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 /**
 170  * bdrv_dirty_bitmap_status: This API is now deprecated.
 171  * Called with BQL taken.
 172  *
 173  * A BdrvDirtyBitmap can be in four possible user-visible states:
 174  * (1) Active:   successor is NULL, and disabled is false: full r/w mode
 175  * (2) Disabled: successor is NULL, and disabled is true: qualified r/w mode,
 176  *               guest writes are dropped, but monitor writes are possible,
 177  *               through commands like merge and clear.
 178  * (3) Frozen:   successor is not NULL.
 179  *               A frozen bitmap cannot be renamed, deleted, cleared, set,
 180  *               enabled, merged to, etc. A frozen bitmap can only abdicate()
 181  *               or reclaim().
 182  *               In this state, the anonymous successor bitmap may be either
 183  *               Active and recording writes from the guest (e.g. backup jobs),
 184  *               or it can be Disabled and not recording writes.
 185  * (4) Locked:   Whether Active or Disabled, the user cannot modify this bitmap
 186  *               in any way from the monitor.
 187  * (5) Inconsistent: This is a persistent bitmap whose "in use" bit is set, and
 188  *                   is unusable by QEMU. It can be deleted to remove it from
 189  *                   the qcow2.
 190  */
 191 DirtyBitmapStatus bdrv_dirty_bitmap_status(BdrvDirtyBitmap *bitmap)
 192 {
 193     if (bdrv_dirty_bitmap_inconsistent(bitmap)) {
 194         return DIRTY_BITMAP_STATUS_INCONSISTENT;
 195     } else if (bdrv_dirty_bitmap_has_successor(bitmap)) {
 196         return DIRTY_BITMAP_STATUS_FROZEN;
 197     } else if (bdrv_dirty_bitmap_busy(bitmap)) {
 198         return DIRTY_BITMAP_STATUS_LOCKED;
 199     } else if (!bdrv_dirty_bitmap_enabled(bitmap)) {
 200         return DIRTY_BITMAP_STATUS_DISABLED;
 201     } else {
 202         return DIRTY_BITMAP_STATUS_ACTIVE;
 203     }
 204 }
 205
 206 /* Called with BQL taken.  */
 207 static bool bdrv_dirty_bitmap_recording(BdrvDirtyBitmap *bitmap)
 208 {
 209     return !bitmap->disabled || (bitmap->successor &&
 210                                  !bitmap->successor->disabled);
 211 }
 212
 213 int bdrv_dirty_bitmap_check(const BdrvDirtyBitmap *bitmap, uint32_t flags,
 214                             Error **errp)
 215 {
 216     if ((flags & BDRV_BITMAP_BUSY) && bdrv_dirty_bitmap_busy(bitmap)) {
 217         error_setg(errp, "Bitmap '%s' is currently in use by another"
 218                    " operation and cannot be used", bitmap->name);
 219         return -1;
 220     }
 221
 222     if ((flags & BDRV_BITMAP_RO) && bdrv_dirty_bitmap_readonly(bitmap)) {
 223         error_setg(errp, "Bitmap '%s' is readonly and cannot be modified",
 224                    bitmap->name);
 225         return -1;
 226     }
 227
 228     if ((flags & BDRV_BITMAP_INCONSISTENT) &&
 229         bdrv_dirty_bitmap_inconsistent(bitmap)) {
 230         error_setg(errp, "Bitmap '%s' is inconsistent and cannot be used",
 231                    bitmap->name);
 232         error_append_hint(errp, "Try block-dirty-bitmap-remove to delete"
 233                           " this bitmap from disk");
 234         return -1;
 235     }
 236
 237     return 0;
 238 }
 239
 240 /**
 241  * Create a successor bitmap destined to replace this bitmap after an operation.
 242  * Requires that the bitmap is not marked busy and has no successor.
 243  * The successor will be enabled if the parent bitmap was.
 244  * Called with BQL taken.
 245  */
 246 int bdrv_dirty_bitmap_create_successor(BdrvDirtyBitmap *bitmap, Error **errp)
 247 {
 248     uint64_t granularity;
 249     BdrvDirtyBitmap *child;
 250
 251     if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_BUSY, errp)) {
 252         return -1;
 253     }
 254     if (bdrv_dirty_bitmap_has_successor(bitmap)) {
 255         error_setg(errp, "Cannot create a successor for a bitmap that already "
 256                    "has one");
 257         return -1;
 258     }
 259
 260     /* Create an anonymous successor */
 261     granularity = bdrv_dirty_bitmap_granularity(bitmap);
 262     child = bdrv_create_dirty_bitmap(bitmap->bs, granularity, NULL, errp);
 263     if (!child) {
 264         return -1;
 265     }
 266
 267     /* Successor will be on or off based on our current state. */
 268     child->disabled = bitmap->disabled;
 269     bitmap->disabled = true;
 270
 271     /* Install the successor and mark the parent as busy */
 272     bitmap->successor = child;
 273     bitmap->busy = true;
 274     return 0;
 275 }
 276
 277 void bdrv_enable_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap)
 278 {
 279     bitmap->disabled = false;
 280 }
 281
 282 /* Called with BQL taken. */
 283 void bdrv_dirty_bitmap_enable_successor(BdrvDirtyBitmap *bitmap)
 284 {
 285     assert(bitmap->bs == bitmap->successor->bs);
 286     bdrv_dirty_bitmaps_lock(bitmap->bs);
 287     bdrv_enable_dirty_bitmap_locked(bitmap->successor);
 288     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 289 }
 290
 291 /* Called within bdrv_dirty_bitmap_lock..unlock and with BQL taken.  */
 292 static void bdrv_release_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap)
 293 {
 294     assert(!bitmap->active_iterators);
 295     assert(!bdrv_dirty_bitmap_busy(bitmap));
 296     assert(!bdrv_dirty_bitmap_has_successor(bitmap));
 297     QLIST_REMOVE(bitmap, list);
 298     hbitmap_free(bitmap->bitmap);
 299     g_free(bitmap->name);
 300     g_free(bitmap);
 301 }
 302
 303 /**
 304  * For a bitmap with a successor, yield our name to the successor,
 305  * delete the old bitmap, and return a handle to the new bitmap.
 306  * Called with BQL taken.
 307  */
 308 BdrvDirtyBitmap *bdrv_dirty_bitmap_abdicate(BdrvDirtyBitmap *bitmap,
 309                                             Error **errp)
 310 {
 311     char *name;
 312     BdrvDirtyBitmap *successor = bitmap->successor;
 313
 314     if (successor == NULL) {
 315         error_setg(errp, "Cannot relinquish control if "
 316                    "there's no successor present");
 317         return NULL;
 318     }
 319
 320     name = bitmap->name;
 321     bitmap->name = NULL;
 322     successor->name = name;
 323     bitmap->successor = NULL;
 324     successor->persistent = bitmap->persistent;
 325     bitmap->persistent = false;
 326     bitmap->busy = false;
 327     bdrv_release_dirty_bitmap(bitmap);
 328
 329     return successor;
 330 }
 331
 332 /**
 333  * In cases of failure where we can no longer safely delete the parent,
 334  * we may wish to re-join the parent and child/successor.
 335  * The merged parent will be marked as not busy.
 336  * The marged parent will be enabled if and only if the successor was enabled.
 337  * Called within bdrv_dirty_bitmap_lock..unlock and with BQL taken.
 338  */
 339 BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap_locked(BdrvDirtyBitmap *parent,
 340                                                   Error **errp)
 341 {
 342     BdrvDirtyBitmap *successor = parent->successor;
 343
 344     if (!successor) {
 345         error_setg(errp, "Cannot reclaim a successor when none is present");
 346         return NULL;
 347     }
 348
 349     if (!hbitmap_merge(parent->bitmap, successor->bitmap, parent->bitmap)) {
 350         error_setg(errp, "Merging of parent and successor bitmap failed");
 351         return NULL;
 352     }
 353
 354     parent->disabled = successor->disabled;
 355     parent->busy = false;
 356     bdrv_release_dirty_bitmap_locked(successor);
 357     parent->successor = NULL;
 358
 359     return parent;
 360 }
 361
 362 /* Called with BQL taken. */
 363 BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap(BdrvDirtyBitmap *parent,
 364                                            Error **errp)
 365 {
 366     BdrvDirtyBitmap *ret;
 367
 368     bdrv_dirty_bitmaps_lock(parent->bs);
 369     ret = bdrv_reclaim_dirty_bitmap_locked(parent, errp);
 370     bdrv_dirty_bitmaps_unlock(parent->bs);
 371
 372     return ret;
 373 }
 374
 375 /**
 376  * Truncates _all_ bitmaps attached to a BDS.
 377  * Called with BQL taken.
 378  */
 379 void bdrv_dirty_bitmap_truncate(BlockDriverState *bs, int64_t bytes)
 380 {
 381     BdrvDirtyBitmap *bitmap;
 382
 383     bdrv_dirty_bitmaps_lock(bs);
 384     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
 385         assert(!bdrv_dirty_bitmap_busy(bitmap));
 386         assert(!bdrv_dirty_bitmap_has_successor(bitmap));
 387         assert(!bitmap->active_iterators);
 388         hbitmap_truncate(bitmap->bitmap, bytes);
 389         bitmap->size = bytes;
 390     }
 391     bdrv_dirty_bitmaps_unlock(bs);
 392 }
 393
 394 /* Called with BQL taken.  */
 395 void bdrv_release_dirty_bitmap(BdrvDirtyBitmap *bitmap)
 396 {
 397     BlockDriverState *bs = bitmap->bs;
 398
 399     bdrv_dirty_bitmaps_lock(bs);
 400     bdrv_release_dirty_bitmap_locked(bitmap);
 401     bdrv_dirty_bitmaps_unlock(bs);
 402 }
 403
 404 /**
 405  * Release all named dirty bitmaps attached to a BDS (for use in bdrv_close()).
 406  * There must not be any busy bitmaps attached.
 407  * This function does not remove persistent bitmaps from the storage.
 408  * Called with BQL taken.
 409  */
 410 void bdrv_release_named_dirty_bitmaps(BlockDriverState *bs)
 411 {
 412     BdrvDirtyBitmap *bm, *next;
 413
 414     bdrv_dirty_bitmaps_lock(bs);
 415     QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) {
 416         if (bdrv_dirty_bitmap_name(bm)) {
 417             bdrv_release_dirty_bitmap_locked(bm);
 418         }
 419     }
 420     bdrv_dirty_bitmaps_unlock(bs);
 421 }
 422
 423 /**
 424  * Remove persistent dirty bitmap from the storage if it exists.
 425  * Absence of bitmap is not an error, because we have the following scenario:
 426  * BdrvDirtyBitmap can have .persistent = true but not yet saved and have no
 427  * stored version. For such bitmap bdrv_remove_persistent_dirty_bitmap() should
 428  * not fail.
 429  * This function doesn't release corresponding BdrvDirtyBitmap.
 430  */
 431 static int coroutine_fn
 432 bdrv_co_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name,
 433                                        Error **errp)
 434 {
 435     if (bs->drv && bs->drv->bdrv_co_remove_persistent_dirty_bitmap) {
 436         return bs->drv->bdrv_co_remove_persistent_dirty_bitmap(bs, name, errp);
 437     }
 438
 439     return 0;
 440 }
 441
 442 typedef struct BdrvRemovePersistentDirtyBitmapCo {
 443     BlockDriverState *bs;
 444     const char *name;
 445     Error **errp;
 446     int ret;
 447 } BdrvRemovePersistentDirtyBitmapCo;
 448
 449 static void coroutine_fn
 450 bdrv_co_remove_persistent_dirty_bitmap_entry(void *opaque)
 451 {
 452     BdrvRemovePersistentDirtyBitmapCo *s = opaque;
 453
 454     s->ret = bdrv_co_remove_persistent_dirty_bitmap(s->bs, s->name, s->errp);
 455     aio_wait_kick();
 456 }
 457
 458 int bdrv_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name,
 459                                         Error **errp)
 460 {
 461     if (qemu_in_coroutine()) {
 462         return bdrv_co_remove_persistent_dirty_bitmap(bs, name, errp);
 463     } else {
 464         Coroutine *co;
 465         BdrvRemovePersistentDirtyBitmapCo s = {
 466             .bs = bs,
 467             .name = name,
 468             .errp = errp,
 469             .ret = -EINPROGRESS,
 470         };
 471
 472         co = qemu_coroutine_create(bdrv_co_remove_persistent_dirty_bitmap_entry,
 473                                    &s);
 474         bdrv_coroutine_enter(bs, co);
 475         BDRV_POLL_WHILE(bs, s.ret == -EINPROGRESS);
 476
 477         return s.ret;
 478     }
 479 }
 480
 481 static bool coroutine_fn
 482 bdrv_co_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
 483                                    uint32_t granularity, Error **errp)
 484 {
 485     BlockDriver *drv = bs->drv;
 486
 487     if (!drv) {
 488         error_setg_errno(errp, ENOMEDIUM,
 489                          "Can't store persistent bitmaps to %s",
 490                          bdrv_get_device_or_node_name(bs));
 491         return false;
 492     }
 493
 494     if (!drv->bdrv_co_can_store_new_dirty_bitmap) {
 495         error_setg_errno(errp, ENOTSUP,
 496                          "Can't store persistent bitmaps to %s",
 497                          bdrv_get_device_or_node_name(bs));
 498         return false;
 499     }
 500
 501     return drv->bdrv_co_can_store_new_dirty_bitmap(bs, name, granularity, errp);
 502 }
 503
 504 typedef struct BdrvCanStoreNewDirtyBitmapCo {
 505     BlockDriverState *bs;
 506     const char *name;
 507     uint32_t granularity;
 508     Error **errp;
 509     bool ret;
 510
 511     bool in_progress;
 512 } BdrvCanStoreNewDirtyBitmapCo;
 513
 514 static void coroutine_fn bdrv_co_can_store_new_dirty_bitmap_entry(void *opaque)
 515 {
 516     BdrvCanStoreNewDirtyBitmapCo *s = opaque;
 517
 518     s->ret = bdrv_co_can_store_new_dirty_bitmap(s->bs, s->name, s->granularity,
 519                                                 s->errp);
 520     s->in_progress = false;
 521     aio_wait_kick();
 522 }
 523
 524 bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
 525                                      uint32_t granularity, Error **errp)
 526 {
 527     if (qemu_in_coroutine()) {
 528         return bdrv_co_can_store_new_dirty_bitmap(bs, name, granularity, errp);
 529     } else {
 530         Coroutine *co;
 531         BdrvCanStoreNewDirtyBitmapCo s = {
 532             .bs = bs,
 533             .name = name,
 534             .granularity = granularity,
 535             .errp = errp,
 536             .in_progress = true,
 537         };
 538
 539         co = qemu_coroutine_create(bdrv_co_can_store_new_dirty_bitmap_entry,
 540                                    &s);
 541         bdrv_coroutine_enter(bs, co);
 542         BDRV_POLL_WHILE(bs, s.in_progress);
 543
 544         return s.ret;
 545     }
 546 }
 547
 548 void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
 549 {
 550     bdrv_dirty_bitmaps_lock(bitmap->bs);
 551     bitmap->disabled = true;
 552     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 553 }
 554
 555 void bdrv_enable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
 556 {
 557     bdrv_dirty_bitmaps_lock(bitmap->bs);
 558     bdrv_enable_dirty_bitmap_locked(bitmap);
 559     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 560 }
 561
 562 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
 563 {
 564     BdrvDirtyBitmap *bm;
 565     BlockDirtyInfoList *list = NULL;
 566     BlockDirtyInfoList **plist = &list;
 567
 568     bdrv_dirty_bitmaps_lock(bs);
 569     QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) {
 570         BlockDirtyInfo *info = g_new0(BlockDirtyInfo, 1);
 571         BlockDirtyInfoList *entry = g_new0(BlockDirtyInfoList, 1);
 572         info->count = bdrv_get_dirty_count(bm);
 573         info->granularity = bdrv_dirty_bitmap_granularity(bm);
 574         info->has_name = !!bm->name;
 575         info->name = g_strdup(bm->name);
 576         info->status = bdrv_dirty_bitmap_status(bm);
 577         info->recording = bdrv_dirty_bitmap_recording(bm);
 578         info->busy = bdrv_dirty_bitmap_busy(bm);
 579         info->persistent = bm->persistent;
 580         info->has_inconsistent = bm->inconsistent;
 581         info->inconsistent = bm->inconsistent;
 582         entry->value = info;
 583         *plist = entry;
 584         plist = &entry->next;
 585     }
 586     bdrv_dirty_bitmaps_unlock(bs);
 587
 588     return list;
 589 }
 590
 591 /* Called within bdrv_dirty_bitmap_lock..unlock */
 592 bool bdrv_dirty_bitmap_get_locked(BdrvDirtyBitmap *bitmap, int64_t offset)
 593 {
 594     return hbitmap_get(bitmap->bitmap, offset);
 595 }
 596
 597 bool bdrv_dirty_bitmap_get(BdrvDirtyBitmap *bitmap, int64_t offset)
 598 {
 599     bool ret;
 600     bdrv_dirty_bitmaps_lock(bitmap->bs);
 601     ret = bdrv_dirty_bitmap_get_locked(bitmap, offset);
 602     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 603
 604     return ret;
 605 }
 606
 607 /**
 608  * Chooses a default granularity based on the existing cluster size,
 609  * but clamped between [4K, 64K]. Defaults to 64K in the case that there
 610  * is no cluster size information available.
 611  */
 612 uint32_t bdrv_get_default_bitmap_granularity(BlockDriverState *bs)
 613 {
 614     BlockDriverInfo bdi;
 615     uint32_t granularity;
 616
 617     if (bdrv_get_info(bs, &bdi) >= 0 && bdi.cluster_size > 0) {
 618         granularity = MAX(4096, bdi.cluster_size);
 619         granularity = MIN(65536, granularity);
 620     } else {
 621         granularity = 65536;
 622     }
 623
 624     return granularity;
 625 }
 626
 627 uint32_t bdrv_dirty_bitmap_granularity(const BdrvDirtyBitmap *bitmap)
 628 {
 629     return 1U << hbitmap_granularity(bitmap->bitmap);
 630 }
 631
 632 BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap)
 633 {
 634     BdrvDirtyBitmapIter *iter = g_new(BdrvDirtyBitmapIter, 1);
 635     hbitmap_iter_init(&iter->hbi, bitmap->bitmap, 0);
 636     iter->bitmap = bitmap;
 637     bitmap->active_iterators++;
 638     return iter;
 639 }
 640
 641 void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter)
 642 {
 643     if (!iter) {
 644         return;
 645     }
 646     assert(iter->bitmap->active_iterators > 0);
 647     iter->bitmap->active_iterators--;
 648     g_free(iter);
 649 }
 650
 651 int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)
 652 {
 653     return hbitmap_iter_next(&iter->hbi);
 654 }
 655
 656 /* Called within bdrv_dirty_bitmap_lock..unlock */
 657 void bdrv_set_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,
 658                                   int64_t offset, int64_t bytes)
 659 {
 660     assert(!bdrv_dirty_bitmap_readonly(bitmap));
 661     hbitmap_set(bitmap->bitmap, offset, bytes);
 662 }
 663
 664 void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
 665                            int64_t offset, int64_t bytes)
 666 {
 667     bdrv_dirty_bitmaps_lock(bitmap->bs);
 668     bdrv_set_dirty_bitmap_locked(bitmap, offset, bytes);
 669     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 670 }
 671
 672 /* Called within bdrv_dirty_bitmap_lock..unlock */
 673 void bdrv_reset_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,
 674                                     int64_t offset, int64_t bytes)
 675 {
 676     assert(!bdrv_dirty_bitmap_readonly(bitmap));
 677     hbitmap_reset(bitmap->bitmap, offset, bytes);
 678 }
 679
 680 void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
 681                              int64_t offset, int64_t bytes)
 682 {
 683     bdrv_dirty_bitmaps_lock(bitmap->bs);
 684     bdrv_reset_dirty_bitmap_locked(bitmap, offset, bytes);
 685     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 686 }
 687
 688 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out)
 689 {
 690     assert(!bdrv_dirty_bitmap_readonly(bitmap));
 691     bdrv_dirty_bitmaps_lock(bitmap->bs);
 692     if (!out) {
 693         hbitmap_reset_all(bitmap->bitmap);
 694     } else {
 695         HBitmap *backup = bitmap->bitmap;
 696         bitmap->bitmap = hbitmap_alloc(bitmap->size,
 697                                        hbitmap_granularity(backup));
 698         *out = backup;
 699     }
 700     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 701 }
 702
 703 void bdrv_restore_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *backup)
 704 {
 705     HBitmap *tmp = bitmap->bitmap;
 706     assert(!bdrv_dirty_bitmap_readonly(bitmap));
 707     bitmap->bitmap = backup;
 708     hbitmap_free(tmp);
 709 }
 710
 711 uint64_t bdrv_dirty_bitmap_serialization_size(const BdrvDirtyBitmap *bitmap,
 712                                               uint64_t offset, uint64_t bytes)
 713 {
 714     return hbitmap_serialization_size(bitmap->bitmap, offset, bytes);
 715 }
 716
 717 uint64_t bdrv_dirty_bitmap_serialization_align(const BdrvDirtyBitmap *bitmap)
 718 {
 719     return hbitmap_serialization_align(bitmap->bitmap);
 720 }
 721
 722 void bdrv_dirty_bitmap_serialize_part(const BdrvDirtyBitmap *bitmap,
 723                                       uint8_t *buf, uint64_t offset,
 724                                       uint64_t bytes)
 725 {
 726     hbitmap_serialize_part(bitmap->bitmap, buf, offset, bytes);
 727 }
 728
 729 void bdrv_dirty_bitmap_deserialize_part(BdrvDirtyBitmap *bitmap,
 730                                         uint8_t *buf, uint64_t offset,
 731                                         uint64_t bytes, bool finish)
 732 {
 733     hbitmap_deserialize_part(bitmap->bitmap, buf, offset, bytes, finish);
 734 }
 735
 736 void bdrv_dirty_bitmap_deserialize_zeroes(BdrvDirtyBitmap *bitmap,
 737                                           uint64_t offset, uint64_t bytes,
 738                                           bool finish)
 739 {
 740     hbitmap_deserialize_zeroes(bitmap->bitmap, offset, bytes, finish);
 741 }
 742
 743 void bdrv_dirty_bitmap_deserialize_ones(BdrvDirtyBitmap *bitmap,
 744                                         uint64_t offset, uint64_t bytes,
 745                                         bool finish)
 746 {
 747     hbitmap_deserialize_ones(bitmap->bitmap, offset, bytes, finish);
 748 }
 749
 750 void bdrv_dirty_bitmap_deserialize_finish(BdrvDirtyBitmap *bitmap)
 751 {
 752     hbitmap_deserialize_finish(bitmap->bitmap);
 753 }
 754
 755 void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes)
 756 {
 757     BdrvDirtyBitmap *bitmap;
 758
 759     if (QLIST_EMPTY(&bs->dirty_bitmaps)) {
 760         return;
 761     }
 762
 763     bdrv_dirty_bitmaps_lock(bs);
 764     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
 765         if (!bdrv_dirty_bitmap_enabled(bitmap)) {
 766             continue;
 767         }
 768         assert(!bdrv_dirty_bitmap_readonly(bitmap));
 769         hbitmap_set(bitmap->bitmap, offset, bytes);
 770     }
 771     bdrv_dirty_bitmaps_unlock(bs);
 772 }
 773
 774 /**
 775  * Advance a BdrvDirtyBitmapIter to an arbitrary offset.
 776  */
 777 void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *iter, int64_t offset)
 778 {
 779     hbitmap_iter_init(&iter->hbi, iter->hbi.hb, offset);
 780 }
 781
 782 int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap)
 783 {
 784     return hbitmap_count(bitmap->bitmap);
 785 }
 786
 787 bool bdrv_dirty_bitmap_readonly(const BdrvDirtyBitmap *bitmap)
 788 {
 789     return bitmap->readonly;
 790 }
 791
 792 /* Called with BQL taken. */
 793 void bdrv_dirty_bitmap_set_readonly(BdrvDirtyBitmap *bitmap, bool value)
 794 {
 795     bdrv_dirty_bitmaps_lock(bitmap->bs);
 796     bitmap->readonly = value;
 797     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 798 }
 799
 800 bool bdrv_has_readonly_bitmaps(BlockDriverState *bs)
 801 {
 802     BdrvDirtyBitmap *bm;
 803     QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) {
 804         if (bm->readonly) {
 805             return true;
 806         }
 807     }
 808
 809     return false;
 810 }
 811
 812 /* Called with BQL taken. */
 813 void bdrv_dirty_bitmap_set_persistence(BdrvDirtyBitmap *bitmap, bool persistent)
 814 {
 815     bdrv_dirty_bitmaps_lock(bitmap->bs);
 816     bitmap->persistent = persistent;
 817     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 818 }
 819
 820 /* Called with BQL taken. */
 821 void bdrv_dirty_bitmap_set_inconsistent(BdrvDirtyBitmap *bitmap)
 822 {
 823     bdrv_dirty_bitmaps_lock(bitmap->bs);
 824     assert(bitmap->persistent == true);
 825     bitmap->inconsistent = true;
 826     bitmap->disabled = true;
 827     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 828 }
 829
 830 /* Called with BQL taken. */
 831 void bdrv_dirty_bitmap_skip_store(BdrvDirtyBitmap *bitmap, bool skip)
 832 {
 833     bdrv_dirty_bitmaps_lock(bitmap->bs);
 834     bitmap->skip_store = skip;
 835     bdrv_dirty_bitmaps_unlock(bitmap->bs);
 836 }
 837
 838 bool bdrv_dirty_bitmap_get_persistence(BdrvDirtyBitmap *bitmap)
 839 {
 840     return bitmap->persistent && !bitmap->skip_store;
 841 }
 842
 843 bool bdrv_dirty_bitmap_inconsistent(const BdrvDirtyBitmap *bitmap)
 844 {
 845     return bitmap->inconsistent;
 846 }
 847
 848 BdrvDirtyBitmap *bdrv_dirty_bitmap_first(BlockDriverState *bs)
 849 {
 850     return QLIST_FIRST(&bs->dirty_bitmaps);
 851 }
 852
 853 BdrvDirtyBitmap *bdrv_dirty_bitmap_next(BdrvDirtyBitmap *bitmap)
 854 {
 855     return QLIST_NEXT(bitmap, list);
 856 }
 857
 858 char *bdrv_dirty_bitmap_sha256(const BdrvDirtyBitmap *bitmap, Error **errp)
 859 {
 860     return hbitmap_sha256(bitmap->bitmap, errp);
 861 }
 862
 863 int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t offset,
 864                                     uint64_t bytes)
 865 {
 866     return hbitmap_next_zero(bitmap->bitmap, offset, bytes);
 867 }
 868
 869 bool bdrv_dirty_bitmap_next_dirty_area(BdrvDirtyBitmap *bitmap,
 870                                        uint64_t *offset, uint64_t *bytes)
 871 {
 872     return hbitmap_next_dirty_area(bitmap->bitmap, offset, bytes);
 873 }
 874
 875 /**
 876  * bdrv_merge_dirty_bitmap: merge src into dest.
 877  * Ensures permissions on bitmaps are reasonable; use for public API.
 878  *
 879  * @backup: If provided, make a copy of dest here prior to merge.
 880  */
 881 void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src,
 882                              HBitmap **backup, Error **errp)
 883 {
 884     bool ret;
 885
 886     bdrv_dirty_bitmaps_lock(dest->bs);
 887     if (src->bs != dest->bs) {
 888         bdrv_dirty_bitmaps_lock(src->bs);
 889     }
 890
 891     if (bdrv_dirty_bitmap_check(dest, BDRV_BITMAP_DEFAULT, errp)) {
 892         goto out;
 893     }
 894
 895     if (bdrv_dirty_bitmap_check(src, BDRV_BITMAP_ALLOW_RO, errp)) {
 896         goto out;
 897     }
 898
 899     if (!hbitmap_can_merge(dest->bitmap, src->bitmap)) {
 900         error_setg(errp, "Bitmaps are incompatible and can't be merged");
 901         goto out;
 902     }
 903
 904     ret = bdrv_dirty_bitmap_merge_internal(dest, src, backup, false);
 905     assert(ret);
 906
 907 out:
 908     bdrv_dirty_bitmaps_unlock(dest->bs);
 909     if (src->bs != dest->bs) {
 910         bdrv_dirty_bitmaps_unlock(src->bs);
 911     }
 912 }
 913
 914 /**
 915  * bdrv_dirty_bitmap_merge_internal: merge src into dest.
 916  * Does NOT check bitmap permissions; not suitable for use as public API.
 917  *
 918  * @backup: If provided, make a copy of dest here prior to merge.
 919  * @lock: If true, lock and unlock bitmaps on the way in/out.
 920  * returns true if the merge succeeded; false if unattempted.
 921  */
 922 bool bdrv_dirty_bitmap_merge_internal(BdrvDirtyBitmap *dest,
 923                                       const BdrvDirtyBitmap *src,
 924                                       HBitmap **backup,
 925                                       bool lock)
 926 {
 927     bool ret;
 928
 929     assert(!bdrv_dirty_bitmap_readonly(dest));
 930     assert(!bdrv_dirty_bitmap_inconsistent(dest));
 931     assert(!bdrv_dirty_bitmap_inconsistent(src));
 932
 933     if (lock) {
 934         bdrv_dirty_bitmaps_lock(dest->bs);
 935         if (src->bs != dest->bs) {
 936             bdrv_dirty_bitmaps_lock(src->bs);
 937         }
 938     }
 939
 940     if (backup) {
 941         *backup = dest->bitmap;
 942         dest->bitmap = hbitmap_alloc(dest->size, hbitmap_granularity(*backup));
 943         ret = hbitmap_merge(*backup, src->bitmap, dest->bitmap);
 944     } else {
 945         ret = hbitmap_merge(dest->bitmap, src->bitmap, dest->bitmap);
 946     }
 947
 948     if (lock) {
 949         bdrv_dirty_bitmaps_unlock(dest->bs);
 950         if (src->bs != dest->bs) {
 951             bdrv_dirty_bitmaps_unlock(src->bs);
 952         }
 953     }
 954
 955     return ret;
 956 }