dm-space-map-disk.c revision 7c3d3f2a87b01ff167a5f048285d5e3dee920235
1/* 2 * Copyright (C) 2011 Red Hat, Inc. 3 * 4 * This file is released under the GPL. 5 */ 6 7#include "dm-space-map-common.h" 8#include "dm-space-map-disk.h" 9#include "dm-space-map.h" 10#include "dm-transaction-manager.h" 11 12#include <linux/list.h> 13#include <linux/slab.h> 14#include <linux/export.h> 15#include <linux/device-mapper.h> 16 17#define DM_MSG_PREFIX "space map disk" 18 19/*----------------------------------------------------------------*/ 20 21/* 22 * Space map interface. 23 */ 24struct sm_disk { 25 struct dm_space_map sm; 26 27 struct ll_disk ll; 28 struct ll_disk old_ll; 29 30 dm_block_t begin; 31 dm_block_t nr_allocated_this_transaction; 32}; 33 34static void sm_disk_destroy(struct dm_space_map *sm) 35{ 36 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 37 38 kfree(smd); 39} 40 41static int sm_disk_extend(struct dm_space_map *sm, dm_block_t extra_blocks) 42{ 43 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 44 45 return sm_ll_extend(&smd->ll, extra_blocks); 46} 47 48static int sm_disk_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count) 49{ 50 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 51 *count = smd->old_ll.nr_blocks; 52 53 return 0; 54} 55 56static int sm_disk_get_nr_free(struct dm_space_map *sm, dm_block_t *count) 57{ 58 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 59 *count = (smd->old_ll.nr_blocks - smd->old_ll.nr_allocated) - smd->nr_allocated_this_transaction; 60 61 return 0; 62} 63 64static int sm_disk_get_count(struct dm_space_map *sm, dm_block_t b, 65 uint32_t *result) 66{ 67 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 68 return sm_ll_lookup(&smd->ll, b, result); 69} 70 71static int sm_disk_count_is_more_than_one(struct dm_space_map *sm, dm_block_t b, 72 int *result) 73{ 74 int r; 75 uint32_t count; 76 77 r = sm_disk_get_count(sm, b, &count); 78 if (r) 79 return r; 80 81 return count > 1; 82} 83 84static int sm_disk_set_count(struct dm_space_map *sm, dm_block_t b, 85 uint32_t count) 86{ 87 int r; 88 uint32_t old_count; 89 enum allocation_event ev; 90 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 91 92 r = sm_ll_insert(&smd->ll, b, count, &ev); 93 if (!r) { 94 switch (ev) { 95 case SM_NONE: 96 break; 97 98 case SM_ALLOC: 99 /* 100 * This _must_ be free in the prior transaction 101 * otherwise we've lost atomicity. 102 */ 103 smd->nr_allocated_this_transaction++; 104 break; 105 106 case SM_FREE: 107 /* 108 * It's only free if it's also free in the last 109 * transaction. 110 */ 111 r = sm_ll_lookup(&smd->old_ll, b, &old_count); 112 if (r) 113 return r; 114 115 if (!old_count) 116 smd->nr_allocated_this_transaction--; 117 break; 118 } 119 } 120 121 return r; 122} 123 124static int sm_disk_inc_block(struct dm_space_map *sm, dm_block_t b) 125{ 126 int r; 127 enum allocation_event ev; 128 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 129 130 r = sm_ll_inc(&smd->ll, b, &ev); 131 if (!r && (ev == SM_ALLOC)) 132 /* 133 * This _must_ be free in the prior transaction 134 * otherwise we've lost atomicity. 135 */ 136 smd->nr_allocated_this_transaction++; 137 138 return r; 139} 140 141static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b) 142{ 143 int r; 144 uint32_t old_count; 145 enum allocation_event ev; 146 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 147 148 r = sm_ll_dec(&smd->ll, b, &ev); 149 if (!r && (ev == SM_FREE)) { 150 /* 151 * It's only free if it's also free in the last 152 * transaction. 153 */ 154 r = sm_ll_lookup(&smd->old_ll, b, &old_count); 155 if (r) 156 return r; 157 158 if (!old_count) 159 smd->nr_allocated_this_transaction--; 160 } 161 162 return r; 163} 164 165static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b) 166{ 167 int r; 168 enum allocation_event ev; 169 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 170 171 /* FIXME: we should loop round a couple of times */ 172 r = sm_ll_find_free_block(&smd->old_ll, smd->begin, smd->old_ll.nr_blocks, b); 173 if (r) 174 return r; 175 176 smd->begin = *b + 1; 177 r = sm_ll_inc(&smd->ll, *b, &ev); 178 if (!r) { 179 BUG_ON(ev != SM_ALLOC); 180 smd->nr_allocated_this_transaction++; 181 } 182 183 return r; 184} 185 186static int sm_disk_commit(struct dm_space_map *sm) 187{ 188 int r; 189 dm_block_t nr_free; 190 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 191 192 r = sm_disk_get_nr_free(sm, &nr_free); 193 if (r) 194 return r; 195 196 r = sm_ll_commit(&smd->ll); 197 if (r) 198 return r; 199 200 memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll)); 201 smd->begin = 0; 202 smd->nr_allocated_this_transaction = 0; 203 204 r = sm_disk_get_nr_free(sm, &nr_free); 205 if (r) 206 return r; 207 208 return 0; 209} 210 211static int sm_disk_root_size(struct dm_space_map *sm, size_t *result) 212{ 213 *result = sizeof(struct disk_sm_root); 214 215 return 0; 216} 217 218static int sm_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max) 219{ 220 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 221 struct disk_sm_root root_le; 222 223 root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks); 224 root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated); 225 root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root); 226 root_le.ref_count_root = cpu_to_le64(smd->ll.ref_count_root); 227 228 if (max < sizeof(root_le)) 229 return -ENOSPC; 230 231 memcpy(where_le, &root_le, sizeof(root_le)); 232 233 return 0; 234} 235 236/*----------------------------------------------------------------*/ 237 238static struct dm_space_map ops = { 239 .destroy = sm_disk_destroy, 240 .extend = sm_disk_extend, 241 .get_nr_blocks = sm_disk_get_nr_blocks, 242 .get_nr_free = sm_disk_get_nr_free, 243 .get_count = sm_disk_get_count, 244 .count_is_more_than_one = sm_disk_count_is_more_than_one, 245 .set_count = sm_disk_set_count, 246 .inc_block = sm_disk_inc_block, 247 .dec_block = sm_disk_dec_block, 248 .new_block = sm_disk_new_block, 249 .commit = sm_disk_commit, 250 .root_size = sm_disk_root_size, 251 .copy_root = sm_disk_copy_root, 252 .register_threshold_callback = NULL 253}; 254 255struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm, 256 dm_block_t nr_blocks) 257{ 258 int r; 259 struct sm_disk *smd; 260 261 smd = kmalloc(sizeof(*smd), GFP_KERNEL); 262 if (!smd) 263 return ERR_PTR(-ENOMEM); 264 265 smd->begin = 0; 266 smd->nr_allocated_this_transaction = 0; 267 memcpy(&smd->sm, &ops, sizeof(smd->sm)); 268 269 r = sm_ll_new_disk(&smd->ll, tm); 270 if (r) 271 goto bad; 272 273 r = sm_ll_extend(&smd->ll, nr_blocks); 274 if (r) 275 goto bad; 276 277 r = sm_disk_commit(&smd->sm); 278 if (r) 279 goto bad; 280 281 return &smd->sm; 282 283bad: 284 kfree(smd); 285 return ERR_PTR(r); 286} 287EXPORT_SYMBOL_GPL(dm_sm_disk_create); 288 289struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm, 290 void *root_le, size_t len) 291{ 292 int r; 293 struct sm_disk *smd; 294 295 smd = kmalloc(sizeof(*smd), GFP_KERNEL); 296 if (!smd) 297 return ERR_PTR(-ENOMEM); 298 299 smd->begin = 0; 300 smd->nr_allocated_this_transaction = 0; 301 memcpy(&smd->sm, &ops, sizeof(smd->sm)); 302 303 r = sm_ll_open_disk(&smd->ll, tm, root_le, len); 304 if (r) 305 goto bad; 306 307 r = sm_disk_commit(&smd->sm); 308 if (r) 309 goto bad; 310 311 return &smd->sm; 312 313bad: 314 kfree(smd); 315 return ERR_PTR(r); 316} 317EXPORT_SYMBOL_GPL(dm_sm_disk_open); 318 319/*----------------------------------------------------------------*/ 320