[PATCH 0/4] btrfs-progs: mkfs/rootdir: cleanup and new fiemap based prealloc detection

[Qu Wenruo <wqu@suse.com>]

The PR can be found here:

  https://github.com/kdave/btrfs-progs/pull/1103

Although previously I added a SEEK_DATA/SEEK_HOLE based hole detection,
it doesn't distinguish holes from preallocated ranges.
Thus if a rootdir contains some preallocated extents and the end user
also expects such preallocated space in the target fs, they will be
replaced by holes.

The 3rd patch adds such detection using fiemap, which can also detect
holes.
For preallocated space we now can create reserved data extent without
data checksum.

The first two patches are mostly cleanups, to disentangle the complex
add_file_item_extent() function, so that compressed fall back is more
straightforward.

The last patch is a simple functional test for the new fiemap feature.

Qu Wenruo (4):
  btrfs-progs: mkfs/rootdir: use a helper to read from source fs
  btrfs-progs: mkfs/rootdir: extract compressed write path
  btrfs-progs: mkfs/rootdir: use fiemap to do prealloc detection
  btrfs-progs: mkfs-tests: add a new test case for fiemap based
    detection

 kernel-shared/file-item.h                     |   3 -
 mkfs/rootdir.c                                | 400 ++++++++++++------
 tests/mkfs-tests/042-fiemap-detection/test.sh |  76 ++++
 3 files changed, 348 insertions(+), 131 deletions(-)
 create mode 100755 tests/mkfs-tests/042-fiemap-detection/test.sh

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2.53.0