xref: /qemu/include/block/block.h (revision dc03272d)
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     /* The BDRV_REQ_MAY_UNMAP flag is used to indicate that the block driver
47      * is allowed to optimize a write zeroes request by unmapping (discarding)
48      * blocks if it is guaranteed that the result will read back as
49      * zeroes. The flag is only passed to the driver if the block device is
50      * opened with BDRV_O_UNMAP.
51      */
52     BDRV_REQ_MAY_UNMAP          = 0x4,
53     BDRV_REQ_NO_SERIALISING     = 0x8,
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     /* Mask of valid flags */
62     BDRV_REQ_MASK               = 0x7f,
63 } BdrvRequestFlags;
64 
65 typedef struct BlockSizes {
66     uint32_t phys;
67     uint32_t log;
68 } BlockSizes;
69 
70 typedef struct HDGeometry {
71     uint32_t heads;
72     uint32_t sectors;
73     uint32_t cylinders;
74 } HDGeometry;
75 
76 #define BDRV_O_RDWR        0x0002
77 #define BDRV_O_RESIZE      0x0004 /* request permission for resizing the node */
78 #define BDRV_O_SNAPSHOT    0x0008 /* open the file read only and save writes in a snapshot */
79 #define BDRV_O_TEMPORARY   0x0010 /* delete the file after use */
80 #define BDRV_O_NOCACHE     0x0020 /* do not use the host page cache */
81 #define BDRV_O_NATIVE_AIO  0x0080 /* use native AIO instead of the thread pool */
82 #define BDRV_O_NO_BACKING  0x0100 /* don't open the backing file */
83 #define BDRV_O_NO_FLUSH    0x0200 /* disable flushing on this disk */
84 #define BDRV_O_COPY_ON_READ 0x0400 /* copy read backing sectors into image */
85 #define BDRV_O_INACTIVE    0x0800  /* consistency hint for migration handoff */
86 #define BDRV_O_CHECK       0x1000  /* open solely for consistency check */
87 #define BDRV_O_ALLOW_RDWR  0x2000  /* allow reopen to change from r/o to r/w */
88 #define BDRV_O_UNMAP       0x4000  /* execute guest UNMAP/TRIM operations */
89 #define BDRV_O_PROTOCOL    0x8000  /* if no block driver is explicitly given:
90                                       select an appropriate protocol driver,
91                                       ignoring the format layer */
92 #define BDRV_O_NO_IO       0x10000 /* don't initialize for I/O */
93 
94 #define BDRV_O_CACHE_MASK  (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH)
95 
96 
97 /* Option names of options parsed by the block layer */
98 
99 #define BDRV_OPT_CACHE_WB       "cache.writeback"
100 #define BDRV_OPT_CACHE_DIRECT   "cache.direct"
101 #define BDRV_OPT_CACHE_NO_FLUSH "cache.no-flush"
102 #define BDRV_OPT_READ_ONLY      "read-only"
103 #define BDRV_OPT_DISCARD        "discard"
104 #define BDRV_OPT_FORCE_SHARE    "force-share"
105 
106 
107 #define BDRV_SECTOR_BITS   9
108 #define BDRV_SECTOR_SIZE   (1ULL << BDRV_SECTOR_BITS)
109 #define BDRV_SECTOR_MASK   ~(BDRV_SECTOR_SIZE - 1)
110 
111 #define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \
112                                      INT_MAX >> BDRV_SECTOR_BITS)
113 #define BDRV_REQUEST_MAX_BYTES (BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS)
114 
115 /*
116  * Allocation status flags for bdrv_block_status() and friends.
117  *
118  * Public flags:
119  * BDRV_BLOCK_DATA: allocation for data at offset is tied to this layer
120  * BDRV_BLOCK_ZERO: offset reads as zero
121  * BDRV_BLOCK_OFFSET_VALID: an associated offset exists for accessing raw data
122  * BDRV_BLOCK_ALLOCATED: the content of the block is determined by this
123  *                       layer rather than any backing, set by block layer
124  * BDRV_BLOCK_EOF: the returned pnum covers through end of file for this
125  *                 layer, set by block layer
126  *
127  * Internal flag:
128  * BDRV_BLOCK_RAW: for use by passthrough drivers, such as raw, to request
129  *                 that the block layer recompute the answer from the returned
130  *                 BDS; must be accompanied by just BDRV_BLOCK_OFFSET_VALID.
131  *
132  * If BDRV_BLOCK_OFFSET_VALID is set, the map parameter represents the
133  * host offset within the returned BDS that is allocated for the
134  * corresponding raw guest data.  However, whether that offset
135  * actually contains data also depends on BDRV_BLOCK_DATA, as follows:
136  *
137  * DATA ZERO OFFSET_VALID
138  *  t    t        t       sectors read as zero, returned file is zero at offset
139  *  t    f        t       sectors read as valid from file at offset
140  *  f    t        t       sectors preallocated, read as zero, returned file not
141  *                        necessarily zero at offset
142  *  f    f        t       sectors preallocated but read from backing_hd,
143  *                        returned file contains garbage at offset
144  *  t    t        f       sectors preallocated, read as zero, unknown offset
145  *  t    f        f       sectors read from unknown file or offset
146  *  f    t        f       not allocated or unknown offset, read as zero
147  *  f    f        f       not allocated or unknown offset, read from backing_hd
148  */
149 #define BDRV_BLOCK_DATA         0x01
150 #define BDRV_BLOCK_ZERO         0x02
151 #define BDRV_BLOCK_OFFSET_VALID 0x04
152 #define BDRV_BLOCK_RAW          0x08
153 #define BDRV_BLOCK_ALLOCATED    0x10
154 #define BDRV_BLOCK_EOF          0x20
155 #define BDRV_BLOCK_OFFSET_MASK  BDRV_SECTOR_MASK
156 
157 typedef QSIMPLEQ_HEAD(BlockReopenQueue, BlockReopenQueueEntry) BlockReopenQueue;
158 
159 typedef struct BDRVReopenState {
160     BlockDriverState *bs;
161     int flags;
162     uint64_t perm, shared_perm;
163     QDict *options;
164     QDict *explicit_options;
165     void *opaque;
166 } BDRVReopenState;
167 
168 /*
169  * Block operation types
170  */
171 typedef enum BlockOpType {
172     BLOCK_OP_TYPE_BACKUP_SOURCE,
173     BLOCK_OP_TYPE_BACKUP_TARGET,
174     BLOCK_OP_TYPE_CHANGE,
175     BLOCK_OP_TYPE_COMMIT_SOURCE,
176     BLOCK_OP_TYPE_COMMIT_TARGET,
177     BLOCK_OP_TYPE_DATAPLANE,
178     BLOCK_OP_TYPE_DRIVE_DEL,
179     BLOCK_OP_TYPE_EJECT,
180     BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
181     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT,
182     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
183     BLOCK_OP_TYPE_MIRROR_SOURCE,
184     BLOCK_OP_TYPE_MIRROR_TARGET,
185     BLOCK_OP_TYPE_RESIZE,
186     BLOCK_OP_TYPE_STREAM,
187     BLOCK_OP_TYPE_REPLACE,
188     BLOCK_OP_TYPE_MAX,
189 } BlockOpType;
190 
191 /* Block node permission constants */
192 enum {
193     /**
194      * A user that has the "permission" of consistent reads is guaranteed that
195      * their view of the contents of the block device is complete and
196      * self-consistent, representing the contents of a disk at a specific
197      * point.
198      *
199      * For most block devices (including their backing files) this is true, but
200      * the property cannot be maintained in a few situations like for
201      * intermediate nodes of a commit block job.
202      */
203     BLK_PERM_CONSISTENT_READ    = 0x01,
204 
205     /** This permission is required to change the visible disk contents. */
206     BLK_PERM_WRITE              = 0x02,
207 
208     /**
209      * This permission (which is weaker than BLK_PERM_WRITE) is both enough and
210      * required for writes to the block node when the caller promises that
211      * the visible disk content doesn't change.
212      *
213      * As the BLK_PERM_WRITE permission is strictly stronger, either is
214      * sufficient to perform an unchanging write.
215      */
216     BLK_PERM_WRITE_UNCHANGED    = 0x04,
217 
218     /** This permission is required to change the size of a block node. */
219     BLK_PERM_RESIZE             = 0x08,
220 
221     /**
222      * This permission is required to change the node that this BdrvChild
223      * points to.
224      */
225     BLK_PERM_GRAPH_MOD          = 0x10,
226 
227     BLK_PERM_ALL                = 0x1f,
228 };
229 
230 char *bdrv_perm_names(uint64_t perm);
231 
232 /* disk I/O throttling */
233 void bdrv_init(void);
234 void bdrv_init_with_whitelist(void);
235 bool bdrv_uses_whitelist(void);
236 int bdrv_is_whitelisted(BlockDriver *drv, bool read_only);
237 BlockDriver *bdrv_find_protocol(const char *filename,
238                                 bool allow_protocol_prefix,
239                                 Error **errp);
240 BlockDriver *bdrv_find_format(const char *format_name);
241 int bdrv_create(BlockDriver *drv, const char* filename,
242                 QemuOpts *opts, Error **errp);
243 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp);
244 BlockDriverState *bdrv_new(void);
245 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
246                  Error **errp);
247 void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
248                        Error **errp);
249 
250 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough);
251 int bdrv_parse_discard_flags(const char *mode, int *flags);
252 BdrvChild *bdrv_open_child(const char *filename,
253                            QDict *options, const char *bdref_key,
254                            BlockDriverState* parent,
255                            const BdrvChildRole *child_role,
256                            bool allow_none, Error **errp);
257 BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp);
258 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
259                          Error **errp);
260 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
261                            const char *bdref_key, Error **errp);
262 BlockDriverState *bdrv_open(const char *filename, const char *reference,
263                             QDict *options, int flags, Error **errp);
264 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
265                                        int flags, Error **errp);
266 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
267                                     BlockDriverState *bs,
268                                     QDict *options, int flags);
269 int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **errp);
270 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp);
271 int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
272                         BlockReopenQueue *queue, Error **errp);
273 void bdrv_reopen_commit(BDRVReopenState *reopen_state);
274 void bdrv_reopen_abort(BDRVReopenState *reopen_state);
275 int bdrv_read(BdrvChild *child, int64_t sector_num,
276               uint8_t *buf, int nb_sectors);
277 int bdrv_write(BdrvChild *child, int64_t sector_num,
278                const uint8_t *buf, int nb_sectors);
279 int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
280                        int bytes, BdrvRequestFlags flags);
281 int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
282 int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes);
283 int bdrv_preadv(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
284 int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes);
285 int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
286 int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
287                      const void *buf, int count);
288 int coroutine_fn bdrv_co_readv(BdrvChild *child, int64_t sector_num,
289                                int nb_sectors, QEMUIOVector *qiov);
290 int coroutine_fn bdrv_co_writev(BdrvChild *child, int64_t sector_num,
291                                int nb_sectors, QEMUIOVector *qiov);
292 /*
293  * Efficiently zero a region of the disk image.  Note that this is a regular
294  * I/O request like read or write and should have a reasonable size.  This
295  * function is not suitable for zeroing the entire image in a single request
296  * because it may allocate memory for the entire region.
297  */
298 int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
299                                        int bytes, BdrvRequestFlags flags);
300 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
301     const char *backing_file);
302 void bdrv_refresh_filename(BlockDriverState *bs);
303 int bdrv_truncate(BdrvChild *child, int64_t offset, PreallocMode prealloc,
304                   Error **errp);
305 int64_t bdrv_nb_sectors(BlockDriverState *bs);
306 int64_t bdrv_getlength(BlockDriverState *bs);
307 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
308 BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
309                                BlockDriverState *in_bs, Error **errp);
310 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
311 void bdrv_refresh_limits(BlockDriverState *bs, Error **errp);
312 int bdrv_commit(BlockDriverState *bs);
313 int bdrv_change_backing_file(BlockDriverState *bs,
314     const char *backing_file, const char *backing_fmt);
315 void bdrv_register(BlockDriver *bdrv);
316 int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
317                            const char *backing_file_str);
318 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
319                                     BlockDriverState *bs);
320 BlockDriverState *bdrv_find_base(BlockDriverState *bs);
321 
322 
323 typedef struct BdrvCheckResult {
324     int corruptions;
325     int leaks;
326     int check_errors;
327     int corruptions_fixed;
328     int leaks_fixed;
329     int64_t image_end_offset;
330     BlockFragInfo bfi;
331 } BdrvCheckResult;
332 
333 typedef enum {
334     BDRV_FIX_LEAKS    = 1,
335     BDRV_FIX_ERRORS   = 2,
336 } BdrvCheckMode;
337 
338 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
339 
340 /* The units of offset and total_work_size may be chosen arbitrarily by the
341  * block driver; total_work_size may change during the course of the amendment
342  * operation */
343 typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
344                                       int64_t total_work_size, void *opaque);
345 int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
346                        BlockDriverAmendStatusCB *status_cb, void *cb_opaque);
347 
348 /* external snapshots */
349 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
350                                       BlockDriverState *candidate);
351 bool bdrv_is_first_non_filter(BlockDriverState *candidate);
352 
353 /* check if a named node can be replaced when doing drive-mirror */
354 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
355                                         const char *node_name, Error **errp);
356 
357 /* async block I/O */
358 void bdrv_aio_cancel(BlockAIOCB *acb);
359 void bdrv_aio_cancel_async(BlockAIOCB *acb);
360 
361 /* sg packet commands */
362 int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf);
363 
364 /* Invalidate any cached metadata used by image formats */
365 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp);
366 void bdrv_invalidate_cache_all(Error **errp);
367 int bdrv_inactivate_all(void);
368 
369 /* Ensure contents are flushed to disk.  */
370 int bdrv_flush(BlockDriverState *bs);
371 int coroutine_fn bdrv_co_flush(BlockDriverState *bs);
372 int bdrv_flush_all(void);
373 void bdrv_close_all(void);
374 void bdrv_drain(BlockDriverState *bs);
375 void coroutine_fn bdrv_co_drain(BlockDriverState *bs);
376 void bdrv_drain_all_begin(void);
377 void bdrv_drain_all_end(void);
378 void bdrv_drain_all(void);
379 
380 /* Returns NULL when bs == NULL */
381 AioWait *bdrv_get_aio_wait(BlockDriverState *bs);
382 
383 #define BDRV_POLL_WHILE(bs, cond) ({                       \
384     BlockDriverState *bs_ = (bs);                          \
385     AIO_WAIT_WHILE(bdrv_get_aio_wait(bs_),                 \
386                    bdrv_get_aio_context(bs_),              \
387                    cond); })
388 
389 int bdrv_pdiscard(BlockDriverState *bs, int64_t offset, int bytes);
390 int bdrv_co_pdiscard(BlockDriverState *bs, int64_t offset, int bytes);
391 int bdrv_has_zero_init_1(BlockDriverState *bs);
392 int bdrv_has_zero_init(BlockDriverState *bs);
393 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs);
394 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
395 int bdrv_block_status(BlockDriverState *bs, int64_t offset,
396                       int64_t bytes, int64_t *pnum, int64_t *map,
397                       BlockDriverState **file);
398 int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
399                             int64_t offset, int64_t bytes, int64_t *pnum,
400                             int64_t *map, BlockDriverState **file);
401 int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
402                       int64_t *pnum);
403 int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
404                             int64_t offset, int64_t bytes, int64_t *pnum);
405 
406 bool bdrv_is_read_only(BlockDriverState *bs);
407 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
408                            bool ignore_allow_rdw, Error **errp);
409 int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp);
410 bool bdrv_is_sg(BlockDriverState *bs);
411 bool bdrv_is_inserted(BlockDriverState *bs);
412 void bdrv_lock_medium(BlockDriverState *bs, bool locked);
413 void bdrv_eject(BlockDriverState *bs, bool eject_flag);
414 const char *bdrv_get_format_name(BlockDriverState *bs);
415 BlockDriverState *bdrv_find_node(const char *node_name);
416 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp);
417 BlockDriverState *bdrv_lookup_bs(const char *device,
418                                  const char *node_name,
419                                  Error **errp);
420 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
421 BlockDriverState *bdrv_next_node(BlockDriverState *bs);
422 
423 typedef struct BdrvNextIterator {
424     enum {
425         BDRV_NEXT_BACKEND_ROOTS,
426         BDRV_NEXT_MONITOR_OWNED,
427     } phase;
428     BlockBackend *blk;
429     BlockDriverState *bs;
430 } BdrvNextIterator;
431 
432 BlockDriverState *bdrv_first(BdrvNextIterator *it);
433 BlockDriverState *bdrv_next(BdrvNextIterator *it);
434 void bdrv_next_cleanup(BdrvNextIterator *it);
435 
436 BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs);
437 bool bdrv_is_encrypted(BlockDriverState *bs);
438 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
439                          void *opaque);
440 const char *bdrv_get_node_name(const BlockDriverState *bs);
441 const char *bdrv_get_device_name(const BlockDriverState *bs);
442 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
443 int bdrv_get_flags(BlockDriverState *bs);
444 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
445 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs);
446 void bdrv_round_to_clusters(BlockDriverState *bs,
447                             int64_t offset, int64_t bytes,
448                             int64_t *cluster_offset,
449                             int64_t *cluster_bytes);
450 
451 const char *bdrv_get_encrypted_filename(BlockDriverState *bs);
452 void bdrv_get_backing_filename(BlockDriverState *bs,
453                                char *filename, int filename_size);
454 void bdrv_get_full_backing_filename(BlockDriverState *bs,
455                                     char *dest, size_t sz, Error **errp);
456 void bdrv_get_full_backing_filename_from_filename(const char *backed,
457                                                   const char *backing,
458                                                   char *dest, size_t sz,
459                                                   Error **errp);
460 
461 int path_has_protocol(const char *path);
462 int path_is_absolute(const char *path);
463 void path_combine(char *dest, int dest_size,
464                   const char *base_path,
465                   const char *filename);
466 
467 int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
468 int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
469 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
470                       int64_t pos, int size);
471 
472 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
473                       int64_t pos, int size);
474 
475 void bdrv_img_create(const char *filename, const char *fmt,
476                      const char *base_filename, const char *base_fmt,
477                      char *options, uint64_t img_size, int flags,
478                      bool quiet, Error **errp);
479 
480 /* Returns the alignment in bytes that is required so that no bounce buffer
481  * is required throughout the stack */
482 size_t bdrv_min_mem_align(BlockDriverState *bs);
483 /* Returns optimal alignment in bytes for bounce buffer */
484 size_t bdrv_opt_mem_align(BlockDriverState *bs);
485 void *qemu_blockalign(BlockDriverState *bs, size_t size);
486 void *qemu_blockalign0(BlockDriverState *bs, size_t size);
487 void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
488 void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
489 bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);
490 
491 void bdrv_enable_copy_on_read(BlockDriverState *bs);
492 void bdrv_disable_copy_on_read(BlockDriverState *bs);
493 
494 void bdrv_ref(BlockDriverState *bs);
495 void bdrv_unref(BlockDriverState *bs);
496 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child);
497 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
498                              BlockDriverState *child_bs,
499                              const char *child_name,
500                              const BdrvChildRole *child_role,
501                              Error **errp);
502 
503 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
504 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);
505 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason);
506 void bdrv_op_block_all(BlockDriverState *bs, Error *reason);
507 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason);
508 bool bdrv_op_blocker_is_empty(BlockDriverState *bs);
509 
510 #define BLKDBG_EVENT(child, evt) \
511     do { \
512         if (child) { \
513             bdrv_debug_event(child->bs, evt); \
514         } \
515     } while (0)
516 
517 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
518 
519 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
520                            const char *tag);
521 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag);
522 int bdrv_debug_resume(BlockDriverState *bs, const char *tag);
523 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag);
524 
525 /**
526  * bdrv_get_aio_context:
527  *
528  * Returns: the currently bound #AioContext
529  */
530 AioContext *bdrv_get_aio_context(BlockDriverState *bs);
531 
532 /**
533  * Transfer control to @co in the aio context of @bs
534  */
535 void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co);
536 
537 /**
538  * bdrv_set_aio_context:
539  *
540  * Changes the #AioContext used for fd handlers, timers, and BHs by this
541  * BlockDriverState and all its children.
542  *
543  * This function must be called with iothread lock held.
544  */
545 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context);
546 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
547 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
548 
549 void bdrv_io_plug(BlockDriverState *bs);
550 void bdrv_io_unplug(BlockDriverState *bs);
551 
552 /**
553  * bdrv_parent_drained_begin:
554  *
555  * Begin a quiesced section of all users of @bs. This is part of
556  * bdrv_drained_begin.
557  */
558 void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore);
559 
560 /**
561  * bdrv_parent_drained_end:
562  *
563  * End a quiesced section of all users of @bs. This is part of
564  * bdrv_drained_end.
565  */
566 void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore);
567 
568 /**
569  * bdrv_drained_begin:
570  *
571  * Begin a quiesced section for exclusive access to the BDS, by disabling
572  * external request sources including NBD server and device model. Note that
573  * this doesn't block timers or coroutines from submitting more requests, which
574  * means block_job_pause is still necessary.
575  *
576  * This function can be recursive.
577  */
578 void bdrv_drained_begin(BlockDriverState *bs);
579 
580 /**
581  * Like bdrv_drained_begin, but recursively begins a quiesced section for
582  * exclusive access to all child nodes as well.
583  */
584 void bdrv_subtree_drained_begin(BlockDriverState *bs);
585 
586 /**
587  * bdrv_drained_end:
588  *
589  * End a quiescent section started by bdrv_drained_begin().
590  */
591 void bdrv_drained_end(BlockDriverState *bs);
592 
593 /**
594  * End a quiescent section started by bdrv_subtree_drained_begin().
595  */
596 void bdrv_subtree_drained_end(BlockDriverState *bs);
597 
598 void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
599                     Error **errp);
600 void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
601 
602 bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
603                                      uint32_t granularity, Error **errp);
604 /**
605  *
606  * bdrv_register_buf/bdrv_unregister_buf:
607  *
608  * Register/unregister a buffer for I/O. For example, VFIO drivers are
609  * interested to know the memory areas that would later be used for I/O, so
610  * that they can prepare IOMMU mapping etc., to get better performance.
611  */
612 void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size);
613 void bdrv_unregister_buf(BlockDriverState *bs, void *host);
614 #endif
615