root@yoyo:/# btrfs fi df / Data, RAID1: total=9.00GiB, used=6.95GiB System, RAID1: total=32.00MiB, used=16.00KiB Metadata, RAID1: total=1.00GiB, used=82.95MiB root@yoyo:/# df -h / Filesystem Size Used Avail Use% Mounted on /dev/sda2 273G 15G 257G 6% / I have a Xen server that has a RAID-1 array of 2*140G SAS disks, above is the df output. The Xen server is for training and testing (including training people to use BTRFS), hence the name. I have a subvol /xenstore which has image files for BTRFS RAID-1 filesystems (RAID-1 within RAID-1 is going to suck for performance but be good for training, and apparently testing). root@yoyo:/# mount -o loop,degraded /xenstore/btrfsa /mnt/tmp I mounted one of them loopback with the above command and then tried doing an "apt-get update" in a chroot. The result was that apt-get entered D state and the following was in the kernel message log. The system is running Debian kernel 3.14.9. [ 2280.784105] INFO: task btrfs-flush_del:1339 blocked for more than 120 seconds. [ 2280.784126] Not tainted 3.14-1-amd64 #1 [ 2280.784136] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 2280.784152] btrfs-flush_del D ffff8800547f0cf8 0 1339 2 0x00000000 [ 2280.784173] ffff8800547f08e0 0000000000000246 0000000000014380 ffff8800547f5fd8 [ 2280.784232] 0000000000014380 ffff8800547f08e0 ffff880077454c10 ffff88007777c028 [ 2280.784290] 0000000000000002 ffffffff8111f240 ffff8800547f5ce0 ffff8800547f5dc8 [ 2280.784347] Call Trace: [ 2280.784376] [<ffffffff8111f240>] ? wait_on_page_read+0x60/0x60 [ 2280.784410] [<ffffffff814bcd54>] ? io_schedule+0x94/0x130 [ 2280.784440] [<ffffffff8111f245>] ? sleep_on_page+0x5/0x10 [ 2280.784470] [<ffffffff814bd0c4>] ? __wait_on_bit+0x54/0x80 [ 2280.784501] [<ffffffff8111f04f>] ? wait_on_page_bit+0x7f/0x90 [ 2280.784534] [<ffffffff8109e300>] ? autoremove_wake_function+0x30/0x30 [ 2280.784566] [<ffffffff8112c008>] ? pagevec_lookup_tag+0x18/0x20 [ 2280.784597] [<ffffffff8111f130>] ? filemap_fdatawait_range+0xd0/0x160 [ 2280.784654] [<ffffffffa0230da5>] ? btrfs_wait_ordered_range+0x65/0x120 [btrfs] [ 2280.784709] [<ffffffffa021d7a1>] ? btrfs_run_delalloc_work+0x21/0x80 [btrfs] [ 2280.784750] [<ffffffffa02449b0>] ? worker_loop+0x140/0x520 [btrfs] [ 2280.784782] [<ffffffff814bc5e9>] ? __schedule+0x2a9/0x700 [ 2280.784820] [<ffffffffa0244870>] ? btrfs_queue_worker+0x300/0x300 [btrfs] [ 2280.784854] [<ffffffff8107f858>] ? kthread+0xb8/0xd0 [ 2280.784884] [<ffffffff8107f7a0>] ? kthread_create_on_node+0x180/0x180 [ 2280.784917] [<ffffffff814c7acc>] ? ret_from_fork+0x7c/0xb0 [ 2280.784948] [<ffffffff8107f7a0>] ? kthread_create_on_node+0x180/0x180 [ 2280.784980] INFO: task btrfs-transacti:1343 blocked for more than 120 seconds. [ 2280.785028] Not tainted 3.14-1-amd64 #1 [ 2280.785055] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 2280.785105] btrfs-transacti D ffff8800547c4968 0 1343 2 0x00000000 [ 2280.785142] ffff8800547c4550 0000000000000246 0000000000014380 ffff880054055fd8 [ 2280.785200] 0000000000014380 ffff8800547c4550 ffff88004f063f70 ffff880054055d78 [ 2280.785257] ffff88004f063f68 ffff8800547c4550 ffff880056047de0 ffff880054055df0 [ 2280.785314] Call Trace: [ 2280.785340] [<ffffffff814bbe49>] ? schedule_timeout+0x209/0x2a0 [ 2280.785372] [<ffffffff81095b6f>] ? enqueue_task_fair+0x2bf/0xdf0 [ 2280.785403] [<ffffffff81091337>] ? sched_clock_cpu+0x47/0xb0 [ 2280.785434] [<ffffffff8131dc6b>] ? notify_remote_via_irq+0x2b/0x50 [ 2280.785466] [<ffffffff8108bee5>] ? check_preempt_curr+0x65/0x90 [ 2280.785497] [<ffffffff8108bf1f>] ? ttwu_do_wakeup+0xf/0xc0 [ 2280.785528] [<ffffffff814bd3f0>] ? wait_for_completion+0xa0/0x110 [ 2280.785560] [<ffffffff8108e7a0>] ? wake_up_state+0x10/0x10 [ 2280.785599] [<ffffffffa02273dd>] ? btrfs_wait_and_free_delalloc_work+0xd/0x20 [btrfs] [ 2280.785656] [<ffffffffa02304f6>] ? btrfs_run_ordered_operations+0x1e6/0x2b0 [btrfs] [ 2280.785712] [<ffffffffa02182b7>] ? btrfs_commit_transaction+0x217/0x990 [btrfs] [ 2280.785768] [<ffffffffa0218abb>] ? start_transaction+0x8b/0x550 [btrfs] [ 2280.785807] [<ffffffffa021432d>] ? transaction_kthread+0x1ad/0x240 [btrfs] [ 2280.785846] [<ffffffffa0214180>] ? btrfs_cleanup_transaction+0x510/0x510 [btrfs] [ 2280.785894] [<ffffffff8107f858>] ? kthread+0xb8/0xd0 [ 2280.785924] [<ffffffff8107f7a0>] ? kthread_create_on_node+0x180/0x180 [ 2280.785956] [<ffffffff814c7acc>] ? ret_from_fork+0x7c/0xb0 [ 2280.785985] [<ffffffff8107f7a0>] ? kthread_create_on_node+0x180/0x180 [ 2280.786017] INFO: task apt-get:1358 blocked for more than 120 seconds. [ 2280.786047] Not tainted 3.14-1-amd64 #1 [ 2280.786074] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 2280.786122] apt-get D ffff88005bce2d78 0 1358 1357 0x00000000 [ 2280.786159] ffff88005bce2960 0000000000000286 0000000000014380 ffff88005a681fd8 [ 2280.786218] 0000000000014380 ffff88005bce2960 ffff880077494c10 ffff880077778248 [ 2280.786277] 0000000000000002 ffffffff8111f240 ffff88005a681da0 ffff88005a681e48 [ 2280.786334] Call Trace: [ 2280.786360] [<ffffffff8111f240>] ? wait_on_page_read+0x60/0x60 [ 2280.786392] [<ffffffff814bcd54>] ? io_schedule+0x94/0x130 [ 2280.786422] [<ffffffff8111f245>] ? sleep_on_page+0x5/0x10 [ 2280.786453] [<ffffffff814bd0c4>] ? __wait_on_bit+0x54/0x80 [ 2280.786484] [<ffffffff8111f04f>] ? wait_on_page_bit+0x7f/0x90 [ 2280.786515] [<ffffffff8109e300>] ? autoremove_wake_function+0x30/0x30 [ 2280.786548] [<ffffffff8112c008>] ? pagevec_lookup_tag+0x18/0x20 [ 2280.786579] [<ffffffff8111f130>] ? filemap_fdatawait_range+0xd0/0x160 [ 2280.786620] [<ffffffffa0236d62>] ? extent_writepages+0x52/0x60 [btrfs] [ 2280.786660] [<ffffffffa021c850>] ? btrfs_submit_direct+0x6b0/0x6b0 [btrfs] [ 2280.786700] [<ffffffffa0230da5>] ? btrfs_wait_ordered_range+0x65/0x120 [btrfs] [ 2280.786756] [<ffffffffa0227e3e>] ? btrfs_sync_file+0x23e/0x2c0 [btrfs] [ 2280.786789] [<ffffffff81152af7>] ? SyS_msync+0x147/0x210 [ 2280.786819] [<ffffffff814c7b79>] ? system_call_fastpath+0x16/0x1b -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/ -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html