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From: Shin'ichiro Kawasaki <>
To: Jaegeuk Kim <>, Chao Yu <>,
Cc: Damien Le Moal <>
Subject: [f2fs-dev] [PATCH v6 0/2] f2fs: Check write pointers of zoned block devices
Date: Wed, 15 Jan 2020 11:25:07 +0900
Message-ID: <> (raw)

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 the write
pointer progress. This inconsistency will eventually cause "Unaligned write
command" error when restarting write operation after the next mount.

This error is observed with xfstests test case generic/388, which enforces
sudden shutdown during write operation and checks the file system recovery.

This patch series adds a feature to f2fs to check and fix the write pointer
consistency when zoned block devices get mounted. Per discussion on the list,
implement two checks: a check for open zones and a check for non-open zones.
The first patch add the check for open zones that current segments point to.
Check write pointer consistency with current segment positions recorded in CP,
and if they are inconsistent, assign a new zone to the current segment. When
fsync data exists, check and fix the consistency after fsync data recovery.

The second patch adds the check for non-open zones that current segments do not
point to. Compare write pointers with valid block maps in SIT, and if they are
inconsistent, report the failure or fix by resetting the write pointer.

Thank goes to Chao Yu for the detailed discussion on the list.

Changes from v5:
* Removed unused variable cs_block that YueHaibing pointed out

Changes from v4:
* Replaced blkdev_zone_mgmt() function calls with __f2fs_issue_discard_zone()

Changes from v3:
* Rebased to linux master tip and fixed conflicts for blkdev_report_zones()
* Discard zones with write pointers not at zone start but without valid blocks,
  resetting the write pointers instead of fsck run by users
* Improved readability of open-zone's check condition and indent with tab

Changes from v2:
* 1st patch: Fix write pointer in SBI_POR_DOING guard
             Removed __set_inuse() and f2fs_stop_checkpoint()
* 2nd patch: Reversed bitmap search and removed __set_inuse()
             Changed condition for disable_roll_forward/norecovery mount options

Changes from v1:
* 2nd patch: Added check to ensure zones are in main segments

Shin'ichiro Kawasaki (2):
  f2fs: Check write pointer consistency of open zones
  f2fs: Check write pointer consistency of non-open zones

 fs/f2fs/f2fs.h     |   2 +
 fs/f2fs/recovery.c |  20 +++-
 fs/f2fs/segment.c  | 257 +++++++++++++++++++++++++++++++++++++++++++++
 fs/f2fs/super.c    |  11 ++
 4 files changed, 288 insertions(+), 2 deletions(-)


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Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-15  2:25 Shin'ichiro Kawasaki [this message]
2020-01-15  2:25 ` [f2fs-dev] [PATCH v6 1/2] f2fs: Check write pointer consistency of open zones Shin'ichiro Kawasaki
2020-01-15  2:25 ` [f2fs-dev] [PATCH v6 2/2] f2fs: Check write pointer consistency of non-open zones Shin'ichiro Kawasaki

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