I was attempting to replace the drives in an array with RAID6 profile. The first replacement was seemingly successful (and there was a scrub afterward, with no errors). However, about 0.6% into the second replacement (sdc), something went wrong, and it went read-only (I should have copied the log of that somehow). Now it refuses to mount, and a (readonly) check cannot get started.
# mount -o ro,degraded /dev/sda3 /mnt mount: /mnt: can't read superblock on /dev/sda3. # btrfs rescue super-recover /dev/sda3 All supers are valid, no need to recover For this, dmesg shows: [ 202.675384] BTRFS info (device sdc3): allowing degraded mounts [ 202.675387] BTRFS info (device sdc3): disk space caching is enabled [ 202.675389] BTRFS info (device sdc3): has skinny extents [ 202.676302] BTRFS warning (device sdc3): devid 3 uuid 911a642e-0a4c-4483-9a1f-cde7b87c5519 is missing [ 202.676601] BTRFS warning (device sdc3): devid 3 uuid 911a642e-0a4c-4483-9a1f-cde7b87c5519 is missing [ 202.985528] BTRFS info (device sdc3): bdev /dev/sdb3 errs: wr 0, rd 0, flush 0, corrupt 26, gen 0 [ 202.985533] BTRFS info (device sdc3): bdev /dev/sdd3 errs: wr 0, rd 0, flush 0, corrupt 98, gen 0 [ 203.278131] BTRFS info (device sdc3): start tree-log replay [ 203.454496] BTRFS critical (device sdc3): corrupt leaf: root=7 block=371567214592 slot=0, unexpected item end, have 16315 expect 16283 [ 203.454499] BTRFS error (device sdc3): block=371567214592 read time tree block corruption detected [ 203.454634] BTRFS critical (device sdc3): corrupt leaf: root=7 block=371567214592 slot=0, unexpected item end, have 16315 expect 16283 [ 203.454636] BTRFS error (device sdc3): block=371567214592 read time tree block corruption detected [ 203.455794] BTRFS critical (device sdc3): corrupt leaf: root=7 block=371567214592 slot=0, unexpected item end, have 16315 expect 16283 [ 203.455796] BTRFS error (device sdc3): block=371567214592 read time tree block corruption detected [ 203.455820] BTRFS: error (device sdc3) in __btrfs_free_extent:3105: errno=-5 IO failure [ 203.455823] BTRFS: error (device sdc3) in btrfs_run_delayed_refs:2208: errno=-5 IO failure [ 203.455833] BTRFS: error (device sdc3) in btrfs_replay_log:2287: errno=-5 IO failure (Failed to recover log tree) [ 203.747758] BTRFS error (device sdc3): open_ctree failed I've looked for, but can't find, any bad blocks on the devices. Also, if it adds any info... # btrfs check --readonly /dev/sda3 Opening filesystem to check... warning, device 3 is missing checksum verify failed on 371587727360 found 000000FF wanted 00000049 checksum verify failed on 371587727360 found 00000005 wanted 00000010 checksum verify failed on 371587727360 found 00000005 wanted 00000010 bad tree block 371587727360, bytenr mismatch, want=371587727360, have=1076190010624 ERROR: could not setup extent tree ERROR: cannot open file system Note: I'm running this off of System Rescue 7.01, which has earlier versions of things than what the machine in question has installed (the latter being Linux 5.10.16, with btrfs-progs v5.10.1). # uname -a Linux sysrescue 5.4.78-1-lts #1 SMP Wed, 18 Nov 2020 19:51:49 +0000 x86_64 GNU/Linux # btrfs --version btrfs-progs v5.4.1 # btrfs filesystem show Label: 'vroot2020' uuid: 5214d903-783a-4d14-ac78-046da5ac1db7 Total devices 4 FS bytes used 65.98GiB devid 0 size 457.64GiB used 39.53GiB path /dev/sdc3 devid 1 size 457.64GiB used 39.56GiB path /dev/sda3 devid 2 size 457.64GiB used 39.56GiB path /dev/sdb3 devid 4 size 457.64GiB used 39.53GiB path /dev/sdd3 -- Skype: fllthdcrb PGP public key: 0xF7B4422A PGP fingerprint: 5BBD 5080 FEB0 EF7F 142F 8173 D572 B791 F7B4 422A
