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