Re: [PATCH 1/2] btrfs: fix device order consistency

[Nikolay Borisov <nborisov@suse.com>]

On 18.01.2018 04:32, Anand Jain wrote:
> By maintaining the device order consistency it makes reproducing
> the problem more consistent. So fix this by having the devices

Which problem is that ?

> sorted by some order within the kernel, lets say by devid.
> 
> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> ---
>  fs/btrfs/volumes.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index d393808071d5..68be58a5b03f 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -27,6 +27,7 @@
>  #include <linux/raid/pq.h>
>  #include <linux/semaphore.h>
>  #include <linux/uuid.h>
> +#include <linux/list_sort.h>
>  #include <asm/div64.h>
>  #include "ctree.h"
>  #include "extent_map.h"
> @@ -1108,6 +1109,20 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
>  	return ret;
>  }
>  
> +static int device_sort(void *priv, struct list_head *a, struct list_head *b)
> +{
> +	struct btrfs_device *dev1, *dev2;
> +
> +	dev1 = list_entry(a, struct btrfs_device, dev_list);
> +	dev2 = list_entry(b, struct btrfs_device, dev_list);
> +
> +	if (dev1->devid < dev2->devid)
> +		return -1;
> +	else if (dev1->devid > dev2->devid)
> +		return 1;
> +	return 0;
> +}
> +
>  int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
>  		       fmode_t flags, void *holder)
>  {
> @@ -1118,6 +1133,7 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
>  		fs_devices->opened++;
>  		ret = 0;
>  	} else {
> +		list_sort(NULL, &fs_devices->devices, device_sort);
>  		ret = __btrfs_open_devices(fs_devices, flags, holder);
>  	}
>  	mutex_unlock(&uuid_mutex);
>