Bug 205655 - kvm with cache=none and btrfs -> corrupted file system
Summary: kvm with cache=none and btrfs -> corrupted file system
Status: NEW
Alias: None
Product: Virtualization
Classification: Unclassified
Component: kvm (show other bugs)
Hardware: x86-64 Linux
: P1 high
Assignee: virtualization_kvm
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2019-11-26 09:24 UTC by denis.ovsyannikov
Modified: 2019-12-03 09:08 UTC (History)
0 users

See Also:
Kernel Version: 4.9 4.19 5.3.12
Subsystem:
Regression: No
Bisected commit-id:

Attachments
signature.asc (488 bytes, application/pgp-signature)
2019-12-03 09:08 UTC, Stefan Hajnoczi 		Details
Add an attachment (proposed patch, testcase, etc.)

Description denis.ovsyannikov 2019-11-26 09:24:48 UTC 
hello
we use kvm with disks formatted in btrfs
when we turned on the mode "cache=none"
got data corruption
other modes work well

we tested it on three servers and the result is always repeated
we tested on three operating systems(debian 9, debian 10, manjaro with kernel 5.3.12)

fstab
UUID=a49494f2-35a4-4a9c-aab0-1afc905c02c2 /mnt/test      btrfs   defaults 0 2

dmesg
[675174.887900] BTRFS error (device sde1): bdev /dev/sde1 errs: wr 0, rd 0, flush 0, corrupt 2137, gen 0

[102857.086874] BTRFS warning (device sdc1): csum failed root 256 ino 260 off 1735843840 csum 0xf69f8dd2 expected csum 0x96e71981 mirror 1
Comment 1 denis.ovsyannikov 2019-11-26 11:48:49 UTC 
I made a mistake, directsync mode also corrupts data
Comment 2 Stefan Hajnoczi 2019-12-03 09:08:31 UTC 
Created attachment 286155 [details]
signature.asc

On Tue, Nov 26, 2019 at 09:24:48AM +0000, bugzilla-daemon@bugzilla.kernel.org wrote:
> https://bugzilla.kernel.org/show_bug.cgi?id=205655
> 
>             Bug ID: 205655
>            Summary: kvm with cache=none and btrfs -> corrupted file system
>            Product: Virtualization
>            Version: unspecified
>     Kernel Version: 4.9   4.19    5.3.12
>           Hardware: x86-64
>                 OS: Linux
>               Tree: Mainline
>             Status: NEW
>           Severity: high
>           Priority: P1
>          Component: kvm
>           Assignee: virtualization_kvm@kernel-bugs.osdl.org
>           Reporter: denis.ovsyannikov@gmail.com
>         Regression: No
> 
> hello
> we use kvm with disks formatted in btrfs
> when we turned on the mode "cache=none"
> got data corruption
> other modes work well
> 
> we tested it on three servers and the result is always repeated
> we tested on three operating systems(debian 9, debian 10, manjaro with kernel
> 5.3.12)
> 
> fstab
> UUID=a49494f2-35a4-4a9c-aab0-1afc905c02c2 /mnt/test      btrfs   defaults 0 2
> 
> dmesg
> [675174.887900] BTRFS error (device sde1): bdev /dev/sde1 errs: wr 0, rd 0,
> flush 0, corrupt 2137, gen 0
> 
> [102857.086874] BTRFS warning (device sdc1): csum failed root 256 ino 260 off
> 1735843840 csum 0xf69f8dd2 expected csum 0x96e71981 mirror 1

Please post your QEMU command-line.

What is the storage configuration on the host?  Which host file system
are you using?  Which image file format?

What test is being run inside the guest?

Is this a regression?  Which host and guest kernel versions worked fine
before?
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