I'm going to fill in some details from the multiday conversation with IRC regulars. We couldn't figure out a way forward.
* WDC Red with Firmware Version: 80.00A80, which is highly suspected to deal with power fail and write caching incorrectly, and at least on Btrfs apparently pretty much always drops writes for critical metadata. * A power fail / reset happened * No snapshots * --repair and --init-extent-tree may not have done anything because they didn't complete * Less than 10% needs to be recovered and it's accepted that it can't be repaired. The focus is just on a limited restore, but we can't get past the transid failures. zapan@UBUNTU-SERVER:~$ sudo btrfs check --readonly /dev/md0 Opening filesystem to check... parent transid verify failed on 23079040831488 wanted 524940 found 524941 parent transid verify failed on 23079040831488 wanted 524940 found 524941 Ignoring transid failure parent transid verify failed on 23079040319488 wanted 524931 found 524939 Ignoring transid failure Checking filesystem on /dev/md0 UUID: f4f04e16-ce38-4a57-8434-67562a0790bd [1/7] checking root items parent transid verify failed on 23079042863104 wanted 423153 found 524931 parent transid verify failed on 23079042863104 wanted 423153 found 524931 Ignoring transid failure ERROR: child eb corrupted: parent bytenr=23079040999424 item=11 parent level=2 child bytenr=23079042863104 child level=0 ERROR: failed to repair root items: Input/output error [2/7] checking extents parent transid verify failed on 23079042863104 wanted 423153 found 524931 Ignoring transid failure ERROR: child eb corrupted: parent bytenr=23079040999424 item=11 parent level=2 child bytenr=23079042863104 child level=0 ERROR: errors found in extent allocation tree or chunk allocation [3/7] checking free space cache cache and super generation don't match, space cache will be invalidated [4/7] checking fs roots root 5 root dir 256 not found parent transid verify failed on 23079042863104 wanted 423153 found 524931 Ignoring transid failure ERROR: child eb corrupted: parent bytenr=23079040999424 item=11 parent level=2 child bytenr=23079042863104 child level=0 ERROR: errors found in fs roots found 0 bytes used, error(s) found total csum bytes: 0 total tree bytes: 0 total fs tree bytes: 0 total extent tree bytes: 0 btree space waste bytes: 0 file data blocks allocated: 0 referenced 0 btrfs-find-root doesn't find many options to work with, and all of them fail with 'btrfs restore -t' zapan@UBUNTU-SERVER:~$ sudo btrfs-find-root /dev/md0 parent transid verify failed on 23079040831488 wanted 524940 found 524941 parent transid verify failed on 23079040831488 wanted 524940 found 524941 Ignoring transid failure parent transid verify failed on 23079040319488 wanted 524931 found 524939 Ignoring transid failure Superblock thinks the generation is 524941 Superblock thinks the level is 2 Found tree root at 23079040999424 gen 524941 level 2 Well block 23079040327680(gen: 524940 level: 2) seems good, but generation/level doesn't match, want gen: 524941 level: 2 Well block 23079040389120(gen: 524939 level: 2) seems good, but generation/level doesn't match, want gen: 524941 level: 2 zapan@UBUNTU-SERVER:~$ sudo btrfs restore -viD -t 23079040389120 /dev/md0 /mnt/raid1/restore/ parent transid verify failed on 23079040389120 wanted 524941 found 524939 parent transid verify failed on 23079040389120 wanted 524941 found 524939 Ignoring transid failure parent transid verify failed on 23079040323584 wanted 524939 found 524941 parent transid verify failed on 23079040323584 wanted 524939 found 524941 Ignoring transid failure parent transid verify failed on 23079040319488 wanted 524931 found 524939 Ignoring transid failure This is a dry-run, no files are going to be restored Reached the end of the tree searching the directory zapan@UBUNTU-SERVER:~$ sudo btrfs restore -viD -t 23079040327680 /dev/md0 /mnt/raid1/restore/ parent transid verify failed on 23079040327680 wanted 524941 found 524940 parent transid verify failed on 23079040327680 wanted 524941 found 524940 Ignoring transid failure parent transid verify failed on 23079040831488 wanted 524940 found 524941 parent transid verify failed on 23079040831488 wanted 524940 found 524941 Ignoring transid failure parent transid verify failed on 23079040319488 wanted 524931 found 524939 Ignoring transid failure This is a dry-run, no files are going to be restored Reached the end of the tree searching the directory -- Chris Murphy
