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From: Goldwyn Rodrigues <rgoldwyn@suse.de>
To: linux-fsdevel@vger.kernel.org
Cc: linux-btrfs@vger.kernel.org, hch@lst.de, darrick.wong@oracle.com,
	ruansy.fnst@cn.fujitsu.com, Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: [PATCH 01/13] iomap: Use a IOMAP_COW/srcmap for a read-modify-write I/O
Date: Fri,  2 Aug 2019 17:00:36 -0500	[thread overview]
Message-ID: <20190802220048.16142-2-rgoldwyn@suse.de> (raw)
In-Reply-To: <20190802220048.16142-1-rgoldwyn@suse.de>

From: Goldwyn Rodrigues <rgoldwyn@suse.com>

Introduces a new type IOMAP_COW, which means the data at offset
must be read from a srcmap and copied before performing the
write on the offset.

The srcmap is used to identify where the read is to be performed
from. This is passed to iomap->begin() of the respective
filesystem, which is supposed to put in the details for
reading before performing the copy for CoW.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
---
 fs/dax.c               |  8 +++++---
 fs/ext2/inode.c        |  2 +-
 fs/ext4/inode.c        |  2 +-
 fs/gfs2/bmap.c         |  3 ++-
 fs/iomap/apply.c       |  5 +++--
 fs/iomap/buffered-io.c | 14 +++++++-------
 fs/iomap/direct-io.c   |  2 +-
 fs/iomap/fiemap.c      |  4 ++--
 fs/iomap/seek.c        |  4 ++--
 fs/iomap/swapfile.c    |  3 ++-
 fs/xfs/xfs_iomap.c     |  9 ++++++---
 include/linux/iomap.h  |  6 ++++--
 12 files changed, 36 insertions(+), 26 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index a237141d8787..b21d9a9cde2b 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1090,7 +1090,7 @@ EXPORT_SYMBOL_GPL(__dax_zero_page_range);
 
 static loff_t
 dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
-		struct iomap *iomap)
+		struct iomap *iomap, struct iomap *srcmap)
 {
 	struct block_device *bdev = iomap->bdev;
 	struct dax_device *dax_dev = iomap->dax_dev;
@@ -1248,6 +1248,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
 	unsigned long vaddr = vmf->address;
 	loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT;
 	struct iomap iomap = { 0 };
+	struct iomap srcmap = { 0 };
 	unsigned flags = IOMAP_FAULT;
 	int error, major = 0;
 	bool write = vmf->flags & FAULT_FLAG_WRITE;
@@ -1292,7 +1293,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
 	 * the file system block size to be equal the page size, which means
 	 * that we never have to deal with more than a single extent here.
 	 */
-	error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap);
+	error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap, &srcmap);
 	if (iomap_errp)
 		*iomap_errp = error;
 	if (error) {
@@ -1472,6 +1473,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
 	struct inode *inode = mapping->host;
 	vm_fault_t result = VM_FAULT_FALLBACK;
 	struct iomap iomap = { 0 };
+	struct iomap srcmap = { 0 };
 	pgoff_t max_pgoff;
 	void *entry;
 	loff_t pos;
@@ -1546,7 +1548,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
 	 * to look up our filesystem block.
 	 */
 	pos = (loff_t)xas.xa_index << PAGE_SHIFT;
-	error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap);
+	error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap, &srcmap);
 	if (error)
 		goto unlock_entry;
 
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 7004ce581a32..467c13ff6b40 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -801,7 +801,7 @@ int ext2_get_block(struct inode *inode, sector_t iblock,
 
 #ifdef CONFIG_FS_DAX
 static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
-		unsigned flags, struct iomap *iomap)
+		unsigned flags, struct iomap *iomap, struct iomap *srcmap)
 {
 	unsigned int blkbits = inode->i_blkbits;
 	unsigned long first_block = offset >> blkbits;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 420fe3deed39..918f94eff799 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3453,7 +3453,7 @@ static bool ext4_inode_datasync_dirty(struct inode *inode)
 }
 
 static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
-			    unsigned flags, struct iomap *iomap)
+			    unsigned flags, struct iomap *iomap, struct iomap *srcmap)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 	unsigned int blkbits = inode->i_blkbits;
diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 79581b9bdebb..0bf8e8fa82bd 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -1123,7 +1123,8 @@ static int gfs2_iomap_begin_write(struct inode *inode, loff_t pos,
 }
 
 static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
-			    unsigned flags, struct iomap *iomap)
+			    unsigned flags, struct iomap *iomap,
+			    struct iomap *srcmap)
 {
 	struct gfs2_inode *ip = GFS2_I(inode);
 	struct metapath mp = { .mp_aheight = 1, };
diff --git a/fs/iomap/apply.c b/fs/iomap/apply.c
index 54c02aecf3cd..6cdb362fff36 100644
--- a/fs/iomap/apply.c
+++ b/fs/iomap/apply.c
@@ -24,6 +24,7 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
 		const struct iomap_ops *ops, void *data, iomap_actor_t actor)
 {
 	struct iomap iomap = { 0 };
+	struct iomap srcmap = { 0 };
 	loff_t written = 0, ret;
 
 	/*
@@ -38,7 +39,7 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
 	 * expose transient stale data. If the reserve fails, we can safely
 	 * back out at this point as there is nothing to undo.
 	 */
-	ret = ops->iomap_begin(inode, pos, length, flags, &iomap);
+	ret = ops->iomap_begin(inode, pos, length, flags, &iomap, &srcmap);
 	if (ret)
 		return ret;
 	if (WARN_ON(iomap.offset > pos))
@@ -58,7 +59,7 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
 	 * we can do the copy-in page by page without having to worry about
 	 * failures exposing transient data.
 	 */
-	written = actor(inode, pos, length, data, &iomap);
+	written = actor(inode, pos, length, data, &iomap, &srcmap);
 
 	/*
 	 * Now the data has been copied, commit the range we've copied.  This
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index e25901ae3ff4..f27756c0b31c 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -205,7 +205,7 @@ iomap_read_inline_data(struct inode *inode, struct page *page,
 
 static loff_t
 iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
-		struct iomap *iomap)
+		struct iomap *iomap, struct iomap *srcmap)
 {
 	struct iomap_readpage_ctx *ctx = data;
 	struct page *page = ctx->cur_page;
@@ -351,7 +351,7 @@ iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos,
 
 static loff_t
 iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length,
-		void *data, struct iomap *iomap)
+		void *data, struct iomap *iomap, struct iomap *srcmap)
 {
 	struct iomap_readpage_ctx *ctx = data;
 	loff_t done, ret;
@@ -371,7 +371,7 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length,
 			ctx->cur_page_in_bio = false;
 		}
 		ret = iomap_readpage_actor(inode, pos + done, length - done,
-				ctx, iomap);
+				ctx, iomap, srcmap);
 	}
 
 	return done;
@@ -736,7 +736,7 @@ iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
 
 static loff_t
 iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
-		struct iomap *iomap)
+		struct iomap *iomap, struct iomap *srcmap)
 {
 	struct iov_iter *i = data;
 	long status = 0;
@@ -853,7 +853,7 @@ __iomap_read_page(struct inode *inode, loff_t offset)
 
 static loff_t
 iomap_dirty_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
-		struct iomap *iomap)
+		struct iomap *iomap, struct iomap *srcmap)
 {
 	long status = 0;
 	ssize_t written = 0;
@@ -942,7 +942,7 @@ static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes,
 
 static loff_t
 iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count,
-		void *data, struct iomap *iomap)
+		void *data, struct iomap *iomap, struct iomap *srcmap)
 {
 	bool *did_zero = data;
 	loff_t written = 0;
@@ -1011,7 +1011,7 @@ EXPORT_SYMBOL_GPL(iomap_truncate_page);
 
 static loff_t
 iomap_page_mkwrite_actor(struct inode *inode, loff_t pos, loff_t length,
-		void *data, struct iomap *iomap)
+		void *data, struct iomap *iomap, struct iomap *srcmap)
 {
 	struct page *page = data;
 	int ret;
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 10517cea9682..5279029c7a3c 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -362,7 +362,7 @@ iomap_dio_inline_actor(struct inode *inode, loff_t pos, loff_t length,
 
 static loff_t
 iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length,
-		void *data, struct iomap *iomap)
+		void *data, struct iomap *iomap, struct iomap *srcmap)
 {
 	struct iomap_dio *dio = data;
 
diff --git a/fs/iomap/fiemap.c b/fs/iomap/fiemap.c
index f26fdd36e383..690ef2d7c6c8 100644
--- a/fs/iomap/fiemap.c
+++ b/fs/iomap/fiemap.c
@@ -44,7 +44,7 @@ static int iomap_to_fiemap(struct fiemap_extent_info *fi,
 
 static loff_t
 iomap_fiemap_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
-		struct iomap *iomap)
+		struct iomap *iomap, struct iomap *srcmap)
 {
 	struct fiemap_ctx *ctx = data;
 	loff_t ret = length;
@@ -111,7 +111,7 @@ EXPORT_SYMBOL_GPL(iomap_fiemap);
 
 static loff_t
 iomap_bmap_actor(struct inode *inode, loff_t pos, loff_t length,
-		void *data, struct iomap *iomap)
+		void *data, struct iomap *iomap, struct iomap *srcmap)
 {
 	sector_t *bno = data, addr;
 
diff --git a/fs/iomap/seek.c b/fs/iomap/seek.c
index c04bad4b2b43..89f61d93c0bc 100644
--- a/fs/iomap/seek.c
+++ b/fs/iomap/seek.c
@@ -119,7 +119,7 @@ page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length,
 
 static loff_t
 iomap_seek_hole_actor(struct inode *inode, loff_t offset, loff_t length,
-		      void *data, struct iomap *iomap)
+		      void *data, struct iomap *iomap, struct iomap *srcmap)
 {
 	switch (iomap->type) {
 	case IOMAP_UNWRITTEN:
@@ -165,7 +165,7 @@ EXPORT_SYMBOL_GPL(iomap_seek_hole);
 
 static loff_t
 iomap_seek_data_actor(struct inode *inode, loff_t offset, loff_t length,
-		      void *data, struct iomap *iomap)
+		      void *data, struct iomap *iomap, struct iomap *srcmap)
 {
 	switch (iomap->type) {
 	case IOMAP_HOLE:
diff --git a/fs/iomap/swapfile.c b/fs/iomap/swapfile.c
index 152a230f668d..a648dbf6991e 100644
--- a/fs/iomap/swapfile.c
+++ b/fs/iomap/swapfile.c
@@ -76,7 +76,8 @@ static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi)
  * distinction between written and unwritten extents.
  */
 static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos,
-		loff_t count, void *data, struct iomap *iomap)
+		loff_t count, void *data, struct iomap *iomap,
+		struct iomap *srcmap)
 {
 	struct iomap_swapfile_info *isi = data;
 	int error;
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 3a4310d7cb59..8321733c16c3 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -922,7 +922,8 @@ xfs_file_iomap_begin(
 	loff_t			offset,
 	loff_t			length,
 	unsigned		flags,
-	struct iomap		*iomap)
+	struct iomap		*iomap,
+	struct iomap		*srcmap)
 {
 	struct xfs_inode	*ip = XFS_I(inode);
 	struct xfs_mount	*mp = ip->i_mount;
@@ -1145,7 +1146,8 @@ xfs_seek_iomap_begin(
 	loff_t			offset,
 	loff_t			length,
 	unsigned		flags,
-	struct iomap		*iomap)
+	struct iomap		*iomap,
+	struct iomap		*srcmap)
 {
 	struct xfs_inode	*ip = XFS_I(inode);
 	struct xfs_mount	*mp = ip->i_mount;
@@ -1231,7 +1233,8 @@ xfs_xattr_iomap_begin(
 	loff_t			offset,
 	loff_t			length,
 	unsigned		flags,
-	struct iomap		*iomap)
+	struct iomap		*iomap,
+	struct iomap		*srcmap)
 {
 	struct xfs_inode	*ip = XFS_I(inode);
 	struct xfs_mount	*mp = ip->i_mount;
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index bc499ceae392..5b2055e8ca8a 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -26,6 +26,7 @@ struct vm_fault;
 #define IOMAP_MAPPED	0x03	/* blocks allocated at @addr */
 #define IOMAP_UNWRITTEN	0x04	/* blocks allocated at @addr in unwritten state */
 #define IOMAP_INLINE	0x05	/* data inline in the inode */
+#define IOMAP_COW	0x06	/* copy data from srcmap before writing */
 
 /*
  * Flags for all iomap mappings:
@@ -110,7 +111,8 @@ struct iomap_ops {
 	 * The actual length is returned in iomap->length.
 	 */
 	int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
-			unsigned flags, struct iomap *iomap);
+			unsigned flags, struct iomap *iomap,
+			struct iomap *srcmap);
 
 	/*
 	 * Commit and/or unreserve space previous allocated using iomap_begin.
@@ -126,7 +128,7 @@ struct iomap_ops {
  * Main iomap iterator function.
  */
 typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len,
-		void *data, struct iomap *iomap);
+		void *data, struct iomap *iomap, struct iomap *srcmap);
 
 loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length,
 		unsigned flags, const struct iomap_ops *ops, void *data,
-- 
2.16.4


  reply	other threads:[~2019-08-02 22:00 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-02 22:00 [PATCH v2 0/13] Btrfs iomap Goldwyn Rodrigues
2019-08-02 22:00 ` Goldwyn Rodrigues [this message]
2019-08-03  0:39   ` [PATCH 01/13] iomap: Use a IOMAP_COW/srcmap for a read-modify-write I/O Darrick J. Wong
2019-08-05  0:06   ` Dave Chinner
2019-08-02 22:00 ` [PATCH 02/13] iomap: Read page from srcmap for IOMAP_COW Goldwyn Rodrigues
2019-08-03  0:23   ` Darrick J. Wong
2019-08-04 23:52   ` Dave Chinner
2019-08-02 22:00 ` [PATCH 03/13] btrfs: Eliminate PagePrivate for btrfs data pages Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 04/13] btrfs: Add a simple buffered iomap write Goldwyn Rodrigues
2019-08-05  0:11   ` Dave Chinner
2019-08-22 15:05     ` Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 05/13] btrfs: Add CoW in iomap based writes Goldwyn Rodrigues
2019-08-05  0:13   ` Dave Chinner
2019-08-22 15:01     ` Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 06/13] btrfs: remove buffered write code made unnecessary Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 07/13] btrfs: basic direct read operation Goldwyn Rodrigues
2019-08-12 12:32   ` RITESH HARJANI
2019-08-22 15:00     ` Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 08/13] btrfs: Carve out btrfs_get_extent_map_write() out of btrfs_get_blocks_write() Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 09/13] btrfs: Rename __endio_write_update_ordered() to btrfs_update_ordered_extent() Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 10/13] iomap: use a function pointer for dio submits Goldwyn Rodrigues
2019-08-03  0:21   ` Darrick J. Wong
2019-08-05 16:08     ` Goldwyn Rodrigues
2019-08-04 23:43   ` Dave Chinner
2019-08-05 16:08     ` Goldwyn Rodrigues
2019-08-05 21:54       ` Dave Chinner
2019-08-08  4:26         ` Gao Xiang
2019-08-08  4:26           ` Gao Xiang
2019-08-08  4:52           ` Gao Xiang
2019-08-08  4:52             ` Gao Xiang
2019-08-08  5:49           ` Eric Biggers
2019-08-08  5:49             ` Eric Biggers
2019-08-08  6:28             ` Gao Xiang
2019-08-08  6:28               ` Gao Xiang
2019-08-08  8:16             ` Dave Chinner
2019-08-08  8:16               ` Dave Chinner
2019-08-08  8:57               ` Gao Xiang
2019-08-08  8:57                 ` Gao Xiang
2019-08-08  9:29               ` Gao Xiang
2019-08-08  9:29                 ` Gao Xiang
2019-08-08 11:21                 ` Gao Xiang
2019-08-08 11:21                   ` Gao Xiang
2019-08-08 13:11                   ` Gao Xiang
2019-08-08 13:11                     ` Gao Xiang
2019-08-09 20:45             ` Matthew Wilcox
2019-08-09 20:45               ` Matthew Wilcox
2019-08-09 23:45               ` Gao Xiang
2019-08-09 23:45                 ` Gao Xiang
2019-08-10  0:31                 ` Eric Biggers
2019-08-10  0:31                   ` Eric Biggers
2019-08-10  0:50                   ` Eric Biggers
2019-08-10  0:50                     ` Eric Biggers
2019-08-10  1:34                     ` Gao Xiang
2019-08-10  1:34                       ` Gao Xiang
2019-08-10  1:13                   ` Gao Xiang
2019-08-10  1:13                     ` Gao Xiang
2019-08-10  0:17               ` Eric Biggers
2019-08-10  0:17                 ` Eric Biggers
2019-08-02 22:00 ` [PATCH 11/13] btrfs: Use iomap_dio_rw for performing direct I/O writes Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 12/13] btrfs: Remove btrfs_dio_data and __btrfs_direct_write Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 13/13] btrfs: update inode size during bio completion Goldwyn Rodrigues

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