xref: /openbmc/qemu/include/block/block.h (revision 0ec7b3e7)
1 #ifndef BLOCK_H
2 #define BLOCK_H
3 
4 #include "block/aio.h"
5 #include "qemu/iov.h"
6 #include "qemu/option.h"
7 #include "qemu/coroutine.h"
8 #include "block/accounting.h"
9 #include "block/dirty-bitmap.h"
10 #include "block/blockjob.h"
11 #include "qapi/qmp/qobject.h"
12 #include "qapi-types.h"
13 #include "qemu/hbitmap.h"
14 
15 /* block.c */
16 typedef struct BlockDriver BlockDriver;
17 typedef struct BdrvChild BdrvChild;
18 typedef struct BdrvChildRole BdrvChildRole;
19 
20 typedef struct BlockDriverInfo {
21     /* in bytes, 0 if irrelevant */
22     int cluster_size;
23     /* offset at which the VM state can be saved (0 if not possible) */
24     int64_t vm_state_offset;
25     bool is_dirty;
26     /*
27      * True if unallocated blocks read back as zeroes. This is equivalent
28      * to the LBPRZ flag in the SCSI logical block provisioning page.
29      */
30     bool unallocated_blocks_are_zero;
31     /*
32      * True if the driver can optimize writing zeroes by unmapping
33      * sectors. This is equivalent to the BLKDISCARDZEROES ioctl in Linux
34      * with the difference that in qemu a discard is allowed to silently
35      * fail. Therefore we have to use bdrv_pwrite_zeroes with the
36      * BDRV_REQ_MAY_UNMAP flag for an optimized zero write with unmapping.
37      * After this call the driver has to guarantee that the contents read
38      * back as zero. It is additionally required that the block device is
39      * opened with BDRV_O_UNMAP flag for this to work.
40      */
41     bool can_write_zeroes_with_unmap;
42     /*
43      * True if this block driver only supports compressed writes
44      */
45     bool needs_compressed_writes;
46 } BlockDriverInfo;
47 
48 typedef struct BlockFragInfo {
49     uint64_t allocated_clusters;
50     uint64_t total_clusters;
51     uint64_t fragmented_clusters;
52     uint64_t compressed_clusters;
53 } BlockFragInfo;
54 
55 typedef enum {
56     BDRV_REQ_COPY_ON_READ       = 0x1,
57     BDRV_REQ_ZERO_WRITE         = 0x2,
58     /* The BDRV_REQ_MAY_UNMAP flag is used to indicate that the block driver
59      * is allowed to optimize a write zeroes request by unmapping (discarding)
60      * blocks if it is guaranteed that the result will read back as
61      * zeroes. The flag is only passed to the driver if the block device is
62      * opened with BDRV_O_UNMAP.
63      */
64     BDRV_REQ_MAY_UNMAP          = 0x4,
65     BDRV_REQ_NO_SERIALISING     = 0x8,
66     BDRV_REQ_FUA                = 0x10,
67     BDRV_REQ_WRITE_COMPRESSED   = 0x20,
68 
69     /* Mask of valid flags */
70     BDRV_REQ_MASK               = 0x3f,
71 } BdrvRequestFlags;
72 
73 typedef struct BlockSizes {
74     uint32_t phys;
75     uint32_t log;
76 } BlockSizes;
77 
78 typedef struct HDGeometry {
79     uint32_t heads;
80     uint32_t sectors;
81     uint32_t cylinders;
82 } HDGeometry;
83 
84 #define BDRV_O_RDWR        0x0002
85 #define BDRV_O_SNAPSHOT    0x0008 /* open the file read only and save writes in a snapshot */
86 #define BDRV_O_TEMPORARY   0x0010 /* delete the file after use */
87 #define BDRV_O_NOCACHE     0x0020 /* do not use the host page cache */
88 #define BDRV_O_NATIVE_AIO  0x0080 /* use native AIO instead of the thread pool */
89 #define BDRV_O_NO_BACKING  0x0100 /* don't open the backing file */
90 #define BDRV_O_NO_FLUSH    0x0200 /* disable flushing on this disk */
91 #define BDRV_O_COPY_ON_READ 0x0400 /* copy read backing sectors into image */
92 #define BDRV_O_INACTIVE    0x0800  /* consistency hint for migration handoff */
93 #define BDRV_O_CHECK       0x1000  /* open solely for consistency check */
94 #define BDRV_O_ALLOW_RDWR  0x2000  /* allow reopen to change from r/o to r/w */
95 #define BDRV_O_UNMAP       0x4000  /* execute guest UNMAP/TRIM operations */
96 #define BDRV_O_PROTOCOL    0x8000  /* if no block driver is explicitly given:
97                                       select an appropriate protocol driver,
98                                       ignoring the format layer */
99 #define BDRV_O_NO_IO       0x10000 /* don't initialize for I/O */
100 
101 #define BDRV_O_CACHE_MASK  (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH)
102 
103 
104 /* Option names of options parsed by the block layer */
105 
106 #define BDRV_OPT_CACHE_WB       "cache.writeback"
107 #define BDRV_OPT_CACHE_DIRECT   "cache.direct"
108 #define BDRV_OPT_CACHE_NO_FLUSH "cache.no-flush"
109 #define BDRV_OPT_READ_ONLY      "read-only"
110 #define BDRV_OPT_DISCARD        "discard"
111 
112 
113 #define BDRV_SECTOR_BITS   9
114 #define BDRV_SECTOR_SIZE   (1ULL << BDRV_SECTOR_BITS)
115 #define BDRV_SECTOR_MASK   ~(BDRV_SECTOR_SIZE - 1)
116 
117 #define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \
118                                      INT_MAX >> BDRV_SECTOR_BITS)
119 #define BDRV_REQUEST_MAX_BYTES (BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS)
120 
121 /*
122  * Allocation status flags
123  * BDRV_BLOCK_DATA: data is read from a file returned by bdrv_get_block_status.
124  * BDRV_BLOCK_ZERO: sectors read as zero
125  * BDRV_BLOCK_OFFSET_VALID: sector stored as raw data in a file returned by
126  *                          bdrv_get_block_status.
127  * BDRV_BLOCK_ALLOCATED: the content of the block is determined by this
128  *                       layer (as opposed to the backing file)
129  * BDRV_BLOCK_RAW: used internally to indicate that the request
130  *                 was answered by the raw driver and that one
131  *                 should look in bs->file directly.
132  *
133  * If BDRV_BLOCK_OFFSET_VALID is set, bits 9-62 represent the offset in
134  * bs->file where sector data can be read from as raw data.
135  *
136  * DATA == 0 && ZERO == 0 means that data is read from backing_hd if present.
137  *
138  * DATA ZERO OFFSET_VALID
139  *  t    t        t       sectors read as zero, bs->file is zero at offset
140  *  t    f        t       sectors read as valid from bs->file at offset
141  *  f    t        t       sectors preallocated, read as zero, bs->file not
142  *                        necessarily zero at offset
143  *  f    f        t       sectors preallocated but read from backing_hd,
144  *                        bs->file contains garbage at offset
145  *  t    t        f       sectors preallocated, read as zero, unknown offset
146  *  t    f        f       sectors read from unknown file or offset
147  *  f    t        f       not allocated or unknown offset, read as zero
148  *  f    f        f       not allocated or unknown offset, read from backing_hd
149  */
150 #define BDRV_BLOCK_DATA         0x01
151 #define BDRV_BLOCK_ZERO         0x02
152 #define BDRV_BLOCK_OFFSET_VALID 0x04
153 #define BDRV_BLOCK_RAW          0x08
154 #define BDRV_BLOCK_ALLOCATED    0x10
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     QDict *options;
163     QDict *explicit_options;
164     void *opaque;
165 } BDRVReopenState;
166 
167 /*
168  * Block operation types
169  */
170 typedef enum BlockOpType {
171     BLOCK_OP_TYPE_BACKUP_SOURCE,
172     BLOCK_OP_TYPE_BACKUP_TARGET,
173     BLOCK_OP_TYPE_CHANGE,
174     BLOCK_OP_TYPE_COMMIT_SOURCE,
175     BLOCK_OP_TYPE_COMMIT_TARGET,
176     BLOCK_OP_TYPE_DATAPLANE,
177     BLOCK_OP_TYPE_DRIVE_DEL,
178     BLOCK_OP_TYPE_EJECT,
179     BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
180     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT,
181     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
182     BLOCK_OP_TYPE_MIRROR_SOURCE,
183     BLOCK_OP_TYPE_MIRROR_TARGET,
184     BLOCK_OP_TYPE_RESIZE,
185     BLOCK_OP_TYPE_STREAM,
186     BLOCK_OP_TYPE_REPLACE,
187     BLOCK_OP_TYPE_MAX,
188 } BlockOpType;
189 
190 /* disk I/O throttling */
191 void bdrv_init(void);
192 void bdrv_init_with_whitelist(void);
193 bool bdrv_uses_whitelist(void);
194 BlockDriver *bdrv_find_protocol(const char *filename,
195                                 bool allow_protocol_prefix,
196                                 Error **errp);
197 BlockDriver *bdrv_find_format(const char *format_name);
198 int bdrv_create(BlockDriver *drv, const char* filename,
199                 QemuOpts *opts, Error **errp);
200 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp);
201 BlockDriverState *bdrv_new(void);
202 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top);
203 void bdrv_replace_in_backing_chain(BlockDriverState *old,
204                                    BlockDriverState *new);
205 
206 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough);
207 int bdrv_parse_discard_flags(const char *mode, int *flags);
208 BdrvChild *bdrv_open_child(const char *filename,
209                            QDict *options, const char *bdref_key,
210                            BlockDriverState* parent,
211                            const BdrvChildRole *child_role,
212                            bool allow_none, Error **errp);
213 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd);
214 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
215                            const char *bdref_key, Error **errp);
216 BlockDriverState *bdrv_open(const char *filename, const char *reference,
217                             QDict *options, int flags, Error **errp);
218 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
219                                     BlockDriverState *bs,
220                                     QDict *options, int flags);
221 int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **errp);
222 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp);
223 int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
224                         BlockReopenQueue *queue, Error **errp);
225 void bdrv_reopen_commit(BDRVReopenState *reopen_state);
226 void bdrv_reopen_abort(BDRVReopenState *reopen_state);
227 int bdrv_read(BdrvChild *child, int64_t sector_num,
228               uint8_t *buf, int nb_sectors);
229 int bdrv_write(BdrvChild *child, int64_t sector_num,
230                const uint8_t *buf, int nb_sectors);
231 int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
232                        int count, BdrvRequestFlags flags);
233 int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
234 int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes);
235 int bdrv_preadv(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
236 int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes);
237 int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
238 int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
239                      const void *buf, int count);
240 int coroutine_fn bdrv_co_readv(BdrvChild *child, int64_t sector_num,
241                                int nb_sectors, QEMUIOVector *qiov);
242 int coroutine_fn bdrv_co_writev(BdrvChild *child, int64_t sector_num,
243                                int nb_sectors, QEMUIOVector *qiov);
244 /*
245  * Efficiently zero a region of the disk image.  Note that this is a regular
246  * I/O request like read or write and should have a reasonable size.  This
247  * function is not suitable for zeroing the entire image in a single request
248  * because it may allocate memory for the entire region.
249  */
250 int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
251                                        int count, BdrvRequestFlags flags);
252 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
253     const char *backing_file);
254 int bdrv_get_backing_file_depth(BlockDriverState *bs);
255 void bdrv_refresh_filename(BlockDriverState *bs);
256 int bdrv_truncate(BlockDriverState *bs, int64_t offset);
257 int64_t bdrv_nb_sectors(BlockDriverState *bs);
258 int64_t bdrv_getlength(BlockDriverState *bs);
259 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
260 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
261 void bdrv_refresh_limits(BlockDriverState *bs, Error **errp);
262 int bdrv_commit(BlockDriverState *bs);
263 int bdrv_change_backing_file(BlockDriverState *bs,
264     const char *backing_file, const char *backing_fmt);
265 void bdrv_register(BlockDriver *bdrv);
266 int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
267                            BlockDriverState *base,
268                            const char *backing_file_str);
269 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
270                                     BlockDriverState *bs);
271 BlockDriverState *bdrv_find_base(BlockDriverState *bs);
272 
273 
274 typedef struct BdrvCheckResult {
275     int corruptions;
276     int leaks;
277     int check_errors;
278     int corruptions_fixed;
279     int leaks_fixed;
280     int64_t image_end_offset;
281     BlockFragInfo bfi;
282 } BdrvCheckResult;
283 
284 typedef enum {
285     BDRV_FIX_LEAKS    = 1,
286     BDRV_FIX_ERRORS   = 2,
287 } BdrvCheckMode;
288 
289 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
290 
291 /* The units of offset and total_work_size may be chosen arbitrarily by the
292  * block driver; total_work_size may change during the course of the amendment
293  * operation */
294 typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
295                                       int64_t total_work_size, void *opaque);
296 int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
297                        BlockDriverAmendStatusCB *status_cb, void *cb_opaque);
298 
299 /* external snapshots */
300 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
301                                       BlockDriverState *candidate);
302 bool bdrv_is_first_non_filter(BlockDriverState *candidate);
303 
304 /* check if a named node can be replaced when doing drive-mirror */
305 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
306                                         const char *node_name, Error **errp);
307 
308 /* async block I/O */
309 BlockAIOCB *bdrv_aio_readv(BdrvChild *child, int64_t sector_num,
310                            QEMUIOVector *iov, int nb_sectors,
311                            BlockCompletionFunc *cb, void *opaque);
312 BlockAIOCB *bdrv_aio_writev(BdrvChild *child, int64_t sector_num,
313                             QEMUIOVector *iov, int nb_sectors,
314                             BlockCompletionFunc *cb, void *opaque);
315 BlockAIOCB *bdrv_aio_flush(BlockDriverState *bs,
316                            BlockCompletionFunc *cb, void *opaque);
317 void bdrv_aio_cancel(BlockAIOCB *acb);
318 void bdrv_aio_cancel_async(BlockAIOCB *acb);
319 
320 /* sg packet commands */
321 int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf);
322 
323 /* Invalidate any cached metadata used by image formats */
324 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp);
325 void bdrv_invalidate_cache_all(Error **errp);
326 int bdrv_inactivate_all(void);
327 
328 /* Ensure contents are flushed to disk.  */
329 int bdrv_flush(BlockDriverState *bs);
330 int coroutine_fn bdrv_co_flush(BlockDriverState *bs);
331 int bdrv_flush_all(void);
332 void bdrv_close_all(void);
333 void bdrv_drain(BlockDriverState *bs);
334 void coroutine_fn bdrv_co_drain(BlockDriverState *bs);
335 void bdrv_drain_all_begin(void);
336 void bdrv_drain_all_end(void);
337 void bdrv_drain_all(void);
338 
339 #define BDRV_POLL_WHILE(bs, cond) ({                       \
340     bool waited_ = false;                                  \
341     BlockDriverState *bs_ = (bs);                          \
342     AioContext *ctx_ = bdrv_get_aio_context(bs_);          \
343     if (aio_context_in_iothread(ctx_)) {                   \
344         while ((cond)) {                                   \
345             aio_poll(ctx_, true);                          \
346             waited_ = true;                                \
347         }                                                  \
348     } else {                                               \
349         assert(qemu_get_current_aio_context() ==           \
350                qemu_get_aio_context());                    \
351         /* Ask bdrv_dec_in_flight to wake up the main      \
352          * QEMU AioContext.  Extra I/O threads never take  \
353          * other I/O threads' AioContexts (see for example \
354          * block_job_defer_to_main_loop for how to do it). \
355          */                                                \
356         assert(!bs_->wakeup);                              \
357         bs_->wakeup = true;                                \
358         while ((cond)) {                                   \
359             aio_context_release(ctx_);                     \
360             aio_poll(qemu_get_aio_context(), true);        \
361             aio_context_acquire(ctx_);                     \
362             waited_ = true;                                \
363         }                                                  \
364         bs_->wakeup = false;                               \
365     }                                                      \
366     waited_; })
367 
368 int bdrv_pdiscard(BlockDriverState *bs, int64_t offset, int count);
369 int bdrv_co_pdiscard(BlockDriverState *bs, int64_t offset, int count);
370 int bdrv_has_zero_init_1(BlockDriverState *bs);
371 int bdrv_has_zero_init(BlockDriverState *bs);
372 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs);
373 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
374 int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num,
375                               int nb_sectors, int *pnum,
376                               BlockDriverState **file);
377 int64_t bdrv_get_block_status_above(BlockDriverState *bs,
378                                     BlockDriverState *base,
379                                     int64_t sector_num,
380                                     int nb_sectors, int *pnum,
381                                     BlockDriverState **file);
382 int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
383                       int *pnum);
384 int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
385                             int64_t sector_num, int nb_sectors, int *pnum);
386 
387 bool bdrv_is_read_only(BlockDriverState *bs);
388 bool bdrv_is_sg(BlockDriverState *bs);
389 bool bdrv_is_inserted(BlockDriverState *bs);
390 int bdrv_media_changed(BlockDriverState *bs);
391 void bdrv_lock_medium(BlockDriverState *bs, bool locked);
392 void bdrv_eject(BlockDriverState *bs, bool eject_flag);
393 const char *bdrv_get_format_name(BlockDriverState *bs);
394 BlockDriverState *bdrv_find_node(const char *node_name);
395 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp);
396 BlockDriverState *bdrv_lookup_bs(const char *device,
397                                  const char *node_name,
398                                  Error **errp);
399 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
400 BlockDriverState *bdrv_next_node(BlockDriverState *bs);
401 
402 typedef struct BdrvNextIterator {
403     enum {
404         BDRV_NEXT_BACKEND_ROOTS,
405         BDRV_NEXT_MONITOR_OWNED,
406     } phase;
407     BlockBackend *blk;
408     BlockDriverState *bs;
409 } BdrvNextIterator;
410 
411 BlockDriverState *bdrv_first(BdrvNextIterator *it);
412 BlockDriverState *bdrv_next(BdrvNextIterator *it);
413 
414 BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs);
415 bool bdrv_is_encrypted(BlockDriverState *bs);
416 bool bdrv_key_required(BlockDriverState *bs);
417 int bdrv_set_key(BlockDriverState *bs, const char *key);
418 void bdrv_add_key(BlockDriverState *bs, const char *key, Error **errp);
419 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
420                          void *opaque);
421 const char *bdrv_get_node_name(const BlockDriverState *bs);
422 const char *bdrv_get_device_name(const BlockDriverState *bs);
423 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
424 int bdrv_get_flags(BlockDriverState *bs);
425 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
426 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs);
427 void bdrv_round_sectors_to_clusters(BlockDriverState *bs,
428                                     int64_t sector_num, int nb_sectors,
429                                     int64_t *cluster_sector_num,
430                                     int *cluster_nb_sectors);
431 void bdrv_round_to_clusters(BlockDriverState *bs,
432                             int64_t offset, unsigned int bytes,
433                             int64_t *cluster_offset,
434                             unsigned int *cluster_bytes);
435 
436 const char *bdrv_get_encrypted_filename(BlockDriverState *bs);
437 void bdrv_get_backing_filename(BlockDriverState *bs,
438                                char *filename, int filename_size);
439 void bdrv_get_full_backing_filename(BlockDriverState *bs,
440                                     char *dest, size_t sz, Error **errp);
441 void bdrv_get_full_backing_filename_from_filename(const char *backed,
442                                                   const char *backing,
443                                                   char *dest, size_t sz,
444                                                   Error **errp);
445 
446 int path_has_protocol(const char *path);
447 int path_is_absolute(const char *path);
448 void path_combine(char *dest, int dest_size,
449                   const char *base_path,
450                   const char *filename);
451 
452 int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
453 int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
454 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
455                       int64_t pos, int size);
456 
457 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
458                       int64_t pos, int size);
459 
460 void bdrv_img_create(const char *filename, const char *fmt,
461                      const char *base_filename, const char *base_fmt,
462                      char *options, uint64_t img_size, int flags,
463                      Error **errp, bool quiet);
464 
465 /* Returns the alignment in bytes that is required so that no bounce buffer
466  * is required throughout the stack */
467 size_t bdrv_min_mem_align(BlockDriverState *bs);
468 /* Returns optimal alignment in bytes for bounce buffer */
469 size_t bdrv_opt_mem_align(BlockDriverState *bs);
470 void *qemu_blockalign(BlockDriverState *bs, size_t size);
471 void *qemu_blockalign0(BlockDriverState *bs, size_t size);
472 void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
473 void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
474 bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);
475 
476 void bdrv_enable_copy_on_read(BlockDriverState *bs);
477 void bdrv_disable_copy_on_read(BlockDriverState *bs);
478 
479 void bdrv_ref(BlockDriverState *bs);
480 void bdrv_unref(BlockDriverState *bs);
481 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child);
482 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
483                              BlockDriverState *child_bs,
484                              const char *child_name,
485                              const BdrvChildRole *child_role);
486 
487 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
488 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);
489 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason);
490 void bdrv_op_block_all(BlockDriverState *bs, Error *reason);
491 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason);
492 bool bdrv_op_blocker_is_empty(BlockDriverState *bs);
493 
494 #define BLKDBG_EVENT(child, evt) \
495     do { \
496         if (child) { \
497             bdrv_debug_event(child->bs, evt); \
498         } \
499     } while (0)
500 
501 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
502 
503 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
504                            const char *tag);
505 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag);
506 int bdrv_debug_resume(BlockDriverState *bs, const char *tag);
507 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag);
508 
509 /**
510  * bdrv_get_aio_context:
511  *
512  * Returns: the currently bound #AioContext
513  */
514 AioContext *bdrv_get_aio_context(BlockDriverState *bs);
515 
516 /**
517  * bdrv_set_aio_context:
518  *
519  * Changes the #AioContext used for fd handlers, timers, and BHs by this
520  * BlockDriverState and all its children.
521  *
522  * This function must be called with iothread lock held.
523  */
524 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context);
525 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
526 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
527 
528 void bdrv_io_plug(BlockDriverState *bs);
529 void bdrv_io_unplug(BlockDriverState *bs);
530 
531 /**
532  * bdrv_drained_begin:
533  *
534  * Begin a quiesced section for exclusive access to the BDS, by disabling
535  * external request sources including NBD server and device model. Note that
536  * this doesn't block timers or coroutines from submitting more requests, which
537  * means block_job_pause is still necessary.
538  *
539  * This function can be recursive.
540  */
541 void bdrv_drained_begin(BlockDriverState *bs);
542 
543 /**
544  * bdrv_drained_end:
545  *
546  * End a quiescent section started by bdrv_drained_begin().
547  */
548 void bdrv_drained_end(BlockDriverState *bs);
549 
550 void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
551                     Error **errp);
552 void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
553 
554 #endif
555