Toralf Förster
2014-Sep-03 17:17 UTC
INFO: task btrfs-transacti:2408 blocked for more than 120 seconds.
At a 32 bit stable Gentoo Linux I do have 2 BTRFS file systems :
$ mount | grep btrfs
/var/lib/portage.fs on /usr/portage type btrfs (rw,noatime,compress=lzo)
/var/lib/pkg.fs on /var/db/pkg type btrfs (rw,noatime,compress=lzo)
holding a lot of small Gentoo-package-Manager-related files. The first is
exported via NMFS so that my KVM can access that tree too.
Today I got a hang while upgrading a package at the host and one within the KVM
at the same time, syslog tells me:
Sep 3 19:10:57 n22 kernel: INFO: task btrfs-transacti:2408 blocked for more
than 120 seconds.
Sep 3 19:10:57 n22 kernel: Not tainted 3.16.1 #5
Sep 3 19:10:57 n22 kernel: "echo 0 >
/proc/sys/kernel/hung_task_timeout_secs" disables this message.
Sep 3 19:10:57 n22 kernel: btrfs-transacti D 00000000 0 2408 2
0x00000000
Sep 3 19:10:57 n22 kernel: edb15a34 00000086 c10c7efc 00000000 00000001
5197f8f9 00001fa0 c17bf880
Sep 3 19:10:57 n22 kernel: c17bf880 f3630880 f10167c0 c1099ed3 00000002
00000001 00000000 c10c7efc
Sep 3 19:10:57 n22 kernel: 118a2543 00000857 ffffffff 00000018 c24d94d3
002180b0 0062c84a abf93cc6
Sep 3 19:10:57 n22 kernel: Call Trace:
Sep 3 19:10:57 n22 kernel: [<c10c7efc>] ?
__delayacct_blkio_start+0x1c/0x20
Sep 3 19:10:57 n22 kernel: [<c1099ed3>] ? ktime_get_ts+0x83/0x180
Sep 3 19:10:57 n22 kernel: [<c10c7efc>] ?
__delayacct_blkio_start+0x1c/0x20
Sep 3 19:10:57 n22 kernel: [<c10f6ba0>] ? wait_on_page_read+0x50/0x50
Sep 3 19:10:57 n22 kernel: [<c14c4bc6>] io_schedule+0x86/0x100
Sep 3 19:10:57 n22 kernel: [<c10f6bad>] sleep_on_page+0xd/0x20
Sep 3 19:10:57 n22 kernel: [<c14c4ee1>] __wait_on_bit+0x51/0x80
Sep 3 19:10:57 n22 kernel: [<c10f6ba0>] ? wait_on_page_read+0x50/0x50
Sep 3 19:10:57 n22 kernel: [<c10f69f3>] wait_on_page_bit+0x83/0x90
Sep 3 19:10:57 n22 kernel: [<c107ce10>] ?
autoremove_wake_function+0x40/0x40
Sep 3 19:10:57 n22 kernel: [<c125869c>]
read_extent_buffer_pages+0x2dc/0x2f0
Sep 3 19:10:57 n22 kernel: [<c1229718>]
btree_read_extent_buffer_pages.constprop.50+0xc8/0x140
Sep 3 19:10:57 n22 kernel: [<c1228860>] ? free_root_pointers+0x50/0x50
Sep 3 19:10:57 n22 kernel: [<c122a6dc>] read_tree_block+0x3c/0x60
Sep 3 19:10:57 n22 kernel: [<c120ae31>]
read_block_for_search.isra.30+0x141/0x390
Sep 3 19:10:57 n22 kernel: [<c120cb67>] btrfs_search_slot+0x3a7/0x870
Sep 3 19:10:57 n22 kernel: [<c1213a92>]
lookup_inline_extent_backref+0x132/0x6e0
Sep 3 19:10:57 n22 kernel: [<c107222b>] ? update_curr+0xeb/0x1a0
Sep 3 19:10:57 n22 kernel: [<c107e7be>] ? cpuacct_charge+0x6e/0x90
Sep 3 19:10:57 n22 kernel: [<c12160cd>] __btrfs_free_extent+0x13d/0xd10
Sep 3 19:10:57 n22 kernel: [<c14c8652>] ? _raw_spin_unlock+0x22/0x30
Sep 3 19:10:57 n22 kernel: [<c121b9c7>] ?
__btrfs_run_delayed_refs+0x117/0x1260
Sep 3 19:10:57 n22 kernel: [<c121c187>]
__btrfs_run_delayed_refs+0x8d7/0x1260
Sep 3 19:10:57 n22 kernel: [<c1065849>] ? finish_task_switch+0x79/0x100
Sep 3 19:10:57 n22 kernel: [<c14c73ad>] ? mutex_unlock+0xd/0x10
Sep 3 19:10:57 n22 kernel: [<c12209c8>]
btrfs_run_delayed_refs.part.60+0x58/0x220
Sep 3 19:10:57 n22 kernel: [<c124e477>] ?
btrfs_run_ordered_operations+0x1b7/0x240
Sep 3 19:10:57 n22 kernel: [<c1220ba4>] btrfs_run_delayed_refs+0x14/0x30
Sep 3 19:10:57 n22 kernel: [<c1230f75>]
btrfs_commit_transaction+0x45/0xc70
Sep 3 19:10:57 n22 kernel: [<c1231c1e>] ? start_transaction+0x7e/0x5b0
Sep 3 19:10:57 n22 kernel: [<c122d3f5>] transaction_kthread+0x195/0x220
Sep 3 19:10:57 n22 kernel: [<c122d260>] ?
btrfs_cleanup_transaction+0x490/0x490
Sep 3 19:10:57 n22 kernel: [<c105d896>] kthread+0xa6/0xc0
Sep 3 19:10:57 n22 kernel: [<c14c8f01>] ret_from_kernel_thread+0x21/0x30
Sep 3 19:10:57 n22 kernel: [<c105d7f0>] ?
kthread_create_on_node+0x180/0x180
Sep 3 19:10:57 n22 kernel: 2 locks held by btrfs-transacti/2408:
Sep 3 19:10:57 n22 kernel: #0:
(&fs_info->transaction_kthread_mutex){......}, at: [<c122d367>]
transaction_kthread+0x107/0x220
Sep 3 19:10:57 n22 kernel: #1: (&head_ref->mutex){......}, at:
[<c128149f>] btrfs_delayed_ref_lock+0x2f/0x1f0
Just FWIW
--
Toralf
pgp key: 0076 E94E
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