Re: bcache: unlock new_nodes[i]->write_lock in btree_gc_coalesce

From: Zhiqiang Liu
Date: Mon Apr 20 2020 - 02:55:53 EST


friendly ping...

On 2020/4/15 19:42, Zhiqiang Liu wrote:
> From: Zhiqiang Liu <liuzhiqiang26@xxxxxxxxxx>
>
> coccicheck reports:
> drivers/md//bcache/btree.c:1538:1-7:ÂprecedingÂlockÂonÂlineÂ1417
>
> After obtaining new_nodes[i]->write_lock, we may go to out_nocoalesce
> tag without releasing lock. Here, we add a new tag
> 'out_unlock_nocoalesce' before out_nocoalesce tag to release
> new_nodes[i]->write_lock.
>
> Fixes: 2a285686c1 ("bcache: btree locking rework")
> Signed-off-by: Zhiqiang Liu <liuzhiqiang26@xxxxxxxxxx>
> ---
> drivers/md/bcache/btree.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
> index fa872df4e770..cad8b0b97e33 100644
> --- a/drivers/md/bcache/btree.c
> +++ b/drivers/md/bcache/btree.c
> @@ -1447,7 +1447,7 @@ static int btree_gc_coalesce(struct btree *b, struct btree_op *op,
> if (__set_blocks(n1, n1->keys + n2->keys,
> block_bytes(b->c)) >
> btree_blocks(new_nodes[i]))
> - goto out_nocoalesce;
> + goto out_unlock_nocoalesce;
>
> keys = n2->keys;
> /* Take the key of the node we're getting rid of */
> @@ -1476,7 +1476,7 @@ static int btree_gc_coalesce(struct btree *b, struct btree_op *op,
>
> if (__bch_keylist_realloc(&keylist,
> bkey_u64s(&new_nodes[i]->key)))
> - goto out_nocoalesce;
> + goto out_unlock_nocoalesce;
>
> bch_btree_node_write(new_nodes[i], &cl);
> bch_keylist_add(&keylist, &new_nodes[i]->key);
> @@ -1522,6 +1522,10 @@ static int btree_gc_coalesce(struct btree *b, struct btree_op *op,
> /* Invalidated our iterator */
> return -EINTR;
>
> +out_unlock_nocoalesce:
> + for (i = 0; i < nodes; i++)
> + mutex_unlock(&new_nodes[i]->write_lock);
> +
> out_nocoalesce:
> closure_sync(&cl);
>