Patch "btrfs: cleaner_kthread() doesn't need explicit freeze" has been added to the 4.5-stable tree

Patch "btrfs: cleaner_kthread() doesn't need explicit freeze" has been added to the 4.5-stable tree

[gregkh]

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

    btrfs: cleaner_kthread() doesn't need explicit freeze

to the 4.5-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:
     btrfs-cleaner_kthread-doesn-t-need-explicit-freeze.patch
and it can be found in the queue-4.5 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 838fe1887765f4cc679febea60d87d2a06bd300e Mon Sep 17 00:00:00 2001
From: Jiri Kosina <jkosina@suse.cz>
Date: Tue, 15 Mar 2016 11:28:54 +0100
Subject: btrfs: cleaner_kthread() doesn't need explicit freeze

From: Jiri Kosina <jkosina@suse.cz>

commit 838fe1887765f4cc679febea60d87d2a06bd300e upstream.

cleaner_kthread() is not marked freezable, and therefore calling
try_to_freeze() in its context is a pointless no-op.

In addition to that, as has been clearly demonstrated by 80ad623edd2d
("Revert "btrfs: clear PF_NOFREEZE in cleaner_kthread()"), it's perfectly
valid / legal for cleaner_kthread() to stay scheduled out in an arbitrary
place during suspend (in that particular example that was waiting for
reading of extent pages), so there is no need to leave any traces of
freezer in this kthread.

Fixes: 80ad623edd2d ("Revert "btrfs: clear PF_NOFREEZE in cleaner_kthread()")
Fixes: 696249132158 ("btrfs: clear PF_NOFREEZE in cleaner_kthread()")
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/btrfs/disk-io.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1830,7 +1830,7 @@ static int cleaner_kthread(void *arg)
 		 */
 		btrfs_delete_unused_bgs(root->fs_info);
 sleep:
-		if (!try_to_freeze() && !again) {
+		if (!again) {
 			set_current_state(TASK_INTERRUPTIBLE);
 			if (!kthread_should_stop())
 				schedule();


Patches currently in stable-queue which might be from jkosina@suse.cz are

queue-4.5/btrfs-cleaner_kthread-doesn-t-need-explicit-freeze.patch