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xfs: fix the minrecs logic when dealing with inode root child blocks

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The comment and logic in xchk_btree_check_minrecs for dealing with
inode-rooted btrees isn't quite correct.  While the direct children of
the inode root are allowed to have fewer records than what would
normally be allowed for a regular ondisk btree block, this is only true
if there is only one child block and the number of records don't fit in
the inode root.

Fixes: 08a3a692ef ("xfs: btree scrub should check minrecs")
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Darrick J. Wong 2020-11-08 16:32:41 -08:00
parent 2bd3fa793a
commit e95b6c3ef1
1 changed files with 28 additions and 19 deletions
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47
fs/xfs/scrub/btree.c
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@ -452,32 +452,41 @@ xchk_btree_check_minrecs(
int level, int level,
struct xfs_btree_block *block) struct xfs_btree_block *block)
{ {
unsigned int numrecs; struct xfs_btree_cur *cur = bs->cur;
int ok_level; unsigned int root_level = cur->bc_nlevels - 1;
unsigned int numrecs = be16_to_cpu(block->bb_numrecs);
numrecs = be16_to_cpu(block->bb_numrecs);
/* More records than minrecs means the block is ok. */ /* More records than minrecs means the block is ok. */
if (numrecs >= bs->cur->bc_ops->get_minrecs(bs->cur, level)) if (numrecs >= cur->bc_ops->get_minrecs(cur, level))
return; return;
/* /*
* Certain btree blocks /can/ have fewer than minrecs records. Any * For btrees rooted in the inode, it's possible that the root block
* level greater than or equal to the level of the highest dedicated * contents spilled into a regular ondisk block because there wasn't
* btree block are allowed to violate this constraint. * enough space in the inode root. The number of records in that
* * child block might be less than the standard minrecs, but that's ok
* For a btree rooted in a block, the btree root can have fewer than * provided that there's only one direct child of the root.
* minrecs records. If the btree is rooted in an inode and does not
* store records in the root, the direct children of the root and the
* root itself can have fewer than minrecs records.
*/ */
ok_level = bs->cur->bc_nlevels - 1; if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
if (bs->cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) level == cur->bc_nlevels - 2) {
ok_level--; struct xfs_btree_block *root_block;
if (level >= ok_level) struct xfs_buf *root_bp;
return; int root_maxrecs;
xchk_btree_set_corrupt(bs->sc, bs->cur, level); root_block = xfs_btree_get_block(cur, root_level, &root_bp);
root_maxrecs = cur->bc_ops->get_dmaxrecs(cur, root_level);
if (be16_to_cpu(root_block->bb_numrecs) != 1 ||
numrecs <= root_maxrecs)
xchk_btree_set_corrupt(bs->sc, cur, level);
return;
}
/*
* Otherwise, only the root level is allowed to have fewer than minrecs
* records or keyptrs.
*/
if (level < root_level)
xchk_btree_set_corrupt(bs->sc, cur, level);
} }
/* /*