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/ctype.h> 111da177e4SLinus Torvalds #include <linux/device-mapper.h> 121da177e4SLinus Torvalds #include <linux/fs.h> 131da177e4SLinus Torvalds #include <linux/init.h> 141da177e4SLinus Torvalds #include <linux/kdev_t.h> 151da177e4SLinus Torvalds #include <linux/list.h> 161da177e4SLinus Torvalds #include <linux/mempool.h> 171da177e4SLinus Torvalds #include <linux/module.h> 181da177e4SLinus Torvalds #include <linux/slab.h> 191da177e4SLinus Torvalds #include <linux/vmalloc.h> 201da177e4SLinus Torvalds 211da177e4SLinus Torvalds #include "dm-snap.h" 221da177e4SLinus Torvalds #include "dm-bio-list.h" 231da177e4SLinus Torvalds #include "kcopyd.h" 241da177e4SLinus Torvalds 2572d94861SAlasdair G Kergon #define DM_MSG_PREFIX "snapshots" 2672d94861SAlasdair G Kergon 271da177e4SLinus Torvalds /* 281da177e4SLinus Torvalds * The percentage increment we will wake up users at 291da177e4SLinus Torvalds */ 301da177e4SLinus Torvalds #define WAKE_UP_PERCENT 5 311da177e4SLinus Torvalds 321da177e4SLinus Torvalds /* 331da177e4SLinus Torvalds * kcopyd priority of snapshot operations 341da177e4SLinus Torvalds */ 351da177e4SLinus Torvalds #define SNAPSHOT_COPY_PRIORITY 2 361da177e4SLinus Torvalds 371da177e4SLinus Torvalds /* 381da177e4SLinus Torvalds * Each snapshot reserves this many pages for io 391da177e4SLinus Torvalds */ 401da177e4SLinus Torvalds #define SNAPSHOT_PAGES 256 411da177e4SLinus Torvalds 42ca3a931fSAlasdair G Kergon struct workqueue_struct *ksnapd; 43c4028958SDavid Howells static void flush_queued_bios(struct work_struct *work); 44ca3a931fSAlasdair G Kergon 451da177e4SLinus Torvalds struct pending_exception { 461da177e4SLinus Torvalds struct exception e; 471da177e4SLinus Torvalds 481da177e4SLinus Torvalds /* 491da177e4SLinus Torvalds * Origin buffers waiting for this to complete are held 501da177e4SLinus Torvalds * in a bio list 511da177e4SLinus Torvalds */ 521da177e4SLinus Torvalds struct bio_list origin_bios; 531da177e4SLinus Torvalds struct bio_list snapshot_bios; 541da177e4SLinus Torvalds 551da177e4SLinus Torvalds /* 56eccf0817SAlasdair G Kergon * Short-term queue of pending exceptions prior to submission. 57eccf0817SAlasdair G Kergon */ 58eccf0817SAlasdair G Kergon struct list_head list; 59eccf0817SAlasdair G Kergon 60eccf0817SAlasdair G Kergon /* 61b4b610f6SAlasdair G Kergon * The primary pending_exception is the one that holds 624b832e8dSAlasdair G Kergon * the ref_count and the list of origin_bios for a 63b4b610f6SAlasdair G Kergon * group of pending_exceptions. It is always last to get freed. 64b4b610f6SAlasdair G Kergon * These fields get set up when writing to the origin. 651da177e4SLinus Torvalds */ 66b4b610f6SAlasdair G Kergon struct pending_exception *primary_pe; 67b4b610f6SAlasdair G Kergon 68b4b610f6SAlasdair G Kergon /* 69b4b610f6SAlasdair G Kergon * Number of pending_exceptions processing this chunk. 70b4b610f6SAlasdair G Kergon * When this drops to zero we must complete the origin bios. 71b4b610f6SAlasdair G Kergon * If incrementing or decrementing this, hold pe->snap->lock for 72b4b610f6SAlasdair G Kergon * the sibling concerned and not pe->primary_pe->snap->lock unless 73b4b610f6SAlasdair G Kergon * they are the same. 74b4b610f6SAlasdair G Kergon */ 754b832e8dSAlasdair G Kergon atomic_t ref_count; 761da177e4SLinus Torvalds 771da177e4SLinus Torvalds /* Pointer back to snapshot context */ 781da177e4SLinus Torvalds struct dm_snapshot *snap; 791da177e4SLinus Torvalds 801da177e4SLinus Torvalds /* 811da177e4SLinus Torvalds * 1 indicates the exception has already been sent to 821da177e4SLinus Torvalds * kcopyd. 831da177e4SLinus Torvalds */ 841da177e4SLinus Torvalds int started; 851da177e4SLinus Torvalds }; 861da177e4SLinus Torvalds 871da177e4SLinus Torvalds /* 881da177e4SLinus Torvalds * Hash table mapping origin volumes to lists of snapshots and 891da177e4SLinus Torvalds * a lock to protect it 901da177e4SLinus Torvalds */ 91e18b890bSChristoph Lameter static struct kmem_cache *exception_cache; 92e18b890bSChristoph Lameter static struct kmem_cache *pending_cache; 931da177e4SLinus Torvalds static mempool_t *pending_pool; 941da177e4SLinus Torvalds 951da177e4SLinus Torvalds /* 961da177e4SLinus Torvalds * One of these per registered origin, held in the snapshot_origins hash 971da177e4SLinus Torvalds */ 981da177e4SLinus Torvalds struct origin { 991da177e4SLinus Torvalds /* The origin device */ 1001da177e4SLinus Torvalds struct block_device *bdev; 1011da177e4SLinus Torvalds 1021da177e4SLinus Torvalds struct list_head hash_list; 1031da177e4SLinus Torvalds 1041da177e4SLinus Torvalds /* List of snapshots for this origin */ 1051da177e4SLinus Torvalds struct list_head snapshots; 1061da177e4SLinus Torvalds }; 1071da177e4SLinus Torvalds 1081da177e4SLinus Torvalds /* 1091da177e4SLinus Torvalds * Size of the hash table for origin volumes. If we make this 1101da177e4SLinus Torvalds * the size of the minors list then it should be nearly perfect 1111da177e4SLinus Torvalds */ 1121da177e4SLinus Torvalds #define ORIGIN_HASH_SIZE 256 1131da177e4SLinus Torvalds #define ORIGIN_MASK 0xFF 1141da177e4SLinus Torvalds static struct list_head *_origins; 1151da177e4SLinus Torvalds static struct rw_semaphore _origins_lock; 1161da177e4SLinus Torvalds 1171da177e4SLinus Torvalds static int init_origin_hash(void) 1181da177e4SLinus Torvalds { 1191da177e4SLinus Torvalds int i; 1201da177e4SLinus Torvalds 1211da177e4SLinus Torvalds _origins = kmalloc(ORIGIN_HASH_SIZE * sizeof(struct list_head), 1221da177e4SLinus Torvalds GFP_KERNEL); 1231da177e4SLinus Torvalds if (!_origins) { 12472d94861SAlasdair G Kergon DMERR("unable to allocate memory"); 1251da177e4SLinus Torvalds return -ENOMEM; 1261da177e4SLinus Torvalds } 1271da177e4SLinus Torvalds 1281da177e4SLinus Torvalds for (i = 0; i < ORIGIN_HASH_SIZE; i++) 1291da177e4SLinus Torvalds INIT_LIST_HEAD(_origins + i); 1301da177e4SLinus Torvalds init_rwsem(&_origins_lock); 1311da177e4SLinus Torvalds 1321da177e4SLinus Torvalds return 0; 1331da177e4SLinus Torvalds } 1341da177e4SLinus Torvalds 1351da177e4SLinus Torvalds static void exit_origin_hash(void) 1361da177e4SLinus Torvalds { 1371da177e4SLinus Torvalds kfree(_origins); 1381da177e4SLinus Torvalds } 1391da177e4SLinus Torvalds 1401da177e4SLinus Torvalds static inline unsigned int origin_hash(struct block_device *bdev) 1411da177e4SLinus Torvalds { 1421da177e4SLinus Torvalds return bdev->bd_dev & ORIGIN_MASK; 1431da177e4SLinus Torvalds } 1441da177e4SLinus Torvalds 1451da177e4SLinus Torvalds static struct origin *__lookup_origin(struct block_device *origin) 1461da177e4SLinus Torvalds { 1471da177e4SLinus Torvalds struct list_head *ol; 1481da177e4SLinus Torvalds struct origin *o; 1491da177e4SLinus Torvalds 1501da177e4SLinus Torvalds ol = &_origins[origin_hash(origin)]; 1511da177e4SLinus Torvalds list_for_each_entry (o, ol, hash_list) 1521da177e4SLinus Torvalds if (bdev_equal(o->bdev, origin)) 1531da177e4SLinus Torvalds return o; 1541da177e4SLinus Torvalds 1551da177e4SLinus Torvalds return NULL; 1561da177e4SLinus Torvalds } 1571da177e4SLinus Torvalds 1581da177e4SLinus Torvalds static void __insert_origin(struct origin *o) 1591da177e4SLinus Torvalds { 1601da177e4SLinus Torvalds struct list_head *sl = &_origins[origin_hash(o->bdev)]; 1611da177e4SLinus Torvalds list_add_tail(&o->hash_list, sl); 1621da177e4SLinus Torvalds } 1631da177e4SLinus Torvalds 1641da177e4SLinus Torvalds /* 1651da177e4SLinus Torvalds * Make a note of the snapshot and its origin so we can look it 1661da177e4SLinus Torvalds * up when the origin has a write on it. 1671da177e4SLinus Torvalds */ 1681da177e4SLinus Torvalds static int register_snapshot(struct dm_snapshot *snap) 1691da177e4SLinus Torvalds { 1701da177e4SLinus Torvalds struct origin *o; 1711da177e4SLinus Torvalds struct block_device *bdev = snap->origin->bdev; 1721da177e4SLinus Torvalds 1731da177e4SLinus Torvalds down_write(&_origins_lock); 1741da177e4SLinus Torvalds o = __lookup_origin(bdev); 1751da177e4SLinus Torvalds 1761da177e4SLinus Torvalds if (!o) { 1771da177e4SLinus Torvalds /* New origin */ 1781da177e4SLinus Torvalds o = kmalloc(sizeof(*o), GFP_KERNEL); 1791da177e4SLinus Torvalds if (!o) { 1801da177e4SLinus Torvalds up_write(&_origins_lock); 1811da177e4SLinus Torvalds return -ENOMEM; 1821da177e4SLinus Torvalds } 1831da177e4SLinus Torvalds 1841da177e4SLinus Torvalds /* Initialise the struct */ 1851da177e4SLinus Torvalds INIT_LIST_HEAD(&o->snapshots); 1861da177e4SLinus Torvalds o->bdev = bdev; 1871da177e4SLinus Torvalds 1881da177e4SLinus Torvalds __insert_origin(o); 1891da177e4SLinus Torvalds } 1901da177e4SLinus Torvalds 1911da177e4SLinus Torvalds list_add_tail(&snap->list, &o->snapshots); 1921da177e4SLinus Torvalds 1931da177e4SLinus Torvalds up_write(&_origins_lock); 1941da177e4SLinus Torvalds return 0; 1951da177e4SLinus Torvalds } 1961da177e4SLinus Torvalds 1971da177e4SLinus Torvalds static void unregister_snapshot(struct dm_snapshot *s) 1981da177e4SLinus Torvalds { 1991da177e4SLinus Torvalds struct origin *o; 2001da177e4SLinus Torvalds 2011da177e4SLinus Torvalds down_write(&_origins_lock); 2021da177e4SLinus Torvalds o = __lookup_origin(s->origin->bdev); 2031da177e4SLinus Torvalds 2041da177e4SLinus Torvalds list_del(&s->list); 2051da177e4SLinus Torvalds if (list_empty(&o->snapshots)) { 2061da177e4SLinus Torvalds list_del(&o->hash_list); 2071da177e4SLinus Torvalds kfree(o); 2081da177e4SLinus Torvalds } 2091da177e4SLinus Torvalds 2101da177e4SLinus Torvalds up_write(&_origins_lock); 2111da177e4SLinus Torvalds } 2121da177e4SLinus Torvalds 2131da177e4SLinus Torvalds /* 2141da177e4SLinus Torvalds * Implementation of the exception hash tables. 2151da177e4SLinus Torvalds */ 2161da177e4SLinus Torvalds static int init_exception_table(struct exception_table *et, uint32_t size) 2171da177e4SLinus Torvalds { 2181da177e4SLinus Torvalds unsigned int i; 2191da177e4SLinus Torvalds 2201da177e4SLinus Torvalds et->hash_mask = size - 1; 2211da177e4SLinus Torvalds et->table = dm_vcalloc(size, sizeof(struct list_head)); 2221da177e4SLinus Torvalds if (!et->table) 2231da177e4SLinus Torvalds return -ENOMEM; 2241da177e4SLinus Torvalds 2251da177e4SLinus Torvalds for (i = 0; i < size; i++) 2261da177e4SLinus Torvalds INIT_LIST_HEAD(et->table + i); 2271da177e4SLinus Torvalds 2281da177e4SLinus Torvalds return 0; 2291da177e4SLinus Torvalds } 2301da177e4SLinus Torvalds 231e18b890bSChristoph Lameter static void exit_exception_table(struct exception_table *et, struct kmem_cache *mem) 2321da177e4SLinus Torvalds { 2331da177e4SLinus Torvalds struct list_head *slot; 2341da177e4SLinus Torvalds struct exception *ex, *next; 2351da177e4SLinus Torvalds int i, size; 2361da177e4SLinus Torvalds 2371da177e4SLinus Torvalds size = et->hash_mask + 1; 2381da177e4SLinus Torvalds for (i = 0; i < size; i++) { 2391da177e4SLinus Torvalds slot = et->table + i; 2401da177e4SLinus Torvalds 2411da177e4SLinus Torvalds list_for_each_entry_safe (ex, next, slot, hash_list) 2421da177e4SLinus Torvalds kmem_cache_free(mem, ex); 2431da177e4SLinus Torvalds } 2441da177e4SLinus Torvalds 2451da177e4SLinus Torvalds vfree(et->table); 2461da177e4SLinus Torvalds } 2471da177e4SLinus Torvalds 2481da177e4SLinus Torvalds static inline uint32_t exception_hash(struct exception_table *et, chunk_t chunk) 2491da177e4SLinus Torvalds { 2501da177e4SLinus Torvalds return chunk & et->hash_mask; 2511da177e4SLinus Torvalds } 2521da177e4SLinus Torvalds 2531da177e4SLinus Torvalds static void insert_exception(struct exception_table *eh, struct exception *e) 2541da177e4SLinus Torvalds { 2551da177e4SLinus Torvalds struct list_head *l = &eh->table[exception_hash(eh, e->old_chunk)]; 2561da177e4SLinus Torvalds list_add(&e->hash_list, l); 2571da177e4SLinus Torvalds } 2581da177e4SLinus Torvalds 2591da177e4SLinus Torvalds static inline void remove_exception(struct exception *e) 2601da177e4SLinus Torvalds { 2611da177e4SLinus Torvalds list_del(&e->hash_list); 2621da177e4SLinus Torvalds } 2631da177e4SLinus Torvalds 2641da177e4SLinus Torvalds /* 2651da177e4SLinus Torvalds * Return the exception data for a sector, or NULL if not 2661da177e4SLinus Torvalds * remapped. 2671da177e4SLinus Torvalds */ 2681da177e4SLinus Torvalds static struct exception *lookup_exception(struct exception_table *et, 2691da177e4SLinus Torvalds chunk_t chunk) 2701da177e4SLinus Torvalds { 2711da177e4SLinus Torvalds struct list_head *slot; 2721da177e4SLinus Torvalds struct exception *e; 2731da177e4SLinus Torvalds 2741da177e4SLinus Torvalds slot = &et->table[exception_hash(et, chunk)]; 2751da177e4SLinus Torvalds list_for_each_entry (e, slot, hash_list) 2761da177e4SLinus Torvalds if (e->old_chunk == chunk) 2771da177e4SLinus Torvalds return e; 2781da177e4SLinus Torvalds 2791da177e4SLinus Torvalds return NULL; 2801da177e4SLinus Torvalds } 2811da177e4SLinus Torvalds 2821da177e4SLinus Torvalds static inline struct exception *alloc_exception(void) 2831da177e4SLinus Torvalds { 2841da177e4SLinus Torvalds struct exception *e; 2851da177e4SLinus Torvalds 2861da177e4SLinus Torvalds e = kmem_cache_alloc(exception_cache, GFP_NOIO); 2871da177e4SLinus Torvalds if (!e) 2881da177e4SLinus Torvalds e = kmem_cache_alloc(exception_cache, GFP_ATOMIC); 2891da177e4SLinus Torvalds 2901da177e4SLinus Torvalds return e; 2911da177e4SLinus Torvalds } 2921da177e4SLinus Torvalds 2931da177e4SLinus Torvalds static inline void free_exception(struct exception *e) 2941da177e4SLinus Torvalds { 2951da177e4SLinus Torvalds kmem_cache_free(exception_cache, e); 2961da177e4SLinus Torvalds } 2971da177e4SLinus Torvalds 2981da177e4SLinus Torvalds static inline struct pending_exception *alloc_pending_exception(void) 2991da177e4SLinus Torvalds { 3001da177e4SLinus Torvalds return mempool_alloc(pending_pool, GFP_NOIO); 3011da177e4SLinus Torvalds } 3021da177e4SLinus Torvalds 3031da177e4SLinus Torvalds static inline void free_pending_exception(struct pending_exception *pe) 3041da177e4SLinus Torvalds { 3051da177e4SLinus Torvalds mempool_free(pe, pending_pool); 3061da177e4SLinus Torvalds } 3071da177e4SLinus Torvalds 3081da177e4SLinus Torvalds int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new) 3091da177e4SLinus Torvalds { 3101da177e4SLinus Torvalds struct exception *e; 3111da177e4SLinus Torvalds 3121da177e4SLinus Torvalds e = alloc_exception(); 3131da177e4SLinus Torvalds if (!e) 3141da177e4SLinus Torvalds return -ENOMEM; 3151da177e4SLinus Torvalds 3161da177e4SLinus Torvalds e->old_chunk = old; 3171da177e4SLinus Torvalds e->new_chunk = new; 3181da177e4SLinus Torvalds insert_exception(&s->complete, e); 3191da177e4SLinus Torvalds return 0; 3201da177e4SLinus Torvalds } 3211da177e4SLinus Torvalds 3221da177e4SLinus Torvalds /* 3231da177e4SLinus Torvalds * Hard coded magic. 3241da177e4SLinus Torvalds */ 3251da177e4SLinus Torvalds static int calc_max_buckets(void) 3261da177e4SLinus Torvalds { 3271da177e4SLinus Torvalds /* use a fixed size of 2MB */ 3281da177e4SLinus Torvalds unsigned long mem = 2 * 1024 * 1024; 3291da177e4SLinus Torvalds mem /= sizeof(struct list_head); 3301da177e4SLinus Torvalds 3311da177e4SLinus Torvalds return mem; 3321da177e4SLinus Torvalds } 3331da177e4SLinus Torvalds 3341da177e4SLinus Torvalds /* 3351da177e4SLinus Torvalds * Rounds a number down to a power of 2. 3361da177e4SLinus Torvalds */ 3371da177e4SLinus Torvalds static inline uint32_t round_down(uint32_t n) 3381da177e4SLinus Torvalds { 3391da177e4SLinus Torvalds while (n & (n - 1)) 3401da177e4SLinus Torvalds n &= (n - 1); 3411da177e4SLinus Torvalds return n; 3421da177e4SLinus Torvalds } 3431da177e4SLinus Torvalds 3441da177e4SLinus Torvalds /* 3451da177e4SLinus Torvalds * Allocate room for a suitable hash table. 3461da177e4SLinus Torvalds */ 3471da177e4SLinus Torvalds static int init_hash_tables(struct dm_snapshot *s) 3481da177e4SLinus Torvalds { 3491da177e4SLinus Torvalds sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets; 3501da177e4SLinus Torvalds 3511da177e4SLinus Torvalds /* 3521da177e4SLinus Torvalds * Calculate based on the size of the original volume or 3531da177e4SLinus Torvalds * the COW volume... 3541da177e4SLinus Torvalds */ 3551da177e4SLinus Torvalds cow_dev_size = get_dev_size(s->cow->bdev); 3561da177e4SLinus Torvalds origin_dev_size = get_dev_size(s->origin->bdev); 3571da177e4SLinus Torvalds max_buckets = calc_max_buckets(); 3581da177e4SLinus Torvalds 3591da177e4SLinus Torvalds hash_size = min(origin_dev_size, cow_dev_size) >> s->chunk_shift; 3601da177e4SLinus Torvalds hash_size = min(hash_size, max_buckets); 3611da177e4SLinus Torvalds 3621da177e4SLinus Torvalds /* Round it down to a power of 2 */ 3631da177e4SLinus Torvalds hash_size = round_down(hash_size); 3641da177e4SLinus Torvalds if (init_exception_table(&s->complete, hash_size)) 3651da177e4SLinus Torvalds return -ENOMEM; 3661da177e4SLinus Torvalds 3671da177e4SLinus Torvalds /* 3681da177e4SLinus Torvalds * Allocate hash table for in-flight exceptions 3691da177e4SLinus Torvalds * Make this smaller than the real hash table 3701da177e4SLinus Torvalds */ 3711da177e4SLinus Torvalds hash_size >>= 3; 3721da177e4SLinus Torvalds if (hash_size < 64) 3731da177e4SLinus Torvalds hash_size = 64; 3741da177e4SLinus Torvalds 3751da177e4SLinus Torvalds if (init_exception_table(&s->pending, hash_size)) { 3761da177e4SLinus Torvalds exit_exception_table(&s->complete, exception_cache); 3771da177e4SLinus Torvalds return -ENOMEM; 3781da177e4SLinus Torvalds } 3791da177e4SLinus Torvalds 3801da177e4SLinus Torvalds return 0; 3811da177e4SLinus Torvalds } 3821da177e4SLinus Torvalds 3831da177e4SLinus Torvalds /* 3841da177e4SLinus Torvalds * Round a number up to the nearest 'size' boundary. size must 3851da177e4SLinus Torvalds * be a power of 2. 3861da177e4SLinus Torvalds */ 3871da177e4SLinus Torvalds static inline ulong round_up(ulong n, ulong size) 3881da177e4SLinus Torvalds { 3891da177e4SLinus Torvalds size--; 3901da177e4SLinus Torvalds return (n + size) & ~size; 3911da177e4SLinus Torvalds } 3921da177e4SLinus Torvalds 3934c7e3bf4SMark McLoughlin static int set_chunk_size(struct dm_snapshot *s, const char *chunk_size_arg, 3944c7e3bf4SMark McLoughlin char **error) 3954c7e3bf4SMark McLoughlin { 3964c7e3bf4SMark McLoughlin unsigned long chunk_size; 3974c7e3bf4SMark McLoughlin char *value; 3984c7e3bf4SMark McLoughlin 3994c7e3bf4SMark McLoughlin chunk_size = simple_strtoul(chunk_size_arg, &value, 10); 4004c7e3bf4SMark McLoughlin if (*chunk_size_arg == '\0' || *value != '\0') { 4014c7e3bf4SMark McLoughlin *error = "Invalid chunk size"; 4024c7e3bf4SMark McLoughlin return -EINVAL; 4034c7e3bf4SMark McLoughlin } 4044c7e3bf4SMark McLoughlin 4054c7e3bf4SMark McLoughlin if (!chunk_size) { 4064c7e3bf4SMark McLoughlin s->chunk_size = s->chunk_mask = s->chunk_shift = 0; 4074c7e3bf4SMark McLoughlin return 0; 4084c7e3bf4SMark McLoughlin } 4094c7e3bf4SMark McLoughlin 4104c7e3bf4SMark McLoughlin /* 4114c7e3bf4SMark McLoughlin * Chunk size must be multiple of page size. Silently 4124c7e3bf4SMark McLoughlin * round up if it's not. 4134c7e3bf4SMark McLoughlin */ 4144c7e3bf4SMark McLoughlin chunk_size = round_up(chunk_size, PAGE_SIZE >> 9); 4154c7e3bf4SMark McLoughlin 4164c7e3bf4SMark McLoughlin /* Check chunk_size is a power of 2 */ 4174c7e3bf4SMark McLoughlin if (chunk_size & (chunk_size - 1)) { 4184c7e3bf4SMark McLoughlin *error = "Chunk size is not a power of 2"; 4194c7e3bf4SMark McLoughlin return -EINVAL; 4204c7e3bf4SMark McLoughlin } 4214c7e3bf4SMark McLoughlin 4224c7e3bf4SMark McLoughlin /* Validate the chunk size against the device block size */ 4234c7e3bf4SMark McLoughlin if (chunk_size % (bdev_hardsect_size(s->cow->bdev) >> 9)) { 4244c7e3bf4SMark McLoughlin *error = "Chunk size is not a multiple of device blocksize"; 4254c7e3bf4SMark McLoughlin return -EINVAL; 4264c7e3bf4SMark McLoughlin } 4274c7e3bf4SMark McLoughlin 4284c7e3bf4SMark McLoughlin s->chunk_size = chunk_size; 4294c7e3bf4SMark McLoughlin s->chunk_mask = chunk_size - 1; 4304c7e3bf4SMark McLoughlin s->chunk_shift = ffs(chunk_size) - 1; 4314c7e3bf4SMark McLoughlin 4324c7e3bf4SMark McLoughlin return 0; 4334c7e3bf4SMark McLoughlin } 4344c7e3bf4SMark McLoughlin 4351da177e4SLinus Torvalds /* 4361da177e4SLinus Torvalds * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size> 4371da177e4SLinus Torvalds */ 4381da177e4SLinus Torvalds static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) 4391da177e4SLinus Torvalds { 4401da177e4SLinus Torvalds struct dm_snapshot *s; 4411da177e4SLinus Torvalds int r = -EINVAL; 4421da177e4SLinus Torvalds char persistent; 4431da177e4SLinus Torvalds char *origin_path; 4441da177e4SLinus Torvalds char *cow_path; 4451da177e4SLinus Torvalds 4464c7e3bf4SMark McLoughlin if (argc != 4) { 44772d94861SAlasdair G Kergon ti->error = "requires exactly 4 arguments"; 4481da177e4SLinus Torvalds r = -EINVAL; 4491da177e4SLinus Torvalds goto bad1; 4501da177e4SLinus Torvalds } 4511da177e4SLinus Torvalds 4521da177e4SLinus Torvalds origin_path = argv[0]; 4531da177e4SLinus Torvalds cow_path = argv[1]; 4541da177e4SLinus Torvalds persistent = toupper(*argv[2]); 4551da177e4SLinus Torvalds 4561da177e4SLinus Torvalds if (persistent != 'P' && persistent != 'N') { 4571da177e4SLinus Torvalds ti->error = "Persistent flag is not P or N"; 4581da177e4SLinus Torvalds r = -EINVAL; 4591da177e4SLinus Torvalds goto bad1; 4601da177e4SLinus Torvalds } 4611da177e4SLinus Torvalds 4621da177e4SLinus Torvalds s = kmalloc(sizeof(*s), GFP_KERNEL); 4631da177e4SLinus Torvalds if (s == NULL) { 4641da177e4SLinus Torvalds ti->error = "Cannot allocate snapshot context private " 4651da177e4SLinus Torvalds "structure"; 4661da177e4SLinus Torvalds r = -ENOMEM; 4671da177e4SLinus Torvalds goto bad1; 4681da177e4SLinus Torvalds } 4691da177e4SLinus Torvalds 4701da177e4SLinus Torvalds r = dm_get_device(ti, origin_path, 0, ti->len, FMODE_READ, &s->origin); 4711da177e4SLinus Torvalds if (r) { 4721da177e4SLinus Torvalds ti->error = "Cannot get origin device"; 4731da177e4SLinus Torvalds goto bad2; 4741da177e4SLinus Torvalds } 4751da177e4SLinus Torvalds 4761da177e4SLinus Torvalds r = dm_get_device(ti, cow_path, 0, 0, 4771da177e4SLinus Torvalds FMODE_READ | FMODE_WRITE, &s->cow); 4781da177e4SLinus Torvalds if (r) { 4791da177e4SLinus Torvalds dm_put_device(ti, s->origin); 4801da177e4SLinus Torvalds ti->error = "Cannot get COW device"; 4811da177e4SLinus Torvalds goto bad2; 4821da177e4SLinus Torvalds } 4831da177e4SLinus Torvalds 4844c7e3bf4SMark McLoughlin r = set_chunk_size(s, argv[3], &ti->error); 4854c7e3bf4SMark McLoughlin if (r) 4861da177e4SLinus Torvalds goto bad3; 4871da177e4SLinus Torvalds 4881da177e4SLinus Torvalds s->type = persistent; 4891da177e4SLinus Torvalds 4901da177e4SLinus Torvalds s->valid = 1; 491aa14edebSAlasdair G Kergon s->active = 0; 4921da177e4SLinus Torvalds s->last_percent = 0; 4931da177e4SLinus Torvalds init_rwsem(&s->lock); 494ca3a931fSAlasdair G Kergon spin_lock_init(&s->pe_lock); 4951da177e4SLinus Torvalds s->table = ti->table; 4961da177e4SLinus Torvalds 4971da177e4SLinus Torvalds /* Allocate hash table for COW data */ 4981da177e4SLinus Torvalds if (init_hash_tables(s)) { 4991da177e4SLinus Torvalds ti->error = "Unable to allocate hash table space"; 5001da177e4SLinus Torvalds r = -ENOMEM; 5011da177e4SLinus Torvalds goto bad3; 5021da177e4SLinus Torvalds } 5031da177e4SLinus Torvalds 5041da177e4SLinus Torvalds s->store.snap = s; 5051da177e4SLinus Torvalds 5061da177e4SLinus Torvalds if (persistent == 'P') 5074c7e3bf4SMark McLoughlin r = dm_create_persistent(&s->store); 5081da177e4SLinus Torvalds else 5094c7e3bf4SMark McLoughlin r = dm_create_transient(&s->store); 5101da177e4SLinus Torvalds 5111da177e4SLinus Torvalds if (r) { 5121da177e4SLinus Torvalds ti->error = "Couldn't create exception store"; 5131da177e4SLinus Torvalds r = -EINVAL; 5141da177e4SLinus Torvalds goto bad4; 5151da177e4SLinus Torvalds } 5161da177e4SLinus Torvalds 5171da177e4SLinus Torvalds r = kcopyd_client_create(SNAPSHOT_PAGES, &s->kcopyd_client); 5181da177e4SLinus Torvalds if (r) { 5191da177e4SLinus Torvalds ti->error = "Could not create kcopyd client"; 5201da177e4SLinus Torvalds goto bad5; 5211da177e4SLinus Torvalds } 5221da177e4SLinus Torvalds 523aa14edebSAlasdair G Kergon /* Metadata must only be loaded into one table at once */ 524f9cea4f7SMark McLoughlin r = s->store.read_metadata(&s->store); 525f9cea4f7SMark McLoughlin if (r) { 526f9cea4f7SMark McLoughlin ti->error = "Failed to read snapshot metadata"; 527f9cea4f7SMark McLoughlin goto bad6; 528f9cea4f7SMark McLoughlin } 529aa14edebSAlasdair G Kergon 530ca3a931fSAlasdair G Kergon bio_list_init(&s->queued_bios); 531c4028958SDavid Howells INIT_WORK(&s->queued_bios_work, flush_queued_bios); 532ca3a931fSAlasdair G Kergon 5331da177e4SLinus Torvalds /* Add snapshot to the list of snapshots for this origin */ 534aa14edebSAlasdair G Kergon /* Exceptions aren't triggered till snapshot_resume() is called */ 5351da177e4SLinus Torvalds if (register_snapshot(s)) { 5361da177e4SLinus Torvalds r = -EINVAL; 5371da177e4SLinus Torvalds ti->error = "Cannot register snapshot origin"; 5381da177e4SLinus Torvalds goto bad6; 5391da177e4SLinus Torvalds } 5401da177e4SLinus Torvalds 5411da177e4SLinus Torvalds ti->private = s; 542c51c2752SAlasdair G Kergon ti->split_io = s->chunk_size; 5431da177e4SLinus Torvalds 5441da177e4SLinus Torvalds return 0; 5451da177e4SLinus Torvalds 5461da177e4SLinus Torvalds bad6: 5471da177e4SLinus Torvalds kcopyd_client_destroy(s->kcopyd_client); 5481da177e4SLinus Torvalds 5491da177e4SLinus Torvalds bad5: 5501da177e4SLinus Torvalds s->store.destroy(&s->store); 5511da177e4SLinus Torvalds 5521da177e4SLinus Torvalds bad4: 5531da177e4SLinus Torvalds exit_exception_table(&s->pending, pending_cache); 5541da177e4SLinus Torvalds exit_exception_table(&s->complete, exception_cache); 5551da177e4SLinus Torvalds 5561da177e4SLinus Torvalds bad3: 5571da177e4SLinus Torvalds dm_put_device(ti, s->cow); 5581da177e4SLinus Torvalds dm_put_device(ti, s->origin); 5591da177e4SLinus Torvalds 5601da177e4SLinus Torvalds bad2: 5611da177e4SLinus Torvalds kfree(s); 5621da177e4SLinus Torvalds 5631da177e4SLinus Torvalds bad1: 5641da177e4SLinus Torvalds return r; 5651da177e4SLinus Torvalds } 5661da177e4SLinus Torvalds 56731c93a0cSMilan Broz static void __free_exceptions(struct dm_snapshot *s) 56831c93a0cSMilan Broz { 56931c93a0cSMilan Broz kcopyd_client_destroy(s->kcopyd_client); 57031c93a0cSMilan Broz s->kcopyd_client = NULL; 57131c93a0cSMilan Broz 57231c93a0cSMilan Broz exit_exception_table(&s->pending, pending_cache); 57331c93a0cSMilan Broz exit_exception_table(&s->complete, exception_cache); 57431c93a0cSMilan Broz 57531c93a0cSMilan Broz s->store.destroy(&s->store); 57631c93a0cSMilan Broz } 57731c93a0cSMilan Broz 5781da177e4SLinus Torvalds static void snapshot_dtr(struct dm_target *ti) 5791da177e4SLinus Torvalds { 5801da177e4SLinus Torvalds struct dm_snapshot *s = (struct dm_snapshot *) ti->private; 5811da177e4SLinus Torvalds 582ca3a931fSAlasdair G Kergon flush_workqueue(ksnapd); 583ca3a931fSAlasdair G Kergon 584138728dcSAlasdair G Kergon /* Prevent further origin writes from using this snapshot. */ 585138728dcSAlasdair G Kergon /* After this returns there can be no new kcopyd jobs. */ 5861da177e4SLinus Torvalds unregister_snapshot(s); 5871da177e4SLinus Torvalds 58831c93a0cSMilan Broz __free_exceptions(s); 5891da177e4SLinus Torvalds 5901da177e4SLinus Torvalds dm_put_device(ti, s->origin); 5911da177e4SLinus Torvalds dm_put_device(ti, s->cow); 592138728dcSAlasdair G Kergon 5931da177e4SLinus Torvalds kfree(s); 5941da177e4SLinus Torvalds } 5951da177e4SLinus Torvalds 5961da177e4SLinus Torvalds /* 5971da177e4SLinus Torvalds * Flush a list of buffers. 5981da177e4SLinus Torvalds */ 5991da177e4SLinus Torvalds static void flush_bios(struct bio *bio) 6001da177e4SLinus Torvalds { 6011da177e4SLinus Torvalds struct bio *n; 6021da177e4SLinus Torvalds 6031da177e4SLinus Torvalds while (bio) { 6041da177e4SLinus Torvalds n = bio->bi_next; 6051da177e4SLinus Torvalds bio->bi_next = NULL; 6061da177e4SLinus Torvalds generic_make_request(bio); 6071da177e4SLinus Torvalds bio = n; 6081da177e4SLinus Torvalds } 6091da177e4SLinus Torvalds } 6101da177e4SLinus Torvalds 611c4028958SDavid Howells static void flush_queued_bios(struct work_struct *work) 612ca3a931fSAlasdair G Kergon { 613c4028958SDavid Howells struct dm_snapshot *s = 614c4028958SDavid Howells container_of(work, struct dm_snapshot, queued_bios_work); 615ca3a931fSAlasdair G Kergon struct bio *queued_bios; 616ca3a931fSAlasdair G Kergon unsigned long flags; 617ca3a931fSAlasdair G Kergon 618ca3a931fSAlasdair G Kergon spin_lock_irqsave(&s->pe_lock, flags); 619ca3a931fSAlasdair G Kergon queued_bios = bio_list_get(&s->queued_bios); 620ca3a931fSAlasdair G Kergon spin_unlock_irqrestore(&s->pe_lock, flags); 621ca3a931fSAlasdair G Kergon 622ca3a931fSAlasdair G Kergon flush_bios(queued_bios); 623ca3a931fSAlasdair G Kergon } 624ca3a931fSAlasdair G Kergon 6251da177e4SLinus Torvalds /* 6261da177e4SLinus Torvalds * Error a list of buffers. 6271da177e4SLinus Torvalds */ 6281da177e4SLinus Torvalds static void error_bios(struct bio *bio) 6291da177e4SLinus Torvalds { 6301da177e4SLinus Torvalds struct bio *n; 6311da177e4SLinus Torvalds 6321da177e4SLinus Torvalds while (bio) { 6331da177e4SLinus Torvalds n = bio->bi_next; 6341da177e4SLinus Torvalds bio->bi_next = NULL; 6351da177e4SLinus Torvalds bio_io_error(bio, bio->bi_size); 6361da177e4SLinus Torvalds bio = n; 6371da177e4SLinus Torvalds } 6381da177e4SLinus Torvalds } 6391da177e4SLinus Torvalds 640695368acSAlasdair G Kergon static void __invalidate_snapshot(struct dm_snapshot *s, int err) 64176df1c65SAlasdair G Kergon { 64276df1c65SAlasdair G Kergon if (!s->valid) 64376df1c65SAlasdair G Kergon return; 64476df1c65SAlasdair G Kergon 64576df1c65SAlasdair G Kergon if (err == -EIO) 64676df1c65SAlasdair G Kergon DMERR("Invalidating snapshot: Error reading/writing."); 64776df1c65SAlasdair G Kergon else if (err == -ENOMEM) 64876df1c65SAlasdair G Kergon DMERR("Invalidating snapshot: Unable to allocate exception."); 64976df1c65SAlasdair G Kergon 65076df1c65SAlasdair G Kergon if (s->store.drop_snapshot) 65176df1c65SAlasdair G Kergon s->store.drop_snapshot(&s->store); 65276df1c65SAlasdair G Kergon 65376df1c65SAlasdair G Kergon s->valid = 0; 65476df1c65SAlasdair G Kergon 65576df1c65SAlasdair G Kergon dm_table_event(s->table); 65676df1c65SAlasdair G Kergon } 65776df1c65SAlasdair G Kergon 6584b832e8dSAlasdair G Kergon static void get_pending_exception(struct pending_exception *pe) 6594b832e8dSAlasdair G Kergon { 6604b832e8dSAlasdair G Kergon atomic_inc(&pe->ref_count); 6614b832e8dSAlasdair G Kergon } 6624b832e8dSAlasdair G Kergon 6634b832e8dSAlasdair G Kergon static struct bio *put_pending_exception(struct pending_exception *pe) 6644b832e8dSAlasdair G Kergon { 6654b832e8dSAlasdair G Kergon struct pending_exception *primary_pe; 6664b832e8dSAlasdair G Kergon struct bio *origin_bios = NULL; 6674b832e8dSAlasdair G Kergon 6684b832e8dSAlasdair G Kergon primary_pe = pe->primary_pe; 6694b832e8dSAlasdair G Kergon 6704b832e8dSAlasdair G Kergon /* 6714b832e8dSAlasdair G Kergon * If this pe is involved in a write to the origin and 6724b832e8dSAlasdair G Kergon * it is the last sibling to complete then release 6734b832e8dSAlasdair G Kergon * the bios for the original write to the origin. 6744b832e8dSAlasdair G Kergon */ 6754b832e8dSAlasdair G Kergon if (primary_pe && 6764b832e8dSAlasdair G Kergon atomic_dec_and_test(&primary_pe->ref_count)) 6774b832e8dSAlasdair G Kergon origin_bios = bio_list_get(&primary_pe->origin_bios); 6784b832e8dSAlasdair G Kergon 6794b832e8dSAlasdair G Kergon /* 6804b832e8dSAlasdair G Kergon * Free the pe if it's not linked to an origin write or if 6814b832e8dSAlasdair G Kergon * it's not itself a primary pe. 6824b832e8dSAlasdair G Kergon */ 6834b832e8dSAlasdair G Kergon if (!primary_pe || primary_pe != pe) 6844b832e8dSAlasdair G Kergon free_pending_exception(pe); 6854b832e8dSAlasdair G Kergon 6864b832e8dSAlasdair G Kergon /* 6874b832e8dSAlasdair G Kergon * Free the primary pe if nothing references it. 6884b832e8dSAlasdair G Kergon */ 6894b832e8dSAlasdair G Kergon if (primary_pe && !atomic_read(&primary_pe->ref_count)) 6904b832e8dSAlasdair G Kergon free_pending_exception(primary_pe); 6914b832e8dSAlasdair G Kergon 6924b832e8dSAlasdair G Kergon return origin_bios; 6934b832e8dSAlasdair G Kergon } 6944b832e8dSAlasdair G Kergon 6951da177e4SLinus Torvalds static void pending_complete(struct pending_exception *pe, int success) 6961da177e4SLinus Torvalds { 6971da177e4SLinus Torvalds struct exception *e; 6981da177e4SLinus Torvalds struct dm_snapshot *s = pe->snap; 6999d493fa8SAlasdair G Kergon struct bio *origin_bios = NULL; 7009d493fa8SAlasdair G Kergon struct bio *snapshot_bios = NULL; 7019d493fa8SAlasdair G Kergon int error = 0; 7021da177e4SLinus Torvalds 70376df1c65SAlasdair G Kergon if (!success) { 70476df1c65SAlasdair G Kergon /* Read/write error - snapshot is unusable */ 7051da177e4SLinus Torvalds down_write(&s->lock); 706695368acSAlasdair G Kergon __invalidate_snapshot(s, -EIO); 7079d493fa8SAlasdair G Kergon error = 1; 70876df1c65SAlasdair G Kergon goto out; 70976df1c65SAlasdair G Kergon } 71076df1c65SAlasdair G Kergon 71176df1c65SAlasdair G Kergon e = alloc_exception(); 71276df1c65SAlasdair G Kergon if (!e) { 71376df1c65SAlasdair G Kergon down_write(&s->lock); 714695368acSAlasdair G Kergon __invalidate_snapshot(s, -ENOMEM); 7159d493fa8SAlasdair G Kergon error = 1; 7161da177e4SLinus Torvalds goto out; 7171da177e4SLinus Torvalds } 7181da177e4SLinus Torvalds *e = pe->e; 7191da177e4SLinus Torvalds 7209d493fa8SAlasdair G Kergon down_write(&s->lock); 7219d493fa8SAlasdair G Kergon if (!s->valid) { 7229d493fa8SAlasdair G Kergon free_exception(e); 7239d493fa8SAlasdair G Kergon error = 1; 7249d493fa8SAlasdair G Kergon goto out; 7259d493fa8SAlasdair G Kergon } 7269d493fa8SAlasdair G Kergon 7271da177e4SLinus Torvalds /* 7281da177e4SLinus Torvalds * Add a proper exception, and remove the 7291da177e4SLinus Torvalds * in-flight exception from the list. 7301da177e4SLinus Torvalds */ 7311da177e4SLinus Torvalds insert_exception(&s->complete, e); 7321da177e4SLinus Torvalds 7331da177e4SLinus Torvalds out: 734695368acSAlasdair G Kergon remove_exception(&pe->e); 7359d493fa8SAlasdair G Kergon snapshot_bios = bio_list_get(&pe->snapshot_bios); 7364b832e8dSAlasdair G Kergon origin_bios = put_pending_exception(pe); 737b4b610f6SAlasdair G Kergon 7389d493fa8SAlasdair G Kergon up_write(&s->lock); 7399d493fa8SAlasdair G Kergon 7409d493fa8SAlasdair G Kergon /* Submit any pending write bios */ 7419d493fa8SAlasdair G Kergon if (error) 7429d493fa8SAlasdair G Kergon error_bios(snapshot_bios); 7439d493fa8SAlasdair G Kergon else 7449d493fa8SAlasdair G Kergon flush_bios(snapshot_bios); 7459d493fa8SAlasdair G Kergon 7469d493fa8SAlasdair G Kergon flush_bios(origin_bios); 7471da177e4SLinus Torvalds } 7481da177e4SLinus Torvalds 7491da177e4SLinus Torvalds static void commit_callback(void *context, int success) 7501da177e4SLinus Torvalds { 7511da177e4SLinus Torvalds struct pending_exception *pe = (struct pending_exception *) context; 7521da177e4SLinus Torvalds pending_complete(pe, success); 7531da177e4SLinus Torvalds } 7541da177e4SLinus Torvalds 7551da177e4SLinus Torvalds /* 7561da177e4SLinus Torvalds * Called when the copy I/O has finished. kcopyd actually runs 7571da177e4SLinus Torvalds * this code so don't block. 7581da177e4SLinus Torvalds */ 7591da177e4SLinus Torvalds static void copy_callback(int read_err, unsigned int write_err, void *context) 7601da177e4SLinus Torvalds { 7611da177e4SLinus Torvalds struct pending_exception *pe = (struct pending_exception *) context; 7621da177e4SLinus Torvalds struct dm_snapshot *s = pe->snap; 7631da177e4SLinus Torvalds 7641da177e4SLinus Torvalds if (read_err || write_err) 7651da177e4SLinus Torvalds pending_complete(pe, 0); 7661da177e4SLinus Torvalds 7671da177e4SLinus Torvalds else 7681da177e4SLinus Torvalds /* Update the metadata if we are persistent */ 7691da177e4SLinus Torvalds s->store.commit_exception(&s->store, &pe->e, commit_callback, 7701da177e4SLinus Torvalds pe); 7711da177e4SLinus Torvalds } 7721da177e4SLinus Torvalds 7731da177e4SLinus Torvalds /* 7741da177e4SLinus Torvalds * Dispatches the copy operation to kcopyd. 7751da177e4SLinus Torvalds */ 776858119e1SArjan van de Ven static void start_copy(struct pending_exception *pe) 7771da177e4SLinus Torvalds { 7781da177e4SLinus Torvalds struct dm_snapshot *s = pe->snap; 7791da177e4SLinus Torvalds struct io_region src, dest; 7801da177e4SLinus Torvalds struct block_device *bdev = s->origin->bdev; 7811da177e4SLinus Torvalds sector_t dev_size; 7821da177e4SLinus Torvalds 7831da177e4SLinus Torvalds dev_size = get_dev_size(bdev); 7841da177e4SLinus Torvalds 7851da177e4SLinus Torvalds src.bdev = bdev; 7861da177e4SLinus Torvalds src.sector = chunk_to_sector(s, pe->e.old_chunk); 7871da177e4SLinus Torvalds src.count = min(s->chunk_size, dev_size - src.sector); 7881da177e4SLinus Torvalds 7891da177e4SLinus Torvalds dest.bdev = s->cow->bdev; 7901da177e4SLinus Torvalds dest.sector = chunk_to_sector(s, pe->e.new_chunk); 7911da177e4SLinus Torvalds dest.count = src.count; 7921da177e4SLinus Torvalds 7931da177e4SLinus Torvalds /* Hand over to kcopyd */ 7941da177e4SLinus Torvalds kcopyd_copy(s->kcopyd_client, 7951da177e4SLinus Torvalds &src, 1, &dest, 0, copy_callback, pe); 7961da177e4SLinus Torvalds } 7971da177e4SLinus Torvalds 7981da177e4SLinus Torvalds /* 7991da177e4SLinus Torvalds * Looks to see if this snapshot already has a pending exception 8001da177e4SLinus Torvalds * for this chunk, otherwise it allocates a new one and inserts 8011da177e4SLinus Torvalds * it into the pending table. 8021da177e4SLinus Torvalds * 8031da177e4SLinus Torvalds * NOTE: a write lock must be held on snap->lock before calling 8041da177e4SLinus Torvalds * this. 8051da177e4SLinus Torvalds */ 8061da177e4SLinus Torvalds static struct pending_exception * 8071da177e4SLinus Torvalds __find_pending_exception(struct dm_snapshot *s, struct bio *bio) 8081da177e4SLinus Torvalds { 8091da177e4SLinus Torvalds struct exception *e; 8101da177e4SLinus Torvalds struct pending_exception *pe; 8111da177e4SLinus Torvalds chunk_t chunk = sector_to_chunk(s, bio->bi_sector); 8121da177e4SLinus Torvalds 8131da177e4SLinus Torvalds /* 8141da177e4SLinus Torvalds * Is there a pending exception for this already ? 8151da177e4SLinus Torvalds */ 8161da177e4SLinus Torvalds e = lookup_exception(&s->pending, chunk); 8171da177e4SLinus Torvalds if (e) { 8181da177e4SLinus Torvalds /* cast the exception to a pending exception */ 8191da177e4SLinus Torvalds pe = container_of(e, struct pending_exception, e); 82076df1c65SAlasdair G Kergon goto out; 82176df1c65SAlasdair G Kergon } 8221da177e4SLinus Torvalds 8231da177e4SLinus Torvalds /* 8241da177e4SLinus Torvalds * Create a new pending exception, we don't want 8251da177e4SLinus Torvalds * to hold the lock while we do this. 8261da177e4SLinus Torvalds */ 8271da177e4SLinus Torvalds up_write(&s->lock); 8281da177e4SLinus Torvalds pe = alloc_pending_exception(); 8291da177e4SLinus Torvalds down_write(&s->lock); 8301da177e4SLinus Torvalds 83176df1c65SAlasdair G Kergon if (!s->valid) { 83276df1c65SAlasdair G Kergon free_pending_exception(pe); 83376df1c65SAlasdair G Kergon return NULL; 83476df1c65SAlasdair G Kergon } 83576df1c65SAlasdair G Kergon 8361da177e4SLinus Torvalds e = lookup_exception(&s->pending, chunk); 8371da177e4SLinus Torvalds if (e) { 8381da177e4SLinus Torvalds free_pending_exception(pe); 8391da177e4SLinus Torvalds pe = container_of(e, struct pending_exception, e); 84076df1c65SAlasdair G Kergon goto out; 84176df1c65SAlasdair G Kergon } 84276df1c65SAlasdair G Kergon 8431da177e4SLinus Torvalds pe->e.old_chunk = chunk; 8441da177e4SLinus Torvalds bio_list_init(&pe->origin_bios); 8451da177e4SLinus Torvalds bio_list_init(&pe->snapshot_bios); 846b4b610f6SAlasdair G Kergon pe->primary_pe = NULL; 8474b832e8dSAlasdair G Kergon atomic_set(&pe->ref_count, 0); 8481da177e4SLinus Torvalds pe->snap = s; 8491da177e4SLinus Torvalds pe->started = 0; 8501da177e4SLinus Torvalds 8511da177e4SLinus Torvalds if (s->store.prepare_exception(&s->store, &pe->e)) { 8521da177e4SLinus Torvalds free_pending_exception(pe); 8531da177e4SLinus Torvalds return NULL; 8541da177e4SLinus Torvalds } 8551da177e4SLinus Torvalds 8564b832e8dSAlasdair G Kergon get_pending_exception(pe); 8571da177e4SLinus Torvalds insert_exception(&s->pending, &pe->e); 8581da177e4SLinus Torvalds 85976df1c65SAlasdair G Kergon out: 8601da177e4SLinus Torvalds return pe; 8611da177e4SLinus Torvalds } 8621da177e4SLinus Torvalds 8631da177e4SLinus Torvalds static inline void remap_exception(struct dm_snapshot *s, struct exception *e, 8641da177e4SLinus Torvalds struct bio *bio) 8651da177e4SLinus Torvalds { 8661da177e4SLinus Torvalds bio->bi_bdev = s->cow->bdev; 8671da177e4SLinus Torvalds bio->bi_sector = chunk_to_sector(s, e->new_chunk) + 8681da177e4SLinus Torvalds (bio->bi_sector & s->chunk_mask); 8691da177e4SLinus Torvalds } 8701da177e4SLinus Torvalds 8711da177e4SLinus Torvalds static int snapshot_map(struct dm_target *ti, struct bio *bio, 8721da177e4SLinus Torvalds union map_info *map_context) 8731da177e4SLinus Torvalds { 8741da177e4SLinus Torvalds struct exception *e; 8751da177e4SLinus Torvalds struct dm_snapshot *s = (struct dm_snapshot *) ti->private; 876d2a7ad29SKiyoshi Ueda int r = DM_MAPIO_REMAPPED; 8771da177e4SLinus Torvalds chunk_t chunk; 87876df1c65SAlasdair G Kergon struct pending_exception *pe = NULL; 8791da177e4SLinus Torvalds 8801da177e4SLinus Torvalds chunk = sector_to_chunk(s, bio->bi_sector); 8811da177e4SLinus Torvalds 8821da177e4SLinus Torvalds /* Full snapshots are not usable */ 88376df1c65SAlasdair G Kergon /* To get here the table must be live so s->active is always set. */ 8841da177e4SLinus Torvalds if (!s->valid) 885f6a80ea8SAlasdair G Kergon return -EIO; 8861da177e4SLinus Torvalds 8874aac0a63SAlasdair G Kergon if (unlikely(bio_barrier(bio))) 8884aac0a63SAlasdair G Kergon return -EOPNOTSUPP; 8894aac0a63SAlasdair G Kergon 8901da177e4SLinus Torvalds /* FIXME: should only take write lock if we need 8911da177e4SLinus Torvalds * to copy an exception */ 8921da177e4SLinus Torvalds down_write(&s->lock); 8931da177e4SLinus Torvalds 89476df1c65SAlasdair G Kergon if (!s->valid) { 89576df1c65SAlasdair G Kergon r = -EIO; 89676df1c65SAlasdair G Kergon goto out_unlock; 89776df1c65SAlasdair G Kergon } 89876df1c65SAlasdair G Kergon 8991da177e4SLinus Torvalds /* If the block is already remapped - use that, else remap it */ 9001da177e4SLinus Torvalds e = lookup_exception(&s->complete, chunk); 9011da177e4SLinus Torvalds if (e) { 9021da177e4SLinus Torvalds remap_exception(s, e, bio); 90376df1c65SAlasdair G Kergon goto out_unlock; 90476df1c65SAlasdair G Kergon } 9051da177e4SLinus Torvalds 906ba40a2aaSAlasdair G Kergon /* 907ba40a2aaSAlasdair G Kergon * Write to snapshot - higher level takes care of RW/RO 908ba40a2aaSAlasdair G Kergon * flags so we should only get this if we are 909ba40a2aaSAlasdair G Kergon * writeable. 910ba40a2aaSAlasdair G Kergon */ 911ba40a2aaSAlasdair G Kergon if (bio_rw(bio) == WRITE) { 9121da177e4SLinus Torvalds pe = __find_pending_exception(s, bio); 9131da177e4SLinus Torvalds if (!pe) { 914695368acSAlasdair G Kergon __invalidate_snapshot(s, -ENOMEM); 9151da177e4SLinus Torvalds r = -EIO; 91676df1c65SAlasdair G Kergon goto out_unlock; 91776df1c65SAlasdair G Kergon } 91876df1c65SAlasdair G Kergon 9191da177e4SLinus Torvalds remap_exception(s, &pe->e, bio); 9201da177e4SLinus Torvalds bio_list_add(&pe->snapshot_bios, bio); 9211da177e4SLinus Torvalds 922d2a7ad29SKiyoshi Ueda r = DM_MAPIO_SUBMITTED; 923ba40a2aaSAlasdair G Kergon 9241da177e4SLinus Torvalds if (!pe->started) { 9251da177e4SLinus Torvalds /* this is protected by snap->lock */ 9261da177e4SLinus Torvalds pe->started = 1; 92776df1c65SAlasdair G Kergon up_write(&s->lock); 92876df1c65SAlasdair G Kergon start_copy(pe); 929ba40a2aaSAlasdair G Kergon goto out; 930ba40a2aaSAlasdair G Kergon } 931ba40a2aaSAlasdair G Kergon } else 9321da177e4SLinus Torvalds /* 9331da177e4SLinus Torvalds * FIXME: this read path scares me because we 9341da177e4SLinus Torvalds * always use the origin when we have a pending 9351da177e4SLinus Torvalds * exception. However I can't think of a 9361da177e4SLinus Torvalds * situation where this is wrong - ejt. 9371da177e4SLinus Torvalds */ 9381da177e4SLinus Torvalds bio->bi_bdev = s->origin->bdev; 9391da177e4SLinus Torvalds 940ba40a2aaSAlasdair G Kergon out_unlock: 941ba40a2aaSAlasdair G Kergon up_write(&s->lock); 942ba40a2aaSAlasdair G Kergon out: 9431da177e4SLinus Torvalds return r; 9441da177e4SLinus Torvalds } 9451da177e4SLinus Torvalds 9461da177e4SLinus Torvalds static void snapshot_resume(struct dm_target *ti) 9471da177e4SLinus Torvalds { 9481da177e4SLinus Torvalds struct dm_snapshot *s = (struct dm_snapshot *) ti->private; 9491da177e4SLinus Torvalds 950aa14edebSAlasdair G Kergon down_write(&s->lock); 951aa14edebSAlasdair G Kergon s->active = 1; 952aa14edebSAlasdair G Kergon up_write(&s->lock); 9531da177e4SLinus Torvalds } 9541da177e4SLinus Torvalds 9551da177e4SLinus Torvalds static int snapshot_status(struct dm_target *ti, status_type_t type, 9561da177e4SLinus Torvalds char *result, unsigned int maxlen) 9571da177e4SLinus Torvalds { 9581da177e4SLinus Torvalds struct dm_snapshot *snap = (struct dm_snapshot *) ti->private; 9591da177e4SLinus Torvalds 9601da177e4SLinus Torvalds switch (type) { 9611da177e4SLinus Torvalds case STATUSTYPE_INFO: 9621da177e4SLinus Torvalds if (!snap->valid) 9631da177e4SLinus Torvalds snprintf(result, maxlen, "Invalid"); 9641da177e4SLinus Torvalds else { 9651da177e4SLinus Torvalds if (snap->store.fraction_full) { 9661da177e4SLinus Torvalds sector_t numerator, denominator; 9671da177e4SLinus Torvalds snap->store.fraction_full(&snap->store, 9681da177e4SLinus Torvalds &numerator, 9691da177e4SLinus Torvalds &denominator); 9704ee218cdSAndrew Morton snprintf(result, maxlen, "%llu/%llu", 9714ee218cdSAndrew Morton (unsigned long long)numerator, 9724ee218cdSAndrew Morton (unsigned long long)denominator); 9731da177e4SLinus Torvalds } 9741da177e4SLinus Torvalds else 9751da177e4SLinus Torvalds snprintf(result, maxlen, "Unknown"); 9761da177e4SLinus Torvalds } 9771da177e4SLinus Torvalds break; 9781da177e4SLinus Torvalds 9791da177e4SLinus Torvalds case STATUSTYPE_TABLE: 9801da177e4SLinus Torvalds /* 9811da177e4SLinus Torvalds * kdevname returns a static pointer so we need 9821da177e4SLinus Torvalds * to make private copies if the output is to 9831da177e4SLinus Torvalds * make sense. 9841da177e4SLinus Torvalds */ 9854ee218cdSAndrew Morton snprintf(result, maxlen, "%s %s %c %llu", 9861da177e4SLinus Torvalds snap->origin->name, snap->cow->name, 9874ee218cdSAndrew Morton snap->type, 9884ee218cdSAndrew Morton (unsigned long long)snap->chunk_size); 9891da177e4SLinus Torvalds break; 9901da177e4SLinus Torvalds } 9911da177e4SLinus Torvalds 9921da177e4SLinus Torvalds return 0; 9931da177e4SLinus Torvalds } 9941da177e4SLinus Torvalds 9951da177e4SLinus Torvalds /*----------------------------------------------------------------- 9961da177e4SLinus Torvalds * Origin methods 9971da177e4SLinus Torvalds *---------------------------------------------------------------*/ 9981da177e4SLinus Torvalds static int __origin_write(struct list_head *snapshots, struct bio *bio) 9991da177e4SLinus Torvalds { 1000d2a7ad29SKiyoshi Ueda int r = DM_MAPIO_REMAPPED, first = 0; 10011da177e4SLinus Torvalds struct dm_snapshot *snap; 10021da177e4SLinus Torvalds struct exception *e; 1003b4b610f6SAlasdair G Kergon struct pending_exception *pe, *next_pe, *primary_pe = NULL; 10041da177e4SLinus Torvalds chunk_t chunk; 1005eccf0817SAlasdair G Kergon LIST_HEAD(pe_queue); 10061da177e4SLinus Torvalds 10071da177e4SLinus Torvalds /* Do all the snapshots on this origin */ 10081da177e4SLinus Torvalds list_for_each_entry (snap, snapshots, list) { 10091da177e4SLinus Torvalds 101076df1c65SAlasdair G Kergon down_write(&snap->lock); 101176df1c65SAlasdair G Kergon 1012aa14edebSAlasdair G Kergon /* Only deal with valid and active snapshots */ 1013aa14edebSAlasdair G Kergon if (!snap->valid || !snap->active) 101476df1c65SAlasdair G Kergon goto next_snapshot; 10151da177e4SLinus Torvalds 1016d5e404c1SAlasdair G Kergon /* Nothing to do if writing beyond end of snapshot */ 1017d5e404c1SAlasdair G Kergon if (bio->bi_sector >= dm_table_get_size(snap->table)) 101876df1c65SAlasdair G Kergon goto next_snapshot; 10191da177e4SLinus Torvalds 10201da177e4SLinus Torvalds /* 10211da177e4SLinus Torvalds * Remember, different snapshots can have 10221da177e4SLinus Torvalds * different chunk sizes. 10231da177e4SLinus Torvalds */ 10241da177e4SLinus Torvalds chunk = sector_to_chunk(snap, bio->bi_sector); 10251da177e4SLinus Torvalds 10261da177e4SLinus Torvalds /* 10271da177e4SLinus Torvalds * Check exception table to see if block 10281da177e4SLinus Torvalds * is already remapped in this snapshot 10291da177e4SLinus Torvalds * and trigger an exception if not. 1030b4b610f6SAlasdair G Kergon * 10314b832e8dSAlasdair G Kergon * ref_count is initialised to 1 so pending_complete() 1032b4b610f6SAlasdair G Kergon * won't destroy the primary_pe while we're inside this loop. 10331da177e4SLinus Torvalds */ 10341da177e4SLinus Torvalds e = lookup_exception(&snap->complete, chunk); 103576df1c65SAlasdair G Kergon if (e) 103676df1c65SAlasdair G Kergon goto next_snapshot; 103776df1c65SAlasdair G Kergon 10381da177e4SLinus Torvalds pe = __find_pending_exception(snap, bio); 10391da177e4SLinus Torvalds if (!pe) { 1040695368acSAlasdair G Kergon __invalidate_snapshot(snap, -ENOMEM); 104176df1c65SAlasdair G Kergon goto next_snapshot; 104276df1c65SAlasdair G Kergon } 10431da177e4SLinus Torvalds 1044b4b610f6SAlasdair G Kergon if (!primary_pe) { 1045b4b610f6SAlasdair G Kergon /* 1046b4b610f6SAlasdair G Kergon * Either every pe here has same 1047b4b610f6SAlasdair G Kergon * primary_pe or none has one yet. 1048b4b610f6SAlasdair G Kergon */ 1049b4b610f6SAlasdair G Kergon if (pe->primary_pe) 1050b4b610f6SAlasdair G Kergon primary_pe = pe->primary_pe; 1051b4b610f6SAlasdair G Kergon else { 1052b4b610f6SAlasdair G Kergon primary_pe = pe; 1053b4b610f6SAlasdair G Kergon first = 1; 1054eccf0817SAlasdair G Kergon } 1055b4b610f6SAlasdair G Kergon 105676df1c65SAlasdair G Kergon bio_list_add(&primary_pe->origin_bios, bio); 105776df1c65SAlasdair G Kergon 1058d2a7ad29SKiyoshi Ueda r = DM_MAPIO_SUBMITTED; 1059b4b610f6SAlasdair G Kergon } 106076df1c65SAlasdair G Kergon 1061b4b610f6SAlasdair G Kergon if (!pe->primary_pe) { 1062b4b610f6SAlasdair G Kergon pe->primary_pe = primary_pe; 10634b832e8dSAlasdair G Kergon get_pending_exception(primary_pe); 1064b4b610f6SAlasdair G Kergon } 106576df1c65SAlasdair G Kergon 1066eccf0817SAlasdair G Kergon if (!pe->started) { 1067eccf0817SAlasdair G Kergon pe->started = 1; 1068eccf0817SAlasdair G Kergon list_add_tail(&pe->list, &pe_queue); 1069eccf0817SAlasdair G Kergon } 10701da177e4SLinus Torvalds 107176df1c65SAlasdair G Kergon next_snapshot: 10721da177e4SLinus Torvalds up_write(&snap->lock); 10731da177e4SLinus Torvalds } 10741da177e4SLinus Torvalds 1075b4b610f6SAlasdair G Kergon if (!primary_pe) 10764b832e8dSAlasdair G Kergon return r; 1077b4b610f6SAlasdair G Kergon 1078b4b610f6SAlasdair G Kergon /* 1079b4b610f6SAlasdair G Kergon * If this is the first time we're processing this chunk and 10804b832e8dSAlasdair G Kergon * ref_count is now 1 it means all the pending exceptions 1081b4b610f6SAlasdair G Kergon * got completed while we were in the loop above, so it falls to 1082b4b610f6SAlasdair G Kergon * us here to remove the primary_pe and submit any origin_bios. 1083b4b610f6SAlasdair G Kergon */ 1084b4b610f6SAlasdair G Kergon 10854b832e8dSAlasdair G Kergon if (first && atomic_dec_and_test(&primary_pe->ref_count)) { 1086b4b610f6SAlasdair G Kergon flush_bios(bio_list_get(&primary_pe->origin_bios)); 1087b4b610f6SAlasdair G Kergon free_pending_exception(primary_pe); 1088b4b610f6SAlasdair G Kergon /* If we got here, pe_queue is necessarily empty. */ 10894b832e8dSAlasdair G Kergon return r; 1090b4b610f6SAlasdair G Kergon } 1091b4b610f6SAlasdair G Kergon 10921da177e4SLinus Torvalds /* 10931da177e4SLinus Torvalds * Now that we have a complete pe list we can start the copying. 10941da177e4SLinus Torvalds */ 1095eccf0817SAlasdair G Kergon list_for_each_entry_safe(pe, next_pe, &pe_queue, list) 10961da177e4SLinus Torvalds start_copy(pe); 10971da177e4SLinus Torvalds 10981da177e4SLinus Torvalds return r; 10991da177e4SLinus Torvalds } 11001da177e4SLinus Torvalds 11011da177e4SLinus Torvalds /* 11021da177e4SLinus Torvalds * Called on a write from the origin driver. 11031da177e4SLinus Torvalds */ 11041da177e4SLinus Torvalds static int do_origin(struct dm_dev *origin, struct bio *bio) 11051da177e4SLinus Torvalds { 11061da177e4SLinus Torvalds struct origin *o; 1107d2a7ad29SKiyoshi Ueda int r = DM_MAPIO_REMAPPED; 11081da177e4SLinus Torvalds 11091da177e4SLinus Torvalds down_read(&_origins_lock); 11101da177e4SLinus Torvalds o = __lookup_origin(origin->bdev); 11111da177e4SLinus Torvalds if (o) 11121da177e4SLinus Torvalds r = __origin_write(&o->snapshots, bio); 11131da177e4SLinus Torvalds up_read(&_origins_lock); 11141da177e4SLinus Torvalds 11151da177e4SLinus Torvalds return r; 11161da177e4SLinus Torvalds } 11171da177e4SLinus Torvalds 11181da177e4SLinus Torvalds /* 11191da177e4SLinus Torvalds * Origin: maps a linear range of a device, with hooks for snapshotting. 11201da177e4SLinus Torvalds */ 11211da177e4SLinus Torvalds 11221da177e4SLinus Torvalds /* 11231da177e4SLinus Torvalds * Construct an origin mapping: <dev_path> 11241da177e4SLinus Torvalds * The context for an origin is merely a 'struct dm_dev *' 11251da177e4SLinus Torvalds * pointing to the real device. 11261da177e4SLinus Torvalds */ 11271da177e4SLinus Torvalds static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv) 11281da177e4SLinus Torvalds { 11291da177e4SLinus Torvalds int r; 11301da177e4SLinus Torvalds struct dm_dev *dev; 11311da177e4SLinus Torvalds 11321da177e4SLinus Torvalds if (argc != 1) { 113372d94861SAlasdair G Kergon ti->error = "origin: incorrect number of arguments"; 11341da177e4SLinus Torvalds return -EINVAL; 11351da177e4SLinus Torvalds } 11361da177e4SLinus Torvalds 11371da177e4SLinus Torvalds r = dm_get_device(ti, argv[0], 0, ti->len, 11381da177e4SLinus Torvalds dm_table_get_mode(ti->table), &dev); 11391da177e4SLinus Torvalds if (r) { 11401da177e4SLinus Torvalds ti->error = "Cannot get target device"; 11411da177e4SLinus Torvalds return r; 11421da177e4SLinus Torvalds } 11431da177e4SLinus Torvalds 11441da177e4SLinus Torvalds ti->private = dev; 11451da177e4SLinus Torvalds return 0; 11461da177e4SLinus Torvalds } 11471da177e4SLinus Torvalds 11481da177e4SLinus Torvalds static void origin_dtr(struct dm_target *ti) 11491da177e4SLinus Torvalds { 11501da177e4SLinus Torvalds struct dm_dev *dev = (struct dm_dev *) ti->private; 11511da177e4SLinus Torvalds dm_put_device(ti, dev); 11521da177e4SLinus Torvalds } 11531da177e4SLinus Torvalds 11541da177e4SLinus Torvalds static int origin_map(struct dm_target *ti, struct bio *bio, 11551da177e4SLinus Torvalds union map_info *map_context) 11561da177e4SLinus Torvalds { 11571da177e4SLinus Torvalds struct dm_dev *dev = (struct dm_dev *) ti->private; 11581da177e4SLinus Torvalds bio->bi_bdev = dev->bdev; 11591da177e4SLinus Torvalds 11604aac0a63SAlasdair G Kergon if (unlikely(bio_barrier(bio))) 11614aac0a63SAlasdair G Kergon return -EOPNOTSUPP; 11624aac0a63SAlasdair G Kergon 11631da177e4SLinus Torvalds /* Only tell snapshots if this is a write */ 1164d2a7ad29SKiyoshi Ueda return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED; 11651da177e4SLinus Torvalds } 11661da177e4SLinus Torvalds 11671da177e4SLinus Torvalds #define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r)) 11681da177e4SLinus Torvalds 11691da177e4SLinus Torvalds /* 11701da177e4SLinus Torvalds * Set the target "split_io" field to the minimum of all the snapshots' 11711da177e4SLinus Torvalds * chunk sizes. 11721da177e4SLinus Torvalds */ 11731da177e4SLinus Torvalds static void origin_resume(struct dm_target *ti) 11741da177e4SLinus Torvalds { 11751da177e4SLinus Torvalds struct dm_dev *dev = (struct dm_dev *) ti->private; 11761da177e4SLinus Torvalds struct dm_snapshot *snap; 11771da177e4SLinus Torvalds struct origin *o; 11781da177e4SLinus Torvalds chunk_t chunk_size = 0; 11791da177e4SLinus Torvalds 11801da177e4SLinus Torvalds down_read(&_origins_lock); 11811da177e4SLinus Torvalds o = __lookup_origin(dev->bdev); 11821da177e4SLinus Torvalds if (o) 11831da177e4SLinus Torvalds list_for_each_entry (snap, &o->snapshots, list) 11841da177e4SLinus Torvalds chunk_size = min_not_zero(chunk_size, snap->chunk_size); 11851da177e4SLinus Torvalds up_read(&_origins_lock); 11861da177e4SLinus Torvalds 11871da177e4SLinus Torvalds ti->split_io = chunk_size; 11881da177e4SLinus Torvalds } 11891da177e4SLinus Torvalds 11901da177e4SLinus Torvalds static int origin_status(struct dm_target *ti, status_type_t type, char *result, 11911da177e4SLinus Torvalds unsigned int maxlen) 11921da177e4SLinus Torvalds { 11931da177e4SLinus Torvalds struct dm_dev *dev = (struct dm_dev *) ti->private; 11941da177e4SLinus Torvalds 11951da177e4SLinus Torvalds switch (type) { 11961da177e4SLinus Torvalds case STATUSTYPE_INFO: 11971da177e4SLinus Torvalds result[0] = '\0'; 11981da177e4SLinus Torvalds break; 11991da177e4SLinus Torvalds 12001da177e4SLinus Torvalds case STATUSTYPE_TABLE: 12011da177e4SLinus Torvalds snprintf(result, maxlen, "%s", dev->name); 12021da177e4SLinus Torvalds break; 12031da177e4SLinus Torvalds } 12041da177e4SLinus Torvalds 12051da177e4SLinus Torvalds return 0; 12061da177e4SLinus Torvalds } 12071da177e4SLinus Torvalds 12081da177e4SLinus Torvalds static struct target_type origin_target = { 12091da177e4SLinus Torvalds .name = "snapshot-origin", 12104c7e3bf4SMark McLoughlin .version = {1, 5, 0}, 12111da177e4SLinus Torvalds .module = THIS_MODULE, 12121da177e4SLinus Torvalds .ctr = origin_ctr, 12131da177e4SLinus Torvalds .dtr = origin_dtr, 12141da177e4SLinus Torvalds .map = origin_map, 12151da177e4SLinus Torvalds .resume = origin_resume, 12161da177e4SLinus Torvalds .status = origin_status, 12171da177e4SLinus Torvalds }; 12181da177e4SLinus Torvalds 12191da177e4SLinus Torvalds static struct target_type snapshot_target = { 12201da177e4SLinus Torvalds .name = "snapshot", 12214c7e3bf4SMark McLoughlin .version = {1, 5, 0}, 12221da177e4SLinus Torvalds .module = THIS_MODULE, 12231da177e4SLinus Torvalds .ctr = snapshot_ctr, 12241da177e4SLinus Torvalds .dtr = snapshot_dtr, 12251da177e4SLinus Torvalds .map = snapshot_map, 12261da177e4SLinus Torvalds .resume = snapshot_resume, 12271da177e4SLinus Torvalds .status = snapshot_status, 12281da177e4SLinus Torvalds }; 12291da177e4SLinus Torvalds 12301da177e4SLinus Torvalds static int __init dm_snapshot_init(void) 12311da177e4SLinus Torvalds { 12321da177e4SLinus Torvalds int r; 12331da177e4SLinus Torvalds 12341da177e4SLinus Torvalds r = dm_register_target(&snapshot_target); 12351da177e4SLinus Torvalds if (r) { 12361da177e4SLinus Torvalds DMERR("snapshot target register failed %d", r); 12371da177e4SLinus Torvalds return r; 12381da177e4SLinus Torvalds } 12391da177e4SLinus Torvalds 12401da177e4SLinus Torvalds r = dm_register_target(&origin_target); 12411da177e4SLinus Torvalds if (r < 0) { 124272d94861SAlasdair G Kergon DMERR("Origin target register failed %d", r); 12431da177e4SLinus Torvalds goto bad1; 12441da177e4SLinus Torvalds } 12451da177e4SLinus Torvalds 12461da177e4SLinus Torvalds r = init_origin_hash(); 12471da177e4SLinus Torvalds if (r) { 12481da177e4SLinus Torvalds DMERR("init_origin_hash failed."); 12491da177e4SLinus Torvalds goto bad2; 12501da177e4SLinus Torvalds } 12511da177e4SLinus Torvalds 12521da177e4SLinus Torvalds exception_cache = kmem_cache_create("dm-snapshot-ex", 12531da177e4SLinus Torvalds sizeof(struct exception), 12541da177e4SLinus Torvalds __alignof__(struct exception), 12551da177e4SLinus Torvalds 0, NULL, NULL); 12561da177e4SLinus Torvalds if (!exception_cache) { 12571da177e4SLinus Torvalds DMERR("Couldn't create exception cache."); 12581da177e4SLinus Torvalds r = -ENOMEM; 12591da177e4SLinus Torvalds goto bad3; 12601da177e4SLinus Torvalds } 12611da177e4SLinus Torvalds 12621da177e4SLinus Torvalds pending_cache = 12631da177e4SLinus Torvalds kmem_cache_create("dm-snapshot-in", 12641da177e4SLinus Torvalds sizeof(struct pending_exception), 12651da177e4SLinus Torvalds __alignof__(struct pending_exception), 12661da177e4SLinus Torvalds 0, NULL, NULL); 12671da177e4SLinus Torvalds if (!pending_cache) { 12681da177e4SLinus Torvalds DMERR("Couldn't create pending cache."); 12691da177e4SLinus Torvalds r = -ENOMEM; 12701da177e4SLinus Torvalds goto bad4; 12711da177e4SLinus Torvalds } 12721da177e4SLinus Torvalds 127393d2341cSMatthew Dobson pending_pool = mempool_create_slab_pool(128, pending_cache); 12741da177e4SLinus Torvalds if (!pending_pool) { 12751da177e4SLinus Torvalds DMERR("Couldn't create pending pool."); 12761da177e4SLinus Torvalds r = -ENOMEM; 12771da177e4SLinus Torvalds goto bad5; 12781da177e4SLinus Torvalds } 12791da177e4SLinus Torvalds 1280ca3a931fSAlasdair G Kergon ksnapd = create_singlethread_workqueue("ksnapd"); 1281ca3a931fSAlasdair G Kergon if (!ksnapd) { 1282ca3a931fSAlasdair G Kergon DMERR("Failed to create ksnapd workqueue."); 1283ca3a931fSAlasdair G Kergon r = -ENOMEM; 1284ca3a931fSAlasdair G Kergon goto bad6; 1285ca3a931fSAlasdair G Kergon } 1286ca3a931fSAlasdair G Kergon 12871da177e4SLinus Torvalds return 0; 12881da177e4SLinus Torvalds 1289ca3a931fSAlasdair G Kergon bad6: 1290ca3a931fSAlasdair G Kergon mempool_destroy(pending_pool); 12911da177e4SLinus Torvalds bad5: 12921da177e4SLinus Torvalds kmem_cache_destroy(pending_cache); 12931da177e4SLinus Torvalds bad4: 12941da177e4SLinus Torvalds kmem_cache_destroy(exception_cache); 12951da177e4SLinus Torvalds bad3: 12961da177e4SLinus Torvalds exit_origin_hash(); 12971da177e4SLinus Torvalds bad2: 12981da177e4SLinus Torvalds dm_unregister_target(&origin_target); 12991da177e4SLinus Torvalds bad1: 13001da177e4SLinus Torvalds dm_unregister_target(&snapshot_target); 13011da177e4SLinus Torvalds return r; 13021da177e4SLinus Torvalds } 13031da177e4SLinus Torvalds 13041da177e4SLinus Torvalds static void __exit dm_snapshot_exit(void) 13051da177e4SLinus Torvalds { 13061da177e4SLinus Torvalds int r; 13071da177e4SLinus Torvalds 1308ca3a931fSAlasdair G Kergon destroy_workqueue(ksnapd); 1309ca3a931fSAlasdair G Kergon 13101da177e4SLinus Torvalds r = dm_unregister_target(&snapshot_target); 13111da177e4SLinus Torvalds if (r) 13121da177e4SLinus Torvalds DMERR("snapshot unregister failed %d", r); 13131da177e4SLinus Torvalds 13141da177e4SLinus Torvalds r = dm_unregister_target(&origin_target); 13151da177e4SLinus Torvalds if (r) 13161da177e4SLinus Torvalds DMERR("origin unregister failed %d", r); 13171da177e4SLinus Torvalds 13181da177e4SLinus Torvalds exit_origin_hash(); 13191da177e4SLinus Torvalds mempool_destroy(pending_pool); 13201da177e4SLinus Torvalds kmem_cache_destroy(pending_cache); 13211da177e4SLinus Torvalds kmem_cache_destroy(exception_cache); 13221da177e4SLinus Torvalds } 13231da177e4SLinus Torvalds 13241da177e4SLinus Torvalds /* Module hooks */ 13251da177e4SLinus Torvalds module_init(dm_snapshot_init); 13261da177e4SLinus Torvalds module_exit(dm_snapshot_exit); 13271da177e4SLinus Torvalds 13281da177e4SLinus Torvalds MODULE_DESCRIPTION(DM_NAME " snapshot target"); 13291da177e4SLinus Torvalds MODULE_AUTHOR("Joe Thornber"); 13301da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 1331