[PATCH 4/4] xfs: compare btree block keys to parent block's keys during scrub

Darrick J. Wong
2017-10-26T05:49:45Z

From: Darrick J. Wong <darrick.wong@oracle.com>

When we're done checking all the records/keys in a btree block, compute
the low and high key of the block and compare them to the associated key
in the parent btree block.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/libxfs/xfs_btree.c | 4 ++--
fs/xfs/libxfs/xfs_btree.h | 4 ++++
fs/xfs/scrub/btree.c | 46 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index b3cd82a..848f371 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -2027,7 +2027,7 @@ xfs_btree_lookup(
}

/* Find the high key storage area from a regular key. */
-STATIC union xfs_btree_key *
+union xfs_btree_key *
xfs_btree_high_key_from_key(
struct xfs_btree_cur *cur,
union xfs_btree_key *key)
@@ -2101,7 +2101,7 @@ xfs_btree_get_node_keys(
}

/* Derive the keys for any btree block. */
-STATIC void
+void
xfs_btree_get_keys(
struct xfs_btree_cur *cur,
struct xfs_btree_block *block,
diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index be82f41..b57501c 100644
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -541,5 +541,9 @@ int64_t xfs_btree_diff_two_ptrs(struct xfs_btree_cur *cur,
void xfs_btree_get_sibling(struct xfs_btree_cur *cur,
struct xfs_btree_block *block,
union xfs_btree_ptr *ptr, int lr);
+void xfs_btree_get_keys(struct xfs_btree_cur *cur,
+ struct xfs_btree_block *block, union xfs_btree_key *key);
+union xfs_btree_key *xfs_btree_high_key_from_key(struct xfs_btree_cur *cur,
+ union xfs_btree_key *key);

#endif /* __XFS_BTREE_H__ */
diff --git a/fs/xfs/scrub/btree.c b/fs/xfs/scrub/btree.c
index 9ccf763..9e8b67a 100644
--- a/fs/xfs/scrub/btree.c
+++ b/fs/xfs/scrub/btree.c
@@ -358,6 +358,50 @@ xfs_scrub_btree_get_block(
}

/*
+ * Check that the low and high keys of this block match the keys stored
+ * in the parent block.
+ */
+STATIC void
+xfs_scrub_btree_block_keys(
+ struct xfs_scrub_btree *bs,
+ int level,
+ struct xfs_btree_block *block)
+{
+ union xfs_btree_key block_keys;
+ struct xfs_btree_cur *cur = bs->cur;
+ union xfs_btree_key *high_bk;
+ union xfs_btree_key *parent_keys;
+ union xfs_btree_key *high_pk;
+ struct xfs_btree_block *parent_block;
+ struct xfs_buf *bp;
+
+ if (level >= cur->bc_nlevels - 1)
+ return;
+
+ /* Calculate the keys for this block. */
+ xfs_btree_get_keys(cur, block, &block_keys);
+
+ /* Obtain the parent's copy of the keys for this block. */
+ parent_block = xfs_btree_get_block(cur, level + 1, &bp);
+ parent_keys = xfs_btree_key_addr(cur, cur->bc_ptrs[level + 1],
+ parent_block);
+
+ if (cur->bc_ops->diff_two_keys(cur, &block_keys, parent_keys) != 0)
+ xfs_scrub_btree_set_corrupt(bs->sc, cur, 1);
+
+ if (!(cur->bc_flags & XFS_BTREE_OVERLAPPING))
+ return;
+
+ /* Get high keys */
+ high_bk = xfs_btree_high_key_from_key(cur, &block_keys);
+ high_pk = xfs_btree_high_key_addr(cur, cur->bc_ptrs[level + 1],
+ parent_block);
+
+ if (cur->bc_ops->diff_two_keys(cur, high_bk, high_pk) != 0)
+ xfs_scrub_btree_set_corrupt(bs->sc, cur, 1);
+}
+
+/*
* Visit all nodes and leaves of a btree. Check that all pointers and
* records are in order, that the keys reflect the records, and use a callback
* so that the caller can verify individual records.
@@ -418,6 +462,7 @@ xfs_scrub_btree(
/* End of leaf, pop back towards the root. */
if (cur->bc_ptrs[level] >
be16_to_cpu(block->bb_numrecs)) {
+ xfs_scrub_btree_block_keys(&bs, level, block);
if (level < cur->bc_nlevels - 1)
cur->bc_ptrs[level + 1]++;
level++;
@@ -442,6 +487,7 @@ xfs_scrub_btree(

/* End of node, pop back towards the root. */
if (cur->bc_ptrs[level] > be16_to_cpu(block->bb_numrecs)) {
+ xfs_scrub_btree_block_keys(&bs, level, block);
if (level < cur->bc_nlevels - 1)
cur->bc_ptrs[level + 1]++;
level++;