include/block/block-io.h

   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 void coroutine_fn GRAPH_RDLOCK bdrv_co_io_plug(BlockDriverState *bs);
 263 void coroutine_fn GRAPH_RDLOCK bdrv_co_io_unplug(BlockDriverState *bs);
 264
 265 bool coroutine_fn GRAPH_RDLOCK
 266 bdrv_co_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
 267                                    uint32_t granularity, Error **errp);
 268 bool co_wrapper_bdrv_rdlock
 269 bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
 270                                 uint32_t granularity, Error **errp);
 271
 272 /**
 273  *
 274  * bdrv_co_copy_range:
 275  *
 276  * Do offloaded copy between two children. If the operation is not implemented
 277  * by the driver, or if the backend storage doesn't support it, a negative
 278  * error code will be returned.
 279  *
 280  * Note: block layer doesn't emulate or fallback to a bounce buffer approach
 281  * because usually the caller shouldn't attempt offloaded copy any more (e.g.
 282  * calling copy_file_range(2)) after the first error, thus it should fall back
 283  * to a read+write path in the caller level.
 284  *
 285  * @src: Source child to copy data from
 286  * @src_offset: offset in @src image to read data
 287  * @dst: Destination child to copy data to
 288  * @dst_offset: offset in @dst image to write data
 289  * @bytes: number of bytes to copy
 290  * @flags: request flags. Supported flags:
 291  *         BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero
 292  *                               write on @dst as if bdrv_co_pwrite_zeroes is
 293  *                               called. Used to simplify caller code, or
 294  *                               during BlockDriver.bdrv_co_copy_range_from()
 295  *                               recursion.
 296  *         BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping
 297  *                                   requests currently in flight.
 298  *
 299  * Returns: 0 if succeeded; negative error code if failed.
 300  **/
 301 int coroutine_fn GRAPH_RDLOCK
 302 bdrv_co_copy_range(BdrvChild *src, int64_t src_offset,
 303                    BdrvChild *dst, int64_t dst_offset,
 304                    int64_t bytes, BdrvRequestFlags read_flags,
 305                    BdrvRequestFlags write_flags);
 306
 307 /*
 308  * "I/O or GS" API functions. These functions can run without
 309  * the BQL, but only in one specific iothread/main loop.
 310  *
 311  * More specifically, these functions use BDRV_POLL_WHILE(bs), which
 312  * requires the caller to be either in the main thread and hold
 313  * the BlockdriverState (bs) AioContext lock, or directly in the
 314  * home thread that runs the bs AioContext. Calling them from
 315  * another thread in another AioContext would cause deadlocks.
 316  *
 317  * Therefore, these functions are not proper I/O, because they
 318  * can't run in *any* iothreads, but only in a specific one.
 319  *
 320  * These functions can call any function from I/O, Common and this
 321  * categories, but must be invoked only by other "I/O or GS" and GS APIs.
 322  *
 323  * All functions in this category must use the macro
 324  * IO_OR_GS_CODE();
 325  * to catch when they are accidentally called by the wrong API.
 326  */
 327
 328 #define BDRV_POLL_WHILE(bs, cond) ({                       \
 329     BlockDriverState *bs_ = (bs);                          \
 330     IO_OR_GS_CODE();                                       \
 331     AIO_WAIT_WHILE(bdrv_get_aio_context(bs_),              \
 332                    cond); })
 333
 334 void bdrv_drain(BlockDriverState *bs);
 335
 336 int co_wrapper_mixed_bdrv_rdlock
 337 bdrv_truncate(BdrvChild *child, int64_t offset, bool exact,
 338               PreallocMode prealloc, BdrvRequestFlags flags, Error **errp);
 339
 340 int co_wrapper_mixed_bdrv_rdlock
 341 bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
 342
 343 /* Invalidate any cached metadata used by image formats */
 344 int co_wrapper_mixed_bdrv_rdlock
 345 bdrv_invalidate_cache(BlockDriverState *bs, Error **errp);
 346
 347 int co_wrapper_mixed_bdrv_rdlock bdrv_flush(BlockDriverState *bs);
 348
 349 int co_wrapper_mixed_bdrv_rdlock
 350 bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
 351
 352 int co_wrapper_mixed_bdrv_rdlock
 353 bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 354
 355 int co_wrapper_mixed_bdrv_rdlock
 356 bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 357
 358 /**
 359  * bdrv_parent_drained_begin_single:
 360  *
 361  * Begin a quiesced section for the parent of @c.
 362  */
 363 void bdrv_parent_drained_begin_single(BdrvChild *c);
 364
 365 /**
 366  * bdrv_parent_drained_poll_single:
 367  *
 368  * Returns true if there is any pending activity to cease before @c can be
 369  * called quiesced, false otherwise.
 370  */
 371 bool bdrv_parent_drained_poll_single(BdrvChild *c);
 372
 373 /**
 374  * bdrv_parent_drained_end_single:
 375  *
 376  * End a quiesced section for the parent of @c.
 377  */
 378 void bdrv_parent_drained_end_single(BdrvChild *c);
 379
 380 /**
 381  * bdrv_drain_poll:
 382  *
 383  * Poll for pending requests in @bs and its parents (except for @ignore_parent).
 384  *
 385  * If @ignore_bds_parents is true, parents that are BlockDriverStates must
 386  * ignore the drain request because they will be drained separately (used for
 387  * drain_all).
 388  *
 389  * This is part of bdrv_drained_begin.
 390  */
 391 bool bdrv_drain_poll(BlockDriverState *bs, BdrvChild *ignore_parent,
 392                      bool ignore_bds_parents);
 393
 394 /**
 395  * bdrv_drained_begin:
 396  *
 397  * Begin a quiesced section for exclusive access to the BDS, by disabling
 398  * external request sources including NBD server, block jobs, and device model.
 399  *
 400  * This function can be recursive.
 401  */
 402 void bdrv_drained_begin(BlockDriverState *bs);
 403
 404 /**
 405  * bdrv_do_drained_begin_quiesce:
 406  *
 407  * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already
 408  * running requests to complete.
 409  */
 410 void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent);
 411
 412 /**
 413  * bdrv_drained_end:
 414  *
 415  * End a quiescent section started by bdrv_drained_begin().
 416  */
 417 void bdrv_drained_end(BlockDriverState *bs);
 418
 419 #endif /* BLOCK_IO_H */