erofs: register fscache context for extra data blobs

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>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220425122143.56815-17-jefflexu@linux.alibaba.comAcked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

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;
 			}
 		}

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;
@@ -457,6 +458,7 @@ 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;

fs/erofs/super.c

@@ -260,7 +260,12 @@ static int erofs_init_devices(struct super_block *sb,
 		}
 		dis = ptr + erofs_blkoff(pos);
 
-		if (!erofs_is_fscache_mode(sb)) {
+		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);
@@ -750,6 +755,7 @@ 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;