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(). Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
