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, 394db6bfe0SAlasdair G Kergon struct dm_snap_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, 544db6bfe0SAlasdair G Kergon struct dm_snap_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 624db6bfe0SAlasdair G Kergon static void transient_fraction_full(struct dm_exception_store *store, 634db6bfe0SAlasdair G Kergon sector_t *numerator, sector_t *denominator) 644db6bfe0SAlasdair G Kergon { 654db6bfe0SAlasdair G Kergon *numerator = ((struct transient_c *) store->context)->next_free; 6649beb2b8SJonathan Brassow *denominator = get_dev_size(store->cow->bdev); 674db6bfe0SAlasdair G Kergon } 684db6bfe0SAlasdair G Kergon 69493df71cSJonathan Brassow static int transient_ctr(struct dm_exception_store *store, 70493df71cSJonathan Brassow unsigned argc, char **argv) 714db6bfe0SAlasdair G Kergon { 724db6bfe0SAlasdair G Kergon struct transient_c *tc; 734db6bfe0SAlasdair G Kergon 744db6bfe0SAlasdair G Kergon tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL); 754db6bfe0SAlasdair G Kergon if (!tc) 764db6bfe0SAlasdair G Kergon return -ENOMEM; 774db6bfe0SAlasdair G Kergon 784db6bfe0SAlasdair G Kergon tc->next_free = 0; 794db6bfe0SAlasdair G Kergon store->context = tc; 804db6bfe0SAlasdair G Kergon 814db6bfe0SAlasdair G Kergon return 0; 824db6bfe0SAlasdair G Kergon } 834db6bfe0SAlasdair G Kergon 84493df71cSJonathan Brassow static int transient_status(struct dm_exception_store *store, 85493df71cSJonathan Brassow status_type_t status, char *result, 86493df71cSJonathan Brassow unsigned maxlen) 87493df71cSJonathan Brassow { 88493df71cSJonathan Brassow int sz = 0; 89493df71cSJonathan Brassow 90493df71cSJonathan Brassow return sz; 91493df71cSJonathan Brassow } 92493df71cSJonathan Brassow 93493df71cSJonathan Brassow static struct dm_exception_store_type _transient_type = { 94493df71cSJonathan Brassow .name = "transient", 95493df71cSJonathan Brassow .module = THIS_MODULE, 96493df71cSJonathan Brassow .ctr = transient_ctr, 97493df71cSJonathan Brassow .dtr = transient_dtr, 98493df71cSJonathan Brassow .read_metadata = transient_read_metadata, 99493df71cSJonathan Brassow .prepare_exception = transient_prepare_exception, 100493df71cSJonathan Brassow .commit_exception = transient_commit_exception, 101493df71cSJonathan Brassow .fraction_full = transient_fraction_full, 102493df71cSJonathan Brassow .status = transient_status, 103493df71cSJonathan Brassow }; 104493df71cSJonathan Brassow 105493df71cSJonathan Brassow static struct dm_exception_store_type _transient_compat_type = { 106493df71cSJonathan Brassow .name = "N", 107493df71cSJonathan Brassow .module = THIS_MODULE, 108493df71cSJonathan Brassow .ctr = transient_ctr, 109493df71cSJonathan Brassow .dtr = transient_dtr, 110493df71cSJonathan Brassow .read_metadata = transient_read_metadata, 111493df71cSJonathan Brassow .prepare_exception = transient_prepare_exception, 112493df71cSJonathan Brassow .commit_exception = transient_commit_exception, 113493df71cSJonathan Brassow .fraction_full = transient_fraction_full, 114493df71cSJonathan Brassow .status = transient_status, 115493df71cSJonathan Brassow }; 116493df71cSJonathan Brassow 1174db6bfe0SAlasdair G Kergon int dm_transient_snapshot_init(void) 1184db6bfe0SAlasdair G Kergon { 119493df71cSJonathan Brassow int r; 120493df71cSJonathan Brassow 121493df71cSJonathan Brassow r = dm_exception_store_type_register(&_transient_type); 122493df71cSJonathan Brassow if (r) { 123493df71cSJonathan Brassow DMWARN("Unable to register transient exception store type"); 124493df71cSJonathan Brassow return r; 125493df71cSJonathan Brassow } 126493df71cSJonathan Brassow 127493df71cSJonathan Brassow r = dm_exception_store_type_register(&_transient_compat_type); 128493df71cSJonathan Brassow if (r) { 129493df71cSJonathan Brassow DMWARN("Unable to register old-style transient " 130493df71cSJonathan Brassow "exception store type"); 131493df71cSJonathan Brassow dm_exception_store_type_unregister(&_transient_type); 132493df71cSJonathan Brassow return r; 133493df71cSJonathan Brassow } 134493df71cSJonathan Brassow 135493df71cSJonathan Brassow return r; 1364db6bfe0SAlasdair G Kergon } 1374db6bfe0SAlasdair G Kergon 1384db6bfe0SAlasdair G Kergon void dm_transient_snapshot_exit(void) 1394db6bfe0SAlasdair G Kergon { 140493df71cSJonathan Brassow dm_exception_store_type_unregister(&_transient_type); 141493df71cSJonathan Brassow dm_exception_store_type_unregister(&_transient_compat_type); 1424db6bfe0SAlasdair G Kergon } 143