Hi Jia,
On 2023/3/1 15:04, Jia Zhu wrote:
In order to support mounting multi-layer container image as a block
device, add single block device with multiple devices feature for EROFS.
In order to support mounting multi-blob container image as a single
flattened block device, add flattened block device 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 <zhujia.zj@xxxxxxxxxxxxx>
Reviewed-by: Xin Yin <yinxin.x@xxxxxxxxxxxxx>
---
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;
I'd like to land it in sbi and set it in advance?
Also, did you test this patch?
Thanks,
Gao Xiang
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);
