X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=drivers%2Fmd%2Fdm-snap.c;h=1ba8a47d61b116646c6ac8ef533cd5b8f64767a7;hb=908cf4b925e419bc74f3297b2f0e51d6f8a81da2;hp=cee16fadd9ee70379449ce995ac4043d1ff86e5f;hpb=786d3693f46579c7cd982e65de9f43eba94e4a57;p=pandora-kernel.git diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index cee16fadd9ee..1ba8a47d61b1 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -18,10 +18,10 @@ #include #include #include +#include #include "dm-snap.h" #include "dm-bio-list.h" -#include "kcopyd.h" #define DM_MSG_PREFIX "snapshots" @@ -36,9 +36,9 @@ #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); @@ -213,11 +213,15 @@ static void unregister_snapshot(struct dm_snapshot *s) /* * 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) @@ -248,7 +252,7 @@ static void exit_exception_table(struct exception_table *et, struct kmem_cache * 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, @@ -275,7 +279,8 @@ static struct dm_snap_exception *lookup_exception(struct exception_table *et, 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; @@ -307,6 +312,49 @@ static void free_pending_exception(struct dm_snap_pending_exception *pe) 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; @@ -316,8 +364,12 @@ int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new) 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; } @@ -333,16 +385,6 @@ static int calc_max_buckets(void) 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. */ @@ -361,9 +403,9 @@ static int init_hash_tables(struct dm_snapshot *s) 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; /* @@ -374,7 +416,7 @@ static int init_hash_tables(struct dm_snapshot *s) 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; } @@ -494,7 +536,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) 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)) { @@ -516,7 +558,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) 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; @@ -549,7 +591,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) return 0; bad6: - kcopyd_client_destroy(s->kcopyd_client); + dm_kcopyd_client_destroy(s->kcopyd_client); bad5: s->store.destroy(&s->store); @@ -571,7 +613,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) 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); @@ -657,7 +699,7 @@ static void __invalidate_snapshot(struct dm_snapshot *s, int err) 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) @@ -733,7 +775,7 @@ static void pending_complete(struct dm_snap_pending_exception *pe, int success) * 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); @@ -762,7 +804,7 @@ static void commit_callback(void *context, int success) * 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; @@ -782,7 +824,7 @@ static void copy_callback(int read_err, unsigned int write_err, void *context) 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; @@ -797,7 +839,7 @@ static void start_copy(struct dm_snap_pending_exception *pe) 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); } @@ -867,11 +909,12 @@ __find_pending_exception(struct dm_snapshot *s, struct bio *bio) } 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, @@ -902,7 +945,7 @@ 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; } @@ -919,7 +962,7 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio, 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; @@ -1017,7 +1060,7 @@ static int __origin_write(struct list_head *snapshots, struct bio *bio) 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; /* @@ -1207,7 +1250,7 @@ static int origin_status(struct dm_target *ti, status_type_t type, char *result, 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, @@ -1218,7 +1261,7 @@ static struct target_type origin_target = { 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,