include/block/block_int.h

   1 /*
   2  * QEMU System Emulator block driver
   3  *
   4  * Copyright (c) 2003 Fabrice Bellard
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #ifndef BLOCK_INT_H
  25 #define BLOCK_INT_H
  26
  27 #include "block/accounting.h"
  28 #include "block/block.h"
  29 #include "qemu/option.h"
  30 #include "qemu/queue.h"
  31 #include "block/coroutine.h"
  32 #include "qemu/timer.h"
  33 #include "qapi-types.h"
  34 #include "qapi/qmp/qerror.h"
  35 #include "monitor/monitor.h"
  36 #include "qemu/hbitmap.h"
  37 #include "block/snapshot.h"
  38 #include "qemu/main-loop.h"
  39 #include "qemu/throttle.h"
  40
  41 #define BLOCK_FLAG_ENCRYPT          1
  42 #define BLOCK_FLAG_COMPAT6          4
  43 #define BLOCK_FLAG_LAZY_REFCOUNTS   8
  44
  45 #define BLOCK_OPT_SIZE              "size"
  46 #define BLOCK_OPT_ENCRYPT           "encryption"
  47 #define BLOCK_OPT_COMPAT6           "compat6"
  48 #define BLOCK_OPT_BACKING_FILE      "backing_file"
  49 #define BLOCK_OPT_BACKING_FMT       "backing_fmt"
  50 #define BLOCK_OPT_CLUSTER_SIZE      "cluster_size"
  51 #define BLOCK_OPT_TABLE_SIZE        "table_size"
  52 #define BLOCK_OPT_PREALLOC          "preallocation"
  53 #define BLOCK_OPT_SUBFMT            "subformat"
  54 #define BLOCK_OPT_COMPAT_LEVEL      "compat"
  55 #define BLOCK_OPT_LAZY_REFCOUNTS    "lazy_refcounts"
  56 #define BLOCK_OPT_ADAPTER_TYPE      "adapter_type"
  57 #define BLOCK_OPT_REDUNDANCY        "redundancy"
  58 #define BLOCK_OPT_NOCOW             "nocow"
  59
  60 typedef struct BdrvTrackedRequest {
  61     BlockDriverState *bs;
  62     int64_t offset;
  63     unsigned int bytes;
  64     bool is_write;
  65
  66     bool serialising;
  67     int64_t overlap_offset;
  68     unsigned int overlap_bytes;
  69
  70     QLIST_ENTRY(BdrvTrackedRequest) list;
  71     Coroutine *co; /* owner, used for deadlock detection */
  72     CoQueue wait_queue; /* coroutines blocked on this request */
  73
  74     struct BdrvTrackedRequest *waiting_for;
  75 } BdrvTrackedRequest;
  76
  77 struct BlockDriver {
  78     const char *format_name;
  79     int instance_size;
  80
  81     /* set to true if the BlockDriver is a block filter */
  82     bool is_filter;
  83     /* for snapshots block filter like Quorum can implement the
  84      * following recursive callback.
  85      * It's purpose is to recurse on the filter children while calling
  86      * bdrv_recurse_is_first_non_filter on them.
  87      * For a sample implementation look in the future Quorum block filter.
  88      */
  89     bool (*bdrv_recurse_is_first_non_filter)(BlockDriverState *bs,
  90                                              BlockDriverState *candidate);
  91
  92     int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename);
  93     int (*bdrv_probe_device)(const char *filename);
  94
  95     /* Any driver implementing this callback is expected to be able to handle
  96      * NULL file names in its .bdrv_open() implementation */
  97     void (*bdrv_parse_filename)(const char *filename, QDict *options, Error **errp);
  98     /* Drivers not implementing bdrv_parse_filename nor bdrv_open should have
  99      * this field set to true, except ones that are defined only by their
 100      * child's bs.
 101      * An example of the last type will be the quorum block driver.
 102      */
 103     bool bdrv_needs_filename;
 104
 105     /* Set if a driver can support backing files */
 106     bool supports_backing;
 107
 108     /* For handling image reopen for split or non-split files */
 109     int (*bdrv_reopen_prepare)(BDRVReopenState *reopen_state,
 110                                BlockReopenQueue *queue, Error **errp);
 111     void (*bdrv_reopen_commit)(BDRVReopenState *reopen_state);
 112     void (*bdrv_reopen_abort)(BDRVReopenState *reopen_state);
 113
 114     int (*bdrv_open)(BlockDriverState *bs, QDict *options, int flags,
 115                      Error **errp);
 116     int (*bdrv_file_open)(BlockDriverState *bs, QDict *options, int flags,
 117                           Error **errp);
 118     int (*bdrv_read)(BlockDriverState *bs, int64_t sector_num,
 119                      uint8_t *buf, int nb_sectors);
 120     int (*bdrv_write)(BlockDriverState *bs, int64_t sector_num,
 121                       const uint8_t *buf, int nb_sectors);
 122     void (*bdrv_close)(BlockDriverState *bs);
 123     void (*bdrv_rebind)(BlockDriverState *bs);
 124     int (*bdrv_create)(const char *filename, QemuOpts *opts, Error **errp);
 125     int (*bdrv_set_key)(BlockDriverState *bs, const char *key);
 126     int (*bdrv_make_empty)(BlockDriverState *bs);
 127
 128     void (*bdrv_refresh_filename)(BlockDriverState *bs);
 129
 130     /* aio */
 131     BlockDriverAIOCB *(*bdrv_aio_readv)(BlockDriverState *bs,
 132         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 133         BlockDriverCompletionFunc *cb, void *opaque);
 134     BlockDriverAIOCB *(*bdrv_aio_writev)(BlockDriverState *bs,
 135         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 136         BlockDriverCompletionFunc *cb, void *opaque);
 137     BlockDriverAIOCB *(*bdrv_aio_flush)(BlockDriverState *bs,
 138         BlockDriverCompletionFunc *cb, void *opaque);
 139     BlockDriverAIOCB *(*bdrv_aio_discard)(BlockDriverState *bs,
 140         int64_t sector_num, int nb_sectors,
 141         BlockDriverCompletionFunc *cb, void *opaque);
 142
 143     int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs,
 144         int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
 145     int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs,
 146         int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
 147     /*
 148      * Efficiently zero a region of the disk image.  Typically an image format
 149      * would use a compact metadata representation to implement this.  This
 150      * function pointer may be NULL and .bdrv_co_writev() will be called
 151      * instead.
 152      */
 153     int coroutine_fn (*bdrv_co_write_zeroes)(BlockDriverState *bs,
 154         int64_t sector_num, int nb_sectors, BdrvRequestFlags flags);
 155     int coroutine_fn (*bdrv_co_discard)(BlockDriverState *bs,
 156         int64_t sector_num, int nb_sectors);
 157     int64_t coroutine_fn (*bdrv_co_get_block_status)(BlockDriverState *bs,
 158         int64_t sector_num, int nb_sectors, int *pnum);
 159
 160     /*
 161      * Invalidate any cached meta-data.
 162      */
 163     void (*bdrv_invalidate_cache)(BlockDriverState *bs, Error **errp);
 164
 165     /*
 166      * Flushes all data that was already written to the OS all the way down to
 167      * the disk (for example raw-posix calls fsync()).
 168      */
 169     int coroutine_fn (*bdrv_co_flush_to_disk)(BlockDriverState *bs);
 170
 171     /*
 172      * Flushes all internal caches to the OS. The data may still sit in a
 173      * writeback cache of the host OS, but it will survive a crash of the qemu
 174      * process.
 175      */
 176     int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs);
 177
 178     const char *protocol_name;
 179     int (*bdrv_truncate)(BlockDriverState *bs, int64_t offset);
 180
 181     int64_t (*bdrv_getlength)(BlockDriverState *bs);
 182     bool has_variable_length;
 183     int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs);
 184
 185     int (*bdrv_write_compressed)(BlockDriverState *bs, int64_t sector_num,
 186                                  const uint8_t *buf, int nb_sectors);
 187
 188     int (*bdrv_snapshot_create)(BlockDriverState *bs,
 189                                 QEMUSnapshotInfo *sn_info);
 190     int (*bdrv_snapshot_goto)(BlockDriverState *bs,
 191                               const char *snapshot_id);
 192     int (*bdrv_snapshot_delete)(BlockDriverState *bs,
 193                                 const char *snapshot_id,
 194                                 const char *name,
 195                                 Error **errp);
 196     int (*bdrv_snapshot_list)(BlockDriverState *bs,
 197                               QEMUSnapshotInfo **psn_info);
 198     int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs,
 199                                   const char *snapshot_id,
 200                                   const char *name,
 201                                   Error **errp);
 202     int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi);
 203     ImageInfoSpecific *(*bdrv_get_specific_info)(BlockDriverState *bs);
 204
 205     int (*bdrv_save_vmstate)(BlockDriverState *bs, QEMUIOVector *qiov,
 206                              int64_t pos);
 207     int (*bdrv_load_vmstate)(BlockDriverState *bs, uint8_t *buf,
 208                              int64_t pos, int size);
 209
 210     int (*bdrv_change_backing_file)(BlockDriverState *bs,
 211         const char *backing_file, const char *backing_fmt);
 212
 213     /* removable device specific */
 214     int (*bdrv_is_inserted)(BlockDriverState *bs);
 215     int (*bdrv_media_changed)(BlockDriverState *bs);
 216     void (*bdrv_eject)(BlockDriverState *bs, bool eject_flag);
 217     void (*bdrv_lock_medium)(BlockDriverState *bs, bool locked);
 218
 219     /* to control generic scsi devices */
 220     int (*bdrv_ioctl)(BlockDriverState *bs, unsigned long int req, void *buf);
 221     BlockDriverAIOCB *(*bdrv_aio_ioctl)(BlockDriverState *bs,
 222         unsigned long int req, void *buf,
 223         BlockDriverCompletionFunc *cb, void *opaque);
 224
 225     /* List of options for creating images, terminated by name == NULL */
 226     QemuOptsList *create_opts;
 227
 228     /*
 229      * Returns 0 for completed check, -errno for internal errors.
 230      * The check results are stored in result.
 231      */
 232     int (*bdrv_check)(BlockDriverState* bs, BdrvCheckResult *result,
 233         BdrvCheckMode fix);
 234
 235     int (*bdrv_amend_options)(BlockDriverState *bs, QemuOpts *opts);
 236
 237     void (*bdrv_debug_event)(BlockDriverState *bs, BlkDebugEvent event);
 238
 239     /* TODO Better pass a option string/QDict/QemuOpts to add any rule? */
 240     int (*bdrv_debug_breakpoint)(BlockDriverState *bs, const char *event,
 241         const char *tag);
 242     int (*bdrv_debug_remove_breakpoint)(BlockDriverState *bs,
 243         const char *tag);
 244     int (*bdrv_debug_resume)(BlockDriverState *bs, const char *tag);
 245     bool (*bdrv_debug_is_suspended)(BlockDriverState *bs, const char *tag);
 246
 247     void (*bdrv_refresh_limits)(BlockDriverState *bs, Error **errp);
 248
 249     /*
 250      * Returns 1 if newly created images are guaranteed to contain only
 251      * zeros, 0 otherwise.
 252      */
 253     int (*bdrv_has_zero_init)(BlockDriverState *bs);
 254
 255     /* Remove fd handlers, timers, and other event loop callbacks so the event
 256      * loop is no longer in use.  Called with no in-flight requests and in
 257      * depth-first traversal order with parents before child nodes.
 258      */
 259     void (*bdrv_detach_aio_context)(BlockDriverState *bs);
 260
 261     /* Add fd handlers, timers, and other event loop callbacks so I/O requests
 262      * can be processed again.  Called with no in-flight requests and in
 263      * depth-first traversal order with child nodes before parent nodes.
 264      */
 265     void (*bdrv_attach_aio_context)(BlockDriverState *bs,
 266                                     AioContext *new_context);
 267
 268     /* io queue for linux-aio */
 269     void (*bdrv_io_plug)(BlockDriverState *bs);
 270     void (*bdrv_io_unplug)(BlockDriverState *bs);
 271     void (*bdrv_flush_io_queue)(BlockDriverState *bs);
 272
 273     QLIST_ENTRY(BlockDriver) list;
 274 };
 275
 276 typedef struct BlockLimits {
 277     /* maximum number of sectors that can be discarded at once */
 278     int max_discard;
 279
 280     /* optimal alignment for discard requests in sectors */
 281     int64_t discard_alignment;
 282
 283     /* maximum number of sectors that can zeroized at once */
 284     int max_write_zeroes;
 285
 286     /* optimal alignment for write zeroes requests in sectors */
 287     int64_t write_zeroes_alignment;
 288
 289     /* optimal transfer length in sectors */
 290     int opt_transfer_length;
 291
 292     /* memory alignment so that no bounce buffer is needed */
 293     size_t opt_mem_alignment;
 294 } BlockLimits;
 295
 296 typedef struct BdrvOpBlocker BdrvOpBlocker;
 297
 298 typedef struct BdrvAioNotifier {
 299     void (*attached_aio_context)(AioContext *new_context, void *opaque);
 300     void (*detach_aio_context)(void *opaque);
 301
 302     void *opaque;
 303
 304     QLIST_ENTRY(BdrvAioNotifier) list;
 305 } BdrvAioNotifier;
 306
 307 /*
 308  * Note: the function bdrv_append() copies and swaps contents of
 309  * BlockDriverStates, so if you add new fields to this struct, please
 310  * inspect bdrv_append() to determine if the new fields need to be
 311  * copied as well.
 312  */
 313 struct BlockDriverState {
 314     int64_t total_sectors; /* if we are reading a disk image, give its
 315                               size in sectors */
 316     int read_only; /* if true, the media is read only */
 317     int open_flags; /* flags used to open the file, re-used for re-open */
 318     int encrypted; /* if true, the media is encrypted */
 319     int valid_key; /* if true, a valid encryption key has been set */
 320     int sg;        /* if true, the device is a /dev/sg* */
 321     int copy_on_read; /* if true, copy read backing sectors into image
 322                          note this is a reference count */
 323
 324     BlockDriver *drv; /* NULL means no media */
 325     void *opaque;
 326
 327     BlockBackend *blk;          /* owning backend, if any */
 328
 329     void *dev;                  /* attached device model, if any */
 330     /* TODO change to DeviceState when all users are qdevified */
 331     const BlockDevOps *dev_ops;
 332     void *dev_opaque;
 333
 334     AioContext *aio_context; /* event loop used for fd handlers, timers, etc */
 335     /* long-running tasks intended to always use the same AioContext as this
 336      * BDS may register themselves in this list to be notified of changes
 337      * regarding this BDS's context */
 338     QLIST_HEAD(, BdrvAioNotifier) aio_notifiers;
 339
 340     char filename[1024];
 341     char backing_file[1024]; /* if non zero, the image is a diff of
 342                                 this file image */
 343     char backing_format[16]; /* if non-zero and backing_file exists */
 344
 345     QDict *full_open_options;
 346     char exact_filename[1024];
 347
 348     BlockDriverState *backing_hd;
 349     BlockDriverState *file;
 350
 351     NotifierList close_notifiers;
 352
 353     /* Callback before write request is processed */
 354     NotifierWithReturnList before_write_notifiers;
 355
 356     /* number of in-flight serialising requests */
 357     unsigned int serialising_in_flight;
 358
 359     /* I/O throttling */
 360     ThrottleState throttle_state;
 361     CoQueue      throttled_reqs[2];
 362     bool         io_limits_enabled;
 363
 364     /* I/O stats (display with "info blockstats"). */
 365     BlockAcctStats stats;
 366
 367     /* I/O Limits */
 368     BlockLimits bl;
 369
 370     /* Whether the disk can expand beyond total_sectors */
 371     int growable;
 372
 373     /* Whether produces zeros when read beyond eof */
 374     bool zero_beyond_eof;
 375
 376     /* Alignment requirement for offset/length of I/O requests */
 377     unsigned int request_alignment;
 378
 379     /* the block size for which the guest device expects atomicity */
 380     int guest_block_size;
 381
 382     /* do we need to tell the quest if we have a volatile write cache? */
 383     int enable_write_cache;
 384
 385     /* NOTE: the following infos are only hints for real hardware
 386        drivers. They are not used by the block driver */
 387     BlockdevOnError on_read_error, on_write_error;
 388     bool iostatus_enabled;
 389     BlockDeviceIoStatus iostatus;
 390
 391     /* the following member gives a name to every node on the bs graph. */
 392     char node_name[32];
 393     /* element of the list of named nodes building the graph */
 394     QTAILQ_ENTRY(BlockDriverState) node_list;
 395     /* Device name is the name associated with the "drive" the guest sees */
 396     char device_name[32];
 397     /* element of the list of "drives" the guest sees */
 398     QTAILQ_ENTRY(BlockDriverState) device_list;
 399     QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps;
 400     int refcnt;
 401
 402     QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;
 403
 404     /* operation blockers */
 405     QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX];
 406
 407     /* long-running background operation */
 408     BlockJob *job;
 409
 410     QDict *options;
 411     BlockdevDetectZeroesOptions detect_zeroes;
 412
 413     /* The error object in use for blocking operations on backing_hd */
 414     Error *backing_blocker;
 415 };
 416
 417 int get_tmp_filename(char *filename, int size);
 418
 419 void bdrv_set_io_limits(BlockDriverState *bs,
 420                         ThrottleConfig *cfg);
 421
 422
 423 /**
 424  * bdrv_add_before_write_notifier:
 425  *
 426  * Register a callback that is invoked before write requests are processed but
 427  * after any throttling or waiting for overlapping requests.
 428  */
 429 void bdrv_add_before_write_notifier(BlockDriverState *bs,
 430                                     NotifierWithReturn *notifier);
 431
 432 /**
 433  * bdrv_detach_aio_context:
 434  *
 435  * May be called from .bdrv_detach_aio_context() to detach children from the
 436  * current #AioContext.  This is only needed by block drivers that manage their
 437  * own children.  Both ->file and ->backing_hd are automatically handled and
 438  * block drivers should not call this function on them explicitly.
 439  */
 440 void bdrv_detach_aio_context(BlockDriverState *bs);
 441
 442 /**
 443  * bdrv_attach_aio_context:
 444  *
 445  * May be called from .bdrv_attach_aio_context() to attach children to the new
 446  * #AioContext.  This is only needed by block drivers that manage their own
 447  * children.  Both ->file and ->backing_hd are automatically handled and block
 448  * drivers should not call this function on them explicitly.
 449  */
 450 void bdrv_attach_aio_context(BlockDriverState *bs,
 451                              AioContext *new_context);
 452
 453 /**
 454  * bdrv_add_aio_context_notifier:
 455  *
 456  * If a long-running job intends to be always run in the same AioContext as a
 457  * certain BDS, it may use this function to be notified of changes regarding the
 458  * association of the BDS to an AioContext.
 459  *
 460  * attached_aio_context() is called after the target BDS has been attached to a
 461  * new AioContext; detach_aio_context() is called before the target BDS is being
 462  * detached from its old AioContext.
 463  */
 464 void bdrv_add_aio_context_notifier(BlockDriverState *bs,
 465         void (*attached_aio_context)(AioContext *new_context, void *opaque),
 466         void (*detach_aio_context)(void *opaque), void *opaque);
 467
 468 /**
 469  * bdrv_remove_aio_context_notifier:
 470  *
 471  * Unsubscribe of change notifications regarding the BDS's AioContext. The
 472  * parameters given here have to be the same as those given to
 473  * bdrv_add_aio_context_notifier().
 474  */
 475 void bdrv_remove_aio_context_notifier(BlockDriverState *bs,
 476                                       void (*aio_context_attached)(AioContext *,
 477                                                                    void *),
 478                                       void (*aio_context_detached)(void *),
 479                                       void *opaque);
 480
 481 #ifdef _WIN32
 482 int is_windows_drive(const char *filename);
 483 #endif
 484
 485 /**
 486  * stream_start:
 487  * @bs: Block device to operate on.
 488  * @base: Block device that will become the new base, or %NULL to
 489  * flatten the whole backing file chain onto @bs.
 490  * @base_id: The file name that will be written to @bs as the new
 491  * backing file if the job completes.  Ignored if @base is %NULL.
 492  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 493  * @on_error: The action to take upon error.
 494  * @cb: Completion function for the job.
 495  * @opaque: Opaque pointer value passed to @cb.
 496  * @errp: Error object.
 497  *
 498  * Start a streaming operation on @bs.  Clusters that are unallocated
 499  * in @bs, but allocated in any image between @base and @bs (both
 500  * exclusive) will be written to @bs.  At the end of a successful
 501  * streaming job, the backing file of @bs will be changed to
 502  * @base_id in the written image and to @base in the live BlockDriverState.
 503  */
 504 void stream_start(BlockDriverState *bs, BlockDriverState *base,
 505                   const char *base_id, int64_t speed, BlockdevOnError on_error,
 506                   BlockDriverCompletionFunc *cb,
 507                   void *opaque, Error **errp);
 508
 509 /**
 510  * commit_start:
 511  * @bs: Active block device.
 512  * @top: Top block device to be committed.
 513  * @base: Block device that will be written into, and become the new top.
 514  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 515  * @on_error: The action to take upon error.
 516  * @cb: Completion function for the job.
 517  * @opaque: Opaque pointer value passed to @cb.
 518  * @backing_file_str: String to use as the backing file in @top's overlay
 519  * @errp: Error object.
 520  *
 521  */
 522 void commit_start(BlockDriverState *bs, BlockDriverState *base,
 523                  BlockDriverState *top, int64_t speed,
 524                  BlockdevOnError on_error, BlockDriverCompletionFunc *cb,
 525                  void *opaque, const char *backing_file_str, Error **errp);
 526 /**
 527  * commit_active_start:
 528  * @bs: Active block device to be committed.
 529  * @base: Block device that will be written into, and become the new top.
 530  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 531  * @on_error: The action to take upon error.
 532  * @cb: Completion function for the job.
 533  * @opaque: Opaque pointer value passed to @cb.
 534  * @errp: Error object.
 535  *
 536  */
 537 void commit_active_start(BlockDriverState *bs, BlockDriverState *base,
 538                          int64_t speed,
 539                          BlockdevOnError on_error,
 540                          BlockDriverCompletionFunc *cb,
 541                          void *opaque, Error **errp);
 542 /*
 543  * mirror_start:
 544  * @bs: Block device to operate on.
 545  * @target: Block device to write to.
 546  * @replaces: Block graph node name to replace once the mirror is done. Can
 547  *            only be used when full mirroring is selected.
 548  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 549  * @granularity: The chosen granularity for the dirty bitmap.
 550  * @buf_size: The amount of data that can be in flight at one time.
 551  * @mode: Whether to collapse all images in the chain to the target.
 552  * @on_source_error: The action to take upon error reading from the source.
 553  * @on_target_error: The action to take upon error writing to the target.
 554  * @cb: Completion function for the job.
 555  * @opaque: Opaque pointer value passed to @cb.
 556  * @errp: Error object.
 557  *
 558  * Start a mirroring operation on @bs.  Clusters that are allocated
 559  * in @bs will be written to @bs until the job is cancelled or
 560  * manually completed.  At the end of a successful mirroring job,
 561  * @bs will be switched to read from @target.
 562  */
 563 void mirror_start(BlockDriverState *bs, BlockDriverState *target,
 564                   const char *replaces,
 565                   int64_t speed, int64_t granularity, int64_t buf_size,
 566                   MirrorSyncMode mode, BlockdevOnError on_source_error,
 567                   BlockdevOnError on_target_error,
 568                   BlockDriverCompletionFunc *cb,
 569                   void *opaque, Error **errp);
 570
 571 /*
 572  * backup_start:
 573  * @bs: Block device to operate on.
 574  * @target: Block device to write to.
 575  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 576  * @sync_mode: What parts of the disk image should be copied to the destination.
 577  * @on_source_error: The action to take upon error reading from the source.
 578  * @on_target_error: The action to take upon error writing to the target.
 579  * @cb: Completion function for the job.
 580  * @opaque: Opaque pointer value passed to @cb.
 581  *
 582  * Start a backup operation on @bs.  Clusters in @bs are written to @target
 583  * until the job is cancelled or manually completed.
 584  */
 585 void backup_start(BlockDriverState *bs, BlockDriverState *target,
 586                   int64_t speed, MirrorSyncMode sync_mode,
 587                   BlockdevOnError on_source_error,
 588                   BlockdevOnError on_target_error,
 589                   BlockDriverCompletionFunc *cb, void *opaque,
 590                   Error **errp);
 591
 592 #endif /* BLOCK_INT_H */