Re: 3.15-rc5 btrfs send/receive corruption errors? Does scrub warn of silent corruption?

[Marc MERLIN <marc@merlins.org>]

On Sat, May 10, 2014 at 04:57:18PM -0700, Marc MERLIN wrote:
> On Sat, May 10, 2014 at 03:42:49PM -0700, Marc MERLIN wrote:
> > I tried with 3.14.3 and it went further, however it died with
> > legolas:/mnt/btrfs_pool2# btrfs send  home_ro.20140507_10:00:01 | btrfs receive /mnt/btrfs_pool1/
> > At subvol home_ro.20140507_10:00:01
> > At subvol home_ro.20140507_10:00:01
> > ERROR: send ioctl failed with -5: Input/output error
> > ERROR: unexpected EOF in stream.
> > 
> > I'll look up -5 later when I have time, but I guess there is a problem
> > on the source that is causing copies to fail with both kernels?
> 
> This brings me back to the earlier question:
> 
> When my other FS died, scrub ran ok just earlier.
> 
> Now, having 2 btrfs sends (not incremental, full) fail with 2 kernels
> would indicate that something might be wrong on the source filesystem.
> 
> Yet, last night's scrub ran fine too:
> 
> On Fri, May 09, 2014 at 11:39:13AM -0700, Anacron wrote:
> > /etc/cron.daily/btrfs-scrub:
> > scrub device /dev/mapper/cryptroot (id 1) done
> > 	scrub started at Fri May  9 06:09:14 2014 and finished after 19153 seconds
> > 	total bytes scrubbed: 646.15GiB with 0 errors
> 
> So, does scrub actually make sure everything on my filesystem is sane,
> or can it miss some kinds of corruptions?

I'm thinking that there must be some corruption on btrfs_pool2,
because:

On Sat, May 10, 2014 at 06:06:46PM -0600, Chris Murphy wrote:
> I think the issue might be there are still problems and changing code on the receive side (btrfs-progs). The kernel side code responsible for send is probably working correctly.

I tried
3.15 and progs 3.12
3.15 and progs 3.14
3.14 and progs 3.12
3.14 and progs 3.14

All 4 failed to run
legolas:/mnt/btrfs_pool2# btrfs send home_ro.20140507_10:00:01 | btrfs receive /mnt/btrfs_pool1/

3.14 gives:
ERROR: send ioctl failed with -5: Input/output error
ERROR: unexpected EOF in stream.

3.15 gives a more detailled message how it can't rename some corrupted
filename (regardless of whether I use progs 3.12 or 3.14).

So, since scrub tells me my FS is ok, is scrub right, or do I have a
file pattern that is causing a bug in btrfs send ?

Thanks,
Marc
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