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  * @name: The name to assign to the new BdrvChild
 173  * @bs: A BlockDriverState that is involved in @job
 174  * @perm, @shared_perm: Permissions to request on the node
 175  *
 176  * Add @bs to the list of BlockDriverState that are involved in
 177  * @job. This means that all operations will be blocked on @bs while
 178  * @job exists.
 179  */
 180 int block_job_add_bdrv(BlockJob *job, const char *name, BlockDriverState *bs,
 181                        uint64_t perm, uint64_t shared_perm, Error **errp);
 182
 183 /**
 184  * block_job_remove_all_bdrv:
 185  * @job: The block job
 186  *
 187  * Remove all BlockDriverStates from the list of nodes that are involved in the
 188  * job. This removes the blockers added with block_job_add_bdrv().
 189  */
 190 void block_job_remove_all_bdrv(BlockJob *job);
 191
 192 /**
 193  * block_job_set_speed:
 194  * @job: The job to set the speed for.
 195  * @speed: The new value
 196  * @errp: Error object.
 197  *
 198  * Set a rate-limiting parameter for the job; the actual meaning may
 199  * vary depending on the job type.
 200  */
 201 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp);
 202
 203 /**
 204  * block_job_start:
 205  * @job: A job that has not yet been started.
 206  *
 207  * Begins execution of a block job.
 208  * Takes ownership of one reference to the job object.
 209  */
 210 void block_job_start(BlockJob *job);
 211
 212 /**
 213  * block_job_cancel:
 214  * @job: The job to be canceled.
 215  *
 216  * Asynchronously cancel the specified job.
 217  */
 218 void block_job_cancel(BlockJob *job);
 219
 220 /**
 221  * block_job_complete:
 222  * @job: The job to be completed.
 223  * @errp: Error object.
 224  *
 225  * Asynchronously complete the specified job.
 226  */
 227 void block_job_complete(BlockJob *job, Error **errp);
 228
 229 /**
 230  * block_job_query:
 231  * @job: The job to get information about.
 232  *
 233  * Return information about a job.
 234  */
 235 BlockJobInfo *block_job_query(BlockJob *job, Error **errp);
 236
 237 /**
 238  * block_job_user_pause:
 239  * @job: The job to be paused.
 240  *
 241  * Asynchronously pause the specified job.
 242  * Do not allow a resume until a matching call to block_job_user_resume.
 243  */
 244 void block_job_user_pause(BlockJob *job);
 245
 246 /**
 247  * block_job_paused:
 248  * @job: The job to query.
 249  *
 250  * Returns true if the job is user-paused.
 251  */
 252 bool block_job_user_paused(BlockJob *job);
 253
 254 /**
 255  * block_job_user_resume:
 256  * @job: The job to be resumed.
 257  *
 258  * Resume the specified job.
 259  * Must be paired with a preceding block_job_user_pause.
 260  */
 261 void block_job_user_resume(BlockJob *job);
 262
 263 /**
 264  * block_job_cancel_sync:
 265  * @job: The job to be canceled.
 266  *
 267  * Synchronously cancel the job.  The completion callback is called
 268  * before the function returns.  The job may actually complete
 269  * instead of canceling itself; the circumstances under which this
 270  * happens depend on the kind of job that is active.
 271  *
 272  * Returns the return value from the job if the job actually completed
 273  * during the call, or -ECANCELED if it was canceled.
 274  */
 275 int block_job_cancel_sync(BlockJob *job);
 276
 277 /**
 278  * block_job_cancel_sync_all:
 279  *
 280  * Synchronously cancels all jobs using block_job_cancel_sync().
 281  */
 282 void block_job_cancel_sync_all(void);
 283
 284 /**
 285  * block_job_complete_sync:
 286  * @job: The job to be completed.
 287  * @errp: Error object which may be set by block_job_complete(); this is not
 288  *        necessarily set on every error, the job return value has to be
 289  *        checked as well.
 290  *
 291  * Synchronously complete the job.  The completion callback is called before the
 292  * function returns, unless it is NULL (which is permissible when using this
 293  * function).
 294  *
 295  * Returns the return value from the job.
 296  */
 297 int block_job_complete_sync(BlockJob *job, Error **errp);
 298
 299 /**
 300  * block_job_iostatus_reset:
 301  * @job: The job whose I/O status should be reset.
 302  *
 303  * Reset I/O status on @job and on BlockDriverState objects it uses,
 304  * other than job->blk.
 305  */
 306 void block_job_iostatus_reset(BlockJob *job);
 307
 308 /**
 309  * block_job_txn_new:
 310  *
 311  * Allocate and return a new block job transaction.  Jobs can be added to the
 312  * transaction using block_job_txn_add_job().
 313  *
 314  * The transaction is automatically freed when the last job completes or is
 315  * cancelled.
 316  *
 317  * All jobs in the transaction either complete successfully or fail/cancel as a
 318  * group.  Jobs wait for each other before completing.  Cancelling one job
 319  * cancels all jobs in the transaction.
 320  */
 321 BlockJobTxn *block_job_txn_new(void);
 322
 323 /**
 324  * block_job_ref:
 325  *
 326  * Add a reference to BlockJob refcnt, it will be decreased with
 327  * block_job_unref, and then be freed if it comes to be the last
 328  * reference.
 329  */
 330 void block_job_ref(BlockJob *job);
 331
 332 /**
 333  * block_job_unref:
 334  *
 335  * Release a reference that was previously acquired with block_job_ref
 336  * or block_job_create. If it's the last reference to the object, it will be
 337  * freed.
 338  */
 339 void block_job_unref(BlockJob *job);
 340
 341 /**
 342  * block_job_txn_unref:
 343  *
 344  * Release a reference that was previously acquired with block_job_txn_add_job
 345  * or block_job_txn_new. If it's the last reference to the object, it will be
 346  * freed.
 347  */
 348 void block_job_txn_unref(BlockJobTxn *txn);
 349
 350 /**
 351  * block_job_txn_add_job:
 352  * @txn: The transaction (may be NULL)
 353  * @job: Job to add to the transaction
 354  *
 355  * Add @job to the transaction.  The @job must not already be in a transaction.
 356  * The caller must call either block_job_txn_unref() or block_job_completed()
 357  * to release the reference that is automatically grabbed here.
 358  */
 359 void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job);
 360
 361 /**
 362  * block_job_is_internal:
 363  * @job: The job to determine if it is user-visible or not.
 364  *
 365  * Returns true if the job should not be visible to the management layer.
 366  */
 367 bool block_job_is_internal(BlockJob *job);
 368
 369 #endif