Re: [RFC ONLY 2/8] btrfs: move btrfs_io_context to volumes.h

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

On 2022/5/16 22:31, Johannes Thumshirn wrote:
> In preparation for upcoming changes, move 'struct btrfs_io_context' to
> volumes.h, so we can use it outside of volumes.c

In fact I don't think the naming itself (from myself) is that good.

It maybe a good idea to also do a rename here.

I have some bad alternatives, but doesn't seem better than the current
generic naming either:

- btrfs_io_mapping
- btrfs_mapping_context

Thus I guess the current name is chosen mostly due to lack of better ones.

Thanks,
Qu

>
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> ---
>   fs/btrfs/volumes.h | 90 +++++++++++++++++++++++-----------------------
>   1 file changed, 45 insertions(+), 45 deletions(-)
>
> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
> index bd297f23d19e..894d289a3b50 100644
> --- a/fs/btrfs/volumes.h
> +++ b/fs/btrfs/volumes.h
> @@ -32,6 +32,51 @@ struct btrfs_io_geometry {
>   	u64 raid56_stripe_offset;
>   };
>
> +struct btrfs_io_stripe {
> +	struct btrfs_device *dev;
> +	u64 physical;
> +	u64 length; /* only used for discard mappings */
> +};
> +
> +/*
> + * Context for IO subsmission for device stripe.
> + *
> + * - Track the unfinished mirrors for mirror based profiles
> + *   Mirror based profiles are SINGLE/DUP/RAID1/RAID10.
> + *
> + * - Contain the logical -> physical mapping info
> + *   Used by submit_stripe_bio() for mapping logical bio
> + *   into physical device address.
> + *
> + * - Contain device replace info
> + *   Used by handle_ops_on_dev_replace() to copy logical bios
> + *   into the new device.
> + *
> + * - Contain RAID56 full stripe logical bytenrs
> + */
> +struct btrfs_io_context {
> +	refcount_t refs;
> +	atomic_t stripes_pending;
> +	struct btrfs_fs_info *fs_info;
> +	u64 map_type; /* get from map_lookup->type */
> +	bio_end_io_t *end_io;
> +	struct bio *orig_bio;
> +	void *private;
> +	atomic_t error;
> +	int max_errors;
> +	int num_stripes;
> +	int mirror_num;
> +	int num_tgtdevs;
> +	int *tgtdev_map;
> +	/*
> +	 * logical block numbers for the start of each stripe
> +	 * The last one or two are p/q.  These are sorted,
> +	 * so raid_map[0] is the start of our full stripe
> +	 */
> +	u64 *raid_map;
> +	struct btrfs_io_stripe stripes[];
> +};
> +
>   /*
>    * Use sequence counter to get consistent device stat data on
>    * 32-bit processors.
> @@ -354,51 +399,6 @@ static inline void btrfs_bio_free_csum(struct btrfs_bio *bbio)
>   	}
>   }
>
> -struct btrfs_io_stripe {
> -	struct btrfs_device *dev;
> -	u64 physical;
> -	u64 length; /* only used for discard mappings */
> -};
> -
> -/*
> - * Context for IO subsmission for device stripe.
> - *
> - * - Track the unfinished mirrors for mirror based profiles
> - *   Mirror based profiles are SINGLE/DUP/RAID1/RAID10.
> - *
> - * - Contain the logical -> physical mapping info
> - *   Used by submit_stripe_bio() for mapping logical bio
> - *   into physical device address.
> - *
> - * - Contain device replace info
> - *   Used by handle_ops_on_dev_replace() to copy logical bios
> - *   into the new device.
> - *
> - * - Contain RAID56 full stripe logical bytenrs
> - */
> -struct btrfs_io_context {
> -	refcount_t refs;
> -	atomic_t stripes_pending;
> -	struct btrfs_fs_info *fs_info;
> -	u64 map_type; /* get from map_lookup->type */
> -	bio_end_io_t *end_io;
> -	struct bio *orig_bio;
> -	void *private;
> -	atomic_t error;
> -	int max_errors;
> -	int num_stripes;
> -	int mirror_num;
> -	int num_tgtdevs;
> -	int *tgtdev_map;
> -	/*
> -	 * logical block numbers for the start of each stripe
> -	 * The last one or two are p/q.  These are sorted,
> -	 * so raid_map[0] is the start of our full stripe
> -	 */
> -	u64 *raid_map;
> -	struct btrfs_io_stripe stripes[];
> -};
> -
>   struct btrfs_device_info {
>   	struct btrfs_device *dev;
>   	u64 dev_offset;