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