xref: /openbmc/qemu/include/block/block.h (revision 62dd4eda)
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 #define BDRV_OPT_FORCE_SHARE    "force-share"
113 
114 
115 #define BDRV_SECTOR_BITS   9
116 #define BDRV_SECTOR_SIZE   (1ULL << BDRV_SECTOR_BITS)
117 #define BDRV_SECTOR_MASK   ~(BDRV_SECTOR_SIZE - 1)
118 
119 #define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \
120                                      INT_MAX >> BDRV_SECTOR_BITS)
121 #define BDRV_REQUEST_MAX_BYTES (BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS)
122 
123 /*
124  * Allocation status flags for bdrv_get_block_status() and friends.
125  *
126  * Public flags:
127  * BDRV_BLOCK_DATA: allocation for data at offset is tied to this layer
128  * BDRV_BLOCK_ZERO: offset reads as zero
129  * BDRV_BLOCK_OFFSET_VALID: an associated offset exists for accessing raw data
130  * BDRV_BLOCK_ALLOCATED: the content of the block is determined by this
131  *                       layer (short for DATA || ZERO), set by block layer
132  * BDRV_BLOCK_EOF: the returned pnum covers through end of file for this layer
133  *
134  * Internal flag:
135  * BDRV_BLOCK_RAW: for use by passthrough drivers, such as raw, to request
136  *                 that the block layer recompute the answer from the returned
137  *                 BDS; must be accompanied by just BDRV_BLOCK_OFFSET_VALID.
138  *
139  * If BDRV_BLOCK_OFFSET_VALID is set, bits 9-62 (BDRV_BLOCK_OFFSET_MASK)
140  * represent the offset in the returned BDS that is allocated for the
141  * corresponding raw data; however, whether that offset actually contains
142  * data also depends on BDRV_BLOCK_DATA and BDRV_BLOCK_ZERO, as follows:
143  *
144  * DATA ZERO OFFSET_VALID
145  *  t    t        t       sectors read as zero, returned file is zero at offset
146  *  t    f        t       sectors read as valid from file at offset
147  *  f    t        t       sectors preallocated, read as zero, returned file not
148  *                        necessarily zero at offset
149  *  f    f        t       sectors preallocated but read from backing_hd,
150  *                        returned file contains garbage at offset
151  *  t    t        f       sectors preallocated, read as zero, unknown offset
152  *  t    f        f       sectors read from unknown file or offset
153  *  f    t        f       not allocated or unknown offset, read as zero
154  *  f    f        f       not allocated or unknown offset, read from backing_hd
155  */
156 #define BDRV_BLOCK_DATA         0x01
157 #define BDRV_BLOCK_ZERO         0x02
158 #define BDRV_BLOCK_OFFSET_VALID 0x04
159 #define BDRV_BLOCK_RAW          0x08
160 #define BDRV_BLOCK_ALLOCATED    0x10
161 #define BDRV_BLOCK_EOF          0x20
162 #define BDRV_BLOCK_OFFSET_MASK  BDRV_SECTOR_MASK
163 
164 typedef QSIMPLEQ_HEAD(BlockReopenQueue, BlockReopenQueueEntry) BlockReopenQueue;
165 
166 typedef struct BDRVReopenState {
167     BlockDriverState *bs;
168     int flags;
169     uint64_t perm, shared_perm;
170     QDict *options;
171     QDict *explicit_options;
172     void *opaque;
173 } BDRVReopenState;
174 
175 /*
176  * Block operation types
177  */
178 typedef enum BlockOpType {
179     BLOCK_OP_TYPE_BACKUP_SOURCE,
180     BLOCK_OP_TYPE_BACKUP_TARGET,
181     BLOCK_OP_TYPE_CHANGE,
182     BLOCK_OP_TYPE_COMMIT_SOURCE,
183     BLOCK_OP_TYPE_COMMIT_TARGET,
184     BLOCK_OP_TYPE_DATAPLANE,
185     BLOCK_OP_TYPE_DRIVE_DEL,
186     BLOCK_OP_TYPE_EJECT,
187     BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
188     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT,
189     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
190     BLOCK_OP_TYPE_MIRROR_SOURCE,
191     BLOCK_OP_TYPE_MIRROR_TARGET,
192     BLOCK_OP_TYPE_RESIZE,
193     BLOCK_OP_TYPE_STREAM,
194     BLOCK_OP_TYPE_REPLACE,
195     BLOCK_OP_TYPE_MAX,
196 } BlockOpType;
197 
198 /* Block node permission constants */
199 enum {
200     /**
201      * A user that has the "permission" of consistent reads is guaranteed that
202      * their view of the contents of the block device is complete and
203      * self-consistent, representing the contents of a disk at a specific
204      * point.
205      *
206      * For most block devices (including their backing files) this is true, but
207      * the property cannot be maintained in a few situations like for
208      * intermediate nodes of a commit block job.
209      */
210     BLK_PERM_CONSISTENT_READ    = 0x01,
211 
212     /** This permission is required to change the visible disk contents. */
213     BLK_PERM_WRITE              = 0x02,
214 
215     /**
216      * This permission (which is weaker than BLK_PERM_WRITE) is both enough and
217      * required for writes to the block node when the caller promises that
218      * the visible disk content doesn't change.
219      */
220     BLK_PERM_WRITE_UNCHANGED    = 0x04,
221 
222     /** This permission is required to change the size of a block node. */
223     BLK_PERM_RESIZE             = 0x08,
224 
225     /**
226      * This permission is required to change the node that this BdrvChild
227      * points to.
228      */
229     BLK_PERM_GRAPH_MOD          = 0x10,
230 
231     BLK_PERM_ALL                = 0x1f,
232 };
233 
234 char *bdrv_perm_names(uint64_t perm);
235 
236 /* disk I/O throttling */
237 void bdrv_init(void);
238 void bdrv_init_with_whitelist(void);
239 bool bdrv_uses_whitelist(void);
240 BlockDriver *bdrv_find_protocol(const char *filename,
241                                 bool allow_protocol_prefix,
242                                 Error **errp);
243 BlockDriver *bdrv_find_format(const char *format_name);
244 int bdrv_create(BlockDriver *drv, const char* filename,
245                 QemuOpts *opts, Error **errp);
246 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp);
247 BlockDriverState *bdrv_new(void);
248 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
249                  Error **errp);
250 void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
251                        Error **errp);
252 
253 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough);
254 int bdrv_parse_discard_flags(const char *mode, int *flags);
255 BdrvChild *bdrv_open_child(const char *filename,
256                            QDict *options, const char *bdref_key,
257                            BlockDriverState* parent,
258                            const BdrvChildRole *child_role,
259                            bool allow_none, Error **errp);
260 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
261                          Error **errp);
262 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
263                            const char *bdref_key, Error **errp);
264 BlockDriverState *bdrv_open(const char *filename, const char *reference,
265                             QDict *options, int flags, Error **errp);
266 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
267                                        int flags, Error **errp);
268 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
269                                     BlockDriverState *bs,
270                                     QDict *options, int flags);
271 int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **errp);
272 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp);
273 int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
274                         BlockReopenQueue *queue, Error **errp);
275 void bdrv_reopen_commit(BDRVReopenState *reopen_state);
276 void bdrv_reopen_abort(BDRVReopenState *reopen_state);
277 int bdrv_read(BdrvChild *child, int64_t sector_num,
278               uint8_t *buf, int nb_sectors);
279 int bdrv_write(BdrvChild *child, int64_t sector_num,
280                const uint8_t *buf, int nb_sectors);
281 int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
282                        int bytes, BdrvRequestFlags flags);
283 int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
284 int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes);
285 int bdrv_preadv(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
286 int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes);
287 int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
288 int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
289                      const void *buf, int count);
290 int coroutine_fn bdrv_co_readv(BdrvChild *child, int64_t sector_num,
291                                int nb_sectors, QEMUIOVector *qiov);
292 int coroutine_fn bdrv_co_writev(BdrvChild *child, int64_t sector_num,
293                                int nb_sectors, QEMUIOVector *qiov);
294 /*
295  * Efficiently zero a region of the disk image.  Note that this is a regular
296  * I/O request like read or write and should have a reasonable size.  This
297  * function is not suitable for zeroing the entire image in a single request
298  * because it may allocate memory for the entire region.
299  */
300 int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
301                                        int bytes, BdrvRequestFlags flags);
302 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
303     const char *backing_file);
304 void bdrv_refresh_filename(BlockDriverState *bs);
305 int bdrv_truncate(BdrvChild *child, int64_t offset, PreallocMode prealloc,
306                   Error **errp);
307 int64_t bdrv_nb_sectors(BlockDriverState *bs);
308 int64_t bdrv_getlength(BlockDriverState *bs);
309 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
310 BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
311                                BlockDriverState *in_bs, Error **errp);
312 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
313 void bdrv_refresh_limits(BlockDriverState *bs, Error **errp);
314 int bdrv_commit(BlockDriverState *bs);
315 int bdrv_change_backing_file(BlockDriverState *bs,
316     const char *backing_file, const char *backing_fmt);
317 void bdrv_register(BlockDriver *bdrv);
318 int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
319                            BlockDriverState *base,
320                            const char *backing_file_str);
321 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
322                                     BlockDriverState *bs);
323 BlockDriverState *bdrv_find_base(BlockDriverState *bs);
324 
325 
326 typedef struct BdrvCheckResult {
327     int corruptions;
328     int leaks;
329     int check_errors;
330     int corruptions_fixed;
331     int leaks_fixed;
332     int64_t image_end_offset;
333     BlockFragInfo bfi;
334 } BdrvCheckResult;
335 
336 typedef enum {
337     BDRV_FIX_LEAKS    = 1,
338     BDRV_FIX_ERRORS   = 2,
339 } BdrvCheckMode;
340 
341 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
342 
343 /* The units of offset and total_work_size may be chosen arbitrarily by the
344  * block driver; total_work_size may change during the course of the amendment
345  * operation */
346 typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
347                                       int64_t total_work_size, void *opaque);
348 int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
349                        BlockDriverAmendStatusCB *status_cb, void *cb_opaque);
350 
351 /* external snapshots */
352 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
353                                       BlockDriverState *candidate);
354 bool bdrv_is_first_non_filter(BlockDriverState *candidate);
355 
356 /* check if a named node can be replaced when doing drive-mirror */
357 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
358                                         const char *node_name, Error **errp);
359 
360 /* async block I/O */
361 void bdrv_aio_cancel(BlockAIOCB *acb);
362 void bdrv_aio_cancel_async(BlockAIOCB *acb);
363 
364 /* sg packet commands */
365 int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf);
366 
367 /* Invalidate any cached metadata used by image formats */
368 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp);
369 void bdrv_invalidate_cache_all(Error **errp);
370 int bdrv_inactivate_all(void);
371 
372 /* Ensure contents are flushed to disk.  */
373 int bdrv_flush(BlockDriverState *bs);
374 int coroutine_fn bdrv_co_flush(BlockDriverState *bs);
375 int bdrv_flush_all(void);
376 void bdrv_close_all(void);
377 void bdrv_drain(BlockDriverState *bs);
378 void coroutine_fn bdrv_co_drain(BlockDriverState *bs);
379 void bdrv_drain_all_begin(void);
380 void bdrv_drain_all_end(void);
381 void bdrv_drain_all(void);
382 
383 #define BDRV_POLL_WHILE(bs, cond) ({                       \
384     bool waited_ = false;                                  \
385     bool busy_ = true;                                     \
386     BlockDriverState *bs_ = (bs);                          \
387     AioContext *ctx_ = bdrv_get_aio_context(bs_);          \
388     if (aio_context_in_iothread(ctx_)) {                   \
389         while ((cond) || busy_) {                          \
390             busy_ = aio_poll(ctx_, (cond));                \
391             waited_ |= !!(cond) | busy_;                   \
392         }                                                  \
393     } else {                                               \
394         assert(qemu_get_current_aio_context() ==           \
395                qemu_get_aio_context());                    \
396         /* Ask bdrv_dec_in_flight to wake up the main      \
397          * QEMU AioContext.  Extra I/O threads never take  \
398          * other I/O threads' AioContexts (see for example \
399          * block_job_defer_to_main_loop for how to do it). \
400          */                                                \
401         assert(!bs_->wakeup);                              \
402         /* Set bs->wakeup before evaluating cond.  */      \
403         atomic_mb_set(&bs_->wakeup, true);                 \
404         while (busy_) {                                    \
405             if ((cond)) {                                  \
406                 waited_ = busy_ = true;                    \
407                 aio_context_release(ctx_);                 \
408                 aio_poll(qemu_get_aio_context(), true);    \
409                 aio_context_acquire(ctx_);                 \
410             } else {                                       \
411                 busy_ = aio_poll(ctx_, false);             \
412                 waited_ |= busy_;                          \
413             }                                              \
414         }                                                  \
415         atomic_set(&bs_->wakeup, false);                   \
416     }                                                      \
417     waited_; })
418 
419 int bdrv_pdiscard(BlockDriverState *bs, int64_t offset, int bytes);
420 int bdrv_co_pdiscard(BlockDriverState *bs, int64_t offset, int bytes);
421 int bdrv_has_zero_init_1(BlockDriverState *bs);
422 int bdrv_has_zero_init(BlockDriverState *bs);
423 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs);
424 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
425 int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num,
426                               int nb_sectors, int *pnum,
427                               BlockDriverState **file);
428 int64_t bdrv_get_block_status_above(BlockDriverState *bs,
429                                     BlockDriverState *base,
430                                     int64_t sector_num,
431                                     int nb_sectors, int *pnum,
432                                     BlockDriverState **file);
433 int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
434                       int64_t *pnum);
435 int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
436                             int64_t offset, int64_t bytes, int64_t *pnum);
437 
438 bool bdrv_is_read_only(BlockDriverState *bs);
439 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
440                            bool ignore_allow_rdw, Error **errp);
441 int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp);
442 bool bdrv_is_sg(BlockDriverState *bs);
443 bool bdrv_is_inserted(BlockDriverState *bs);
444 void bdrv_lock_medium(BlockDriverState *bs, bool locked);
445 void bdrv_eject(BlockDriverState *bs, bool eject_flag);
446 const char *bdrv_get_format_name(BlockDriverState *bs);
447 BlockDriverState *bdrv_find_node(const char *node_name);
448 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp);
449 BlockDriverState *bdrv_lookup_bs(const char *device,
450                                  const char *node_name,
451                                  Error **errp);
452 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
453 BlockDriverState *bdrv_next_node(BlockDriverState *bs);
454 
455 typedef struct BdrvNextIterator {
456     enum {
457         BDRV_NEXT_BACKEND_ROOTS,
458         BDRV_NEXT_MONITOR_OWNED,
459     } phase;
460     BlockBackend *blk;
461     BlockDriverState *bs;
462 } BdrvNextIterator;
463 
464 BlockDriverState *bdrv_first(BdrvNextIterator *it);
465 BlockDriverState *bdrv_next(BdrvNextIterator *it);
466 
467 BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs);
468 bool bdrv_is_encrypted(BlockDriverState *bs);
469 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
470                          void *opaque);
471 const char *bdrv_get_node_name(const BlockDriverState *bs);
472 const char *bdrv_get_device_name(const BlockDriverState *bs);
473 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
474 int bdrv_get_flags(BlockDriverState *bs);
475 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
476 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs);
477 void bdrv_round_to_clusters(BlockDriverState *bs,
478                             int64_t offset, unsigned int bytes,
479                             int64_t *cluster_offset,
480                             unsigned int *cluster_bytes);
481 
482 const char *bdrv_get_encrypted_filename(BlockDriverState *bs);
483 void bdrv_get_backing_filename(BlockDriverState *bs,
484                                char *filename, int filename_size);
485 void bdrv_get_full_backing_filename(BlockDriverState *bs,
486                                     char *dest, size_t sz, Error **errp);
487 void bdrv_get_full_backing_filename_from_filename(const char *backed,
488                                                   const char *backing,
489                                                   char *dest, size_t sz,
490                                                   Error **errp);
491 
492 int path_has_protocol(const char *path);
493 int path_is_absolute(const char *path);
494 void path_combine(char *dest, int dest_size,
495                   const char *base_path,
496                   const char *filename);
497 
498 int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
499 int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
500 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
501                       int64_t pos, int size);
502 
503 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
504                       int64_t pos, int size);
505 
506 void bdrv_img_create(const char *filename, const char *fmt,
507                      const char *base_filename, const char *base_fmt,
508                      char *options, uint64_t img_size, int flags,
509                      bool quiet, Error **errp);
510 
511 /* Returns the alignment in bytes that is required so that no bounce buffer
512  * is required throughout the stack */
513 size_t bdrv_min_mem_align(BlockDriverState *bs);
514 /* Returns optimal alignment in bytes for bounce buffer */
515 size_t bdrv_opt_mem_align(BlockDriverState *bs);
516 void *qemu_blockalign(BlockDriverState *bs, size_t size);
517 void *qemu_blockalign0(BlockDriverState *bs, size_t size);
518 void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
519 void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
520 bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);
521 
522 void bdrv_enable_copy_on_read(BlockDriverState *bs);
523 void bdrv_disable_copy_on_read(BlockDriverState *bs);
524 
525 void bdrv_ref(BlockDriverState *bs);
526 void bdrv_unref(BlockDriverState *bs);
527 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child);
528 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
529                              BlockDriverState *child_bs,
530                              const char *child_name,
531                              const BdrvChildRole *child_role,
532                              Error **errp);
533 
534 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
535 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);
536 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason);
537 void bdrv_op_block_all(BlockDriverState *bs, Error *reason);
538 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason);
539 bool bdrv_op_blocker_is_empty(BlockDriverState *bs);
540 
541 #define BLKDBG_EVENT(child, evt) \
542     do { \
543         if (child) { \
544             bdrv_debug_event(child->bs, evt); \
545         } \
546     } while (0)
547 
548 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
549 
550 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
551                            const char *tag);
552 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag);
553 int bdrv_debug_resume(BlockDriverState *bs, const char *tag);
554 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag);
555 
556 /**
557  * bdrv_get_aio_context:
558  *
559  * Returns: the currently bound #AioContext
560  */
561 AioContext *bdrv_get_aio_context(BlockDriverState *bs);
562 
563 /**
564  * Transfer control to @co in the aio context of @bs
565  */
566 void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co);
567 
568 /**
569  * bdrv_set_aio_context:
570  *
571  * Changes the #AioContext used for fd handlers, timers, and BHs by this
572  * BlockDriverState and all its children.
573  *
574  * This function must be called with iothread lock held.
575  */
576 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context);
577 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
578 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
579 
580 void bdrv_io_plug(BlockDriverState *bs);
581 void bdrv_io_unplug(BlockDriverState *bs);
582 
583 /**
584  * bdrv_parent_drained_begin:
585  *
586  * Begin a quiesced section of all users of @bs. This is part of
587  * bdrv_drained_begin.
588  */
589 void bdrv_parent_drained_begin(BlockDriverState *bs);
590 
591 /**
592  * bdrv_parent_drained_end:
593  *
594  * End a quiesced section of all users of @bs. This is part of
595  * bdrv_drained_end.
596  */
597 void bdrv_parent_drained_end(BlockDriverState *bs);
598 
599 /**
600  * bdrv_drained_begin:
601  *
602  * Begin a quiesced section for exclusive access to the BDS, by disabling
603  * external request sources including NBD server and device model. Note that
604  * this doesn't block timers or coroutines from submitting more requests, which
605  * means block_job_pause is still necessary.
606  *
607  * This function can be recursive.
608  */
609 void bdrv_drained_begin(BlockDriverState *bs);
610 
611 /**
612  * bdrv_drained_end:
613  *
614  * End a quiescent section started by bdrv_drained_begin().
615  */
616 void bdrv_drained_end(BlockDriverState *bs);
617 
618 void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
619                     Error **errp);
620 void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
621 
622 bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
623                                      uint32_t granularity, Error **errp);
624 
625 #endif
626