification to distinguish the write from writeback. This
also creates inline extents when possible.

Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 fs/btrfs/compression.c  |   7 +-
 fs/btrfs/compression.h  |   6 +-
 fs/btrfs/ctree.h        |   4 +
 fs/btrfs/file.c         |  65 ++++++++--
 fs/btrfs/inode.c        | 256 +++++++++++++++++++++++++++++++++++++++-
 fs/btrfs/ioctl.c        | 102 ++++++++++++++++
 fs/btrfs/ordered-data.c |  12 +-
 fs/btrfs/ordered-data.h |   5 +-
 8 files changed, 437 insertions(+), 20 deletions(-)

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index e645b3c2f09a..a9845aab3b18 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -353,7 +353,8 @@ static void end_compressed_bio_write(struct bio *bio)
 			cb->start, cb->start + cb->len - 1,
 			!cb->errors);
 
-	end_compressed_writeback(inode, cb);
+	if (cb->writeback)
+		end_compressed_writeback(inode, cb);
 	/* note, our inode could be gone now */
 
 	/*
@@ -389,7 +390,8 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
 				 struct page **compressed_pages,
 				 unsigned int nr_pages,
 				 unsigned int write_flags,
-				 struct cgroup_subsys_state *blkcg_css)
+				 struct cgroup_subsys_state *blkcg_css,
+				 bool writeback)
 {
 	struct btrfs_fs_info *fs_info = inode->root->fs_info;
 	struct bio *bio = NULL;
@@ -415,6 +417,7 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
 	cb->mirror_num = 0;
 	cb->compressed_pages = compressed_pages;
 	cb->compressed_len = compressed_len;
+	cb->writeback = writeback;
 	cb->orig_bio = NULL;
 	cb->nr_pages = nr_pages;
 
diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h
index 399be0b435bf..2ba9402f308d 100644
--- a/fs/btrfs/compression.h
+++ b/fs/btrfs/compression.h
@@ -52,6 +52,9 @@ struct compressed_bio {
 	/* The compression algorithm for this bio */
 	u8 compress_type;
 
+	/* Whether this is a write for writeback. */
+	bool writeback;
+
 	/* IO errors */
 	u8 errors;
 	int mirror_num;
@@ -95,7 +98,8 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
 				  struct page **compressed_pages,
 				  unsigned int nr_pages,
 				  unsigned int write_flags,
-				  struct cgroup_subsys_state *blkcg_css);
+				  struct cgroup_subsys_state *blkcg_css,
+				  bool writeback);
 blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
 				 int mirror_num, unsigned long bio_flags);
 
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index b68d8ea42f6e..960902caed97 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3222,6 +3222,8 @@ void btrfs_writepage_endio_finish_ordered(struct btrfs_inode *inode,
 struct btrfs_ioctl_encoded_io_args;
 ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter,
 			   struct btrfs_ioctl_encoded_io_args *encoded);
+ssize_t btrfs_do_encoded_write(struct kiocb *iocb, struct iov_iter *from,
+			     const struct btrfs_ioctl_encoded_io_args *encoded);
 
 extern const struct dentry_operations btrfs_dentry_operations;
 extern const struct iomap_ops btrfs_dio_iomap_ops;
@@ -3282,6 +3284,8 @@ int btrfs_replace_file_extents(struct btrfs_inode *inode,
 			   struct btrfs_trans_handle **trans_out);
 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
 			      struct btrfs_inode *inode, u64 start, u64 end);
+ssize_t btrfs_do_write_iter(struct kiocb *iocb, struct iov_iter *from,
+			    const struct btrfs_ioctl_encoded_io_args *encoded);
 int btrfs_release_file(struct inode *inode, struct file *file);
 int btrfs_dirty_pages(struct btrfs_inode *inode, struct page **pages,
 		      size_t num_pages, loff_t pos, size_t write_bytes,
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 6f9cb8baffd2..2b49cdcebd57 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2001,12 +2001,43 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
 	return written ? written : err;
 }
 
-static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
-				    struct iov_iter *from)
+static ssize_t btrfs_encoded_write(struct kiocb *iocb, struct iov_iter *from,
+			const struct btrfs_ioctl_encoded_io_args *encoded)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file_inode(file);
+	loff_t count;
+	ssize_t ret;
+
+	btrfs_inode_lock(inode, 0);
+	count = encoded->len;
+	ret = __generic_write_checks(iocb, &count);
+	if (ret == 0 && count != encoded->len) {
+		/*
+		 * The write got truncated by __generic_write_checks(). We can't
+		 * do a partial encoded write.
+		 */
+		ret = -EFBIG;
+	}
+	if (ret || encoded->len == 0)
+		goto out;
+
+	ret = btrfs_write_check(iocb, from, encoded->len);
+	if (ret < 0)
+		goto out;
+
+	ret = btrfs_do_encoded_write(iocb, from, encoded);
+out:
+	btrfs_inode_unlock(inode, 0);
+	return ret;
+}
+
+ssize_t btrfs_do_write_iter(struct kiocb *iocb, struct iov_iter *from,
+			    const struct btrfs_ioctl_encoded_io_args *encoded)
 {
 	struct file *file = iocb->ki_filp;
 	struct btrfs_inode *inode = BTRFS_I(file_inode(file));
-	ssize_t num_written = 0;
+	ssize_t num_written, num_sync;
 	const bool sync = iocb->ki_flags & IOCB_DSYNC;
 
 	/*
@@ -2017,22 +2048,28 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
 	if (test_bit(BTRFS_FS_STATE_ERROR, &inode->root->fs_info->fs_state))
 		return -EROFS;
 
-	if (!(iocb->ki_flags & IOCB_DIRECT) &&
-	    (iocb->ki_flags & IOCB_NOWAIT))
+	if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
 		return -EOPNOTSUPP;
 
 	if (sync)
 		atomic_inc(&inode->sync_writers);
 
-	if (iocb->ki_flags & IOCB_DIRECT)
-		num_written = btrfs_direct_write(iocb, from);
-	else
-		num_written = btrfs_buffered_write(iocb, from);
+	if (encoded) {
+		num_written = btrfs_encoded_write(iocb, from, encoded);
+		num_sync = encoded->len;
+	} else if (iocb->ki_flags & IOCB_DIRECT) {
+		num_written = num_sync = btrfs_direct_write(iocb, from);
+	} else {
+		num_written = num_sync = btrfs_buffered_write(iocb, from);
+	}
 
 	btrfs_set_inode_last_sub_trans(inode);
 
-	if (num_written > 0)
-		num_written = generic_write_sync(iocb, num_written);
+	if (num_sync > 0) {
+		num_sync = generic_write_sync(iocb, num_sync);
+		if (num_sync < 0)
+			num_written = num_sync;
+	}
 
 	if (sync)
 		atomic_dec(&inode->sync_writers);
@@ -2041,6 +2078,12 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
 	return num_written;
 }
 
+static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
+				    struct iov_iter *from)
+{
+	return btrfs_do_write_iter(iocb, from, NULL);
+}
+
 int btrfs_release_file(struct inode *inode, struct file *filp)
 {
 	struct btrfs_file_private *private = filp->private_data;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 6d7fae859fb5..c93ea5b3a2d0 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -966,7 +966,7 @@ static noinline void submit_compressed_extents(struct async_chunk *async_chunk)
 				    ins.offset, async_extent->pages,
 				    async_extent->nr_pages,
 				    async_chunk->write_flags,
-				    async_chunk->blkcg_css)) {
+				    async_chunk->blkcg_css, true)) {
 			struct page *p = async_extent->pages[0];
 			const u64 start = async_extent->start;
 			const u64 end = start + async_extent->ram_size - 1;
@@ -2967,6 +2967,7 @@ static int insert_ordered_extent_file_extent(struct btrfs_trans_handle *trans,
 	 * except if the ordered extent was truncated.
 	 */
 	update_inode_bytes = test_bit(BTRFS_ORDERED_DIRECT, &oe->flags) ||
+			     test_bit(BTRFS_ORDERED_ENCODED, &oe->flags) ||
 			     test_bit(BTRFS_ORDERED_TRUNCATED, &oe->flags);
 
 	return insert_reserved_file_extent(trans, BTRFS_I(oe->inode),
@@ -3001,7 +3002,8 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
 
 	if (!test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
 	    !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags) &&
-	    !test_bit(BTRFS_ORDERED_DIRECT, &ordered_extent->flags))
+	    !test_bit(BTRFS_ORDERED_DIRECT, &ordered_extent->flags) &&
+	    !test_bit(BTRFS_ORDERED_ENCODED, &ordered_extent->flags))
 		clear_bits |= EXTENT_DELALLOC_NEW;
 
 	freespace_inode = btrfs_is_free_space_inode(inode);
@@ -10985,6 +10987,256 @@ ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter,
 	return ret;
 }
 
+ssize_t btrfs_do_encoded_write(struct kiocb *iocb, struct iov_iter *from,
+			      const struct btrfs_ioctl_encoded_io_args *encoded)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+	struct extent_changeset *data_reserved = NULL;
+	struct extent_state *cached_state = NULL;
+	int compression;
+	size_t orig_count;
+	u64 start, end;
+	u64 num_bytes, ram_bytes, disk_num_bytes;
+	unsigned long nr_pages, i;
+	struct page **pages;
+	struct btrfs_key ins;
+	bool extent_reserved = false;
+	struct extent_map *em;
+	ssize_t ret;
+
+	switch (encoded->compression) {
+	case BTRFS_ENCODED_IO_COMPRESSION_ZLIB:
+		compression = BTRFS_COMPRESS_ZLIB;
+		break;
+	case BTRFS_ENCODED_IO_COMPRESSION_ZSTD:
+		compression = BTRFS_COMPRESS_ZSTD;
+		break;
+	case BTRFS_ENCODED_IO_COMPRESSION_LZO_4K:
+	case BTRFS_ENCODED_IO_COMPRESSION_LZO_8K:
+	case BTRFS_ENCODED_IO_COMPRESSION_LZO_16K:
+	case BTRFS_ENCODED_IO_COMPRESSION_LZO_32K:
+	case BTRFS_ENCODED_IO_COMPRESSION_LZO_64K:
+		/* The page size must match for LZO. */
+		if (encoded->compression -
+		    BTRFS_ENCODED_IO_COMPRESSION_LZO_4K + 12 != PAGE_SHIFT)
+			return -EINVAL;
+		compression = BTRFS_COMPRESS_LZO;
+		break;
+	default:
+		return -EINVAL;
+	}
+	if (encoded->encryption != BTRFS_ENCODED_IO_ENCRYPTION_NONE)
+		return -EINVAL;
+
+	orig_count = iov_iter_count(from);
+
+	/* The extent size must be sane. */
+	if (encoded->unencoded_len > BTRFS_MAX_UNCOMPRESSED ||
+	    orig_count > BTRFS_MAX_COMPRESSED || orig_count == 0)
+		return -EINVAL;
+
+	/*
+	 * The compressed data must be smaller than the decompressed data.
+	 *
+	 * It's of course possible for data to compress to larger or the same
+	 * size, but the buffered I/O path falls back to no compression for such
+	 * data, and we don't want to break any assumptions by creating these
+	 * extents.
+	 *
+	 * Note that this is less strict than the current check we have that the
+	 * compressed data must be at least one sector smaller than the
+	 * decompressed data. We only want to enforce the weaker requirement
+	 * from old kernels that it is at least one byte smaller.
+	 */
+	if (orig_count >= encoded->unencoded_len)
+		return -EINVAL;
+
+	/* The extent must start on a sector boundary. */
+	start = iocb->ki_pos;
+	if (!IS_ALIGNED(start, fs_info->sectorsize))
+		return -EINVAL;
+
+	/*
+	 * The extent must end on a sector boundary. However, we allow a write
+	 * which ends at or extends i_size to have an unaligned length; we round
+	 * up the extent size and set i_size to the unaligned end.
+	 */
+	if (start + encoded->len < inode->i_size &&
+	    !IS_ALIGNED(start + encoded->len, fs_info->sectorsize))
+		return -EINVAL;
+
+	/* Finally, the offset in the unencoded data must be sector-aligned. */
+	if (!IS_ALIGNED(encoded->unencoded_offset, fs_info->sectorsize))
+		return -EINVAL;
+
+	num_bytes = ALIGN(encoded->len, fs_info->sectorsize);
+	ram_bytes = ALIGN(encoded->unencoded_len, fs_info->sectorsize);
+	end = start + num_bytes - 1;
+
+	/*
+	 * If the extent cannot be inline, the compressed data on disk must be
+	 * sector-aligned. For convenience, we extend it with zeroes if it
+	 * isn't.
+	 */
+	disk_num_bytes = ALIGN(orig_count, fs_info->sectorsize);
+	nr_pages = DIV_ROUND_UP(disk_num_bytes, PAGE_SIZE);
+	pages = kvcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL_ACCOUNT);
+	if (!pages)
+		return -ENOMEM;
+	for (i = 0; i < nr_pages; i++) {
+		size_t bytes = min_t(size_t, PAGE_SIZE, iov_iter_count(from));
+		char *kaddr;
+
+		pages[i] = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_HIGHMEM);
+		if (!pages[i]) {
+			ret = -ENOMEM;
+			goto out_pages;
+		}
+		kaddr = kmap(pages[i]);
+		if (copy_from_iter(kaddr, bytes, from) != bytes) {
+			kunmap(pages[i]);
+			ret = -EFAULT;
+			goto out_pages;
+		}
+		if (bytes < PAGE_SIZE)
+			memset(kaddr + bytes, 0, PAGE_SIZE - bytes);
+		kunmap(pages[i]);
+	}
+
+	for (;;) {
+		struct btrfs_ordered_extent *ordered;
+
+		ret = btrfs_wait_ordered_range(inode, start, num_bytes);
+		if (ret)
+			goto out_pages;
+		ret = invalidate_inode_pages2_range(inode->i_mapping,
+						    start >> PAGE_SHIFT,
+						    end >> PAGE_SHIFT);
+		if (ret)
+			goto out_pages;
+		lock_extent_bits(io_tree, start, end, &cached_state);
+		ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
+						     num_bytes);
+		if (!ordered &&
+		    !filemap_range_has_page(inode->i_mapping, start, end))
+			break;
+		if (ordered)
+			btrfs_put_ordered_extent(ordered);
+		unlock_extent_cached(io_tree, start, end, &cached_state);
+		cond_resched();
+	}
+
+	/*
+	 * We don't use the higher-level delalloc space functions because our
+	 * num_bytes and disk_num_bytes are different.
+	 */
+	ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode), disk_num_bytes);
+	if (ret)
+		goto out_unlock;
+	ret = btrfs_qgroup_reserve_data(BTRFS_I(inode), &data_reserved, start,
+					num_bytes);
+	if (ret)
+		goto out_free_data_space;
+	ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), num_bytes,
+					      disk_num_bytes);
+	if (ret)
+		goto out_qgroup_free_data;
+
+	/* Try an inline extent first. */
+	if (start == 0 && encoded->unencoded_len == encoded->len &&
+	    encoded->unencoded_offset == 0) {
+		ret = cow_file_range_inline(BTRFS_I(inode), encoded->len,
+					    orig_count, compression, pages,
+					    true);
+		if (ret <= 0) {
+			if (ret == 0)
+				ret = orig_count;
+			goto out_delalloc_release;
+		}
+	}
+
+	ret = btrfs_reserve_extent(root, disk_num_bytes, disk_num_bytes,
+				   disk_num_bytes, 0, 0, &ins, 1, 1);
+	if (ret)
+		goto out_delalloc_release;
+	extent_reserved = true;
+
+	em = create_io_em(BTRFS_I(inode), start, num_bytes,
+			  start - encoded->unencoded_offset, ins.objectid,
+			  ins.offset, ins.offset, ram_bytes, compression,
+			  BTRFS_ORDERED_COMPRESSED);
+	if (IS_ERR(em)) {
+		ret = PTR_ERR(em);
+		goto out_free_reserved;
+	}
+	free_extent_map(em);
+
+	ret = btrfs_add_ordered_extent(BTRFS_I(inode), start, num_bytes,
+				       ram_bytes, ins.objectid, ins.offset,
+				       encoded->unencoded_offset,
+				       (1 << BTRFS_ORDERED_ENCODED) |
+				       (1 << BTRFS_ORDERED_COMPRESSED),
+				       compression);
+	if (ret) {
+		btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
+		goto out_free_reserved;
+	}
+	btrfs_dec_block_group_reservations(fs_info, ins.objectid);
+
+	if (start + encoded->len > inode->i_size)
+		i_size_write(inode, start + encoded->len);
+
+	unlock_extent_cached(io_tree, start, end, &cached_state);
+
+	btrfs_delalloc_release_extents(BTRFS_I(inode), num_bytes);
+
+	if (btrfs_submit_compressed_write(BTRFS_I(inode), start, num_bytes,
+					  ins.objectid, ins.offset, pages,
+					  nr_pages, 0, NULL, false)) {
+		btrfs_writepage_endio_finish_ordered(BTRFS_I(inode), pages[0],
+						     start, end, 0);
+		ret = -EIO;
+		goto out_pages;
+	}
+	ret = orig_count;
+	goto out;
+
+out_free_reserved:
+	btrfs_dec_block_group_reservations(fs_info, ins.objectid);
+	btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 1);
+out_delalloc_release:
+	btrfs_delalloc_release_extents(BTRFS_I(inode), num_bytes);
+	btrfs_delalloc_release_metadata(BTRFS_I(inode), disk_num_bytes,
+					ret < 0);
+out_qgroup_free_data:
+	if (ret < 0) {
+		btrfs_qgroup_free_data(BTRFS_I(inode), data_reserved, start,
+				       num_bytes);
+	}
+out_free_data_space:
+	/*
+	 * If btrfs_reserve_extent() succeeded, then we already decremented
+	 * bytes_may_use.
+	 */
+	if (!extent_reserved)
+		btrfs_free_reserved_data_space_noquota(fs_info, disk_num_bytes);
+out_unlock:
+	unlock_extent_cached(io_tree, start, end, &cached_state);
+out_pages:
+	for (i = 0; i < nr_pages; i++) {
+		if (pages[i])
+			__free_page(pages[i]);
+	}
+	kvfree(pages);
+out:
+	if (ret >= 0)
+		iocb->ki_pos += encoded->len;
+	return ret;
+}
+
 #ifdef CONFIG_SWAP
 /*
  * Add an entry indicating a block group or device which is pinned by a
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 7a0a9c752624..13a0a65c6a43 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -103,6 +103,8 @@ struct btrfs_ioctl_encoded_io_args_32 {
 
 #define BTRFS_IOC_ENCODED_READ_32 _IOR(BTRFS_IOCTL_MAGIC, 64, \
 				       struct btrfs_ioctl_encoded_io_args_32)
+#define BTRFS_IOC_ENCODED_WRITE_32 _IOW(BTRFS_IOCTL_MAGIC, 64, \
+					struct btrfs_ioctl_encoded_io_args_32)
 #endif
 
 /* Mask out flags that are inappropriate for the given type of inode. */
@@ -4992,6 +4994,102 @@ static int btrfs_ioctl_encoded_read(struct file *file, void __user *argp,
 	return ret;
 }
 
+static int btrfs_ioctl_encoded_write(struct file *file, void __user *argp,
+				     bool compat)
+{
+	struct btrfs_ioctl_encoded_io_args args;
+	struct iovec iovstack[UIO_FASTIOV];
+	struct iovec *iov = iovstack;
+	struct iov_iter iter;
+	loff_t pos;
+	struct kiocb kiocb;
+	ssize_t ret;
+
+	if (!capable(CAP_SYS_ADMIN)) {
+		ret = -EPERM;
+		goto out_acct;
+	}
+
+	if (!(file->f_mode & FMODE_WRITE)) {
+		ret = -EBADF;
+		goto out_acct;
+	}
+
+	if (compat) {
+#if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
+		struct btrfs_ioctl_encoded_io_args_32 args32;
+
+		if (copy_from_user(&args32, argp, sizeof(args32))) {
+			ret = -EFAULT;
+			goto out_acct;
+		}
+		args.iov = compat_ptr(args32.iov);
+		args.iovcnt = args.iovcnt;
+		memcpy(&args.offset, &args32.offset,
+		       sizeof(args) -
+		       offsetof(struct btrfs_ioctl_encoded_io_args, offset));
+#else
+		return -ENOTTY;
+#endif
+	} else {
+		if (copy_from_user(&args, argp, sizeof(args))) {
+			ret = -EFAULT;
+			goto out_acct;
+		}
+	}
+
+	ret = -EINVAL;
+	if (args.flags != 0)
+		goto out_acct;
+	if (memchr_inv(args.reserved, 0, sizeof(args.reserved)))
+		goto out_acct;
+	if (args.compression == BTRFS_ENCODED_IO_COMPRESSION_NONE &&
+	    args.encryption == BTRFS_ENCODED_IO_ENCRYPTION_NONE)
+		goto out_acct;
+	if (args.compression >= BTRFS_ENCODED_IO_COMPRESSION_TYPES ||
+	    args.encryption >= BTRFS_ENCODED_IO_ENCRYPTION_TYPES)
+		goto out_acct;
+	if (args.unencoded_offset > args.unencoded_len)
+		goto out_acct;
+	if (args.len > args.unencoded_len - args.unencoded_offset)
+		goto out_acct;
+
+	ret = import_iovec(WRITE, args.iov, args.iovcnt, ARRAY_SIZE(iovstack),
+			   &iov, &iter);
+	if (ret < 0)
+		goto out_acct;
+
+	file_start_write(file);
+
+	if (iov_iter_count(&iter) == 0) {
+		ret = 0;
+		goto out_end_write;
+	}
+	pos = args.offset;
+	ret = rw_verify_area(WRITE, file, &pos, args.len);
+	if (ret < 0)
+		goto out_end_write;
+
+	init_sync_kiocb(&kiocb, file);
+	ret = kiocb_set_rw_flags(&kiocb, 0);
+	if (ret)
+		goto out_end_write;
+	kiocb.ki_pos = pos;
+
+	ret = btrfs_do_write_iter(&kiocb, &iter, &args);
+	if (ret > 0)
+		fsnotify_modify(file);
+
+out_end_write:
+	file_end_write(file);
+	kfree(iov);
+out_acct:
+	if (ret > 0)
+		add_wchar(current, ret);
+	inc_syscw(current);
+	return ret;
+}
+
 long btrfs_ioctl(struct file *file, unsigned int
 		cmd, unsigned long arg)
 {
@@ -5138,9 +5236,13 @@ long btrfs_ioctl(struct file *file, unsigned int
 		return fsverity_ioctl_measure(file, argp);
 	case BTRFS_IOC_ENCODED_READ:
 		return btrfs_ioctl_encoded_read(file, argp, false);
+	case BTRFS_IOC_ENCODED_WRITE:
+		return btrfs_ioctl_encoded_write(file, argp, false);
 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
 	case BTRFS_IOC_ENCODED_READ_32:
 		return btrfs_ioctl_encoded_read(file, argp, true);
+	case BTRFS_IOC_ENCODED_WRITE_32:
+		return btrfs_ioctl_encoded_write(file, argp, true);
 #endif
 	}
 
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index 550c34fa0e6d..180f302dee93 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -521,9 +521,15 @@ void btrfs_remove_ordered_extent(struct btrfs_inode *btrfs_inode,
 	spin_lock(&btrfs_inode->lock);
 	btrfs_mod_outstanding_extents(btrfs_inode, -1);
 	spin_unlock(&btrfs_inode->lock);
-	if (root != fs_info->tree_root)
-		btrfs_delalloc_release_metadata(btrfs_inode, entry->num_bytes,
-						false);
+	if (root != fs_info->tree_root) {
+		u64 release;
+
+		if (test_bit(BTRFS_ORDERED_ENCODED, &entry->flags))
+			release = entry->disk_num_bytes;
+		else
+			release = entry->num_bytes;
+		btrfs_delalloc_release_metadata(btrfs_inode, release, false);
+	}
 
 	percpu_counter_add_batch(&fs_info->ordered_bytes, -entry->num_bytes,
 				 fs_info->delalloc_batch);
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index 0feb0c29839e..04588ccad34c 100644
--- a/fs/btrfs/ordered-data.h
+++ b/fs/btrfs/ordered-data.h
@@ -74,6 +74,8 @@ enum {
 	BTRFS_ORDERED_LOGGED_CSUM,
 	/* We wait for this extent to complete in the current transaction */
 	BTRFS_ORDERED_PENDING,
+	/* RWF_ENCODED I/O */
+	BTRFS_ORDERED_ENCODED,
 };
 
 /* BTRFS_ORDERED_* flags that specify the type of the extent. */
@@ -81,7 +83,8 @@ enum {
 				  (1UL << BTRFS_ORDERED_NOCOW) |	\
 				  (1UL << BTRFS_ORDERED_PREALLOC) |	\
 				  (1UL << BTRFS_ORDERED_COMPRESSED) |	\
-				  (1UL << BTRFS_ORDERED_DIRECT))
+				  (1UL << BTRFS_ORDERED_DIRECT) |	\
+				  (1UL << BTRFS_ORDERED_ENCODED))
 
 struct btrfs_ordered_extent {
 	/* logical offset in the file */
-- 
2.32.0

[PATCH v10 10/14] btrfs: add send stream v2 definitions

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

This adds the definitions of the new commands for send stream version 2
and their respective attributes: fallocate, FS_IOC_SETFLAGS (a.k.a.
chattr), and encoded writes. It also documents two changes to the send
stream format in v2: the receiver shouldn't assume a maximum command
size, and the DATA attribute is encoded differently to allow for writes
larger than 64k. These will be implemented in subsequent changes, and
then the ioctl will accept the new flags.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 fs/btrfs/send.c            |  2 +-
 fs/btrfs/send.h            | 30 +++++++++++++++++++++++++++++-
 include/uapi/linux/btrfs.h | 13 +++++++++++++
 3 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 72f9b865e847..02ac158837ce 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -7294,7 +7294,7 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
 
 	sctx->clone_roots_cnt = arg->clone_sources_count;
 
-	sctx->send_max_size = BTRFS_SEND_BUF_SIZE;
+	sctx->send_max_size = BTRFS_SEND_BUF_SIZE_V1;
 	sctx->send_buf = kvmalloc(sctx->send_max_size, GFP_KERNEL);
 	if (!sctx->send_buf) {
 		ret = -ENOMEM;
diff --git a/fs/btrfs/send.h b/fs/btrfs/send.h
index de91488b7cd0..9f4f7b96b1eb 100644
--- a/fs/btrfs/send.h
+++ b/fs/btrfs/send.h
@@ -12,7 +12,11 @@
 #define BTRFS_SEND_STREAM_MAGIC "btrfs-stream"
 #define BTRFS_SEND_STREAM_VERSION 1
 
-#define BTRFS_SEND_BUF_SIZE SZ_64K
+/*
+ * In send stream v1, no command is larger than 64k. In send stream v2, no limit
+ * should be assumed.
+ */
+#define BTRFS_SEND_BUF_SIZE_V1 SZ_64K
 
 enum btrfs_tlv_type {
 	BTRFS_TLV_U8,
@@ -76,6 +80,13 @@ enum btrfs_send_cmd {
 
 	BTRFS_SEND_C_END,
 	BTRFS_SEND_C_UPDATE_EXTENT,
+
+	/* The following commands were added in send stream v2. */
+
+	BTRFS_SEND_C_FALLOCATE,
+	BTRFS_SEND_C_SETFLAGS,
+	BTRFS_SEND_C_ENCODED_WRITE,
+
 	__BTRFS_SEND_C_MAX,
 };
 #define BTRFS_SEND_C_MAX (__BTRFS_SEND_C_MAX - 1)
@@ -106,6 +117,11 @@ enum {
 	BTRFS_SEND_A_PATH_LINK,
 
 	BTRFS_SEND_A_FILE_OFFSET,
+	/*
+	 * In send stream v2, this attribute is special: it must be the last
+	 * attribute in a command, its header contains only the type, and its
+	 * length is implicitly the remaining length of the command.
+	 */
 	BTRFS_SEND_A_DATA,
 
 	BTRFS_SEND_A_CLONE_UUID,
@@ -114,6 +130,18 @@ enum {
 	BTRFS_SEND_A_CLONE_OFFSET,
 	BTRFS_SEND_A_CLONE_LEN,
 
+	/* The following attributes were added in send stream v2. */
+
+	BTRFS_SEND_A_FALLOCATE_MODE,
+
+	BTRFS_SEND_A_SETFLAGS_FLAGS,
+
+	BTRFS_SEND_A_UNENCODED_FILE_LEN,
+	BTRFS_SEND_A_UNENCODED_LEN,
+	BTRFS_SEND_A_UNENCODED_OFFSET,
+	BTRFS_SEND_A_COMPRESSION,
+	BTRFS_SEND_A_ENCRYPTION,
+
 	__BTRFS_SEND_A_MAX,
 };
 #define BTRFS_SEND_A_MAX (__BTRFS_SEND_A_MAX - 1)
diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index 95da52955894..4f875f355e83 100644
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -771,6 +771,19 @@ struct btrfs_ioctl_received_subvol_args {
  */
 #define BTRFS_SEND_FLAG_OMIT_END_CMD		0x4
 
+/*
+ * Use version 2 of the send stream, which adds new commands and supports larger
+ * writes.
+ */
+#define BTRFS_SEND_FLAG_STREAM_V2		0x8
+
+/*
+ * Send compressed data using the ENCODED_WRITE command instead of decompressing
+ * the data and sending it with the WRITE command. This requires
+ * BTRFS_SEND_FLAG_STREAM_V2.
+ */
+#define BTRFS_SEND_FLAG_COMPRESSED		0x10
+
 #define BTRFS_SEND_FLAG_MASK \
 	(BTRFS_SEND_FLAG_NO_FILE_DATA | \
 	 BTRFS_SEND_FLAG_OMIT_STREAM_HEADER | \
-- 
2.32.0

[PATCH v10 11/14] btrfs: send: write larger chunks when using stream v2

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

The length field of the send stream TLV header is 16 bits. This means
that the maximum amount of data that can be sent for one write is 64k
minus one. However, encoded writes must be able to send the maximum
compressed extent (128k) in one command. To support this, send stream
version 2 encodes the DATA attribute differently: it has no length
field, and the length is implicitly up to the end of containing command
(which has a 32-bit length field). Although this is necessary for
encoded writes, normal writes can benefit from it, too.

For v2, let's bump up the send buffer to the maximum compressed extent
size plus 16k for the other metadata (144k total). Since this will most
likely be vmalloc'd (and always will be after the next commit), we round
it up to the next page since we might as well use the rest of the page
on systems with >16k pages.

Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 fs/btrfs/send.c | 34 ++++++++++++++++++++++++++--------
 1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 02ac158837ce..dfe598d12b8c 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -4915,14 +4915,27 @@ static inline u64 max_send_read_size(const struct send_ctx *sctx)
 
 static int put_data_header(struct send_ctx *sctx, u32 len)
 {
-	struct btrfs_tlv_header *hdr;
+	if (sctx->flags & BTRFS_SEND_FLAG_STREAM_V2) {
+		/*
+		 * In v2, the data attribute header doesn't include a length; it
+		 * is implicitly to the end of the command.
+		 */
+		if (sctx->send_max_size - sctx->send_size < 2 + len)
+			return -EOVERFLOW;
+		put_unaligned_le16(BTRFS_SEND_A_DATA,
+				   sctx->send_buf + sctx->send_size);
+		sctx->send_size += 2;
+	} else {
+		struct btrfs_tlv_header *hdr;
 
-	if (sctx->send_max_size - sctx->send_size < sizeof(*hdr) + len)
-		return -EOVERFLOW;
-	hdr = (struct btrfs_tlv_header *)(sctx->send_buf + sctx->send_size);
-	put_unaligned_le16(BTRFS_SEND_A_DATA, &hdr->tlv_type);
-	put_unaligned_le16(len, &hdr->tlv_len);
-	sctx->send_size += sizeof(*hdr);
+		if (sctx->send_max_size - sctx->send_size < sizeof(*hdr) + len)
+			return -EOVERFLOW;
+		hdr = (struct btrfs_tlv_header *)(sctx->send_buf +
+						  sctx->send_size);
+		put_unaligned_le16(BTRFS_SEND_A_DATA, &hdr->tlv_type);
+		put_unaligned_le16(len, &hdr->tlv_len);
+		sctx->send_size += sizeof(*hdr);
+	}
 	return 0;
 }
 
@@ -7294,7 +7307,12 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
 
 	sctx->clone_roots_cnt = arg->clone_sources_count;
 
-	sctx->send_max_size = BTRFS_SEND_BUF_SIZE_V1;
+	if (sctx->flags & BTRFS_SEND_FLAG_STREAM_V2) {
+		sctx->send_max_size = ALIGN(SZ_16K + BTRFS_MAX_COMPRESSED,
+					    PAGE_SIZE);
+	} else {
+		sctx->send_max_size = BTRFS_SEND_BUF_SIZE_V1;
+	}
 	sctx->send_buf = kvmalloc(sctx->send_max_size, GFP_KERNEL);
 	if (!sctx->send_buf) {
 		ret = -ENOMEM;
-- 
2.32.0

[PATCH v10 12/14] btrfs: send: allocate send buffer with alloc_page() and vmap() for v2

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

For encoded writes, we need the raw pages for reading compressed data
directly via a bio. So, replace kvmalloc() with vmap() so we have access
to the raw pages. 144k is large enough that it usually gets allocated
with vmalloc(), anyways.

Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 fs/btrfs/send.c | 33 +++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index dfe598d12b8c..7242362ecb23 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -81,6 +81,7 @@ struct send_ctx {
 	char *send_buf;
 	u32 send_size;
 	u32 send_max_size;
+	struct page **send_buf_pages;
 	u64 total_send_size;
 	u64 cmd_send_size[BTRFS_SEND_C_MAX + 1];
 	u64 flags;	/* 'flags' member of btrfs_ioctl_send_args is u64 */
@@ -7230,6 +7231,7 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
 	struct btrfs_root *clone_root;
 	struct send_ctx *sctx = NULL;
 	u32 i;
+	u32 send_buf_num_pages = 0;
 	u64 *clone_sources_tmp = NULL;
 	int clone_sources_to_rollback = 0;
 	size_t alloc_size;
@@ -7310,10 +7312,28 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
 	if (sctx->flags & BTRFS_SEND_FLAG_STREAM_V2) {
 		sctx->send_max_size = ALIGN(SZ_16K + BTRFS_MAX_COMPRESSED,
 					    PAGE_SIZE);
+		send_buf_num_pages = sctx->send_max_size >> PAGE_SHIFT;
+		sctx->send_buf_pages = kcalloc(send_buf_num_pages,
+					       sizeof(*sctx->send_buf_pages),
+					       GFP_KERNEL);
+		if (!sctx->send_buf_pages) {
+			send_buf_num_pages = 0;
+			ret = -ENOMEM;
+			goto out;
+		}
+		for (i = 0; i < send_buf_num_pages; i++) {
+			sctx->send_buf_pages[i] = alloc_page(GFP_KERNEL);
+			if (!sctx->send_buf_pages[i]) {
+				ret = -ENOMEM;
+				goto out;
+			}
+		}
+		sctx->send_buf = vmap(sctx->send_buf_pages, send_buf_num_pages,
+				      VM_MAP, PAGE_KERNEL);
 	} else {
 		sctx->send_max_size = BTRFS_SEND_BUF_SIZE_V1;
+		sctx->send_buf = kvmalloc(sctx->send_max_size, GFP_KERNEL);
 	}
-	sctx->send_buf = kvmalloc(sctx->send_max_size, GFP_KERNEL);
 	if (!sctx->send_buf) {
 		ret = -ENOMEM;
 		goto out;
@@ -7520,7 +7540,16 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
 			fput(sctx->send_filp);
 
 		kvfree(sctx->clone_roots);
-		kvfree(sctx->send_buf);
+		if (sctx->flags & BTRFS_SEND_FLAG_STREAM_V2) {
+			vunmap(sctx->send_buf);
+			for (i = 0; i < send_buf_num_pages; i++) {
+				if (sctx->send_buf_pages[i])
+					__free_page(sctx->send_buf_pages[i]);
+			}
+			kfree(sctx->send_buf_pages);
+		} else {
+			kvfree(sctx->send_buf);
+		}
 
 		name_cache_free(sctx);
 
-- 
2.32.0

[PATCH v10 13/14] btrfs: send: send compressed extents with encoded writes

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

Now that all of the pieces are in place, we can use the ENCODED_WRITE
command to send compressed extents when appropriate.

Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 fs/btrfs/ctree.h |   4 +
 fs/btrfs/inode.c |   6 +-
 fs/btrfs/send.c  | 230 +++++++++++++++++++++++++++++++++++++++++++----
 3 files changed, 220 insertions(+), 20 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 960902caed97..a61b447044a9 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3219,6 +3219,10 @@ int btrfs_writepage_cow_fixup(struct page *page);
 void btrfs_writepage_endio_finish_ordered(struct btrfs_inode *inode,
 					  struct page *page, u64 start,
 					  u64 end, bool uptodate);
+int btrfs_encoded_io_compression_from_extent(int compress_type);
+int btrfs_encoded_read_regular_fill_pages(struct inode *inode, u64 offset,
+					  u64 disk_io_size,
+					  struct page **pages);
 struct btrfs_ioctl_encoded_io_args;
 ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter,
 			   struct btrfs_ioctl_encoded_io_args *encoded);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index c93ea5b3a2d0..4fcb3f9b6bf1 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -10498,7 +10498,7 @@ void btrfs_set_range_writeback(struct btrfs_inode *inode, u64 start, u64 end)
 	}
 }
 
-static int btrfs_encoded_io_compression_from_extent(int compress_type)
+int btrfs_encoded_io_compression_from_extent(int compress_type)
 {
 	switch (compress_type) {
 	case BTRFS_COMPRESS_NONE:
@@ -10701,8 +10701,8 @@ static void btrfs_encoded_read_endio(struct bio *bio)
 	bio_put(bio);
 }
 
-static int btrfs_encoded_read_regular_fill_pages(struct inode *inode, u64 offset,
-						 u64 disk_io_size, struct page **pages)
+int btrfs_encoded_read_regular_fill_pages(struct inode *inode, u64 offset,
+					  u64 disk_io_size, struct page **pages)
 {
 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 	struct btrfs_encoded_read_private priv = {
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 7242362ecb23..363a69125023 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -595,6 +595,7 @@ static int tlv_put(struct send_ctx *sctx, u16 attr, const void *data, int len)
 		return tlv_put(sctx, attr, &__tmp, sizeof(__tmp));	\
 	}
 
+TLV_PUT_DEFINE_INT(32)
 TLV_PUT_DEFINE_INT(64)
 
 static int tlv_put_string(struct send_ctx *sctx, u16 attr,
@@ -5210,16 +5211,211 @@ static int send_hole(struct send_ctx *sctx, u64 end)
 	return ret;
 }
 
-static int send_extent_data(struct send_ctx *sctx,
-			    const u64 offset,
-			    const u64 len)
+static int send_encoded_inline_extent(struct send_ctx *sctx,
+				      struct btrfs_path *path, u64 offset,
+				      u64 len)
 {
+	struct btrfs_root *root = sctx->send_root;
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct inode *inode;
+	struct fs_path *p;
+	struct extent_buffer *leaf = path->nodes[0];
+	struct btrfs_key key;
+	struct btrfs_file_extent_item *ei;
+	u64 ram_bytes;
+	size_t inline_size;
+	int ret;
+
+	inode = btrfs_iget(fs_info->sb, sctx->cur_ino, root);
+	if (IS_ERR(inode))
+		return PTR_ERR(inode);
+
+	p = fs_path_alloc();
+	if (!p) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ret = begin_cmd(sctx, BTRFS_SEND_C_ENCODED_WRITE);
+	if (ret < 0)
+		goto out;
+
+	ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
+	if (ret < 0)
+		goto out;
+
+	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+	ei = btrfs_item_ptr(leaf, path->slots[0],
+			    struct btrfs_file_extent_item);
+	ram_bytes = btrfs_file_extent_ram_bytes(leaf, ei);
+	inline_size = btrfs_file_extent_inline_item_len(leaf,
+						btrfs_item_nr(path->slots[0]));
+
+	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
+	TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
+	TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_FILE_LEN,
+		    min(key.offset + ram_bytes - offset, len));
+	TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_LEN, ram_bytes);
+	TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_OFFSET, offset - key.offset);
+	ret = btrfs_encoded_io_compression_from_extent(
+				btrfs_file_extent_compression(leaf, ei));
+	if (ret < 0)
+		goto out;
+	TLV_PUT_U32(sctx, BTRFS_SEND_A_COMPRESSION, ret);
+	TLV_PUT_U32(sctx, BTRFS_SEND_A_ENCRYPTION, 0);
+
+	ret = put_data_header(sctx, inline_size);
+	if (ret < 0)
+		goto out;
+	read_extent_buffer(leaf, sctx->send_buf + sctx->send_size,
+			   btrfs_file_extent_inline_start(ei), inline_size);
+	sctx->send_size += inline_size;
+
+	ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+	fs_path_free(p);
+	iput(inode);
+	return ret;
+}
+
+static int send_encoded_extent(struct send_ctx *sctx, struct btrfs_path *path,
+			       u64 offset, u64 len)
+{
+	struct btrfs_root *root = sctx->send_root;
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct inode *inode;
+	struct fs_path *p;
+	struct extent_buffer *leaf = path->nodes[0];
+	struct btrfs_key key;
+	struct btrfs_file_extent_item *ei;
+	u64 block_start;
+	u64 block_len;
+	u32 data_offset;
+	struct btrfs_cmd_header *hdr;
+	u32 crc;
+	int ret;
+
+	inode = btrfs_iget(fs_info->sb, sctx->cur_ino, root);
+	if (IS_ERR(inode))
+		return PTR_ERR(inode);
+
+	p = fs_path_alloc();
+	if (!p) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ret = begin_cmd(sctx, BTRFS_SEND_C_ENCODED_WRITE);
+	if (ret < 0)
+		goto out;
+
+	ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
+	if (ret < 0)
+		goto out;
+
+	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+	ei = btrfs_item_ptr(leaf, path->slots[0],
+			    struct btrfs_file_extent_item);
+	block_start = btrfs_file_extent_disk_bytenr(leaf, ei);
+	block_len = btrfs_file_extent_disk_num_bytes(leaf, ei);
+
+	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
+	TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
+	TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_FILE_LEN,
+		    min(key.offset + btrfs_file_extent_num_bytes(leaf, ei) - offset,
+			len));
+	TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_LEN,
+		    btrfs_file_extent_ram_bytes(leaf, ei));
+	TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_OFFSET,
+		    offset - key.offset + btrfs_file_extent_offset(leaf, ei));
+	ret = btrfs_encoded_io_compression_from_extent(
+				btrfs_file_extent_compression(leaf, ei));
+	if (ret < 0)
+		goto out;
+	TLV_PUT_U32(sctx, BTRFS_SEND_A_COMPRESSION, ret);
+	TLV_PUT_U32(sctx, BTRFS_SEND_A_ENCRYPTION, 0);
+
+	ret = put_data_header(sctx, block_len);
+	if (ret < 0)
+		goto out;
+
+	data_offset = ALIGN(sctx->send_size, PAGE_SIZE);
+	if (data_offset > sctx->send_max_size ||
+	    sctx->send_max_size - data_offset < block_len) {
+		ret = -EOVERFLOW;
+		goto out;
+	}
+
+	ret = btrfs_encoded_read_regular_fill_pages(inode, block_start,
+						    block_len,
+						    sctx->send_buf_pages +
+						    (data_offset >> PAGE_SHIFT));
+	if (ret)
+		goto out;
+
+	hdr = (struct btrfs_cmd_header *)sctx->send_buf;
+	hdr->len = cpu_to_le32(sctx->send_size + block_len - sizeof(*hdr));
+	hdr->crc = 0;
+	crc = btrfs_crc32c(0, sctx->send_buf, sctx->send_size);
+	crc = btrfs_crc32c(crc, sctx->send_buf + data_offset, block_len);
+	hdr->crc = cpu_to_le32(crc);
+
+	ret = write_buf(sctx->send_filp, sctx->send_buf, sctx->send_size,
+			&sctx->send_off);
+	if (!ret) {
+		ret = write_buf(sctx->send_filp, sctx->send_buf + data_offset,
+				block_len, &sctx->send_off);
+	}
+	sctx->total_send_size += sctx->send_size + block_len;
+	sctx->cmd_send_size[le16_to_cpu(hdr->cmd)] +=
+		sctx->send_size + block_len;
+	sctx->send_size = 0;
+
+tlv_put_failure:
+out:
+	fs_path_free(p);
+	iput(inode);
+	return ret;
+}
+
+static int send_extent_data(struct send_ctx *sctx, struct btrfs_path *path,
+			    const u64 offset, const u64 len)
+{
+	struct extent_buffer *leaf = path->nodes[0];
+	struct btrfs_file_extent_item *ei;
 	u64 read_size = max_send_read_size(sctx);
 	u64 sent = 0;
 
 	if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA)
 		return send_update_extent(sctx, offset, len);
 
+	ei = btrfs_item_ptr(leaf, path->slots[0],
+			    struct btrfs_file_extent_item);
+	if ((sctx->flags & BTRFS_SEND_FLAG_COMPRESSED) &&
+	    btrfs_file_extent_compression(leaf, ei) != BTRFS_COMPRESS_NONE) {
+		bool is_inline = (btrfs_file_extent_type(leaf, ei) ==
+				  BTRFS_FILE_EXTENT_INLINE);
+
+		/*
+		 * Send the compressed extent unless the compressed data is
+		 * larger than the decompressed data. This can happen if we're
+		 * not sending the entire extent, either because it has been
+		 * partially overwritten/truncated or because this is a part of
+		 * the extent that we couldn't clone in clone_range().
+		 */
+		if (is_inline &&
+		    btrfs_file_extent_inline_item_len(leaf,
+					btrfs_item_nr(path->slots[0])) <= len) {
+			return send_encoded_inline_extent(sctx, path, offset,
+							  len);
+		} else if (!is_inline &&
+			   btrfs_file_extent_disk_num_bytes(leaf, ei) <= len) {
+			return send_encoded_extent(sctx, path, offset, len);
+		}
+	}
+
 	while (sent < len) {
 		u64 size = min(len - sent, read_size);
 		int ret;
@@ -5290,12 +5486,9 @@ static int send_capabilities(struct send_ctx *sctx)
 	return ret;
 }
 
-static int clone_range(struct send_ctx *sctx,
-		       struct clone_root *clone_root,
-		       const u64 disk_byte,
-		       u64 data_offset,
-		       u64 offset,
-		       u64 len)
+static int clone_range(struct send_ctx *sctx, struct btrfs_path *dst_path,
+		       struct clone_root *clone_root, const u64 disk_byte,
+		       u64 data_offset, u64 offset, u64 len)
 {
 	struct btrfs_path *path;
 	struct btrfs_key key;
@@ -5319,7 +5512,7 @@ static int clone_range(struct send_ctx *sctx,
 	 */
 	if (clone_root->offset == 0 &&
 	    len == sctx->send_root->fs_info->sectorsize)
-		return send_extent_data(sctx, offset, len);
+		return send_extent_data(sctx, dst_path, offset, len);
 
 	path = alloc_path_for_send();
 	if (!path)
@@ -5416,7 +5609,8 @@ static int clone_range(struct send_ctx *sctx,
 
 			if (hole_len > len)
 				hole_len = len;
-			ret = send_extent_data(sctx, offset, hole_len);
+			ret = send_extent_data(sctx, dst_path, offset,
+					       hole_len);
 			if (ret < 0)
 				goto out;
 
@@ -5489,14 +5683,16 @@ static int clone_range(struct send_ctx *sctx,
 					if (ret < 0)
 						goto out;
 				}
-				ret = send_extent_data(sctx, offset + slen,
+				ret = send_extent_data(sctx, dst_path,
+						       offset + slen,
 						       clone_len - slen);
 			} else {
 				ret = send_clone(sctx, offset, clone_len,
 						 clone_root);
 			}
 		} else {
-			ret = send_extent_data(sctx, offset, clone_len);
+			ret = send_extent_data(sctx, dst_path, offset,
+					       clone_len);
 		}
 
 		if (ret < 0)
@@ -5528,7 +5724,7 @@ static int clone_range(struct send_ctx *sctx,
 	}
 
 	if (len > 0)
-		ret = send_extent_data(sctx, offset, len);
+		ret = send_extent_data(sctx, dst_path, offset, len);
 	else
 		ret = 0;
 out:
@@ -5559,10 +5755,10 @@ static int send_write_or_clone(struct send_ctx *sctx,
 				    struct btrfs_file_extent_item);
 		disk_byte = btrfs_file_extent_disk_bytenr(path->nodes[0], ei);
 		data_offset = btrfs_file_extent_offset(path->nodes[0], ei);
-		ret = clone_range(sctx, clone_root, disk_byte, data_offset,
-				  offset, end - offset);
+		ret = clone_range(sctx, path, clone_root, disk_byte,
+				  data_offset, offset, end - offset);
 	} else {
-		ret = send_extent_data(sctx, offset, end - offset);
+		ret = send_extent_data(sctx, path, offset, end - offset);
 	}
 	sctx->cur_inode_next_write_offset = end;
 	return ret;
-- 
2.32.0

[PATCH v10 14/14] btrfs: send: enable support for stream v2 and compressed writes

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

Now that the new support is implemented, allow the ioctl to accept the
flags and update the version in sysfs.

Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 fs/btrfs/send.c            | 10 +++++++++-
 fs/btrfs/send.h            |  2 +-
 include/uapi/linux/btrfs.h |  4 +++-
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 363a69125023..5b4a73d76991 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -671,7 +671,10 @@ static int send_header(struct send_ctx *sctx)
 	struct btrfs_stream_header hdr;
 
 	strcpy(hdr.magic, BTRFS_SEND_STREAM_MAGIC);
-	hdr.version = cpu_to_le32(BTRFS_SEND_STREAM_VERSION);
+	if (sctx->flags & BTRFS_SEND_FLAG_STREAM_V2)
+		hdr.version = cpu_to_le32(2);
+	else
+		hdr.version = cpu_to_le32(1);
 
 	return write_buf(sctx->send_filp, &hdr, sizeof(hdr),
 					&sctx->send_off);
@@ -7473,6 +7476,11 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
 		ret = -EINVAL;
 		goto out;
 	}
+	if ((arg->flags & BTRFS_SEND_FLAG_COMPRESSED) &&
+	    !(arg->flags & BTRFS_SEND_FLAG_STREAM_V2)) {
+		ret = -EINVAL;
+		goto out;
+	}
 
 	sctx = kzalloc(sizeof(struct send_ctx), GFP_KERNEL);
 	if (!sctx) {
diff --git a/fs/btrfs/send.h b/fs/btrfs/send.h
index 9f4f7b96b1eb..9c83e14a43b2 100644
--- a/fs/btrfs/send.h
+++ b/fs/btrfs/send.h
@@ -10,7 +10,7 @@
 #include "ctree.h"
 
 #define BTRFS_SEND_STREAM_MAGIC "btrfs-stream"
-#define BTRFS_SEND_STREAM_VERSION 1
+#define BTRFS_SEND_STREAM_VERSION 2
 
 /*
  * In send stream v1, no command is larger than 64k. In send stream v2, no limit
diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index 4f875f355e83..5c13e407982f 100644
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -787,7 +787,9 @@ struct btrfs_ioctl_received_subvol_args {
 #define BTRFS_SEND_FLAG_MASK \
 	(BTRFS_SEND_FLAG_NO_FILE_DATA | \
 	 BTRFS_SEND_FLAG_OMIT_STREAM_HEADER | \
-	 BTRFS_SEND_FLAG_OMIT_END_CMD)
+	 BTRFS_SEND_FLAG_OMIT_END_CMD | \
+	 BTRFS_SEND_FLAG_STREAM_V2 | \
+	 BTRFS_SEND_FLAG_COMPRESSED)
 
 struct btrfs_ioctl_send_args {
 	__s64 send_fd;			/* in */
-- 
2.32.0

[PATCH v10 01/10] btrfs-progs: receive: support v2 send stream larger tlv_len

[Omar Sandoval]

From: Boris Burkov <borisb@fb.com>

An encoded extent can be up to 128K in length, which exceeds the largest
value expressible by the current send stream format's 16 bit tlv_len
field. Since encoded writes cannot be split into multiple writes by
btrfs send, the send stream format must change to accommodate encoded
writes.

Supporting this changed format requires retooling how we store the
commands we have processed. Since we can no longer use btrfs_tlv_header
to describe every attribute, we define a new struct btrfs_send_attribute
which has a 32 bit length field, and use that to store the attribute
information needed for receive processing. This is transparent to users
of the various TLV_GET macros.

Signed-off-by: Boris Burkov <boris@bur.io>
---
 common/send-stream.c | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/common/send-stream.c b/common/send-stream.c
index a0c52f79..cd5aa311 100644
--- a/common/send-stream.c
+++ b/common/send-stream.c
@@ -24,13 +24,23 @@
 #include "crypto/crc32c.h"
 #include "common/utils.h"
 
+struct btrfs_send_attribute {
+	u16 tlv_type;
+	/*
+	 * Note: in btrfs_tlv_header, this is __le16, but we need 32 bits for
+	 * attributes with file data as of version 2 of the send stream format
+	 */
+	u32 tlv_len;
+	char *data;
+};
+
 struct btrfs_send_stream {
 	char read_buf[BTRFS_SEND_BUF_SIZE];
 	int fd;
 
 	int cmd;
 	struct btrfs_cmd_header *cmd_hdr;
-	struct btrfs_tlv_header *cmd_attrs[BTRFS_SEND_A_MAX + 1];
+	struct btrfs_send_attribute cmd_attrs[BTRFS_SEND_A_MAX + 1];
 	u32 version;
 
 	/*
@@ -152,6 +162,7 @@ static int read_cmd(struct btrfs_send_stream *sctx)
 		struct btrfs_tlv_header *tlv_hdr;
 		u16 tlv_type;
 		u16 tlv_len;
+		struct btrfs_send_attribute *send_attr;
 
 		tlv_hdr = (struct btrfs_tlv_header *)data;
 		tlv_type = le16_to_cpu(tlv_hdr->tlv_type);
@@ -164,10 +175,15 @@ static int read_cmd(struct btrfs_send_stream *sctx)
 			goto out;
 		}
 
-		sctx->cmd_attrs[tlv_type] = tlv_hdr;
+		send_attr = &sctx->cmd_attrs[tlv_type];
+		send_attr->tlv_type = tlv_type;
+		send_attr->tlv_len = tlv_len;
+		pos += sizeof(*tlv_hdr);
+		data += sizeof(*tlv_hdr);
 
-		data += sizeof(*tlv_hdr) + tlv_len;
-		pos += sizeof(*tlv_hdr) + tlv_len;
+		send_attr->data = data;
+		pos += send_attr->tlv_len;
+		data += send_attr->tlv_len;
 	}
 
 	sctx->cmd = cmd;
@@ -180,7 +196,7 @@ out:
 static int tlv_get(struct btrfs_send_stream *sctx, int attr, void **data, int *len)
 {
 	int ret;
-	struct btrfs_tlv_header *hdr;
+	struct btrfs_send_attribute *send_attr;
 
 	if (attr <= 0 || attr > BTRFS_SEND_A_MAX) {
 		error("invalid attribute requested, attr = %d", attr);
@@ -188,15 +204,15 @@ static int tlv_get(struct btrfs_send_stream *sctx, int attr, void **data, int *l
 		goto out;
 	}
 
-	hdr = sctx->cmd_attrs[attr];
-	if (!hdr) {
+	send_attr = &sctx->cmd_attrs[attr];
+	if (!send_attr->data) {
 		error("attribute %d requested but not present", attr);
 		ret = -ENOENT;
 		goto out;
 	}
 
-	*len = le16_to_cpu(hdr->tlv_len);
-	*data = hdr + 1;
+	*len = send_attr->tlv_len;
+	*data = send_attr->data;
 
 	ret = 0;
 
-- 
2.32.0

[PATCH v10 02/10] btrfs-progs: receive: dynamically allocate sctx->read_buf

[Omar Sandoval]

From: Boris Burkov <boris@bur.io>

In send stream v2, write commands can now be an arbitrary size. For that
reason, we can no longer allocate a fixed array in sctx for read_cmd.
Instead, read_cmd dynamically allocates sctx->read_buf. To avoid
needless reallocations, we reuse read_buf between read_cmd calls by also
keeping track of the size of the allocated buffer in sctx->read_buf_sz.

We do the first allocation of the old default size at the start of
processing the stream, and we only reallocate if we encounter a command
that needs a larger buffer.

Signed-off-by: Boris Burkov <boris@bur.io>
---
 common/send-stream.c | 55 ++++++++++++++++++++++++++++----------------
 send.h               |  2 +-
 2 files changed, 36 insertions(+), 21 deletions(-)

diff --git a/common/send-stream.c b/common/send-stream.c
index cd5aa311..3d3585c3 100644
--- a/common/send-stream.c
+++ b/common/send-stream.c
@@ -35,11 +35,11 @@ struct btrfs_send_attribute {
 };
 
 struct btrfs_send_stream {
-	char read_buf[BTRFS_SEND_BUF_SIZE];
+	char *read_buf;
+	size_t read_buf_sz;
 	int fd;
 
 	int cmd;
-	struct btrfs_cmd_header *cmd_hdr;
 	struct btrfs_send_attribute cmd_attrs[BTRFS_SEND_A_MAX + 1];
 	u32 version;
 
@@ -111,11 +111,12 @@ static int read_cmd(struct btrfs_send_stream *sctx)
 	u32 pos;
 	u32 crc;
 	u32 crc2;
+	struct btrfs_cmd_header *cmd_hdr;
+	size_t buf_len;
 
 	memset(sctx->cmd_attrs, 0, sizeof(sctx->cmd_attrs));
 
-	ASSERT(sizeof(*sctx->cmd_hdr) <= sizeof(sctx->read_buf));
-	ret = read_buf(sctx, sctx->read_buf, sizeof(*sctx->cmd_hdr));
+	ret = read_buf(sctx, sctx->read_buf, sizeof(*cmd_hdr));
 	if (ret < 0)
 		goto out;
 	if (ret) {
@@ -124,18 +125,22 @@ static int read_cmd(struct btrfs_send_stream *sctx)
 		goto out;
 	}
 
-	sctx->cmd_hdr = (struct btrfs_cmd_header *)sctx->read_buf;
-	cmd = le16_to_cpu(sctx->cmd_hdr->cmd);
-	cmd_len = le32_to_cpu(sctx->cmd_hdr->len);
-
-	if (cmd_len + sizeof(*sctx->cmd_hdr) >= sizeof(sctx->read_buf)) {
-		ret = -EINVAL;
-		error("command length %u too big for buffer %zu",
-				cmd_len, sizeof(sctx->read_buf));
-		goto out;
+	cmd_hdr = (struct btrfs_cmd_header *)sctx->read_buf;
+	cmd_len = le32_to_cpu(cmd_hdr->len);
+	cmd = le16_to_cpu(cmd_hdr->cmd);
+	buf_len = sizeof(*cmd_hdr) + cmd_len;
+	if (sctx->read_buf_sz < buf_len) {
+		sctx->read_buf = realloc(sctx->read_buf, buf_len);
+		if (!sctx->read_buf) {
+			ret = -ENOMEM;
+			error("failed to reallocate read buffer for cmd");
+			goto out;
+		}
+		sctx->read_buf_sz = buf_len;
+		/* We need to reset cmd_hdr after realloc of sctx->read_buf */
+		cmd_hdr = (struct btrfs_cmd_header *)sctx->read_buf;
 	}
-
-	data = sctx->read_buf + sizeof(*sctx->cmd_hdr);
+	data = sctx->read_buf + sizeof(*cmd_hdr);
 	ret = read_buf(sctx, data, cmd_len);
 	if (ret < 0)
 		goto out;
@@ -145,11 +150,12 @@ static int read_cmd(struct btrfs_send_stream *sctx)
 		goto out;
 	}
 
-	crc = le32_to_cpu(sctx->cmd_hdr->crc);
-	sctx->cmd_hdr->crc = 0;
+	crc = le32_to_cpu(cmd_hdr->crc);
+	/* in send, crc is computed with header crc = 0, replicate that */
+	cmd_hdr->crc = 0;
 
 	crc2 = crc32c(0, (unsigned char*)sctx->read_buf,
-			sizeof(*sctx->cmd_hdr) + cmd_len);
+			sizeof(*cmd_hdr) + cmd_len);
 
 	if (crc != crc2) {
 		ret = -EINVAL;
@@ -524,19 +530,28 @@ int btrfs_read_and_process_send_stream(int fd,
 		goto out;
 	}
 
+	sctx.read_buf = malloc(BTRFS_SEND_BUF_SIZE_V1);
+	if (!sctx.read_buf) {
+		ret = -ENOMEM;
+		error("unable to allocate send stream read buffer");
+		goto out;
+	}
+	sctx.read_buf_sz = BTRFS_SEND_BUF_SIZE_V1;
+
 	while (1) {
 		ret = read_and_process_cmd(&sctx);
 		if (ret < 0) {
 			last_err = ret;
 			errors++;
 			if (max_errors > 0 && errors >= max_errors)
-				goto out;
+				break;
 		} else if (ret > 0) {
 			if (!honor_end_cmd)
 				ret = 0;
-			goto out;
+			break;
 		}
 	}
+	free(sctx.read_buf);
 
 out:
 	if (last_err && !ret)
diff --git a/send.h b/send.h
index 8dd865ec..228928a0 100644
--- a/send.h
+++ b/send.h
@@ -33,7 +33,7 @@ extern "C" {
 #define BTRFS_SEND_STREAM_MAGIC "btrfs-stream"
 #define BTRFS_SEND_STREAM_VERSION 1
 
-#define BTRFS_SEND_BUF_SIZE SZ_64K
+#define BTRFS_SEND_BUF_SIZE_V1 SZ_64K
 #define BTRFS_SEND_READ_SIZE (1024 * 48)
 
 enum btrfs_tlv_type {
-- 
2.32.0

[PATCH v10 03/10] btrfs-progs: receive: support v2 send stream DATA tlv format

[Omar Sandoval]

From: Boris Burkov <borisb@fb.com>

The new format privileges the BTRFS_SEND_A_DATA attribute by
guaranteeing it will always be the last attribute in any command that
needs it, and by implicitly encoding the data length as the difference
between the total command length in the command header and the sizes of
the rest of the attributes (and of course the tlv_type identifying the
DATA attribute). To parse the new stream, we must read the tlv_type and
if it is not DATA, we proceed normally, but if it is DATA, we don't
parse a tlv_len but simply compute the length.

In addition, we add some bounds checking when parsing each chunk of
data, as well as for the tlv_len itself.

Signed-off-by: Boris Burkov <boris@bur.io>
---
 common/send-stream.c | 36 ++++++++++++++++++++++++++----------
 1 file changed, 26 insertions(+), 10 deletions(-)

diff --git a/common/send-stream.c b/common/send-stream.c
index 3d3585c3..4d819185 100644
--- a/common/send-stream.c
+++ b/common/send-stream.c
@@ -165,28 +165,44 @@ static int read_cmd(struct btrfs_send_stream *sctx)
 
 	pos = 0;
 	while (pos < cmd_len) {
-		struct btrfs_tlv_header *tlv_hdr;
 		u16 tlv_type;
-		u16 tlv_len;
 		struct btrfs_send_attribute *send_attr;
 
-		tlv_hdr = (struct btrfs_tlv_header *)data;
-		tlv_type = le16_to_cpu(tlv_hdr->tlv_type);
-		tlv_len = le16_to_cpu(tlv_hdr->tlv_len);
+		if (cmd_len - pos < sizeof(__le16)) {
+			error("send stream is truncated");
+			ret = -EINVAL;
+			goto out;
+		}
+		tlv_type = le16_to_cpu(*(__le16 *)data);
 
 		if (tlv_type == 0 || tlv_type > BTRFS_SEND_A_MAX) {
-			error("invalid tlv in cmd tlv_type = %hu, tlv_len = %hu",
-					tlv_type, tlv_len);
+			error("invalid tlv in cmd tlv_type = %hu", tlv_type);
 			ret = -EINVAL;
 			goto out;
 		}
 
 		send_attr = &sctx->cmd_attrs[tlv_type];
 		send_attr->tlv_type = tlv_type;
-		send_attr->tlv_len = tlv_len;
-		pos += sizeof(*tlv_hdr);
-		data += sizeof(*tlv_hdr);
 
+		pos += sizeof(tlv_type);
+		data += sizeof(tlv_type);
+		if (sctx->version == 2 && tlv_type == BTRFS_SEND_A_DATA) {
+			send_attr->tlv_len = cmd_len - pos;
+		} else {
+			if (cmd_len - pos < sizeof(__le16)) {
+				error("send stream is truncated");
+				ret = -EINVAL;
+				goto out;
+			}
+			send_attr->tlv_len = le16_to_cpu(*(__le16 *)data);
+			pos += sizeof(__le16);
+			data += sizeof(__le16);
+		}
+		if (cmd_len - pos < send_attr->tlv_len) {
+			error("send stream is truncated");
+			ret = -EINVAL;
+			goto out;
+		}
 		send_attr->data = data;
 		pos += send_attr->tlv_len;
 		data += send_attr->tlv_len;
-- 
2.32.0

[PATCH v10 04/10] btrfs-progs: receive: add send stream v2 cmds and attrs to send.h

[Omar Sandoval]

From: Boris Burkov <boris@bur.io>

Send stream v2 adds three commands and several attributes associated to
those commands. Before we implement processing them, add all the
commands and attributes. This avoids leaving the enums in an
intermediate state that doesn't correspond to any version of send
stream.

Signed-off-by: Boris Burkov <boris@bur.io>
---
 send.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/send.h b/send.h
index 228928a0..3c47e0c7 100644
--- a/send.h
+++ b/send.h
@@ -98,6 +98,11 @@ enum btrfs_send_cmd {
 
 	BTRFS_SEND_C_END,
 	BTRFS_SEND_C_UPDATE_EXTENT,
+
+	BTRFS_SEND_C_FALLOCATE,
+	BTRFS_SEND_C_SETFLAGS,
+	BTRFS_SEND_C_ENCODED_WRITE,
+
 	__BTRFS_SEND_C_MAX,
 };
 #define BTRFS_SEND_C_MAX (__BTRFS_SEND_C_MAX - 1)
@@ -136,6 +141,16 @@ enum {
 	BTRFS_SEND_A_CLONE_OFFSET,
 	BTRFS_SEND_A_CLONE_LEN,
 
+	BTRFS_SEND_A_FALLOCATE_MODE,
+
+	BTRFS_SEND_A_SETFLAGS_FLAGS,
+
+	BTRFS_SEND_A_UNENCODED_FILE_LEN,
+	BTRFS_SEND_A_UNENCODED_LEN,
+	BTRFS_SEND_A_UNENCODED_OFFSET,
+	BTRFS_SEND_A_COMPRESSION,
+	BTRFS_SEND_A_ENCRYPTION,
+
 	__BTRFS_SEND_A_MAX,
 };
 #define BTRFS_SEND_A_MAX (__BTRFS_SEND_A_MAX - 1)
-- 
2.32.0

[PATCH v10 05/10] btrfs-progs: receive: process encoded_write commands

[Omar Sandoval]

From: Boris Burkov <borisb@fb.com>

Add a new btrfs_send_op and support for both dumping and proper receive
processing which does actual encoded writes.

Encoded writes are only allowed on a file descriptor opened with an
extra flag that allows encoded writes, so we also add support for this
flag when opening or reusing a file for writing.

Signed-off-by: Boris Burkov <boris@bur.io>
---
 cmds/receive-dump.c  |  16 +++++-
 cmds/receive.c       |  47 +++++++++++++++
 common/send-stream.c |  22 ++++++++
 common/send-stream.h |   4 ++
 ioctl.h              | 132 +++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 220 insertions(+), 1 deletion(-)

diff --git a/cmds/receive-dump.c b/cmds/receive-dump.c
index 648d9314..20ec2b70 100644
--- a/cmds/receive-dump.c
+++ b/cmds/receive-dump.c
@@ -316,6 +316,19 @@ static int print_update_extent(const char *path, u64 offset, u64 len,
 			  offset, len);
 }
 
+static int print_encoded_write(const char *path, const void *data, u64 offset,
+			       u64 len, u64 unencoded_file_len,
+			       u64 unencoded_len, u64 unencoded_offset,
+			       u32 compression, u32 encryption, void *user)
+{
+	return PRINT_DUMP(user, path, "encoded_write",
+			  "offset=%llu len=%llu, unencoded_file_len=%llu, "
+			  "unencoded_len=%llu, unencoded_offset=%llu, "
+			  "compression=%u, encryption=%u",
+			  offset, len, unencoded_file_len, unencoded_len,
+			  unencoded_offset, compression, encryption);
+}
+
 struct btrfs_send_ops btrfs_print_send_ops = {
 	.subvol = print_subvol,
 	.snapshot = print_snapshot,
@@ -337,5 +350,6 @@ struct btrfs_send_ops btrfs_print_send_ops = {
 	.chmod = print_chmod,
 	.chown = print_chown,
 	.utimes = print_utimes,
-	.update_extent = print_update_extent
+	.update_extent = print_update_extent,
+	.encoded_write = print_encoded_write,
 };
diff --git a/cmds/receive.c b/cmds/receive.c
index 4dd01fd3..b43c298f 100644
--- a/cmds/receive.c
+++ b/cmds/receive.c
@@ -29,12 +29,14 @@
 #include <assert.h>
 #include <getopt.h>
 #include <limits.h>
+#include <errno.h>
 
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/ioctl.h>
 #include <sys/time.h>
 #include <sys/types.h>
+#include <sys/uio.h>
 #include <sys/xattr.h>
 #include <uuid/uuid.h>
 
@@ -51,6 +53,7 @@
 #include "cmds/receive-dump.h"
 #include "common/help.h"
 #include "common/path-utils.h"
+#include "stubs.h"
 
 struct btrfs_receive
 {
@@ -986,6 +989,49 @@ static int process_update_extent(const char *path, u64 offset, u64 len,
 	return 0;
 }
 
+static int process_encoded_write(const char *path, const void *data, u64 offset,
+	u64 len, u64 unencoded_file_len, u64 unencoded_len,
+	u64 unencoded_offset, u32 compression, u32 encryption, void *user)
+{
+	int ret;
+	struct btrfs_receive *rctx = user;
+	char full_path[PATH_MAX];
+	struct iovec iov = { (char *)data, len };
+	struct btrfs_ioctl_encoded_io_args encoded = {
+		.iov = &iov,
+		.iovcnt = 1,
+		.offset = offset,
+		.len = unencoded_file_len,
+		.unencoded_len = unencoded_len,
+		.unencoded_offset = unencoded_offset,
+		.compression = compression,
+		.encryption = encryption,
+	};
+
+	if (encryption) {
+		error("encoded_write: encryption not supported");
+		return -EOPNOTSUPP;
+	}
+
+	ret = path_cat_out(full_path, rctx->full_subvol_path, path);
+	if (ret < 0) {
+		error("encoded_write: path invalid: %s", path);
+		return ret;
+	}
+
+	ret = open_inode_for_write(rctx, full_path);
+	if (ret < 0)
+		return ret;
+
+	ret = ioctl(rctx->write_fd, BTRFS_IOC_ENCODED_WRITE, &encoded);
+	if (ret < 0) {
+		ret = -errno;
+		error("encoded_write: writing to %s failed: %m", path);
+		return ret;
+	}
+	return 0;
+}
+
 static struct btrfs_send_ops send_ops = {
 	.subvol = process_subvol,
 	.snapshot = process_snapshot,
@@ -1008,6 +1054,7 @@ static struct btrfs_send_ops send_ops = {
 	.chown = process_chown,
 	.utimes = process_utimes,
 	.update_extent = process_update_extent,
+	.encoded_write = process_encoded_write,
 };
 
 static int do_receive(struct btrfs_receive *rctx, const char *tomnt,
diff --git a/common/send-stream.c b/common/send-stream.c
index 4d819185..044e101b 100644
--- a/common/send-stream.c
+++ b/common/send-stream.c
@@ -354,6 +354,8 @@ static int read_and_process_cmd(struct btrfs_send_stream *sctx)
 	struct timespec mt;
 	u8 uuid[BTRFS_UUID_SIZE];
 	u8 clone_uuid[BTRFS_UUID_SIZE];
+	u32 compression;
+	u32 encryption;
 	u64 tmp;
 	u64 tmp2;
 	u64 ctransid;
@@ -362,6 +364,9 @@ static int read_and_process_cmd(struct btrfs_send_stream *sctx)
 	u64 dev;
 	u64 clone_offset;
 	u64 offset;
+	u64 unencoded_file_len;
+	u64 unencoded_len;
+	u64 unencoded_offset;
 	int len;
 	int xattr_len;
 
@@ -436,6 +441,23 @@ static int read_and_process_cmd(struct btrfs_send_stream *sctx)
 		TLV_GET(sctx, BTRFS_SEND_A_DATA, &data, &len);
 		ret = sctx->ops->write(path, data, offset, len, sctx->user);
 		break;
+	case BTRFS_SEND_C_ENCODED_WRITE:
+		TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
+		TLV_GET_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, &offset);
+		TLV_GET_U64(sctx, BTRFS_SEND_A_UNENCODED_FILE_LEN,
+			    &unencoded_file_len);
+		TLV_GET_U64(sctx, BTRFS_SEND_A_UNENCODED_LEN, &unencoded_len);
+		TLV_GET_U64(sctx, BTRFS_SEND_A_UNENCODED_OFFSET,
+			    &unencoded_offset);
+		TLV_GET_U32(sctx, BTRFS_SEND_A_COMPRESSION, &compression);
+		TLV_GET_U32(sctx, BTRFS_SEND_A_ENCRYPTION, &encryption);
+		TLV_GET(sctx, BTRFS_SEND_A_DATA, &data, &len);
+		ret = sctx->ops->encoded_write(path, data, offset, len,
+					       unencoded_file_len,
+					       unencoded_len, unencoded_offset,
+					       compression, encryption,
+					       sctx->user);
+		break;
 	case BTRFS_SEND_C_CLONE:
 		TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
 		TLV_GET_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, &offset);
diff --git a/common/send-stream.h b/common/send-stream.h
index 39901f86..607bc007 100644
--- a/common/send-stream.h
+++ b/common/send-stream.h
@@ -66,6 +66,10 @@ struct btrfs_send_ops {
 		      struct timespec *mt, struct timespec *ct,
 		      void *user);
 	int (*update_extent)(const char *path, u64 offset, u64 len, void *user);
+	int (*encoded_write)(const char *path, const void *data, u64 offset,
+			     u64 len, u64 unencoded_file_len, u64 unencoded_len,
+			     u64 unencoded_offset, u32 compression,
+			     u32 encryption, void *user);
 };
 
 int btrfs_read_and_process_send_stream(int fd,
diff --git a/ioctl.h b/ioctl.h
index 9e1e3403..a472dbd2 100644
--- a/ioctl.h
+++ b/ioctl.h
@@ -775,6 +775,134 @@ struct btrfs_ioctl_get_subvol_rootref_args {
 };
 BUILD_ASSERT(sizeof(struct btrfs_ioctl_get_subvol_rootref_args) == 4096);
 
+/*
+ * Data and metadata for an encoded read or write.
+ *
+ * Encoded I/O bypasses any encoding automatically done by the filesystem (e.g.,
+ * compression). This can be used to read the compressed contents of a file or
+ * write pre-compressed data directly to a file.
+ *
+ * BTRFS_IOC_ENCODED_READ and BTRFS_IOC_ENCODED_WRITE are essentially
+ * preadv/pwritev with additional metadata about how the data is encoded and the
+ * size of the unencoded data.
+ *
+ * BTRFS_IOC_ENCODED_READ fills the given iovecs with the encoded data, fills
+ * the metadata fields, and returns the size of the encoded data. It reads one
+ * extent per call. It can also read data which is not encoded.
+ *
+ * BTRFS_IOC_ENCODED_WRITE uses the metadata fields, writes the encoded data
+ * from the iovecs, and returns the size of the encoded data. Note that the
+ * encoded data is not validated when it is written; if it is not valid (e.g.,
+ * it cannot be decompressed), then a subsequent read may return an error.
+ *
+ * Since the filesystem page cache contains decoded data, encoded I/O bypasses
+ * the page cache. Encoded I/O requires CAP_SYS_ADMIN.
+ */
+struct btrfs_ioctl_encoded_io_args {
+	/* Input parameters for both reads and writes. */
+
+	/*
+	 * iovecs containing encoded data.
+	 *
+	 * For reads, if the size of the encoded data is larger than the sum of
+	 * iov[n].iov_len for 0 <= n < iovcnt, then the ioctl fails with
+	 * ENOBUFS.
+	 *
+	 * For writes, the size of the encoded data is the sum of iov[n].iov_len
+	 * for 0 <= n < iovcnt. This must be less than 128 KiB (this limit may
+	 * increase in the future). This must also be less than or equal to
+	 * unencoded_len.
+	 */
+	const struct iovec *iov;
+	/* Number of iovecs. */
+	unsigned long iovcnt;
+	/*
+	 * Offset in file.
+	 *
+	 * For writes, must be aligned to the sector size of the filesystem.
+	 */
+	__s64 offset;
+	/* Currently must be zero. */
+	__u64 flags;
+
+	/*
+	 * For reads, the following members are filled in with the metadata for
+	 * the encoded data.
+	 * For writes, the following members must be set to the metadata for the
+	 * encoded data.
+	 */
+
+	/*
+	 * Length of the data in the file.
+	 *
+	 * Must be less than or equal to unencoded_len - unencoded_offset. For
+	 * writes, must be aligned to the sector size of the filesystem unless
+	 * the data ends at or beyond the current end of the file.
+	 */
+	__u64 len;
+	/*
+	 * Length of the unencoded (i.e., decrypted and decompressed) data.
+	 *
+	 * For writes, must be no more than 128 KiB (this limit may increase in
+	 * the future). If the unencoded data is actually longer than
+	 * unencoded_len, then it is truncated; if it is shorter, then it is
+	 * extended with zeroes.
+	 */
+	__u64 unencoded_len;
+	/*
+	 * Offset from the first byte of the unencoded data to the first byte of
+	 * logical data in the file.
+	 *
+	 * Must be less than unencoded_len.
+	 */
+	__u64 unencoded_offset;
+	/*
+	 * BTRFS_ENCODED_IO_COMPRESSION_* type.
+	 *
+	 * For writes, must not be BTRFS_ENCODED_IO_COMPRESSION_NONE.
+	 */
+	__u32 compression;
+	/* Currently always BTRFS_ENCODED_IO_ENCRYPTION_NONE. */
+	__u32 encryption;
+	/*
+	 * Reserved for future expansion.
+	 *
+	 * For reads, always returned as zero. Users should check for non-zero
+	 * bytes. If there are any, then the kernel has a newer version of this
+	 * structure with additional information that the user definition is
+	 * missing.
+	 *
+	 * For writes, must be zeroed.
+	 */
+	__u8 reserved[32];
+};
+
+/* Data is not compressed. */
+#define BTRFS_ENCODED_IO_COMPRESSION_NONE 0
+/* Data is compressed as a single zlib stream. */
+#define BTRFS_ENCODED_IO_COMPRESSION_ZLIB 1
+/*
+ * Data is compressed as a single zstd frame with the windowLog compression
+ * parameter set to no more than 17.
+ */
+#define BTRFS_ENCODED_IO_COMPRESSION_ZSTD 2
+/*
+ * Data is compressed page by page (using the page size indicated by the name of
+ * the constant) with LZO1X and wrapped in the format documented in
+ * fs/btrfs/lzo.c. For writes, the compression page size must match the
+ * filesystem page size.
+ */
+#define BTRFS_ENCODED_IO_COMPRESSION_LZO_4K 3
+#define BTRFS_ENCODED_IO_COMPRESSION_LZO_8K 4
+#define BTRFS_ENCODED_IO_COMPRESSION_LZO_16K 5
+#define BTRFS_ENCODED_IO_COMPRESSION_LZO_32K 6
+#define BTRFS_ENCODED_IO_COMPRESSION_LZO_64K 7
+#define BTRFS_ENCODED_IO_COMPRESSION_TYPES 8
+
+/* Data is not encrypted. */
+#define BTRFS_ENCODED_IO_ENCRYPTION_NONE 0
+#define BTRFS_ENCODED_IO_ENCRYPTION_TYPES 1
+
 /* Error codes as returned by the kernel */
 enum btrfs_err_code {
 	notused,
@@ -949,6 +1077,10 @@ static inline char *btrfs_err_str(enum btrfs_err_code err_code)
 				struct btrfs_ioctl_ino_lookup_user_args)
 #define BTRFS_IOC_SNAP_DESTROY_V2 _IOW(BTRFS_IOCTL_MAGIC, 63, \
 				   struct btrfs_ioctl_vol_args_v2)
+#define BTRFS_IOC_ENCODED_READ _IOR(BTRFS_IOCTL_MAGIC, 64, \
+				    struct btrfs_ioctl_encoded_io_args)
+#define BTRFS_IOC_ENCODED_WRITE _IOW(BTRFS_IOCTL_MAGIC, 64, \
+				     struct btrfs_ioctl_encoded_io_args)
 
 #ifdef __cplusplus
 }
-- 
2.32.0

[PATCH v10 06/10] btrfs-progs: receive: encoded_write fallback to explicit decode and write

[Omar Sandoval]

From: Boris Burkov <boris@bur.io>

An encoded_write can fail if the file system it is being applied to does
not support encoded writes or if it can't find enough contiguous space
to accommodate the encoded extent. In those cases, we can likely still
process an encoded_write by explicitly decoding the data and doing a
normal write.

Add the necessary fallback path for decoding data compressed with zlib,
lzo, or zstd. zlib and zstd have reusable decoding context data
structures which we cache in the receive context so that we don't have
to recreate them on every encoded_write.

Finally, add a command line flag for force-decompress which causes
receive to always use the fallback path rather than first attempting the
encoded write.

Signed-off-by: Boris Burkov <boris@bur.io>
---
 Documentation/btrfs-receive.asciidoc |   4 +
 cmds/receive.c                       | 266 ++++++++++++++++++++++++++-
 2 files changed, 261 insertions(+), 9 deletions(-)

diff --git a/Documentation/btrfs-receive.asciidoc b/Documentation/btrfs-receive.asciidoc
index e4c4d2c0..354a71dc 100644
--- a/Documentation/btrfs-receive.asciidoc
+++ b/Documentation/btrfs-receive.asciidoc
@@ -60,6 +60,10 @@ By default the mountpoint is searched in '/proc/self/mounts'.
 If '/proc' is not accessible, eg. in a chroot environment, use this option to
 tell us where this filesystem is mounted.
 
+--force-decompress::
+if the stream contains compressed data (see '--compressed-data' in
+`btrfs-send`(8)), always decompress it instead of writing it with encoded I/O.
+
 --dump::
 dump the stream metadata, one line per operation
 +
diff --git a/cmds/receive.c b/cmds/receive.c
index b43c298f..7506f992 100644
--- a/cmds/receive.c
+++ b/cmds/receive.c
@@ -40,6 +40,10 @@
 #include <sys/xattr.h>
 #include <uuid/uuid.h>
 
+#include <lzo/lzo1x.h>
+#include <zlib.h>
+#include <zstd.h>
+
 #include "kernel-shared/ctree.h"
 #include "ioctl.h"
 #include "cmds/commands.h"
@@ -79,6 +83,12 @@ struct btrfs_receive
 	struct subvol_uuid_search sus;
 
 	int honor_end_cmd;
+
+	int force_decompress;
+
+	/* Reuse stream objects for encoded_write decompression fallback */
+	ZSTD_DStream *zstd_dstream;
+	z_stream *zlib_stream;
 };
 
 static int finish_subvol(struct btrfs_receive *rctx)
@@ -989,9 +999,222 @@ static int process_update_extent(const char *path, u64 offset, u64 len,
 	return 0;
 }
 
+static int decompress_zlib(struct btrfs_receive *rctx, const char *encoded_data,
+			   u64 encoded_len, char *unencoded_data,
+			   u64 unencoded_len)
+{
+	bool init = false;
+	int ret;
+
+	if (!rctx->zlib_stream) {
+		init = true;
+		rctx->zlib_stream = malloc(sizeof(z_stream));
+		if (!rctx->zlib_stream) {
+			error("failed to allocate zlib stream %m");
+			return -ENOMEM;
+		}
+	}
+	rctx->zlib_stream->next_in = (void *)encoded_data;
+	rctx->zlib_stream->avail_in = encoded_len;
+	rctx->zlib_stream->next_out = (void *)unencoded_data;
+	rctx->zlib_stream->avail_out = unencoded_len;
+
+	if (init) {
+		rctx->zlib_stream->zalloc = Z_NULL;
+		rctx->zlib_stream->zfree = Z_NULL;
+		rctx->zlib_stream->opaque = Z_NULL;
+		ret = inflateInit(rctx->zlib_stream);
+	} else {
+		ret = inflateReset(rctx->zlib_stream);
+	}
+	if (ret != Z_OK) {
+		error("zlib inflate init failed: %d", ret);
+		return -EIO;
+	}
+
+	while (rctx->zlib_stream->avail_in > 0 &&
+	       rctx->zlib_stream->avail_out > 0) {
+		ret = inflate(rctx->zlib_stream, Z_FINISH);
+		if (ret == Z_STREAM_END) {
+			break;
+		} else if (ret != Z_OK) {
+			error("zlib inflate failed: %d", ret);
+			return -EIO;
+		}
+	}
+	return 0;
+}
+
+static int decompress_zstd(struct btrfs_receive *rctx, const char *encoded_buf,
+			   u64 encoded_len, char *unencoded_buf,
+			   u64 unencoded_len)
+{
+	ZSTD_inBuffer in_buf = {
+		.src = encoded_buf,
+		.size = encoded_len
+	};
+	ZSTD_outBuffer out_buf = {
+		.dst = unencoded_buf,
+		.size = unencoded_len
+	};
+	size_t ret;
+
+	if (!rctx->zstd_dstream) {
+		rctx->zstd_dstream = ZSTD_createDStream();
+		if (!rctx->zstd_dstream) {
+			error("failed to create zstd dstream");
+			return -ENOMEM;
+		}
+	}
+	ret = ZSTD_initDStream(rctx->zstd_dstream);
+	if (ZSTD_isError(ret)) {
+		error("failed to init zstd stream: %s", ZSTD_getErrorName(ret));
+		return -EIO;
+	}
+	while (in_buf.pos < in_buf.size && out_buf.pos < out_buf.size) {
+		ret = ZSTD_decompressStream(rctx->zstd_dstream, &out_buf, &in_buf);
+		if (ret == 0) {
+			break;
+		} else if (ZSTD_isError(ret)) {
+			error("failed to decompress zstd stream: %s",
+			      ZSTD_getErrorName(ret));
+			return -EIO;
+		}
+	}
+	return 0;
+}
+
+static int decompress_lzo(const char *encoded_data, u64 encoded_len,
+			  char *unencoded_data, u64 unencoded_len,
+			  unsigned int page_size)
+{
+	uint32_t total_len;
+	size_t in_pos, out_pos;
+
+	if (encoded_len < 4) {
+		error("lzo header is truncated");
+		return -EIO;
+	}
+	memcpy(&total_len, encoded_data, 4);
+	total_len = le32toh(total_len);
+	if (total_len > encoded_len) {
+		error("lzo header is invalid");
+		return -EIO;
+	}
+
+	in_pos = 4;
+	out_pos = 0;
+	while (in_pos < total_len && out_pos < unencoded_len) {
+		size_t page_remaining;
+		uint32_t src_len;
+		lzo_uint dst_len;
+		int ret;
+
+		page_remaining = -in_pos % page_size;
+		if (page_remaining < 4) {
+			if (total_len - in_pos <= page_remaining)
+				break;
+			in_pos += page_remaining;
+		}
+
+		if (total_len - in_pos < 4) {
+			error("lzo segment header is truncated");
+			return -EIO;
+		}
+
+		memcpy(&src_len, encoded_data + in_pos, 4);
+		src_len = le32toh(src_len);
+		in_pos += 4;
+		if (src_len > total_len - in_pos) {
+			error("lzo segment header is invalid");
+			return -EIO;
+		}
+
+		dst_len = page_size;
+		ret = lzo1x_decompress_safe((void *)(encoded_data + in_pos),
+					    src_len,
+					    (void *)(unencoded_data + out_pos),
+					    &dst_len, NULL);
+		if (ret != LZO_E_OK) {
+			error("lzo1x_decompress_safe failed: %d", ret);
+			return -EIO;
+		}
+
+		in_pos += src_len;
+		out_pos += dst_len;
+	}
+	return 0;
+}
+
+static int decompress_and_write(struct btrfs_receive *rctx,
+				const char *encoded_data, u64 offset,
+				u64 encoded_len, u64 unencoded_file_len,
+				u64 unencoded_len, u64 unencoded_offset,
+				u32 compression)
+{
+	int ret = 0;
+	size_t pos;
+	ssize_t w;
+	char *unencoded_data;
+	int page_shift;
+
+	unencoded_data = calloc(unencoded_len, 1);
+	if (!unencoded_data) {
+		error("allocating space for unencoded data failed: %m");
+		return -errno;
+	}
+
+	switch (compression) {
+	case BTRFS_ENCODED_IO_COMPRESSION_ZLIB:
+		ret = decompress_zlib(rctx, encoded_data, encoded_len,
+				      unencoded_data, unencoded_len);
+		if (ret)
+			goto out;
+		break;
+	case BTRFS_ENCODED_IO_COMPRESSION_ZSTD:
+		ret = decompress_zstd(rctx, encoded_data, encoded_len,
+				      unencoded_data, unencoded_len);
+		if (ret)
+			goto out;
+		break;
+	case BTRFS_ENCODED_IO_COMPRESSION_LZO_4K:
+	case BTRFS_ENCODED_IO_COMPRESSION_LZO_8K:
+	case BTRFS_ENCODED_IO_COMPRESSION_LZO_16K:
+	case BTRFS_ENCODED_IO_COMPRESSION_LZO_32K:
+	case BTRFS_ENCODED_IO_COMPRESSION_LZO_64K:
+		page_shift = compression - BTRFS_ENCODED_IO_COMPRESSION_LZO_4K + 12;
+		ret = decompress_lzo(encoded_data, encoded_len, unencoded_data,
+				     unencoded_len, 1U << page_shift);
+		if (ret)
+			goto out;
+		break;
+	default:
+		error("unknown compression: %d", compression);
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
+	pos = unencoded_offset;
+	while (pos < unencoded_file_len) {
+		w = pwrite(rctx->write_fd, unencoded_data + pos,
+			   unencoded_file_len - pos, offset);
+		if (w < 0) {
+			ret = -errno;
+			error("writing unencoded data failed: %m");
+			goto out;
+		}
+		pos += w;
+		offset += w;
+	}
+out:
+	free(unencoded_data);
+	return ret;
+}
+
 static int process_encoded_write(const char *path, const void *data, u64 offset,
-	u64 len, u64 unencoded_file_len, u64 unencoded_len,
-	u64 unencoded_offset, u32 compression, u32 encryption, void *user)
+				 u64 len, u64 unencoded_file_len,
+				 u64 unencoded_len, u64 unencoded_offset,
+				 u32 compression, u32 encryption, void *user)
 {
 	int ret;
 	struct btrfs_receive *rctx = user;
@@ -1007,6 +1230,7 @@ static int process_encoded_write(const char *path, const void *data, u64 offset,
 		.compression = compression,
 		.encryption = encryption,
 	};
+	bool encoded_write = !rctx->force_decompress;
 
 	if (encryption) {
 		error("encoded_write: encryption not supported");
@@ -1023,13 +1247,21 @@ static int process_encoded_write(const char *path, const void *data, u64 offset,
 	if (ret < 0)
 		return ret;
 
-	ret = ioctl(rctx->write_fd, BTRFS_IOC_ENCODED_WRITE, &encoded);
-	if (ret < 0) {
-		ret = -errno;
-		error("encoded_write: writing to %s failed: %m", path);
-		return ret;
+	if (encoded_write) {
+		ret = ioctl(rctx->write_fd, BTRFS_IOC_ENCODED_WRITE, &encoded);
+		if (ret >= 0)
+			return 0;
+		/* Fall back for these errors, fail hard for anything else. */
+		if (errno != ENOSPC && errno != EOPNOTSUPP && errno != EINVAL) {
+			ret = -errno;
+			error("encoded_write: writing to %s failed: %m", path);
+			return ret;
+		}
 	}
-	return 0;
+
+	return decompress_and_write(rctx, data, offset, len, unencoded_file_len,
+				    unencoded_len, unencoded_offset,
+				    compression);
 }
 
 static struct btrfs_send_ops send_ops = {
@@ -1209,6 +1441,12 @@ out:
 		close(rctx->dest_dir_fd);
 		rctx->dest_dir_fd = -1;
 	}
+	if (rctx->zstd_dstream)
+		ZSTD_freeDStream(rctx->zstd_dstream);
+	if (rctx->zlib_stream) {
+		inflateEnd(rctx->zlib_stream);
+		free(rctx->zlib_stream);
+	}
 
 	return ret;
 }
@@ -1239,6 +1477,9 @@ static const char * const cmd_receive_usage[] = {
 	"-m ROOTMOUNT     the root mount point of the destination filesystem.",
 	"                 If /proc is not accessible, use this to tell us where",
 	"                 this file system is mounted.",
+	"--force-decompress",
+	"                 if the stream contains compressed data, always",
+	"                 decompress it instead of writing it with encoded I/O",
 	"--dump           dump stream metadata, one line per operation,",
 	"                 does not require the MOUNT parameter",
 	"-v               deprecated, alias for global -v option",
@@ -1282,12 +1523,16 @@ static int cmd_receive(const struct cmd_struct *cmd, int argc, char **argv)
 	optind = 0;
 	while (1) {
 		int c;
-		enum { GETOPT_VAL_DUMP = 257 };
+		enum {
+			GETOPT_VAL_DUMP = 257,
+			GETOPT_VAL_FORCE_DECOMPRESS,
+		};
 		static const struct option long_opts[] = {
 			{ "max-errors", required_argument, NULL, 'E' },
 			{ "chroot", no_argument, NULL, 'C' },
 			{ "dump", no_argument, NULL, GETOPT_VAL_DUMP },
 			{ "quiet", no_argument, NULL, 'q' },
+			{ "force-decompress", no_argument, NULL, GETOPT_VAL_FORCE_DECOMPRESS },
 			{ NULL, 0, NULL, 0 }
 		};
 
@@ -1330,6 +1575,9 @@ static int cmd_receive(const struct cmd_struct *cmd, int argc, char **argv)
 		case GETOPT_VAL_DUMP:
 			dump = 1;
 			break;
+		case GETOPT_VAL_FORCE_DECOMPRESS:
+			rctx.force_decompress = 1;
+			break;
 		default:
 			usage_unknown_option(cmd, argv);
 		}
-- 
2.32.0

[PATCH v10 07/10] btrfs-progs: receive: process fallocate commands

[Omar Sandoval]

From: Boris Burkov <boris@bur.io>

Send stream v2 can emit fallocate commands, so receive must support them
as well. The implementation simply passes along the arguments to the
syscall. Note that mode is encoded as a u32 in send stream but fallocate
takes an int, so there is a unsigned->signed conversion there.

Signed-off-by: Boris Burkov <boris@bur.io>
---
 cmds/receive-dump.c  |  9 +++++++++
 cmds/receive.c       | 25 +++++++++++++++++++++++++
 common/send-stream.c |  9 +++++++++
 common/send-stream.h |  2 ++
 4 files changed, 45 insertions(+)

diff --git a/cmds/receive-dump.c b/cmds/receive-dump.c
index 20ec2b70..acc0ba32 100644
--- a/cmds/receive-dump.c
+++ b/cmds/receive-dump.c
@@ -329,6 +329,14 @@ static int print_encoded_write(const char *path, const void *data, u64 offset,
 			  unencoded_offset, compression, encryption);
 }
 
+static int print_fallocate(const char *path, int mode, u64 offset, u64 len,
+			   void *user)
+{
+	return PRINT_DUMP(user, path, "fallocate",
+			  "mode=%d offset=%llu len=%llu",
+			  mode, offset, len);
+}
+
 struct btrfs_send_ops btrfs_print_send_ops = {
 	.subvol = print_subvol,
 	.snapshot = print_snapshot,
@@ -352,4 +360,5 @@ struct btrfs_send_ops btrfs_print_send_ops = {
 	.utimes = print_utimes,
 	.update_extent = print_update_extent,
 	.encoded_write = print_encoded_write,
+	.fallocate = print_fallocate,
 };
diff --git a/cmds/receive.c b/cmds/receive.c
index 7506f992..dd27af95 100644
--- a/cmds/receive.c
+++ b/cmds/receive.c
@@ -1264,6 +1264,30 @@ static int process_encoded_write(const char *path, const void *data, u64 offset,
 				    compression);
 }
 
+static int process_fallocate(const char *path, int mode, u64 offset, u64 len,
+			     void *user)
+{
+	int ret;
+	struct btrfs_receive *rctx = user;
+	char full_path[PATH_MAX];
+
+	ret = path_cat_out(full_path, rctx->full_subvol_path, path);
+	if (ret < 0) {
+		error("fallocate: path invalid: %s", path);
+		return ret;
+	}
+	ret = open_inode_for_write(rctx, full_path);
+	if (ret < 0)
+		return ret;
+	ret = fallocate(rctx->write_fd, mode, offset, len);
+	if (ret < 0) {
+		ret = -errno;
+		error("fallocate: fallocate on %s failed: %m", path);
+		return ret;
+	}
+	return 0;
+}
+
 static struct btrfs_send_ops send_ops = {
 	.subvol = process_subvol,
 	.snapshot = process_snapshot,
@@ -1287,6 +1311,7 @@ static struct btrfs_send_ops send_ops = {
 	.utimes = process_utimes,
 	.update_extent = process_update_extent,
 	.encoded_write = process_encoded_write,
+	.fallocate = process_fallocate,
 };
 
 static int do_receive(struct btrfs_receive *rctx, const char *tomnt,
diff --git a/common/send-stream.c b/common/send-stream.c
index 044e101b..bc41396e 100644
--- a/common/send-stream.c
+++ b/common/send-stream.c
@@ -369,6 +369,7 @@ static int read_and_process_cmd(struct btrfs_send_stream *sctx)
 	u64 unencoded_offset;
 	int len;
 	int xattr_len;
+	int fallocate_mode;
 
 	ret = read_cmd(sctx);
 	if (ret)
@@ -514,6 +515,14 @@ static int read_and_process_cmd(struct btrfs_send_stream *sctx)
 	case BTRFS_SEND_C_END:
 		ret = 1;
 		break;
+	case BTRFS_SEND_C_FALLOCATE:
+		TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
+		TLV_GET_U32(sctx, BTRFS_SEND_A_FALLOCATE_MODE, &fallocate_mode);
+		TLV_GET_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, &offset);
+		TLV_GET_U64(sctx, BTRFS_SEND_A_SIZE, &tmp);
+		ret = sctx->ops->fallocate(path, fallocate_mode, offset, tmp,
+					   sctx->user);
+		break;
 	}
 
 tlv_get_failed:
diff --git a/common/send-stream.h b/common/send-stream.h
index 607bc007..a58739bb 100644
--- a/common/send-stream.h
+++ b/common/send-stream.h
@@ -70,6 +70,8 @@ struct btrfs_send_ops {
 			     u64 len, u64 unencoded_file_len, u64 unencoded_len,
 			     u64 unencoded_offset, u32 compression,
 			     u32 encryption, void *user);
+	int (*fallocate)(const char *path, int mode, u64 offset, u64 len,
+			 void *user);
 };
 
 int btrfs_read_and_process_send_stream(int fd,
-- 
2.32.0

[PATCH v10 08/10] btrfs-progs: receive: process setflags ioctl commands

[Omar Sandoval]

From: Boris Burkov <boris@bur.io>

In send stream v2, send can emit a command for setting inode flags via
the setflags ioctl. Pass the flags attribute through to the ioctl call
in receive.

Signed-off-by: Boris Burkov <boris@bur.io>
---
 cmds/receive-dump.c  |  6 ++++++
 cmds/receive.c       | 25 +++++++++++++++++++++++++
 common/send-stream.c |  7 +++++++
 common/send-stream.h |  1 +
 4 files changed, 39 insertions(+)

diff --git a/cmds/receive-dump.c b/cmds/receive-dump.c
index acc0ba32..40f07ad4 100644
--- a/cmds/receive-dump.c
+++ b/cmds/receive-dump.c
@@ -337,6 +337,11 @@ static int print_fallocate(const char *path, int mode, u64 offset, u64 len,
 			  mode, offset, len);
 }
 
+static int print_setflags(const char *path, int flags, void *user)
+{
+	return PRINT_DUMP(user, path, "setflags", "flags=%d", flags);
+}
+
 struct btrfs_send_ops btrfs_print_send_ops = {
 	.subvol = print_subvol,
 	.snapshot = print_snapshot,
@@ -361,4 +366,5 @@ struct btrfs_send_ops btrfs_print_send_ops = {
 	.update_extent = print_update_extent,
 	.encoded_write = print_encoded_write,
 	.fallocate = print_fallocate,
+	.setflags = print_setflags,
 };
diff --git a/cmds/receive.c b/cmds/receive.c
index dd27af95..255e138c 100644
--- a/cmds/receive.c
+++ b/cmds/receive.c
@@ -38,6 +38,7 @@
 #include <sys/types.h>
 #include <sys/uio.h>
 #include <sys/xattr.h>
+#include <linux/fs.h>
 #include <uuid/uuid.h>
 
 #include <lzo/lzo1x.h>
@@ -1288,6 +1289,29 @@ static int process_fallocate(const char *path, int mode, u64 offset, u64 len,
 	return 0;
 }
 
+static int process_setflags(const char *path, int flags, void *user)
+{
+	int ret;
+	struct btrfs_receive *rctx = user;
+	char full_path[PATH_MAX];
+
+	ret = path_cat_out(full_path, rctx->full_subvol_path, path);
+	if (ret < 0) {
+		error("setflags: path invalid: %s", path);
+		return ret;
+	}
+	ret = open_inode_for_write(rctx, full_path);
+	if (ret < 0)
+		return ret;
+	ret = ioctl(rctx->write_fd, FS_IOC_SETFLAGS, &flags);
+	if (ret < 0) {
+		ret = -errno;
+		error("setflags: setflags ioctl on %s failed: %m", path);
+		return ret;
+	}
+	return 0;
+}
+
 static struct btrfs_send_ops send_ops = {
 	.subvol = process_subvol,
 	.snapshot = process_snapshot,
@@ -1312,6 +1336,7 @@ static struct btrfs_send_ops send_ops = {
 	.update_extent = process_update_extent,
 	.encoded_write = process_encoded_write,
 	.fallocate = process_fallocate,
+	.setflags = process_setflags,
 };
 
 static int do_receive(struct btrfs_receive *rctx, const char *tomnt,
diff --git a/common/send-stream.c b/common/send-stream.c
index bc41396e..b9d35a34 100644
--- a/common/send-stream.c
+++ b/common/send-stream.c
@@ -370,6 +370,7 @@ static int read_and_process_cmd(struct btrfs_send_stream *sctx)
 	int len;
 	int xattr_len;
 	int fallocate_mode;
+	int setflags_flags;
 
 	ret = read_cmd(sctx);
 	if (ret)
@@ -523,8 +524,14 @@ static int read_and_process_cmd(struct btrfs_send_stream *sctx)
 		ret = sctx->ops->fallocate(path, fallocate_mode, offset, tmp,
 					   sctx->user);
 		break;
+	case BTRFS_SEND_C_SETFLAGS:
+		TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
+		TLV_GET_U32(sctx, BTRFS_SEND_A_SETFLAGS_FLAGS, &setflags_flags);
+		ret = sctx->ops->setflags(path, setflags_flags, sctx->user);
+		break;
 	}
 
+
 tlv_get_failed:
 out:
 	free(path);
diff --git a/common/send-stream.h b/common/send-stream.h
index a58739bb..5373bf69 100644
--- a/common/send-stream.h
+++ b/common/send-stream.h
@@ -72,6 +72,7 @@ struct btrfs_send_ops {
 			     u32 encryption, void *user);
 	int (*fallocate)(const char *path, int mode, u64 offset, u64 len,
 			 void *user);
+	int (*setflags)(const char *path, int flags, void *user);
 };
 
 int btrfs_read_and_process_send_stream(int fd,
-- 
2.32.0

[PATCH v10 09/10] btrfs-progs: send: stream v2 ioctl flags

[Omar Sandoval]

From: Boris Burkov <boris@bur.io>

To make the btrfs send ioctl use the stream v2 format requires passing
BTRFS_SEND_FLAG_STREAM_V2 in flags. Further, to cause the ioctl to emit
encoded_write commands for encoded extents, we must set that flag as
well as BTRFS_SEND_FLAG_COMPRESSED. Finally, we bump up the version in
send.h as well, since we are now fully compatible with v2.

Add two command line arguments to btrfs send: --stream-version and
--compressed-data. --stream-version requires an argument which it parses
as an integer and sets STREAM_V2 if the argument is 2. --compressed-data
does not require an argument and automatically implies STREAM_V2 as well
(COMPRESSED alone causes the ioctl to error out).

Some examples to illustrate edge cases:

// v1, old format and no encoded_writes
btrfs send subvol
btrfs send --stream-version 1 subvol

// v2 and compressed, we will see encoded_writes
btrfs send --compressed-data subvol
btrfs send --compressed-data --stream-version 2 subvol

// v2 only, new format but no encoded_writes
btrfs send --stream-version 2 subvol

// error: compressed needs version >= 2
btrfs send --compressed-data --stream-version 1 subvol

// error: invalid version (not 1 or 2)
btrfs send --stream-version 3 subvol
btrfs send --compressed-data --stream-version 0 subvol
btrfs send --compressed-data --stream-version 10 subvol

Signed-off-by: Boris Burkov <boris@bur.io>
---
 Documentation/btrfs-send.asciidoc | 16 ++++++++-
 cmds/send.c                       | 54 ++++++++++++++++++++++++++++++-
 ioctl.h                           | 17 +++++++++-
 libbtrfsutil/btrfs.h              | 17 +++++++++-
 send.h                            |  2 +-
 5 files changed, 101 insertions(+), 5 deletions(-)

diff --git a/Documentation/btrfs-send.asciidoc b/Documentation/btrfs-send.asciidoc
index c4a05672..202bcd97 100644
--- a/Documentation/btrfs-send.asciidoc
+++ b/Documentation/btrfs-send.asciidoc
@@ -55,7 +55,21 @@ send in 'NO_FILE_DATA' mode
 The output stream does not contain any file
 data and thus cannot be used to transfer changes. This mode is faster and
 is useful to show the differences in metadata.
--q|--quiet::::
+
+--stream-version <1|2>::
+Use the given send stream version. The default is 1. Version 2 encodes file
+data slightly more efficiently; it is also required for sending compressed data
+directly (see '--compressed-data'). Version 2 requires at least btrfs-progs
+5.12 on both the sender and receiver and at least Linux 5.12 on the sender.
+
+--compressed-data::
+Send data that is compressed on the filesystem directly without decompressing
+it. If the receiver supports encoded I/O (see `encoded_io`(7)), it can also
+write it directly without decompressing it. Otherwise, the receiver will fall
+back to decompressing it and writing it normally. This implies
+'--stream-version 2'.
+
+-q|--quiet::
 (deprecated) alias for global '-q' option
 -v|--verbose::
 (deprecated) alias for global '-v' option
diff --git a/cmds/send.c b/cmds/send.c
index 3bfc69f5..80eb2510 100644
--- a/cmds/send.c
+++ b/cmds/send.c
@@ -452,6 +452,21 @@ static const char * const cmd_send_usage[] = {
 	"                 does not contain any file data and thus cannot be used",
 	"                 to transfer changes. This mode is faster and useful to",
 	"                 show the differences in metadata.",
+	"--stream-version <1|2>",
+	"                 Use the given send stream version. The default is",
+	"                 1. Version 2 encodes file data slightly more",
+	"                 efficiently; it is also required for sending",
+	"                 compressed data directly (see --compressed-data).",
+	"                 Version 2 requires at least btrfs-progs 5.12 on both",
+	"                 the sender and receiver and at least Linux 5.12 on the",
+	"                 sender.",
+	"--compressed-data",
+	"                 Send data that is compressed on the filesystem",
+	"                 directly without decompressing it. If the receiver",
+	"                 supports encoded I/O, it can also write it directly",
+	"                 without decompressing it. Otherwise, the receiver will",
+	"                 fall back to decompressing it and writing it normally.",
+	"                 This implies --stream-version 2.",
 	"-v|--verbose     deprecated, alias for global -v option",
 	"-q|--quiet       deprecated, alias for global -q option",
 	HELPINFO_INSERT_GLOBALS,
@@ -463,6 +478,7 @@ static const char * const cmd_send_usage[] = {
 static int cmd_send(const struct cmd_struct *cmd, int argc, char **argv)
 {
 	char *subvol = NULL;
+	char *end;
 	int ret;
 	char outname[PATH_MAX];
 	struct btrfs_send send;
@@ -474,6 +490,7 @@ static int cmd_send(const struct cmd_struct *cmd, int argc, char **argv)
 	int full_send = 1;
 	int new_end_cmd_semantic = 0;
 	u64 send_flags = 0;
+	long stream_version = 0;
 
 	memset(&send, 0, sizeof(send));
 	send.dump_fd = fileno(stdout);
@@ -492,11 +509,17 @@ static int cmd_send(const struct cmd_struct *cmd, int argc, char **argv)
 
 	optind = 0;
 	while (1) {
-		enum { GETOPT_VAL_SEND_NO_DATA = 256 };
+		enum {
+			GETOPT_VAL_SEND_NO_DATA = 256,
+			GETOPT_VAL_SEND_STREAM_V2,
+			GETOPT_VAL_SEND_COMPRESSED_DATA,
+		};
 		static const struct option long_options[] = {
 			{ "verbose", no_argument, NULL, 'v' },
 			{ "quiet", no_argument, NULL, 'q' },
 			{ "no-data", no_argument, NULL, GETOPT_VAL_SEND_NO_DATA },
+			{ "stream-version", required_argument, NULL, GETOPT_VAL_SEND_STREAM_V2 },
+			{ "compressed-data", no_argument, NULL, GETOPT_VAL_SEND_COMPRESSED_DATA },
 			{ NULL, 0, NULL, 0 }
 		};
 		int c = getopt_long(argc, argv, "vqec:f:i:p:", long_options, NULL);
@@ -585,10 +608,39 @@ static int cmd_send(const struct cmd_struct *cmd, int argc, char **argv)
 		case GETOPT_VAL_SEND_NO_DATA:
 			send_flags |= BTRFS_SEND_FLAG_NO_FILE_DATA;
 			break;
+		case GETOPT_VAL_SEND_STREAM_V2:
+			stream_version = strtol(optarg, &end, 10);
+			if (*end != '\0' ||
+			    stream_version < 1 || stream_version > 2) {
+				ret = 1;
+				error("invalid --stream-version. valid values: {1, 2}");
+				goto out;
+			}
+			if (stream_version == 2)
+				send_flags |= BTRFS_SEND_FLAG_STREAM_V2;
+			break;
+		case GETOPT_VAL_SEND_COMPRESSED_DATA:
+			send_flags |= BTRFS_SEND_FLAG_COMPRESSED;
+			/*
+			 * We want to default to stream v2 if only compressed is
+			 * set. If stream_version is explicitly set to 0, that
+			 * will trigger its own error condition for being an
+			 * invalid version.
+			 */
+			if (stream_version == 0) {
+				stream_version = 2;
+				send_flags |= BTRFS_SEND_FLAG_STREAM_V2;
+			}
+			break;
 		default:
 			usage_unknown_option(cmd, argv);
 		}
 	}
+	if (stream_version < 2 && (send_flags & BTRFS_SEND_FLAG_COMPRESSED)) {
+		ret = 1;
+		error("--compressed requires --stream-version >= 2");
+		goto out;
+	}
 
 	if (check_argc_min(argc - optind, 1))
 		return 1;
diff --git a/ioctl.h b/ioctl.h
index a472dbd2..005f00e5 100644
--- a/ioctl.h
+++ b/ioctl.h
@@ -653,10 +653,25 @@ BUILD_ASSERT(sizeof(struct btrfs_ioctl_received_subvol_args_32) == 192);
  */
 #define BTRFS_SEND_FLAG_OMIT_END_CMD		0x4
 
+/*
+ * Use version 2 of the send stream, which adds new commands and supports larger
+ * writes.
+ */
+#define BTRFS_SEND_FLAG_STREAM_V2		0x8
+
+/*
+ * Send compressed data using the ENCODED_WRITE command instead of decompressing
+ * the data and sending it with the WRITE command. This requires
+ * BTRFS_SEND_FLAG_STREAM_V2.
+ */
+#define BTRFS_SEND_FLAG_COMPRESSED		0x10
+
 #define BTRFS_SEND_FLAG_MASK \
 	(BTRFS_SEND_FLAG_NO_FILE_DATA | \
 	 BTRFS_SEND_FLAG_OMIT_STREAM_HEADER | \
-	 BTRFS_SEND_FLAG_OMIT_END_CMD)
+	 BTRFS_SEND_FLAG_OMIT_END_CMD | \
+	 BTRFS_SEND_FLAG_STREAM_V2 | \
+	 BTRFS_SEND_FLAG_COMPRESSED)
 
 struct btrfs_ioctl_send_args {
 	__s64 send_fd;			/* in */
diff --git a/libbtrfsutil/btrfs.h b/libbtrfsutil/btrfs.h
index a3117362..76022b7c 100644
--- a/libbtrfsutil/btrfs.h
+++ b/libbtrfsutil/btrfs.h
@@ -731,10 +731,25 @@ struct btrfs_ioctl_received_subvol_args {
  */
 #define BTRFS_SEND_FLAG_OMIT_END_CMD		0x4
 
+/*
+ * Use version 2 of the send stream, which adds new commands and supports larger
+ * writes.
+ */
+#define BTRFS_SEND_FLAG_STREAM_V2		0x8
+
+/*
+ * Send compressed data using the ENCODED_WRITE command instead of decompressing
+ * the data and sending it with the WRITE command. This requires
+ * BTRFS_SEND_FLAG_STREAM_V2.
+ */
+#define BTRFS_SEND_FLAG_COMPRESSED		0x10
+
 #define BTRFS_SEND_FLAG_MASK \
 	(BTRFS_SEND_FLAG_NO_FILE_DATA | \
 	 BTRFS_SEND_FLAG_OMIT_STREAM_HEADER | \
-	 BTRFS_SEND_FLAG_OMIT_END_CMD)
+	 BTRFS_SEND_FLAG_OMIT_END_CMD | \
+	 BTRFS_SEND_FLAG_STREAM_V2 | \
+	 BTRFS_SEND_FLAG_COMPRESSED)
 
 struct btrfs_ioctl_send_args {
 	__s64 send_fd;			/* in */
diff --git a/send.h b/send.h
index 3c47e0c7..fac90588 100644
--- a/send.h
+++ b/send.h
@@ -31,7 +31,7 @@ extern "C" {
 #endif
 
 #define BTRFS_SEND_STREAM_MAGIC "btrfs-stream"
-#define BTRFS_SEND_STREAM_VERSION 1
+#define BTRFS_SEND_STREAM_VERSION 2
 
 #define BTRFS_SEND_BUF_SIZE_V1 SZ_64K
 #define BTRFS_SEND_READ_SIZE (1024 * 48)
-- 
2.32.0

[PATCH v10 10/10] btrfs-progs: receive: add tests for basic encoded_write send/receive

[Omar Sandoval]

From: Boris Burkov <boris@bur.io>

Adapt the existing send/receive tests by passing '-o --force-compress'
to the mount commands in a new test. After writing a few files in the
various compression formats, send/receive them with and without
--force-decompress to test both the encoded_write path and the
fallback to decode+write.

Signed-off-by: Boris Burkov <boris@bur.io>
---
 .../049-receive-write-encoded/test.sh         | 114 ++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100755 tests/misc-tests/049-receive-write-encoded/test.sh

diff --git a/tests/misc-tests/049-receive-write-encoded/test.sh b/tests/misc-tests/049-receive-write-encoded/test.sh
new file mode 100755
index 00000000..b9390e88
--- /dev/null
+++ b/tests/misc-tests/049-receive-write-encoded/test.sh
@@ -0,0 +1,114 @@
+#!/bin/bash
+#
+# test that we can send and receive encoded writes for three modes of
+# transparent compression: zlib, lzo, and zstd.
+
+source "$TEST_TOP/common"
+
+check_prereq mkfs.btrfs
+check_prereq btrfs
+
+setup_root_helper
+prepare_test_dev
+
+here=`pwd`
+
+# assumes the filesystem exists, and does mount, write, snapshot, send, unmount
+# for the specified encoding option
+send_one() {
+	local str
+	local subv
+	local snap
+
+	algorithm="$1"
+	shift
+	str="$1"
+	shift
+
+	subv="subv-$algorithm"
+	snap="snap-$algorithm"
+
+	run_check_mount_test_dev "-o" "compress-force=$algorithm"
+	cd "$TEST_MNT" || _fail "cannot chdir to TEST_MNT"
+
+	run_check $SUDO_HELPER "$TOP/btrfs" subvolume create "$subv"
+	run_check $SUDO_HELPER dd if=/dev/zero of="$subv/file1" bs=1M count=1
+	run_check $SUDO_HELPER dd if=/dev/zero of="$subv/file2" bs=500K count=1
+	run_check $SUDO_HELPER "$TOP/btrfs" subvolume snapshot -r "$subv" "$snap"
+	run_check $SUDO_HELPER "$TOP/btrfs" send -f "$str" "$snap" "$@"
+
+	cd "$here" || _fail "cannot chdir back to test directory"
+	run_check_umount_test_dev
+}
+
+receive_one() {
+	local str
+	str="$1"
+	shift
+
+	run_check_mkfs_test_dev
+	run_check_mount_test_dev
+	run_check $SUDO_HELPER "$TOP/btrfs" receive "$@" -v -f "$str" "$TEST_MNT"
+	run_check_umount_test_dev
+	run_check rm -f -- "$str"
+}
+
+test_one_write_encoded() {
+	local str
+	local algorithm
+	algorithm="$1"
+	shift
+	str="$here/stream-$algorithm.stream"
+
+	run_check_mkfs_test_dev
+	send_one "$algorithm" "$str" --compressed-data
+	receive_one "$str" "$@"
+}
+
+test_one_stream_v1() {
+	local str
+	local algorithm
+	algorithm="$1"
+	shift
+	str="$here/stream-$algorithm.stream"
+
+	run_check_mkfs_test_dev
+	send_one "$algorithm" "$str" --stream-version 1
+	receive_one "$str" "$@"
+}
+
+test_mix_write_encoded() {
+	local strzlib
+	local strlzo
+	local strzstd
+	strzlib="$here/stream-zlib.stream"
+	strlzo="$here/stream-lzo.stream"
+	strzstd="$here/stream-zstd.stream"
+
+	run_check_mkfs_test_dev
+
+	send_one "zlib" "$strzlib" --compressed-data
+	send_one "lzo" "$strlzo" --compressed-data
+	send_one "zstd" "$strzstd" --compressed-data
+
+	receive_one "$strzlib"
+	receive_one "$strlzo"
+	receive_one "$strzstd"
+}
+
+test_one_write_encoded "zlib"
+test_one_write_encoded "lzo"
+test_one_write_encoded "zstd"
+
+# with decompression forced
+test_one_write_encoded "zlib" "--force-decompress"
+test_one_write_encoded "lzo" "--force-decompress"
+test_one_write_encoded "zstd" "--force-decompress"
+
+# send stream v1
+test_one_stream_v1 "zlib"
+test_one_stream_v1 "lzo"
+test_one_stream_v1 "zstd"
+
+# files use a mix of compression algorithms
+test_mix_write_encoded
-- 
2.32.0

Re: [PATCH v10 06/10] btrfs-progs: receive: encoded_write fallback to explicit decode and write

[Omar Sandoval]

On Tue, Aug 17, 2021 at 02:06:52PM -0700, Omar Sandoval wrote:
> From: Boris Burkov <boris@bur.io>
> 
> An encoded_write can fail if the file system it is being applied to does
> not support encoded writes or if it can't find enough contiguous space
> to accommodate the encoded extent. In those cases, we can likely still
> process an encoded_write by explicitly decoding the data and doing a
> normal write.
> 
> Add the necessary fallback path for decoding data compressed with zlib,
> lzo, or zstd. zlib and zstd have reusable decoding context data
> structures which we cache in the receive context so that we don't have
> to recreate them on every encoded_write.
> 
> Finally, add a command line flag for force-decompress which causes
> receive to always use the fallback path rather than first attempting the
> encoded write.
> 
> Signed-off-by: Boris Burkov <boris@bur.io>
> ---
>  Documentation/btrfs-receive.asciidoc |   4 +
>  cmds/receive.c                       | 266 ++++++++++++++++++++++++++-
>  2 files changed, 261 insertions(+), 9 deletions(-)
> 
> diff --git a/Documentation/btrfs-receive.asciidoc b/Documentation/btrfs-receive.asciidoc
> index e4c4d2c0..354a71dc 100644
> --- a/Documentation/btrfs-receive.asciidoc
> +++ b/Documentation/btrfs-receive.asciidoc
> @@ -60,6 +60,10 @@ By default the mountpoint is searched in '/proc/self/mounts'.
>  If '/proc' is not accessible, eg. in a chroot environment, use this option to
>  tell us where this filesystem is mounted.
>  
> +--force-decompress::
> +if the stream contains compressed data (see '--compressed-data' in
> +`btrfs-send`(8)), always decompress it instead of writing it with encoded I/O.
> +
>  --dump::
>  dump the stream metadata, one line per operation
>  +
> diff --git a/cmds/receive.c b/cmds/receive.c
> index b43c298f..7506f992 100644
> --- a/cmds/receive.c
> +++ b/cmds/receive.c
> @@ -40,6 +40,10 @@
>  #include <sys/xattr.h>
>  #include <uuid/uuid.h>
>  
> +#include <lzo/lzo1x.h>
> +#include <zlib.h>
> +#include <zstd.h>
> +
>  #include "kernel-shared/ctree.h"
>  #include "ioctl.h"
>  #include "cmds/commands.h"
> @@ -79,6 +83,12 @@ struct btrfs_receive
>  	struct subvol_uuid_search sus;
>  
>  	int honor_end_cmd;
> +
> +	int force_decompress;
> +
> +	/* Reuse stream objects for encoded_write decompression fallback */
> +	ZSTD_DStream *zstd_dstream;
> +	z_stream *zlib_stream;
>  };
>  
>  static int finish_subvol(struct btrfs_receive *rctx)
> @@ -989,9 +999,222 @@ static int process_update_extent(const char *path, u64 offset, u64 len,
>  	return 0;
>  }
>  
> +static int decompress_zlib(struct btrfs_receive *rctx, const char *encoded_data,
> +			   u64 encoded_len, char *unencoded_data,
> +			   u64 unencoded_len)
> +{
> +	bool init = false;
> +	int ret;
> +
> +	if (!rctx->zlib_stream) {
> +		init = true;
> +		rctx->zlib_stream = malloc(sizeof(z_stream));
> +		if (!rctx->zlib_stream) {
> +			error("failed to allocate zlib stream %m");
> +			return -ENOMEM;
> +		}
> +	}
> +	rctx->zlib_stream->next_in = (void *)encoded_data;
> +	rctx->zlib_stream->avail_in = encoded_len;
> +	rctx->zlib_stream->next_out = (void *)unencoded_data;
> +	rctx->zlib_stream->avail_out = unencoded_len;
> +
> +	if (init) {
> +		rctx->zlib_stream->zalloc = Z_NULL;
> +		rctx->zlib_stream->zfree = Z_NULL;
> +		rctx->zlib_stream->opaque = Z_NULL;
> +		ret = inflateInit(rctx->zlib_stream);
> +	} else {
> +		ret = inflateReset(rctx->zlib_stream);
> +	}
> +	if (ret != Z_OK) {
> +		error("zlib inflate init failed: %d", ret);
> +		return -EIO;
> +	}
> +
> +	while (rctx->zlib_stream->avail_in > 0 &&
> +	       rctx->zlib_stream->avail_out > 0) {
> +		ret = inflate(rctx->zlib_stream, Z_FINISH);
> +		if (ret == Z_STREAM_END) {
> +			break;
> +		} else if (ret != Z_OK) {
> +			error("zlib inflate failed: %d", ret);
> +			return -EIO;
> +		}
> +	}
> +	return 0;
> +}
> +
> +static int decompress_zstd(struct btrfs_receive *rctx, const char *encoded_buf,
> +			   u64 encoded_len, char *unencoded_buf,
> +			   u64 unencoded_len)
> +{
> +	ZSTD_inBuffer in_buf = {
> +		.src = encoded_buf,
> +		.size = encoded_len
> +	};
> +	ZSTD_outBuffer out_buf = {
> +		.dst = unencoded_buf,
> +		.size = unencoded_len
> +	};
> +	size_t ret;
> +
> +	if (!rctx->zstd_dstream) {
> +		rctx->zstd_dstream = ZSTD_createDStream();
> +		if (!rctx->zstd_dstream) {
> +			error("failed to create zstd dstream");
> +			return -ENOMEM;
> +		}
> +	}
> +	ret = ZSTD_initDStream(rctx->zstd_dstream);
> +	if (ZSTD_isError(ret)) {
> +		error("failed to init zstd stream: %s", ZSTD_getErrorName(ret));
> +		return -EIO;
> +	}
> +	while (in_buf.pos < in_buf.size && out_buf.pos < out_buf.size) {
> +		ret = ZSTD_decompressStream(rctx->zstd_dstream, &out_buf, &in_buf);
> +		if (ret == 0) {
> +			break;
> +		} else if (ZSTD_isError(ret)) {
> +			error("failed to decompress zstd stream: %s",
> +			      ZSTD_getErrorName(ret));
> +			return -EIO;
> +		}
> +	}
> +	return 0;
> +}
> +
> +static int decompress_lzo(const char *encoded_data, u64 encoded_len,
> +			  char *unencoded_data, u64 unencoded_len,
> +			  unsigned int page_size)
> +{
> +	uint32_t total_len;
> +	size_t in_pos, out_pos;
> +
> +	if (encoded_len < 4) {
> +		error("lzo header is truncated");
> +		return -EIO;
> +	}
> +	memcpy(&total_len, encoded_data, 4);
> +	total_len = le32toh(total_len);
> +	if (total_len > encoded_len) {
> +		error("lzo header is invalid");
> +		return -EIO;
> +	}
> +
> +	in_pos = 4;
> +	out_pos = 0;
> +	while (in_pos < total_len && out_pos < unencoded_len) {
> +		size_t page_remaining;
> +		uint32_t src_len;
> +		lzo_uint dst_len;
> +		int ret;
> +
> +		page_remaining = -in_pos % page_size;
> +		if (page_remaining < 4) {
> +			if (total_len - in_pos <= page_remaining)
> +				break;
> +			in_pos += page_remaining;
> +		}
> +
> +		if (total_len - in_pos < 4) {
> +			error("lzo segment header is truncated");
> +			return -EIO;
> +		}
> +
> +		memcpy(&src_len, encoded_data + in_pos, 4);
> +		src_len = le32toh(src_len);
> +		in_pos += 4;
> +		if (src_len > total_len - in_pos) {
> +			error("lzo segment header is invalid");
> +			return -EIO;
> +		}
> +
> +		dst_len = page_size;
> +		ret = lzo1x_decompress_safe((void *)(encoded_data + in_pos),
> +					    src_len,
> +					    (void *)(unencoded_data + out_pos),
> +					    &dst_len, NULL);
> +		if (ret != LZO_E_OK) {
> +			error("lzo1x_decompress_safe failed: %d", ret);
> +			return -EIO;
> +		}
> +
> +		in_pos += src_len;
> +		out_pos += dst_len;
> +	}
> +	return 0;
> +}
> +
> +static int decompress_and_write(struct btrfs_receive *rctx,
> +				const char *encoded_data, u64 offset,
> +				u64 encoded_len, u64 unencoded_file_len,
> +				u64 unencoded_len, u64 unencoded_offset,
> +				u32 compression)
> +{
> +	int ret = 0;
> +	size_t pos;
> +	ssize_t w;
> +	char *unencoded_data;
> +	int page_shift;
> +
> +	unencoded_data = calloc(unencoded_len, 1);
> +	if (!unencoded_data) {
> +		error("allocating space for unencoded data failed: %m");
> +		return -errno;
> +	}
> +
> +	switch (compression) {
> +	case BTRFS_ENCODED_IO_COMPRESSION_ZLIB:
> +		ret = decompress_zlib(rctx, encoded_data, encoded_len,
> +				      unencoded_data, unencoded_len);
> +		if (ret)
> +			goto out;
> +		break;
> +	case BTRFS_ENCODED_IO_COMPRESSION_ZSTD:
> +		ret = decompress_zstd(rctx, encoded_data, encoded_len,
> +				      unencoded_data, unencoded_len);
> +		if (ret)
> +			goto out;
> +		break;
> +	case BTRFS_ENCODED_IO_COMPRESSION_LZO_4K:
> +	case BTRFS_ENCODED_IO_COMPRESSION_LZO_8K:
> +	case BTRFS_ENCODED_IO_COMPRESSION_LZO_16K:
> +	case BTRFS_ENCODED_IO_COMPRESSION_LZO_32K:
> +	case BTRFS_ENCODED_IO_COMPRESSION_LZO_64K:
> +		page_shift = compression - BTRFS_ENCODED_IO_COMPRESSION_LZO_4K + 12;
> +		ret = decompress_lzo(encoded_data, encoded_len, unencoded_data,
> +				     unencoded_len, 1U << page_shift);
> +		if (ret)
> +			goto out;
> +		break;
> +	default:
> +		error("unknown compression: %d", compression);
> +		ret = -EOPNOTSUPP;
> +		goto out;
> +	}
> +
> +	pos = unencoded_offset;
> +	while (pos < unencoded_file_len) {
> +		w = pwrite(rctx->write_fd, unencoded_data + pos,
> +			   unencoded_file_len - pos, offset);
> +		if (w < 0) {
> +			ret = -errno;
> +			error("writing unencoded data failed: %m");
> +			goto out;
> +		}
> +		pos += w;
> +		offset += w;
> +	}
> +out:
> +	free(unencoded_data);
> +	return ret;
> +}
> +
>  static int process_encoded_write(const char *path, const void *data, u64 offset,
> -	u64 len, u64 unencoded_file_len, u64 unencoded_len,
> -	u64 unencoded_offset, u32 compression, u32 encryption, void *user)
> +				 u64 len, u64 unencoded_file_len,
> +				 u64 unencoded_len, u64 unencoded_offset,
> +				 u32 compression, u32 encryption, void *user)
>  {
>  	int ret;
>  	struct btrfs_receive *rctx = user;
> @@ -1007,6 +1230,7 @@ static int process_encoded_write(const char *path, const void *data, u64 offset,
>  		.compression = compression,
>  		.encryption = encryption,
>  	};
> +	bool encoded_write = !rctx->force_decompress;
>  
>  	if (encryption) {
>  		error("encoded_write: encryption not supported");
> @@ -1023,13 +1247,21 @@ static int process_encoded_write(const char *path, const void *data, u64 offset,
>  	if (ret < 0)
>  		return ret;
>  
> -	ret = ioctl(rctx->write_fd, BTRFS_IOC_ENCODED_WRITE, &encoded);
> -	if (ret < 0) {
> -		ret = -errno;
> -		error("encoded_write: writing to %s failed: %m", path);
> -		return ret;
> +	if (encoded_write) {
> +		ret = ioctl(rctx->write_fd, BTRFS_IOC_ENCODED_WRITE, &encoded);
> +		if (ret >= 0)
> +			return 0;
> +		/* Fall back for these errors, fail hard for anything else. */
> +		if (errno != ENOSPC && errno != EOPNOTSUPP && errno != EINVAL) {

Just caught something that I missed in the conversion, this needs to be
ENOTTY instead of EOPNOTSUPP.

Re: [PATCH v10 02/14] fs: export variant of generic_write_checks without iov_iter

[Nikolay Borisov]

On 18.08.21 г. 0:06, Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
> 
> Encoded I/O in Btrfs needs to check a write with a given logical size
> without an iov_iter that matches that size (because the iov_iter we have
> is for the compressed data). So, factor out the parts of
> generic_write_check() that expect an iov_iter into a new
> __generic_write_checks() function and export that.
> 
> Signed-off-by: Omar Sandoval <osandov@fb.com>
> ---
>  fs/read_write.c    | 40 ++++++++++++++++++++++------------------
>  include/linux/fs.h |  1 +
>  2 files changed, 23 insertions(+), 18 deletions(-)
> 
> diff --git a/fs/read_write.c b/fs/read_write.c
> index 0029ff2b0ca8..3bddd5ee7f64 100644
> --- a/fs/read_write.c
> +++ b/fs/read_write.c
> @@ -1633,6 +1633,26 @@ int generic_write_check_limits(struct file *file, loff_t pos, loff_t *count)
>  	return 0;
>  }
>  
> +/* Like generic_write_checks(), but takes size of write instead of iter. */
> +int __generic_write_checks(struct kiocb *iocb, loff_t *count)
> +{
> +	struct file *file = iocb->ki_filp;
> +	struct inode *inode = file->f_mapping->host;
> +
> +	if (IS_SWAPFILE(inode))
> +		return -ETXTBSY;

 Missing 'if(!count) return 0' from original code ?

<snip>

Re: [PATCH v10 03/14] btrfs: don't advance offset for compressed bios in btrfs_csum_one_bio()

[Nikolay Borisov]

On 18.08.21 г. 0:06, Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
> 
> btrfs_csum_one_bio() loops over each filesystem block in the bio while
> keeping a cursor of its current logical position in the file in order to
> look up the ordered extent to add the checksums to. However, this
> doesn't make much sense for compressed extents, as a sector on disk does
> not correspond to a sector of decompressed file data. It happens to work
> because 1) the compressed bio always covers one ordered extent and 2)
> the size of the bio is always less than the size of the ordered extent.
> However, the second point will not always be true for encoded writes.
> 
> Let's add a boolean parameter to btrfs_csum_one_bio() to indicate that
> it can assume that the bio only covers one ordered extent. Since we're
> already changing the signature, let's get rid of the contig parameter
> and make it implied by the offset parameter, similar to the change we
> recently made to btrfs_lookup_bio_sums(). Additionally, let's rename
> nr_sectors to blockcount to make it clear that it's the number of
> filesystem blocks, not the number of 512-byte sectors.
> 
> Reviewed-by: Josef Bacik <josef@toxicpanda.com>
> Signed-off-by: Omar Sandoval <osandov@fb.com>
> ---
>  fs/btrfs/compression.c |  5 +++--
>  fs/btrfs/ctree.h       |  2 +-
>  fs/btrfs/file-item.c   | 35 ++++++++++++++++-------------------
>  fs/btrfs/inode.c       |  8 ++++----
>  4 files changed, 24 insertions(+), 26 deletions(-)
> 
> diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
> index 7869ad12bc6e..e645b3c2f09a 100644
> --- a/fs/btrfs/compression.c
> +++ b/fs/btrfs/compression.c
> @@ -480,7 +480,8 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
>  			BUG_ON(ret); /* -ENOMEM */
>  
>  			if (!skip_sum) {
> -				ret = btrfs_csum_one_bio(inode, bio, start, 1);
> +				ret = btrfs_csum_one_bio(inode, bio, start,
> +							 true);
>  				BUG_ON(ret); /* -ENOMEM */
>  			}
>  
> @@ -516,7 +517,7 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
>  	BUG_ON(ret); /* -ENOMEM */
>  
>  	if (!skip_sum) {
> -		ret = btrfs_csum_one_bio(inode, bio, start, 1);
> +		ret = btrfs_csum_one_bio(inode, bio, start, true);
>  		BUG_ON(ret); /* -ENOMEM */
>  	}
>  
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index f07c82fafa04..be245b4b8efe 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -3111,7 +3111,7 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
>  			   struct btrfs_root *root,
>  			   struct btrfs_ordered_sum *sums);
>  blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
> -				u64 file_start, int contig);
> +				u64 offset, bool one_ordered);
>  int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
>  			     struct list_head *list, int search_commit);
>  void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
> diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
> index 2673c6ba7a4e..844fae923340 100644
> --- a/fs/btrfs/file-item.c
> +++ b/fs/btrfs/file-item.c
> @@ -614,28 +614,28 @@ int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
>   * btrfs_csum_one_bio - Calculates checksums of the data contained inside a bio
>   * @inode:	 Owner of the data inside the bio
>   * @bio:	 Contains the data to be checksummed
> - * @file_start:  offset in file this bio begins to describe
> - * @contig:	 Boolean. If true/1 means all bio vecs in this bio are
> - *		 contiguous and they begin at @file_start in the file. False/0
> - *		 means this bio can contain potentially discontiguous bio vecs
> - *		 so the logical offset of each should be calculated separately.
> + * @offset:      If (u64)-1, @bio may contain discontiguous bio vecs, so the
> + *               file offsets are determined from the page offsets in the bio.
> + *               Otherwise, this is the starting file offset of the bio vecs in
> + *               @bio, which must be contiguous.
> + * @one_ordered: If true, @bio only refers to one ordered extent.

nit: I don't have strong preference but my gut feeling tells me
"single_ordered" might be more explicit/informative. But unless someone
else thinks the same one_ordered would also make do

>   */
>  blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
> -		       u64 file_start, int contig)
> +				u64 offset, bool one_ordered)
>  {
>  	struct btrfs_fs_info *fs_info = inode->root->fs_info;
>  	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
>  	struct btrfs_ordered_sum *sums;
>  	struct btrfs_ordered_extent *ordered = NULL;
> +	const bool page_offsets = (offset == (u64)-1);

nit: Again, instead of page_offsets perhaps use_page_offsets, somewhat
more explicit/informative.

>  	char *data;
>  	struct bvec_iter iter;
>  	struct bio_vec bvec;
>  	int index;
> -	int nr_sectors;
> +	int blockcount;
>  	unsigned long total_bytes = 0;
>  	unsigned long this_sum_bytes = 0;
>  	int i;
> -	u64 offset;
>  	unsigned nofs_flag;
>  
>  	nofs_flag = memalloc_nofs_save();
> @@ -649,18 +649,13 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
>  	sums->len = bio->bi_iter.bi_size;
>  	INIT_LIST_HEAD(&sums->list);
>  
> -	if (contig)
> -		offset = file_start;
> -	else
> -		offset = 0; /* shut up gcc */
> -
>  	sums->bytenr = bio->bi_iter.bi_sector << 9;
>  	index = 0;
>  
>  	shash->tfm = fs_info->csum_shash;
>  
>  	bio_for_each_segment(bvec, bio, iter) {
> -		if (!contig)
> +		if (page_offsets)
>  			offset = page_offset(bvec.bv_page) + bvec.bv_offset;
>  
>  		if (!ordered) {
> @@ -668,13 +663,14 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
>  			BUG_ON(!ordered); /* Logic error */
>  		}
>  
> -		nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info,
> +		blockcount = BTRFS_BYTES_TO_BLKS(fs_info,
>  						 bvec.bv_len + fs_info->sectorsize
>  						 - 1);
>  
> -		for (i = 0; i < nr_sectors; i++) {
> -			if (offset >= ordered->file_offset + ordered->num_bytes ||
> -			    offset < ordered->file_offset) {
> +		for (i = 0; i < blockcount; i++) {
> +			if (!one_ordered &&
> +			    (offset >= ordered->file_offset + ordered->num_bytes ||
> +			     offset < ordered->file_offset)) {

Since you are changing this hunk, how about using the in_range macro:

if (!one_ordered && !in_range(offset, ordered->file_offset,
ordered->num_bytes) { foo

Though I think the "change the ordered extent now that we are working on
a different range" code should be factored out in a separate function
because currently it's somewhat breaking the flow of reading.

>  				unsigned long bytes_left;
>  
>  				sums->len = this_sum_bytes;
> @@ -705,7 +701,8 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
>  					    sums->sums + index);
>  			kunmap_atomic(data);
>  			index += fs_info->csum_size;
> -			offset += fs_info->sectorsize;
> +			if (!one_ordered)
> +				offset += fs_info->sectorsize;

Instead of adding one additional conditional op can't offset always be
incremented but in the case of one_ordered then the !in_range check
should always be false i.e we won't be using the offset to lookup a new OE?

>  			this_sum_bytes += fs_info->sectorsize;
>  			total_bytes += fs_info->sectorsize;
>  		}


<snip>

Re: [PATCH v10 04/14] btrfs: add ram_bytes and offset to btrfs_ordered_extent

[Nikolay Borisov]

On 18.08.21 г. 0:06, Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
> 
> Currently, we only create ordered extents when ram_bytes == num_bytes
> and offset == 0. However, RWF_ENCODED writes may create extents which
> only refer to a subset of the full unencoded extent, so we need to plumb

Can you give an example of such a case?

Re: [PATCH v10 06/14] btrfs: optionally extend i_size in cow_file_range_inline()

[Nikolay Borisov]

On 18.08.21 г. 0:06, Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
> 
> Currently, an inline extent is always created after i_size is extended
> from btrfs_dirty_pages(). However, for encoded writes, we only want to
> update i_size after we successfully created the inline extent. Add an
> update_i_size parameter to cow_file_range_inline() and
> insert_inline_extent() and pass in the size of the extent rather than
> determining it from i_size. Since the start parameter is always passed
> as 0, get rid of it and simplify the logic in these two functions. While
> we're here, let's document the requirements for creating an inline
> extent.
> 
> Reviewed-by: Josef Bacik <josef@toxicpanda.com>
> Signed-off-by: Omar Sandoval <osandov@fb.com>
> ---
>  fs/btrfs/inode.c | 100 +++++++++++++++++++++++------------------------
>  1 file changed, 48 insertions(+), 52 deletions(-)
> 
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 708d8ab098bc..0b5ff14aa7fd 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -236,9 +236,10 @@ static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
>  static int insert_inline_extent(struct btrfs_trans_handle *trans,
>  				struct btrfs_path *path, bool extent_inserted,
>  				struct btrfs_root *root, struct inode *inode,
> -				u64 start, size_t size, size_t compressed_size,
> +				size_t size, size_t compressed_size,
>  				int compress_type,
> -				struct page **compressed_pages)
> +				struct page **compressed_pages,
> +				bool update_i_size)
>  {
>  	struct extent_buffer *leaf;
>  	struct page *page = NULL;
> @@ -247,7 +248,7 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
>  	struct btrfs_file_extent_item *ei;
>  	int ret;
>  	size_t cur_size = size;
> -	unsigned long offset;
> +	u64 i_size;
>  
>  	ASSERT((compressed_size > 0 && compressed_pages) ||
>  	       (compressed_size == 0 && !compressed_pages));
> @@ -260,7 +261,7 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
>  		size_t datasize;
>  
>  		key.objectid = btrfs_ino(BTRFS_I(inode));
> -		key.offset = start;
> +		key.offset = 0;
>  		key.type = BTRFS_EXTENT_DATA_KEY;
>  
>  		datasize = btrfs_file_extent_calc_inline_size(cur_size);
> @@ -297,12 +298,10 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
>  		btrfs_set_file_extent_compression(leaf, ei,
>  						  compress_type);
>  	} else {
> -		page = find_get_page(inode->i_mapping,
> -				     start >> PAGE_SHIFT);
> +		page = find_get_page(inode->i_mapping, 0);
>  		btrfs_set_file_extent_compression(leaf, ei, 0);
>  		kaddr = kmap_atomic(page);
> -		offset = offset_in_page(start);
> -		write_extent_buffer(leaf, kaddr + offset, ptr, size);
> +		write_extent_buffer(leaf, kaddr, ptr, size);
>  		kunmap_atomic(kaddr);
>  		put_page(page);
>  	}
> @@ -313,8 +312,8 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
>  	 * We align size to sectorsize for inline extents just for simplicity
>  	 * sake.
>  	 */
> -	size = ALIGN(size, root->fs_info->sectorsize);
> -	ret = btrfs_inode_set_file_extent_range(BTRFS_I(inode), start, size);
> +	ret = btrfs_inode_set_file_extent_range(BTRFS_I(inode), 0,
> +					ALIGN(size, root->fs_info->sectorsize));
>  	if (ret)
>  		goto fail;
>  
> @@ -327,7 +326,13 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
>  	 * before we unlock the pages.  Otherwise we
>  	 * could end up racing with unlink.
>  	 */
> -	BTRFS_I(inode)->disk_i_size = inode->i_size;
> +	i_size = i_size_read(inode);
> +	if (update_i_size && size > i_size) {
> +		i_size_write(inode, size);
> +		i_size = size;
> +	}
> +	BTRFS_I(inode)->disk_i_size = i_size;
> +
>  fail:
>  	return ret;
>  }
> @@ -338,35 +343,31 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
>   * does the checks required to make sure the data is small enough
>   * to fit as an inline extent.
>   */
> -static noinline int cow_file_range_inline(struct btrfs_inode *inode, u64 start,
> -					  u64 end, size_t compressed_size,
> +static noinline int cow_file_range_inline(struct btrfs_inode *inode, u64 size,
> +					  size_t compressed_size,
>  					  int compress_type,
> -					  struct page **compressed_pages)
> +					  struct page **compressed_pages,
> +					  bool update_i_size)
>  {
>  	struct btrfs_drop_extents_args drop_args = { 0 };
>  	struct btrfs_root *root = inode->root;
>  	struct btrfs_fs_info *fs_info = root->fs_info;
>  	struct btrfs_trans_handle *trans;
> -	u64 isize = i_size_read(&inode->vfs_inode);
> -	u64 actual_end = min(end + 1, isize);
> -	u64 inline_len = actual_end - start;
> -	u64 aligned_end = ALIGN(end, fs_info->sectorsize);
> -	u64 data_len = inline_len;
> +	u64 data_len = compressed_size ? compressed_size : size;
>  	int ret;
>  	struct btrfs_path *path;
>  
> -	if (compressed_size)
> -		data_len = compressed_size;
> -
> -	if (start > 0 ||
> -	    actual_end > fs_info->sectorsize ||
> +	/*
> +	 * We can create an inline extent if it ends at or beyond the current
> +	 * i_size, is no larger than a sector (decompressed), and the (possibly
> +	 * compressed) data fits in a leaf and the configured maximum inline
> +	 * size.
> +	 */

Urgh, just some days ago Qu was talking about how awkward it is to have
mixed extents in a file. And now, AFAIU, you are making them more likely
since now they can be created not just at the beginning of the file but
also after i_size write. While this won't be a problem in and of itself
it goes just the opposite way of us trying to shrink the possible cases
when we can have mixed extents. Qu what is your take on that?

<snip>

Re: [PATCH v10 07/14] btrfs: add definitions + documentation for encoded I/O ioctls

[Nikolay Borisov]

On 18.08.21 г. 0:06, Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
> 
> In order to allow sending and receiving compressed data without
> decompressing it, we need an interface to write pre-compressed data
> directly to the filesystem and the matching interface to read compressed
> data without decompressing it. This adds the definitions for ioctls to
> do that and detailed explanations of how to use them.
> 
> Signed-off-by: Omar Sandoval <osandov@fb.com>
> ---
>  include/uapi/linux/btrfs.h | 132 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 132 insertions(+)
> 
> diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
> index d7d3cfead056..95da52955894 100644
> --- a/include/uapi/linux/btrfs.h
> +++ b/include/uapi/linux/btrfs.h
> @@ -861,6 +861,134 @@ struct btrfs_ioctl_get_subvol_rootref_args {
>  		__u8 align[7];
>  };
>  
> +/*
> + * Data and metadata for an encoded read or write.
> + *
> + * Encoded I/O bypasses any encoding automatically done by the filesystem (e.g.,
> + * compression). This can be used to read the compressed contents of a file or
> + * write pre-compressed data directly to a file.
> + *
> + * BTRFS_IOC_ENCODED_READ and BTRFS_IOC_ENCODED_WRITE are essentially
> + * preadv/pwritev with additional metadata about how the data is encoded and the
> + * size of the unencoded data.
> + *
> + * BTRFS_IOC_ENCODED_READ fills the given iovecs with the encoded data, fills
> + * the metadata fields, and returns the size of the encoded data. It reads one
> + * extent per call. It can also read data which is not encoded.
> + *
> + * BTRFS_IOC_ENCODED_WRITE uses the metadata fields, writes the encoded data
> + * from the iovecs, and returns the size of the encoded data. Note that the
> + * encoded data is not validated when it is written; if it is not valid (e.g.,
> + * it cannot be decompressed), then a subsequent read may return an error.
> + *
> + * Since the filesystem page cache contains decoded data, encoded I/O bypasses
> + * the page cache. Encoded I/O requires CAP_SYS_ADMIN.
> + */
> +struct btrfs_ioctl_encoded_io_args {
> +	/* Input parameters for both reads and writes. */
> +
> +	/*
> +	 * iovecs containing encoded data.
> +	 *
> +	 * For reads, if the size of the encoded data is larger than the sum of
> +	 * iov[n].iov_len for 0 <= n < iovcnt, then the ioctl fails with
> +	 * ENOBUFS.
> +	 *
> +	 * For writes, the size of the encoded data is the sum of iov[n].iov_len
> +	 * for 0 <= n < iovcnt. This must be less than 128 KiB (this limit may
> +	 * increase in the future). This must also be less than or equal to
> +	 * unencoded_len.
> +	 */
> +	const struct iovec __user *iov;
> +	/* Number of iovecs. */
> +	unsigned long iovcnt;
> +	/*
> +	 * Offset in file.
> +	 *
> +	 * For writes, must be aligned to the sector size of the filesystem.
> +	 */
> +	__s64 offset;
> +	/* Currently must be zero. */
> +	__u64 flags;
> +
> +	/*
> +	 * For reads, the following members are filled in with the metadata for
> +	 * the encoded data.
> +	 * For writes, the following members must be set to the metadata for the
> +	 * encoded data.
> +	 */
> +
> +	/*
> +	 * Length of the data in the file.
> +	 *
> +	 * Must be less than or equal to unencoded_len - unencoded_offset. For
> +	 * writes, must be aligned to the sector size of the filesystem unless
> +	 * the data ends at or beyond the current end of the file.
> +	 */
> +	__u64 len;
> +	/*
> +	 * Length of the unencoded (i.e., decrypted and decompressed) data.
> +	 *
> +	 * For writes, must be no more than 128 KiB (this limit may increase in
> +	 * the future). If the unencoded data is actually longer than
> +	 * unencoded_len, then it is truncated; if it is shorter, then it is
> +	 * extended with zeroes.
> +	 */
> +	__u64 unencoded_len;
> +	/*
> +	 * Offset from the first byte of the unencoded data to the first byte of
> +	 * logical data in the file.
> +	 *
> +	 * Must be less than unencoded_len.
> +	 */
> +	__u64 unencoded_offset;
> +	/*
> +	 * BTRFS_ENCODED_IO_COMPRESSION_* type.
> +	 *
> +	 * For writes, must not be BTRFS_ENCODED_IO_COMPRESSION_NONE.
> +	 */
> +	__u32 compression;
> +	/* Currently always BTRFS_ENCODED_IO_ENCRYPTION_NONE. */
> +	__u32 encryption;
> +	/*
> +	 * Reserved for future expansion.
> +	 *
> +	 * For reads, always returned as zero. Users should check for non-zero
> +	 * bytes. If there are any, then the kernel has a newer version of this
> +	 * structure with additional information that the user definition is
> +	 * missing.
> +	 *
> +	 * For writes, must be zeroed.
> +	 */
> +	__u8 reserved[32];
> +};
> +
> +/* Data is not compressed. */
> +#define BTRFS_ENCODED_IO_COMPRESSION_NONE 0
> +/* Data is compressed as a single zlib stream. */
> +#define BTRFS_ENCODED_IO_COMPRESSION_ZLIB 1
> +/*
> + * Data is compressed as a single zstd frame with the windowLog compression
> + * parameter set to no more than 17.
> + */
> +#define BTRFS_ENCODED_IO_COMPRESSION_ZSTD 2
> +/*
> + * Data is compressed page by page (using the page size indicated by the name of
> + * the constant) with LZO1X and wrapped in the format documented in
> + * fs/btrfs/lzo.c. For writes, the compression page size must match the
> + * filesystem page size.
> + */
> +#define BTRFS_ENCODED_IO_COMPRESSION_LZO_4K 3
> +#define BTRFS_ENCODED_IO_COMPRESSION_LZO_8K 4
> +#define BTRFS_ENCODED_IO_COMPRESSION_LZO_16K 5
> +#define BTRFS_ENCODED_IO_COMPRESSION_LZO_32K 6
> +#define BTRFS_ENCODED_IO_COMPRESSION_LZO_64K 7
> +#define BTRFS_ENCODED_IO_COMPRESSION_TYPES 8
> +
> +/* Data is not encrypted. */
> +#define BTRFS_ENCODED_IO_ENCRYPTION_NONE 0
> +#define BTRFS_ENCODED_IO_ENCRYPTION_TYPES 1

How about an enums for encryption/compression.


> +
>  /* Error codes as returned by the kernel */
>  enum btrfs_err_code {
>  	BTRFS_ERROR_DEV_RAID1_MIN_NOT_MET = 1,
> @@ -989,5 +1117,9 @@ enum btrfs_err_code {
>  				struct btrfs_ioctl_ino_lookup_user_args)
>  #define BTRFS_IOC_SNAP_DESTROY_V2 _IOW(BTRFS_IOCTL_MAGIC, 63, \
>  				struct btrfs_ioctl_vol_args_v2)
> +#define BTRFS_IOC_ENCODED_READ _IOR(BTRFS_IOCTL_MAGIC, 64, \
> +				    struct btrfs_ioctl_encoded_io_args)
> +#define BTRFS_IOC_ENCODED_WRITE _IOW(BTRFS_IOCTL_MAGIC, 64, \
> +				     struct btrfs_ioctl_encoded_io_args)
>  
>  #endif /* _UAPI_LINUX_BTRFS_H */
> 

Re: [PATCH v10 06/14] btrfs: optionally extend i_size in cow_file_range_inline()

[Qu Wenruo]

On 2021/8/20 下午4:51, Nikolay Borisov wrote:
>
>
> On 18.08.21 г. 0:06, Omar Sandoval wrote:
>> From: Omar Sandoval <osandov@fb.com>
>>
>> Currently, an inline extent is always created after i_size is extended
>> from btrfs_dirty_pages(). However, for encoded writes, we only want to
>> update i_size after we successfully created the inline extent.

To me, the idea of write first then update isize is just going to cause
tons of inline extent related prblems.

The current example is falloc, which only update the isize after the
falloc finishes.

This behavior has already bothered me quite a lot, as it can easily
create mixed inline and regular extents.

Can't we remember the old isize (with proper locking), enlarge isize
(with holes filled), do the write.

If something wrong happened, we truncate the isize back to its old isize.

>> Add an
>> update_i_size parameter to cow_file_range_inline() and
>> insert_inline_extent() and pass in the size of the extent rather than
>> determining it from i_size. Since the start parameter is always passed
>> as 0, get rid of it and simplify the logic in these two functions. While
>> we're here, let's document the requirements for creating an inline
>> extent.
>>
>> Reviewed-by: Josef Bacik <josef@toxicpanda.com>
>> Signed-off-by: Omar Sandoval <osandov@fb.com>
>> ---
>>   fs/btrfs/inode.c | 100 +++++++++++++++++++++++------------------------
>>   1 file changed, 48 insertions(+), 52 deletions(-)
>>
>> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
>> index 708d8ab098bc..0b5ff14aa7fd 100644
>> --- a/fs/btrfs/inode.c
>> +++ b/fs/btrfs/inode.c
>> @@ -236,9 +236,10 @@ static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
>>   static int insert_inline_extent(struct btrfs_trans_handle *trans,
>>   				struct btrfs_path *path, bool extent_inserted,
>>   				struct btrfs_root *root, struct inode *inode,
>> -				u64 start, size_t size, size_t compressed_size,
>> +				size_t size, size_t compressed_size,
>>   				int compress_type,
>> -				struct page **compressed_pages)
>> +				struct page **compressed_pages,
>> +				bool update_i_size)
>>   {
>>   	struct extent_buffer *leaf;
>>   	struct page *page = NULL;
>> @@ -247,7 +248,7 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
>>   	struct btrfs_file_extent_item *ei;
>>   	int ret;
>>   	size_t cur_size = size;
>> -	unsigned long offset;
>> +	u64 i_size;
>>
>>   	ASSERT((compressed_size > 0 && compressed_pages) ||
>>   	       (compressed_size == 0 && !compressed_pages));
>> @@ -260,7 +261,7 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
>>   		size_t datasize;
>>
>>   		key.objectid = btrfs_ino(BTRFS_I(inode));
>> -		key.offset = start;
>> +		key.offset = 0;
>>   		key.type = BTRFS_EXTENT_DATA_KEY;
>>
>>   		datasize = btrfs_file_extent_calc_inline_size(cur_size);
>> @@ -297,12 +298,10 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
>>   		btrfs_set_file_extent_compression(leaf, ei,
>>   						  compress_type);
>>   	} else {
>> -		page = find_get_page(inode->i_mapping,
>> -				     start >> PAGE_SHIFT);
>> +		page = find_get_page(inode->i_mapping, 0);
>>   		btrfs_set_file_extent_compression(leaf, ei, 0);
>>   		kaddr = kmap_atomic(page);
>> -		offset = offset_in_page(start);
>> -		write_extent_buffer(leaf, kaddr + offset, ptr, size);
>> +		write_extent_buffer(leaf, kaddr, ptr, size);
>>   		kunmap_atomic(kaddr);
>>   		put_page(page);
>>   	}
>> @@ -313,8 +312,8 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
>>   	 * We align size to sectorsize for inline extents just for simplicity
>>   	 * sake.
>>   	 */
>> -	size = ALIGN(size, root->fs_info->sectorsize);
>> -	ret = btrfs_inode_set_file_extent_range(BTRFS_I(inode), start, size);
>> +	ret = btrfs_inode_set_file_extent_range(BTRFS_I(inode), 0,
>> +					ALIGN(size, root->fs_info->sectorsize));
>>   	if (ret)
>>   		goto fail;
>>
>> @@ -327,7 +326,13 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
>>   	 * before we unlock the pages.  Otherwise we
>>   	 * could end up racing with unlink.
>>   	 */
>> -	BTRFS_I(inode)->disk_i_size = inode->i_size;
>> +	i_size = i_size_read(inode);
>> +	if (update_i_size && size > i_size) {
>> +		i_size_write(inode, size);
>> +		i_size = size;
>> +	}
>> +	BTRFS_I(inode)->disk_i_size = i_size;
>> +
>>   fail:
>>   	return ret;
>>   }
>> @@ -338,35 +343,31 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
>>    * does the checks required to make sure the data is small enough
>>    * to fit as an inline extent.
>>    */
>> -static noinline int cow_file_range_inline(struct btrfs_inode *inode, u64 start,
>> -					  u64 end, size_t compressed_size,
>> +static noinline int cow_file_range_inline(struct btrfs_inode *inode, u64 size,
>> +					  size_t compressed_size,
>>   					  int compress_type,
>> -					  struct page **compressed_pages)
>> +					  struct page **compressed_pages,
>> +					  bool update_i_size)
>>   {
>>   	struct btrfs_drop_extents_args drop_args = { 0 };
>>   	struct btrfs_root *root = inode->root;
>>   	struct btrfs_fs_info *fs_info = root->fs_info;
>>   	struct btrfs_trans_handle *trans;
>> -	u64 isize = i_size_read(&inode->vfs_inode);
>> -	u64 actual_end = min(end + 1, isize);
>> -	u64 inline_len = actual_end - start;
>> -	u64 aligned_end = ALIGN(end, fs_info->sectorsize);
>> -	u64 data_len = inline_len;
>> +	u64 data_len = compressed_size ? compressed_size : size;
>>   	int ret;
>>   	struct btrfs_path *path;
>>
>> -	if (compressed_size)
>> -		data_len = compressed_size;
>> -
>> -	if (start > 0 ||
>> -	    actual_end > fs_info->sectorsize ||
>> +	/*
>> +	 * We can create an inline extent if it ends at or beyond the current
>> +	 * i_size, is no larger than a sector (decompressed), and the (possibly
>> +	 * compressed) data fits in a leaf and the configured maximum inline
>> +	 * size.
>> +	 */
>
> Urgh, just some days ago Qu was talking about how awkward it is to have
> mixed extents in a file. And now, AFAIU, you are making them more likely
> since now they can be created not just at the beginning of the file but
> also after i_size write. While this won't be a problem in and of itself
> it goes just the opposite way of us trying to shrink the possible cases
> when we can have mixed extents.

Tree-checker should reject such inline extent at non-zero offset.

> Qu what is your take on that?

My question is, why encoded write needs to bother the inline extents at all?

My intuition of such encoded write is, it should not create inline
extents at all.

Or is there any special use-case involved for encoded write?

Thanks,
Qu


>
> <snip>
>

Re: [PATCH v10 08/14] btrfs: add BTRFS_IOC_ENCODED_READ

[Nikolay Borisov]

On 18.08.21 г. 0:06, Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
> 
> There are 4 main cases:
> 
> 1. Inline extents: we copy the data straight out of the extent buffer.
> 2. Hole/preallocated extents: we fill in zeroes.
> 3. Regular, uncompressed extents: we read the sectors we need directly
>    from disk.
> 4. Regular, compressed extents: we read the entire compressed extent
>    from disk and indicate what subset of the decompressed extent is in
>    the file.
> 
> This initial implementation simplifies a few things that can be improved
> in the future:
> 
> - We hold the inode lock during the operation.
> - Cases 1, 3, and 4 allocate temporary memory to read into before
>   copying out to userspace.
> - We don't do read repair, because it turns out that read repair is
>   currently broken for compressed data.
> 
> Signed-off-by: Omar Sandoval <osandov@fb.com>
> ---
>  fs/btrfs/ctree.h |   4 +
>  fs/btrfs/inode.c | 489 +++++++++++++++++++++++++++++++++++++++++++++++
>  fs/btrfs/ioctl.c | 111 +++++++++++
>  3 files changed, 604 insertions(+)
> 
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index 973616d80080..b68d8ea42f6e 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -3219,6 +3219,10 @@ int btrfs_writepage_cow_fixup(struct page *page);
>  void btrfs_writepage_endio_finish_ordered(struct btrfs_inode *inode,
>  					  struct page *page, u64 start,
>  					  u64 end, bool uptodate);
> +struct btrfs_ioctl_encoded_io_args;
> +ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter,
> +			   struct btrfs_ioctl_encoded_io_args *encoded);
> +
>  extern const struct dentry_operations btrfs_dentry_operations;
>  extern const struct iomap_ops btrfs_dio_iomap_ops;
>  extern const struct iomap_dio_ops btrfs_dio_ops;
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 0b5ff14aa7fd..6d7fae859fb5 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -10496,6 +10496,495 @@ void btrfs_set_range_writeback(struct btrfs_inode *inode, u64 start, u64 end)
>  	}
>  }
>  
> +static int btrfs_encoded_io_compression_from_extent(int compress_type)
> +{
> +	switch (compress_type) {
> +	case BTRFS_COMPRESS_NONE:
> +		return BTRFS_ENCODED_IO_COMPRESSION_NONE;
> +	case BTRFS_COMPRESS_ZLIB:
> +		return BTRFS_ENCODED_IO_COMPRESSION_ZLIB;
> +	case BTRFS_COMPRESS_LZO:
> +		/*
> +		 * The LZO format depends on the page size. 64k is the maximum
> +		 * sectorsize (and thus page size) that we support.
> +		 */
> +		if (PAGE_SIZE < SZ_4K || PAGE_SIZE > SZ_64K)
> +			return -EINVAL;
> +		return BTRFS_ENCODED_IO_COMPRESSION_LZO_4K + (PAGE_SHIFT - 12);
> +	case BTRFS_COMPRESS_ZSTD:
> +		return BTRFS_ENCODED_IO_COMPRESSION_ZSTD;
> +	default:
> +		return -EUCLEAN;
> +	}
> +}
> +
> +static ssize_t btrfs_encoded_read_inline(
> +				struct kiocb *iocb,
> +				struct iov_iter *iter, u64 start,
> +				u64 lockend,
> +				struct extent_state **cached_state,
> +				u64 extent_start, size_t count,
> +				struct btrfs_ioctl_encoded_io_args *encoded,
> +				bool *unlocked)
> +{
> +	struct inode *inode = file_inode(iocb->ki_filp);
> +	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
> +	struct btrfs_path *path;
> +	struct extent_buffer *leaf;
> +	struct btrfs_file_extent_item *item;
> +	u64 ram_bytes;
> +	unsigned long ptr;
> +	void *tmp;
> +	ssize_t ret;
> +
> +	path = btrfs_alloc_path();
> +	if (!path) {
> +		ret = -ENOMEM;
> +		goto out;
> +	}
> +	ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root, path,
> +				       btrfs_ino(BTRFS_I(inode)), extent_start,
> +				       0);
> +	if (ret) {
> +		if (ret > 0) {
> +			/* The extent item disappeared? */
> +			ret = -EIO;
> +		}
> +		goto out;
> +	}
> +	leaf = path->nodes[0];
> +	item = btrfs_item_ptr(leaf, path->slots[0],
> +			      struct btrfs_file_extent_item);
> +
> +	ram_bytes = btrfs_file_extent_ram_bytes(leaf, item);
> +	ptr = btrfs_file_extent_inline_start(item);
> +
> +	encoded->len = (min_t(u64, extent_start + ram_bytes, inode->i_size) -
> +			iocb->ki_pos);
> +	ret = btrfs_encoded_io_compression_from_extent(
> +				 btrfs_file_extent_compression(leaf, item));
> +	if (ret < 0)
> +		goto out;
> +	encoded->compression = ret;
> +	if (encoded->compression) {
> +		size_t inline_size;
> +
> +		inline_size = btrfs_file_extent_inline_item_len(leaf,
> +						btrfs_item_nr(path->slots[0]));
> +		if (inline_size > count) {
> +			ret = -ENOBUFS;
> +			goto out;
> +		}
> +		count = inline_size;
> +		encoded->unencoded_len = ram_bytes;
> +		encoded->unencoded_offset = iocb->ki_pos - extent_start;
> +	} else {
> +		encoded->len = encoded->unencoded_len = count =
> +			min_t(u64, count, encoded->len);
> +		ptr += iocb->ki_pos - extent_start;
> +	}
> +
> +	tmp = kmalloc(count, GFP_NOFS);
> +	if (!tmp) {
> +		ret = -ENOMEM;
> +		goto out;
> +	}
> +	read_extent_buffer(leaf, tmp, ptr, count);
> +	btrfs_release_path(path);
> +	unlock_extent_cached(io_tree, start, lockend, cached_state);
> +	inode_unlock_shared(inode);
> +	*unlocked = true;
> +
> +	ret = copy_to_iter(tmp, count, iter);
> +	if (ret != count)
> +		ret = -EFAULT;
> +	kfree(tmp);
> +out:
> +	btrfs_free_path(path);
> +	return ret;
> +}
> +
> +struct btrfs_encoded_read_private {
> +	struct inode *inode;
> +	wait_queue_head_t wait;
> +	atomic_t pending;
> +	blk_status_t status;
> +	bool skip_csum;
> +};
> +
> +static blk_status_t submit_encoded_read_bio(struct inode *inode,
> +					    struct bio *bio, int mirror_num,
> +					    unsigned long bio_flags)
> +{
> +	struct btrfs_encoded_read_private *priv = bio->bi_private;
> +	struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
> +	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> +	blk_status_t ret;
> +
> +	if (!priv->skip_csum) {
> +		ret = btrfs_lookup_bio_sums(inode, bio, NULL);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DATA);
> +	if (ret) {
> +		btrfs_io_bio_free_csum(io_bio);
> +		return ret;
> +	}
> +
> +	atomic_inc(&priv->pending);
> +	ret = btrfs_map_bio(fs_info, bio, mirror_num);
> +	if (ret) {
> +		atomic_dec(&priv->pending);
> +		btrfs_io_bio_free_csum(io_bio);
> +	}
> +	return ret;
> +}
> +
> +static blk_status_t btrfs_encoded_read_check_bio(struct btrfs_io_bio *io_bio)
> +{
> +	const bool uptodate = io_bio->bio.bi_status == BLK_STS_OK;
> +	struct btrfs_encoded_read_private *priv = io_bio->bio.bi_private;
> +	struct inode *inode = priv->inode;
> +	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> +	u32 sectorsize = fs_info->sectorsize;
> +	struct bio_vec *bvec;
> +	struct bvec_iter_all iter_all;
> +	u64 start = io_bio->logical;
> +	u32 bio_offset = 0;
> +
> +	if (priv->skip_csum || !uptodate)
> +		return io_bio->bio.bi_status;
> +
> +	bio_for_each_segment_all(bvec, &io_bio->bio, iter_all) {
> +		unsigned int i, nr_sectors, pgoff;
> +
> +		nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);
> +		pgoff = bvec->bv_offset;
> +		for (i = 0; i < nr_sectors; i++) {
> +			ASSERT(pgoff < PAGE_SIZE);
> +			if (check_data_csum(inode, io_bio, bio_offset,
> +					    bvec->bv_page, pgoff, start))
> +				return BLK_STS_IOERR;
> +			start += sectorsize;
> +			bio_offset += sectorsize;
> +			pgoff += sectorsize;
> +		}
> +	}
> +	return BLK_STS_OK;
> +}
> +
> +static void btrfs_encoded_read_endio(struct bio *bio)
> +{
> +	struct btrfs_encoded_read_private *priv = bio->bi_private;
> +	struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
> +	blk_status_t status;
> +
> +	status = btrfs_encoded_read_check_bio(io_bio);
> +	if (status) {
> +		/*
> +		 * The memory barrier implied by the atomic_dec_return() here
> +		 * pairs with the memory barrier implied by the
> +		 * atomic_dec_return() or io_wait_event() in
> +		 * btrfs_encoded_read_regular_fill_pages() to ensure that this
> +		 * write is observed before the load of status in
> +		 * btrfs_encoded_read_regular_fill_pages().
> +		 */
> +		WRITE_ONCE(priv->status, status);
> +	}
> +	if (!atomic_dec_return(&priv->pending))
> +		wake_up(&priv->wait);
> +	btrfs_io_bio_free_csum(io_bio);
> +	bio_put(bio);
> +}
> +
> +static int btrfs_encoded_read_regular_fill_pages(struct inode *inode, u64 offset,
> +						 u64 disk_io_size, struct page **pages)
> +{
> +	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> +	struct btrfs_encoded_read_private priv = {
> +		.inode = inode,
> +		.pending = ATOMIC_INIT(1),
> +		.skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM,
> +	};
> +	unsigned long i = 0;
> +	u64 cur = 0;
> +	int ret;
> +
> +	init_waitqueue_head(&priv.wait);
> +	/*
> +	 * Submit bios for the extent, splitting due to bio or stripe limits as
> +	 * necessary.
> +	 */
> +	while (cur < disk_io_size) {
> +		struct extent_map *em;
> +		struct btrfs_io_geometry geom;
> +		struct bio *bio = NULL;
> +		u64 remaining;
> +
> +		em = btrfs_get_chunk_map(fs_info, offset + cur,
> +					 disk_io_size - cur);
> +		if (IS_ERR(em)) {
> +			ret = PTR_ERR(em);
> +		} else {
> +			ret = btrfs_get_io_geometry(fs_info, em, BTRFS_MAP_READ,
> +						    offset + cur, &geom);
> +			free_extent_map(em);
> +		}
> +		if (ret) {
> +			WRITE_ONCE(priv.status, errno_to_blk_status(ret));
> +			break;
> +		}
> +		remaining = min(geom.len, disk_io_size - cur);
> +		while (bio || remaining) {
> +			size_t bytes = min_t(u64, remaining, PAGE_SIZE);
> +
> +			if (!bio) {
> +				bio = btrfs_bio_alloc(offset + cur);
> +				bio->bi_end_io = btrfs_encoded_read_endio;
> +				bio->bi_private = &priv;
> +				bio->bi_opf = REQ_OP_READ;
> +			}
> +
> +			if (!bytes ||
> +			    bio_add_page(bio, pages[i], bytes, 0) < bytes) {
> +				blk_status_t status;
> +
> +				status = submit_encoded_read_bio(inode, bio, 0,
> +								 0);
> +				if (status) {
> +					WRITE_ONCE(priv.status, status);
> +					bio_put(bio);
> +					goto out;
> +				}
> +				bio = NULL;
> +				continue;
> +			}
> +
> +			i++;
> +			cur += bytes;
> +			remaining -= bytes;
> +		}
> +	}
> +
> +out:
> +	if (atomic_dec_return(&priv.pending))
> +		io_wait_event(priv.wait, !atomic_read(&priv.pending));
> +	/* See btrfs_encoded_read_endio() for ordering. */
> +	return blk_status_to_errno(READ_ONCE(priv.status));
> +}
> +
> +static ssize_t btrfs_encoded_read_regular(struct kiocb *iocb,
> +					  struct iov_iter *iter,
> +					  u64 start, u64 lockend,
> +					  struct extent_state **cached_state,
> +					  u64 offset, u64 disk_io_size,
> +					  size_t count, bool compressed,
> +					  bool *unlocked)
> +{
> +	struct inode *inode = file_inode(iocb->ki_filp);
> +	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
> +	struct page **pages;
> +	unsigned long nr_pages, i;
> +	u64 cur;
> +	size_t page_offset;
> +	ssize_t ret;
> +
> +	nr_pages = DIV_ROUND_UP(disk_io_size, PAGE_SIZE);
> +	pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
> +	if (!pages)
> +		return -ENOMEM;
> +	for (i = 0; i < nr_pages; i++) {
> +		pages[i] = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
> +		if (!pages[i]) {
> +			ret = -ENOMEM;
> +			goto out;
> +		}
> +	}
> +
> +	ret = btrfs_encoded_read_regular_fill_pages(inode, offset, disk_io_size,
> +						    pages);
> +	if (ret)
> +		goto out;
> +
> +	unlock_extent_cached(io_tree, start, lockend, cached_state);
> +	inode_unlock_shared(inode);
> +	*unlocked = true;
> +
> +	if (compressed) {
> +		i = 0;
> +		page_offset = 0;
> +	} else {
> +		i = (iocb->ki_pos - start) >> PAGE_SHIFT;
> +		page_offset = (iocb->ki_pos - start) & (PAGE_SIZE - 1);
> +	}
> +	cur = 0;
> +	while (cur < count) {
> +		size_t bytes = min_t(size_t, count - cur,
> +				     PAGE_SIZE - page_offset);
> +
> +		if (copy_page_to_iter(pages[i], page_offset, bytes,
> +				      iter) != bytes) {
> +			ret = -EFAULT;
> +			goto out;
> +		}
> +		i++;
> +		cur += bytes;
> +		page_offset = 0;
> +	}
> +	ret = count;
> +out:
> +	for (i = 0; i < nr_pages; i++) {
> +		if (pages[i])
> +			__free_page(pages[i]);
> +	}
> +	kfree(pages);
> +	return ret;
> +}
> +
> +ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter,
> +			   struct btrfs_ioctl_encoded_io_args *encoded)
> +{
> +	struct inode *inode = file_inode(iocb->ki_filp);
> +	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> +	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
> +	ssize_t ret;
> +	size_t count = iov_iter_count(iter);
> +	u64 start, lockend, offset, disk_io_size;
> +	struct extent_state *cached_state = NULL;
> +	struct extent_map *em;
> +	bool unlocked = false;
> +
> +	file_accessed(iocb->ki_filp);
> +
> +	inode_lock_shared(inode);
> +
> +	if (iocb->ki_pos >= inode->i_size) {
> +		inode_unlock_shared(inode);
> +		return 0;

Don't we need to signal beyond EOF reads somehow. As it stands returning
0 means returning zeroed portion of btrfs_ioctl_encoded_io_args to user
space?

> +	}
> +	start = ALIGN_DOWN(iocb->ki_pos, fs_info->sectorsize);
> +	/*
> +	 * We don't know how long the extent containing iocb->ki_pos is, but if
> +	 * it's compressed we know that it won't be longer than this.
> +	 */
> +	lockend = start + BTRFS_MAX_UNCOMPRESSED - 1;
> +
> +	for (;;) {
> +		struct btrfs_ordered_extent *ordered;
> +
> +		ret = btrfs_wait_ordered_range(inode, start,
> +					       lockend - start + 1);
> +		if (ret)
> +			goto out_unlock_inode;
> +		lock_extent_bits(io_tree, start, lockend, &cached_state);
> +		ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
> +						     lockend - start + 1);
> +		if (!ordered)
> +			break;
> +		btrfs_put_ordered_extent(ordered);
> +		unlock_extent_cached(io_tree, start, lockend, &cached_state);
> +		cond_resched();
> +	}
Can't you simply use btrfs_lock_and_flush_ordered_range, the major
difference is btrfs_wait_ordered_range basically instantiates any
pending delalloc, whilst btrfs_lock_and_flush_ordered_range returns with
any, already-instantiated OE run to completion and the range locked ?

> +
> +	em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start,
> +			      lockend - start + 1);
> +	if (IS_ERR(em)) {
> +		ret = PTR_ERR(em);
> +		goto out_unlock_extent;
> +	}
> +
> +	if (em->block_start == EXTENT_MAP_INLINE) {
> +		u64 extent_start = em->start;
> +
> +		/*
> +		 * For inline extents we get everything we need out of the
> +		 * extent item.
> +		 */
> +		free_extent_map(em);
> +		em = NULL;
> +		ret = btrfs_encoded_read_inline(iocb, iter, start, lockend,
> +						&cached_state, extent_start,
> +						count, encoded, &unlocked);
> +		goto out;
> +	}
> +
> +	/*
> +	 * We only want to return up to EOF even if the extent extends beyond
> +	 * that.
> +	 */
> +	encoded->len = (min_t(u64, extent_map_end(em), inode->i_size) -
> +			iocb->ki_pos);
> +	if (em->block_start == EXTENT_MAP_HOLE ||
> +	    test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
> +		offset = EXTENT_MAP_HOLE;
> +		encoded->len = encoded->unencoded_len = count =
> +			min_t(u64, count, encoded->len);
> +	} else if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
> +		offset = em->block_start;
> +		/*
> +		 * Bail if the buffer isn't large enough to return the whole
> +		 * compressed extent.
> +		 */
> +		if (em->block_len > count) {
> +			ret = -ENOBUFS;
> +			goto out_em;
> +		}
> +		disk_io_size = count = em->block_len;
> +		encoded->unencoded_len = em->ram_bytes;
> +		encoded->unencoded_offset = iocb->ki_pos - em->orig_start;
> +		ret = btrfs_encoded_io_compression_from_extent(
> +							     em->compress_type);
> +		if (ret < 0)
> +			goto out_em;
> +		encoded->compression = ret;
> +	} else {
> +		offset = em->block_start + (start - em->start);
> +		if (encoded->len > count)
> +			encoded->len = count;
> +		/*
> +		 * Don't read beyond what we locked. This also limits the page
> +		 * allocations that we'll do.
> +		 */
> +		disk_io_size = min(lockend + 1,
> +				   iocb->ki_pos + encoded->len) - start;
> +		encoded->len = encoded->unencoded_len = count =
> +			start + disk_io_size - iocb->ki_pos;
> +		disk_io_size = ALIGN(disk_io_size, fs_info->sectorsize);
> +	}
> +	free_extent_map(em);
> +	em = NULL;
> +
> +	if (offset == EXTENT_MAP_HOLE) {
> +		unlock_extent_cached(io_tree, start, lockend, &cached_state);
> +		inode_unlock_shared(inode);
> +		unlocked = true;
> +		ret = iov_iter_zero(count, iter);
> +		if (ret != count)
> +			ret = -EFAULT;
> +	} else {
> +		ret = btrfs_encoded_read_regular(iocb, iter, start, lockend,
> +						 &cached_state, offset,
> +						 disk_io_size, count,
> +						 encoded->compression,
> +						 &unlocked);
> +	}
> +
> +out:
> +	if (ret >= 0)
> +		iocb->ki_pos += encoded->len;
> +out_em:
> +	free_extent_map(em);
> +out_unlock_extent:
> +	if (!unlocked)
> +		unlock_extent_cached(io_tree, start, lockend, &cached_state);
> +out_unlock_inode:
> +	if (!unlocked)
> +		inode_unlock_shared(inode);
> +	return ret;
> +}
> +
>  #ifdef CONFIG_SWAP
>  /*
>   * Add an entry indicating a block group or device which is pinned by a

<snip>

>  /* Mask out flags that are inappropriate for the given type of inode. */
> @@ -4887,6 +4904,94 @@ static int _btrfs_ioctl_send(struct file *file, void __user *argp, bool compat)
>  	return ret;
>  }
>  
> +static int btrfs_ioctl_encoded_read(struct file *file, void __user *argp,
> +				    bool compat)
> +{
> +	struct btrfs_ioctl_encoded_io_args args;

nit: If you make this args = {}; you guarantee it's zeroed out then you
can get rid of the ugly memset further down.

> +	size_t copy_end_kernel = offsetofend(struct btrfs_ioctl_encoded_io_args,
> +					     flags);
> +	size_t copy_end;
> +	struct iovec iovstack[UIO_FASTIOV];
> +	struct iovec *iov = iovstack;
> +	struct iov_iter iter;
> +	loff_t pos;
> +	struct kiocb kiocb;
> +	ssize_t ret;
> +
> +	if (!capable(CAP_SYS_ADMIN)) {
> +		ret = -EPERM;
> +		goto out_acct;
> +	}
> +
> +	if (compat) {
> +#if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
> +		struct btrfs_ioctl_encoded_io_args_32 args32;
> +
> +		copy_end = offsetofend(struct btrfs_ioctl_encoded_io_args_32,
> +				       flags);
> +		if (copy_from_user(&args32, argp, copy_end)) {
> +			ret = -EFAULT;
> +			goto out_acct;
> +		}
> +		args.iov = compat_ptr(args32.iov);
> +		args.iovcnt = args32.iovcnt;
> +		args.offset = args32.offset;
> +		args.flags = args32.flags;
> +#else
> +		return -ENOTTY;
> +#endif
> +	} else {
> +		copy_end = copy_end_kernel;
> +		if (copy_from_user(&args, argp, copy_end)) {
> +			ret = -EFAULT;
> +			goto out_acct;
> +		}
> +	}
> +	if (args.flags != 0) {
> +		ret = -EINVAL;
> +		goto out_acct;
> +	}
> +	memset((char *)&args + copy_end_kernel, 0,
> +	       sizeof(args) - copy_end_kernel);
> +
> +	ret = import_iovec(READ, args.iov, args.iovcnt, ARRAY_SIZE(iovstack),
> +			   &iov, &iter);
> +	if (ret < 0)
> +		goto out_acct;
> +
> +	if (iov_iter_count(&iter) == 0) {
> +		ret = 0;
> +		goto out_iov;
> +	}
> +	pos = args.offset;
> +	ret = rw_verify_area(READ, file, &pos, args.len);
> +	if (ret < 0)
> +		goto out_iov;
> +
> +	init_sync_kiocb(&kiocb, file);
> +	ret = kiocb_set_rw_flags(&kiocb, 0);
> +	if (ret)
> +		goto out_iov;
> +	kiocb.ki_pos = pos;
> +
> +	ret = btrfs_encoded_read(&kiocb, &iter, &args);
> +	if (ret >= 0) {
> +		fsnotify_access(file);
> +		if (copy_to_user(argp + copy_end,
> +				 (char *)&args + copy_end_kernel,
> +				 sizeof(args) - copy_end_kernel))
> +			ret = -EFAULT;
> +	}
> +
> +out_iov:
> +	kfree(iov);
> +out_acct:
> +	if (ret > 0)
> +		add_rchar(current, ret);
> +	inc_syscr(current);
> +	return ret;
> +}
> +
>  long btrfs_ioctl(struct file *file, unsigned int
>  		cmd, unsigned long arg)
>  {

Re: [PATCH v10 09/14] btrfs: add BTRFS_IOC_ENCODED_WRITE

[Nikolay Borisov]

On 18.08.21 г. 0:06, Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
> 
> The implementation resembles direct I/O: we have to flush any ordered
> extents, invalidate the page cache, and do the io tree/delalloc/extent
> map/ordered extent dance. From there, we can reuse the compression code
> with a minor modification to distinguish the write from writeback. This
> also creates inline extents when possible.
> 
> Signed-off-by: Omar Sandoval <osandov@fb.com>

<snip>

>   * Add an entry indicating a block group or device which is pinned by a
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 7a0a9c752624..13a0a65c6a43 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -103,6 +103,8 @@ struct btrfs_ioctl_encoded_io_args_32 {
>  
>  #define BTRFS_IOC_ENCODED_READ_32 _IOR(BTRFS_IOCTL_MAGIC, 64, \
>  				       struct btrfs_ioctl_encoded_io_args_32)
> +#define BTRFS_IOC_ENCODED_WRITE_32 _IOW(BTRFS_IOCTL_MAGIC, 64, \
> +					struct btrfs_ioctl_encoded_io_args_32)
>  #endif
>  
>  /* Mask out flags that are inappropriate for the given type of inode. */
> @@ -4992,6 +4994,102 @@ static int btrfs_ioctl_encoded_read(struct file *file, void __user *argp,
>  	return ret;
>  }
>  
> +static int btrfs_ioctl_encoded_write(struct file *file, void __user *argp,
> +				     bool compat)
> +{
> +	struct btrfs_ioctl_encoded_io_args args;
> +	struct iovec iovstack[UIO_FASTIOV];
> +	struct iovec *iov = iovstack;
> +	struct iov_iter iter;
> +	loff_t pos;
> +	struct kiocb kiocb;
> +	ssize_t ret;
> +
> +	if (!capable(CAP_SYS_ADMIN)) {
> +		ret = -EPERM;
> +		goto out_acct;
> +	}
> +
> +	if (!(file->f_mode & FMODE_WRITE)) {
> +		ret = -EBADF;
> +		goto out_acct;
> +	}
> +
> +	if (compat) {
> +#if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
> +		struct btrfs_ioctl_encoded_io_args_32 args32;
> +
> +		if (copy_from_user(&args32, argp, sizeof(args32))) {
> +			ret = -EFAULT;
> +			goto out_acct;
> +		}
> +		args.iov = compat_ptr(args32.iov);
> +		args.iovcnt = args.iovcnt;
> +		memcpy(&args.offset, &args32.offset,
> +		       sizeof(args) -
> +		       offsetof(struct btrfs_ioctl_encoded_io_args, offset));
> +#else
> +		return -ENOTTY;
> +#endif
> +	} else {
> +		if (copy_from_user(&args, argp, sizeof(args))) {
> +			ret = -EFAULT;
> +			goto out_acct;
> +		}
> +	}
> +
> +	ret = -EINVAL;
> +	if (args.flags != 0)
> +		goto out_acct;
> +	if (memchr_inv(args.reserved, 0, sizeof(args.reserved)))
> +		goto out_acct;
> +	if (args.compression == BTRFS_ENCODED_IO_COMPRESSION_NONE &&
> +	    args.encryption == BTRFS_ENCODED_IO_ENCRYPTION_NONE)

Do you intend on supporting encrypted data writeout in the future, given
that in btrfs_do_encoded_write EINVAL is returned if the data to be
written is encrypted? If not then this check could be moved earlier to
fail fast.

<snip>

> @@ -5138,9 +5236,13 @@ long btrfs_ioctl(struct file *file, unsigned int
>  		return fsverity_ioctl_measure(file, argp);
>  	case BTRFS_IOC_ENCODED_READ:
>  		return btrfs_ioctl_encoded_read(file, argp, false);
> +	case BTRFS_IOC_ENCODED_WRITE:
> +		return btrfs_ioctl_encoded_write(file, argp, false);
>  #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
>  	case BTRFS_IOC_ENCODED_READ_32:
>  		return btrfs_ioctl_encoded_read(file, argp, true);
> +	case BTRFS_IOC_ENCODED_WRITE_32:
> +		return btrfs_ioctl_encoded_write(file, argp, true);
>  #endif
>  	}
>  
> diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
> index 550c34fa0e6d..180f302dee93 100644
> --- a/fs/btrfs/ordered-data.c
> +++ b/fs/btrfs/ordered-data.c
> @@ -521,9 +521,15 @@ void btrfs_remove_ordered_extent(struct btrfs_inode *btrfs_inode,
>  	spin_lock(&btrfs_inode->lock);
>  	btrfs_mod_outstanding_extents(btrfs_inode, -1);
>  	spin_unlock(&btrfs_inode->lock);
> -	if (root != fs_info->tree_root)
> -		btrfs_delalloc_release_metadata(btrfs_inode, entry->num_bytes,
> -						false);
> +	if (root != fs_info->tree_root) {
> +		u64 release;
> +
> +		if (test_bit(BTRFS_ORDERED_ENCODED, &entry->flags))
> +			release = entry->disk_num_bytes;
> +		else
> +			release = entry->num_bytes;
> +		btrfs_delalloc_release_metadata(btrfs_inode, release, false);
> +	}
>  
>  	percpu_counter_add_batch(&fs_info->ordered_bytes, -entry->num_bytes,
>  				 fs_info->delalloc_batch);
> diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
> index 0feb0c29839e..04588ccad34c 100644
> --- a/fs/btrfs/ordered-data.h
> +++ b/fs/btrfs/ordered-data.h
> @@ -74,6 +74,8 @@ enum {
>  	BTRFS_ORDERED_LOGGED_CSUM,
>  	/* We wait for this extent to complete in the current transaction */
>  	BTRFS_ORDERED_PENDING,
> +	/* RWF_ENCODED I/O */

nit: RWF_ENCODED is no longer, we simply have ioctl-based encoded io. So
this needs to be renamed to avoid confusion for people not necessarily
faimilar with the development history of the feature.

> +	BTRFS_ORDERED_ENCODED,
>  };
>  
>  /* BTRFS_ORDERED_* flags that specify the type of the extent. */
> @@ -81,7 +83,8 @@ enum {
>  				  (1UL << BTRFS_ORDERED_NOCOW) |	\
>  				  (1UL << BTRFS_ORDERED_PREALLOC) |	\
>  				  (1UL << BTRFS_ORDERED_COMPRESSED) |	\
> -				  (1UL << BTRFS_ORDERED_DIRECT))
> +				  (1UL << BTRFS_ORDERED_DIRECT) |	\
> +				  (1UL << BTRFS_ORDERED_ENCODED))
>  
>  struct btrfs_ordered_extent {
>  	/* logical offset in the file */
> 

Re: [PATCH v10 02/14] fs: export variant of generic_write_checks without iov_iter

[Omar Sandoval]

On Fri, Aug 20, 2021 at 10:59:28AM +0300, Nikolay Borisov wrote:
> 
> 
> On 18.08.21 г. 0:06, Omar Sandoval wrote:
> > From: Omar Sandoval <osandov@fb.com>
> > 
> > Encoded I/O in Btrfs needs to check a write with a given logical size
> > without an iov_iter that matches that size (because the iov_iter we have
> > is for the compressed data). So, factor out the parts of
> > generic_write_check() that expect an iov_iter into a new
> > __generic_write_checks() function and export that.
> > 
> > Signed-off-by: Omar Sandoval <osandov@fb.com>
> > ---
> >  fs/read_write.c    | 40 ++++++++++++++++++++++------------------
> >  include/linux/fs.h |  1 +
> >  2 files changed, 23 insertions(+), 18 deletions(-)
> > 
> > diff --git a/fs/read_write.c b/fs/read_write.c
> > index 0029ff2b0ca8..3bddd5ee7f64 100644
> > --- a/fs/read_write.c
> > +++ b/fs/read_write.c
> > @@ -1633,6 +1633,26 @@ int generic_write_check_limits(struct file *file, loff_t pos, loff_t *count)
> >  	return 0;
> >  }
> >  
> > +/* Like generic_write_checks(), but takes size of write instead of iter. */
> > +int __generic_write_checks(struct kiocb *iocb, loff_t *count)
> > +{
> > +	struct file *file = iocb->ki_filp;
> > +	struct inode *inode = file->f_mapping->host;
> > +
> > +	if (IS_SWAPFILE(inode))
> > +		return -ETXTBSY;
> 
>  Missing 'if(!count) return 0' from original code ?

Good catch, thanks.

Re: [PATCH v10 03/14] btrfs: don't advance offset for compressed bios in btrfs_csum_one_bio()

[Omar Sandoval]

On Fri, Aug 20, 2021 at 11:08:41AM +0300, Nikolay Borisov wrote:
> 
> 
> On 18.08.21 г. 0:06, Omar Sandoval wrote:
> > From: Omar Sandoval <osandov@fb.com>
> > 
> > btrfs_csum_one_bio() loops over each filesystem block in the bio while
> > keeping a cursor of its current logical position in the file in order to
> > look up the ordered extent to add the checksums to. However, this
> > doesn't make much sense for compressed extents, as a sector on disk does
> > not correspond to a sector of decompressed file data. It happens to work
> > because 1) the compressed bio always covers one ordered extent and 2)
> > the size of the bio is always less than the size of the ordered extent.
> > However, the second point will not always be true for encoded writes.
> > 
> > Let's add a boolean parameter to btrfs_csum_one_bio() to indicate that
> > it can assume that the bio only covers one ordered extent. Since we're
> > already changing the signature, let's get rid of the contig parameter
> > and make it implied by the offset parameter, similar to the change we
> > recently made to btrfs_lookup_bio_sums(). Additionally, let's rename
> > nr_sectors to blockcount to make it clear that it's the number of
> > filesystem blocks, not the number of 512-byte sectors.
> > 
> > Reviewed-by: Josef Bacik <josef@toxicpanda.com>
> > Signed-off-by: Omar Sandoval <osandov@fb.com>
> > ---
> >  fs/btrfs/compression.c |  5 +++--
> >  fs/btrfs/ctree.h       |  2 +-
> >  fs/btrfs/file-item.c   | 35 ++++++++++++++++-------------------
> >  fs/btrfs/inode.c       |  8 ++++----
> >  4 files changed, 24 insertions(+), 26 deletions(-)
> > 
> > diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
> > index 7869ad12bc6e..e645b3c2f09a 100644
> > --- a/fs/btrfs/compression.c
> > +++ b/fs/btrfs/compression.c
> > @@ -480,7 +480,8 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
> >  			BUG_ON(ret); /* -ENOMEM */
> >  
> >  			if (!skip_sum) {
> > -				ret = btrfs_csum_one_bio(inode, bio, start, 1);
> > +				ret = btrfs_csum_one_bio(inode, bio, start,
> > +							 true);
> >  				BUG_ON(ret); /* -ENOMEM */
> >  			}
> >  
> > @@ -516,7 +517,7 @@ blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
> >  	BUG_ON(ret); /* -ENOMEM */
> >  
> >  	if (!skip_sum) {
> > -		ret = btrfs_csum_one_bio(inode, bio, start, 1);
> > +		ret = btrfs_csum_one_bio(inode, bio, start, true);
> >  		BUG_ON(ret); /* -ENOMEM */
> >  	}
> >  
> > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> > index f07c82fafa04..be245b4b8efe 100644
> > --- a/fs/btrfs/ctree.h
> > +++ b/fs/btrfs/ctree.h
> > @@ -3111,7 +3111,7 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
> >  			   struct btrfs_root *root,
> >  			   struct btrfs_ordered_sum *sums);
> >  blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
> > -				u64 file_start, int contig);
> > +				u64 offset, bool one_ordered);
> >  int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
> >  			     struct list_head *list, int search_commit);
> >  void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
> > diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
> > index 2673c6ba7a4e..844fae923340 100644
> > --- a/fs/btrfs/file-item.c
> > +++ b/fs/btrfs/file-item.c
> > @@ -614,28 +614,28 @@ int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
> >   * btrfs_csum_one_bio - Calculates checksums of the data contained inside a bio
> >   * @inode:	 Owner of the data inside the bio
> >   * @bio:	 Contains the data to be checksummed
> > - * @file_start:  offset in file this bio begins to describe
> > - * @contig:	 Boolean. If true/1 means all bio vecs in this bio are
> > - *		 contiguous and they begin at @file_start in the file. False/0
> > - *		 means this bio can contain potentially discontiguous bio vecs
> > - *		 so the logical offset of each should be calculated separately.
> > + * @offset:      If (u64)-1, @bio may contain discontiguous bio vecs, so the
> > + *               file offsets are determined from the page offsets in the bio.
> > + *               Otherwise, this is the starting file offset of the bio vecs in
> > + *               @bio, which must be contiguous.
> > + * @one_ordered: If true, @bio only refers to one ordered extent.
> 
> nit: I don't have strong preference but my gut feeling tells me
> "single_ordered" might be more explicit/informative. But unless someone
> else thinks the same one_ordered would also make do
> 
> >   */
> >  blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
> > -		       u64 file_start, int contig)
> > +				u64 offset, bool one_ordered)
> >  {
> >  	struct btrfs_fs_info *fs_info = inode->root->fs_info;
> >  	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
> >  	struct btrfs_ordered_sum *sums;
> >  	struct btrfs_ordered_extent *ordered = NULL;
> > +	const bool page_offsets = (offset == (u64)-1);
> 
> nit: Again, instead of page_offsets perhaps use_page_offsets, somewhat
> more explicit/informative.

Sure, that sounds better.

> >  	char *data;
> >  	struct bvec_iter iter;
> >  	struct bio_vec bvec;
> >  	int index;
> > -	int nr_sectors;
> > +	int blockcount;
> >  	unsigned long total_bytes = 0;
> >  	unsigned long this_sum_bytes = 0;
> >  	int i;
> > -	u64 offset;
> >  	unsigned nofs_flag;
> >  
> >  	nofs_flag = memalloc_nofs_save();
> > @@ -649,18 +649,13 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
> >  	sums->len = bio->bi_iter.bi_size;
> >  	INIT_LIST_HEAD(&sums->list);
> >  
> > -	if (contig)
> > -		offset = file_start;
> > -	else
> > -		offset = 0; /* shut up gcc */
> > -
> >  	sums->bytenr = bio->bi_iter.bi_sector << 9;
> >  	index = 0;
> >  
> >  	shash->tfm = fs_info->csum_shash;
> >  
> >  	bio_for_each_segment(bvec, bio, iter) {
> > -		if (!contig)
> > +		if (page_offsets)
> >  			offset = page_offset(bvec.bv_page) + bvec.bv_offset;
> >  
> >  		if (!ordered) {
> > @@ -668,13 +663,14 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
> >  			BUG_ON(!ordered); /* Logic error */
> >  		}
> >  
> > -		nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info,
> > +		blockcount = BTRFS_BYTES_TO_BLKS(fs_info,
> >  						 bvec.bv_len + fs_info->sectorsize
> >  						 - 1);
> >  
> > -		for (i = 0; i < nr_sectors; i++) {
> > -			if (offset >= ordered->file_offset + ordered->num_bytes ||
> > -			    offset < ordered->file_offset) {
> > +		for (i = 0; i < blockcount; i++) {
> > +			if (!one_ordered &&
> > +			    (offset >= ordered->file_offset + ordered->num_bytes ||
> > +			     offset < ordered->file_offset)) {
> 
> Since you are changing this hunk, how about using the in_range macro:
> 
> if (!one_ordered && !in_range(offset, ordered->file_offset,
> ordered->num_bytes) { foo

Will do (although I don't like that that macro evaluates b and first
twice. Someone changing the code later might not notice that.)

> Though I think the "change the ordered extent now that we are working on
> a different range" code should be factored out in a separate function
> because currently it's somewhat breaking the flow of reading.
> 
> >  				unsigned long bytes_left;
> >  
> >  				sums->len = this_sum_bytes;
> > @@ -705,7 +701,8 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
> >  					    sums->sums + index);
> >  			kunmap_atomic(data);
> >  			index += fs_info->csum_size;
> > -			offset += fs_info->sectorsize;
> > +			if (!one_ordered)
> > +				offset += fs_info->sectorsize;
> 
> Instead of adding one additional conditional op can't offset always be
> incremented but in the case of one_ordered then the !in_range check
> should always be false i.e we won't be using the offset to lookup a new OE?

I did it conditionally so that it's clearer that the offset isn't needed
for the one_ordered case, but I can drop the check.

> >  			this_sum_bytes += fs_info->sectorsize;
> >  			total_bytes += fs_info->sectorsize;
> >  		}
> 
> 
> <snip>

Re: [PATCH v10 04/14] btrfs: add ram_bytes and offset to btrfs_ordered_extent

[Omar Sandoval]

On Fri, Aug 20, 2021 at 11:34:17AM +0300, Nikolay Borisov wrote:
> 
> 
> On 18.08.21 г. 0:06, Omar Sandoval wrote:
> > From: Omar Sandoval <osandov@fb.com>
> > 
> > Currently, we only create ordered extents when ram_bytes == num_bytes
> > and offset == 0. However, RWF_ENCODED writes may create extents which
> > only refer to a subset of the full unencoded extent, so we need to plumb
> 
> Can you give an example of such a case?

It happens whenever we have bookend extents. Here's an easy example:

$ dd if=/dev/zero of=file bs=12k count=1
1+0 records in
1+0 records out
12288 bytes (12 kB, 12 KiB) copied, 0.000202106 s, 60.8 MB/s
$ sync
$ truncate -s 8k file
$ sync
$ sudo ~/repos/osandov-linux/scripts/btrfs_map_physical ./file | column -ts$'\t'
FILE OFFSET  FILE SIZE  EXTENT OFFSET  EXTENT TYPE               LOGICAL SIZE  LOGICAL OFFSET  PHYSICAL SIZE  DEVID  PHYSICAL OFFSET
0            8192       0              regular,compression=zstd  12288         217173213184    4096           1      217173213184

The decompressed data is 12k, but we only use 8k for the file.

Re: [PATCH v10 07/14] btrfs: add definitions + documentation for encoded I/O ioctls

[Omar Sandoval]

On Fri, Aug 20, 2021 at 11:56:37AM +0300, Nikolay Borisov wrote:
> 
> 
> On 18.08.21 г. 0:06, Omar Sandoval wrote:
> > From: Omar Sandoval <osandov@fb.com>
> > 
> > In order to allow sending and receiving compressed data without
> > decompressing it, we need an interface to write pre-compressed data
> > directly to the filesystem and the matching interface to read compressed
> > data without decompressing it. This adds the definitions for ioctls to
> > do that and detailed explanations of how to use them.
> > 
> > Signed-off-by: Omar Sandoval <osandov@fb.com>
> > ---
> >  include/uapi/linux/btrfs.h | 132 +++++++++++++++++++++++++++++++++++++
> >  1 file changed, 132 insertions(+)
> > 
> > diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
> > index d7d3cfead056..95da52955894 100644
> > --- a/include/uapi/linux/btrfs.h
> > +++ b/include/uapi/linux/btrfs.h
> > @@ -861,6 +861,134 @@ struct btrfs_ioctl_get_subvol_rootref_args {
> >  		__u8 align[7];
> >  };
> >  
> > +/*
> > + * Data and metadata for an encoded read or write.
> > + *
> > + * Encoded I/O bypasses any encoding automatically done by the filesystem (e.g.,
> > + * compression). This can be used to read the compressed contents of a file or
> > + * write pre-compressed data directly to a file.
> > + *
> > + * BTRFS_IOC_ENCODED_READ and BTRFS_IOC_ENCODED_WRITE are essentially
> > + * preadv/pwritev with additional metadata about how the data is encoded and the
> > + * size of the unencoded data.
> > + *
> > + * BTRFS_IOC_ENCODED_READ fills the given iovecs with the encoded data, fills
> > + * the metadata fields, and returns the size of the encoded data. It reads one
> > + * extent per call. It can also read data which is not encoded.
> > + *
> > + * BTRFS_IOC_ENCODED_WRITE uses the metadata fields, writes the encoded data
> > + * from the iovecs, and returns the size of the encoded data. Note that the
> > + * encoded data is not validated when it is written; if it is not valid (e.g.,
> > + * it cannot be decompressed), then a subsequent read may return an error.
> > + *
> > + * Since the filesystem page cache contains decoded data, encoded I/O bypasses
> > + * the page cache. Encoded I/O requires CAP_SYS_ADMIN.
> > + */
> > +struct btrfs_ioctl_encoded_io_args {
> > +	/* Input parameters for both reads and writes. */
> > +
> > +	/*
> > +	 * iovecs containing encoded data.
> > +	 *
> > +	 * For reads, if the size of the encoded data is larger than the sum of
> > +	 * iov[n].iov_len for 0 <= n < iovcnt, then the ioctl fails with
> > +	 * ENOBUFS.
> > +	 *
> > +	 * For writes, the size of the encoded data is the sum of iov[n].iov_len
> > +	 * for 0 <= n < iovcnt. This must be less than 128 KiB (this limit may
> > +	 * increase in the future). This must also be less than or equal to
> > +	 * unencoded_len.
> > +	 */
> > +	const struct iovec __user *iov;
> > +	/* Number of iovecs. */
> > +	unsigned long iovcnt;
> > +	/*
> > +	 * Offset in file.
> > +	 *
> > +	 * For writes, must be aligned to the sector size of the filesystem.
> > +	 */
> > +	__s64 offset;
> > +	/* Currently must be zero. */
> > +	__u64 flags;
> > +
> > +	/*
> > +	 * For reads, the following members are filled in with the metadata for
> > +	 * the encoded data.
> > +	 * For writes, the following members must be set to the metadata for the
> > +	 * encoded data.
> > +	 */
> > +
> > +	/*
> > +	 * Length of the data in the file.
> > +	 *
> > +	 * Must be less than or equal to unencoded_len - unencoded_offset. For
> > +	 * writes, must be aligned to the sector size of the filesystem unless
> > +	 * the data ends at or beyond the current end of the file.
> > +	 */
> > +	__u64 len;
> > +	/*
> > +	 * Length of the unencoded (i.e., decrypted and decompressed) data.
> > +	 *
> > +	 * For writes, must be no more than 128 KiB (this limit may increase in
> > +	 * the future). If the unencoded data is actually longer than
> > +	 * unencoded_len, then it is truncated; if it is shorter, then it is
> > +	 * extended with zeroes.
> > +	 */
> > +	__u64 unencoded_len;
> > +	/*
> > +	 * Offset from the first byte of the unencoded data to the first byte of
> > +	 * logical data in the file.
> > +	 *
> > +	 * Must be less than unencoded_len.
> > +	 */
> > +	__u64 unencoded_offset;
> > +	/*
> > +	 * BTRFS_ENCODED_IO_COMPRESSION_* type.
> > +	 *
> > +	 * For writes, must not be BTRFS_ENCODED_IO_COMPRESSION_NONE.
> > +	 */
> > +	__u32 compression;
> > +	/* Currently always BTRFS_ENCODED_IO_ENCRYPTION_NONE. */
> > +	__u32 encryption;
> > +	/*
> > +	 * Reserved for future expansion.
> > +	 *
> > +	 * For reads, always returned as zero. Users should check for non-zero
> > +	 * bytes. If there are any, then the kernel has a newer version of this
> > +	 * structure with additional information that the user definition is
> > +	 * missing.
> > +	 *
> > +	 * For writes, must be zeroed.
> > +	 */
> > +	__u8 reserved[32];
> > +};
> > +
> > +/* Data is not compressed. */
> > +#define BTRFS_ENCODED_IO_COMPRESSION_NONE 0
> > +/* Data is compressed as a single zlib stream. */
> > +#define BTRFS_ENCODED_IO_COMPRESSION_ZLIB 1
> > +/*
> > + * Data is compressed as a single zstd frame with the windowLog compression
> > + * parameter set to no more than 17.
> > + */
> > +#define BTRFS_ENCODED_IO_COMPRESSION_ZSTD 2
> > +/*
> > + * Data is compressed page by page (using the page size indicated by the name of
> > + * the constant) with LZO1X and wrapped in the format documented in
> > + * fs/btrfs/lzo.c. For writes, the compression page size must match the
> > + * filesystem page size.
> > + */
> > +#define BTRFS_ENCODED_IO_COMPRESSION_LZO_4K 3
> > +#define BTRFS_ENCODED_IO_COMPRESSION_LZO_8K 4
> > +#define BTRFS_ENCODED_IO_COMPRESSION_LZO_16K 5
> > +#define BTRFS_ENCODED_IO_COMPRESSION_LZO_32K 6
> > +#define BTRFS_ENCODED_IO_COMPRESSION_LZO_64K 7
> > +#define BTRFS_ENCODED_IO_COMPRESSION_TYPES 8
> > +
> > +/* Data is not encrypted. */
> > +#define BTRFS_ENCODED_IO_ENCRYPTION_NONE 0
> > +#define BTRFS_ENCODED_IO_ENCRYPTION_TYPES 1
> 
> How about an enums for encryption/compression.

With #define, the user can use #ifdef to check if the constants are
defined and provide their own definitions if not (that's what I did in
the xfstests example programs). Another option is the enum+#define
pattern:

enum {
	BTRFS_ENCODED_IO_COMPRESSION_NONE,
#define BTRFS_ENCODED_IO_COMPRESSION_NONE BTRFS_ENCODED_IO_COMPRESSION_NONE
	BTRFS_ENCODED_IO_COMPRESSION_ZLIB,
#define BTRFS_ENCODED_IO_COMPRESSION_ZLIB BTRFS_ENCODED_IO_COMPRESSION_ZLIB
	BTRFS_ENCODED_IO_COMPRESSION_ZSTD,
#define BTRFS_ENCODED_IO_COMPRESSION_ZSTD BTRFS_ENCODED_IO_COMPRESSION_ZSTD
	BTRFS_ENCODED_IO_COMPRESSION_LZO_4K,
#define BTRFS_ENCODED_IO_COMPRESSION_LZO_4K BTRFS_ENCODED_IO_COMPRESSION_LZO_4K
	BTRFS_ENCODED_IO_COMPRESSION_LZO_8K,
#define BTRFS_ENCODED_IO_COMPRESSION_LZO_8K BTRFS_ENCODED_IO_COMPRESSION_LZO_8K
	BTRFS_ENCODED_IO_COMPRESSION_LZO_16K,
#define BTRFS_ENCODED_IO_COMPRESSION_LZO_16K BTRFS_ENCODED_IO_COMPRESSION_LZO_16K
	BTRFS_ENCODED_IO_COMPRESSION_LZO_32K,
#define BTRFS_ENCODED_IO_COMPRESSION_LZO_32K BTRFS_ENCODED_IO_COMPRESSION_LZO_32K
	BTRFS_ENCODED_IO_COMPRESSION_LZO_64K,
#define BTRFS_ENCODED_IO_COMPRESSION_LZO_64K BTRFS_ENCODED_IO_COMPRESSION_LZO_64K
	BTRFS_ENCODED_IO_COMPRESSION_TYPES,
};

But that seems to confuse people. I don't feel strongly one way or
another.

Re: [PATCH v10 08/14] btrfs: add BTRFS_IOC_ENCODED_READ

[Omar Sandoval]

On Fri, Aug 20, 2021 at 03:30:02PM +0300, Nikolay Borisov wrote:
> 
> 
> On 18.08.21 г. 0:06, Omar Sandoval wrote:
> > From: Omar Sandoval <osandov@fb.com>
> > 
> > There are 4 main cases:
> > 
> > 1. Inline extents: we copy the data straight out of the extent buffer.
> > 2. Hole/preallocated extents: we fill in zeroes.
> > 3. Regular, uncompressed extents: we read the sectors we need directly
> >    from disk.
> > 4. Regular, compressed extents: we read the entire compressed extent
> >    from disk and indicate what subset of the decompressed extent is in
> >    the file.
> > 
> > This initial implementation simplifies a few things that can be improved
> > in the future:
> > 
> > - We hold the inode lock during the operation.
> > - Cases 1, 3, and 4 allocate temporary memory to read into before
> >   copying out to userspace.
> > - We don't do read repair, because it turns out that read repair is
> >   currently broken for compressed data.
> > 
> > Signed-off-by: Omar Sandoval <osandov@fb.com>
> > ---
> >  fs/btrfs/ctree.h |   4 +
> >  fs/btrfs/inode.c | 489 +++++++++++++++++++++++++++++++++++++++++++++++
> >  fs/btrfs/ioctl.c | 111 +++++++++++
> >  3 files changed, 604 insertions(+)
> > 
> > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> > index 973616d80080..b68d8ea42f6e 100644
> > --- a/fs/btrfs/ctree.h
> > +++ b/fs/btrfs/ctree.h
> > @@ -3219,6 +3219,10 @@ int btrfs_writepage_cow_fixup(struct page *page);
> >  void btrfs_writepage_endio_finish_ordered(struct btrfs_inode *inode,
> >  					  struct page *page, u64 start,
> >  					  u64 end, bool uptodate);
> > +struct btrfs_ioctl_encoded_io_args;
> > +ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter,
> > +			   struct btrfs_ioctl_encoded_io_args *encoded);
> > +
> >  extern const struct dentry_operations btrfs_dentry_operations;
> >  extern const struct iomap_ops btrfs_dio_iomap_ops;
> >  extern const struct iomap_dio_ops btrfs_dio_ops;
> > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> > index 0b5ff14aa7fd..6d7fae859fb5 100644
> > --- a/fs/btrfs/inode.c
> > +++ b/fs/btrfs/inode.c
> > @@ -10496,6 +10496,495 @@ void btrfs_set_range_writeback(struct btrfs_inode *inode, u64 start, u64 end)
> >  	}
> >  }
> >  
> > +static int btrfs_encoded_io_compression_from_extent(int compress_type)
> > +{
> > +	switch (compress_type) {
> > +	case BTRFS_COMPRESS_NONE:
> > +		return BTRFS_ENCODED_IO_COMPRESSION_NONE;
> > +	case BTRFS_COMPRESS_ZLIB:
> > +		return BTRFS_ENCODED_IO_COMPRESSION_ZLIB;
> > +	case BTRFS_COMPRESS_LZO:
> > +		/*
> > +		 * The LZO format depends on the page size. 64k is the maximum
> > +		 * sectorsize (and thus page size) that we support.
> > +		 */
> > +		if (PAGE_SIZE < SZ_4K || PAGE_SIZE > SZ_64K)
> > +			return -EINVAL;
> > +		return BTRFS_ENCODED_IO_COMPRESSION_LZO_4K + (PAGE_SHIFT - 12);
> > +	case BTRFS_COMPRESS_ZSTD:
> > +		return BTRFS_ENCODED_IO_COMPRESSION_ZSTD;
> > +	default:
> > +		return -EUCLEAN;
> > +	}
> > +}
> > +
> > +static ssize_t btrfs_encoded_read_inline(
> > +				struct kiocb *iocb,
> > +				struct iov_iter *iter, u64 start,
> > +				u64 lockend,
> > +				struct extent_state **cached_state,
> > +				u64 extent_start, size_t count,
> > +				struct btrfs_ioctl_encoded_io_args *encoded,
> > +				bool *unlocked)
> > +{
> > +	struct inode *inode = file_inode(iocb->ki_filp);
> > +	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
> > +	struct btrfs_path *path;
> > +	struct extent_buffer *leaf;
> > +	struct btrfs_file_extent_item *item;
> > +	u64 ram_bytes;
> > +	unsigned long ptr;
> > +	void *tmp;
> > +	ssize_t ret;
> > +
> > +	path = btrfs_alloc_path();
> > +	if (!path) {
> > +		ret = -ENOMEM;
> > +		goto out;
> > +	}
> > +	ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root, path,
> > +				       btrfs_ino(BTRFS_I(inode)), extent_start,
> > +				       0);
> > +	if (ret) {
> > +		if (ret > 0) {
> > +			/* The extent item disappeared? */
> > +			ret = -EIO;
> > +		}
> > +		goto out;
> > +	}
> > +	leaf = path->nodes[0];
> > +	item = btrfs_item_ptr(leaf, path->slots[0],
> > +			      struct btrfs_file_extent_item);
> > +
> > +	ram_bytes = btrfs_file_extent_ram_bytes(leaf, item);
> > +	ptr = btrfs_file_extent_inline_start(item);
> > +
> > +	encoded->len = (min_t(u64, extent_start + ram_bytes, inode->i_size) -
> > +			iocb->ki_pos);
> > +	ret = btrfs_encoded_io_compression_from_extent(
> > +				 btrfs_file_extent_compression(leaf, item));
> > +	if (ret < 0)
> > +		goto out;
> > +	encoded->compression = ret;
> > +	if (encoded->compression) {
> > +		size_t inline_size;
> > +
> > +		inline_size = btrfs_file_extent_inline_item_len(leaf,
> > +						btrfs_item_nr(path->slots[0]));
> > +		if (inline_size > count) {
> > +			ret = -ENOBUFS;
> > +			goto out;
> > +		}
> > +		count = inline_size;
> > +		encoded->unencoded_len = ram_bytes;
> > +		encoded->unencoded_offset = iocb->ki_pos - extent_start;
> > +	} else {
> > +		encoded->len = encoded->unencoded_len = count =
> > +			min_t(u64, count, encoded->len);
> > +		ptr += iocb->ki_pos - extent_start;
> > +	}
> > +
> > +	tmp = kmalloc(count, GFP_NOFS);
> > +	if (!tmp) {
> > +		ret = -ENOMEM;
> > +		goto out;
> > +	}
> > +	read_extent_buffer(leaf, tmp, ptr, count);
> > +	btrfs_release_path(path);
> > +	unlock_extent_cached(io_tree, start, lockend, cached_state);
> > +	inode_unlock_shared(inode);
> > +	*unlocked = true;
> > +
> > +	ret = copy_to_iter(tmp, count, iter);
> > +	if (ret != count)
> > +		ret = -EFAULT;
> > +	kfree(tmp);
> > +out:
> > +	btrfs_free_path(path);
> > +	return ret;
> > +}
> > +
> > +struct btrfs_encoded_read_private {
> > +	struct inode *inode;
> > +	wait_queue_head_t wait;
> > +	atomic_t pending;
> > +	blk_status_t status;
> > +	bool skip_csum;
> > +};
> > +
> > +static blk_status_t submit_encoded_read_bio(struct inode *inode,
> > +					    struct bio *bio, int mirror_num,
> > +					    unsigned long bio_flags)
> > +{
> > +	struct btrfs_encoded_read_private *priv = bio->bi_private;
> > +	struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
> > +	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> > +	blk_status_t ret;
> > +
> > +	if (!priv->skip_csum) {
> > +		ret = btrfs_lookup_bio_sums(inode, bio, NULL);
> > +		if (ret)
> > +			return ret;
> > +	}
> > +
> > +	ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DATA);
> > +	if (ret) {
> > +		btrfs_io_bio_free_csum(io_bio);
> > +		return ret;
> > +	}
> > +
> > +	atomic_inc(&priv->pending);
> > +	ret = btrfs_map_bio(fs_info, bio, mirror_num);
> > +	if (ret) {
> > +		atomic_dec(&priv->pending);
> > +		btrfs_io_bio_free_csum(io_bio);
> > +	}
> > +	return ret;
> > +}
> > +
> > +static blk_status_t btrfs_encoded_read_check_bio(struct btrfs_io_bio *io_bio)
> > +{
> > +	const bool uptodate = io_bio->bio.bi_status == BLK_STS_OK;
> > +	struct btrfs_encoded_read_private *priv = io_bio->bio.bi_private;
> > +	struct inode *inode = priv->inode;
> > +	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> > +	u32 sectorsize = fs_info->sectorsize;
> > +	struct bio_vec *bvec;
> > +	struct bvec_iter_all iter_all;
> > +	u64 start = io_bio->logical;
> > +	u32 bio_offset = 0;
> > +
> > +	if (priv->skip_csum || !uptodate)
> > +		return io_bio->bio.bi_status;
> > +
> > +	bio_for_each_segment_all(bvec, &io_bio->bio, iter_all) {
> > +		unsigned int i, nr_sectors, pgoff;
> > +
> > +		nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);
> > +		pgoff = bvec->bv_offset;
> > +		for (i = 0; i < nr_sectors; i++) {
> > +			ASSERT(pgoff < PAGE_SIZE);
> > +			if (check_data_csum(inode, io_bio, bio_offset,
> > +					    bvec->bv_page, pgoff, start))
> > +				return BLK_STS_IOERR;
> > +			start += sectorsize;
> > +			bio_offset += sectorsize;
> > +			pgoff += sectorsize;
> > +		}
> > +	}
> > +	return BLK_STS_OK;
> > +}
> > +
> > +static void btrfs_encoded_read_endio(struct bio *bio)
> > +{
> > +	struct btrfs_encoded_read_private *priv = bio->bi_private;
> > +	struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
> > +	blk_status_t status;
> > +
> > +	status = btrfs_encoded_read_check_bio(io_bio);
> > +	if (status) {
> > +		/*
> > +		 * The memory barrier implied by the atomic_dec_return() here
> > +		 * pairs with the memory barrier implied by the
> > +		 * atomic_dec_return() or io_wait_event() in
> > +		 * btrfs_encoded_read_regular_fill_pages() to ensure that this
> > +		 * write is observed before the load of status in
> > +		 * btrfs_encoded_read_regular_fill_pages().
> > +		 */
> > +		WRITE_ONCE(priv->status, status);
> > +	}
> > +	if (!atomic_dec_return(&priv->pending))
> > +		wake_up(&priv->wait);
> > +	btrfs_io_bio_free_csum(io_bio);
> > +	bio_put(bio);
> > +}
> > +
> > +static int btrfs_encoded_read_regular_fill_pages(struct inode *inode, u64 offset,
> > +						 u64 disk_io_size, struct page **pages)
> > +{
> > +	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> > +	struct btrfs_encoded_read_private priv = {
> > +		.inode = inode,
> > +		.pending = ATOMIC_INIT(1),
> > +		.skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM,
> > +	};
> > +	unsigned long i = 0;
> > +	u64 cur = 0;
> > +	int ret;
> > +
> > +	init_waitqueue_head(&priv.wait);
> > +	/*
> > +	 * Submit bios for the extent, splitting due to bio or stripe limits as
> > +	 * necessary.
> > +	 */
> > +	while (cur < disk_io_size) {
> > +		struct extent_map *em;
> > +		struct btrfs_io_geometry geom;
> > +		struct bio *bio = NULL;
> > +		u64 remaining;
> > +
> > +		em = btrfs_get_chunk_map(fs_info, offset + cur,
> > +					 disk_io_size - cur);
> > +		if (IS_ERR(em)) {
> > +			ret = PTR_ERR(em);
> > +		} else {
> > +			ret = btrfs_get_io_geometry(fs_info, em, BTRFS_MAP_READ,
> > +						    offset + cur, &geom);
> > +			free_extent_map(em);
> > +		}
> > +		if (ret) {
> > +			WRITE_ONCE(priv.status, errno_to_blk_status(ret));
> > +			break;
> > +		}
> > +		remaining = min(geom.len, disk_io_size - cur);
> > +		while (bio || remaining) {
> > +			size_t bytes = min_t(u64, remaining, PAGE_SIZE);
> > +
> > +			if (!bio) {
> > +				bio = btrfs_bio_alloc(offset + cur);
> > +				bio->bi_end_io = btrfs_encoded_read_endio;
> > +				bio->bi_private = &priv;
> > +				bio->bi_opf = REQ_OP_READ;
> > +			}
> > +
> > +			if (!bytes ||
> > +			    bio_add_page(bio, pages[i], bytes, 0) < bytes) {
> > +				blk_status_t status;
> > +
> > +				status = submit_encoded_read_bio(inode, bio, 0,
> > +								 0);
> > +				if (status) {
> > +					WRITE_ONCE(priv.status, status);
> > +					bio_put(bio);
> > +					goto out;
> > +				}
> > +				bio = NULL;
> > +				continue;
> > +			}
> > +
> > +			i++;
> > +			cur += bytes;
> > +			remaining -= bytes;
> > +		}
> > +	}
> > +
> > +out:
> > +	if (atomic_dec_return(&priv.pending))
> > +		io_wait_event(priv.wait, !atomic_read(&priv.pending));
> > +	/* See btrfs_encoded_read_endio() for ordering. */
> > +	return blk_status_to_errno(READ_ONCE(priv.status));
> > +}
> > +
> > +static ssize_t btrfs_encoded_read_regular(struct kiocb *iocb,
> > +					  struct iov_iter *iter,
> > +					  u64 start, u64 lockend,
> > +					  struct extent_state **cached_state,
> > +					  u64 offset, u64 disk_io_size,
> > +					  size_t count, bool compressed,
> > +					  bool *unlocked)
> > +{
> > +	struct inode *inode = file_inode(iocb->ki_filp);
> > +	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
> > +	struct page **pages;
> > +	unsigned long nr_pages, i;
> > +	u64 cur;
> > +	size_t page_offset;
> > +	ssize_t ret;
> > +
> > +	nr_pages = DIV_ROUND_UP(disk_io_size, PAGE_SIZE);
> > +	pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
> > +	if (!pages)
> > +		return -ENOMEM;
> > +	for (i = 0; i < nr_pages; i++) {
> > +		pages[i] = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
> > +		if (!pages[i]) {
> > +			ret = -ENOMEM;
> > +			goto out;
> > +		}
> > +	}
> > +
> > +	ret = btrfs_encoded_read_regular_fill_pages(inode, offset, disk_io_size,
> > +						    pages);
> > +	if (ret)
> > +		goto out;
> > +
> > +	unlock_extent_cached(io_tree, start, lockend, cached_state);
> > +	inode_unlock_shared(inode);
> > +	*unlocked = true;
> > +
> > +	if (compressed) {
> > +		i = 0;
> > +		page_offset = 0;
> > +	} else {
> > +		i = (iocb->ki_pos - start) >> PAGE_SHIFT;
> > +		page_offset = (iocb->ki_pos - start) & (PAGE_SIZE - 1);
> > +	}
> > +	cur = 0;
> > +	while (cur < count) {
> > +		size_t bytes = min_t(size_t, count - cur,
> > +				     PAGE_SIZE - page_offset);
> > +
> > +		if (copy_page_to_iter(pages[i], page_offset, bytes,
> > +				      iter) != bytes) {
> > +			ret = -EFAULT;
> > +			goto out;
> > +		}
> > +		i++;
> > +		cur += bytes;
> > +		page_offset = 0;
> > +	}
> > +	ret = count;
> > +out:
> > +	for (i = 0; i < nr_pages; i++) {
> > +		if (pages[i])
> > +			__free_page(pages[i]);
> > +	}
> > +	kfree(pages);
> > +	return ret;
> > +}
> > +
> > +ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter,
> > +			   struct btrfs_ioctl_encoded_io_args *encoded)
> > +{
> > +	struct inode *inode = file_inode(iocb->ki_filp);
> > +	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> > +	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
> > +	ssize_t ret;
> > +	size_t count = iov_iter_count(iter);
> > +	u64 start, lockend, offset, disk_io_size;
> > +	struct extent_state *cached_state = NULL;
> > +	struct extent_map *em;
> > +	bool unlocked = false;
> > +
> > +	file_accessed(iocb->ki_filp);
> > +
> > +	inode_lock_shared(inode);
> > +
> > +	if (iocb->ki_pos >= inode->i_size) {
> > +		inode_unlock_shared(inode);
> > +		return 0;
> 
> Don't we need to signal beyond EOF reads somehow. As it stands returning
> 0 means returning zeroed portion of btrfs_ioctl_encoded_io_args to user
> space?

If you do a normal read/pread beyond EOF, the syscall returns 0,
indicating that there are no bytes to read at that offset. We're doing
the same thing here: returning 0 means 0 compressed bytes were read, and
setting btrfs_ioctl_encoded_io_args::len to 0 means 0 bytes in the file
were read.

> > +	}
> > +	start = ALIGN_DOWN(iocb->ki_pos, fs_info->sectorsize);
> > +	/*
> > +	 * We don't know how long the extent containing iocb->ki_pos is, but if
> > +	 * it's compressed we know that it won't be longer than this.
> > +	 */
> > +	lockend = start + BTRFS_MAX_UNCOMPRESSED - 1;
> > +
> > +	for (;;) {
> > +		struct btrfs_ordered_extent *ordered;
> > +
> > +		ret = btrfs_wait_ordered_range(inode, start,
> > +					       lockend - start + 1);
> > +		if (ret)
> > +			goto out_unlock_inode;
> > +		lock_extent_bits(io_tree, start, lockend, &cached_state);
> > +		ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
> > +						     lockend - start + 1);
> > +		if (!ordered)
> > +			break;
> > +		btrfs_put_ordered_extent(ordered);
> > +		unlock_extent_cached(io_tree, start, lockend, &cached_state);
> > +		cond_resched();
> > +	}
> Can't you simply use btrfs_lock_and_flush_ordered_range, the major
> difference is btrfs_wait_ordered_range basically instantiates any
> pending delalloc, whilst btrfs_lock_and_flush_ordered_range returns with
> any, already-instantiated OE run to completion and the range locked ?

Josef asked this before here:
https://lore.kernel.org/linux-btrfs/1286c8c7-521f-d60c-97d5-c42dc57ce6a9@toxicpanda.com/.
It's not sufficient to run instantiated ordered extents. We actually
need to flush pending buffered writes.

> > +
> > +	em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start,
> > +			      lockend - start + 1);
> > +	if (IS_ERR(em)) {
> > +		ret = PTR_ERR(em);
> > +		goto out_unlock_extent;
> > +	}
> > +
> > +	if (em->block_start == EXTENT_MAP_INLINE) {
> > +		u64 extent_start = em->start;
> > +
> > +		/*
> > +		 * For inline extents we get everything we need out of the
> > +		 * extent item.
> > +		 */
> > +		free_extent_map(em);
> > +		em = NULL;
> > +		ret = btrfs_encoded_read_inline(iocb, iter, start, lockend,
> > +						&cached_state, extent_start,
> > +						count, encoded, &unlocked);
> > +		goto out;
> > +	}
> > +
> > +	/*
> > +	 * We only want to return up to EOF even if the extent extends beyond
> > +	 * that.
> > +	 */
> > +	encoded->len = (min_t(u64, extent_map_end(em), inode->i_size) -
> > +			iocb->ki_pos);
> > +	if (em->block_start == EXTENT_MAP_HOLE ||
> > +	    test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
> > +		offset = EXTENT_MAP_HOLE;
> > +		encoded->len = encoded->unencoded_len = count =
> > +			min_t(u64, count, encoded->len);
> > +	} else if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
> > +		offset = em->block_start;
> > +		/*
> > +		 * Bail if the buffer isn't large enough to return the whole
> > +		 * compressed extent.
> > +		 */
> > +		if (em->block_len > count) {
> > +			ret = -ENOBUFS;
> > +			goto out_em;
> > +		}
> > +		disk_io_size = count = em->block_len;
> > +		encoded->unencoded_len = em->ram_bytes;
> > +		encoded->unencoded_offset = iocb->ki_pos - em->orig_start;
> > +		ret = btrfs_encoded_io_compression_from_extent(
> > +							     em->compress_type);
> > +		if (ret < 0)
> > +			goto out_em;
> > +		encoded->compression = ret;
> > +	} else {
> > +		offset = em->block_start + (start - em->start);
> > +		if (encoded->len > count)
> > +			encoded->len = count;
> > +		/*
> > +		 * Don't read beyond what we locked. This also limits the page
> > +		 * allocations that we'll do.
> > +		 */
> > +		disk_io_size = min(lockend + 1,
> > +				   iocb->ki_pos + encoded->len) - start;
> > +		encoded->len = encoded->unencoded_len = count =
> > +			start + disk_io_size - iocb->ki_pos;
> > +		disk_io_size = ALIGN(disk_io_size, fs_info->sectorsize);
> > +	}
> > +	free_extent_map(em);
> > +	em = NULL;
> > +
> > +	if (offset == EXTENT_MAP_HOLE) {
> > +		unlock_extent_cached(io_tree, start, lockend, &cached_state);
> > +		inode_unlock_shared(inode);
> > +		unlocked = true;
> > +		ret = iov_iter_zero(count, iter);
> > +		if (ret != count)
> > +			ret = -EFAULT;
> > +	} else {
> > +		ret = btrfs_encoded_read_regular(iocb, iter, start, lockend,
> > +						 &cached_state, offset,
> > +						 disk_io_size, count,
> > +						 encoded->compression,
> > +						 &unlocked);
> > +	}
> > +
> > +out:
> > +	if (ret >= 0)
> > +		iocb->ki_pos += encoded->len;
> > +out_em:
> > +	free_extent_map(em);
> > +out_unlock_extent:
> > +	if (!unlocked)
> > +		unlock_extent_cached(io_tree, start, lockend, &cached_state);
> > +out_unlock_inode:
> > +	if (!unlocked)
> > +		inode_unlock_shared(inode);
> > +	return ret;
> > +}
> > +
> >  #ifdef CONFIG_SWAP
> >  /*
> >   * Add an entry indicating a block group or device which is pinned by a
> 
> <snip>
> 
> >  /* Mask out flags that are inappropriate for the given type of inode. */
> > @@ -4887,6 +4904,94 @@ static int _btrfs_ioctl_send(struct file *file, void __user *argp, bool compat)
> >  	return ret;
> >  }
> >  
> > +static int btrfs_ioctl_encoded_read(struct file *file, void __user *argp,
> > +				    bool compat)
> > +{
> > +	struct btrfs_ioctl_encoded_io_args args;
> 
> nit: If you make this args = {}; you guarantee it's zeroed out then you
> can get rid of the ugly memset further down.

Sure, I'll do that.

Re: [PATCH v10 09/14] btrfs: add BTRFS_IOC_ENCODED_WRITE

[Omar Sandoval]

On Fri, Aug 20, 2021 at 04:44:26PM +0300, Nikolay Borisov wrote:
> 
> 
> On 18.08.21 г. 0:06, Omar Sandoval wrote:
> > From: Omar Sandoval <osandov@fb.com>
> > 
> > The implementation resembles direct I/O: we have to flush any ordered
> > extents, invalidate the page cache, and do the io tree/delalloc/extent
> > map/ordered extent dance. From there, we can reuse the compression code
> > with a minor modification to distinguish the write from writeback. This
> > also creates inline extents when possible.
> > 
> > Signed-off-by: Omar Sandoval <osandov@fb.com>
> 
> <snip>
> 
> >   * Add an entry indicating a block group or device which is pinned by a
> > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> > index 7a0a9c752624..13a0a65c6a43 100644
> > --- a/fs/btrfs/ioctl.c
> > +++ b/fs/btrfs/ioctl.c
> > @@ -103,6 +103,8 @@ struct btrfs_ioctl_encoded_io_args_32 {
> >  
> >  #define BTRFS_IOC_ENCODED_READ_32 _IOR(BTRFS_IOCTL_MAGIC, 64, \
> >  				       struct btrfs_ioctl_encoded_io_args_32)
> > +#define BTRFS_IOC_ENCODED_WRITE_32 _IOW(BTRFS_IOCTL_MAGIC, 64, \
> > +					struct btrfs_ioctl_encoded_io_args_32)
> >  #endif
> >  
> >  /* Mask out flags that are inappropriate for the given type of inode. */
> > @@ -4992,6 +4994,102 @@ static int btrfs_ioctl_encoded_read(struct file *file, void __user *argp,
> >  	return ret;
> >  }
> >  
> > +static int btrfs_ioctl_encoded_write(struct file *file, void __user *argp,
> > +				     bool compat)
> > +{
> > +	struct btrfs_ioctl_encoded_io_args args;
> > +	struct iovec iovstack[UIO_FASTIOV];
> > +	struct iovec *iov = iovstack;
> > +	struct iov_iter iter;
> > +	loff_t pos;
> > +	struct kiocb kiocb;
> > +	ssize_t ret;
> > +
> > +	if (!capable(CAP_SYS_ADMIN)) {
> > +		ret = -EPERM;
> > +		goto out_acct;
> > +	}
> > +
> > +	if (!(file->f_mode & FMODE_WRITE)) {
> > +		ret = -EBADF;
> > +		goto out_acct;
> > +	}
> > +
> > +	if (compat) {
> > +#if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
> > +		struct btrfs_ioctl_encoded_io_args_32 args32;
> > +
> > +		if (copy_from_user(&args32, argp, sizeof(args32))) {
> > +			ret = -EFAULT;
> > +			goto out_acct;
> > +		}
> > +		args.iov = compat_ptr(args32.iov);
> > +		args.iovcnt = args.iovcnt;
> > +		memcpy(&args.offset, &args32.offset,
> > +		       sizeof(args) -
> > +		       offsetof(struct btrfs_ioctl_encoded_io_args, offset));
> > +#else
> > +		return -ENOTTY;
> > +#endif
> > +	} else {
> > +		if (copy_from_user(&args, argp, sizeof(args))) {
> > +			ret = -EFAULT;
> > +			goto out_acct;
> > +		}
> > +	}
> > +
> > +	ret = -EINVAL;
> > +	if (args.flags != 0)
> > +		goto out_acct;
> > +	if (memchr_inv(args.reserved, 0, sizeof(args.reserved)))
> > +		goto out_acct;
> > +	if (args.compression == BTRFS_ENCODED_IO_COMPRESSION_NONE &&
> > +	    args.encryption == BTRFS_ENCODED_IO_ENCRYPTION_NONE)
> 
> Do you intend on supporting encrypted data writeout in the future, given
> that in btrfs_do_encoded_write EINVAL is returned if the data to be
> written is encrypted? If not then this check could be moved earlier to
> fail fast.

We probably want to support it at some point in the future, yes.

> > @@ -5138,9 +5236,13 @@ long btrfs_ioctl(struct file *file, unsigned int
> >  		return fsverity_ioctl_measure(file, argp);
> >  	case BTRFS_IOC_ENCODED_READ:
> >  		return btrfs_ioctl_encoded_read(file, argp, false);
> > +	case BTRFS_IOC_ENCODED_WRITE:
> > +		return btrfs_ioctl_encoded_write(file, argp, false);
> >  #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
> >  	case BTRFS_IOC_ENCODED_READ_32:
> >  		return btrfs_ioctl_encoded_read(file, argp, true);
> > +	case BTRFS_IOC_ENCODED_WRITE_32:
> > +		return btrfs_ioctl_encoded_write(file, argp, true);
> >  #endif
> >  	}
> >  
> > diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
> > index 550c34fa0e6d..180f302dee93 100644
> > --- a/fs/btrfs/ordered-data.c
> > +++ b/fs/btrfs/ordered-data.c
> > @@ -521,9 +521,15 @@ void btrfs_remove_ordered_extent(struct btrfs_inode *btrfs_inode,
> >  	spin_lock(&btrfs_inode->lock);
> >  	btrfs_mod_outstanding_extents(btrfs_inode, -1);
> >  	spin_unlock(&btrfs_inode->lock);
> > -	if (root != fs_info->tree_root)
> > -		btrfs_delalloc_release_metadata(btrfs_inode, entry->num_bytes,
> > -						false);
> > +	if (root != fs_info->tree_root) {
> > +		u64 release;
> > +
> > +		if (test_bit(BTRFS_ORDERED_ENCODED, &entry->flags))
> > +			release = entry->disk_num_bytes;
> > +		else
> > +			release = entry->num_bytes;
> > +		btrfs_delalloc_release_metadata(btrfs_inode, release, false);
> > +	}
> >  
> >  	percpu_counter_add_batch(&fs_info->ordered_bytes, -entry->num_bytes,
> >  				 fs_info->delalloc_batch);
> > diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
> > index 0feb0c29839e..04588ccad34c 100644
> > --- a/fs/btrfs/ordered-data.h
> > +++ b/fs/btrfs/ordered-data.h
> > @@ -74,6 +74,8 @@ enum {
> >  	BTRFS_ORDERED_LOGGED_CSUM,
> >  	/* We wait for this extent to complete in the current transaction */
> >  	BTRFS_ORDERED_PENDING,
> > +	/* RWF_ENCODED I/O */
> 
> nit: RWF_ENCODED is no longer, we simply have ioctl-based encoded io. So
> this needs to be renamed to avoid confusion for people not necessarily
> faimilar with the development history of the feature.

Good catch, thanks.

Re: [PATCH v10 06/14] btrfs: optionally extend i_size in cow_file_range_inline()

[Omar Sandoval]

On Fri, Aug 20, 2021 at 05:13:34PM +0800, Qu Wenruo wrote:
> 
> 
> On 2021/8/20 下午4:51, Nikolay Borisov wrote:
> > 
> > 
> > On 18.08.21 г. 0:06, Omar Sandoval wrote:
> > > From: Omar Sandoval <osandov@fb.com>
> > > 
> > > Currently, an inline extent is always created after i_size is extended
> > > from btrfs_dirty_pages(). However, for encoded writes, we only want to
> > > update i_size after we successfully created the inline extent.
> 
> To me, the idea of write first then update isize is just going to cause
> tons of inline extent related prblems.
> 
> The current example is falloc, which only update the isize after the
> falloc finishes.
> 
> This behavior has already bothered me quite a lot, as it can easily
> create mixed inline and regular extents.

Do you have an example of how this would happen? I have the inode and
extent bits locked during an encoded write, and I see that fallocate
does the same.

> Can't we remember the old isize (with proper locking), enlarge isize
> (with holes filled), do the write.
> 
> If something wrong happened, we truncate the isize back to its old isize.
> 
> > > Add an
> > > update_i_size parameter to cow_file_range_inline() and
> > > insert_inline_extent() and pass in the size of the extent rather than
> > > determining it from i_size. Since the start parameter is always passed
> > > as 0, get rid of it and simplify the logic in these two functions. While
> > > we're here, let's document the requirements for creating an inline
> > > extent.
> > > 
> > > Reviewed-by: Josef Bacik <josef@toxicpanda.com>
> > > Signed-off-by: Omar Sandoval <osandov@fb.com>
> > > ---
> > >   fs/btrfs/inode.c | 100 +++++++++++++++++++++++------------------------
> > >   1 file changed, 48 insertions(+), 52 deletions(-)
> > > 
> > > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> > > index 708d8ab098bc..0b5ff14aa7fd 100644
> > > --- a/fs/btrfs/inode.c
> > > +++ b/fs/btrfs/inode.c
> > > @@ -236,9 +236,10 @@ static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
> > >   static int insert_inline_extent(struct btrfs_trans_handle *trans,
> > >   				struct btrfs_path *path, bool extent_inserted,
> > >   				struct btrfs_root *root, struct inode *inode,
> > > -				u64 start, size_t size, size_t compressed_size,
> > > +				size_t size, size_t compressed_size,
> > >   				int compress_type,
> > > -				struct page **compressed_pages)
> > > +				struct page **compressed_pages,
> > > +				bool update_i_size)
> > >   {
> > >   	struct extent_buffer *leaf;
> > >   	struct page *page = NULL;
> > > @@ -247,7 +248,7 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
> > >   	struct btrfs_file_extent_item *ei;
> > >   	int ret;
> > >   	size_t cur_size = size;
> > > -	unsigned long offset;
> > > +	u64 i_size;
> > > 
> > >   	ASSERT((compressed_size > 0 && compressed_pages) ||
> > >   	       (compressed_size == 0 && !compressed_pages));
> > > @@ -260,7 +261,7 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
> > >   		size_t datasize;
> > > 
> > >   		key.objectid = btrfs_ino(BTRFS_I(inode));
> > > -		key.offset = start;
> > > +		key.offset = 0;
> > >   		key.type = BTRFS_EXTENT_DATA_KEY;
> > > 
> > >   		datasize = btrfs_file_extent_calc_inline_size(cur_size);
> > > @@ -297,12 +298,10 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
> > >   		btrfs_set_file_extent_compression(leaf, ei,
> > >   						  compress_type);
> > >   	} else {
> > > -		page = find_get_page(inode->i_mapping,
> > > -				     start >> PAGE_SHIFT);
> > > +		page = find_get_page(inode->i_mapping, 0);
> > >   		btrfs_set_file_extent_compression(leaf, ei, 0);
> > >   		kaddr = kmap_atomic(page);
> > > -		offset = offset_in_page(start);
> > > -		write_extent_buffer(leaf, kaddr + offset, ptr, size);
> > > +		write_extent_buffer(leaf, kaddr, ptr, size);
> > >   		kunmap_atomic(kaddr);
> > >   		put_page(page);
> > >   	}
> > > @@ -313,8 +312,8 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
> > >   	 * We align size to sectorsize for inline extents just for simplicity
> > >   	 * sake.
> > >   	 */
> > > -	size = ALIGN(size, root->fs_info->sectorsize);
> > > -	ret = btrfs_inode_set_file_extent_range(BTRFS_I(inode), start, size);
> > > +	ret = btrfs_inode_set_file_extent_range(BTRFS_I(inode), 0,
> > > +					ALIGN(size, root->fs_info->sectorsize));
> > >   	if (ret)
> > >   		goto fail;
> > > 
> > > @@ -327,7 +326,13 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
> > >   	 * before we unlock the pages.  Otherwise we
> > >   	 * could end up racing with unlink.
> > >   	 */
> > > -	BTRFS_I(inode)->disk_i_size = inode->i_size;
> > > +	i_size = i_size_read(inode);
> > > +	if (update_i_size && size > i_size) {
> > > +		i_size_write(inode, size);
> > > +		i_size = size;
> > > +	}
> > > +	BTRFS_I(inode)->disk_i_size = i_size;
> > > +
> > >   fail:
> > >   	return ret;
> > >   }
> > > @@ -338,35 +343,31 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
> > >    * does the checks required to make sure the data is small enough
> > >    * to fit as an inline extent.
> > >    */
> > > -static noinline int cow_file_range_inline(struct btrfs_inode *inode, u64 start,
> > > -					  u64 end, size_t compressed_size,
> > > +static noinline int cow_file_range_inline(struct btrfs_inode *inode, u64 size,
> > > +					  size_t compressed_size,
> > >   					  int compress_type,
> > > -					  struct page **compressed_pages)
> > > +					  struct page **compressed_pages,
> > > +					  bool update_i_size)
> > >   {
> > >   	struct btrfs_drop_extents_args drop_args = { 0 };
> > >   	struct btrfs_root *root = inode->root;
> > >   	struct btrfs_fs_info *fs_info = root->fs_info;
> > >   	struct btrfs_trans_handle *trans;
> > > -	u64 isize = i_size_read(&inode->vfs_inode);
> > > -	u64 actual_end = min(end + 1, isize);
> > > -	u64 inline_len = actual_end - start;
> > > -	u64 aligned_end = ALIGN(end, fs_info->sectorsize);
> > > -	u64 data_len = inline_len;
> > > +	u64 data_len = compressed_size ? compressed_size : size;
> > >   	int ret;
> > >   	struct btrfs_path *path;
> > > 
> > > -	if (compressed_size)
> > > -		data_len = compressed_size;
> > > -
> > > -	if (start > 0 ||
> > > -	    actual_end > fs_info->sectorsize ||
> > > +	/*
> > > +	 * We can create an inline extent if it ends at or beyond the current
> > > +	 * i_size, is no larger than a sector (decompressed), and the (possibly
> > > +	 * compressed) data fits in a leaf and the configured maximum inline
> > > +	 * size.
> > > +	 */
> > 
> > Urgh, just some days ago Qu was talking about how awkward it is to have
> > mixed extents in a file. And now, AFAIU, you are making them more likely
> > since now they can be created not just at the beginning of the file but
> > also after i_size write. While this won't be a problem in and of itself
> > it goes just the opposite way of us trying to shrink the possible cases
> > when we can have mixed extents.
> 
> Tree-checker should reject such inline extent at non-zero offset.

This change does not allow creating inline extents at a non-zero offset.

> > Qu what is your take on that?
> 
> My question is, why encoded write needs to bother the inline extents at all?
> 
> My intuition of such encoded write is, it should not create inline
> extents at all.
> 
> Or is there any special use-case involved for encoded write?

We create compressed inline extents with normal writes. We should be
able to send and receive them without converting them into regular
extents.

Re: [PATCH v10 06/14] btrfs: optionally extend i_size in cow_file_range_inline()

[Qu Wenruo]

On 2021/8/21 上午2:11, Omar Sandoval wrote:
> On Fri, Aug 20, 2021 at 05:13:34PM +0800, Qu Wenruo wrote:
>>
>>
>> On 2021/8/20 下午4:51, Nikolay Borisov wrote:
>>>
>>>
>>> On 18.08.21 г. 0:06, Omar Sandoval wrote:
>>>> From: Omar Sandoval <osandov@fb.com>
>>>>
>>>> Currently, an inline extent is always created after i_size is extended
>>>> from btrfs_dirty_pages(). However, for encoded writes, we only want to
>>>> update i_size after we successfully created the inline extent.
>>
>> To me, the idea of write first then update isize is just going to cause
>> tons of inline extent related prblems.
>>
>> The current example is falloc, which only update the isize after the
>> falloc finishes.
>>
>> This behavior has already bothered me quite a lot, as it can easily
>> create mixed inline and regular extents.
>
> Do you have an example of how this would happen? I have the inode and
> extent bits locked during an encoded write, and I see that fallocate
> does the same.

xfs_io -f -c "pwrite 0 1K" -c "sync" -c "falloc 0 4k" -c "pwrite 4k 4k"

The [0, 1K) will be written as inline without doubt.

Then we go to falloc, it will try to zero the range [1K, 4K), but it
doesn't increase the isize.
Thus the page [0, 4k) will still be written back as inline, since isize
is still 1K.

Later [4K, 8K) will be written back as regular, causing mixed extents.

>
>> Can't we remember the old isize (with proper locking), enlarge isize
>> (with holes filled), do the write.
>>
>> If something wrong happened, we truncate the isize back to its old isize.
>>
[...]
>>>
>>> Urgh, just some days ago Qu was talking about how awkward it is to have
>>> mixed extents in a file. And now, AFAIU, you are making them more likely
>>> since now they can be created not just at the beginning of the file but
>>> also after i_size write. While this won't be a problem in and of itself
>>> it goes just the opposite way of us trying to shrink the possible cases
>>> when we can have mixed extents.
>>
>> Tree-checker should reject such inline extent at non-zero offset.
>
> This change does not allow creating inline extents at a non-zero offset.
>
>>> Qu what is your take on that?
>>
>> My question is, why encoded write needs to bother the inline extents at all?
>>
>> My intuition of such encoded write is, it should not create inline
>> extents at all.
>>
>> Or is there any special use-case involved for encoded write?
>
> We create compressed inline extents with normal writes. We should be
> able to send and receive them without converting them into regular
> extents.
>
But my first impression for any encoded write is that, they should work
like DIO, thus everything should be sectorsize aligned.

Then why could they create inline extent? As inline extent can only be
possible when the isize is smaller than sectorsize.

Thanks,
Qu

Re: [PATCH v10 06/14] btrfs: optionally extend i_size in cow_file_range_inline()

[Omar Sandoval]

On Sat, Aug 21, 2021 at 09:11:26AM +0800, Qu Wenruo wrote:
> 
> 
> On 2021/8/21 上午2:11, Omar Sandoval wrote:
> > On Fri, Aug 20, 2021 at 05:13:34PM +0800, Qu Wenruo wrote:
> > > 
> > > 
> > > On 2021/8/20 下午4:51, Nikolay Borisov wrote:
> > > > 
> > > > 
> > > > On 18.08.21 г. 0:06, Omar Sandoval wrote:
> > > > > From: Omar Sandoval <osandov@fb.com>
> > > > > 
> > > > > Currently, an inline extent is always created after i_size is extended
> > > > > from btrfs_dirty_pages(). However, for encoded writes, we only want to
> > > > > update i_size after we successfully created the inline extent.
> > > 
> > > To me, the idea of write first then update isize is just going to cause
> > > tons of inline extent related prblems.
> > > 
> > > The current example is falloc, which only update the isize after the
> > > falloc finishes.
> > > 
> > > This behavior has already bothered me quite a lot, as it can easily
> > > create mixed inline and regular extents.
> > 
> > Do you have an example of how this would happen? I have the inode and
> > extent bits locked during an encoded write, and I see that fallocate
> > does the same.
> 
> xfs_io -f -c "pwrite 0 1K" -c "sync" -c "falloc 0 4k" -c "pwrite 4k 4k"
> 
> The [0, 1K) will be written as inline without doubt.
> 
> Then we go to falloc, it will try to zero the range [1K, 4K), but it
> doesn't increase the isize.
> Thus the page [0, 4k) will still be written back as inline, since isize
> is still 1K.
> 
> Later [4K, 8K) will be written back as regular, causing mixed extents.

I'll have to read fallocate more closely to follow what's going on here
and figure out if it applies to encoded writes. Please help me out if
you see how this would be an issue with encoded writes.

> > > Can't we remember the old isize (with proper locking), enlarge isize
> > > (with holes filled), do the write.
> > > 
> > > If something wrong happened, we truncate the isize back to its old isize.
> > > 
> [...]
> > > > 
> > > > Urgh, just some days ago Qu was talking about how awkward it is to have
> > > > mixed extents in a file. And now, AFAIU, you are making them more likely
> > > > since now they can be created not just at the beginning of the file but
> > > > also after i_size write. While this won't be a problem in and of itself
> > > > it goes just the opposite way of us trying to shrink the possible cases
> > > > when we can have mixed extents.
> > > 
> > > Tree-checker should reject such inline extent at non-zero offset.
> > 
> > This change does not allow creating inline extents at a non-zero offset.
> > 
> > > > Qu what is your take on that?
> > > 
> > > My question is, why encoded write needs to bother the inline extents at all?
> > > 
> > > My intuition of such encoded write is, it should not create inline
> > > extents at all.
> > > 
> > > Or is there any special use-case involved for encoded write?
> > 
> > We create compressed inline extents with normal writes. We should be
> > able to send and receive them without converting them into regular
> > extents.
> > 
> But my first impression for any encoded write is that, they should work
> like DIO, thus everything should be sectorsize aligned.
> 
> Then why could they create inline extent? As inline extent can only be
> possible when the isize is smaller than sectorsize.

ENCODED_WRITE is not defined as "O_DIRECT, but encoded". It happens to
have some resemblance to O_DIRECT because we have alignment requirements
for new extents and because we bypass the page cache, but there's no
reason to copy arbitrary restrictions from O_DIRECT. If someone is using
ENCODED_WRITE to write compressed data, then they care about space
efficiency, so we should make efficient use of inline extents.

Re: [PATCH v10 06/14] btrfs: optionally extend i_size in cow_file_range_inline()

[Qu Wenruo]

On 2021/8/24 上午2:16, Omar Sandoval wrote:
> On Sat, Aug 21, 2021 at 09:11:26AM +0800, Qu Wenruo wrote:
>>
>>
>> On 2021/8/21 上午2:11, Omar Sandoval wrote:
>>> On Fri, Aug 20, 2021 at 05:13:34PM +0800, Qu Wenruo wrote:
>>>>
>>>>
>>>> On 2021/8/20 下午4:51, Nikolay Borisov wrote:
>>>>>
>>>>>
>>>>> On 18.08.21 г. 0:06, Omar Sandoval wrote:
>>>>>> From: Omar Sandoval <osandov@fb.com>
>>>>>>
>>>>>> Currently, an inline extent is always created after i_size is extended
>>>>>> from btrfs_dirty_pages(). However, for encoded writes, we only want to
>>>>>> update i_size after we successfully created the inline extent.
>>>>
>>>> To me, the idea of write first then update isize is just going to cause
>>>> tons of inline extent related prblems.
>>>>
>>>> The current example is falloc, which only update the isize after the
>>>> falloc finishes.
>>>>
>>>> This behavior has already bothered me quite a lot, as it can easily
>>>> create mixed inline and regular extents.
>>>
>>> Do you have an example of how this would happen? I have the inode and
>>> extent bits locked during an encoded write, and I see that fallocate
>>> does the same.
>>
>> xfs_io -f -c "pwrite 0 1K" -c "sync" -c "falloc 0 4k" -c "pwrite 4k 4k"
>>
>> The [0, 1K) will be written as inline without doubt.
>>
>> Then we go to falloc, it will try to zero the range [1K, 4K), but it
>> doesn't increase the isize.
>> Thus the page [0, 4k) will still be written back as inline, since isize
>> is still 1K.
>>
>> Later [4K, 8K) will be written back as regular, causing mixed extents.
>
> I'll have to read fallocate more closely to follow what's going on here
> and figure out if it applies to encoded writes. Please help me out if
> you see how this would be an issue with encoded writes.

This won't cause anything wrong, if the encoded writes follows the
existing inline extents requirement (always at offset 0).

Otherwise, the read path could be affected to handle inlined extent at
non-zero offset.

>
>>>> Can't we remember the old isize (with proper locking), enlarge isize
>>>> (with holes filled), do the write.
>>>>
>>>> If something wrong happened, we truncate the isize back to its old isize.
>>>>
>> [...]
>>>>>
>>>>> Urgh, just some days ago Qu was talking about how awkward it is to have
>>>>> mixed extents in a file. And now, AFAIU, you are making them more likely
>>>>> since now they can be created not just at the beginning of the file but
>>>>> also after i_size write. While this won't be a problem in and of itself
>>>>> it goes just the opposite way of us trying to shrink the possible cases
>>>>> when we can have mixed extents.
>>>>
>>>> Tree-checker should reject such inline extent at non-zero offset.
>>>
>>> This change does not allow creating inline extents at a non-zero offset.
>>>
>>>>> Qu what is your take on that?
>>>>
>>>> My question is, why encoded write needs to bother the inline extents at all?
>>>>
>>>> My intuition of such encoded write is, it should not create inline
>>>> extents at all.
>>>>
>>>> Or is there any special use-case involved for encoded write?
>>>
>>> We create compressed inline extents with normal writes. We should be
>>> able to send and receive them without converting them into regular
>>> extents.
>>>
>> But my first impression for any encoded write is that, they should work
>> like DIO, thus everything should be sectorsize aligned.
>>
>> Then why could they create inline extent? As inline extent can only be
>> possible when the isize is smaller than sectorsize.
>
> ENCODED_WRITE is not defined as "O_DIRECT, but encoded". It happens to
> have some resemblance to O_DIRECT because we have alignment requirements
> for new extents and because we bypass the page cache, but there's no
> reason to copy arbitrary restrictions from O_DIRECT. If someone is using
> ENCODED_WRITE to write compressed data, then they care about space
> efficiency, so we should make efficient use of inline extents.
>
Then as long as the inline extent requirement for 0 offset is still
followed, I'll be fine with that.

But for non-zero offset inline extent? It looks like a much larger
change, and may affect read path.

So I'd prefer we keep the 0 offset requirement for inline extent, and
find a better way to work around.

Thanks,
Qu

Re: [PATCH v10 06/14] btrfs: optionally extend i_size in cow_file_range_inline()

[Omar Sandoval]

On Tue, Aug 24, 2021 at 07:32:06AM +0800, Qu Wenruo wrote:
> 
> 
> On 2021/8/24 上午2:16, Omar Sandoval wrote:
> > On Sat, Aug 21, 2021 at 09:11:26AM +0800, Qu Wenruo wrote:
> > > 
> > > 
> > > On 2021/8/21 上午2:11, Omar Sandoval wrote:
> > > > On Fri, Aug 20, 2021 at 05:13:34PM +0800, Qu Wenruo wrote:
> > > > > 
> > > > > 
> > > > > On 2021/8/20 下午4:51, Nikolay Borisov wrote:
> > > > > > 
> > > > > > 
> > > > > > On 18.08.21 г. 0:06, Omar Sandoval wrote:
> > > > > > > From: Omar Sandoval <osandov@fb.com>
> > > > > > > 
> > > > > > > Currently, an inline extent is always created after i_size is extended
> > > > > > > from btrfs_dirty_pages(). However, for encoded writes, we only want to
> > > > > > > update i_size after we successfully created the inline extent.
> > > > > 
> > > > > To me, the idea of write first then update isize is just going to cause
> > > > > tons of inline extent related prblems.
> > > > > 
> > > > > The current example is falloc, which only update the isize after the
> > > > > falloc finishes.
> > > > > 
> > > > > This behavior has already bothered me quite a lot, as it can easily
> > > > > create mixed inline and regular extents.
> > > > 
> > > > Do you have an example of how this would happen? I have the inode and
> > > > extent bits locked during an encoded write, and I see that fallocate
> > > > does the same.
> > > 
> > > xfs_io -f -c "pwrite 0 1K" -c "sync" -c "falloc 0 4k" -c "pwrite 4k 4k"
> > > 
> > > The [0, 1K) will be written as inline without doubt.
> > > 
> > > Then we go to falloc, it will try to zero the range [1K, 4K), but it
> > > doesn't increase the isize.
> > > Thus the page [0, 4k) will still be written back as inline, since isize
> > > is still 1K.
> > > 
> > > Later [4K, 8K) will be written back as regular, causing mixed extents.
> > 
> > I'll have to read fallocate more closely to follow what's going on here
> > and figure out if it applies to encoded writes. Please help me out if
> > you see how this would be an issue with encoded writes.
> 
> This won't cause anything wrong, if the encoded writes follows the
> existing inline extents requirement (always at offset 0).
> 
> Otherwise, the read path could be affected to handle inlined extent at
> non-zero offset.
> 
> > 
> > > > > Can't we remember the old isize (with proper locking), enlarge isize
> > > > > (with holes filled), do the write.
> > > > > 
> > > > > If something wrong happened, we truncate the isize back to its old isize.
> > > > > 
> > > [...]
> > > > > > 
> > > > > > Urgh, just some days ago Qu was talking about how awkward it is to have
> > > > > > mixed extents in a file. And now, AFAIU, you are making them more likely
> > > > > > since now they can be created not just at the beginning of the file but
> > > > > > also after i_size write. While this won't be a problem in and of itself
> > > > > > it goes just the opposite way of us trying to shrink the possible cases
> > > > > > when we can have mixed extents.
> > > > > 
> > > > > Tree-checker should reject such inline extent at non-zero offset.
> > > > 
> > > > This change does not allow creating inline extents at a non-zero offset.
> > > > 
> > > > > > Qu what is your take on that?
> > > > > 
> > > > > My question is, why encoded write needs to bother the inline extents at all?
> > > > > 
> > > > > My intuition of such encoded write is, it should not create inline
> > > > > extents at all.
> > > > > 
> > > > > Or is there any special use-case involved for encoded write?
> > > > 
> > > > We create compressed inline extents with normal writes. We should be
> > > > able to send and receive them without converting them into regular
> > > > extents.
> > > > 
> > > But my first impression for any encoded write is that, they should work
> > > like DIO, thus everything should be sectorsize aligned.
> > > 
> > > Then why could they create inline extent? As inline extent can only be
> > > possible when the isize is smaller than sectorsize.
> > 
> > ENCODED_WRITE is not defined as "O_DIRECT, but encoded". It happens to
> > have some resemblance to O_DIRECT because we have alignment requirements
> > for new extents and because we bypass the page cache, but there's no
> > reason to copy arbitrary restrictions from O_DIRECT. If someone is using
> > ENCODED_WRITE to write compressed data, then they care about space
> > efficiency, so we should make efficient use of inline extents.
> > 
> Then as long as the inline extent requirement for 0 offset is still
> followed, I'll be fine with that.
> 
> But for non-zero offset inline extent? It looks like a much larger
> change, and may affect read path.
> 
> So I'd prefer we keep the 0 offset requirement for inline extent, and
> find a better way to work around.

Ah, okay. I didn't get rid of the 0 offset requirement and I have no
plans to. In fact, this patch kind of does the opposite: it gets rid of
the start parameter to cow_file_range_inline() because it doesn't make
sense for it to ever be anything other than 0 (and we're already
checking that start == 0 in the callers).