[PATCH] btrfs: zoned: fix wrong mutex unlock on failure to allocate log root tree

[PATCH] btrfs: zoned: fix wrong mutex unlock on failure to allocate log root tree

[fdmanana]

From: Filipe Manana <fdmanana@suse.com>

When syncing the log, if we fail to allocate the root node for the log
root tree:

1) We are unlocking fs_info->tree_log_mutex, but at this point we have
   not yet locked this mutex;

2) We have locked fs_info->tree_root->log_mutex, but we end up not
   unlocking it;

So fix this by unlocking fs_info->tree_root->log_mutex instead of
fs_info->tree_log_mutex.

Fixes: e75f9fd194090e ("btrfs: zoned: move log tree node allocation out of log_root_tree->log_mutex")
CC: stable@vger.kernel.org # 5.13+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/tree-log.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 8471837e7eb9..9fd0348be7f5 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -3173,7 +3173,7 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
 		if (!log_root_tree->node) {
 			ret = btrfs_alloc_log_tree_node(trans, log_root_tree);
 			if (ret) {
-				mutex_unlock(&fs_info->tree_log_mutex);
+				mutex_unlock(&fs_info->tree_root->log_mutex);
 				goto out;
 			}
 		}
-- 
2.30.2

Re: [PATCH] btrfs: zoned: fix wrong mutex unlock on failure to allocate log root tree

[Nikolay Borisov]

On 7.07.21 г. 14:23, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
> 
> When syncing the log, if we fail to allocate the root node for the log
> root tree:
> 
> 1) We are unlocking fs_info->tree_log_mutex, but at this point we have
>    not yet locked this mutex;
> 
> 2) We have locked fs_info->tree_root->log_mutex, but we end up not
>    unlocking it;
> 
> So fix this by unlocking fs_info->tree_root->log_mutex instead of
> fs_info->tree_log_mutex.
> 
> Fixes: e75f9fd194090e ("btrfs: zoned: move log tree node allocation out of log_root_tree->log_mutex")
> CC: stable@vger.kernel.org # 5.13+
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Reviewed-by: Nikolay Borisov <nborisov@suse.com>

Re: [PATCH] btrfs: zoned: fix wrong mutex unlock on failure to allocate log root tree

[Johannes Thumshirn]

On 07/07/2021 13:23, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
> 
> When syncing the log, if we fail to allocate the root node for the log
> root tree:
> 
> 1) We are unlocking fs_info->tree_log_mutex, but at this point we have
>    not yet locked this mutex;
> 
> 2) We have locked fs_info->tree_root->log_mutex, but we end up not
>    unlocking it;
> 
> So fix this by unlocking fs_info->tree_root->log_mutex instead of
> fs_info->tree_log_mutex.
> 
> Fixes: e75f9fd194090e ("btrfs: zoned: move log tree node allocation out of log_root_tree->log_mutex")
> CC: stable@vger.kernel.org # 5.13+
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Good catch!
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Re: [PATCH] btrfs: zoned: fix wrong mutex unlock on failure to allocate log root tree

[David Sterba]

On Wed, Jul 07, 2021 at 12:23:45PM +0100, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
> 
> When syncing the log, if we fail to allocate the root node for the log
> root tree:
> 
> 1) We are unlocking fs_info->tree_log_mutex, but at this point we have
>    not yet locked this mutex;
> 
> 2) We have locked fs_info->tree_root->log_mutex, but we end up not
>    unlocking it;
> 
> So fix this by unlocking fs_info->tree_root->log_mutex instead of
> fs_info->tree_log_mutex.
> 
> Fixes: e75f9fd194090e ("btrfs: zoned: move log tree node allocation out of log_root_tree->log_mutex")
> CC: stable@vger.kernel.org # 5.13+
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Added to misc-next, thanks.