#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/log2.h>
+#include <linux/dm-kcopyd.h>
#include "dm-snap.h"
#include "dm-bio-list.h"
-#include "kcopyd.h"
#define DM_MSG_PREFIX "snapshots"
#define SNAPSHOT_COPY_PRIORITY 2
/*
- * Each snapshot reserves this many pages for io
+ * Reserve 1MB for each snapshot initially (with minimum of 1 page).
*/
-#define SNAPSHOT_PAGES 256
+#define SNAPSHOT_PAGES (((1UL << 20) >> PAGE_SHIFT) ? : 1)
static struct workqueue_struct *ksnapd;
static void flush_queued_bios(struct work_struct *work);
/*
* Implementation of the exception hash tables.
+ * The lowest hash_shift bits of the chunk number are ignored, allowing
+ * some consecutive chunks to be grouped together.
*/
-static int init_exception_table(struct exception_table *et, uint32_t size)
+static int init_exception_table(struct exception_table *et, uint32_t size,
+ unsigned hash_shift)
{
unsigned int i;
+ et->hash_shift = hash_shift;
et->hash_mask = size - 1;
et->table = dm_vcalloc(size, sizeof(struct list_head));
if (!et->table)
static uint32_t exception_hash(struct exception_table *et, chunk_t chunk)
{
- return chunk & et->hash_mask;
+ return (chunk >> et->hash_shift) & et->hash_mask;
}
static void insert_exception(struct exception_table *eh,
slot = &et->table[exception_hash(et, chunk)];
list_for_each_entry (e, slot, hash_list)
- if (e->old_chunk == chunk)
+ if (chunk >= e->old_chunk &&
+ chunk <= e->old_chunk + dm_consecutive_chunk_count(e))
return e;
return NULL;
mempool_free(pe, pending_pool);
}
+static void insert_completed_exception(struct dm_snapshot *s,
+ struct dm_snap_exception *new_e)
+{
+ struct exception_table *eh = &s->complete;
+ struct list_head *l;
+ struct dm_snap_exception *e = NULL;
+
+ l = &eh->table[exception_hash(eh, new_e->old_chunk)];
+
+ /* Add immediately if this table doesn't support consecutive chunks */
+ if (!eh->hash_shift)
+ goto out;
+
+ /* List is ordered by old_chunk */
+ list_for_each_entry_reverse(e, l, hash_list) {
+ /* Insert after an existing chunk? */
+ if (new_e->old_chunk == (e->old_chunk +
+ dm_consecutive_chunk_count(e) + 1) &&
+ new_e->new_chunk == (dm_chunk_number(e->new_chunk) +
+ dm_consecutive_chunk_count(e) + 1)) {
+ dm_consecutive_chunk_count_inc(e);
+ free_exception(new_e);
+ return;
+ }
+
+ /* Insert before an existing chunk? */
+ if (new_e->old_chunk == (e->old_chunk - 1) &&
+ new_e->new_chunk == (dm_chunk_number(e->new_chunk) - 1)) {
+ dm_consecutive_chunk_count_inc(e);
+ e->old_chunk--;
+ e->new_chunk--;
+ free_exception(new_e);
+ return;
+ }
+
+ if (new_e->old_chunk > e->old_chunk)
+ break;
+ }
+
+out:
+ list_add(&new_e->hash_list, e ? &e->hash_list : l);
+}
+
int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new)
{
struct dm_snap_exception *e;
return -ENOMEM;
e->old_chunk = old;
+
+ /* Consecutive_count is implicitly initialised to zero */
e->new_chunk = new;
- insert_exception(&s->complete, e);
+
+ insert_completed_exception(s, e);
+
return 0;
}
return mem;
}
-/*
- * Rounds a number down to a power of 2.
- */
-static uint32_t round_down(uint32_t n)
-{
- while (n & (n - 1))
- n &= (n - 1);
- return n;
-}
-
/*
* Allocate room for a suitable hash table.
*/
hash_size = min(origin_dev_size, cow_dev_size) >> s->chunk_shift;
hash_size = min(hash_size, max_buckets);
- /* Round it down to a power of 2 */
- hash_size = round_down(hash_size);
- if (init_exception_table(&s->complete, hash_size))
+ hash_size = rounddown_pow_of_two(hash_size);
+ if (init_exception_table(&s->complete, hash_size,
+ DM_CHUNK_CONSECUTIVE_BITS))
return -ENOMEM;
/*
if (hash_size < 64)
hash_size = 64;
- if (init_exception_table(&s->pending, hash_size)) {
+ if (init_exception_table(&s->pending, hash_size, 0)) {
exit_exception_table(&s->complete, exception_cache);
return -ENOMEM;
}
s->last_percent = 0;
init_rwsem(&s->lock);
spin_lock_init(&s->pe_lock);
- s->table = ti->table;
+ s->ti = ti;
/* Allocate hash table for COW data */
if (init_hash_tables(s)) {
goto bad4;
}
- r = kcopyd_client_create(SNAPSHOT_PAGES, &s->kcopyd_client);
+ r = dm_kcopyd_client_create(SNAPSHOT_PAGES, &s->kcopyd_client);
if (r) {
ti->error = "Could not create kcopyd client";
goto bad5;
return 0;
bad6:
- kcopyd_client_destroy(s->kcopyd_client);
+ dm_kcopyd_client_destroy(s->kcopyd_client);
bad5:
s->store.destroy(&s->store);
static void __free_exceptions(struct dm_snapshot *s)
{
- kcopyd_client_destroy(s->kcopyd_client);
+ dm_kcopyd_client_destroy(s->kcopyd_client);
s->kcopyd_client = NULL;
exit_exception_table(&s->pending, pending_cache);
s->valid = 0;
- dm_table_event(s->table);
+ dm_table_event(s->ti->table);
}
static void get_pending_exception(struct dm_snap_pending_exception *pe)
* Add a proper exception, and remove the
* in-flight exception from the list.
*/
- insert_exception(&s->complete, e);
+ insert_completed_exception(s, e);
out:
remove_exception(&pe->e);
* Called when the copy I/O has finished. kcopyd actually runs
* this code so don't block.
*/
-static void copy_callback(int read_err, unsigned int write_err, void *context)
+static void copy_callback(int read_err, unsigned long write_err, void *context)
{
struct dm_snap_pending_exception *pe = context;
struct dm_snapshot *s = pe->snap;
static void start_copy(struct dm_snap_pending_exception *pe)
{
struct dm_snapshot *s = pe->snap;
- struct io_region src, dest;
+ struct dm_io_region src, dest;
struct block_device *bdev = s->origin->bdev;
sector_t dev_size;
dest.count = src.count;
/* Hand over to kcopyd */
- kcopyd_copy(s->kcopyd_client,
+ dm_kcopyd_copy(s->kcopyd_client,
&src, 1, &dest, 0, copy_callback, pe);
}
}
static void remap_exception(struct dm_snapshot *s, struct dm_snap_exception *e,
- struct bio *bio)
+ struct bio *bio, chunk_t chunk)
{
bio->bi_bdev = s->cow->bdev;
- bio->bi_sector = chunk_to_sector(s, e->new_chunk) +
- (bio->bi_sector & s->chunk_mask);
+ bio->bi_sector = chunk_to_sector(s, dm_chunk_number(e->new_chunk) +
+ (chunk - e->old_chunk)) +
+ (bio->bi_sector & s->chunk_mask);
}
static int snapshot_map(struct dm_target *ti, struct bio *bio,
/* If the block is already remapped - use that, else remap it */
e = lookup_exception(&s->complete, chunk);
if (e) {
- remap_exception(s, e, bio);
+ remap_exception(s, e, bio, chunk);
goto out_unlock;
}
goto out_unlock;
}
- remap_exception(s, &pe->e, bio);
+ remap_exception(s, &pe->e, bio, chunk);
bio_list_add(&pe->snapshot_bios, bio);
r = DM_MAPIO_SUBMITTED;
goto next_snapshot;
/* Nothing to do if writing beyond end of snapshot */
- if (bio->bi_sector >= dm_table_get_size(snap->table))
+ if (bio->bi_sector >= dm_table_get_size(snap->ti->table))
goto next_snapshot;
/*
static struct target_type origin_target = {
.name = "snapshot-origin",
- .version = {1, 5, 0},
+ .version = {1, 6, 0},
.module = THIS_MODULE,
.ctr = origin_ctr,
.dtr = origin_dtr,
static struct target_type snapshot_target = {
.name = "snapshot",
- .version = {1, 5, 0},
+ .version = {1, 6, 0},
.module = THIS_MODULE,
.ctr = snapshot_ctr,
.dtr = snapshot_dtr,
git.openpandora.org / pandora-kernel.git / blobdiff