Re: [PATCH] btrfs: Remove alloc_list splice in btrfs_prepare_sprout

[Josef Bacik <josef@toxicpanda.com>]

On 8/12/20 9:26 AM, Nikolay Borisov wrote:
> btrfs_prepare_sprout is called when the first rw device is added to a
> seed filesystem. This means the filesystem can't have its alloc_list
> be non-empty, since seed filesystems are read only. Simply remove the
> code altogether.
> 
> Signed-off-by: Nikolay Borisov <nborisov@suse.com>
> ---
>   fs/btrfs/volumes.c | 4 ----
>   1 file changed, 4 deletions(-)
> 
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 71480175e8cb..4bae30b9c944 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -2385,10 +2385,6 @@ static int btrfs_prepare_sprout(struct btrfs_fs_info *fs_info)
>   	list_for_each_entry(device, &seed_devices->devices, dev_list)
>   		device->fs_devices = seed_devices;
>   
> -	mutex_lock(&fs_info->chunk_mutex);
> -	list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
> -	mutex_unlock(&fs_info->chunk_mutex);
> -
>   	fs_devices->seeding = false;
>   	fs_devices->num_devices = 0;
>   	fs_devices->open_devices = 0;
> 

Ok this took me a second, we swap out the seed_devices and the new fs_devices is 
what becomes the main thing for the fs.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef