Commit 85ad1d13 authored by Guoqing Jiang's avatar Guoqing Jiang Committed by Shaohua Li
Browse files

md: set MD_CHANGE_PENDING in a atomic region 



Some code waits for a metadata update by:

1. flagging that it is needed (MD_CHANGE_DEVS or MD_CHANGE_CLEAN)
2. setting MD_CHANGE_PENDING and waking the management thread
3. waiting for MD_CHANGE_PENDING to be cleared

If the first two are done without locking, the code in md_update_sb()
which checks if it needs to repeat might test if an update is needed
before step 1, then clear MD_CHANGE_PENDING after step 2, resulting
in the wait returning early.

So make sure all places that set MD_CHANGE_PENDING are atomicial, and
bit_clear_unless (suggested by Neil) is introduced for the purpose.

Cc: Martin Kepplinger <martink@posteo.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: <linux-kernel@vger.kernel.org>
Reviewed-by: default avatarNeilBrown <neilb@suse.com>
Signed-off-by: default avatarGuoqing Jiang <gqjiang@suse.com>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent fe67d19a

drivers/md/md.c

+14 −13
Original line number Diff line number Diff line
@@ -2295,12 +2295,16 @@ repeat: 
	if (mddev_is_clustered(mddev)) {

		if (test_and_clear_bit(MD_CHANGE_DEVS, &mddev->flags))

			force_change = 1;

		if (test_and_clear_bit(MD_CHANGE_CLEAN, &mddev->flags))

			nospares = 1;

		ret = md_cluster_ops->metadata_update_start(mddev);

		/* Has someone else has updated the sb */

		if (!does_sb_need_changing(mddev)) {

			if (ret == 0)

				md_cluster_ops->metadata_update_cancel(mddev);

			clear_bit(MD_CHANGE_PENDING, &mddev->flags);

			bit_clear_unless(&mddev->flags, BIT(MD_CHANGE_PENDING),

							 BIT(MD_CHANGE_DEVS) |

							 BIT(MD_CHANGE_CLEAN));

			return;

		}

	}
@@ -2434,15 +2438,11 @@ repeat: 
	if (mddev_is_clustered(mddev) && ret == 0)

		md_cluster_ops->metadata_update_finish(mddev);



	spin_lock(&mddev->lock);

	if (mddev->in_sync != sync_req ||

	    test_bit(MD_CHANGE_DEVS, &mddev->flags)) {

	    !bit_clear_unless(&mddev->flags, BIT(MD_CHANGE_PENDING),

			       BIT(MD_CHANGE_DEVS) | BIT(MD_CHANGE_CLEAN)))

		/* have to write it out again */

		spin_unlock(&mddev->lock);

		goto repeat;

	}

	clear_bit(MD_CHANGE_PENDING, &mddev->flags);

	spin_unlock(&mddev->lock);

	wake_up(&mddev->sb_wait);

	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))

		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
@@ -8147,18 +8147,18 @@ void md_do_sync(struct md_thread *thread) 
		}

	}

 skip:

	set_bit(MD_CHANGE_DEVS, &mddev->flags);



	if (mddev_is_clustered(mddev) &&

	    ret == 0) {

		/* set CHANGE_PENDING here since maybe another

		 * update is needed, so other nodes are informed */

		set_bit(MD_CHANGE_PENDING, &mddev->flags);

		set_mask_bits(&mddev->flags, 0,

			      BIT(MD_CHANGE_PENDING) | BIT(MD_CHANGE_DEVS));

		md_wakeup_thread(mddev->thread);

		wait_event(mddev->sb_wait,

			   !test_bit(MD_CHANGE_PENDING, &mddev->flags));

		md_cluster_ops->resync_finish(mddev);

	}

	} else

		set_bit(MD_CHANGE_DEVS, &mddev->flags);



	spin_lock(&mddev->lock);

	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
@@ -8550,6 +8550,7 @@ EXPORT_SYMBOL(md_finish_reshape); 
int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,

		       int is_new)

{

	struct mddev *mddev = rdev->mddev;

	int rv;

	if (is_new)

		s += rdev->new_data_offset;
@@ -8559,8 +8560,8 @@ int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors, 
	if (rv == 0) {

		/* Make sure they get written out promptly */

		sysfs_notify_dirent_safe(rdev->sysfs_state);

		set_bit(MD_CHANGE_CLEAN, &rdev->mddev->flags);

		set_bit(MD_CHANGE_PENDING, &rdev->mddev->flags);

		set_mask_bits(&mddev->flags, 0,

			      BIT(MD_CHANGE_CLEAN) | BIT(MD_CHANGE_PENDING));

		md_wakeup_thread(rdev->mddev->thread);

		return 1;

	} else

drivers/md/raid1.c

+2 −2
Original line number Diff line number Diff line
@@ -1474,8 +1474,8 @@ static void raid1_error(struct mddev *mddev, struct md_rdev *rdev) 
	 * if recovery is running, make sure it aborts.

	 */

	set_bit(MD_RECOVERY_INTR, &mddev->recovery);

	set_bit(MD_CHANGE_DEVS, &mddev->flags);

	set_bit(MD_CHANGE_PENDING, &mddev->flags);

	set_mask_bits(&mddev->flags, 0,

		      BIT(MD_CHANGE_DEVS) | BIT(MD_CHANGE_PENDING));

	printk(KERN_ALERT

	       "md/raid1:%s: Disk failure on %s, disabling device.\n"

	       "md/raid1:%s: Operation continuing on %d devices.\n",

drivers/md/raid10.c

+4 −4
Original line number Diff line number Diff line
@@ -1102,8 +1102,8 @@ static void __make_request(struct mddev *mddev, struct bio *bio) 
		bio->bi_iter.bi_sector < conf->reshape_progress))) {

		/* Need to update reshape_position in metadata */

		mddev->reshape_position = conf->reshape_progress;

		set_bit(MD_CHANGE_DEVS, &mddev->flags);

		set_bit(MD_CHANGE_PENDING, &mddev->flags);

		set_mask_bits(&mddev->flags, 0,

			      BIT(MD_CHANGE_DEVS) | BIT(MD_CHANGE_PENDING));

		md_wakeup_thread(mddev->thread);

		wait_event(mddev->sb_wait,

			   !test_bit(MD_CHANGE_PENDING, &mddev->flags));
@@ -1591,8 +1591,8 @@ static void raid10_error(struct mddev *mddev, struct md_rdev *rdev) 
	set_bit(MD_RECOVERY_INTR, &mddev->recovery);

	set_bit(Blocked, &rdev->flags);

	set_bit(Faulty, &rdev->flags);

	set_bit(MD_CHANGE_DEVS, &mddev->flags);

	set_bit(MD_CHANGE_PENDING, &mddev->flags);

	set_mask_bits(&mddev->flags, 0,

		      BIT(MD_CHANGE_DEVS) | BIT(MD_CHANGE_PENDING));

	spin_unlock_irqrestore(&conf->device_lock, flags);

	printk(KERN_ALERT

	       "md/raid10:%s: Disk failure on %s, disabling device.\n"

drivers/md/raid5-cache.c

+2 −2
Original line number Diff line number Diff line
@@ -712,8 +712,8 @@ static void r5l_write_super_and_discard_space(struct r5l_log *log, 
	 * in_teardown check workaround this issue.

	 */

	if (!log->in_teardown) {

		set_bit(MD_CHANGE_DEVS, &mddev->flags);

		set_bit(MD_CHANGE_PENDING, &mddev->flags);

		set_mask_bits(&mddev->flags, 0,

			      BIT(MD_CHANGE_DEVS) | BIT(MD_CHANGE_PENDING));

		md_wakeup_thread(mddev->thread);

		wait_event(mddev->sb_wait,

			!test_bit(MD_CHANGE_PENDING, &mddev->flags) ||

drivers/md/raid5.c

+2 −2
Original line number Diff line number Diff line
@@ -2514,8 +2514,8 @@ static void raid5_error(struct mddev *mddev, struct md_rdev *rdev) 


	set_bit(Blocked, &rdev->flags);

	set_bit(Faulty, &rdev->flags);

	set_bit(MD_CHANGE_DEVS, &mddev->flags);

	set_bit(MD_CHANGE_PENDING, &mddev->flags);

	set_mask_bits(&mddev->flags, 0,

		      BIT(MD_CHANGE_DEVS) | BIT(MD_CHANGE_PENDING));

	printk(KERN_ALERT

	       "md/raid:%s: Disk failure on %s, disabling device.\n"

	       "md/raid:%s: Operation continuing on %d devices.\n",

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