Re: Corruption errors on Samsung 980 Pro

[Martin Steigerwald <martin@lichtvoll.de>]

Martin Steigerwald - 16.07.21, 17:05:59 CEST:
> I migrated to a different laptop and this one has a 2TB Samsung 980 Pro drive
> (not a 2TB Samsung 870 Evo Plus which previously had problems).

Kernel is:

% cat /proc/version
Linux version 5.13.1-t14 (martin@[…]) (gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2) #14 SMP PREEMPT Mon Jul 12 10:36:54 CEST 2021

> I thought this time I would be fine, but I just got:
> 
> [63168.287911] BTRFS warning (device dm-3): csum failed root 1372 ino 2295743 off 2718461952 csum 0x48be03222606a29d expected csum 0x0100000026004000 mirror 1
> [63168.287925] BTRFS error (device dm-3): bdev /dev/mapper/nvme-home errs: wr 0, rd 0, flush 0, corrupt 1, gen 0
> [63168.346552] BTRFS warning (device dm-3): csum failed root 1372 ino 2295743 off 2718461952 csum 0x48be03222606a29d expected csum 0x0100000026004000 mirror 1
> [63168.346567] BTRFS error (device dm-3): bdev /dev/mapper/nvme-home errs: wr 0, rd 0, flush 0, corrupt 2, gen 0
> [63168.346685] BTRFS warning (device dm-3): csum failed root 1372 ino 2295743 off 2718461952 csum 0x48be03222606a29d expected csum 0x0100000026004000 mirror 1
> [63168.346708] BTRFS error (device dm-3): bdev /dev/mapper/nvme-home errs: wr 0, rd 0, flush 0, corrupt 3, gen 0
> [63168.346859] BTRFS warning (device dm-3): csum failed root 1372 ino 2295743 off 2718461952 csum 0x48be03222606a29d expected csum 0x0100000026004000 mirror 1
> [63168.346873] BTRFS error (device dm-3): bdev /dev/mapper/nvme-home errs: wr 0, rd 0, flush 0, corrupt 4, gen 0
> [63299.490367] BTRFS warning (device dm-3): csum failed root 1372 ino 2295743 off 2718461952 csum 0x48be03222606a29d expected csum 0x0100000026004000 mirror 1
> [63299.490384] BTRFS error (device dm-3): bdev /dev/mapper/nvme-home errs: wr 0, rd 0, flush 0, corrupt 5, gen 0
> [63299.572849] BTRFS warning (device dm-3): csum failed root 1372 ino 2295743 off 2718461952 csum 0x48be03222606a29d expected csum 0x0100000026004000 mirror 1
> [63299.572866] BTRFS error (device dm-3): bdev /dev/mapper/nvme-home errs: wr 0, rd 0, flush 0, corrupt 6, gen 0
> [63299.573151] BTRFS warning (device dm-3): csum failed root 1372 ino 2295743 off 2718461952 csum 0x48be03222606a29d expected csum 0x0100000026004000 mirror 1
> [63299.573168] BTRFS error (device dm-3): bdev /dev/mapper/nvme-home errs: wr 0, rd 0, flush 0, corrupt 7, gen 0
> [63299.573286] BTRFS warning (device dm-3): csum failed root 1372 ino 2295743 off 2718461952 csum 0x48be03222606a29d expected csum 0x0100000026004000 mirror 1
> [63299.573295] BTRFS error (device dm-3): bdev /dev/mapper/nvme-home errs: wr 0, rd 0, flush 0, corrupt 8, gen 0
> [63588.902631] BTRFS warning (device dm-3): csum failed root 1372 ino 4895964 off 34850111488 csum 0x21941ce6e9739bd6 expected csum 0xc113140701000000 mirror 1
> [63588.902647] BTRFS error (device dm-3): bdev /dev/mapper/nvme-home errs: wr 0, rd 0, flush 0, corrupt 13, gen 0
> [63588.949614] BTRFS warning (device dm-3): csum failed root 1372 ino 4895964 off 34850111488 csum 0x21941ce6e9739bd6 expected csum 0xc113140701000000 mirror 1
> [63588.949628] BTRFS error (device dm-3): bdev /dev/mapper/nvme-home errs: wr 0, rd 0, flush 0, corrupt 14, gen 0
> [63588.949849] BTRFS warning (device dm-3): csum failed root 1372 ino 4895964 off 34850111488 csum 0x21941ce6e9739bd6 expected csum 0xc113140701000000 mirror 1
> [63588.949855] BTRFS error (device dm-3): bdev /dev/mapper/nvme-home errs: wr 0, rd 0, flush 0, corrupt 15, gen 0
> [63588.950087] BTRFS warning (device dm-3): csum failed root 1372 ino 4895964 off 34850111488 csum 0x21941ce6e9739bd6 expected csum 0xc113140701000000 mirror 1
> [63588.950099] BTRFS error (device dm-3): bdev /dev/mapper/nvme-home errs: wr 0, rd 0, flush 0, corrupt 16, gen 0

Additional errors revealed through scrubbing – will test the other
filesystems as well:

% btrfs scrub status /home
UUID:             […]
Scrub started:    Fri Jul 16 17:08:49 2021
Status:           finished
Duration:         0:02:05
Total to scrub:   203.54GiB
Rate:             1.63GiB/s
Error summary:    csum=5
  Corrected:      0
  Uncorrectable:  5
  Unverified:     0

Now totalling to 21 errors:

% btrfs device stats /home
[/dev/mapper/nvme-home].write_io_errs    0
[/dev/mapper/nvme-home].read_io_errs     0
[/dev/mapper/nvme-home].flush_io_errs    0
[/dev/mapper/nvme-home].corruption_errs  21
[/dev/mapper/nvme-home].generation_errs  0

Log:

[64707.979036] BTRFS info (device dm-3): scrub: started on devid 1
[64730.009687] BTRFS warning (device dm-3): checksum error at logical 36997591040 on dev /dev/mapper/nvme-home, physical 34850107392, root 1054, inode 2295743, offset 2718461952: path resolving failed with ret=-2
[64730.009710] BTRFS error (device dm-3): bdev /dev/mapper/nvme-home errs: wr 0, rd 0, flush 0, corrupt 17, gen 0
[64730.009721] BTRFS error (device dm-3): unable to fixup (regular) error at logical 36997591040 on dev /dev/mapper/nvme-home
[64730.010996] BTRFS warning (device dm-3): checksum error at logical 36997595136 on dev /dev/mapper/nvme-home, physical 34850111488, root 1054, inode 4895964, offset 7676579840: path resolving failed with ret=-2
[64730.011014] BTRFS error (device dm-3): bdev /dev/mapper/nvme-home errs: wr 0, rd 0, flush 0, corrupt 18, gen 0
[64730.011024] BTRFS error (device dm-3): unable to fixup (regular) error at logical 36997595136 on dev /dev/mapper/nvme-home
[64730.011298] BTRFS warning (device dm-3): checksum error at logical 36997599232 on dev /dev/mapper/nvme-home, physical 34850115584, root 1054, inode 4895964, offset 7676579840: path resolving failed with ret=-2
[64730.011312] BTRFS error (device dm-3): bdev /dev/mapper/nvme-home errs: wr 0, rd 0, flush 0, corrupt 19, gen 0
[64730.011319] BTRFS error (device dm-3): unable to fixup (regular) error at logical 36997599232 on dev /dev/mapper/nvme-home
[64730.011603] BTRFS warning (device dm-3): checksum error at logical 36997603328 on dev /dev/mapper/nvme-home, physical 34850119680, root 1054, inode 4895964, offset 7676579840: path resolving failed with ret=-2
[64730.011616] BTRFS error (device dm-3): bdev /dev/mapper/nvme-home errs: wr 0, rd 0, flush 0, corrupt 20, gen 0
[64730.011623] BTRFS error (device dm-3): unable to fixup (regular) error at logical 36997603328 on dev /dev/mapper/nvme-home
[64730.011905] BTRFS warning (device dm-3): checksum error at logical 36997607424 on dev /dev/mapper/nvme-home, physical 34850123776, root 1054, inode 4895964, offset 7676579840: path resolving failed with ret=-2
[64730.011921] BTRFS error (device dm-3): bdev /dev/mapper/nvme-home errs: wr 0, rd 0, flush 0, corrupt 21, gen 0
[64730.011928] BTRFS error (device dm-3): unable to fixup (regular) error at logical 36997607424 on dev /dev/mapper/nvme-home
[64832.447560] BTRFS info (device dm-3): scrub: finished on devid 1 with status: 0

Why is BTRFS unable to determine a path?

How would I fix those when BTRFS does not tell me what file is affected?

> during a backup.
> 
> According to rsync this is related (why does BTRFS does not report the
> affected file?)
> 
> Create a snapshot of '/home' in '/zeit/home/backup-2021-07-16-16:40:13'
> rsync: [sender] read errors mapping "/zeit/home/backup-2021-07-16-16:40:13/martin/.local/share/akonadi/search_db/email/postlist.glass": Input/output error (5)
> rsync: [sender] read errors mapping "/zeit/home/backup-2021-07-16-16:40:13/martin/.local/share/akonadi/search_db/email/postlist.glass": Input/output error (5)
> ERROR: martin/.local/share/akonadi/search_db/email/postlist.glass failed verification -- update discarded.
> rsync: [sender] read errors mapping "/zeit/home/backup-2021-07-16-16:40:13/martin/.local/share/baloo/index": Input/output error (5)
> rsync: [sender] read errors mapping "/zeit/home/backup-2021-07-16-16:40:13/martin/.local/share/baloo/index": Input/output error (5)
> ERROR: martin/.local/share/baloo/index failed verification -- update discarded.
> 
> Both are frequently written to files (both Baloo and Akonadi have very crazy
> I/O patterns that, I would not have thought so, can even satisfy an NVMe SSD).
> 
> I thought that a Samsung 980 Pro can easily handle "discard=async" so I
> used it.
> 
> This is on a ThinkPad T14 Gen1 with AMD Ryzen 7 PRO 4750U and 32 GiB of RAM.
> 
> It is BTRFS single profile on LVM on LUKS. Mount options are:
> 
> rw,relatime,lazytime,compress=zstd:3,ssd,space_cache=v2,subvolid=1054,subvol=/home
> 
> Smartctl has no errors.
> 
> I only use a few (less than 10) subvolumes.
> 
> I do not have any other errors in kernel log, so I bet this may not be
> "discard=async" related. Any idea?

Maybe I still remove "discard=async" for now. Maybe it is not yet fully reliable.

> Could it have to do with a sudden switching off the laptop (there had
> been quite some reasons cause at least with a AMD model of this laptop
> in combination with an USB-C dock by Lenovo there are quite some stability
> issues)? I would have hoped that the Samsung 980 Pro would still be
> equipped to complete the outstanding write operation, but maybe it has
> no capacitor for this.
> 
> I am really surprised by the what I experienced about the reliability of
> SSDs I recently bought. I did not see a failure within a month with any
> of the older SSDs. I hope this does not point at a severe worsening of
> the quality. Probably I have to fit another SSD in there and use BTRFS
> RAID 1 again to protect at least part of the data from errors like this.
> 
> Any idea about this? I bet you may not have any, as there is not block
> I/O related errors in the log, but if you have, by all means share your
> thoughts. Thank you.
> 
> Both files can be recreated. So I bet I will just remove them.
> 
> Best,
-- 
Martin