Hi, Chris > -----Original Message----- > From: linux-btrfs-ow...@vger.kernel.org > [mailto:linux-btrfs-ow...@vger.kernel.org] On Behalf Of Qu Wenruo > Sent: Tuesday, July 28, 2015 3:11 PM > To: Chris Mason; btrfs > Subject: Re: [GIT PULL] Fix for btrfs/070 checksum error > > Chris Mason wrote on 2015/07/23 21:57 -0400: > > On Fri, Jul 24, 2015 at 08:29:05AM +0800, Qu Wenruo wrote: > > > > [ deadlock with the 070 patches ] > > > >> Thanks Chris > >> > >> We will investigate it with highest priority. > >> > >> Thanks, > >> Qu > >> > > > > Thanks! I'm doing a few more runs to make sure the lockup is new with > > these patches. > > > > -chris > > > Hi Chris, > > I'm very sorry that we are unable to fix the lockup in a short time, so it > may not > fit in the v4.2 merge window. > > Please ignore this patchset for now. >
Sorry for taking quite a long time for investigate because it is randomly happened. We got reason of process blocking: 1: In some case, this patch caused __btrfs_cow_block()->btrfs_reloc_cow_block() failed from btrfs_balance operation.(need more investigation) 2: __btrfs_cow_block()'s error handle code hadn't unlock/free new_allocated tree block before return error. 3: do_relocation(), which is caller of __btrfs_cow_block(), have error handle code, but also can't work in this case, because new_allocated eb is not returned. 4: subsequent code in do_relocation() try to lock above eb again, and caused dead lock. In short: do_relocation() -> __btrfs_cow_block() failed without unlock eb *1 ... -> btrfs_search_slot() try to lock above eb again ... *1: this fail is caused by scrub Because eb locking code is not normal lock, we can't get information from lockldep in this case. Things to do: 1: Fix this patch to avoid making __btrfs_cow_block() fails. 2: Fix __btrfs_cow_block() to do enough cleanup in error handle code. 3: Some enhance for eb locking, to report some information to helps similar error. Thanks Zhaolei > Thanks, > Qu > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the > body > of a message to majord...@vger.kernel.org More majordomo info at > http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
