Commit 5df96f2b authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
Browse files

dm integrity: fix integrity recalculation that is improperly skipped 



Commit adc0daad ("dm: report suspended
device during destroy") broke integrity recalculation.

The problem is dm_suspended() returns true not only during suspend,
but also during resume. So this race condition could occur:
1. dm_integrity_resume calls queue_work(ic->recalc_wq, &ic->recalc_work)
2. integrity_recalc (&ic->recalc_work) preempts the current thread
3. integrity_recalc calls if (unlikely(dm_suspended(ic->ti))) goto unlock_ret;
4. integrity_recalc exits and no recalculating is done.

To fix this race condition, add a function dm_post_suspending that is
only true during the postsuspend phase and use it instead of
dm_suspended().

Signed-off-by: Mikulas Patocka <mpatocka redhat com>
Fixes: adc0daad ("dm: report suspended device during destroy")
Cc: stable vger kernel org # v4.18+
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 6958c1c6

drivers/md/dm-integrity.c

+2 −2
Original line number Diff line number Diff line
@@ -2420,7 +2420,7 @@ static void integrity_writer(struct work_struct *w) 
	unsigned prev_free_sectors;



	/* the following test is not needed, but it tests the replay code */

	if (unlikely(dm_suspended(ic->ti)) && !ic->meta_dev)

	if (unlikely(dm_post_suspending(ic->ti)) && !ic->meta_dev)

		return;



	spin_lock_irq(&ic->endio_wait.lock);
@@ -2481,7 +2481,7 @@ static void integrity_recalc(struct work_struct *w) 


next_chunk:



	if (unlikely(dm_suspended(ic->ti)))

	if (unlikely(dm_post_suspending(ic->ti)))

		goto unlock_ret;



	range.logical_sector = le64_to_cpu(ic->sb->recalc_sector);

drivers/md/dm.c

+17 −0
Original line number Diff line number Diff line
@@ -143,6 +143,7 @@ EXPORT_SYMBOL_GPL(dm_bio_get_target_bio_nr); 
#define DMF_NOFLUSH_SUSPENDING 5

#define DMF_DEFERRED_REMOVE 6

#define DMF_SUSPENDED_INTERNALLY 7

#define DMF_POST_SUSPENDING 8



#define DM_NUMA_NODE NUMA_NO_NODE

static int dm_numa_node = DM_NUMA_NODE;
@@ -2408,6 +2409,7 @@ static void __dm_destroy(struct mapped_device *md, bool wait) 
	if (!dm_suspended_md(md)) {

		dm_table_presuspend_targets(map);

		set_bit(DMF_SUSPENDED, &md->flags);

		set_bit(DMF_POST_SUSPENDING, &md->flags);

		dm_table_postsuspend_targets(map);

	}

	/* dm_put_live_table must be before msleep, otherwise deadlock is possible */
@@ -2766,7 +2768,9 @@ retry: 
	if (r)

		goto out_unlock;



	set_bit(DMF_POST_SUSPENDING, &md->flags);

	dm_table_postsuspend_targets(map);

	clear_bit(DMF_POST_SUSPENDING, &md->flags);



out_unlock:

	mutex_unlock(&md->suspend_lock);
@@ -2863,7 +2867,9 @@ static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_fla 
	(void) __dm_suspend(md, map, suspend_flags, TASK_UNINTERRUPTIBLE,

			    DMF_SUSPENDED_INTERNALLY);



	set_bit(DMF_POST_SUSPENDING, &md->flags);

	dm_table_postsuspend_targets(map);

	clear_bit(DMF_POST_SUSPENDING, &md->flags);

}



static void __dm_internal_resume(struct mapped_device *md)
@@ -3024,6 +3030,11 @@ int dm_suspended_md(struct mapped_device *md) 
	return test_bit(DMF_SUSPENDED, &md->flags);

}



static int dm_post_suspending_md(struct mapped_device *md)

{

	return test_bit(DMF_POST_SUSPENDING, &md->flags);

}



int dm_suspended_internally_md(struct mapped_device *md)

{

	return test_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
@@ -3040,6 +3051,12 @@ int dm_suspended(struct dm_target *ti) 
}

EXPORT_SYMBOL_GPL(dm_suspended);



int dm_post_suspending(struct dm_target *ti)

{

	return dm_post_suspending_md(dm_table_get_md(ti->table));

}

EXPORT_SYMBOL_GPL(dm_post_suspending);



int dm_noflush_suspending(struct dm_target *ti)

{

	return __noflush_suspending(dm_table_get_md(ti->table));

include/linux/device-mapper.h

+1 −0
Original line number Diff line number Diff line
@@ -426,6 +426,7 @@ const char *dm_device_name(struct mapped_device *md); 
int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);

struct gendisk *dm_disk(struct mapped_device *md);

int dm_suspended(struct dm_target *ti);

int dm_post_suspending(struct dm_target *ti);

int dm_noflush_suspending(struct dm_target *ti);

void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors);

union map_info *dm_get_rq_mapinfo(struct request *rq);

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