14db6bfe0SAlasdair G Kergon /* 24db6bfe0SAlasdair G Kergon * Copyright (C) 2001-2002 Sistina Software (UK) Limited. 34db6bfe0SAlasdair G Kergon * Copyright (C) 2006-2008 Red Hat GmbH 44db6bfe0SAlasdair G Kergon * 54db6bfe0SAlasdair G Kergon * This file is released under the GPL. 64db6bfe0SAlasdair G Kergon */ 74db6bfe0SAlasdair G Kergon 84db6bfe0SAlasdair G Kergon #include "dm-exception-store.h" 94db6bfe0SAlasdair G Kergon 104db6bfe0SAlasdair G Kergon #include <linux/mm.h> 114db6bfe0SAlasdair G Kergon #include <linux/pagemap.h> 124db6bfe0SAlasdair G Kergon #include <linux/vmalloc.h> 134db6bfe0SAlasdair G Kergon #include <linux/slab.h> 144db6bfe0SAlasdair G Kergon #include <linux/dm-io.h> 154db6bfe0SAlasdair G Kergon 164db6bfe0SAlasdair G Kergon #define DM_MSG_PREFIX "transient snapshot" 174db6bfe0SAlasdair G Kergon 184db6bfe0SAlasdair G Kergon /*----------------------------------------------------------------- 194db6bfe0SAlasdair G Kergon * Implementation of the store for non-persistent snapshots. 204db6bfe0SAlasdair G Kergon *---------------------------------------------------------------*/ 214db6bfe0SAlasdair G Kergon struct transient_c { 224db6bfe0SAlasdair G Kergon sector_t next_free; 234db6bfe0SAlasdair G Kergon }; 244db6bfe0SAlasdair G Kergon 25493df71cSJonathan Brassow static void transient_dtr(struct dm_exception_store *store) 264db6bfe0SAlasdair G Kergon { 274db6bfe0SAlasdair G Kergon kfree(store->context); 284db6bfe0SAlasdair G Kergon } 294db6bfe0SAlasdair G Kergon 30a159c1acSJonathan Brassow static int transient_read_metadata(struct dm_exception_store *store, 31a159c1acSJonathan Brassow int (*callback)(void *callback_context, 32a159c1acSJonathan Brassow chunk_t old, chunk_t new), 33a159c1acSJonathan Brassow void *callback_context) 344db6bfe0SAlasdair G Kergon { 354db6bfe0SAlasdair G Kergon return 0; 364db6bfe0SAlasdair G Kergon } 374db6bfe0SAlasdair G Kergon 38a159c1acSJonathan Brassow static int transient_prepare_exception(struct dm_exception_store *store, 391d4989c8SJon Brassow struct dm_exception *e) 404db6bfe0SAlasdair G Kergon { 41b2a11465SJonathan Brassow struct transient_c *tc = store->context; 4249beb2b8SJonathan Brassow sector_t size = get_dev_size(store->cow->bdev); 434db6bfe0SAlasdair G Kergon 44d0216849SJonathan Brassow if (size < (tc->next_free + store->chunk_size)) 454db6bfe0SAlasdair G Kergon return -1; 464db6bfe0SAlasdair G Kergon 4771fab00aSJonathan Brassow e->new_chunk = sector_to_chunk(store, tc->next_free); 48d0216849SJonathan Brassow tc->next_free += store->chunk_size; 494db6bfe0SAlasdair G Kergon 504db6bfe0SAlasdair G Kergon return 0; 514db6bfe0SAlasdair G Kergon } 524db6bfe0SAlasdair G Kergon 53a159c1acSJonathan Brassow static void transient_commit_exception(struct dm_exception_store *store, 541d4989c8SJon Brassow struct dm_exception *e, 554db6bfe0SAlasdair G Kergon void (*callback) (void *, int success), 564db6bfe0SAlasdair G Kergon void *callback_context) 574db6bfe0SAlasdair G Kergon { 584db6bfe0SAlasdair G Kergon /* Just succeed */ 594db6bfe0SAlasdair G Kergon callback(callback_context, 1); 604db6bfe0SAlasdair G Kergon } 614db6bfe0SAlasdair G Kergon 62985903bbSMike Snitzer static void transient_usage(struct dm_exception_store *store, 63985903bbSMike Snitzer sector_t *total_sectors, 64985903bbSMike Snitzer sector_t *sectors_allocated, 65985903bbSMike Snitzer sector_t *metadata_sectors) 664db6bfe0SAlasdair G Kergon { 67985903bbSMike Snitzer *sectors_allocated = ((struct transient_c *) store->context)->next_free; 68985903bbSMike Snitzer *total_sectors = get_dev_size(store->cow->bdev); 69985903bbSMike Snitzer *metadata_sectors = 0; 704db6bfe0SAlasdair G Kergon } 714db6bfe0SAlasdair G Kergon 72493df71cSJonathan Brassow static int transient_ctr(struct dm_exception_store *store, 73493df71cSJonathan Brassow unsigned argc, char **argv) 744db6bfe0SAlasdair G Kergon { 754db6bfe0SAlasdair G Kergon struct transient_c *tc; 764db6bfe0SAlasdair G Kergon 774db6bfe0SAlasdair G Kergon tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL); 784db6bfe0SAlasdair G Kergon if (!tc) 794db6bfe0SAlasdair G Kergon return -ENOMEM; 804db6bfe0SAlasdair G Kergon 814db6bfe0SAlasdair G Kergon tc->next_free = 0; 824db6bfe0SAlasdair G Kergon store->context = tc; 834db6bfe0SAlasdair G Kergon 844db6bfe0SAlasdair G Kergon return 0; 854db6bfe0SAlasdair G Kergon } 864db6bfe0SAlasdair G Kergon 871e302a92SJonathan Brassow static unsigned transient_status(struct dm_exception_store *store, 88493df71cSJonathan Brassow status_type_t status, char *result, 89493df71cSJonathan Brassow unsigned maxlen) 90493df71cSJonathan Brassow { 911e302a92SJonathan Brassow unsigned sz = 0; 921e302a92SJonathan Brassow 931e302a92SJonathan Brassow switch (status) { 941e302a92SJonathan Brassow case STATUSTYPE_INFO: 951e302a92SJonathan Brassow break; 961e302a92SJonathan Brassow case STATUSTYPE_TABLE: 971e302a92SJonathan Brassow DMEMIT(" %s N %llu", store->cow->name, 981e302a92SJonathan Brassow (unsigned long long)store->chunk_size); 991e302a92SJonathan Brassow } 100493df71cSJonathan Brassow 101493df71cSJonathan Brassow return sz; 102493df71cSJonathan Brassow } 103493df71cSJonathan Brassow 104493df71cSJonathan Brassow static struct dm_exception_store_type _transient_type = { 105493df71cSJonathan Brassow .name = "transient", 106493df71cSJonathan Brassow .module = THIS_MODULE, 107493df71cSJonathan Brassow .ctr = transient_ctr, 108493df71cSJonathan Brassow .dtr = transient_dtr, 109493df71cSJonathan Brassow .read_metadata = transient_read_metadata, 110493df71cSJonathan Brassow .prepare_exception = transient_prepare_exception, 111493df71cSJonathan Brassow .commit_exception = transient_commit_exception, 112985903bbSMike Snitzer .usage = transient_usage, 113493df71cSJonathan Brassow .status = transient_status, 114493df71cSJonathan Brassow }; 115493df71cSJonathan Brassow 116493df71cSJonathan Brassow static struct dm_exception_store_type _transient_compat_type = { 117493df71cSJonathan Brassow .name = "N", 118493df71cSJonathan Brassow .module = THIS_MODULE, 119493df71cSJonathan Brassow .ctr = transient_ctr, 120493df71cSJonathan Brassow .dtr = transient_dtr, 121493df71cSJonathan Brassow .read_metadata = transient_read_metadata, 122493df71cSJonathan Brassow .prepare_exception = transient_prepare_exception, 123493df71cSJonathan Brassow .commit_exception = transient_commit_exception, 124985903bbSMike Snitzer .usage = transient_usage, 125493df71cSJonathan Brassow .status = transient_status, 126493df71cSJonathan Brassow }; 127493df71cSJonathan Brassow 1284db6bfe0SAlasdair G Kergon int dm_transient_snapshot_init(void) 1294db6bfe0SAlasdair G Kergon { 130493df71cSJonathan Brassow int r; 131493df71cSJonathan Brassow 132493df71cSJonathan Brassow r = dm_exception_store_type_register(&_transient_type); 133493df71cSJonathan Brassow if (r) { 134493df71cSJonathan Brassow DMWARN("Unable to register transient exception store type"); 135493df71cSJonathan Brassow return r; 136493df71cSJonathan Brassow } 137493df71cSJonathan Brassow 138493df71cSJonathan Brassow r = dm_exception_store_type_register(&_transient_compat_type); 139493df71cSJonathan Brassow if (r) { 140493df71cSJonathan Brassow DMWARN("Unable to register old-style transient " 141493df71cSJonathan Brassow "exception store type"); 142493df71cSJonathan Brassow dm_exception_store_type_unregister(&_transient_type); 143493df71cSJonathan Brassow return r; 144493df71cSJonathan Brassow } 145493df71cSJonathan Brassow 146493df71cSJonathan Brassow return r; 1474db6bfe0SAlasdair G Kergon } 1484db6bfe0SAlasdair G Kergon 1494db6bfe0SAlasdair G Kergon void dm_transient_snapshot_exit(void) 1504db6bfe0SAlasdair G Kergon { 151493df71cSJonathan Brassow dm_exception_store_type_unregister(&_transient_type); 152493df71cSJonathan Brassow dm_exception_store_type_unregister(&_transient_compat_type); 1534db6bfe0SAlasdair G Kergon } 154