xref: /openbmc/qemu/include/block/block.h (revision 24496b8d)
1 #ifndef BLOCK_H
2 #define BLOCK_H
3 
4 #include "block/aio.h"
5 #include "qapi/qapi-types-block-core.h"
6 #include "block/aio-wait.h"
7 #include "qemu/iov.h"
8 #include "qemu/coroutine.h"
9 #include "block/accounting.h"
10 #include "block/dirty-bitmap.h"
11 #include "block/blockjob.h"
12 #include "qemu/hbitmap.h"
13 
14 /* block.c */
15 typedef struct BlockDriver BlockDriver;
16 typedef struct BdrvChild BdrvChild;
17 typedef struct BdrvChildRole BdrvChildRole;
18 
19 typedef struct BlockDriverInfo {
20     /* in bytes, 0 if irrelevant */
21     int cluster_size;
22     /* offset at which the VM state can be saved (0 if not possible) */
23     int64_t vm_state_offset;
24     bool is_dirty;
25     /*
26      * True if unallocated blocks read back as zeroes. This is equivalent
27      * to the LBPRZ flag in the SCSI logical block provisioning page.
28      */
29     bool unallocated_blocks_are_zero;
30     /*
31      * True if this block driver only supports compressed writes
32      */
33     bool needs_compressed_writes;
34 } BlockDriverInfo;
35 
36 typedef struct BlockFragInfo {
37     uint64_t allocated_clusters;
38     uint64_t total_clusters;
39     uint64_t fragmented_clusters;
40     uint64_t compressed_clusters;
41 } BlockFragInfo;
42 
43 typedef enum {
44     BDRV_REQ_COPY_ON_READ       = 0x1,
45     BDRV_REQ_ZERO_WRITE         = 0x2,
46 
47     /*
48      * The BDRV_REQ_MAY_UNMAP flag is used in write_zeroes requests to indicate
49      * that the block driver should unmap (discard) blocks if it is guaranteed
50      * that the result will read back as zeroes. The flag is only passed to the
51      * driver if the block device is opened with BDRV_O_UNMAP.
52      */
53     BDRV_REQ_MAY_UNMAP          = 0x4,
54 
55     /*
56      * The BDRV_REQ_NO_SERIALISING flag is only valid for reads and means that
57      * we don't want wait_serialising_requests() during the read operation.
58      *
59      * This flag is used for backup copy-on-write operations, when we need to
60      * read old data before write (write notifier triggered). It is okay since
61      * we already waited for other serializing requests in the initiating write
62      * (see bdrv_aligned_pwritev), and it is necessary if the initiating write
63      * is already serializing (without the flag, the read would deadlock
64      * waiting for the serialising write to complete).
65      */
66     BDRV_REQ_NO_SERIALISING     = 0x8,
67     BDRV_REQ_FUA                = 0x10,
68     BDRV_REQ_WRITE_COMPRESSED   = 0x20,
69 
70     /* Signifies that this write request will not change the visible disk
71      * content. */
72     BDRV_REQ_WRITE_UNCHANGED    = 0x40,
73 
74     /*
75      * BDRV_REQ_SERIALISING forces request serialisation for writes.
76      * It is used to ensure that writes to the backing file of a backup process
77      * target cannot race with a read of the backup target that defers to the
78      * backing file.
79      *
80      * Note, that BDRV_REQ_SERIALISING is _not_ opposite in meaning to
81      * BDRV_REQ_NO_SERIALISING. A more descriptive name for the latter might be
82      * _DO_NOT_WAIT_FOR_SERIALISING, except that is too long.
83      */
84     BDRV_REQ_SERIALISING        = 0x80,
85 
86     /* Execute the request only if the operation can be offloaded or otherwise
87      * be executed efficiently, but return an error instead of using a slow
88      * fallback. */
89     BDRV_REQ_NO_FALLBACK        = 0x100,
90 
91     /* Mask of valid flags */
92     BDRV_REQ_MASK               = 0x1ff,
93 } BdrvRequestFlags;
94 
95 typedef struct BlockSizes {
96     uint32_t phys;
97     uint32_t log;
98 } BlockSizes;
99 
100 typedef struct HDGeometry {
101     uint32_t heads;
102     uint32_t sectors;
103     uint32_t cylinders;
104 } HDGeometry;
105 
106 #define BDRV_O_RDWR        0x0002
107 #define BDRV_O_RESIZE      0x0004 /* request permission for resizing the node */
108 #define BDRV_O_SNAPSHOT    0x0008 /* open the file read only and save writes in a snapshot */
109 #define BDRV_O_TEMPORARY   0x0010 /* delete the file after use */
110 #define BDRV_O_NOCACHE     0x0020 /* do not use the host page cache */
111 #define BDRV_O_NATIVE_AIO  0x0080 /* use native AIO instead of the thread pool */
112 #define BDRV_O_NO_BACKING  0x0100 /* don't open the backing file */
113 #define BDRV_O_NO_FLUSH    0x0200 /* disable flushing on this disk */
114 #define BDRV_O_COPY_ON_READ 0x0400 /* copy read backing sectors into image */
115 #define BDRV_O_INACTIVE    0x0800  /* consistency hint for migration handoff */
116 #define BDRV_O_CHECK       0x1000  /* open solely for consistency check */
117 #define BDRV_O_ALLOW_RDWR  0x2000  /* allow reopen to change from r/o to r/w */
118 #define BDRV_O_UNMAP       0x4000  /* execute guest UNMAP/TRIM operations */
119 #define BDRV_O_PROTOCOL    0x8000  /* if no block driver is explicitly given:
120                                       select an appropriate protocol driver,
121                                       ignoring the format layer */
122 #define BDRV_O_NO_IO       0x10000 /* don't initialize for I/O */
123 #define BDRV_O_AUTO_RDONLY 0x20000 /* degrade to read-only if opening read-write fails */
124 
125 #define BDRV_O_CACHE_MASK  (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH)
126 
127 
128 /* Option names of options parsed by the block layer */
129 
130 #define BDRV_OPT_CACHE_WB       "cache.writeback"
131 #define BDRV_OPT_CACHE_DIRECT   "cache.direct"
132 #define BDRV_OPT_CACHE_NO_FLUSH "cache.no-flush"
133 #define BDRV_OPT_READ_ONLY      "read-only"
134 #define BDRV_OPT_AUTO_READ_ONLY "auto-read-only"
135 #define BDRV_OPT_DISCARD        "discard"
136 #define BDRV_OPT_FORCE_SHARE    "force-share"
137 
138 
139 #define BDRV_SECTOR_BITS   9
140 #define BDRV_SECTOR_SIZE   (1ULL << BDRV_SECTOR_BITS)
141 #define BDRV_SECTOR_MASK   ~(BDRV_SECTOR_SIZE - 1)
142 
143 #define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \
144                                      INT_MAX >> BDRV_SECTOR_BITS)
145 #define BDRV_REQUEST_MAX_BYTES (BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS)
146 
147 /*
148  * Allocation status flags for bdrv_block_status() and friends.
149  *
150  * Public flags:
151  * BDRV_BLOCK_DATA: allocation for data at offset is tied to this layer
152  * BDRV_BLOCK_ZERO: offset reads as zero
153  * BDRV_BLOCK_OFFSET_VALID: an associated offset exists for accessing raw data
154  * BDRV_BLOCK_ALLOCATED: the content of the block is determined by this
155  *                       layer rather than any backing, set by block layer
156  * BDRV_BLOCK_EOF: the returned pnum covers through end of file for this
157  *                 layer, set by block layer
158  *
159  * Internal flag:
160  * BDRV_BLOCK_RAW: for use by passthrough drivers, such as raw, to request
161  *                 that the block layer recompute the answer from the returned
162  *                 BDS; must be accompanied by just BDRV_BLOCK_OFFSET_VALID.
163  *
164  * If BDRV_BLOCK_OFFSET_VALID is set, the map parameter represents the
165  * host offset within the returned BDS that is allocated for the
166  * corresponding raw guest data.  However, whether that offset
167  * actually contains data also depends on BDRV_BLOCK_DATA, as follows:
168  *
169  * DATA ZERO OFFSET_VALID
170  *  t    t        t       sectors read as zero, returned file is zero at offset
171  *  t    f        t       sectors read as valid from file at offset
172  *  f    t        t       sectors preallocated, read as zero, returned file not
173  *                        necessarily zero at offset
174  *  f    f        t       sectors preallocated but read from backing_hd,
175  *                        returned file contains garbage at offset
176  *  t    t        f       sectors preallocated, read as zero, unknown offset
177  *  t    f        f       sectors read from unknown file or offset
178  *  f    t        f       not allocated or unknown offset, read as zero
179  *  f    f        f       not allocated or unknown offset, read from backing_hd
180  */
181 #define BDRV_BLOCK_DATA         0x01
182 #define BDRV_BLOCK_ZERO         0x02
183 #define BDRV_BLOCK_OFFSET_VALID 0x04
184 #define BDRV_BLOCK_RAW          0x08
185 #define BDRV_BLOCK_ALLOCATED    0x10
186 #define BDRV_BLOCK_EOF          0x20
187 #define BDRV_BLOCK_OFFSET_MASK  BDRV_SECTOR_MASK
188 
189 typedef QSIMPLEQ_HEAD(BlockReopenQueue, BlockReopenQueueEntry) BlockReopenQueue;
190 
191 typedef struct BDRVReopenState {
192     BlockDriverState *bs;
193     int flags;
194     BlockdevDetectZeroesOptions detect_zeroes;
195     bool backing_missing;
196     bool replace_backing_bs;  /* new_backing_bs is ignored if this is false */
197     BlockDriverState *new_backing_bs; /* If NULL then detach the current bs */
198     uint64_t perm, shared_perm;
199     QDict *options;
200     QDict *explicit_options;
201     void *opaque;
202 } BDRVReopenState;
203 
204 /*
205  * Block operation types
206  */
207 typedef enum BlockOpType {
208     BLOCK_OP_TYPE_BACKUP_SOURCE,
209     BLOCK_OP_TYPE_BACKUP_TARGET,
210     BLOCK_OP_TYPE_CHANGE,
211     BLOCK_OP_TYPE_COMMIT_SOURCE,
212     BLOCK_OP_TYPE_COMMIT_TARGET,
213     BLOCK_OP_TYPE_DATAPLANE,
214     BLOCK_OP_TYPE_DRIVE_DEL,
215     BLOCK_OP_TYPE_EJECT,
216     BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
217     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT,
218     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
219     BLOCK_OP_TYPE_MIRROR_SOURCE,
220     BLOCK_OP_TYPE_MIRROR_TARGET,
221     BLOCK_OP_TYPE_RESIZE,
222     BLOCK_OP_TYPE_STREAM,
223     BLOCK_OP_TYPE_REPLACE,
224     BLOCK_OP_TYPE_MAX,
225 } BlockOpType;
226 
227 /* Block node permission constants */
228 enum {
229     /**
230      * A user that has the "permission" of consistent reads is guaranteed that
231      * their view of the contents of the block device is complete and
232      * self-consistent, representing the contents of a disk at a specific
233      * point.
234      *
235      * For most block devices (including their backing files) this is true, but
236      * the property cannot be maintained in a few situations like for
237      * intermediate nodes of a commit block job.
238      */
239     BLK_PERM_CONSISTENT_READ    = 0x01,
240 
241     /** This permission is required to change the visible disk contents. */
242     BLK_PERM_WRITE              = 0x02,
243 
244     /**
245      * This permission (which is weaker than BLK_PERM_WRITE) is both enough and
246      * required for writes to the block node when the caller promises that
247      * the visible disk content doesn't change.
248      *
249      * As the BLK_PERM_WRITE permission is strictly stronger, either is
250      * sufficient to perform an unchanging write.
251      */
252     BLK_PERM_WRITE_UNCHANGED    = 0x04,
253 
254     /** This permission is required to change the size of a block node. */
255     BLK_PERM_RESIZE             = 0x08,
256 
257     /**
258      * This permission is required to change the node that this BdrvChild
259      * points to.
260      */
261     BLK_PERM_GRAPH_MOD          = 0x10,
262 
263     BLK_PERM_ALL                = 0x1f,
264 
265     DEFAULT_PERM_PASSTHROUGH    = BLK_PERM_CONSISTENT_READ
266                                  | BLK_PERM_WRITE
267                                  | BLK_PERM_WRITE_UNCHANGED
268                                  | BLK_PERM_RESIZE,
269 
270     DEFAULT_PERM_UNCHANGED      = BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH,
271 };
272 
273 char *bdrv_perm_names(uint64_t perm);
274 
275 /* disk I/O throttling */
276 void bdrv_init(void);
277 void bdrv_init_with_whitelist(void);
278 bool bdrv_uses_whitelist(void);
279 int bdrv_is_whitelisted(BlockDriver *drv, bool read_only);
280 BlockDriver *bdrv_find_protocol(const char *filename,
281                                 bool allow_protocol_prefix,
282                                 Error **errp);
283 BlockDriver *bdrv_find_format(const char *format_name);
284 int bdrv_create(BlockDriver *drv, const char* filename,
285                 QemuOpts *opts, Error **errp);
286 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp);
287 BlockDriverState *bdrv_new(void);
288 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
289                  Error **errp);
290 void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
291                        Error **errp);
292 
293 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough);
294 int bdrv_parse_discard_flags(const char *mode, int *flags);
295 BdrvChild *bdrv_open_child(const char *filename,
296                            QDict *options, const char *bdref_key,
297                            BlockDriverState* parent,
298                            const BdrvChildRole *child_role,
299                            bool allow_none, Error **errp);
300 BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp);
301 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
302                          Error **errp);
303 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
304                            const char *bdref_key, Error **errp);
305 BlockDriverState *bdrv_open(const char *filename, const char *reference,
306                             QDict *options, int flags, Error **errp);
307 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
308                                        int flags, Error **errp);
309 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
310                                     BlockDriverState *bs, QDict *options,
311                                     bool keep_old_opts);
312 int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp);
313 int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
314                               Error **errp);
315 int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
316                         BlockReopenQueue *queue, Error **errp);
317 void bdrv_reopen_commit(BDRVReopenState *reopen_state);
318 void bdrv_reopen_abort(BDRVReopenState *reopen_state);
319 int bdrv_read(BdrvChild *child, int64_t sector_num,
320               uint8_t *buf, int nb_sectors);
321 int bdrv_write(BdrvChild *child, int64_t sector_num,
322                const uint8_t *buf, int nb_sectors);
323 int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
324                        int bytes, BdrvRequestFlags flags);
325 int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
326 int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes);
327 int bdrv_preadv(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
328 int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes);
329 int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
330 int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
331                      const void *buf, int count);
332 /*
333  * Efficiently zero a region of the disk image.  Note that this is a regular
334  * I/O request like read or write and should have a reasonable size.  This
335  * function is not suitable for zeroing the entire image in a single request
336  * because it may allocate memory for the entire region.
337  */
338 int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
339                                        int bytes, BdrvRequestFlags flags);
340 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
341     const char *backing_file);
342 void bdrv_refresh_filename(BlockDriverState *bs);
343 
344 int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset,
345                                   PreallocMode prealloc, Error **errp);
346 int bdrv_truncate(BdrvChild *child, int64_t offset, PreallocMode prealloc,
347                   Error **errp);
348 
349 int64_t bdrv_nb_sectors(BlockDriverState *bs);
350 int64_t bdrv_getlength(BlockDriverState *bs);
351 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
352 BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
353                                BlockDriverState *in_bs, Error **errp);
354 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
355 void bdrv_refresh_limits(BlockDriverState *bs, Error **errp);
356 int bdrv_commit(BlockDriverState *bs);
357 int bdrv_change_backing_file(BlockDriverState *bs,
358     const char *backing_file, const char *backing_fmt);
359 void bdrv_register(BlockDriver *bdrv);
360 int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
361                            const char *backing_file_str);
362 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
363                                     BlockDriverState *bs);
364 BlockDriverState *bdrv_find_base(BlockDriverState *bs);
365 bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base,
366                                   Error **errp);
367 int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base,
368                               Error **errp);
369 void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base);
370 
371 
372 typedef struct BdrvCheckResult {
373     int corruptions;
374     int leaks;
375     int check_errors;
376     int corruptions_fixed;
377     int leaks_fixed;
378     int64_t image_end_offset;
379     BlockFragInfo bfi;
380 } BdrvCheckResult;
381 
382 typedef enum {
383     BDRV_FIX_LEAKS    = 1,
384     BDRV_FIX_ERRORS   = 2,
385 } BdrvCheckMode;
386 
387 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
388 
389 /* The units of offset and total_work_size may be chosen arbitrarily by the
390  * block driver; total_work_size may change during the course of the amendment
391  * operation */
392 typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
393                                       int64_t total_work_size, void *opaque);
394 int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
395                        BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
396                        Error **errp);
397 
398 /* external snapshots */
399 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
400                                       BlockDriverState *candidate);
401 bool bdrv_is_first_non_filter(BlockDriverState *candidate);
402 
403 /* check if a named node can be replaced when doing drive-mirror */
404 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
405                                         const char *node_name, Error **errp);
406 
407 /* async block I/O */
408 void bdrv_aio_cancel(BlockAIOCB *acb);
409 void bdrv_aio_cancel_async(BlockAIOCB *acb);
410 
411 /* sg packet commands */
412 int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf);
413 
414 /* Invalidate any cached metadata used by image formats */
415 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp);
416 void bdrv_invalidate_cache_all(Error **errp);
417 int bdrv_inactivate_all(void);
418 
419 /* Ensure contents are flushed to disk.  */
420 int bdrv_flush(BlockDriverState *bs);
421 int coroutine_fn bdrv_co_flush(BlockDriverState *bs);
422 int bdrv_flush_all(void);
423 void bdrv_close_all(void);
424 void bdrv_drain(BlockDriverState *bs);
425 void coroutine_fn bdrv_co_drain(BlockDriverState *bs);
426 void bdrv_drain_all_begin(void);
427 void bdrv_drain_all_end(void);
428 void bdrv_drain_all(void);
429 
430 #define BDRV_POLL_WHILE(bs, cond) ({                       \
431     BlockDriverState *bs_ = (bs);                          \
432     AIO_WAIT_WHILE(bdrv_get_aio_context(bs_),              \
433                    cond); })
434 
435 int bdrv_pdiscard(BdrvChild *child, int64_t offset, int bytes);
436 int bdrv_co_pdiscard(BdrvChild *child, int64_t offset, int bytes);
437 int bdrv_has_zero_init_1(BlockDriverState *bs);
438 int bdrv_has_zero_init(BlockDriverState *bs);
439 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs);
440 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
441 int bdrv_block_status(BlockDriverState *bs, int64_t offset,
442                       int64_t bytes, int64_t *pnum, int64_t *map,
443                       BlockDriverState **file);
444 int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
445                             int64_t offset, int64_t bytes, int64_t *pnum,
446                             int64_t *map, BlockDriverState **file);
447 int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
448                       int64_t *pnum);
449 int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
450                             int64_t offset, int64_t bytes, int64_t *pnum);
451 
452 bool bdrv_is_read_only(BlockDriverState *bs);
453 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
454                            bool ignore_allow_rdw, Error **errp);
455 int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg,
456                               Error **errp);
457 bool bdrv_is_writable(BlockDriverState *bs);
458 bool bdrv_is_sg(BlockDriverState *bs);
459 bool bdrv_is_inserted(BlockDriverState *bs);
460 void bdrv_lock_medium(BlockDriverState *bs, bool locked);
461 void bdrv_eject(BlockDriverState *bs, bool eject_flag);
462 const char *bdrv_get_format_name(BlockDriverState *bs);
463 BlockDriverState *bdrv_find_node(const char *node_name);
464 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp);
465 XDbgBlockGraph *bdrv_get_xdbg_block_graph(Error **errp);
466 BlockDriverState *bdrv_lookup_bs(const char *device,
467                                  const char *node_name,
468                                  Error **errp);
469 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
470 BlockDriverState *bdrv_next_node(BlockDriverState *bs);
471 BlockDriverState *bdrv_next_all_states(BlockDriverState *bs);
472 
473 typedef struct BdrvNextIterator {
474     enum {
475         BDRV_NEXT_BACKEND_ROOTS,
476         BDRV_NEXT_MONITOR_OWNED,
477     } phase;
478     BlockBackend *blk;
479     BlockDriverState *bs;
480 } BdrvNextIterator;
481 
482 BlockDriverState *bdrv_first(BdrvNextIterator *it);
483 BlockDriverState *bdrv_next(BdrvNextIterator *it);
484 void bdrv_next_cleanup(BdrvNextIterator *it);
485 
486 BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs);
487 bool bdrv_is_encrypted(BlockDriverState *bs);
488 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
489                          void *opaque, bool read_only);
490 const char *bdrv_get_node_name(const BlockDriverState *bs);
491 const char *bdrv_get_device_name(const BlockDriverState *bs);
492 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
493 int bdrv_get_flags(BlockDriverState *bs);
494 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
495 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs,
496                                           Error **errp);
497 void bdrv_round_to_clusters(BlockDriverState *bs,
498                             int64_t offset, int64_t bytes,
499                             int64_t *cluster_offset,
500                             int64_t *cluster_bytes);
501 
502 void bdrv_get_backing_filename(BlockDriverState *bs,
503                                char *filename, int filename_size);
504 char *bdrv_get_full_backing_filename(BlockDriverState *bs, Error **errp);
505 char *bdrv_get_full_backing_filename_from_filename(const char *backed,
506                                                    const char *backing,
507                                                    Error **errp);
508 char *bdrv_dirname(BlockDriverState *bs, Error **errp);
509 
510 int path_has_protocol(const char *path);
511 int path_is_absolute(const char *path);
512 char *path_combine(const char *base_path, const char *filename);
513 
514 int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
515 int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
516 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
517                       int64_t pos, int size);
518 
519 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
520                       int64_t pos, int size);
521 
522 void bdrv_img_create(const char *filename, const char *fmt,
523                      const char *base_filename, const char *base_fmt,
524                      char *options, uint64_t img_size, int flags,
525                      bool quiet, Error **errp);
526 
527 /* Returns the alignment in bytes that is required so that no bounce buffer
528  * is required throughout the stack */
529 size_t bdrv_min_mem_align(BlockDriverState *bs);
530 /* Returns optimal alignment in bytes for bounce buffer */
531 size_t bdrv_opt_mem_align(BlockDriverState *bs);
532 void *qemu_blockalign(BlockDriverState *bs, size_t size);
533 void *qemu_blockalign0(BlockDriverState *bs, size_t size);
534 void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
535 void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
536 bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);
537 
538 void bdrv_enable_copy_on_read(BlockDriverState *bs);
539 void bdrv_disable_copy_on_read(BlockDriverState *bs);
540 
541 void bdrv_ref(BlockDriverState *bs);
542 void bdrv_unref(BlockDriverState *bs);
543 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child);
544 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
545                              BlockDriverState *child_bs,
546                              const char *child_name,
547                              const BdrvChildRole *child_role,
548                              Error **errp);
549 
550 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
551 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);
552 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason);
553 void bdrv_op_block_all(BlockDriverState *bs, Error *reason);
554 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason);
555 bool bdrv_op_blocker_is_empty(BlockDriverState *bs);
556 
557 #define BLKDBG_EVENT(child, evt) \
558     do { \
559         if (child) { \
560             bdrv_debug_event(child->bs, evt); \
561         } \
562     } while (0)
563 
564 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
565 
566 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
567                            const char *tag);
568 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag);
569 int bdrv_debug_resume(BlockDriverState *bs, const char *tag);
570 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag);
571 
572 /**
573  * bdrv_get_aio_context:
574  *
575  * Returns: the currently bound #AioContext
576  */
577 AioContext *bdrv_get_aio_context(BlockDriverState *bs);
578 
579 /**
580  * Transfer control to @co in the aio context of @bs
581  */
582 void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co);
583 
584 /**
585  * bdrv_set_aio_context:
586  *
587  * Changes the #AioContext used for fd handlers, timers, and BHs by this
588  * BlockDriverState and all its children.
589  *
590  * This function must be called with iothread lock held.
591  */
592 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context);
593 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
594 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
595 
596 void bdrv_io_plug(BlockDriverState *bs);
597 void bdrv_io_unplug(BlockDriverState *bs);
598 
599 /**
600  * bdrv_parent_drained_begin:
601  *
602  * Begin a quiesced section of all users of @bs. This is part of
603  * bdrv_drained_begin.
604  */
605 void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore,
606                                bool ignore_bds_parents);
607 
608 /**
609  * bdrv_parent_drained_begin_single:
610  *
611  * Begin a quiesced section for the parent of @c. If @poll is true, wait for
612  * any pending activity to cease.
613  */
614 void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll);
615 
616 /**
617  * bdrv_parent_drained_end:
618  *
619  * End a quiesced section of all users of @bs. This is part of
620  * bdrv_drained_end.
621  */
622 void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore,
623                              bool ignore_bds_parents);
624 
625 /**
626  * bdrv_drain_poll:
627  *
628  * Poll for pending requests in @bs, its parents (except for @ignore_parent),
629  * and if @recursive is true its children as well (used for subtree drain).
630  *
631  * If @ignore_bds_parents is true, parents that are BlockDriverStates must
632  * ignore the drain request because they will be drained separately (used for
633  * drain_all).
634  *
635  * This is part of bdrv_drained_begin.
636  */
637 bool bdrv_drain_poll(BlockDriverState *bs, bool recursive,
638                      BdrvChild *ignore_parent, bool ignore_bds_parents);
639 
640 /**
641  * bdrv_drained_begin:
642  *
643  * Begin a quiesced section for exclusive access to the BDS, by disabling
644  * external request sources including NBD server and device model. Note that
645  * this doesn't block timers or coroutines from submitting more requests, which
646  * means block_job_pause is still necessary.
647  *
648  * This function can be recursive.
649  */
650 void bdrv_drained_begin(BlockDriverState *bs);
651 
652 /**
653  * bdrv_do_drained_begin_quiesce:
654  *
655  * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already
656  * running requests to complete.
657  */
658 void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,
659                                    BdrvChild *parent, bool ignore_bds_parents);
660 
661 /**
662  * Like bdrv_drained_begin, but recursively begins a quiesced section for
663  * exclusive access to all child nodes as well.
664  */
665 void bdrv_subtree_drained_begin(BlockDriverState *bs);
666 
667 /**
668  * bdrv_drained_end:
669  *
670  * End a quiescent section started by bdrv_drained_begin().
671  */
672 void bdrv_drained_end(BlockDriverState *bs);
673 
674 /**
675  * End a quiescent section started by bdrv_subtree_drained_begin().
676  */
677 void bdrv_subtree_drained_end(BlockDriverState *bs);
678 
679 void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
680                     Error **errp);
681 void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
682 
683 bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
684                                      uint32_t granularity, Error **errp);
685 /**
686  *
687  * bdrv_register_buf/bdrv_unregister_buf:
688  *
689  * Register/unregister a buffer for I/O. For example, VFIO drivers are
690  * interested to know the memory areas that would later be used for I/O, so
691  * that they can prepare IOMMU mapping etc., to get better performance.
692  */
693 void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size);
694 void bdrv_unregister_buf(BlockDriverState *bs, void *host);
695 
696 /**
697  *
698  * bdrv_co_copy_range:
699  *
700  * Do offloaded copy between two children. If the operation is not implemented
701  * by the driver, or if the backend storage doesn't support it, a negative
702  * error code will be returned.
703  *
704  * Note: block layer doesn't emulate or fallback to a bounce buffer approach
705  * because usually the caller shouldn't attempt offloaded copy any more (e.g.
706  * calling copy_file_range(2)) after the first error, thus it should fall back
707  * to a read+write path in the caller level.
708  *
709  * @src: Source child to copy data from
710  * @src_offset: offset in @src image to read data
711  * @dst: Destination child to copy data to
712  * @dst_offset: offset in @dst image to write data
713  * @bytes: number of bytes to copy
714  * @flags: request flags. Supported flags:
715  *         BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero
716  *                               write on @dst as if bdrv_co_pwrite_zeroes is
717  *                               called. Used to simplify caller code, or
718  *                               during BlockDriver.bdrv_co_copy_range_from()
719  *                               recursion.
720  *         BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping
721  *                                   requests currently in flight.
722  *
723  * Returns: 0 if succeeded; negative error code if failed.
724  **/
725 int coroutine_fn bdrv_co_copy_range(BdrvChild *src, uint64_t src_offset,
726                                     BdrvChild *dst, uint64_t dst_offset,
727                                     uint64_t bytes, BdrvRequestFlags read_flags,
728                                     BdrvRequestFlags write_flags);
729 #endif
730