Hi all, This bug will be triggered when dioread_nolock enables. In 3.8 kernel, the test will be blocked for more than 120s, and we get the following messages. *But* in dev branch the system will hang silently without any messages. I need to run test 7 times to hit it. wenqing: run xfstest 269 kernel: EXT4-fs (sda2): mounted filesystem with ordered data mode. Opts: acl,user_xattr,dioread_nolock kernel: INFO: task umount:3376 blocked for more than 120 seconds. kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kernel: umount D 0000000000000001 0 3376 3003 0x00000000 kernel: ffff880117417cd8 0000000000000082 ffff880117417bd8 ffff880117416010 kernel: ffff880112d12110 0000000000012080 ffff880117417fd8 0000000000004000 kernel: ffff880117417fd8 0000000000012080 ffff88011331d950 ffff880112d12110 kernel: Call Trace: kernel: [<ffffffff820ba03c>] ? pagevec_lookup+0x22/0x2b kernel: [<ffffffff820bb526>] ? truncate_inode_pages_range+0x273/0x3a2 kernel: [<ffffffff8237ef2f>] schedule+0x64/0x66 kernel: [<ffffffffa0203d7c>] ext4_ioend_wait+0x87/0x9f [ext4] kernel: [<ffffffff8204f0be>] ? wake_up_bit+0x2a/0x2a kernel: [<ffffffffa0201396>] ext4_evict_inode+0x4a/0x41d [ext4] kernel: [<ffffffff82102c8c>] evict+0xa2/0x15b kernel: [<ffffffff821ba2b8>] ? __list_del_entry+0x51/0x98 kernel: [<ffffffff821031b7>] dispose_list+0x3e/0x50 kernel: [<ffffffff8210365b>] evict_inodes+0xdb/0xe7 kernel: [<ffffffff820ef954>] generic_shutdown_super+0x4c/0xd3 kernel: [<ffffffff820efa02>] kill_block_super+0x27/0x69 kernel: [<ffffffff820efe56>] deactivate_locked_super+0x26/0x52 kernel: [<ffffffff820f0ad2>] deactivate_super+0x45/0x4a kernel: [<ffffffff821074b9>] mntput_no_expire+0x110/0x118 kernel: [<ffffffff82108331>] sys_umount+0x306/0x331 kernel: [<ffffffff82041bf6>] ? sigprocmask+0x63/0x67 kernel: [<ffffffff82386942>] system_call_fastpath+0x16/0x1b Regards, - Zheng -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html