11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * dm-snapshot.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Copyright (C) 2001-2002 Sistina Software (UK) Limited. 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * This file is released under the GPL. 71da177e4SLinus Torvalds */ 81da177e4SLinus Torvalds 91da177e4SLinus Torvalds #include <linux/blkdev.h> 101da177e4SLinus Torvalds #include <linux/config.h> 111da177e4SLinus Torvalds #include <linux/ctype.h> 121da177e4SLinus Torvalds #include <linux/device-mapper.h> 131da177e4SLinus Torvalds #include <linux/fs.h> 141da177e4SLinus Torvalds #include <linux/init.h> 151da177e4SLinus Torvalds #include <linux/kdev_t.h> 161da177e4SLinus Torvalds #include <linux/list.h> 171da177e4SLinus Torvalds #include <linux/mempool.h> 181da177e4SLinus Torvalds #include <linux/module.h> 191da177e4SLinus Torvalds #include <linux/slab.h> 201da177e4SLinus Torvalds #include <linux/vmalloc.h> 211da177e4SLinus Torvalds 221da177e4SLinus Torvalds #include "dm-snap.h" 231da177e4SLinus Torvalds #include "dm-bio-list.h" 241da177e4SLinus Torvalds #include "kcopyd.h" 251da177e4SLinus Torvalds 261da177e4SLinus Torvalds /* 271da177e4SLinus Torvalds * The percentage increment we will wake up users at 281da177e4SLinus Torvalds */ 291da177e4SLinus Torvalds #define WAKE_UP_PERCENT 5 301da177e4SLinus Torvalds 311da177e4SLinus Torvalds /* 321da177e4SLinus Torvalds * kcopyd priority of snapshot operations 331da177e4SLinus Torvalds */ 341da177e4SLinus Torvalds #define SNAPSHOT_COPY_PRIORITY 2 351da177e4SLinus Torvalds 361da177e4SLinus Torvalds /* 371da177e4SLinus Torvalds * Each snapshot reserves this many pages for io 381da177e4SLinus Torvalds */ 391da177e4SLinus Torvalds #define SNAPSHOT_PAGES 256 401da177e4SLinus Torvalds 411da177e4SLinus Torvalds struct pending_exception { 421da177e4SLinus Torvalds struct exception e; 431da177e4SLinus Torvalds 441da177e4SLinus Torvalds /* 451da177e4SLinus Torvalds * Origin buffers waiting for this to complete are held 461da177e4SLinus Torvalds * in a bio list 471da177e4SLinus Torvalds */ 481da177e4SLinus Torvalds struct bio_list origin_bios; 491da177e4SLinus Torvalds struct bio_list snapshot_bios; 501da177e4SLinus Torvalds 511da177e4SLinus Torvalds /* 52eccf0817SAlasdair G Kergon * Short-term queue of pending exceptions prior to submission. 53eccf0817SAlasdair G Kergon */ 54eccf0817SAlasdair G Kergon struct list_head list; 55eccf0817SAlasdair G Kergon 56eccf0817SAlasdair G Kergon /* 57b4b610f6SAlasdair G Kergon * The primary pending_exception is the one that holds 58b4b610f6SAlasdair G Kergon * the sibling_count and the list of origin_bios for a 59b4b610f6SAlasdair G Kergon * group of pending_exceptions. It is always last to get freed. 60b4b610f6SAlasdair G Kergon * These fields get set up when writing to the origin. 611da177e4SLinus Torvalds */ 62b4b610f6SAlasdair G Kergon struct pending_exception *primary_pe; 63b4b610f6SAlasdair G Kergon 64b4b610f6SAlasdair G Kergon /* 65b4b610f6SAlasdair G Kergon * Number of pending_exceptions processing this chunk. 66b4b610f6SAlasdair G Kergon * When this drops to zero we must complete the origin bios. 67b4b610f6SAlasdair G Kergon * If incrementing or decrementing this, hold pe->snap->lock for 68b4b610f6SAlasdair G Kergon * the sibling concerned and not pe->primary_pe->snap->lock unless 69b4b610f6SAlasdair G Kergon * they are the same. 70b4b610f6SAlasdair G Kergon */ 71b4b610f6SAlasdair G Kergon atomic_t sibling_count; 721da177e4SLinus Torvalds 731da177e4SLinus Torvalds /* Pointer back to snapshot context */ 741da177e4SLinus Torvalds struct dm_snapshot *snap; 751da177e4SLinus Torvalds 761da177e4SLinus Torvalds /* 771da177e4SLinus Torvalds * 1 indicates the exception has already been sent to 781da177e4SLinus Torvalds * kcopyd. 791da177e4SLinus Torvalds */ 801da177e4SLinus Torvalds int started; 811da177e4SLinus Torvalds }; 821da177e4SLinus Torvalds 831da177e4SLinus Torvalds /* 841da177e4SLinus Torvalds * Hash table mapping origin volumes to lists of snapshots and 851da177e4SLinus Torvalds * a lock to protect it 861da177e4SLinus Torvalds */ 871da177e4SLinus Torvalds static kmem_cache_t *exception_cache; 881da177e4SLinus Torvalds static kmem_cache_t *pending_cache; 891da177e4SLinus Torvalds static mempool_t *pending_pool; 901da177e4SLinus Torvalds 911da177e4SLinus Torvalds /* 921da177e4SLinus Torvalds * One of these per registered origin, held in the snapshot_origins hash 931da177e4SLinus Torvalds */ 941da177e4SLinus Torvalds struct origin { 951da177e4SLinus Torvalds /* The origin device */ 961da177e4SLinus Torvalds struct block_device *bdev; 971da177e4SLinus Torvalds 981da177e4SLinus Torvalds struct list_head hash_list; 991da177e4SLinus Torvalds 1001da177e4SLinus Torvalds /* List of snapshots for this origin */ 1011da177e4SLinus Torvalds struct list_head snapshots; 1021da177e4SLinus Torvalds }; 1031da177e4SLinus Torvalds 1041da177e4SLinus Torvalds /* 1051da177e4SLinus Torvalds * Size of the hash table for origin volumes. If we make this 1061da177e4SLinus Torvalds * the size of the minors list then it should be nearly perfect 1071da177e4SLinus Torvalds */ 1081da177e4SLinus Torvalds #define ORIGIN_HASH_SIZE 256 1091da177e4SLinus Torvalds #define ORIGIN_MASK 0xFF 1101da177e4SLinus Torvalds static struct list_head *_origins; 1111da177e4SLinus Torvalds static struct rw_semaphore _origins_lock; 1121da177e4SLinus Torvalds 1131da177e4SLinus Torvalds static int init_origin_hash(void) 1141da177e4SLinus Torvalds { 1151da177e4SLinus Torvalds int i; 1161da177e4SLinus Torvalds 1171da177e4SLinus Torvalds _origins = kmalloc(ORIGIN_HASH_SIZE * sizeof(struct list_head), 1181da177e4SLinus Torvalds GFP_KERNEL); 1191da177e4SLinus Torvalds if (!_origins) { 1201da177e4SLinus Torvalds DMERR("Device mapper: Snapshot: unable to allocate memory"); 1211da177e4SLinus Torvalds return -ENOMEM; 1221da177e4SLinus Torvalds } 1231da177e4SLinus Torvalds 1241da177e4SLinus Torvalds for (i = 0; i < ORIGIN_HASH_SIZE; i++) 1251da177e4SLinus Torvalds INIT_LIST_HEAD(_origins + i); 1261da177e4SLinus Torvalds init_rwsem(&_origins_lock); 1271da177e4SLinus Torvalds 1281da177e4SLinus Torvalds return 0; 1291da177e4SLinus Torvalds } 1301da177e4SLinus Torvalds 1311da177e4SLinus Torvalds static void exit_origin_hash(void) 1321da177e4SLinus Torvalds { 1331da177e4SLinus Torvalds kfree(_origins); 1341da177e4SLinus Torvalds } 1351da177e4SLinus Torvalds 1361da177e4SLinus Torvalds static inline unsigned int origin_hash(struct block_device *bdev) 1371da177e4SLinus Torvalds { 1381da177e4SLinus Torvalds return bdev->bd_dev & ORIGIN_MASK; 1391da177e4SLinus Torvalds } 1401da177e4SLinus Torvalds 1411da177e4SLinus Torvalds static struct origin *__lookup_origin(struct block_device *origin) 1421da177e4SLinus Torvalds { 1431da177e4SLinus Torvalds struct list_head *ol; 1441da177e4SLinus Torvalds struct origin *o; 1451da177e4SLinus Torvalds 1461da177e4SLinus Torvalds ol = &_origins[origin_hash(origin)]; 1471da177e4SLinus Torvalds list_for_each_entry (o, ol, hash_list) 1481da177e4SLinus Torvalds if (bdev_equal(o->bdev, origin)) 1491da177e4SLinus Torvalds return o; 1501da177e4SLinus Torvalds 1511da177e4SLinus Torvalds return NULL; 1521da177e4SLinus Torvalds } 1531da177e4SLinus Torvalds 1541da177e4SLinus Torvalds static void __insert_origin(struct origin *o) 1551da177e4SLinus Torvalds { 1561da177e4SLinus Torvalds struct list_head *sl = &_origins[origin_hash(o->bdev)]; 1571da177e4SLinus Torvalds list_add_tail(&o->hash_list, sl); 1581da177e4SLinus Torvalds } 1591da177e4SLinus Torvalds 1601da177e4SLinus Torvalds /* 1611da177e4SLinus Torvalds * Make a note of the snapshot and its origin so we can look it 1621da177e4SLinus Torvalds * up when the origin has a write on it. 1631da177e4SLinus Torvalds */ 1641da177e4SLinus Torvalds static int register_snapshot(struct dm_snapshot *snap) 1651da177e4SLinus Torvalds { 1661da177e4SLinus Torvalds struct origin *o; 1671da177e4SLinus Torvalds struct block_device *bdev = snap->origin->bdev; 1681da177e4SLinus Torvalds 1691da177e4SLinus Torvalds down_write(&_origins_lock); 1701da177e4SLinus Torvalds o = __lookup_origin(bdev); 1711da177e4SLinus Torvalds 1721da177e4SLinus Torvalds if (!o) { 1731da177e4SLinus Torvalds /* New origin */ 1741da177e4SLinus Torvalds o = kmalloc(sizeof(*o), GFP_KERNEL); 1751da177e4SLinus Torvalds if (!o) { 1761da177e4SLinus Torvalds up_write(&_origins_lock); 1771da177e4SLinus Torvalds return -ENOMEM; 1781da177e4SLinus Torvalds } 1791da177e4SLinus Torvalds 1801da177e4SLinus Torvalds /* Initialise the struct */ 1811da177e4SLinus Torvalds INIT_LIST_HEAD(&o->snapshots); 1821da177e4SLinus Torvalds o->bdev = bdev; 1831da177e4SLinus Torvalds 1841da177e4SLinus Torvalds __insert_origin(o); 1851da177e4SLinus Torvalds } 1861da177e4SLinus Torvalds 1871da177e4SLinus Torvalds list_add_tail(&snap->list, &o->snapshots); 1881da177e4SLinus Torvalds 1891da177e4SLinus Torvalds up_write(&_origins_lock); 1901da177e4SLinus Torvalds return 0; 1911da177e4SLinus Torvalds } 1921da177e4SLinus Torvalds 1931da177e4SLinus Torvalds static void unregister_snapshot(struct dm_snapshot *s) 1941da177e4SLinus Torvalds { 1951da177e4SLinus Torvalds struct origin *o; 1961da177e4SLinus Torvalds 1971da177e4SLinus Torvalds down_write(&_origins_lock); 1981da177e4SLinus Torvalds o = __lookup_origin(s->origin->bdev); 1991da177e4SLinus Torvalds 2001da177e4SLinus Torvalds list_del(&s->list); 2011da177e4SLinus Torvalds if (list_empty(&o->snapshots)) { 2021da177e4SLinus Torvalds list_del(&o->hash_list); 2031da177e4SLinus Torvalds kfree(o); 2041da177e4SLinus Torvalds } 2051da177e4SLinus Torvalds 2061da177e4SLinus Torvalds up_write(&_origins_lock); 2071da177e4SLinus Torvalds } 2081da177e4SLinus Torvalds 2091da177e4SLinus Torvalds /* 2101da177e4SLinus Torvalds * Implementation of the exception hash tables. 2111da177e4SLinus Torvalds */ 2121da177e4SLinus Torvalds static int init_exception_table(struct exception_table *et, uint32_t size) 2131da177e4SLinus Torvalds { 2141da177e4SLinus Torvalds unsigned int i; 2151da177e4SLinus Torvalds 2161da177e4SLinus Torvalds et->hash_mask = size - 1; 2171da177e4SLinus Torvalds et->table = dm_vcalloc(size, sizeof(struct list_head)); 2181da177e4SLinus Torvalds if (!et->table) 2191da177e4SLinus Torvalds return -ENOMEM; 2201da177e4SLinus Torvalds 2211da177e4SLinus Torvalds for (i = 0; i < size; i++) 2221da177e4SLinus Torvalds INIT_LIST_HEAD(et->table + i); 2231da177e4SLinus Torvalds 2241da177e4SLinus Torvalds return 0; 2251da177e4SLinus Torvalds } 2261da177e4SLinus Torvalds 2271da177e4SLinus Torvalds static void exit_exception_table(struct exception_table *et, kmem_cache_t *mem) 2281da177e4SLinus Torvalds { 2291da177e4SLinus Torvalds struct list_head *slot; 2301da177e4SLinus Torvalds struct exception *ex, *next; 2311da177e4SLinus Torvalds int i, size; 2321da177e4SLinus Torvalds 2331da177e4SLinus Torvalds size = et->hash_mask + 1; 2341da177e4SLinus Torvalds for (i = 0; i < size; i++) { 2351da177e4SLinus Torvalds slot = et->table + i; 2361da177e4SLinus Torvalds 2371da177e4SLinus Torvalds list_for_each_entry_safe (ex, next, slot, hash_list) 2381da177e4SLinus Torvalds kmem_cache_free(mem, ex); 2391da177e4SLinus Torvalds } 2401da177e4SLinus Torvalds 2411da177e4SLinus Torvalds vfree(et->table); 2421da177e4SLinus Torvalds } 2431da177e4SLinus Torvalds 2441da177e4SLinus Torvalds static inline uint32_t exception_hash(struct exception_table *et, chunk_t chunk) 2451da177e4SLinus Torvalds { 2461da177e4SLinus Torvalds return chunk & et->hash_mask; 2471da177e4SLinus Torvalds } 2481da177e4SLinus Torvalds 2491da177e4SLinus Torvalds static void insert_exception(struct exception_table *eh, struct exception *e) 2501da177e4SLinus Torvalds { 2511da177e4SLinus Torvalds struct list_head *l = &eh->table[exception_hash(eh, e->old_chunk)]; 2521da177e4SLinus Torvalds list_add(&e->hash_list, l); 2531da177e4SLinus Torvalds } 2541da177e4SLinus Torvalds 2551da177e4SLinus Torvalds static inline void remove_exception(struct exception *e) 2561da177e4SLinus Torvalds { 2571da177e4SLinus Torvalds list_del(&e->hash_list); 2581da177e4SLinus Torvalds } 2591da177e4SLinus Torvalds 2601da177e4SLinus Torvalds /* 2611da177e4SLinus Torvalds * Return the exception data for a sector, or NULL if not 2621da177e4SLinus Torvalds * remapped. 2631da177e4SLinus Torvalds */ 2641da177e4SLinus Torvalds static struct exception *lookup_exception(struct exception_table *et, 2651da177e4SLinus Torvalds chunk_t chunk) 2661da177e4SLinus Torvalds { 2671da177e4SLinus Torvalds struct list_head *slot; 2681da177e4SLinus Torvalds struct exception *e; 2691da177e4SLinus Torvalds 2701da177e4SLinus Torvalds slot = &et->table[exception_hash(et, chunk)]; 2711da177e4SLinus Torvalds list_for_each_entry (e, slot, hash_list) 2721da177e4SLinus Torvalds if (e->old_chunk == chunk) 2731da177e4SLinus Torvalds return e; 2741da177e4SLinus Torvalds 2751da177e4SLinus Torvalds return NULL; 2761da177e4SLinus Torvalds } 2771da177e4SLinus Torvalds 2781da177e4SLinus Torvalds static inline struct exception *alloc_exception(void) 2791da177e4SLinus Torvalds { 2801da177e4SLinus Torvalds struct exception *e; 2811da177e4SLinus Torvalds 2821da177e4SLinus Torvalds e = kmem_cache_alloc(exception_cache, GFP_NOIO); 2831da177e4SLinus Torvalds if (!e) 2841da177e4SLinus Torvalds e = kmem_cache_alloc(exception_cache, GFP_ATOMIC); 2851da177e4SLinus Torvalds 2861da177e4SLinus Torvalds return e; 2871da177e4SLinus Torvalds } 2881da177e4SLinus Torvalds 2891da177e4SLinus Torvalds static inline void free_exception(struct exception *e) 2901da177e4SLinus Torvalds { 2911da177e4SLinus Torvalds kmem_cache_free(exception_cache, e); 2921da177e4SLinus Torvalds } 2931da177e4SLinus Torvalds 2941da177e4SLinus Torvalds static inline struct pending_exception *alloc_pending_exception(void) 2951da177e4SLinus Torvalds { 2961da177e4SLinus Torvalds return mempool_alloc(pending_pool, GFP_NOIO); 2971da177e4SLinus Torvalds } 2981da177e4SLinus Torvalds 2991da177e4SLinus Torvalds static inline void free_pending_exception(struct pending_exception *pe) 3001da177e4SLinus Torvalds { 3011da177e4SLinus Torvalds mempool_free(pe, pending_pool); 3021da177e4SLinus Torvalds } 3031da177e4SLinus Torvalds 3041da177e4SLinus Torvalds int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new) 3051da177e4SLinus Torvalds { 3061da177e4SLinus Torvalds struct exception *e; 3071da177e4SLinus Torvalds 3081da177e4SLinus Torvalds e = alloc_exception(); 3091da177e4SLinus Torvalds if (!e) 3101da177e4SLinus Torvalds return -ENOMEM; 3111da177e4SLinus Torvalds 3121da177e4SLinus Torvalds e->old_chunk = old; 3131da177e4SLinus Torvalds e->new_chunk = new; 3141da177e4SLinus Torvalds insert_exception(&s->complete, e); 3151da177e4SLinus Torvalds return 0; 3161da177e4SLinus Torvalds } 3171da177e4SLinus Torvalds 3181da177e4SLinus Torvalds /* 3191da177e4SLinus Torvalds * Hard coded magic. 3201da177e4SLinus Torvalds */ 3211da177e4SLinus Torvalds static int calc_max_buckets(void) 3221da177e4SLinus Torvalds { 3231da177e4SLinus Torvalds /* use a fixed size of 2MB */ 3241da177e4SLinus Torvalds unsigned long mem = 2 * 1024 * 1024; 3251da177e4SLinus Torvalds mem /= sizeof(struct list_head); 3261da177e4SLinus Torvalds 3271da177e4SLinus Torvalds return mem; 3281da177e4SLinus Torvalds } 3291da177e4SLinus Torvalds 3301da177e4SLinus Torvalds /* 3311da177e4SLinus Torvalds * Rounds a number down to a power of 2. 3321da177e4SLinus Torvalds */ 3331da177e4SLinus Torvalds static inline uint32_t round_down(uint32_t n) 3341da177e4SLinus Torvalds { 3351da177e4SLinus Torvalds while (n & (n - 1)) 3361da177e4SLinus Torvalds n &= (n - 1); 3371da177e4SLinus Torvalds return n; 3381da177e4SLinus Torvalds } 3391da177e4SLinus Torvalds 3401da177e4SLinus Torvalds /* 3411da177e4SLinus Torvalds * Allocate room for a suitable hash table. 3421da177e4SLinus Torvalds */ 3431da177e4SLinus Torvalds static int init_hash_tables(struct dm_snapshot *s) 3441da177e4SLinus Torvalds { 3451da177e4SLinus Torvalds sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets; 3461da177e4SLinus Torvalds 3471da177e4SLinus Torvalds /* 3481da177e4SLinus Torvalds * Calculate based on the size of the original volume or 3491da177e4SLinus Torvalds * the COW volume... 3501da177e4SLinus Torvalds */ 3511da177e4SLinus Torvalds cow_dev_size = get_dev_size(s->cow->bdev); 3521da177e4SLinus Torvalds origin_dev_size = get_dev_size(s->origin->bdev); 3531da177e4SLinus Torvalds max_buckets = calc_max_buckets(); 3541da177e4SLinus Torvalds 3551da177e4SLinus Torvalds hash_size = min(origin_dev_size, cow_dev_size) >> s->chunk_shift; 3561da177e4SLinus Torvalds hash_size = min(hash_size, max_buckets); 3571da177e4SLinus Torvalds 3581da177e4SLinus Torvalds /* Round it down to a power of 2 */ 3591da177e4SLinus Torvalds hash_size = round_down(hash_size); 3601da177e4SLinus Torvalds if (init_exception_table(&s->complete, hash_size)) 3611da177e4SLinus Torvalds return -ENOMEM; 3621da177e4SLinus Torvalds 3631da177e4SLinus Torvalds /* 3641da177e4SLinus Torvalds * Allocate hash table for in-flight exceptions 3651da177e4SLinus Torvalds * Make this smaller than the real hash table 3661da177e4SLinus Torvalds */ 3671da177e4SLinus Torvalds hash_size >>= 3; 3681da177e4SLinus Torvalds if (hash_size < 64) 3691da177e4SLinus Torvalds hash_size = 64; 3701da177e4SLinus Torvalds 3711da177e4SLinus Torvalds if (init_exception_table(&s->pending, hash_size)) { 3721da177e4SLinus Torvalds exit_exception_table(&s->complete, exception_cache); 3731da177e4SLinus Torvalds return -ENOMEM; 3741da177e4SLinus Torvalds } 3751da177e4SLinus Torvalds 3761da177e4SLinus Torvalds return 0; 3771da177e4SLinus Torvalds } 3781da177e4SLinus Torvalds 3791da177e4SLinus Torvalds /* 3801da177e4SLinus Torvalds * Round a number up to the nearest 'size' boundary. size must 3811da177e4SLinus Torvalds * be a power of 2. 3821da177e4SLinus Torvalds */ 3831da177e4SLinus Torvalds static inline ulong round_up(ulong n, ulong size) 3841da177e4SLinus Torvalds { 3851da177e4SLinus Torvalds size--; 3861da177e4SLinus Torvalds return (n + size) & ~size; 3871da177e4SLinus Torvalds } 3881da177e4SLinus Torvalds 3892d38fe20SAlasdair G Kergon static void read_snapshot_metadata(struct dm_snapshot *s) 3902d38fe20SAlasdair G Kergon { 3912d38fe20SAlasdair G Kergon if (s->store.read_metadata(&s->store)) { 3922d38fe20SAlasdair G Kergon down_write(&s->lock); 3932d38fe20SAlasdair G Kergon s->valid = 0; 3942d38fe20SAlasdair G Kergon up_write(&s->lock); 3952d38fe20SAlasdair G Kergon } 3962d38fe20SAlasdair G Kergon } 3972d38fe20SAlasdair G Kergon 3981da177e4SLinus Torvalds /* 3991da177e4SLinus Torvalds * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size> 4001da177e4SLinus Torvalds */ 4011da177e4SLinus Torvalds static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) 4021da177e4SLinus Torvalds { 4031da177e4SLinus Torvalds struct dm_snapshot *s; 4041da177e4SLinus Torvalds unsigned long chunk_size; 4051da177e4SLinus Torvalds int r = -EINVAL; 4061da177e4SLinus Torvalds char persistent; 4071da177e4SLinus Torvalds char *origin_path; 4081da177e4SLinus Torvalds char *cow_path; 4091da177e4SLinus Torvalds char *value; 4101da177e4SLinus Torvalds int blocksize; 4111da177e4SLinus Torvalds 4121da177e4SLinus Torvalds if (argc < 4) { 4131da177e4SLinus Torvalds ti->error = "dm-snapshot: requires exactly 4 arguments"; 4141da177e4SLinus Torvalds r = -EINVAL; 4151da177e4SLinus Torvalds goto bad1; 4161da177e4SLinus Torvalds } 4171da177e4SLinus Torvalds 4181da177e4SLinus Torvalds origin_path = argv[0]; 4191da177e4SLinus Torvalds cow_path = argv[1]; 4201da177e4SLinus Torvalds persistent = toupper(*argv[2]); 4211da177e4SLinus Torvalds 4221da177e4SLinus Torvalds if (persistent != 'P' && persistent != 'N') { 4231da177e4SLinus Torvalds ti->error = "Persistent flag is not P or N"; 4241da177e4SLinus Torvalds r = -EINVAL; 4251da177e4SLinus Torvalds goto bad1; 4261da177e4SLinus Torvalds } 4271da177e4SLinus Torvalds 4281da177e4SLinus Torvalds chunk_size = simple_strtoul(argv[3], &value, 10); 4291da177e4SLinus Torvalds if (chunk_size == 0 || value == NULL) { 4301da177e4SLinus Torvalds ti->error = "Invalid chunk size"; 4311da177e4SLinus Torvalds r = -EINVAL; 4321da177e4SLinus Torvalds goto bad1; 4331da177e4SLinus Torvalds } 4341da177e4SLinus Torvalds 4351da177e4SLinus Torvalds s = kmalloc(sizeof(*s), GFP_KERNEL); 4361da177e4SLinus Torvalds if (s == NULL) { 4371da177e4SLinus Torvalds ti->error = "Cannot allocate snapshot context private " 4381da177e4SLinus Torvalds "structure"; 4391da177e4SLinus Torvalds r = -ENOMEM; 4401da177e4SLinus Torvalds goto bad1; 4411da177e4SLinus Torvalds } 4421da177e4SLinus Torvalds 4431da177e4SLinus Torvalds r = dm_get_device(ti, origin_path, 0, ti->len, FMODE_READ, &s->origin); 4441da177e4SLinus Torvalds if (r) { 4451da177e4SLinus Torvalds ti->error = "Cannot get origin device"; 4461da177e4SLinus Torvalds goto bad2; 4471da177e4SLinus Torvalds } 4481da177e4SLinus Torvalds 4491da177e4SLinus Torvalds r = dm_get_device(ti, cow_path, 0, 0, 4501da177e4SLinus Torvalds FMODE_READ | FMODE_WRITE, &s->cow); 4511da177e4SLinus Torvalds if (r) { 4521da177e4SLinus Torvalds dm_put_device(ti, s->origin); 4531da177e4SLinus Torvalds ti->error = "Cannot get COW device"; 4541da177e4SLinus Torvalds goto bad2; 4551da177e4SLinus Torvalds } 4561da177e4SLinus Torvalds 4571da177e4SLinus Torvalds /* 4581da177e4SLinus Torvalds * Chunk size must be multiple of page size. Silently 4591da177e4SLinus Torvalds * round up if it's not. 4601da177e4SLinus Torvalds */ 4611da177e4SLinus Torvalds chunk_size = round_up(chunk_size, PAGE_SIZE >> 9); 4621da177e4SLinus Torvalds 4631da177e4SLinus Torvalds /* Validate the chunk size against the device block size */ 4641da177e4SLinus Torvalds blocksize = s->cow->bdev->bd_disk->queue->hardsect_size; 4651da177e4SLinus Torvalds if (chunk_size % (blocksize >> 9)) { 4661da177e4SLinus Torvalds ti->error = "Chunk size is not a multiple of device blocksize"; 4671da177e4SLinus Torvalds r = -EINVAL; 4681da177e4SLinus Torvalds goto bad3; 4691da177e4SLinus Torvalds } 4701da177e4SLinus Torvalds 4711da177e4SLinus Torvalds /* Check chunk_size is a power of 2 */ 4721da177e4SLinus Torvalds if (chunk_size & (chunk_size - 1)) { 4731da177e4SLinus Torvalds ti->error = "Chunk size is not a power of 2"; 4741da177e4SLinus Torvalds r = -EINVAL; 4751da177e4SLinus Torvalds goto bad3; 4761da177e4SLinus Torvalds } 4771da177e4SLinus Torvalds 4781da177e4SLinus Torvalds s->chunk_size = chunk_size; 4791da177e4SLinus Torvalds s->chunk_mask = chunk_size - 1; 4801da177e4SLinus Torvalds s->type = persistent; 4811da177e4SLinus Torvalds s->chunk_shift = ffs(chunk_size) - 1; 4821da177e4SLinus Torvalds 4831da177e4SLinus Torvalds s->valid = 1; 484aa14edebSAlasdair G Kergon s->active = 0; 4851da177e4SLinus Torvalds s->last_percent = 0; 4861da177e4SLinus Torvalds init_rwsem(&s->lock); 4871da177e4SLinus Torvalds s->table = ti->table; 4881da177e4SLinus Torvalds 4891da177e4SLinus Torvalds /* Allocate hash table for COW data */ 4901da177e4SLinus Torvalds if (init_hash_tables(s)) { 4911da177e4SLinus Torvalds ti->error = "Unable to allocate hash table space"; 4921da177e4SLinus Torvalds r = -ENOMEM; 4931da177e4SLinus Torvalds goto bad3; 4941da177e4SLinus Torvalds } 4951da177e4SLinus Torvalds 4961da177e4SLinus Torvalds /* 4971da177e4SLinus Torvalds * Check the persistent flag - done here because we need the iobuf 4981da177e4SLinus Torvalds * to check the LV header 4991da177e4SLinus Torvalds */ 5001da177e4SLinus Torvalds s->store.snap = s; 5011da177e4SLinus Torvalds 5021da177e4SLinus Torvalds if (persistent == 'P') 5031da177e4SLinus Torvalds r = dm_create_persistent(&s->store, chunk_size); 5041da177e4SLinus Torvalds else 5051da177e4SLinus Torvalds r = dm_create_transient(&s->store, s, blocksize); 5061da177e4SLinus Torvalds 5071da177e4SLinus Torvalds if (r) { 5081da177e4SLinus Torvalds ti->error = "Couldn't create exception store"; 5091da177e4SLinus Torvalds r = -EINVAL; 5101da177e4SLinus Torvalds goto bad4; 5111da177e4SLinus Torvalds } 5121da177e4SLinus Torvalds 5131da177e4SLinus Torvalds r = kcopyd_client_create(SNAPSHOT_PAGES, &s->kcopyd_client); 5141da177e4SLinus Torvalds if (r) { 5151da177e4SLinus Torvalds ti->error = "Could not create kcopyd client"; 5161da177e4SLinus Torvalds goto bad5; 5171da177e4SLinus Torvalds } 5181da177e4SLinus Torvalds 519aa14edebSAlasdair G Kergon /* Metadata must only be loaded into one table at once */ 520aa14edebSAlasdair G Kergon read_snapshot_metadata(s); 521aa14edebSAlasdair G Kergon 5221da177e4SLinus Torvalds /* Add snapshot to the list of snapshots for this origin */ 523aa14edebSAlasdair G Kergon /* Exceptions aren't triggered till snapshot_resume() is called */ 5241da177e4SLinus Torvalds if (register_snapshot(s)) { 5251da177e4SLinus Torvalds r = -EINVAL; 5261da177e4SLinus Torvalds ti->error = "Cannot register snapshot origin"; 5271da177e4SLinus Torvalds goto bad6; 5281da177e4SLinus Torvalds } 5291da177e4SLinus Torvalds 5301da177e4SLinus Torvalds ti->private = s; 5311da177e4SLinus Torvalds ti->split_io = chunk_size; 5321da177e4SLinus Torvalds 5331da177e4SLinus Torvalds return 0; 5341da177e4SLinus Torvalds 5351da177e4SLinus Torvalds bad6: 5361da177e4SLinus Torvalds kcopyd_client_destroy(s->kcopyd_client); 5371da177e4SLinus Torvalds 5381da177e4SLinus Torvalds bad5: 5391da177e4SLinus Torvalds s->store.destroy(&s->store); 5401da177e4SLinus Torvalds 5411da177e4SLinus Torvalds bad4: 5421da177e4SLinus Torvalds exit_exception_table(&s->pending, pending_cache); 5431da177e4SLinus Torvalds exit_exception_table(&s->complete, exception_cache); 5441da177e4SLinus Torvalds 5451da177e4SLinus Torvalds bad3: 5461da177e4SLinus Torvalds dm_put_device(ti, s->cow); 5471da177e4SLinus Torvalds dm_put_device(ti, s->origin); 5481da177e4SLinus Torvalds 5491da177e4SLinus Torvalds bad2: 5501da177e4SLinus Torvalds kfree(s); 5511da177e4SLinus Torvalds 5521da177e4SLinus Torvalds bad1: 5531da177e4SLinus Torvalds return r; 5541da177e4SLinus Torvalds } 5551da177e4SLinus Torvalds 5561da177e4SLinus Torvalds static void snapshot_dtr(struct dm_target *ti) 5571da177e4SLinus Torvalds { 5581da177e4SLinus Torvalds struct dm_snapshot *s = (struct dm_snapshot *) ti->private; 5591da177e4SLinus Torvalds 5601da177e4SLinus Torvalds unregister_snapshot(s); 5611da177e4SLinus Torvalds 5621da177e4SLinus Torvalds exit_exception_table(&s->pending, pending_cache); 5631da177e4SLinus Torvalds exit_exception_table(&s->complete, exception_cache); 5641da177e4SLinus Torvalds 5651da177e4SLinus Torvalds /* Deallocate memory used */ 5661da177e4SLinus Torvalds s->store.destroy(&s->store); 5671da177e4SLinus Torvalds 5681da177e4SLinus Torvalds dm_put_device(ti, s->origin); 5691da177e4SLinus Torvalds dm_put_device(ti, s->cow); 5701da177e4SLinus Torvalds kcopyd_client_destroy(s->kcopyd_client); 5711da177e4SLinus Torvalds kfree(s); 5721da177e4SLinus Torvalds } 5731da177e4SLinus Torvalds 5741da177e4SLinus Torvalds /* 5751da177e4SLinus Torvalds * Flush a list of buffers. 5761da177e4SLinus Torvalds */ 5771da177e4SLinus Torvalds static void flush_bios(struct bio *bio) 5781da177e4SLinus Torvalds { 5791da177e4SLinus Torvalds struct bio *n; 5801da177e4SLinus Torvalds 5811da177e4SLinus Torvalds while (bio) { 5821da177e4SLinus Torvalds n = bio->bi_next; 5831da177e4SLinus Torvalds bio->bi_next = NULL; 5841da177e4SLinus Torvalds generic_make_request(bio); 5851da177e4SLinus Torvalds bio = n; 5861da177e4SLinus Torvalds } 5871da177e4SLinus Torvalds } 5881da177e4SLinus Torvalds 5891da177e4SLinus Torvalds /* 5901da177e4SLinus Torvalds * Error a list of buffers. 5911da177e4SLinus Torvalds */ 5921da177e4SLinus Torvalds static void error_bios(struct bio *bio) 5931da177e4SLinus Torvalds { 5941da177e4SLinus Torvalds struct bio *n; 5951da177e4SLinus Torvalds 5961da177e4SLinus Torvalds while (bio) { 5971da177e4SLinus Torvalds n = bio->bi_next; 5981da177e4SLinus Torvalds bio->bi_next = NULL; 5991da177e4SLinus Torvalds bio_io_error(bio, bio->bi_size); 6001da177e4SLinus Torvalds bio = n; 6011da177e4SLinus Torvalds } 6021da177e4SLinus Torvalds } 6031da177e4SLinus Torvalds 6041da177e4SLinus Torvalds static struct bio *__flush_bios(struct pending_exception *pe) 6051da177e4SLinus Torvalds { 606b4b610f6SAlasdair G Kergon /* 607b4b610f6SAlasdair G Kergon * If this pe is involved in a write to the origin and 608b4b610f6SAlasdair G Kergon * it is the last sibling to complete then release 609b4b610f6SAlasdair G Kergon * the bios for the original write to the origin. 6101da177e4SLinus Torvalds */ 611b4b610f6SAlasdair G Kergon 612b4b610f6SAlasdair G Kergon if (pe->primary_pe && 613b4b610f6SAlasdair G Kergon atomic_dec_and_test(&pe->primary_pe->sibling_count)) 614b4b610f6SAlasdair G Kergon return bio_list_get(&pe->primary_pe->origin_bios); 6151da177e4SLinus Torvalds 6161da177e4SLinus Torvalds return NULL; 6171da177e4SLinus Torvalds } 6181da177e4SLinus Torvalds 6191da177e4SLinus Torvalds static void pending_complete(struct pending_exception *pe, int success) 6201da177e4SLinus Torvalds { 6211da177e4SLinus Torvalds struct exception *e; 622b4b610f6SAlasdair G Kergon struct pending_exception *primary_pe; 6231da177e4SLinus Torvalds struct dm_snapshot *s = pe->snap; 6241da177e4SLinus Torvalds struct bio *flush = NULL; 6251da177e4SLinus Torvalds 6261da177e4SLinus Torvalds if (success) { 6271da177e4SLinus Torvalds e = alloc_exception(); 6281da177e4SLinus Torvalds if (!e) { 6291da177e4SLinus Torvalds DMWARN("Unable to allocate exception."); 6301da177e4SLinus Torvalds down_write(&s->lock); 6311da177e4SLinus Torvalds s->store.drop_snapshot(&s->store); 6321da177e4SLinus Torvalds s->valid = 0; 6331da177e4SLinus Torvalds flush = __flush_bios(pe); 6341da177e4SLinus Torvalds up_write(&s->lock); 6351da177e4SLinus Torvalds 6361da177e4SLinus Torvalds error_bios(bio_list_get(&pe->snapshot_bios)); 6371da177e4SLinus Torvalds goto out; 6381da177e4SLinus Torvalds } 6391da177e4SLinus Torvalds *e = pe->e; 6401da177e4SLinus Torvalds 6411da177e4SLinus Torvalds /* 6421da177e4SLinus Torvalds * Add a proper exception, and remove the 6431da177e4SLinus Torvalds * in-flight exception from the list. 6441da177e4SLinus Torvalds */ 6451da177e4SLinus Torvalds down_write(&s->lock); 6461da177e4SLinus Torvalds insert_exception(&s->complete, e); 6471da177e4SLinus Torvalds remove_exception(&pe->e); 6481da177e4SLinus Torvalds flush = __flush_bios(pe); 6491da177e4SLinus Torvalds 6501da177e4SLinus Torvalds /* Submit any pending write bios */ 6511da177e4SLinus Torvalds up_write(&s->lock); 6521da177e4SLinus Torvalds 6531da177e4SLinus Torvalds flush_bios(bio_list_get(&pe->snapshot_bios)); 6541da177e4SLinus Torvalds } else { 6551da177e4SLinus Torvalds /* Read/write error - snapshot is unusable */ 6561da177e4SLinus Torvalds down_write(&s->lock); 6571da177e4SLinus Torvalds if (s->valid) 6581da177e4SLinus Torvalds DMERR("Error reading/writing snapshot"); 6591da177e4SLinus Torvalds s->store.drop_snapshot(&s->store); 6601da177e4SLinus Torvalds s->valid = 0; 6611da177e4SLinus Torvalds remove_exception(&pe->e); 6621da177e4SLinus Torvalds flush = __flush_bios(pe); 6631da177e4SLinus Torvalds up_write(&s->lock); 6641da177e4SLinus Torvalds 6651da177e4SLinus Torvalds error_bios(bio_list_get(&pe->snapshot_bios)); 6661da177e4SLinus Torvalds 6671da177e4SLinus Torvalds dm_table_event(s->table); 6681da177e4SLinus Torvalds } 6691da177e4SLinus Torvalds 6701da177e4SLinus Torvalds out: 671b4b610f6SAlasdair G Kergon primary_pe = pe->primary_pe; 672b4b610f6SAlasdair G Kergon 673b4b610f6SAlasdair G Kergon /* 674b4b610f6SAlasdair G Kergon * Free the pe if it's not linked to an origin write or if 675b4b610f6SAlasdair G Kergon * it's not itself a primary pe. 676b4b610f6SAlasdair G Kergon */ 677b4b610f6SAlasdair G Kergon if (!primary_pe || primary_pe != pe) 6781da177e4SLinus Torvalds free_pending_exception(pe); 6791da177e4SLinus Torvalds 680b4b610f6SAlasdair G Kergon /* 681b4b610f6SAlasdair G Kergon * Free the primary pe if nothing references it. 682b4b610f6SAlasdair G Kergon */ 683b4b610f6SAlasdair G Kergon if (primary_pe && !atomic_read(&primary_pe->sibling_count)) 684b4b610f6SAlasdair G Kergon free_pending_exception(primary_pe); 685b4b610f6SAlasdair G Kergon 6861da177e4SLinus Torvalds if (flush) 6871da177e4SLinus Torvalds flush_bios(flush); 6881da177e4SLinus Torvalds } 6891da177e4SLinus Torvalds 6901da177e4SLinus Torvalds static void commit_callback(void *context, int success) 6911da177e4SLinus Torvalds { 6921da177e4SLinus Torvalds struct pending_exception *pe = (struct pending_exception *) context; 6931da177e4SLinus Torvalds pending_complete(pe, success); 6941da177e4SLinus Torvalds } 6951da177e4SLinus Torvalds 6961da177e4SLinus Torvalds /* 6971da177e4SLinus Torvalds * Called when the copy I/O has finished. kcopyd actually runs 6981da177e4SLinus Torvalds * this code so don't block. 6991da177e4SLinus Torvalds */ 7001da177e4SLinus Torvalds static void copy_callback(int read_err, unsigned int write_err, void *context) 7011da177e4SLinus Torvalds { 7021da177e4SLinus Torvalds struct pending_exception *pe = (struct pending_exception *) context; 7031da177e4SLinus Torvalds struct dm_snapshot *s = pe->snap; 7041da177e4SLinus Torvalds 7051da177e4SLinus Torvalds if (read_err || write_err) 7061da177e4SLinus Torvalds pending_complete(pe, 0); 7071da177e4SLinus Torvalds 7081da177e4SLinus Torvalds else 7091da177e4SLinus Torvalds /* Update the metadata if we are persistent */ 7101da177e4SLinus Torvalds s->store.commit_exception(&s->store, &pe->e, commit_callback, 7111da177e4SLinus Torvalds pe); 7121da177e4SLinus Torvalds } 7131da177e4SLinus Torvalds 7141da177e4SLinus Torvalds /* 7151da177e4SLinus Torvalds * Dispatches the copy operation to kcopyd. 7161da177e4SLinus Torvalds */ 717858119e1SArjan van de Ven static void start_copy(struct pending_exception *pe) 7181da177e4SLinus Torvalds { 7191da177e4SLinus Torvalds struct dm_snapshot *s = pe->snap; 7201da177e4SLinus Torvalds struct io_region src, dest; 7211da177e4SLinus Torvalds struct block_device *bdev = s->origin->bdev; 7221da177e4SLinus Torvalds sector_t dev_size; 7231da177e4SLinus Torvalds 7241da177e4SLinus Torvalds dev_size = get_dev_size(bdev); 7251da177e4SLinus Torvalds 7261da177e4SLinus Torvalds src.bdev = bdev; 7271da177e4SLinus Torvalds src.sector = chunk_to_sector(s, pe->e.old_chunk); 7281da177e4SLinus Torvalds src.count = min(s->chunk_size, dev_size - src.sector); 7291da177e4SLinus Torvalds 7301da177e4SLinus Torvalds dest.bdev = s->cow->bdev; 7311da177e4SLinus Torvalds dest.sector = chunk_to_sector(s, pe->e.new_chunk); 7321da177e4SLinus Torvalds dest.count = src.count; 7331da177e4SLinus Torvalds 7341da177e4SLinus Torvalds /* Hand over to kcopyd */ 7351da177e4SLinus Torvalds kcopyd_copy(s->kcopyd_client, 7361da177e4SLinus Torvalds &src, 1, &dest, 0, copy_callback, pe); 7371da177e4SLinus Torvalds } 7381da177e4SLinus Torvalds 7391da177e4SLinus Torvalds /* 7401da177e4SLinus Torvalds * Looks to see if this snapshot already has a pending exception 7411da177e4SLinus Torvalds * for this chunk, otherwise it allocates a new one and inserts 7421da177e4SLinus Torvalds * it into the pending table. 7431da177e4SLinus Torvalds * 7441da177e4SLinus Torvalds * NOTE: a write lock must be held on snap->lock before calling 7451da177e4SLinus Torvalds * this. 7461da177e4SLinus Torvalds */ 7471da177e4SLinus Torvalds static struct pending_exception * 7481da177e4SLinus Torvalds __find_pending_exception(struct dm_snapshot *s, struct bio *bio) 7491da177e4SLinus Torvalds { 7501da177e4SLinus Torvalds struct exception *e; 7511da177e4SLinus Torvalds struct pending_exception *pe; 7521da177e4SLinus Torvalds chunk_t chunk = sector_to_chunk(s, bio->bi_sector); 7531da177e4SLinus Torvalds 7541da177e4SLinus Torvalds /* 7551da177e4SLinus Torvalds * Is there a pending exception for this already ? 7561da177e4SLinus Torvalds */ 7571da177e4SLinus Torvalds e = lookup_exception(&s->pending, chunk); 7581da177e4SLinus Torvalds if (e) { 7591da177e4SLinus Torvalds /* cast the exception to a pending exception */ 7601da177e4SLinus Torvalds pe = container_of(e, struct pending_exception, e); 7611da177e4SLinus Torvalds 7621da177e4SLinus Torvalds } else { 7631da177e4SLinus Torvalds /* 7641da177e4SLinus Torvalds * Create a new pending exception, we don't want 7651da177e4SLinus Torvalds * to hold the lock while we do this. 7661da177e4SLinus Torvalds */ 7671da177e4SLinus Torvalds up_write(&s->lock); 7681da177e4SLinus Torvalds pe = alloc_pending_exception(); 7691da177e4SLinus Torvalds down_write(&s->lock); 7701da177e4SLinus Torvalds 7711da177e4SLinus Torvalds e = lookup_exception(&s->pending, chunk); 7721da177e4SLinus Torvalds if (e) { 7731da177e4SLinus Torvalds free_pending_exception(pe); 7741da177e4SLinus Torvalds pe = container_of(e, struct pending_exception, e); 7751da177e4SLinus Torvalds } else { 7761da177e4SLinus Torvalds pe->e.old_chunk = chunk; 7771da177e4SLinus Torvalds bio_list_init(&pe->origin_bios); 7781da177e4SLinus Torvalds bio_list_init(&pe->snapshot_bios); 779b4b610f6SAlasdair G Kergon pe->primary_pe = NULL; 780b4b610f6SAlasdair G Kergon atomic_set(&pe->sibling_count, 1); 7811da177e4SLinus Torvalds pe->snap = s; 7821da177e4SLinus Torvalds pe->started = 0; 7831da177e4SLinus Torvalds 7841da177e4SLinus Torvalds if (s->store.prepare_exception(&s->store, &pe->e)) { 7851da177e4SLinus Torvalds free_pending_exception(pe); 7861da177e4SLinus Torvalds s->valid = 0; 7871da177e4SLinus Torvalds return NULL; 7881da177e4SLinus Torvalds } 7891da177e4SLinus Torvalds 7901da177e4SLinus Torvalds insert_exception(&s->pending, &pe->e); 7911da177e4SLinus Torvalds } 7921da177e4SLinus Torvalds } 7931da177e4SLinus Torvalds 7941da177e4SLinus Torvalds return pe; 7951da177e4SLinus Torvalds } 7961da177e4SLinus Torvalds 7971da177e4SLinus Torvalds static inline void remap_exception(struct dm_snapshot *s, struct exception *e, 7981da177e4SLinus Torvalds struct bio *bio) 7991da177e4SLinus Torvalds { 8001da177e4SLinus Torvalds bio->bi_bdev = s->cow->bdev; 8011da177e4SLinus Torvalds bio->bi_sector = chunk_to_sector(s, e->new_chunk) + 8021da177e4SLinus Torvalds (bio->bi_sector & s->chunk_mask); 8031da177e4SLinus Torvalds } 8041da177e4SLinus Torvalds 8051da177e4SLinus Torvalds static int snapshot_map(struct dm_target *ti, struct bio *bio, 8061da177e4SLinus Torvalds union map_info *map_context) 8071da177e4SLinus Torvalds { 8081da177e4SLinus Torvalds struct exception *e; 8091da177e4SLinus Torvalds struct dm_snapshot *s = (struct dm_snapshot *) ti->private; 8101da177e4SLinus Torvalds int r = 1; 8111da177e4SLinus Torvalds chunk_t chunk; 8121da177e4SLinus Torvalds struct pending_exception *pe; 8131da177e4SLinus Torvalds 8141da177e4SLinus Torvalds chunk = sector_to_chunk(s, bio->bi_sector); 8151da177e4SLinus Torvalds 8161da177e4SLinus Torvalds /* Full snapshots are not usable */ 8171da177e4SLinus Torvalds if (!s->valid) 818f6a80ea8SAlasdair G Kergon return -EIO; 8191da177e4SLinus Torvalds 8204aac0a63SAlasdair G Kergon if (unlikely(bio_barrier(bio))) 8214aac0a63SAlasdair G Kergon return -EOPNOTSUPP; 8224aac0a63SAlasdair G Kergon 8231da177e4SLinus Torvalds /* 8241da177e4SLinus Torvalds * Write to snapshot - higher level takes care of RW/RO 8251da177e4SLinus Torvalds * flags so we should only get this if we are 8261da177e4SLinus Torvalds * writeable. 8271da177e4SLinus Torvalds */ 8281da177e4SLinus Torvalds if (bio_rw(bio) == WRITE) { 8291da177e4SLinus Torvalds 8301da177e4SLinus Torvalds /* FIXME: should only take write lock if we need 8311da177e4SLinus Torvalds * to copy an exception */ 8321da177e4SLinus Torvalds down_write(&s->lock); 8331da177e4SLinus Torvalds 8341da177e4SLinus Torvalds /* If the block is already remapped - use that, else remap it */ 8351da177e4SLinus Torvalds e = lookup_exception(&s->complete, chunk); 8361da177e4SLinus Torvalds if (e) { 8371da177e4SLinus Torvalds remap_exception(s, e, bio); 8381da177e4SLinus Torvalds up_write(&s->lock); 8391da177e4SLinus Torvalds 8401da177e4SLinus Torvalds } else { 8411da177e4SLinus Torvalds pe = __find_pending_exception(s, bio); 8421da177e4SLinus Torvalds 8431da177e4SLinus Torvalds if (!pe) { 8441da177e4SLinus Torvalds if (s->store.drop_snapshot) 8451da177e4SLinus Torvalds s->store.drop_snapshot(&s->store); 8461da177e4SLinus Torvalds s->valid = 0; 8471da177e4SLinus Torvalds r = -EIO; 8481da177e4SLinus Torvalds up_write(&s->lock); 8491da177e4SLinus Torvalds } else { 8501da177e4SLinus Torvalds remap_exception(s, &pe->e, bio); 8511da177e4SLinus Torvalds bio_list_add(&pe->snapshot_bios, bio); 8521da177e4SLinus Torvalds 8531da177e4SLinus Torvalds if (!pe->started) { 8541da177e4SLinus Torvalds /* this is protected by snap->lock */ 8551da177e4SLinus Torvalds pe->started = 1; 8561da177e4SLinus Torvalds up_write(&s->lock); 8571da177e4SLinus Torvalds start_copy(pe); 8581da177e4SLinus Torvalds } else 8591da177e4SLinus Torvalds up_write(&s->lock); 8601da177e4SLinus Torvalds r = 0; 8611da177e4SLinus Torvalds } 8621da177e4SLinus Torvalds } 8631da177e4SLinus Torvalds 8641da177e4SLinus Torvalds } else { 8651da177e4SLinus Torvalds /* 8661da177e4SLinus Torvalds * FIXME: this read path scares me because we 8671da177e4SLinus Torvalds * always use the origin when we have a pending 8681da177e4SLinus Torvalds * exception. However I can't think of a 8691da177e4SLinus Torvalds * situation where this is wrong - ejt. 8701da177e4SLinus Torvalds */ 8711da177e4SLinus Torvalds 8721da177e4SLinus Torvalds /* Do reads */ 8731da177e4SLinus Torvalds down_read(&s->lock); 8741da177e4SLinus Torvalds 8751da177e4SLinus Torvalds /* See if it it has been remapped */ 8761da177e4SLinus Torvalds e = lookup_exception(&s->complete, chunk); 8771da177e4SLinus Torvalds if (e) 8781da177e4SLinus Torvalds remap_exception(s, e, bio); 8791da177e4SLinus Torvalds else 8801da177e4SLinus Torvalds bio->bi_bdev = s->origin->bdev; 8811da177e4SLinus Torvalds 8821da177e4SLinus Torvalds up_read(&s->lock); 8831da177e4SLinus Torvalds } 8841da177e4SLinus Torvalds 8851da177e4SLinus Torvalds return r; 8861da177e4SLinus Torvalds } 8871da177e4SLinus Torvalds 8881da177e4SLinus Torvalds static void snapshot_resume(struct dm_target *ti) 8891da177e4SLinus Torvalds { 8901da177e4SLinus Torvalds struct dm_snapshot *s = (struct dm_snapshot *) ti->private; 8911da177e4SLinus Torvalds 892aa14edebSAlasdair G Kergon down_write(&s->lock); 893aa14edebSAlasdair G Kergon s->active = 1; 894aa14edebSAlasdair G Kergon up_write(&s->lock); 8951da177e4SLinus Torvalds } 8961da177e4SLinus Torvalds 8971da177e4SLinus Torvalds static int snapshot_status(struct dm_target *ti, status_type_t type, 8981da177e4SLinus Torvalds char *result, unsigned int maxlen) 8991da177e4SLinus Torvalds { 9001da177e4SLinus Torvalds struct dm_snapshot *snap = (struct dm_snapshot *) ti->private; 9011da177e4SLinus Torvalds 9021da177e4SLinus Torvalds switch (type) { 9031da177e4SLinus Torvalds case STATUSTYPE_INFO: 9041da177e4SLinus Torvalds if (!snap->valid) 9051da177e4SLinus Torvalds snprintf(result, maxlen, "Invalid"); 9061da177e4SLinus Torvalds else { 9071da177e4SLinus Torvalds if (snap->store.fraction_full) { 9081da177e4SLinus Torvalds sector_t numerator, denominator; 9091da177e4SLinus Torvalds snap->store.fraction_full(&snap->store, 9101da177e4SLinus Torvalds &numerator, 9111da177e4SLinus Torvalds &denominator); 9121da177e4SLinus Torvalds snprintf(result, maxlen, 9131da177e4SLinus Torvalds SECTOR_FORMAT "/" SECTOR_FORMAT, 9141da177e4SLinus Torvalds numerator, denominator); 9151da177e4SLinus Torvalds } 9161da177e4SLinus Torvalds else 9171da177e4SLinus Torvalds snprintf(result, maxlen, "Unknown"); 9181da177e4SLinus Torvalds } 9191da177e4SLinus Torvalds break; 9201da177e4SLinus Torvalds 9211da177e4SLinus Torvalds case STATUSTYPE_TABLE: 9221da177e4SLinus Torvalds /* 9231da177e4SLinus Torvalds * kdevname returns a static pointer so we need 9241da177e4SLinus Torvalds * to make private copies if the output is to 9251da177e4SLinus Torvalds * make sense. 9261da177e4SLinus Torvalds */ 9271da177e4SLinus Torvalds snprintf(result, maxlen, "%s %s %c " SECTOR_FORMAT, 9281da177e4SLinus Torvalds snap->origin->name, snap->cow->name, 9291da177e4SLinus Torvalds snap->type, snap->chunk_size); 9301da177e4SLinus Torvalds break; 9311da177e4SLinus Torvalds } 9321da177e4SLinus Torvalds 9331da177e4SLinus Torvalds return 0; 9341da177e4SLinus Torvalds } 9351da177e4SLinus Torvalds 9361da177e4SLinus Torvalds /*----------------------------------------------------------------- 9371da177e4SLinus Torvalds * Origin methods 9381da177e4SLinus Torvalds *---------------------------------------------------------------*/ 9391da177e4SLinus Torvalds static int __origin_write(struct list_head *snapshots, struct bio *bio) 9401da177e4SLinus Torvalds { 941b4b610f6SAlasdair G Kergon int r = 1, first = 0; 9421da177e4SLinus Torvalds struct dm_snapshot *snap; 9431da177e4SLinus Torvalds struct exception *e; 944b4b610f6SAlasdair G Kergon struct pending_exception *pe, *next_pe, *primary_pe = NULL; 9451da177e4SLinus Torvalds chunk_t chunk; 946eccf0817SAlasdair G Kergon LIST_HEAD(pe_queue); 9471da177e4SLinus Torvalds 9481da177e4SLinus Torvalds /* Do all the snapshots on this origin */ 9491da177e4SLinus Torvalds list_for_each_entry (snap, snapshots, list) { 9501da177e4SLinus Torvalds 951aa14edebSAlasdair G Kergon /* Only deal with valid and active snapshots */ 952aa14edebSAlasdair G Kergon if (!snap->valid || !snap->active) 9531da177e4SLinus Torvalds continue; 9541da177e4SLinus Torvalds 955d5e404c1SAlasdair G Kergon /* Nothing to do if writing beyond end of snapshot */ 956d5e404c1SAlasdair G Kergon if (bio->bi_sector >= dm_table_get_size(snap->table)) 957d5e404c1SAlasdair G Kergon continue; 958d5e404c1SAlasdair G Kergon 9591da177e4SLinus Torvalds down_write(&snap->lock); 9601da177e4SLinus Torvalds 9611da177e4SLinus Torvalds /* 9621da177e4SLinus Torvalds * Remember, different snapshots can have 9631da177e4SLinus Torvalds * different chunk sizes. 9641da177e4SLinus Torvalds */ 9651da177e4SLinus Torvalds chunk = sector_to_chunk(snap, bio->bi_sector); 9661da177e4SLinus Torvalds 9671da177e4SLinus Torvalds /* 9681da177e4SLinus Torvalds * Check exception table to see if block 9691da177e4SLinus Torvalds * is already remapped in this snapshot 9701da177e4SLinus Torvalds * and trigger an exception if not. 971b4b610f6SAlasdair G Kergon * 972b4b610f6SAlasdair G Kergon * sibling_count is initialised to 1 so pending_complete() 973b4b610f6SAlasdair G Kergon * won't destroy the primary_pe while we're inside this loop. 9741da177e4SLinus Torvalds */ 9751da177e4SLinus Torvalds e = lookup_exception(&snap->complete, chunk); 9761da177e4SLinus Torvalds if (!e) { 9771da177e4SLinus Torvalds pe = __find_pending_exception(snap, bio); 9781da177e4SLinus Torvalds if (!pe) { 9791da177e4SLinus Torvalds snap->store.drop_snapshot(&snap->store); 9801da177e4SLinus Torvalds snap->valid = 0; 9811da177e4SLinus Torvalds 9821da177e4SLinus Torvalds } else { 983b4b610f6SAlasdair G Kergon if (!primary_pe) { 984b4b610f6SAlasdair G Kergon /* 985b4b610f6SAlasdair G Kergon * Either every pe here has same 986b4b610f6SAlasdair G Kergon * primary_pe or none has one yet. 987b4b610f6SAlasdair G Kergon */ 988b4b610f6SAlasdair G Kergon if (pe->primary_pe) 989b4b610f6SAlasdair G Kergon primary_pe = pe->primary_pe; 990b4b610f6SAlasdair G Kergon else { 991b4b610f6SAlasdair G Kergon primary_pe = pe; 992b4b610f6SAlasdair G Kergon first = 1; 993eccf0817SAlasdair G Kergon } 994b4b610f6SAlasdair G Kergon 995b4b610f6SAlasdair G Kergon bio_list_add(&primary_pe->origin_bios, 996b4b610f6SAlasdair G Kergon bio); 997b4b610f6SAlasdair G Kergon r = 0; 998b4b610f6SAlasdair G Kergon } 999b4b610f6SAlasdair G Kergon if (!pe->primary_pe) { 1000b4b610f6SAlasdair G Kergon atomic_inc(&primary_pe->sibling_count); 1001b4b610f6SAlasdair G Kergon pe->primary_pe = primary_pe; 1002b4b610f6SAlasdair G Kergon } 1003eccf0817SAlasdair G Kergon if (!pe->started) { 1004eccf0817SAlasdair G Kergon pe->started = 1; 1005eccf0817SAlasdair G Kergon list_add_tail(&pe->list, &pe_queue); 1006eccf0817SAlasdair G Kergon } 10071da177e4SLinus Torvalds } 10081da177e4SLinus Torvalds } 10091da177e4SLinus Torvalds 10101da177e4SLinus Torvalds up_write(&snap->lock); 10111da177e4SLinus Torvalds } 10121da177e4SLinus Torvalds 1013b4b610f6SAlasdair G Kergon if (!primary_pe) 1014b4b610f6SAlasdair G Kergon goto out; 1015b4b610f6SAlasdair G Kergon 1016b4b610f6SAlasdair G Kergon /* 1017b4b610f6SAlasdair G Kergon * If this is the first time we're processing this chunk and 1018b4b610f6SAlasdair G Kergon * sibling_count is now 1 it means all the pending exceptions 1019b4b610f6SAlasdair G Kergon * got completed while we were in the loop above, so it falls to 1020b4b610f6SAlasdair G Kergon * us here to remove the primary_pe and submit any origin_bios. 1021b4b610f6SAlasdair G Kergon */ 1022b4b610f6SAlasdair G Kergon 1023b4b610f6SAlasdair G Kergon if (first && atomic_dec_and_test(&primary_pe->sibling_count)) { 1024b4b610f6SAlasdair G Kergon flush_bios(bio_list_get(&primary_pe->origin_bios)); 1025b4b610f6SAlasdair G Kergon free_pending_exception(primary_pe); 1026b4b610f6SAlasdair G Kergon /* If we got here, pe_queue is necessarily empty. */ 1027b4b610f6SAlasdair G Kergon goto out; 1028b4b610f6SAlasdair G Kergon } 1029b4b610f6SAlasdair G Kergon 10301da177e4SLinus Torvalds /* 10311da177e4SLinus Torvalds * Now that we have a complete pe list we can start the copying. 10321da177e4SLinus Torvalds */ 1033eccf0817SAlasdair G Kergon list_for_each_entry_safe(pe, next_pe, &pe_queue, list) 10341da177e4SLinus Torvalds start_copy(pe); 10351da177e4SLinus Torvalds 1036b4b610f6SAlasdair G Kergon out: 10371da177e4SLinus Torvalds return r; 10381da177e4SLinus Torvalds } 10391da177e4SLinus Torvalds 10401da177e4SLinus Torvalds /* 10411da177e4SLinus Torvalds * Called on a write from the origin driver. 10421da177e4SLinus Torvalds */ 10431da177e4SLinus Torvalds static int do_origin(struct dm_dev *origin, struct bio *bio) 10441da177e4SLinus Torvalds { 10451da177e4SLinus Torvalds struct origin *o; 10461da177e4SLinus Torvalds int r = 1; 10471da177e4SLinus Torvalds 10481da177e4SLinus Torvalds down_read(&_origins_lock); 10491da177e4SLinus Torvalds o = __lookup_origin(origin->bdev); 10501da177e4SLinus Torvalds if (o) 10511da177e4SLinus Torvalds r = __origin_write(&o->snapshots, bio); 10521da177e4SLinus Torvalds up_read(&_origins_lock); 10531da177e4SLinus Torvalds 10541da177e4SLinus Torvalds return r; 10551da177e4SLinus Torvalds } 10561da177e4SLinus Torvalds 10571da177e4SLinus Torvalds /* 10581da177e4SLinus Torvalds * Origin: maps a linear range of a device, with hooks for snapshotting. 10591da177e4SLinus Torvalds */ 10601da177e4SLinus Torvalds 10611da177e4SLinus Torvalds /* 10621da177e4SLinus Torvalds * Construct an origin mapping: <dev_path> 10631da177e4SLinus Torvalds * The context for an origin is merely a 'struct dm_dev *' 10641da177e4SLinus Torvalds * pointing to the real device. 10651da177e4SLinus Torvalds */ 10661da177e4SLinus Torvalds static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv) 10671da177e4SLinus Torvalds { 10681da177e4SLinus Torvalds int r; 10691da177e4SLinus Torvalds struct dm_dev *dev; 10701da177e4SLinus Torvalds 10711da177e4SLinus Torvalds if (argc != 1) { 10721da177e4SLinus Torvalds ti->error = "dm-origin: incorrect number of arguments"; 10731da177e4SLinus Torvalds return -EINVAL; 10741da177e4SLinus Torvalds } 10751da177e4SLinus Torvalds 10761da177e4SLinus Torvalds r = dm_get_device(ti, argv[0], 0, ti->len, 10771da177e4SLinus Torvalds dm_table_get_mode(ti->table), &dev); 10781da177e4SLinus Torvalds if (r) { 10791da177e4SLinus Torvalds ti->error = "Cannot get target device"; 10801da177e4SLinus Torvalds return r; 10811da177e4SLinus Torvalds } 10821da177e4SLinus Torvalds 10831da177e4SLinus Torvalds ti->private = dev; 10841da177e4SLinus Torvalds return 0; 10851da177e4SLinus Torvalds } 10861da177e4SLinus Torvalds 10871da177e4SLinus Torvalds static void origin_dtr(struct dm_target *ti) 10881da177e4SLinus Torvalds { 10891da177e4SLinus Torvalds struct dm_dev *dev = (struct dm_dev *) ti->private; 10901da177e4SLinus Torvalds dm_put_device(ti, dev); 10911da177e4SLinus Torvalds } 10921da177e4SLinus Torvalds 10931da177e4SLinus Torvalds static int origin_map(struct dm_target *ti, struct bio *bio, 10941da177e4SLinus Torvalds union map_info *map_context) 10951da177e4SLinus Torvalds { 10961da177e4SLinus Torvalds struct dm_dev *dev = (struct dm_dev *) ti->private; 10971da177e4SLinus Torvalds bio->bi_bdev = dev->bdev; 10981da177e4SLinus Torvalds 10994aac0a63SAlasdair G Kergon if (unlikely(bio_barrier(bio))) 11004aac0a63SAlasdair G Kergon return -EOPNOTSUPP; 11014aac0a63SAlasdair G Kergon 11021da177e4SLinus Torvalds /* Only tell snapshots if this is a write */ 11031da177e4SLinus Torvalds return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : 1; 11041da177e4SLinus Torvalds } 11051da177e4SLinus Torvalds 11061da177e4SLinus Torvalds #define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r)) 11071da177e4SLinus Torvalds 11081da177e4SLinus Torvalds /* 11091da177e4SLinus Torvalds * Set the target "split_io" field to the minimum of all the snapshots' 11101da177e4SLinus Torvalds * chunk sizes. 11111da177e4SLinus Torvalds */ 11121da177e4SLinus Torvalds static void origin_resume(struct dm_target *ti) 11131da177e4SLinus Torvalds { 11141da177e4SLinus Torvalds struct dm_dev *dev = (struct dm_dev *) ti->private; 11151da177e4SLinus Torvalds struct dm_snapshot *snap; 11161da177e4SLinus Torvalds struct origin *o; 11171da177e4SLinus Torvalds chunk_t chunk_size = 0; 11181da177e4SLinus Torvalds 11191da177e4SLinus Torvalds down_read(&_origins_lock); 11201da177e4SLinus Torvalds o = __lookup_origin(dev->bdev); 11211da177e4SLinus Torvalds if (o) 11221da177e4SLinus Torvalds list_for_each_entry (snap, &o->snapshots, list) 11231da177e4SLinus Torvalds chunk_size = min_not_zero(chunk_size, snap->chunk_size); 11241da177e4SLinus Torvalds up_read(&_origins_lock); 11251da177e4SLinus Torvalds 11261da177e4SLinus Torvalds ti->split_io = chunk_size; 11271da177e4SLinus Torvalds } 11281da177e4SLinus Torvalds 11291da177e4SLinus Torvalds static int origin_status(struct dm_target *ti, status_type_t type, char *result, 11301da177e4SLinus Torvalds unsigned int maxlen) 11311da177e4SLinus Torvalds { 11321da177e4SLinus Torvalds struct dm_dev *dev = (struct dm_dev *) ti->private; 11331da177e4SLinus Torvalds 11341da177e4SLinus Torvalds switch (type) { 11351da177e4SLinus Torvalds case STATUSTYPE_INFO: 11361da177e4SLinus Torvalds result[0] = '\0'; 11371da177e4SLinus Torvalds break; 11381da177e4SLinus Torvalds 11391da177e4SLinus Torvalds case STATUSTYPE_TABLE: 11401da177e4SLinus Torvalds snprintf(result, maxlen, "%s", dev->name); 11411da177e4SLinus Torvalds break; 11421da177e4SLinus Torvalds } 11431da177e4SLinus Torvalds 11441da177e4SLinus Torvalds return 0; 11451da177e4SLinus Torvalds } 11461da177e4SLinus Torvalds 11471da177e4SLinus Torvalds static struct target_type origin_target = { 11481da177e4SLinus Torvalds .name = "snapshot-origin", 1149aa14edebSAlasdair G Kergon .version = {1, 1, 0}, 11501da177e4SLinus Torvalds .module = THIS_MODULE, 11511da177e4SLinus Torvalds .ctr = origin_ctr, 11521da177e4SLinus Torvalds .dtr = origin_dtr, 11531da177e4SLinus Torvalds .map = origin_map, 11541da177e4SLinus Torvalds .resume = origin_resume, 11551da177e4SLinus Torvalds .status = origin_status, 11561da177e4SLinus Torvalds }; 11571da177e4SLinus Torvalds 11581da177e4SLinus Torvalds static struct target_type snapshot_target = { 11591da177e4SLinus Torvalds .name = "snapshot", 1160aa14edebSAlasdair G Kergon .version = {1, 1, 0}, 11611da177e4SLinus Torvalds .module = THIS_MODULE, 11621da177e4SLinus Torvalds .ctr = snapshot_ctr, 11631da177e4SLinus Torvalds .dtr = snapshot_dtr, 11641da177e4SLinus Torvalds .map = snapshot_map, 11651da177e4SLinus Torvalds .resume = snapshot_resume, 11661da177e4SLinus Torvalds .status = snapshot_status, 11671da177e4SLinus Torvalds }; 11681da177e4SLinus Torvalds 11691da177e4SLinus Torvalds static int __init dm_snapshot_init(void) 11701da177e4SLinus Torvalds { 11711da177e4SLinus Torvalds int r; 11721da177e4SLinus Torvalds 11731da177e4SLinus Torvalds r = dm_register_target(&snapshot_target); 11741da177e4SLinus Torvalds if (r) { 11751da177e4SLinus Torvalds DMERR("snapshot target register failed %d", r); 11761da177e4SLinus Torvalds return r; 11771da177e4SLinus Torvalds } 11781da177e4SLinus Torvalds 11791da177e4SLinus Torvalds r = dm_register_target(&origin_target); 11801da177e4SLinus Torvalds if (r < 0) { 11811da177e4SLinus Torvalds DMERR("Device mapper: Origin: register failed %d\n", r); 11821da177e4SLinus Torvalds goto bad1; 11831da177e4SLinus Torvalds } 11841da177e4SLinus Torvalds 11851da177e4SLinus Torvalds r = init_origin_hash(); 11861da177e4SLinus Torvalds if (r) { 11871da177e4SLinus Torvalds DMERR("init_origin_hash failed."); 11881da177e4SLinus Torvalds goto bad2; 11891da177e4SLinus Torvalds } 11901da177e4SLinus Torvalds 11911da177e4SLinus Torvalds exception_cache = kmem_cache_create("dm-snapshot-ex", 11921da177e4SLinus Torvalds sizeof(struct exception), 11931da177e4SLinus Torvalds __alignof__(struct exception), 11941da177e4SLinus Torvalds 0, NULL, NULL); 11951da177e4SLinus Torvalds if (!exception_cache) { 11961da177e4SLinus Torvalds DMERR("Couldn't create exception cache."); 11971da177e4SLinus Torvalds r = -ENOMEM; 11981da177e4SLinus Torvalds goto bad3; 11991da177e4SLinus Torvalds } 12001da177e4SLinus Torvalds 12011da177e4SLinus Torvalds pending_cache = 12021da177e4SLinus Torvalds kmem_cache_create("dm-snapshot-in", 12031da177e4SLinus Torvalds sizeof(struct pending_exception), 12041da177e4SLinus Torvalds __alignof__(struct pending_exception), 12051da177e4SLinus Torvalds 0, NULL, NULL); 12061da177e4SLinus Torvalds if (!pending_cache) { 12071da177e4SLinus Torvalds DMERR("Couldn't create pending cache."); 12081da177e4SLinus Torvalds r = -ENOMEM; 12091da177e4SLinus Torvalds goto bad4; 12101da177e4SLinus Torvalds } 12111da177e4SLinus Torvalds 121293d2341cSMatthew Dobson pending_pool = mempool_create_slab_pool(128, pending_cache); 12131da177e4SLinus Torvalds if (!pending_pool) { 12141da177e4SLinus Torvalds DMERR("Couldn't create pending pool."); 12151da177e4SLinus Torvalds r = -ENOMEM; 12161da177e4SLinus Torvalds goto bad5; 12171da177e4SLinus Torvalds } 12181da177e4SLinus Torvalds 12191da177e4SLinus Torvalds return 0; 12201da177e4SLinus Torvalds 12211da177e4SLinus Torvalds bad5: 12221da177e4SLinus Torvalds kmem_cache_destroy(pending_cache); 12231da177e4SLinus Torvalds bad4: 12241da177e4SLinus Torvalds kmem_cache_destroy(exception_cache); 12251da177e4SLinus Torvalds bad3: 12261da177e4SLinus Torvalds exit_origin_hash(); 12271da177e4SLinus Torvalds bad2: 12281da177e4SLinus Torvalds dm_unregister_target(&origin_target); 12291da177e4SLinus Torvalds bad1: 12301da177e4SLinus Torvalds dm_unregister_target(&snapshot_target); 12311da177e4SLinus Torvalds return r; 12321da177e4SLinus Torvalds } 12331da177e4SLinus Torvalds 12341da177e4SLinus Torvalds static void __exit dm_snapshot_exit(void) 12351da177e4SLinus Torvalds { 12361da177e4SLinus Torvalds int r; 12371da177e4SLinus Torvalds 12381da177e4SLinus Torvalds r = dm_unregister_target(&snapshot_target); 12391da177e4SLinus Torvalds if (r) 12401da177e4SLinus Torvalds DMERR("snapshot unregister failed %d", r); 12411da177e4SLinus Torvalds 12421da177e4SLinus Torvalds r = dm_unregister_target(&origin_target); 12431da177e4SLinus Torvalds if (r) 12441da177e4SLinus Torvalds DMERR("origin unregister failed %d", r); 12451da177e4SLinus Torvalds 12461da177e4SLinus Torvalds exit_origin_hash(); 12471da177e4SLinus Torvalds mempool_destroy(pending_pool); 12481da177e4SLinus Torvalds kmem_cache_destroy(pending_cache); 12491da177e4SLinus Torvalds kmem_cache_destroy(exception_cache); 12501da177e4SLinus Torvalds } 12511da177e4SLinus Torvalds 12521da177e4SLinus Torvalds /* Module hooks */ 12531da177e4SLinus Torvalds module_init(dm_snapshot_init); 12541da177e4SLinus Torvalds module_exit(dm_snapshot_exit); 12551da177e4SLinus Torvalds 12561da177e4SLinus Torvalds MODULE_DESCRIPTION(DM_NAME " snapshot target"); 12571da177e4SLinus Torvalds MODULE_AUTHOR("Joe Thornber"); 12581da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 1259