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Patch "dm: set DMF_SUSPENDED* _before_ clearing DMF_NOFLUSH_SUSPENDING" has been added to the 4.7-stable tree

PATCH [email protected] 1 participant 1 message Aug 18, 2016

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

dm: set DMF_SUSPENDED* _before_ clearing DMF_NOFLUSH_SUSPENDING

to the 4.7-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:
dm-set-dmf_suspended-_before_-clearing-dmf_noflush_suspending.patch
and it can be found in the queue-4.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From eaf9a7361f47727b166688a9f2096854eef60fbe Mon Sep 17 00:00:00 2001

From: Mike Snitzer <[email protected]>
Date: Tue, 2 Aug 2016 13:07:20 -0400
Subject: dm: set DMF_SUSPENDED* _before_ clearing DMF_NOFLUSH_SUSPENDING

From: Mike Snitzer <[email protected]>

commit eaf9a7361f47727b166688a9f2096854eef60fbe upstream.

Otherwise, there is potential for both DMF_SUSPENDED* and DMF_NOFLUSH_SUSPENDING to not be set during dm_suspend() -- which is definitely _not_ a valid state.

This fix, in conjuction with "dm rq: fix the starting and stopping of blk-mq queues", addresses the potential for request-based DM multipath's __multipath_map() to see !dm_noflush_suspending() during suspend.

Reported-by Bart Van Assche <[email protected]>
Signed-off-by Mike Snitzer <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 drivers/md/dm.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)
drivers/md/dm.c +7 -7
@@ -3128,7 +3128,8 @@ static void unlock_fs(struct mapped_devi
  * Caller must hold md->suspend_lock
  */
 static int __dm_suspend(struct mapped_device *md, struct dm_table *map,
-			unsigned suspend_flags, int interruptible)
+			unsigned suspend_flags, int interruptible,
+			int dmf_suspended_flag)
 {
 	bool do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG;
 	bool noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG;

@@ -3195,6 +3196,8 @@ static int __dm_suspend(struct mapped_de
 	 * to finish.
 	 */
 	r = dm_wait_for_completion(md, interruptible);
+	if (!r)
+		set_bit(dmf_suspended_flag, &md->flags);
 
 	if (noflush)
 		clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);

@@ -3256,12 +3259,10 @@ retry:
 
 	map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
 
-	r = __dm_suspend(md, map, suspend_flags, TASK_INTERRUPTIBLE);
+	r = __dm_suspend(md, map, suspend_flags, TASK_INTERRUPTIBLE, DMF_SUSPENDED);
 	if (r)
 		goto out_unlock;
 
-	set_bit(DMF_SUSPENDED, &md->flags);
-
 	dm_table_postsuspend_targets(map);
 
 out_unlock:

@@ -3355,9 +3356,8 @@ static void __dm_internal_suspend(struct
 	 * would require changing .presuspend to return an error -- avoid this
 	 * until there is a need for more elaborate variants of internal suspend.
 	 */
-	(void) __dm_suspend(md, map, suspend_flags, TASK_UNINTERRUPTIBLE);
-
-	set_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
+	(void) __dm_suspend(md, map, suspend_flags, TASK_UNINTERRUPTIBLE,
+			    DMF_SUSPENDED_INTERNALLY);
 
 	dm_table_postsuspend_targets(map);
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.7/dm-set-dmf_suspended-_before_-clearing-dmf_noflush_suspending.patch queue-4.7/dm-verity-fec-fix-block-calculation.patch queue-4.7/dm-fix-second-blk_delay_queue-parameter-to-be-in-msec-units-not-jiffies.patch