From: Goldwyn Rodrigues <rgoldwyn@suse.de>
To: linux-btrfs@vger.kernel.org
Cc: Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: [PATCH 02/10] btrfs: basic dax read
Date: Wed, 5 Dec 2018 06:28:27 -0600 [thread overview]
Message-ID: <20181205122835.19290-3-rgoldwyn@suse.de> (raw)
In-Reply-To: <20181205122835.19290-1-rgoldwyn@suse.de>
From: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
---
fs/btrfs/Makefile | 1 +
fs/btrfs/ctree.h | 5 ++++
fs/btrfs/dax.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/btrfs/file.c | 13 ++++++++++-
4 files changed, 86 insertions(+), 1 deletion(-)
create mode 100644 fs/btrfs/dax.c
diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index ca693dd554e9..1fa77b875ae9 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -12,6 +12,7 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
reada.o backref.o ulist.o qgroup.o send.o dev-replace.o raid56.o \
uuid-tree.o props.o free-space-tree.o tree-checker.o
+btrfs-$(CONFIG_FS_DAX) += dax.o
btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o
btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o
btrfs-$(CONFIG_BTRFS_FS_REF_VERIFY) += ref-verify.o
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 5cc470fa6a40..038d64ecebe5 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3685,6 +3685,11 @@ int btrfs_reada_wait(void *handle);
void btrfs_reada_detach(void *handle);
int btree_readahead_hook(struct extent_buffer *eb, int err);
+#ifdef CONFIG_FS_DAX
+/* dax.c */
+ssize_t btrfs_file_dax_read(struct kiocb *iocb, struct iov_iter *to);
+#endif /* CONFIG_FS_DAX */
+
static inline int is_fstree(u64 rootid)
{
if (rootid == BTRFS_FS_TREE_OBJECTID ||
diff --git a/fs/btrfs/dax.c b/fs/btrfs/dax.c
new file mode 100644
index 000000000000..d614bf73bf8e
--- /dev/null
+++ b/fs/btrfs/dax.c
@@ -0,0 +1,68 @@
+#include <linux/dax.h>
+#include <linux/uio.h>
+#include "ctree.h"
+#include "btrfs_inode.h"
+
+static ssize_t em_dax_rw(struct inode *inode, struct extent_map *em, u64 pos,
+ u64 len, struct iov_iter *iter)
+{
+ struct dax_device *dax_dev = fs_dax_get_by_bdev(em->bdev);
+ ssize_t map_len;
+ pgoff_t blk_pg;
+ void *kaddr;
+ sector_t blk_start;
+ unsigned offset = pos & (PAGE_SIZE - 1);
+
+ len = min(len + offset, em->len - (pos - em->start));
+ len = ALIGN(len, PAGE_SIZE);
+ blk_start = (get_start_sect(em->bdev) << 9) + (em->block_start + (pos - em->start));
+ blk_pg = blk_start - offset;
+ map_len = dax_direct_access(dax_dev, PHYS_PFN(blk_pg), PHYS_PFN(len), &kaddr, NULL);
+ map_len = PFN_PHYS(map_len);
+ kaddr += offset;
+ map_len -= offset;
+ if (map_len > len)
+ map_len = len;
+ if (iov_iter_rw(iter) == WRITE)
+ return dax_copy_from_iter(dax_dev, blk_pg, kaddr, map_len, iter);
+ else
+ return dax_copy_to_iter(dax_dev, blk_pg, kaddr, map_len, iter);
+}
+
+ssize_t btrfs_file_dax_read(struct kiocb *iocb, struct iov_iter *to)
+{
+ size_t ret = 0, done = 0, count = iov_iter_count(to);
+ struct extent_map *em;
+ u64 pos = iocb->ki_pos;
+ u64 end = pos + count;
+ struct inode *inode = file_inode(iocb->ki_filp);
+
+ if (!count)
+ return 0;
+
+ end = i_size_read(inode) < end ? i_size_read(inode) : end;
+
+ while (pos < end) {
+ u64 len = end - pos;
+
+ em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, pos, len, 0);
+ if (IS_ERR(em)) {
+ if (!ret)
+ ret = PTR_ERR(em);
+ goto out;
+ }
+
+ BUG_ON(em->flags & EXTENT_FLAG_FS_MAPPING);
+
+ ret = em_dax_rw(inode, em, pos, len, to);
+ if (ret < 0)
+ goto out;
+ pos += ret;
+ done += ret;
+ }
+
+out:
+ iocb->ki_pos += done;
+ return done ? done : ret;
+}
+
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 58e93bce3036..ef6ed93f44d1 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -3308,9 +3308,20 @@ static int btrfs_file_open(struct inode *inode, struct file *filp)
return generic_file_open(inode, filp);
}
+static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+
+#ifdef CONFIG_FS_DAX
+ if (IS_DAX(inode))
+ return btrfs_file_dax_read(iocb, to);
+#endif
+ return generic_file_read_iter(iocb, to);
+}
+
const struct file_operations btrfs_file_operations = {
.llseek = btrfs_file_llseek,
- .read_iter = generic_file_read_iter,
+ .read_iter = btrfs_file_read_iter,
.splice_read = generic_file_splice_read,
.write_iter = btrfs_file_write_iter,
.mmap = btrfs_file_mmap,
--
2.16.4
next prev parent reply other threads:[~2018-12-05 12:28 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-05 12:28 [PATCH 00/10] btrfs: Support for DAX devices Goldwyn Rodrigues
2018-12-05 12:28 ` [PATCH 01/10] btrfs: create a mount option for dax Goldwyn Rodrigues
2018-12-05 12:42 ` Johannes Thumshirn
2018-12-05 12:43 ` Nikolay Borisov
2018-12-05 14:59 ` Adam Borowski
2018-12-05 12:28 ` Goldwyn Rodrigues [this message]
2018-12-05 13:11 ` [PATCH 02/10] btrfs: basic dax read Nikolay Borisov
2018-12-05 13:22 ` Johannes Thumshirn
2018-12-05 12:28 ` [PATCH 03/10] btrfs: dax: read zeros from holes Goldwyn Rodrigues
2018-12-05 13:26 ` Nikolay Borisov
2018-12-05 12:28 ` [PATCH 04/10] Rename __endio_write_update_ordered() to btrfs_update_ordered_extent() Goldwyn Rodrigues
2018-12-05 13:35 ` Nikolay Borisov
2018-12-05 12:28 ` [PATCH 05/10] btrfs: Carve out btrfs_get_extent_map_write() out of btrfs_get_blocks_write() Goldwyn Rodrigues
2018-12-05 12:28 ` [PATCH 06/10] btrfs: dax write support Goldwyn Rodrigues
2018-12-05 13:56 ` Johannes Thumshirn
2018-12-05 12:28 ` [PATCH 07/10] dax: export functions for use with btrfs Goldwyn Rodrigues
2018-12-05 13:59 ` Johannes Thumshirn
2018-12-05 14:52 ` Christoph Hellwig
2018-12-06 11:46 ` Goldwyn Rodrigues
2018-12-12 8:07 ` Christoph Hellwig
2019-03-26 19:36 ` Dan Williams
2019-03-27 11:10 ` Goldwyn Rodrigues
2018-12-05 12:28 ` [PATCH 08/10] btrfs: dax add read mmap path Goldwyn Rodrigues
2018-12-05 12:28 ` [PATCH 09/10] btrfs: dax support for cow_page/mmap_private and shared Goldwyn Rodrigues
2018-12-05 12:28 ` [PATCH 10/10] btrfs: dax mmap write Goldwyn Rodrigues
2018-12-05 13:03 ` [PATCH 00/10] btrfs: Support for DAX devices Qu Wenruo
2018-12-05 21:36 ` Jeff Mahoney
2018-12-05 13:57 ` Adam Borowski
2018-12-05 21:37 ` Jeff Mahoney
2018-12-06 7:40 ` Robert White
2018-12-06 10:07 ` Johannes Thumshirn
2018-12-06 11:47 ` Goldwyn Rodrigues
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