1 /*
2  * QEMU System Emulator block driver
3  *
4  * Copyright (c) 2003 Fabrice Bellard
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  */
24 #ifndef BLOCK_GLOBAL_STATE_H
25 #define BLOCK_GLOBAL_STATE_H
26 
27 #include "block/block-common.h"
28 #include "qemu/coroutine.h"
29 #include "qemu/transactions.h"
30 
31 /*
32  * Global state (GS) API. These functions run under the BQL.
33  *
34  * If a function modifies the graph, it also uses drain and/or
35  * aio_context_acquire/release to be sure it has unique access.
36  * aio_context locking is needed together with BQL because of
37  * the thread-safe I/O API that concurrently runs and accesses
38  * the graph without the BQL.
39  *
40  * It is important to note that not all of these functions are
41  * necessarily limited to running under the BQL, but they would
42  * require additional auditing and many small thread-safety changes
43  * to move them into the I/O API. Often it's not worth doing that
44  * work since the APIs are only used with the BQL held at the
45  * moment, so they have been placed in the GS API (for now).
46  *
47  * These functions can call any function from this and other categories
48  * (I/O, "I/O or GS", Common), but must be invoked only by other GS APIs.
49  *
50  * All functions in this header must use the macro
51  * GLOBAL_STATE_CODE();
52  * to catch when they are accidentally called without the BQL.
53  */
54 
55 void bdrv_init(void);
56 BlockDriver *bdrv_find_protocol(const char *filename,
57                                 bool allow_protocol_prefix,
58                                 Error **errp);
59 BlockDriver *bdrv_find_format(const char *format_name);
60 
61 int coroutine_fn GRAPH_UNLOCKED
62 bdrv_co_create(BlockDriver *drv, const char *filename, QemuOpts *opts,
63                Error **errp);
64 
65 int co_wrapper bdrv_create(BlockDriver *drv, const char *filename,
66                            QemuOpts *opts, Error **errp);
67 
68 int coroutine_fn GRAPH_UNLOCKED
69 bdrv_co_create_file(const char *filename, QemuOpts *opts, Error **errp);
70 
71 BlockDriverState *bdrv_new(void);
72 int bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
73                 Error **errp);
74 int bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
75                       Error **errp);
76 int bdrv_replace_child_bs(BdrvChild *child, BlockDriverState *new_bs,
77                           Error **errp);
78 BlockDriverState *bdrv_insert_node(BlockDriverState *bs, QDict *node_options,
79                                    int flags, Error **errp);
80 int bdrv_drop_filter(BlockDriverState *bs, Error **errp);
81 
82 BdrvChild * no_coroutine_fn
83 bdrv_open_child(const char *filename, QDict *options, const char *bdref_key,
84                 BlockDriverState *parent, const BdrvChildClass *child_class,
85                 BdrvChildRole child_role, bool allow_none, Error **errp);
86 
87 BdrvChild * coroutine_fn no_co_wrapper
88 bdrv_co_open_child(const char *filename, QDict *options, const char *bdref_key,
89                 BlockDriverState *parent, const BdrvChildClass *child_class,
90                 BdrvChildRole child_role, bool allow_none, Error **errp);
91 
92 int bdrv_open_file_child(const char *filename,
93                          QDict *options, const char *bdref_key,
94                          BlockDriverState *parent, Error **errp);
95 
96 BlockDriverState * no_coroutine_fn
97 bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp);
98 
99 BlockDriverState * coroutine_fn no_co_wrapper
100 bdrv_co_open_blockdev_ref(BlockdevRef *ref, Error **errp);
101 
102 int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
103                         Error **errp);
104 int bdrv_set_backing_hd_drained(BlockDriverState *bs,
105                                 BlockDriverState *backing_hd,
106                                 Error **errp);
107 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
108                            const char *bdref_key, Error **errp);
109 
110 BlockDriverState * no_coroutine_fn
111 bdrv_open(const char *filename, const char *reference, QDict *options,
112           int flags, Error **errp);
113 
114 BlockDriverState * coroutine_fn no_co_wrapper
115 bdrv_co_open(const char *filename, const char *reference,
116              QDict *options, int flags, Error **errp);
117 
118 BlockDriverState *bdrv_new_open_driver_opts(BlockDriver *drv,
119                                             const char *node_name,
120                                             QDict *options, int flags,
121                                             Error **errp);
122 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
123                                        int flags, Error **errp);
124 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
125                                     BlockDriverState *bs, QDict *options,
126                                     bool keep_old_opts);
127 void bdrv_reopen_queue_free(BlockReopenQueue *bs_queue);
128 int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp);
129 int bdrv_reopen(BlockDriverState *bs, QDict *opts, bool keep_old_opts,
130                 Error **errp);
131 int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
132                               Error **errp);
133 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
134                                           const char *backing_file);
135 void GRAPH_RDLOCK bdrv_refresh_filename(BlockDriverState *bs);
136 
137 void GRAPH_RDLOCK
138 bdrv_refresh_limits(BlockDriverState *bs, Transaction *tran, Error **errp);
139 
140 int bdrv_commit(BlockDriverState *bs);
141 int GRAPH_RDLOCK bdrv_make_empty(BdrvChild *c, Error **errp);
142 int bdrv_change_backing_file(BlockDriverState *bs, const char *backing_file,
143                              const char *backing_fmt, bool warn);
144 void bdrv_register(BlockDriver *bdrv);
145 int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
146                            const char *backing_file_str);
147 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
148                                     BlockDriverState *bs);
149 BlockDriverState *bdrv_find_base(BlockDriverState *bs);
150 bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base,
151                                   Error **errp);
152 int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base,
153                               Error **errp);
154 void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base);
155 
156 /*
157  * The units of offset and total_work_size may be chosen arbitrarily by the
158  * block driver; total_work_size may change during the course of the amendment
159  * operation
160  */
161 typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
162                                       int64_t total_work_size, void *opaque);
163 int GRAPH_RDLOCK
164 bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
165                    BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
166                    bool force, Error **errp);
167 
168 /* check if a named node can be replaced when doing drive-mirror */
169 BlockDriverState * GRAPH_RDLOCK
170 check_to_replace_node(BlockDriverState *parent_bs, const char *node_name,
171                       Error **errp);
172 
173 int no_coroutine_fn GRAPH_RDLOCK
174 bdrv_activate(BlockDriverState *bs, Error **errp);
175 
176 int coroutine_fn no_co_wrapper_bdrv_rdlock
177 bdrv_co_activate(BlockDriverState *bs, Error **errp);
178 
179 void bdrv_activate_all(Error **errp);
180 int bdrv_inactivate_all(void);
181 
182 int bdrv_flush_all(void);
183 void bdrv_close_all(void);
184 void bdrv_drain_all_begin(void);
185 void bdrv_drain_all_begin_nopoll(void);
186 void bdrv_drain_all_end(void);
187 void bdrv_drain_all(void);
188 
189 void bdrv_aio_cancel(BlockAIOCB *acb);
190 
191 int bdrv_has_zero_init_1(BlockDriverState *bs);
192 int coroutine_mixed_fn GRAPH_RDLOCK bdrv_has_zero_init(BlockDriverState *bs);
193 BlockDriverState *bdrv_find_node(const char *node_name);
194 BlockDeviceInfoList *bdrv_named_nodes_list(bool flat, Error **errp);
195 XDbgBlockGraph * GRAPH_RDLOCK bdrv_get_xdbg_block_graph(Error **errp);
196 BlockDriverState *bdrv_lookup_bs(const char *device,
197                                  const char *node_name,
198                                  Error **errp);
199 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
200 BlockDriverState *bdrv_next_node(BlockDriverState *bs);
201 BlockDriverState *bdrv_next_all_states(BlockDriverState *bs);
202 
203 typedef struct BdrvNextIterator {
204     enum {
205         BDRV_NEXT_BACKEND_ROOTS,
206         BDRV_NEXT_MONITOR_OWNED,
207     } phase;
208     BlockBackend *blk;
209     BlockDriverState *bs;
210 } BdrvNextIterator;
211 
212 BlockDriverState * GRAPH_RDLOCK bdrv_first(BdrvNextIterator *it);
213 BlockDriverState * GRAPH_RDLOCK bdrv_next(BdrvNextIterator *it);
214 void bdrv_next_cleanup(BdrvNextIterator *it);
215 
216 BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs);
217 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
218                          void *opaque, bool read_only);
219 
220 char * GRAPH_RDLOCK
221 bdrv_get_full_backing_filename(BlockDriverState *bs, Error **errp);
222 
223 char * GRAPH_RDLOCK bdrv_dirname(BlockDriverState *bs, Error **errp);
224 
225 void bdrv_img_create(const char *filename, const char *fmt,
226                      const char *base_filename, const char *base_fmt,
227                      char *options, uint64_t img_size, int flags,
228                      bool quiet, Error **errp);
229 
230 void bdrv_ref(BlockDriverState *bs);
231 void no_coroutine_fn bdrv_unref(BlockDriverState *bs);
232 void coroutine_fn no_co_wrapper bdrv_co_unref(BlockDriverState *bs);
233 void GRAPH_WRLOCK bdrv_schedule_unref(BlockDriverState *bs);
234 
235 void GRAPH_WRLOCK
236 bdrv_unref_child(BlockDriverState *parent, BdrvChild *child);
237 
238 void coroutine_fn no_co_wrapper_bdrv_wrlock
239 bdrv_co_unref_child(BlockDriverState *parent, BdrvChild *child);
240 
241 BdrvChild * GRAPH_WRLOCK
242 bdrv_attach_child(BlockDriverState *parent_bs,
243                   BlockDriverState *child_bs,
244                   const char *child_name,
245                   const BdrvChildClass *child_class,
246                   BdrvChildRole child_role,
247                   Error **errp);
248 
249 bool GRAPH_RDLOCK
250 bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
251 
252 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);
253 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason);
254 void bdrv_op_block_all(BlockDriverState *bs, Error *reason);
255 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason);
256 bool bdrv_op_blocker_is_empty(BlockDriverState *bs);
257 
258 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
259                            const char *tag);
260 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag);
261 int bdrv_debug_resume(BlockDriverState *bs, const char *tag);
262 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag);
263 
264 /**
265  * Locks the AioContext of @bs if it's not the current AioContext. This avoids
266  * double locking which could lead to deadlocks: This is a coroutine_fn, so we
267  * know we already own the lock of the current AioContext.
268  *
269  * May only be called in the main thread.
270  */
271 void coroutine_fn bdrv_co_lock(BlockDriverState *bs);
272 
273 /**
274  * Unlocks the AioContext of @bs if it's not the current AioContext.
275  */
276 void coroutine_fn bdrv_co_unlock(BlockDriverState *bs);
277 
278 bool bdrv_child_change_aio_context(BdrvChild *c, AioContext *ctx,
279                                    GHashTable *visited, Transaction *tran,
280                                    Error **errp);
281 int bdrv_try_change_aio_context(BlockDriverState *bs, AioContext *ctx,
282                                 BdrvChild *ignore_child, Error **errp);
283 
284 int GRAPH_RDLOCK bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
285 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
286 
287 void GRAPH_WRLOCK
288 bdrv_add_child(BlockDriverState *parent, BlockDriverState *child, Error **errp);
289 
290 void GRAPH_WRLOCK
291 bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
292 
293 /**
294  *
295  * bdrv_register_buf/bdrv_unregister_buf:
296  *
297  * Register/unregister a buffer for I/O. For example, VFIO drivers are
298  * interested to know the memory areas that would later be used for I/O, so
299  * that they can prepare IOMMU mapping etc., to get better performance.
300  *
301  * Buffers must not overlap and they must be unregistered with the same <host,
302  * size> values that they were registered with.
303  *
304  * Returns: true on success, false on failure
305  */
306 bool bdrv_register_buf(BlockDriverState *bs, void *host, size_t size,
307                        Error **errp);
308 void bdrv_unregister_buf(BlockDriverState *bs, void *host, size_t size);
309 
310 void bdrv_cancel_in_flight(BlockDriverState *bs);
311 
312 #endif /* BLOCK_GLOBAL_STATE_H */
313