Re: [PATCH 4/5] Btrfs: fix inode cache waiters hanging on path allocation failure

Nikolay Borisov
2019-07-08T06:20:59Z

On 4.07.19 г. 18:24 ч., fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
>
> If the caching thread fails to allocate a path, it returns without waking
> up any cache waiters, leaving them hang forever. Fix this by following the
> same approach as when we fail to start the caching thread: print an error
> message, disable inode caching and make the wakers fallback to non-caching
> mode behaviour (calling btrfs_find_free_objectid()).
>
> Fixes: 581bb050941b4f ("Btrfs: Cache free inode numbers in memory")
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

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

> ---
> fs/btrfs/inode-map.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
> index 05b8c9927f29..4820e05ea6bd 100644
> --- a/fs/btrfs/inode-map.c
> +++ b/fs/btrfs/inode-map.c
> @@ -41,8 +41,10 @@ static int caching_kthread(void *data)
> return 0;
>
> path = btrfs_alloc_path();
> - if (!path)
> + if (!path) {
> + fail_caching_thread(root);
> return -ENOMEM;
> + }
>
> /* Since the commit root is read-only, we can safely skip locking. */
> path->skip_locking = 1;
>