[PATCH v2 0/5] erofs-utils: implement the FULLDATA rebuild mode

[Lucas Karpinski <lkarpinski@nvidia.com>]

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_copy_file_range() is used to
leverage the copy_file_range(2) if available. This bypasses userspace
buffering and enables kernel side data transfers.

Verification:
1. Created a source directory containing flat inodes, inline inodes,
   symlinks and absolute symlinks. Verified data integrity by comparing
   checksums of files within the mounted image.
2. Built same image with default rebuild and rebuild with FULLDATA. Then
   ran F-i-f/tdiff comparing the two.

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@nvidia.com>
---
Lucas Karpinski (5):
      erofs-utils: lib: pass uniaddr_offset to erofs_rebuild_load_tree
      erofs-utils: lib: add helper function erofs_uuid_unparse_as_tag
      erofs-utils: lib: preserve primarydevice_blocks if already larger
      erofs-utils: mfks: add rebuild FULLDATA for combined EROFS images
      erofs-utils: manpages: update to reflect fulldata support

 lib/cache.c            |   6 +++
 lib/importer.c         |   5 ++-
 lib/liberofs_cache.h   |   1 +
 lib/liberofs_rebuild.h |   7 ++-
 lib/liberofs_uuid.h    |   1 +
 lib/rebuild.c          | 117 +++++++++++++++++++++++++++++++++++++++++++++++--
 lib/uuid_unparse.c     |  16 ++++++-
 man/mkfs.erofs.1       |   7 ++-
 mkfs/main.c            |  53 ++++++++++++++--------
 9 files changed, 185 insertions(+), 28 deletions(-)
---