From 95d4ea71a3d904a054d42fd20d4d8f420946cdac Mon Sep 17 00:00:00 2001 From: FUJITA Tomonori Date: Fri, 15 Aug 2008 11:27:51 +0900 Subject: [PATCH] dm snapshot: add shared_origin_target Signed-off-by: FUJITA Tomonori --- drivers/md/dm-snap.c | 175 +++++++++++++++++++++++++++++++++++++++++++++++--- 1 files changed, 165 insertions(+), 10 deletions(-) diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index bea98b4..ae8bb34 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -575,8 +575,8 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) cow_path = argv[1]; persistent = toupper(*argv[2]); - if (persistent != 'P' && persistent != 'N') { - ti->error = "Persistent flag is not P or N"; + if (persistent != 'P' && persistent != 'N' && persistent != 'S') { + ti->error = "Persistent flag is not P, N, or S"; r = -EINVAL; goto bad1; } @@ -625,7 +625,9 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) s->store.snap = s; - if (persistent == 'P') + if (persistent == 'S') + r = dm_create_shared(&s->store); + else if (persistent == 'P') r = dm_create_persistent(&s->store); else r = dm_create_transient(&s->store); @@ -1393,6 +1395,136 @@ static int origin_status(struct dm_target *ti, status_type_t type, char *result, return 0; } +/* + * shared exception origin code + */ + +struct dm_shared_origin { + struct dm_dev *origin; + + struct dm_snapshot *origin_snap; +}; + +/* + * Construct a shared origin mapping:

+ */ +static int shared_origin_ctr(struct dm_target *ti, unsigned int argc, + char **argv) +{ + int r; + struct dm_shared_origin *dso; + struct dm_snapshot *s; + + if (argc != 4) { + ti->error = "origin: incorrect number of arguments"; + return -EINVAL; + } + + dso = kzalloc(sizeof(*dso), GFP_KERNEL); + if (!dso) + return -ENOMEM; + + r = snapshot_ctr(ti, argc, argv); + if (r) + goto out; + + s = ti->private; + + if (s->chunk_size != 16) { + r = -EINVAL; + ti->error = "invalid chunk size"; + snapshot_dtr(ti); + goto out; + } + + s->active = 1; + + dso->origin = s->origin; + dso->origin_snap = s; + ti->private = dso; + + return 0; +out: + kfree(dso); + return r; +} + +static void shared_origin_dtr(struct dm_target *ti) +{ + struct dm_shared_origin *dso = ti->private; + + ti->private = dso->origin_snap; + snapshot_dtr(ti); + kfree(dso); +} + +static int shared_origin_map(struct dm_target *ti, struct bio *bio, + union map_info *map_context) +{ + struct dm_shared_origin *dso = ti->private; + struct dm_dev *dev = dso->origin; + + bio->bi_bdev = dev->bdev; + + /* Only tell snapshots if this is a write */ + return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED; +} + +static int shared_origin_status(struct dm_target *ti, status_type_t type, + char *result, unsigned int maxlen) +{ + struct dm_shared_origin *dso = ti->private; + struct dm_snapshot *snap = dso->origin_snap; + struct exception_store *store = &snap->store; + unsigned long map[DIV_ROUND_UP(MAX_SNAPSHOTS, BITS_PER_LONG)]; + int r, nr, i; + + switch (type) { + case STATUSTYPE_INFO: + + memset(map, 0, sizeof(map)); + + down_write(&store->snap->lock); + nr = store->get_snapshot_info(store, map, sizeof(map)); + up_write(&store->snap->lock); + + if (nr) { + r = snprintf(result, maxlen, "%d ", nr); + result += r; + maxlen -= min_t(int, r, maxlen); + + for (i = 0; maxlen && i < MAX_SNAPSHOTS; i++) { + if (test_bit(i, map)) { + r = snprintf(result, maxlen, "%d ", i); + result += r; + maxlen -= min_t(int, r, maxlen); + } + } + } else + snprintf(result, maxlen, ": no snapshot"); + + break; + + case STATUSTYPE_TABLE: + r = snprintf(result, maxlen, "%s", snap->origin->name); + if (r > 0 && r < maxlen) + snprintf(result + r, maxlen - r, "%s %s %llu", + snap->origin->name, snap->cow->name, + (unsigned long long)snap->chunk_size); + break; + } + + return 0; +} + +static int shared_origin_message(struct dm_target *ti, unsigned argc, + char **argv) +{ + struct dm_shared_origin *dso = ti->private; + struct dm_snapshot *snap = dso->origin_snap; + return snap->store.message(&snap->store, argc, argv); +} + static struct target_type origin_target = { .name = "snapshot-origin", .version = {1, 6, 0}, @@ -1416,6 +1548,17 @@ static struct target_type snapshot_target = { .status = snapshot_status, }; +static struct target_type shared_origin_target = { + .name = "s-snap-origin", + .version = {1, 0, 0}, + .module = THIS_MODULE, + .ctr = shared_origin_ctr, + .dtr = shared_origin_dtr, + .map = shared_origin_map, + .status = shared_origin_status, + .message = shared_origin_message, +}; + static int __init dm_snapshot_init(void) { int r; @@ -1432,31 +1575,37 @@ static int __init dm_snapshot_init(void) goto bad1; } + r = dm_register_target(&shared_origin_target); + if (r) { + DMERR("shared origin target register failed %d", r); + goto bad2; + } + r = init_origin_hash(); if (r) { DMERR("init_origin_hash failed."); - goto bad2; + goto bad3; } exception_cache = KMEM_CACHE(dm_snap_exception, 0); if (!exception_cache) { DMERR("Couldn't create exception cache."); r = -ENOMEM; - goto bad3; + goto bad4; } pending_cache = KMEM_CACHE(dm_snap_pending_exception, 0); if (!pending_cache) { DMERR("Couldn't create pending cache."); r = -ENOMEM; - goto bad4; + goto bad5; } 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 bad5; + goto bad6; } ksnapd = create_singlethread_workqueue("ksnapd"); @@ -1470,12 +1619,14 @@ static int __init dm_snapshot_init(void) bad_pending_pool: kmem_cache_destroy(tracked_chunk_cache); - bad5: + bad6: kmem_cache_destroy(pending_cache); - bad4: + bad5: kmem_cache_destroy(exception_cache); - bad3: + bad4: exit_origin_hash(); + bad3: + dm_unregister_target(&shared_origin_target); bad2: dm_unregister_target(&origin_target); bad1: @@ -1497,6 +1648,10 @@ static void __exit dm_snapshot_exit(void) if (r) DMERR("origin unregister failed %d", r); + r = dm_unregister_target(&shared_origin_target); + if (r) + DMERR("shared origin unregister failed %d", r); + exit_origin_hash(); kmem_cache_destroy(pending_cache); kmem_cache_destroy(exception_cache); -- 1.5.5.GIT