On Mon, Apr 14, 2014 at 10:15:07AM +0800, Liu Bo wrote: > On Mon, Mar 24, 2014 at 06:49:56PM -0700, Marc MERLIN wrote: > > I had a tree with some amount of thousand files (less than 1 million) > > on top of md raid5. > > > > It took 18H to rm it in 3 tries: > > gargamel:/mnt/dshelf2/backup/polgara# time rm -rf current.todel/ > > real 1087m26.491s > > user 0m2.448s > > sys 4m42.012s > > > > gargamel:/mnt/dshelf2/backup/polgara# btrfs fi show /mnt/btrfs_pool2 > > Label: btrfs_pool2 uuid: cb9df6d3-a528-4afc-9a45-4fed5ec358d6 > > Total devices 1 FS bytes used 2.76TiB > > devid 1 size 7.28TiB used 3.43TiB path /dev/mapper/dshelf2 > > > > gargamel:/mnt/dshelf2/backup/polgara# btrfs fi df /mnt/btrfs_pool2 > > Data, single: total=3.28TiB, used=2.70TiB > > System, DUP: total=8.00MiB, used=384.00KiB > > System, single: total=4.00MiB, used=0.00 > > Metadata, DUP: total=73.50GiB, used=62.46GiB > > Metadata, single: total=8.00MiB, used=0.00 > > > > This is running from > > md8 : active raid5 sdf1[6] sdb1[5] sda1[3] sde1[2] sdd1[1] > > 7814045696 blocks super 1.2 level 5, 512k chunk, algorithm 2 [5/5] > > [UUUUU] > > bitmap: 0/15 pages [0KB], 65536KB chunk > > > > The filesystem is pretty new, it shouldn't be fragmented much. > > > > dmesg shows a bit of this: > > INFO: task rm:31885 blocked for more than 120 seconds. > > Not tainted 3.14.0-rc5-amd64-i915-preempt-20140216c #1 > > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message > > rm D ffff880117e5a940 0 31885 31280 0x20020080 > > ffff8800169f3d10 0000000000000086 ffff8800169f3fd8 ffff880117e5a410 > > 00000000000141c0 ffff880117e5a410 ffff88011d4f9e90 ffff88020c0109e8 > > 0000000000000000 ffff88020c010800 ffff8801b6df55a0 ffff8800169f3d20 > > Call Trace: > > [<ffffffff8160c331>] schedule+0x73/0x75 > > [<ffffffff8122a5f9>] wait_current_trans.isra.15+0x98/0xf4 > > [<ffffffff810850c9>] ? finish_wait+0x65/0x65 > > [<ffffffff8122ba9e>] start_transaction+0x48e/0x4f2 > > [<ffffffff8122bb1d>] btrfs_start_transaction+0x1b/0x1d > > [<ffffffff8122cab4>] __unlink_start_trans+0x24/0xaf > > [<ffffffff812327ab>] btrfs_unlink+0x28/0xa0 > > [<ffffffff8116176d>] vfs_unlink+0x90/0xdb > > [<ffffffff811618c0>] do_unlinkat+0x108/0x1da > > [<ffffffff810734c8>] ? mmdrop+0x11/0x20 > > [<ffffffff8115d2db>] ? path_put+0x1e/0x21 > > [<ffffffff811625c7>] SyS_unlinkat+0x22/0x2e > > [<ffffffff816171ac>] sysenter_dispatch+0x7/0x21 > > > > That said, it didn't happen much: > > [38077.054841] INFO: task btrfs-cleaner:3536 blocked for more than 120 > > seconds. > > [38077.521463] INFO: task rm:31885 blocked for more than 120 seconds. > > [38077.926399] INFO: task cp:26645 blocked for more than 120 seconds. > > [38078.346885] INFO: task btrfs:7430 blocked for more than 120 seconds. > > [38198.921768] INFO: task btrfs-cleaner:3536 blocked for more than 120 > > seconds. > > [38199.357367] INFO: task rm:31885 blocked for more than 120 seconds. > > [38199.753897] INFO: task cp:26645 blocked for more than 120 seconds. > > [38200.172729] INFO: task btrfs:7430 blocked for more than 120 seconds. > > [56696.271850] INFO: task btrfs-transacti:3537 blocked for more than 120 > > seconds. > > [56937.063142] INFO: task btrfs-cleaner:3536 blocked for more than 120 > > seconds. > > > > Of course, all of those are bad, but I'm unfortunately used to seeing them > > It wasn't hanging forever every few minutes, so it looks like it was just > > working > > very slowly. > > > > The problem does not seem to be just rm though, du is taking way way too > > long too. I started one, it's been running for 30mn now. > > Interestingly, sending ^C to that du takes 15 seconds to respond, so it > > seems that each system call is just slow. > > > > I checked that btrfs scrub is not running. > > What else can I check from here? > > Maybe 'sysrq+w' can give an answer? We need to find what blocks new > transaction.
Just misread this thread, sorry...I'm reading the following story of the thread. -liubo -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
