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 */ 458