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From: Zak Kohler Date: Tue, 24 Oct 2017 02:00:49 -0400 Message-ID: Subject: Re: btrfs send yields "ERROR: send ioctl failed with -5: Input/output error" To: "Lakshmipathi.G" Cc: btrfs Content-Type: text/plain; charset="UTF-8" Sender: linux-btrfs-owner@vger.kernel.org List-ID: Yes, it is finding much more than just one error. >>From dmesg [89520.441354] BTRFS warning (device sdn): csum failed ino 4708 off 27529216 csum 2615801759 expected csum 874979996 $ sudo btrfs scrub start --offline --progress /dev/sdn ERROR: data at bytenr 68431499264 mirror 1 csum mismatch, have 0x5aa0d40f expect 0xd4a15873 ERROR: extent 68431474688 len 14467072 CORRUPTED, all mirror(s) corrupted, can't be repaired ERROR: data at bytenr 83646357504 mirror 1 csum mismatch, have 0xfc0baabe expect 0x7f9cb681 ERROR: extent 83519741952 len 134217728 CORRUPTED, all mirror(s) corrupted, can't be repaired ERROR: data at bytenr 121936633856 mirror 1 csum mismatch, have 0x507016a5 expect 0x50609afe ERROR: extent 121858334720 len 134217728 CORRUPTED, all mirror(s) corrupted, can't be repaired ERROR: data at bytenr 144872591360 mirror 1 csum mismatch, have 0x33964d73 expect 0xf9937032 ERROR: extent 144822386688 len 61231104 CORRUPTED, all mirror(s) corrupted, can't be repaired ERROR: data at bytenr 167961075712 mirror 1 csum mismatch, have 0xf43bd0e3 expect 0x5be589bb ERROR: extent 167950999552 len 27537408 CORRUPTED, all mirror(s) corrupted, can't be repaired ERROR: data at bytenr 175643619328 mirror 1 csum mismatch, have 0x1e168ca1 expect 0xd413b1e0 ERROR: data at bytenr 175643754496 mirror 1 csum mismatch, have 0x6cfdc8ae expect 0xa6f8f5ef ERROR: extent 175640539136 len 6381568 CORRUPTED, all mirror(s) corrupted, can't be repaired ERROR: data at bytenr 183316750336 mirror 1 csum mismatch, have 0x145bdf76 expect 0x7390565e ..... and the list goes on. Questions: 1. Using "find /mnt -inum 4708" I can link the dmesg to a specific file. Is there a way link the the --offline ERRORs above to the inode? 2. How could do "btrfs device stats /mnt" and normal full scrub fail to detect the csum errors? 3. Do these errors appear to be hardware failure (despite pristine SMART), user error on volume creation/mounting, or an actual btrfs issue? I feel that the need for question #1 indicates a problem with btrfs regardless of whether there is a real hardware failure or not. Next I will try an online scrub of only the sdn device, as before I was running the full filesystem scrub. On Tue, Oct 24, 2017 at 12:52 AM, Lakshmipathi.G wrote: >> Does anyone know why scrub did not catch these errors that show up in dmesg? > > Can you try offline scrub from this repo > https://github.com/gujx2017/btrfs-progs/tree/offline_scrub and see > whether it > detects the issue? "btrfs scrub start --offline " > > > ---- > Cheers, > Lakshmipathi.G > http://www.giis.co.in http://www.webminal.org