include/block/block.h

   1 #ifndef BLOCK_H
   2 #define BLOCK_H
   3
   4 #include "block/aio.h"
   5 #include "block/aio-wait.h"
   6 #include "qemu/iov.h"
   7 #include "qemu/coroutine.h"
   8 #include "block/accounting.h"
   9 #include "block/dirty-bitmap.h"
  10 #include "block/blockjob.h"
  11 #include "qemu/hbitmap.h"
  12
  13 /* block.c */
  14 typedef struct BlockDriver BlockDriver;
  15 typedef struct BdrvChild BdrvChild;
  16 typedef struct BdrvChildRole BdrvChildRole;
  17
  18 typedef struct BlockDriverInfo {
  19     /* in bytes, 0 if irrelevant */
  20     int cluster_size;
  21     /* offset at which the VM state can be saved (0 if not possible) */
  22     int64_t vm_state_offset;
  23     bool is_dirty;
  24     /*
  25      * True if unallocated blocks read back as zeroes. This is equivalent
  26      * to the LBPRZ flag in the SCSI logical block provisioning page.
  27      */
  28     bool unallocated_blocks_are_zero;
  29     /*
  30      * True if this block driver only supports compressed writes
  31      */
  32     bool needs_compressed_writes;
  33 } BlockDriverInfo;
  34
  35 typedef struct BlockFragInfo {
  36     uint64_t allocated_clusters;
  37     uint64_t total_clusters;
  38     uint64_t fragmented_clusters;
  39     uint64_t compressed_clusters;
  40 } BlockFragInfo;
  41
  42 typedef enum {
  43     BDRV_REQ_COPY_ON_READ       = 0x1,
  44     BDRV_REQ_ZERO_WRITE         = 0x2,
  45
  46     /*
  47      * The BDRV_REQ_MAY_UNMAP flag is used in write_zeroes requests to indicate
  48      * that the block driver should unmap (discard) blocks if it is guaranteed
  49      * that the result will read back as zeroes. The flag is only passed to the
  50      * driver if the block device is opened with BDRV_O_UNMAP.
  51      */
  52     BDRV_REQ_MAY_UNMAP          = 0x4,
  53
  54     BDRV_REQ_FUA                = 0x10,
  55     BDRV_REQ_WRITE_COMPRESSED   = 0x20,
  56
  57     /* Signifies that this write request will not change the visible disk
  58      * content. */
  59     BDRV_REQ_WRITE_UNCHANGED    = 0x40,
  60
  61     /*
  62      * BDRV_REQ_SERIALISING forces request serialisation for writes.
  63      * It is used to ensure that writes to the backing file of a backup process
  64      * target cannot race with a read of the backup target that defers to the
  65      * backing file.
  66      *
  67      * Note, that BDRV_REQ_SERIALISING is _not_ opposite in meaning to
  68      * BDRV_REQ_NO_SERIALISING. A more descriptive name for the latter might be
  69      * _DO_NOT_WAIT_FOR_SERIALISING, except that is too long.
  70      */
  71     BDRV_REQ_SERIALISING        = 0x80,
  72
  73     /* Execute the request only if the operation can be offloaded or otherwise
  74      * be executed efficiently, but return an error instead of using a slow
  75      * fallback. */
  76     BDRV_REQ_NO_FALLBACK        = 0x100,
  77
  78     /*
  79      * BDRV_REQ_PREFETCH may be used only together with BDRV_REQ_COPY_ON_READ
  80      * on read request and means that caller doesn't really need data to be
  81      * written to qiov parameter which may be NULL.
  82      */
  83     BDRV_REQ_PREFETCH  = 0x200,
  84     /* Mask of valid flags */
  85     BDRV_REQ_MASK               = 0x3ff,
  86 } BdrvRequestFlags;
  87
  88 typedef struct BlockSizes {
  89     uint32_t phys;
  90     uint32_t log;
  91 } BlockSizes;
  92
  93 typedef struct HDGeometry {
  94     uint32_t heads;
  95     uint32_t sectors;
  96     uint32_t cylinders;
  97 } HDGeometry;
  98
  99 #define BDRV_O_RDWR        0x0002
 100 #define BDRV_O_RESIZE      0x0004 /* request permission for resizing the node */
 101 #define BDRV_O_SNAPSHOT    0x0008 /* open the file read only and save writes in a snapshot */
 102 #define BDRV_O_TEMPORARY   0x0010 /* delete the file after use */
 103 #define BDRV_O_NOCACHE     0x0020 /* do not use the host page cache */
 104 #define BDRV_O_NATIVE_AIO  0x0080 /* use native AIO instead of the thread pool */
 105 #define BDRV_O_NO_BACKING  0x0100 /* don't open the backing file */
 106 #define BDRV_O_NO_FLUSH    0x0200 /* disable flushing on this disk */
 107 #define BDRV_O_COPY_ON_READ 0x0400 /* copy read backing sectors into image */
 108 #define BDRV_O_INACTIVE    0x0800  /* consistency hint for migration handoff */
 109 #define BDRV_O_CHECK       0x1000  /* open solely for consistency check */
 110 #define BDRV_O_ALLOW_RDWR  0x2000  /* allow reopen to change from r/o to r/w */
 111 #define BDRV_O_UNMAP       0x4000  /* execute guest UNMAP/TRIM operations */
 112 #define BDRV_O_PROTOCOL    0x8000  /* if no block driver is explicitly given:
 113                                       select an appropriate protocol driver,
 114                                       ignoring the format layer */
 115 #define BDRV_O_NO_IO       0x10000 /* don't initialize for I/O */
 116 #define BDRV_O_AUTO_RDONLY 0x20000 /* degrade to read-only if opening read-write fails */
 117 #define BDRV_O_IO_URING    0x40000 /* use io_uring instead of the thread pool */
 118
 119 #define BDRV_O_CACHE_MASK  (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH)
 120
 121
 122 /* Option names of options parsed by the block layer */
 123
 124 #define BDRV_OPT_CACHE_WB       "cache.writeback"
 125 #define BDRV_OPT_CACHE_DIRECT   "cache.direct"
 126 #define BDRV_OPT_CACHE_NO_FLUSH "cache.no-flush"
 127 #define BDRV_OPT_READ_ONLY      "read-only"
 128 #define BDRV_OPT_AUTO_READ_ONLY "auto-read-only"
 129 #define BDRV_OPT_DISCARD        "discard"
 130 #define BDRV_OPT_FORCE_SHARE    "force-share"
 131
 132
 133 #define BDRV_SECTOR_BITS   9
 134 #define BDRV_SECTOR_SIZE   (1ULL << BDRV_SECTOR_BITS)
 135
 136 #define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \
 137                                      INT_MAX >> BDRV_SECTOR_BITS)
 138 #define BDRV_REQUEST_MAX_BYTES (BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS)
 139
 140 /*
 141  * Allocation status flags for bdrv_block_status() and friends.
 142  *
 143  * Public flags:
 144  * BDRV_BLOCK_DATA: allocation for data at offset is tied to this layer
 145  * BDRV_BLOCK_ZERO: offset reads as zero
 146  * BDRV_BLOCK_OFFSET_VALID: an associated offset exists for accessing raw data
 147  * BDRV_BLOCK_ALLOCATED: the content of the block is determined by this
 148  *                       layer rather than any backing, set by block layer
 149  * BDRV_BLOCK_EOF: the returned pnum covers through end of file for this
 150  *                 layer, set by block layer
 151  *
 152  * Internal flags:
 153  * BDRV_BLOCK_RAW: for use by passthrough drivers, such as raw, to request
 154  *                 that the block layer recompute the answer from the returned
 155  *                 BDS; must be accompanied by just BDRV_BLOCK_OFFSET_VALID.
 156  * BDRV_BLOCK_RECURSE: request that the block layer will recursively search for
 157  *                     zeroes in file child of current block node inside
 158  *                     returned region. Only valid together with both
 159  *                     BDRV_BLOCK_DATA and BDRV_BLOCK_OFFSET_VALID. Should not
 160  *                     appear with BDRV_BLOCK_ZERO.
 161  *
 162  * If BDRV_BLOCK_OFFSET_VALID is set, the map parameter represents the
 163  * host offset within the returned BDS that is allocated for the
 164  * corresponding raw guest data.  However, whether that offset
 165  * actually contains data also depends on BDRV_BLOCK_DATA, as follows:
 166  *
 167  * DATA ZERO OFFSET_VALID
 168  *  t    t        t       sectors read as zero, returned file is zero at offset
 169  *  t    f        t       sectors read as valid from file at offset
 170  *  f    t        t       sectors preallocated, read as zero, returned file not
 171  *                        necessarily zero at offset
 172  *  f    f        t       sectors preallocated but read from backing_hd,
 173  *                        returned file contains garbage at offset
 174  *  t    t        f       sectors preallocated, read as zero, unknown offset
 175  *  t    f        f       sectors read from unknown file or offset
 176  *  f    t        f       not allocated or unknown offset, read as zero
 177  *  f    f        f       not allocated or unknown offset, read from backing_hd
 178  */
 179 #define BDRV_BLOCK_DATA         0x01
 180 #define BDRV_BLOCK_ZERO         0x02
 181 #define BDRV_BLOCK_OFFSET_VALID 0x04
 182 #define BDRV_BLOCK_RAW          0x08
 183 #define BDRV_BLOCK_ALLOCATED    0x10
 184 #define BDRV_BLOCK_EOF          0x20
 185 #define BDRV_BLOCK_RECURSE      0x40
 186
 187 typedef QTAILQ_HEAD(BlockReopenQueue, BlockReopenQueueEntry) BlockReopenQueue;
 188
 189 typedef struct BDRVReopenState {
 190     BlockDriverState *bs;
 191     int flags;
 192     BlockdevDetectZeroesOptions detect_zeroes;
 193     bool backing_missing;
 194     bool replace_backing_bs;  /* new_backing_bs is ignored if this is false */
 195     BlockDriverState *new_backing_bs; /* If NULL then detach the current bs */
 196     uint64_t perm, shared_perm;
 197     QDict *options;
 198     QDict *explicit_options;
 199     void *opaque;
 200 } BDRVReopenState;
 201
 202 /*
 203  * Block operation types
 204  */
 205 typedef enum BlockOpType {
 206     BLOCK_OP_TYPE_BACKUP_SOURCE,
 207     BLOCK_OP_TYPE_BACKUP_TARGET,
 208     BLOCK_OP_TYPE_CHANGE,
 209     BLOCK_OP_TYPE_COMMIT_SOURCE,
 210     BLOCK_OP_TYPE_COMMIT_TARGET,
 211     BLOCK_OP_TYPE_DATAPLANE,
 212     BLOCK_OP_TYPE_DRIVE_DEL,
 213     BLOCK_OP_TYPE_EJECT,
 214     BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
 215     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT,
 216     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
 217     BLOCK_OP_TYPE_MIRROR_SOURCE,
 218     BLOCK_OP_TYPE_MIRROR_TARGET,
 219     BLOCK_OP_TYPE_RESIZE,
 220     BLOCK_OP_TYPE_STREAM,
 221     BLOCK_OP_TYPE_REPLACE,
 222     BLOCK_OP_TYPE_MAX,
 223 } BlockOpType;
 224
 225 /* Block node permission constants */
 226 enum {
 227     /**
 228      * A user that has the "permission" of consistent reads is guaranteed that
 229      * their view of the contents of the block device is complete and
 230      * self-consistent, representing the contents of a disk at a specific
 231      * point.
 232      *
 233      * For most block devices (including their backing files) this is true, but
 234      * the property cannot be maintained in a few situations like for
 235      * intermediate nodes of a commit block job.
 236      */
 237     BLK_PERM_CONSISTENT_READ    = 0x01,
 238
 239     /** This permission is required to change the visible disk contents. */
 240     BLK_PERM_WRITE              = 0x02,
 241
 242     /**
 243      * This permission (which is weaker than BLK_PERM_WRITE) is both enough and
 244      * required for writes to the block node when the caller promises that
 245      * the visible disk content doesn't change.
 246      *
 247      * As the BLK_PERM_WRITE permission is strictly stronger, either is
 248      * sufficient to perform an unchanging write.
 249      */
 250     BLK_PERM_WRITE_UNCHANGED    = 0x04,
 251
 252     /** This permission is required to change the size of a block node. */
 253     BLK_PERM_RESIZE             = 0x08,
 254
 255     /**
 256      * This permission is required to change the node that this BdrvChild
 257      * points to.
 258      */
 259     BLK_PERM_GRAPH_MOD          = 0x10,
 260
 261     BLK_PERM_ALL                = 0x1f,
 262
 263     DEFAULT_PERM_PASSTHROUGH    = BLK_PERM_CONSISTENT_READ
 264                                  | BLK_PERM_WRITE
 265                                  | BLK_PERM_WRITE_UNCHANGED
 266                                  | BLK_PERM_RESIZE,
 267
 268     DEFAULT_PERM_UNCHANGED      = BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH,
 269 };
 270
 271 char *bdrv_perm_names(uint64_t perm);
 272 uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm);
 273
 274 /* disk I/O throttling */
 275 void bdrv_init(void);
 276 void bdrv_init_with_whitelist(void);
 277 bool bdrv_uses_whitelist(void);
 278 int bdrv_is_whitelisted(BlockDriver *drv, bool read_only);
 279 BlockDriver *bdrv_find_protocol(const char *filename,
 280                                 bool allow_protocol_prefix,
 281                                 Error **errp);
 282 BlockDriver *bdrv_find_format(const char *format_name);
 283 int bdrv_create(BlockDriver *drv, const char* filename,
 284                 QemuOpts *opts, Error **errp);
 285 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp);
 286 BlockDriverState *bdrv_new(void);
 287 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
 288                  Error **errp);
 289 void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
 290                        Error **errp);
 291
 292 int bdrv_parse_aio(const char *mode, int *flags);
 293 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough);
 294 int bdrv_parse_discard_flags(const char *mode, int *flags);
 295 BdrvChild *bdrv_open_child(const char *filename,
 296                            QDict *options, const char *bdref_key,
 297                            BlockDriverState* parent,
 298                            const BdrvChildRole *child_role,
 299                            bool allow_none, Error **errp);
 300 BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp);
 301 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
 302                          Error **errp);
 303 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
 304                            const char *bdref_key, Error **errp);
 305 BlockDriverState *bdrv_open(const char *filename, const char *reference,
 306                             QDict *options, int flags, Error **errp);
 307 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
 308                                        int flags, Error **errp);
 309 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
 310                                     BlockDriverState *bs, QDict *options,
 311                                     bool keep_old_opts);
 312 int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp);
 313 int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
 314                               Error **errp);
 315 int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
 316                         BlockReopenQueue *queue, Error **errp);
 317 void bdrv_reopen_commit(BDRVReopenState *reopen_state);
 318 void bdrv_reopen_abort(BDRVReopenState *reopen_state);
 319 int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
 320                        int bytes, BdrvRequestFlags flags);
 321 int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
 322 int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes);
 323 int bdrv_preadv(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
 324 int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes);
 325 int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
 326 int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
 327                      const void *buf, int count);
 328 /*
 329  * Efficiently zero a region of the disk image.  Note that this is a regular
 330  * I/O request like read or write and should have a reasonable size.  This
 331  * function is not suitable for zeroing the entire image in a single request
 332  * because it may allocate memory for the entire region.
 333  */
 334 int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
 335                                        int bytes, BdrvRequestFlags flags);
 336 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
 337     const char *backing_file);
 338 void bdrv_refresh_filename(BlockDriverState *bs);
 339
 340 int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact,
 341                                   PreallocMode prealloc, Error **errp);
 342 int bdrv_truncate(BdrvChild *child, int64_t offset, bool exact,
 343                   PreallocMode prealloc, Error **errp);
 344
 345 int64_t bdrv_nb_sectors(BlockDriverState *bs);
 346 int64_t bdrv_getlength(BlockDriverState *bs);
 347 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
 348 BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
 349                                BlockDriverState *in_bs, Error **errp);
 350 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
 351 void bdrv_refresh_limits(BlockDriverState *bs, Error **errp);
 352 int bdrv_commit(BlockDriverState *bs);
 353 int bdrv_change_backing_file(BlockDriverState *bs,
 354     const char *backing_file, const char *backing_fmt);
 355 void bdrv_register(BlockDriver *bdrv);
 356 int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
 357                            const char *backing_file_str);
 358 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
 359                                     BlockDriverState *bs);
 360 BlockDriverState *bdrv_find_base(BlockDriverState *bs);
 361 bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base,
 362                                   Error **errp);
 363 int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base,
 364                               Error **errp);
 365 void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base);
 366
 367
 368 typedef struct BdrvCheckResult {
 369     int corruptions;
 370     int leaks;
 371     int check_errors;
 372     int corruptions_fixed;
 373     int leaks_fixed;
 374     int64_t image_end_offset;
 375     BlockFragInfo bfi;
 376 } BdrvCheckResult;
 377
 378 typedef enum {
 379     BDRV_FIX_LEAKS    = 1,
 380     BDRV_FIX_ERRORS   = 2,
 381 } BdrvCheckMode;
 382
 383 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
 384
 385 /* The units of offset and total_work_size may be chosen arbitrarily by the
 386  * block driver; total_work_size may change during the course of the amendment
 387  * operation */
 388 typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
 389                                       int64_t total_work_size, void *opaque);
 390 int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
 391                        BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
 392                        Error **errp);
 393
 394 /* check if a named node can be replaced when doing drive-mirror */
 395 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
 396                                         const char *node_name, Error **errp);
 397
 398 /* async block I/O */
 399 void bdrv_aio_cancel(BlockAIOCB *acb);
 400 void bdrv_aio_cancel_async(BlockAIOCB *acb);
 401
 402 /* sg packet commands */
 403 int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf);
 404
 405 /* Invalidate any cached metadata used by image formats */
 406 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp);
 407 void bdrv_invalidate_cache_all(Error **errp);
 408 int bdrv_inactivate_all(void);
 409
 410 /* Ensure contents are flushed to disk.  */
 411 int bdrv_flush(BlockDriverState *bs);
 412 int coroutine_fn bdrv_co_flush(BlockDriverState *bs);
 413 int bdrv_flush_all(void);
 414 void bdrv_close_all(void);
 415 void bdrv_drain(BlockDriverState *bs);
 416 void coroutine_fn bdrv_co_drain(BlockDriverState *bs);
 417 void bdrv_drain_all_begin(void);
 418 void bdrv_drain_all_end(void);
 419 void bdrv_drain_all(void);
 420
 421 #define BDRV_POLL_WHILE(bs, cond) ({                       \
 422     BlockDriverState *bs_ = (bs);                          \
 423     AIO_WAIT_WHILE(bdrv_get_aio_context(bs_),              \
 424                    cond); })
 425
 426 int bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
 427 int bdrv_co_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
 428 int bdrv_has_zero_init_1(BlockDriverState *bs);
 429 int bdrv_has_zero_init(BlockDriverState *bs);
 430 int bdrv_has_zero_init_truncate(BlockDriverState *bs);
 431 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs);
 432 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
 433 int bdrv_block_status(BlockDriverState *bs, int64_t offset,
 434                       int64_t bytes, int64_t *pnum, int64_t *map,
 435                       BlockDriverState **file);
 436 int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
 437                             int64_t offset, int64_t bytes, int64_t *pnum,
 438                             int64_t *map, BlockDriverState **file);
 439 int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
 440                       int64_t *pnum);
 441 int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
 442                             bool include_base, int64_t offset, int64_t bytes,
 443                             int64_t *pnum);
 444
 445 bool bdrv_is_read_only(BlockDriverState *bs);
 446 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
 447                            bool ignore_allow_rdw, Error **errp);
 448 int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg,
 449                               Error **errp);
 450 bool bdrv_is_writable(BlockDriverState *bs);
 451 bool bdrv_is_sg(BlockDriverState *bs);
 452 bool bdrv_is_inserted(BlockDriverState *bs);
 453 void bdrv_lock_medium(BlockDriverState *bs, bool locked);
 454 void bdrv_eject(BlockDriverState *bs, bool eject_flag);
 455 const char *bdrv_get_format_name(BlockDriverState *bs);
 456 BlockDriverState *bdrv_find_node(const char *node_name);
 457 BlockDeviceInfoList *bdrv_named_nodes_list(bool flat, Error **errp);
 458 XDbgBlockGraph *bdrv_get_xdbg_block_graph(Error **errp);
 459 BlockDriverState *bdrv_lookup_bs(const char *device,
 460                                  const char *node_name,
 461                                  Error **errp);
 462 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
 463 BlockDriverState *bdrv_next_node(BlockDriverState *bs);
 464 BlockDriverState *bdrv_next_all_states(BlockDriverState *bs);
 465
 466 typedef struct BdrvNextIterator {
 467     enum {
 468         BDRV_NEXT_BACKEND_ROOTS,
 469         BDRV_NEXT_MONITOR_OWNED,
 470     } phase;
 471     BlockBackend *blk;
 472     BlockDriverState *bs;
 473 } BdrvNextIterator;
 474
 475 BlockDriverState *bdrv_first(BdrvNextIterator *it);
 476 BlockDriverState *bdrv_next(BdrvNextIterator *it);
 477 void bdrv_next_cleanup(BdrvNextIterator *it);
 478
 479 BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs);
 480 bool bdrv_is_encrypted(BlockDriverState *bs);
 481 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
 482                          void *opaque, bool read_only);
 483 const char *bdrv_get_node_name(const BlockDriverState *bs);
 484 const char *bdrv_get_device_name(const BlockDriverState *bs);
 485 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
 486 int bdrv_get_flags(BlockDriverState *bs);
 487 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
 488 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs,
 489                                           Error **errp);
 490 BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs);
 491 void bdrv_round_to_clusters(BlockDriverState *bs,
 492                             int64_t offset, int64_t bytes,
 493                             int64_t *cluster_offset,
 494                             int64_t *cluster_bytes);
 495
 496 void bdrv_get_backing_filename(BlockDriverState *bs,
 497                                char *filename, int filename_size);
 498 char *bdrv_get_full_backing_filename(BlockDriverState *bs, Error **errp);
 499 char *bdrv_get_full_backing_filename_from_filename(const char *backed,
 500                                                    const char *backing,
 501                                                    Error **errp);
 502 char *bdrv_dirname(BlockDriverState *bs, Error **errp);
 503
 504 int path_has_protocol(const char *path);
 505 int path_is_absolute(const char *path);
 506 char *path_combine(const char *base_path, const char *filename);
 507
 508 int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 509 int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 510 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
 511                       int64_t pos, int size);
 512
 513 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
 514                       int64_t pos, int size);
 515
 516 void bdrv_img_create(const char *filename, const char *fmt,
 517                      const char *base_filename, const char *base_fmt,
 518                      char *options, uint64_t img_size, int flags,
 519                      bool quiet, Error **errp);
 520
 521 /* Returns the alignment in bytes that is required so that no bounce buffer
 522  * is required throughout the stack */
 523 size_t bdrv_min_mem_align(BlockDriverState *bs);
 524 /* Returns optimal alignment in bytes for bounce buffer */
 525 size_t bdrv_opt_mem_align(BlockDriverState *bs);
 526 void *qemu_blockalign(BlockDriverState *bs, size_t size);
 527 void *qemu_blockalign0(BlockDriverState *bs, size_t size);
 528 void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
 529 void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
 530 bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);
 531
 532 void bdrv_enable_copy_on_read(BlockDriverState *bs);
 533 void bdrv_disable_copy_on_read(BlockDriverState *bs);
 534
 535 void bdrv_ref(BlockDriverState *bs);
 536 void bdrv_unref(BlockDriverState *bs);
 537 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child);
 538 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
 539                              BlockDriverState *child_bs,
 540                              const char *child_name,
 541                              const BdrvChildRole *child_role,
 542                              Error **errp);
 543
 544 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
 545 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);
 546 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason);
 547 void bdrv_op_block_all(BlockDriverState *bs, Error *reason);
 548 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason);
 549 bool bdrv_op_blocker_is_empty(BlockDriverState *bs);
 550
 551 #define BLKDBG_EVENT(child, evt) \
 552     do { \
 553         if (child) { \
 554             bdrv_debug_event(child->bs, evt); \
 555         } \
 556     } while (0)
 557
 558 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
 559
 560 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
 561                            const char *tag);
 562 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag);
 563 int bdrv_debug_resume(BlockDriverState *bs, const char *tag);
 564 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag);
 565
 566 /**
 567  * bdrv_get_aio_context:
 568  *
 569  * Returns: the currently bound #AioContext
 570  */
 571 AioContext *bdrv_get_aio_context(BlockDriverState *bs);
 572
 573 /**
 574  * Transfer control to @co in the aio context of @bs
 575  */
 576 void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co);
 577
 578 void bdrv_set_aio_context_ignore(BlockDriverState *bs,
 579                                  AioContext *new_context, GSList **ignore);
 580 int bdrv_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
 581                              Error **errp);
 582 int bdrv_child_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
 583                                    BdrvChild *ignore_child, Error **errp);
 584 bool bdrv_child_can_set_aio_context(BdrvChild *c, AioContext *ctx,
 585                                     GSList **ignore, Error **errp);
 586 bool bdrv_can_set_aio_context(BlockDriverState *bs, AioContext *ctx,
 587                               GSList **ignore, Error **errp);
 588 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
 589 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
 590
 591 void bdrv_io_plug(BlockDriverState *bs);
 592 void bdrv_io_unplug(BlockDriverState *bs);
 593
 594 /**
 595  * bdrv_parent_drained_begin_single:
 596  *
 597  * Begin a quiesced section for the parent of @c. If @poll is true, wait for
 598  * any pending activity to cease.
 599  */
 600 void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll);
 601
 602 /**
 603  * bdrv_parent_drained_end_single:
 604  *
 605  * End a quiesced section for the parent of @c.
 606  *
 607  * This polls @bs's AioContext until all scheduled sub-drained_ends
 608  * have settled, which may result in graph changes.
 609  */
 610 void bdrv_parent_drained_end_single(BdrvChild *c);
 611
 612 /**
 613  * bdrv_drain_poll:
 614  *
 615  * Poll for pending requests in @bs, its parents (except for @ignore_parent),
 616  * and if @recursive is true its children as well (used for subtree drain).
 617  *
 618  * If @ignore_bds_parents is true, parents that are BlockDriverStates must
 619  * ignore the drain request because they will be drained separately (used for
 620  * drain_all).
 621  *
 622  * This is part of bdrv_drained_begin.
 623  */
 624 bool bdrv_drain_poll(BlockDriverState *bs, bool recursive,
 625                      BdrvChild *ignore_parent, bool ignore_bds_parents);
 626
 627 /**
 628  * bdrv_drained_begin:
 629  *
 630  * Begin a quiesced section for exclusive access to the BDS, by disabling
 631  * external request sources including NBD server and device model. Note that
 632  * this doesn't block timers or coroutines from submitting more requests, which
 633  * means block_job_pause is still necessary.
 634  *
 635  * This function can be recursive.
 636  */
 637 void bdrv_drained_begin(BlockDriverState *bs);
 638
 639 /**
 640  * bdrv_do_drained_begin_quiesce:
 641  *
 642  * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already
 643  * running requests to complete.
 644  */
 645 void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,
 646                                    BdrvChild *parent, bool ignore_bds_parents);
 647
 648 /**
 649  * Like bdrv_drained_begin, but recursively begins a quiesced section for
 650  * exclusive access to all child nodes as well.
 651  */
 652 void bdrv_subtree_drained_begin(BlockDriverState *bs);
 653
 654 /**
 655  * bdrv_drained_end:
 656  *
 657  * End a quiescent section started by bdrv_drained_begin().
 658  *
 659  * This polls @bs's AioContext until all scheduled sub-drained_ends
 660  * have settled.  On one hand, that may result in graph changes.  On
 661  * the other, this requires that the caller either runs in the main
 662  * loop; or that all involved nodes (@bs and all of its parents) are
 663  * in the caller's AioContext.
 664  */
 665 void bdrv_drained_end(BlockDriverState *bs);
 666
 667 /**
 668  * bdrv_drained_end_no_poll:
 669  *
 670  * Same as bdrv_drained_end(), but do not poll for the subgraph to
 671  * actually become unquiesced.  Therefore, no graph changes will occur
 672  * with this function.
 673  *
 674  * *drained_end_counter is incremented for every background operation
 675  * that is scheduled, and will be decremented for every operation once
 676  * it settles.  The caller must poll until it reaches 0.  The counter
 677  * should be accessed using atomic operations only.
 678  */
 679 void bdrv_drained_end_no_poll(BlockDriverState *bs, int *drained_end_counter);
 680
 681 /**
 682  * End a quiescent section started by bdrv_subtree_drained_begin().
 683  */
 684 void bdrv_subtree_drained_end(BlockDriverState *bs);
 685
 686 void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
 687                     Error **errp);
 688 void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
 689
 690 bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
 691                                      uint32_t granularity, Error **errp);
 692 /**
 693  *
 694  * bdrv_register_buf/bdrv_unregister_buf:
 695  *
 696  * Register/unregister a buffer for I/O. For example, VFIO drivers are
 697  * interested to know the memory areas that would later be used for I/O, so
 698  * that they can prepare IOMMU mapping etc., to get better performance.
 699  */
 700 void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size);
 701 void bdrv_unregister_buf(BlockDriverState *bs, void *host);
 702
 703 /**
 704  *
 705  * bdrv_co_copy_range:
 706  *
 707  * Do offloaded copy between two children. If the operation is not implemented
 708  * by the driver, or if the backend storage doesn't support it, a negative
 709  * error code will be returned.
 710  *
 711  * Note: block layer doesn't emulate or fallback to a bounce buffer approach
 712  * because usually the caller shouldn't attempt offloaded copy any more (e.g.
 713  * calling copy_file_range(2)) after the first error, thus it should fall back
 714  * to a read+write path in the caller level.
 715  *
 716  * @src: Source child to copy data from
 717  * @src_offset: offset in @src image to read data
 718  * @dst: Destination child to copy data to
 719  * @dst_offset: offset in @dst image to write data
 720  * @bytes: number of bytes to copy
 721  * @flags: request flags. Supported flags:
 722  *         BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero
 723  *                               write on @dst as if bdrv_co_pwrite_zeroes is
 724  *                               called. Used to simplify caller code, or
 725  *                               during BlockDriver.bdrv_co_copy_range_from()
 726  *                               recursion.
 727  *         BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping
 728  *                                   requests currently in flight.
 729  *
 730  * Returns: 0 if succeeded; negative error code if failed.
 731  **/
 732 int coroutine_fn bdrv_co_copy_range(BdrvChild *src, uint64_t src_offset,
 733                                     BdrvChild *dst, uint64_t dst_offset,
 734                                     uint64_t bytes, BdrvRequestFlags read_flags,
 735                                     BdrvRequestFlags write_flags);
 736 #endif