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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 #ifndef BLOCKJOB_H
26 #define BLOCKJOB_H 1
27
28 #include "block.h"
29
30 /**
31 * BlockJobType:
32 *
33 * A class type for block job objects.
34 */
35 typedef struct BlockJobType {
36 /** Derived BlockJob struct size */
37 size_t instance_size;
38
39 /** String describing the operation, part of query-block-jobs QMP API */
40 const char *job_type;
41
42 /** Optional callback for job types that support setting a speed limit */
43 void (*set_speed)(BlockJob *job, int64_t speed, Error **errp);
44 } BlockJobType;
45
46 /**
47 * BlockJob:
48 *
49 * Long-running operation on a BlockDriverState.
50 */
51 struct BlockJob {
52 /** The job type, including the job vtable. */
53 const BlockJobType *job_type;
54
55 /** The block device on which the job is operating. */
56 BlockDriverState *bs;
57
58 /**
59 * The coroutine that executes the job. If not NULL, it is
60 * reentered when busy is false and the job is cancelled.
61 */
62 Coroutine *co;
63
64 /**
65 * Set to true if the job should cancel itself. The flag must
66 * always be tested just before toggling the busy flag from false
67 * to true. After a job has been cancelled, it should only yield
68 * if #qemu_aio_wait will ("sooner or later") reenter the coroutine.
69 */
70 bool cancelled;
71
72 /**
73 * Set to true if the job is either paused, or will pause itself
74 * as soon as possible (if busy == true).
75 */
76 bool paused;
77
78 /**
79 * Set to false by the job while it is in a quiescent state, where
80 * no I/O is pending and the job has yielded on any condition
81 * that is not detected by #qemu_aio_wait, such as a timer.
82 */
83 bool busy;
84
85 /** Status that is published by the query-block-jobs QMP API */
86 BlockDeviceIoStatus iostatus;
87
88 /** Offset that is published by the query-block-jobs QMP API */
89 int64_t offset;
90
91 /** Length that is published by the query-block-jobs QMP API */
92 int64_t len;
93
94 /** Speed that was set with @block_job_set_speed. */
95 int64_t speed;
96
97 /** The completion function that will be called when the job completes. */
98 BlockDriverCompletionFunc *cb;
99
100 /** The opaque value that is passed to the completion function. */
101 void *opaque;
102 };
103
104 /**
105 * block_job_create:
106 * @job_type: The class object for the newly-created job.
107 * @bs: The block
108 * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
109 * @cb: Completion function for the job.
110 * @opaque: Opaque pointer value passed to @cb.
111 * @errp: Error object.
112 *
113 * Create a new long-running block device job and return it. The job
114 * will call @cb asynchronously when the job completes. Note that
115 * @bs may have been closed at the time the @cb it is called. If
116 * this is the case, the job may be reported as either cancelled or
117 * completed.
118 *
119 * This function is not part of the public job interface; it should be
120 * called from a wrapper that is specific to the job type.
121 */
122 void *block_job_create(const BlockJobType *job_type, BlockDriverState *bs,
123 int64_t speed, BlockDriverCompletionFunc *cb,
124 void *opaque, Error **errp);
125
126 /**
127 * block_job_sleep_ns:
128 * @job: The job that calls the function.
129 * @clock: The clock to sleep on.
130 * @ns: How many nanoseconds to stop for.
131 *
132 * Put the job to sleep (assuming that it wasn't canceled) for @ns
133 * nanoseconds. Canceling the job will interrupt the wait immediately.
134 */
135 void block_job_sleep_ns(BlockJob *job, QEMUClock *clock, int64_t ns);
136
137 /**
138 * block_job_complete:
139 * @job: The job being completed.
140 * @ret: The status code.
141 *
142 * Call the completion function that was registered at creation time, and
143 * free @job.
144 */
145 void block_job_complete(BlockJob *job, int ret);
146
147 /**
148 * block_job_set_speed:
149 * @job: The job to set the speed for.
150 * @speed: The new value
151 * @errp: Error object.
152 *
153 * Set a rate-limiting parameter for the job; the actual meaning may
154 * vary depending on the job type.
155 */
156 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp);
157
158 /**
159 * block_job_cancel:
160 * @job: The job to be canceled.
161 *
162 * Asynchronously cancel the specified job.
163 */
164 void block_job_cancel(BlockJob *job);
165
166 /**
167 * block_job_is_cancelled:
168 * @job: The job being queried.
169 *
170 * Returns whether the job is scheduled for cancellation.
171 */
172 bool block_job_is_cancelled(BlockJob *job);
173
174 /**
175 * block_job_query:
176 * @job: The job to get information about.
177 *
178 * Return information about a job.
179 */
180 BlockJobInfo *block_job_query(BlockJob *job);
181
182 /**
183 * block_job_pause:
184 * @job: The job to be paused.
185 *
186 * Asynchronously pause the specified job.
187 */
188 void block_job_pause(BlockJob *job);
189
190 /**
191 * block_job_resume:
192 * @job: The job to be resumed.
193 *
194 * Resume the specified job.
195 */
196 void block_job_resume(BlockJob *job);
197
198 /**
199 * block_job_is_paused:
200 * @job: The job being queried.
201 *
202 * Returns whether the job is currently paused, or will pause
203 * as soon as it reaches a sleeping point.
204 */
205 bool block_job_is_paused(BlockJob *job);
206
207 /**
208 * block_job_cancel_sync:
209 * @job: The job to be canceled.
210 *
211 * Synchronously cancel the job. The completion callback is called
212 * before the function returns. The job may actually complete
213 * instead of canceling itself; the circumstances under which this
214 * happens depend on the kind of job that is active.
215 *
216 * Returns the return value from the job if the job actually completed
217 * during the call, or -ECANCELED if it was canceled.
218 */
219 int block_job_cancel_sync(BlockJob *job);
220
221 /**
222 * block_job_iostatus_reset:
223 * @job: The job whose I/O status should be reset.
224 *
225 * Reset I/O status on @job.
226 */
227 void block_job_iostatus_reset(BlockJob *job);
228
229 /**
230 * block_job_error_action:
231 * @job: The job to signal an error for.
232 * @bs: The block device on which to set an I/O error.
233 * @on_err: The error action setting.
234 * @is_read: Whether the operation was a read.
235 * @error: The error that was reported.
236 *
237 * Report an I/O error for a block job and possibly stop the VM. Return the
238 * action that was selected based on @on_err and @error.
239 */
240 BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs,
241 BlockdevOnError on_err,
242 int is_read, int error);
243 #endif