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/block.h"
  28 #include "qemu/option.h"
  29 #include "qemu/queue.h"
  30 #include "block/coroutine.h"
  31 #include "qemu/timer.h"
  32 #include "qapi-types.h"
  33 #include "qapi/qmp/qerror.h"
  34 #include "monitor/monitor.h"
  35 #include "qemu/hbitmap.h"
  36 #include "block/snapshot.h"
  37 #include "qemu/main-loop.h"
  38 #include "qemu/throttle.h"
  39
  40 #define BLOCK_FLAG_ENCRYPT          1
  41 #define BLOCK_FLAG_COMPAT6          4
  42 #define BLOCK_FLAG_LAZY_REFCOUNTS   8
  43
  44 #define BLOCK_OPT_SIZE              "size"
  45 #define BLOCK_OPT_ENCRYPT           "encryption"
  46 #define BLOCK_OPT_COMPAT6           "compat6"
  47 #define BLOCK_OPT_BACKING_FILE      "backing_file"
  48 #define BLOCK_OPT_BACKING_FMT       "backing_fmt"
  49 #define BLOCK_OPT_CLUSTER_SIZE      "cluster_size"
  50 #define BLOCK_OPT_TABLE_SIZE        "table_size"
  51 #define BLOCK_OPT_PREALLOC          "preallocation"
  52 #define BLOCK_OPT_SUBFMT            "subformat"
  53 #define BLOCK_OPT_COMPAT_LEVEL      "compat"
  54 #define BLOCK_OPT_LAZY_REFCOUNTS    "lazy_refcounts"
  55 #define BLOCK_OPT_ADAPTER_TYPE      "adapter_type"
  56 #define BLOCK_OPT_REDUNDANCY        "redundancy"
  57
  58 typedef struct BdrvTrackedRequest {
  59     BlockDriverState *bs;
  60     int64_t offset;
  61     unsigned int bytes;
  62     bool is_write;
  63
  64     bool serialising;
  65     int64_t overlap_offset;
  66     unsigned int overlap_bytes;
  67
  68     QLIST_ENTRY(BdrvTrackedRequest) list;
  69     Coroutine *co; /* owner, used for deadlock detection */
  70     CoQueue wait_queue; /* coroutines blocked on this request */
  71
  72     struct BdrvTrackedRequest *waiting_for;
  73 } BdrvTrackedRequest;
  74
  75 struct BlockDriver {
  76     const char *format_name;
  77     int instance_size;
  78
  79     /* set to true if the BlockDriver is a block filter */
  80     bool is_filter;
  81     /* for snapshots block filter like Quorum can implement the
  82      * following recursive callback.
  83      * It's purpose is to recurse on the filter children while calling
  84      * bdrv_recurse_is_first_non_filter on them.
  85      * For a sample implementation look in the future Quorum block filter.
  86      */
  87     bool (*bdrv_recurse_is_first_non_filter)(BlockDriverState *bs,
  88                                              BlockDriverState *candidate);
  89
  90     int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename);
  91     int (*bdrv_probe_device)(const char *filename);
  92
  93     /* Any driver implementing this callback is expected to be able to handle
  94      * NULL file names in its .bdrv_open() implementation */
  95     void (*bdrv_parse_filename)(const char *filename, QDict *options, Error **errp);
  96     /* Drivers not implementing bdrv_parse_filename nor bdrv_open should have
  97      * this field set to true, except ones that are defined only by their
  98      * child's bs.
  99      * An example of the last type will be the quorum block driver.
 100      */
 101     bool bdrv_needs_filename;
 102
 103     /* For handling image reopen for split or non-split files */
 104     int (*bdrv_reopen_prepare)(BDRVReopenState *reopen_state,
 105                                BlockReopenQueue *queue, Error **errp);
 106     void (*bdrv_reopen_commit)(BDRVReopenState *reopen_state);
 107     void (*bdrv_reopen_abort)(BDRVReopenState *reopen_state);
 108
 109     int (*bdrv_open)(BlockDriverState *bs, QDict *options, int flags,
 110                      Error **errp);
 111     int (*bdrv_file_open)(BlockDriverState *bs, QDict *options, int flags,
 112                           Error **errp);
 113     int (*bdrv_read)(BlockDriverState *bs, int64_t sector_num,
 114                      uint8_t *buf, int nb_sectors);
 115     int (*bdrv_write)(BlockDriverState *bs, int64_t sector_num,
 116                       const uint8_t *buf, int nb_sectors);
 117     void (*bdrv_close)(BlockDriverState *bs);
 118     void (*bdrv_rebind)(BlockDriverState *bs);
 119     int (*bdrv_create)(const char *filename, QEMUOptionParameter *options,
 120                        Error **errp);
 121     int (*bdrv_set_key)(BlockDriverState *bs, const char *key);
 122     int (*bdrv_make_empty)(BlockDriverState *bs);
 123     /* aio */
 124     BlockDriverAIOCB *(*bdrv_aio_readv)(BlockDriverState *bs,
 125         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 126         BlockDriverCompletionFunc *cb, void *opaque);
 127     BlockDriverAIOCB *(*bdrv_aio_writev)(BlockDriverState *bs,
 128         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 129         BlockDriverCompletionFunc *cb, void *opaque);
 130     BlockDriverAIOCB *(*bdrv_aio_flush)(BlockDriverState *bs,
 131         BlockDriverCompletionFunc *cb, void *opaque);
 132     BlockDriverAIOCB *(*bdrv_aio_discard)(BlockDriverState *bs,
 133         int64_t sector_num, int nb_sectors,
 134         BlockDriverCompletionFunc *cb, void *opaque);
 135
 136     int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs,
 137         int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
 138     int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs,
 139         int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
 140     /*
 141      * Efficiently zero a region of the disk image.  Typically an image format
 142      * would use a compact metadata representation to implement this.  This
 143      * function pointer may be NULL and .bdrv_co_writev() will be called
 144      * instead.
 145      */
 146     int coroutine_fn (*bdrv_co_write_zeroes)(BlockDriverState *bs,
 147         int64_t sector_num, int nb_sectors, BdrvRequestFlags flags);
 148     int coroutine_fn (*bdrv_co_discard)(BlockDriverState *bs,
 149         int64_t sector_num, int nb_sectors);
 150     int64_t coroutine_fn (*bdrv_co_get_block_status)(BlockDriverState *bs,
 151         int64_t sector_num, int nb_sectors, int *pnum);
 152
 153     /*
 154      * Invalidate any cached meta-data.
 155      */
 156     void (*bdrv_invalidate_cache)(BlockDriverState *bs, Error **errp);
 157
 158     /*
 159      * Flushes all data that was already written to the OS all the way down to
 160      * the disk (for example raw-posix calls fsync()).
 161      */
 162     int coroutine_fn (*bdrv_co_flush_to_disk)(BlockDriverState *bs);
 163
 164     /*
 165      * Flushes all internal caches to the OS. The data may still sit in a
 166      * writeback cache of the host OS, but it will survive a crash of the qemu
 167      * process.
 168      */
 169     int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs);
 170
 171     const char *protocol_name;
 172     int (*bdrv_truncate)(BlockDriverState *bs, int64_t offset);
 173
 174     int64_t (*bdrv_getlength)(BlockDriverState *bs);
 175     bool has_variable_length;
 176     int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs);
 177
 178     int (*bdrv_write_compressed)(BlockDriverState *bs, int64_t sector_num,
 179                                  const uint8_t *buf, int nb_sectors);
 180
 181     int (*bdrv_snapshot_create)(BlockDriverState *bs,
 182                                 QEMUSnapshotInfo *sn_info);
 183     int (*bdrv_snapshot_goto)(BlockDriverState *bs,
 184                               const char *snapshot_id);
 185     int (*bdrv_snapshot_delete)(BlockDriverState *bs,
 186                                 const char *snapshot_id,
 187                                 const char *name,
 188                                 Error **errp);
 189     int (*bdrv_snapshot_list)(BlockDriverState *bs,
 190                               QEMUSnapshotInfo **psn_info);
 191     int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs,
 192                                   const char *snapshot_id,
 193                                   const char *name,
 194                                   Error **errp);
 195     int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi);
 196     ImageInfoSpecific *(*bdrv_get_specific_info)(BlockDriverState *bs);
 197
 198     int (*bdrv_save_vmstate)(BlockDriverState *bs, QEMUIOVector *qiov,
 199                              int64_t pos);
 200     int (*bdrv_load_vmstate)(BlockDriverState *bs, uint8_t *buf,
 201                              int64_t pos, int size);
 202
 203     int (*bdrv_change_backing_file)(BlockDriverState *bs,
 204         const char *backing_file, const char *backing_fmt);
 205
 206     /* removable device specific */
 207     int (*bdrv_is_inserted)(BlockDriverState *bs);
 208     int (*bdrv_media_changed)(BlockDriverState *bs);
 209     void (*bdrv_eject)(BlockDriverState *bs, bool eject_flag);
 210     void (*bdrv_lock_medium)(BlockDriverState *bs, bool locked);
 211
 212     /* to control generic scsi devices */
 213     int (*bdrv_ioctl)(BlockDriverState *bs, unsigned long int req, void *buf);
 214     BlockDriverAIOCB *(*bdrv_aio_ioctl)(BlockDriverState *bs,
 215         unsigned long int req, void *buf,
 216         BlockDriverCompletionFunc *cb, void *opaque);
 217
 218     /* List of options for creating images, terminated by name == NULL */
 219     QEMUOptionParameter *create_options;
 220
 221
 222     /*
 223      * Returns 0 for completed check, -errno for internal errors.
 224      * The check results are stored in result.
 225      */
 226     int (*bdrv_check)(BlockDriverState* bs, BdrvCheckResult *result,
 227         BdrvCheckMode fix);
 228
 229     int (*bdrv_amend_options)(BlockDriverState *bs,
 230         QEMUOptionParameter *options);
 231
 232     void (*bdrv_debug_event)(BlockDriverState *bs, BlkDebugEvent event);
 233
 234     /* TODO Better pass a option string/QDict/QemuOpts to add any rule? */
 235     int (*bdrv_debug_breakpoint)(BlockDriverState *bs, const char *event,
 236         const char *tag);
 237     int (*bdrv_debug_remove_breakpoint)(BlockDriverState *bs,
 238         const char *tag);
 239     int (*bdrv_debug_resume)(BlockDriverState *bs, const char *tag);
 240     bool (*bdrv_debug_is_suspended)(BlockDriverState *bs, const char *tag);
 241
 242     int (*bdrv_refresh_limits)(BlockDriverState *bs);
 243
 244     /*
 245      * Returns 1 if newly created images are guaranteed to contain only
 246      * zeros, 0 otherwise.
 247      */
 248     int (*bdrv_has_zero_init)(BlockDriverState *bs);
 249
 250     QLIST_ENTRY(BlockDriver) list;
 251 };
 252
 253 typedef struct BlockLimits {
 254     /* maximum number of sectors that can be discarded at once */
 255     int max_discard;
 256
 257     /* optimal alignment for discard requests in sectors */
 258     int64_t discard_alignment;
 259
 260     /* maximum number of sectors that can zeroized at once */
 261     int max_write_zeroes;
 262
 263     /* optimal alignment for write zeroes requests in sectors */
 264     int64_t write_zeroes_alignment;
 265
 266     /* optimal transfer length in sectors */
 267     int opt_transfer_length;
 268
 269     /* memory alignment so that no bounce buffer is needed */
 270     size_t opt_mem_alignment;
 271 } BlockLimits;
 272
 273 typedef struct BdrvOpBlocker BdrvOpBlocker;
 274
 275 /*
 276  * Note: the function bdrv_append() copies and swaps contents of
 277  * BlockDriverStates, so if you add new fields to this struct, please
 278  * inspect bdrv_append() to determine if the new fields need to be
 279  * copied as well.
 280  */
 281 struct BlockDriverState {
 282     int64_t total_sectors; /* if we are reading a disk image, give its
 283                               size in sectors */
 284     int read_only; /* if true, the media is read only */
 285     int open_flags; /* flags used to open the file, re-used for re-open */
 286     int encrypted; /* if true, the media is encrypted */
 287     int valid_key; /* if true, a valid encryption key has been set */
 288     int sg;        /* if true, the device is a /dev/sg* */
 289     int copy_on_read; /* if true, copy read backing sectors into image
 290                          note this is a reference count */
 291
 292     BlockDriver *drv; /* NULL means no media */
 293     void *opaque;
 294
 295     void *dev;                  /* attached device model, if any */
 296     /* TODO change to DeviceState when all users are qdevified */
 297     const BlockDevOps *dev_ops;
 298     void *dev_opaque;
 299
 300     char filename[1024];
 301     char backing_file[1024]; /* if non zero, the image is a diff of
 302                                 this file image */
 303     char backing_format[16]; /* if non-zero and backing_file exists */
 304
 305     BlockDriverState *backing_hd;
 306     BlockDriverState *file;
 307
 308     NotifierList close_notifiers;
 309
 310     /* Callback before write request is processed */
 311     NotifierWithReturnList before_write_notifiers;
 312
 313     /* number of in-flight serialising requests */
 314     unsigned int serialising_in_flight;
 315
 316     /* I/O throttling */
 317     ThrottleState throttle_state;
 318     CoQueue      throttled_reqs[2];
 319     bool         io_limits_enabled;
 320
 321     /* I/O stats (display with "info blockstats"). */
 322     uint64_t nr_bytes[BDRV_MAX_IOTYPE];
 323     uint64_t nr_ops[BDRV_MAX_IOTYPE];
 324     uint64_t total_time_ns[BDRV_MAX_IOTYPE];
 325     uint64_t wr_highest_sector;
 326
 327     /* I/O Limits */
 328     BlockLimits bl;
 329
 330     /* Whether the disk can expand beyond total_sectors */
 331     int growable;
 332
 333     /* Whether produces zeros when read beyond eof */
 334     bool zero_beyond_eof;
 335
 336     /* Alignment requirement for offset/length of I/O requests */
 337     unsigned int request_alignment;
 338
 339     /* the block size for which the guest device expects atomicity */
 340     int guest_block_size;
 341
 342     /* do we need to tell the quest if we have a volatile write cache? */
 343     int enable_write_cache;
 344
 345     /* NOTE: the following infos are only hints for real hardware
 346        drivers. They are not used by the block driver */
 347     BlockdevOnError on_read_error, on_write_error;
 348     bool iostatus_enabled;
 349     BlockDeviceIoStatus iostatus;
 350
 351     /* the following member gives a name to every node on the bs graph. */
 352     char node_name[32];
 353     /* element of the list of named nodes building the graph */
 354     QTAILQ_ENTRY(BlockDriverState) node_list;
 355     /* Device name is the name associated with the "drive" the guest sees */
 356     char device_name[32];
 357     /* element of the list of "drives" the guest sees */
 358     QTAILQ_ENTRY(BlockDriverState) device_list;
 359     QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps;
 360     int refcnt;
 361
 362     QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;
 363
 364     /* operation blockers */
 365     QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX];
 366
 367     /* long-running background operation */
 368     BlockJob *job;
 369
 370     QDict *options;
 371     BlockdevDetectZeroesOptions detect_zeroes;
 372 };
 373
 374 int get_tmp_filename(char *filename, int size);
 375
 376 void bdrv_set_io_limits(BlockDriverState *bs,
 377                         ThrottleConfig *cfg);
 378
 379
 380 /**
 381  * bdrv_add_before_write_notifier:
 382  *
 383  * Register a callback that is invoked before write requests are processed but
 384  * after any throttling or waiting for overlapping requests.
 385  */
 386 void bdrv_add_before_write_notifier(BlockDriverState *bs,
 387                                     NotifierWithReturn *notifier);
 388
 389 /**
 390  * bdrv_get_aio_context:
 391  *
 392  * Returns: the currently bound #AioContext
 393  */
 394 AioContext *bdrv_get_aio_context(BlockDriverState *bs);
 395
 396 #ifdef _WIN32
 397 int is_windows_drive(const char *filename);
 398 #endif
 399 void bdrv_emit_qmp_error_event(const BlockDriverState *bdrv,
 400                                enum MonitorEvent ev,
 401                                BlockErrorAction action, bool is_read);
 402
 403 /**
 404  * stream_start:
 405  * @bs: Block device to operate on.
 406  * @base: Block device that will become the new base, or %NULL to
 407  * flatten the whole backing file chain onto @bs.
 408  * @base_id: The file name that will be written to @bs as the new
 409  * backing file if the job completes.  Ignored if @base is %NULL.
 410  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 411  * @on_error: The action to take upon error.
 412  * @cb: Completion function for the job.
 413  * @opaque: Opaque pointer value passed to @cb.
 414  * @errp: Error object.
 415  *
 416  * Start a streaming operation on @bs.  Clusters that are unallocated
 417  * in @bs, but allocated in any image between @base and @bs (both
 418  * exclusive) will be written to @bs.  At the end of a successful
 419  * streaming job, the backing file of @bs will be changed to
 420  * @base_id in the written image and to @base in the live BlockDriverState.
 421  */
 422 void stream_start(BlockDriverState *bs, BlockDriverState *base,
 423                   const char *base_id, int64_t speed, BlockdevOnError on_error,
 424                   BlockDriverCompletionFunc *cb,
 425                   void *opaque, Error **errp);
 426
 427 /**
 428  * commit_start:
 429  * @bs: Active block device.
 430  * @top: Top block device to be committed.
 431  * @base: Block device that will be written into, and become the new top.
 432  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 433  * @on_error: The action to take upon error.
 434  * @cb: Completion function for the job.
 435  * @opaque: Opaque pointer value passed to @cb.
 436  * @errp: Error object.
 437  *
 438  */
 439 void commit_start(BlockDriverState *bs, BlockDriverState *base,
 440                  BlockDriverState *top, int64_t speed,
 441                  BlockdevOnError on_error, BlockDriverCompletionFunc *cb,
 442                  void *opaque, Error **errp);
 443 /**
 444  * commit_active_start:
 445  * @bs: Active block device to be committed.
 446  * @base: Block device that will be written into, and become the new top.
 447  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 448  * @on_error: The action to take upon error.
 449  * @cb: Completion function for the job.
 450  * @opaque: Opaque pointer value passed to @cb.
 451  * @errp: Error object.
 452  *
 453  */
 454 void commit_active_start(BlockDriverState *bs, BlockDriverState *base,
 455                          int64_t speed,
 456                          BlockdevOnError on_error,
 457                          BlockDriverCompletionFunc *cb,
 458                          void *opaque, Error **errp);
 459 /*
 460  * mirror_start:
 461  * @bs: Block device to operate on.
 462  * @target: Block device to write to.
 463  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 464  * @granularity: The chosen granularity for the dirty bitmap.
 465  * @buf_size: The amount of data that can be in flight at one time.
 466  * @mode: Whether to collapse all images in the chain to the target.
 467  * @on_source_error: The action to take upon error reading from the source.
 468  * @on_target_error: The action to take upon error writing to the target.
 469  * @cb: Completion function for the job.
 470  * @opaque: Opaque pointer value passed to @cb.
 471  * @errp: Error object.
 472  *
 473  * Start a mirroring operation on @bs.  Clusters that are allocated
 474  * in @bs will be written to @bs until the job is cancelled or
 475  * manually completed.  At the end of a successful mirroring job,
 476  * @bs will be switched to read from @target.
 477  */
 478 void mirror_start(BlockDriverState *bs, BlockDriverState *target,
 479                   int64_t speed, int64_t granularity, int64_t buf_size,
 480                   MirrorSyncMode mode, BlockdevOnError on_source_error,
 481                   BlockdevOnError on_target_error,
 482                   BlockDriverCompletionFunc *cb,
 483                   void *opaque, Error **errp);
 484
 485 /*
 486  * backup_start:
 487  * @bs: Block device to operate on.
 488  * @target: Block device to write to.
 489  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 490  * @sync_mode: What parts of the disk image should be copied to the destination.
 491  * @on_source_error: The action to take upon error reading from the source.
 492  * @on_target_error: The action to take upon error writing to the target.
 493  * @cb: Completion function for the job.
 494  * @opaque: Opaque pointer value passed to @cb.
 495  *
 496  * Start a backup operation on @bs.  Clusters in @bs are written to @target
 497  * until the job is cancelled or manually completed.
 498  */
 499 void backup_start(BlockDriverState *bs, BlockDriverState *target,
 500                   int64_t speed, MirrorSyncMode sync_mode,
 501                   BlockdevOnError on_source_error,
 502                   BlockdevOnError on_target_error,
 503                   BlockDriverCompletionFunc *cb, void *opaque,
 504                   Error **errp);
 505
 506 #endif /* BLOCK_INT_H */