btrfs device add hang is reproduced with 3.15.0-0.rc3.git3.1.fc21.x86_64 which has some debugging options enabled; although btrfs options are the same as the non-debug kernel. There is slightly more information in the stack traces however. # grep -i btrfs config-3.15.0-0.rc3.git3.1.fc21.x86_64 CONFIG_BTRFS_FS=m CONFIG_BTRFS_FS_POSIX_ACL=y # CONFIG_BTRFS_FS_CHECK_INTEGRITY is not set # CONFIG_BTRFS_FS_RUN_SANITY_TESTS is not set # CONFIG_BTRFS_DEBUG is not set # CONFIG_BTRFS_ASSERT is not set If btrfs debug set is useful for this let me know and I'll build a kernel with it enabled. Full dmesg with sysrq-w is here: https://drive.google.com/file/d/0B_2Asp8DGjJ9UDN3OUFTUXplNlk/edit?usp=sharing Partial: [ 224.724955] SysRq : Show Blocked State [ 224.725024] task PC stack pid father [ 224.725131] btrfs-transacti D ffff88008571cd40 6456 1162 2 0x00000080 [ 224.725131] ffff880085769d20 0000000000000046 ffff88008571cd40 00000000001d5dc0 [ 224.725131] ffff880085769fd8 00000000001d5dc0 ffff880099194d40 ffff8800966ea210 [ 224.725131] ffff8800854331e8 ffff880085433000 ffff8800854331e8 0000000000000000 [ 224.725131] Call Trace: [ 224.725131] [<ffffffff817ec479>] schedule+0x29/0x70 [ 224.725131] [<ffffffffa00ca01f>] wait_current_trans.isra.19+0xcf/0x120 [btrfs] [ 224.725131] [<ffffffff810eed10>] ? abort_exclusive_wait+0xb0/0xb0 [ 224.725131] [<ffffffffa00cb988>] start_transaction+0x3f8/0x650 [btrfs] [ 224.725131] [<ffffffffa00cbc97>] btrfs_attach_transaction+0x17/0x20 [btrfs] [ 224.725131] [<ffffffffa00c6b5e>] transaction_kthread+0x1de/0x290 [btrfs] [ 224.725131] [<ffffffffa00c6980>] ? btrfs_cleanup_transaction+0x630/0x630 [btrfs] [ 224.725131] [<ffffffff810c3348>] kthread+0x108/0x120 [ 224.725131] [<ffffffff810dbaa8>] ? sched_clock_cpu+0x98/0xc0 [ 224.725131] [<ffffffff810f8f6d>] ? trace_hardirqs_on_caller+0x15d/0x200 [ 224.725131] [<ffffffff810c3240>] ? insert_kthread_work+0x80/0x80 [ 224.725131] [<ffffffff817fc97c>] ret_from_fork+0x7c/0xb0 [ 224.725131] [<ffffffff810c3240>] ? insert_kthread_work+0x80/0x80 [ 224.725131] btrfs D ffff880089053380 2624 1165 997 0x00000080 [ 224.725131] ffff8800850b57f8 0000000000000046 ffff880089053380 00000000001d5dc0 [ 224.725131] ffff8800850b5fd8 00000000001d5dc0 ffff880099194d40 ffff88009d9d6758 [ 224.725131] ffff88009e3e34a8 0000000000000002 ffffffff811b0850 ffff8800850b5870 [ 224.725131] Call Trace: [ 224.725131] [<ffffffff811b0850>] ? wait_on_page_read+0x60/0x60 [ 224.725131] [<ffffffff817ec80f>] io_schedule+0xaf/0x150 [ 224.725131] [<ffffffff811b085e>] sleep_on_page+0xe/0x20 [ 224.725131] [<ffffffff817ecc43>] __wait_on_bit+0x83/0xa0 [ 224.725131] [<ffffffff811b1ab2>] ? find_get_pages_tag+0x2d2/0x370 [ 224.725131] [<ffffffff811b05e9>] wait_on_page_bit+0x89/0xa0 [ 224.725131] [<ffffffff810eed50>] ? autoremove_wake_function+0x40/0x40 [ 224.725131] [<ffffffff811b06f9>] filemap_fdatawait_range+0xf9/0x1c0 [ 224.725131] [<ffffffffa00e6a3c>] btrfs_wait_ordered_range+0x6c/0x150 [btrfs] [ 224.725131] [<ffffffffa01108a0>] __btrfs_write_out_cache+0x640/0x860 [btrfs] [ 224.725131] [<ffffffffa011144d>] btrfs_write_out_cache+0x8d/0xe0 [btrfs] [ 224.725131] [<ffffffffa00ba1f1>] btrfs_write_dirty_block_groups+0x691/0x730 [btrfs] [ 224.725131] [<ffffffffa0142539>] commit_cowonly_roots+0x17a/0x234 [btrfs] [ 224.725131] [<ffffffffa00caf5b>] btrfs_commit_transaction+0x44b/0xa80 [btrfs] [ 224.725131] [<ffffffffa00fa734>] btrfs_init_new_device+0x884/0xeb0 [btrfs] [ 224.725131] [<ffffffff811dfcae>] ? might_fault+0x5e/0xc0 [ 224.725131] [<ffffffff811dfd09>] ? might_fault+0xb9/0xc0 [ 224.725131] [<ffffffffa010392c>] btrfs_ioctl+0xc4c/0x2aa0 [btrfs] [ 224.725131] [<ffffffff8135e8f2>] ? avc_has_perm+0x142/0x350 [ 224.725131] [<ffffffff810dbaa8>] ? sched_clock_cpu+0x98/0xc0 [ 224.725131] [<ffffffff810dbb26>] ? local_clock+0x16/0x30 [ 224.725131] [<ffffffff810f5a7f>] ? lock_release_holdtime.part.28+0xf/0x200 [ 224.725131] [<ffffffff8135e90a>] ? avc_has_perm+0x15a/0x350 [ 224.725131] [<ffffffff8135e7e4>] ? avc_has_perm+0x34/0x350 [ 224.725131] [<ffffffff81360f01>] ? inode_has_perm.isra.47+0x51/0x90 [ 224.725131] [<ffffffff812513e0>] do_vfs_ioctl+0x2f0/0x520 [ 224.725131] [<ffffffff81251691>] SyS_ioctl+0x81/0xa0 [ 224.725131] [<ffffffff81155eac>] ? __audit_syscall_entry+0x9c/0xf0 [ 224.725131] [<ffffffff817fca29>] system_call_fastpath+0x16/0x1b [ 224.725131] Sched Debug Version: v0.11, 3.15.0-0.rc3.git3.1.fc21.x86_64 #1 -- 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
