xref: /openbmc/qemu/include/block/block.h (revision 3f53bc61)
1 #ifndef BLOCK_H
2 #define BLOCK_H
3 
4 #include "block/aio.h"
5 #include "qemu/iov.h"
6 #include "qemu/option.h"
7 #include "qemu/coroutine.h"
8 #include "block/accounting.h"
9 #include "block/dirty-bitmap.h"
10 #include "block/blockjob.h"
11 #include "qapi/qmp/qobject.h"
12 #include "qapi-types.h"
13 #include "qemu/hbitmap.h"
14 
15 /* block.c */
16 typedef struct BlockDriver BlockDriver;
17 typedef struct BdrvChild BdrvChild;
18 typedef struct BdrvChildRole BdrvChildRole;
19 
20 typedef struct BlockDriverInfo {
21     /* in bytes, 0 if irrelevant */
22     int cluster_size;
23     /* offset at which the VM state can be saved (0 if not possible) */
24     int64_t vm_state_offset;
25     bool is_dirty;
26     /*
27      * True if unallocated blocks read back as zeroes. This is equivalent
28      * to the LBPRZ flag in the SCSI logical block provisioning page.
29      */
30     bool unallocated_blocks_are_zero;
31     /*
32      * True if the driver can optimize writing zeroes by unmapping
33      * sectors. This is equivalent to the BLKDISCARDZEROES ioctl in Linux
34      * with the difference that in qemu a discard is allowed to silently
35      * fail. Therefore we have to use bdrv_pwrite_zeroes with the
36      * BDRV_REQ_MAY_UNMAP flag for an optimized zero write with unmapping.
37      * After this call the driver has to guarantee that the contents read
38      * back as zero. It is additionally required that the block device is
39      * opened with BDRV_O_UNMAP flag for this to work.
40      */
41     bool can_write_zeroes_with_unmap;
42     /*
43      * True if this block driver only supports compressed writes
44      */
45     bool needs_compressed_writes;
46 } BlockDriverInfo;
47 
48 typedef struct BlockFragInfo {
49     uint64_t allocated_clusters;
50     uint64_t total_clusters;
51     uint64_t fragmented_clusters;
52     uint64_t compressed_clusters;
53 } BlockFragInfo;
54 
55 typedef enum {
56     BDRV_REQ_COPY_ON_READ       = 0x1,
57     BDRV_REQ_ZERO_WRITE         = 0x2,
58     /* The BDRV_REQ_MAY_UNMAP flag is used to indicate that the block driver
59      * is allowed to optimize a write zeroes request by unmapping (discarding)
60      * blocks if it is guaranteed that the result will read back as
61      * zeroes. The flag is only passed to the driver if the block device is
62      * opened with BDRV_O_UNMAP.
63      */
64     BDRV_REQ_MAY_UNMAP          = 0x4,
65     BDRV_REQ_NO_SERIALISING     = 0x8,
66     BDRV_REQ_FUA                = 0x10,
67     BDRV_REQ_WRITE_COMPRESSED   = 0x20,
68 
69     /* Mask of valid flags */
70     BDRV_REQ_MASK               = 0x3f,
71 } BdrvRequestFlags;
72 
73 typedef struct BlockSizes {
74     uint32_t phys;
75     uint32_t log;
76 } BlockSizes;
77 
78 typedef struct HDGeometry {
79     uint32_t heads;
80     uint32_t sectors;
81     uint32_t cylinders;
82 } HDGeometry;
83 
84 #define BDRV_O_RDWR        0x0002
85 #define BDRV_O_RESIZE      0x0004 /* request permission for resizing the node */
86 #define BDRV_O_SNAPSHOT    0x0008 /* open the file read only and save writes in a snapshot */
87 #define BDRV_O_TEMPORARY   0x0010 /* delete the file after use */
88 #define BDRV_O_NOCACHE     0x0020 /* do not use the host page cache */
89 #define BDRV_O_NATIVE_AIO  0x0080 /* use native AIO instead of the thread pool */
90 #define BDRV_O_NO_BACKING  0x0100 /* don't open the backing file */
91 #define BDRV_O_NO_FLUSH    0x0200 /* disable flushing on this disk */
92 #define BDRV_O_COPY_ON_READ 0x0400 /* copy read backing sectors into image */
93 #define BDRV_O_INACTIVE    0x0800  /* consistency hint for migration handoff */
94 #define BDRV_O_CHECK       0x1000  /* open solely for consistency check */
95 #define BDRV_O_ALLOW_RDWR  0x2000  /* allow reopen to change from r/o to r/w */
96 #define BDRV_O_UNMAP       0x4000  /* execute guest UNMAP/TRIM operations */
97 #define BDRV_O_PROTOCOL    0x8000  /* if no block driver is explicitly given:
98                                       select an appropriate protocol driver,
99                                       ignoring the format layer */
100 #define BDRV_O_NO_IO       0x10000 /* don't initialize for I/O */
101 
102 #define BDRV_O_CACHE_MASK  (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH)
103 
104 
105 /* Option names of options parsed by the block layer */
106 
107 #define BDRV_OPT_CACHE_WB       "cache.writeback"
108 #define BDRV_OPT_CACHE_DIRECT   "cache.direct"
109 #define BDRV_OPT_CACHE_NO_FLUSH "cache.no-flush"
110 #define BDRV_OPT_READ_ONLY      "read-only"
111 #define BDRV_OPT_DISCARD        "discard"
112 
113 
114 #define BDRV_SECTOR_BITS   9
115 #define BDRV_SECTOR_SIZE   (1ULL << BDRV_SECTOR_BITS)
116 #define BDRV_SECTOR_MASK   ~(BDRV_SECTOR_SIZE - 1)
117 
118 #define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \
119                                      INT_MAX >> BDRV_SECTOR_BITS)
120 #define BDRV_REQUEST_MAX_BYTES (BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS)
121 
122 /*
123  * Allocation status flags
124  * BDRV_BLOCK_DATA: data is read from a file returned by bdrv_get_block_status.
125  * BDRV_BLOCK_ZERO: sectors read as zero
126  * BDRV_BLOCK_OFFSET_VALID: sector stored as raw data in a file returned by
127  *                          bdrv_get_block_status.
128  * BDRV_BLOCK_ALLOCATED: the content of the block is determined by this
129  *                       layer (as opposed to the backing file)
130  * BDRV_BLOCK_RAW: used internally to indicate that the request
131  *                 was answered by the raw driver and that one
132  *                 should look in bs->file directly.
133  *
134  * If BDRV_BLOCK_OFFSET_VALID is set, bits 9-62 represent the offset in
135  * bs->file where sector data can be read from as raw data.
136  *
137  * DATA == 0 && ZERO == 0 means that data is read from backing_hd if present.
138  *
139  * DATA ZERO OFFSET_VALID
140  *  t    t        t       sectors read as zero, bs->file is zero at offset
141  *  t    f        t       sectors read as valid from bs->file at offset
142  *  f    t        t       sectors preallocated, read as zero, bs->file not
143  *                        necessarily zero at offset
144  *  f    f        t       sectors preallocated but read from backing_hd,
145  *                        bs->file contains garbage at offset
146  *  t    t        f       sectors preallocated, read as zero, unknown offset
147  *  t    f        f       sectors read from unknown file or offset
148  *  f    t        f       not allocated or unknown offset, read as zero
149  *  f    f        f       not allocated or unknown offset, read from backing_hd
150  */
151 #define BDRV_BLOCK_DATA         0x01
152 #define BDRV_BLOCK_ZERO         0x02
153 #define BDRV_BLOCK_OFFSET_VALID 0x04
154 #define BDRV_BLOCK_RAW          0x08
155 #define BDRV_BLOCK_ALLOCATED    0x10
156 #define BDRV_BLOCK_OFFSET_MASK  BDRV_SECTOR_MASK
157 
158 typedef QSIMPLEQ_HEAD(BlockReopenQueue, BlockReopenQueueEntry) BlockReopenQueue;
159 
160 typedef struct BDRVReopenState {
161     BlockDriverState *bs;
162     int flags;
163     QDict *options;
164     QDict *explicit_options;
165     void *opaque;
166 } BDRVReopenState;
167 
168 /*
169  * Block operation types
170  */
171 typedef enum BlockOpType {
172     BLOCK_OP_TYPE_BACKUP_SOURCE,
173     BLOCK_OP_TYPE_BACKUP_TARGET,
174     BLOCK_OP_TYPE_CHANGE,
175     BLOCK_OP_TYPE_COMMIT_SOURCE,
176     BLOCK_OP_TYPE_COMMIT_TARGET,
177     BLOCK_OP_TYPE_DATAPLANE,
178     BLOCK_OP_TYPE_DRIVE_DEL,
179     BLOCK_OP_TYPE_EJECT,
180     BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
181     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT,
182     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
183     BLOCK_OP_TYPE_MIRROR_SOURCE,
184     BLOCK_OP_TYPE_MIRROR_TARGET,
185     BLOCK_OP_TYPE_RESIZE,
186     BLOCK_OP_TYPE_STREAM,
187     BLOCK_OP_TYPE_REPLACE,
188     BLOCK_OP_TYPE_MAX,
189 } BlockOpType;
190 
191 /* Block node permission constants */
192 enum {
193     /**
194      * A user that has the "permission" of consistent reads is guaranteed that
195      * their view of the contents of the block device is complete and
196      * self-consistent, representing the contents of a disk at a specific
197      * point.
198      *
199      * For most block devices (including their backing files) this is true, but
200      * the property cannot be maintained in a few situations like for
201      * intermediate nodes of a commit block job.
202      */
203     BLK_PERM_CONSISTENT_READ    = 0x01,
204 
205     /** This permission is required to change the visible disk contents. */
206     BLK_PERM_WRITE              = 0x02,
207 
208     /**
209      * This permission (which is weaker than BLK_PERM_WRITE) is both enough and
210      * required for writes to the block node when the caller promises that
211      * the visible disk content doesn't change.
212      */
213     BLK_PERM_WRITE_UNCHANGED    = 0x04,
214 
215     /** This permission is required to change the size of a block node. */
216     BLK_PERM_RESIZE             = 0x08,
217 
218     /**
219      * This permission is required to change the node that this BdrvChild
220      * points to.
221      */
222     BLK_PERM_GRAPH_MOD          = 0x10,
223 
224     BLK_PERM_ALL                = 0x1f,
225 };
226 
227 /* disk I/O throttling */
228 void bdrv_init(void);
229 void bdrv_init_with_whitelist(void);
230 bool bdrv_uses_whitelist(void);
231 BlockDriver *bdrv_find_protocol(const char *filename,
232                                 bool allow_protocol_prefix,
233                                 Error **errp);
234 BlockDriver *bdrv_find_format(const char *format_name);
235 int bdrv_create(BlockDriver *drv, const char* filename,
236                 QemuOpts *opts, Error **errp);
237 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp);
238 BlockDriverState *bdrv_new(void);
239 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
240                  Error **errp);
241 void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
242                        Error **errp);
243 
244 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough);
245 int bdrv_parse_discard_flags(const char *mode, int *flags);
246 BdrvChild *bdrv_open_child(const char *filename,
247                            QDict *options, const char *bdref_key,
248                            BlockDriverState* parent,
249                            const BdrvChildRole *child_role,
250                            bool allow_none, Error **errp);
251 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
252                          Error **errp);
253 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
254                            const char *bdref_key, Error **errp);
255 BlockDriverState *bdrv_open(const char *filename, const char *reference,
256                             QDict *options, int flags, Error **errp);
257 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
258                                        int flags, Error **errp);
259 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
260                                     BlockDriverState *bs,
261                                     QDict *options, int flags);
262 int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **errp);
263 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp);
264 int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
265                         BlockReopenQueue *queue, Error **errp);
266 void bdrv_reopen_commit(BDRVReopenState *reopen_state);
267 void bdrv_reopen_abort(BDRVReopenState *reopen_state);
268 int bdrv_read(BdrvChild *child, int64_t sector_num,
269               uint8_t *buf, int nb_sectors);
270 int bdrv_write(BdrvChild *child, int64_t sector_num,
271                const uint8_t *buf, int nb_sectors);
272 int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
273                        int count, BdrvRequestFlags flags);
274 int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
275 int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes);
276 int bdrv_preadv(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
277 int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes);
278 int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
279 int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
280                      const void *buf, int count);
281 int coroutine_fn bdrv_co_readv(BdrvChild *child, int64_t sector_num,
282                                int nb_sectors, QEMUIOVector *qiov);
283 int coroutine_fn bdrv_co_writev(BdrvChild *child, int64_t sector_num,
284                                int nb_sectors, QEMUIOVector *qiov);
285 /*
286  * Efficiently zero a region of the disk image.  Note that this is a regular
287  * I/O request like read or write and should have a reasonable size.  This
288  * function is not suitable for zeroing the entire image in a single request
289  * because it may allocate memory for the entire region.
290  */
291 int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
292                                        int count, BdrvRequestFlags flags);
293 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
294     const char *backing_file);
295 int bdrv_get_backing_file_depth(BlockDriverState *bs);
296 void bdrv_refresh_filename(BlockDriverState *bs);
297 int bdrv_truncate(BdrvChild *child, int64_t offset);
298 int64_t bdrv_nb_sectors(BlockDriverState *bs);
299 int64_t bdrv_getlength(BlockDriverState *bs);
300 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
301 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
302 void bdrv_refresh_limits(BlockDriverState *bs, Error **errp);
303 int bdrv_commit(BlockDriverState *bs);
304 int bdrv_change_backing_file(BlockDriverState *bs,
305     const char *backing_file, const char *backing_fmt);
306 void bdrv_register(BlockDriver *bdrv);
307 int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
308                            BlockDriverState *base,
309                            const char *backing_file_str);
310 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
311                                     BlockDriverState *bs);
312 BlockDriverState *bdrv_find_base(BlockDriverState *bs);
313 
314 
315 typedef struct BdrvCheckResult {
316     int corruptions;
317     int leaks;
318     int check_errors;
319     int corruptions_fixed;
320     int leaks_fixed;
321     int64_t image_end_offset;
322     BlockFragInfo bfi;
323 } BdrvCheckResult;
324 
325 typedef enum {
326     BDRV_FIX_LEAKS    = 1,
327     BDRV_FIX_ERRORS   = 2,
328 } BdrvCheckMode;
329 
330 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
331 
332 /* The units of offset and total_work_size may be chosen arbitrarily by the
333  * block driver; total_work_size may change during the course of the amendment
334  * operation */
335 typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
336                                       int64_t total_work_size, void *opaque);
337 int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
338                        BlockDriverAmendStatusCB *status_cb, void *cb_opaque);
339 
340 /* external snapshots */
341 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
342                                       BlockDriverState *candidate);
343 bool bdrv_is_first_non_filter(BlockDriverState *candidate);
344 
345 /* check if a named node can be replaced when doing drive-mirror */
346 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
347                                         const char *node_name, Error **errp);
348 
349 /* async block I/O */
350 BlockAIOCB *bdrv_aio_readv(BdrvChild *child, int64_t sector_num,
351                            QEMUIOVector *iov, int nb_sectors,
352                            BlockCompletionFunc *cb, void *opaque);
353 BlockAIOCB *bdrv_aio_writev(BdrvChild *child, int64_t sector_num,
354                             QEMUIOVector *iov, int nb_sectors,
355                             BlockCompletionFunc *cb, void *opaque);
356 BlockAIOCB *bdrv_aio_flush(BlockDriverState *bs,
357                            BlockCompletionFunc *cb, void *opaque);
358 void bdrv_aio_cancel(BlockAIOCB *acb);
359 void bdrv_aio_cancel_async(BlockAIOCB *acb);
360 
361 /* sg packet commands */
362 int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf);
363 
364 /* Invalidate any cached metadata used by image formats */
365 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp);
366 void bdrv_invalidate_cache_all(Error **errp);
367 int bdrv_inactivate_all(void);
368 
369 /* Ensure contents are flushed to disk.  */
370 int bdrv_flush(BlockDriverState *bs);
371 int coroutine_fn bdrv_co_flush(BlockDriverState *bs);
372 int bdrv_flush_all(void);
373 void bdrv_close_all(void);
374 void bdrv_drain(BlockDriverState *bs);
375 void coroutine_fn bdrv_co_drain(BlockDriverState *bs);
376 void bdrv_drain_all_begin(void);
377 void bdrv_drain_all_end(void);
378 void bdrv_drain_all(void);
379 
380 #define BDRV_POLL_WHILE(bs, cond) ({                       \
381     bool waited_ = false;                                  \
382     BlockDriverState *bs_ = (bs);                          \
383     AioContext *ctx_ = bdrv_get_aio_context(bs_);          \
384     if (aio_context_in_iothread(ctx_)) {                   \
385         while ((cond)) {                                   \
386             aio_poll(ctx_, true);                          \
387             waited_ = true;                                \
388         }                                                  \
389     } else {                                               \
390         assert(qemu_get_current_aio_context() ==           \
391                qemu_get_aio_context());                    \
392         /* Ask bdrv_dec_in_flight to wake up the main      \
393          * QEMU AioContext.  Extra I/O threads never take  \
394          * other I/O threads' AioContexts (see for example \
395          * block_job_defer_to_main_loop for how to do it). \
396          */                                                \
397         assert(!bs_->wakeup);                              \
398         bs_->wakeup = true;                                \
399         while ((cond)) {                                   \
400             aio_context_release(ctx_);                     \
401             aio_poll(qemu_get_aio_context(), true);        \
402             aio_context_acquire(ctx_);                     \
403             waited_ = true;                                \
404         }                                                  \
405         bs_->wakeup = false;                               \
406     }                                                      \
407     waited_; })
408 
409 int bdrv_pdiscard(BlockDriverState *bs, int64_t offset, int count);
410 int bdrv_co_pdiscard(BlockDriverState *bs, int64_t offset, int count);
411 int bdrv_has_zero_init_1(BlockDriverState *bs);
412 int bdrv_has_zero_init(BlockDriverState *bs);
413 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs);
414 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
415 int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num,
416                               int nb_sectors, int *pnum,
417                               BlockDriverState **file);
418 int64_t bdrv_get_block_status_above(BlockDriverState *bs,
419                                     BlockDriverState *base,
420                                     int64_t sector_num,
421                                     int nb_sectors, int *pnum,
422                                     BlockDriverState **file);
423 int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
424                       int *pnum);
425 int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
426                             int64_t sector_num, int nb_sectors, int *pnum);
427 
428 bool bdrv_is_read_only(BlockDriverState *bs);
429 bool bdrv_is_sg(BlockDriverState *bs);
430 bool bdrv_is_inserted(BlockDriverState *bs);
431 int bdrv_media_changed(BlockDriverState *bs);
432 void bdrv_lock_medium(BlockDriverState *bs, bool locked);
433 void bdrv_eject(BlockDriverState *bs, bool eject_flag);
434 const char *bdrv_get_format_name(BlockDriverState *bs);
435 BlockDriverState *bdrv_find_node(const char *node_name);
436 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp);
437 BlockDriverState *bdrv_lookup_bs(const char *device,
438                                  const char *node_name,
439                                  Error **errp);
440 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
441 BlockDriverState *bdrv_next_node(BlockDriverState *bs);
442 
443 typedef struct BdrvNextIterator {
444     enum {
445         BDRV_NEXT_BACKEND_ROOTS,
446         BDRV_NEXT_MONITOR_OWNED,
447     } phase;
448     BlockBackend *blk;
449     BlockDriverState *bs;
450 } BdrvNextIterator;
451 
452 BlockDriverState *bdrv_first(BdrvNextIterator *it);
453 BlockDriverState *bdrv_next(BdrvNextIterator *it);
454 
455 BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs);
456 bool bdrv_is_encrypted(BlockDriverState *bs);
457 bool bdrv_key_required(BlockDriverState *bs);
458 int bdrv_set_key(BlockDriverState *bs, const char *key);
459 void bdrv_add_key(BlockDriverState *bs, const char *key, Error **errp);
460 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
461                          void *opaque);
462 const char *bdrv_get_node_name(const BlockDriverState *bs);
463 const char *bdrv_get_device_name(const BlockDriverState *bs);
464 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
465 int bdrv_get_flags(BlockDriverState *bs);
466 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
467 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs);
468 void bdrv_round_sectors_to_clusters(BlockDriverState *bs,
469                                     int64_t sector_num, int nb_sectors,
470                                     int64_t *cluster_sector_num,
471                                     int *cluster_nb_sectors);
472 void bdrv_round_to_clusters(BlockDriverState *bs,
473                             int64_t offset, unsigned int bytes,
474                             int64_t *cluster_offset,
475                             unsigned int *cluster_bytes);
476 
477 const char *bdrv_get_encrypted_filename(BlockDriverState *bs);
478 void bdrv_get_backing_filename(BlockDriverState *bs,
479                                char *filename, int filename_size);
480 void bdrv_get_full_backing_filename(BlockDriverState *bs,
481                                     char *dest, size_t sz, Error **errp);
482 void bdrv_get_full_backing_filename_from_filename(const char *backed,
483                                                   const char *backing,
484                                                   char *dest, size_t sz,
485                                                   Error **errp);
486 
487 int path_has_protocol(const char *path);
488 int path_is_absolute(const char *path);
489 void path_combine(char *dest, int dest_size,
490                   const char *base_path,
491                   const char *filename);
492 
493 int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
494 int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
495 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
496                       int64_t pos, int size);
497 
498 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
499                       int64_t pos, int size);
500 
501 void bdrv_img_create(const char *filename, const char *fmt,
502                      const char *base_filename, const char *base_fmt,
503                      char *options, uint64_t img_size, int flags,
504                      Error **errp, bool quiet);
505 
506 /* Returns the alignment in bytes that is required so that no bounce buffer
507  * is required throughout the stack */
508 size_t bdrv_min_mem_align(BlockDriverState *bs);
509 /* Returns optimal alignment in bytes for bounce buffer */
510 size_t bdrv_opt_mem_align(BlockDriverState *bs);
511 void *qemu_blockalign(BlockDriverState *bs, size_t size);
512 void *qemu_blockalign0(BlockDriverState *bs, size_t size);
513 void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
514 void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
515 bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);
516 
517 void bdrv_enable_copy_on_read(BlockDriverState *bs);
518 void bdrv_disable_copy_on_read(BlockDriverState *bs);
519 
520 void bdrv_ref(BlockDriverState *bs);
521 void bdrv_unref(BlockDriverState *bs);
522 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child);
523 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
524                              BlockDriverState *child_bs,
525                              const char *child_name,
526                              const BdrvChildRole *child_role,
527                              Error **errp);
528 
529 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
530 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);
531 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason);
532 void bdrv_op_block_all(BlockDriverState *bs, Error *reason);
533 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason);
534 bool bdrv_op_blocker_is_empty(BlockDriverState *bs);
535 
536 #define BLKDBG_EVENT(child, evt) \
537     do { \
538         if (child) { \
539             bdrv_debug_event(child->bs, evt); \
540         } \
541     } while (0)
542 
543 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
544 
545 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
546                            const char *tag);
547 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag);
548 int bdrv_debug_resume(BlockDriverState *bs, const char *tag);
549 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag);
550 
551 /**
552  * bdrv_get_aio_context:
553  *
554  * Returns: the currently bound #AioContext
555  */
556 AioContext *bdrv_get_aio_context(BlockDriverState *bs);
557 
558 /**
559  * bdrv_set_aio_context:
560  *
561  * Changes the #AioContext used for fd handlers, timers, and BHs by this
562  * BlockDriverState and all its children.
563  *
564  * This function must be called with iothread lock held.
565  */
566 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context);
567 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
568 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
569 
570 void bdrv_io_plug(BlockDriverState *bs);
571 void bdrv_io_unplug(BlockDriverState *bs);
572 
573 /**
574  * bdrv_drained_begin:
575  *
576  * Begin a quiesced section for exclusive access to the BDS, by disabling
577  * external request sources including NBD server and device model. Note that
578  * this doesn't block timers or coroutines from submitting more requests, which
579  * means block_job_pause is still necessary.
580  *
581  * This function can be recursive.
582  */
583 void bdrv_drained_begin(BlockDriverState *bs);
584 
585 /**
586  * bdrv_drained_end:
587  *
588  * End a quiescent section started by bdrv_drained_begin().
589  */
590 void bdrv_drained_end(BlockDriverState *bs);
591 
592 void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
593                     Error **errp);
594 void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
595 
596 #endif
597