[f2fs-dev] [PATCH v2 0/4] fsck: Check write pointers of zoned block devices

[Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>]

On sudden f2fs shutdown, zoned block device status and f2fs meta data can be
inconsistent. When f2fs shutdown happens during write operations, write pointers
on the device go forward but the f2fs meta data does not reflect write pointer
progress. This inconsistency will eventually cause "Unaligned write command"
error when restarting write operation after the next mount. This error can be
observed with xfstests test case generic/388, which enforces sudden shutdown
during write operation and checks the file system recovery. Once the error
happens because of the inconsistency, the file system requires fix. However,
fsck.f2fs does not have a feature to check and fix it.

This patch series adds a new feature to fsck.f2fs to check and fix the
inconsistency. First and second patches add two functions which helps fsck to
call report zone and reset zone commands to zoned block devices. Third patch
checks write pointers of zones that current segments recorded in meta data point
to. This covers the failure symptom observed with xfstests. The last patch
checks write pointers of zones that current segments do not point to, which
covers a potential failure scenario.

This patch series depends on other patches for zoned block devices, then it
conflicts with the master branch in f2fs-tools.git as of Aug/19/2019. It can be
applied without conflict to dev and dev-test branch tips.

Changes from v1:
* Fixed build failure on dev branch

Shin'ichiro Kawasaki (4):
  libf2fs_zoned: Introduce f2fs_report_zones() helper function
  libf2fs_zoned: Introduce f2fs_reset_zone() function
  fsck.f2fs: Check write pointer consistency with current segments
  fsck.f2fs: Check write pointer consistency with valid blocks count

 fsck/fsck.c         | 161 ++++++++++++++++++++++++++++++++++++++++++++
 fsck/fsck.h         |   3 +
 fsck/main.c         |   2 +
 include/f2fs_fs.h   |   3 +
 lib/libf2fs_zoned.c |  81 ++++++++++++++++++++++
 5 files changed, 250 insertions(+)

-- 
2.21.0



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