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dm exception store: move chunk_fields

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Move chunk fields from snapshot to exception store.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Jonathan Brassow
2009-04-02 19:55:32 +01:00
committed by Alasdair G Kergon
parent 0cea9c7827
commit d021684951
6 changed files with 67 additions and 53 deletions
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47
drivers/md/dm-snap.c
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@@ -468,7 +468,7 @@ static int calc_max_buckets(void)
/*
* Allocate room for a suitable hash table.
*/
static int init_hash_tables(struct dm_snapshot *s)
static int init_hash_tables(struct dm_snapshot *s, chunk_t chunk_shift)
{
sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets;
@@ -480,7 +480,7 @@ static int init_hash_tables(struct dm_snapshot *s)
origin_dev_size = get_dev_size(s->origin->bdev);
max_buckets = calc_max_buckets();
hash_size = min(origin_dev_size, cow_dev_size) >> s->chunk_shift;
hash_size = min(origin_dev_size, cow_dev_size) >> chunk_shift;
hash_size = min(hash_size, max_buckets);
hash_size = rounddown_pow_of_two(hash_size);
@@ -515,19 +515,20 @@ static ulong round_up(ulong n, ulong size)
}
static int set_chunk_size(struct dm_snapshot *s, const char *chunk_size_arg,
char **error)
chunk_t *chunk_size, chunk_t *chunk_mask,
chunk_t *chunk_shift, char **error)
{
unsigned long chunk_size;
unsigned long chunk_size_ulong;
char *value;
chunk_size = simple_strtoul(chunk_size_arg, &value, 10);
chunk_size_ulong = simple_strtoul(chunk_size_arg, &value, 10);
if (*chunk_size_arg == '\0' || *value != '\0') {
*error = "Invalid chunk size";
return -EINVAL;
}
if (!chunk_size) {
s->chunk_size = s->chunk_mask = s->chunk_shift = 0;
if (!chunk_size_ulong) {
*chunk_size = *chunk_mask = *chunk_shift = 0;
return 0;
}
@@ -535,23 +536,23 @@ static int set_chunk_size(struct dm_snapshot *s, const char *chunk_size_arg,
* Chunk size must be multiple of page size. Silently
* round up if it's not.
*/
chunk_size = round_up(chunk_size, PAGE_SIZE >> 9);
chunk_size_ulong = round_up(chunk_size_ulong, PAGE_SIZE >> 9);
/* Check chunk_size is a power of 2 */
if (!is_power_of_2(chunk_size)) {
if (!is_power_of_2(chunk_size_ulong)) {
*error = "Chunk size is not a power of 2";
return -EINVAL;
}
/* Validate the chunk size against the device block size */
if (chunk_size % (bdev_hardsect_size(s->cow->bdev) >> 9)) {
if (chunk_size_ulong % (bdev_hardsect_size(s->cow->bdev) >> 9)) {
*error = "Chunk size is not a multiple of device blocksize";
return -EINVAL;
}
s->chunk_size = chunk_size;
s->chunk_mask = chunk_size - 1;
s->chunk_shift = ffs(chunk_size) - 1;
*chunk_size = chunk_size_ulong;
*chunk_mask = chunk_size_ulong - 1;
*chunk_shift = ffs(chunk_size_ulong) - 1;
return 0;
}
@@ -567,6 +568,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
char persistent;
char *origin_path;
char *cow_path;
chunk_t chunk_size, chunk_mask, chunk_shift;
if (argc != 4) {
ti->error = "requires exactly 4 arguments";
@@ -606,7 +608,8 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad2;
}
r = set_chunk_size(s, argv[3], &ti->error);
r = set_chunk_size(s, argv[3], &chunk_size, &chunk_mask, &chunk_shift,
&ti->error);
if (r)
goto bad3;
@@ -617,13 +620,14 @@ 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)) {
if (init_hash_tables(s, chunk_shift)) {
ti->error = "Unable to allocate hash table space";
r = -ENOMEM;
goto bad3;
}
r = dm_exception_store_create(argv[2], ti, &s->store);
r = dm_exception_store_create(argv[2], ti, chunk_size, chunk_mask,
chunk_shift, &s->store);
if (r) {
ti->error = "Couldn't create exception store";
r = -EINVAL;
@@ -680,7 +684,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
}
ti->private = s;
ti->split_io = s->chunk_size;
ti->split_io = s->store->chunk_size;
return 0;
@@ -955,7 +959,7 @@ static void start_copy(struct dm_snap_pending_exception *pe)
src.bdev = bdev;
src.sector = chunk_to_sector(s, pe->e.old_chunk);
src.count = min(s->chunk_size, dev_size - src.sector);
src.count = min(s->store->chunk_size, dev_size - src.sector);
dest.bdev = s->cow->bdev;
dest.sector = chunk_to_sector(s, pe->e.new_chunk);
@@ -1021,7 +1025,7 @@ static void remap_exception(struct dm_snapshot *s, struct dm_snap_exception *e,
bio->bi_bdev = s->cow->bdev;
bio->bi_sector = chunk_to_sector(s, dm_chunk_number(e->new_chunk) +
(chunk - e->old_chunk)) +
(bio->bi_sector & s->chunk_mask);
(bio->bi_sector & s->store->chunk_mask);
}
static int snapshot_map(struct dm_target *ti, struct bio *bio,
@@ -1166,7 +1170,7 @@ static int snapshot_status(struct dm_target *ti, status_type_t type,
snprintf(result, maxlen, "%s %s %s %llu",
snap->origin->name, snap->cow->name,
snap->store->type->name,
(unsigned long long)snap->chunk_size);
(unsigned long long)snap->store->chunk_size);
break;
}
@@ -1377,7 +1381,8 @@ static void origin_resume(struct dm_target *ti)
o = __lookup_origin(dev->bdev);
if (o)
list_for_each_entry (snap, &o->snapshots, list)
chunk_size = min_not_zero(chunk_size, snap->chunk_size);
chunk_size = min_not_zero(chunk_size,
snap->store->chunk_size);
up_read(&_origins_lock);
ti->split_io = chunk_size;