block/qcow2-bitmap.c

   1 /*
   2  * Bitmaps for the QCOW version 2 format
   3  *
   4  * Copyright (c) 2014-2017 Vladimir Sementsov-Ogievskiy
   5  *
   6  * This file is derived from qcow2-snapshot.c, original copyright:
   7  * Copyright (c) 2004-2006 Fabrice Bellard
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a copy
  10  * of this software and associated documentation files (the "Software"), to deal
  11  * in the Software without restriction, including without limitation the rights
  12  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  13  * copies of the Software, and to permit persons to whom the Software is
  14  * furnished to do so, subject to the following conditions:
  15  *
  16  * The above copyright notice and this permission notice shall be included in
  17  * all copies or substantial portions of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  22  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  23  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  24  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  25  * THE SOFTWARE.
  26  */
  27
  28 #include "qemu/osdep.h"
  29 #include "qapi/error.h"
  30 #include "qemu/cutils.h"
  31
  32 #include "block/block_int.h"
  33 #include "block/qcow2.h"
  34
  35 /* NOTICE: BME here means Bitmaps Extension and used as a namespace for
  36  * _internal_ constants. Please do not use this _internal_ abbreviation for
  37  * other needs and/or outside of this file. */
  38
  39 /* Bitmap directory entry constraints */
  40 #define BME_MAX_TABLE_SIZE 0x8000000
  41 #define BME_MAX_PHYS_SIZE 0x20000000 /* restrict BdrvDirtyBitmap size in RAM */
  42 #define BME_MAX_GRANULARITY_BITS 31
  43 #define BME_MIN_GRANULARITY_BITS 9
  44 #define BME_MAX_NAME_SIZE 1023
  45
  46 #if BME_MAX_TABLE_SIZE * 8ULL > INT_MAX
  47 #error In the code bitmap table physical size assumed to fit into int
  48 #endif
  49
  50 /* Bitmap directory entry flags */
  51 #define BME_RESERVED_FLAGS 0xfffffffcU
  52 #define BME_FLAG_IN_USE (1U << 0)
  53 #define BME_FLAG_AUTO   (1U << 1)
  54
  55 /* bits [1, 8] U [56, 63] are reserved */
  56 #define BME_TABLE_ENTRY_RESERVED_MASK 0xff000000000001feULL
  57 #define BME_TABLE_ENTRY_OFFSET_MASK 0x00fffffffffffe00ULL
  58 #define BME_TABLE_ENTRY_FLAG_ALL_ONES (1ULL << 0)
  59
  60 typedef struct QEMU_PACKED Qcow2BitmapDirEntry {
  61     /* header is 8 byte aligned */
  62     uint64_t bitmap_table_offset;
  63
  64     uint32_t bitmap_table_size;
  65     uint32_t flags;
  66
  67     uint8_t type;
  68     uint8_t granularity_bits;
  69     uint16_t name_size;
  70     uint32_t extra_data_size;
  71     /* extra data follows  */
  72     /* name follows  */
  73 } Qcow2BitmapDirEntry;
  74
  75 typedef struct Qcow2BitmapTable {
  76     uint64_t offset;
  77     uint32_t size; /* number of 64bit entries */
  78     QSIMPLEQ_ENTRY(Qcow2BitmapTable) entry;
  79 } Qcow2BitmapTable;
  80 typedef QSIMPLEQ_HEAD(Qcow2BitmapTableList, Qcow2BitmapTable)
  81     Qcow2BitmapTableList;
  82
  83 typedef struct Qcow2Bitmap {
  84     Qcow2BitmapTable table;
  85     uint32_t flags;
  86     uint8_t granularity_bits;
  87     char *name;
  88
  89     BdrvDirtyBitmap *dirty_bitmap;
  90
  91     QSIMPLEQ_ENTRY(Qcow2Bitmap) entry;
  92 } Qcow2Bitmap;
  93 typedef QSIMPLEQ_HEAD(Qcow2BitmapList, Qcow2Bitmap) Qcow2BitmapList;
  94
  95 typedef enum BitmapType {
  96     BT_DIRTY_TRACKING_BITMAP = 1
  97 } BitmapType;
  98
  99 static inline bool can_write(BlockDriverState *bs)
 100 {
 101     return !bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE);
 102 }
 103
 104 static int update_header_sync(BlockDriverState *bs)
 105 {
 106     int ret;
 107
 108     ret = qcow2_update_header(bs);
 109     if (ret < 0) {
 110         return ret;
 111     }
 112
 113     return bdrv_flush(bs);
 114 }
 115
 116 static inline void bitmap_table_to_be(uint64_t *bitmap_table, size_t size)
 117 {
 118     size_t i;
 119
 120     for (i = 0; i < size; ++i) {
 121         cpu_to_be64s(&bitmap_table[i]);
 122     }
 123 }
 124
 125 static int check_table_entry(uint64_t entry, int cluster_size)
 126 {
 127     uint64_t offset;
 128
 129     if (entry & BME_TABLE_ENTRY_RESERVED_MASK) {
 130         return -EINVAL;
 131     }
 132
 133     offset = entry & BME_TABLE_ENTRY_OFFSET_MASK;
 134     if (offset != 0) {
 135         /* if offset specified, bit 0 is reserved */
 136         if (entry & BME_TABLE_ENTRY_FLAG_ALL_ONES) {
 137             return -EINVAL;
 138         }
 139
 140         if (offset % cluster_size != 0) {
 141             return -EINVAL;
 142         }
 143     }
 144
 145     return 0;
 146 }
 147
 148 static int check_constraints_on_bitmap(BlockDriverState *bs,
 149                                        const char *name,
 150                                        uint32_t granularity,
 151                                        Error **errp)
 152 {
 153     BDRVQcow2State *s = bs->opaque;
 154     int granularity_bits = ctz32(granularity);
 155     int64_t len = bdrv_getlength(bs);
 156
 157     assert(granularity > 0);
 158     assert((granularity & (granularity - 1)) == 0);
 159
 160     if (len < 0) {
 161         error_setg_errno(errp, -len, "Failed to get size of '%s'",
 162                          bdrv_get_device_or_node_name(bs));
 163         return len;
 164     }
 165
 166     if (granularity_bits > BME_MAX_GRANULARITY_BITS) {
 167         error_setg(errp, "Granularity exceeds maximum (%llu bytes)",
 168                    1ULL << BME_MAX_GRANULARITY_BITS);
 169         return -EINVAL;
 170     }
 171     if (granularity_bits < BME_MIN_GRANULARITY_BITS) {
 172         error_setg(errp, "Granularity is under minimum (%llu bytes)",
 173                    1ULL << BME_MIN_GRANULARITY_BITS);
 174         return -EINVAL;
 175     }
 176
 177     if ((len > (uint64_t)BME_MAX_PHYS_SIZE << granularity_bits) ||
 178         (len > (uint64_t)BME_MAX_TABLE_SIZE * s->cluster_size <<
 179                granularity_bits))
 180     {
 181         error_setg(errp, "Too much space will be occupied by the bitmap. "
 182                    "Use larger granularity");
 183         return -EINVAL;
 184     }
 185
 186     if (strlen(name) > BME_MAX_NAME_SIZE) {
 187         error_setg(errp, "Name length exceeds maximum (%u characters)",
 188                    BME_MAX_NAME_SIZE);
 189         return -EINVAL;
 190     }
 191
 192     return 0;
 193 }
 194
 195 static void clear_bitmap_table(BlockDriverState *bs, uint64_t *bitmap_table,
 196                                uint32_t bitmap_table_size)
 197 {
 198     BDRVQcow2State *s = bs->opaque;
 199     int i;
 200
 201     for (i = 0; i < bitmap_table_size; ++i) {
 202         uint64_t addr = bitmap_table[i] & BME_TABLE_ENTRY_OFFSET_MASK;
 203         if (!addr) {
 204             continue;
 205         }
 206
 207         qcow2_free_clusters(bs, addr, s->cluster_size, QCOW2_DISCARD_OTHER);
 208         bitmap_table[i] = 0;
 209     }
 210 }
 211
 212 static int bitmap_table_load(BlockDriverState *bs, Qcow2BitmapTable *tb,
 213                              uint64_t **bitmap_table)
 214 {
 215     int ret;
 216     BDRVQcow2State *s = bs->opaque;
 217     uint32_t i;
 218     uint64_t *table;
 219
 220     assert(tb->size != 0);
 221     table = g_try_new(uint64_t, tb->size);
 222     if (table == NULL) {
 223         return -ENOMEM;
 224     }
 225
 226     assert(tb->size <= BME_MAX_TABLE_SIZE);
 227     ret = bdrv_pread(bs->file, tb->offset,
 228                      table, tb->size * sizeof(uint64_t));
 229     if (ret < 0) {
 230         goto fail;
 231     }
 232
 233     for (i = 0; i < tb->size; ++i) {
 234         be64_to_cpus(&table[i]);
 235         ret = check_table_entry(table[i], s->cluster_size);
 236         if (ret < 0) {
 237             goto fail;
 238         }
 239     }
 240
 241     *bitmap_table = table;
 242     return 0;
 243
 244 fail:
 245     g_free(table);
 246
 247     return ret;
 248 }
 249
 250 static int free_bitmap_clusters(BlockDriverState *bs, Qcow2BitmapTable *tb)
 251 {
 252     int ret;
 253     uint64_t *bitmap_table;
 254
 255     ret = bitmap_table_load(bs, tb, &bitmap_table);
 256     if (ret < 0) {
 257         assert(bitmap_table == NULL);
 258         return ret;
 259     }
 260
 261     clear_bitmap_table(bs, bitmap_table, tb->size);
 262     qcow2_free_clusters(bs, tb->offset, tb->size * sizeof(uint64_t),
 263                         QCOW2_DISCARD_OTHER);
 264     g_free(bitmap_table);
 265
 266     tb->offset = 0;
 267     tb->size = 0;
 268
 269     return 0;
 270 }
 271
 272 /* This function returns the number of disk sectors covered by a single qcow2
 273  * cluster of bitmap data. */
 274 static uint64_t sectors_covered_by_bitmap_cluster(const BDRVQcow2State *s,
 275                                                   const BdrvDirtyBitmap *bitmap)
 276 {
 277     uint32_t sector_granularity =
 278             bdrv_dirty_bitmap_granularity(bitmap) >> BDRV_SECTOR_BITS;
 279
 280     return (uint64_t)sector_granularity * (s->cluster_size << 3);
 281 }
 282
 283 /* load_bitmap_data
 284  * @bitmap_table entries must satisfy specification constraints.
 285  * @bitmap must be cleared */
 286 static int load_bitmap_data(BlockDriverState *bs,
 287                             const uint64_t *bitmap_table,
 288                             uint32_t bitmap_table_size,
 289                             BdrvDirtyBitmap *bitmap)
 290 {
 291     int ret = 0;
 292     BDRVQcow2State *s = bs->opaque;
 293     uint64_t sector, sbc;
 294     uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
 295     uint8_t *buf = NULL;
 296     uint64_t i, tab_size =
 297             size_to_clusters(s,
 298                 bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size));
 299
 300     if (tab_size != bitmap_table_size || tab_size > BME_MAX_TABLE_SIZE) {
 301         return -EINVAL;
 302     }
 303
 304     buf = g_malloc(s->cluster_size);
 305     sbc = sectors_covered_by_bitmap_cluster(s, bitmap);
 306     for (i = 0, sector = 0; i < tab_size; ++i, sector += sbc) {
 307         uint64_t count = MIN(bm_size - sector, sbc);
 308         uint64_t entry = bitmap_table[i];
 309         uint64_t offset = entry & BME_TABLE_ENTRY_OFFSET_MASK;
 310
 311         assert(check_table_entry(entry, s->cluster_size) == 0);
 312
 313         if (offset == 0) {
 314             if (entry & BME_TABLE_ENTRY_FLAG_ALL_ONES) {
 315                 bdrv_dirty_bitmap_deserialize_ones(bitmap, sector, count,
 316                                                    false);
 317             } else {
 318                 /* No need to deserialize zeros because the dirty bitmap is
 319                  * already cleared */
 320             }
 321         } else {
 322             ret = bdrv_pread(bs->file, offset, buf, s->cluster_size);
 323             if (ret < 0) {
 324                 goto finish;
 325             }
 326             bdrv_dirty_bitmap_deserialize_part(bitmap, buf, sector, count,
 327                                                false);
 328         }
 329     }
 330     ret = 0;
 331
 332     bdrv_dirty_bitmap_deserialize_finish(bitmap);
 333
 334 finish:
 335     g_free(buf);
 336
 337     return ret;
 338 }
 339
 340 static BdrvDirtyBitmap *load_bitmap(BlockDriverState *bs,
 341                                     Qcow2Bitmap *bm, Error **errp)
 342 {
 343     int ret;
 344     uint64_t *bitmap_table = NULL;
 345     uint32_t granularity;
 346     BdrvDirtyBitmap *bitmap = NULL;
 347
 348     if (bm->flags & BME_FLAG_IN_USE) {
 349         error_setg(errp, "Bitmap '%s' is in use", bm->name);
 350         goto fail;
 351     }
 352
 353     ret = bitmap_table_load(bs, &bm->table, &bitmap_table);
 354     if (ret < 0) {
 355         error_setg_errno(errp, -ret,
 356                          "Could not read bitmap_table table from image for "
 357                          "bitmap '%s'", bm->name);
 358         goto fail;
 359     }
 360
 361     granularity = 1U << bm->granularity_bits;
 362     bitmap = bdrv_create_dirty_bitmap(bs, granularity, bm->name, errp);
 363     if (bitmap == NULL) {
 364         goto fail;
 365     }
 366
 367     ret = load_bitmap_data(bs, bitmap_table, bm->table.size, bitmap);
 368     if (ret < 0) {
 369         error_setg_errno(errp, -ret, "Could not read bitmap '%s' from image",
 370                          bm->name);
 371         goto fail;
 372     }
 373
 374     g_free(bitmap_table);
 375     return bitmap;
 376
 377 fail:
 378     g_free(bitmap_table);
 379     if (bitmap != NULL) {
 380         bdrv_release_dirty_bitmap(bs, bitmap);
 381     }
 382
 383     return NULL;
 384 }
 385
 386 /*
 387  * Bitmap List
 388  */
 389
 390 /*
 391  * Bitmap List private functions
 392  * Only Bitmap List knows about bitmap directory structure in Qcow2.
 393  */
 394
 395 static inline void bitmap_dir_entry_to_cpu(Qcow2BitmapDirEntry *entry)
 396 {
 397     be64_to_cpus(&entry->bitmap_table_offset);
 398     be32_to_cpus(&entry->bitmap_table_size);
 399     be32_to_cpus(&entry->flags);
 400     be16_to_cpus(&entry->name_size);
 401     be32_to_cpus(&entry->extra_data_size);
 402 }
 403
 404 static inline void bitmap_dir_entry_to_be(Qcow2BitmapDirEntry *entry)
 405 {
 406     cpu_to_be64s(&entry->bitmap_table_offset);
 407     cpu_to_be32s(&entry->bitmap_table_size);
 408     cpu_to_be32s(&entry->flags);
 409     cpu_to_be16s(&entry->name_size);
 410     cpu_to_be32s(&entry->extra_data_size);
 411 }
 412
 413 static inline int calc_dir_entry_size(size_t name_size, size_t extra_data_size)
 414 {
 415     return align_offset(sizeof(Qcow2BitmapDirEntry) +
 416                         name_size + extra_data_size, 8);
 417 }
 418
 419 static inline int dir_entry_size(Qcow2BitmapDirEntry *entry)
 420 {
 421     return calc_dir_entry_size(entry->name_size, entry->extra_data_size);
 422 }
 423
 424 static inline const char *dir_entry_name_field(Qcow2BitmapDirEntry *entry)
 425 {
 426     return (const char *)(entry + 1) + entry->extra_data_size;
 427 }
 428
 429 static inline char *dir_entry_copy_name(Qcow2BitmapDirEntry *entry)
 430 {
 431     const char *name_field = dir_entry_name_field(entry);
 432     return g_strndup(name_field, entry->name_size);
 433 }
 434
 435 static inline Qcow2BitmapDirEntry *next_dir_entry(Qcow2BitmapDirEntry *entry)
 436 {
 437     return (Qcow2BitmapDirEntry *)((uint8_t *)entry + dir_entry_size(entry));
 438 }
 439
 440 static int check_dir_entry(BlockDriverState *bs, Qcow2BitmapDirEntry *entry)
 441 {
 442     BDRVQcow2State *s = bs->opaque;
 443     uint64_t phys_bitmap_bytes;
 444     int64_t len;
 445
 446     bool fail = (entry->bitmap_table_size == 0) ||
 447                 (entry->bitmap_table_offset == 0) ||
 448                 (entry->bitmap_table_offset % s->cluster_size) ||
 449                 (entry->bitmap_table_size > BME_MAX_TABLE_SIZE) ||
 450                 (entry->granularity_bits > BME_MAX_GRANULARITY_BITS) ||
 451                 (entry->granularity_bits < BME_MIN_GRANULARITY_BITS) ||
 452                 (entry->flags & BME_RESERVED_FLAGS) ||
 453                 (entry->name_size > BME_MAX_NAME_SIZE) ||
 454                 (entry->type != BT_DIRTY_TRACKING_BITMAP);
 455
 456     if (fail) {
 457         return -EINVAL;
 458     }
 459
 460     phys_bitmap_bytes = (uint64_t)entry->bitmap_table_size * s->cluster_size;
 461     len = bdrv_getlength(bs);
 462
 463     if (len < 0) {
 464         return len;
 465     }
 466
 467     fail = (phys_bitmap_bytes > BME_MAX_PHYS_SIZE) ||
 468            (len > ((phys_bitmap_bytes * 8) << entry->granularity_bits));
 469
 470     return fail ? -EINVAL : 0;
 471 }
 472
 473 static inline void bitmap_directory_to_be(uint8_t *dir, size_t size)
 474 {
 475     uint8_t *end = dir + size;
 476     while (dir < end) {
 477         Qcow2BitmapDirEntry *e = (Qcow2BitmapDirEntry *)dir;
 478         dir += dir_entry_size(e);
 479
 480         bitmap_dir_entry_to_be(e);
 481     }
 482 }
 483
 484 /*
 485  * Bitmap List public functions
 486  */
 487
 488 static void bitmap_free(Qcow2Bitmap *bm)
 489 {
 490     if (bm == NULL) {
 491         return;
 492     }
 493
 494     g_free(bm->name);
 495     g_free(bm);
 496 }
 497
 498 static void bitmap_list_free(Qcow2BitmapList *bm_list)
 499 {
 500     Qcow2Bitmap *bm;
 501
 502     if (bm_list == NULL) {
 503         return;
 504     }
 505
 506     while ((bm = QSIMPLEQ_FIRST(bm_list)) != NULL) {
 507         QSIMPLEQ_REMOVE_HEAD(bm_list, entry);
 508         bitmap_free(bm);
 509     }
 510
 511     g_free(bm_list);
 512 }
 513
 514 static Qcow2BitmapList *bitmap_list_new(void)
 515 {
 516     Qcow2BitmapList *bm_list = g_new(Qcow2BitmapList, 1);
 517     QSIMPLEQ_INIT(bm_list);
 518
 519     return bm_list;
 520 }
 521
 522 static uint32_t bitmap_list_count(Qcow2BitmapList *bm_list)
 523 {
 524     Qcow2Bitmap *bm;
 525     uint32_t nb_bitmaps = 0;
 526
 527     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
 528         nb_bitmaps++;
 529     }
 530
 531     return nb_bitmaps;
 532 }
 533
 534 /* bitmap_list_load
 535  * Get bitmap list from qcow2 image. Actually reads bitmap directory,
 536  * checks it and convert to bitmap list.
 537  */
 538 static Qcow2BitmapList *bitmap_list_load(BlockDriverState *bs, uint64_t offset,
 539                                          uint64_t size, Error **errp)
 540 {
 541     int ret;
 542     BDRVQcow2State *s = bs->opaque;
 543     uint8_t *dir, *dir_end;
 544     Qcow2BitmapDirEntry *e;
 545     uint32_t nb_dir_entries = 0;
 546     Qcow2BitmapList *bm_list = NULL;
 547
 548     if (size == 0) {
 549         error_setg(errp, "Requested bitmap directory size is zero");
 550         return NULL;
 551     }
 552
 553     if (size > QCOW2_MAX_BITMAP_DIRECTORY_SIZE) {
 554         error_setg(errp, "Requested bitmap directory size is too big");
 555         return NULL;
 556     }
 557
 558     dir = g_try_malloc(size);
 559     if (dir == NULL) {
 560         error_setg(errp, "Failed to allocate space for bitmap directory");
 561         return NULL;
 562     }
 563     dir_end = dir + size;
 564
 565     ret = bdrv_pread(bs->file, offset, dir, size);
 566     if (ret < 0) {
 567         error_setg_errno(errp, -ret, "Failed to read bitmap directory");
 568         goto fail;
 569     }
 570
 571     bm_list = bitmap_list_new();
 572     for (e = (Qcow2BitmapDirEntry *)dir;
 573          e < (Qcow2BitmapDirEntry *)dir_end;
 574          e = next_dir_entry(e))
 575     {
 576         Qcow2Bitmap *bm;
 577
 578         if ((uint8_t *)(e + 1) > dir_end) {
 579             goto broken_dir;
 580         }
 581
 582         if (++nb_dir_entries > s->nb_bitmaps) {
 583             error_setg(errp, "More bitmaps found than specified in header"
 584                        " extension");
 585             goto fail;
 586         }
 587         bitmap_dir_entry_to_cpu(e);
 588
 589         if ((uint8_t *)next_dir_entry(e) > dir_end) {
 590             goto broken_dir;
 591         }
 592
 593         if (e->extra_data_size != 0) {
 594             error_setg(errp, "Bitmap extra data is not supported");
 595             goto fail;
 596         }
 597
 598         ret = check_dir_entry(bs, e);
 599         if (ret < 0) {
 600             error_setg(errp, "Bitmap '%.*s' doesn't satisfy the constraints",
 601                        e->name_size, dir_entry_name_field(e));
 602             goto fail;
 603         }
 604
 605         bm = g_new0(Qcow2Bitmap, 1);
 606         bm->table.offset = e->bitmap_table_offset;
 607         bm->table.size = e->bitmap_table_size;
 608         bm->flags = e->flags;
 609         bm->granularity_bits = e->granularity_bits;
 610         bm->name = dir_entry_copy_name(e);
 611         QSIMPLEQ_INSERT_TAIL(bm_list, bm, entry);
 612     }
 613
 614     if (nb_dir_entries != s->nb_bitmaps) {
 615         error_setg(errp, "Less bitmaps found than specified in header"
 616                          " extension");
 617         goto fail;
 618     }
 619
 620     if ((uint8_t *)e != dir_end) {
 621         goto broken_dir;
 622     }
 623
 624     g_free(dir);
 625     return bm_list;
 626
 627 broken_dir:
 628     ret = -EINVAL;
 629     error_setg(errp, "Broken bitmap directory");
 630
 631 fail:
 632     g_free(dir);
 633     bitmap_list_free(bm_list);
 634
 635     return NULL;
 636 }
 637
 638 int qcow2_check_bitmaps_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
 639                                   void **refcount_table,
 640                                   int64_t *refcount_table_size)
 641 {
 642     int ret;
 643     BDRVQcow2State *s = bs->opaque;
 644     Qcow2BitmapList *bm_list;
 645     Qcow2Bitmap *bm;
 646
 647     if (s->nb_bitmaps == 0) {
 648         return 0;
 649     }
 650
 651     ret = qcow2_inc_refcounts_imrt(bs, res, refcount_table, refcount_table_size,
 652                                    s->bitmap_directory_offset,
 653                                    s->bitmap_directory_size);
 654     if (ret < 0) {
 655         return ret;
 656     }
 657
 658     bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
 659                                s->bitmap_directory_size, NULL);
 660     if (bm_list == NULL) {
 661         res->corruptions++;
 662         return -EINVAL;
 663     }
 664
 665     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
 666         uint64_t *bitmap_table = NULL;
 667         int i;
 668
 669         ret = qcow2_inc_refcounts_imrt(bs, res,
 670                                        refcount_table, refcount_table_size,
 671                                        bm->table.offset,
 672                                        bm->table.size * sizeof(uint64_t));
 673         if (ret < 0) {
 674             goto out;
 675         }
 676
 677         ret = bitmap_table_load(bs, &bm->table, &bitmap_table);
 678         if (ret < 0) {
 679             res->corruptions++;
 680             goto out;
 681         }
 682
 683         for (i = 0; i < bm->table.size; ++i) {
 684             uint64_t entry = bitmap_table[i];
 685             uint64_t offset = entry & BME_TABLE_ENTRY_OFFSET_MASK;
 686
 687             if (check_table_entry(entry, s->cluster_size) < 0) {
 688                 res->corruptions++;
 689                 continue;
 690             }
 691
 692             if (offset == 0) {
 693                 continue;
 694             }
 695
 696             ret = qcow2_inc_refcounts_imrt(bs, res,
 697                                            refcount_table, refcount_table_size,
 698                                            offset, s->cluster_size);
 699             if (ret < 0) {
 700                 g_free(bitmap_table);
 701                 goto out;
 702             }
 703         }
 704
 705         g_free(bitmap_table);
 706     }
 707
 708 out:
 709     bitmap_list_free(bm_list);
 710
 711     return ret;
 712 }
 713
 714 /* bitmap_list_store
 715  * Store bitmap list to qcow2 image as a bitmap directory.
 716  * Everything is checked.
 717  */
 718 static int bitmap_list_store(BlockDriverState *bs, Qcow2BitmapList *bm_list,
 719                              uint64_t *offset, uint64_t *size, bool in_place)
 720 {
 721     int ret;
 722     uint8_t *dir;
 723     int64_t dir_offset = 0;
 724     uint64_t dir_size = 0;
 725     Qcow2Bitmap *bm;
 726     Qcow2BitmapDirEntry *e;
 727
 728     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
 729         dir_size += calc_dir_entry_size(strlen(bm->name), 0);
 730     }
 731
 732     if (dir_size == 0 || dir_size > QCOW2_MAX_BITMAP_DIRECTORY_SIZE) {
 733         return -EINVAL;
 734     }
 735
 736     if (in_place) {
 737         if (*size != dir_size || *offset == 0) {
 738             return -EINVAL;
 739         }
 740
 741         dir_offset = *offset;
 742     }
 743
 744     dir = g_try_malloc(dir_size);
 745     if (dir == NULL) {
 746         return -ENOMEM;
 747     }
 748
 749     e = (Qcow2BitmapDirEntry *)dir;
 750     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
 751         e->bitmap_table_offset = bm->table.offset;
 752         e->bitmap_table_size = bm->table.size;
 753         e->flags = bm->flags;
 754         e->type = BT_DIRTY_TRACKING_BITMAP;
 755         e->granularity_bits = bm->granularity_bits;
 756         e->name_size = strlen(bm->name);
 757         e->extra_data_size = 0;
 758         memcpy(e + 1, bm->name, e->name_size);
 759
 760         if (check_dir_entry(bs, e) < 0) {
 761             ret = -EINVAL;
 762             goto fail;
 763         }
 764
 765         e = next_dir_entry(e);
 766     }
 767
 768     bitmap_directory_to_be(dir, dir_size);
 769
 770     if (!in_place) {
 771         dir_offset = qcow2_alloc_clusters(bs, dir_size);
 772         if (dir_offset < 0) {
 773             ret = dir_offset;
 774             goto fail;
 775         }
 776     }
 777
 778     ret = qcow2_pre_write_overlap_check(bs, 0, dir_offset, dir_size);
 779     if (ret < 0) {
 780         goto fail;
 781     }
 782
 783     ret = bdrv_pwrite(bs->file, dir_offset, dir, dir_size);
 784     if (ret < 0) {
 785         goto fail;
 786     }
 787
 788     g_free(dir);
 789
 790     if (!in_place) {
 791         *size = dir_size;
 792         *offset = dir_offset;
 793     }
 794
 795     return 0;
 796
 797 fail:
 798     g_free(dir);
 799
 800     if (!in_place && dir_offset > 0) {
 801         qcow2_free_clusters(bs, dir_offset, dir_size, QCOW2_DISCARD_OTHER);
 802     }
 803
 804     return ret;
 805 }
 806
 807 /*
 808  * Bitmap List end
 809  */
 810
 811 static int update_ext_header_and_dir_in_place(BlockDriverState *bs,
 812                                               Qcow2BitmapList *bm_list)
 813 {
 814     BDRVQcow2State *s = bs->opaque;
 815     int ret;
 816
 817     if (!(s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS) ||
 818         bm_list == NULL || QSIMPLEQ_EMPTY(bm_list) ||
 819         bitmap_list_count(bm_list) != s->nb_bitmaps)
 820     {
 821         return -EINVAL;
 822     }
 823
 824     s->autoclear_features &= ~(uint64_t)QCOW2_AUTOCLEAR_BITMAPS;
 825     ret = update_header_sync(bs);
 826     if (ret < 0) {
 827         /* Two variants are possible here:
 828          * 1. Autoclear flag is dropped, all bitmaps will be lost.
 829          * 2. Autoclear flag is not dropped, old state is left.
 830          */
 831         return ret;
 832     }
 833
 834     /* autoclear bit is not set, so we can safely update bitmap directory */
 835
 836     ret = bitmap_list_store(bs, bm_list, &s->bitmap_directory_offset,
 837                             &s->bitmap_directory_size, true);
 838     if (ret < 0) {
 839         /* autoclear bit is cleared, so all leaked clusters would be removed on
 840          * qemu-img check */
 841         return ret;
 842     }
 843
 844     ret = update_header_sync(bs);
 845     if (ret < 0) {
 846         /* autoclear bit is cleared, so all leaked clusters would be removed on
 847          * qemu-img check */
 848         return ret;
 849     }
 850
 851     s->autoclear_features |= QCOW2_AUTOCLEAR_BITMAPS;
 852     return update_header_sync(bs);
 853     /* If final update_header_sync() fails, two variants are possible:
 854      * 1. Autoclear flag is not set, all bitmaps will be lost.
 855      * 2. Autoclear flag is set, header and directory are successfully updated.
 856      */
 857 }
 858
 859 static int update_ext_header_and_dir(BlockDriverState *bs,
 860                                      Qcow2BitmapList *bm_list)
 861 {
 862     BDRVQcow2State *s = bs->opaque;
 863     int ret;
 864     uint64_t new_offset = 0;
 865     uint64_t new_size = 0;
 866     uint32_t new_nb_bitmaps = 0;
 867     uint64_t old_offset = s->bitmap_directory_offset;
 868     uint64_t old_size = s->bitmap_directory_size;
 869     uint32_t old_nb_bitmaps = s->nb_bitmaps;
 870     uint64_t old_autocl = s->autoclear_features;
 871
 872     if (bm_list != NULL && !QSIMPLEQ_EMPTY(bm_list)) {
 873         new_nb_bitmaps = bitmap_list_count(bm_list);
 874
 875         if (new_nb_bitmaps > QCOW2_MAX_BITMAPS) {
 876             return -EINVAL;
 877         }
 878
 879         ret = bitmap_list_store(bs, bm_list, &new_offset, &new_size, false);
 880         if (ret < 0) {
 881             return ret;
 882         }
 883
 884         ret = bdrv_flush(bs->file->bs);
 885         if (ret < 0) {
 886             goto fail;
 887         }
 888
 889         s->autoclear_features |= QCOW2_AUTOCLEAR_BITMAPS;
 890     } else {
 891         s->autoclear_features &= ~(uint64_t)QCOW2_AUTOCLEAR_BITMAPS;
 892     }
 893
 894     s->bitmap_directory_offset = new_offset;
 895     s->bitmap_directory_size = new_size;
 896     s->nb_bitmaps = new_nb_bitmaps;
 897
 898     ret = update_header_sync(bs);
 899     if (ret < 0) {
 900         goto fail;
 901     }
 902
 903     if (old_size > 0) {
 904         qcow2_free_clusters(bs, old_offset, old_size, QCOW2_DISCARD_OTHER);
 905     }
 906
 907     return 0;
 908
 909 fail:
 910     if (new_offset > 0) {
 911         qcow2_free_clusters(bs, new_offset, new_size, QCOW2_DISCARD_OTHER);
 912     }
 913
 914     s->bitmap_directory_offset = old_offset;
 915     s->bitmap_directory_size = old_size;
 916     s->nb_bitmaps = old_nb_bitmaps;
 917     s->autoclear_features = old_autocl;
 918
 919     return ret;
 920 }
 921
 922 /* for g_slist_foreach for GSList of BdrvDirtyBitmap* elements */
 923 static void release_dirty_bitmap_helper(gpointer bitmap,
 924                                         gpointer bs)
 925 {
 926     bdrv_release_dirty_bitmap(bs, bitmap);
 927 }
 928
 929 /* for g_slist_foreach for GSList of BdrvDirtyBitmap* elements */
 930 static void set_readonly_helper(gpointer bitmap, gpointer value)
 931 {
 932     bdrv_dirty_bitmap_set_readonly(bitmap, (bool)value);
 933 }
 934
 935 /* qcow2_load_autoloading_dirty_bitmaps()
 936  * Return value is a hint for caller: true means that the Qcow2 header was
 937  * updated. (false doesn't mean that the header should be updated by the
 938  * caller, it just means that updating was not needed or the image cannot be
 939  * written to).
 940  * On failure the function returns false.
 941  */
 942 bool qcow2_load_autoloading_dirty_bitmaps(BlockDriverState *bs, Error **errp)
 943 {
 944     BDRVQcow2State *s = bs->opaque;
 945     Qcow2BitmapList *bm_list;
 946     Qcow2Bitmap *bm;
 947     GSList *created_dirty_bitmaps = NULL;
 948     bool header_updated = false;
 949
 950     if (s->nb_bitmaps == 0) {
 951         /* No bitmaps - nothing to do */
 952         return false;
 953     }
 954
 955     bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
 956                                s->bitmap_directory_size, errp);
 957     if (bm_list == NULL) {
 958         return false;
 959     }
 960
 961     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
 962         if ((bm->flags & BME_FLAG_AUTO) && !(bm->flags & BME_FLAG_IN_USE)) {
 963             BdrvDirtyBitmap *bitmap = load_bitmap(bs, bm, errp);
 964             if (bitmap == NULL) {
 965                 goto fail;
 966             }
 967
 968             bdrv_dirty_bitmap_set_persistance(bitmap, true);
 969             bdrv_dirty_bitmap_set_autoload(bitmap, true);
 970             bm->flags |= BME_FLAG_IN_USE;
 971             created_dirty_bitmaps =
 972                     g_slist_append(created_dirty_bitmaps, bitmap);
 973         }
 974     }
 975
 976     if (created_dirty_bitmaps != NULL) {
 977         if (can_write(bs)) {
 978             /* in_use flags must be updated */
 979             int ret = update_ext_header_and_dir_in_place(bs, bm_list);
 980             if (ret < 0) {
 981                 error_setg_errno(errp, -ret, "Can't update bitmap directory");
 982                 goto fail;
 983             }
 984             header_updated = true;
 985         } else {
 986             g_slist_foreach(created_dirty_bitmaps, set_readonly_helper,
 987                             (gpointer)true);
 988         }
 989     }
 990
 991     g_slist_free(created_dirty_bitmaps);
 992     bitmap_list_free(bm_list);
 993
 994     return header_updated;
 995
 996 fail:
 997     g_slist_foreach(created_dirty_bitmaps, release_dirty_bitmap_helper, bs);
 998     g_slist_free(created_dirty_bitmaps);
 999     bitmap_list_free(bm_list);
1000
1001     return false;
1002 }
1003
1004 int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
1005 {
1006     BDRVQcow2State *s = bs->opaque;
1007     Qcow2BitmapList *bm_list;
1008     Qcow2Bitmap *bm;
1009     GSList *ro_dirty_bitmaps = NULL;
1010     int ret = 0;
1011
1012     if (s->nb_bitmaps == 0) {
1013         /* No bitmaps - nothing to do */
1014         return 0;
1015     }
1016
1017     if (!can_write(bs)) {
1018         error_setg(errp, "Can't write to the image on reopening bitmaps rw");
1019         return -EINVAL;
1020     }
1021
1022     bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
1023                                s->bitmap_directory_size, errp);
1024     if (bm_list == NULL) {
1025         return -EINVAL;
1026     }
1027
1028     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
1029         if (!(bm->flags & BME_FLAG_IN_USE)) {
1030             BdrvDirtyBitmap *bitmap = bdrv_find_dirty_bitmap(bs, bm->name);
1031             if (bitmap == NULL) {
1032                 continue;
1033             }
1034
1035             if (!bdrv_dirty_bitmap_readonly(bitmap)) {
1036                 error_setg(errp, "Bitmap %s is not readonly but not marked"
1037                                  "'IN_USE' in the image. Something went wrong,"
1038                                  "all the bitmaps may be corrupted", bm->name);
1039                 ret = -EINVAL;
1040                 goto out;
1041             }
1042
1043             bm->flags |= BME_FLAG_IN_USE;
1044             ro_dirty_bitmaps = g_slist_append(ro_dirty_bitmaps, bitmap);
1045         }
1046     }
1047
1048     if (ro_dirty_bitmaps != NULL) {
1049         /* in_use flags must be updated */
1050         ret = update_ext_header_and_dir_in_place(bs, bm_list);
1051         if (ret < 0) {
1052             error_setg_errno(errp, -ret, "Can't update bitmap directory");
1053             goto out;
1054         }
1055         g_slist_foreach(ro_dirty_bitmaps, set_readonly_helper, false);
1056     }
1057
1058 out:
1059     g_slist_free(ro_dirty_bitmaps);
1060     bitmap_list_free(bm_list);
1061
1062     return ret;
1063 }
1064
1065 /* store_bitmap_data()
1066  * Store bitmap to image, filling bitmap table accordingly.
1067  */
1068 static uint64_t *store_bitmap_data(BlockDriverState *bs,
1069                                    BdrvDirtyBitmap *bitmap,
1070                                    uint32_t *bitmap_table_size, Error **errp)
1071 {
1072     int ret;
1073     BDRVQcow2State *s = bs->opaque;
1074     int64_t sector;
1075     uint64_t sbc;
1076     uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
1077     const char *bm_name = bdrv_dirty_bitmap_name(bitmap);
1078     uint8_t *buf = NULL;
1079     BdrvDirtyBitmapIter *dbi;
1080     uint64_t *tb;
1081     uint64_t tb_size =
1082             size_to_clusters(s,
1083                 bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size));
1084
1085     if (tb_size > BME_MAX_TABLE_SIZE ||
1086         tb_size * s->cluster_size > BME_MAX_PHYS_SIZE)
1087     {
1088         error_setg(errp, "Bitmap '%s' is too big", bm_name);
1089         return NULL;
1090     }
1091
1092     tb = g_try_new0(uint64_t, tb_size);
1093     if (tb == NULL) {
1094         error_setg(errp, "No memory");
1095         return NULL;
1096     }
1097
1098     dbi = bdrv_dirty_iter_new(bitmap, 0);
1099     buf = g_malloc(s->cluster_size);
1100     sbc = sectors_covered_by_bitmap_cluster(s, bitmap);
1101     assert(DIV_ROUND_UP(bm_size, sbc) == tb_size);
1102
1103     while ((sector = bdrv_dirty_iter_next(dbi)) != -1) {
1104         uint64_t cluster = sector / sbc;
1105         uint64_t end, write_size;
1106         int64_t off;
1107
1108         sector = cluster * sbc;
1109         end = MIN(bm_size, sector + sbc);
1110         write_size =
1111             bdrv_dirty_bitmap_serialization_size(bitmap, sector, end - sector);
1112         assert(write_size <= s->cluster_size);
1113
1114         off = qcow2_alloc_clusters(bs, s->cluster_size);
1115         if (off < 0) {
1116             error_setg_errno(errp, -off,
1117                              "Failed to allocate clusters for bitmap '%s'",
1118                              bm_name);
1119             goto fail;
1120         }
1121         tb[cluster] = off;
1122
1123         bdrv_dirty_bitmap_serialize_part(bitmap, buf, sector, end - sector);
1124         if (write_size < s->cluster_size) {
1125             memset(buf + write_size, 0, s->cluster_size - write_size);
1126         }
1127
1128         ret = qcow2_pre_write_overlap_check(bs, 0, off, s->cluster_size);
1129         if (ret < 0) {
1130             error_setg_errno(errp, -ret, "Qcow2 overlap check failed");
1131             goto fail;
1132         }
1133
1134         ret = bdrv_pwrite(bs->file, off, buf, s->cluster_size);
1135         if (ret < 0) {
1136             error_setg_errno(errp, -ret, "Failed to write bitmap '%s' to file",
1137                              bm_name);
1138             goto fail;
1139         }
1140
1141         if (end >= bm_size) {
1142             break;
1143         }
1144
1145         bdrv_set_dirty_iter(dbi, end);
1146     }
1147
1148     *bitmap_table_size = tb_size;
1149     g_free(buf);
1150     bdrv_dirty_iter_free(dbi);
1151
1152     return tb;
1153
1154 fail:
1155     clear_bitmap_table(bs, tb, tb_size);
1156     g_free(buf);
1157     bdrv_dirty_iter_free(dbi);
1158     g_free(tb);
1159
1160     return NULL;
1161 }
1162
1163 /* store_bitmap()
1164  * Store bm->dirty_bitmap to qcow2.
1165  * Set bm->table_offset and bm->table_size accordingly.
1166  */
1167 static int store_bitmap(BlockDriverState *bs, Qcow2Bitmap *bm, Error **errp)
1168 {
1169     int ret;
1170     uint64_t *tb;
1171     int64_t tb_offset;
1172     uint32_t tb_size;
1173     BdrvDirtyBitmap *bitmap = bm->dirty_bitmap;
1174     const char *bm_name;
1175
1176     assert(bitmap != NULL);
1177
1178     bm_name = bdrv_dirty_bitmap_name(bitmap);
1179
1180     tb = store_bitmap_data(bs, bitmap, &tb_size, errp);
1181     if (tb == NULL) {
1182         return -EINVAL;
1183     }
1184
1185     assert(tb_size <= BME_MAX_TABLE_SIZE);
1186     tb_offset = qcow2_alloc_clusters(bs, tb_size * sizeof(tb[0]));
1187     if (tb_offset < 0) {
1188         error_setg_errno(errp, -tb_offset,
1189                          "Failed to allocate clusters for bitmap '%s'",
1190                          bm_name);
1191         ret = tb_offset;
1192         goto fail;
1193     }
1194
1195     ret = qcow2_pre_write_overlap_check(bs, 0, tb_offset,
1196                                         tb_size * sizeof(tb[0]));
1197     if (ret < 0) {
1198         error_setg_errno(errp, -ret, "Qcow2 overlap check failed");
1199         goto fail;
1200     }
1201
1202     bitmap_table_to_be(tb, tb_size);
1203     ret = bdrv_pwrite(bs->file, tb_offset, tb, tb_size * sizeof(tb[0]));
1204     if (ret < 0) {
1205         error_setg_errno(errp, -ret, "Failed to write bitmap '%s' to file",
1206                          bm_name);
1207         goto fail;
1208     }
1209
1210     g_free(tb);
1211
1212     bm->table.offset = tb_offset;
1213     bm->table.size = tb_size;
1214
1215     return 0;
1216
1217 fail:
1218     clear_bitmap_table(bs, tb, tb_size);
1219
1220     if (tb_offset > 0) {
1221         qcow2_free_clusters(bs, tb_offset, tb_size * sizeof(tb[0]),
1222                             QCOW2_DISCARD_OTHER);
1223     }
1224
1225     g_free(tb);
1226
1227     return ret;
1228 }
1229
1230 static Qcow2Bitmap *find_bitmap_by_name(Qcow2BitmapList *bm_list,
1231                                         const char *name)
1232 {
1233     Qcow2Bitmap *bm;
1234
1235     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
1236         if (strcmp(name, bm->name) == 0) {
1237             return bm;
1238         }
1239     }
1240
1241     return NULL;
1242 }
1243
1244 void qcow2_remove_persistent_dirty_bitmap(BlockDriverState *bs,
1245                                           const char *name,
1246                                           Error **errp)
1247 {
1248     int ret;
1249     BDRVQcow2State *s = bs->opaque;
1250     Qcow2Bitmap *bm;
1251     Qcow2BitmapList *bm_list;
1252
1253     if (s->nb_bitmaps == 0) {
1254         /* Absence of the bitmap is not an error: see explanation above
1255          * bdrv_remove_persistent_dirty_bitmap() definition. */
1256         return;
1257     }
1258
1259     bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
1260                                s->bitmap_directory_size, errp);
1261     if (bm_list == NULL) {
1262         return;
1263     }
1264
1265     bm = find_bitmap_by_name(bm_list, name);
1266     if (bm == NULL) {
1267         goto fail;
1268     }
1269
1270     QSIMPLEQ_REMOVE(bm_list, bm, Qcow2Bitmap, entry);
1271
1272     ret = update_ext_header_and_dir(bs, bm_list);
1273     if (ret < 0) {
1274         error_setg_errno(errp, -ret, "Failed to update bitmap extension");
1275         goto fail;
1276     }
1277
1278     free_bitmap_clusters(bs, &bm->table);
1279
1280 fail:
1281     bitmap_free(bm);
1282     bitmap_list_free(bm_list);
1283 }
1284
1285 void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp)
1286 {
1287     BdrvDirtyBitmap *bitmap;
1288     BDRVQcow2State *s = bs->opaque;
1289     uint32_t new_nb_bitmaps = s->nb_bitmaps;
1290     uint64_t new_dir_size = s->bitmap_directory_size;
1291     int ret;
1292     Qcow2BitmapList *bm_list;
1293     Qcow2Bitmap *bm;
1294     Qcow2BitmapTableList drop_tables;
1295     Qcow2BitmapTable *tb, *tb_next;
1296
1297     if (!bdrv_has_changed_persistent_bitmaps(bs)) {
1298         /* nothing to do */
1299         return;
1300     }
1301
1302     if (!can_write(bs)) {
1303         error_setg(errp, "No write access");
1304         return;
1305     }
1306
1307     QSIMPLEQ_INIT(&drop_tables);
1308
1309     if (s->nb_bitmaps == 0) {
1310         bm_list = bitmap_list_new();
1311     } else {
1312         bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
1313                                    s->bitmap_directory_size, errp);
1314         if (bm_list == NULL) {
1315             return;
1316         }
1317     }
1318
1319     /* check constraints and names */
1320     for (bitmap = bdrv_dirty_bitmap_next(bs, NULL); bitmap != NULL;
1321          bitmap = bdrv_dirty_bitmap_next(bs, bitmap))
1322     {
1323         const char *name = bdrv_dirty_bitmap_name(bitmap);
1324         uint32_t granularity = bdrv_dirty_bitmap_granularity(bitmap);
1325         Qcow2Bitmap *bm;
1326
1327         if (!bdrv_dirty_bitmap_get_persistance(bitmap) ||
1328             bdrv_dirty_bitmap_readonly(bitmap))
1329         {
1330             continue;
1331         }
1332
1333         if (check_constraints_on_bitmap(bs, name, granularity, errp) < 0) {
1334             error_prepend(errp, "Bitmap '%s' doesn't satisfy the constraints: ",
1335                           name);
1336             goto fail;
1337         }
1338
1339         bm = find_bitmap_by_name(bm_list, name);
1340         if (bm == NULL) {
1341             if (++new_nb_bitmaps > QCOW2_MAX_BITMAPS) {
1342                 error_setg(errp, "Too many persistent bitmaps");
1343                 goto fail;
1344             }
1345
1346             new_dir_size += calc_dir_entry_size(strlen(name), 0);
1347             if (new_dir_size > QCOW2_MAX_BITMAP_DIRECTORY_SIZE) {
1348                 error_setg(errp, "Bitmap directory is too large");
1349                 goto fail;
1350             }
1351
1352             bm = g_new0(Qcow2Bitmap, 1);
1353             bm->name = g_strdup(name);
1354             QSIMPLEQ_INSERT_TAIL(bm_list, bm, entry);
1355         } else {
1356             if (!(bm->flags & BME_FLAG_IN_USE)) {
1357                 error_setg(errp, "Bitmap '%s' already exists in the image",
1358                            name);
1359                 goto fail;
1360             }
1361             tb = g_memdup(&bm->table, sizeof(bm->table));
1362             bm->table.offset = 0;
1363             bm->table.size = 0;
1364             QSIMPLEQ_INSERT_TAIL(&drop_tables, tb, entry);
1365         }
1366         bm->flags = bdrv_dirty_bitmap_get_autoload(bitmap) ? BME_FLAG_AUTO : 0;
1367         bm->granularity_bits = ctz32(bdrv_dirty_bitmap_granularity(bitmap));
1368         bm->dirty_bitmap = bitmap;
1369     }
1370
1371     /* allocate clusters and store bitmaps */
1372     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
1373         if (bm->dirty_bitmap == NULL) {
1374             continue;
1375         }
1376
1377         ret = store_bitmap(bs, bm, errp);
1378         if (ret < 0) {
1379             goto fail;
1380         }
1381     }
1382
1383     ret = update_ext_header_and_dir(bs, bm_list);
1384     if (ret < 0) {
1385         error_setg_errno(errp, -ret, "Failed to update bitmap extension");
1386         goto fail;
1387     }
1388
1389     /* Bitmap directory was successfully updated, so, old data can be dropped.
1390      * TODO it is better to reuse these clusters */
1391     QSIMPLEQ_FOREACH_SAFE(tb, &drop_tables, entry, tb_next) {
1392         free_bitmap_clusters(bs, tb);
1393         g_free(tb);
1394     }
1395
1396     bitmap_list_free(bm_list);
1397     return;
1398
1399 fail:
1400     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
1401         if (bm->dirty_bitmap == NULL || bm->table.offset == 0) {
1402             continue;
1403         }
1404
1405         free_bitmap_clusters(bs, &bm->table);
1406     }
1407
1408     QSIMPLEQ_FOREACH_SAFE(tb, &drop_tables, entry, tb_next) {
1409         g_free(tb);
1410     }
1411
1412     bitmap_list_free(bm_list);
1413 }
1414
1415 int qcow2_reopen_bitmaps_ro(BlockDriverState *bs, Error **errp)
1416 {
1417     BdrvDirtyBitmap *bitmap;
1418     Error *local_err = NULL;
1419
1420     qcow2_store_persistent_dirty_bitmaps(bs, &local_err);
1421     if (local_err != NULL) {
1422         error_propagate(errp, local_err);
1423         return -EINVAL;
1424     }
1425
1426     for (bitmap = bdrv_dirty_bitmap_next(bs, NULL); bitmap != NULL;
1427          bitmap = bdrv_dirty_bitmap_next(bs, bitmap))
1428     {
1429         if (bdrv_dirty_bitmap_get_persistance(bitmap)) {
1430             bdrv_dirty_bitmap_set_readonly(bitmap, true);
1431         }
1432     }
1433
1434     return 0;
1435 }
1436
1437 bool qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs,
1438                                       const char *name,
1439                                       uint32_t granularity,
1440                                       Error **errp)
1441 {
1442     BDRVQcow2State *s = bs->opaque;
1443     bool found;
1444     Qcow2BitmapList *bm_list;
1445
1446     if (check_constraints_on_bitmap(bs, name, granularity, errp) != 0) {
1447         goto fail;
1448     }
1449
1450     if (s->nb_bitmaps == 0) {
1451         return true;
1452     }
1453
1454     if (s->nb_bitmaps >= QCOW2_MAX_BITMAPS) {
1455         error_setg(errp,
1456                    "Maximum number of persistent bitmaps is already reached");
1457         goto fail;
1458     }
1459
1460     if (s->bitmap_directory_size + calc_dir_entry_size(strlen(name), 0) >
1461         QCOW2_MAX_BITMAP_DIRECTORY_SIZE)
1462     {
1463         error_setg(errp, "Not enough space in the bitmap directory");
1464         goto fail;
1465     }
1466
1467     bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
1468                                s->bitmap_directory_size, errp);
1469     if (bm_list == NULL) {
1470         goto fail;
1471     }
1472
1473     found = find_bitmap_by_name(bm_list, name);
1474     bitmap_list_free(bm_list);
1475     if (found) {
1476         error_setg(errp, "Bitmap with the same name is already stored");
1477         goto fail;
1478     }
1479
1480     return true;
1481
1482 fail:
1483     error_prepend(errp, "Can't make bitmap '%s' persistent in '%s': ",
1484                   name, bdrv_get_device_or_node_name(bs));
1485     return false;
1486 }