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Filename Latest commit message Latest commit date
Filipe Manana 09c826447c btrfs: fix filesystem corruption after a device replace
commit 4c8f353272dd1262013873990c0fafd0e3c8f274 upstream.

We use a device's allocation state tree to track ranges in a device used
for allocated chunks, and we set ranges in this tree when allocating a new
chunk. However after a device replace operation, we were not setting the
allocated ranges in the new device's allocation state tree, so that tree
is empty after a device replace.

This means that a fitrim operation after a device replace will trim the
device ranges that have allocated chunks and extents, as we trim every
range for which there is not a range marked in the device's allocation
state tree. It is also important during chunk allocation, since the
device's allocation state is used to determine if a range is already
allocated when allocating a new chunk.

This is trivial to reproduce and the following script triggers the bug:

  $ cat reproducer.sh
  #!/bin/bash

  DEV1="/dev/sdg"
  DEV2="/dev/sdh"
  DEV3="/dev/sdi"

  wipefs -a $DEV1 $DEV2 $DEV3 &> /dev/null

  # Create a raid1 test fs on 2 devices.
  mkfs.btrfs -f -m raid1 -d raid1 $DEV1 $DEV2 > /dev/null
  mount $DEV1 /mnt/btrfs

  xfs_io -f -c "pwrite -S 0xab 0 10M" /mnt/btrfs/foo

  echo "Starting to replace $DEV1 with $DEV3"
  btrfs replace start -B $DEV1 $DEV3 /mnt/btrfs
  echo

  echo "Running fstrim"
  fstrim /mnt/btrfs
  echo

  echo "Unmounting filesystem"
  umount /mnt/btrfs

  echo "Mounting filesystem in degraded mode using $DEV3 only"
  wipefs -a $DEV1 $DEV2 &> /dev/null
  mount -o degraded $DEV3 /mnt/btrfs
  if [ $? -ne 0 ]; then
          dmesg | tail
          echo
          echo "Failed to mount in degraded mode"
          exit 1
  fi

  echo
  echo "File foo data (expected all bytes = 0xab):"
  od -A d -t x1 /mnt/btrfs/foo

  umount /mnt/btrfs

When running the reproducer:

  $ ./replace-test.sh
  wrote 10485760/10485760 bytes at offset 0
  10 MiB, 2560 ops; 0.0901 sec (110.877 MiB/sec and 28384.5216 ops/sec)
  Starting to replace /dev/sdg with /dev/sdi

  Running fstrim

  Unmounting filesystem
  Mounting filesystem in degraded mode using /dev/sdi only
  mount: /mnt/btrfs: wrong fs type, bad option, bad superblock on /dev/sdi, missing codepage or helper program, or other error.
  [19581.748641] BTRFS info (device sdg): dev_replace from /dev/sdg (devid 1) to /dev/sdi started
  [19581.803842] BTRFS info (device sdg): dev_replace from /dev/sdg (devid 1) to /dev/sdi finished
  [19582.208293] BTRFS info (device sdi): allowing degraded mounts
  [19582.208298] BTRFS info (device sdi): disk space caching is enabled
  [19582.208301] BTRFS info (device sdi): has skinny extents
  [19582.212853] BTRFS warning (device sdi): devid 2 uuid 1f731f47-e1bb-4f00-bfbb-9e5a0cb4ba9f is missing
  [19582.213904] btree_readpage_end_io_hook: 25839 callbacks suppressed
  [19582.213907] BTRFS error (device sdi): bad tree block start, want 30490624 have 0
  [19582.214780] BTRFS warning (device sdi): failed to read root (objectid=7): -5
  [19582.231576] BTRFS error (device sdi): open_ctree failed

  Failed to mount in degraded mode

So fix by setting all allocated ranges in the replace target device when
the replace operation is finishing, when we are holding the chunk mutex
and we can not race with new chunk allocations.

A test case for fstests follows soon.

Fixes: 1c11b63eff ("btrfs: replace pending/pinned chunks lists with io tree")
CC: stable@vger.kernel.org # 5.2+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-07 08:01:23 +02:00
arch KVM: arm64: Assume write fault on S1PTW permission fault on instruction fetch 2020-10-01 13:18:25 +02:00
block block: only call sched requeue_request() for scheduled requests 2020-09-23 12:40:37 +02:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto crypto: af_alg - Work around empty control messages without MSG_MORE 2020-09-03 11:27:05 +02:00
Documentation ata: make qc_prep return ata_completion_errors 2020-10-01 13:18:26 +02:00
drivers ata: sata_mv, avoid trigerrable BUG_ON 2020-10-01 13:18:26 +02:00
fs btrfs: fix filesystem corruption after a device replace 2020-10-07 08:01:23 +02:00
include ata: make qc_prep return ata_completion_errors 2020-10-01 13:18:26 +02:00
init kprobes: tracing/kprobes: Fix to kill kprobes on initmem after boot 2020-10-01 13:18:23 +02:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel kprobes: Fix compiler warning for !CONFIG_KPROBES_ON_FTRACE 2020-10-01 13:18:25 +02:00
lib lib/string.c: implement stpcpy 2020-10-01 13:18:23 +02:00
LICENSES
mm mm/gup: fix gup_fast with dynamic page table folding 2020-10-01 13:18:24 +02:00
net lib80211: fix unmet direct dependendices config warning when !CRYPTO 2020-10-01 13:18:20 +02:00
samples bpf: Fix fds_example SIGSEGV error 2020-08-19 08:16:03 +02:00
scripts checkpatch: fix the usage of capture group ( ... ) 2020-09-09 19:12:37 +02:00
security device_cgroup: Fix RCU list debugging warning 2020-10-01 13:18:13 +02:00
sound ALSA: hda/realtek: Enable front panel headset LED on Lenovo ThinkStation P520 2020-10-01 13:18:22 +02:00
tools objtool: Fix noreturn detection for ignored functions 2020-10-01 13:18:15 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: arm64: Assume write fault on S1PTW permission fault on instruction fetch 2020-10-01 13:18:25 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.69 2020-10-01 13:19:27 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.