On Fri, Mar 14, 2014 at 02:51:22PM -0400, Josef Bacik wrote: > On 03/13/2014 06:16 PM, Hugo Mills wrote: > >On Thu, Mar 13, 2014 at 03:42:13PM -0400, Josef Bacik wrote: > >>Lets try this again. We can deadlock the box if we send on a box and try to > >>write onto the same fs with the app that is trying to listen to the send > >>pipe. > >>This is because the writer could get stuck waiting for a transaction commit > >>which is being blocked by the send. So fix this by making sure looking at > >>the > >>commit roots is always going to be consistent. We do this by keeping track > >>of > >>which roots need to have their commit roots swapped during commit, and then > >>taking the commit_root_sem and swapping them all at once. Then make sure we > >>take a read lock on the commit_root_sem in cases where we search the commit > >>root > >>to make sure we're always looking at a consistent view of the commit roots. > >>Previously we had problems with this because we would swap a fs tree commit > >>root > >>and then swap the extent tree commit root independently which would cause > >>the > >>backref walking code to screw up sometimes. With this patch we no longer > >>deadlock and pass all the weird send/receive corner cases. Thanks, > > > > There's something still going on here. I managed to get about twice > >as far through my test as I had before, but I again got an "unexpected > >EOF in stream", with btrfs send returning 1. As before, I have this in > >syslog: > > > >Mar 13 22:09:12 s_src@amelia kernel: BTRFS error (device sda2): did not find > >backref in send_root. inode=1786631, offset=825257984, disk_byte=36504023040 > >found extent=36504023040\x0a > > > > I just noticed that the offset you have there is freaking gigantic, > like 700mb, which is way larger than what an extent should be. Here > is a newer debug patch, just chuck the old on and put this instead > and re-run > > http://paste.fedoraproject.org/85486/39482301
That last run, with the above patch, failed again, at approximately the same place again. The only output in dmesg is: [ 6488.168469] BTRFS error (device sda2): did not find backref in send_root. inode=1786631, offset=825257984, disk_byte=36504023040 found extent=36504023040, len=1294336 as before. Definitely no kernel WARN, no backtraces. Hugo. -- === Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk === PGP key: 65E74AC0 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk --- You're never alone with a rubber duck... ---
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