On Wed, Oct 10, 2018 at 10:00 PM, Chris Murphy <li...@colorremedies.com> wrote: > On Wed, Oct 10, 2018 at 9:07 PM, Larkin Lowrey > <llow...@nuclearwinter.com> wrote: >> On 10/10/2018 10:51 PM, Chris Murphy wrote: >>> >>> On Wed, Oct 10, 2018 at 8:12 PM, Larkin Lowrey >>> <llow...@nuclearwinter.com> wrote: >>>> >>>> On 10/10/2018 7:55 PM, Hans van Kranenburg wrote: >>>>> >>>>> On 10/10/2018 07:44 PM, Chris Murphy wrote: >>>>>> >>>>>> >>>>>> I'm pretty sure you have to umount, and then clear the space_cache >>>>>> with 'btrfs check --clear-space-cache=v1' and then do a one time mount >>>>>> with -o space_cache=v2. >>>>> >>>>> The --clear-space-cache=v1 is optional, but recommended, if you are >>>>> someone who do not likes to keep accumulated cruft. >>>>> >>>>> The v2 mount (rw mount!!!) does not remove the v1 cache. If you just >>>>> mount with v2, the v1 data keeps being there, doing nothing any more. >>>> >>>> >>>> Theoretically I have the v2 space_cache enabled. After a clean umount... >>>> >>>> # mount -onospace_cache /backups >>>> [ 391.243175] BTRFS info (device dm-3): disabling free space tree >>>> [ 391.249213] BTRFS error (device dm-3): cannot disable free space tree >>>> [ 391.255884] BTRFS error (device dm-3): open_ctree failed >>> >>> "free space tree" is the v2 space cache, and once enabled it cannot be >>> disabled with nospace_cache mount option. If you want to run with >>> nospace_cache you'll need to clear it. >>> >>> >>>> # mount -ospace_cache=v1 /backups/ >>>> mount: /backups: wrong fs type, bad option, bad superblock on >>>> /dev/mapper/Cached-Backups, missing codepage or helper program, or other >>>> error >>>> [ 983.501874] BTRFS info (device dm-3): enabling disk space caching >>>> [ 983.508052] BTRFS error (device dm-3): cannot disable free space tree >>>> [ 983.514633] BTRFS error (device dm-3): open_ctree failed >>> >>> You cannot go back and forth between v1 and v2. Once v2 is enabled, >>> it's always used regardless of any mount option. You'll need to use >>> btrfs check to clear the v2 cache if you want to use v1 cache. >>> >>> >>>> # btrfs check --clear-space-cache v1 /dev/Cached/Backups >>>> Opening filesystem to check... >>>> couldn't open RDWR because of unsupported option features (3). >>>> ERROR: cannot open file system >>> >>> You're missing the '=' symbol for the clear option, that's why it fails. >>> >> >> # btrfs check --clear-space-cache=v2 /dev/Cached/Backups >> Opening filesystem to check... >> Checking filesystem on /dev/Cached/Backups >> UUID: acff5096-1128-4b24-a15e-4ba04261edc3 >> Clear free space cache v2 >> Segmentation fault (core dumped) >> >> [ 109.686188] btrfs[2429]: segfault at 68 ip 0000555ff6394b1c sp >> 00007ffcc4733ab0 error 4 in btrfs[555ff637c000+ca000] >> [ 109.696732] Code: ff e8 68 ed ff ff 8b 4c 24 58 4d 8b 8f c7 01 00 00 4c >> 89 fe 85 c0 0f 44 44 24 40 45 31 c0 89 44 24 40 48 8b 84 24 90 00 00 00 <8b> >> 40 68 49 29 87 d0 00 00 00 6a 00 55 48 8b 54 24 18 48 8b 7c 24 >> >> That's btrfs-progs v4.17.1 on 4.18.12-200.fc28.x86_64. >> >> I appreciate the help and advice from everyone who has contributed to this >> thread. At this point, unless there is something for the project to gain >> from tracking down this trouble, I'm just going to nuke the fs and start >> over. > > Is this a 68T file system? Seems excessive.
Haha, by excessive I mean nuking such a big fs just for being unable to remove the space tree. I'm quite sure the devs would like to get that crashing bug fixed, anyway. -- Chris Murphy
