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From: <gregkh@linuxfoundation.org>
To: dsterba@suse.com, clm@fb.com, gregkh@linuxfoundation.org,
	jkosina@suse.cz, ziegler@uni-freiburg.de
Cc: <stable@vger.kernel.org>, <stable-commits@vger.kernel.org>
Subject: Patch "Revert "btrfs: clear PF_NOFREEZE in cleaner_kthread()"" has been added to the 4.4-stable tree
Date: Tue, 23 Feb 2016 19:24:53 -0800	[thread overview]
Message-ID: <145628429319711@kroah.com> (raw)


This is a note to let you know that I've just added the patch titled

    Revert "btrfs: clear PF_NOFREEZE in cleaner_kthread()"

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     revert-btrfs-clear-pf_nofreeze-in-cleaner_kthread.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 80ad623edd2d0ccb47d85357ee31c97e6c684e82 Mon Sep 17 00:00:00 2001
From: David Sterba <dsterba@suse.com>
Date: Mon, 25 Jan 2016 11:02:06 +0100
Subject: Revert "btrfs: clear PF_NOFREEZE in cleaner_kthread()"

From: David Sterba <dsterba@suse.com>

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: [<ffffffff814a58df>] ? bit_wait+0x2c/0x2c
kernel: [<ffffffff814a5451>] ? schedule+0x6f/0x7c
kernel: [<ffffffff814a6e8f>] ? schedule_timeout+0x2f/0xd8
kernel: [<ffffffff81076f94>] ? timekeeping_get_ns+0xa/0x2e
kernel: [<ffffffff81077603>] ? ktime_get+0x36/0x44
kernel: [<ffffffff814a4f6c>] ? io_schedule_timeout+0x94/0xf2
kernel: [<ffffffff814a4f6c>] ? io_schedule_timeout+0x94/0xf2
kernel: [<ffffffff814a590b>] ? bit_wait_io+0x2c/0x30
kernel: [<ffffffff814a5694>] ? __wait_on_bit+0x41/0x73
kernel: [<ffffffff8109eba8>] ? wait_on_page_bit+0x6d/0x72
kernel: [<ffffffff8105d718>] ? autoremove_wake_function+0x2a/0x2a
kernel: [<ffffffff811a02d7>] ? read_extent_buffer_pages+0x1bd/0x203
kernel: [<ffffffff8117d9e9>] ? free_root_pointers+0x4c/0x4c
kernel: [<ffffffff8117e831>] ? btree_read_extent_buffer_pages.constprop.57+0x5a/0xe9
kernel: [<ffffffff8117f4f3>] ? read_tree_block+0x2d/0x45
kernel: [<ffffffff8116782a>] ? read_block_for_search.isra.34+0x22a/0x26b
kernel: [<ffffffff811656c3>] ? btrfs_set_path_blocking+0x1e/0x4a
kernel: [<ffffffff8116919b>] ? btrfs_search_slot+0x648/0x736
kernel: [<ffffffff81170559>] ? btrfs_lookup_extent_info+0xb7/0x2c7
kernel: [<ffffffff81170ee5>] ? walk_down_proc+0x9c/0x1ae
kernel: [<ffffffff81171c9d>] ? walk_down_tree+0x40/0xa4
kernel: [<ffffffff8117375f>] ? btrfs_drop_snapshot+0x2da/0x664
kernel: [<ffffffff8104ff21>] ? finish_task_switch+0x126/0x167
kernel: [<ffffffff811850f8>] ? btrfs_clean_one_deleted_snapshot+0xa6/0xb0
kernel: [<ffffffff8117eaba>] ? cleaner_kthread+0x13e/0x17b
kernel: [<ffffffff8117e97c>] ? btrfs_item_end+0x33/0x33
kernel: [<ffffffff8104d256>] ? kthread+0x95/0x9d
kernel: [<ffffffff8104d1c1>] ? kthread_parkme+0x16/0x16
kernel: [<ffffffff814a7b5f>] ? ret_from_fork+0x3f/0x70
kernel: [<ffffffff8104d1c1>] ? 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 <ziegler@uni-freiburg.de>
CC: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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;
 


Patches currently in stable-queue which might be from dsterba@suse.com are

queue-4.4/btrfs-handle-invalid-num_stripes-in-sys_array.patch
queue-4.4/btrfs-properly-set-the-termination-value-of-ctx-pos-in-readdir.patch
queue-4.4/revert-btrfs-clear-pf_nofreeze-in-cleaner_kthread.patch

                 reply	other threads:[~2016-02-24  3:54 UTC|newest]

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