[PATCH V12 06/14] xfs: Check for extent overflow when writing to unwritten extent
From: Chandan Babu R <hidden>
Date: 2021-01-04 10:33:02
Subsystem:
filesystems (vfs and infrastructure), the rest, xfs filesystem · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds, Carlos Maiolino
A write to a sub-interval of an existing unwritten extent causes the original extent to be split into 3 extents i.e. | Unwritten | Real | Unwritten | Hence extent count can increase by 2. Reviewed-by: Darrick J. Wong <redacted> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Allison Henderson <redacted> Signed-off-by: Chandan Babu R <redacted> --- fs/xfs/libxfs/xfs_inode_fork.h | 9 +++++++++ fs/xfs/xfs_iomap.c | 5 +++++ 2 files changed, 14 insertions(+)
diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
index 8d89838e23f8..917e289ad962 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.h
+++ b/fs/xfs/libxfs/xfs_inode_fork.h@@ -70,6 +70,15 @@ struct xfs_ifork { #define XFS_IEXT_ATTR_MANIP_CNT(rmt_blks) \ (XFS_DA_NODE_MAXDEPTH + max(1, rmt_blks)) +/* + * A write to a sub-interval of an existing unwritten extent causes the original + * extent to be split into 3 extents + * i.e. | Unwritten | Real | Unwritten | + * Hence extent count can increase by 2. + */ +#define XFS_IEXT_WRITE_UNWRITTEN_CNT (2) + + /* * Fork handling. */
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index f53690febb22..5bf84622421d 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c@@ -566,6 +566,11 @@ xfs_iomap_write_unwritten( if (error) goto error_on_bmapi_transaction; + error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK, + XFS_IEXT_WRITE_UNWRITTEN_CNT); + if (error) + goto error_on_bmapi_transaction; + /* * Modify the unwritten extent state of the buffer. */
--
2.29.2