[PATCH V12 08/14] xfs: Check for extent overflow when remapping an extent
From: Chandan Babu R <hidden>
Date: 2021-01-04 10:33:04
Subsystem:
filesystems (vfs and infrastructure), the rest, xfs filesystem · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds, Carlos Maiolino
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 <redacted> Reviewed-by: Darrick J. Wong <redacted> Signed-off-by: Chandan Babu R <redacted> --- 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 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
--
2.29.2