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Filename Latest commit message Latest commit date
Li Zhang c25984fa18 btrfs: clear MISSING device status bit in btrfs_close_one_device
commit 5d03dbebba2594d2e6fbf3b5dd9060c5a835de3b upstream.

Reported bug: https://github.com/kdave/btrfs-progs/issues/389

There's a problem with scrub reporting aborted status but returning
error code 0, on a filesystem with missing and readded device.

Roughly these steps:

- mkfs -d raid1 dev1 dev2
- fill with data
- unmount
- make dev1 disappear
- mount -o degraded
- copy more data
- make dev1 appear again

Running scrub afterwards reports that the command was aborted, but the
system log message says the exit code was 0.

It seems that the cause of the error is decrementing
fs_devices->missing_devices but not clearing device->dev_state.  Every
time we umount filesystem, it would call close_ctree, And it would
eventually involve btrfs_close_one_device to close the device, but it
only decrements fs_devices->missing_devices but does not clear the
device BTRFS_DEV_STATE_MISSING bit. Worse, this bug will cause Integer
Overflow, because every time umount, fs_devices->missing_devices will
decrease. If fs_devices->missing_devices value hit 0, it would overflow.

With added debugging:

   loop1: detected capacity change from 0 to 20971520
   BTRFS: device fsid 56ad51f1-5523-463b-8547-c19486c51ebb devid 1 transid 21 /dev/loop1 scanned by systemd-udevd (2311)
   loop2: detected capacity change from 0 to 20971520
   BTRFS: device fsid 56ad51f1-5523-463b-8547-c19486c51ebb devid 2 transid 17 /dev/loop2 scanned by systemd-udevd (2313)
   BTRFS info (device loop1): flagging fs with big metadata feature
   BTRFS info (device loop1): allowing degraded mounts
   BTRFS info (device loop1): using free space tree
   BTRFS info (device loop1): has skinny extents
   BTRFS info (device loop1):  before clear_missing.00000000f706684d /dev/loop1 0
   BTRFS warning (device loop1): devid 2 uuid 6635ac31-56dd-4852-873b-c60f5e2d53d2 is missing
   BTRFS info (device loop1):  before clear_missing.0000000000000000 /dev/loop2 1
   BTRFS info (device loop1): flagging fs with big metadata feature
   BTRFS info (device loop1): allowing degraded mounts
   BTRFS info (device loop1): using free space tree
   BTRFS info (device loop1): has skinny extents
   BTRFS info (device loop1):  before clear_missing.00000000f706684d /dev/loop1 0
   BTRFS warning (device loop1): devid 2 uuid 6635ac31-56dd-4852-873b-c60f5e2d53d2 is missing
   BTRFS info (device loop1):  before clear_missing.0000000000000000 /dev/loop2 0
   BTRFS info (device loop1): flagging fs with big metadata feature
   BTRFS info (device loop1): allowing degraded mounts
   BTRFS info (device loop1): using free space tree
   BTRFS info (device loop1): has skinny extents
   BTRFS info (device loop1):  before clear_missing.00000000f706684d /dev/loop1 18446744073709551615
   BTRFS warning (device loop1): devid 2 uuid 6635ac31-56dd-4852-873b-c60f5e2d53d2 is missing
   BTRFS info (device loop1):  before clear_missing.0000000000000000 /dev/loop2 18446744073709551615

If fs_devices->missing_devices is 0, next time it would be 18446744073709551615

After apply this patch, the fs_devices->missing_devices seems to be
right:

  $ truncate -s 10g test1
  $ truncate -s 10g test2
  $ losetup /dev/loop1 test1
  $ losetup /dev/loop2 test2
  $ mkfs.btrfs -draid1 -mraid1 /dev/loop1 /dev/loop2 -f
  $ losetup -d /dev/loop2
  $ mount -o degraded /dev/loop1 /mnt/1
  $ umount /mnt/1
  $ mount -o degraded /dev/loop1 /mnt/1
  $ umount /mnt/1
  $ mount -o degraded /dev/loop1 /mnt/1
  $ umount /mnt/1
  $ dmesg

   loop1: detected capacity change from 0 to 20971520
   loop2: detected capacity change from 0 to 20971520
   BTRFS: device fsid 15aa1203-98d3-4a66-bcae-ca82f629c2cd devid 1 transid 5 /dev/loop1 scanned by mkfs.btrfs (1863)
   BTRFS: device fsid 15aa1203-98d3-4a66-bcae-ca82f629c2cd devid 2 transid 5 /dev/loop2 scanned by mkfs.btrfs (1863)
   BTRFS info (device loop1): flagging fs with big metadata feature
   BTRFS info (device loop1): allowing degraded mounts
   BTRFS info (device loop1): disk space caching is enabled
   BTRFS info (device loop1): has skinny extents
   BTRFS info (device loop1):  before clear_missing.00000000975bd577 /dev/loop1 0
   BTRFS warning (device loop1): devid 2 uuid 8b333791-0b3f-4f57-b449-1c1ab6b51f38 is missing
   BTRFS info (device loop1):  before clear_missing.0000000000000000 /dev/loop2 1
   BTRFS info (device loop1): checking UUID tree
   BTRFS info (device loop1): flagging fs with big metadata feature
   BTRFS info (device loop1): allowing degraded mounts
   BTRFS info (device loop1): disk space caching is enabled
   BTRFS info (device loop1): has skinny extents
   BTRFS info (device loop1):  before clear_missing.00000000975bd577 /dev/loop1 0
   BTRFS warning (device loop1): devid 2 uuid 8b333791-0b3f-4f57-b449-1c1ab6b51f38 is missing
   BTRFS info (device loop1):  before clear_missing.0000000000000000 /dev/loop2 1
   BTRFS info (device loop1): flagging fs with big metadata feature
   BTRFS info (device loop1): allowing degraded mounts
   BTRFS info (device loop1): disk space caching is enabled
   BTRFS info (device loop1): has skinny extents
   BTRFS info (device loop1):  before clear_missing.00000000975bd577 /dev/loop1 0
   BTRFS warning (device loop1): devid 2 uuid 8b333791-0b3f-4f57-b449-1c1ab6b51f38 is missing
   BTRFS info (device loop1):  before clear_missing.0000000000000000 /dev/loop2 1

CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Li Zhang <zhanglikernel@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-17 09:48:22 +01:00
arch bpf: Define bpf_jit_alloc_exec_limit for arm64 JIT 2021-11-17 09:48:20 +01:00
block Revert "block, bfq: honor already-setup queue merges" 2021-10-06 15:42:34 +02:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: shash - avoid comparing pointers to exported functions under CFI 2021-07-14 16:53:13 +02:00
Documentation dt-bindings: mtd: gpmc: Fix the ECC bytes vs. OOB bytes equation 2021-09-22 12:26:43 +02:00
drivers nfp: bpf: relax prog rejection for mtu check through max_pkt_offset 2021-11-17 09:48:21 +01:00
fs btrfs: clear MISSING device status bit in btrfs_close_one_device 2021-11-17 09:48:22 +01:00
include net: multicast: calculate csum of looped-back and forwarded packets 2021-11-17 09:48:21 +01:00
init kbuild: add CONFIG_LD_IS_LLD 2021-06-30 08:47:44 -04:00
ipc
kernel bpf: Prevent increasing bpf_jit_limit above max 2021-11-17 09:48:20 +01:00
lib Kconfig.debug: drop selecting non-existing HARDLOCKUP_DETECTOR_ARCH 2021-09-26 14:07:10 +02:00
LICENSES
mm mm, slub: fix potential memoryleak in kmem_cache_open() 2021-10-27 09:54:28 +02:00
net net/smc: Correct spelling mistake to TCPF_SYN_RECV 2021-11-17 09:48:22 +01:00
samples samples: bpf: Fix tracex7 error raised on the missing argument 2021-09-22 12:26:30 +02:00
scripts gcc-plugins/structleak: add makefile var for disabling structleak 2021-10-27 09:54:28 +02:00
security binder: use cred instead of task for selinux checks 2021-11-17 09:48:16 +01:00
sound ALSA: timer: Unconditionally unlink slave instances, too 2021-11-17 09:48:19 +01:00
tools perf script: Check session->header.env.arch before using it 2021-11-02 19:46:15 +01:00
usr
virt KVM: do not shrink halt_poll_ns below grow_start 2021-10-09 14:39:50 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.159 2021-11-12 14:43:05 +01:00
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.