Hi, Just noticed that one of my btrfs mounts on a server was in read-only mode.
dmesg shows: [2217355.427810] BTRFS info (device sda3): scrub: started on devid 1 [2221262.216646] BTRFS info (device sda3): scrub: finished on devid 1 with status: 0 [2390153.679168] BTRFS info (device sda4): scrub: started on devid 1 [2393339.627095] BTRFS info (device sda4): scrub: finished on devid 1 with status: 0 [2555511.868642] BTRFS critical (device sda4): corrupt leaf: root=258 block=250975895552 slot=78, bad key order, prev (256703 108 3276800) current (256703 108 1310720) [2555511.868650] BTRFS error (device sda4): block=250975895552 write time tree block corruption detected [2555511.916529] BTRFS: error (device sda4) in btrfs_commit_transaction:2279: errno=-5 IO failure (Error while writing out transaction) [2555511.916544] BTRFS info (device sda4): forced readonly [2555511.916547] BTRFS warning (device sda4): Skipping commit of aborted transaction. [2555511.916551] BTRFS: error (device sda4) in cleanup_transaction:1832: errno=-5 IO failure [2555511.916560] BTRFS info (device sda4): delayed_refs has NO entry [2555511.916687] BTRFS info (device sda4): delayed_refs has NO entry Running "btrfs check" shows no further issues: sudo btrfs check --force --readonly /dev/sda4 Opening filesystem to check... WARNING: filesystem mounted, continuing because of --force Checking filesystem on /dev/sda4 UUID: 72deb54c-96dd-42cf-a809-bef1a135f409 [1/7] checking root items [2/7] checking extents [3/7] checking free space cache [4/7] checking fs roots [5/7] checking only csums items (without verifying data) [6/7] checking root refs [7/7] checking quota groups skipped (not enabled on this FS) found 242436075520 bytes used, no error found total csum bytes: 235186808 total tree bytes: 961773568 total fs tree bytes: 665829376 total extent tree bytes: 43728896 btree space waste bytes: 122086726 file data blocks allocated: 447700926464 referenced 257665265664 Kernel: Linux amd8 5.4.0-65-generic #73-Ubuntu SMP Mon Jan 18 17:25:17 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux Can someone help me to pinpoint the cause of this issue and prevent it from happening again? If more info is needed from my side, please let me know. Cheers, chill
