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