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 */ 24 struct 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 34 static 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 41 static 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 48 static 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 56 static 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 64 static 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 71 static 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 84 static 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 } 123 124 static 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 } 140 141 static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b) 142 { 143 enum allocation_event ev; 144 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 145 146 return sm_ll_dec(&smd->ll, b, &ev); 147 } 148 149 static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b) 150 { 151 int r; 152 enum allocation_event ev; 153 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 154 155 /* FIXME: we should loop round a couple of times */ 156 r = sm_ll_find_free_block(&smd->old_ll, smd->begin, smd->old_ll.nr_blocks, b); 157 if (r) 158 return r; 159 160 smd->begin = *b + 1; 161 r = sm_ll_inc(&smd->ll, *b, &ev); 162 if (!r) { 163 BUG_ON(ev != SM_ALLOC); 164 smd->nr_allocated_this_transaction++; 165 } 166 167 return r; 168 } 169 170 static int sm_disk_commit(struct dm_space_map *sm) 171 { 172 int r; 173 dm_block_t nr_free; 174 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 175 176 r = sm_disk_get_nr_free(sm, &nr_free); 177 if (r) 178 return r; 179 180 r = sm_ll_commit(&smd->ll); 181 if (r) 182 return r; 183 184 memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll)); 185 smd->begin = 0; 186 smd->nr_allocated_this_transaction = 0; 187 188 r = sm_disk_get_nr_free(sm, &nr_free); 189 if (r) 190 return r; 191 192 return 0; 193 } 194 195 static int sm_disk_root_size(struct dm_space_map *sm, size_t *result) 196 { 197 *result = sizeof(struct disk_sm_root); 198 199 return 0; 200 } 201 202 static int sm_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max) 203 { 204 struct sm_disk *smd = container_of(sm, struct sm_disk, sm); 205 struct disk_sm_root root_le; 206 207 root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks); 208 root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated); 209 root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root); 210 root_le.ref_count_root = cpu_to_le64(smd->ll.ref_count_root); 211 212 if (max < sizeof(root_le)) 213 return -ENOSPC; 214 215 memcpy(where_le, &root_le, sizeof(root_le)); 216 217 return 0; 218 } 219 220 /*----------------------------------------------------------------*/ 221 222 static struct dm_space_map ops = { 223 .destroy = sm_disk_destroy, 224 .extend = sm_disk_extend, 225 .get_nr_blocks = sm_disk_get_nr_blocks, 226 .get_nr_free = sm_disk_get_nr_free, 227 .get_count = sm_disk_get_count, 228 .count_is_more_than_one = sm_disk_count_is_more_than_one, 229 .set_count = sm_disk_set_count, 230 .inc_block = sm_disk_inc_block, 231 .dec_block = sm_disk_dec_block, 232 .new_block = sm_disk_new_block, 233 .commit = sm_disk_commit, 234 .root_size = sm_disk_root_size, 235 .copy_root = sm_disk_copy_root, 236 .register_threshold_callback = NULL 237 }; 238 239 struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm, 240 dm_block_t nr_blocks) 241 { 242 int r; 243 struct sm_disk *smd; 244 245 smd = kmalloc(sizeof(*smd), GFP_KERNEL); 246 if (!smd) 247 return ERR_PTR(-ENOMEM); 248 249 smd->begin = 0; 250 smd->nr_allocated_this_transaction = 0; 251 memcpy(&smd->sm, &ops, sizeof(smd->sm)); 252 253 r = sm_ll_new_disk(&smd->ll, tm); 254 if (r) 255 goto bad; 256 257 r = sm_ll_extend(&smd->ll, nr_blocks); 258 if (r) 259 goto bad; 260 261 r = sm_disk_commit(&smd->sm); 262 if (r) 263 goto bad; 264 265 return &smd->sm; 266 267 bad: 268 kfree(smd); 269 return ERR_PTR(r); 270 } 271 EXPORT_SYMBOL_GPL(dm_sm_disk_create); 272 273 struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm, 274 void *root_le, size_t len) 275 { 276 int r; 277 struct sm_disk *smd; 278 279 smd = kmalloc(sizeof(*smd), GFP_KERNEL); 280 if (!smd) 281 return ERR_PTR(-ENOMEM); 282 283 smd->begin = 0; 284 smd->nr_allocated_this_transaction = 0; 285 memcpy(&smd->sm, &ops, sizeof(smd->sm)); 286 287 r = sm_ll_open_disk(&smd->ll, tm, root_le, len); 288 if (r) 289 goto bad; 290 291 r = sm_disk_commit(&smd->sm); 292 if (r) 293 goto bad; 294 295 return &smd->sm; 296 297 bad: 298 kfree(smd); 299 return ERR_PTR(r); 300 } 301 EXPORT_SYMBOL_GPL(dm_sm_disk_open); 302 303 /*----------------------------------------------------------------*/ 304