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 bdrv_co_pwrite_sync(BdrvChild *child, int64_t offset, 64 int64_t bytes, const void *buf, 65 BdrvRequestFlags flags); 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 bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset, 73 int64_t bytes, BdrvRequestFlags flags); 74 75 int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact, 76 PreallocMode prealloc, BdrvRequestFlags flags, 77 Error **errp); 78 79 int64_t bdrv_nb_sectors(BlockDriverState *bs); 80 int64_t bdrv_getlength(BlockDriverState *bs); 81 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs); 82 BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts, 83 BlockDriverState *in_bs, Error **errp); 84 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr); 85 int coroutine_fn bdrv_co_delete_file(BlockDriverState *bs, Error **errp); 86 void coroutine_fn bdrv_co_delete_file_noerr(BlockDriverState *bs); 87 88 89 /* async block I/O */ 90 void bdrv_aio_cancel(BlockAIOCB *acb); 91 void bdrv_aio_cancel_async(BlockAIOCB *acb); 92 93 /* sg packet commands */ 94 int coroutine_fn bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf); 95 96 /* Ensure contents are flushed to disk. */ 97 int coroutine_fn bdrv_co_flush(BlockDriverState *bs); 98 99 int coroutine_fn bdrv_co_pdiscard(BdrvChild *child, int64_t offset, 100 int64_t bytes); 101 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs); 102 int bdrv_block_status(BlockDriverState *bs, int64_t offset, 103 int64_t bytes, int64_t *pnum, int64_t *map, 104 BlockDriverState **file); 105 106 int coroutine_fn bdrv_co_block_status_above(BlockDriverState *bs, 107 BlockDriverState *base, 108 int64_t offset, int64_t bytes, 109 int64_t *pnum, int64_t *map, 110 BlockDriverState **file); 111 int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base, 112 int64_t offset, int64_t bytes, int64_t *pnum, 113 int64_t *map, BlockDriverState **file); 114 115 int coroutine_fn bdrv_co_is_allocated(BlockDriverState *bs, int64_t offset, 116 int64_t bytes, int64_t *pnum); 117 int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes, 118 int64_t *pnum); 119 120 int coroutine_fn bdrv_co_is_allocated_above(BlockDriverState *top, 121 BlockDriverState *base, 122 bool include_base, int64_t offset, 123 int64_t bytes, int64_t *pnum); 124 int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base, 125 bool include_base, int64_t offset, int64_t bytes, 126 int64_t *pnum); 127 128 int coroutine_fn bdrv_co_is_zero_fast(BlockDriverState *bs, int64_t offset, 129 int64_t bytes); 130 131 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only, 132 bool ignore_allow_rdw, Error **errp); 133 int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg, 134 Error **errp); 135 bool bdrv_is_read_only(BlockDriverState *bs); 136 bool bdrv_is_writable(BlockDriverState *bs); 137 bool bdrv_is_sg(BlockDriverState *bs); 138 int bdrv_get_flags(BlockDriverState *bs); 139 bool bdrv_is_inserted(BlockDriverState *bs); 140 void bdrv_lock_medium(BlockDriverState *bs, bool locked); 141 void bdrv_eject(BlockDriverState *bs, bool eject_flag); 142 const char *bdrv_get_format_name(BlockDriverState *bs); 143 144 bool bdrv_supports_compressed_writes(BlockDriverState *bs); 145 const char *bdrv_get_node_name(const BlockDriverState *bs); 146 const char *bdrv_get_device_name(const BlockDriverState *bs); 147 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs); 148 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi); 149 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs, 150 Error **errp); 151 BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs); 152 void bdrv_round_to_clusters(BlockDriverState *bs, 153 int64_t offset, int64_t bytes, 154 int64_t *cluster_offset, 155 int64_t *cluster_bytes); 156 157 void bdrv_get_backing_filename(BlockDriverState *bs, 158 char *filename, int filename_size); 159 160 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf, 161 int64_t pos, int size); 162 163 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf, 164 int64_t pos, int size); 165 166 /* 167 * Returns the alignment in bytes that is required so that no bounce buffer 168 * is required throughout the stack 169 */ 170 size_t bdrv_min_mem_align(BlockDriverState *bs); 171 /* Returns optimal alignment in bytes for bounce buffer */ 172 size_t bdrv_opt_mem_align(BlockDriverState *bs); 173 void *qemu_blockalign(BlockDriverState *bs, size_t size); 174 void *qemu_blockalign0(BlockDriverState *bs, size_t size); 175 void *qemu_try_blockalign(BlockDriverState *bs, size_t size); 176 void *qemu_try_blockalign0(BlockDriverState *bs, size_t size); 177 178 void bdrv_enable_copy_on_read(BlockDriverState *bs); 179 void bdrv_disable_copy_on_read(BlockDriverState *bs); 180 181 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event); 182 183 #define BLKDBG_EVENT(child, evt) \ 184 do { \ 185 if (child) { \ 186 bdrv_debug_event(child->bs, evt); \ 187 } \ 188 } while (0) 189 190 /** 191 * bdrv_get_aio_context: 192 * 193 * Returns: the currently bound #AioContext 194 */ 195 AioContext *bdrv_get_aio_context(BlockDriverState *bs); 196 197 AioContext *bdrv_child_get_parent_aio_context(BdrvChild *c); 198 199 /** 200 * Move the current coroutine to the AioContext of @bs and return the old 201 * AioContext of the coroutine. Increase bs->in_flight so that draining @bs 202 * will wait for the operation to proceed until the corresponding 203 * bdrv_co_leave(). 204 * 205 * Consequently, you can't call drain inside a bdrv_co_enter/leave() section as 206 * this will deadlock. 207 */ 208 AioContext *coroutine_fn bdrv_co_enter(BlockDriverState *bs); 209 210 /** 211 * Ends a section started by bdrv_co_enter(). Move the current coroutine back 212 * to old_ctx and decrease bs->in_flight again. 213 */ 214 void coroutine_fn bdrv_co_leave(BlockDriverState *bs, AioContext *old_ctx); 215 216 /** 217 * Transfer control to @co in the aio context of @bs 218 */ 219 void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co); 220 221 AioContext *child_of_bds_get_parent_aio_context(BdrvChild *c); 222 223 void bdrv_io_plug(BlockDriverState *bs); 224 void bdrv_io_unplug(BlockDriverState *bs); 225 226 bool coroutine_fn bdrv_co_can_store_new_dirty_bitmap(BlockDriverState *bs, 227 const char *name, 228 uint32_t granularity, 229 Error **errp); 230 bool co_wrapper bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, 231 const char *name, 232 uint32_t granularity, 233 Error **errp); 234 235 /** 236 * 237 * bdrv_co_copy_range: 238 * 239 * Do offloaded copy between two children. If the operation is not implemented 240 * by the driver, or if the backend storage doesn't support it, a negative 241 * error code will be returned. 242 * 243 * Note: block layer doesn't emulate or fallback to a bounce buffer approach 244 * because usually the caller shouldn't attempt offloaded copy any more (e.g. 245 * calling copy_file_range(2)) after the first error, thus it should fall back 246 * to a read+write path in the caller level. 247 * 248 * @src: Source child to copy data from 249 * @src_offset: offset in @src image to read data 250 * @dst: Destination child to copy data to 251 * @dst_offset: offset in @dst image to write data 252 * @bytes: number of bytes to copy 253 * @flags: request flags. Supported flags: 254 * BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero 255 * write on @dst as if bdrv_co_pwrite_zeroes is 256 * called. Used to simplify caller code, or 257 * during BlockDriver.bdrv_co_copy_range_from() 258 * recursion. 259 * BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping 260 * requests currently in flight. 261 * 262 * Returns: 0 if succeeded; negative error code if failed. 263 **/ 264 int coroutine_fn bdrv_co_copy_range(BdrvChild *src, int64_t src_offset, 265 BdrvChild *dst, int64_t dst_offset, 266 int64_t bytes, BdrvRequestFlags read_flags, 267 BdrvRequestFlags write_flags); 268 269 /* 270 * "I/O or GS" API functions. These functions can run without 271 * the BQL, but only in one specific iothread/main loop. 272 * 273 * More specifically, these functions use BDRV_POLL_WHILE(bs), which 274 * requires the caller to be either in the main thread and hold 275 * the BlockdriverState (bs) AioContext lock, or directly in the 276 * home thread that runs the bs AioContext. Calling them from 277 * another thread in another AioContext would cause deadlocks. 278 * 279 * Therefore, these functions are not proper I/O, because they 280 * can't run in *any* iothreads, but only in a specific one. 281 * 282 * These functions can call any function from I/O, Common and this 283 * categories, but must be invoked only by other "I/O or GS" and GS APIs. 284 * 285 * All functions in this category must use the macro 286 * IO_OR_GS_CODE(); 287 * to catch when they are accidentally called by the wrong API. 288 */ 289 290 #define BDRV_POLL_WHILE(bs, cond) ({ \ 291 BlockDriverState *bs_ = (bs); \ 292 IO_OR_GS_CODE(); \ 293 AIO_WAIT_WHILE(bdrv_get_aio_context(bs_), \ 294 cond); }) 295 296 void bdrv_drain(BlockDriverState *bs); 297 298 int co_wrapper_mixed_bdrv_rdlock 299 bdrv_truncate(BdrvChild *child, int64_t offset, bool exact, 300 PreallocMode prealloc, BdrvRequestFlags flags, Error **errp); 301 302 int co_wrapper_mixed_bdrv_rdlock 303 bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix); 304 305 /* Invalidate any cached metadata used by image formats */ 306 int co_wrapper_mixed_bdrv_rdlock 307 bdrv_invalidate_cache(BlockDriverState *bs, Error **errp); 308 309 int co_wrapper_mixed_bdrv_rdlock bdrv_flush(BlockDriverState *bs); 310 311 int co_wrapper_mixed_bdrv_rdlock 312 bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes); 313 314 int co_wrapper_mixed_bdrv_rdlock 315 bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); 316 317 int co_wrapper_mixed_bdrv_rdlock 318 bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos); 319 320 /** 321 * bdrv_parent_drained_begin_single: 322 * 323 * Begin a quiesced section for the parent of @c. 324 */ 325 void bdrv_parent_drained_begin_single(BdrvChild *c); 326 327 /** 328 * bdrv_parent_drained_poll_single: 329 * 330 * Returns true if there is any pending activity to cease before @c can be 331 * called quiesced, false otherwise. 332 */ 333 bool bdrv_parent_drained_poll_single(BdrvChild *c); 334 335 /** 336 * bdrv_parent_drained_end_single: 337 * 338 * End a quiesced section for the parent of @c. 339 */ 340 void bdrv_parent_drained_end_single(BdrvChild *c); 341 342 /** 343 * bdrv_drain_poll: 344 * 345 * Poll for pending requests in @bs and its parents (except for @ignore_parent). 346 * 347 * If @ignore_bds_parents is true, parents that are BlockDriverStates must 348 * ignore the drain request because they will be drained separately (used for 349 * drain_all). 350 * 351 * This is part of bdrv_drained_begin. 352 */ 353 bool bdrv_drain_poll(BlockDriverState *bs, BdrvChild *ignore_parent, 354 bool ignore_bds_parents); 355 356 /** 357 * bdrv_drained_begin: 358 * 359 * Begin a quiesced section for exclusive access to the BDS, by disabling 360 * external request sources including NBD server, block jobs, and device model. 361 * 362 * This function can be recursive. 363 */ 364 void bdrv_drained_begin(BlockDriverState *bs); 365 366 /** 367 * bdrv_do_drained_begin_quiesce: 368 * 369 * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already 370 * running requests to complete. 371 */ 372 void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent); 373 374 /** 375 * bdrv_drained_end: 376 * 377 * End a quiescent section started by bdrv_drained_begin(). 378 */ 379 void bdrv_drained_end(BlockDriverState *bs); 380 381 #endif /* BLOCK_IO_H */ 382