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dm integrity: fix integrity recalculation that is improperly skipped

Browse Source 
Commit adc0daad36 ("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: adc0daad36 ("dm: report suspended device during destroy")
Cc: stable vger kernel org # v4.18+
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mikulas Patocka 2020-07-23 10:42:09 -04:00 committed by Mike Snitzer
parent 6958c1c640
commit 5df96f2b9f
3 changed files with 20 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/md/dm-integrity.c
View File

@ -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);

17
drivers/md/dm.c
View File

@ -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));

1
include/linux/device-mapper.h
View File

@ -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);