[dm-devel] [PATCH 9/9] dm snapshot: add shared_snapshot_target
FUJITA Tomonori
fujita.tomonori at lab.ntt.co.jp
Mon Oct 27 12:07:56 UTC 2008
Signed-off-by: FUJITA Tomonori <fujita.tomonori at lab.ntt.co.jp>
---
drivers/md/dm-snap.c | 199 +++++++++++++++++++++++++++++++++++++++++++++-----
1 files changed, 181 insertions(+), 18 deletions(-)
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 1b9c1ef..bbdfff3 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -1140,11 +1140,9 @@ static void snapshot_resume(struct dm_target *ti)
up_write(&s->lock);
}
-static int snapshot_status(struct dm_target *ti, status_type_t type,
- char *result, unsigned int maxlen)
+static int do_snapshot_status(struct dm_snapshot *snap, status_type_t type,
+ char *result, unsigned int maxlen, u64 snapid)
{
- struct dm_snapshot *snap = ti->private;
-
switch (type) {
case STATUSTYPE_INFO:
if (!snap->valid)
@@ -1170,16 +1168,31 @@ static int snapshot_status(struct dm_target *ti, status_type_t type,
* to make private copies if the output is to
* make sense.
*/
- snprintf(result, maxlen, "%s %s %c %llu",
- snap->origin->name, snap->cow->name,
- snap->type,
- (unsigned long long)snap->chunk_size);
+ if (snap->type == 'S')
+ snprintf(result, maxlen, "%s %s %c %llu %llu",
+ snap->origin->name, snap->cow->name,
+ snap->type,
+ (unsigned long long)snap->chunk_size,
+ snapid);
+ else
+ snprintf(result, maxlen, "%s %s %c %llu",
+ snap->origin->name, snap->cow->name,
+ snap->type,
+ (unsigned long long)snap->chunk_size);
break;
}
return 0;
}
+static int snapshot_status(struct dm_target *ti, status_type_t type,
+ char *result, unsigned int maxlen)
+{
+ struct dm_snapshot *snap = ti->private;
+
+ return do_snapshot_status(snap, type, result, maxlen, 0);
+}
+
/*-----------------------------------------------------------------
* Origin methods
*---------------------------------------------------------------*/
@@ -1393,7 +1406,6 @@ static int origin_status(struct dm_target *ti, status_type_t type, char *result,
/*
* shared exception origin code
*/
-
struct dm_shared_origin {
struct dm_dev *origin;
@@ -1520,6 +1532,134 @@ static int shared_origin_message(struct dm_target *ti, unsigned argc,
return snap->store.message(&snap->store, argc, argv);
}
+/*
+ * shared exception snapshot code
+ */
+
+struct dm_shared_snapshot {
+ struct dm_dev *origin;
+
+ struct dm_snapshot *snap;
+ u64 snapid;
+};
+
+/*
+ * Construct a shared origin mapping: <origin_dev> <snapshot id>
+ */
+static int shared_snapshot_ctr(struct dm_target *ti, unsigned int argc,
+ char **argv)
+{
+ int r;
+ struct dm_shared_origin *dso;
+ struct dm_shared_snapshot *dss;
+ struct dm_snapshot *origin_snap;
+ struct dm_dev *dev;
+ struct origin *o;
+ u64 id;
+
+ if (argc != 2) {
+ ti->error = "snapshot: incorrect number of arguments";
+ return -EINVAL;
+ }
+
+ dss = kzalloc(sizeof(*dss), GFP_KERNEL);
+ if (!dss)
+ return -ENOMEM;
+
+ id = simple_strtoul(argv[1], NULL, 10);
+ if (id >= 64) {
+ r = -EINVAL;
+ ti->error = "Invalid snapid";
+ goto out;
+ }
+
+ r = dm_get_device(ti, argv[0], 0, ti->len, FMODE_READ, &dev);
+ if (r) {
+ ti->error = "Cannot get origin device";
+ goto out;
+ }
+
+ r = -EINVAL;
+ down_read(&_origins_lock);
+ o = __lookup_origin(dev->bdev);
+ if (o && !list_empty(&o->snapshots)) {
+ int nr;
+ unsigned long map[DIV_ROUND_UP(MAX_SNAPSHOTS, BITS_PER_LONG)];
+ struct exception_store *store;
+
+ memset(map, 0, sizeof(map));
+
+ origin_snap = list_first_entry(&o->snapshots,
+ struct dm_snapshot, list);
+ store = &origin_snap->store;
+ dso = origin_snap->ti->private;
+
+ down_write(&store->snap->lock);
+ nr = store->get_snapshot_info(store, map, sizeof(map));
+ up_write(&store->snap->lock);
+
+ if (test_bit(id, map)) {
+ dm_table_get(origin_snap->ti->table);
+ ti->private = dss;
+ dss->snap = origin_snap;
+ dss->snapid = id;
+ dss->origin = dev;
+
+ ti->split_io = origin_snap->chunk_size;
+ r = 0;
+
+ printk("%s %d: %lld\n", __FUNCTION__, __LINE__,
+ (unsigned long long)id);
+
+ } else {
+ ti->error = "non-exist snapshot";
+ r = -EINVAL;
+ }
+ }
+ up_read(&_origins_lock);
+
+ if (r)
+ dm_put_device(ti, dev);
+out:
+ if (r)
+ kfree(dss);
+
+ return r;
+}
+
+static void shared_snapshot_dtr(struct dm_target *ti)
+{
+ struct dm_shared_snapshot *dss = ti->private;
+
+ dm_table_put(dss->snap->ti->table);
+ dm_put_device(ti, dss->origin);
+ kfree(dss);
+}
+
+static int shared_snapshot_map(struct dm_target *ti, struct bio *bio,
+ union map_info *map_context)
+{
+ struct dm_shared_snapshot *dss = ti->private;
+
+ return do_snapshot_map(dss->snap, bio, map_context, dss->snapid);
+}
+
+static int shared_snapshot_end_io(struct dm_target *ti, struct bio *bio,
+ int error, union map_info *map_context)
+{
+ struct dm_shared_snapshot *dss = ti->private;
+
+ return do_snapshot_end_io(dss->snap, bio, error, map_context);
+}
+
+static int shared_snapshot_status(struct dm_target *ti, status_type_t type,
+ char *result, unsigned int maxlen)
+{
+ struct dm_shared_snapshot *dss = ti->private;
+
+ return do_snapshot_status(dss->snap, type, result, maxlen, dss->snapid);
+}
+
static struct target_type origin_target = {
.name = "snapshot-origin",
.version = {1, 6, 0},
@@ -1554,6 +1694,17 @@ static struct target_type shared_origin_target = {
.message = shared_origin_message,
};
+static struct target_type shared_snapshot_target = {
+ .name = "s-snap",
+ .version = {1, 0, 0},
+ .module = THIS_MODULE,
+ .ctr = shared_snapshot_ctr,
+ .dtr = shared_snapshot_dtr,
+ .map = shared_snapshot_map,
+ .end_io = shared_snapshot_end_io,
+ .status = shared_snapshot_status,
+};
+
static int __init dm_snapshot_init(void)
{
int r;
@@ -1570,37 +1721,43 @@ static int __init dm_snapshot_init(void)
goto bad1;
}
+ r = dm_register_target(&shared_snapshot_target);
+ if (r) {
+ DMERR("shared snapshot target register failed %d", r);
+ goto bad2;
+ }
+
r = dm_register_target(&shared_origin_target);
if (r) {
DMERR("shared origin target register failed %d", r);
- goto bad2;
+ goto bad3;
}
r = init_origin_hash();
if (r) {
DMERR("init_origin_hash failed.");
- goto bad3;
+ goto bad4;
}
exception_cache = KMEM_CACHE(dm_snap_exception, 0);
if (!exception_cache) {
DMERR("Couldn't create exception cache.");
r = -ENOMEM;
- goto bad4;
+ goto bad5;
}
pending_cache = KMEM_CACHE(dm_snap_pending_exception, 0);
if (!pending_cache) {
DMERR("Couldn't create pending cache.");
r = -ENOMEM;
- goto bad5;
+ goto bad6;
}
tracked_chunk_cache = KMEM_CACHE(dm_snap_tracked_chunk, 0);
if (!tracked_chunk_cache) {
DMERR("Couldn't create cache to track chunks in use.");
r = -ENOMEM;
- goto bad6;
+ goto bad7;
}
ksnapd = create_singlethread_workqueue("ksnapd");
@@ -1614,14 +1771,16 @@ static int __init dm_snapshot_init(void)
bad_pending_pool:
kmem_cache_destroy(tracked_chunk_cache);
- bad6:
+ bad7:
kmem_cache_destroy(pending_cache);
- bad5:
+ bad6:
kmem_cache_destroy(exception_cache);
- bad4:
+ bad5:
exit_origin_hash();
- bad3:
+ bad4:
dm_unregister_target(&shared_origin_target);
+ bad3:
+ dm_unregister_target(&shared_snapshot_target);
bad2:
dm_unregister_target(&origin_target);
bad1:
@@ -1643,6 +1802,10 @@ static void __exit dm_snapshot_exit(void)
if (r)
DMERR("origin unregister failed %d", r);
+ r = dm_unregister_target(&shared_snapshot_target);
+ if (r)
+ DMERR("shared snapshot unregister failed %d", r);
+
r = dm_unregister_target(&shared_origin_target);
if (r)
DMERR("shared origin unregister failed %d", r);
--
1.5.5.GIT
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