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authorGuo Xuenan <guoxuenan@huawei.com>2022-12-01 09:36:16 -0800
committerDarrick J. Wong <djwong@kernel.org>2022-12-01 09:36:16 -0800
commit8c25febf23963431686f04874b96321288504127 (patch)
treeb29519937af627ee45b31cbdd365076b7217825c
parent948961964b2404ea474a3643fc0e1b77c592bb7c (diff)
xfs: get rid of assert from xfs_btree_islastblock
xfs_btree_check_block contains debugging knobs. With XFS_DEBUG setting up, turn on the debugging knob can trigger the assert of xfs_btree_islastblock, test script as follows: while true do mount $disk $mountpoint fsstress -d $testdir -l 0 -n 10000 -p 4 >/dev/null echo 1 > /sys/fs/xfs/sda/errortag/btree_chk_sblk sleep 10 umount $mountpoint done Kick off fsstress and only *then* turn on the debugging knob. If it happens that the knob gets turned on after the cntbt lookup succeeds but before the call to xfs_btree_islastblock, then we *can* end up in the situation where a previously checked btree block suddenly starts returning EFSCORRUPTED from xfs_btree_check_block. Kaboom. Darrick give a very detailed explanation as follows: Looking back at commit 27d9ee577dcce, I think the point of all this was to make sure that the cursor has actually performed a lookup, and that the btree block at whatever level we're asking about is ok. If the caller hasn't ever done a lookup, the bc_levels array will be empty, so cur->bc_levels[level].bp pointer will be NULL. The call to xfs_btree_get_block will crash anyway, so the "ASSERT(block);" part is pointless. If the caller did a lookup but the lookup failed due to block corruption, the corresponding cur->bc_levels[level].bp pointer will also be NULL, and we'll still crash. The "ASSERT(xfs_btree_check_block);" logic is also unnecessary. If the cursor level points to an inode root, the block buffer will be incore, so it had better always be consistent. If the caller ignores a failed lookup after a successful one and calls this function, the cursor state is garbage and the assert wouldn't have tripped anyway. So get rid of the assert. Fixes: 27d9ee577dcc ("xfs: actually check xfs_btree_check_block return in xfs_btree_islastblock") Signed-off-by: Guo Xuenan <guoxuenan@huawei.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
-rw-r--r--fs/xfs/libxfs/xfs_btree.h1
1 files changed, 0 insertions, 1 deletions
diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index eef27858a013..29c4b4ccb909 100644
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -556,7 +556,6 @@ xfs_btree_islastblock(
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);