It's a known bug with bcache and enabling discard, it was discarding sections containing data it wanted. After a reboot bcache refused to accept the cache data, and of course it was dirty because I'm frankly too stupid to breathe sometimes.
So yes, it's a bcache issue, but that's unresolvable. I'm trying to rescue the btrfs data that it trashed. On Wed, Apr 8, 2015 at 2:27 PM, Cameron Berkenpas <c...@neo-zeon.de> wrote: > Hello, > > I had some luck in the past with btrfs restore using the -r option. I don't > recall how I determined the roots... Maybe I tried random numbers? I was > able to recover nearly all of my data from a bcache related crash from over > a year ago. > > What kind of bcache failure did you see? I've been doing some testing > recently and ran into 2 bcache failures. With both of these failures, I had > a ' bad btree header at bucket' error message (which is entirely different > from the crash I had over a year back). I'm currently trying a different SSD > to see if that alleviates the issue. The error makes me think that it's a > bcache specific issue that's unrelated to btrfs or possibly (in my case) an > issue with the previous SSD. > > Did you encounter this same error? > > With my 2 most recent crashes, I didn't try to recover very hard (or even > try 'btrfs recover; at all) as I've been taking daily backups. I did try > btrfsck, and not only would it fail, it would segfault. > > -Cameron > > > On 04/08/2015 11:07 AM, Dan Merillat wrote: > > Any ideas on where to start with this? I did flush the cache out to > disk before I made changes to the bcache configuration, so there > shouldn't be anything completely missing, just some bits of stale > metadata. If I can get the tools to take the closest match and run > with it it would probably recover nearly everything. > > At worst, is there a way to scan the metadata blocks and rebuild from > found extent-trees? > > > > > On Tue, Apr 7, 2015 at 11:40 PM, Dan Merillat <dan.meril...@gmail.com> > wrote: > > Bcache failures are nasty, because they leave a mix of old and new > data on the disk. In this case, there was very little dirty data, but > of course the tree roots were dirty and out-of-sync. > > fileserver:/usr/src/btrfs-progs# ./btrfs --version > Btrfs v3.18.2 > > kernel version 3.18 > > [ 572.573566] BTRFS info (device bcache0): enabling auto recovery > [ 572.573619] BTRFS info (device bcache0): disk space caching is enabled > [ 574.266055] BTRFS (device bcache0): parent transid verify failed on > 7567956930560 wanted 613690 found 613681 > [ 574.276952] BTRFS (device bcache0): parent transid verify failed on > 7567956930560 wanted 613690 found 613681 > [ 574.277008] BTRFS: failed to read tree root on bcache0 > [ 574.277187] BTRFS (device bcache0): parent transid verify failed on > 7567956930560 wanted 613690 found 613681 > [ 574.277356] BTRFS (device bcache0): parent transid verify failed on > 7567956930560 wanted 613690 found 613681 > [ 574.277398] BTRFS: failed to read tree root on bcache0 > [ 574.285955] BTRFS (device bcache0): parent transid verify failed on > 7567965720576 wanted 613689 found 613694 > [ 574.298741] BTRFS (device bcache0): parent transid verify failed on > 7567965720576 wanted 613689 found 610499 > [ 574.298804] BTRFS: failed to read tree root on bcache0 > [ 575.047079] BTRFS (device bcache0): bad tree block start 0 7567954464768 > [ 575.111495] BTRFS (device bcache0): parent transid verify failed on > 7567954464768 wanted 613688 found 613685 > [ 575.111559] BTRFS: failed to read tree root on bcache0 > [ 575.121749] BTRFS (device bcache0): bad tree block start 0 7567954214912 > [ 575.131803] BTRFS (device bcache0): parent transid verify failed on > 7567954214912 wanted 613687 found 613680 > [ 575.131866] BTRFS: failed to read tree root on bcache0 > [ 575.180101] BTRFS: open_ctree failed > > all the btrfs tools throw up their hands with similar errors: > ileserver:/usr/src/btrfs-progs# btrfs restore /dev/bcache0 -l > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > Ignoring transid failure > Couldn't setup extent tree > Couldn't setup device tree > Could not open root, trying backup super > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > Ignoring transid failure > Couldn't setup extent tree > Couldn't setup device tree > Could not open root, trying backup super > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > Ignoring transid failure > Couldn't setup extent tree > Couldn't setup device tree > Could not open root, trying backup super > > > fileserver:/usr/src/btrfs-progs# ./btrfsck --repair /dev/bcache0 > --init-extent-tree > enabling repair mode > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > Ignoring transid failure > Couldn't setup extent tree > Couldn't setup device tree > Couldn't open file system > > Annoyingly: > # ./btrfs-image -c9 -t4 -s -w /dev/bcache0 /tmp/test.out > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > parent transid verify failed on 7567956930560 wanted 613690 found 613681 > Ignoring transid failure > Couldn't setup extent tree > Open ctree failed > create failed (Success) > > So I can't even send an image for people to look at. > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
