From c442f3086d5a108b7ff086c8ade1923a8f389db5 Mon Sep 17 00:00:00 2001 From: Chandan Babu R Date: Fri, 22 Jan 2021 16:48:14 -0800 Subject: [PATCH] xfs: Check for extent overflow when writing to unwritten extent 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 Reviewed-by: Christoph Hellwig Reviewed-by: Allison Henderson Signed-off-by: Chandan Babu R Signed-off-by: Darrick J. Wong --- 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 8d89838e23f80..917e289ad9623 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 32246d90b9cb6..8f4b27cded200 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. */ -- 2.30.2