include/block/block.h

   1 #ifndef BLOCK_H
   2 #define BLOCK_H
   3
   4 #include "block/aio.h"
   5 #include "qemu/iov.h"
   6 #include "qemu/option.h"
   7 #include "qemu/coroutine.h"
   8 #include "block/accounting.h"
   9 #include "block/dirty-bitmap.h"
  10 #include "qapi/qmp/qobject.h"
  11 #include "qapi-types.h"
  12 #include "qemu/hbitmap.h"
  13
  14 /* block.c */
  15 typedef struct BlockDriver BlockDriver;
  16 typedef struct BlockJob BlockJob;
  17 typedef struct BdrvChild BdrvChild;
  18 typedef struct BdrvChildRole BdrvChildRole;
  19 typedef struct BlockJobTxn BlockJobTxn;
  20
  21 typedef struct BlockDriverInfo {
  22     /* in bytes, 0 if irrelevant */
  23     int cluster_size;
  24     /* offset at which the VM state can be saved (0 if not possible) */
  25     int64_t vm_state_offset;
  26     bool is_dirty;
  27     /*
  28      * True if unallocated blocks read back as zeroes. This is equivalent
  29      * to the LBPRZ flag in the SCSI logical block provisioning page.
  30      */
  31     bool unallocated_blocks_are_zero;
  32     /*
  33      * True if the driver can optimize writing zeroes by unmapping
  34      * sectors. This is equivalent to the BLKDISCARDZEROES ioctl in Linux
  35      * with the difference that in qemu a discard is allowed to silently
  36      * fail. Therefore we have to use bdrv_pwrite_zeroes with the
  37      * BDRV_REQ_MAY_UNMAP flag for an optimized zero write with unmapping.
  38      * After this call the driver has to guarantee that the contents read
  39      * back as zero. It is additionally required that the block device is
  40      * opened with BDRV_O_UNMAP flag for this to work.
  41      */
  42     bool can_write_zeroes_with_unmap;
  43     /*
  44      * True if this block driver only supports compressed writes
  45      */
  46     bool needs_compressed_writes;
  47 } BlockDriverInfo;
  48
  49 typedef struct BlockFragInfo {
  50     uint64_t allocated_clusters;
  51     uint64_t total_clusters;
  52     uint64_t fragmented_clusters;
  53     uint64_t compressed_clusters;
  54 } BlockFragInfo;
  55
  56 typedef enum {
  57     BDRV_REQ_COPY_ON_READ       = 0x1,
  58     BDRV_REQ_ZERO_WRITE         = 0x2,
  59     /* The BDRV_REQ_MAY_UNMAP flag is used to indicate that the block driver
  60      * is allowed to optimize a write zeroes request by unmapping (discarding)
  61      * blocks if it is guaranteed that the result will read back as
  62      * zeroes. The flag is only passed to the driver if the block device is
  63      * opened with BDRV_O_UNMAP.
  64      */
  65     BDRV_REQ_MAY_UNMAP          = 0x4,
  66     BDRV_REQ_NO_SERIALISING     = 0x8,
  67     BDRV_REQ_FUA                = 0x10,
  68     BDRV_REQ_WRITE_COMPRESSED   = 0x20,
  69
  70     /* Mask of valid flags */
  71     BDRV_REQ_MASK               = 0x3f,
  72 } BdrvRequestFlags;
  73
  74 typedef struct BlockSizes {
  75     uint32_t phys;
  76     uint32_t log;
  77 } BlockSizes;
  78
  79 typedef struct HDGeometry {
  80     uint32_t heads;
  81     uint32_t sectors;
  82     uint32_t cylinders;
  83 } HDGeometry;
  84
  85 #define BDRV_O_RDWR        0x0002
  86 #define BDRV_O_SNAPSHOT    0x0008 /* open the file read only and save writes in a snapshot */
  87 #define BDRV_O_TEMPORARY   0x0010 /* delete the file after use */
  88 #define BDRV_O_NOCACHE     0x0020 /* do not use the host page cache */
  89 #define BDRV_O_NATIVE_AIO  0x0080 /* use native AIO instead of the thread pool */
  90 #define BDRV_O_NO_BACKING  0x0100 /* don't open the backing file */
  91 #define BDRV_O_NO_FLUSH    0x0200 /* disable flushing on this disk */
  92 #define BDRV_O_COPY_ON_READ 0x0400 /* copy read backing sectors into image */
  93 #define BDRV_O_INACTIVE    0x0800  /* consistency hint for migration handoff */
  94 #define BDRV_O_CHECK       0x1000  /* open solely for consistency check */
  95 #define BDRV_O_ALLOW_RDWR  0x2000  /* allow reopen to change from r/o to r/w */
  96 #define BDRV_O_UNMAP       0x4000  /* execute guest UNMAP/TRIM operations */
  97 #define BDRV_O_PROTOCOL    0x8000  /* if no block driver is explicitly given:
  98                                       select an appropriate protocol driver,
  99                                       ignoring the format layer */
 100 #define BDRV_O_NO_IO       0x10000 /* don't initialize for I/O */
 101
 102 #define BDRV_O_CACHE_MASK  (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH)
 103
 104
 105 /* Option names of options parsed by the block layer */
 106
 107 #define BDRV_OPT_CACHE_WB       "cache.writeback"
 108 #define BDRV_OPT_CACHE_DIRECT   "cache.direct"
 109 #define BDRV_OPT_CACHE_NO_FLUSH "cache.no-flush"
 110 #define BDRV_OPT_READ_ONLY      "read-only"
 111 #define BDRV_OPT_DISCARD        "discard"
 112
 113
 114 #define BDRV_SECTOR_BITS   9
 115 #define BDRV_SECTOR_SIZE   (1ULL << BDRV_SECTOR_BITS)
 116 #define BDRV_SECTOR_MASK   ~(BDRV_SECTOR_SIZE - 1)
 117
 118 #define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \
 119                                      INT_MAX >> BDRV_SECTOR_BITS)
 120
 121 /*
 122  * Allocation status flags
 123  * BDRV_BLOCK_DATA: data is read from a file returned by bdrv_get_block_status.
 124  * BDRV_BLOCK_ZERO: sectors read as zero
 125  * BDRV_BLOCK_OFFSET_VALID: sector stored as raw data in a file returned by
 126  *                          bdrv_get_block_status.
 127  * BDRV_BLOCK_ALLOCATED: the content of the block is determined by this
 128  *                       layer (as opposed to the backing file)
 129  * BDRV_BLOCK_RAW: used internally to indicate that the request
 130  *                 was answered by the raw driver and that one
 131  *                 should look in bs->file directly.
 132  *
 133  * If BDRV_BLOCK_OFFSET_VALID is set, bits 9-62 represent the offset in
 134  * bs->file where sector data can be read from as raw data.
 135  *
 136  * DATA == 0 && ZERO == 0 means that data is read from backing_hd if present.
 137  *
 138  * DATA ZERO OFFSET_VALID
 139  *  t    t        t       sectors read as zero, bs->file is zero at offset
 140  *  t    f        t       sectors read as valid from bs->file at offset
 141  *  f    t        t       sectors preallocated, read as zero, bs->file not
 142  *                        necessarily zero at offset
 143  *  f    f        t       sectors preallocated but read from backing_hd,
 144  *                        bs->file contains garbage at offset
 145  *  t    t        f       sectors preallocated, read as zero, unknown offset
 146  *  t    f        f       sectors read from unknown file or offset
 147  *  f    t        f       not allocated or unknown offset, read as zero
 148  *  f    f        f       not allocated or unknown offset, read from backing_hd
 149  */
 150 #define BDRV_BLOCK_DATA         0x01
 151 #define BDRV_BLOCK_ZERO         0x02
 152 #define BDRV_BLOCK_OFFSET_VALID 0x04
 153 #define BDRV_BLOCK_RAW          0x08
 154 #define BDRV_BLOCK_ALLOCATED    0x10
 155 #define BDRV_BLOCK_OFFSET_MASK  BDRV_SECTOR_MASK
 156
 157 typedef QSIMPLEQ_HEAD(BlockReopenQueue, BlockReopenQueueEntry) BlockReopenQueue;
 158
 159 typedef struct BDRVReopenState {
 160     BlockDriverState *bs;
 161     int flags;
 162     QDict *options;
 163     QDict *explicit_options;
 164     void *opaque;
 165 } BDRVReopenState;
 166
 167 /*
 168  * Block operation types
 169  */
 170 typedef enum BlockOpType {
 171     BLOCK_OP_TYPE_BACKUP_SOURCE,
 172     BLOCK_OP_TYPE_BACKUP_TARGET,
 173     BLOCK_OP_TYPE_CHANGE,
 174     BLOCK_OP_TYPE_COMMIT_SOURCE,
 175     BLOCK_OP_TYPE_COMMIT_TARGET,
 176     BLOCK_OP_TYPE_DATAPLANE,
 177     BLOCK_OP_TYPE_DRIVE_DEL,
 178     BLOCK_OP_TYPE_EJECT,
 179     BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
 180     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT,
 181     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
 182     BLOCK_OP_TYPE_MIRROR_SOURCE,
 183     BLOCK_OP_TYPE_MIRROR_TARGET,
 184     BLOCK_OP_TYPE_RESIZE,
 185     BLOCK_OP_TYPE_STREAM,
 186     BLOCK_OP_TYPE_REPLACE,
 187     BLOCK_OP_TYPE_MAX,
 188 } BlockOpType;
 189
 190 /* disk I/O throttling */
 191 void bdrv_init(void);
 192 void bdrv_init_with_whitelist(void);
 193 bool bdrv_uses_whitelist(void);
 194 BlockDriver *bdrv_find_protocol(const char *filename,
 195                                 bool allow_protocol_prefix,
 196                                 Error **errp);
 197 BlockDriver *bdrv_find_format(const char *format_name);
 198 int bdrv_create(BlockDriver *drv, const char* filename,
 199                 QemuOpts *opts, Error **errp);
 200 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp);
 201 BlockDriverState *bdrv_new(void);
 202 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top);
 203 void bdrv_replace_in_backing_chain(BlockDriverState *old,
 204                                    BlockDriverState *new);
 205
 206 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough);
 207 int bdrv_parse_discard_flags(const char *mode, int *flags);
 208 BdrvChild *bdrv_open_child(const char *filename,
 209                            QDict *options, const char *bdref_key,
 210                            BlockDriverState* parent,
 211                            const BdrvChildRole *child_role,
 212                            bool allow_none, Error **errp);
 213 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd);
 214 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
 215                            const char *bdref_key, Error **errp);
 216 BlockDriverState *bdrv_open(const char *filename, const char *reference,
 217                             QDict *options, int flags, Error **errp);
 218 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
 219                                     BlockDriverState *bs,
 220                                     QDict *options, int flags);
 221 int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **errp);
 222 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp);
 223 int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
 224                         BlockReopenQueue *queue, Error **errp);
 225 void bdrv_reopen_commit(BDRVReopenState *reopen_state);
 226 void bdrv_reopen_abort(BDRVReopenState *reopen_state);
 227 int bdrv_read(BdrvChild *child, int64_t sector_num,
 228               uint8_t *buf, int nb_sectors);
 229 int bdrv_write(BdrvChild *child, int64_t sector_num,
 230                const uint8_t *buf, int nb_sectors);
 231 int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
 232                        int count, BdrvRequestFlags flags);
 233 int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
 234 int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes);
 235 int bdrv_preadv(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
 236 int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes);
 237 int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
 238 int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
 239                      const void *buf, int count);
 240 int coroutine_fn bdrv_co_readv(BdrvChild *child, int64_t sector_num,
 241                                int nb_sectors, QEMUIOVector *qiov);
 242 int coroutine_fn bdrv_co_writev(BdrvChild *child, int64_t sector_num,
 243                                int nb_sectors, QEMUIOVector *qiov);
 244 /*
 245  * Efficiently zero a region of the disk image.  Note that this is a regular
 246  * I/O request like read or write and should have a reasonable size.  This
 247  * function is not suitable for zeroing the entire image in a single request
 248  * because it may allocate memory for the entire region.
 249  */
 250 int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
 251                                        int count, BdrvRequestFlags flags);
 252 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
 253     const char *backing_file);
 254 int bdrv_get_backing_file_depth(BlockDriverState *bs);
 255 void bdrv_refresh_filename(BlockDriverState *bs);
 256 int bdrv_truncate(BlockDriverState *bs, int64_t offset);
 257 int64_t bdrv_nb_sectors(BlockDriverState *bs);
 258 int64_t bdrv_getlength(BlockDriverState *bs);
 259 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
 260 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
 261 void bdrv_refresh_limits(BlockDriverState *bs, Error **errp);
 262 int bdrv_commit(BlockDriverState *bs);
 263 int bdrv_change_backing_file(BlockDriverState *bs,
 264     const char *backing_file, const char *backing_fmt);
 265 void bdrv_register(BlockDriver *bdrv);
 266 int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
 267                            BlockDriverState *base,
 268                            const char *backing_file_str);
 269 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
 270                                     BlockDriverState *bs);
 271 BlockDriverState *bdrv_find_base(BlockDriverState *bs);
 272
 273
 274 typedef struct BdrvCheckResult {
 275     int corruptions;
 276     int leaks;
 277     int check_errors;
 278     int corruptions_fixed;
 279     int leaks_fixed;
 280     int64_t image_end_offset;
 281     BlockFragInfo bfi;
 282 } BdrvCheckResult;
 283
 284 typedef enum {
 285     BDRV_FIX_LEAKS    = 1,
 286     BDRV_FIX_ERRORS   = 2,
 287 } BdrvCheckMode;
 288
 289 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
 290
 291 /* The units of offset and total_work_size may be chosen arbitrarily by the
 292  * block driver; total_work_size may change during the course of the amendment
 293  * operation */
 294 typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
 295                                       int64_t total_work_size, void *opaque);
 296 int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
 297                        BlockDriverAmendStatusCB *status_cb, void *cb_opaque);
 298
 299 /* external snapshots */
 300 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
 301                                       BlockDriverState *candidate);
 302 bool bdrv_is_first_non_filter(BlockDriverState *candidate);
 303
 304 /* check if a named node can be replaced when doing drive-mirror */
 305 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
 306                                         const char *node_name, Error **errp);
 307
 308 /* async block I/O */
 309 BlockAIOCB *bdrv_aio_readv(BdrvChild *child, int64_t sector_num,
 310                            QEMUIOVector *iov, int nb_sectors,
 311                            BlockCompletionFunc *cb, void *opaque);
 312 BlockAIOCB *bdrv_aio_writev(BdrvChild *child, int64_t sector_num,
 313                             QEMUIOVector *iov, int nb_sectors,
 314                             BlockCompletionFunc *cb, void *opaque);
 315 BlockAIOCB *bdrv_aio_flush(BlockDriverState *bs,
 316                            BlockCompletionFunc *cb, void *opaque);
 317 void bdrv_aio_cancel(BlockAIOCB *acb);
 318 void bdrv_aio_cancel_async(BlockAIOCB *acb);
 319
 320 /* sg packet commands */
 321 int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf);
 322
 323 /* Invalidate any cached metadata used by image formats */
 324 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp);
 325 void bdrv_invalidate_cache_all(Error **errp);
 326 int bdrv_inactivate_all(void);
 327
 328 /* Ensure contents are flushed to disk.  */
 329 int bdrv_flush(BlockDriverState *bs);
 330 int coroutine_fn bdrv_co_flush(BlockDriverState *bs);
 331 int bdrv_flush_all(void);
 332 void bdrv_close_all(void);
 333 void bdrv_drain(BlockDriverState *bs);
 334 void coroutine_fn bdrv_co_drain(BlockDriverState *bs);
 335 void bdrv_drain_all_begin(void);
 336 void bdrv_drain_all_end(void);
 337 void bdrv_drain_all(void);
 338
 339 #define BDRV_POLL_WHILE(bs, cond) ({                       \
 340     bool waited_ = false;                                  \
 341     BlockDriverState *bs_ = (bs);                          \
 342     AioContext *ctx_ = bdrv_get_aio_context(bs_);          \
 343     if (aio_context_in_iothread(ctx_)) {                   \
 344         while ((cond)) {                                   \
 345             aio_poll(ctx_, true);                          \
 346             waited_ = true;                                \
 347         }                                                  \
 348     } else {                                               \
 349         assert(qemu_get_current_aio_context() ==           \
 350                qemu_get_aio_context());                    \
 351         /* Ask bdrv_dec_in_flight to wake up the main      \
 352          * QEMU AioContext.  Extra I/O threads never take  \
 353          * other I/O threads' AioContexts (see for example \
 354          * block_job_defer_to_main_loop for how to do it). \
 355          */                                                \
 356         assert(!bs_->wakeup);                              \
 357         bs_->wakeup = true;                                \
 358         while ((cond)) {                                   \
 359             aio_context_release(ctx_);                     \
 360             aio_poll(qemu_get_aio_context(), true);        \
 361             aio_context_acquire(ctx_);                     \
 362             waited_ = true;                                \
 363         }                                                  \
 364         bs_->wakeup = false;                               \
 365     }                                                      \
 366     waited_; })
 367
 368 int bdrv_pdiscard(BlockDriverState *bs, int64_t offset, int count);
 369 int bdrv_co_pdiscard(BlockDriverState *bs, int64_t offset, int count);
 370 int bdrv_has_zero_init_1(BlockDriverState *bs);
 371 int bdrv_has_zero_init(BlockDriverState *bs);
 372 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs);
 373 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
 374 int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num,
 375                               int nb_sectors, int *pnum,
 376                               BlockDriverState **file);
 377 int64_t bdrv_get_block_status_above(BlockDriverState *bs,
 378                                     BlockDriverState *base,
 379                                     int64_t sector_num,
 380                                     int nb_sectors, int *pnum,
 381                                     BlockDriverState **file);
 382 int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
 383                       int *pnum);
 384 int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
 385                             int64_t sector_num, int nb_sectors, int *pnum);
 386
 387 bool bdrv_is_read_only(BlockDriverState *bs);
 388 bool bdrv_is_sg(BlockDriverState *bs);
 389 bool bdrv_is_inserted(BlockDriverState *bs);
 390 int bdrv_media_changed(BlockDriverState *bs);
 391 void bdrv_lock_medium(BlockDriverState *bs, bool locked);
 392 void bdrv_eject(BlockDriverState *bs, bool eject_flag);
 393 const char *bdrv_get_format_name(BlockDriverState *bs);
 394 BlockDriverState *bdrv_find_node(const char *node_name);
 395 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp);
 396 BlockDriverState *bdrv_lookup_bs(const char *device,
 397                                  const char *node_name,
 398                                  Error **errp);
 399 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
 400 BlockDriverState *bdrv_next_node(BlockDriverState *bs);
 401
 402 typedef struct BdrvNextIterator {
 403     enum {
 404         BDRV_NEXT_BACKEND_ROOTS,
 405         BDRV_NEXT_MONITOR_OWNED,
 406     } phase;
 407     BlockBackend *blk;
 408     BlockDriverState *bs;
 409 } BdrvNextIterator;
 410
 411 BlockDriverState *bdrv_first(BdrvNextIterator *it);
 412 BlockDriverState *bdrv_next(BdrvNextIterator *it);
 413
 414 BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs);
 415 bool bdrv_is_encrypted(BlockDriverState *bs);
 416 bool bdrv_key_required(BlockDriverState *bs);
 417 int bdrv_set_key(BlockDriverState *bs, const char *key);
 418 void bdrv_add_key(BlockDriverState *bs, const char *key, Error **errp);
 419 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
 420                          void *opaque);
 421 const char *bdrv_get_node_name(const BlockDriverState *bs);
 422 const char *bdrv_get_device_name(const BlockDriverState *bs);
 423 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
 424 int bdrv_get_flags(BlockDriverState *bs);
 425 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
 426 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs);
 427 void bdrv_round_sectors_to_clusters(BlockDriverState *bs,
 428                                     int64_t sector_num, int nb_sectors,
 429                                     int64_t *cluster_sector_num,
 430                                     int *cluster_nb_sectors);
 431 void bdrv_round_to_clusters(BlockDriverState *bs,
 432                             int64_t offset, unsigned int bytes,
 433                             int64_t *cluster_offset,
 434                             unsigned int *cluster_bytes);
 435
 436 const char *bdrv_get_encrypted_filename(BlockDriverState *bs);
 437 void bdrv_get_backing_filename(BlockDriverState *bs,
 438                                char *filename, int filename_size);
 439 void bdrv_get_full_backing_filename(BlockDriverState *bs,
 440                                     char *dest, size_t sz, Error **errp);
 441 void bdrv_get_full_backing_filename_from_filename(const char *backed,
 442                                                   const char *backing,
 443                                                   char *dest, size_t sz,
 444                                                   Error **errp);
 445
 446 int path_has_protocol(const char *path);
 447 int path_is_absolute(const char *path);
 448 void path_combine(char *dest, int dest_size,
 449                   const char *base_path,
 450                   const char *filename);
 451
 452 int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 453 int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 454 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
 455                       int64_t pos, int size);
 456
 457 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
 458                       int64_t pos, int size);
 459
 460 void bdrv_img_create(const char *filename, const char *fmt,
 461                      const char *base_filename, const char *base_fmt,
 462                      char *options, uint64_t img_size, int flags,
 463                      Error **errp, bool quiet);
 464
 465 /* Returns the alignment in bytes that is required so that no bounce buffer
 466  * is required throughout the stack */
 467 size_t bdrv_min_mem_align(BlockDriverState *bs);
 468 /* Returns optimal alignment in bytes for bounce buffer */
 469 size_t bdrv_opt_mem_align(BlockDriverState *bs);
 470 void *qemu_blockalign(BlockDriverState *bs, size_t size);
 471 void *qemu_blockalign0(BlockDriverState *bs, size_t size);
 472 void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
 473 void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
 474 bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);
 475
 476 void bdrv_enable_copy_on_read(BlockDriverState *bs);
 477 void bdrv_disable_copy_on_read(BlockDriverState *bs);
 478
 479 void bdrv_ref(BlockDriverState *bs);
 480 void bdrv_unref(BlockDriverState *bs);
 481 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child);
 482 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
 483                              BlockDriverState *child_bs,
 484                              const char *child_name,
 485                              const BdrvChildRole *child_role);
 486
 487 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
 488 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);
 489 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason);
 490 void bdrv_op_block_all(BlockDriverState *bs, Error *reason);
 491 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason);
 492 bool bdrv_op_blocker_is_empty(BlockDriverState *bs);
 493
 494 #define BLKDBG_EVENT(child, evt) \
 495     do { \
 496         if (child) { \
 497             bdrv_debug_event(child->bs, evt); \
 498         } \
 499     } while (0)
 500
 501 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
 502
 503 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
 504                            const char *tag);
 505 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag);
 506 int bdrv_debug_resume(BlockDriverState *bs, const char *tag);
 507 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag);
 508
 509 /**
 510  * bdrv_get_aio_context:
 511  *
 512  * Returns: the currently bound #AioContext
 513  */
 514 AioContext *bdrv_get_aio_context(BlockDriverState *bs);
 515
 516 /**
 517  * bdrv_set_aio_context:
 518  *
 519  * Changes the #AioContext used for fd handlers, timers, and BHs by this
 520  * BlockDriverState and all its children.
 521  *
 522  * This function must be called with iothread lock held.
 523  */
 524 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context);
 525 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
 526 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
 527
 528 void bdrv_io_plug(BlockDriverState *bs);
 529 void bdrv_io_unplug(BlockDriverState *bs);
 530 void bdrv_io_unplugged_begin(BlockDriverState *bs);
 531 void bdrv_io_unplugged_end(BlockDriverState *bs);
 532
 533 /**
 534  * bdrv_drained_begin:
 535  *
 536  * Begin a quiesced section for exclusive access to the BDS, by disabling
 537  * external request sources including NBD server and device model. Note that
 538  * this doesn't block timers or coroutines from submitting more requests, which
 539  * means block_job_pause is still necessary.
 540  *
 541  * This function can be recursive.
 542  */
 543 void bdrv_drained_begin(BlockDriverState *bs);
 544
 545 /**
 546  * bdrv_drained_end:
 547  *
 548  * End a quiescent section started by bdrv_drained_begin().
 549  */
 550 void bdrv_drained_end(BlockDriverState *bs);
 551
 552 void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
 553                     Error **errp);
 554 void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
 555
 556 #endif