On Fri, Aug 7, 2015 at 5:01 AM, Liu Bo <bo.li....@oracle.com> wrote:
> Hi,
>
> On Wed, Aug 05, 2015 at 10:28:05AM +0200, Elias Probst wrote:
>> I can reproduce a hard btrfs lockup (process issuing the ioctl() is in
>> D-state, same goes for btrfs-transacti process) on Kernel 4.2.0-rc5.
>>
>> I had the same issue on 4.1, so it's unlikely a regression introduced in
>> 4.2.
>>
>> ## With the following steps, I can reproduce the problem:
>>
>> 1. Create a new clean btrfs volume for /var/lib/machines
>> machinectl set-limit 6G
>>
>> 2. Paste this to /tmp/yum.conf
>> [main]
>> reposdir=/dev/null
>> gpgcheck=0
>> logfile=/var/log/yum.log
>> installroot=/var/lib/machines/centos7.1-base
>> assumeyes=1
>>
>> [base]
>> name=CentOS 7.1.1503 - x86_64
>> baseurl=http://mirror.centos.org/centos/7.1.1503/os/x86_64/
>> enabled=1
>>
>> 3. Bootstrap a CentOS 7.1 base image
>> /usr/bin/yum -c /tmp/yum.conf groupinstall Base
>>
>> 4. Start an ephemeral systemd-nspawn container based on 'centos7.1-base'
>> strace -o /tmp/systemd-nspawn.out -s 500 -f systemd-nspawn -xbD
>> /var/lib/machines/centos7.1-base/
>>
>>
>> `systemd-nspawn` will now just hang forever.
>> I couldn't come up yet with a shorter/more low-level way to reproduce this
>> as I lack quite a bit of btrfs experience.
>
> Thank you for reporting this.
>
> Could you do 'echo w > /proc/sysrq-trigger' to gather the whole hang call
> stack?
>
> Here's a quick patch that may address your problem, can you give it a shot
> after
> getting sysrq-w output?
Hi Liu,
Can you please send the patch git formatted, in a dedicated thread,
with a change log, signed-off-by tag, etc, so that it hopefully gets
in to 4.4? You can also add my Reviewed-by: Filipe Manana
<fdman...@suse.com>
Thanks
>
> Thanks,
>
> -liubo
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 0770c91..b52bd66 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -3478,6 +3478,22 @@ process_slot:
> drop_start = new_key.offset;
>
> /*
> + * We need to look up the roots that point at
> + * this bytenr and see if the new root does. If
> + * it does not we need to make sure we update
> + * quotas appropriately.
> + */
> + if (disko && root != BTRFS_I(src)->root &&
> + disko != last_disko) {
> + no_quota = check_ref(trans, root,
> + disko);
> + if (no_quota < 0) {
> + ret = no_quota;
> + goto out;
> + }
> + }
> +
> + /*
> * 1 - adjusting old extent (we may have to * split
> it)
> * 1 - add new extent
> * 1 - inode update
> @@ -3544,27 +3560,6 @@ process_slot:
> btrfs_set_file_extent_num_bytes(leaf, extent,
> datal);
>
> - /*
> - * We need to look up the roots that point at
> - * this bytenr and see if the new root does.
> If
> - * it does not we need to make sure we update
> - * quotas appropriately. -
> */
> - if (disko && root != BTRFS_I(src)->root &&
> - disko != last_disko) {
> - no_quota = check_ref(trans, root,
> - disko);
> - if (no_quota < 0) {
> - btrfs_abort_transaction(trans,
> - root,
> - ret);
> - btrfs_end_transaction(trans,
> - root);
> - ret = no_quota;
> - goto out;
> - }
> - }
> -
> if (disko) {
> inode_add_bytes(inode, datal);
> ret = btrfs_inc_extent_ref(trans,
> root,
>
>
>>
>> ## Results:
>>
>> - Last 'strace' lines
>> 6095 fchown(16, 0, 0) = 0
>> 6095 fchmod(16, 0755) = 0
>> 6095 utimensat(16, NULL, {{1402362275, 0}, {1438761285, 819041906}}, 0) = 0
>> 6095 flistxattr(15, "", 100) = 0
>> 6095 getdents(15, /* 3 entries */, 32768) = 80
>> 6095 newfstatat(15, "coreutils.mo", {st_mode=S_IFREG|0644, st_size=357263,
>> ...}, AT_SYMLINK_NOFOLLOW) = 0
>> 6095 openat(15, "coreutils.mo", O_RDONLY|O_NOCTTY|O_NOFOLLOW|O_CLOEXEC) = 17
>> 6095 openat(16, "coreutils.mo",
>> O_WRONLY|O_CREAT|O_EXCL|O_NOCTTY|O_NOFOLLOW|O_CLOEXEC, 0644) = 18
>> 6095 fstat(18, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0
>> 6095 ioctl(18, BTRFS_IOC_CLONE
>>
>> - call trace in Kernel journal:
>> Aug 05 10:10:03 moria kernel: INFO: task btrfs-transacti:4175 blocked for
>> more than 120 seconds.
>> Aug 05 10:10:03 moria kernel: Tainted: G O 4.2.0-rc5 #2
>> Aug 05 10:10:03 moria kernel: "echo 0 >
>> /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>> Aug 05 10:10:03 moria kernel: btrfs-transacti D ffff8800b13279f8 0 4175
>> 2 0x00080080
>> Aug 05 10:10:03 moria kernel: ffff8800b13279f8 ffff88018fd3a380
>> ffff8800ab4521c0 0000000000000246
>> Aug 05 10:10:03 moria kernel: ffff8800b1328000 ffff88018d5c8518
>> ffff88018debdba0 ffff880232d64990
>> Aug 05 10:10:03 moria kernel: 0000000000000197 ffff8800b1327a18
>> ffffffff86999201 0000000000000000
>> Aug 05 10:10:03 moria kernel: Call Trace:
>> Aug 05 10:10:03 moria kernel: [<ffffffff86999201>] schedule+0x74/0x83
>> Aug 05 10:10:03 moria kernel: [<ffffffff863ef8f0>]
>> btrfs_tree_lock+0xa7/0x1b7
>> Aug 05 10:10:03 moria kernel: [<ffffffff86137ed7>] ? wait_woken+0x74/0x74
>> Aug 05 10:10:03 moria kernel: [<ffffffff8639d30f>]
>> push_leaf_right+0x9a/0x19f
>> Aug 05 10:10:03 moria kernel: [<ffffffff8639dd9b>] split_leaf+0x100/0x63f
>> Aug 05 10:10:03 moria kernel: [<ffffffff86398f09>] ?
>> leaf_space_used+0xbb/0xea
>> Aug 05 10:10:03 moria kernel: [<ffffffff863efa61>] ?
>> btrfs_set_lock_blocking_rw+0x52/0x95
>> Aug 05 10:10:03 moria kernel: [<ffffffff8639ea46>]
>> btrfs_search_slot+0x76c/0x8b3
>> Aug 05 10:10:03 moria kernel: [<ffffffff863a0107>]
>> btrfs_insert_empty_items+0x58/0xa3
>> Aug 05 10:10:03 moria kernel: [<ffffffff8640805a>]
>> btrfs_insert_delayed_items+0x7f/0x3bb
>> Aug 05 10:10:03 moria kernel: [<ffffffff8640842e>]
>> __btrfs_run_delayed_items+0x98/0x1c0
>> Aug 05 10:10:03 moria kernel: [<ffffffff86408739>]
>> btrfs_run_delayed_items+0xc/0xe
>> Aug 05 10:10:03 moria kernel: [<ffffffff863bdc50>]
>> btrfs_commit_transaction+0x298/0xb66
>> Aug 05 10:10:03 moria kernel: [<ffffffff863be8d0>] ?
>> start_transaction+0x3b2/0x535
>> Aug 05 10:10:03 moria kernel: [<ffffffff863b9cd9>]
>> transaction_kthread+0x100/0x1d6
>> Aug 05 10:10:03 moria kernel: [<ffffffff863b9bd9>] ?
>> btrfs_cleanup_transaction+0x49f/0x49f
>> Aug 05 10:10:03 moria kernel: [<ffffffff8611eca9>] kthread+0xcd/0xd5
>> Aug 05 10:10:03 moria kernel: [<ffffffff8611ebdc>] ?
>> kthread_create_on_node+0x17d/0x17d
>> Aug 05 10:10:03 moria kernel: [<ffffffff8699d29f>] ret_from_fork+0x3f/0x70
>> Aug 05 10:10:03 moria kernel: [<ffffffff8611ebdc>] ?
>> kthread_create_on_node+0x17d/0x17d
>> Aug 05 10:10:03 moria kernel: INFO: task systemd-nspawn:6095 blocked for
>> more than 120 seconds.
>> Aug 05 10:10:03 moria kernel: Tainted: G O 4.2.0-rc5 #2
>> Aug 05 10:10:03 moria kernel: "echo 0 >
>> /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>> Aug 05 10:10:03 moria kernel: systemd-nspawn D ffff88019f3e3668 0 6095
>> 6090 0x00080083
>> Aug 05 10:10:03 moria kernel: ffff88019f3e3668 ffffffff86e5d480
>> ffff88018fd3a380 0000000000000246
>> Aug 05 10:10:03 moria kernel: ffff88019f3e4000 ffff88018debdc08
>> ffff88018fd3a380 ffff88019f3e36b8
>> Aug 05 10:10:03 moria kernel: ffff88018fd3a380 ffff88019f3e3688
>> ffffffff86999201 0000000000000000
>> Aug 05 10:10:03 moria kernel: Call Trace:
>> Aug 05 10:10:03 moria kernel: [<ffffffff86999201>] schedule+0x74/0x83
>> Aug 05 10:10:03 moria kernel: [<ffffffff863ef64c>]
>> btrfs_tree_read_lock+0xc0/0xea
>> Aug 05 10:10:03 moria kernel: [<ffffffff86137ed7>] ? wait_woken+0x74/0x74
>> Aug 05 10:10:03 moria kernel: [<ffffffff8639f0a7>]
>> btrfs_search_old_slot+0x51a/0x810
>> Aug 05 10:10:03 moria kernel: [<ffffffff863a129b>]
>> btrfs_next_old_leaf+0xdf/0x3ce
>> Aug 05 10:10:03 moria kernel: [<ffffffff86413a00>] ?
>> ulist_add_merge+0x1b/0x127
>> Aug 05 10:10:03 moria kernel: [<ffffffff86411688>]
>> __resolve_indirect_refs+0x62a/0x667
>> Aug 05 10:10:03 moria kernel: [<ffffffff863ef546>] ?
>> btrfs_clear_lock_blocking_rw+0x78/0xbe
>> Aug 05 10:10:03 moria kernel: [<ffffffff864122d3>]
>> find_parent_nodes+0xaf3/0xfc6
>> Aug 05 10:10:03 moria kernel: [<ffffffff86412838>]
>> __btrfs_find_all_roots+0x92/0xf0
>> Aug 05 10:10:03 moria kernel: [<ffffffff864128f2>]
>> btrfs_find_all_roots+0x45/0x65
>> Aug 05 10:10:03 moria kernel: [<ffffffff8639a75b>] ?
>> btrfs_get_tree_mod_seq+0x2b/0x88
>> Aug 05 10:10:03 moria kernel: [<ffffffff863e852e>] check_ref+0x64/0xc4
>> Aug 05 10:10:03 moria kernel: [<ffffffff863e9e01>] btrfs_clone+0x66e/0xb5d
>> Aug 05 10:10:03 moria kernel: [<ffffffff863ea77f>]
>> btrfs_ioctl_clone+0x48f/0x5bb
>> Aug 05 10:10:03 moria kernel: [<ffffffff86048a68>] ?
>> native_sched_clock+0x28/0x77
>> Aug 05 10:10:03 moria kernel: [<ffffffff863ed9b0>] btrfs_ioctl+0xabc/0x25cb
>> Aug 05 10:10:03 moria kernel: [<ffffffff86998f25>] ? __schedule+0x590/0x7f8
>> Aug 05 10:10:03 moria kernel: [<ffffffff86999201>] ? schedule+0x74/0x83
>> Aug 05 10:10:03 moria kernel: [<ffffffff86111b2e>] ? ptrace_stop+0x227/0x236
>> Aug 05 10:10:03 moria kernel: [<ffffffff8612ba10>] ?
>> account_system_time+0xf2/0x10f
>> Aug 05 10:10:03 moria kernel: [<ffffffff86111bbc>] ?
>> ptrace_do_notify+0x7f/0x8c
>> Aug 05 10:10:03 moria kernel: [<ffffffff861fff2e>] do_vfs_ioctl+0x369/0x423
>> Aug 05 10:10:03 moria kernel: [<ffffffff8617c29f>] ?
>> __audit_syscall_entry+0xba/0xdc
>> Aug 05 10:10:03 moria kernel: [<ffffffff86200021>] SyS_ioctl+0x39/0x61
>> Aug 05 10:10:03 moria kernel: [<ffffffff8699cfd5>] tracesys_phase2+0x84/0x89
>>
>
>
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--
Filipe David Manana,
"Reasonable men adapt themselves to the world.
Unreasonable men adapt the world to themselves.
That's why all progress depends on unreasonable men."
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