xref: /openbmc/qemu/include/block/block.h (revision 06a47ef5)
1 #ifndef BLOCK_H
2 #define BLOCK_H
3 
4 #include "block/aio.h"
5 #include "block/aio-wait.h"
6 #include "qemu/iov.h"
7 #include "qemu/coroutine.h"
8 #include "block/accounting.h"
9 #include "block/dirty-bitmap.h"
10 #include "block/blockjob.h"
11 #include "qemu/hbitmap.h"
12 
13 /* block.c */
14 typedef struct BlockDriver BlockDriver;
15 typedef struct BdrvChild BdrvChild;
16 typedef struct BdrvChildRole BdrvChildRole;
17 
18 typedef struct BlockDriverInfo {
19     /* in bytes, 0 if irrelevant */
20     int cluster_size;
21     /* offset at which the VM state can be saved (0 if not possible) */
22     int64_t vm_state_offset;
23     bool is_dirty;
24     /*
25      * True if unallocated blocks read back as zeroes. This is equivalent
26      * to the LBPRZ flag in the SCSI logical block provisioning page.
27      */
28     bool unallocated_blocks_are_zero;
29     /*
30      * True if this block driver only supports compressed writes
31      */
32     bool needs_compressed_writes;
33 } BlockDriverInfo;
34 
35 typedef struct BlockFragInfo {
36     uint64_t allocated_clusters;
37     uint64_t total_clusters;
38     uint64_t fragmented_clusters;
39     uint64_t compressed_clusters;
40 } BlockFragInfo;
41 
42 typedef enum {
43     BDRV_REQ_COPY_ON_READ       = 0x1,
44     BDRV_REQ_ZERO_WRITE         = 0x2,
45 
46     /*
47      * The BDRV_REQ_MAY_UNMAP flag is used in write_zeroes requests to indicate
48      * that the block driver should unmap (discard) blocks if it is guaranteed
49      * that the result will read back as zeroes. The flag is only passed to the
50      * driver if the block device is opened with BDRV_O_UNMAP.
51      */
52     BDRV_REQ_MAY_UNMAP          = 0x4,
53 
54     BDRV_REQ_FUA                = 0x10,
55     BDRV_REQ_WRITE_COMPRESSED   = 0x20,
56 
57     /* Signifies that this write request will not change the visible disk
58      * content. */
59     BDRV_REQ_WRITE_UNCHANGED    = 0x40,
60 
61     /*
62      * BDRV_REQ_SERIALISING forces request serialisation for writes.
63      * It is used to ensure that writes to the backing file of a backup process
64      * target cannot race with a read of the backup target that defers to the
65      * backing file.
66      *
67      * Note, that BDRV_REQ_SERIALISING is _not_ opposite in meaning to
68      * BDRV_REQ_NO_SERIALISING. A more descriptive name for the latter might be
69      * _DO_NOT_WAIT_FOR_SERIALISING, except that is too long.
70      */
71     BDRV_REQ_SERIALISING        = 0x80,
72 
73     /* Execute the request only if the operation can be offloaded or otherwise
74      * be executed efficiently, but return an error instead of using a slow
75      * fallback. */
76     BDRV_REQ_NO_FALLBACK        = 0x100,
77 
78     /*
79      * BDRV_REQ_PREFETCH may be used only together with BDRV_REQ_COPY_ON_READ
80      * on read request and means that caller doesn't really need data to be
81      * written to qiov parameter which may be NULL.
82      */
83     BDRV_REQ_PREFETCH  = 0x200,
84     /* Mask of valid flags */
85     BDRV_REQ_MASK               = 0x3ff,
86 } BdrvRequestFlags;
87 
88 typedef struct BlockSizes {
89     uint32_t phys;
90     uint32_t log;
91 } BlockSizes;
92 
93 typedef struct HDGeometry {
94     uint32_t heads;
95     uint32_t sectors;
96     uint32_t cylinders;
97 } HDGeometry;
98 
99 #define BDRV_O_RDWR        0x0002
100 #define BDRV_O_RESIZE      0x0004 /* request permission for resizing the node */
101 #define BDRV_O_SNAPSHOT    0x0008 /* open the file read only and save writes in a snapshot */
102 #define BDRV_O_TEMPORARY   0x0010 /* delete the file after use */
103 #define BDRV_O_NOCACHE     0x0020 /* do not use the host page cache */
104 #define BDRV_O_NATIVE_AIO  0x0080 /* use native AIO instead of the thread pool */
105 #define BDRV_O_NO_BACKING  0x0100 /* don't open the backing file */
106 #define BDRV_O_NO_FLUSH    0x0200 /* disable flushing on this disk */
107 #define BDRV_O_COPY_ON_READ 0x0400 /* copy read backing sectors into image */
108 #define BDRV_O_INACTIVE    0x0800  /* consistency hint for migration handoff */
109 #define BDRV_O_CHECK       0x1000  /* open solely for consistency check */
110 #define BDRV_O_ALLOW_RDWR  0x2000  /* allow reopen to change from r/o to r/w */
111 #define BDRV_O_UNMAP       0x4000  /* execute guest UNMAP/TRIM operations */
112 #define BDRV_O_PROTOCOL    0x8000  /* if no block driver is explicitly given:
113                                       select an appropriate protocol driver,
114                                       ignoring the format layer */
115 #define BDRV_O_NO_IO       0x10000 /* don't initialize for I/O */
116 #define BDRV_O_AUTO_RDONLY 0x20000 /* degrade to read-only if opening read-write fails */
117 #define BDRV_O_IO_URING    0x40000 /* use io_uring instead of the thread pool */
118 
119 #define BDRV_O_CACHE_MASK  (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH)
120 
121 
122 /* Option names of options parsed by the block layer */
123 
124 #define BDRV_OPT_CACHE_WB       "cache.writeback"
125 #define BDRV_OPT_CACHE_DIRECT   "cache.direct"
126 #define BDRV_OPT_CACHE_NO_FLUSH "cache.no-flush"
127 #define BDRV_OPT_READ_ONLY      "read-only"
128 #define BDRV_OPT_AUTO_READ_ONLY "auto-read-only"
129 #define BDRV_OPT_DISCARD        "discard"
130 #define BDRV_OPT_FORCE_SHARE    "force-share"
131 
132 
133 #define BDRV_SECTOR_BITS   9
134 #define BDRV_SECTOR_SIZE   (1ULL << BDRV_SECTOR_BITS)
135 
136 #define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \
137                                      INT_MAX >> BDRV_SECTOR_BITS)
138 #define BDRV_REQUEST_MAX_BYTES (BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS)
139 
140 /*
141  * Allocation status flags for bdrv_block_status() and friends.
142  *
143  * Public flags:
144  * BDRV_BLOCK_DATA: allocation for data at offset is tied to this layer
145  * BDRV_BLOCK_ZERO: offset reads as zero
146  * BDRV_BLOCK_OFFSET_VALID: an associated offset exists for accessing raw data
147  * BDRV_BLOCK_ALLOCATED: the content of the block is determined by this
148  *                       layer rather than any backing, set by block layer
149  * BDRV_BLOCK_EOF: the returned pnum covers through end of file for this
150  *                 layer, set by block layer
151  *
152  * Internal flags:
153  * BDRV_BLOCK_RAW: for use by passthrough drivers, such as raw, to request
154  *                 that the block layer recompute the answer from the returned
155  *                 BDS; must be accompanied by just BDRV_BLOCK_OFFSET_VALID.
156  * BDRV_BLOCK_RECURSE: request that the block layer will recursively search for
157  *                     zeroes in file child of current block node inside
158  *                     returned region. Only valid together with both
159  *                     BDRV_BLOCK_DATA and BDRV_BLOCK_OFFSET_VALID. Should not
160  *                     appear with BDRV_BLOCK_ZERO.
161  *
162  * If BDRV_BLOCK_OFFSET_VALID is set, the map parameter represents the
163  * host offset within the returned BDS that is allocated for the
164  * corresponding raw guest data.  However, whether that offset
165  * actually contains data also depends on BDRV_BLOCK_DATA, as follows:
166  *
167  * DATA ZERO OFFSET_VALID
168  *  t    t        t       sectors read as zero, returned file is zero at offset
169  *  t    f        t       sectors read as valid from file at offset
170  *  f    t        t       sectors preallocated, read as zero, returned file not
171  *                        necessarily zero at offset
172  *  f    f        t       sectors preallocated but read from backing_hd,
173  *                        returned file contains garbage at offset
174  *  t    t        f       sectors preallocated, read as zero, unknown offset
175  *  t    f        f       sectors read from unknown file or offset
176  *  f    t        f       not allocated or unknown offset, read as zero
177  *  f    f        f       not allocated or unknown offset, read from backing_hd
178  */
179 #define BDRV_BLOCK_DATA         0x01
180 #define BDRV_BLOCK_ZERO         0x02
181 #define BDRV_BLOCK_OFFSET_VALID 0x04
182 #define BDRV_BLOCK_RAW          0x08
183 #define BDRV_BLOCK_ALLOCATED    0x10
184 #define BDRV_BLOCK_EOF          0x20
185 #define BDRV_BLOCK_RECURSE      0x40
186 
187 typedef QTAILQ_HEAD(BlockReopenQueue, BlockReopenQueueEntry) BlockReopenQueue;
188 
189 typedef struct BDRVReopenState {
190     BlockDriverState *bs;
191     int flags;
192     BlockdevDetectZeroesOptions detect_zeroes;
193     bool backing_missing;
194     bool replace_backing_bs;  /* new_backing_bs is ignored if this is false */
195     BlockDriverState *new_backing_bs; /* If NULL then detach the current bs */
196     uint64_t perm, shared_perm;
197     QDict *options;
198     QDict *explicit_options;
199     void *opaque;
200 } BDRVReopenState;
201 
202 /*
203  * Block operation types
204  */
205 typedef enum BlockOpType {
206     BLOCK_OP_TYPE_BACKUP_SOURCE,
207     BLOCK_OP_TYPE_BACKUP_TARGET,
208     BLOCK_OP_TYPE_CHANGE,
209     BLOCK_OP_TYPE_COMMIT_SOURCE,
210     BLOCK_OP_TYPE_COMMIT_TARGET,
211     BLOCK_OP_TYPE_DATAPLANE,
212     BLOCK_OP_TYPE_DRIVE_DEL,
213     BLOCK_OP_TYPE_EJECT,
214     BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
215     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT,
216     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
217     BLOCK_OP_TYPE_MIRROR_SOURCE,
218     BLOCK_OP_TYPE_MIRROR_TARGET,
219     BLOCK_OP_TYPE_RESIZE,
220     BLOCK_OP_TYPE_STREAM,
221     BLOCK_OP_TYPE_REPLACE,
222     BLOCK_OP_TYPE_MAX,
223 } BlockOpType;
224 
225 /* Block node permission constants */
226 enum {
227     /**
228      * A user that has the "permission" of consistent reads is guaranteed that
229      * their view of the contents of the block device is complete and
230      * self-consistent, representing the contents of a disk at a specific
231      * point.
232      *
233      * For most block devices (including their backing files) this is true, but
234      * the property cannot be maintained in a few situations like for
235      * intermediate nodes of a commit block job.
236      */
237     BLK_PERM_CONSISTENT_READ    = 0x01,
238 
239     /** This permission is required to change the visible disk contents. */
240     BLK_PERM_WRITE              = 0x02,
241 
242     /**
243      * This permission (which is weaker than BLK_PERM_WRITE) is both enough and
244      * required for writes to the block node when the caller promises that
245      * the visible disk content doesn't change.
246      *
247      * As the BLK_PERM_WRITE permission is strictly stronger, either is
248      * sufficient to perform an unchanging write.
249      */
250     BLK_PERM_WRITE_UNCHANGED    = 0x04,
251 
252     /** This permission is required to change the size of a block node. */
253     BLK_PERM_RESIZE             = 0x08,
254 
255     /**
256      * This permission is required to change the node that this BdrvChild
257      * points to.
258      */
259     BLK_PERM_GRAPH_MOD          = 0x10,
260 
261     BLK_PERM_ALL                = 0x1f,
262 
263     DEFAULT_PERM_PASSTHROUGH    = BLK_PERM_CONSISTENT_READ
264                                  | BLK_PERM_WRITE
265                                  | BLK_PERM_WRITE_UNCHANGED
266                                  | BLK_PERM_RESIZE,
267 
268     DEFAULT_PERM_UNCHANGED      = BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH,
269 };
270 
271 char *bdrv_perm_names(uint64_t perm);
272 uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm);
273 
274 /* disk I/O throttling */
275 void bdrv_init(void);
276 void bdrv_init_with_whitelist(void);
277 bool bdrv_uses_whitelist(void);
278 int bdrv_is_whitelisted(BlockDriver *drv, bool read_only);
279 BlockDriver *bdrv_find_protocol(const char *filename,
280                                 bool allow_protocol_prefix,
281                                 Error **errp);
282 BlockDriver *bdrv_find_format(const char *format_name);
283 int bdrv_create(BlockDriver *drv, const char* filename,
284                 QemuOpts *opts, Error **errp);
285 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp);
286 BlockDriverState *bdrv_new(void);
287 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
288                  Error **errp);
289 void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
290                        Error **errp);
291 
292 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough);
293 int bdrv_parse_discard_flags(const char *mode, int *flags);
294 BdrvChild *bdrv_open_child(const char *filename,
295                            QDict *options, const char *bdref_key,
296                            BlockDriverState* parent,
297                            const BdrvChildRole *child_role,
298                            bool allow_none, Error **errp);
299 BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp);
300 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
301                          Error **errp);
302 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
303                            const char *bdref_key, Error **errp);
304 BlockDriverState *bdrv_open(const char *filename, const char *reference,
305                             QDict *options, int flags, Error **errp);
306 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
307                                        int flags, Error **errp);
308 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
309                                     BlockDriverState *bs, QDict *options,
310                                     bool keep_old_opts);
311 int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp);
312 int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
313                               Error **errp);
314 int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
315                         BlockReopenQueue *queue, Error **errp);
316 void bdrv_reopen_commit(BDRVReopenState *reopen_state);
317 void bdrv_reopen_abort(BDRVReopenState *reopen_state);
318 int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
319                        int bytes, BdrvRequestFlags flags);
320 int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
321 int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes);
322 int bdrv_preadv(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
323 int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes);
324 int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
325 int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
326                      const void *buf, int count);
327 /*
328  * Efficiently zero a region of the disk image.  Note that this is a regular
329  * I/O request like read or write and should have a reasonable size.  This
330  * function is not suitable for zeroing the entire image in a single request
331  * because it may allocate memory for the entire region.
332  */
333 int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
334                                        int bytes, BdrvRequestFlags flags);
335 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
336     const char *backing_file);
337 void bdrv_refresh_filename(BlockDriverState *bs);
338 
339 int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact,
340                                   PreallocMode prealloc, Error **errp);
341 int bdrv_truncate(BdrvChild *child, int64_t offset, bool exact,
342                   PreallocMode prealloc, Error **errp);
343 
344 int64_t bdrv_nb_sectors(BlockDriverState *bs);
345 int64_t bdrv_getlength(BlockDriverState *bs);
346 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
347 BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
348                                BlockDriverState *in_bs, Error **errp);
349 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
350 void bdrv_refresh_limits(BlockDriverState *bs, Error **errp);
351 int bdrv_commit(BlockDriverState *bs);
352 int bdrv_change_backing_file(BlockDriverState *bs,
353     const char *backing_file, const char *backing_fmt);
354 void bdrv_register(BlockDriver *bdrv);
355 int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
356                            const char *backing_file_str);
357 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
358                                     BlockDriverState *bs);
359 BlockDriverState *bdrv_find_base(BlockDriverState *bs);
360 bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base,
361                                   Error **errp);
362 int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base,
363                               Error **errp);
364 void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base);
365 
366 
367 typedef struct BdrvCheckResult {
368     int corruptions;
369     int leaks;
370     int check_errors;
371     int corruptions_fixed;
372     int leaks_fixed;
373     int64_t image_end_offset;
374     BlockFragInfo bfi;
375 } BdrvCheckResult;
376 
377 typedef enum {
378     BDRV_FIX_LEAKS    = 1,
379     BDRV_FIX_ERRORS   = 2,
380 } BdrvCheckMode;
381 
382 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
383 
384 /* The units of offset and total_work_size may be chosen arbitrarily by the
385  * block driver; total_work_size may change during the course of the amendment
386  * operation */
387 typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
388                                       int64_t total_work_size, void *opaque);
389 int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
390                        BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
391                        Error **errp);
392 
393 /* external snapshots */
394 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
395                                       BlockDriverState *candidate);
396 bool bdrv_is_first_non_filter(BlockDriverState *candidate);
397 
398 /* check if a named node can be replaced when doing drive-mirror */
399 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
400                                         const char *node_name, Error **errp);
401 
402 /* async block I/O */
403 void bdrv_aio_cancel(BlockAIOCB *acb);
404 void bdrv_aio_cancel_async(BlockAIOCB *acb);
405 
406 /* sg packet commands */
407 int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf);
408 
409 /* Invalidate any cached metadata used by image formats */
410 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp);
411 void bdrv_invalidate_cache_all(Error **errp);
412 int bdrv_inactivate_all(void);
413 
414 /* Ensure contents are flushed to disk.  */
415 int bdrv_flush(BlockDriverState *bs);
416 int coroutine_fn bdrv_co_flush(BlockDriverState *bs);
417 int bdrv_flush_all(void);
418 void bdrv_close_all(void);
419 void bdrv_drain(BlockDriverState *bs);
420 void coroutine_fn bdrv_co_drain(BlockDriverState *bs);
421 void bdrv_drain_all_begin(void);
422 void bdrv_drain_all_end(void);
423 void bdrv_drain_all(void);
424 
425 #define BDRV_POLL_WHILE(bs, cond) ({                       \
426     BlockDriverState *bs_ = (bs);                          \
427     AIO_WAIT_WHILE(bdrv_get_aio_context(bs_),              \
428                    cond); })
429 
430 int bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
431 int bdrv_co_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
432 int bdrv_has_zero_init_1(BlockDriverState *bs);
433 int bdrv_has_zero_init(BlockDriverState *bs);
434 int bdrv_has_zero_init_truncate(BlockDriverState *bs);
435 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs);
436 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
437 int bdrv_block_status(BlockDriverState *bs, int64_t offset,
438                       int64_t bytes, int64_t *pnum, int64_t *map,
439                       BlockDriverState **file);
440 int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
441                             int64_t offset, int64_t bytes, int64_t *pnum,
442                             int64_t *map, BlockDriverState **file);
443 int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
444                       int64_t *pnum);
445 int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
446                             bool include_base, int64_t offset, int64_t bytes,
447                             int64_t *pnum);
448 
449 bool bdrv_is_read_only(BlockDriverState *bs);
450 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
451                            bool ignore_allow_rdw, Error **errp);
452 int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg,
453                               Error **errp);
454 bool bdrv_is_writable(BlockDriverState *bs);
455 bool bdrv_is_sg(BlockDriverState *bs);
456 bool bdrv_is_inserted(BlockDriverState *bs);
457 void bdrv_lock_medium(BlockDriverState *bs, bool locked);
458 void bdrv_eject(BlockDriverState *bs, bool eject_flag);
459 const char *bdrv_get_format_name(BlockDriverState *bs);
460 BlockDriverState *bdrv_find_node(const char *node_name);
461 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp);
462 XDbgBlockGraph *bdrv_get_xdbg_block_graph(Error **errp);
463 BlockDriverState *bdrv_lookup_bs(const char *device,
464                                  const char *node_name,
465                                  Error **errp);
466 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
467 BlockDriverState *bdrv_next_node(BlockDriverState *bs);
468 BlockDriverState *bdrv_next_all_states(BlockDriverState *bs);
469 
470 typedef struct BdrvNextIterator {
471     enum {
472         BDRV_NEXT_BACKEND_ROOTS,
473         BDRV_NEXT_MONITOR_OWNED,
474     } phase;
475     BlockBackend *blk;
476     BlockDriverState *bs;
477 } BdrvNextIterator;
478 
479 BlockDriverState *bdrv_first(BdrvNextIterator *it);
480 BlockDriverState *bdrv_next(BdrvNextIterator *it);
481 void bdrv_next_cleanup(BdrvNextIterator *it);
482 
483 BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs);
484 bool bdrv_is_encrypted(BlockDriverState *bs);
485 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
486                          void *opaque, bool read_only);
487 const char *bdrv_get_node_name(const BlockDriverState *bs);
488 const char *bdrv_get_device_name(const BlockDriverState *bs);
489 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
490 int bdrv_get_flags(BlockDriverState *bs);
491 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
492 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs,
493                                           Error **errp);
494 BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs);
495 void bdrv_round_to_clusters(BlockDriverState *bs,
496                             int64_t offset, int64_t bytes,
497                             int64_t *cluster_offset,
498                             int64_t *cluster_bytes);
499 
500 void bdrv_get_backing_filename(BlockDriverState *bs,
501                                char *filename, int filename_size);
502 char *bdrv_get_full_backing_filename(BlockDriverState *bs, Error **errp);
503 char *bdrv_get_full_backing_filename_from_filename(const char *backed,
504                                                    const char *backing,
505                                                    Error **errp);
506 char *bdrv_dirname(BlockDriverState *bs, Error **errp);
507 
508 int path_has_protocol(const char *path);
509 int path_is_absolute(const char *path);
510 char *path_combine(const char *base_path, const char *filename);
511 
512 int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
513 int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
514 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
515                       int64_t pos, int size);
516 
517 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
518                       int64_t pos, int size);
519 
520 void bdrv_img_create(const char *filename, const char *fmt,
521                      const char *base_filename, const char *base_fmt,
522                      char *options, uint64_t img_size, int flags,
523                      bool quiet, Error **errp);
524 
525 /* Returns the alignment in bytes that is required so that no bounce buffer
526  * is required throughout the stack */
527 size_t bdrv_min_mem_align(BlockDriverState *bs);
528 /* Returns optimal alignment in bytes for bounce buffer */
529 size_t bdrv_opt_mem_align(BlockDriverState *bs);
530 void *qemu_blockalign(BlockDriverState *bs, size_t size);
531 void *qemu_blockalign0(BlockDriverState *bs, size_t size);
532 void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
533 void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
534 bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);
535 
536 void bdrv_enable_copy_on_read(BlockDriverState *bs);
537 void bdrv_disable_copy_on_read(BlockDriverState *bs);
538 
539 void bdrv_ref(BlockDriverState *bs);
540 void bdrv_unref(BlockDriverState *bs);
541 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child);
542 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
543                              BlockDriverState *child_bs,
544                              const char *child_name,
545                              const BdrvChildRole *child_role,
546                              Error **errp);
547 
548 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
549 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);
550 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason);
551 void bdrv_op_block_all(BlockDriverState *bs, Error *reason);
552 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason);
553 bool bdrv_op_blocker_is_empty(BlockDriverState *bs);
554 
555 #define BLKDBG_EVENT(child, evt) \
556     do { \
557         if (child) { \
558             bdrv_debug_event(child->bs, evt); \
559         } \
560     } while (0)
561 
562 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
563 
564 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
565                            const char *tag);
566 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag);
567 int bdrv_debug_resume(BlockDriverState *bs, const char *tag);
568 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag);
569 
570 /**
571  * bdrv_get_aio_context:
572  *
573  * Returns: the currently bound #AioContext
574  */
575 AioContext *bdrv_get_aio_context(BlockDriverState *bs);
576 
577 /**
578  * Transfer control to @co in the aio context of @bs
579  */
580 void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co);
581 
582 void bdrv_set_aio_context_ignore(BlockDriverState *bs,
583                                  AioContext *new_context, GSList **ignore);
584 int bdrv_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
585                              Error **errp);
586 int bdrv_child_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
587                                    BdrvChild *ignore_child, Error **errp);
588 bool bdrv_child_can_set_aio_context(BdrvChild *c, AioContext *ctx,
589                                     GSList **ignore, Error **errp);
590 bool bdrv_can_set_aio_context(BlockDriverState *bs, AioContext *ctx,
591                               GSList **ignore, Error **errp);
592 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
593 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
594 
595 void bdrv_io_plug(BlockDriverState *bs);
596 void bdrv_io_unplug(BlockDriverState *bs);
597 
598 /**
599  * bdrv_parent_drained_begin_single:
600  *
601  * Begin a quiesced section for the parent of @c. If @poll is true, wait for
602  * any pending activity to cease.
603  */
604 void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll);
605 
606 /**
607  * bdrv_parent_drained_end_single:
608  *
609  * End a quiesced section for the parent of @c.
610  *
611  * This polls @bs's AioContext until all scheduled sub-drained_ends
612  * have settled, which may result in graph changes.
613  */
614 void bdrv_parent_drained_end_single(BdrvChild *c);
615 
616 /**
617  * bdrv_drain_poll:
618  *
619  * Poll for pending requests in @bs, its parents (except for @ignore_parent),
620  * and if @recursive is true its children as well (used for subtree drain).
621  *
622  * If @ignore_bds_parents is true, parents that are BlockDriverStates must
623  * ignore the drain request because they will be drained separately (used for
624  * drain_all).
625  *
626  * This is part of bdrv_drained_begin.
627  */
628 bool bdrv_drain_poll(BlockDriverState *bs, bool recursive,
629                      BdrvChild *ignore_parent, bool ignore_bds_parents);
630 
631 /**
632  * bdrv_drained_begin:
633  *
634  * Begin a quiesced section for exclusive access to the BDS, by disabling
635  * external request sources including NBD server and device model. Note that
636  * this doesn't block timers or coroutines from submitting more requests, which
637  * means block_job_pause is still necessary.
638  *
639  * This function can be recursive.
640  */
641 void bdrv_drained_begin(BlockDriverState *bs);
642 
643 /**
644  * bdrv_do_drained_begin_quiesce:
645  *
646  * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already
647  * running requests to complete.
648  */
649 void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,
650                                    BdrvChild *parent, bool ignore_bds_parents);
651 
652 /**
653  * Like bdrv_drained_begin, but recursively begins a quiesced section for
654  * exclusive access to all child nodes as well.
655  */
656 void bdrv_subtree_drained_begin(BlockDriverState *bs);
657 
658 /**
659  * bdrv_drained_end:
660  *
661  * End a quiescent section started by bdrv_drained_begin().
662  *
663  * This polls @bs's AioContext until all scheduled sub-drained_ends
664  * have settled.  On one hand, that may result in graph changes.  On
665  * the other, this requires that the caller either runs in the main
666  * loop; or that all involved nodes (@bs and all of its parents) are
667  * in the caller's AioContext.
668  */
669 void bdrv_drained_end(BlockDriverState *bs);
670 
671 /**
672  * bdrv_drained_end_no_poll:
673  *
674  * Same as bdrv_drained_end(), but do not poll for the subgraph to
675  * actually become unquiesced.  Therefore, no graph changes will occur
676  * with this function.
677  *
678  * *drained_end_counter is incremented for every background operation
679  * that is scheduled, and will be decremented for every operation once
680  * it settles.  The caller must poll until it reaches 0.  The counter
681  * should be accessed using atomic operations only.
682  */
683 void bdrv_drained_end_no_poll(BlockDriverState *bs, int *drained_end_counter);
684 
685 /**
686  * End a quiescent section started by bdrv_subtree_drained_begin().
687  */
688 void bdrv_subtree_drained_end(BlockDriverState *bs);
689 
690 void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
691                     Error **errp);
692 void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
693 
694 bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
695                                      uint32_t granularity, Error **errp);
696 /**
697  *
698  * bdrv_register_buf/bdrv_unregister_buf:
699  *
700  * Register/unregister a buffer for I/O. For example, VFIO drivers are
701  * interested to know the memory areas that would later be used for I/O, so
702  * that they can prepare IOMMU mapping etc., to get better performance.
703  */
704 void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size);
705 void bdrv_unregister_buf(BlockDriverState *bs, void *host);
706 
707 /**
708  *
709  * bdrv_co_copy_range:
710  *
711  * Do offloaded copy between two children. If the operation is not implemented
712  * by the driver, or if the backend storage doesn't support it, a negative
713  * error code will be returned.
714  *
715  * Note: block layer doesn't emulate or fallback to a bounce buffer approach
716  * because usually the caller shouldn't attempt offloaded copy any more (e.g.
717  * calling copy_file_range(2)) after the first error, thus it should fall back
718  * to a read+write path in the caller level.
719  *
720  * @src: Source child to copy data from
721  * @src_offset: offset in @src image to read data
722  * @dst: Destination child to copy data to
723  * @dst_offset: offset in @dst image to write data
724  * @bytes: number of bytes to copy
725  * @flags: request flags. Supported flags:
726  *         BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero
727  *                               write on @dst as if bdrv_co_pwrite_zeroes is
728  *                               called. Used to simplify caller code, or
729  *                               during BlockDriver.bdrv_co_copy_range_from()
730  *                               recursion.
731  *         BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping
732  *                                   requests currently in flight.
733  *
734  * Returns: 0 if succeeded; negative error code if failed.
735  **/
736 int coroutine_fn bdrv_co_copy_range(BdrvChild *src, uint64_t src_offset,
737                                     BdrvChild *dst, uint64_t dst_offset,
738                                     uint64_t bytes, BdrvRequestFlags read_flags,
739                                     BdrvRequestFlags write_flags);
740 #endif
741