include/block/block-io.h

   1 /*
   2  * QEMU System Emulator block driver
   3  *
   4  * Copyright (c) 2003 Fabrice Bellard
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #ifndef BLOCK_IO_H
  25 #define BLOCK_IO_H
  26
  27 #include "block/aio-wait.h"
  28 #include "block/block-common.h"
  29 #include "qemu/coroutine.h"
  30 #include "qemu/iov.h"
  31
  32 /*
  33  * I/O API functions. These functions are thread-safe, and therefore
  34  * can run in any thread as long as the thread has called
  35  * aio_context_acquire/release().
  36  *
  37  * These functions can only call functions from I/O and Common categories,
  38  * but can be invoked by GS, "I/O or GS" and I/O APIs.
  39  *
  40  * All functions in this category must use the macro
  41  * IO_CODE();
  42  * to catch when they are accidentally called by the wrong API.
  43  */
  44
  45 int co_wrapper_mixed_bdrv_rdlock
  46 bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset, int64_t bytes,
  47                    BdrvRequestFlags flags);
  48
  49 int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
  50
  51 int co_wrapper_mixed_bdrv_rdlock
  52 bdrv_pread(BdrvChild *child, int64_t offset, int64_t bytes, void *buf,
  53            BdrvRequestFlags flags);
  54
  55 int co_wrapper_mixed_bdrv_rdlock
  56 bdrv_pwrite(BdrvChild *child, int64_t offset,int64_t bytes,
  57             const void *buf, BdrvRequestFlags flags);
  58
  59 int co_wrapper_mixed_bdrv_rdlock
  60 bdrv_pwrite_sync(BdrvChild *child, int64_t offset, int64_t bytes,
  61                  const void *buf, BdrvRequestFlags flags);
  62
  63 int coroutine_fn GRAPH_RDLOCK
  64 bdrv_co_pwrite_sync(BdrvChild *child, int64_t offset, int64_t bytes,
  65                     const void *buf, BdrvRequestFlags flags);
  66
  67 /*
  68  * Efficiently zero a region of the disk image.  Note that this is a regular
  69  * I/O request like read or write and should have a reasonable size.  This
  70  * function is not suitable for zeroing the entire image in a single request
  71  * because it may allocate memory for the entire region.
  72  */
  73 int coroutine_fn GRAPH_RDLOCK
  74 bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset, int64_t bytes,
  75                       BdrvRequestFlags flags);
  76
  77 int coroutine_fn GRAPH_RDLOCK
  78 bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact,
  79                  PreallocMode prealloc, BdrvRequestFlags flags, Error **errp);
  80
  81 int64_t coroutine_fn GRAPH_RDLOCK bdrv_co_nb_sectors(BlockDriverState *bs);
  82 int64_t coroutine_mixed_fn bdrv_nb_sectors(BlockDriverState *bs);
  83
  84 int64_t coroutine_fn GRAPH_RDLOCK bdrv_co_getlength(BlockDriverState *bs);
  85 int64_t co_wrapper_mixed_bdrv_rdlock bdrv_getlength(BlockDriverState *bs);
  86
  87 int64_t coroutine_fn GRAPH_RDLOCK
  88 bdrv_co_get_allocated_file_size(BlockDriverState *bs);
  89
  90 int64_t co_wrapper_bdrv_rdlock
  91 bdrv_get_allocated_file_size(BlockDriverState *bs);
  92
  93 BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
  94                                BlockDriverState *in_bs, Error **errp);
  95
  96 int coroutine_fn GRAPH_RDLOCK
  97 bdrv_co_delete_file(BlockDriverState *bs, Error **errp);
  98
  99 void coroutine_fn GRAPH_RDLOCK
 100 bdrv_co_delete_file_noerr(BlockDriverState *bs);
 101
 102
 103 /* async block I/O */
 104 void bdrv_aio_cancel_async(BlockAIOCB *acb);
 105
 106 /* sg packet commands */
 107 int coroutine_fn GRAPH_RDLOCK
 108 bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf);
 109
 110 /* Ensure contents are flushed to disk.  */
 111 int coroutine_fn GRAPH_RDLOCK bdrv_co_flush(BlockDriverState *bs);
 112
 113 int coroutine_fn GRAPH_RDLOCK bdrv_co_pdiscard(BdrvChild *child, int64_t offset,
 114                                                int64_t bytes);
 115
 116 /* Report zone information of zone block device. */
 117 int coroutine_fn GRAPH_RDLOCK bdrv_co_zone_report(BlockDriverState *bs,
 118                                                   int64_t offset,
 119                                                   unsigned int *nr_zones,
 120                                                   BlockZoneDescriptor *zones);
 121 int coroutine_fn GRAPH_RDLOCK bdrv_co_zone_mgmt(BlockDriverState *bs,
 122                                                 BlockZoneOp op,
 123                                                 int64_t offset, int64_t len);
 124 int coroutine_fn GRAPH_RDLOCK bdrv_co_zone_append(BlockDriverState *bs,
 125                                                   int64_t *offset,
 126                                                   QEMUIOVector *qiov,
 127                                                   BdrvRequestFlags flags);
 128
 129 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
 130
 131 int coroutine_fn GRAPH_RDLOCK
 132 bdrv_co_block_status(BlockDriverState *bs, int64_t offset, int64_t bytes,
 133                      int64_t *pnum, int64_t *map, BlockDriverState **file);
 134 int co_wrapper_mixed_bdrv_rdlock
 135 bdrv_block_status(BlockDriverState *bs, int64_t offset, int64_t bytes,
 136                   int64_t *pnum, int64_t *map, BlockDriverState **file);
 137
 138 int coroutine_fn GRAPH_RDLOCK
 139 bdrv_co_block_status_above(BlockDriverState *bs, BlockDriverState *base,
 140                            int64_t offset, int64_t bytes, int64_t *pnum,
 141                            int64_t *map, BlockDriverState **file);
 142 int co_wrapper_mixed_bdrv_rdlock
 143 bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
 144                         int64_t offset, int64_t bytes, int64_t *pnum,
 145                         int64_t *map, BlockDriverState **file);
 146
 147 int coroutine_fn GRAPH_RDLOCK
 148 bdrv_co_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
 149                      int64_t *pnum);
 150 int co_wrapper_mixed_bdrv_rdlock
 151 bdrv_is_allocated(BlockDriverState *bs, int64_t offset,
 152                   int64_t bytes, int64_t *pnum);
 153
 154 int coroutine_fn GRAPH_RDLOCK
 155 bdrv_co_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
 156                            bool include_base, int64_t offset, int64_t bytes,
 157                            int64_t *pnum);
 158 int co_wrapper_mixed_bdrv_rdlock
 159 bdrv_is_allocated_above(BlockDriverState *bs, BlockDriverState *base,
 160                         bool include_base, int64_t offset,
 161                         int64_t bytes, int64_t *pnum);
 162
 163 int coroutine_fn GRAPH_RDLOCK
 164 bdrv_co_is_zero_fast(BlockDriverState *bs, int64_t offset, int64_t bytes);
 165
 166 int GRAPH_RDLOCK
 167 bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg,
 168                           Error **errp);
 169
 170 bool bdrv_is_read_only(BlockDriverState *bs);
 171 bool bdrv_is_writable(BlockDriverState *bs);
 172 bool bdrv_is_sg(BlockDriverState *bs);
 173 int bdrv_get_flags(BlockDriverState *bs);
 174
 175 bool coroutine_fn GRAPH_RDLOCK bdrv_co_is_inserted(BlockDriverState *bs);
 176 bool co_wrapper_bdrv_rdlock bdrv_is_inserted(BlockDriverState *bs);
 177
 178 void coroutine_fn GRAPH_RDLOCK
 179 bdrv_co_lock_medium(BlockDriverState *bs, bool locked);
 180
 181 void coroutine_fn GRAPH_RDLOCK
 182 bdrv_co_eject(BlockDriverState *bs, bool eject_flag);
 183
 184 const char *bdrv_get_format_name(BlockDriverState *bs);
 185
 186 bool GRAPH_RDLOCK bdrv_supports_compressed_writes(BlockDriverState *bs);
 187 const char *bdrv_get_node_name(const BlockDriverState *bs);
 188
 189 const char * GRAPH_RDLOCK
 190 bdrv_get_device_name(const BlockDriverState *bs);
 191
 192 const char * GRAPH_RDLOCK
 193 bdrv_get_device_or_node_name(const BlockDriverState *bs);
 194
 195 int coroutine_fn GRAPH_RDLOCK
 196 bdrv_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
 197
 198 int co_wrapper_mixed_bdrv_rdlock
 199 bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
 200
 201 ImageInfoSpecific * GRAPH_RDLOCK
 202 bdrv_get_specific_info(BlockDriverState *bs, Error **errp);
 203
 204 BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs);
 205 void bdrv_round_to_subclusters(BlockDriverState *bs,
 206                                int64_t offset, int64_t bytes,
 207                                int64_t *cluster_offset,
 208                                int64_t *cluster_bytes);
 209
 210 void bdrv_get_backing_filename(BlockDriverState *bs,
 211                                char *filename, int filename_size);
 212
 213 int coroutine_fn GRAPH_RDLOCK
 214 bdrv_co_change_backing_file(BlockDriverState *bs, const char *backing_file,
 215                             const char *backing_fmt, bool warn);
 216
 217 int co_wrapper_bdrv_rdlock
 218 bdrv_change_backing_file(BlockDriverState *bs, const char *backing_file,
 219                          const char *backing_fmt, bool warn);
 220
 221 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
 222                       int64_t pos, int size);
 223
 224 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
 225                       int64_t pos, int size);
 226
 227 /*
 228  * Returns the alignment in bytes that is required so that no bounce buffer
 229  * is required throughout the stack
 230  */
 231 size_t bdrv_min_mem_align(BlockDriverState *bs);
 232 /* Returns optimal alignment in bytes for bounce buffer */
 233 size_t bdrv_opt_mem_align(BlockDriverState *bs);
 234 void *qemu_blockalign(BlockDriverState *bs, size_t size);
 235 void *qemu_blockalign0(BlockDriverState *bs, size_t size);
 236 void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
 237 void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
 238
 239 void bdrv_enable_copy_on_read(BlockDriverState *bs);
 240 void bdrv_disable_copy_on_read(BlockDriverState *bs);
 241
 242 void coroutine_fn GRAPH_RDLOCK
 243 bdrv_co_debug_event(BlockDriverState *bs, BlkdebugEvent event);
 244
 245 void co_wrapper_mixed_bdrv_rdlock
 246 bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
 247
 248 #define BLKDBG_CO_EVENT(child, evt) \
 249     do { \
 250         if (child) { \
 251             bdrv_co_debug_event(child->bs, evt); \
 252         } \
 253     } while (0)
 254
 255 #define BLKDBG_EVENT(child, evt) \
 256     do { \
 257         if (child) { \
 258             bdrv_debug_event(child->bs, evt); \
 259         } \
 260     } while (0)
 261
 262 /**
 263  * bdrv_get_aio_context:
 264  *
 265  * Returns: the currently bound #AioContext
 266  */
 267 AioContext *bdrv_get_aio_context(BlockDriverState *bs);
 268
 269 AioContext *bdrv_child_get_parent_aio_context(BdrvChild *c);
 270
 271 /**
 272  * Move the current coroutine to the AioContext of @bs and return the old
 273  * AioContext of the coroutine. Increase bs->in_flight so that draining @bs
 274  * will wait for the operation to proceed until the corresponding
 275  * bdrv_co_leave().
 276  *
 277  * Consequently, you can't call drain inside a bdrv_co_enter/leave() section as
 278  * this will deadlock.
 279  */
 280 AioContext *coroutine_fn bdrv_co_enter(BlockDriverState *bs);
 281
 282 /**
 283  * Ends a section started by bdrv_co_enter(). Move the current coroutine back
 284  * to old_ctx and decrease bs->in_flight again.
 285  */
 286 void coroutine_fn bdrv_co_leave(BlockDriverState *bs, AioContext *old_ctx);
 287
 288 AioContext *child_of_bds_get_parent_aio_context(BdrvChild *c);
 289
 290 bool coroutine_fn GRAPH_RDLOCK
 291 bdrv_co_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
 292                                    uint32_t granularity, Error **errp);
 293 bool co_wrapper_bdrv_rdlock
 294 bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
 295                                 uint32_t granularity, Error **errp);
 296
 297 /**
 298  *
 299  * bdrv_co_copy_range:
 300  *
 301  * Do offloaded copy between two children. If the operation is not implemented
 302  * by the driver, or if the backend storage doesn't support it, a negative
 303  * error code will be returned.
 304  *
 305  * Note: block layer doesn't emulate or fallback to a bounce buffer approach
 306  * because usually the caller shouldn't attempt offloaded copy any more (e.g.
 307  * calling copy_file_range(2)) after the first error, thus it should fall back
 308  * to a read+write path in the caller level.
 309  *
 310  * @src: Source child to copy data from
 311  * @src_offset: offset in @src image to read data
 312  * @dst: Destination child to copy data to
 313  * @dst_offset: offset in @dst image to write data
 314  * @bytes: number of bytes to copy
 315  * @flags: request flags. Supported flags:
 316  *         BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero
 317  *                               write on @dst as if bdrv_co_pwrite_zeroes is
 318  *                               called. Used to simplify caller code, or
 319  *                               during BlockDriver.bdrv_co_copy_range_from()
 320  *                               recursion.
 321  *         BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping
 322  *                                   requests currently in flight.
 323  *
 324  * Returns: 0 if succeeded; negative error code if failed.
 325  **/
 326 int coroutine_fn GRAPH_RDLOCK
 327 bdrv_co_copy_range(BdrvChild *src, int64_t src_offset,
 328                    BdrvChild *dst, int64_t dst_offset,
 329                    int64_t bytes, BdrvRequestFlags read_flags,
 330                    BdrvRequestFlags write_flags);
 331
 332 /*
 333  * "I/O or GS" API functions. These functions can run without
 334  * the BQL, but only in one specific iothread/main loop.
 335  *
 336  * More specifically, these functions use BDRV_POLL_WHILE(bs), which
 337  * requires the caller to be either in the main thread and hold
 338  * the BlockdriverState (bs) AioContext lock, or directly in the
 339  * home thread that runs the bs AioContext. Calling them from
 340  * another thread in another AioContext would cause deadlocks.
 341  *
 342  * Therefore, these functions are not proper I/O, because they
 343  * can't run in *any* iothreads, but only in a specific one.
 344  *
 345  * These functions can call any function from I/O, Common and this
 346  * categories, but must be invoked only by other "I/O or GS" and GS APIs.
 347  *
 348  * All functions in this category must use the macro
 349  * IO_OR_GS_CODE();
 350  * to catch when they are accidentally called by the wrong API.
 351  */
 352
 353 #define BDRV_POLL_WHILE(bs, cond) ({                       \
 354     BlockDriverState *bs_ = (bs);                          \
 355     IO_OR_GS_CODE();                                       \
 356     AIO_WAIT_WHILE(bdrv_get_aio_context(bs_),              \
 357                    cond); })
 358
 359 void bdrv_drain(BlockDriverState *bs);
 360
 361 int co_wrapper_mixed_bdrv_rdlock
 362 bdrv_truncate(BdrvChild *child, int64_t offset, bool exact,
 363               PreallocMode prealloc, BdrvRequestFlags flags, Error **errp);
 364
 365 int co_wrapper_mixed_bdrv_rdlock
 366 bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
 367
 368 /* Invalidate any cached metadata used by image formats */
 369 int co_wrapper_mixed_bdrv_rdlock
 370 bdrv_invalidate_cache(BlockDriverState *bs, Error **errp);
 371
 372 int co_wrapper_mixed_bdrv_rdlock bdrv_flush(BlockDriverState *bs);
 373
 374 int co_wrapper_mixed_bdrv_rdlock
 375 bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
 376
 377 int co_wrapper_mixed_bdrv_rdlock
 378 bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 379
 380 int co_wrapper_mixed_bdrv_rdlock
 381 bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 382
 383 /**
 384  * bdrv_parent_drained_begin_single:
 385  *
 386  * Begin a quiesced section for the parent of @c.
 387  */
 388 void GRAPH_RDLOCK bdrv_parent_drained_begin_single(BdrvChild *c);
 389
 390 /**
 391  * bdrv_parent_drained_poll_single:
 392  *
 393  * Returns true if there is any pending activity to cease before @c can be
 394  * called quiesced, false otherwise.
 395  */
 396 bool GRAPH_RDLOCK bdrv_parent_drained_poll_single(BdrvChild *c);
 397
 398 /**
 399  * bdrv_parent_drained_end_single:
 400  *
 401  * End a quiesced section for the parent of @c.
 402  */
 403 void GRAPH_RDLOCK bdrv_parent_drained_end_single(BdrvChild *c);
 404
 405 /**
 406  * bdrv_drain_poll:
 407  *
 408  * Poll for pending requests in @bs and its parents (except for @ignore_parent).
 409  *
 410  * If @ignore_bds_parents is true, parents that are BlockDriverStates must
 411  * ignore the drain request because they will be drained separately (used for
 412  * drain_all).
 413  *
 414  * This is part of bdrv_drained_begin.
 415  */
 416 bool GRAPH_RDLOCK
 417 bdrv_drain_poll(BlockDriverState *bs, BdrvChild *ignore_parent,
 418                 bool ignore_bds_parents);
 419
 420 /**
 421  * bdrv_drained_begin:
 422  *
 423  * Begin a quiesced section for exclusive access to the BDS, by disabling
 424  * external request sources including NBD server, block jobs, and device model.
 425  *
 426  * This function can only be invoked by the main loop or a coroutine
 427  * (regardless of the AioContext where it is running).
 428  * If the coroutine is running in an Iothread AioContext, this function will
 429  * just schedule a BH to run in the main loop.
 430  * However, it cannot be directly called by an Iothread.
 431  *
 432  * This function can be recursive.
 433  */
 434 void bdrv_drained_begin(BlockDriverState *bs);
 435
 436 /**
 437  * bdrv_do_drained_begin_quiesce:
 438  *
 439  * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already
 440  * running requests to complete.
 441  */
 442 void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent);
 443
 444 /**
 445  * bdrv_drained_end:
 446  *
 447  * End a quiescent section started by bdrv_drained_begin().
 448  *
 449  * This function can only be invoked by the main loop or a coroutine
 450  * (regardless of the AioContext where it is running).
 451  * If the coroutine is running in an Iothread AioContext, this function will
 452  * just schedule a BH to run in the main loop.
 453  * However, it cannot be directly called by an Iothread.
 454  */
 455 void bdrv_drained_end(BlockDriverState *bs);
 456
 457 #endif /* BLOCK_IO_H */