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