diff options
authorDave Chinner <>2013-06-12 12:19:08 +1000
committerBen Myers <>2013-06-14 15:59:31 -0500
commit088c9f67c3f53339d2bc20b42a9cb904901fdc5d (patch)
parent5170711df79b284cf95b3924322e8ac4c0fd6c76 (diff)
xfs: ensure btree root split sets blkno correctly
For CRC enabled filesystems, the BMBT is rooted in an inode, so it passes through a different code path on root splits than the freespace and inode btrees. This is much less traversed by xfstests than the other trees. When testing on a 1k block size filesystem, I've been seeing ASSERT failures in generic/234 like: XFS: Assertion failed: cur->bc_btnum != XFS_BTNUM_BMAP || cur->bc_private.b.allocated == 0, file: fs/xfs/xfs_btree.c, line: 317 which are generally preceded by a lblock check failure. I noticed this in the bmbt stats: $ pminfo -f xfs.btree.block_map xfs.btree.block_map.lookup value 39135 value 268432 xfs.btree.block_map.insrec value 15786 xfs.btree.block_map.delrec value 13884 xfs.btree.block_map.newroot value 2 xfs.btree.block_map.killroot value 0 ..... Very little coverage of root splits and merges. Indeed, on a 4k filesystem, block_map.newroot and block_map.killroot are both zero. i.e. the code is not exercised at all, and it's the only generic btree infrastructure operation that is not exercised by a default run of xfstests. Turns out that on a 1k filesystem, generic/234 accounts for one of those two root splits, and that is somewhat of a smoking gun. In fact, it's the same problem we saw in the directory/attr code where headers are memcpy()d from one block to another without updating the self describing metadata. Simple fix - when copying the header out of the root block, make sure the block number is updated correctly. Signed-off-by: Dave Chinner <> Reviewed-by: Ben Myers <> Signed-off-by: Ben Myers <> (cherry picked from commit ade1335afef556df6538eb02e8c0dc91fbd9cc37)
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/xfs/xfs_btree.c b/fs/xfs/xfs_btree.c
index 8804b8a3c310..0903960410a2 100644
--- a/fs/xfs/xfs_btree.c
+++ b/fs/xfs/xfs_btree.c
@@ -2544,7 +2544,17 @@ xfs_btree_new_iroot(
if (error)
goto error0;
+ /*
+ * we can't just memcpy() the root in for CRC enabled btree blocks.
+ * In that case have to also ensure the blkno remains correct
+ */
memcpy(cblock, block, xfs_btree_block_len(cur));
+ if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS) {
+ if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
+ cblock->bb_u.l.bb_blkno = cpu_to_be64(cbp->b_bn);
+ else
+ cblock->bb_u.s.bb_blkno = cpu_to_be64(cbp->b_bn);
+ }
be16_add_cpu(&block->bb_level, 1);
xfs_btree_set_numrecs(block, 1);