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

[Jeffle Xu]

Implements the data plane of reading data from data blob file over
fscache.

Signed-off-by: Jeffle Xu <jeffl...@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)
 {
-       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

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