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