When btrfs_reloc_cow_block() failed in __btrfs_cow_block(), current
code just return a err-value to caller, but leave new_created extent
buffer exist and locked.
Then subsequent code (in relocate) try to lock above eb again,
and caused deadlock without any dmesg.
(eb lock use wait_event(), so no lockdep message)
It is hard to do recover work in __btrfs_cow_block() at this error
point, but we can abort transaction to avoid deadlock and operate on
unstable state.a
It also helps developer to find wrong place quickly.
(better than a frozen fs without any dmesg before patch)
Signed-off-by: Zhao Lei <zhaolei@xxxxxxxxxxxxxx>
---
fs/btrfs/ctree.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 54114b4..5f745ea 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1159,8 +1159,10 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
ret = btrfs_reloc_cow_block(trans, root, buf, cow);
- if (ret)
+ if (ret) {
+ btrfs_abort_transaction(trans, root, ret);
return ret;
+ }
}
if (buf == root->node) {
--
1.8.5.1
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