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 bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg, 167 Error **errp); 168 bool bdrv_is_read_only(BlockDriverState *bs); 169 bool bdrv_is_writable(BlockDriverState *bs); 170 bool bdrv_is_sg(BlockDriverState *bs); 171 int bdrv_get_flags(BlockDriverState *bs); 172 173 bool coroutine_fn GRAPH_RDLOCK bdrv_co_is_inserted(BlockDriverState *bs); 174 bool co_wrapper_bdrv_rdlock bdrv_is_inserted(BlockDriverState *bs); 175 176 void coroutine_fn GRAPH_RDLOCK 177 bdrv_co_lock_medium(BlockDriverState *bs, bool locked); 178 179 void coroutine_fn GRAPH_RDLOCK 180 bdrv_co_eject(BlockDriverState *bs, bool eject_flag); 181 182 const char *bdrv_get_format_name(BlockDriverState *bs); 183 184 bool bdrv_supports_compressed_writes(BlockDriverState *bs); 185 const char *bdrv_get_node_name(const BlockDriverState *bs); 186 187 const char * GRAPH_RDLOCK 188 bdrv_get_device_name(const BlockDriverState *bs); 189 190 const char * GRAPH_RDLOCK 191 bdrv_get_device_or_node_name(const BlockDriverState *bs); 192 193 int coroutine_fn GRAPH_RDLOCK 194 bdrv_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi); 195 196 int co_wrapper_mixed_bdrv_rdlock 197 bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi); 198 199 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs, 200 Error **errp); 201 BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs); 202 void bdrv_round_to_subclusters(BlockDriverState *bs, 203 int64_t offset, int64_t bytes, 204 int64_t *cluster_offset, 205 int64_t *cluster_bytes); 206 207 void bdrv_get_backing_filename(BlockDriverState *bs, 208 char *filename, int filename_size); 209 210 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf, 211 int64_t pos, int size); 212 213 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf, 214 int64_t pos, int size); 215 216 /* 217 * Returns the alignment in bytes that is required so that no bounce buffer 218 * is required throughout the stack 219 */ 220 size_t bdrv_min_mem_align(BlockDriverState *bs); 221 /* Returns optimal alignment in bytes for bounce buffer */ 222 size_t bdrv_opt_mem_align(BlockDriverState *bs); 223 void *qemu_blockalign(BlockDriverState *bs, size_t size); 224 void *qemu_blockalign0(BlockDriverState *bs, size_t size); 225 void *qemu_try_blockalign(BlockDriverState *bs, size_t size); 226 void *qemu_try_blockalign0(BlockDriverState *bs, size_t size); 227 228 void bdrv_enable_copy_on_read(BlockDriverState *bs); 229 void bdrv_disable_copy_on_read(BlockDriverState *bs); 230 231 void coroutine_fn GRAPH_RDLOCK 232 bdrv_co_debug_event(BlockDriverState *bs, BlkdebugEvent event); 233 234 void co_wrapper_mixed_bdrv_rdlock 235 bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event); 236 237 #define BLKDBG_CO_EVENT(child, evt) \ 238 do { \ 239 if (child) { \ 240 bdrv_co_debug_event(child->bs, evt); \ 241 } \ 242 } while (0) 243 244 #define BLKDBG_EVENT(child, evt) \ 245 do { \ 246 if (child) { \ 247 bdrv_debug_event(child->bs, evt); \ 248 } \ 249 } while (0) 250 251 /** 252 * bdrv_get_aio_context: 253 * 254 * Returns: the currently bound #AioContext 255 */ 256 AioContext *bdrv_get_aio_context(BlockDriverState *bs); 257 258 AioContext *bdrv_child_get_parent_aio_context(BdrvChild *c); 259 260 /** 261 * Move the current coroutine to the AioContext of @bs and return the old 262 * AioContext of the coroutine. Increase bs->in_flight so that draining @bs 263 * will wait for the operation to proceed until the corresponding 264 * bdrv_co_leave(). 265 * 266 * Consequently, you can't call drain inside a bdrv_co_enter/leave() section as 267 * this will deadlock. 268 */ 269 AioContext *coroutine_fn bdrv_co_enter(BlockDriverState *bs); 270 271 /** 272 * Ends a section started by bdrv_co_enter(). Move the current coroutine back 273 * to old_ctx and decrease bs->in_flight again. 274 */ 275 void coroutine_fn bdrv_co_leave(BlockDriverState *bs, AioContext *old_ctx); 276 277 AioContext *child_of_bds_get_parent_aio_context(BdrvChild *c); 278 279 bool coroutine_fn GRAPH_RDLOCK 280 bdrv_co_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name, 281 uint32_t granularity, Error **errp); 282 bool co_wrapper_bdrv_rdlock 283 bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name, 284 uint32_t granularity, Error **errp); 285 286 /** 287 * 288 * bdrv_co_copy_range: 289 * 290 * Do offloaded copy between two children. If the operation is not implemented 291 * by the driver, or if the backend storage doesn't support it, a negative 292 * error code will be returned. 293 * 294 * Note: block layer doesn't emulate or fallback to a bounce buffer approach 295 * because usually the caller shouldn't attempt offloaded copy any more (e.g. 296 * calling copy_file_range(2)) after the first error, thus it should fall back 297 * to a read+write path in the caller level. 298 * 299 * @src: Source child to copy data from 300 * @src_offset: offset in @src image to read data 301 * @dst: Destination child to copy data to 302 * @dst_offset: offset in @dst image to write data 303 * @bytes: number of bytes to copy 304 * @flags: request flags. Supported flags: 305 * BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero 306 * write on @dst as if bdrv_co_pwrite_zeroes is 307 * called. Used to simplify caller code, or 308 * during BlockDriver.bdrv_co_copy_range_from() 309 * recursion. 310 * BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping 311 * requests currently in flight. 312 * 313 * Returns: 0 if succeeded; negative error code if failed. 314 **/ 315 int coroutine_fn GRAPH_RDLOCK 316 bdrv_co_copy_range(BdrvChild *src, int64_t src_offset, 317 BdrvChild *dst, int64_t dst_offset, 318 int64_t bytes, BdrvRequestFlags read_flags, 319 BdrvRequestFlags write_flags); 320 321 /* 322 * "I/O or GS" API functions. These functions can run without 323 * the BQL, but only in one specific iothread/main loop. 324 * 325 * More specifically, these functions use BDRV_POLL_WHILE(bs), which 326 * requires the caller to be either in the main thread and hold 327 * the BlockdriverState (bs) AioContext lock, or directly in the 328 * home thread that runs the bs AioContext. Calling them from 329 * another thread in another AioContext would cause deadlocks. 330 * 331 * Therefore, these functions are not proper I/O, because they 332 * can't run in *any* iothreads, but only in a specific one. 333 * 334 * These functions can call any function from I/O, Common and this 335 * categories, but must be invoked only by other "I/O or GS" and GS APIs. 336 * 337 * All functions in this category must use the macro 338 * IO_OR_GS_CODE(); 339 * to catch when they are accidentally called by the wrong API. 340 */ 341 342 #define BDRV_POLL_WHILE(bs, cond) ({ \ 343 BlockDriverState *bs_ = (bs); \ 344 IO_OR_GS_CODE(); \ 345 AIO_WAIT_WHILE(bdrv_get_aio_context(bs_), \ 346 cond); }) 347 348 void bdrv_drain(BlockDriverState *bs); 349 350 int co_wrapper_mixed_bdrv_rdlock 351 bdrv_truncate(BdrvChild *child, int64_t offset, bool exact, 352 PreallocMode prealloc, BdrvRequestFlags flags, Error **errp); 353 354 int co_wrapper_mixed_bdrv_rdlock 355 bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix); 356 357 /* Invalidate any cached metadata used by image formats */ 358 int co_wrapper_mixed_bdrv_rdlock 359 bdrv_invalidate_cache(BlockDriverState *bs, Error **errp); 360 361 int co_wrapper_mixed_bdrv_rdlock bdrv_flush(BlockDriverState *bs); 362 363 int co_wrapper_mixed_bdrv_rdlock 364 bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes); 365 366 int co_wrapper_mixed_bdrv_rdlock 367 bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); 368 369 int co_wrapper_mixed_bdrv_rdlock 370 bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); 371 372 /** 373 * bdrv_parent_drained_begin_single: 374 * 375 * Begin a quiesced section for the parent of @c. 376 */ 377 void GRAPH_RDLOCK bdrv_parent_drained_begin_single(BdrvChild *c); 378 379 /** 380 * bdrv_parent_drained_poll_single: 381 * 382 * Returns true if there is any pending activity to cease before @c can be 383 * called quiesced, false otherwise. 384 */ 385 bool GRAPH_RDLOCK bdrv_parent_drained_poll_single(BdrvChild *c); 386 387 /** 388 * bdrv_parent_drained_end_single: 389 * 390 * End a quiesced section for the parent of @c. 391 */ 392 void GRAPH_RDLOCK bdrv_parent_drained_end_single(BdrvChild *c); 393 394 /** 395 * bdrv_drain_poll: 396 * 397 * Poll for pending requests in @bs and its parents (except for @ignore_parent). 398 * 399 * If @ignore_bds_parents is true, parents that are BlockDriverStates must 400 * ignore the drain request because they will be drained separately (used for 401 * drain_all). 402 * 403 * This is part of bdrv_drained_begin. 404 */ 405 bool GRAPH_RDLOCK 406 bdrv_drain_poll(BlockDriverState *bs, BdrvChild *ignore_parent, 407 bool ignore_bds_parents); 408 409 /** 410 * bdrv_drained_begin: 411 * 412 * Begin a quiesced section for exclusive access to the BDS, by disabling 413 * external request sources including NBD server, block jobs, and device model. 414 * 415 * This function can only be invoked by the main loop or a coroutine 416 * (regardless of the AioContext where it is running). 417 * If the coroutine is running in an Iothread AioContext, this function will 418 * just schedule a BH to run in the main loop. 419 * However, it cannot be directly called by an Iothread. 420 * 421 * This function can be recursive. 422 */ 423 void bdrv_drained_begin(BlockDriverState *bs); 424 425 /** 426 * bdrv_do_drained_begin_quiesce: 427 * 428 * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already 429 * running requests to complete. 430 */ 431 void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent); 432 433 /** 434 * bdrv_drained_end: 435 * 436 * End a quiescent section started by bdrv_drained_begin(). 437 * 438 * This function can only be invoked by the main loop or a coroutine 439 * (regardless of the AioContext where it is running). 440 * If the coroutine is running in an Iothread AioContext, this function will 441 * just schedule a BH to run in the main loop. 442 * However, it cannot be directly called by an Iothread. 443 */ 444 void bdrv_drained_end(BlockDriverState *bs); 445 446 #endif /* BLOCK_IO_H */ 447