Hey btrfs gurus, I have a 4 disk btrfs filesystem that has suddenly stopped mounting after a recent reboot. The data is in an odd configuration due to originally being in a 3 disk RAID1 before adding a 4th disk and running a balance to convert to RAID10. There wasn't enough free space to completely convert, so about half the data is still in RAID1 while the other half is in RAID10. Both metadata and system are RAID10. It has been in this configuration for 6 months or so now since adding the 4th disk. It just holds archived media and hasn't had any data added or modified in quite some time. I feel pretty stupid now for not correcting that sooner though.
I have tried mounting with different mount options for recovery, ro, degraded, etc. Log shows errors about "unable to find logical 3746892939264 length 4096" When I do a btrfs check, it doesn't find any issues. Running btrfs-find-root comes up with a message about a block that the generation doesn't match. If I specify that block on the btrfs check, I get transid verify failures. I ran a dry run of a recovery of the entire filesystem which runs through every file with no errors. I would just restore the data and start fresh, but unfortunately I don't have the free space at the moment for the ~4.5TB of data. I also ran full smart self tests on all 4 disks with no errors. root@nas2:~# uname -a Linux nas2 4.13.7-041307-generic #201710141430 SMP Sat Oct 14 14:39:06 UTC 2017 i686 i686 i686 GNU/Linux root@nas2:~# btrfs version btrfs-progs v4.13.2 root@nas2:~# btrfs fi show Label: none uuid: 827029a4-8625-4a50-a22d-0fd28dbe2d36 Total devices 4 FS bytes used 4.60TiB devid 1 size 2.73TiB used 2.33TiB path /dev/sdb1 devid 2 size 2.73TiB used 2.33TiB path /dev/sdc devid 3 size 2.73TiB used 2.33TiB path /dev/sdd1 devid 4 size 2.73TiB used 2.33TiB path /dev/sde1 root@nas2:~# mount /dev/sdb1 /mnt/nas2/ mount: wrong fs type, bad option, bad superblock on /dev/sdb1, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so. root@nas2:~# dmesg | tail [ 801.332623] BTRFS info (device sdb1): disk space caching is enabled [ 801.332627] BTRFS info (device sdb1): has skinny extents [ 801.333386] BTRFS critical (device sdb1): unable to find logical 3746892939264 length 4096 [ 801.333472] BTRFS critical (device sdb1): unable to find logical 3746892939264 length 4096 [ 801.333769] BTRFS critical (device sdb1): unable to find logical 3746892939264 length 4096 [ 801.333835] BTRFS critical (device sdb1): unable to find logical 3746892939264 length 4096 [ 801.333909] BTRFS critical (device sdb1): unable to find logical 3746892939264 length 4096 [ 801.333968] BTRFS critical (device sdb1): unable to find logical 3746892939264 length 4096 [ 801.334028] BTRFS error (device sdb1): failed to read chunk root [ 801.365452] BTRFS error (device sdb1): open_ctree failed root@nas2:~# btrfs check /dev/sdb1 Checking filesystem on /dev/sdb1 UUID: 827029a4-8625-4a50-a22d-0fd28dbe2d36 checking extents checking free space cache cache and super generation don't match, space cache will be invalidated checking fs roots checking csums checking root refs found 5054297628672 bytes used, no error found total csum bytes: 4929567064 total tree bytes: 5197856768 total fs tree bytes: 15237120 total extent tree bytes: 43433984 btree space waste bytes: 161510789 file data blocks allocated: 5050024812544 referenced 5049610178560 root@nas2:~# btrfs-find-root /dev/sdb1 Superblock thinks the generation is 147970 Superblock thinks the level is 1 Found tree root at 21335861559296 gen 147970 level 1 Well block 21335857758208(gen: 147969 level: 1) seems good, but generation/level doesn't match, want gen: 147970 level: 1 root@nas2:~# btrfs check -r 21335857758208 /dev/sdb1 parent transid verify failed on 21335857758208 wanted 147970 found 147969 parent transid verify failed on 21335857758208 wanted 147970 found 147969 parent transid verify failed on 21335857758208 wanted 147970 found 147969 parent transid verify failed on 21335857758208 wanted 147970 found 147969 Ignoring transid failure Checking filesystem on /dev/sdb1 UUID: 827029a4-8625-4a50-a22d-0fd28dbe2d36 checking extents checking free space cache cache and super generation don't match, space cache will be invalidated checking fs roots checking csums checking root refs ERROR: transid errors in file system found 5054297628672 bytes used, error(s) found total csum bytes: 4929567064 total tree bytes: 5197856768 total fs tree bytes: 15237120 total extent tree bytes: 43433984 btree space waste bytes: 161510789 file data blocks allocated: 5050024812544 referenced 5049610178560 -- 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
