On Thu, Mar 22, 2012 at 01:25:26PM +0800, Miao Xie wrote: > On Thu, 22 Mar 2012 15:39:36 +1100, Dave Chinner wrote: > > On Thu, Mar 22, 2012 at 11:13:17AM +0800, Miao Xie wrote: > >> The reason the deadlock is that: > >> Task Btrfs-cleaner > >> umount() > >> down_write(&s->s_umount) > >> close_ctree() > >> wait for the end of > >> btrfs-cleaner > >> start_transaction > >> reserve space > >> shrink_delalloc() > >> writeback_inodes_sb_nr_if_idle() > >> down_read(&sb->s_umount) > >> So, the deadlock has happened. > > > > Every time a deadlock involving writeback_inodes_sb...if_idle() > > comes up, I give the same response. If the s_umount is write locked, > > then the sb is not idle. IOWs, writeback_inodes_sb...if_idle() > > should be doing down_read_trylock(), not down_read(). > > Someone did this work several months ago, but those patches have not been > applied until now, so...
... work to get them into the current/next release. Cheers, Dave. -- Dave Chinner [email protected] -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
