On 23.06.20 г. 5:09 ч., Russell Coker wrote: > [395198.926320] BTRFS warning (device sdc1): csum failed root 5 ino 276 off > 19267584 csum 0x8941f998 expected csum 0xccd545e0 mirror 1 > [395199.147439] BTRFS warning (device sdc1): csum failed root 5 ino 276 off > 20611072 csum 0x8941f998 expected csum 0xdaf657cb mirror 1 > [395199.183680] BTRFS warning (device sdc1): csum failed root 5 ino 276 off > 24190976 csum 0x8941f998 expected csum 0xcddce0b1 mirror 1 > [395199.185172] BTRFS warning (device sdc1): csum failed root 5 ino 276 off > 19267584 csum 0x8941f998 expected csum 0xccd545e0 mirror 1 > [395199.330841] BTRFS warning (device sdc1): csum failed root 5 ino 277 off 0 > csum 0x8941f998 expected csum 0xa54d865c mirror 1 > > I have a USB stick that's corrupted, I get the above kernel messages when I > try to copy files from it. But according to btrfs dev sta it has had 0 read > and 0 corruption errors. > > root@xev:/mnt/tmp# btrfs dev sta . > [/dev/sdc1].write_io_errs 0 > [/dev/sdc1].read_io_errs 0 > [/dev/sdc1].flush_io_errs 0 > [/dev/sdc1].corruption_errs 0 > [/dev/sdc1].generation_errs 0 > root@xev:/mnt/tmp# uname -a > Linux xev 5.6.0-2-amd64 #1 SMP Debian 5.6.14-1 (2020-05-23) x86_64 GNU/Linux > The read/write io err counters are updated when even repair bio have failed. So in your case you had some checksum errors, but btrfs managed to repair them by reading from a different mirror. In this case those aren't really counted as io errs since in the end you did get the correct data.
