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... https://lkml.org/lkml/2011/12/8/264 Thanks Miao -- 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
