From ee898d78c3540b44270a5fdffe208d7bbb219d93 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 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 --- fs/xfs/xfs_reflink.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index ca0ac14..e1c98db 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 -- 2.7.4