erofs: support for mounting a single block device with multiple devices
Commit Message
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 <zhujia.zj@bytedance.com>
Reviewed-by: Xin Yin <yinxin.x@bytedance.com>
---
fs/erofs/data.c | 8 ++++++--
fs/erofs/super.c | 5 +++++
2 files changed, 11 insertions(+), 2 deletions(-)
Comments
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@bytedance.com>
> Reviewed-by: Xin Yin <yinxin.x@bytedance.com>
> ---
> 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);
在 2023/3/1 15:08, Gao Xiang 写道:
> 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.
>
Thanks, I would revise it.
>>
>> 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@bytedance.com>
>> Reviewed-by: Xin Yin <yinxin.x@bytedance.com>
>> ---
>> 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?
>
I'll revise that in next version.
> Also, did you test this patch?
I've tested the patch using the following steps mentioned by
https://github.com/dragonflyoss/image-service/pull/1111
1. Compose a (nbd)block device from an EROFS image.
2. mount -t erofs /dev/nbdx /mnt/
3. compare the md5sum between source dir and /mnt dir.
>
> 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);
@@ -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;
@@ -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);