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.h"
  28 #include "qemu-option.h"
  29 #include "qemu-queue.h"
  30 #include "qemu-coroutine.h"
  31 #include "qemu-timer.h"
  32 #include "qapi-types.h"
  33
  34 #define BLOCK_FLAG_ENCRYPT      1
  35 #define BLOCK_FLAG_COMPAT6      4
  36
  37 #define BLOCK_IO_LIMIT_READ     0
  38 #define BLOCK_IO_LIMIT_WRITE    1
  39 #define BLOCK_IO_LIMIT_TOTAL    2
  40
  41 #define BLOCK_IO_SLICE_TIME     100000000
  42 #define NANOSECONDS_PER_SECOND  1000000000.0
  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
  55 typedef struct BdrvTrackedRequest BdrvTrackedRequest;
  56
  57 typedef struct BlockIOLimit {
  58     int64_t bps[3];
  59     int64_t iops[3];
  60 } BlockIOLimit;
  61
  62 typedef struct BlockIOBaseValue {
  63     uint64_t bytes[2];
  64     uint64_t ios[2];
  65 } BlockIOBaseValue;
  66
  67 typedef struct BlockJob BlockJob;
  68
  69 /**
  70  * BlockJobType:
  71  *
  72  * A class type for block job objects.
  73  */
  74 typedef struct BlockJobType {
  75     /** Derived BlockJob struct size */
  76     size_t instance_size;
  77
  78     /** String describing the operation, part of query-block-jobs QMP API */
  79     const char *job_type;
  80
  81     /** Optional callback for job types that support setting a speed limit */
  82     void (*set_speed)(BlockJob *job, int64_t speed, Error **errp);
  83 } BlockJobType;
  84
  85 /**
  86  * BlockJob:
  87  *
  88  * Long-running operation on a BlockDriverState.
  89  */
  90 struct BlockJob {
  91     /** The job type, including the job vtable.  */
  92     const BlockJobType *job_type;
  93
  94     /** The block device on which the job is operating.  */
  95     BlockDriverState *bs;
  96
  97     /**
  98      * The coroutine that executes the job.  If not NULL, it is
  99      * reentered when busy is false and the job is cancelled.
 100      */
 101     Coroutine *co;
 102
 103     /**
 104      * Set to true if the job should cancel itself.  The flag must
 105      * always be tested just before toggling the busy flag from false
 106      * to true.  After a job has been cancelled, it should only yield
 107      * if #qemu_aio_wait will ("sooner or later") reenter the coroutine.
 108      */
 109     bool cancelled;
 110
 111     /**
 112      * Set to false by the job while it is in a quiescent state, where
 113      * no I/O is pending and the job has yielded on any condition
 114      * that is not detected by #qemu_aio_wait, such as a timer.
 115      */
 116     bool busy;
 117
 118     /** Offset that is published by the query-block-jobs QMP API */
 119     int64_t offset;
 120
 121     /** Length that is published by the query-block-jobs QMP API */
 122     int64_t len;
 123
 124     /** Speed that was set with @block_job_set_speed.  */
 125     int64_t speed;
 126
 127     /** The completion function that will be called when the job completes.  */
 128     BlockDriverCompletionFunc *cb;
 129
 130     /** The opaque value that is passed to the completion function.  */
 131     void *opaque;
 132 };
 133
 134 struct BlockDriver {
 135     const char *format_name;
 136     int instance_size;
 137     int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename);
 138     int (*bdrv_probe_device)(const char *filename);
 139     int (*bdrv_open)(BlockDriverState *bs, int flags);
 140     int (*bdrv_file_open)(BlockDriverState *bs, const char *filename, int flags);
 141     int (*bdrv_read)(BlockDriverState *bs, int64_t sector_num,
 142                      uint8_t *buf, int nb_sectors);
 143     int (*bdrv_write)(BlockDriverState *bs, int64_t sector_num,
 144                       const uint8_t *buf, int nb_sectors);
 145     void (*bdrv_close)(BlockDriverState *bs);
 146     void (*bdrv_rebind)(BlockDriverState *bs);
 147     int (*bdrv_create)(const char *filename, QEMUOptionParameter *options);
 148     int (*bdrv_set_key)(BlockDriverState *bs, const char *key);
 149     int (*bdrv_make_empty)(BlockDriverState *bs);
 150     /* aio */
 151     BlockDriverAIOCB *(*bdrv_aio_readv)(BlockDriverState *bs,
 152         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 153         BlockDriverCompletionFunc *cb, void *opaque);
 154     BlockDriverAIOCB *(*bdrv_aio_writev)(BlockDriverState *bs,
 155         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 156         BlockDriverCompletionFunc *cb, void *opaque);
 157     BlockDriverAIOCB *(*bdrv_aio_flush)(BlockDriverState *bs,
 158         BlockDriverCompletionFunc *cb, void *opaque);
 159     BlockDriverAIOCB *(*bdrv_aio_discard)(BlockDriverState *bs,
 160         int64_t sector_num, int nb_sectors,
 161         BlockDriverCompletionFunc *cb, void *opaque);
 162
 163     int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs,
 164         int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
 165     int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs,
 166         int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
 167     /*
 168      * Efficiently zero a region of the disk image.  Typically an image format
 169      * would use a compact metadata representation to implement this.  This
 170      * function pointer may be NULL and .bdrv_co_writev() will be called
 171      * instead.
 172      */
 173     int coroutine_fn (*bdrv_co_write_zeroes)(BlockDriverState *bs,
 174         int64_t sector_num, int nb_sectors);
 175     int coroutine_fn (*bdrv_co_discard)(BlockDriverState *bs,
 176         int64_t sector_num, int nb_sectors);
 177     int coroutine_fn (*bdrv_co_is_allocated)(BlockDriverState *bs,
 178         int64_t sector_num, int nb_sectors, int *pnum);
 179
 180     /*
 181      * Invalidate any cached meta-data.
 182      */
 183     void (*bdrv_invalidate_cache)(BlockDriverState *bs);
 184
 185     /*
 186      * Flushes all data that was already written to the OS all the way down to
 187      * the disk (for example raw-posix calls fsync()).
 188      */
 189     int coroutine_fn (*bdrv_co_flush_to_disk)(BlockDriverState *bs);
 190
 191     /*
 192      * Flushes all internal caches to the OS. The data may still sit in a
 193      * writeback cache of the host OS, but it will survive a crash of the qemu
 194      * process.
 195      */
 196     int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs);
 197
 198     const char *protocol_name;
 199     int (*bdrv_truncate)(BlockDriverState *bs, int64_t offset);
 200     int64_t (*bdrv_getlength)(BlockDriverState *bs);
 201     int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs);
 202     int (*bdrv_write_compressed)(BlockDriverState *bs, int64_t sector_num,
 203                                  const uint8_t *buf, int nb_sectors);
 204
 205     int (*bdrv_snapshot_create)(BlockDriverState *bs,
 206                                 QEMUSnapshotInfo *sn_info);
 207     int (*bdrv_snapshot_goto)(BlockDriverState *bs,
 208                               const char *snapshot_id);
 209     int (*bdrv_snapshot_delete)(BlockDriverState *bs, const char *snapshot_id);
 210     int (*bdrv_snapshot_list)(BlockDriverState *bs,
 211                               QEMUSnapshotInfo **psn_info);
 212     int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs,
 213                                   const char *snapshot_name);
 214     int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi);
 215
 216     int (*bdrv_save_vmstate)(BlockDriverState *bs, const uint8_t *buf,
 217                              int64_t pos, int size);
 218     int (*bdrv_load_vmstate)(BlockDriverState *bs, uint8_t *buf,
 219                              int64_t pos, int size);
 220
 221     int (*bdrv_change_backing_file)(BlockDriverState *bs,
 222         const char *backing_file, const char *backing_fmt);
 223
 224     /* removable device specific */
 225     int (*bdrv_is_inserted)(BlockDriverState *bs);
 226     int (*bdrv_media_changed)(BlockDriverState *bs);
 227     void (*bdrv_eject)(BlockDriverState *bs, bool eject_flag);
 228     void (*bdrv_lock_medium)(BlockDriverState *bs, bool locked);
 229
 230     /* to control generic scsi devices */
 231     int (*bdrv_ioctl)(BlockDriverState *bs, unsigned long int req, void *buf);
 232     BlockDriverAIOCB *(*bdrv_aio_ioctl)(BlockDriverState *bs,
 233         unsigned long int req, void *buf,
 234         BlockDriverCompletionFunc *cb, void *opaque);
 235
 236     /* List of options for creating images, terminated by name == NULL */
 237     QEMUOptionParameter *create_options;
 238
 239
 240     /*
 241      * Returns 0 for completed check, -errno for internal errors.
 242      * The check results are stored in result.
 243      */
 244     int (*bdrv_check)(BlockDriverState* bs, BdrvCheckResult *result,
 245         BdrvCheckMode fix);
 246
 247     void (*bdrv_debug_event)(BlockDriverState *bs, BlkDebugEvent event);
 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     QLIST_ENTRY(BlockDriver) list;
 256 };
 257
 258 /*
 259  * Note: the function bdrv_append() copies and swaps contents of
 260  * BlockDriverStates, so if you add new fields to this struct, please
 261  * inspect bdrv_append() to determine if the new fields need to be
 262  * copied as well.
 263  */
 264 struct BlockDriverState {
 265     int64_t total_sectors; /* if we are reading a disk image, give its
 266                               size in sectors */
 267     int read_only; /* if true, the media is read only */
 268     int keep_read_only; /* if true, the media was requested to stay read only */
 269     int open_flags; /* flags used to open the file, re-used for re-open */
 270     int encrypted; /* if true, the media is encrypted */
 271     int valid_key; /* if true, a valid encryption key has been set */
 272     int sg;        /* if true, the device is a /dev/sg* */
 273     int copy_on_read; /* if true, copy read backing sectors into image
 274                          note this is a reference count */
 275
 276     BlockDriver *drv; /* NULL means no media */
 277     void *opaque;
 278
 279     void *dev;                  /* attached device model, if any */
 280     /* TODO change to DeviceState when all users are qdevified */
 281     const BlockDevOps *dev_ops;
 282     void *dev_opaque;
 283
 284     char filename[1024];
 285     char backing_file[1024]; /* if non zero, the image is a diff of
 286                                 this file image */
 287     char backing_format[16]; /* if non-zero and backing_file exists */
 288     int is_temporary;
 289
 290     BlockDriverState *backing_hd;
 291     BlockDriverState *file;
 292
 293     /* number of in-flight copy-on-read requests */
 294     unsigned int copy_on_read_in_flight;
 295
 296     /* the time for latest disk I/O */
 297     int64_t slice_time;
 298     int64_t slice_start;
 299     int64_t slice_end;
 300     BlockIOLimit io_limits;
 301     BlockIOBaseValue  io_base;
 302     CoQueue      throttled_reqs;
 303     QEMUTimer    *block_timer;
 304     bool         io_limits_enabled;
 305
 306     /* I/O stats (display with "info blockstats"). */
 307     uint64_t nr_bytes[BDRV_MAX_IOTYPE];
 308     uint64_t nr_ops[BDRV_MAX_IOTYPE];
 309     uint64_t total_time_ns[BDRV_MAX_IOTYPE];
 310     uint64_t wr_highest_sector;
 311
 312     /* Whether the disk can expand beyond total_sectors */
 313     int growable;
 314
 315     /* the memory alignment required for the buffers handled by this driver */
 316     int buffer_alignment;
 317
 318     /* do we need to tell the quest if we have a volatile write cache? */
 319     int enable_write_cache;
 320
 321     /* NOTE: the following infos are only hints for real hardware
 322        drivers. They are not used by the block driver */
 323     BlockErrorAction on_read_error, on_write_error;
 324     bool iostatus_enabled;
 325     BlockDeviceIoStatus iostatus;
 326     char device_name[32];
 327     unsigned long *dirty_bitmap;
 328     int64_t dirty_count;
 329     int in_use; /* users other than guest access, eg. block migration */
 330     QTAILQ_ENTRY(BlockDriverState) list;
 331
 332     QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;
 333
 334     /* long-running background operation */
 335     BlockJob *job;
 336 };
 337
 338 int get_tmp_filename(char *filename, int size);
 339
 340 void bdrv_set_io_limits(BlockDriverState *bs,
 341                         BlockIOLimit *io_limits);
 342
 343 #ifdef _WIN32
 344 int is_windows_drive(const char *filename);
 345 #endif
 346
 347 /**
 348  * block_job_create:
 349  * @job_type: The class object for the newly-created job.
 350  * @bs: The block
 351  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 352  * @cb: Completion function for the job.
 353  * @opaque: Opaque pointer value passed to @cb.
 354  * @errp: Error object.
 355  *
 356  * Create a new long-running block device job and return it.  The job
 357  * will call @cb asynchronously when the job completes.  Note that
 358  * @bs may have been closed at the time the @cb it is called.  If
 359  * this is the case, the job may be reported as either cancelled or
 360  * completed.
 361  *
 362  * This function is not part of the public job interface; it should be
 363  * called from a wrapper that is specific to the job type.
 364  */
 365 void *block_job_create(const BlockJobType *job_type, BlockDriverState *bs,
 366                        int64_t speed, BlockDriverCompletionFunc *cb,
 367                        void *opaque, Error **errp);
 368
 369 /**
 370  * block_job_sleep_ns:
 371  * @job: The job that calls the function.
 372  * @clock: The clock to sleep on.
 373  * @ns: How many nanoseconds to stop for.
 374  *
 375  * Put the job to sleep (assuming that it wasn't canceled) for @ns
 376  * nanoseconds.  Canceling the job will interrupt the wait immediately.
 377  */
 378 void block_job_sleep_ns(BlockJob *job, QEMUClock *clock, int64_t ns);
 379
 380 /**
 381  * block_job_complete:
 382  * @job: The job being completed.
 383  * @ret: The status code.
 384  *
 385  * Call the completion function that was registered at creation time, and
 386  * free @job.
 387  */
 388 void block_job_complete(BlockJob *job, int ret);
 389
 390 /**
 391  * block_job_set_speed:
 392  * @job: The job to set the speed for.
 393  * @speed: The new value
 394  * @errp: Error object.
 395  *
 396  * Set a rate-limiting parameter for the job; the actual meaning may
 397  * vary depending on the job type.
 398  */
 399 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp);
 400
 401 /**
 402  * block_job_cancel:
 403  * @job: The job to be canceled.
 404  *
 405  * Asynchronously cancel the specified job.
 406  */
 407 void block_job_cancel(BlockJob *job);
 408
 409 /**
 410  * block_job_is_cancelled:
 411  * @job: The job being queried.
 412  *
 413  * Returns whether the job is scheduled for cancellation.
 414  */
 415 bool block_job_is_cancelled(BlockJob *job);
 416
 417 /**
 418  * block_job_cancel:
 419  * @job: The job to be canceled.
 420  *
 421  * Asynchronously cancel the job and wait for it to reach a quiescent
 422  * state.  Note that the completion callback will still be called
 423  * asynchronously, hence it is *not* valid to call #bdrv_delete
 424  * immediately after #block_job_cancel_sync.  Users of block jobs
 425  * will usually protect the BlockDriverState objects with a reference
 426  * count, should this be a concern.
 427  *
 428  * Returns the return value from the job if the job actually completed
 429  * during the call, or -ECANCELED if it was canceled.
 430  */
 431 int block_job_cancel_sync(BlockJob *job);
 432
 433 /**
 434  * stream_start:
 435  * @bs: Block device to operate on.
 436  * @base: Block device that will become the new base, or %NULL to
 437  * flatten the whole backing file chain onto @bs.
 438  * @base_id: The file name that will be written to @bs as the new
 439  * backing file if the job completes.  Ignored if @base is %NULL.
 440  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
 441  * @cb: Completion function for the job.
 442  * @opaque: Opaque pointer value passed to @cb.
 443  * @errp: Error object.
 444  *
 445  * Start a streaming operation on @bs.  Clusters that are unallocated
 446  * in @bs, but allocated in any image between @base and @bs (both
 447  * exclusive) will be written to @bs.  At the end of a successful
 448  * streaming job, the backing file of @bs will be changed to
 449  * @base_id in the written image and to @base in the live BlockDriverState.
 450  */
 451 void stream_start(BlockDriverState *bs, BlockDriverState *base,
 452                   const char *base_id, int64_t speed,
 453                   BlockDriverCompletionFunc *cb,
 454                   void *opaque, Error **errp);
 455
 456 #endif /* BLOCK_INT_H */