From: Chandan Babu R Date: Sat, 23 Jan 2021 00:48:14 +0000 (-0800) Subject: xfs: Check for extent overflow when moving extent from cow to data fork X-Git-Tag: io_uring-worker.v3-2021-02-25~57^2~75 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=5f1d5bbfb2e674052a9fe542f53678978af20770;p=linux-block.git xfs: Check for extent overflow when moving extent from cow to data fork Moving an extent to data fork can cause a sub-interval of an existing extent to be unmapped. This will increase extent count by 1. Mapping in the new extent can increase the extent count by 1 again i.e. | Old extent | New extent | Old extent | Hence number of extents increases 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 --- diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h index 917e289ad962..c8f279edc5c1 100644 --- a/fs/xfs/libxfs/xfs_inode_fork.h +++ b/fs/xfs/libxfs/xfs_inode_fork.h @@ -79,6 +79,15 @@ struct xfs_ifork { #define XFS_IEXT_WRITE_UNWRITTEN_CNT (2) +/* + * Moving an extent to data fork can cause a sub-interval of an existing extent + * to be unmapped. This will increase extent count by 1. Mapping in the new + * extent can increase the extent count by 1 again i.e. + * | Old extent | New extent | Old extent | + * Hence number of extents increases by 2. + */ +#define XFS_IEXT_REFLINK_END_COW_CNT (2) + /* * Fork handling. */ diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index 6fa05fb78189..ca0ac1426d74 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -628,6 +628,11 @@ xfs_reflink_end_cow_extent( xfs_ilock(ip, XFS_ILOCK_EXCL); xfs_trans_ijoin(tp, ip, 0); + error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK, + XFS_IEXT_REFLINK_END_COW_CNT); + if (error) + goto out_cancel; + /* * In case of racing, overlapping AIO writes no COW extents might be * left by the time I/O completes for the loser of the race. In that