[PATCH 1/3] xfs: actually check xfs_btree_check_block return in xfs_btree_islastblock

Darrick J. Wong
2019-11-11T01:18:55Z

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

Coverity points out that xfs_btree_islastblock doesn't check the return
value of xfs_btree_check_block. Since the question "Does the cursor
point to the last block in this level?" only makes sense if the caller
previously performed a lookup or seek operation, the block should
already have been checked.

Therefore, check the return value in an ASSERT and turn the whole thing
into a static inline predicate.

Coverity-id: 114069
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/libxfs/xfs_btree.c | 19 -------------------
fs/xfs/libxfs/xfs_btree.h | 25 +++++++++++++++++--------
2 files changed, 17 insertions(+), 27 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index feab5b307c45..3d48878ab298 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -714,25 +714,6 @@ xfs_btree_get_bufs(
return xfs_trans_get_buf(tp, mp->m_ddev_targp, d, mp->m_bsize, 0);
}

-/*
- * Check for the cursor referring to the last block at the given level.
- */
-int /* 1=is last block, 0=not last block */
-xfs_btree_islastblock(
- xfs_btree_cur_t *cur, /* btree cursor */
- int level) /* level to check */
-{
- struct xfs_btree_block *block; /* generic btree block pointer */
- xfs_buf_t *bp; /* buffer containing block */
-
- block = xfs_btree_get_block(cur, level, &bp);
- xfs_btree_check_block(cur, block, level, bp);
- if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
- return block->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK);
- else
- return block->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK);
-}
-
/*
* Change the cursor to point to the first record at the given level.
* Other levels are unaffected.
diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index 6670120cd690..fb9b2121c628 100644
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -317,14 +317,6 @@ xfs_btree_get_bufs(
xfs_agnumber_t agno, /* allocation group number */
xfs_agblock_t agbno); /* allocation group block number */

-/*
- * Check for the cursor referring to the last block at the given level.
- */
-int /* 1=is last block, 0=not last block */
-xfs_btree_islastblock(
- xfs_btree_cur_t *cur, /* btree cursor */
- int level); /* level to check */
-
/*
* Compute first and last byte offsets for the fields given.
* Interprets the offsets table, which contains struct field offsets.
@@ -524,4 +516,21 @@ int xfs_btree_has_record(struct xfs_btree_cur *cur, union xfs_btree_irec *low,
union xfs_btree_irec *high, bool *exists);
bool xfs_btree_has_more_records(struct xfs_btree_cur *cur);

+/* Does this cursor point to the last block in the given level? */
+static inline bool
+xfs_btree_islastblock(
+ xfs_btree_cur_t *cur,
+ int level)
+{
+ struct xfs_btree_block *block;
+ struct xfs_buf *bp;
+
+ block = xfs_btree_get_block(cur, level, &bp);
+ ASSERT(block && xfs_btree_check_block(cur, block, level, bp) == 0);
+
+ if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
+ return block->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK);
+ return block->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK);
+}
+
#endif /* __XFS_BTREE_H__ */