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
  54 typedef struct BdrvTrackedRequest BdrvTrackedRequest;
  55
  56 typedef struct BlockIOLimit {
  57     int64_t bps[3];
  58     int64_t iops[3];
  59 } BlockIOLimit;
  60
  61 typedef struct BlockIOBaseValue {
  62     uint64_t bytes[2];
  63     uint64_t ios[2];
  64 } BlockIOBaseValue;
  65
  66 typedef struct BlockJob BlockJob;
  67
  68 /**
  69  * BlockJobType:
  70  *
  71  * A class type for block job objects.
  72  */
  73 typedef struct BlockJobType {
  74     /** Derived BlockJob struct size */
  75     size_t instance_size;
  76
  77     /** String describing the operation, part of query-block-jobs QMP API */
  78     const char *job_type;
  79
  80     /** Optional callback for job types that support setting a speed limit */
  81     int (*set_speed)(BlockJob *job, int64_t value);
  82 } BlockJobType;
  83
  84 /**
  85  * BlockJob:
  86  *
  87  * Long-running operation on a BlockDriverState.
  88  */
  89 struct BlockJob {
  90     /** The job type, including the job vtable.  */
  91     const BlockJobType *job_type;
  92
  93     /** The block device on which the job is operating.  */
  94     BlockDriverState *bs;
  95
  96     /**
  97      * Set to true if the job should cancel itself.  The flag must
  98      * always be tested just before toggling the busy flag from false
  99      * to true.  After a job has detected that the cancelled flag is
 100      * true, it should not anymore issue any I/O operation to the
 101      * block device.
 102      */
 103     bool cancelled;
 104
 105     /**
 106      * Set to false by the job while it is in a quiescent state, where
 107      * no I/O is pending and cancellation can be processed without
 108      * issuing new I/O.  The busy flag must be set to false when the
 109      * job goes to sleep on any condition that is not detected by
 110      * #qemu_aio_wait, such as a timer.
 111      */
 112     bool busy;
 113
 114     /** Offset that is published by the query-block-jobs QMP API */
 115     int64_t offset;
 116
 117     /** Length that is published by the query-block-jobs QMP API */
 118     int64_t len;
 119
 120     /** Speed that was set with @block_job_set_speed.  */
 121     int64_t speed;
 122
 123     /** The completion function that will be called when the job completes.  */
 124     BlockDriverCompletionFunc *cb;
 125
 126     /** The opaque value that is passed to the completion function.  */
 127     void *opaque;
 128 };
 129
 130 struct BlockDriver {
 131     const char *format_name;
 132     int instance_size;
 133     int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename);
 134     int (*bdrv_probe_device)(const char *filename);
 135     int (*bdrv_open)(BlockDriverState *bs, int flags);
 136     int (*bdrv_file_open)(BlockDriverState *bs, const char *filename, int flags);
 137     int (*bdrv_read)(BlockDriverState *bs, int64_t sector_num,
 138                      uint8_t *buf, int nb_sectors);
 139     int (*bdrv_write)(BlockDriverState *bs, int64_t sector_num,
 140                       const uint8_t *buf, int nb_sectors);
 141     void (*bdrv_close)(BlockDriverState *bs);
 142     int (*bdrv_create)(const char *filename, QEMUOptionParameter *options);
 143     int (*bdrv_set_key)(BlockDriverState *bs, const char *key);
 144     int (*bdrv_make_empty)(BlockDriverState *bs);
 145     /* aio */
 146     BlockDriverAIOCB *(*bdrv_aio_readv)(BlockDriverState *bs,
 147         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 148         BlockDriverCompletionFunc *cb, void *opaque);
 149     BlockDriverAIOCB *(*bdrv_aio_writev)(BlockDriverState *bs,
 150         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 151         BlockDriverCompletionFunc *cb, void *opaque);
 152     BlockDriverAIOCB *(*bdrv_aio_flush)(BlockDriverState *bs,
 153         BlockDriverCompletionFunc *cb, void *opaque);
 154     BlockDriverAIOCB *(*bdrv_aio_discard)(BlockDriverState *bs,
 155         int64_t sector_num, int nb_sectors,
 156         BlockDriverCompletionFunc *cb, void *opaque);
 157
 158     int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs,
 159         int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
 160     int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs,
 161         int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
 162     /*
 163      * Efficiently zero a region of the disk image.  Typically an image format
 164      * would use a compact metadata representation to implement this.  This
 165      * function pointer may be NULL and .bdrv_co_writev() will be called
 166      * instead.
 167      */
 168     int coroutine_fn (*bdrv_co_write_zeroes)(BlockDriverState *bs,
 169         int64_t sector_num, int nb_sectors);
 170     int coroutine_fn (*bdrv_co_discard)(BlockDriverState *bs,
 171         int64_t sector_num, int nb_sectors);
 172     int coroutine_fn (*bdrv_co_is_allocated)(BlockDriverState *bs,
 173         int64_t sector_num, int nb_sectors, int *pnum);
 174
 175     /*
 176      * Invalidate any cached meta-data.
 177      */
 178     void (*bdrv_invalidate_cache)(BlockDriverState *bs);
 179
 180     /*
 181      * Flushes all data that was already written to the OS all the way down to
 182      * the disk (for example raw-posix calls fsync()).
 183      */
 184     int coroutine_fn (*bdrv_co_flush_to_disk)(BlockDriverState *bs);
 185
 186     /*
 187      * Flushes all internal caches to the OS. The data may still sit in a
 188      * writeback cache of the host OS, but it will survive a crash of the qemu
 189      * process.
 190      */
 191     int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs);
 192
 193     const char *protocol_name;
 194     int (*bdrv_truncate)(BlockDriverState *bs, int64_t offset);
 195     int64_t (*bdrv_getlength)(BlockDriverState *bs);
 196     int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs);
 197     int (*bdrv_write_compressed)(BlockDriverState *bs, int64_t sector_num,
 198                                  const uint8_t *buf, int nb_sectors);
 199
 200     int (*bdrv_snapshot_create)(BlockDriverState *bs,
 201                                 QEMUSnapshotInfo *sn_info);
 202     int (*bdrv_snapshot_goto)(BlockDriverState *bs,
 203                               const char *snapshot_id);
 204     int (*bdrv_snapshot_delete)(BlockDriverState *bs, const char *snapshot_id);
 205     int (*bdrv_snapshot_list)(BlockDriverState *bs,
 206                               QEMUSnapshotInfo **psn_info);
 207     int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs,
 208                                   const char *snapshot_name);
 209     int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi);
 210
 211     int (*bdrv_save_vmstate)(BlockDriverState *bs, const uint8_t *buf,
 212                              int64_t pos, int size);
 213     int (*bdrv_load_vmstate)(BlockDriverState *bs, uint8_t *buf,
 214                              int64_t pos, int size);
 215
 216     int (*bdrv_change_backing_file)(BlockDriverState *bs,
 217         const char *backing_file, const char *backing_fmt);
 218
 219     /* removable device specific */
 220     int (*bdrv_is_inserted)(BlockDriverState *bs);
 221     int (*bdrv_media_changed)(BlockDriverState *bs);
 222     void (*bdrv_eject)(BlockDriverState *bs, bool eject_flag);
 223     void (*bdrv_lock_medium)(BlockDriverState *bs, bool locked);
 224
 225     /* to control generic scsi devices */
 226     int (*bdrv_ioctl)(BlockDriverState *bs, unsigned long int req, void *buf);
 227     BlockDriverAIOCB *(*bdrv_aio_ioctl)(BlockDriverState *bs,
 228         unsigned long int req, void *buf,
 229         BlockDriverCompletionFunc *cb, void *opaque);
 230
 231     /* List of options for creating images, terminated by name == NULL */
 232     QEMUOptionParameter *create_options;
 233
 234
 235     /*
 236      * Returns 0 for completed check, -errno for internal errors.
 237      * The check results are stored in result.
 238      */
 239     int (*bdrv_check)(BlockDriverState* bs, BdrvCheckResult *result);
 240
 241     void (*bdrv_debug_event)(BlockDriverState *bs, BlkDebugEvent event);
 242
 243     /*
 244      * Returns 1 if newly created images are guaranteed to contain only
 245      * zeros, 0 otherwise.
 246      */
 247     int (*bdrv_has_zero_init)(BlockDriverState *bs);
 248
 249     QLIST_ENTRY(BlockDriver) list;
 250 };
 251
 252 /*
 253  * Note: the function bdrv_append() copies and swaps contents of
 254  * BlockDriverStates, so if you add new fields to this struct, please
 255  * inspect bdrv_append() to determine if the new fields need to be
 256  * copied as well.
 257  */
 258 struct BlockDriverState {
 259     int64_t total_sectors; /* if we are reading a disk image, give its
 260                               size in sectors */
 261     int read_only; /* if true, the media is read only */
 262     int keep_read_only; /* if true, the media was requested to stay read only */
 263     int open_flags; /* flags used to open the file, re-used for re-open */
 264     int encrypted; /* if true, the media is encrypted */
 265     int valid_key; /* if true, a valid encryption key has been set */
 266     int sg;        /* if true, the device is a /dev/sg* */
 267     int copy_on_read; /* if true, copy read backing sectors into image
 268                          note this is a reference count */
 269
 270     BlockDriver *drv; /* NULL means no media */
 271     void *opaque;
 272
 273     void *dev;                  /* attached device model, if any */
 274     /* TODO change to DeviceState when all users are qdevified */
 275     const BlockDevOps *dev_ops;
 276     void *dev_opaque;
 277
 278     char filename[1024];
 279     char backing_file[1024]; /* if non zero, the image is a diff of
 280                                 this file image */
 281     char backing_format[16]; /* if non-zero and backing_file exists */
 282     int is_temporary;
 283
 284     BlockDriverState *backing_hd;
 285     BlockDriverState *file;
 286
 287     /* number of in-flight copy-on-read requests */
 288     unsigned int copy_on_read_in_flight;
 289
 290     /* the time for latest disk I/O */
 291     int64_t slice_time;
 292     int64_t slice_start;
 293     int64_t slice_end;
 294     BlockIOLimit io_limits;
 295     BlockIOBaseValue  io_base;
 296     CoQueue      throttled_reqs;
 297     QEMUTimer    *block_timer;
 298     bool         io_limits_enabled;
 299
 300     /* I/O stats (display with "info blockstats"). */
 301     uint64_t nr_bytes[BDRV_MAX_IOTYPE];
 302     uint64_t nr_ops[BDRV_MAX_IOTYPE];
 303     uint64_t total_time_ns[BDRV_MAX_IOTYPE];
 304     uint64_t wr_highest_sector;
 305
 306     /* Whether the disk can expand beyond total_sectors */
 307     int growable;
 308
 309     /* the memory alignment required for the buffers handled by this driver */
 310     int buffer_alignment;
 311
 312     /* do we need to tell the quest if we have a volatile write cache? */
 313     int enable_write_cache;
 314
 315     /* NOTE: the following infos are only hints for real hardware
 316        drivers. They are not used by the block driver */
 317     int cyls, heads, secs, translation;
 318     BlockErrorAction on_read_error, on_write_error;
 319     bool iostatus_enabled;
 320     BlockDeviceIoStatus iostatus;
 321     char device_name[32];
 322     unsigned long *dirty_bitmap;
 323     int64_t dirty_count;
 324     int in_use; /* users other than guest access, eg. block migration */
 325     QTAILQ_ENTRY(BlockDriverState) list;
 326
 327     QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;
 328
 329     /* long-running background operation */
 330     BlockJob *job;
 331 };
 332
 333 void get_tmp_filename(char *filename, int size);
 334
 335 void bdrv_set_io_limits(BlockDriverState *bs,
 336                         BlockIOLimit *io_limits);
 337
 338 #ifdef _WIN32
 339 int is_windows_drive(const char *filename);
 340 #endif
 341
 342 /**
 343  * block_job_create:
 344  * @job_type: The class object for the newly-created job.
 345  * @bs: The block
 346  * @cb: Completion function for the job.
 347  * @opaque: Opaque pointer value passed to @cb.
 348  *
 349  * Create a new long-running block device job and return it.  The job
 350  * will call @cb asynchronously when the job completes.  Note that
 351  * @bs may have been closed at the time the @cb it is called.  If
 352  * this is the case, the job may be reported as either cancelled or
 353  * completed.
 354  *
 355  * This function is not part of the public job interface; it should be
 356  * called from a wrapper that is specific to the job type.
 357  */
 358 void *block_job_create(const BlockJobType *job_type, BlockDriverState *bs,
 359                        BlockDriverCompletionFunc *cb, void *opaque);
 360
 361 /**
 362  * block_job_complete:
 363  * @job: The job being completed.
 364  * @ret: The status code.
 365  *
 366  * Call the completion function that was registered at creation time, and
 367  * free @job.
 368  */
 369 void block_job_complete(BlockJob *job, int ret);
 370
 371 /**
 372  * block_job_set_speed:
 373  * @job: The job to set the speed for.
 374  * @speed: The new value
 375  *
 376  * Set a rate-limiting parameter for the job; the actual meaning may
 377  * vary depending on the job type.
 378  */
 379 int block_job_set_speed(BlockJob *job, int64_t value);
 380
 381 /**
 382  * block_job_cancel:
 383  * @job: The job to be canceled.
 384  *
 385  * Asynchronously cancel the specified job.
 386  */
 387 void block_job_cancel(BlockJob *job);
 388
 389 /**
 390  * block_job_is_cancelled:
 391  * @job: The job being queried.
 392  *
 393  * Returns whether the job is scheduled for cancellation.
 394  */
 395 bool block_job_is_cancelled(BlockJob *job);
 396
 397 /**
 398  * block_job_cancel:
 399  * @job: The job to be canceled.
 400  *
 401  * Asynchronously cancel the job and wait for it to reach a quiescent
 402  * state.  Note that the completion callback will still be called
 403  * asynchronously, hence it is *not* valid to call #bdrv_delete
 404  * immediately after #block_job_cancel_sync.  Users of block jobs
 405  * will usually protect the BlockDriverState objects with a reference
 406  * count, should this be a concern.
 407  */
 408 void block_job_cancel_sync(BlockJob *job);
 409
 410 /**
 411  * stream_start:
 412  * @bs: Block device to operate on.
 413  * @base: Block device that will become the new base, or %NULL to
 414  * flatten the whole backing file chain onto @bs.
 415  * @base_id: The file name that will be written to @bs as the new
 416  * backing file if the job completes.  Ignored if @base is %NULL.
 417  * @cb: Completion function for the job.
 418  * @opaque: Opaque pointer value passed to @cb.
 419  *
 420  * Start a streaming operation on @bs.  Clusters that are unallocated
 421  * in @bs, but allocated in any image between @base and @bs (both
 422  * exclusive) will be written to @bs.  At the end of a successful
 423  * streaming job, the backing file of @bs will be changed to
 424  * @base_id in the written image and to @base in the live BlockDriverState.
 425  */
 426 int stream_start(BlockDriverState *bs, BlockDriverState *base,
 427                  const char *base_id, BlockDriverCompletionFunc *cb,
 428                  void *opaque);
 429
 430 #endif /* BLOCK_INT_H */