On Fri, Oct 7, 2016 at 11:05 AM, robbieko <robbi...@synology.com> wrote: > From: Robbie Ko <robbi...@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 <robbi...@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 majord...@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." -- 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