[PATCH v1] erofs-utils: mkfs: Implement 'dsunit' alignment on blobdev

[Gao Xiang]

Hi,

On 2025/8/20 17:00, Friendy.Su at sony.com wrote:
> Hi, Gao,
> 
> Thanks for your review !
> 
>> As for this patch, what if the inode itself is
>> chunk-deduplicated, could we apply this if the inode
>> only has one new chunk instead at least for now?
> 
> Do you mean inode has 3 chunks, chunk#2 and chunk#3 duplicate chunck#1?
> 
> This patch only makes the 1st chunk exactly written to blobdev aligned on dsunit. Deduplicated chunks will not be written to blobdev.
> 
> In example above, chunk#1 is written to dsunit aligned block addr, chunk#2,#3 are not written. The next file will be written from next dsunit alignment addr.

What's your `--chunksize` ? consider the following:

  chunksize = 4096
  dsunit = 512 = 2M

and two inodes:

inode A (8k)    2M, 2M+4k

inode B (12k)   4M, 2M, 4M+4k, 4M+8k?

Is it possible? what's the expected behavior of
this case.

Thanks,
Gao Xiang

> 
> Best Regards
> Friendy Su