From 49beb2b87a972a994ff77633234ca3bf0d30a1d8 Mon Sep 17 00:00:00 2001 From: Jonathan Brassow Date: Thu, 2 Apr 2009 19:55:33 +0100 Subject: [PATCH] dm exception store: move cow pointer Move COW device from snapshot to exception store. Signed-off-by: Jonathan Brassow Signed-off-by: Alasdair G Kergon --- drivers/md/dm-exception-store.c | 4 +++- drivers/md/dm-exception-store.h | 4 +++- drivers/md/dm-snap-persistent.c | 10 +++++----- drivers/md/dm-snap-transient.c | 4 ++-- drivers/md/dm-snap.c | 30 +++++++++++++++++------------- drivers/md/dm-snap.h | 1 - 6 files changed, 30 insertions(+), 23 deletions(-) diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c index 59c949b53106..2078b92470a1 100644 --- a/drivers/md/dm-exception-store.c +++ b/drivers/md/dm-exception-store.c @@ -139,7 +139,7 @@ EXPORT_SYMBOL(dm_exception_store_type_unregister); int dm_exception_store_create(const char *type_name, struct dm_target *ti, chunk_t chunk_size, chunk_t chunk_mask, - chunk_t chunk_shift, + chunk_t chunk_shift, struct dm_dev *cow, struct dm_exception_store **store) { int r = 0; @@ -163,6 +163,8 @@ int dm_exception_store_create(const char *type_name, struct dm_target *ti, tmp_store->chunk_mask = chunk_mask; tmp_store->chunk_shift = chunk_shift; + tmp_store->cow = cow; + r = type->ctr(tmp_store, 0, NULL); if (r) { put_type(type); diff --git a/drivers/md/dm-exception-store.h b/drivers/md/dm-exception-store.h index 449a1e48f7aa..4dbf3577408e 100644 --- a/drivers/md/dm-exception-store.h +++ b/drivers/md/dm-exception-store.h @@ -99,6 +99,8 @@ struct dm_exception_store { struct dm_snapshot *snap; + struct dm_dev *cow; + /* Size of data blocks saved - must be a power of 2 */ chunk_t chunk_size; chunk_t chunk_mask; @@ -155,7 +157,7 @@ int dm_exception_store_type_unregister(struct dm_exception_store_type *type); int dm_exception_store_create(const char *type_name, struct dm_target *ti, chunk_t chunk_size, chunk_t chunk_mask, - chunk_t chunk_shift, + chunk_t chunk_shift, struct dm_dev *cow, struct dm_exception_store **store); void dm_exception_store_destroy(struct dm_exception_store *store); diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c index c3c58159b6e8..505afac9976f 100644 --- a/drivers/md/dm-snap-persistent.c +++ b/drivers/md/dm-snap-persistent.c @@ -189,7 +189,7 @@ static void do_metadata(struct work_struct *work) static int chunk_io(struct pstore *ps, chunk_t chunk, int rw, int metadata) { struct dm_io_region where = { - .bdev = ps->snap->cow->bdev, + .bdev = ps->snap->store->cow->bdev, .sector = ps->snap->store->chunk_size * chunk, .count = ps->snap->store->chunk_size, }; @@ -253,7 +253,7 @@ static void zero_memory_area(struct pstore *ps) static int zero_disk_area(struct pstore *ps, chunk_t area) { struct dm_io_region where = { - .bdev = ps->snap->cow->bdev, + .bdev = ps->snap->store->cow->bdev, .sector = ps->snap->store->chunk_size * area_location(ps, area), .count = ps->snap->store->chunk_size, }; @@ -280,7 +280,7 @@ static int read_header(struct pstore *ps, int *new_snapshot) */ if (!ps->snap->store->chunk_size) { ps->snap->store->chunk_size = max(DM_CHUNK_SIZE_DEFAULT_SECTORS, - bdev_hardsect_size(ps->snap->cow->bdev) >> 9); + bdev_hardsect_size(ps->snap->store->cow->bdev) >> 9); ps->snap->store->chunk_mask = ps->snap->store->chunk_size - 1; ps->snap->store->chunk_shift = ffs(ps->snap->store->chunk_size) - 1; @@ -476,7 +476,7 @@ static void persistent_fraction_full(struct dm_exception_store *store, sector_t *numerator, sector_t *denominator) { *numerator = get_info(store)->next_free * store->chunk_size; - *denominator = get_dev_size(store->snap->cow->bdev); + *denominator = get_dev_size(store->cow->bdev); } static void persistent_dtr(struct dm_exception_store *store) @@ -565,7 +565,7 @@ static int persistent_prepare_exception(struct dm_exception_store *store, struct pstore *ps = get_info(store); uint32_t stride; chunk_t next_free; - sector_t size = get_dev_size(store->snap->cow->bdev); + sector_t size = get_dev_size(store->cow->bdev); /* Is there enough room ? */ if (size < ((ps->next_free + 1) * store->chunk_size)) diff --git a/drivers/md/dm-snap-transient.c b/drivers/md/dm-snap-transient.c index c542ababb418..77f58be080c4 100644 --- a/drivers/md/dm-snap-transient.c +++ b/drivers/md/dm-snap-transient.c @@ -40,7 +40,7 @@ static int transient_prepare_exception(struct dm_exception_store *store, struct dm_snap_exception *e) { struct transient_c *tc = store->context; - sector_t size = get_dev_size(store->snap->cow->bdev); + sector_t size = get_dev_size(store->cow->bdev); if (size < (tc->next_free + store->chunk_size)) return -1; @@ -64,7 +64,7 @@ static void transient_fraction_full(struct dm_exception_store *store, sector_t *numerator, sector_t *denominator) { *numerator = ((struct transient_c *) store->context)->next_free; - *denominator = get_dev_size(store->snap->cow->bdev); + *denominator = get_dev_size(store->cow->bdev); } static int transient_ctr(struct dm_exception_store *store, diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index 7a90fed033fe..5c067efc665f 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -468,7 +468,8 @@ static int calc_max_buckets(void) /* * Allocate room for a suitable hash table. */ -static int init_hash_tables(struct dm_snapshot *s, chunk_t chunk_shift) +static int init_hash_tables(struct dm_snapshot *s, chunk_t chunk_shift, + struct dm_dev *cow) { sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets; @@ -476,7 +477,7 @@ static int init_hash_tables(struct dm_snapshot *s, chunk_t chunk_shift) * Calculate based on the size of the original volume or * the COW volume... */ - cow_dev_size = get_dev_size(s->cow->bdev); + cow_dev_size = get_dev_size(cow->bdev); origin_dev_size = get_dev_size(s->origin->bdev); max_buckets = calc_max_buckets(); @@ -516,7 +517,8 @@ static ulong round_up(ulong n, ulong size) static int set_chunk_size(struct dm_snapshot *s, const char *chunk_size_arg, chunk_t *chunk_size, chunk_t *chunk_mask, - chunk_t *chunk_shift, char **error) + chunk_t *chunk_shift, struct dm_dev *cow, + char **error) { unsigned long chunk_size_ulong; char *value; @@ -545,7 +547,7 @@ static int set_chunk_size(struct dm_snapshot *s, const char *chunk_size_arg, } /* Validate the chunk size against the device block size */ - if (chunk_size_ulong % (bdev_hardsect_size(s->cow->bdev) >> 9)) { + if (chunk_size_ulong % (bdev_hardsect_size(cow->bdev) >> 9)) { *error = "Chunk size is not a multiple of device blocksize"; return -EINVAL; } @@ -569,6 +571,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) char *origin_path; char *cow_path; chunk_t chunk_size, chunk_mask, chunk_shift; + struct dm_dev *cow; if (argc != 4) { ti->error = "requires exactly 4 arguments"; @@ -601,7 +604,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) } r = dm_get_device(ti, cow_path, 0, 0, - FMODE_READ | FMODE_WRITE, &s->cow); + FMODE_READ | FMODE_WRITE, &cow); if (r) { dm_put_device(ti, s->origin); ti->error = "Cannot get COW device"; @@ -609,7 +612,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) } r = set_chunk_size(s, argv[3], &chunk_size, &chunk_mask, &chunk_shift, - &ti->error); + cow, &ti->error); if (r) goto bad3; @@ -620,14 +623,14 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) spin_lock_init(&s->pe_lock); /* Allocate hash table for COW data */ - if (init_hash_tables(s, chunk_shift)) { + if (init_hash_tables(s, chunk_shift, cow)) { ti->error = "Unable to allocate hash table space"; r = -ENOMEM; goto bad3; } r = dm_exception_store_create(argv[2], ti, chunk_size, chunk_mask, - chunk_shift, &s->store); + chunk_shift, cow, &s->store); if (r) { ti->error = "Couldn't create exception store"; r = -EINVAL; @@ -705,7 +708,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) exit_exception_table(&s->complete, exception_cache); bad3: - dm_put_device(ti, s->cow); + dm_put_device(ti, cow); dm_put_device(ti, s->origin); bad2: @@ -732,6 +735,7 @@ static void snapshot_dtr(struct dm_target *ti) int i; #endif struct dm_snapshot *s = ti->private; + struct dm_dev *cow = s->store->cow; flush_workqueue(ksnapd); @@ -759,7 +763,7 @@ static void snapshot_dtr(struct dm_target *ti) mempool_destroy(s->pending_pool); dm_put_device(ti, s->origin); - dm_put_device(ti, s->cow); + dm_put_device(ti, cow); kfree(s); } @@ -961,7 +965,7 @@ static void start_copy(struct dm_snap_pending_exception *pe) src.sector = chunk_to_sector(s, pe->e.old_chunk); src.count = min(s->store->chunk_size, dev_size - src.sector); - dest.bdev = s->cow->bdev; + dest.bdev = s->store->cow->bdev; dest.sector = chunk_to_sector(s, pe->e.new_chunk); dest.count = src.count; @@ -1022,7 +1026,7 @@ __find_pending_exception(struct dm_snapshot *s, static void remap_exception(struct dm_snapshot *s, struct dm_snap_exception *e, struct bio *bio, chunk_t chunk) { - bio->bi_bdev = s->cow->bdev; + bio->bi_bdev = s->store->cow->bdev; bio->bi_sector = chunk_to_sector(s, dm_chunk_number(e->new_chunk) + (chunk - e->old_chunk)) + (bio->bi_sector & s->store->chunk_mask); @@ -1168,7 +1172,7 @@ static int snapshot_status(struct dm_target *ti, status_type_t type, * make sense. */ snprintf(result, maxlen, "%s %s %s %llu", - snap->origin->name, snap->cow->name, + snap->origin->name, snap->store->cow->name, snap->store->type->name, (unsigned long long)snap->store->chunk_size); break; diff --git a/drivers/md/dm-snap.h b/drivers/md/dm-snap.h index c2e4ebedbd49..c8a486e0ea2c 100644 --- a/drivers/md/dm-snap.h +++ b/drivers/md/dm-snap.h @@ -27,7 +27,6 @@ struct dm_snapshot { struct rw_semaphore lock; struct dm_dev *origin; - struct dm_dev *cow; /* List of snapshots per Origin */ struct list_head list;