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dm thin: do not allow thin device activation while pool is suspended

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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>
This commit is contained in:
Mike Snitzer 2014-11-07 15:09:46 -05:00
parent d67ee213fa
commit 80e96c5484
1 changed files with 45 additions and 10 deletions
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55
drivers/md/dm-thin.c
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@ -224,6 +224,7 @@ struct pool {
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 @@ static struct pool *pool_create(struct mapped_device *pool_md,
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 @@ static void pool_resume(struct dm_target *ti)
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 @@ static struct target_type pool_target = {
.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 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
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 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
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 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
*/
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);