[PATCH v3 0/4] erofs-utils: implement the FULLDATA rebuild mode

Gao Xiang hsiangkao at linux.alibaba.com
Wed Apr 15 12:07:05 AEST 2026



On 2026/4/15 03:10, Lucas Karpinski wrote:
> Currently, erofs-utils supports backing blobs for multi-image setups.  This
> implements the FULLDATA import which allows for the merging of multiple
> source images into a single self-contained erofs image.
> 
> To optimize the rebuild process, erofs_io_xcopy() is used to leverage the
> copy_file_range(2) if available. This bypasses userspace buffering and
> enables kernel side data transfers.
>   
> Verification: Built same image with default rebuild and rebuild with
> FULLDATA. Then ran F-i-f/tdiff comparing the two.
> 
> changes in v3:
> - adhere to uniaddress semantics.
> - take advantage of existing infrastructure which allows us to drop a
>    significant amount of complexity + code.
> 
> changes in v2:
> - reworked erofs_rebuild_load_trees_full into
>    erofs_mkfs_rebuild_load_trees.
> - removed --merge option (use --clean=data instead).
> - updated man.
> 
> Signed-off-by: Lucas Karpinski <lkarpinski at nvidia.com>

Overally looks good to me, will apply to -experimental branch.

... Would you mind taking some time working on some tests
in experimental-tests branch?

Thanks,
Gao Xiang


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