In order to support mounting multi-layer container image as a block device, add single block device with multiple devices feature for EROFS.
In this mode, all meta/data contents will be mapped into one block address. User could directly mount the block device by EROFS. Signed-off-by: Jia Zhu <[email protected]> Reviewed-by: Xin Yin <[email protected]> --- fs/erofs/data.c | 8 ++++++-- fs/erofs/super.c | 5 +++++ 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/fs/erofs/data.c b/fs/erofs/data.c index e16545849ea7..870b1f7fe1d4 100644 --- a/fs/erofs/data.c +++ b/fs/erofs/data.c @@ -195,9 +195,9 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map) { struct erofs_dev_context *devs = EROFS_SB(sb)->devs; struct erofs_device_info *dif; + bool flatdev = !!sb->s_bdev; int id; - /* primary device by default */ 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; @@ -210,12 +210,16 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map) up_read(&devs->rwsem); return -ENODEV; } + if (flatdev) { + map->m_pa += blknr_to_addr(dif->mapped_blkaddr); + map->m_deviceid = 0; + } 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) { + } else if (devs->extra_devices && !flatdev) { down_read(&devs->rwsem); idr_for_each_entry(&devs->tree, dif, id) { erofs_off_t startoff, length; diff --git a/fs/erofs/super.c b/fs/erofs/super.c index 19b1ae79cec4..4f9725b0950c 100644 --- a/fs/erofs/super.c +++ b/fs/erofs/super.c @@ -226,6 +226,7 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb, struct erofs_fscache *fscache; struct erofs_deviceslot *dis; struct block_device *bdev; + bool flatdev = !!sb->s_bdev; void *ptr; ptr = erofs_read_metabuf(buf, sb, erofs_blknr(*pos), EROFS_KMAP); @@ -248,6 +249,10 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb, if (IS_ERR(fscache)) return PTR_ERR(fscache); dif->fscache = fscache; + } else if (flatdev) { + dif->bdev = sb->s_bdev; + dif->dax_dev = EROFS_SB(sb)->dax_dev; + dif->dax_part_off = sbi->dax_part_off; } else { bdev = blkdev_get_by_path(dif->path, FMODE_READ | FMODE_EXCL, sb->s_type); -- 2.20.1
