[PATCH 0/3] btrfs-progs: check: properly fix missing INODE_REF cases

[Qu Wenruo <wqu@suse.com>]

This is inspired by a recent corruption report that an INODE_REF key hits a
bitflip and becomes UNKNOWN.8 key.

That cause missing INODE_REF, and unfortunately neither original nor
lowmem mode can properly handle it.

For the original mode it just completely lacks the handling for such
case, thus fallback to delete the good DIR_INDEX, making things
worse.

For the lowmem mode, although it is trying to keep the good
DIR_INDEX/DIR_ITEM, it doesn't handle index number search, thus using
the default (-1) as index, causing incorrect new link to be added.

Fix both modes, and add a new test case for it.

Qu Wenruo (3):
  btrfs-progs: check/original: add dedicated missing INODE_REF repair
  btrfs-progs: check/lowmem: fix INODE_REF repair
  btrfs-progs: fsck-tests: add a test case for repairing missing
    INODE_REF

 check/main.c                                  |  51 ++++++++++++++++++
 check/mode-lowmem.c                           |  11 ++++
 .../070-missing-inode-ref/.lowmem_repairable  |   0
 .../070-missing-inode-ref/default.img.xz      | Bin 0 -> 2092 bytes
 4 files changed, 62 insertions(+)
 create mode 100644 tests/fsck-tests/070-missing-inode-ref/.lowmem_repairable
 create mode 100644 tests/fsck-tests/070-missing-inode-ref/default.img.xz

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2.52.0