[PATCH] xfs: reserve a full directory block when repair expands the tempdir

[Javier Tia]

xrep_dir_swap_prep() passes args.total = 1 to xfs_dir2_sf_to_block(),
but the conversion allocates args->geo->fsbcount filesystem blocks,
which is 1 << sb_dirblklog.  The two agree only when the directory
block size equals the filesystem block size, so the shortfall is
invisible on a 4k block filesystem and is four blocks on a 1k block
filesystem carrying a 4k directory block size.  xfs_da_grow_inode_int()
then subtracts more blocks than total ever held, underflowing it, and
hands the understated value to xfs_bmapi_write() as the remaining-space
hint the allocator sizes minleft from.

fsbcount is what the other caller of this conversion already reserves:
xfs_bmap_add_attrfork_local() sets dargs.total the same way, and it is
exactly what the single xfs_dir2_grow_inode() call underneath consumes.
The attribute counterpart in xrep_xattr_swap_prep() keeps its literal 1
because m_attr_geo->fsbcount is always 1.

Found by the reservation assert in xfs_da_grow_inode_int(), which Dave
Chinner hit running xfs/286 at 1k block size.

Fixes: b1991ee3e7cf ("xfs: online repair of directories")
Reported-by: Dave Chinner <dgc@xxxxxxxxxx>
Closes: https://lore.kernel.org/linux-xfs/ap-mIH9nTNkpWq9K@dread/
Signed-off-by: Javier Tia <javier@xxxxxxxxxxx>
---
 fs/xfs/scrub/dir_repair.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/xfs/scrub/dir_repair.c b/fs/xfs/scrub/dir_repair.c
index 31a23c5f386a..0a3d02d8f041 100644
--- a/fs/xfs/scrub/dir_repair.c
+++ b/fs/xfs/scrub/dir_repair.c
@@ -1488,7 +1488,7 @@ xrep_dir_swap_prep(
 			.geo		= sc->mp->m_dir_geo,
 			.whichfork	= XFS_DATA_FORK,
 			.trans		= sc->tp,
-			.total		= 1,
+			.total		= sc->mp->m_dir_geo->fsbcount,
 			.owner		= I_INO(sc->ip),
 		};
 

---
base-commit: 0ca15a1a115132dfebeee5447fd6abe46f66d61d
change-id: 20260908-b4-xrep-dir-total-3c77d0bcff51

Best regards,
-- 
Javier Tia <javier@xxxxxxxxxxx>