Re: [PATCH v6 20/22] erofs: implement fscache-based data read for data blobs

Gao Xiang
2022-03-28T09:51:04Z

On Fri, Mar 25, 2022 at 08:22:21PM +0800, Jeffle Xu wrote:
> Implements the data plane of reading data from data blob file over
> fscache.
>
> Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
> ---
> fs/erofs/data.c | 3 +++
> fs/erofs/fscache.c | 15 +++++++++++++--
> fs/erofs/internal.h | 1 +
> 3 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/fs/erofs/data.c b/fs/erofs/data.c
> index b4571bea93d5..b9a05de3c3b2 100644
> --- a/fs/erofs/data.c
> +++ b/fs/erofs/data.c
> @@ -206,6 +206,7 @@ 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)->bootstrap;
>
> if (map->m_deviceid) {
> down_read(&devs->rwsem);
> @@ -217,6 +218,7 @@ 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->blob;
> up_read(&devs->rwsem);
> } else if (devs->extra_devices) {
> down_read(&devs->rwsem);
> @@ -234,6 +236,7 @@ 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->blob;
> break;
> }
> }
> diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
> index d75958470645..cbb39657615e 100644
> --- a/fs/erofs/fscache.c
> +++ b/fs/erofs/fscache.c
> @@ -63,9 +63,20 @@ static int erofs_fscache_readpage_blob(struct file *data, struct page *page)
> static inline int erofs_fscache_get_map(struct erofs_map_blocks *map,
> struct super_block *sb)
> {

So erofs_fscache_get_map seems really unneeded...
erofs_map_dev can be used directly so we can avoid this patch.

Thanks,
Gao Xiang

> - struct erofs_sb_info *sbi = EROFS_SB(sb);
> + struct erofs_map_dev mdev;
> + int ret;
> +
> + mdev = (struct erofs_map_dev) {
> + .m_deviceid = map->m_deviceid,
> + .m_pa = map->m_pa,
> + };
> +
> + ret = erofs_map_dev(sb, &mdev);
> + if (ret)
> + return ret;
>
> - map->m_fscache = sbi->bootstrap;
> + map->m_fscache = mdev.m_fscache;
> + map->m_pa = mdev.m_pa;
> return 0;
> }
>
> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
> index 94a118caf580..cea08f12a2c3 100644
> --- a/fs/erofs/internal.h
> +++ b/fs/erofs/internal.h
> @@ -487,6 +487,7 @@ struct erofs_map_dev {
> struct block_device *m_bdev;
> struct dax_device *m_daxdev;
> u64 m_dax_part_off;
> + struct erofs_fscache *m_fscache;
>
> erofs_off_t m_pa;
> unsigned int m_deviceid;
> --
> 2.27.0