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 int bdrv_block_status(BlockDriverState *bs, int64_t offset, 131 int64_t bytes, int64_t *pnum, int64_t *map, 132 BlockDriverState **file); 133 134 int coroutine_fn GRAPH_RDLOCK 135 bdrv_co_block_status_above(BlockDriverState *bs, BlockDriverState *base, 136 int64_t offset, int64_t bytes, int64_t *pnum, 137 int64_t *map, BlockDriverState **file); 138 int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base, 139 int64_t offset, int64_t bytes, int64_t *pnum, 140 int64_t *map, BlockDriverState **file); 141 142 int coroutine_fn GRAPH_RDLOCK 143 bdrv_co_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes, 144 int64_t *pnum); 145 int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes, 146 int64_t *pnum); 147 148 int coroutine_fn GRAPH_RDLOCK 149 bdrv_co_is_allocated_above(BlockDriverState *top, BlockDriverState *base, 150 bool include_base, int64_t offset, int64_t bytes, 151 int64_t *pnum); 152 int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base, 153 bool include_base, int64_t offset, int64_t bytes, 154 int64_t *pnum); 155 156 int coroutine_fn GRAPH_RDLOCK 157 bdrv_co_is_zero_fast(BlockDriverState *bs, int64_t offset, int64_t bytes); 158 159 int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg, 160 Error **errp); 161 bool bdrv_is_read_only(BlockDriverState *bs); 162 bool bdrv_is_writable(BlockDriverState *bs); 163 bool bdrv_is_sg(BlockDriverState *bs); 164 int bdrv_get_flags(BlockDriverState *bs); 165 166 bool coroutine_fn GRAPH_RDLOCK bdrv_co_is_inserted(BlockDriverState *bs); 167 bool co_wrapper_bdrv_rdlock bdrv_is_inserted(BlockDriverState *bs); 168 169 void coroutine_fn GRAPH_RDLOCK 170 bdrv_co_lock_medium(BlockDriverState *bs, bool locked); 171 172 void coroutine_fn GRAPH_RDLOCK 173 bdrv_co_eject(BlockDriverState *bs, bool eject_flag); 174 175 const char *bdrv_get_format_name(BlockDriverState *bs); 176 177 bool bdrv_supports_compressed_writes(BlockDriverState *bs); 178 const char *bdrv_get_node_name(const BlockDriverState *bs); 179 const char *bdrv_get_device_name(const BlockDriverState *bs); 180 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs); 181 182 int coroutine_fn GRAPH_RDLOCK 183 bdrv_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi); 184 185 int co_wrapper_mixed_bdrv_rdlock 186 bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi); 187 188 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs, 189 Error **errp); 190 BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs); 191 void bdrv_round_to_subclusters(BlockDriverState *bs, 192 int64_t offset, int64_t bytes, 193 int64_t *cluster_offset, 194 int64_t *cluster_bytes); 195 196 void bdrv_get_backing_filename(BlockDriverState *bs, 197 char *filename, int filename_size); 198 199 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf, 200 int64_t pos, int size); 201 202 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf, 203 int64_t pos, int size); 204 205 /* 206 * Returns the alignment in bytes that is required so that no bounce buffer 207 * is required throughout the stack 208 */ 209 size_t bdrv_min_mem_align(BlockDriverState *bs); 210 /* Returns optimal alignment in bytes for bounce buffer */ 211 size_t bdrv_opt_mem_align(BlockDriverState *bs); 212 void *qemu_blockalign(BlockDriverState *bs, size_t size); 213 void *qemu_blockalign0(BlockDriverState *bs, size_t size); 214 void *qemu_try_blockalign(BlockDriverState *bs, size_t size); 215 void *qemu_try_blockalign0(BlockDriverState *bs, size_t size); 216 217 void bdrv_enable_copy_on_read(BlockDriverState *bs); 218 void bdrv_disable_copy_on_read(BlockDriverState *bs); 219 220 void coroutine_fn GRAPH_RDLOCK 221 bdrv_co_debug_event(BlockDriverState *bs, BlkdebugEvent event); 222 223 void co_wrapper_mixed_bdrv_rdlock 224 bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event); 225 226 #define BLKDBG_CO_EVENT(child, evt) \ 227 do { \ 228 if (child) { \ 229 bdrv_co_debug_event(child->bs, evt); \ 230 } \ 231 } while (0) 232 233 #define BLKDBG_EVENT(child, evt) \ 234 do { \ 235 if (child) { \ 236 bdrv_debug_event(child->bs, evt); \ 237 } \ 238 } while (0) 239 240 /** 241 * bdrv_get_aio_context: 242 * 243 * Returns: the currently bound #AioContext 244 */ 245 AioContext *bdrv_get_aio_context(BlockDriverState *bs); 246 247 AioContext *bdrv_child_get_parent_aio_context(BdrvChild *c); 248 249 /** 250 * Move the current coroutine to the AioContext of @bs and return the old 251 * AioContext of the coroutine. Increase bs->in_flight so that draining @bs 252 * will wait for the operation to proceed until the corresponding 253 * bdrv_co_leave(). 254 * 255 * Consequently, you can't call drain inside a bdrv_co_enter/leave() section as 256 * this will deadlock. 257 */ 258 AioContext *coroutine_fn bdrv_co_enter(BlockDriverState *bs); 259 260 /** 261 * Ends a section started by bdrv_co_enter(). Move the current coroutine back 262 * to old_ctx and decrease bs->in_flight again. 263 */ 264 void coroutine_fn bdrv_co_leave(BlockDriverState *bs, AioContext *old_ctx); 265 266 AioContext *child_of_bds_get_parent_aio_context(BdrvChild *c); 267 268 bool coroutine_fn GRAPH_RDLOCK 269 bdrv_co_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name, 270 uint32_t granularity, Error **errp); 271 bool co_wrapper_bdrv_rdlock 272 bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name, 273 uint32_t granularity, Error **errp); 274 275 /** 276 * 277 * bdrv_co_copy_range: 278 * 279 * Do offloaded copy between two children. If the operation is not implemented 280 * by the driver, or if the backend storage doesn't support it, a negative 281 * error code will be returned. 282 * 283 * Note: block layer doesn't emulate or fallback to a bounce buffer approach 284 * because usually the caller shouldn't attempt offloaded copy any more (e.g. 285 * calling copy_file_range(2)) after the first error, thus it should fall back 286 * to a read+write path in the caller level. 287 * 288 * @src: Source child to copy data from 289 * @src_offset: offset in @src image to read data 290 * @dst: Destination child to copy data to 291 * @dst_offset: offset in @dst image to write data 292 * @bytes: number of bytes to copy 293 * @flags: request flags. Supported flags: 294 * BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero 295 * write on @dst as if bdrv_co_pwrite_zeroes is 296 * called. Used to simplify caller code, or 297 * during BlockDriver.bdrv_co_copy_range_from() 298 * recursion. 299 * BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping 300 * requests currently in flight. 301 * 302 * Returns: 0 if succeeded; negative error code if failed. 303 **/ 304 int coroutine_fn GRAPH_RDLOCK 305 bdrv_co_copy_range(BdrvChild *src, int64_t src_offset, 306 BdrvChild *dst, int64_t dst_offset, 307 int64_t bytes, BdrvRequestFlags read_flags, 308 BdrvRequestFlags write_flags); 309 310 /* 311 * "I/O or GS" API functions. These functions can run without 312 * the BQL, but only in one specific iothread/main loop. 313 * 314 * More specifically, these functions use BDRV_POLL_WHILE(bs), which 315 * requires the caller to be either in the main thread and hold 316 * the BlockdriverState (bs) AioContext lock, or directly in the 317 * home thread that runs the bs AioContext. Calling them from 318 * another thread in another AioContext would cause deadlocks. 319 * 320 * Therefore, these functions are not proper I/O, because they 321 * can't run in *any* iothreads, but only in a specific one. 322 * 323 * These functions can call any function from I/O, Common and this 324 * categories, but must be invoked only by other "I/O or GS" and GS APIs. 325 * 326 * All functions in this category must use the macro 327 * IO_OR_GS_CODE(); 328 * to catch when they are accidentally called by the wrong API. 329 */ 330 331 #define BDRV_POLL_WHILE(bs, cond) ({ \ 332 BlockDriverState *bs_ = (bs); \ 333 IO_OR_GS_CODE(); \ 334 AIO_WAIT_WHILE(bdrv_get_aio_context(bs_), \ 335 cond); }) 336 337 void bdrv_drain(BlockDriverState *bs); 338 339 int co_wrapper_mixed_bdrv_rdlock 340 bdrv_truncate(BdrvChild *child, int64_t offset, bool exact, 341 PreallocMode prealloc, BdrvRequestFlags flags, Error **errp); 342 343 int co_wrapper_mixed_bdrv_rdlock 344 bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix); 345 346 /* Invalidate any cached metadata used by image formats */ 347 int co_wrapper_mixed_bdrv_rdlock 348 bdrv_invalidate_cache(BlockDriverState *bs, Error **errp); 349 350 int co_wrapper_mixed_bdrv_rdlock bdrv_flush(BlockDriverState *bs); 351 352 int co_wrapper_mixed_bdrv_rdlock 353 bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes); 354 355 int co_wrapper_mixed_bdrv_rdlock 356 bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); 357 358 int co_wrapper_mixed_bdrv_rdlock 359 bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); 360 361 /** 362 * bdrv_parent_drained_begin_single: 363 * 364 * Begin a quiesced section for the parent of @c. 365 */ 366 void bdrv_parent_drained_begin_single(BdrvChild *c); 367 368 /** 369 * bdrv_parent_drained_poll_single: 370 * 371 * Returns true if there is any pending activity to cease before @c can be 372 * called quiesced, false otherwise. 373 */ 374 bool bdrv_parent_drained_poll_single(BdrvChild *c); 375 376 /** 377 * bdrv_parent_drained_end_single: 378 * 379 * End a quiesced section for the parent of @c. 380 */ 381 void bdrv_parent_drained_end_single(BdrvChild *c); 382 383 /** 384 * bdrv_drain_poll: 385 * 386 * Poll for pending requests in @bs and its parents (except for @ignore_parent). 387 * 388 * If @ignore_bds_parents is true, parents that are BlockDriverStates must 389 * ignore the drain request because they will be drained separately (used for 390 * drain_all). 391 * 392 * This is part of bdrv_drained_begin. 393 */ 394 bool bdrv_drain_poll(BlockDriverState *bs, BdrvChild *ignore_parent, 395 bool ignore_bds_parents); 396 397 /** 398 * bdrv_drained_begin: 399 * 400 * Begin a quiesced section for exclusive access to the BDS, by disabling 401 * external request sources including NBD server, block jobs, and device model. 402 * 403 * This function can be recursive. 404 */ 405 void bdrv_drained_begin(BlockDriverState *bs); 406 407 /** 408 * bdrv_do_drained_begin_quiesce: 409 * 410 * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already 411 * running requests to complete. 412 */ 413 void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent); 414 415 /** 416 * bdrv_drained_end: 417 * 418 * End a quiescent section started by bdrv_drained_begin(). 419 */ 420 void bdrv_drained_end(BlockDriverState *bs); 421 422 #endif /* BLOCK_IO_H */ 423