1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
|
/*
* Common block export infrastructure
*
* Copyright (c) 2012, 2020 Red Hat, Inc.
*
* Authors:
* Paolo Bonzini <pbonzini@redhat.com>
* Kevin Wolf <kwolf@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* later. See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "block/block.h"
#include "sysemu/block-backend.h"
#include "block/export.h"
#include "block/nbd.h"
#include "qapi/error.h"
#include "qapi/qapi-commands-block-export.h"
#include "qapi/qapi-events-block-export.h"
#include "qemu/id.h"
static const BlockExportDriver *blk_exp_drivers[] = {
&blk_exp_nbd,
};
/* Only accessed from the main thread */
static QLIST_HEAD(, BlockExport) block_exports =
QLIST_HEAD_INITIALIZER(block_exports);
BlockExport *blk_exp_find(const char *id)
{
BlockExport *exp;
QLIST_FOREACH(exp, &block_exports, next) {
if (strcmp(id, exp->id) == 0) {
return exp;
}
}
return NULL;
}
static const BlockExportDriver *blk_exp_find_driver(BlockExportType type)
{
int i;
for (i = 0; i < ARRAY_SIZE(blk_exp_drivers); i++) {
if (blk_exp_drivers[i]->type == type) {
return blk_exp_drivers[i];
}
}
return NULL;
}
BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp)
{
const BlockExportDriver *drv;
BlockExport *exp;
int ret;
if (!id_wellformed(export->id)) {
error_setg(errp, "Invalid block export id");
return NULL;
}
if (blk_exp_find(export->id)) {
error_setg(errp, "Block export id '%s' is already in use", export->id);
return NULL;
}
drv = blk_exp_find_driver(export->type);
if (!drv) {
error_setg(errp, "No driver found for the requested export type");
return NULL;
}
assert(drv->instance_size >= sizeof(BlockExport));
exp = g_malloc0(drv->instance_size);
*exp = (BlockExport) {
.drv = drv,
.refcount = 1,
.user_owned = true,
.id = g_strdup(export->id),
};
ret = drv->create(exp, export, errp);
if (ret < 0) {
g_free(exp->id);
g_free(exp);
return NULL;
}
assert(exp->blk != NULL);
QLIST_INSERT_HEAD(&block_exports, exp, next);
return exp;
}
/* Callers must hold exp->ctx lock */
void blk_exp_ref(BlockExport *exp)
{
assert(exp->refcount > 0);
exp->refcount++;
}
/* Runs in the main thread */
static void blk_exp_delete_bh(void *opaque)
{
BlockExport *exp = opaque;
AioContext *aio_context = exp->ctx;
aio_context_acquire(aio_context);
assert(exp->refcount == 0);
QLIST_REMOVE(exp, next);
exp->drv->delete(exp);
blk_unref(exp->blk);
qapi_event_send_block_export_deleted(exp->id);
g_free(exp->id);
g_free(exp);
aio_context_release(aio_context);
}
/* Callers must hold exp->ctx lock */
void blk_exp_unref(BlockExport *exp)
{
assert(exp->refcount > 0);
if (--exp->refcount == 0) {
/* Touch the block_exports list only in the main thread */
aio_bh_schedule_oneshot(qemu_get_aio_context(), blk_exp_delete_bh,
exp);
}
}
/*
* Drops the user reference to the export and requests that all client
* connections and other internally held references start to shut down. When
* the function returns, there may still be active references while the export
* is in the process of shutting down.
*
* Acquires exp->ctx internally. Callers must *not* hold the lock.
*/
void blk_exp_request_shutdown(BlockExport *exp)
{
AioContext *aio_context = exp->ctx;
aio_context_acquire(aio_context);
/*
* If the user doesn't own the export any more, it is already shutting
* down. We must not call .request_shutdown and decrease the refcount a
* second time.
*/
if (!exp->user_owned) {
goto out;
}
exp->drv->request_shutdown(exp);
assert(exp->user_owned);
exp->user_owned = false;
blk_exp_unref(exp);
out:
aio_context_release(aio_context);
}
/*
* Returns whether a block export of the given type exists.
* type == BLOCK_EXPORT_TYPE__MAX checks for an export of any type.
*/
static bool blk_exp_has_type(BlockExportType type)
{
BlockExport *exp;
if (type == BLOCK_EXPORT_TYPE__MAX) {
return !QLIST_EMPTY(&block_exports);
}
QLIST_FOREACH(exp, &block_exports, next) {
if (exp->drv->type == type) {
return true;
}
}
return false;
}
/* type == BLOCK_EXPORT_TYPE__MAX for all types */
void blk_exp_close_all_type(BlockExportType type)
{
BlockExport *exp, *next;
assert(in_aio_context_home_thread(qemu_get_aio_context()));
QLIST_FOREACH_SAFE(exp, &block_exports, next, next) {
if (type != BLOCK_EXPORT_TYPE__MAX && exp->drv->type != type) {
continue;
}
blk_exp_request_shutdown(exp);
}
AIO_WAIT_WHILE(NULL, blk_exp_has_type(type));
}
void blk_exp_close_all(void)
{
blk_exp_close_all_type(BLOCK_EXPORT_TYPE__MAX);
}
void qmp_block_export_add(BlockExportOptions *export, Error **errp)
{
blk_exp_add(export, errp);
}
void qmp_block_export_del(const char *id,
bool has_mode, BlockExportRemoveMode mode,
Error **errp)
{
ERRP_GUARD();
BlockExport *exp;
exp = blk_exp_find(id);
if (exp == NULL) {
error_setg(errp, "Export '%s' is not found", id);
return;
}
if (!exp->user_owned) {
error_setg(errp, "Export '%s' is already shutting down", id);
return;
}
if (!has_mode) {
mode = BLOCK_EXPORT_REMOVE_MODE_SAFE;
}
if (mode == BLOCK_EXPORT_REMOVE_MODE_SAFE && exp->refcount > 1) {
error_setg(errp, "export '%s' still in use", exp->id);
error_append_hint(errp, "Use mode='hard' to force client "
"disconnect\n");
return;
}
blk_exp_request_shutdown(exp);
}
|