include/block/blockjob.h

   1 /*
   2  * Declarations for long-running block device operations
   3  *
   4  * Copyright (c) 2011 IBM Corp.
   5  * Copyright (c) 2012 Red Hat, Inc.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  */
  25
  26 #ifndef BLOCKJOB_H
  27 #define BLOCKJOB_H
  28
  29 #include "block/block.h"
  30 #include "qemu/ratelimit.h"
  31
  32 #define BLOCK_JOB_SLICE_TIME 100000000ULL /* ns */
  33
  34 typedef struct BlockJobDriver BlockJobDriver;
  35 typedef struct BlockJobTxn BlockJobTxn;
  36
  37 /**
  38  * BlockJob:
  39  *
  40  * Long-running operation on a BlockDriverState.
  41  */
  42 typedef struct BlockJob {
  43     /** The job type, including the job vtable.  */
  44     const BlockJobDriver *driver;
  45
  46     /** The block device on which the job is operating.  */
  47     BlockBackend *blk;
  48
  49     /**
  50      * The ID of the block job. May be NULL for internal jobs.
  51      */
  52     char *id;
  53
  54     /**
  55      * The coroutine that executes the job.  If not NULL, it is
  56      * reentered when busy is false and the job is cancelled.
  57      */
  58     Coroutine *co;
  59
  60     /**
  61      * Set to true if the job should cancel itself.  The flag must
  62      * always be tested just before toggling the busy flag from false
  63      * to true.  After a job has been cancelled, it should only yield
  64      * if #aio_poll will ("sooner or later") reenter the coroutine.
  65      */
  66     bool cancelled;
  67
  68     /**
  69      * Set to true if the job should abort immediately without waiting
  70      * for data to be in sync.
  71      */
  72     bool force;
  73
  74     /**
  75      * Counter for pause request. If non-zero, the block job is either paused,
  76      * or if busy == true will pause itself as soon as possible.
  77      */
  78     int pause_count;
  79
  80     /**
  81      * Set to true if the job is paused by user.  Can be unpaused with the
  82      * block-job-resume QMP command.
  83      */
  84     bool user_paused;
  85
  86     /**
  87      * Set to false by the job while the coroutine has yielded and may be
  88      * re-entered by block_job_enter().  There may still be I/O or event loop
  89      * activity pending.  Accessed under block_job_mutex (in blockjob.c).
  90      */
  91     bool busy;
  92
  93     /**
  94      * Set to true by the job while it is in a quiescent state, where
  95      * no I/O or event loop activity is pending.
  96      */
  97     bool paused;
  98
  99     /**
 100      * Set to true when the job is ready to be completed.
 101      */
 102     bool ready;
 103
 104     /**
 105      * Set to true when the job has deferred work to the main loop.
 106      */
 107     bool deferred_to_main_loop;
 108
 109     /** Element of the list of block jobs */
 110     QLIST_ENTRY(BlockJob) job_list;
 111
 112     /** Status that is published by the query-block-jobs QMP API */
 113     BlockDeviceIoStatus iostatus;
 114
 115     /** Offset that is published by the query-block-jobs QMP API */
 116     int64_t offset;
 117
 118     /** Length that is published by the query-block-jobs QMP API */
 119     int64_t len;
 120
 121     /** Speed that was set with @block_job_set_speed.  */
 122     int64_t speed;
 123
 124     /** Rate limiting data structure for implementing @speed. */
 125     RateLimit limit;
 126
 127     /** The completion function that will be called when the job completes.  */
 128     BlockCompletionFunc *cb;
 129
 130     /** Block other operations when block job is running */
 131     Error *blocker;
 132
 133     /** BlockDriverStates that are involved in this block job */
 134     GSList *nodes;
 135
 136     /** The opaque value that is passed to the completion function.  */
 137     void *opaque;
 138
 139     /** Reference count of the block job */
 140     int refcnt;
 141
 142     /** True when job has reported completion by calling block_job_completed. */
 143     bool completed;
 144
 145     /** ret code passed to block_job_completed. */
 146     int ret;
 147
 148     /**
 149      * Timer that is used by @block_job_sleep_ns. Accessed under
 150      * block_job_mutex (in blockjob.c).
 151      */
 152     QEMUTimer sleep_timer;
 153
 154     /** Current state; See @BlockJobStatus for details. */
 155     BlockJobStatus status;
 156
 157     /** True if this job should automatically finalize itself */
 158     bool auto_finalize;
 159
 160     /** True if this job should automatically dismiss itself */
 161     bool auto_dismiss;
 162
 163     BlockJobTxn *txn;
 164     QLIST_ENTRY(BlockJob) txn_list;
 165 } BlockJob;
 166
 167 typedef enum BlockJobCreateFlags {
 168     /* Default behavior */
 169     BLOCK_JOB_DEFAULT = 0x00,
 170     /* BlockJob is not QMP-created and should not send QMP events */
 171     BLOCK_JOB_INTERNAL = 0x01,
 172     /* BlockJob requires manual finalize step */
 173     BLOCK_JOB_MANUAL_FINALIZE = 0x02,
 174     /* BlockJob requires manual dismiss step */
 175     BLOCK_JOB_MANUAL_DISMISS = 0x04,
 176 } BlockJobCreateFlags;
 177
 178 /**
 179  * block_job_next:
 180  * @job: A block job, or %NULL.
 181  *
 182  * Get the next element from the list of block jobs after @job, or the
 183  * first one if @job is %NULL.
 184  *
 185  * Returns the requested job, or %NULL if there are no more jobs left.
 186  */
 187 BlockJob *block_job_next(BlockJob *job);
 188
 189 /**
 190  * block_job_get:
 191  * @id: The id of the block job.
 192  *
 193  * Get the block job identified by @id (which must not be %NULL).
 194  *
 195  * Returns the requested job, or %NULL if it doesn't exist.
 196  */
 197 BlockJob *block_job_get(const char *id);
 198
 199 /**
 200  * block_job_add_bdrv:
 201  * @job: A block job
 202  * @name: The name to assign to the new BdrvChild
 203  * @bs: A BlockDriverState that is involved in @job
 204  * @perm, @shared_perm: Permissions to request on the node
 205  *
 206  * Add @bs to the list of BlockDriverState that are involved in
 207  * @job. This means that all operations will be blocked on @bs while
 208  * @job exists.
 209  */
 210 int block_job_add_bdrv(BlockJob *job, const char *name, BlockDriverState *bs,
 211                        uint64_t perm, uint64_t shared_perm, Error **errp);
 212
 213 /**
 214  * block_job_remove_all_bdrv:
 215  * @job: The block job
 216  *
 217  * Remove all BlockDriverStates from the list of nodes that are involved in the
 218  * job. This removes the blockers added with block_job_add_bdrv().
 219  */
 220 void block_job_remove_all_bdrv(BlockJob *job);
 221
 222 /**
 223  * block_job_set_speed:
 224  * @job: The job to set the speed for.
 225  * @speed: The new value
 226  * @errp: Error object.
 227  *
 228  * Set a rate-limiting parameter for the job; the actual meaning may
 229  * vary depending on the job type.
 230  */
 231 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp);
 232
 233 /**
 234  * block_job_start:
 235  * @job: A job that has not yet been started.
 236  *
 237  * Begins execution of a block job.
 238  * Takes ownership of one reference to the job object.
 239  */
 240 void block_job_start(BlockJob *job);
 241
 242 /**
 243  * block_job_cancel:
 244  * @job: The job to be canceled.
 245  * @force: Quit a job without waiting for data to be in sync.
 246  *
 247  * Asynchronously cancel the specified job.
 248  */
 249 void block_job_cancel(BlockJob *job, bool force);
 250
 251 /**
 252  * block_job_complete:
 253  * @job: The job to be completed.
 254  * @errp: Error object.
 255  *
 256  * Asynchronously complete the specified job.
 257  */
 258 void block_job_complete(BlockJob *job, Error **errp);
 259
 260
 261 /**
 262  * block_job_finalize:
 263  * @job: The job to fully commit and finish.
 264  * @errp: Error object.
 265  *
 266  * For jobs that have finished their work and are pending
 267  * awaiting explicit acknowledgement to commit their work,
 268  * This will commit that work.
 269  *
 270  * FIXME: Make the below statement universally true:
 271  * For jobs that support the manual workflow mode, all graph
 272  * changes that occur as a result will occur after this command
 273  * and before a successful reply.
 274  */
 275 void block_job_finalize(BlockJob *job, Error **errp);
 276
 277 /**
 278  * block_job_dismiss:
 279  * @job: The job to be dismissed.
 280  * @errp: Error object.
 281  *
 282  * Remove a concluded job from the query list.
 283  */
 284 void block_job_dismiss(BlockJob **job, Error **errp);
 285
 286 /**
 287  * block_job_progress_update:
 288  * @job: The job that has made progress
 289  * @done: How much progress the job made
 290  *
 291  * Updates the progress counter of the job.
 292  */
 293 void block_job_progress_update(BlockJob *job, uint64_t done);
 294
 295 /**
 296  * block_job_progress_set_remaining:
 297  * @job: The job whose expected progress end value is set
 298  * @remaining: Expected end value of the progress counter of the job
 299  *
 300  * Sets the expected end value of the progress counter of a job so that a
 301  * completion percentage can be calculated when the progress is updated.
 302  */
 303 void block_job_progress_set_remaining(BlockJob *job, uint64_t remaining);
 304
 305 /**
 306  * block_job_query:
 307  * @job: The job to get information about.
 308  *
 309  * Return information about a job.
 310  */
 311 BlockJobInfo *block_job_query(BlockJob *job, Error **errp);
 312
 313 /**
 314  * block_job_user_pause:
 315  * @job: The job to be paused.
 316  *
 317  * Asynchronously pause the specified job.
 318  * Do not allow a resume until a matching call to block_job_user_resume.
 319  */
 320 void block_job_user_pause(BlockJob *job, Error **errp);
 321
 322 /**
 323  * block_job_paused:
 324  * @job: The job to query.
 325  *
 326  * Returns true if the job is user-paused.
 327  */
 328 bool block_job_user_paused(BlockJob *job);
 329
 330 /**
 331  * block_job_user_resume:
 332  * @job: The job to be resumed.
 333  *
 334  * Resume the specified job.
 335  * Must be paired with a preceding block_job_user_pause.
 336  */
 337 void block_job_user_resume(BlockJob *job, Error **errp);
 338
 339 /**
 340  * block_job_user_cancel:
 341  * @job: The job to be cancelled.
 342  * @force: Quit a job without waiting for data to be in sync.
 343  *
 344  * Cancels the specified job, but may refuse to do so if the
 345  * operation isn't currently meaningful.
 346  */
 347 void block_job_user_cancel(BlockJob *job, bool force, Error **errp);
 348
 349 /**
 350  * block_job_cancel_sync:
 351  * @job: The job to be canceled.
 352  *
 353  * Synchronously cancel the job.  The completion callback is called
 354  * before the function returns.  The job may actually complete
 355  * instead of canceling itself; the circumstances under which this
 356  * happens depend on the kind of job that is active.
 357  *
 358  * Returns the return value from the job if the job actually completed
 359  * during the call, or -ECANCELED if it was canceled.
 360  */
 361 int block_job_cancel_sync(BlockJob *job);
 362
 363 /**
 364  * block_job_cancel_sync_all:
 365  *
 366  * Synchronously cancels all jobs using block_job_cancel_sync().
 367  */
 368 void block_job_cancel_sync_all(void);
 369
 370 /**
 371  * block_job_complete_sync:
 372  * @job: The job to be completed.
 373  * @errp: Error object which may be set by block_job_complete(); this is not
 374  *        necessarily set on every error, the job return value has to be
 375  *        checked as well.
 376  *
 377  * Synchronously complete the job.  The completion callback is called before the
 378  * function returns, unless it is NULL (which is permissible when using this
 379  * function).
 380  *
 381  * Returns the return value from the job.
 382  */
 383 int block_job_complete_sync(BlockJob *job, Error **errp);
 384
 385 /**
 386  * block_job_iostatus_reset:
 387  * @job: The job whose I/O status should be reset.
 388  *
 389  * Reset I/O status on @job and on BlockDriverState objects it uses,
 390  * other than job->blk.
 391  */
 392 void block_job_iostatus_reset(BlockJob *job);
 393
 394 /**
 395  * block_job_txn_new:
 396  *
 397  * Allocate and return a new block job transaction.  Jobs can be added to the
 398  * transaction using block_job_txn_add_job().
 399  *
 400  * The transaction is automatically freed when the last job completes or is
 401  * cancelled.
 402  *
 403  * All jobs in the transaction either complete successfully or fail/cancel as a
 404  * group.  Jobs wait for each other before completing.  Cancelling one job
 405  * cancels all jobs in the transaction.
 406  */
 407 BlockJobTxn *block_job_txn_new(void);
 408
 409 /**
 410  * block_job_ref:
 411  *
 412  * Add a reference to BlockJob refcnt, it will be decreased with
 413  * block_job_unref, and then be freed if it comes to be the last
 414  * reference.
 415  */
 416 void block_job_ref(BlockJob *job);
 417
 418 /**
 419  * block_job_unref:
 420  *
 421  * Release a reference that was previously acquired with block_job_ref
 422  * or block_job_create. If it's the last reference to the object, it will be
 423  * freed.
 424  */
 425 void block_job_unref(BlockJob *job);
 426
 427 /**
 428  * block_job_txn_unref:
 429  *
 430  * Release a reference that was previously acquired with block_job_txn_add_job
 431  * or block_job_txn_new. If it's the last reference to the object, it will be
 432  * freed.
 433  */
 434 void block_job_txn_unref(BlockJobTxn *txn);
 435
 436 /**
 437  * block_job_txn_add_job:
 438  * @txn: The transaction (may be NULL)
 439  * @job: Job to add to the transaction
 440  *
 441  * Add @job to the transaction.  The @job must not already be in a transaction.
 442  * The caller must call either block_job_txn_unref() or block_job_completed()
 443  * to release the reference that is automatically grabbed here.
 444  */
 445 void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job);
 446
 447 /**
 448  * block_job_is_internal:
 449  * @job: The job to determine if it is user-visible or not.
 450  *
 451  * Returns true if the job should not be visible to the management layer.
 452  */
 453 bool block_job_is_internal(BlockJob *job);
 454
 455 /**
 456  * block_job_driver:
 457  *
 458  * Returns the driver associated with a block job.
 459  */
 460 const BlockJobDriver *block_job_driver(BlockJob *job);
 461
 462 #endif