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btrfs: abort transaction on btrfs_reloc_cow_block()

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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@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
This commit is contained in:
Zhaolei 2015-08-06 21:56:58 +08:00 committed by Chris Mason
parent 147d256e09
commit 93314e3b64
1 changed files with 3 additions and 1 deletions
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4
fs/btrfs/ctree.c
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@ -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) {