Hi Miao, My virtual machine hangs upon reboot. INFO: task umount:1952 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. umount D 00000000fffd44dc 3024 1952 1714 0x00000000 ffff880051ea99e8 0000000000000046 ffff880000000000 ffff880051ea9fd8 00000000001d4240 ffff88005cd958d0 ffff88005cd95e60 ffff88005cd95e58 ffff880051ea8000 ffff880051ea9fd8 00000000001d4240 00000000001d4240 Call Trace: [<ffffffff811d2697>] ? start_transaction+0x7b/0x1f8 [<ffffffff814b5593>] __mutex_lock_common+0x28c/0x444 [<ffffffff811d2697>] ? start_transaction+0x7b/0x1f8 [<ffffffff814b5800>] mutex_lock_nested+0x39/0x3e [<ffffffff811d2697>] start_transaction+0x7b/0x1f8 [<ffffffff811d2857>] btrfs_join_transaction+0x15/0x17 [<ffffffff8120e873>] btrfs_remove_delayed_node+0x36/0xa1 [<ffffffff811d32ae>] btrfs_destroy_inode+0x2ae/0x2cc [<ffffffff8112d1c9>] destroy_inode+0x2f/0x45 [<ffffffff8112da86>] iput+0x239/0x23e [<ffffffff811c7992>] btrfs_write_dirty_block_groups+0x22a/0x47c [<ffffffff811d0f46>] commit_cowonly_roots+0xd9/0x198 [<ffffffff811d20fc>] btrfs_commit_transaction+0x3a0/0x658 [<ffffffff814b5176>] ? __mutex_unlock_slowpath+0x129/0x13a [<ffffffff810603de>] ? autoremove_wake_function+0x0/0x39 [<ffffffff811cf152>] btrfs_commit_super+0x90/0xd9 [<ffffffff811cf1e5>] close_ctree+0x4a/0x35c [<ffffffff810648f5>] ? up_write+0x23/0x3b [<ffffffff8112d83b>] ? invalidate_inodes+0x134/0x146 [<ffffffff811b5989>] btrfs_put_super+0x1d/0x2c [<ffffffff8111c08d>] generic_shutdown_super+0x56/0xd7 [<ffffffff8111c163>] kill_anon_super+0x16/0x54 [<ffffffff8111b895>] ? deactivate_super+0x3d/0x4a [<ffffffff8111b405>] deactivate_locked_super+0x26/0x46 [<ffffffff8111b89d>] deactivate_super+0x45/0x4a [<ffffffff81131d6a>] mntput_no_expire+0xd6/0x104 [<ffffffff81132e8f>] sys_umount+0x2c1/0x2ec [<ffffffff81002ddb>] system_call_fastpath+0x16/0x1b INFO: lockdep is turned off. btrfs_remove_delayed_node() is called while trans_mutex is held. Itaru -- 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
