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_write_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 } BdrvRequestFlags;
  69
  70 typedef struct BlockSizes {
  71     uint32_t phys;
  72     uint32_t log;
  73 } BlockSizes;
  74
  75 typedef struct HDGeometry {
  76     uint32_t heads;
  77     uint32_t sectors;
  78     uint32_t cylinders;
  79 } HDGeometry;
  80
  81 #define BDRV_O_RDWR        0x0002
  82 #define BDRV_O_SNAPSHOT    0x0008 /* open the file read only and save writes in a snapshot */
  83 #define BDRV_O_TEMPORARY   0x0010 /* delete the file after use */
  84 #define BDRV_O_NOCACHE     0x0020 /* do not use the host page cache */
  85 #define BDRV_O_NATIVE_AIO  0x0080 /* use native AIO instead of the thread pool */
  86 #define BDRV_O_NO_BACKING  0x0100 /* don't open the backing file */
  87 #define BDRV_O_NO_FLUSH    0x0200 /* disable flushing on this disk */
  88 #define BDRV_O_COPY_ON_READ 0x0400 /* copy read backing sectors into image */
  89 #define BDRV_O_INACTIVE    0x0800  /* consistency hint for migration handoff */
  90 #define BDRV_O_CHECK       0x1000  /* open solely for consistency check */
  91 #define BDRV_O_ALLOW_RDWR  0x2000  /* allow reopen to change from r/o to r/w */
  92 #define BDRV_O_UNMAP       0x4000  /* execute guest UNMAP/TRIM operations */
  93 #define BDRV_O_PROTOCOL    0x8000  /* if no block driver is explicitly given:
  94                                       select an appropriate protocol driver,
  95                                       ignoring the format layer */
  96 #define BDRV_O_NO_IO       0x10000 /* don't initialize for I/O */
  97
  98 #define BDRV_O_CACHE_MASK  (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH)
  99
 100
 101 /* Option names of options parsed by the block layer */
 102
 103 #define BDRV_OPT_CACHE_WB       "cache.writeback"
 104 #define BDRV_OPT_CACHE_DIRECT   "cache.direct"
 105 #define BDRV_OPT_CACHE_NO_FLUSH "cache.no-flush"
 106
 107
 108 #define BDRV_SECTOR_BITS   9
 109 #define BDRV_SECTOR_SIZE   (1ULL << BDRV_SECTOR_BITS)
 110 #define BDRV_SECTOR_MASK   ~(BDRV_SECTOR_SIZE - 1)
 111
 112 #define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \
 113                                      INT_MAX >> BDRV_SECTOR_BITS)
 114
 115 /*
 116  * Allocation status flags
 117  * BDRV_BLOCK_DATA: data is read from a file returned by bdrv_get_block_status.
 118  * BDRV_BLOCK_ZERO: sectors read as zero
 119  * BDRV_BLOCK_OFFSET_VALID: sector stored as raw data in a file returned by
 120  *                          bdrv_get_block_status.
 121  * BDRV_BLOCK_ALLOCATED: the content of the block is determined by this
 122  *                       layer (as opposed to the backing file)
 123  * BDRV_BLOCK_RAW: used internally to indicate that the request
 124  *                 was answered by the raw driver and that one
 125  *                 should look in bs->file directly.
 126  *
 127  * If BDRV_BLOCK_OFFSET_VALID is set, bits 9-62 represent the offset in
 128  * bs->file where sector data can be read from as raw data.
 129  *
 130  * DATA == 0 && ZERO == 0 means that data is read from backing_hd if present.
 131  *
 132  * DATA ZERO OFFSET_VALID
 133  *  t    t        t       sectors read as zero, bs->file is zero at offset
 134  *  t    f        t       sectors read as valid from bs->file at offset
 135  *  f    t        t       sectors preallocated, read as zero, bs->file not
 136  *                        necessarily zero at offset
 137  *  f    f        t       sectors preallocated but read from backing_hd,
 138  *                        bs->file contains garbage at offset
 139  *  t    t        f       sectors preallocated, read as zero, unknown offset
 140  *  t    f        f       sectors read from unknown file or offset
 141  *  f    t        f       not allocated or unknown offset, read as zero
 142  *  f    f        f       not allocated or unknown offset, read from backing_hd
 143  */
 144 #define BDRV_BLOCK_DATA         0x01
 145 #define BDRV_BLOCK_ZERO         0x02
 146 #define BDRV_BLOCK_OFFSET_VALID 0x04
 147 #define BDRV_BLOCK_RAW          0x08
 148 #define BDRV_BLOCK_ALLOCATED    0x10
 149 #define BDRV_BLOCK_OFFSET_MASK  BDRV_SECTOR_MASK
 150
 151 typedef QSIMPLEQ_HEAD(BlockReopenQueue, BlockReopenQueueEntry) BlockReopenQueue;
 152
 153 typedef struct BDRVReopenState {
 154     BlockDriverState *bs;
 155     int flags;
 156     QDict *options;
 157     QDict *explicit_options;
 158     void *opaque;
 159 } BDRVReopenState;
 160
 161 /*
 162  * Block operation types
 163  */
 164 typedef enum BlockOpType {
 165     BLOCK_OP_TYPE_BACKUP_SOURCE,
 166     BLOCK_OP_TYPE_BACKUP_TARGET,
 167     BLOCK_OP_TYPE_CHANGE,
 168     BLOCK_OP_TYPE_COMMIT_SOURCE,
 169     BLOCK_OP_TYPE_COMMIT_TARGET,
 170     BLOCK_OP_TYPE_DATAPLANE,
 171     BLOCK_OP_TYPE_DRIVE_DEL,
 172     BLOCK_OP_TYPE_EJECT,
 173     BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
 174     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT,
 175     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
 176     BLOCK_OP_TYPE_MIRROR_SOURCE,
 177     BLOCK_OP_TYPE_MIRROR_TARGET,
 178     BLOCK_OP_TYPE_RESIZE,
 179     BLOCK_OP_TYPE_STREAM,
 180     BLOCK_OP_TYPE_REPLACE,
 181     BLOCK_OP_TYPE_MAX,
 182 } BlockOpType;
 183
 184 void bdrv_info_print(Monitor *mon, const QObject *data);
 185 void bdrv_info(Monitor *mon, QObject **ret_data);
 186 void bdrv_stats_print(Monitor *mon, const QObject *data);
 187 void bdrv_info_stats(Monitor *mon, QObject **ret_data);
 188
 189 /* disk I/O throttling */
 190 void bdrv_init(void);
 191 void bdrv_init_with_whitelist(void);
 192 bool bdrv_uses_whitelist(void);
 193 BlockDriver *bdrv_find_protocol(const char *filename,
 194                                 bool allow_protocol_prefix,
 195                                 Error **errp);
 196 BlockDriver *bdrv_find_format(const char *format_name);
 197 int bdrv_create(BlockDriver *drv, const char* filename,
 198                 QemuOpts *opts, Error **errp);
 199 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp);
 200 BlockDriverState *bdrv_new(void);
 201 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top);
 202 void bdrv_replace_in_backing_chain(BlockDriverState *old,
 203                                    BlockDriverState *new);
 204
 205 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough);
 206 int bdrv_parse_discard_flags(const char *mode, int *flags);
 207 BdrvChild *bdrv_open_child(const char *filename,
 208                            QDict *options, const char *bdref_key,
 209                            BlockDriverState* parent,
 210                            const BdrvChildRole *child_role,
 211                            bool allow_none, Error **errp);
 212 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd);
 213 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
 214                            const char *bdref_key, Error **errp);
 215 BlockDriverState *bdrv_open(const char *filename, const char *reference,
 216                             QDict *options, int flags, Error **errp);
 217 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
 218                                     BlockDriverState *bs,
 219                                     QDict *options, int flags);
 220 int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp);
 221 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp);
 222 int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
 223                         BlockReopenQueue *queue, Error **errp);
 224 void bdrv_reopen_commit(BDRVReopenState *reopen_state);
 225 void bdrv_reopen_abort(BDRVReopenState *reopen_state);
 226 int bdrv_read(BlockDriverState *bs, int64_t sector_num,
 227               uint8_t *buf, int nb_sectors);
 228 int bdrv_write(BlockDriverState *bs, int64_t sector_num,
 229                const uint8_t *buf, int nb_sectors);
 230 int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num,
 231                int nb_sectors, BdrvRequestFlags flags);
 232 BlockAIOCB *bdrv_aio_write_zeroes(BlockDriverState *bs, int64_t sector_num,
 233                                   int nb_sectors, BdrvRequestFlags flags,
 234                                   BlockCompletionFunc *cb, void *opaque);
 235 int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags);
 236 int bdrv_pread(BlockDriverState *bs, int64_t offset,
 237                void *buf, int count);
 238 int bdrv_pwrite(BlockDriverState *bs, int64_t offset,
 239                 const void *buf, int count);
 240 int bdrv_pwritev(BlockDriverState *bs, int64_t offset, QEMUIOVector *qiov);
 241 int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset,
 242     const void *buf, int count);
 243 int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num,
 244     int nb_sectors, QEMUIOVector *qiov);
 245 int coroutine_fn bdrv_co_readv_no_serialising(BlockDriverState *bs,
 246     int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
 247 int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num,
 248     int nb_sectors, QEMUIOVector *qiov);
 249 /*
 250  * Efficiently zero a region of the disk image.  Note that this is a regular
 251  * I/O request like read or write and should have a reasonable size.  This
 252  * function is not suitable for zeroing the entire image in a single request
 253  * because it may allocate memory for the entire region.
 254  */
 255 int coroutine_fn bdrv_co_write_zeroes(BlockDriverState *bs, int64_t sector_num,
 256     int nb_sectors, BdrvRequestFlags flags);
 257 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
 258     const char *backing_file);
 259 int bdrv_get_backing_file_depth(BlockDriverState *bs);
 260 void bdrv_refresh_filename(BlockDriverState *bs);
 261 int bdrv_truncate(BlockDriverState *bs, int64_t offset);
 262 int64_t bdrv_nb_sectors(BlockDriverState *bs);
 263 int64_t bdrv_getlength(BlockDriverState *bs);
 264 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
 265 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
 266 void bdrv_refresh_limits(BlockDriverState *bs, Error **errp);
 267 int bdrv_commit(BlockDriverState *bs);
 268 int bdrv_change_backing_file(BlockDriverState *bs,
 269     const char *backing_file, const char *backing_fmt);
 270 void bdrv_register(BlockDriver *bdrv);
 271 int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
 272                            BlockDriverState *base,
 273                            const char *backing_file_str);
 274 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
 275                                     BlockDriverState *bs);
 276 BlockDriverState *bdrv_find_base(BlockDriverState *bs);
 277
 278
 279 typedef struct BdrvCheckResult {
 280     int corruptions;
 281     int leaks;
 282     int check_errors;
 283     int corruptions_fixed;
 284     int leaks_fixed;
 285     int64_t image_end_offset;
 286     BlockFragInfo bfi;
 287 } BdrvCheckResult;
 288
 289 typedef enum {
 290     BDRV_FIX_LEAKS    = 1,
 291     BDRV_FIX_ERRORS   = 2,
 292 } BdrvCheckMode;
 293
 294 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
 295
 296 /* The units of offset and total_work_size may be chosen arbitrarily by the
 297  * block driver; total_work_size may change during the course of the amendment
 298  * operation */
 299 typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
 300                                       int64_t total_work_size, void *opaque);
 301 int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
 302                        BlockDriverAmendStatusCB *status_cb, void *cb_opaque);
 303
 304 /* external snapshots */
 305 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
 306                                       BlockDriverState *candidate);
 307 bool bdrv_is_first_non_filter(BlockDriverState *candidate);
 308
 309 /* check if a named node can be replaced when doing drive-mirror */
 310 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
 311                                         const char *node_name, Error **errp);
 312
 313 /* async block I/O */
 314 BlockAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num,
 315                            QEMUIOVector *iov, int nb_sectors,
 316                            BlockCompletionFunc *cb, void *opaque);
 317 BlockAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num,
 318                             QEMUIOVector *iov, int nb_sectors,
 319                             BlockCompletionFunc *cb, void *opaque);
 320 BlockAIOCB *bdrv_aio_flush(BlockDriverState *bs,
 321                            BlockCompletionFunc *cb, void *opaque);
 322 BlockAIOCB *bdrv_aio_discard(BlockDriverState *bs,
 323                              int64_t sector_num, int nb_sectors,
 324                              BlockCompletionFunc *cb, void *opaque);
 325 void bdrv_aio_cancel(BlockAIOCB *acb);
 326 void bdrv_aio_cancel_async(BlockAIOCB *acb);
 327
 328 typedef struct BlockRequest {
 329     /* Fields to be filled by caller */
 330     union {
 331         struct {
 332             int64_t sector;
 333             int nb_sectors;
 334             int flags;
 335             QEMUIOVector *qiov;
 336         };
 337         struct {
 338             int req;
 339             void *buf;
 340         };
 341     };
 342     BlockCompletionFunc *cb;
 343     void *opaque;
 344
 345     /* Filled by block layer */
 346     int error;
 347 } BlockRequest;
 348
 349 /* sg packet commands */
 350 int bdrv_ioctl(BlockDriverState *bs, unsigned long int req, void *buf);
 351 BlockAIOCB *bdrv_aio_ioctl(BlockDriverState *bs,
 352         unsigned long int req, void *buf,
 353         BlockCompletionFunc *cb, void *opaque);
 354
 355 /* Invalidate any cached metadata used by image formats */
 356 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp);
 357 void bdrv_invalidate_cache_all(Error **errp);
 358 int bdrv_inactivate_all(void);
 359
 360 /* Ensure contents are flushed to disk.  */
 361 int bdrv_flush(BlockDriverState *bs);
 362 int coroutine_fn bdrv_co_flush(BlockDriverState *bs);
 363 void bdrv_close_all(void);
 364 void bdrv_drain(BlockDriverState *bs);
 365 void coroutine_fn bdrv_co_drain(BlockDriverState *bs);
 366 void bdrv_drain_all(void);
 367
 368 int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors);
 369 int bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors);
 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 int bdrv_is_read_only(BlockDriverState *bs);
 388 int 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 int bdrv_is_encrypted(BlockDriverState *bs);
 416 int 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 int bdrv_query_missing_keys(void);
 420 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
 421                          void *opaque);
 422 const char *bdrv_get_node_name(const BlockDriverState *bs);
 423 const char *bdrv_get_device_name(const BlockDriverState *bs);
 424 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
 425 int bdrv_get_flags(BlockDriverState *bs);
 426 int bdrv_write_compressed(BlockDriverState *bs, int64_t sector_num,
 427                           const uint8_t *buf, int nb_sectors);
 428 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
 429 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs);
 430 void bdrv_round_to_clusters(BlockDriverState *bs,
 431                             int64_t sector_num, int nb_sectors,
 432                             int64_t *cluster_sector_num,
 433                             int *cluster_nb_sectors);
 434
 435 const char *bdrv_get_encrypted_filename(BlockDriverState *bs);
 436 void bdrv_get_backing_filename(BlockDriverState *bs,
 437                                char *filename, int filename_size);
 438 void bdrv_get_full_backing_filename(BlockDriverState *bs,
 439                                     char *dest, size_t sz, Error **errp);
 440 void bdrv_get_full_backing_filename_from_filename(const char *backed,
 441                                                   const char *backing,
 442                                                   char *dest, size_t sz,
 443                                                   Error **errp);
 444 int bdrv_is_snapshot(BlockDriverState *bs);
 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_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 453 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
 454                       int64_t pos, int size);
 455
 456 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
 457                       int64_t pos, int size);
 458
 459 void bdrv_img_create(const char *filename, const char *fmt,
 460                      const char *base_filename, const char *base_fmt,
 461                      char *options, uint64_t img_size, int flags,
 462                      Error **errp, bool quiet);
 463
 464 /* Returns the alignment in bytes that is required so that no bounce buffer
 465  * is required throughout the stack */
 466 size_t bdrv_min_mem_align(BlockDriverState *bs);
 467 /* Returns optimal alignment in bytes for bounce buffer */
 468 size_t bdrv_opt_mem_align(BlockDriverState *bs);
 469 void *qemu_blockalign(BlockDriverState *bs, size_t size);
 470 void *qemu_blockalign0(BlockDriverState *bs, size_t size);
 471 void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
 472 void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
 473 bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);
 474
 475 void bdrv_enable_copy_on_read(BlockDriverState *bs);
 476 void bdrv_disable_copy_on_read(BlockDriverState *bs);
 477
 478 void bdrv_ref(BlockDriverState *bs);
 479 void bdrv_unref(BlockDriverState *bs);
 480 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child);
 481 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
 482                              BlockDriverState *child_bs,
 483                              const char *child_name,
 484                              const BdrvChildRole *child_role);
 485
 486 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
 487 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);
 488 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason);
 489 void bdrv_op_block_all(BlockDriverState *bs, Error *reason);
 490 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason);
 491 bool bdrv_op_blocker_is_empty(BlockDriverState *bs);
 492
 493 #define BLKDBG_EVENT(child, evt) \
 494     do { \
 495         if (child) { \
 496             bdrv_debug_event(child->bs, evt); \
 497         } \
 498     } while (0)
 499
 500 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
 501
 502 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
 503                            const char *tag);
 504 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag);
 505 int bdrv_debug_resume(BlockDriverState *bs, const char *tag);
 506 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag);
 507
 508 /**
 509  * bdrv_get_aio_context:
 510  *
 511  * Returns: the currently bound #AioContext
 512  */
 513 AioContext *bdrv_get_aio_context(BlockDriverState *bs);
 514
 515 /**
 516  * bdrv_set_aio_context:
 517  *
 518  * Changes the #AioContext used for fd handlers, timers, and BHs by this
 519  * BlockDriverState and all its children.
 520  *
 521  * This function must be called with iothread lock held.
 522  */
 523 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context);
 524 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
 525 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
 526
 527 void bdrv_io_plug(BlockDriverState *bs);
 528 void bdrv_io_unplug(BlockDriverState *bs);
 529 void bdrv_io_unplugged_begin(BlockDriverState *bs);
 530 void bdrv_io_unplugged_end(BlockDriverState *bs);
 531
 532 /**
 533  * bdrv_drained_begin:
 534  *
 535  * Begin a quiesced section for exclusive access to the BDS, by disabling
 536  * external request sources including NBD server and device model. Note that
 537  * this doesn't block timers or coroutines from submitting more requests, which
 538  * means block_job_pause is still necessary.
 539  *
 540  * This function can be recursive.
 541  */
 542 void bdrv_drained_begin(BlockDriverState *bs);
 543
 544 /**
 545  * bdrv_drained_end:
 546  *
 547  * End a quiescent section started by bdrv_drained_begin().
 548  */
 549 void bdrv_drained_end(BlockDriverState *bs);
 550
 551 void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
 552                     Error **errp);
 553 void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
 554
 555 #endif