Messages in this thread Patch in this message | | | Date | Wed, 1 Mar 2023 15:44:37 +0800 | Subject | Re: Re: [PATCH] erofs: support for mounting a single block device with multiple devices | From | Jia Zhu <> |
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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);
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