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 #include "dm-snap.h" 104db6bfe0SAlasdair G Kergon 114db6bfe0SAlasdair G Kergon #include <linux/mm.h> 124db6bfe0SAlasdair G Kergon #include <linux/pagemap.h> 134db6bfe0SAlasdair G Kergon #include <linux/vmalloc.h> 144db6bfe0SAlasdair G Kergon #include <linux/slab.h> 154db6bfe0SAlasdair G Kergon #include <linux/dm-io.h> 164db6bfe0SAlasdair G Kergon 174db6bfe0SAlasdair G Kergon #define DM_MSG_PREFIX "transient snapshot" 184db6bfe0SAlasdair G Kergon 194db6bfe0SAlasdair G Kergon /*----------------------------------------------------------------- 204db6bfe0SAlasdair G Kergon * Implementation of the store for non-persistent snapshots. 214db6bfe0SAlasdair G Kergon *---------------------------------------------------------------*/ 224db6bfe0SAlasdair G Kergon struct transient_c { 234db6bfe0SAlasdair G Kergon sector_t next_free; 244db6bfe0SAlasdair G Kergon }; 254db6bfe0SAlasdair G Kergon 264db6bfe0SAlasdair G Kergon static void transient_destroy(struct dm_exception_store *store) 274db6bfe0SAlasdair G Kergon { 284db6bfe0SAlasdair G Kergon kfree(store->context); 294db6bfe0SAlasdair G Kergon } 304db6bfe0SAlasdair G Kergon 31a159c1acSJonathan Brassow static int transient_read_metadata(struct dm_exception_store *store, 32a159c1acSJonathan Brassow int (*callback)(void *callback_context, 33a159c1acSJonathan Brassow chunk_t old, chunk_t new), 34a159c1acSJonathan Brassow void *callback_context) 354db6bfe0SAlasdair G Kergon { 364db6bfe0SAlasdair G Kergon return 0; 374db6bfe0SAlasdair G Kergon } 384db6bfe0SAlasdair G Kergon 39a159c1acSJonathan Brassow static int transient_prepare_exception(struct dm_exception_store *store, 404db6bfe0SAlasdair G Kergon struct dm_snap_exception *e) 414db6bfe0SAlasdair G Kergon { 42b2a11465SJonathan Brassow struct transient_c *tc = store->context; 434db6bfe0SAlasdair G Kergon sector_t size = get_dev_size(store->snap->cow->bdev); 444db6bfe0SAlasdair G Kergon 454db6bfe0SAlasdair G Kergon if (size < (tc->next_free + store->snap->chunk_size)) 464db6bfe0SAlasdair G Kergon return -1; 474db6bfe0SAlasdair G Kergon 484db6bfe0SAlasdair G Kergon e->new_chunk = sector_to_chunk(store->snap, tc->next_free); 494db6bfe0SAlasdair G Kergon tc->next_free += store->snap->chunk_size; 504db6bfe0SAlasdair G Kergon 514db6bfe0SAlasdair G Kergon return 0; 524db6bfe0SAlasdair G Kergon } 534db6bfe0SAlasdair G Kergon 54a159c1acSJonathan Brassow static void transient_commit_exception(struct dm_exception_store *store, 554db6bfe0SAlasdair G Kergon struct dm_snap_exception *e, 564db6bfe0SAlasdair G Kergon void (*callback) (void *, int success), 574db6bfe0SAlasdair G Kergon void *callback_context) 584db6bfe0SAlasdair G Kergon { 594db6bfe0SAlasdair G Kergon /* Just succeed */ 604db6bfe0SAlasdair G Kergon callback(callback_context, 1); 614db6bfe0SAlasdair G Kergon } 624db6bfe0SAlasdair G Kergon 634db6bfe0SAlasdair G Kergon static void transient_fraction_full(struct dm_exception_store *store, 644db6bfe0SAlasdair G Kergon sector_t *numerator, sector_t *denominator) 654db6bfe0SAlasdair G Kergon { 664db6bfe0SAlasdair G Kergon *numerator = ((struct transient_c *) store->context)->next_free; 674db6bfe0SAlasdair G Kergon *denominator = get_dev_size(store->snap->cow->bdev); 684db6bfe0SAlasdair G Kergon } 694db6bfe0SAlasdair G Kergon 704db6bfe0SAlasdair G Kergon int dm_create_transient(struct dm_exception_store *store) 714db6bfe0SAlasdair G Kergon { 724db6bfe0SAlasdair G Kergon struct transient_c *tc; 734db6bfe0SAlasdair G Kergon 74b2a11465SJonathan Brassow store->type.dtr = transient_destroy; 75b2a11465SJonathan Brassow store->type.read_metadata = transient_read_metadata; 76b2a11465SJonathan Brassow store->type.prepare_exception = transient_prepare_exception; 77b2a11465SJonathan Brassow store->type.commit_exception = transient_commit_exception; 78b2a11465SJonathan Brassow store->type.drop_snapshot = NULL; 79b2a11465SJonathan Brassow store->type.fraction_full = transient_fraction_full; 804db6bfe0SAlasdair G Kergon 814db6bfe0SAlasdair G Kergon tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL); 824db6bfe0SAlasdair G Kergon if (!tc) 834db6bfe0SAlasdair G Kergon return -ENOMEM; 844db6bfe0SAlasdair G Kergon 854db6bfe0SAlasdair G Kergon tc->next_free = 0; 864db6bfe0SAlasdair G Kergon store->context = tc; 874db6bfe0SAlasdair G Kergon 884db6bfe0SAlasdair G Kergon return 0; 894db6bfe0SAlasdair G Kergon } 904db6bfe0SAlasdair G Kergon 914db6bfe0SAlasdair G Kergon int dm_transient_snapshot_init(void) 924db6bfe0SAlasdair G Kergon { 934db6bfe0SAlasdair G Kergon return 0; 944db6bfe0SAlasdair G Kergon } 954db6bfe0SAlasdair G Kergon 964db6bfe0SAlasdair G Kergon void dm_transient_snapshot_exit(void) 974db6bfe0SAlasdair G Kergon { 984db6bfe0SAlasdair G Kergon } 99