From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Martin Ziegler , Jiri Kosina , David Sterba , Chris Mason Subject: [PATCH 4.4 023/137] Revert "btrfs: clear PF_NOFREEZE in cleaner_kthread()" Date: Tue, 23 Feb 2016 19:32:34 -0800 Message-Id: <20160224033418.058525771@linuxfoundation.org> In-Reply-To: <20160224033417.270530882@linuxfoundation.org> References: <20160224033417.270530882@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Sterba commit 80ad623edd2d0ccb47d85357ee31c97e6c684e82 upstream. This reverts commit 696249132158014d594896df3a81390616069c5c. The cleaner thread can block freezing when there's a snapshot cleaning in progress and the other threads get suspended first. From the logs provided by Martin we're waiting for reading extent pages: kernel: PM: Syncing filesystems ... done. kernel: Freezing user space processes ... (elapsed 0.015 seconds) done. kernel: Freezing remaining freezable tasks ... kernel: Freezing of tasks failed after 20.003 seconds (1 tasks refusing to freeze, wq_busy=0): kernel: btrfs-cleaner D ffff88033dd13bc0 0 152 2 0x00000000 kernel: ffff88032ebc2e00 ffff88032e750000 ffff88032e74fa50 7fffffffffffffff kernel: ffffffff814a58df 0000000000000002 ffffea000934d580 ffffffff814a5451 kernel: 7fffffffffffffff ffffffff814a6e8f 0000000000000000 0000000000000020 kernel: Call Trace: kernel: [] ? bit_wait+0x2c/0x2c kernel: [] ? schedule+0x6f/0x7c kernel: [] ? schedule_timeout+0x2f/0xd8 kernel: [] ? timekeeping_get_ns+0xa/0x2e kernel: [] ? ktime_get+0x36/0x44 kernel: [] ? io_schedule_timeout+0x94/0xf2 kernel: [] ? io_schedule_timeout+0x94/0xf2 kernel: [] ? bit_wait_io+0x2c/0x30 kernel: [] ? __wait_on_bit+0x41/0x73 kernel: [] ? wait_on_page_bit+0x6d/0x72 kernel: [] ? autoremove_wake_function+0x2a/0x2a kernel: [] ? read_extent_buffer_pages+0x1bd/0x203 kernel: [] ? free_root_pointers+0x4c/0x4c kernel: [] ? btree_read_extent_buffer_pages.constprop.57+0x5a/0xe9 kernel: [] ? read_tree_block+0x2d/0x45 kernel: [] ? read_block_for_search.isra.34+0x22a/0x26b kernel: [] ? btrfs_set_path_blocking+0x1e/0x4a kernel: [] ? btrfs_search_slot+0x648/0x736 kernel: [] ? btrfs_lookup_extent_info+0xb7/0x2c7 kernel: [] ? walk_down_proc+0x9c/0x1ae kernel: [] ? walk_down_tree+0x40/0xa4 kernel: [] ? btrfs_drop_snapshot+0x2da/0x664 kernel: [] ? finish_task_switch+0x126/0x167 kernel: [] ? btrfs_clean_one_deleted_snapshot+0xa6/0xb0 kernel: [] ? cleaner_kthread+0x13e/0x17b kernel: [] ? btrfs_item_end+0x33/0x33 kernel: [] ? kthread+0x95/0x9d kernel: [] ? kthread_parkme+0x16/0x16 kernel: [] ? ret_from_fork+0x3f/0x70 kernel: [] ? kthread_parkme+0x16/0x16 As this affects a released kernel (4.4) we need a minimal fix for stable kernels. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=108361 Reported-by: Martin Ziegler CC: Jiri Kosina Signed-off-by: David Sterba Signed-off-by: Chris Mason Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/disk-io.c | 1 - 1 file changed, 1 deletion(-) --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1762,7 +1762,6 @@ static int cleaner_kthread(void *arg) int again; struct btrfs_trans_handle *trans; - set_freezable(); do { again = 0;