diff options
Diffstat (limited to 'drivers/md/dm-snap.c')
| -rw-r--r-- | drivers/md/dm-snap.c | 32 |
1 files changed, 24 insertions, 8 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index b2d9d1ac28ad..6c96db26b87c 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -229,19 +229,21 @@ static void __insert_origin(struct origin *o) */ static int register_snapshot(struct dm_snapshot *snap) { - struct origin *o; + struct origin *o, *new_o; struct block_device *bdev = snap->origin->bdev; + new_o = kmalloc(sizeof(*new_o), GFP_KERNEL); + if (!new_o) + return -ENOMEM; + down_write(&_origins_lock); o = __lookup_origin(bdev); - if (!o) { + if (o) + kfree(new_o); + else { /* New origin */ - o = kmalloc(sizeof(*o), GFP_KERNEL); - if (!o) { - up_write(&_origins_lock); - return -ENOMEM; - } + o = new_o; /* Initialise the struct */ INIT_LIST_HEAD(&o->snapshots); @@ -368,6 +370,7 @@ static struct dm_snap_pending_exception *alloc_pending_exception(struct dm_snaps struct dm_snap_pending_exception *pe = mempool_alloc(s->pending_pool, GFP_NOIO); + atomic_inc(&s->pending_exceptions_count); pe->snap = s; return pe; @@ -375,7 +378,11 @@ static struct dm_snap_pending_exception *alloc_pending_exception(struct dm_snaps static void free_pending_exception(struct dm_snap_pending_exception *pe) { - mempool_free(pe, pe->snap->pending_pool); + struct dm_snapshot *s = pe->snap; + + mempool_free(pe, s->pending_pool); + smp_mb__before_atomic_dec(); + atomic_dec(&s->pending_exceptions_count); } static void insert_completed_exception(struct dm_snapshot *s, @@ -600,6 +607,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) s->valid = 1; s->active = 0; + atomic_set(&s->pending_exceptions_count, 0); init_rwsem(&s->lock); spin_lock_init(&s->pe_lock); s->ti = ti; @@ -726,6 +734,14 @@ static void snapshot_dtr(struct dm_target *ti) /* After this returns there can be no new kcopyd jobs. */ unregister_snapshot(s); + while (atomic_read(&s->pending_exceptions_count)) + yield(); + /* + * Ensure instructions in mempool_destroy aren't reordered + * before atomic_read. + */ + smp_mb(); + #ifdef CONFIG_DM_DEBUG for (i = 0; i < DM_TRACKED_CHUNK_HASH_SIZE; i++) BUG_ON(!hlist_empty(&s->tracked_chunk_hash[i])); |