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 "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
  81 typedef struct Qcow2Bitmap {
  82     Qcow2BitmapTable table;
  83     uint32_t flags;
  84     uint8_t granularity_bits;
  85     char *name;
  86
  87     BdrvDirtyBitmap *dirty_bitmap;
  88
  89     QSIMPLEQ_ENTRY(Qcow2Bitmap) entry;
  90 } Qcow2Bitmap;
  91 typedef QSIMPLEQ_HEAD(Qcow2BitmapList, Qcow2Bitmap) Qcow2BitmapList;
  92
  93 typedef enum BitmapType {
  94     BT_DIRTY_TRACKING_BITMAP = 1
  95 } BitmapType;
  96
  97 static inline bool can_write(BlockDriverState *bs)
  98 {
  99     return !bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE);
 100 }
 101
 102 static int update_header_sync(BlockDriverState *bs)
 103 {
 104     int ret;
 105
 106     ret = qcow2_update_header(bs);
 107     if (ret < 0) {
 108         return ret;
 109     }
 110
 111     return bdrv_flush(bs->file->bs);
 112 }
 113
 114 static inline void bitmap_table_to_be(uint64_t *bitmap_table, size_t size)
 115 {
 116     size_t i;
 117
 118     for (i = 0; i < size; ++i) {
 119         bitmap_table[i] = cpu_to_be64(bitmap_table[i]);
 120     }
 121 }
 122
 123 static int check_table_entry(uint64_t entry, int cluster_size)
 124 {
 125     uint64_t offset;
 126
 127     if (entry & BME_TABLE_ENTRY_RESERVED_MASK) {
 128         return -EINVAL;
 129     }
 130
 131     offset = entry & BME_TABLE_ENTRY_OFFSET_MASK;
 132     if (offset != 0) {
 133         /* if offset specified, bit 0 is reserved */
 134         if (entry & BME_TABLE_ENTRY_FLAG_ALL_ONES) {
 135             return -EINVAL;
 136         }
 137
 138         if (offset % cluster_size != 0) {
 139             return -EINVAL;
 140         }
 141     }
 142
 143     return 0;
 144 }
 145
 146 static int check_constraints_on_bitmap(BlockDriverState *bs,
 147                                        const char *name,
 148                                        uint32_t granularity,
 149                                        Error **errp)
 150 {
 151     BDRVQcow2State *s = bs->opaque;
 152     int granularity_bits = ctz32(granularity);
 153     int64_t len = bdrv_getlength(bs);
 154
 155     assert(granularity > 0);
 156     assert((granularity & (granularity - 1)) == 0);
 157
 158     if (len < 0) {
 159         error_setg_errno(errp, -len, "Failed to get size of '%s'",
 160                          bdrv_get_device_or_node_name(bs));
 161         return len;
 162     }
 163
 164     if (granularity_bits > BME_MAX_GRANULARITY_BITS) {
 165         error_setg(errp, "Granularity exceeds maximum (%llu bytes)",
 166                    1ULL << BME_MAX_GRANULARITY_BITS);
 167         return -EINVAL;
 168     }
 169     if (granularity_bits < BME_MIN_GRANULARITY_BITS) {
 170         error_setg(errp, "Granularity is under minimum (%llu bytes)",
 171                    1ULL << BME_MIN_GRANULARITY_BITS);
 172         return -EINVAL;
 173     }
 174
 175     if ((len > (uint64_t)BME_MAX_PHYS_SIZE << granularity_bits) ||
 176         (len > (uint64_t)BME_MAX_TABLE_SIZE * s->cluster_size <<
 177                granularity_bits))
 178     {
 179         error_setg(errp, "Too much space will be occupied by the bitmap. "
 180                    "Use larger granularity");
 181         return -EINVAL;
 182     }
 183
 184     if (strlen(name) > BME_MAX_NAME_SIZE) {
 185         error_setg(errp, "Name length exceeds maximum (%u characters)",
 186                    BME_MAX_NAME_SIZE);
 187         return -EINVAL;
 188     }
 189
 190     return 0;
 191 }
 192
 193 static void clear_bitmap_table(BlockDriverState *bs, uint64_t *bitmap_table,
 194                                uint32_t bitmap_table_size)
 195 {
 196     BDRVQcow2State *s = bs->opaque;
 197     int i;
 198
 199     for (i = 0; i < bitmap_table_size; ++i) {
 200         uint64_t addr = bitmap_table[i] & BME_TABLE_ENTRY_OFFSET_MASK;
 201         if (!addr) {
 202             continue;
 203         }
 204
 205         qcow2_free_clusters(bs, addr, s->cluster_size, QCOW2_DISCARD_OTHER);
 206         bitmap_table[i] = 0;
 207     }
 208 }
 209
 210 static int bitmap_table_load(BlockDriverState *bs, Qcow2BitmapTable *tb,
 211                              uint64_t **bitmap_table)
 212 {
 213     int ret;
 214     BDRVQcow2State *s = bs->opaque;
 215     uint32_t i;
 216     uint64_t *table;
 217
 218     assert(tb->size != 0);
 219     table = g_try_new(uint64_t, tb->size);
 220     if (table == NULL) {
 221         return -ENOMEM;
 222     }
 223
 224     assert(tb->size <= BME_MAX_TABLE_SIZE);
 225     ret = bdrv_pread(bs->file, tb->offset,
 226                      table, tb->size * sizeof(uint64_t));
 227     if (ret < 0) {
 228         goto fail;
 229     }
 230
 231     for (i = 0; i < tb->size; ++i) {
 232         table[i] = be64_to_cpu(table[i]);
 233         ret = check_table_entry(table[i], s->cluster_size);
 234         if (ret < 0) {
 235             goto fail;
 236         }
 237     }
 238
 239     *bitmap_table = table;
 240     return 0;
 241
 242 fail:
 243     g_free(table);
 244
 245     return ret;
 246 }
 247
 248 static int free_bitmap_clusters(BlockDriverState *bs, Qcow2BitmapTable *tb)
 249 {
 250     int ret;
 251     uint64_t *bitmap_table;
 252
 253     ret = bitmap_table_load(bs, tb, &bitmap_table);
 254     if (ret < 0) {
 255         return ret;
 256     }
 257
 258     clear_bitmap_table(bs, bitmap_table, tb->size);
 259     qcow2_free_clusters(bs, tb->offset, tb->size * sizeof(uint64_t),
 260                         QCOW2_DISCARD_OTHER);
 261     g_free(bitmap_table);
 262
 263     tb->offset = 0;
 264     tb->size = 0;
 265
 266     return 0;
 267 }
 268
 269 /* Return the disk size covered by a single qcow2 cluster of bitmap data. */
 270 static uint64_t bytes_covered_by_bitmap_cluster(const BDRVQcow2State *s,
 271                                                 const BdrvDirtyBitmap *bitmap)
 272 {
 273     uint64_t granularity = bdrv_dirty_bitmap_granularity(bitmap);
 274     uint64_t limit = granularity * (s->cluster_size << 3);
 275
 276     assert(QEMU_IS_ALIGNED(limit,
 277                            bdrv_dirty_bitmap_serialization_align(bitmap)));
 278     return limit;
 279 }
 280
 281 /* load_bitmap_data
 282  * @bitmap_table entries must satisfy specification constraints.
 283  * @bitmap must be cleared */
 284 static int load_bitmap_data(BlockDriverState *bs,
 285                             const uint64_t *bitmap_table,
 286                             uint32_t bitmap_table_size,
 287                             BdrvDirtyBitmap *bitmap)
 288 {
 289     int ret = 0;
 290     BDRVQcow2State *s = bs->opaque;
 291     uint64_t offset, limit;
 292     uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
 293     uint8_t *buf = NULL;
 294     uint64_t i, tab_size =
 295             size_to_clusters(s,
 296                 bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size));
 297
 298     if (tab_size != bitmap_table_size || tab_size > BME_MAX_TABLE_SIZE) {
 299         return -EINVAL;
 300     }
 301
 302     buf = g_malloc(s->cluster_size);
 303     limit = bytes_covered_by_bitmap_cluster(s, bitmap);
 304     for (i = 0, offset = 0; i < tab_size; ++i, offset += limit) {
 305         uint64_t count = MIN(bm_size - offset, limit);
 306         uint64_t entry = bitmap_table[i];
 307         uint64_t data_offset = entry & BME_TABLE_ENTRY_OFFSET_MASK;
 308
 309         assert(check_table_entry(entry, s->cluster_size) == 0);
 310
 311         if (data_offset == 0) {
 312             if (entry & BME_TABLE_ENTRY_FLAG_ALL_ONES) {
 313                 bdrv_dirty_bitmap_deserialize_ones(bitmap, offset, count,
 314                                                    false);
 315             } else {
 316                 /* No need to deserialize zeros because the dirty bitmap is
 317                  * already cleared */
 318             }
 319         } else {
 320             ret = bdrv_pread(bs->file, data_offset, buf, s->cluster_size);
 321             if (ret < 0) {
 322                 goto finish;
 323             }
 324             bdrv_dirty_bitmap_deserialize_part(bitmap, buf, offset, count,
 325                                                false);
 326         }
 327     }
 328     ret = 0;
 329
 330     bdrv_dirty_bitmap_deserialize_finish(bitmap);
 331
 332 finish:
 333     g_free(buf);
 334
 335     return ret;
 336 }
 337
 338 static BdrvDirtyBitmap *load_bitmap(BlockDriverState *bs,
 339                                     Qcow2Bitmap *bm, Error **errp)
 340 {
 341     int ret;
 342     uint64_t *bitmap_table = NULL;
 343     uint32_t granularity;
 344     BdrvDirtyBitmap *bitmap = NULL;
 345
 346     if (bm->flags & BME_FLAG_IN_USE) {
 347         error_setg(errp, "Bitmap '%s' is in use", bm->name);
 348         goto fail;
 349     }
 350
 351     ret = bitmap_table_load(bs, &bm->table, &bitmap_table);
 352     if (ret < 0) {
 353         error_setg_errno(errp, -ret,
 354                          "Could not read bitmap_table table from image for "
 355                          "bitmap '%s'", bm->name);
 356         goto fail;
 357     }
 358
 359     granularity = 1U << bm->granularity_bits;
 360     bitmap = bdrv_create_dirty_bitmap(bs, granularity, bm->name, errp);
 361     if (bitmap == NULL) {
 362         goto fail;
 363     }
 364
 365     ret = load_bitmap_data(bs, bitmap_table, bm->table.size, bitmap);
 366     if (ret < 0) {
 367         error_setg_errno(errp, -ret, "Could not read bitmap '%s' from image",
 368                          bm->name);
 369         goto fail;
 370     }
 371
 372     g_free(bitmap_table);
 373     return bitmap;
 374
 375 fail:
 376     g_free(bitmap_table);
 377     if (bitmap != NULL) {
 378         bdrv_release_dirty_bitmap(bs, bitmap);
 379     }
 380
 381     return NULL;
 382 }
 383
 384 /*
 385  * Bitmap List
 386  */
 387
 388 /*
 389  * Bitmap List private functions
 390  * Only Bitmap List knows about bitmap directory structure in Qcow2.
 391  */
 392
 393 static inline void bitmap_dir_entry_to_cpu(Qcow2BitmapDirEntry *entry)
 394 {
 395     entry->bitmap_table_offset = be64_to_cpu(entry->bitmap_table_offset);
 396     entry->bitmap_table_size = be32_to_cpu(entry->bitmap_table_size);
 397     entry->flags = be32_to_cpu(entry->flags);
 398     entry->name_size = be16_to_cpu(entry->name_size);
 399     entry->extra_data_size = be32_to_cpu(entry->extra_data_size);
 400 }
 401
 402 static inline void bitmap_dir_entry_to_be(Qcow2BitmapDirEntry *entry)
 403 {
 404     entry->bitmap_table_offset = cpu_to_be64(entry->bitmap_table_offset);
 405     entry->bitmap_table_size = cpu_to_be32(entry->bitmap_table_size);
 406     entry->flags = cpu_to_be32(entry->flags);
 407     entry->name_size = cpu_to_be16(entry->name_size);
 408     entry->extra_data_size = cpu_to_be32(entry->extra_data_size);
 409 }
 410
 411 static inline int calc_dir_entry_size(size_t name_size, size_t extra_data_size)
 412 {
 413     int size = sizeof(Qcow2BitmapDirEntry) + name_size + extra_data_size;
 414     return ROUND_UP(size, 8);
 415 }
 416
 417 static inline int dir_entry_size(Qcow2BitmapDirEntry *entry)
 418 {
 419     return calc_dir_entry_size(entry->name_size, entry->extra_data_size);
 420 }
 421
 422 static inline const char *dir_entry_name_field(Qcow2BitmapDirEntry *entry)
 423 {
 424     return (const char *)(entry + 1) + entry->extra_data_size;
 425 }
 426
 427 static inline char *dir_entry_copy_name(Qcow2BitmapDirEntry *entry)
 428 {
 429     const char *name_field = dir_entry_name_field(entry);
 430     return g_strndup(name_field, entry->name_size);
 431 }
 432
 433 static inline Qcow2BitmapDirEntry *next_dir_entry(Qcow2BitmapDirEntry *entry)
 434 {
 435     return (Qcow2BitmapDirEntry *)((uint8_t *)entry + dir_entry_size(entry));
 436 }
 437
 438 static int check_dir_entry(BlockDriverState *bs, Qcow2BitmapDirEntry *entry)
 439 {
 440     BDRVQcow2State *s = bs->opaque;
 441     uint64_t phys_bitmap_bytes;
 442     int64_t len;
 443
 444     bool fail = (entry->bitmap_table_size == 0) ||
 445                 (entry->bitmap_table_offset == 0) ||
 446                 (entry->bitmap_table_offset % s->cluster_size) ||
 447                 (entry->bitmap_table_size > BME_MAX_TABLE_SIZE) ||
 448                 (entry->granularity_bits > BME_MAX_GRANULARITY_BITS) ||
 449                 (entry->granularity_bits < BME_MIN_GRANULARITY_BITS) ||
 450                 (entry->flags & BME_RESERVED_FLAGS) ||
 451                 (entry->name_size > BME_MAX_NAME_SIZE) ||
 452                 (entry->type != BT_DIRTY_TRACKING_BITMAP);
 453
 454     if (fail) {
 455         return -EINVAL;
 456     }
 457
 458     phys_bitmap_bytes = (uint64_t)entry->bitmap_table_size * s->cluster_size;
 459     len = bdrv_getlength(bs);
 460
 461     if (len < 0) {
 462         return len;
 463     }
 464
 465     fail = (phys_bitmap_bytes > BME_MAX_PHYS_SIZE) ||
 466            (len > ((phys_bitmap_bytes * 8) << entry->granularity_bits));
 467
 468     return fail ? -EINVAL : 0;
 469 }
 470
 471 static inline void bitmap_directory_to_be(uint8_t *dir, size_t size)
 472 {
 473     uint8_t *end = dir + size;
 474     while (dir < end) {
 475         Qcow2BitmapDirEntry *e = (Qcow2BitmapDirEntry *)dir;
 476         dir += dir_entry_size(e);
 477
 478         bitmap_dir_entry_to_be(e);
 479     }
 480 }
 481
 482 /*
 483  * Bitmap List public functions
 484  */
 485
 486 static void bitmap_free(Qcow2Bitmap *bm)
 487 {
 488     if (bm == NULL) {
 489         return;
 490     }
 491
 492     g_free(bm->name);
 493     g_free(bm);
 494 }
 495
 496 static void bitmap_list_free(Qcow2BitmapList *bm_list)
 497 {
 498     Qcow2Bitmap *bm;
 499
 500     if (bm_list == NULL) {
 501         return;
 502     }
 503
 504     while ((bm = QSIMPLEQ_FIRST(bm_list)) != NULL) {
 505         QSIMPLEQ_REMOVE_HEAD(bm_list, entry);
 506         bitmap_free(bm);
 507     }
 508
 509     g_free(bm_list);
 510 }
 511
 512 static Qcow2BitmapList *bitmap_list_new(void)
 513 {
 514     Qcow2BitmapList *bm_list = g_new(Qcow2BitmapList, 1);
 515     QSIMPLEQ_INIT(bm_list);
 516
 517     return bm_list;
 518 }
 519
 520 static uint32_t bitmap_list_count(Qcow2BitmapList *bm_list)
 521 {
 522     Qcow2Bitmap *bm;
 523     uint32_t nb_bitmaps = 0;
 524
 525     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
 526         nb_bitmaps++;
 527     }
 528
 529     return nb_bitmaps;
 530 }
 531
 532 /* bitmap_list_load
 533  * Get bitmap list from qcow2 image. Actually reads bitmap directory,
 534  * checks it and convert to bitmap list.
 535  */
 536 static Qcow2BitmapList *bitmap_list_load(BlockDriverState *bs, uint64_t offset,
 537                                          uint64_t size, Error **errp)
 538 {
 539     int ret;
 540     BDRVQcow2State *s = bs->opaque;
 541     uint8_t *dir, *dir_end;
 542     Qcow2BitmapDirEntry *e;
 543     uint32_t nb_dir_entries = 0;
 544     Qcow2BitmapList *bm_list = NULL;
 545
 546     if (size == 0) {
 547         error_setg(errp, "Requested bitmap directory size is zero");
 548         return NULL;
 549     }
 550
 551     if (size > QCOW2_MAX_BITMAP_DIRECTORY_SIZE) {
 552         error_setg(errp, "Requested bitmap directory size is too big");
 553         return NULL;
 554     }
 555
 556     dir = g_try_malloc(size);
 557     if (dir == NULL) {
 558         error_setg(errp, "Failed to allocate space for bitmap directory");
 559         return NULL;
 560     }
 561     dir_end = dir + size;
 562
 563     ret = bdrv_pread(bs->file, offset, dir, size);
 564     if (ret < 0) {
 565         error_setg_errno(errp, -ret, "Failed to read bitmap directory");
 566         goto fail;
 567     }
 568
 569     bm_list = bitmap_list_new();
 570     for (e = (Qcow2BitmapDirEntry *)dir;
 571          e < (Qcow2BitmapDirEntry *)dir_end;
 572          e = next_dir_entry(e))
 573     {
 574         Qcow2Bitmap *bm;
 575
 576         if ((uint8_t *)(e + 1) > dir_end) {
 577             goto broken_dir;
 578         }
 579
 580         if (++nb_dir_entries > s->nb_bitmaps) {
 581             error_setg(errp, "More bitmaps found than specified in header"
 582                        " extension");
 583             goto fail;
 584         }
 585         bitmap_dir_entry_to_cpu(e);
 586
 587         if ((uint8_t *)next_dir_entry(e) > dir_end) {
 588             goto broken_dir;
 589         }
 590
 591         if (e->extra_data_size != 0) {
 592             error_setg(errp, "Bitmap extra data is not supported");
 593             goto fail;
 594         }
 595
 596         ret = check_dir_entry(bs, e);
 597         if (ret < 0) {
 598             error_setg(errp, "Bitmap '%.*s' doesn't satisfy the constraints",
 599                        e->name_size, dir_entry_name_field(e));
 600             goto fail;
 601         }
 602
 603         bm = g_new0(Qcow2Bitmap, 1);
 604         bm->table.offset = e->bitmap_table_offset;
 605         bm->table.size = e->bitmap_table_size;
 606         bm->flags = e->flags;
 607         bm->granularity_bits = e->granularity_bits;
 608         bm->name = dir_entry_copy_name(e);
 609         QSIMPLEQ_INSERT_TAIL(bm_list, bm, entry);
 610     }
 611
 612     if (nb_dir_entries != s->nb_bitmaps) {
 613         error_setg(errp, "Less bitmaps found than specified in header"
 614                          " extension");
 615         goto fail;
 616     }
 617
 618     if ((uint8_t *)e != dir_end) {
 619         goto broken_dir;
 620     }
 621
 622     g_free(dir);
 623     return bm_list;
 624
 625 broken_dir:
 626     ret = -EINVAL;
 627     error_setg(errp, "Broken bitmap directory");
 628
 629 fail:
 630     g_free(dir);
 631     bitmap_list_free(bm_list);
 632
 633     return NULL;
 634 }
 635
 636 int qcow2_check_bitmaps_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
 637                                   void **refcount_table,
 638                                   int64_t *refcount_table_size)
 639 {
 640     int ret;
 641     BDRVQcow2State *s = bs->opaque;
 642     Qcow2BitmapList *bm_list;
 643     Qcow2Bitmap *bm;
 644
 645     if (s->nb_bitmaps == 0) {
 646         return 0;
 647     }
 648
 649     ret = qcow2_inc_refcounts_imrt(bs, res, refcount_table, refcount_table_size,
 650                                    s->bitmap_directory_offset,
 651                                    s->bitmap_directory_size);
 652     if (ret < 0) {
 653         return ret;
 654     }
 655
 656     bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
 657                                s->bitmap_directory_size, NULL);
 658     if (bm_list == NULL) {
 659         res->corruptions++;
 660         return -EINVAL;
 661     }
 662
 663     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
 664         uint64_t *bitmap_table = NULL;
 665         int i;
 666
 667         ret = qcow2_inc_refcounts_imrt(bs, res,
 668                                        refcount_table, refcount_table_size,
 669                                        bm->table.offset,
 670                                        bm->table.size * sizeof(uint64_t));
 671         if (ret < 0) {
 672             goto out;
 673         }
 674
 675         ret = bitmap_table_load(bs, &bm->table, &bitmap_table);
 676         if (ret < 0) {
 677             res->corruptions++;
 678             goto out;
 679         }
 680
 681         for (i = 0; i < bm->table.size; ++i) {
 682             uint64_t entry = bitmap_table[i];
 683             uint64_t offset = entry & BME_TABLE_ENTRY_OFFSET_MASK;
 684
 685             if (check_table_entry(entry, s->cluster_size) < 0) {
 686                 res->corruptions++;
 687                 continue;
 688             }
 689
 690             if (offset == 0) {
 691                 continue;
 692             }
 693
 694             ret = qcow2_inc_refcounts_imrt(bs, res,
 695                                            refcount_table, refcount_table_size,
 696                                            offset, s->cluster_size);
 697             if (ret < 0) {
 698                 g_free(bitmap_table);
 699                 goto out;
 700             }
 701         }
 702
 703         g_free(bitmap_table);
 704     }
 705
 706 out:
 707     bitmap_list_free(bm_list);
 708
 709     return ret;
 710 }
 711
 712 /* bitmap_list_store
 713  * Store bitmap list to qcow2 image as a bitmap directory.
 714  * Everything is checked.
 715  */
 716 static int bitmap_list_store(BlockDriverState *bs, Qcow2BitmapList *bm_list,
 717                              uint64_t *offset, uint64_t *size, bool in_place)
 718 {
 719     int ret;
 720     uint8_t *dir;
 721     int64_t dir_offset = 0;
 722     uint64_t dir_size = 0;
 723     Qcow2Bitmap *bm;
 724     Qcow2BitmapDirEntry *e;
 725
 726     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
 727         dir_size += calc_dir_entry_size(strlen(bm->name), 0);
 728     }
 729
 730     if (dir_size == 0 || dir_size > QCOW2_MAX_BITMAP_DIRECTORY_SIZE) {
 731         return -EINVAL;
 732     }
 733
 734     if (in_place) {
 735         if (*size != dir_size || *offset == 0) {
 736             return -EINVAL;
 737         }
 738
 739         dir_offset = *offset;
 740     }
 741
 742     dir = g_try_malloc(dir_size);
 743     if (dir == NULL) {
 744         return -ENOMEM;
 745     }
 746
 747     e = (Qcow2BitmapDirEntry *)dir;
 748     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
 749         e->bitmap_table_offset = bm->table.offset;
 750         e->bitmap_table_size = bm->table.size;
 751         e->flags = bm->flags;
 752         e->type = BT_DIRTY_TRACKING_BITMAP;
 753         e->granularity_bits = bm->granularity_bits;
 754         e->name_size = strlen(bm->name);
 755         e->extra_data_size = 0;
 756         memcpy(e + 1, bm->name, e->name_size);
 757
 758         if (check_dir_entry(bs, e) < 0) {
 759             ret = -EINVAL;
 760             goto fail;
 761         }
 762
 763         e = next_dir_entry(e);
 764     }
 765
 766     bitmap_directory_to_be(dir, dir_size);
 767
 768     if (!in_place) {
 769         dir_offset = qcow2_alloc_clusters(bs, dir_size);
 770         if (dir_offset < 0) {
 771             ret = dir_offset;
 772             goto fail;
 773         }
 774     }
 775
 776     /* Actually, even in in-place case ignoring QCOW2_OL_BITMAP_DIRECTORY is not
 777      * necessary, because we drop QCOW2_AUTOCLEAR_BITMAPS when updating bitmap
 778      * directory in-place (actually, turn-off the extension), which is checked
 779      * in qcow2_check_metadata_overlap() */
 780     ret = qcow2_pre_write_overlap_check(
 781             bs, in_place ? QCOW2_OL_BITMAP_DIRECTORY : 0, dir_offset, dir_size,
 782             false);
 783     if (ret < 0) {
 784         goto fail;
 785     }
 786
 787     ret = bdrv_pwrite(bs->file, dir_offset, dir, dir_size);
 788     if (ret < 0) {
 789         goto fail;
 790     }
 791
 792     g_free(dir);
 793
 794     if (!in_place) {
 795         *size = dir_size;
 796         *offset = dir_offset;
 797     }
 798
 799     return 0;
 800
 801 fail:
 802     g_free(dir);
 803
 804     if (!in_place && dir_offset > 0) {
 805         qcow2_free_clusters(bs, dir_offset, dir_size, QCOW2_DISCARD_OTHER);
 806     }
 807
 808     return ret;
 809 }
 810
 811 /*
 812  * Bitmap List end
 813  */
 814
 815 static int update_ext_header_and_dir_in_place(BlockDriverState *bs,
 816                                               Qcow2BitmapList *bm_list)
 817 {
 818     BDRVQcow2State *s = bs->opaque;
 819     int ret;
 820
 821     if (!(s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS) ||
 822         bm_list == NULL || QSIMPLEQ_EMPTY(bm_list) ||
 823         bitmap_list_count(bm_list) != s->nb_bitmaps)
 824     {
 825         return -EINVAL;
 826     }
 827
 828     s->autoclear_features &= ~(uint64_t)QCOW2_AUTOCLEAR_BITMAPS;
 829     ret = update_header_sync(bs);
 830     if (ret < 0) {
 831         /* Two variants are possible here:
 832          * 1. Autoclear flag is dropped, all bitmaps will be lost.
 833          * 2. Autoclear flag is not dropped, old state is left.
 834          */
 835         return ret;
 836     }
 837
 838     /* autoclear bit is not set, so we can safely update bitmap directory */
 839
 840     ret = bitmap_list_store(bs, bm_list, &s->bitmap_directory_offset,
 841                             &s->bitmap_directory_size, true);
 842     if (ret < 0) {
 843         /* autoclear bit is cleared, so all leaked clusters would be removed on
 844          * qemu-img check */
 845         return ret;
 846     }
 847
 848     ret = update_header_sync(bs);
 849     if (ret < 0) {
 850         /* autoclear bit is cleared, so all leaked clusters would be removed on
 851          * qemu-img check */
 852         return ret;
 853     }
 854
 855     s->autoclear_features |= QCOW2_AUTOCLEAR_BITMAPS;
 856     return update_header_sync(bs);
 857     /* If final update_header_sync() fails, two variants are possible:
 858      * 1. Autoclear flag is not set, all bitmaps will be lost.
 859      * 2. Autoclear flag is set, header and directory are successfully updated.
 860      */
 861 }
 862
 863 static int update_ext_header_and_dir(BlockDriverState *bs,
 864                                      Qcow2BitmapList *bm_list)
 865 {
 866     BDRVQcow2State *s = bs->opaque;
 867     int ret;
 868     uint64_t new_offset = 0;
 869     uint64_t new_size = 0;
 870     uint32_t new_nb_bitmaps = 0;
 871     uint64_t old_offset = s->bitmap_directory_offset;
 872     uint64_t old_size = s->bitmap_directory_size;
 873     uint32_t old_nb_bitmaps = s->nb_bitmaps;
 874     uint64_t old_autocl = s->autoclear_features;
 875
 876     if (bm_list != NULL && !QSIMPLEQ_EMPTY(bm_list)) {
 877         new_nb_bitmaps = bitmap_list_count(bm_list);
 878
 879         if (new_nb_bitmaps > QCOW2_MAX_BITMAPS) {
 880             return -EINVAL;
 881         }
 882
 883         ret = bitmap_list_store(bs, bm_list, &new_offset, &new_size, false);
 884         if (ret < 0) {
 885             return ret;
 886         }
 887
 888         ret = qcow2_flush_caches(bs);
 889         if (ret < 0) {
 890             goto fail;
 891         }
 892
 893         s->autoclear_features |= QCOW2_AUTOCLEAR_BITMAPS;
 894     } else {
 895         s->autoclear_features &= ~(uint64_t)QCOW2_AUTOCLEAR_BITMAPS;
 896     }
 897
 898     s->bitmap_directory_offset = new_offset;
 899     s->bitmap_directory_size = new_size;
 900     s->nb_bitmaps = new_nb_bitmaps;
 901
 902     ret = update_header_sync(bs);
 903     if (ret < 0) {
 904         goto fail;
 905     }
 906
 907     if (old_size > 0) {
 908         qcow2_free_clusters(bs, old_offset, old_size, QCOW2_DISCARD_OTHER);
 909     }
 910
 911     return 0;
 912
 913 fail:
 914     if (new_offset > 0) {
 915         qcow2_free_clusters(bs, new_offset, new_size, QCOW2_DISCARD_OTHER);
 916     }
 917
 918     s->bitmap_directory_offset = old_offset;
 919     s->bitmap_directory_size = old_size;
 920     s->nb_bitmaps = old_nb_bitmaps;
 921     s->autoclear_features = old_autocl;
 922
 923     return ret;
 924 }
 925
 926 /* for g_slist_foreach for GSList of BdrvDirtyBitmap* elements */
 927 static void release_dirty_bitmap_helper(gpointer bitmap,
 928                                         gpointer bs)
 929 {
 930     bdrv_release_dirty_bitmap(bs, bitmap);
 931 }
 932
 933 /* for g_slist_foreach for GSList of BdrvDirtyBitmap* elements */
 934 static void set_readonly_helper(gpointer bitmap, gpointer value)
 935 {
 936     bdrv_dirty_bitmap_set_readonly(bitmap, (bool)value);
 937 }
 938
 939 /* qcow2_load_dirty_bitmaps()
 940  * Return value is a hint for caller: true means that the Qcow2 header was
 941  * updated. (false doesn't mean that the header should be updated by the
 942  * caller, it just means that updating was not needed or the image cannot be
 943  * written to).
 944  * On failure the function returns false.
 945  */
 946 bool qcow2_load_dirty_bitmaps(BlockDriverState *bs, Error **errp)
 947 {
 948     BDRVQcow2State *s = bs->opaque;
 949     Qcow2BitmapList *bm_list;
 950     Qcow2Bitmap *bm;
 951     GSList *created_dirty_bitmaps = NULL;
 952     bool header_updated = false;
 953
 954     if (s->nb_bitmaps == 0) {
 955         /* No bitmaps - nothing to do */
 956         return false;
 957     }
 958
 959     bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
 960                                s->bitmap_directory_size, errp);
 961     if (bm_list == NULL) {
 962         return false;
 963     }
 964
 965     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
 966         if (!(bm->flags & BME_FLAG_IN_USE)) {
 967             BdrvDirtyBitmap *bitmap = load_bitmap(bs, bm, errp);
 968             if (bitmap == NULL) {
 969                 goto fail;
 970             }
 971
 972             if (!(bm->flags & BME_FLAG_AUTO)) {
 973                 bdrv_disable_dirty_bitmap(bitmap);
 974             }
 975             bdrv_dirty_bitmap_set_persistance(bitmap, true);
 976             bm->flags |= BME_FLAG_IN_USE;
 977             created_dirty_bitmaps =
 978                     g_slist_append(created_dirty_bitmaps, bitmap);
 979         }
 980     }
 981
 982     if (created_dirty_bitmaps != NULL) {
 983         if (can_write(bs)) {
 984             /* in_use flags must be updated */
 985             int ret = update_ext_header_and_dir_in_place(bs, bm_list);
 986             if (ret < 0) {
 987                 error_setg_errno(errp, -ret, "Can't update bitmap directory");
 988                 goto fail;
 989             }
 990             header_updated = true;
 991         } else {
 992             g_slist_foreach(created_dirty_bitmaps, set_readonly_helper,
 993                             (gpointer)true);
 994         }
 995     }
 996
 997     g_slist_free(created_dirty_bitmaps);
 998     bitmap_list_free(bm_list);
 999
1000     return header_updated;
1001
1002 fail:
1003     g_slist_foreach(created_dirty_bitmaps, release_dirty_bitmap_helper, bs);
1004     g_slist_free(created_dirty_bitmaps);
1005     bitmap_list_free(bm_list);
1006
1007     return false;
1008 }
1009
1010
1011 static Qcow2BitmapInfoFlagsList *get_bitmap_info_flags(uint32_t flags)
1012 {
1013     Qcow2BitmapInfoFlagsList *list = NULL;
1014     Qcow2BitmapInfoFlagsList **plist = &list;
1015     int i;
1016
1017     static const struct {
1018         int bme;  /* Bitmap directory entry flags */
1019         int info; /* The flags to report to the user */
1020     } map[] = {
1021         { BME_FLAG_IN_USE, QCOW2_BITMAP_INFO_FLAGS_IN_USE },
1022         { BME_FLAG_AUTO,   QCOW2_BITMAP_INFO_FLAGS_AUTO },
1023     };
1024
1025     int map_size = ARRAY_SIZE(map);
1026
1027     for (i = 0; i < map_size; ++i) {
1028         if (flags & map[i].bme) {
1029             Qcow2BitmapInfoFlagsList *entry =
1030                 g_new0(Qcow2BitmapInfoFlagsList, 1);
1031             entry->value = map[i].info;
1032             *plist = entry;
1033             plist = &entry->next;
1034             flags &= ~map[i].bme;
1035         }
1036     }
1037     /* Check if the BME_* mapping above is complete */
1038     assert(!flags);
1039
1040     return list;
1041 }
1042
1043 /*
1044  * qcow2_get_bitmap_info_list()
1045  * Returns a list of QCOW2 bitmap details.
1046  * In case of no bitmaps, the function returns NULL and
1047  * the @errp parameter is not set.
1048  * When bitmap information can not be obtained, the function returns
1049  * NULL and the @errp parameter is set.
1050  */
1051 Qcow2BitmapInfoList *qcow2_get_bitmap_info_list(BlockDriverState *bs,
1052                                                 Error **errp)
1053 {
1054     BDRVQcow2State *s = bs->opaque;
1055     Qcow2BitmapList *bm_list;
1056     Qcow2Bitmap *bm;
1057     Qcow2BitmapInfoList *list = NULL;
1058     Qcow2BitmapInfoList **plist = &list;
1059
1060     if (s->nb_bitmaps == 0) {
1061         return NULL;
1062     }
1063
1064     bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
1065                                s->bitmap_directory_size, errp);
1066     if (bm_list == NULL) {
1067         return NULL;
1068     }
1069
1070     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
1071         Qcow2BitmapInfo *info = g_new0(Qcow2BitmapInfo, 1);
1072         Qcow2BitmapInfoList *obj = g_new0(Qcow2BitmapInfoList, 1);
1073         info->granularity = 1U << bm->granularity_bits;
1074         info->name = g_strdup(bm->name);
1075         info->flags = get_bitmap_info_flags(bm->flags & ~BME_RESERVED_FLAGS);
1076         obj->value = info;
1077         *plist = obj;
1078         plist = &obj->next;
1079     }
1080
1081     bitmap_list_free(bm_list);
1082
1083     return list;
1084 }
1085
1086 int qcow2_reopen_bitmaps_rw_hint(BlockDriverState *bs, bool *header_updated,
1087                                  Error **errp)
1088 {
1089     BDRVQcow2State *s = bs->opaque;
1090     Qcow2BitmapList *bm_list;
1091     Qcow2Bitmap *bm;
1092     GSList *ro_dirty_bitmaps = NULL;
1093     int ret = 0;
1094
1095     if (header_updated != NULL) {
1096         *header_updated = false;
1097     }
1098
1099     if (s->nb_bitmaps == 0) {
1100         /* No bitmaps - nothing to do */
1101         return 0;
1102     }
1103
1104     if (!can_write(bs)) {
1105         error_setg(errp, "Can't write to the image on reopening bitmaps rw");
1106         return -EINVAL;
1107     }
1108
1109     bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
1110                                s->bitmap_directory_size, errp);
1111     if (bm_list == NULL) {
1112         return -EINVAL;
1113     }
1114
1115     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
1116         if (!(bm->flags & BME_FLAG_IN_USE)) {
1117             BdrvDirtyBitmap *bitmap = bdrv_find_dirty_bitmap(bs, bm->name);
1118             if (bitmap == NULL) {
1119                 continue;
1120             }
1121
1122             if (!bdrv_dirty_bitmap_readonly(bitmap)) {
1123                 error_setg(errp, "Bitmap %s is not readonly but not marked"
1124                                  "'IN_USE' in the image. Something went wrong,"
1125                                  "all the bitmaps may be corrupted", bm->name);
1126                 ret = -EINVAL;
1127                 goto out;
1128             }
1129
1130             bm->flags |= BME_FLAG_IN_USE;
1131             ro_dirty_bitmaps = g_slist_append(ro_dirty_bitmaps, bitmap);
1132         }
1133     }
1134
1135     if (ro_dirty_bitmaps != NULL) {
1136         /* in_use flags must be updated */
1137         ret = update_ext_header_and_dir_in_place(bs, bm_list);
1138         if (ret < 0) {
1139             error_setg_errno(errp, -ret, "Can't update bitmap directory");
1140             goto out;
1141         }
1142         if (header_updated != NULL) {
1143             *header_updated = true;
1144         }
1145         g_slist_foreach(ro_dirty_bitmaps, set_readonly_helper, false);
1146     }
1147
1148 out:
1149     g_slist_free(ro_dirty_bitmaps);
1150     bitmap_list_free(bm_list);
1151
1152     return ret;
1153 }
1154
1155 int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
1156 {
1157     return qcow2_reopen_bitmaps_rw_hint(bs, NULL, errp);
1158 }
1159
1160 /* store_bitmap_data()
1161  * Store bitmap to image, filling bitmap table accordingly.
1162  */
1163 static uint64_t *store_bitmap_data(BlockDriverState *bs,
1164                                    BdrvDirtyBitmap *bitmap,
1165                                    uint32_t *bitmap_table_size, Error **errp)
1166 {
1167     int ret;
1168     BDRVQcow2State *s = bs->opaque;
1169     int64_t offset;
1170     uint64_t limit;
1171     uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
1172     const char *bm_name = bdrv_dirty_bitmap_name(bitmap);
1173     uint8_t *buf = NULL;
1174     BdrvDirtyBitmapIter *dbi;
1175     uint64_t *tb;
1176     uint64_t tb_size =
1177             size_to_clusters(s,
1178                 bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size));
1179
1180     if (tb_size > BME_MAX_TABLE_SIZE ||
1181         tb_size * s->cluster_size > BME_MAX_PHYS_SIZE)
1182     {
1183         error_setg(errp, "Bitmap '%s' is too big", bm_name);
1184         return NULL;
1185     }
1186
1187     tb = g_try_new0(uint64_t, tb_size);
1188     if (tb == NULL) {
1189         error_setg(errp, "No memory");
1190         return NULL;
1191     }
1192
1193     dbi = bdrv_dirty_iter_new(bitmap);
1194     buf = g_malloc(s->cluster_size);
1195     limit = bytes_covered_by_bitmap_cluster(s, bitmap);
1196     assert(DIV_ROUND_UP(bm_size, limit) == tb_size);
1197
1198     while ((offset = bdrv_dirty_iter_next(dbi)) >= 0) {
1199         uint64_t cluster = offset / limit;
1200         uint64_t end, write_size;
1201         int64_t off;
1202
1203         /*
1204          * We found the first dirty offset, but want to write out the
1205          * entire cluster of the bitmap that includes that offset,
1206          * including any leading zero bits.
1207          */
1208         offset = QEMU_ALIGN_DOWN(offset, limit);
1209         end = MIN(bm_size, offset + limit);
1210         write_size = bdrv_dirty_bitmap_serialization_size(bitmap, offset,
1211                                                           end - offset);
1212         assert(write_size <= s->cluster_size);
1213
1214         off = qcow2_alloc_clusters(bs, s->cluster_size);
1215         if (off < 0) {
1216             error_setg_errno(errp, -off,
1217                              "Failed to allocate clusters for bitmap '%s'",
1218                              bm_name);
1219             goto fail;
1220         }
1221         tb[cluster] = off;
1222
1223         bdrv_dirty_bitmap_serialize_part(bitmap, buf, offset, end - offset);
1224         if (write_size < s->cluster_size) {
1225             memset(buf + write_size, 0, s->cluster_size - write_size);
1226         }
1227
1228         ret = qcow2_pre_write_overlap_check(bs, 0, off, s->cluster_size, false);
1229         if (ret < 0) {
1230             error_setg_errno(errp, -ret, "Qcow2 overlap check failed");
1231             goto fail;
1232         }
1233
1234         ret = bdrv_pwrite(bs->file, off, buf, s->cluster_size);
1235         if (ret < 0) {
1236             error_setg_errno(errp, -ret, "Failed to write bitmap '%s' to file",
1237                              bm_name);
1238             goto fail;
1239         }
1240
1241         if (end >= bm_size) {
1242             break;
1243         }
1244
1245         bdrv_set_dirty_iter(dbi, end);
1246     }
1247
1248     *bitmap_table_size = tb_size;
1249     g_free(buf);
1250     bdrv_dirty_iter_free(dbi);
1251
1252     return tb;
1253
1254 fail:
1255     clear_bitmap_table(bs, tb, tb_size);
1256     g_free(buf);
1257     bdrv_dirty_iter_free(dbi);
1258     g_free(tb);
1259
1260     return NULL;
1261 }
1262
1263 /* store_bitmap()
1264  * Store bm->dirty_bitmap to qcow2.
1265  * Set bm->table_offset and bm->table_size accordingly.
1266  */
1267 static int store_bitmap(BlockDriverState *bs, Qcow2Bitmap *bm, Error **errp)
1268 {
1269     int ret;
1270     uint64_t *tb;
1271     int64_t tb_offset;
1272     uint32_t tb_size;
1273     BdrvDirtyBitmap *bitmap = bm->dirty_bitmap;
1274     const char *bm_name;
1275
1276     assert(bitmap != NULL);
1277
1278     bm_name = bdrv_dirty_bitmap_name(bitmap);
1279
1280     tb = store_bitmap_data(bs, bitmap, &tb_size, errp);
1281     if (tb == NULL) {
1282         return -EINVAL;
1283     }
1284
1285     assert(tb_size <= BME_MAX_TABLE_SIZE);
1286     tb_offset = qcow2_alloc_clusters(bs, tb_size * sizeof(tb[0]));
1287     if (tb_offset < 0) {
1288         error_setg_errno(errp, -tb_offset,
1289                          "Failed to allocate clusters for bitmap '%s'",
1290                          bm_name);
1291         ret = tb_offset;
1292         goto fail;
1293     }
1294
1295     ret = qcow2_pre_write_overlap_check(bs, 0, tb_offset,
1296                                         tb_size * sizeof(tb[0]), false);
1297     if (ret < 0) {
1298         error_setg_errno(errp, -ret, "Qcow2 overlap check failed");
1299         goto fail;
1300     }
1301
1302     bitmap_table_to_be(tb, tb_size);
1303     ret = bdrv_pwrite(bs->file, tb_offset, tb, tb_size * sizeof(tb[0]));
1304     if (ret < 0) {
1305         error_setg_errno(errp, -ret, "Failed to write bitmap '%s' to file",
1306                          bm_name);
1307         goto fail;
1308     }
1309
1310     g_free(tb);
1311
1312     bm->table.offset = tb_offset;
1313     bm->table.size = tb_size;
1314
1315     return 0;
1316
1317 fail:
1318     clear_bitmap_table(bs, tb, tb_size);
1319
1320     if (tb_offset > 0) {
1321         qcow2_free_clusters(bs, tb_offset, tb_size * sizeof(tb[0]),
1322                             QCOW2_DISCARD_OTHER);
1323     }
1324
1325     g_free(tb);
1326
1327     return ret;
1328 }
1329
1330 static Qcow2Bitmap *find_bitmap_by_name(Qcow2BitmapList *bm_list,
1331                                         const char *name)
1332 {
1333     Qcow2Bitmap *bm;
1334
1335     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
1336         if (strcmp(name, bm->name) == 0) {
1337             return bm;
1338         }
1339     }
1340
1341     return NULL;
1342 }
1343
1344 void qcow2_remove_persistent_dirty_bitmap(BlockDriverState *bs,
1345                                           const char *name,
1346                                           Error **errp)
1347 {
1348     int ret;
1349     BDRVQcow2State *s = bs->opaque;
1350     Qcow2Bitmap *bm;
1351     Qcow2BitmapList *bm_list;
1352
1353     if (s->nb_bitmaps == 0) {
1354         /* Absence of the bitmap is not an error: see explanation above
1355          * bdrv_remove_persistent_dirty_bitmap() definition. */
1356         return;
1357     }
1358
1359     bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
1360                                s->bitmap_directory_size, errp);
1361     if (bm_list == NULL) {
1362         return;
1363     }
1364
1365     bm = find_bitmap_by_name(bm_list, name);
1366     if (bm == NULL) {
1367         goto fail;
1368     }
1369
1370     QSIMPLEQ_REMOVE(bm_list, bm, Qcow2Bitmap, entry);
1371
1372     ret = update_ext_header_and_dir(bs, bm_list);
1373     if (ret < 0) {
1374         error_setg_errno(errp, -ret, "Failed to update bitmap extension");
1375         goto fail;
1376     }
1377
1378     free_bitmap_clusters(bs, &bm->table);
1379
1380 fail:
1381     bitmap_free(bm);
1382     bitmap_list_free(bm_list);
1383 }
1384
1385 void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp)
1386 {
1387     BdrvDirtyBitmap *bitmap;
1388     BDRVQcow2State *s = bs->opaque;
1389     uint32_t new_nb_bitmaps = s->nb_bitmaps;
1390     uint64_t new_dir_size = s->bitmap_directory_size;
1391     int ret;
1392     Qcow2BitmapList *bm_list;
1393     Qcow2Bitmap *bm;
1394     QSIMPLEQ_HEAD(, Qcow2BitmapTable) drop_tables;
1395     Qcow2BitmapTable *tb, *tb_next;
1396
1397     if (!bdrv_has_changed_persistent_bitmaps(bs)) {
1398         /* nothing to do */
1399         return;
1400     }
1401
1402     if (!can_write(bs)) {
1403         error_setg(errp, "No write access");
1404         return;
1405     }
1406
1407     QSIMPLEQ_INIT(&drop_tables);
1408
1409     if (s->nb_bitmaps == 0) {
1410         bm_list = bitmap_list_new();
1411     } else {
1412         bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
1413                                    s->bitmap_directory_size, errp);
1414         if (bm_list == NULL) {
1415             return;
1416         }
1417     }
1418
1419     /* check constraints and names */
1420     for (bitmap = bdrv_dirty_bitmap_next(bs, NULL); bitmap != NULL;
1421          bitmap = bdrv_dirty_bitmap_next(bs, bitmap))
1422     {
1423         const char *name = bdrv_dirty_bitmap_name(bitmap);
1424         uint32_t granularity = bdrv_dirty_bitmap_granularity(bitmap);
1425         Qcow2Bitmap *bm;
1426
1427         if (!bdrv_dirty_bitmap_get_persistance(bitmap) ||
1428             bdrv_dirty_bitmap_readonly(bitmap))
1429         {
1430             continue;
1431         }
1432
1433         if (check_constraints_on_bitmap(bs, name, granularity, errp) < 0) {
1434             error_prepend(errp, "Bitmap '%s' doesn't satisfy the constraints: ",
1435                           name);
1436             goto fail;
1437         }
1438
1439         bm = find_bitmap_by_name(bm_list, name);
1440         if (bm == NULL) {
1441             if (++new_nb_bitmaps > QCOW2_MAX_BITMAPS) {
1442                 error_setg(errp, "Too many persistent bitmaps");
1443                 goto fail;
1444             }
1445
1446             new_dir_size += calc_dir_entry_size(strlen(name), 0);
1447             if (new_dir_size > QCOW2_MAX_BITMAP_DIRECTORY_SIZE) {
1448                 error_setg(errp, "Bitmap directory is too large");
1449                 goto fail;
1450             }
1451
1452             bm = g_new0(Qcow2Bitmap, 1);
1453             bm->name = g_strdup(name);
1454             QSIMPLEQ_INSERT_TAIL(bm_list, bm, entry);
1455         } else {
1456             if (!(bm->flags & BME_FLAG_IN_USE)) {
1457                 error_setg(errp, "Bitmap '%s' already exists in the image",
1458                            name);
1459                 goto fail;
1460             }
1461             tb = g_memdup(&bm->table, sizeof(bm->table));
1462             bm->table.offset = 0;
1463             bm->table.size = 0;
1464             QSIMPLEQ_INSERT_TAIL(&drop_tables, tb, entry);
1465         }
1466         bm->flags = bdrv_dirty_bitmap_enabled(bitmap) ? BME_FLAG_AUTO : 0;
1467         bm->granularity_bits = ctz32(bdrv_dirty_bitmap_granularity(bitmap));
1468         bm->dirty_bitmap = bitmap;
1469     }
1470
1471     /* allocate clusters and store bitmaps */
1472     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
1473         if (bm->dirty_bitmap == NULL) {
1474             continue;
1475         }
1476
1477         ret = store_bitmap(bs, bm, errp);
1478         if (ret < 0) {
1479             goto fail;
1480         }
1481     }
1482
1483     ret = update_ext_header_and_dir(bs, bm_list);
1484     if (ret < 0) {
1485         error_setg_errno(errp, -ret, "Failed to update bitmap extension");
1486         goto fail;
1487     }
1488
1489     /* Bitmap directory was successfully updated, so, old data can be dropped.
1490      * TODO it is better to reuse these clusters */
1491     QSIMPLEQ_FOREACH_SAFE(tb, &drop_tables, entry, tb_next) {
1492         free_bitmap_clusters(bs, tb);
1493         g_free(tb);
1494     }
1495
1496     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
1497         /* For safety, we remove bitmap after storing.
1498          * We may be here in two cases:
1499          * 1. bdrv_close. It's ok to drop bitmap.
1500          * 2. inactivation. It means migration without 'dirty-bitmaps'
1501          *    capability, so bitmaps are not marked with
1502          *    BdrvDirtyBitmap.migration flags. It's not bad to drop them too,
1503          *    and reload on invalidation.
1504          */
1505         if (bm->dirty_bitmap == NULL) {
1506             continue;
1507         }
1508
1509         bdrv_release_dirty_bitmap(bs, bm->dirty_bitmap);
1510     }
1511
1512     bitmap_list_free(bm_list);
1513     return;
1514
1515 fail:
1516     QSIMPLEQ_FOREACH(bm, bm_list, entry) {
1517         if (bm->dirty_bitmap == NULL || bm->table.offset == 0) {
1518             continue;
1519         }
1520
1521         free_bitmap_clusters(bs, &bm->table);
1522     }
1523
1524     QSIMPLEQ_FOREACH_SAFE(tb, &drop_tables, entry, tb_next) {
1525         g_free(tb);
1526     }
1527
1528     bitmap_list_free(bm_list);
1529 }
1530
1531 int qcow2_reopen_bitmaps_ro(BlockDriverState *bs, Error **errp)
1532 {
1533     BdrvDirtyBitmap *bitmap;
1534     Error *local_err = NULL;
1535
1536     qcow2_store_persistent_dirty_bitmaps(bs, &local_err);
1537     if (local_err != NULL) {
1538         error_propagate(errp, local_err);
1539         return -EINVAL;
1540     }
1541
1542     for (bitmap = bdrv_dirty_bitmap_next(bs, NULL); bitmap != NULL;
1543          bitmap = bdrv_dirty_bitmap_next(bs, bitmap))
1544     {
1545         if (bdrv_dirty_bitmap_get_persistance(bitmap)) {
1546             bdrv_dirty_bitmap_set_readonly(bitmap, true);
1547         }
1548     }
1549
1550     return 0;
1551 }
1552
1553 bool qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs,
1554                                       const char *name,
1555                                       uint32_t granularity,
1556                                       Error **errp)
1557 {
1558     BDRVQcow2State *s = bs->opaque;
1559     bool found;
1560     Qcow2BitmapList *bm_list;
1561
1562     if (s->qcow_version < 3) {
1563         /* Without autoclear_features, we would always have to assume
1564          * that a program without persistent dirty bitmap support has
1565          * accessed this qcow2 file when opening it, and would thus
1566          * have to drop all dirty bitmaps (defeating their purpose).
1567          */
1568         error_setg(errp, "Cannot store dirty bitmaps in qcow2 v2 files");
1569         goto fail;
1570     }
1571
1572     if (check_constraints_on_bitmap(bs, name, granularity, errp) != 0) {
1573         goto fail;
1574     }
1575
1576     if (s->nb_bitmaps == 0) {
1577         return true;
1578     }
1579
1580     if (s->nb_bitmaps >= QCOW2_MAX_BITMAPS) {
1581         error_setg(errp,
1582                    "Maximum number of persistent bitmaps is already reached");
1583         goto fail;
1584     }
1585
1586     if (s->bitmap_directory_size + calc_dir_entry_size(strlen(name), 0) >
1587         QCOW2_MAX_BITMAP_DIRECTORY_SIZE)
1588     {
1589         error_setg(errp, "Not enough space in the bitmap directory");
1590         goto fail;
1591     }
1592
1593     bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
1594                                s->bitmap_directory_size, errp);
1595     if (bm_list == NULL) {
1596         goto fail;
1597     }
1598
1599     found = find_bitmap_by_name(bm_list, name);
1600     bitmap_list_free(bm_list);
1601     if (found) {
1602         error_setg(errp, "Bitmap with the same name is already stored");
1603         goto fail;
1604     }
1605
1606     return true;
1607
1608 fail:
1609     error_prepend(errp, "Can't make bitmap '%s' persistent in '%s': ",
1610                   name, bdrv_get_device_or_node_name(bs));
1611     return false;
1612 }