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.
  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 if this job has reported completion by calling block_job_completed.
 131      */
 132     bool completed;
 133
 134     /* ret code passed to block_job_completed.
 135      */
 136     int ret;
 137
 138     /** Non-NULL if this job is part of a transaction */
 139     BlockJobTxn *txn;
 140     QLIST_ENTRY(BlockJob) txn_list;
 141 } BlockJob;
 142
 143 typedef enum BlockJobCreateFlags {
 144     BLOCK_JOB_DEFAULT = 0x00,
 145     BLOCK_JOB_INTERNAL = 0x01,
 146 } BlockJobCreateFlags;
 147
 148 /**
 149  * block_job_next:
 150  * @job: A block job, or %NULL.
 151  *
 152  * Get the next element from the list of block jobs after @job, or the
 153  * first one if @job is %NULL.
 154  *
 155  * Returns the requested job, or %NULL if there are no more jobs left.
 156  */
 157 BlockJob *block_job_next(BlockJob *job);
 158
 159 /**
 160  * block_job_get:
 161  * @id: The id of the block job.
 162  *
 163  * Get the block job identified by @id (which must not be %NULL).
 164  *
 165  * Returns the requested job, or %NULL if it doesn't exist.
 166  */
 167 BlockJob *block_job_get(const char *id);
 168
 169 /**
 170  * block_job_add_bdrv:
 171  * @job: A block job
 172  * @bs: A BlockDriverState that is involved in @job
 173  *
 174  * Add @bs to the list of BlockDriverState that are involved in
 175  * @job. This means that all operations will be blocked on @bs while
 176  * @job exists.
 177  */
 178 void block_job_add_bdrv(BlockJob *job, BlockDriverState *bs);
 179
 180 /**
 181  * block_job_set_speed:
 182  * @job: The job to set the speed for.
 183  * @speed: The new value
 184  * @errp: Error object.
 185  *
 186  * Set a rate-limiting parameter for the job; the actual meaning may
 187  * vary depending on the job type.
 188  */
 189 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp);
 190
 191 /**
 192  * block_job_cancel:
 193  * @job: The job to be canceled.
 194  *
 195  * Asynchronously cancel the specified job.
 196  */
 197 void block_job_cancel(BlockJob *job);
 198
 199 /**
 200  * block_job_complete:
 201  * @job: The job to be completed.
 202  * @errp: Error object.
 203  *
 204  * Asynchronously complete the specified job.
 205  */
 206 void block_job_complete(BlockJob *job, Error **errp);
 207
 208 /**
 209  * block_job_query:
 210  * @job: The job to get information about.
 211  *
 212  * Return information about a job.
 213  */
 214 BlockJobInfo *block_job_query(BlockJob *job, Error **errp);
 215
 216 /**
 217  * block_job_pause:
 218  * @job: The job to be paused.
 219  *
 220  * Asynchronously pause the specified job.
 221  */
 222 void block_job_pause(BlockJob *job);
 223
 224 /**
 225  * block_job_user_pause:
 226  * @job: The job to be paused.
 227  *
 228  * Asynchronously pause the specified job.
 229  * Do not allow a resume until a matching call to block_job_user_resume.
 230  */
 231 void block_job_user_pause(BlockJob *job);
 232
 233 /**
 234  * block_job_paused:
 235  * @job: The job to query.
 236  *
 237  * Returns true if the job is user-paused.
 238  */
 239 bool block_job_user_paused(BlockJob *job);
 240
 241 /**
 242  * block_job_resume:
 243  * @job: The job to be resumed.
 244  *
 245  * Resume the specified job.  Must be paired with a preceding block_job_pause.
 246  */
 247 void block_job_resume(BlockJob *job);
 248
 249 /**
 250  * block_job_user_resume:
 251  * @job: The job to be resumed.
 252  *
 253  * Resume the specified job.
 254  * Must be paired with a preceding block_job_user_pause.
 255  */
 256 void block_job_user_resume(BlockJob *job);
 257
 258 /**
 259  * block_job_cancel_sync:
 260  * @job: The job to be canceled.
 261  *
 262  * Synchronously cancel the job.  The completion callback is called
 263  * before the function returns.  The job may actually complete
 264  * instead of canceling itself; the circumstances under which this
 265  * happens depend on the kind of job that is active.
 266  *
 267  * Returns the return value from the job if the job actually completed
 268  * during the call, or -ECANCELED if it was canceled.
 269  */
 270 int block_job_cancel_sync(BlockJob *job);
 271
 272 /**
 273  * block_job_cancel_sync_all:
 274  *
 275  * Synchronously cancels all jobs using block_job_cancel_sync().
 276  */
 277 void block_job_cancel_sync_all(void);
 278
 279 /**
 280  * block_job_complete_sync:
 281  * @job: The job to be completed.
 282  * @errp: Error object which may be set by block_job_complete(); this is not
 283  *        necessarily set on every error, the job return value has to be
 284  *        checked as well.
 285  *
 286  * Synchronously complete the job.  The completion callback is called before the
 287  * function returns, unless it is NULL (which is permissible when using this
 288  * function).
 289  *
 290  * Returns the return value from the job.
 291  */
 292 int block_job_complete_sync(BlockJob *job, Error **errp);
 293
 294 /**
 295  * block_job_iostatus_reset:
 296  * @job: The job whose I/O status should be reset.
 297  *
 298  * Reset I/O status on @job and on BlockDriverState objects it uses,
 299  * other than job->blk.
 300  */
 301 void block_job_iostatus_reset(BlockJob *job);
 302
 303 /**
 304  * block_job_txn_new:
 305  *
 306  * Allocate and return a new block job transaction.  Jobs can be added to the
 307  * transaction using block_job_txn_add_job().
 308  *
 309  * The transaction is automatically freed when the last job completes or is
 310  * cancelled.
 311  *
 312  * All jobs in the transaction either complete successfully or fail/cancel as a
 313  * group.  Jobs wait for each other before completing.  Cancelling one job
 314  * cancels all jobs in the transaction.
 315  */
 316 BlockJobTxn *block_job_txn_new(void);
 317
 318 /**
 319  * block_job_txn_unref:
 320  *
 321  * Release a reference that was previously acquired with block_job_txn_add_job
 322  * or block_job_txn_new. If it's the last reference to the object, it will be
 323  * freed.
 324  */
 325 void block_job_txn_unref(BlockJobTxn *txn);
 326
 327 /**
 328  * block_job_txn_add_job:
 329  * @txn: The transaction (may be NULL)
 330  * @job: Job to add to the transaction
 331  *
 332  * Add @job to the transaction.  The @job must not already be in a transaction.
 333  * The caller must call either block_job_txn_unref() or block_job_completed()
 334  * to release the reference that is automatically grabbed here.
 335  */
 336 void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job);
 337
 338 /**
 339  * block_job_is_internal:
 340  * @job: The job to determine if it is user-visible or not.
 341  *
 342  * Returns true if the job should not be visible to the management layer.
 343  */
 344 bool block_job_is_internal(BlockJob *job);
 345
 346 #endif