Re: Massive filesystem corruption since kernel 5.2 (ARCH)

["Swâmi Petaramesh" <swami@petaramesh.org>]

Hi again,

Le 27/08/2019 à 08:21, Qu Wenruo a écrit :
> I'd prefer to do a "btrfs check --readonly" anyway (which also checks
> free space cache), then go nospace_cache if you're concerned.

Here's what I dit, here's what I got...:

root@PartedMagic:~# uname -r
5.1.5-pmagic64

root@PartedMagic:~# btrfs --version
btrfs-progs v5.1

root@PartedMagic:~# btrfs check --readonly /dev/PPL_VG1/LINUX
[1/7] checking root items
[2/7] checking extents
[3/7] checking free space cache
block group 52677312512 has wrong amount of free space, free space cache
has 266551296 block group has 266584064
failed to load free space cache for block group 52677312512
[4/7] checking fs roots
[5/7] checking only csums items (without verifying data)
[6/7] checking root refs
[7/7] checking quota groups skipped (not enabled on this FS)
Opening filesystem to check...
Checking filesystem on /dev/PPL_VG1/LINUX
UUID: 25fede5a-d8c2-4c7e-9e7e-b19aad319044
found 87804731392 bytes used, no error found
total csum bytes: 79811080
total tree bytes: 2195832832
total fs tree bytes: 1992900608
total extent tree bytes: 101548032
btree space waste bytes: 380803707
file data blocks allocated: 626135830528
 referenced 124465221632

root@PartedMagic:~# mkdir /hd
root@PartedMagic:~# mount -t btrfs -o noatime,clear_cache
/dev/PPL_VG1/LINUX /hd

(Waited for no disk activity and top showing no btrfs processes)

root@PartedMagic:~# umount /hd

root@PartedMagic:~# mount -t btrfs -o noatime /dev/PPL_VG1/LINUX /hd

root@PartedMagic:~# grep btrfs /proc/self/mountinfo
40 31 0:43 / /hd rw,noatime - btrfs /dev/mapper/PPL_VG1-LINUX
rw,ssd,space_cache,subvolid=5,subvol=/

root@PartedMagic:~# umount /hd

root@PartedMagic:~# btrfs check --readonly /dev/PPL_VG1/LINUX
[1/7] checking root items
[2/7] checking extents
[3/7] checking free space cache
block group 52677312512 has wrong amount of free space, free space cache
has 266551296 block group has 266584064
failed to load free space cache for block group 52677312512
[4/7] checking fs roots
[5/7] checking only csums items (without verifying data)
[6/7] checking root refs
[7/7] checking quota groups skipped (not enabled on this FS)
Opening filesystem to check...
Checking filesystem on /dev/PPL_VG1/LINUX
UUID: 25fede5a-d8c2-4c7e-9e7e-b19aad319044
found 87804207104 bytes used, no error found
total csum bytes: 79811080
total tree bytes: 2195832832
total fs tree bytes: 1992900608
total extent tree bytes: 101548032
btree space waste bytes: 380804019
file data blocks allocated: 626135306240
 referenced 124464697344
root@PartedMagic:~#


So it seems that mounting with “clear_cache” did not actually clear the
cache and fix the issue ?

ॐ

-- 
Swâmi Petaramesh <swami@petaramesh.org> PGP 9076E32E