dm thin: do not allow thin device activation while pool is suspended
Otherwise IO could be issued to the pool while it is suspended.
Care was taken to properly interlock between the thin and thin-pool
targets when accessing the pool's 'suspended' flag. The thin_ctr will
not add a new thin device to the pool's active_thins list if the pool is
susepended.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 64fd4de..f1b53e3 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -224,6 +224,7 @@
struct pool_features pf;
bool low_water_triggered:1; /* A dm event has been sent */
+ bool suspended:1;
struct dm_bio_prison *prison;
struct dm_kcopyd_client *copier;
@@ -2575,6 +2576,7 @@
INIT_LIST_HEAD(&pool->prepared_discards);
INIT_LIST_HEAD(&pool->active_thins);
pool->low_water_triggered = false;
+ pool->suspended = true;
pool->shared_read_ds = dm_deferred_set_create();
if (!pool->shared_read_ds) {
@@ -3119,12 +3121,36 @@
spin_lock_irqsave(&pool->lock, flags);
pool->low_water_triggered = false;
+ pool->suspended = false;
spin_unlock_irqrestore(&pool->lock, flags);
+
requeue_bios(pool);
do_waker(&pool->waker.work);
}
+static void pool_presuspend(struct dm_target *ti)
+{
+ struct pool_c *pt = ti->private;
+ struct pool *pool = pt->pool;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pool->lock, flags);
+ pool->suspended = true;
+ spin_unlock_irqrestore(&pool->lock, flags);
+}
+
+static void pool_presuspend_undo(struct dm_target *ti)
+{
+ struct pool_c *pt = ti->private;
+ struct pool *pool = pt->pool;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pool->lock, flags);
+ pool->suspended = false;
+ spin_unlock_irqrestore(&pool->lock, flags);
+}
+
static void pool_postsuspend(struct dm_target *ti)
{
struct pool_c *pt = ti->private;
@@ -3592,6 +3618,8 @@
.ctr = pool_ctr,
.dtr = pool_dtr,
.map = pool_map,
+ .presuspend = pool_presuspend,
+ .presuspend_undo = pool_presuspend_undo,
.postsuspend = pool_postsuspend,
.preresume = pool_preresume,
.resume = pool_resume,
@@ -3721,18 +3749,18 @@
if (get_pool_mode(tc->pool) == PM_FAIL) {
ti->error = "Couldn't open thin device, Pool is in fail mode";
r = -EINVAL;
- goto bad_thin_open;
+ goto bad_pool;
}
r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
if (r) {
ti->error = "Couldn't open thin internal device";
- goto bad_thin_open;
+ goto bad_pool;
}
r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
if (r)
- goto bad_target_max_io_len;
+ goto bad;
ti->num_flush_bios = 1;
ti->flush_supported = true;
@@ -3747,14 +3775,16 @@
ti->split_discard_bios = true;
}
- dm_put(pool_md);
-
mutex_unlock(&dm_thin_pool_table.mutex);
- atomic_set(&tc->refcount, 1);
- init_completion(&tc->can_destroy);
-
spin_lock_irqsave(&tc->pool->lock, flags);
+ if (tc->pool->suspended) {
+ spin_unlock_irqrestore(&tc->pool->lock, flags);
+ mutex_lock(&dm_thin_pool_table.mutex); /* reacquire for __pool_dec */
+ ti->error = "Unable to activate thin device while pool is suspended";
+ r = -EINVAL;
+ goto bad;
+ }
list_add_tail_rcu(&tc->list, &tc->pool->active_thins);
spin_unlock_irqrestore(&tc->pool->lock, flags);
/*
@@ -3765,11 +3795,16 @@
*/
synchronize_rcu();
+ dm_put(pool_md);
+
+ atomic_set(&tc->refcount, 1);
+ init_completion(&tc->can_destroy);
+
return 0;
-bad_target_max_io_len:
+bad:
dm_pool_close_thin_device(tc->td);
-bad_thin_open:
+bad_pool:
__pool_dec(tc->pool);
bad_pool_lookup:
dm_put(pool_md);