dm snapshot: cope with chunk size larger than origin

[pandora-kernel.git] / drivers / md / dm-snap.c

diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 57f1bf7..8a4a9c8 100644 (file)
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -296,6 +296,7 @@ static void __insert_origin(struct origin *o)
  */
 static int register_snapshot(struct dm_snapshot *snap)
 {
+       struct dm_snapshot *l;
        struct origin *o, *new_o;
        struct block_device *bdev = snap->origin->bdev;
 
@@ -319,7 +320,11 @@ static int register_snapshot(struct dm_snapshot *snap)
                __insert_origin(o);
        }
 
-       list_add_tail(&snap->list, &o->snapshots);
+       /* Sort the list according to chunk size, largest-first smallest-last */
+       list_for_each_entry(l, &o->snapshots, list)
+               if (l->store->chunk_size < snap->store->chunk_size)
+                       break;
+       list_add_tail(&snap->list, &l->list);
 
        up_write(&_origins_lock);
        return 0;
@@ -548,6 +553,8 @@ static int init_hash_tables(struct dm_snapshot *s)
        hash_size = min(origin_dev_size, cow_dev_size) >> s->store->chunk_shift;
        hash_size = min(hash_size, max_buckets);
 
+       if (hash_size < 64)
+               hash_size = 64;
        hash_size = rounddown_pow_of_two(hash_size);
        if (init_exception_table(&s->complete, hash_size,
                                 DM_CHUNK_CONSECUTIVE_BITS))
@@ -668,6 +675,11 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
        bio_list_init(&s->queued_bios);
        INIT_WORK(&s->queued_bios_work, flush_queued_bios);
 
+       if (!s->store->chunk_size) {
+               ti->error = "Chunk size not set";
+               goto bad_load_and_register;
+       }
+
        /* Add snapshot to the list of snapshots for this origin */
        /* Exceptions aren't triggered till snapshot_resume() is called */
        if (register_snapshot(s)) {
@@ -951,7 +963,7 @@ static void start_copy(struct dm_snap_pending_exception *pe)
 
        src.bdev = bdev;
        src.sector = chunk_to_sector(s->store, pe->e.old_chunk);
-       src.count = min(s->store->chunk_size, dev_size - src.sector);
+       src.count = min((sector_t)s->store->chunk_size, dev_size - src.sector);
 
        dest.bdev = s->store->cow->bdev;
        dest.sector = chunk_to_sector(s->store, pe->e.new_chunk);
@@ -1144,6 +1156,9 @@ static int snapshot_status(struct dm_target *ti, status_type_t type,
 
        switch (type) {
        case STATUSTYPE_INFO:
+
+               down_write(&snap->lock);
+
                if (!snap->valid)
                        DMEMIT("Invalid");
                else {
@@ -1159,6 +1174,9 @@ static int snapshot_status(struct dm_target *ti, status_type_t type,
                        else
                                DMEMIT("Unknown");
                }
+
+               up_write(&snap->lock);
+
                break;
 
        case STATUSTYPE_TABLE:
@@ -1388,7 +1406,7 @@ static void origin_resume(struct dm_target *ti)
        struct dm_dev *dev = ti->private;
        struct dm_snapshot *snap;
        struct origin *o;
-       chunk_t chunk_size = 0;
+       unsigned chunk_size = 0;
 
        down_read(&_origins_lock);
        o = __lookup_origin(dev->bdev);
@@ -1465,7 +1483,7 @@ static int __init dm_snapshot_init(void)
        r = dm_register_target(&snapshot_target);
        if (r) {
                DMERR("snapshot target register failed %d", r);
-               return r;
+               goto bad_register_snapshot_target;
        }
 
        r = dm_register_target(&origin_target);
@@ -1522,6 +1540,9 @@ bad2:
        dm_unregister_target(&origin_target);
 bad1:
        dm_unregister_target(&snapshot_target);
+
+bad_register_snapshot_target:
+       dm_exception_store_exit();
        return r;
 }