From: robbieko <robbieko@synology.com>
To: fdmanana@gmail.com
Cc: linux-btrfs@vger.kernel.org
Subject: Re: [PATCH] Btrfs: fix fsync deadlock in log_new_dir_dentries
Date: Tue, 11 Oct 2016 15:47:32 +0800 [thread overview]
Message-ID: <8444eb13f2a41d2a72ed0e7bd7cfc1f3@synology.com> (raw)
In-Reply-To: <CAL3q7H7=RC+OwbddA5dqr4u8AmKzKvuoYhkucOOXQpmhx7nBbA@mail.gmail.com>
Hi Filipe:
why did you replace the continue statement with a break statement:
because we released ahead of the path, it can not continue to use,
need to jump out, and then go to again.
supplement:
We found a fsync deadlock ie. 32021->32020->32028->14431->14436->32021,
the number id pid.
extent_buffer: start:207060992, len:16384
locker pid: 32020 read lock
wait pid: 32021 write lock
extent_buffer: start:14730821632, len:16384
locker pid: 32028 read lock
wait pid: 32020 write lock
extent_buffer: start:446503813120, len:16384
locker pid: 14431 write lock
wait pid: 32028 read lock
extent_buffer: start:446503845888, len: 16384
locker pid: 14436 write lock
wait pid: 14431 write lock
extent_buffer: start: 446504386560, len: 16384
locker pid: 32021 write lock
wait pid: 14436 write lock
Thanks.
Robbie Ko
Filipe Manana 於 2016-10-07 18:46 寫到:
> On Fri, Oct 7, 2016 at 11:43 AM, robbieko <robbieko@synology.com>
> wrote:
>> Hi Filipe,
>>
>> I am sorry, I express not clear enough.
>> This number is pid, and the above are their call trace respectively.
>
> And why did you replace the continue statement with a break statement?
>
> Also please avoid mixing inline replies with top posting, it just
> breaks the thread.
>
> thanks
>
>>
>> Thanks.
>> robbieko
>>
>> Filipe Manana <fdmanana@gmail.com> 於 2016-10-07 18:23 寫道：
>>
>> On Fri, Oct 7, 2016 at 11:05 AM, robbieko <robbieko@synology.com>
>> wrote:
>>> From: Robbie Ko <robbieko@synology.com>
>>>
>>> We found a fsync deadlock ie.
>>> 32021->32020->32028->14431->14436->32021,
>>> in log_new_dir_dentries, because btrfs_search_forward get path lock,
>>> then
>>> call btrfs_iget will get another extent_buffer lock, maybe occur
>>> deadlock.
>>
>> What are those numbers? Are they inode numbers?
>> If so you're suggesting a deadlock due to recursive logging of the
>> same
>> inode.
>> However the trace below, and the code change, has nothing to do with
>> that.
>> It's just about btrfs_iget trying to do a search on a btree and
>> attempting to read lock some node/leaf that already has a write lock
>> acquired previously by the same task.
>>
>> Please be more clear on your change logs.
>>
>>
>>>
>>> we can release path before call btrfs_iget, avoid deadlock occur.
>>>
>>> some process call trace like below:
>>> [ 4077.478852] kworker/u24:10 D ffff88107fc90640 0 14431 2
>>> 0x00000000
>>> [ 4077.486752] Workqueue: btrfs-endio-write btrfs_endio_write_helper
>>> [btrfs]
>>> [ 4077.494346] ffff880ffa56bad0 0000000000000046 0000000000009000
>>> ffff880ffa56bfd8
>>> [ 4077.502629] ffff880ffa56bfd8 ffff881016ce21c0 ffffffffa06ecb26
>>> ffff88101a5d6138
>>> [ 4077.510915] ffff880ebb5173b0 ffff880ffa56baf8 ffff880ebb517410
>>> ffff881016ce21c0
>>> [ 4077.519202] Call Trace:
>>> [ 4077.528752] [<ffffffffa06ed5ed>] ? btrfs_tree_lock+0xdd/0x2f0
>>> [btrfs]
>>> [ 4077.536049] [<ffffffff81053680>] ? wake_up_atomic_t+0x30/0x30
>>> [ 4077.542574] [<ffffffffa068cc1f>] ? btrfs_search_slot+0x79f/0xb10
>>> [btrfs]
>>> [ 4077.550171] [<ffffffffa06a5073>] ?
>>> btrfs_lookup_file_extent+0x33/0x40
>>> [btrfs]
>>> [ 4077.558252] [<ffffffffa06c600b>] ?
>>> __btrfs_drop_extents+0x13b/0xdf0
>>> [btrfs]
>>> [ 4077.566140] [<ffffffffa06fc9e2>] ?
>>> add_delayed_data_ref+0xe2/0x150
>>> [btrfs]
>>> [ 4077.573928] [<ffffffffa06fd629>] ?
>>> btrfs_add_delayed_data_ref+0x149/0x1d0 [btrfs]
>>> [ 4077.582399] [<ffffffffa06cf3c0>] ? __set_extent_bit+0x4c0/0x5c0
>>> [btrfs]
>>> [ 4077.589896] [<ffffffffa06b4a64>] ?
>>> insert_reserved_file_extent.constprop.75+0xa4/0x320 [btrfs]
>>> [ 4077.599632] [<ffffffffa06b206d>] ? start_transaction+0x8d/0x470
>>> [btrfs]
>>> [ 4077.607134] [<ffffffffa06bab57>] ?
>>> btrfs_finish_ordered_io+0x2e7/0x600
>>> [btrfs]
>>> [ 4077.615329] [<ffffffff8104cbc2>] ? process_one_work+0x142/0x3d0
>>> [ 4077.622043] [<ffffffff8104d729>] ? worker_thread+0x109/0x3b0
>>> [ 4077.628459] [<ffffffff8104d620>] ?
>>> manage_workers.isra.26+0x270/0x270
>>> [ 4077.635759] [<ffffffff81052b0f>] ? kthread+0xaf/0xc0
>>> [ 4077.641404] [<ffffffff81052a60>] ?
>>> kthread_create_on_node+0x110/0x110
>>> [ 4077.648696] [<ffffffff814a9ac8>] ? ret_from_fork+0x58/0x90
>>> [ 4077.654926] [<ffffffff81052a60>] ?
>>> kthread_create_on_node+0x110/0x110
>>>
>>> [ 4078.358087] kworker/u24:15 D ffff88107fcd0640 0 14436 2
>>> 0x00000000
>>> [ 4078.365981] Workqueue: btrfs-endio-write btrfs_endio_write_helper
>>> [btrfs]
>>> [ 4078.373574] ffff880ffa57fad0 0000000000000046 0000000000009000
>>> ffff880ffa57ffd8
>>> [ 4078.381864] ffff880ffa57ffd8 ffff88103004d0a0 ffffffffa06ecb26
>>> ffff88101a5d6138
>>> [ 4078.390163] ffff880fbeffc298 ffff880ffa57faf8 ffff880fbeffc2f8
>>> ffff88103004d0a0
>>> [ 4078.398466] Call Trace:
>>> [ 4078.408019] [<ffffffffa06ed5ed>] ? btrfs_tree_lock+0xdd/0x2f0
>>> [btrfs]
>>> [ 4078.415322] [<ffffffff81053680>] ? wake_up_atomic_t+0x30/0x30
>>> [ 4078.421844] [<ffffffffa068cc1f>] ? btrfs_search_slot+0x79f/0xb10
>>> [btrfs]
>>> [ 4078.429438] [<ffffffffa06a5073>] ?
>>> btrfs_lookup_file_extent+0x33/0x40
>>> [btrfs]
>>> [ 4078.437518] [<ffffffffa06c600b>] ?
>>> __btrfs_drop_extents+0x13b/0xdf0
>>> [btrfs]
>>> [ 4078.445404] [<ffffffffa06fc9e2>] ?
>>> add_delayed_data_ref+0xe2/0x150
>>> [btrfs]
>>> [ 4078.453194] [<ffffffffa06fd629>] ?
>>> btrfs_add_delayed_data_ref+0x149/0x1d0 [btrfs]
>>> [ 4078.461663] [<ffffffffa06cf3c0>] ? __set_extent_bit+0x4c0/0x5c0
>>> [btrfs]
>>> [ 4078.469161] [<ffffffffa06b4a64>] ?
>>> insert_reserved_file_extent.constprop.75+0xa4/0x320 [btrfs]
>>> [ 4078.478893] [<ffffffffa06b206d>] ? start_transaction+0x8d/0x470
>>> [btrfs]
>>> [ 4078.486388] [<ffffffffa06bab57>] ?
>>> btrfs_finish_ordered_io+0x2e7/0x600
>>> [btrfs]
>>> [ 4078.494561] [<ffffffff8104cbc2>] ? process_one_work+0x142/0x3d0
>>> [ 4078.501278] [<ffffffff8104a507>] ?
>>> pwq_activate_delayed_work+0x27/0x40
>>> [ 4078.508673] [<ffffffff8104d729>] ? worker_thread+0x109/0x3b0
>>> [ 4078.515098] [<ffffffff8104d620>] ?
>>> manage_workers.isra.26+0x270/0x270
>>> [ 4078.522396] [<ffffffff81052b0f>] ? kthread+0xaf/0xc0
>>> [ 4078.528032] [<ffffffff81052a60>] ?
>>> kthread_create_on_node+0x110/0x110
>>> [ 4078.535325] [<ffffffff814a9ac8>] ? ret_from_fork+0x58/0x90
>>> [ 4078.541552] [<ffffffff81052a60>] ?
>>> kthread_create_on_node+0x110/0x110
>>>
>>> [ 4079.355824] user-space-program D ffff88107fd30640 0 32020
>>> 1
>>> 0x00000000
>>> [ 4079.363716] ffff880eae8eba10 0000000000000086 0000000000009000
>>> ffff880eae8ebfd8
>>> [ 4079.372003] ffff880eae8ebfd8 ffff881016c162c0 ffffffffa06ecb26
>>> ffff88101a5d6138
>>> [ 4079.380294] ffff880fbed4b4c8 ffff880eae8eba38 ffff880fbed4b528
>>> ffff881016c162c0
>>> [ 4079.388586] Call Trace:
>>> [ 4079.398134] [<ffffffffa06ed595>] ? btrfs_tree_lock+0x85/0x2f0
>>> [btrfs]
>>> [ 4079.405431] [<ffffffff81053680>] ? wake_up_atomic_t+0x30/0x30
>>> [ 4079.411955] [<ffffffffa06876fb>] ? btrfs_lock_root_node+0x2b/0x40
>>> [btrfs]
>>> [ 4079.419644] [<ffffffffa068ce83>] ? btrfs_search_slot+0xa03/0xb10
>>> [btrfs]
>>> [ 4079.427237] [<ffffffffa06aba52>] ?
>>> btrfs_buffer_uptodate+0x52/0x70
>>> [btrfs]
>>> [ 4079.435041] [<ffffffffa0689b60>] ?
>>> generic_bin_search.constprop.38+0x80/0x190 [btrfs]
>>> [ 4079.443897] [<ffffffffa068ea44>] ?
>>> btrfs_insert_empty_items+0x74/0xd0
>>> [btrfs]
>>> [ 4079.451975] [<ffffffffa072c443>] ? copy_items+0x128/0x850 [btrfs]
>>> [ 4079.458890] [<ffffffffa072da10>] ? btrfs_log_inode+0x629/0xbf3
>>> [btrfs]
>>> [ 4079.466292] [<ffffffffa06f34a1>] ?
>>> btrfs_log_inode_parent+0xc61/0xf30
>>> [btrfs]
>>> [ 4079.474373] [<ffffffffa06f45a9>] ?
>>> btrfs_log_dentry_safe+0x59/0x80
>>> [btrfs]
>>> [ 4079.482161] [<ffffffffa06c298d>] ? btrfs_sync_file+0x20d/0x330
>>> [btrfs]
>>> [ 4079.489558] [<ffffffff8112777c>] ? do_fsync+0x4c/0x80
>>> [ 4079.495300] [<ffffffff81127a0a>] ? SyS_fdatasync+0xa/0x10
>>> [ 4079.501422] [<ffffffff814a9b72>] ? system_call_fastpath+0x16/0x1b
>>>
>>> [ 4079.508334] user-space-program D ffff88107fc30640 0 32021
>>> 1
>>> 0x00000004
>>> [ 4079.516226] ffff880eae8efbf8 0000000000000086 0000000000009000
>>> ffff880eae8effd8
>>> [ 4079.524513] ffff880eae8effd8 ffff881030279610 ffffffffa06ecb26
>>> ffff88101a5d6138
>>> [ 4079.532802] ffff880ebb671d88 ffff880eae8efc20 ffff880ebb671de8
>>> ffff881030279610
>>> [ 4079.541092] Call Trace:
>>> [ 4079.550642] [<ffffffffa06ed595>] ? btrfs_tree_lock+0x85/0x2f0
>>> [btrfs]
>>> [ 4079.557941] [<ffffffff81053680>] ? wake_up_atomic_t+0x30/0x30
>>> [ 4079.564463] [<ffffffffa068cc1f>] ? btrfs_search_slot+0x79f/0xb10
>>> [btrfs]
>>> [ 4079.572058] [<ffffffffa06bb7d8>] ?
>>> btrfs_truncate_inode_items+0x168/0xb90 [btrfs]
>>> [ 4079.580526] [<ffffffffa06b04be>] ?
>>> join_transaction.isra.15+0x1e/0x3a0
>>> [btrfs]
>>> [ 4079.588701] [<ffffffffa06b206d>] ? start_transaction+0x8d/0x470
>>> [btrfs]
>>> [ 4079.596196] [<ffffffffa0690ac6>] ? block_rsv_add_bytes+0x16/0x50
>>> [btrfs]
>>> [ 4079.603789] [<ffffffffa06bc2e9>] ? btrfs_truncate+0xe9/0x2e0
>>> [btrfs]
>>> [ 4079.610994] [<ffffffffa06bd00b>] ? btrfs_setattr+0x30b/0x410
>>> [btrfs]
>>> [ 4079.618197] [<ffffffff81117c1c>] ? notify_change+0x1dc/0x680
>>> [ 4079.624625] [<ffffffff8123c8a4>] ? aa_path_perm+0xd4/0x160
>>> [ 4079.630854] [<ffffffff810f4fcb>] ? do_truncate+0x5b/0x90
>>> [ 4079.636889] [<ffffffff810f59fa>] ?
>>> do_sys_ftruncate.constprop.15+0x10a/0x160
>>> [ 4079.644869] [<ffffffff8110d87b>] ? SyS_fcntl+0x5b/0x570
>>> [ 4079.650805] [<ffffffff814a9b72>] ? system_call_fastpath+0x16/0x1b
>>>
>>> [ 4080.410607] user-space-program D ffff88107fc70640 0 32028
>>> 12639
>>> 0x00000004
>>> [ 4080.418489] ffff880eaeccbbe0 0000000000000086 0000000000009000
>>> ffff880eaeccbfd8
>>> [ 4080.426778] ffff880eaeccbfd8 ffff880f317ef1e0 ffffffffa06ecb26
>>> ffff88101a5d6138
>>> [ 4080.435067] ffff880ef7e93928 ffff880f317ef1e0 ffff880eaeccbc08
>>> ffff880f317ef1e0
>>> [ 4080.443353] Call Trace:
>>> [ 4080.452920] [<ffffffffa06ed15d>] ?
>>> btrfs_tree_read_lock+0xdd/0x190
>>> [btrfs]
>>> [ 4080.460703] [<ffffffff81053680>] ? wake_up_atomic_t+0x30/0x30
>>> [ 4080.467225] [<ffffffffa06876bb>] ?
>>> btrfs_read_lock_root_node+0x2b/0x40
>>> [btrfs]
>>> [ 4080.475400] [<ffffffffa068cc81>] ? btrfs_search_slot+0x801/0xb10
>>> [btrfs]
>>> [ 4080.482994] [<ffffffffa06b2df0>] ?
>>> btrfs_clean_one_deleted_snapshot+0xe0/0xe0 [btrfs]
>>> [ 4080.491857] [<ffffffffa06a70a6>] ? btrfs_lookup_inode+0x26/0x90
>>> [btrfs]
>>> [ 4080.499353] [<ffffffff810ec42f>] ? kmem_cache_alloc+0xaf/0xc0
>>> [ 4080.505879] [<ffffffffa06bd905>] ? btrfs_iget+0xd5/0x5d0 [btrfs]
>>> [ 4080.512696] [<ffffffffa06caf04>] ? btrfs_get_token_64+0x104/0x120
>>> [btrfs]
>>> [ 4080.520387] [<ffffffffa06f341f>] ?
>>> btrfs_log_inode_parent+0xbdf/0xf30
>>> [btrfs]
>>> [ 4080.528469] [<ffffffffa06f45a9>] ?
>>> btrfs_log_dentry_safe+0x59/0x80
>>> [btrfs]
>>> [ 4080.536258] [<ffffffffa06c298d>] ? btrfs_sync_file+0x20d/0x330
>>> [btrfs]
>>> [ 4080.543657] [<ffffffff8112777c>] ? do_fsync+0x4c/0x80
>>> [ 4080.549399] [<ffffffff81127a0a>] ? SyS_fdatasync+0xa/0x10
>>> [ 4080.555534] [<ffffffff814a9b72>] ? system_call_fastpath+0x16/0x1b
>>>
>>> Signed-off-by: Robbie Ko <robbieko@synology.com>
>>> ---
>>> fs/btrfs/tree-log.c | 4 ++--
>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
>>> index ef9c55b..9913084 100644
>>> --- a/fs/btrfs/tree-log.c
>>> +++ b/fs/btrfs/tree-log.c
>>> @@ -5213,6 +5213,7 @@ process_leaf:
>>> if (di_key.type == BTRFS_ROOT_ITEM_KEY)
>>> continue;
>>>
>>> + btrfs_release_path(path);
>>> di_inode = btrfs_iget(root->fs_info->sb,
>>> &di_key,
>>> root, NULL);
>>> if (IS_ERR(di_inode)) {
>>> @@ -5222,13 +5223,12 @@ process_leaf:
>>>
>>> if (btrfs_inode_in_log(di_inode,
>>> trans->transid))
>>> {
>>> iput(di_inode);
>>> - continue;
>>> + break;
>>
>> Why the break instead of continue? This seems totally unrelated to the
>> deadlock on a leaf/node and incorrect.
>>
>> thanks
>>
>>> }
>>>
>>> ctx->log_new_dentries = false;
>>> if (type == BTRFS_FT_DIR || type ==
>>> BTRFS_FT_SYMLINK)
>>> log_mode = LOG_INODE_ALL;
>>> - btrfs_release_path(path);
>>> ret = btrfs_log_inode(trans, root, di_inode,
>>> log_mode, 0, LLONG_MAX,
>>> ctx);
>>> if (!ret &&
>>> --
>>> 1.9.1
>>>
>>> --
>>> 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
>>
>>
>>
>> --
>> Filipe David Manana,
>>
>> "People will forget what you said,
>> people will forget what you did,
>> but people will never forget how you made them feel."
next prev parent reply other threads:[~2016-10-11 7:47 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-07 10:05 [PATCH] Btrfs: fix fsync deadlock in log_new_dir_dentries robbieko
2016-10-07 10:23 ` Filipe Manana
[not found] ` <e077183a-e7b4-43c1-bb8d-a1cf900072fe@Mail>
2016-10-07 10:46 ` Filipe Manana
2016-10-11 7:47 ` robbieko [this message]
2016-10-12 9:04 ` Filipe Manana
-- strict thread matches above, loose matches on Subject: below --
2016-10-28 2:48 robbieko
2016-11-30 16:25 ` Filipe Manana
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