From: Chandan Babu R Date: Sat, 23 Jan 2021 00:48:14 +0000 (-0800) Subject: xfs: Check for extent overflow when remapping an extent X-Git-Tag: io_uring-worker.v3-2021-02-25~57^2~74 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=ee898d78c3540b44270a5fdffe208d7bbb219d93;p=linux-block.git xfs: Check for extent overflow when remapping an extent Remapping an extent involves unmapping the existing extent and mapping in the new extent. When unmapping, an extent containing the entire unmap range can be split into two extents, i.e. | Old extent | hole | Old extent | Hence extent count increases by 1. Mapping in the new extent into the destination file can increase the extent count by 1. Reviewed-by: Allison Henderson Reviewed-by: Darrick J. Wong Signed-off-by: Chandan Babu R Signed-off-by: Darrick J. Wong --- diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index ca0ac1426d74..e1c98dbf79e4 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -1006,6 +1006,7 @@ xfs_reflink_remap_extent( unsigned int resblks; bool smap_real; bool dmap_written = xfs_bmap_is_written_extent(dmap); + int iext_delta = 0; int nimaps; int error; @@ -1099,6 +1100,16 @@ xfs_reflink_remap_extent( goto out_cancel; } + if (smap_real) + ++iext_delta; + + if (dmap_written) + ++iext_delta; + + error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK, iext_delta); + if (error) + goto out_cancel; + if (smap_real) { /* * If the extent we're unmapping is backed by storage (written