Re: [PATCH] btrfs: Move missing device handling in a dedicate function

[Su Yue <l@damenly.su>]

On Tue 11 Jan 2022 at 18:00, Nikolay Borisov <nborisov@suse.com> 
wrote:

> This simplifies the code flow in read_one_chunk and makes error 
> handling
> when handling missing devices a bit simipler by reducing it to a 
> single
> check if something went wrong. No functional changes.
>
> Signed-off-by: Nikolay Borisov <nborisov@suse.com>
> ---
>  fs/btrfs/volumes.c | 39 +++++++++++++++++++++++++--------------
>  1 file changed, 25 insertions(+), 14 deletions(-)
>
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index b07d382d53a8..7518ac5c28dc 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -7060,6 +7060,27 @@ static void warn_32bit_meta_chunk(struct 
> btrfs_fs_info *fs_info,
>  }
>  #endif
>
> +static struct btrfs_device *handle_missing_device(struct 
> btrfs_fs_info *fs_info,
> +						  u64 devid, u8 
> *uuid)
> +{
> +	struct btrfs_device *dev;
> +
> +	if (!btrfs_test_opt(fs_info, DEGRADED)) {
> +		btrfs_report_missing_device(fs_info, devid, uuid, 
> true);
> +		return ERR_PTR(-ENOENT);
> +	}
> +
> +	dev = add_missing_dev(fs_info->fs_devices, devid, uuid);
> +	if (IS_ERR(dev)) {
> +		btrfs_err(fs_info, "failed to init missing dev 
> %llu: %ld",
> +			  devid, PTR_ERR(dev));
> +		return dev;
> +	}
> +	btrfs_report_missing_device(fs_info, devid, uuid, false);
> +
> +	return dev;
> +}
> +
>  static int read_one_chunk(struct btrfs_key *key, struct 
>  extent_buffer *leaf,
>  			  struct btrfs_chunk *chunk)
>  {
> @@ -7147,28 +7168,18 @@ static int read_one_chunk(struct 
> btrfs_key *key, struct extent_buffer *leaf,
>  				   BTRFS_UUID_SIZE);
>  		args.uuid = uuid;
>  		map->stripes[i].dev = 
>  btrfs_find_device(fs_info->fs_devices, &args);
> -		if (!map->stripes[i].dev &&
> -		    !btrfs_test_opt(fs_info, DEGRADED)) {
> -			free_extent_map(em);
> -			btrfs_report_missing_device(fs_info, 
> devid, uuid, true);
> -			return -ENOENT;
> -		}
>  		if (!map->stripes[i].dev) {
> -			map->stripes[i].dev =
> - 
> add_missing_dev(fs_info->fs_devices, devid,
> -						uuid);
> +			map->stripes[i].dev = 
> handle_missing_device(fs_info,
> + 
> devid, uuid);
>  			if (IS_ERR(map->stripes[i].dev)) {
>  				free_extent_map(em);
> -				btrfs_err(fs_info,
> -					"failed to init missing 
> dev %llu: %ld",
> -					devid, 
> PTR_ERR(map->stripes[i].dev));
>  				return 
>  PTR_ERR(map->stripes[i].dev);
> +
>

No need for the blank line, I think.

Reviewed-by: Su Yue <l@damenly.su>

--
Su
>  			}
> -			btrfs_report_missing_device(fs_info, 
> devid, uuid, false);
>  		}
> +
>  		set_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
>  				&(map->stripes[i].dev->dev_state));
> -
>  	}
>
>  	write_lock(&map_tree->lock);