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