[PATCH RFC 00/17] ubifs: Add filesystem repair support

[Zhihao Cheng]

UBIFS repair provides a way to fix inconsistent UBIFS image(which is
corrupted by hardware exceptions or UBIFS realization bugs) and makes
filesystem become consistent, just like fsck tools(eg. fsck.ext4,
fsck.f2fs, fsck.fat, etc.) do.

About why do we need it, how it works, what it can fix or it can not
fix, when and how to use it, see more details in
Documentation/filesystems/ubifs/repair.rst (Patch 17).

Testing on UBIFS repair refers to
https://bugzilla.kernel.org/show_bug.cgi?id=218327

Whatever, we finally have a way to fix inconsistent UBFIS image instead
of formatting UBI when UBIFS becomes inconsistent.

Zhihao Cheng (17):
  ubifs: repair: Load filesystem info from volume
  ubifs: repair: Scan nodes from volume
  ubifs: repair: Remove deleted nodes from valid node tree
  ubifs: repair: Add valid nodes into file
  ubifs: repair: Filter invalid files
  ubifs: repair: Extract reachable directory entries tree
  ubifs: repair: Check and correct files' information
  ubifs: repair: Record used LEBs
  ubifs: repair: Re-write data
  ubifs: repair: Create new root dir if there are no scanned files
  ubifs: repair: Build TNC
  ubifs: Extract a helper function to create lpt
  ubifs: repair: Build LPT
  ubifs: repair: Clean up log and orphan area
  ubifs: repair: Write master node
  ubifs: Enable ubifs_repair in '/sys/kernel/debug/ubifs/repair_fs'
  Documentation: ubifs: Add ubifs repair whitepaper

 Documentation/filesystems/index.rst           |    3 +-
 .../authentication.rst}                       |    0
 Documentation/filesystems/ubifs/index.rst     |   11 +
 .../filesystems/{ubifs.rst => ubifs/main.rst} |    0
 Documentation/filesystems/ubifs/repair.rst    |  235 ++
 MAINTAINERS                                   |    5 +-
 fs/ubifs/Makefile                             |    2 +-
 fs/ubifs/debug.c                              |   57 +-
 fs/ubifs/debug.h                              |    2 +
 fs/ubifs/journal.c                            |   39 +-
 fs/ubifs/lpt.c                                |  140 +-
 fs/ubifs/repair.c                             | 2651 +++++++++++++++++
 fs/ubifs/repair.h                             |  176 ++
 fs/ubifs/sb.c                                 |   24 +-
 fs/ubifs/super.c                              |   10 +-
 fs/ubifs/ubifs.h                              |  113 +-
 16 files changed, 3315 insertions(+), 153 deletions(-)
 rename Documentation/filesystems/{ubifs-authentication.rst => ubifs/authentication.rst} (100%)
 create mode 100644 Documentation/filesystems/ubifs/index.rst
 rename Documentation/filesystems/{ubifs.rst => ubifs/main.rst} (100%)
 create mode 100644 Documentation/filesystems/ubifs/repair.rst
 create mode 100644 fs/ubifs/repair.c
 create mode 100644 fs/ubifs/repair.h

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2.31.1