block/dirty-bitmap.c

   1 /*
   2  * Block Dirty Bitmap
   3  *
   4  * Copyright (c) 2016-2017 Red Hat. Inc
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #include "qemu/osdep.h"
  25 #include "qapi/error.h"
  26 #include "trace.h"
  27 #include "block/block_int.h"
  28 #include "block/blockjob.h"
  29 #include "qemu/main-loop.h"
  30
  31 struct BdrvDirtyBitmap {
  32     BlockDriverState *bs;
  33     HBitmap *bitmap;            /* Dirty bitmap implementation */
  34     bool busy;                  /* Bitmap is busy, it can't be used via QMP */
  35     BdrvDirtyBitmap *successor; /* Anonymous child, if any. */
  36     char *name;                 /* Optional non-empty unique ID */
  37     int64_t size;               /* Size of the bitmap, in bytes */
  38     bool disabled;              /* Bitmap is disabled. It ignores all writes to
  39                                    the device */
  40     int active_iterators;       /* How many iterators are active */
  41     bool readonly;              /* Bitmap is read-only. This field also
  42                                    prevents the respective image from being
  43                                    modified (i.e. blocks writes and discards).
  44                                    Such operations must fail and both the image
  45                                    and this bitmap must remain unchanged while
  46                                    this flag is set. */
  47     bool persistent;            /* bitmap must be saved to owner disk image */
  48     bool inconsistent;          /* bitmap is persistent, but inconsistent.
  49                                    It cannot be used at all in any way, except
  50                                    a QMP user can remove it. */
  51     bool skip_store;            /* We are either migrating or deleting this
  52                                  * bitmap; it should not be stored on the next
  53                                  * inactivation. */
  54     QLIST_ENTRY(BdrvDirtyBitmap) list;
  55 };
  56
  57 struct BdrvDirtyBitmapIter {
  58     HBitmapIter hbi;
  59     BdrvDirtyBitmap *bitmap;
  60 };
  61
  62 static inline void bdrv_dirty_bitmaps_lock(BlockDriverState *bs)
  63 {
  64     qemu_mutex_lock(&bs->dirty_bitmap_mutex);
  65 }
  66
  67 static inline void bdrv_dirty_bitmaps_unlock(BlockDriverState *bs)
  68 {
  69     qemu_mutex_unlock(&bs->dirty_bitmap_mutex);
  70 }
  71
  72 void bdrv_dirty_bitmap_lock(BdrvDirtyBitmap *bitmap)
  73 {
  74     bdrv_dirty_bitmaps_lock(bitmap->bs);
  75 }
  76
  77 void bdrv_dirty_bitmap_unlock(BdrvDirtyBitmap *bitmap)
  78 {
  79     bdrv_dirty_bitmaps_unlock(bitmap->bs);
  80 }
  81
  82 /* Called with BQL or dirty_bitmap lock taken.  */
  83 BdrvDirtyBitmap *bdrv_find_dirty_bitmap(BlockDriverState *bs, const char *name)
  84 {
  85     BdrvDirtyBitmap *bm;
  86
  87     assert(name);
  88     QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) {
  89         if (bm->name && !strcmp(name, bm->name)) {
  90             return bm;
  91         }
  92     }
  93     return NULL;
  94 }
  95
  96 /* Called with BQL taken.  */
  97 BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
  98                                           uint32_t granularity,
  99                                           const char *name,
 100                                           Error **errp)
 101 {
 102     int64_t bitmap_size;
 103     BdrvDirtyBitmap *bitmap;
 104
 105     assert(is_power_of_2(granularity) && granularity >= BDRV_SECTOR_SIZE);
 106
 107     if (name) {
 108         if (bdrv_find_dirty_bitmap(bs, name)) {
 109             error_setg(errp, "Bitmap already exists: %s", name);
 110             return NULL;
 111         }
 112         if (strlen(name) > BDRV_BITMAP_MAX_NAME_SIZE) {
 113             error_setg(errp, "Bitmap name too long: %s", name);
 114             return NULL;
 115         }
 116     }
 117     bitmap_size = bdrv_getlength(bs);
 118     if (bitmap_size < 0) {
 119         error_setg_errno(errp, -bitmap_size, "could not get length of device");
 120         errno = -bitmap_size;
 121         return NULL;
 122     }
 123     bitmap = g_new0(BdrvDirtyBitmap, 1);
 124     bitmap->bs = bs;
 125     bitmap->bitmap = hbitmap_alloc(bitmap_size, ctz32(granularity));
 126     bitmap->size = bitmap_size;
 127     bitmap->name = g_strdup(name);
 128     bitmap->disabled = false;
 129     bdrv_dirty_bitmaps_lock(bs);
 130     QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list);
 131     bdrv_dirty_bitmaps_unlock(bs);
 132     return bitmap;
 133 }
 134
 135 int64_t bdrv_dirty_bitmap_size(const BdrvDirtyBitmap *bitmap)
 136 {
 137     return bitmap->size;
 138 }
 139
 140 const char *bdrv_dirty_bitmap_name(const BdrvDirtyBitmap *bitmap)
 141 {
 142     return bitmap->name;
 143 }
 144
 145 /* Called with BQL taken.  */
 146 bool bdrv_dirty_bitmap_has_successor(BdrvDirtyBitmap *bitmap)
 147 {
 148     return bitmap->successor;
 149 }
 150
 151 static bool bdrv_dirty_bitmap_busy(const BdrvDirtyBitmap *bitmap)
 152 {
 153     return bitmap->busy;
 154 }
 155
 156 void bdrv_dirty_bitmap_set_busy(BdrvDirtyBitmap *bitmap, bool busy)
 157 {
 158     bdrv_dirty_bitmaps_lock(bitmap->bs);
 159     bitmap->busy = busy;
 160     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 161 }
 162
 163 /* Called with BQL taken.  */
 164 bool bdrv_dirty_bitmap_enabled(BdrvDirtyBitmap *bitmap)
 165 {
 166     return !bitmap->disabled;
 167 }
 168
 169 /* Called with BQL taken.  */
 170 static bool bdrv_dirty_bitmap_recording(BdrvDirtyBitmap *bitmap)
 171 {
 172     return !bitmap->disabled || (bitmap->successor &&
 173                                  !bitmap->successor->disabled);
 174 }
 175
 176 int bdrv_dirty_bitmap_check(const BdrvDirtyBitmap *bitmap, uint32_t flags,
 177                             Error **errp)
 178 {
 179     if ((flags & BDRV_BITMAP_BUSY) && bdrv_dirty_bitmap_busy(bitmap)) {
 180         error_setg(errp, "Bitmap '%s' is currently in use by another"
 181                    " operation and cannot be used", bitmap->name);
 182         return -1;
 183     }
 184
 185     if ((flags & BDRV_BITMAP_RO) && bdrv_dirty_bitmap_readonly(bitmap)) {
 186         error_setg(errp, "Bitmap '%s' is readonly and cannot be modified",
 187                    bitmap->name);
 188         return -1;
 189     }
 190
 191     if ((flags & BDRV_BITMAP_INCONSISTENT) &&
 192         bdrv_dirty_bitmap_inconsistent(bitmap)) {
 193         error_setg(errp, "Bitmap '%s' is inconsistent and cannot be used",
 194                    bitmap->name);
 195         error_append_hint(errp, "Try block-dirty-bitmap-remove to delete"
 196                           " this bitmap from disk\n");
 197         return -1;
 198     }
 199
 200     return 0;
 201 }
 202
 203 /**
 204  * Create a successor bitmap destined to replace this bitmap after an operation.
 205  * Requires that the bitmap is not marked busy and has no successor.
 206  * The successor will be enabled if the parent bitmap was.
 207  * Called with BQL taken.
 208  */
 209 int bdrv_dirty_bitmap_create_successor(BdrvDirtyBitmap *bitmap, Error **errp)
 210 {
 211     uint64_t granularity;
 212     BdrvDirtyBitmap *child;
 213
 214     if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_BUSY, errp)) {
 215         return -1;
 216     }
 217     if (bdrv_dirty_bitmap_has_successor(bitmap)) {
 218         error_setg(errp, "Cannot create a successor for a bitmap that already "
 219                    "has one");
 220         return -1;
 221     }
 222
 223     /* Create an anonymous successor */
 224     granularity = bdrv_dirty_bitmap_granularity(bitmap);
 225     child = bdrv_create_dirty_bitmap(bitmap->bs, granularity, NULL, errp);
 226     if (!child) {
 227         return -1;
 228     }
 229
 230     /* Successor will be on or off based on our current state. */
 231     child->disabled = bitmap->disabled;
 232     bitmap->disabled = true;
 233
 234     /* Install the successor and mark the parent as busy */
 235     bitmap->successor = child;
 236     bitmap->busy = true;
 237     return 0;
 238 }
 239
 240 void bdrv_enable_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap)
 241 {
 242     bitmap->disabled = false;
 243 }
 244
 245 /* Called with BQL taken. */
 246 void bdrv_dirty_bitmap_enable_successor(BdrvDirtyBitmap *bitmap)
 247 {
 248     assert(bitmap->bs == bitmap->successor->bs);
 249     bdrv_dirty_bitmaps_lock(bitmap->bs);
 250     bdrv_enable_dirty_bitmap_locked(bitmap->successor);
 251     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 252 }
 253
 254 /* Called within bdrv_dirty_bitmap_lock..unlock and with BQL taken.  */
 255 static void bdrv_release_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap)
 256 {
 257     assert(!bitmap->active_iterators);
 258     assert(!bdrv_dirty_bitmap_busy(bitmap));
 259     assert(!bdrv_dirty_bitmap_has_successor(bitmap));
 260     QLIST_REMOVE(bitmap, list);
 261     hbitmap_free(bitmap->bitmap);
 262     g_free(bitmap->name);
 263     g_free(bitmap);
 264 }
 265
 266 /**
 267  * For a bitmap with a successor, yield our name to the successor,
 268  * delete the old bitmap, and return a handle to the new bitmap.
 269  * Called with BQL taken.
 270  */
 271 BdrvDirtyBitmap *bdrv_dirty_bitmap_abdicate(BdrvDirtyBitmap *bitmap,
 272                                             Error **errp)
 273 {
 274     char *name;
 275     BdrvDirtyBitmap *successor = bitmap->successor;
 276
 277     if (successor == NULL) {
 278         error_setg(errp, "Cannot relinquish control if "
 279                    "there's no successor present");
 280         return NULL;
 281     }
 282
 283     name = bitmap->name;
 284     bitmap->name = NULL;
 285     successor->name = name;
 286     bitmap->successor = NULL;
 287     successor->persistent = bitmap->persistent;
 288     bitmap->persistent = false;
 289     bitmap->busy = false;
 290     bdrv_release_dirty_bitmap(bitmap);
 291
 292     return successor;
 293 }
 294
 295 /**
 296  * In cases of failure where we can no longer safely delete the parent,
 297  * we may wish to re-join the parent and child/successor.
 298  * The merged parent will be marked as not busy.
 299  * The marged parent will be enabled if and only if the successor was enabled.
 300  * Called within bdrv_dirty_bitmap_lock..unlock and with BQL taken.
 301  */
 302 BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap_locked(BdrvDirtyBitmap *parent,
 303                                                   Error **errp)
 304 {
 305     BdrvDirtyBitmap *successor = parent->successor;
 306
 307     if (!successor) {
 308         error_setg(errp, "Cannot reclaim a successor when none is present");
 309         return NULL;
 310     }
 311
 312     hbitmap_merge(parent->bitmap, successor->bitmap, parent->bitmap);
 313
 314     parent->disabled = successor->disabled;
 315     parent->busy = false;
 316     bdrv_release_dirty_bitmap_locked(successor);
 317     parent->successor = NULL;
 318
 319     return parent;
 320 }
 321
 322 /* Called with BQL taken. */
 323 BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap(BdrvDirtyBitmap *parent,
 324                                            Error **errp)
 325 {
 326     BdrvDirtyBitmap *ret;
 327
 328     bdrv_dirty_bitmaps_lock(parent->bs);
 329     ret = bdrv_reclaim_dirty_bitmap_locked(parent, errp);
 330     bdrv_dirty_bitmaps_unlock(parent->bs);
 331
 332     return ret;
 333 }
 334
 335 /**
 336  * Truncates _all_ bitmaps attached to a BDS.
 337  * Called with BQL taken.
 338  */
 339 void bdrv_dirty_bitmap_truncate(BlockDriverState *bs, int64_t bytes)
 340 {
 341     BdrvDirtyBitmap *bitmap;
 342
 343     bdrv_dirty_bitmaps_lock(bs);
 344     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
 345         assert(!bdrv_dirty_bitmap_busy(bitmap));
 346         assert(!bdrv_dirty_bitmap_has_successor(bitmap));
 347         assert(!bitmap->active_iterators);
 348         hbitmap_truncate(bitmap->bitmap, bytes);
 349         bitmap->size = bytes;
 350     }
 351     bdrv_dirty_bitmaps_unlock(bs);
 352 }
 353
 354 /* Called with BQL taken.  */
 355 void bdrv_release_dirty_bitmap(BdrvDirtyBitmap *bitmap)
 356 {
 357     BlockDriverState *bs = bitmap->bs;
 358
 359     bdrv_dirty_bitmaps_lock(bs);
 360     bdrv_release_dirty_bitmap_locked(bitmap);
 361     bdrv_dirty_bitmaps_unlock(bs);
 362 }
 363
 364 /**
 365  * Release all named dirty bitmaps attached to a BDS (for use in bdrv_close()).
 366  * There must not be any busy bitmaps attached.
 367  * This function does not remove persistent bitmaps from the storage.
 368  * Called with BQL taken.
 369  */
 370 void bdrv_release_named_dirty_bitmaps(BlockDriverState *bs)
 371 {
 372     BdrvDirtyBitmap *bm, *next;
 373
 374     bdrv_dirty_bitmaps_lock(bs);
 375     QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) {
 376         if (bdrv_dirty_bitmap_name(bm)) {
 377             bdrv_release_dirty_bitmap_locked(bm);
 378         }
 379     }
 380     bdrv_dirty_bitmaps_unlock(bs);
 381 }
 382
 383 /**
 384  * Remove persistent dirty bitmap from the storage if it exists.
 385  * Absence of bitmap is not an error, because we have the following scenario:
 386  * BdrvDirtyBitmap can have .persistent = true but not yet saved and have no
 387  * stored version. For such bitmap bdrv_remove_persistent_dirty_bitmap() should
 388  * not fail.
 389  * This function doesn't release corresponding BdrvDirtyBitmap.
 390  */
 391 static int coroutine_fn
 392 bdrv_co_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name,
 393                                        Error **errp)
 394 {
 395     if (bs->drv && bs->drv->bdrv_co_remove_persistent_dirty_bitmap) {
 396         return bs->drv->bdrv_co_remove_persistent_dirty_bitmap(bs, name, errp);
 397     }
 398
 399     return 0;
 400 }
 401
 402 typedef struct BdrvRemovePersistentDirtyBitmapCo {
 403     BlockDriverState *bs;
 404     const char *name;
 405     Error **errp;
 406     int ret;
 407 } BdrvRemovePersistentDirtyBitmapCo;
 408
 409 static void coroutine_fn
 410 bdrv_co_remove_persistent_dirty_bitmap_entry(void *opaque)
 411 {
 412     BdrvRemovePersistentDirtyBitmapCo *s = opaque;
 413
 414     s->ret = bdrv_co_remove_persistent_dirty_bitmap(s->bs, s->name, s->errp);
 415     aio_wait_kick();
 416 }
 417
 418 int bdrv_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name,
 419                                         Error **errp)
 420 {
 421     if (qemu_in_coroutine()) {
 422         return bdrv_co_remove_persistent_dirty_bitmap(bs, name, errp);
 423     } else {
 424         Coroutine *co;
 425         BdrvRemovePersistentDirtyBitmapCo s = {
 426             .bs = bs,
 427             .name = name,
 428             .errp = errp,
 429             .ret = -EINPROGRESS,
 430         };
 431
 432         co = qemu_coroutine_create(bdrv_co_remove_persistent_dirty_bitmap_entry,
 433                                    &s);
 434         bdrv_coroutine_enter(bs, co);
 435         BDRV_POLL_WHILE(bs, s.ret == -EINPROGRESS);
 436
 437         return s.ret;
 438     }
 439 }
 440
 441 bool
 442 bdrv_supports_persistent_dirty_bitmap(BlockDriverState *bs)
 443 {
 444     if (bs->drv && bs->drv->bdrv_supports_persistent_dirty_bitmap) {
 445         return bs->drv->bdrv_supports_persistent_dirty_bitmap(bs);
 446     }
 447     return false;
 448 }
 449
 450 static bool coroutine_fn
 451 bdrv_co_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
 452                                    uint32_t granularity, Error **errp)
 453 {
 454     BlockDriver *drv = bs->drv;
 455
 456     if (!drv) {
 457         error_setg_errno(errp, ENOMEDIUM,
 458                          "Can't store persistent bitmaps to %s",
 459                          bdrv_get_device_or_node_name(bs));
 460         return false;
 461     }
 462
 463     if (!drv->bdrv_co_can_store_new_dirty_bitmap) {
 464         error_setg_errno(errp, ENOTSUP,
 465                          "Can't store persistent bitmaps to %s",
 466                          bdrv_get_device_or_node_name(bs));
 467         return false;
 468     }
 469
 470     return drv->bdrv_co_can_store_new_dirty_bitmap(bs, name, granularity, errp);
 471 }
 472
 473 typedef struct BdrvCanStoreNewDirtyBitmapCo {
 474     BlockDriverState *bs;
 475     const char *name;
 476     uint32_t granularity;
 477     Error **errp;
 478     bool ret;
 479
 480     bool in_progress;
 481 } BdrvCanStoreNewDirtyBitmapCo;
 482
 483 static void coroutine_fn bdrv_co_can_store_new_dirty_bitmap_entry(void *opaque)
 484 {
 485     BdrvCanStoreNewDirtyBitmapCo *s = opaque;
 486
 487     s->ret = bdrv_co_can_store_new_dirty_bitmap(s->bs, s->name, s->granularity,
 488                                                 s->errp);
 489     s->in_progress = false;
 490     aio_wait_kick();
 491 }
 492
 493 bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
 494                                      uint32_t granularity, Error **errp)
 495 {
 496     IO_CODE();
 497     if (qemu_in_coroutine()) {
 498         return bdrv_co_can_store_new_dirty_bitmap(bs, name, granularity, errp);
 499     } else {
 500         Coroutine *co;
 501         BdrvCanStoreNewDirtyBitmapCo s = {
 502             .bs = bs,
 503             .name = name,
 504             .granularity = granularity,
 505             .errp = errp,
 506             .in_progress = true,
 507         };
 508
 509         co = qemu_coroutine_create(bdrv_co_can_store_new_dirty_bitmap_entry,
 510                                    &s);
 511         bdrv_coroutine_enter(bs, co);
 512         BDRV_POLL_WHILE(bs, s.in_progress);
 513
 514         return s.ret;
 515     }
 516 }
 517
 518 void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
 519 {
 520     bdrv_dirty_bitmaps_lock(bitmap->bs);
 521     bitmap->disabled = true;
 522     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 523 }
 524
 525 void bdrv_enable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
 526 {
 527     bdrv_dirty_bitmaps_lock(bitmap->bs);
 528     bdrv_enable_dirty_bitmap_locked(bitmap);
 529     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 530 }
 531
 532 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
 533 {
 534     BdrvDirtyBitmap *bm;
 535     BlockDirtyInfoList *list = NULL;
 536     BlockDirtyInfoList **tail = &list;
 537
 538     bdrv_dirty_bitmaps_lock(bs);
 539     QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) {
 540         BlockDirtyInfo *info = g_new0(BlockDirtyInfo, 1);
 541
 542         info->count = bdrv_get_dirty_count(bm);
 543         info->granularity = bdrv_dirty_bitmap_granularity(bm);
 544         info->has_name = !!bm->name;
 545         info->name = g_strdup(bm->name);
 546         info->recording = bdrv_dirty_bitmap_recording(bm);
 547         info->busy = bdrv_dirty_bitmap_busy(bm);
 548         info->persistent = bm->persistent;
 549         info->has_inconsistent = bm->inconsistent;
 550         info->inconsistent = bm->inconsistent;
 551         QAPI_LIST_APPEND(tail, info);
 552     }
 553     bdrv_dirty_bitmaps_unlock(bs);
 554
 555     return list;
 556 }
 557
 558 /* Called within bdrv_dirty_bitmap_lock..unlock */
 559 bool bdrv_dirty_bitmap_get_locked(BdrvDirtyBitmap *bitmap, int64_t offset)
 560 {
 561     return hbitmap_get(bitmap->bitmap, offset);
 562 }
 563
 564 bool bdrv_dirty_bitmap_get(BdrvDirtyBitmap *bitmap, int64_t offset)
 565 {
 566     bool ret;
 567     bdrv_dirty_bitmaps_lock(bitmap->bs);
 568     ret = bdrv_dirty_bitmap_get_locked(bitmap, offset);
 569     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 570
 571     return ret;
 572 }
 573
 574 /**
 575  * Chooses a default granularity based on the existing cluster size,
 576  * but clamped between [4K, 64K]. Defaults to 64K in the case that there
 577  * is no cluster size information available.
 578  */
 579 uint32_t bdrv_get_default_bitmap_granularity(BlockDriverState *bs)
 580 {
 581     BlockDriverInfo bdi;
 582     uint32_t granularity;
 583
 584     if (bdrv_get_info(bs, &bdi) >= 0 && bdi.cluster_size > 0) {
 585         granularity = MAX(4096, bdi.cluster_size);
 586         granularity = MIN(65536, granularity);
 587     } else {
 588         granularity = 65536;
 589     }
 590
 591     return granularity;
 592 }
 593
 594 uint32_t bdrv_dirty_bitmap_granularity(const BdrvDirtyBitmap *bitmap)
 595 {
 596     return 1U << hbitmap_granularity(bitmap->bitmap);
 597 }
 598
 599 BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap)
 600 {
 601     BdrvDirtyBitmapIter *iter = g_new(BdrvDirtyBitmapIter, 1);
 602     hbitmap_iter_init(&iter->hbi, bitmap->bitmap, 0);
 603     iter->bitmap = bitmap;
 604     bitmap->active_iterators++;
 605     return iter;
 606 }
 607
 608 void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter)
 609 {
 610     if (!iter) {
 611         return;
 612     }
 613     assert(iter->bitmap->active_iterators > 0);
 614     iter->bitmap->active_iterators--;
 615     g_free(iter);
 616 }
 617
 618 int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)
 619 {
 620     return hbitmap_iter_next(&iter->hbi);
 621 }
 622
 623 /* Called within bdrv_dirty_bitmap_lock..unlock */
 624 void bdrv_set_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,
 625                                   int64_t offset, int64_t bytes)
 626 {
 627     assert(!bdrv_dirty_bitmap_readonly(bitmap));
 628     hbitmap_set(bitmap->bitmap, offset, bytes);
 629 }
 630
 631 void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
 632                            int64_t offset, int64_t bytes)
 633 {
 634     bdrv_dirty_bitmaps_lock(bitmap->bs);
 635     bdrv_set_dirty_bitmap_locked(bitmap, offset, bytes);
 636     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 637 }
 638
 639 /* Called within bdrv_dirty_bitmap_lock..unlock */
 640 void bdrv_reset_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,
 641                                     int64_t offset, int64_t bytes)
 642 {
 643     assert(!bdrv_dirty_bitmap_readonly(bitmap));
 644     hbitmap_reset(bitmap->bitmap, offset, bytes);
 645 }
 646
 647 void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
 648                              int64_t offset, int64_t bytes)
 649 {
 650     bdrv_dirty_bitmaps_lock(bitmap->bs);
 651     bdrv_reset_dirty_bitmap_locked(bitmap, offset, bytes);
 652     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 653 }
 654
 655 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out)
 656 {
 657     IO_CODE();
 658     assert(!bdrv_dirty_bitmap_readonly(bitmap));
 659     bdrv_dirty_bitmaps_lock(bitmap->bs);
 660     if (!out) {
 661         hbitmap_reset_all(bitmap->bitmap);
 662     } else {
 663         HBitmap *backup = bitmap->bitmap;
 664         bitmap->bitmap = hbitmap_alloc(bitmap->size,
 665                                        hbitmap_granularity(backup));
 666         *out = backup;
 667     }
 668     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 669 }
 670
 671 void bdrv_restore_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *backup)
 672 {
 673     HBitmap *tmp = bitmap->bitmap;
 674     assert(!bdrv_dirty_bitmap_readonly(bitmap));
 675     GLOBAL_STATE_CODE();
 676     bitmap->bitmap = backup;
 677     hbitmap_free(tmp);
 678 }
 679
 680 uint64_t bdrv_dirty_bitmap_serialization_size(const BdrvDirtyBitmap *bitmap,
 681                                               uint64_t offset, uint64_t bytes)
 682 {
 683     return hbitmap_serialization_size(bitmap->bitmap, offset, bytes);
 684 }
 685
 686 uint64_t bdrv_dirty_bitmap_serialization_align(const BdrvDirtyBitmap *bitmap)
 687 {
 688     return hbitmap_serialization_align(bitmap->bitmap);
 689 }
 690
 691 /* Return the disk size covered by a chunk of serialized bitmap data. */
 692 uint64_t bdrv_dirty_bitmap_serialization_coverage(int serialized_chunk_size,
 693                                                   const BdrvDirtyBitmap *bitmap)
 694 {
 695     uint64_t granularity = bdrv_dirty_bitmap_granularity(bitmap);
 696     uint64_t limit = granularity * (serialized_chunk_size << 3);
 697
 698     assert(QEMU_IS_ALIGNED(limit,
 699                            bdrv_dirty_bitmap_serialization_align(bitmap)));
 700     return limit;
 701 }
 702
 703
 704 void bdrv_dirty_bitmap_serialize_part(const BdrvDirtyBitmap *bitmap,
 705                                       uint8_t *buf, uint64_t offset,
 706                                       uint64_t bytes)
 707 {
 708     hbitmap_serialize_part(bitmap->bitmap, buf, offset, bytes);
 709 }
 710
 711 void bdrv_dirty_bitmap_deserialize_part(BdrvDirtyBitmap *bitmap,
 712                                         uint8_t *buf, uint64_t offset,
 713                                         uint64_t bytes, bool finish)
 714 {
 715     hbitmap_deserialize_part(bitmap->bitmap, buf, offset, bytes, finish);
 716 }
 717
 718 void bdrv_dirty_bitmap_deserialize_zeroes(BdrvDirtyBitmap *bitmap,
 719                                           uint64_t offset, uint64_t bytes,
 720                                           bool finish)
 721 {
 722     hbitmap_deserialize_zeroes(bitmap->bitmap, offset, bytes, finish);
 723 }
 724
 725 void bdrv_dirty_bitmap_deserialize_ones(BdrvDirtyBitmap *bitmap,
 726                                         uint64_t offset, uint64_t bytes,
 727                                         bool finish)
 728 {
 729     hbitmap_deserialize_ones(bitmap->bitmap, offset, bytes, finish);
 730 }
 731
 732 void bdrv_dirty_bitmap_deserialize_finish(BdrvDirtyBitmap *bitmap)
 733 {
 734     hbitmap_deserialize_finish(bitmap->bitmap);
 735 }
 736
 737 void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes)
 738 {
 739     BdrvDirtyBitmap *bitmap;
 740     IO_CODE();
 741
 742     if (QLIST_EMPTY(&bs->dirty_bitmaps)) {
 743         return;
 744     }
 745
 746     bdrv_dirty_bitmaps_lock(bs);
 747     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
 748         if (!bdrv_dirty_bitmap_enabled(bitmap)) {
 749             continue;
 750         }
 751         assert(!bdrv_dirty_bitmap_readonly(bitmap));
 752         hbitmap_set(bitmap->bitmap, offset, bytes);
 753     }
 754     bdrv_dirty_bitmaps_unlock(bs);
 755 }
 756
 757 /**
 758  * Advance a BdrvDirtyBitmapIter to an arbitrary offset.
 759  */
 760 void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *iter, int64_t offset)
 761 {
 762     hbitmap_iter_init(&iter->hbi, iter->hbi.hb, offset);
 763 }
 764
 765 int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap)
 766 {
 767     return hbitmap_count(bitmap->bitmap);
 768 }
 769
 770 bool bdrv_dirty_bitmap_readonly(const BdrvDirtyBitmap *bitmap)
 771 {
 772     return bitmap->readonly;
 773 }
 774
 775 /* Called with BQL taken. */
 776 void bdrv_dirty_bitmap_set_readonly(BdrvDirtyBitmap *bitmap, bool value)
 777 {
 778     bdrv_dirty_bitmaps_lock(bitmap->bs);
 779     bitmap->readonly = value;
 780     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 781 }
 782
 783 bool bdrv_has_readonly_bitmaps(BlockDriverState *bs)
 784 {
 785     BdrvDirtyBitmap *bm;
 786     QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) {
 787         if (bm->readonly) {
 788             return true;
 789         }
 790     }
 791
 792     return false;
 793 }
 794
 795 bool bdrv_has_named_bitmaps(BlockDriverState *bs)
 796 {
 797     BdrvDirtyBitmap *bm;
 798
 799     QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) {
 800         if (bdrv_dirty_bitmap_name(bm)) {
 801             return true;
 802         }
 803     }
 804
 805     return false;
 806 }
 807
 808 /* Called with BQL taken. */
 809 void bdrv_dirty_bitmap_set_persistence(BdrvDirtyBitmap *bitmap, bool persistent)
 810 {
 811     bdrv_dirty_bitmaps_lock(bitmap->bs);
 812     bitmap->persistent = persistent;
 813     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 814 }
 815
 816 /* Called with BQL taken. */
 817 void bdrv_dirty_bitmap_set_inconsistent(BdrvDirtyBitmap *bitmap)
 818 {
 819     bdrv_dirty_bitmaps_lock(bitmap->bs);
 820     assert(bitmap->persistent == true);
 821     bitmap->inconsistent = true;
 822     bitmap->disabled = true;
 823     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 824 }
 825
 826 /* Called with BQL taken. */
 827 void bdrv_dirty_bitmap_skip_store(BdrvDirtyBitmap *bitmap, bool skip)
 828 {
 829     bdrv_dirty_bitmaps_lock(bitmap->bs);
 830     bitmap->skip_store = skip;
 831     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 832 }
 833
 834 bool bdrv_dirty_bitmap_get_persistence(BdrvDirtyBitmap *bitmap)
 835 {
 836     return bitmap->persistent && !bitmap->skip_store;
 837 }
 838
 839 bool bdrv_dirty_bitmap_inconsistent(const BdrvDirtyBitmap *bitmap)
 840 {
 841     return bitmap->inconsistent;
 842 }
 843
 844 BdrvDirtyBitmap *bdrv_dirty_bitmap_first(BlockDriverState *bs)
 845 {
 846     return QLIST_FIRST(&bs->dirty_bitmaps);
 847 }
 848
 849 BdrvDirtyBitmap *bdrv_dirty_bitmap_next(BdrvDirtyBitmap *bitmap)
 850 {
 851     return QLIST_NEXT(bitmap, list);
 852 }
 853
 854 char *bdrv_dirty_bitmap_sha256(const BdrvDirtyBitmap *bitmap, Error **errp)
 855 {
 856     return hbitmap_sha256(bitmap->bitmap, errp);
 857 }
 858
 859 int64_t bdrv_dirty_bitmap_next_dirty(BdrvDirtyBitmap *bitmap, int64_t offset,
 860                                      int64_t bytes)
 861 {
 862     return hbitmap_next_dirty(bitmap->bitmap, offset, bytes);
 863 }
 864
 865 int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, int64_t offset,
 866                                     int64_t bytes)
 867 {
 868     return hbitmap_next_zero(bitmap->bitmap, offset, bytes);
 869 }
 870
 871 bool bdrv_dirty_bitmap_next_dirty_area(BdrvDirtyBitmap *bitmap,
 872         int64_t start, int64_t end, int64_t max_dirty_count,
 873         int64_t *dirty_start, int64_t *dirty_count)
 874 {
 875     return hbitmap_next_dirty_area(bitmap->bitmap, start, end, max_dirty_count,
 876                                    dirty_start, dirty_count);
 877 }
 878
 879 bool bdrv_dirty_bitmap_status(BdrvDirtyBitmap *bitmap, int64_t offset,
 880                               int64_t bytes, int64_t *count)
 881 {
 882     return hbitmap_status(bitmap->bitmap, offset, bytes, count);
 883 }
 884
 885 /**
 886  * bdrv_merge_dirty_bitmap: merge src into dest.
 887  * Ensures permissions on bitmaps are reasonable; use for public API.
 888  *
 889  * @backup: If provided, make a copy of dest here prior to merge.
 890  *
 891  * Returns true on success, false on failure. In case of failure bitmaps are
 892  * untouched.
 893  */
 894 bool bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src,
 895                              HBitmap **backup, Error **errp)
 896 {
 897     bool ret = false;
 898
 899     bdrv_dirty_bitmaps_lock(dest->bs);
 900     if (src->bs != dest->bs) {
 901         bdrv_dirty_bitmaps_lock(src->bs);
 902     }
 903
 904     if (bdrv_dirty_bitmap_check(dest, BDRV_BITMAP_DEFAULT, errp)) {
 905         goto out;
 906     }
 907
 908     if (bdrv_dirty_bitmap_check(src, BDRV_BITMAP_ALLOW_RO, errp)) {
 909         goto out;
 910     }
 911
 912     if (bdrv_dirty_bitmap_size(src) != bdrv_dirty_bitmap_size(dest)) {
 913         error_setg(errp, "Bitmaps are of different sizes (destination size is %"
 914                    PRId64 ", source size is %" PRId64 ") and can't be merged",
 915                    bdrv_dirty_bitmap_size(dest), bdrv_dirty_bitmap_size(src));
 916         goto out;
 917     }
 918
 919     bdrv_dirty_bitmap_merge_internal(dest, src, backup, false);
 920     ret = true;
 921
 922 out:
 923     bdrv_dirty_bitmaps_unlock(dest->bs);
 924     if (src->bs != dest->bs) {
 925         bdrv_dirty_bitmaps_unlock(src->bs);
 926     }
 927
 928     return ret;
 929 }
 930
 931 /**
 932  * bdrv_dirty_bitmap_merge_internal: merge src into dest.
 933  * Does NOT check bitmap permissions; not suitable for use as public API.
 934  * @dest, @src and @backup (if not NULL) must have same size.
 935  *
 936  * @backup: If provided, make a copy of dest here prior to merge.
 937  * @lock: If true, lock and unlock bitmaps on the way in/out.
 938  */
 939 void bdrv_dirty_bitmap_merge_internal(BdrvDirtyBitmap *dest,
 940                                       const BdrvDirtyBitmap *src,
 941                                       HBitmap **backup,
 942                                       bool lock)
 943 {
 944     IO_CODE();
 945
 946     assert(!bdrv_dirty_bitmap_readonly(dest));
 947     assert(!bdrv_dirty_bitmap_inconsistent(dest));
 948     assert(!bdrv_dirty_bitmap_inconsistent(src));
 949
 950     if (lock) {
 951         bdrv_dirty_bitmaps_lock(dest->bs);
 952         if (src->bs != dest->bs) {
 953             bdrv_dirty_bitmaps_lock(src->bs);
 954         }
 955     }
 956
 957     if (backup) {
 958         *backup = dest->bitmap;
 959         dest->bitmap = hbitmap_alloc(dest->size, hbitmap_granularity(*backup));
 960         hbitmap_merge(*backup, src->bitmap, dest->bitmap);
 961     } else {
 962         hbitmap_merge(dest->bitmap, src->bitmap, dest->bitmap);
 963     }
 964
 965     if (lock) {
 966         bdrv_dirty_bitmaps_unlock(dest->bs);
 967         if (src->bs != dest->bs) {
 968             bdrv_dirty_bitmaps_unlock(src->bs);
 969         }
 970     }
 971 }