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