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> 206f3c3f0aSvignesh babu #include <linux/log2.h> 211da177e4SLinus Torvalds 221da177e4SLinus Torvalds #include "dm-snap.h" 231da177e4SLinus Torvalds #include "dm-bio-list.h" 241da177e4SLinus Torvalds #include "kcopyd.h" 251da177e4SLinus Torvalds 2672d94861SAlasdair G Kergon #define DM_MSG_PREFIX "snapshots" 2772d94861SAlasdair G Kergon 281da177e4SLinus Torvalds /* 291da177e4SLinus Torvalds * The percentage increment we will wake up users at 301da177e4SLinus Torvalds */ 311da177e4SLinus Torvalds #define WAKE_UP_PERCENT 5 321da177e4SLinus Torvalds 331da177e4SLinus Torvalds /* 341da177e4SLinus Torvalds * kcopyd priority of snapshot operations 351da177e4SLinus Torvalds */ 361da177e4SLinus Torvalds #define SNAPSHOT_COPY_PRIORITY 2 371da177e4SLinus Torvalds 381da177e4SLinus Torvalds /* 391da177e4SLinus Torvalds * Each snapshot reserves this many pages for io 401da177e4SLinus Torvalds */ 411da177e4SLinus Torvalds #define SNAPSHOT_PAGES 256 421da177e4SLinus Torvalds 43c642f9e0SAdrian Bunk static struct workqueue_struct *ksnapd; 44c4028958SDavid Howells static void flush_queued_bios(struct work_struct *work); 45ca3a931fSAlasdair G Kergon 46028867acSAlasdair G Kergon struct dm_snap_pending_exception { 47028867acSAlasdair G Kergon struct dm_snap_exception e; 481da177e4SLinus Torvalds 491da177e4SLinus Torvalds /* 501da177e4SLinus Torvalds * Origin buffers waiting for this to complete are held 511da177e4SLinus Torvalds * in a bio list 521da177e4SLinus Torvalds */ 531da177e4SLinus Torvalds struct bio_list origin_bios; 541da177e4SLinus Torvalds struct bio_list snapshot_bios; 551da177e4SLinus Torvalds 561da177e4SLinus Torvalds /* 57eccf0817SAlasdair G Kergon * Short-term queue of pending exceptions prior to submission. 58eccf0817SAlasdair G Kergon */ 59eccf0817SAlasdair G Kergon struct list_head list; 60eccf0817SAlasdair G Kergon 61eccf0817SAlasdair G Kergon /* 62b4b610f6SAlasdair G Kergon * The primary pending_exception is the one that holds 634b832e8dSAlasdair G Kergon * the ref_count and the list of origin_bios for a 64b4b610f6SAlasdair G Kergon * group of pending_exceptions. It is always last to get freed. 65b4b610f6SAlasdair G Kergon * These fields get set up when writing to the origin. 661da177e4SLinus Torvalds */ 67028867acSAlasdair G Kergon struct dm_snap_pending_exception *primary_pe; 68b4b610f6SAlasdair G Kergon 69b4b610f6SAlasdair G Kergon /* 70b4b610f6SAlasdair G Kergon * Number of pending_exceptions processing this chunk. 71b4b610f6SAlasdair G Kergon * When this drops to zero we must complete the origin bios. 72b4b610f6SAlasdair G Kergon * If incrementing or decrementing this, hold pe->snap->lock for 73b4b610f6SAlasdair G Kergon * the sibling concerned and not pe->primary_pe->snap->lock unless 74b4b610f6SAlasdair G Kergon * they are the same. 75b4b610f6SAlasdair G Kergon */ 764b832e8dSAlasdair G Kergon atomic_t ref_count; 771da177e4SLinus Torvalds 781da177e4SLinus Torvalds /* Pointer back to snapshot context */ 791da177e4SLinus Torvalds struct dm_snapshot *snap; 801da177e4SLinus Torvalds 811da177e4SLinus Torvalds /* 821da177e4SLinus Torvalds * 1 indicates the exception has already been sent to 831da177e4SLinus Torvalds * kcopyd. 841da177e4SLinus Torvalds */ 851da177e4SLinus Torvalds int started; 861da177e4SLinus Torvalds }; 871da177e4SLinus Torvalds 881da177e4SLinus Torvalds /* 891da177e4SLinus Torvalds * Hash table mapping origin volumes to lists of snapshots and 901da177e4SLinus Torvalds * a lock to protect it 911da177e4SLinus Torvalds */ 92e18b890bSChristoph Lameter static struct kmem_cache *exception_cache; 93e18b890bSChristoph Lameter static struct kmem_cache *pending_cache; 941da177e4SLinus Torvalds static mempool_t *pending_pool; 951da177e4SLinus Torvalds 961da177e4SLinus Torvalds /* 971da177e4SLinus Torvalds * One of these per registered origin, held in the snapshot_origins hash 981da177e4SLinus Torvalds */ 991da177e4SLinus Torvalds struct origin { 1001da177e4SLinus Torvalds /* The origin device */ 1011da177e4SLinus Torvalds struct block_device *bdev; 1021da177e4SLinus Torvalds 1031da177e4SLinus Torvalds struct list_head hash_list; 1041da177e4SLinus Torvalds 1051da177e4SLinus Torvalds /* List of snapshots for this origin */ 1061da177e4SLinus Torvalds struct list_head snapshots; 1071da177e4SLinus Torvalds }; 1081da177e4SLinus Torvalds 1091da177e4SLinus Torvalds /* 1101da177e4SLinus Torvalds * Size of the hash table for origin volumes. If we make this 1111da177e4SLinus Torvalds * the size of the minors list then it should be nearly perfect 1121da177e4SLinus Torvalds */ 1131da177e4SLinus Torvalds #define ORIGIN_HASH_SIZE 256 1141da177e4SLinus Torvalds #define ORIGIN_MASK 0xFF 1151da177e4SLinus Torvalds static struct list_head *_origins; 1161da177e4SLinus Torvalds static struct rw_semaphore _origins_lock; 1171da177e4SLinus Torvalds 1181da177e4SLinus Torvalds static int init_origin_hash(void) 1191da177e4SLinus Torvalds { 1201da177e4SLinus Torvalds int i; 1211da177e4SLinus Torvalds 1221da177e4SLinus Torvalds _origins = kmalloc(ORIGIN_HASH_SIZE * sizeof(struct list_head), 1231da177e4SLinus Torvalds GFP_KERNEL); 1241da177e4SLinus Torvalds if (!_origins) { 12572d94861SAlasdair G Kergon DMERR("unable to allocate memory"); 1261da177e4SLinus Torvalds return -ENOMEM; 1271da177e4SLinus Torvalds } 1281da177e4SLinus Torvalds 1291da177e4SLinus Torvalds for (i = 0; i < ORIGIN_HASH_SIZE; i++) 1301da177e4SLinus Torvalds INIT_LIST_HEAD(_origins + i); 1311da177e4SLinus Torvalds init_rwsem(&_origins_lock); 1321da177e4SLinus Torvalds 1331da177e4SLinus Torvalds return 0; 1341da177e4SLinus Torvalds } 1351da177e4SLinus Torvalds 1361da177e4SLinus Torvalds static void exit_origin_hash(void) 1371da177e4SLinus Torvalds { 1381da177e4SLinus Torvalds kfree(_origins); 1391da177e4SLinus Torvalds } 1401da177e4SLinus Torvalds 141028867acSAlasdair G Kergon static unsigned origin_hash(struct block_device *bdev) 1421da177e4SLinus Torvalds { 1431da177e4SLinus Torvalds return bdev->bd_dev & ORIGIN_MASK; 1441da177e4SLinus Torvalds } 1451da177e4SLinus Torvalds 1461da177e4SLinus Torvalds static struct origin *__lookup_origin(struct block_device *origin) 1471da177e4SLinus Torvalds { 1481da177e4SLinus Torvalds struct list_head *ol; 1491da177e4SLinus Torvalds struct origin *o; 1501da177e4SLinus Torvalds 1511da177e4SLinus Torvalds ol = &_origins[origin_hash(origin)]; 1521da177e4SLinus Torvalds list_for_each_entry (o, ol, hash_list) 1531da177e4SLinus Torvalds if (bdev_equal(o->bdev, origin)) 1541da177e4SLinus Torvalds return o; 1551da177e4SLinus Torvalds 1561da177e4SLinus Torvalds return NULL; 1571da177e4SLinus Torvalds } 1581da177e4SLinus Torvalds 1591da177e4SLinus Torvalds static void __insert_origin(struct origin *o) 1601da177e4SLinus Torvalds { 1611da177e4SLinus Torvalds struct list_head *sl = &_origins[origin_hash(o->bdev)]; 1621da177e4SLinus Torvalds list_add_tail(&o->hash_list, sl); 1631da177e4SLinus Torvalds } 1641da177e4SLinus Torvalds 1651da177e4SLinus Torvalds /* 1661da177e4SLinus Torvalds * Make a note of the snapshot and its origin so we can look it 1671da177e4SLinus Torvalds * up when the origin has a write on it. 1681da177e4SLinus Torvalds */ 1691da177e4SLinus Torvalds static int register_snapshot(struct dm_snapshot *snap) 1701da177e4SLinus Torvalds { 1711da177e4SLinus Torvalds struct origin *o; 1721da177e4SLinus Torvalds struct block_device *bdev = snap->origin->bdev; 1731da177e4SLinus Torvalds 1741da177e4SLinus Torvalds down_write(&_origins_lock); 1751da177e4SLinus Torvalds o = __lookup_origin(bdev); 1761da177e4SLinus Torvalds 1771da177e4SLinus Torvalds if (!o) { 1781da177e4SLinus Torvalds /* New origin */ 1791da177e4SLinus Torvalds o = kmalloc(sizeof(*o), GFP_KERNEL); 1801da177e4SLinus Torvalds if (!o) { 1811da177e4SLinus Torvalds up_write(&_origins_lock); 1821da177e4SLinus Torvalds return -ENOMEM; 1831da177e4SLinus Torvalds } 1841da177e4SLinus Torvalds 1851da177e4SLinus Torvalds /* Initialise the struct */ 1861da177e4SLinus Torvalds INIT_LIST_HEAD(&o->snapshots); 1871da177e4SLinus Torvalds o->bdev = bdev; 1881da177e4SLinus Torvalds 1891da177e4SLinus Torvalds __insert_origin(o); 1901da177e4SLinus Torvalds } 1911da177e4SLinus Torvalds 1921da177e4SLinus Torvalds list_add_tail(&snap->list, &o->snapshots); 1931da177e4SLinus Torvalds 1941da177e4SLinus Torvalds up_write(&_origins_lock); 1951da177e4SLinus Torvalds return 0; 1961da177e4SLinus Torvalds } 1971da177e4SLinus Torvalds 1981da177e4SLinus Torvalds static void unregister_snapshot(struct dm_snapshot *s) 1991da177e4SLinus Torvalds { 2001da177e4SLinus Torvalds struct origin *o; 2011da177e4SLinus Torvalds 2021da177e4SLinus Torvalds down_write(&_origins_lock); 2031da177e4SLinus Torvalds o = __lookup_origin(s->origin->bdev); 2041da177e4SLinus Torvalds 2051da177e4SLinus Torvalds list_del(&s->list); 2061da177e4SLinus Torvalds if (list_empty(&o->snapshots)) { 2071da177e4SLinus Torvalds list_del(&o->hash_list); 2081da177e4SLinus Torvalds kfree(o); 2091da177e4SLinus Torvalds } 2101da177e4SLinus Torvalds 2111da177e4SLinus Torvalds up_write(&_origins_lock); 2121da177e4SLinus Torvalds } 2131da177e4SLinus Torvalds 2141da177e4SLinus Torvalds /* 2151da177e4SLinus Torvalds * Implementation of the exception hash tables. 2161da177e4SLinus Torvalds */ 2171da177e4SLinus Torvalds static int init_exception_table(struct exception_table *et, uint32_t size) 2181da177e4SLinus Torvalds { 2191da177e4SLinus Torvalds unsigned int i; 2201da177e4SLinus Torvalds 2211da177e4SLinus Torvalds et->hash_mask = size - 1; 2221da177e4SLinus Torvalds et->table = dm_vcalloc(size, sizeof(struct list_head)); 2231da177e4SLinus Torvalds if (!et->table) 2241da177e4SLinus Torvalds return -ENOMEM; 2251da177e4SLinus Torvalds 2261da177e4SLinus Torvalds for (i = 0; i < size; i++) 2271da177e4SLinus Torvalds INIT_LIST_HEAD(et->table + i); 2281da177e4SLinus Torvalds 2291da177e4SLinus Torvalds return 0; 2301da177e4SLinus Torvalds } 2311da177e4SLinus Torvalds 232e18b890bSChristoph Lameter static void exit_exception_table(struct exception_table *et, struct kmem_cache *mem) 2331da177e4SLinus Torvalds { 2341da177e4SLinus Torvalds struct list_head *slot; 235028867acSAlasdair G Kergon struct dm_snap_exception *ex, *next; 2361da177e4SLinus Torvalds int i, size; 2371da177e4SLinus Torvalds 2381da177e4SLinus Torvalds size = et->hash_mask + 1; 2391da177e4SLinus Torvalds for (i = 0; i < size; i++) { 2401da177e4SLinus Torvalds slot = et->table + i; 2411da177e4SLinus Torvalds 2421da177e4SLinus Torvalds list_for_each_entry_safe (ex, next, slot, hash_list) 2431da177e4SLinus Torvalds kmem_cache_free(mem, ex); 2441da177e4SLinus Torvalds } 2451da177e4SLinus Torvalds 2461da177e4SLinus Torvalds vfree(et->table); 2471da177e4SLinus Torvalds } 2481da177e4SLinus Torvalds 249028867acSAlasdair G Kergon static uint32_t exception_hash(struct exception_table *et, chunk_t chunk) 2501da177e4SLinus Torvalds { 2511da177e4SLinus Torvalds return chunk & et->hash_mask; 2521da177e4SLinus Torvalds } 2531da177e4SLinus Torvalds 254028867acSAlasdair G Kergon static void insert_exception(struct exception_table *eh, 255028867acSAlasdair G Kergon struct dm_snap_exception *e) 2561da177e4SLinus Torvalds { 2571da177e4SLinus Torvalds struct list_head *l = &eh->table[exception_hash(eh, e->old_chunk)]; 2581da177e4SLinus Torvalds list_add(&e->hash_list, l); 2591da177e4SLinus Torvalds } 2601da177e4SLinus Torvalds 261028867acSAlasdair G Kergon static void remove_exception(struct dm_snap_exception *e) 2621da177e4SLinus Torvalds { 2631da177e4SLinus Torvalds list_del(&e->hash_list); 2641da177e4SLinus Torvalds } 2651da177e4SLinus Torvalds 2661da177e4SLinus Torvalds /* 2671da177e4SLinus Torvalds * Return the exception data for a sector, or NULL if not 2681da177e4SLinus Torvalds * remapped. 2691da177e4SLinus Torvalds */ 270028867acSAlasdair G Kergon static struct dm_snap_exception *lookup_exception(struct exception_table *et, 2711da177e4SLinus Torvalds chunk_t chunk) 2721da177e4SLinus Torvalds { 2731da177e4SLinus Torvalds struct list_head *slot; 274028867acSAlasdair G Kergon struct dm_snap_exception *e; 2751da177e4SLinus Torvalds 2761da177e4SLinus Torvalds slot = &et->table[exception_hash(et, chunk)]; 2771da177e4SLinus Torvalds list_for_each_entry (e, slot, hash_list) 2781da177e4SLinus Torvalds if (e->old_chunk == chunk) 2791da177e4SLinus Torvalds return e; 2801da177e4SLinus Torvalds 2811da177e4SLinus Torvalds return NULL; 2821da177e4SLinus Torvalds } 2831da177e4SLinus Torvalds 284028867acSAlasdair G Kergon static struct dm_snap_exception *alloc_exception(void) 2851da177e4SLinus Torvalds { 286028867acSAlasdair G Kergon struct dm_snap_exception *e; 2871da177e4SLinus Torvalds 2881da177e4SLinus Torvalds e = kmem_cache_alloc(exception_cache, GFP_NOIO); 2891da177e4SLinus Torvalds if (!e) 2901da177e4SLinus Torvalds e = kmem_cache_alloc(exception_cache, GFP_ATOMIC); 2911da177e4SLinus Torvalds 2921da177e4SLinus Torvalds return e; 2931da177e4SLinus Torvalds } 2941da177e4SLinus Torvalds 295028867acSAlasdair G Kergon static void free_exception(struct dm_snap_exception *e) 2961da177e4SLinus Torvalds { 2971da177e4SLinus Torvalds kmem_cache_free(exception_cache, e); 2981da177e4SLinus Torvalds } 2991da177e4SLinus Torvalds 300028867acSAlasdair G Kergon static struct dm_snap_pending_exception *alloc_pending_exception(void) 3011da177e4SLinus Torvalds { 3021da177e4SLinus Torvalds return mempool_alloc(pending_pool, GFP_NOIO); 3031da177e4SLinus Torvalds } 3041da177e4SLinus Torvalds 305028867acSAlasdair G Kergon static void free_pending_exception(struct dm_snap_pending_exception *pe) 3061da177e4SLinus Torvalds { 3071da177e4SLinus Torvalds mempool_free(pe, pending_pool); 3081da177e4SLinus Torvalds } 3091da177e4SLinus Torvalds 3101da177e4SLinus Torvalds int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new) 3111da177e4SLinus Torvalds { 312028867acSAlasdair G Kergon struct dm_snap_exception *e; 3131da177e4SLinus Torvalds 3141da177e4SLinus Torvalds e = alloc_exception(); 3151da177e4SLinus Torvalds if (!e) 3161da177e4SLinus Torvalds return -ENOMEM; 3171da177e4SLinus Torvalds 3181da177e4SLinus Torvalds e->old_chunk = old; 3191da177e4SLinus Torvalds e->new_chunk = new; 3201da177e4SLinus Torvalds insert_exception(&s->complete, e); 3211da177e4SLinus Torvalds return 0; 3221da177e4SLinus Torvalds } 3231da177e4SLinus Torvalds 3241da177e4SLinus Torvalds /* 3251da177e4SLinus Torvalds * Hard coded magic. 3261da177e4SLinus Torvalds */ 3271da177e4SLinus Torvalds static int calc_max_buckets(void) 3281da177e4SLinus Torvalds { 3291da177e4SLinus Torvalds /* use a fixed size of 2MB */ 3301da177e4SLinus Torvalds unsigned long mem = 2 * 1024 * 1024; 3311da177e4SLinus Torvalds mem /= sizeof(struct list_head); 3321da177e4SLinus Torvalds 3331da177e4SLinus Torvalds return mem; 3341da177e4SLinus Torvalds } 3351da177e4SLinus Torvalds 3361da177e4SLinus Torvalds /* 3371da177e4SLinus Torvalds * Rounds a number down to a power of 2. 3381da177e4SLinus Torvalds */ 339028867acSAlasdair G Kergon static uint32_t round_down(uint32_t n) 3401da177e4SLinus Torvalds { 3411da177e4SLinus Torvalds while (n & (n - 1)) 3421da177e4SLinus Torvalds n &= (n - 1); 3431da177e4SLinus Torvalds return n; 3441da177e4SLinus Torvalds } 3451da177e4SLinus Torvalds 3461da177e4SLinus Torvalds /* 3471da177e4SLinus Torvalds * Allocate room for a suitable hash table. 3481da177e4SLinus Torvalds */ 3491da177e4SLinus Torvalds static int init_hash_tables(struct dm_snapshot *s) 3501da177e4SLinus Torvalds { 3511da177e4SLinus Torvalds sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets; 3521da177e4SLinus Torvalds 3531da177e4SLinus Torvalds /* 3541da177e4SLinus Torvalds * Calculate based on the size of the original volume or 3551da177e4SLinus Torvalds * the COW volume... 3561da177e4SLinus Torvalds */ 3571da177e4SLinus Torvalds cow_dev_size = get_dev_size(s->cow->bdev); 3581da177e4SLinus Torvalds origin_dev_size = get_dev_size(s->origin->bdev); 3591da177e4SLinus Torvalds max_buckets = calc_max_buckets(); 3601da177e4SLinus Torvalds 3611da177e4SLinus Torvalds hash_size = min(origin_dev_size, cow_dev_size) >> s->chunk_shift; 3621da177e4SLinus Torvalds hash_size = min(hash_size, max_buckets); 3631da177e4SLinus Torvalds 3641da177e4SLinus Torvalds /* Round it down to a power of 2 */ 3651da177e4SLinus Torvalds hash_size = round_down(hash_size); 3661da177e4SLinus Torvalds if (init_exception_table(&s->complete, hash_size)) 3671da177e4SLinus Torvalds return -ENOMEM; 3681da177e4SLinus Torvalds 3691da177e4SLinus Torvalds /* 3701da177e4SLinus Torvalds * Allocate hash table for in-flight exceptions 3711da177e4SLinus Torvalds * Make this smaller than the real hash table 3721da177e4SLinus Torvalds */ 3731da177e4SLinus Torvalds hash_size >>= 3; 3741da177e4SLinus Torvalds if (hash_size < 64) 3751da177e4SLinus Torvalds hash_size = 64; 3761da177e4SLinus Torvalds 3771da177e4SLinus Torvalds if (init_exception_table(&s->pending, hash_size)) { 3781da177e4SLinus Torvalds exit_exception_table(&s->complete, exception_cache); 3791da177e4SLinus Torvalds return -ENOMEM; 3801da177e4SLinus Torvalds } 3811da177e4SLinus Torvalds 3821da177e4SLinus Torvalds return 0; 3831da177e4SLinus Torvalds } 3841da177e4SLinus Torvalds 3851da177e4SLinus Torvalds /* 3861da177e4SLinus Torvalds * Round a number up to the nearest 'size' boundary. size must 3871da177e4SLinus Torvalds * be a power of 2. 3881da177e4SLinus Torvalds */ 389028867acSAlasdair G Kergon static ulong round_up(ulong n, ulong size) 3901da177e4SLinus Torvalds { 3911da177e4SLinus Torvalds size--; 3921da177e4SLinus Torvalds return (n + size) & ~size; 3931da177e4SLinus Torvalds } 3941da177e4SLinus Torvalds 3954c7e3bf4SMark McLoughlin static int set_chunk_size(struct dm_snapshot *s, const char *chunk_size_arg, 3964c7e3bf4SMark McLoughlin char **error) 3974c7e3bf4SMark McLoughlin { 3984c7e3bf4SMark McLoughlin unsigned long chunk_size; 3994c7e3bf4SMark McLoughlin char *value; 4004c7e3bf4SMark McLoughlin 4014c7e3bf4SMark McLoughlin chunk_size = simple_strtoul(chunk_size_arg, &value, 10); 4024c7e3bf4SMark McLoughlin if (*chunk_size_arg == '\0' || *value != '\0') { 4034c7e3bf4SMark McLoughlin *error = "Invalid chunk size"; 4044c7e3bf4SMark McLoughlin return -EINVAL; 4054c7e3bf4SMark McLoughlin } 4064c7e3bf4SMark McLoughlin 4074c7e3bf4SMark McLoughlin if (!chunk_size) { 4084c7e3bf4SMark McLoughlin s->chunk_size = s->chunk_mask = s->chunk_shift = 0; 4094c7e3bf4SMark McLoughlin return 0; 4104c7e3bf4SMark McLoughlin } 4114c7e3bf4SMark McLoughlin 4124c7e3bf4SMark McLoughlin /* 4134c7e3bf4SMark McLoughlin * Chunk size must be multiple of page size. Silently 4144c7e3bf4SMark McLoughlin * round up if it's not. 4154c7e3bf4SMark McLoughlin */ 4164c7e3bf4SMark McLoughlin chunk_size = round_up(chunk_size, PAGE_SIZE >> 9); 4174c7e3bf4SMark McLoughlin 4184c7e3bf4SMark McLoughlin /* Check chunk_size is a power of 2 */ 4196f3c3f0aSvignesh babu if (!is_power_of_2(chunk_size)) { 4204c7e3bf4SMark McLoughlin *error = "Chunk size is not a power of 2"; 4214c7e3bf4SMark McLoughlin return -EINVAL; 4224c7e3bf4SMark McLoughlin } 4234c7e3bf4SMark McLoughlin 4244c7e3bf4SMark McLoughlin /* Validate the chunk size against the device block size */ 4254c7e3bf4SMark McLoughlin if (chunk_size % (bdev_hardsect_size(s->cow->bdev) >> 9)) { 4264c7e3bf4SMark McLoughlin *error = "Chunk size is not a multiple of device blocksize"; 4274c7e3bf4SMark McLoughlin return -EINVAL; 4284c7e3bf4SMark McLoughlin } 4294c7e3bf4SMark McLoughlin 4304c7e3bf4SMark McLoughlin s->chunk_size = chunk_size; 4314c7e3bf4SMark McLoughlin s->chunk_mask = chunk_size - 1; 4324c7e3bf4SMark McLoughlin s->chunk_shift = ffs(chunk_size) - 1; 4334c7e3bf4SMark McLoughlin 4344c7e3bf4SMark McLoughlin return 0; 4354c7e3bf4SMark McLoughlin } 4364c7e3bf4SMark McLoughlin 4371da177e4SLinus Torvalds /* 4381da177e4SLinus Torvalds * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size> 4391da177e4SLinus Torvalds */ 4401da177e4SLinus Torvalds static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) 4411da177e4SLinus Torvalds { 4421da177e4SLinus Torvalds struct dm_snapshot *s; 4431da177e4SLinus Torvalds int r = -EINVAL; 4441da177e4SLinus Torvalds char persistent; 4451da177e4SLinus Torvalds char *origin_path; 4461da177e4SLinus Torvalds char *cow_path; 4471da177e4SLinus Torvalds 4484c7e3bf4SMark McLoughlin if (argc != 4) { 44972d94861SAlasdair G Kergon ti->error = "requires exactly 4 arguments"; 4501da177e4SLinus Torvalds r = -EINVAL; 4511da177e4SLinus Torvalds goto bad1; 4521da177e4SLinus Torvalds } 4531da177e4SLinus Torvalds 4541da177e4SLinus Torvalds origin_path = argv[0]; 4551da177e4SLinus Torvalds cow_path = argv[1]; 4561da177e4SLinus Torvalds persistent = toupper(*argv[2]); 4571da177e4SLinus Torvalds 4581da177e4SLinus Torvalds if (persistent != 'P' && persistent != 'N') { 4591da177e4SLinus Torvalds ti->error = "Persistent flag is not P or N"; 4601da177e4SLinus Torvalds r = -EINVAL; 4611da177e4SLinus Torvalds goto bad1; 4621da177e4SLinus Torvalds } 4631da177e4SLinus Torvalds 4641da177e4SLinus Torvalds s = kmalloc(sizeof(*s), GFP_KERNEL); 4651da177e4SLinus Torvalds if (s == NULL) { 4661da177e4SLinus Torvalds ti->error = "Cannot allocate snapshot context private " 4671da177e4SLinus Torvalds "structure"; 4681da177e4SLinus Torvalds r = -ENOMEM; 4691da177e4SLinus Torvalds goto bad1; 4701da177e4SLinus Torvalds } 4711da177e4SLinus Torvalds 4721da177e4SLinus Torvalds r = dm_get_device(ti, origin_path, 0, ti->len, FMODE_READ, &s->origin); 4731da177e4SLinus Torvalds if (r) { 4741da177e4SLinus Torvalds ti->error = "Cannot get origin device"; 4751da177e4SLinus Torvalds goto bad2; 4761da177e4SLinus Torvalds } 4771da177e4SLinus Torvalds 4781da177e4SLinus Torvalds r = dm_get_device(ti, cow_path, 0, 0, 4791da177e4SLinus Torvalds FMODE_READ | FMODE_WRITE, &s->cow); 4801da177e4SLinus Torvalds if (r) { 4811da177e4SLinus Torvalds dm_put_device(ti, s->origin); 4821da177e4SLinus Torvalds ti->error = "Cannot get COW device"; 4831da177e4SLinus Torvalds goto bad2; 4841da177e4SLinus Torvalds } 4851da177e4SLinus Torvalds 4864c7e3bf4SMark McLoughlin r = set_chunk_size(s, argv[3], &ti->error); 4874c7e3bf4SMark McLoughlin if (r) 4881da177e4SLinus Torvalds goto bad3; 4891da177e4SLinus Torvalds 4901da177e4SLinus Torvalds s->type = persistent; 4911da177e4SLinus Torvalds 4921da177e4SLinus Torvalds s->valid = 1; 493aa14edebSAlasdair G Kergon s->active = 0; 4941da177e4SLinus Torvalds s->last_percent = 0; 4951da177e4SLinus Torvalds init_rwsem(&s->lock); 496ca3a931fSAlasdair G Kergon spin_lock_init(&s->pe_lock); 4971da177e4SLinus Torvalds s->table = ti->table; 4981da177e4SLinus Torvalds 4991da177e4SLinus Torvalds /* Allocate hash table for COW data */ 5001da177e4SLinus Torvalds if (init_hash_tables(s)) { 5011da177e4SLinus Torvalds ti->error = "Unable to allocate hash table space"; 5021da177e4SLinus Torvalds r = -ENOMEM; 5031da177e4SLinus Torvalds goto bad3; 5041da177e4SLinus Torvalds } 5051da177e4SLinus Torvalds 5061da177e4SLinus Torvalds s->store.snap = s; 5071da177e4SLinus Torvalds 5081da177e4SLinus Torvalds if (persistent == 'P') 5094c7e3bf4SMark McLoughlin r = dm_create_persistent(&s->store); 5101da177e4SLinus Torvalds else 5114c7e3bf4SMark McLoughlin r = dm_create_transient(&s->store); 5121da177e4SLinus Torvalds 5131da177e4SLinus Torvalds if (r) { 5141da177e4SLinus Torvalds ti->error = "Couldn't create exception store"; 5151da177e4SLinus Torvalds r = -EINVAL; 5161da177e4SLinus Torvalds goto bad4; 5171da177e4SLinus Torvalds } 5181da177e4SLinus Torvalds 5191da177e4SLinus Torvalds r = kcopyd_client_create(SNAPSHOT_PAGES, &s->kcopyd_client); 5201da177e4SLinus Torvalds if (r) { 5211da177e4SLinus Torvalds ti->error = "Could not create kcopyd client"; 5221da177e4SLinus Torvalds goto bad5; 5231da177e4SLinus Torvalds } 5241da177e4SLinus Torvalds 525aa14edebSAlasdair G Kergon /* Metadata must only be loaded into one table at once */ 526f9cea4f7SMark McLoughlin r = s->store.read_metadata(&s->store); 5270764147bSMilan Broz if (r < 0) { 528f9cea4f7SMark McLoughlin ti->error = "Failed to read snapshot metadata"; 529f9cea4f7SMark McLoughlin goto bad6; 5300764147bSMilan Broz } else if (r > 0) { 5310764147bSMilan Broz s->valid = 0; 5320764147bSMilan Broz DMWARN("Snapshot is marked invalid."); 533f9cea4f7SMark McLoughlin } 534aa14edebSAlasdair G Kergon 535ca3a931fSAlasdair G Kergon bio_list_init(&s->queued_bios); 536c4028958SDavid Howells INIT_WORK(&s->queued_bios_work, flush_queued_bios); 537ca3a931fSAlasdair G Kergon 5381da177e4SLinus Torvalds /* Add snapshot to the list of snapshots for this origin */ 539aa14edebSAlasdair G Kergon /* Exceptions aren't triggered till snapshot_resume() is called */ 5401da177e4SLinus Torvalds if (register_snapshot(s)) { 5411da177e4SLinus Torvalds r = -EINVAL; 5421da177e4SLinus Torvalds ti->error = "Cannot register snapshot origin"; 5431da177e4SLinus Torvalds goto bad6; 5441da177e4SLinus Torvalds } 5451da177e4SLinus Torvalds 5461da177e4SLinus Torvalds ti->private = s; 547c51c2752SAlasdair G Kergon ti->split_io = s->chunk_size; 5481da177e4SLinus Torvalds 5491da177e4SLinus Torvalds return 0; 5501da177e4SLinus Torvalds 5511da177e4SLinus Torvalds bad6: 5521da177e4SLinus Torvalds kcopyd_client_destroy(s->kcopyd_client); 5531da177e4SLinus Torvalds 5541da177e4SLinus Torvalds bad5: 5551da177e4SLinus Torvalds s->store.destroy(&s->store); 5561da177e4SLinus Torvalds 5571da177e4SLinus Torvalds bad4: 5581da177e4SLinus Torvalds exit_exception_table(&s->pending, pending_cache); 5591da177e4SLinus Torvalds exit_exception_table(&s->complete, exception_cache); 5601da177e4SLinus Torvalds 5611da177e4SLinus Torvalds bad3: 5621da177e4SLinus Torvalds dm_put_device(ti, s->cow); 5631da177e4SLinus Torvalds dm_put_device(ti, s->origin); 5641da177e4SLinus Torvalds 5651da177e4SLinus Torvalds bad2: 5661da177e4SLinus Torvalds kfree(s); 5671da177e4SLinus Torvalds 5681da177e4SLinus Torvalds bad1: 5691da177e4SLinus Torvalds return r; 5701da177e4SLinus Torvalds } 5711da177e4SLinus Torvalds 57231c93a0cSMilan Broz static void __free_exceptions(struct dm_snapshot *s) 57331c93a0cSMilan Broz { 57431c93a0cSMilan Broz kcopyd_client_destroy(s->kcopyd_client); 57531c93a0cSMilan Broz s->kcopyd_client = NULL; 57631c93a0cSMilan Broz 57731c93a0cSMilan Broz exit_exception_table(&s->pending, pending_cache); 57831c93a0cSMilan Broz exit_exception_table(&s->complete, exception_cache); 57931c93a0cSMilan Broz 58031c93a0cSMilan Broz s->store.destroy(&s->store); 58131c93a0cSMilan Broz } 58231c93a0cSMilan Broz 5831da177e4SLinus Torvalds static void snapshot_dtr(struct dm_target *ti) 5841da177e4SLinus Torvalds { 585028867acSAlasdair G Kergon struct dm_snapshot *s = ti->private; 5861da177e4SLinus Torvalds 587ca3a931fSAlasdair G Kergon flush_workqueue(ksnapd); 588ca3a931fSAlasdair G Kergon 589138728dcSAlasdair G Kergon /* Prevent further origin writes from using this snapshot. */ 590138728dcSAlasdair G Kergon /* After this returns there can be no new kcopyd jobs. */ 5911da177e4SLinus Torvalds unregister_snapshot(s); 5921da177e4SLinus Torvalds 59331c93a0cSMilan Broz __free_exceptions(s); 5941da177e4SLinus Torvalds 5951da177e4SLinus Torvalds dm_put_device(ti, s->origin); 5961da177e4SLinus Torvalds dm_put_device(ti, s->cow); 597138728dcSAlasdair G Kergon 5981da177e4SLinus Torvalds kfree(s); 5991da177e4SLinus Torvalds } 6001da177e4SLinus Torvalds 6011da177e4SLinus Torvalds /* 6021da177e4SLinus Torvalds * Flush a list of buffers. 6031da177e4SLinus Torvalds */ 6041da177e4SLinus Torvalds static void flush_bios(struct bio *bio) 6051da177e4SLinus Torvalds { 6061da177e4SLinus Torvalds struct bio *n; 6071da177e4SLinus Torvalds 6081da177e4SLinus Torvalds while (bio) { 6091da177e4SLinus Torvalds n = bio->bi_next; 6101da177e4SLinus Torvalds bio->bi_next = NULL; 6111da177e4SLinus Torvalds generic_make_request(bio); 6121da177e4SLinus Torvalds bio = n; 6131da177e4SLinus Torvalds } 6141da177e4SLinus Torvalds } 6151da177e4SLinus Torvalds 616c4028958SDavid Howells static void flush_queued_bios(struct work_struct *work) 617ca3a931fSAlasdair G Kergon { 618c4028958SDavid Howells struct dm_snapshot *s = 619c4028958SDavid Howells container_of(work, struct dm_snapshot, queued_bios_work); 620ca3a931fSAlasdair G Kergon struct bio *queued_bios; 621ca3a931fSAlasdair G Kergon unsigned long flags; 622ca3a931fSAlasdair G Kergon 623ca3a931fSAlasdair G Kergon spin_lock_irqsave(&s->pe_lock, flags); 624ca3a931fSAlasdair G Kergon queued_bios = bio_list_get(&s->queued_bios); 625ca3a931fSAlasdair G Kergon spin_unlock_irqrestore(&s->pe_lock, flags); 626ca3a931fSAlasdair G Kergon 627ca3a931fSAlasdair G Kergon flush_bios(queued_bios); 628ca3a931fSAlasdair G Kergon } 629ca3a931fSAlasdair G Kergon 6301da177e4SLinus Torvalds /* 6311da177e4SLinus Torvalds * Error a list of buffers. 6321da177e4SLinus Torvalds */ 6331da177e4SLinus Torvalds static void error_bios(struct bio *bio) 6341da177e4SLinus Torvalds { 6351da177e4SLinus Torvalds struct bio *n; 6361da177e4SLinus Torvalds 6371da177e4SLinus Torvalds while (bio) { 6381da177e4SLinus Torvalds n = bio->bi_next; 6391da177e4SLinus Torvalds bio->bi_next = NULL; 6406712ecf8SNeilBrown bio_io_error(bio); 6411da177e4SLinus Torvalds bio = n; 6421da177e4SLinus Torvalds } 6431da177e4SLinus Torvalds } 6441da177e4SLinus Torvalds 645695368acSAlasdair G Kergon static void __invalidate_snapshot(struct dm_snapshot *s, int err) 64676df1c65SAlasdair G Kergon { 64776df1c65SAlasdair G Kergon if (!s->valid) 64876df1c65SAlasdair G Kergon return; 64976df1c65SAlasdair G Kergon 65076df1c65SAlasdair G Kergon if (err == -EIO) 65176df1c65SAlasdair G Kergon DMERR("Invalidating snapshot: Error reading/writing."); 65276df1c65SAlasdair G Kergon else if (err == -ENOMEM) 65376df1c65SAlasdair G Kergon DMERR("Invalidating snapshot: Unable to allocate exception."); 65476df1c65SAlasdair G Kergon 65576df1c65SAlasdair G Kergon if (s->store.drop_snapshot) 65676df1c65SAlasdair G Kergon s->store.drop_snapshot(&s->store); 65776df1c65SAlasdair G Kergon 65876df1c65SAlasdair G Kergon s->valid = 0; 65976df1c65SAlasdair G Kergon 66076df1c65SAlasdair G Kergon dm_table_event(s->table); 66176df1c65SAlasdair G Kergon } 66276df1c65SAlasdair G Kergon 663028867acSAlasdair G Kergon static void get_pending_exception(struct dm_snap_pending_exception *pe) 6644b832e8dSAlasdair G Kergon { 6654b832e8dSAlasdair G Kergon atomic_inc(&pe->ref_count); 6664b832e8dSAlasdair G Kergon } 6674b832e8dSAlasdair G Kergon 668028867acSAlasdair G Kergon static struct bio *put_pending_exception(struct dm_snap_pending_exception *pe) 6694b832e8dSAlasdair G Kergon { 670028867acSAlasdair G Kergon struct dm_snap_pending_exception *primary_pe; 6714b832e8dSAlasdair G Kergon struct bio *origin_bios = NULL; 6724b832e8dSAlasdair G Kergon 6734b832e8dSAlasdair G Kergon primary_pe = pe->primary_pe; 6744b832e8dSAlasdair G Kergon 6754b832e8dSAlasdair G Kergon /* 6764b832e8dSAlasdair G Kergon * If this pe is involved in a write to the origin and 6774b832e8dSAlasdair G Kergon * it is the last sibling to complete then release 6784b832e8dSAlasdair G Kergon * the bios for the original write to the origin. 6794b832e8dSAlasdair G Kergon */ 6804b832e8dSAlasdair G Kergon if (primary_pe && 6814b832e8dSAlasdair G Kergon atomic_dec_and_test(&primary_pe->ref_count)) 6824b832e8dSAlasdair G Kergon origin_bios = bio_list_get(&primary_pe->origin_bios); 6834b832e8dSAlasdair G Kergon 6844b832e8dSAlasdair G Kergon /* 6854b832e8dSAlasdair G Kergon * Free the pe if it's not linked to an origin write or if 6864b832e8dSAlasdair G Kergon * it's not itself a primary pe. 6874b832e8dSAlasdair G Kergon */ 6884b832e8dSAlasdair G Kergon if (!primary_pe || primary_pe != pe) 6894b832e8dSAlasdair G Kergon free_pending_exception(pe); 6904b832e8dSAlasdair G Kergon 6914b832e8dSAlasdair G Kergon /* 6924b832e8dSAlasdair G Kergon * Free the primary pe if nothing references it. 6934b832e8dSAlasdair G Kergon */ 6944b832e8dSAlasdair G Kergon if (primary_pe && !atomic_read(&primary_pe->ref_count)) 6954b832e8dSAlasdair G Kergon free_pending_exception(primary_pe); 6964b832e8dSAlasdair G Kergon 6974b832e8dSAlasdair G Kergon return origin_bios; 6984b832e8dSAlasdair G Kergon } 6994b832e8dSAlasdair G Kergon 700028867acSAlasdair G Kergon static void pending_complete(struct dm_snap_pending_exception *pe, int success) 7011da177e4SLinus Torvalds { 702028867acSAlasdair G Kergon struct dm_snap_exception *e; 7031da177e4SLinus Torvalds struct dm_snapshot *s = pe->snap; 7049d493fa8SAlasdair G Kergon struct bio *origin_bios = NULL; 7059d493fa8SAlasdair G Kergon struct bio *snapshot_bios = NULL; 7069d493fa8SAlasdair G Kergon int error = 0; 7071da177e4SLinus Torvalds 70876df1c65SAlasdair G Kergon if (!success) { 70976df1c65SAlasdair G Kergon /* Read/write error - snapshot is unusable */ 7101da177e4SLinus Torvalds down_write(&s->lock); 711695368acSAlasdair G Kergon __invalidate_snapshot(s, -EIO); 7129d493fa8SAlasdair G Kergon error = 1; 71376df1c65SAlasdair G Kergon goto out; 71476df1c65SAlasdair G Kergon } 71576df1c65SAlasdair G Kergon 71676df1c65SAlasdair G Kergon e = alloc_exception(); 71776df1c65SAlasdair G Kergon if (!e) { 71876df1c65SAlasdair G Kergon down_write(&s->lock); 719695368acSAlasdair G Kergon __invalidate_snapshot(s, -ENOMEM); 7209d493fa8SAlasdair G Kergon error = 1; 7211da177e4SLinus Torvalds goto out; 7221da177e4SLinus Torvalds } 7231da177e4SLinus Torvalds *e = pe->e; 7241da177e4SLinus Torvalds 7259d493fa8SAlasdair G Kergon down_write(&s->lock); 7269d493fa8SAlasdair G Kergon if (!s->valid) { 7279d493fa8SAlasdair G Kergon free_exception(e); 7289d493fa8SAlasdair G Kergon error = 1; 7299d493fa8SAlasdair G Kergon goto out; 7309d493fa8SAlasdair G Kergon } 7319d493fa8SAlasdair G Kergon 7321da177e4SLinus Torvalds /* 7331da177e4SLinus Torvalds * Add a proper exception, and remove the 7341da177e4SLinus Torvalds * in-flight exception from the list. 7351da177e4SLinus Torvalds */ 7361da177e4SLinus Torvalds insert_exception(&s->complete, e); 7371da177e4SLinus Torvalds 7381da177e4SLinus Torvalds out: 739695368acSAlasdair G Kergon remove_exception(&pe->e); 7409d493fa8SAlasdair G Kergon snapshot_bios = bio_list_get(&pe->snapshot_bios); 7414b832e8dSAlasdair G Kergon origin_bios = put_pending_exception(pe); 742b4b610f6SAlasdair G Kergon 7439d493fa8SAlasdair G Kergon up_write(&s->lock); 7449d493fa8SAlasdair G Kergon 7459d493fa8SAlasdair G Kergon /* Submit any pending write bios */ 7469d493fa8SAlasdair G Kergon if (error) 7479d493fa8SAlasdair G Kergon error_bios(snapshot_bios); 7489d493fa8SAlasdair G Kergon else 7499d493fa8SAlasdair G Kergon flush_bios(snapshot_bios); 7509d493fa8SAlasdair G Kergon 7519d493fa8SAlasdair G Kergon flush_bios(origin_bios); 7521da177e4SLinus Torvalds } 7531da177e4SLinus Torvalds 7541da177e4SLinus Torvalds static void commit_callback(void *context, int success) 7551da177e4SLinus Torvalds { 756028867acSAlasdair G Kergon struct dm_snap_pending_exception *pe = context; 757028867acSAlasdair G Kergon 7581da177e4SLinus Torvalds pending_complete(pe, success); 7591da177e4SLinus Torvalds } 7601da177e4SLinus Torvalds 7611da177e4SLinus Torvalds /* 7621da177e4SLinus Torvalds * Called when the copy I/O has finished. kcopyd actually runs 7631da177e4SLinus Torvalds * this code so don't block. 7641da177e4SLinus Torvalds */ 7651da177e4SLinus Torvalds static void copy_callback(int read_err, unsigned int write_err, void *context) 7661da177e4SLinus Torvalds { 767028867acSAlasdair G Kergon struct dm_snap_pending_exception *pe = context; 7681da177e4SLinus Torvalds struct dm_snapshot *s = pe->snap; 7691da177e4SLinus Torvalds 7701da177e4SLinus Torvalds if (read_err || write_err) 7711da177e4SLinus Torvalds pending_complete(pe, 0); 7721da177e4SLinus Torvalds 7731da177e4SLinus Torvalds else 7741da177e4SLinus Torvalds /* Update the metadata if we are persistent */ 7751da177e4SLinus Torvalds s->store.commit_exception(&s->store, &pe->e, commit_callback, 7761da177e4SLinus Torvalds pe); 7771da177e4SLinus Torvalds } 7781da177e4SLinus Torvalds 7791da177e4SLinus Torvalds /* 7801da177e4SLinus Torvalds * Dispatches the copy operation to kcopyd. 7811da177e4SLinus Torvalds */ 782028867acSAlasdair G Kergon static void start_copy(struct dm_snap_pending_exception *pe) 7831da177e4SLinus Torvalds { 7841da177e4SLinus Torvalds struct dm_snapshot *s = pe->snap; 7851da177e4SLinus Torvalds struct io_region src, dest; 7861da177e4SLinus Torvalds struct block_device *bdev = s->origin->bdev; 7871da177e4SLinus Torvalds sector_t dev_size; 7881da177e4SLinus Torvalds 7891da177e4SLinus Torvalds dev_size = get_dev_size(bdev); 7901da177e4SLinus Torvalds 7911da177e4SLinus Torvalds src.bdev = bdev; 7921da177e4SLinus Torvalds src.sector = chunk_to_sector(s, pe->e.old_chunk); 7931da177e4SLinus Torvalds src.count = min(s->chunk_size, dev_size - src.sector); 7941da177e4SLinus Torvalds 7951da177e4SLinus Torvalds dest.bdev = s->cow->bdev; 7961da177e4SLinus Torvalds dest.sector = chunk_to_sector(s, pe->e.new_chunk); 7971da177e4SLinus Torvalds dest.count = src.count; 7981da177e4SLinus Torvalds 7991da177e4SLinus Torvalds /* Hand over to kcopyd */ 8001da177e4SLinus Torvalds kcopyd_copy(s->kcopyd_client, 8011da177e4SLinus Torvalds &src, 1, &dest, 0, copy_callback, pe); 8021da177e4SLinus Torvalds } 8031da177e4SLinus Torvalds 8041da177e4SLinus Torvalds /* 8051da177e4SLinus Torvalds * Looks to see if this snapshot already has a pending exception 8061da177e4SLinus Torvalds * for this chunk, otherwise it allocates a new one and inserts 8071da177e4SLinus Torvalds * it into the pending table. 8081da177e4SLinus Torvalds * 8091da177e4SLinus Torvalds * NOTE: a write lock must be held on snap->lock before calling 8101da177e4SLinus Torvalds * this. 8111da177e4SLinus Torvalds */ 812028867acSAlasdair G Kergon static struct dm_snap_pending_exception * 8131da177e4SLinus Torvalds __find_pending_exception(struct dm_snapshot *s, struct bio *bio) 8141da177e4SLinus Torvalds { 815028867acSAlasdair G Kergon struct dm_snap_exception *e; 816028867acSAlasdair G Kergon struct dm_snap_pending_exception *pe; 8171da177e4SLinus Torvalds chunk_t chunk = sector_to_chunk(s, bio->bi_sector); 8181da177e4SLinus Torvalds 8191da177e4SLinus Torvalds /* 8201da177e4SLinus Torvalds * Is there a pending exception for this already ? 8211da177e4SLinus Torvalds */ 8221da177e4SLinus Torvalds e = lookup_exception(&s->pending, chunk); 8231da177e4SLinus Torvalds if (e) { 8241da177e4SLinus Torvalds /* cast the exception to a pending exception */ 825028867acSAlasdair G Kergon pe = container_of(e, struct dm_snap_pending_exception, e); 82676df1c65SAlasdair G Kergon goto out; 82776df1c65SAlasdair G Kergon } 8281da177e4SLinus Torvalds 8291da177e4SLinus Torvalds /* 8301da177e4SLinus Torvalds * Create a new pending exception, we don't want 8311da177e4SLinus Torvalds * to hold the lock while we do this. 8321da177e4SLinus Torvalds */ 8331da177e4SLinus Torvalds up_write(&s->lock); 8341da177e4SLinus Torvalds pe = alloc_pending_exception(); 8351da177e4SLinus Torvalds down_write(&s->lock); 8361da177e4SLinus Torvalds 83776df1c65SAlasdair G Kergon if (!s->valid) { 83876df1c65SAlasdair G Kergon free_pending_exception(pe); 83976df1c65SAlasdair G Kergon return NULL; 84076df1c65SAlasdair G Kergon } 84176df1c65SAlasdair G Kergon 8421da177e4SLinus Torvalds e = lookup_exception(&s->pending, chunk); 8431da177e4SLinus Torvalds if (e) { 8441da177e4SLinus Torvalds free_pending_exception(pe); 845028867acSAlasdair G Kergon pe = container_of(e, struct dm_snap_pending_exception, e); 84676df1c65SAlasdair G Kergon goto out; 84776df1c65SAlasdair G Kergon } 84876df1c65SAlasdair G Kergon 8491da177e4SLinus Torvalds pe->e.old_chunk = chunk; 8501da177e4SLinus Torvalds bio_list_init(&pe->origin_bios); 8511da177e4SLinus Torvalds bio_list_init(&pe->snapshot_bios); 852b4b610f6SAlasdair G Kergon pe->primary_pe = NULL; 8534b832e8dSAlasdair G Kergon atomic_set(&pe->ref_count, 0); 8541da177e4SLinus Torvalds pe->snap = s; 8551da177e4SLinus Torvalds pe->started = 0; 8561da177e4SLinus Torvalds 8571da177e4SLinus Torvalds if (s->store.prepare_exception(&s->store, &pe->e)) { 8581da177e4SLinus Torvalds free_pending_exception(pe); 8591da177e4SLinus Torvalds return NULL; 8601da177e4SLinus Torvalds } 8611da177e4SLinus Torvalds 8624b832e8dSAlasdair G Kergon get_pending_exception(pe); 8631da177e4SLinus Torvalds insert_exception(&s->pending, &pe->e); 8641da177e4SLinus Torvalds 86576df1c65SAlasdair G Kergon out: 8661da177e4SLinus Torvalds return pe; 8671da177e4SLinus Torvalds } 8681da177e4SLinus Torvalds 869028867acSAlasdair G Kergon static void remap_exception(struct dm_snapshot *s, struct dm_snap_exception *e, 8701da177e4SLinus Torvalds struct bio *bio) 8711da177e4SLinus Torvalds { 8721da177e4SLinus Torvalds bio->bi_bdev = s->cow->bdev; 8731da177e4SLinus Torvalds bio->bi_sector = chunk_to_sector(s, e->new_chunk) + 8741da177e4SLinus Torvalds (bio->bi_sector & s->chunk_mask); 8751da177e4SLinus Torvalds } 8761da177e4SLinus Torvalds 8771da177e4SLinus Torvalds static int snapshot_map(struct dm_target *ti, struct bio *bio, 8781da177e4SLinus Torvalds union map_info *map_context) 8791da177e4SLinus Torvalds { 880028867acSAlasdair G Kergon struct dm_snap_exception *e; 881028867acSAlasdair G Kergon struct dm_snapshot *s = ti->private; 882d2a7ad29SKiyoshi Ueda int r = DM_MAPIO_REMAPPED; 8831da177e4SLinus Torvalds chunk_t chunk; 884028867acSAlasdair G Kergon struct dm_snap_pending_exception *pe = NULL; 8851da177e4SLinus Torvalds 8861da177e4SLinus Torvalds chunk = sector_to_chunk(s, bio->bi_sector); 8871da177e4SLinus Torvalds 8881da177e4SLinus Torvalds /* Full snapshots are not usable */ 88976df1c65SAlasdair G Kergon /* To get here the table must be live so s->active is always set. */ 8901da177e4SLinus Torvalds if (!s->valid) 891f6a80ea8SAlasdair G Kergon return -EIO; 8921da177e4SLinus Torvalds 8931da177e4SLinus Torvalds /* FIXME: should only take write lock if we need 8941da177e4SLinus Torvalds * to copy an exception */ 8951da177e4SLinus Torvalds down_write(&s->lock); 8961da177e4SLinus Torvalds 89776df1c65SAlasdair G Kergon if (!s->valid) { 89876df1c65SAlasdair G Kergon r = -EIO; 89976df1c65SAlasdair G Kergon goto out_unlock; 90076df1c65SAlasdair G Kergon } 90176df1c65SAlasdair G Kergon 9021da177e4SLinus Torvalds /* If the block is already remapped - use that, else remap it */ 9031da177e4SLinus Torvalds e = lookup_exception(&s->complete, chunk); 9041da177e4SLinus Torvalds if (e) { 9051da177e4SLinus Torvalds remap_exception(s, e, bio); 90676df1c65SAlasdair G Kergon goto out_unlock; 90776df1c65SAlasdair G Kergon } 9081da177e4SLinus Torvalds 909ba40a2aaSAlasdair G Kergon /* 910ba40a2aaSAlasdair G Kergon * Write to snapshot - higher level takes care of RW/RO 911ba40a2aaSAlasdair G Kergon * flags so we should only get this if we are 912ba40a2aaSAlasdair G Kergon * writeable. 913ba40a2aaSAlasdair G Kergon */ 914ba40a2aaSAlasdair G Kergon if (bio_rw(bio) == WRITE) { 9151da177e4SLinus Torvalds pe = __find_pending_exception(s, bio); 9161da177e4SLinus Torvalds if (!pe) { 917695368acSAlasdair G Kergon __invalidate_snapshot(s, -ENOMEM); 9181da177e4SLinus Torvalds r = -EIO; 91976df1c65SAlasdair G Kergon goto out_unlock; 92076df1c65SAlasdair G Kergon } 92176df1c65SAlasdair G Kergon 9221da177e4SLinus Torvalds remap_exception(s, &pe->e, bio); 9231da177e4SLinus Torvalds bio_list_add(&pe->snapshot_bios, bio); 9241da177e4SLinus Torvalds 925d2a7ad29SKiyoshi Ueda r = DM_MAPIO_SUBMITTED; 926ba40a2aaSAlasdair G Kergon 9271da177e4SLinus Torvalds if (!pe->started) { 9281da177e4SLinus Torvalds /* this is protected by snap->lock */ 9291da177e4SLinus Torvalds pe->started = 1; 93076df1c65SAlasdair G Kergon up_write(&s->lock); 93176df1c65SAlasdair G Kergon start_copy(pe); 932ba40a2aaSAlasdair G Kergon goto out; 933ba40a2aaSAlasdair G Kergon } 934ba40a2aaSAlasdair G Kergon } else 9351da177e4SLinus Torvalds /* 9361da177e4SLinus Torvalds * FIXME: this read path scares me because we 9371da177e4SLinus Torvalds * always use the origin when we have a pending 9381da177e4SLinus Torvalds * exception. However I can't think of a 9391da177e4SLinus Torvalds * situation where this is wrong - ejt. 9401da177e4SLinus Torvalds */ 9411da177e4SLinus Torvalds bio->bi_bdev = s->origin->bdev; 9421da177e4SLinus Torvalds 943ba40a2aaSAlasdair G Kergon out_unlock: 944ba40a2aaSAlasdair G Kergon up_write(&s->lock); 945ba40a2aaSAlasdair G Kergon out: 9461da177e4SLinus Torvalds return r; 9471da177e4SLinus Torvalds } 9481da177e4SLinus Torvalds 9491da177e4SLinus Torvalds static void snapshot_resume(struct dm_target *ti) 9501da177e4SLinus Torvalds { 951028867acSAlasdair G Kergon struct dm_snapshot *s = ti->private; 9521da177e4SLinus Torvalds 953aa14edebSAlasdair G Kergon down_write(&s->lock); 954aa14edebSAlasdair G Kergon s->active = 1; 955aa14edebSAlasdair G Kergon up_write(&s->lock); 9561da177e4SLinus Torvalds } 9571da177e4SLinus Torvalds 9581da177e4SLinus Torvalds static int snapshot_status(struct dm_target *ti, status_type_t type, 9591da177e4SLinus Torvalds char *result, unsigned int maxlen) 9601da177e4SLinus Torvalds { 961028867acSAlasdair G Kergon struct dm_snapshot *snap = ti->private; 9621da177e4SLinus Torvalds 9631da177e4SLinus Torvalds switch (type) { 9641da177e4SLinus Torvalds case STATUSTYPE_INFO: 9651da177e4SLinus Torvalds if (!snap->valid) 9661da177e4SLinus Torvalds snprintf(result, maxlen, "Invalid"); 9671da177e4SLinus Torvalds else { 9681da177e4SLinus Torvalds if (snap->store.fraction_full) { 9691da177e4SLinus Torvalds sector_t numerator, denominator; 9701da177e4SLinus Torvalds snap->store.fraction_full(&snap->store, 9711da177e4SLinus Torvalds &numerator, 9721da177e4SLinus Torvalds &denominator); 9734ee218cdSAndrew Morton snprintf(result, maxlen, "%llu/%llu", 9744ee218cdSAndrew Morton (unsigned long long)numerator, 9754ee218cdSAndrew Morton (unsigned long long)denominator); 9761da177e4SLinus Torvalds } 9771da177e4SLinus Torvalds else 9781da177e4SLinus Torvalds snprintf(result, maxlen, "Unknown"); 9791da177e4SLinus Torvalds } 9801da177e4SLinus Torvalds break; 9811da177e4SLinus Torvalds 9821da177e4SLinus Torvalds case STATUSTYPE_TABLE: 9831da177e4SLinus Torvalds /* 9841da177e4SLinus Torvalds * kdevname returns a static pointer so we need 9851da177e4SLinus Torvalds * to make private copies if the output is to 9861da177e4SLinus Torvalds * make sense. 9871da177e4SLinus Torvalds */ 9884ee218cdSAndrew Morton snprintf(result, maxlen, "%s %s %c %llu", 9891da177e4SLinus Torvalds snap->origin->name, snap->cow->name, 9904ee218cdSAndrew Morton snap->type, 9914ee218cdSAndrew Morton (unsigned long long)snap->chunk_size); 9921da177e4SLinus Torvalds break; 9931da177e4SLinus Torvalds } 9941da177e4SLinus Torvalds 9951da177e4SLinus Torvalds return 0; 9961da177e4SLinus Torvalds } 9971da177e4SLinus Torvalds 9981da177e4SLinus Torvalds /*----------------------------------------------------------------- 9991da177e4SLinus Torvalds * Origin methods 10001da177e4SLinus Torvalds *---------------------------------------------------------------*/ 10011da177e4SLinus Torvalds static int __origin_write(struct list_head *snapshots, struct bio *bio) 10021da177e4SLinus Torvalds { 1003d2a7ad29SKiyoshi Ueda int r = DM_MAPIO_REMAPPED, first = 0; 10041da177e4SLinus Torvalds struct dm_snapshot *snap; 1005028867acSAlasdair G Kergon struct dm_snap_exception *e; 1006028867acSAlasdair G Kergon struct dm_snap_pending_exception *pe, *next_pe, *primary_pe = NULL; 10071da177e4SLinus Torvalds chunk_t chunk; 1008eccf0817SAlasdair G Kergon LIST_HEAD(pe_queue); 10091da177e4SLinus Torvalds 10101da177e4SLinus Torvalds /* Do all the snapshots on this origin */ 10111da177e4SLinus Torvalds list_for_each_entry (snap, snapshots, list) { 10121da177e4SLinus Torvalds 101376df1c65SAlasdair G Kergon down_write(&snap->lock); 101476df1c65SAlasdair G Kergon 1015aa14edebSAlasdair G Kergon /* Only deal with valid and active snapshots */ 1016aa14edebSAlasdair G Kergon if (!snap->valid || !snap->active) 101776df1c65SAlasdair G Kergon goto next_snapshot; 10181da177e4SLinus Torvalds 1019d5e404c1SAlasdair G Kergon /* Nothing to do if writing beyond end of snapshot */ 1020d5e404c1SAlasdair G Kergon if (bio->bi_sector >= dm_table_get_size(snap->table)) 102176df1c65SAlasdair G Kergon goto next_snapshot; 10221da177e4SLinus Torvalds 10231da177e4SLinus Torvalds /* 10241da177e4SLinus Torvalds * Remember, different snapshots can have 10251da177e4SLinus Torvalds * different chunk sizes. 10261da177e4SLinus Torvalds */ 10271da177e4SLinus Torvalds chunk = sector_to_chunk(snap, bio->bi_sector); 10281da177e4SLinus Torvalds 10291da177e4SLinus Torvalds /* 10301da177e4SLinus Torvalds * Check exception table to see if block 10311da177e4SLinus Torvalds * is already remapped in this snapshot 10321da177e4SLinus Torvalds * and trigger an exception if not. 1033b4b610f6SAlasdair G Kergon * 10344b832e8dSAlasdair G Kergon * ref_count is initialised to 1 so pending_complete() 1035b4b610f6SAlasdair G Kergon * won't destroy the primary_pe while we're inside this loop. 10361da177e4SLinus Torvalds */ 10371da177e4SLinus Torvalds e = lookup_exception(&snap->complete, chunk); 103876df1c65SAlasdair G Kergon if (e) 103976df1c65SAlasdair G Kergon goto next_snapshot; 104076df1c65SAlasdair G Kergon 10411da177e4SLinus Torvalds pe = __find_pending_exception(snap, bio); 10421da177e4SLinus Torvalds if (!pe) { 1043695368acSAlasdair G Kergon __invalidate_snapshot(snap, -ENOMEM); 104476df1c65SAlasdair G Kergon goto next_snapshot; 104576df1c65SAlasdair G Kergon } 10461da177e4SLinus Torvalds 1047b4b610f6SAlasdair G Kergon if (!primary_pe) { 1048b4b610f6SAlasdair G Kergon /* 1049b4b610f6SAlasdair G Kergon * Either every pe here has same 1050b4b610f6SAlasdair G Kergon * primary_pe or none has one yet. 1051b4b610f6SAlasdair G Kergon */ 1052b4b610f6SAlasdair G Kergon if (pe->primary_pe) 1053b4b610f6SAlasdair G Kergon primary_pe = pe->primary_pe; 1054b4b610f6SAlasdair G Kergon else { 1055b4b610f6SAlasdair G Kergon primary_pe = pe; 1056b4b610f6SAlasdair G Kergon first = 1; 1057eccf0817SAlasdair G Kergon } 1058b4b610f6SAlasdair G Kergon 105976df1c65SAlasdair G Kergon bio_list_add(&primary_pe->origin_bios, bio); 106076df1c65SAlasdair G Kergon 1061d2a7ad29SKiyoshi Ueda r = DM_MAPIO_SUBMITTED; 1062b4b610f6SAlasdair G Kergon } 106376df1c65SAlasdair G Kergon 1064b4b610f6SAlasdair G Kergon if (!pe->primary_pe) { 1065b4b610f6SAlasdair G Kergon pe->primary_pe = primary_pe; 10664b832e8dSAlasdair G Kergon get_pending_exception(primary_pe); 1067b4b610f6SAlasdair G Kergon } 106876df1c65SAlasdair G Kergon 1069eccf0817SAlasdair G Kergon if (!pe->started) { 1070eccf0817SAlasdair G Kergon pe->started = 1; 1071eccf0817SAlasdair G Kergon list_add_tail(&pe->list, &pe_queue); 1072eccf0817SAlasdair G Kergon } 10731da177e4SLinus Torvalds 107476df1c65SAlasdair G Kergon next_snapshot: 10751da177e4SLinus Torvalds up_write(&snap->lock); 10761da177e4SLinus Torvalds } 10771da177e4SLinus Torvalds 1078b4b610f6SAlasdair G Kergon if (!primary_pe) 10794b832e8dSAlasdair G Kergon return r; 1080b4b610f6SAlasdair G Kergon 1081b4b610f6SAlasdair G Kergon /* 1082b4b610f6SAlasdair G Kergon * If this is the first time we're processing this chunk and 10834b832e8dSAlasdair G Kergon * ref_count is now 1 it means all the pending exceptions 1084b4b610f6SAlasdair G Kergon * got completed while we were in the loop above, so it falls to 1085b4b610f6SAlasdair G Kergon * us here to remove the primary_pe and submit any origin_bios. 1086b4b610f6SAlasdair G Kergon */ 1087b4b610f6SAlasdair G Kergon 10884b832e8dSAlasdair G Kergon if (first && atomic_dec_and_test(&primary_pe->ref_count)) { 1089b4b610f6SAlasdair G Kergon flush_bios(bio_list_get(&primary_pe->origin_bios)); 1090b4b610f6SAlasdair G Kergon free_pending_exception(primary_pe); 1091b4b610f6SAlasdair G Kergon /* If we got here, pe_queue is necessarily empty. */ 10924b832e8dSAlasdair G Kergon return r; 1093b4b610f6SAlasdair G Kergon } 1094b4b610f6SAlasdair G Kergon 10951da177e4SLinus Torvalds /* 10961da177e4SLinus Torvalds * Now that we have a complete pe list we can start the copying. 10971da177e4SLinus Torvalds */ 1098eccf0817SAlasdair G Kergon list_for_each_entry_safe(pe, next_pe, &pe_queue, list) 10991da177e4SLinus Torvalds start_copy(pe); 11001da177e4SLinus Torvalds 11011da177e4SLinus Torvalds return r; 11021da177e4SLinus Torvalds } 11031da177e4SLinus Torvalds 11041da177e4SLinus Torvalds /* 11051da177e4SLinus Torvalds * Called on a write from the origin driver. 11061da177e4SLinus Torvalds */ 11071da177e4SLinus Torvalds static int do_origin(struct dm_dev *origin, struct bio *bio) 11081da177e4SLinus Torvalds { 11091da177e4SLinus Torvalds struct origin *o; 1110d2a7ad29SKiyoshi Ueda int r = DM_MAPIO_REMAPPED; 11111da177e4SLinus Torvalds 11121da177e4SLinus Torvalds down_read(&_origins_lock); 11131da177e4SLinus Torvalds o = __lookup_origin(origin->bdev); 11141da177e4SLinus Torvalds if (o) 11151da177e4SLinus Torvalds r = __origin_write(&o->snapshots, bio); 11161da177e4SLinus Torvalds up_read(&_origins_lock); 11171da177e4SLinus Torvalds 11181da177e4SLinus Torvalds return r; 11191da177e4SLinus Torvalds } 11201da177e4SLinus Torvalds 11211da177e4SLinus Torvalds /* 11221da177e4SLinus Torvalds * Origin: maps a linear range of a device, with hooks for snapshotting. 11231da177e4SLinus Torvalds */ 11241da177e4SLinus Torvalds 11251da177e4SLinus Torvalds /* 11261da177e4SLinus Torvalds * Construct an origin mapping: <dev_path> 11271da177e4SLinus Torvalds * The context for an origin is merely a 'struct dm_dev *' 11281da177e4SLinus Torvalds * pointing to the real device. 11291da177e4SLinus Torvalds */ 11301da177e4SLinus Torvalds static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv) 11311da177e4SLinus Torvalds { 11321da177e4SLinus Torvalds int r; 11331da177e4SLinus Torvalds struct dm_dev *dev; 11341da177e4SLinus Torvalds 11351da177e4SLinus Torvalds if (argc != 1) { 113672d94861SAlasdair G Kergon ti->error = "origin: incorrect number of arguments"; 11371da177e4SLinus Torvalds return -EINVAL; 11381da177e4SLinus Torvalds } 11391da177e4SLinus Torvalds 11401da177e4SLinus Torvalds r = dm_get_device(ti, argv[0], 0, ti->len, 11411da177e4SLinus Torvalds dm_table_get_mode(ti->table), &dev); 11421da177e4SLinus Torvalds if (r) { 11431da177e4SLinus Torvalds ti->error = "Cannot get target device"; 11441da177e4SLinus Torvalds return r; 11451da177e4SLinus Torvalds } 11461da177e4SLinus Torvalds 11471da177e4SLinus Torvalds ti->private = dev; 11481da177e4SLinus Torvalds return 0; 11491da177e4SLinus Torvalds } 11501da177e4SLinus Torvalds 11511da177e4SLinus Torvalds static void origin_dtr(struct dm_target *ti) 11521da177e4SLinus Torvalds { 1153028867acSAlasdair G Kergon struct dm_dev *dev = ti->private; 11541da177e4SLinus Torvalds dm_put_device(ti, dev); 11551da177e4SLinus Torvalds } 11561da177e4SLinus Torvalds 11571da177e4SLinus Torvalds static int origin_map(struct dm_target *ti, struct bio *bio, 11581da177e4SLinus Torvalds union map_info *map_context) 11591da177e4SLinus Torvalds { 1160028867acSAlasdair G Kergon struct dm_dev *dev = ti->private; 11611da177e4SLinus Torvalds bio->bi_bdev = dev->bdev; 11621da177e4SLinus Torvalds 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 { 1175028867acSAlasdair G Kergon struct dm_dev *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 { 1193028867acSAlasdair G Kergon struct dm_dev *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 1252028867acSAlasdair G Kergon exception_cache = KMEM_CACHE(dm_snap_exception, 0); 12531da177e4SLinus Torvalds if (!exception_cache) { 12541da177e4SLinus Torvalds DMERR("Couldn't create exception cache."); 12551da177e4SLinus Torvalds r = -ENOMEM; 12561da177e4SLinus Torvalds goto bad3; 12571da177e4SLinus Torvalds } 12581da177e4SLinus Torvalds 1259028867acSAlasdair G Kergon pending_cache = KMEM_CACHE(dm_snap_pending_exception, 0); 12601da177e4SLinus Torvalds if (!pending_cache) { 12611da177e4SLinus Torvalds DMERR("Couldn't create pending cache."); 12621da177e4SLinus Torvalds r = -ENOMEM; 12631da177e4SLinus Torvalds goto bad4; 12641da177e4SLinus Torvalds } 12651da177e4SLinus Torvalds 126693d2341cSMatthew Dobson pending_pool = mempool_create_slab_pool(128, pending_cache); 12671da177e4SLinus Torvalds if (!pending_pool) { 12681da177e4SLinus Torvalds DMERR("Couldn't create pending pool."); 12691da177e4SLinus Torvalds r = -ENOMEM; 12701da177e4SLinus Torvalds goto bad5; 12711da177e4SLinus Torvalds } 12721da177e4SLinus Torvalds 1273ca3a931fSAlasdair G Kergon ksnapd = create_singlethread_workqueue("ksnapd"); 1274ca3a931fSAlasdair G Kergon if (!ksnapd) { 1275ca3a931fSAlasdair G Kergon DMERR("Failed to create ksnapd workqueue."); 1276ca3a931fSAlasdair G Kergon r = -ENOMEM; 1277ca3a931fSAlasdair G Kergon goto bad6; 1278ca3a931fSAlasdair G Kergon } 1279ca3a931fSAlasdair G Kergon 12801da177e4SLinus Torvalds return 0; 12811da177e4SLinus Torvalds 1282ca3a931fSAlasdair G Kergon bad6: 1283ca3a931fSAlasdair G Kergon mempool_destroy(pending_pool); 12841da177e4SLinus Torvalds bad5: 12851da177e4SLinus Torvalds kmem_cache_destroy(pending_cache); 12861da177e4SLinus Torvalds bad4: 12871da177e4SLinus Torvalds kmem_cache_destroy(exception_cache); 12881da177e4SLinus Torvalds bad3: 12891da177e4SLinus Torvalds exit_origin_hash(); 12901da177e4SLinus Torvalds bad2: 12911da177e4SLinus Torvalds dm_unregister_target(&origin_target); 12921da177e4SLinus Torvalds bad1: 12931da177e4SLinus Torvalds dm_unregister_target(&snapshot_target); 12941da177e4SLinus Torvalds return r; 12951da177e4SLinus Torvalds } 12961da177e4SLinus Torvalds 12971da177e4SLinus Torvalds static void __exit dm_snapshot_exit(void) 12981da177e4SLinus Torvalds { 12991da177e4SLinus Torvalds int r; 13001da177e4SLinus Torvalds 1301ca3a931fSAlasdair G Kergon destroy_workqueue(ksnapd); 1302ca3a931fSAlasdair G Kergon 13031da177e4SLinus Torvalds r = dm_unregister_target(&snapshot_target); 13041da177e4SLinus Torvalds if (r) 13051da177e4SLinus Torvalds DMERR("snapshot unregister failed %d", r); 13061da177e4SLinus Torvalds 13071da177e4SLinus Torvalds r = dm_unregister_target(&origin_target); 13081da177e4SLinus Torvalds if (r) 13091da177e4SLinus Torvalds DMERR("origin unregister failed %d", r); 13101da177e4SLinus Torvalds 13111da177e4SLinus Torvalds exit_origin_hash(); 13121da177e4SLinus Torvalds mempool_destroy(pending_pool); 13131da177e4SLinus Torvalds kmem_cache_destroy(pending_cache); 13141da177e4SLinus Torvalds kmem_cache_destroy(exception_cache); 13151da177e4SLinus Torvalds } 13161da177e4SLinus Torvalds 13171da177e4SLinus Torvalds /* Module hooks */ 13181da177e4SLinus Torvalds module_init(dm_snapshot_init); 13191da177e4SLinus Torvalds module_exit(dm_snapshot_exit); 13201da177e4SLinus Torvalds 13211da177e4SLinus Torvalds MODULE_DESCRIPTION(DM_NAME " snapshot target"); 13221da177e4SLinus Torvalds MODULE_AUTHOR("Joe Thornber"); 13231da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 1324