Re: [PATCH v8 15/20] erofs: register fscache context for extra data blobs

From: Gao Xiang <xiang@kernel.org>
To: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: dhowells@redhat.com, linux-cachefs@redhat.com, xiang@kernel.org,
	chao@kernel.org, linux-erofs@lists.ozlabs.org,
	torvalds@linux-foundation.org, gregkh@linuxfoundation.org,
	willy@infradead.org, linux-fsdevel@vger.kernel.org,
	joseph.qi@linux.alibaba.com, bo.liu@linux.alibaba.com,
	tao.peng@linux.alibaba.com, gerry@linux.alibaba.com,
	eguan@linux.alibaba.com, linux-kernel@vger.kernel.org,
	luodaowen.backend@bytedance.com, tianzichen@kuaishou.com,
	fannaihao@baidu.com
Subject: Re: [PATCH v8 15/20] erofs: register fscache context for extra data blobs
Date: Thu, 7 Apr 2022 22:15:38 +0800	[thread overview]
Message-ID: <Yk7yCp2fwnbXeyuI@debian> (raw)
In-Reply-To: <20220406075612.60298-16-jefflexu@linux.alibaba.com>

On Wed, Apr 06, 2022 at 03:56:07PM +0800, Jeffle Xu wrote:
> Similar to the multi device mode, erofs could be mounted from one
> primary data blob (mandatory) and multiple extra data blobs (optional).
> 
> Register fscache context for each extra data blob.
> 
> Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
> ---
>  fs/erofs/data.c     |  3 +++
>  fs/erofs/internal.h |  2 ++
>  fs/erofs/super.c    | 25 +++++++++++++++++--------
>  3 files changed, 22 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/erofs/data.c b/fs/erofs/data.c
> index bc22642358ec..14b64d960541 100644
> --- a/fs/erofs/data.c
> +++ b/fs/erofs/data.c
> @@ -199,6 +199,7 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
>  	map->m_bdev = sb->s_bdev;
>  	map->m_daxdev = EROFS_SB(sb)->dax_dev;
>  	map->m_dax_part_off = EROFS_SB(sb)->dax_part_off;
> +	map->m_fscache = EROFS_SB(sb)->s_fscache;
>  
>  	if (map->m_deviceid) {
>  		down_read(&devs->rwsem);
> @@ -210,6 +211,7 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
>  		map->m_bdev = dif->bdev;
>  		map->m_daxdev = dif->dax_dev;
>  		map->m_dax_part_off = dif->dax_part_off;
> +		map->m_fscache = dif->fscache;
>  		up_read(&devs->rwsem);
>  	} else if (devs->extra_devices) {
>  		down_read(&devs->rwsem);
> @@ -227,6 +229,7 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
>  				map->m_bdev = dif->bdev;
>  				map->m_daxdev = dif->dax_dev;
>  				map->m_dax_part_off = dif->dax_part_off;
> +				map->m_fscache = dif->fscache;
>  				break;
>  			}
>  		}
> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
> index eb37b33bce37..90f7d6286a4f 100644
> --- a/fs/erofs/internal.h
> +++ b/fs/erofs/internal.h
> @@ -49,6 +49,7 @@ typedef u32 erofs_blk_t;
>  
>  struct erofs_device_info {
>  	char *path;
> +	struct erofs_fscache *fscache;
>  	struct block_device *bdev;
>  	struct dax_device *dax_dev;
>  	u64 dax_part_off;
> @@ -482,6 +483,7 @@ static inline int z_erofs_map_blocks_iter(struct inode *inode,
>  #endif	/* !CONFIG_EROFS_FS_ZIP */
>  
>  struct erofs_map_dev {
> +	struct erofs_fscache *m_fscache;
>  	struct block_device *m_bdev;
>  	struct dax_device *m_daxdev;
>  	u64 m_dax_part_off;
> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
> index 9498b899b73b..8c7181cd37e6 100644
> --- a/fs/erofs/super.c
> +++ b/fs/erofs/super.c
> @@ -259,15 +259,23 @@ static int erofs_init_devices(struct super_block *sb,
>  		}
>  		dis = ptr + erofs_blkoff(pos);
>  
> -		bdev = blkdev_get_by_path(dif->path,
> -					  FMODE_READ | FMODE_EXCL,
> -					  sb->s_type);
> -		if (IS_ERR(bdev)) {
> -			err = PTR_ERR(bdev);
> -			break;
> +		if (erofs_is_fscache_mode(sb)) {
> +			err = erofs_fscache_register_cookie(sb, &dif->fscache,
> +							    dif->path, false);
> +			if (err)
> +				break;
> +		} else {
> +			bdev = blkdev_get_by_path(dif->path,
> +						  FMODE_READ | FMODE_EXCL,
> +						  sb->s_type);
> +			if (IS_ERR(bdev)) {
> +				err = PTR_ERR(bdev);
> +				break;
> +			}
> +			dif->bdev = bdev;
> +			dif->dax_dev = fs_dax_get_by_bdev(bdev, &dif->dax_part_off);

Overly long line, please help split into 2 lines if possible.

Otherwise looks good,
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>

Thanks,
Gao Xiang

>  		}
> -		dif->bdev = bdev;
> -		dif->dax_dev = fs_dax_get_by_bdev(bdev, &dif->dax_part_off);
> +
>  		dif->blocks = le32_to_cpu(dis->blocks);
>  		dif->mapped_blkaddr = le32_to_cpu(dis->mapped_blkaddr);
>  		sbi->total_blocks += dif->blocks;
> @@ -701,6 +709,7 @@ static int erofs_release_device_info(int id, void *ptr, void *data)
>  	fs_put_dax(dif->dax_dev);
>  	if (dif->bdev)
>  		blkdev_put(dif->bdev, FMODE_READ | FMODE_EXCL);
> +	erofs_fscache_unregister_cookie(&dif->fscache);
>  	kfree(dif->path);
>  	kfree(dif);
>  	return 0;
> -- 
> 2.27.0
> 