xref: /openbmc/qemu/include/block/block.h (revision 2d7ac0af)
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 BdrvChildClass BdrvChildClass;
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 this block driver only supports compressed writes
26      */
27     bool needs_compressed_writes;
28 } BlockDriverInfo;
29 
30 typedef struct BlockFragInfo {
31     uint64_t allocated_clusters;
32     uint64_t total_clusters;
33     uint64_t fragmented_clusters;
34     uint64_t compressed_clusters;
35 } BlockFragInfo;
36 
37 typedef enum {
38     BDRV_REQ_COPY_ON_READ       = 0x1,
39     BDRV_REQ_ZERO_WRITE         = 0x2,
40 
41     /*
42      * The BDRV_REQ_MAY_UNMAP flag is used in write_zeroes requests to indicate
43      * that the block driver should unmap (discard) blocks if it is guaranteed
44      * that the result will read back as zeroes. The flag is only passed to the
45      * driver if the block device is opened with BDRV_O_UNMAP.
46      */
47     BDRV_REQ_MAY_UNMAP          = 0x4,
48 
49     BDRV_REQ_FUA                = 0x10,
50     BDRV_REQ_WRITE_COMPRESSED   = 0x20,
51 
52     /* Signifies that this write request will not change the visible disk
53      * content. */
54     BDRV_REQ_WRITE_UNCHANGED    = 0x40,
55 
56     /*
57      * BDRV_REQ_SERIALISING forces request serialisation for writes.
58      * It is used to ensure that writes to the backing file of a backup process
59      * target cannot race with a read of the backup target that defers to the
60      * backing file.
61      *
62      * Note, that BDRV_REQ_SERIALISING is _not_ opposite in meaning to
63      * BDRV_REQ_NO_SERIALISING. A more descriptive name for the latter might be
64      * _DO_NOT_WAIT_FOR_SERIALISING, except that is too long.
65      */
66     BDRV_REQ_SERIALISING        = 0x80,
67 
68     /* Execute the request only if the operation can be offloaded or otherwise
69      * be executed efficiently, but return an error instead of using a slow
70      * fallback. */
71     BDRV_REQ_NO_FALLBACK        = 0x100,
72 
73     /*
74      * BDRV_REQ_PREFETCH may be used only together with BDRV_REQ_COPY_ON_READ
75      * on read request and means that caller doesn't really need data to be
76      * written to qiov parameter which may be NULL.
77      */
78     BDRV_REQ_PREFETCH  = 0x200,
79     /* Mask of valid flags */
80     BDRV_REQ_MASK               = 0x3ff,
81 } BdrvRequestFlags;
82 
83 typedef struct BlockSizes {
84     uint32_t phys;
85     uint32_t log;
86 } BlockSizes;
87 
88 typedef struct HDGeometry {
89     uint32_t heads;
90     uint32_t sectors;
91     uint32_t cylinders;
92 } HDGeometry;
93 
94 #define BDRV_O_RDWR        0x0002
95 #define BDRV_O_RESIZE      0x0004 /* request permission for resizing the node */
96 #define BDRV_O_SNAPSHOT    0x0008 /* open the file read only and save writes in a snapshot */
97 #define BDRV_O_TEMPORARY   0x0010 /* delete the file after use */
98 #define BDRV_O_NOCACHE     0x0020 /* do not use the host page cache */
99 #define BDRV_O_NATIVE_AIO  0x0080 /* use native AIO instead of the thread pool */
100 #define BDRV_O_NO_BACKING  0x0100 /* don't open the backing file */
101 #define BDRV_O_NO_FLUSH    0x0200 /* disable flushing on this disk */
102 #define BDRV_O_COPY_ON_READ 0x0400 /* copy read backing sectors into image */
103 #define BDRV_O_INACTIVE    0x0800  /* consistency hint for migration handoff */
104 #define BDRV_O_CHECK       0x1000  /* open solely for consistency check */
105 #define BDRV_O_ALLOW_RDWR  0x2000  /* allow reopen to change from r/o to r/w */
106 #define BDRV_O_UNMAP       0x4000  /* execute guest UNMAP/TRIM operations */
107 #define BDRV_O_PROTOCOL    0x8000  /* if no block driver is explicitly given:
108                                       select an appropriate protocol driver,
109                                       ignoring the format layer */
110 #define BDRV_O_NO_IO       0x10000 /* don't initialize for I/O */
111 #define BDRV_O_AUTO_RDONLY 0x20000 /* degrade to read-only if opening read-write fails */
112 #define BDRV_O_IO_URING    0x40000 /* use io_uring instead of the thread pool */
113 
114 #define BDRV_O_CACHE_MASK  (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH)
115 
116 
117 /* Option names of options parsed by the block layer */
118 
119 #define BDRV_OPT_CACHE_WB       "cache.writeback"
120 #define BDRV_OPT_CACHE_DIRECT   "cache.direct"
121 #define BDRV_OPT_CACHE_NO_FLUSH "cache.no-flush"
122 #define BDRV_OPT_READ_ONLY      "read-only"
123 #define BDRV_OPT_AUTO_READ_ONLY "auto-read-only"
124 #define BDRV_OPT_DISCARD        "discard"
125 #define BDRV_OPT_FORCE_SHARE    "force-share"
126 
127 
128 #define BDRV_SECTOR_BITS   9
129 #define BDRV_SECTOR_SIZE   (1ULL << BDRV_SECTOR_BITS)
130 
131 #define BDRV_REQUEST_MAX_SECTORS MIN_CONST(SIZE_MAX >> BDRV_SECTOR_BITS, \
132                                            INT_MAX >> BDRV_SECTOR_BITS)
133 #define BDRV_REQUEST_MAX_BYTES (BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS)
134 
135 /*
136  * Allocation status flags for bdrv_block_status() and friends.
137  *
138  * Public flags:
139  * BDRV_BLOCK_DATA: allocation for data at offset is tied to this layer
140  * BDRV_BLOCK_ZERO: offset reads as zero
141  * BDRV_BLOCK_OFFSET_VALID: an associated offset exists for accessing raw data
142  * BDRV_BLOCK_ALLOCATED: the content of the block is determined by this
143  *                       layer rather than any backing, set by block layer
144  * BDRV_BLOCK_EOF: the returned pnum covers through end of file for this
145  *                 layer, set by block layer
146  *
147  * Internal flags:
148  * BDRV_BLOCK_RAW: for use by passthrough drivers, such as raw, to request
149  *                 that the block layer recompute the answer from the returned
150  *                 BDS; must be accompanied by just BDRV_BLOCK_OFFSET_VALID.
151  * BDRV_BLOCK_RECURSE: request that the block layer will recursively search for
152  *                     zeroes in file child of current block node inside
153  *                     returned region. Only valid together with both
154  *                     BDRV_BLOCK_DATA and BDRV_BLOCK_OFFSET_VALID. Should not
155  *                     appear with BDRV_BLOCK_ZERO.
156  *
157  * If BDRV_BLOCK_OFFSET_VALID is set, the map parameter represents the
158  * host offset within the returned BDS that is allocated for the
159  * corresponding raw guest data.  However, whether that offset
160  * actually contains data also depends on BDRV_BLOCK_DATA, as follows:
161  *
162  * DATA ZERO OFFSET_VALID
163  *  t    t        t       sectors read as zero, returned file is zero at offset
164  *  t    f        t       sectors read as valid from file at offset
165  *  f    t        t       sectors preallocated, read as zero, returned file not
166  *                        necessarily zero at offset
167  *  f    f        t       sectors preallocated but read from backing_hd,
168  *                        returned file contains garbage at offset
169  *  t    t        f       sectors preallocated, read as zero, unknown offset
170  *  t    f        f       sectors read from unknown file or offset
171  *  f    t        f       not allocated or unknown offset, read as zero
172  *  f    f        f       not allocated or unknown offset, read from backing_hd
173  */
174 #define BDRV_BLOCK_DATA         0x01
175 #define BDRV_BLOCK_ZERO         0x02
176 #define BDRV_BLOCK_OFFSET_VALID 0x04
177 #define BDRV_BLOCK_RAW          0x08
178 #define BDRV_BLOCK_ALLOCATED    0x10
179 #define BDRV_BLOCK_EOF          0x20
180 #define BDRV_BLOCK_RECURSE      0x40
181 
182 typedef QTAILQ_HEAD(BlockReopenQueue, BlockReopenQueueEntry) BlockReopenQueue;
183 
184 typedef struct BDRVReopenState {
185     BlockDriverState *bs;
186     int flags;
187     BlockdevDetectZeroesOptions detect_zeroes;
188     bool backing_missing;
189     bool replace_backing_bs;  /* new_backing_bs is ignored if this is false */
190     BlockDriverState *new_backing_bs; /* If NULL then detach the current bs */
191     uint64_t perm, shared_perm;
192     QDict *options;
193     QDict *explicit_options;
194     void *opaque;
195 } BDRVReopenState;
196 
197 /*
198  * Block operation types
199  */
200 typedef enum BlockOpType {
201     BLOCK_OP_TYPE_BACKUP_SOURCE,
202     BLOCK_OP_TYPE_BACKUP_TARGET,
203     BLOCK_OP_TYPE_CHANGE,
204     BLOCK_OP_TYPE_COMMIT_SOURCE,
205     BLOCK_OP_TYPE_COMMIT_TARGET,
206     BLOCK_OP_TYPE_DATAPLANE,
207     BLOCK_OP_TYPE_DRIVE_DEL,
208     BLOCK_OP_TYPE_EJECT,
209     BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
210     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT,
211     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
212     BLOCK_OP_TYPE_MIRROR_SOURCE,
213     BLOCK_OP_TYPE_MIRROR_TARGET,
214     BLOCK_OP_TYPE_RESIZE,
215     BLOCK_OP_TYPE_STREAM,
216     BLOCK_OP_TYPE_REPLACE,
217     BLOCK_OP_TYPE_MAX,
218 } BlockOpType;
219 
220 /* Block node permission constants */
221 enum {
222     /**
223      * A user that has the "permission" of consistent reads is guaranteed that
224      * their view of the contents of the block device is complete and
225      * self-consistent, representing the contents of a disk at a specific
226      * point.
227      *
228      * For most block devices (including their backing files) this is true, but
229      * the property cannot be maintained in a few situations like for
230      * intermediate nodes of a commit block job.
231      */
232     BLK_PERM_CONSISTENT_READ    = 0x01,
233 
234     /** This permission is required to change the visible disk contents. */
235     BLK_PERM_WRITE              = 0x02,
236 
237     /**
238      * This permission (which is weaker than BLK_PERM_WRITE) is both enough and
239      * required for writes to the block node when the caller promises that
240      * the visible disk content doesn't change.
241      *
242      * As the BLK_PERM_WRITE permission is strictly stronger, either is
243      * sufficient to perform an unchanging write.
244      */
245     BLK_PERM_WRITE_UNCHANGED    = 0x04,
246 
247     /** This permission is required to change the size of a block node. */
248     BLK_PERM_RESIZE             = 0x08,
249 
250     /**
251      * This permission is required to change the node that this BdrvChild
252      * points to.
253      */
254     BLK_PERM_GRAPH_MOD          = 0x10,
255 
256     BLK_PERM_ALL                = 0x1f,
257 
258     DEFAULT_PERM_PASSTHROUGH    = BLK_PERM_CONSISTENT_READ
259                                  | BLK_PERM_WRITE
260                                  | BLK_PERM_WRITE_UNCHANGED
261                                  | BLK_PERM_RESIZE,
262 
263     DEFAULT_PERM_UNCHANGED      = BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH,
264 };
265 
266 /*
267  * Flags that parent nodes assign to child nodes to specify what kind of
268  * role(s) they take.
269  *
270  * At least one of DATA, METADATA, FILTERED, or COW must be set for
271  * every child.
272  */
273 enum BdrvChildRoleBits {
274     /*
275      * This child stores data.
276      * Any node may have an arbitrary number of such children.
277      */
278     BDRV_CHILD_DATA         = (1 << 0),
279 
280     /*
281      * This child stores metadata.
282      * Any node may have an arbitrary number of metadata-storing
283      * children.
284      */
285     BDRV_CHILD_METADATA     = (1 << 1),
286 
287     /*
288      * A child that always presents exactly the same visible data as
289      * the parent, e.g. by virtue of the parent forwarding all reads
290      * and writes.
291      * This flag is mutually exclusive with DATA, METADATA, and COW.
292      * Any node may have at most one filtered child at a time.
293      */
294     BDRV_CHILD_FILTERED     = (1 << 2),
295 
296     /*
297      * Child from which to read all data that isn’t allocated in the
298      * parent (i.e., the backing child); such data is copied to the
299      * parent through COW (and optionally COR).
300      * This field is mutually exclusive with DATA, METADATA, and
301      * FILTERED.
302      * Any node may have at most one such backing child at a time.
303      */
304     BDRV_CHILD_COW          = (1 << 3),
305 
306     /*
307      * The primary child.  For most drivers, this is the child whose
308      * filename applies best to the parent node.
309      * Any node may have at most one primary child at a time.
310      */
311     BDRV_CHILD_PRIMARY      = (1 << 4),
312 
313     /* Useful combination of flags */
314     BDRV_CHILD_IMAGE        = BDRV_CHILD_DATA
315                               | BDRV_CHILD_METADATA
316                               | BDRV_CHILD_PRIMARY,
317 };
318 
319 /* Mask of BdrvChildRoleBits values */
320 typedef unsigned int BdrvChildRole;
321 
322 char *bdrv_perm_names(uint64_t perm);
323 uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm);
324 
325 /* disk I/O throttling */
326 void bdrv_init(void);
327 void bdrv_init_with_whitelist(void);
328 bool bdrv_uses_whitelist(void);
329 int bdrv_is_whitelisted(BlockDriver *drv, bool read_only);
330 BlockDriver *bdrv_find_protocol(const char *filename,
331                                 bool allow_protocol_prefix,
332                                 Error **errp);
333 BlockDriver *bdrv_find_format(const char *format_name);
334 int bdrv_create(BlockDriver *drv, const char* filename,
335                 QemuOpts *opts, Error **errp);
336 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp);
337 
338 BlockDriverState *bdrv_new(void);
339 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
340                  Error **errp);
341 void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
342                        Error **errp);
343 
344 int bdrv_parse_aio(const char *mode, int *flags);
345 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough);
346 int bdrv_parse_discard_flags(const char *mode, int *flags);
347 BdrvChild *bdrv_open_child(const char *filename,
348                            QDict *options, const char *bdref_key,
349                            BlockDriverState* parent,
350                            const BdrvChildClass *child_class,
351                            BdrvChildRole child_role,
352                            bool allow_none, Error **errp);
353 BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp);
354 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
355                          Error **errp);
356 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
357                            const char *bdref_key, Error **errp);
358 BlockDriverState *bdrv_open(const char *filename, const char *reference,
359                             QDict *options, int flags, Error **errp);
360 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
361                                        int flags, Error **errp);
362 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
363                                     BlockDriverState *bs, QDict *options,
364                                     bool keep_old_opts);
365 int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp);
366 int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
367                               Error **errp);
368 int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
369                         BlockReopenQueue *queue, Error **errp);
370 void bdrv_reopen_commit(BDRVReopenState *reopen_state);
371 void bdrv_reopen_abort(BDRVReopenState *reopen_state);
372 int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
373                        int bytes, BdrvRequestFlags flags);
374 int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
375 int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes);
376 int bdrv_preadv(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
377 int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes);
378 int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
379 int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
380                      const void *buf, int count);
381 /*
382  * Efficiently zero a region of the disk image.  Note that this is a regular
383  * I/O request like read or write and should have a reasonable size.  This
384  * function is not suitable for zeroing the entire image in a single request
385  * because it may allocate memory for the entire region.
386  */
387 int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
388                                        int bytes, BdrvRequestFlags flags);
389 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
390     const char *backing_file);
391 void bdrv_refresh_filename(BlockDriverState *bs);
392 
393 int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact,
394                                   PreallocMode prealloc, BdrvRequestFlags flags,
395                                   Error **errp);
396 int bdrv_truncate(BdrvChild *child, int64_t offset, bool exact,
397                   PreallocMode prealloc, BdrvRequestFlags flags, Error **errp);
398 
399 int64_t bdrv_nb_sectors(BlockDriverState *bs);
400 int64_t bdrv_getlength(BlockDriverState *bs);
401 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
402 BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
403                                BlockDriverState *in_bs, Error **errp);
404 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
405 void bdrv_refresh_limits(BlockDriverState *bs, Error **errp);
406 int bdrv_commit(BlockDriverState *bs);
407 int bdrv_make_empty(BdrvChild *c, Error **errp);
408 int bdrv_change_backing_file(BlockDriverState *bs, const char *backing_file,
409                              const char *backing_fmt, bool warn);
410 void bdrv_register(BlockDriver *bdrv);
411 int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
412                            const char *backing_file_str);
413 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
414                                     BlockDriverState *bs);
415 BlockDriverState *bdrv_find_base(BlockDriverState *bs);
416 bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base,
417                                   Error **errp);
418 int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base,
419                               Error **errp);
420 void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base);
421 int coroutine_fn bdrv_co_delete_file(BlockDriverState *bs, Error **errp);
422 
423 
424 typedef struct BdrvCheckResult {
425     int corruptions;
426     int leaks;
427     int check_errors;
428     int corruptions_fixed;
429     int leaks_fixed;
430     int64_t image_end_offset;
431     BlockFragInfo bfi;
432 } BdrvCheckResult;
433 
434 typedef enum {
435     BDRV_FIX_LEAKS    = 1,
436     BDRV_FIX_ERRORS   = 2,
437 } BdrvCheckMode;
438 
439 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
440 
441 /* The units of offset and total_work_size may be chosen arbitrarily by the
442  * block driver; total_work_size may change during the course of the amendment
443  * operation */
444 typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
445                                       int64_t total_work_size, void *opaque);
446 int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
447                        BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
448                        bool force,
449                        Error **errp);
450 
451 /* check if a named node can be replaced when doing drive-mirror */
452 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
453                                         const char *node_name, Error **errp);
454 
455 /* async block I/O */
456 void bdrv_aio_cancel(BlockAIOCB *acb);
457 void bdrv_aio_cancel_async(BlockAIOCB *acb);
458 
459 /* sg packet commands */
460 int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf);
461 
462 /* Invalidate any cached metadata used by image formats */
463 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp);
464 void bdrv_invalidate_cache_all(Error **errp);
465 int bdrv_inactivate_all(void);
466 
467 /* Ensure contents are flushed to disk.  */
468 int bdrv_flush(BlockDriverState *bs);
469 int coroutine_fn bdrv_co_flush(BlockDriverState *bs);
470 int bdrv_flush_all(void);
471 void bdrv_close_all(void);
472 void bdrv_drain(BlockDriverState *bs);
473 void coroutine_fn bdrv_co_drain(BlockDriverState *bs);
474 void bdrv_drain_all_begin(void);
475 void bdrv_drain_all_end(void);
476 void bdrv_drain_all(void);
477 
478 #define BDRV_POLL_WHILE(bs, cond) ({                       \
479     BlockDriverState *bs_ = (bs);                          \
480     AIO_WAIT_WHILE(bdrv_get_aio_context(bs_),              \
481                    cond); })
482 
483 int bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
484 int bdrv_co_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
485 int bdrv_has_zero_init_1(BlockDriverState *bs);
486 int bdrv_has_zero_init(BlockDriverState *bs);
487 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
488 int bdrv_block_status(BlockDriverState *bs, int64_t offset,
489                       int64_t bytes, int64_t *pnum, int64_t *map,
490                       BlockDriverState **file);
491 int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
492                             int64_t offset, int64_t bytes, int64_t *pnum,
493                             int64_t *map, BlockDriverState **file);
494 int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
495                       int64_t *pnum);
496 int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
497                             bool include_base, int64_t offset, int64_t bytes,
498                             int64_t *pnum);
499 
500 bool bdrv_is_read_only(BlockDriverState *bs);
501 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
502                            bool ignore_allow_rdw, Error **errp);
503 int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg,
504                               Error **errp);
505 bool bdrv_is_writable(BlockDriverState *bs);
506 bool bdrv_is_sg(BlockDriverState *bs);
507 bool bdrv_is_inserted(BlockDriverState *bs);
508 void bdrv_lock_medium(BlockDriverState *bs, bool locked);
509 void bdrv_eject(BlockDriverState *bs, bool eject_flag);
510 const char *bdrv_get_format_name(BlockDriverState *bs);
511 BlockDriverState *bdrv_find_node(const char *node_name);
512 BlockDeviceInfoList *bdrv_named_nodes_list(bool flat, Error **errp);
513 XDbgBlockGraph *bdrv_get_xdbg_block_graph(Error **errp);
514 BlockDriverState *bdrv_lookup_bs(const char *device,
515                                  const char *node_name,
516                                  Error **errp);
517 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
518 BlockDriverState *bdrv_next_node(BlockDriverState *bs);
519 BlockDriverState *bdrv_next_all_states(BlockDriverState *bs);
520 
521 typedef struct BdrvNextIterator {
522     enum {
523         BDRV_NEXT_BACKEND_ROOTS,
524         BDRV_NEXT_MONITOR_OWNED,
525     } phase;
526     BlockBackend *blk;
527     BlockDriverState *bs;
528 } BdrvNextIterator;
529 
530 BlockDriverState *bdrv_first(BdrvNextIterator *it);
531 BlockDriverState *bdrv_next(BdrvNextIterator *it);
532 void bdrv_next_cleanup(BdrvNextIterator *it);
533 
534 BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs);
535 bool bdrv_is_encrypted(BlockDriverState *bs);
536 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
537                          void *opaque, bool read_only);
538 const char *bdrv_get_node_name(const BlockDriverState *bs);
539 const char *bdrv_get_device_name(const BlockDriverState *bs);
540 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
541 int bdrv_get_flags(BlockDriverState *bs);
542 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
543 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs,
544                                           Error **errp);
545 BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs);
546 void bdrv_round_to_clusters(BlockDriverState *bs,
547                             int64_t offset, int64_t bytes,
548                             int64_t *cluster_offset,
549                             int64_t *cluster_bytes);
550 
551 void bdrv_get_backing_filename(BlockDriverState *bs,
552                                char *filename, int filename_size);
553 char *bdrv_get_full_backing_filename(BlockDriverState *bs, Error **errp);
554 char *bdrv_get_full_backing_filename_from_filename(const char *backed,
555                                                    const char *backing,
556                                                    Error **errp);
557 char *bdrv_dirname(BlockDriverState *bs, Error **errp);
558 
559 int path_has_protocol(const char *path);
560 int path_is_absolute(const char *path);
561 char *path_combine(const char *base_path, const char *filename);
562 
563 int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
564 int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
565 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
566                       int64_t pos, int size);
567 
568 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
569                       int64_t pos, int size);
570 
571 void bdrv_img_create(const char *filename, const char *fmt,
572                      const char *base_filename, const char *base_fmt,
573                      char *options, uint64_t img_size, int flags,
574                      bool quiet, Error **errp);
575 
576 /* Returns the alignment in bytes that is required so that no bounce buffer
577  * is required throughout the stack */
578 size_t bdrv_min_mem_align(BlockDriverState *bs);
579 /* Returns optimal alignment in bytes for bounce buffer */
580 size_t bdrv_opt_mem_align(BlockDriverState *bs);
581 void *qemu_blockalign(BlockDriverState *bs, size_t size);
582 void *qemu_blockalign0(BlockDriverState *bs, size_t size);
583 void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
584 void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
585 bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);
586 
587 void bdrv_enable_copy_on_read(BlockDriverState *bs);
588 void bdrv_disable_copy_on_read(BlockDriverState *bs);
589 
590 void bdrv_ref(BlockDriverState *bs);
591 void bdrv_unref(BlockDriverState *bs);
592 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child);
593 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
594                              BlockDriverState *child_bs,
595                              const char *child_name,
596                              const BdrvChildClass *child_class,
597                              BdrvChildRole child_role,
598                              Error **errp);
599 
600 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
601 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);
602 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason);
603 void bdrv_op_block_all(BlockDriverState *bs, Error *reason);
604 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason);
605 bool bdrv_op_blocker_is_empty(BlockDriverState *bs);
606 
607 #define BLKDBG_EVENT(child, evt) \
608     do { \
609         if (child) { \
610             bdrv_debug_event(child->bs, evt); \
611         } \
612     } while (0)
613 
614 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
615 
616 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
617                            const char *tag);
618 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag);
619 int bdrv_debug_resume(BlockDriverState *bs, const char *tag);
620 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag);
621 
622 /**
623  * bdrv_get_aio_context:
624  *
625  * Returns: the currently bound #AioContext
626  */
627 AioContext *bdrv_get_aio_context(BlockDriverState *bs);
628 
629 /**
630  * Transfer control to @co in the aio context of @bs
631  */
632 void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co);
633 
634 void bdrv_set_aio_context_ignore(BlockDriverState *bs,
635                                  AioContext *new_context, GSList **ignore);
636 int bdrv_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
637                              Error **errp);
638 int bdrv_child_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
639                                    BdrvChild *ignore_child, Error **errp);
640 bool bdrv_child_can_set_aio_context(BdrvChild *c, AioContext *ctx,
641                                     GSList **ignore, Error **errp);
642 bool bdrv_can_set_aio_context(BlockDriverState *bs, AioContext *ctx,
643                               GSList **ignore, Error **errp);
644 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
645 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
646 
647 void bdrv_io_plug(BlockDriverState *bs);
648 void bdrv_io_unplug(BlockDriverState *bs);
649 
650 /**
651  * bdrv_parent_drained_begin_single:
652  *
653  * Begin a quiesced section for the parent of @c. If @poll is true, wait for
654  * any pending activity to cease.
655  */
656 void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll);
657 
658 /**
659  * bdrv_parent_drained_end_single:
660  *
661  * End a quiesced section for the parent of @c.
662  *
663  * This polls @bs's AioContext until all scheduled sub-drained_ends
664  * have settled, which may result in graph changes.
665  */
666 void bdrv_parent_drained_end_single(BdrvChild *c);
667 
668 /**
669  * bdrv_drain_poll:
670  *
671  * Poll for pending requests in @bs, its parents (except for @ignore_parent),
672  * and if @recursive is true its children as well (used for subtree drain).
673  *
674  * If @ignore_bds_parents is true, parents that are BlockDriverStates must
675  * ignore the drain request because they will be drained separately (used for
676  * drain_all).
677  *
678  * This is part of bdrv_drained_begin.
679  */
680 bool bdrv_drain_poll(BlockDriverState *bs, bool recursive,
681                      BdrvChild *ignore_parent, bool ignore_bds_parents);
682 
683 /**
684  * bdrv_drained_begin:
685  *
686  * Begin a quiesced section for exclusive access to the BDS, by disabling
687  * external request sources including NBD server and device model. Note that
688  * this doesn't block timers or coroutines from submitting more requests, which
689  * means block_job_pause is still necessary.
690  *
691  * This function can be recursive.
692  */
693 void bdrv_drained_begin(BlockDriverState *bs);
694 
695 /**
696  * bdrv_do_drained_begin_quiesce:
697  *
698  * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already
699  * running requests to complete.
700  */
701 void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,
702                                    BdrvChild *parent, bool ignore_bds_parents);
703 
704 /**
705  * Like bdrv_drained_begin, but recursively begins a quiesced section for
706  * exclusive access to all child nodes as well.
707  */
708 void bdrv_subtree_drained_begin(BlockDriverState *bs);
709 
710 /**
711  * bdrv_drained_end:
712  *
713  * End a quiescent section started by bdrv_drained_begin().
714  *
715  * This polls @bs's AioContext until all scheduled sub-drained_ends
716  * have settled.  On one hand, that may result in graph changes.  On
717  * the other, this requires that the caller either runs in the main
718  * loop; or that all involved nodes (@bs and all of its parents) are
719  * in the caller's AioContext.
720  */
721 void bdrv_drained_end(BlockDriverState *bs);
722 
723 /**
724  * bdrv_drained_end_no_poll:
725  *
726  * Same as bdrv_drained_end(), but do not poll for the subgraph to
727  * actually become unquiesced.  Therefore, no graph changes will occur
728  * with this function.
729  *
730  * *drained_end_counter is incremented for every background operation
731  * that is scheduled, and will be decremented for every operation once
732  * it settles.  The caller must poll until it reaches 0.  The counter
733  * should be accessed using atomic operations only.
734  */
735 void bdrv_drained_end_no_poll(BlockDriverState *bs, int *drained_end_counter);
736 
737 /**
738  * End a quiescent section started by bdrv_subtree_drained_begin().
739  */
740 void bdrv_subtree_drained_end(BlockDriverState *bs);
741 
742 void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
743                     Error **errp);
744 void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
745 
746 bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
747                                      uint32_t granularity, Error **errp);
748 /**
749  *
750  * bdrv_register_buf/bdrv_unregister_buf:
751  *
752  * Register/unregister a buffer for I/O. For example, VFIO drivers are
753  * interested to know the memory areas that would later be used for I/O, so
754  * that they can prepare IOMMU mapping etc., to get better performance.
755  */
756 void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size);
757 void bdrv_unregister_buf(BlockDriverState *bs, void *host);
758 
759 /**
760  *
761  * bdrv_co_copy_range:
762  *
763  * Do offloaded copy between two children. If the operation is not implemented
764  * by the driver, or if the backend storage doesn't support it, a negative
765  * error code will be returned.
766  *
767  * Note: block layer doesn't emulate or fallback to a bounce buffer approach
768  * because usually the caller shouldn't attempt offloaded copy any more (e.g.
769  * calling copy_file_range(2)) after the first error, thus it should fall back
770  * to a read+write path in the caller level.
771  *
772  * @src: Source child to copy data from
773  * @src_offset: offset in @src image to read data
774  * @dst: Destination child to copy data to
775  * @dst_offset: offset in @dst image to write data
776  * @bytes: number of bytes to copy
777  * @flags: request flags. Supported flags:
778  *         BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero
779  *                               write on @dst as if bdrv_co_pwrite_zeroes is
780  *                               called. Used to simplify caller code, or
781  *                               during BlockDriver.bdrv_co_copy_range_from()
782  *                               recursion.
783  *         BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping
784  *                                   requests currently in flight.
785  *
786  * Returns: 0 if succeeded; negative error code if failed.
787  **/
788 int coroutine_fn bdrv_co_copy_range(BdrvChild *src, uint64_t src_offset,
789                                     BdrvChild *dst, uint64_t dst_offset,
790                                     uint64_t bytes, BdrvRequestFlags read_flags,
791                                     BdrvRequestFlags write_flags);
792 #endif
793