From: "Darrick J. Wong" darrick.wong@oracle.com
stable inclusion from linux-4.19.160 commit 804b269c252445d3b98497c8b02db0152c65cd63
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[ Upstream commit e95b6c3ef1311dd7b20467d932a24b6d0fd88395 ]
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: 08a3a692ef58 ("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 Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- fs/xfs/scrub/btree.c | 45 ++++++++++++++++++++++++++------------------ 1 file changed, 27 insertions(+), 18 deletions(-)
diff --git a/fs/xfs/scrub/btree.c b/fs/xfs/scrub/btree.c index 4ae959f7ad2c..c924fe3cdad6 100644 --- a/fs/xfs/scrub/btree.c +++ b/fs/xfs/scrub/btree.c @@ -450,32 +450,41 @@ xchk_btree_check_minrecs( int level, struct xfs_btree_block *block) { - unsigned int numrecs; - int ok_level; - - numrecs = be16_to_cpu(block->bb_numrecs); + struct xfs_btree_cur *cur = bs->cur; + unsigned int root_level = cur->bc_nlevels - 1; + unsigned int numrecs = be16_to_cpu(block->bb_numrecs);
/* 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;
/* - * Certain btree blocks /can/ have fewer than minrecs records. Any - * level greater than or equal to the level of the highest dedicated - * btree block are allowed to violate this constraint. - * - * For a btree rooted in a block, the btree root can have fewer than - * 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. + * For btrees rooted in the inode, it's possible that the root block + * contents spilled into a regular ondisk block because there wasn't + * 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 + * provided that there's only one direct child of the root. */ - ok_level = bs->cur->bc_nlevels - 1; - if (bs->cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) - ok_level--; - if (level >= ok_level) + if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) && + level == cur->bc_nlevels - 2) { + struct xfs_btree_block *root_block; + struct xfs_buf *root_bp; + int root_maxrecs; + + 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; + }
- xchk_btree_set_corrupt(bs->sc, bs->cur, level); + /* + * 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); }
/*