Re: btrfs random filesystem corruption in kernel 3.17

[john terragon <jterragon@gmail.com>]

I think I just found a consistent simple way to trigger the problem
(at least on my system). And, as I guessed before, it seems to be
related just to readonly snapshots:

1) I create a readonly snapshot
2) I do some changes on the source subvolume for the snapshot (I'm not
sure changes are strictly needed)
3) reboot (or probably just unmount and remount. I reboot because the
fs I've problems with contains my root subvolume)

After the rebooting (or the remount) I consistently have the corruption
with the usual multitude of these in dmesg
"parent transid verify failed on 902316032 wanted 2484 found 4101"
and the characteristic ls -la output

drwxr-xr-x 1 root root  250 Oct 10 15:37 root
d????????? ? ?    ?       ?            ? root-b2
drwxr-xr-x 1 root root  250 Oct 10 15:37 root-b3
d????????? ? ?    ?       ?            ? root-backup

root-backup and root-b2 are both readonly whereas root-b3 is rw (and
it didn't get corrupted).

David, maybe you can try the same steps on one of your machines?

John