On Wed, Oct 13, 2010 at 07:36:48PM -0400, Christoph Hellwig wrote: > On Wed, Oct 13, 2010 at 05:46:09PM -0400, Christoph Hellwig wrote: > > On Wed, Oct 13, 2010 at 11:58:45AM -0400, Christoph Hellwig wrote: > > > > > > It's 100% reproducible on my kvm VM. The bug is the assert_spin_locked > > > in redirty_tail. I really can't find a way how we reach it without > > > d_lock so this really confuses me. > > > > We are for some reason getting a block device inode that is on the > > dirty list of a bdi that it doesn't point to. Still trying to figure > > out how exactly that happens. > > It's because __blkdev_put reset the bdi on the mapping, and bdev inodes > are still special cased to not use s_bdi unlike everybody else. So > we keep switch between different bdis that get locked. > > I wonder what's a good workaround for that. Just flushing out all > dirty state of a block device inode on last close would fix, but we'd > still have all the dragons hidden underneath until we finally sort > out the bdi reference mess. Perhaps for the moment make __blkdev_put() move the inode onto the dirty lists for the default bdi when it switches themîin the mapping? e.g. add a "inode_switch_bdi" helper that is only called in this case? Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
