[PATCH v2 0/6] Btrfs-progs: rescue: To fix device related

[Qu Wenruo <wqu@suse.com>]

The patchset can be fetched from github:
https://github.com/adam900710/btrfs-progs/tree/check_unaligned_dev

There are several reports in mail list for btrfs device size related
problems.

1) kernel refuse to mount some fs, due to mismatched super total_bytes
   Unmountable if super total_bytes is smaller than total rw bytes of
   all devices.
   Root cause seems to be that, at least for kernel v4.13, some
   device resize/add operation on unaligned device can lead to super
   size out of sync with device size.
   And normally this will cause super size to be 1 page (4096) smaller
   than all devices' size.

   This patchset provides the tool to fix it offline.
   (At least better than unmountable forever)

2) Harmless kernel warning for btrfs_update_device()
   v4.14 introduced restrict device size checker.
   This is causing harmless but annoying kernel warnning.

   It can be fixed online with "btrfs filesystem resize".

   This patchset also provide a fallback method to fix it.

Finally, fix a typo which makes "btrfs rescue zero-log" to continue
execution even the fs is mounted and error message outputted.

Changelog:
v2:
  Move the command line tool from "btrfs check" to "btrfs rescue",
  suggested by David. Although fsck can still repair/detect it.
  Function naming change for cmds-check.c part, suggested by Nikolay.
  Remove inaccurate kernel version, suggested by Nikolay.
  Fix a bug when coding in cmds-rescue.c.
  Split the first patch to make review easier.

Qu Wenruo (6):
  btrfs-progs: Introduce function to fix unaligned device size
  btrfs-progs: Introduce function to fix super block total bytes
  btrfs-progs: rescue: Introduce fix-device-size
  btrfs-progs: check: Also check and repair unalignment/mismatch device
    and super size
  btrfs-progs: test/fsck: Add test case image for --fix-dev-size
  btrfs-progs: rescue: Fix zero-log mounted branch

 Documentation/btrfs-rescue.asciidoc                |  29 ++++
 cmds-check.c                                       |  76 +++++++++
 cmds-rescue.c                                      |  49 ++++++
 .../dev_and_super_mismatch_unaligned.raw.xz        | Bin 0 -> 21536 bytes
 volumes.c                                          | 178 +++++++++++++++++++++
 volumes.h                                          |   4 +
 6 files changed, 336 insertions(+)
 create mode 100644 tests/fsck-tests/027-unaligned-super-dev-sizes/dev_and_super_mismatch_unaligned.raw.xz

-- 
2.14.2