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 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 AioContext *child_of_bds_get_parent_aio_context(BdrvChild *c);
 217
 218 void coroutine_fn bdrv_co_io_plug(BlockDriverState *bs);
 219 void coroutine_fn bdrv_co_io_unplug(BlockDriverState *bs);
 220
 221 bool coroutine_fn bdrv_co_can_store_new_dirty_bitmap(BlockDriverState *bs,
 222                                                      const char *name,
 223                                                      uint32_t granularity,
 224                                                      Error **errp);
 225 bool co_wrapper bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs,
 226                                                 const char *name,
 227                                                 uint32_t granularity,
 228                                                 Error **errp);
 229
 230 /**
 231  *
 232  * bdrv_co_copy_range:
 233  *
 234  * Do offloaded copy between two children. If the operation is not implemented
 235  * by the driver, or if the backend storage doesn't support it, a negative
 236  * error code will be returned.
 237  *
 238  * Note: block layer doesn't emulate or fallback to a bounce buffer approach
 239  * because usually the caller shouldn't attempt offloaded copy any more (e.g.
 240  * calling copy_file_range(2)) after the first error, thus it should fall back
 241  * to a read+write path in the caller level.
 242  *
 243  * @src: Source child to copy data from
 244  * @src_offset: offset in @src image to read data
 245  * @dst: Destination child to copy data to
 246  * @dst_offset: offset in @dst image to write data
 247  * @bytes: number of bytes to copy
 248  * @flags: request flags. Supported flags:
 249  *         BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero
 250  *                               write on @dst as if bdrv_co_pwrite_zeroes is
 251  *                               called. Used to simplify caller code, or
 252  *                               during BlockDriver.bdrv_co_copy_range_from()
 253  *                               recursion.
 254  *         BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping
 255  *                                   requests currently in flight.
 256  *
 257  * Returns: 0 if succeeded; negative error code if failed.
 258  **/
 259 int coroutine_fn bdrv_co_copy_range(BdrvChild *src, int64_t src_offset,
 260                                     BdrvChild *dst, int64_t dst_offset,
 261                                     int64_t bytes, BdrvRequestFlags read_flags,
 262                                     BdrvRequestFlags write_flags);
 263
 264 /*
 265  * "I/O or GS" API functions. These functions can run without
 266  * the BQL, but only in one specific iothread/main loop.
 267  *
 268  * More specifically, these functions use BDRV_POLL_WHILE(bs), which
 269  * requires the caller to be either in the main thread and hold
 270  * the BlockdriverState (bs) AioContext lock, or directly in the
 271  * home thread that runs the bs AioContext. Calling them from
 272  * another thread in another AioContext would cause deadlocks.
 273  *
 274  * Therefore, these functions are not proper I/O, because they
 275  * can't run in *any* iothreads, but only in a specific one.
 276  *
 277  * These functions can call any function from I/O, Common and this
 278  * categories, but must be invoked only by other "I/O or GS" and GS APIs.
 279  *
 280  * All functions in this category must use the macro
 281  * IO_OR_GS_CODE();
 282  * to catch when they are accidentally called by the wrong API.
 283  */
 284
 285 #define BDRV_POLL_WHILE(bs, cond) ({                       \
 286     BlockDriverState *bs_ = (bs);                          \
 287     IO_OR_GS_CODE();                                       \
 288     AIO_WAIT_WHILE(bdrv_get_aio_context(bs_),              \
 289                    cond); })
 290
 291 void bdrv_drain(BlockDriverState *bs);
 292
 293 int co_wrapper_mixed_bdrv_rdlock
 294 bdrv_truncate(BdrvChild *child, int64_t offset, bool exact,
 295               PreallocMode prealloc, BdrvRequestFlags flags, Error **errp);
 296
 297 int co_wrapper_mixed_bdrv_rdlock
 298 bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
 299
 300 /* Invalidate any cached metadata used by image formats */
 301 int co_wrapper_mixed_bdrv_rdlock
 302 bdrv_invalidate_cache(BlockDriverState *bs, Error **errp);
 303
 304 int co_wrapper_mixed_bdrv_rdlock bdrv_flush(BlockDriverState *bs);
 305
 306 int co_wrapper_mixed_bdrv_rdlock
 307 bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
 308
 309 int co_wrapper_mixed_bdrv_rdlock
 310 bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 311
 312 int co_wrapper_mixed_bdrv_rdlock
 313 bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 314
 315 /**
 316  * bdrv_parent_drained_begin_single:
 317  *
 318  * Begin a quiesced section for the parent of @c.
 319  */
 320 void bdrv_parent_drained_begin_single(BdrvChild *c);
 321
 322 /**
 323  * bdrv_parent_drained_poll_single:
 324  *
 325  * Returns true if there is any pending activity to cease before @c can be
 326  * called quiesced, false otherwise.
 327  */
 328 bool bdrv_parent_drained_poll_single(BdrvChild *c);
 329
 330 /**
 331  * bdrv_parent_drained_end_single:
 332  *
 333  * End a quiesced section for the parent of @c.
 334  */
 335 void bdrv_parent_drained_end_single(BdrvChild *c);
 336
 337 /**
 338  * bdrv_drain_poll:
 339  *
 340  * Poll for pending requests in @bs and its parents (except for @ignore_parent).
 341  *
 342  * If @ignore_bds_parents is true, parents that are BlockDriverStates must
 343  * ignore the drain request because they will be drained separately (used for
 344  * drain_all).
 345  *
 346  * This is part of bdrv_drained_begin.
 347  */
 348 bool bdrv_drain_poll(BlockDriverState *bs, BdrvChild *ignore_parent,
 349                      bool ignore_bds_parents);
 350
 351 /**
 352  * bdrv_drained_begin:
 353  *
 354  * Begin a quiesced section for exclusive access to the BDS, by disabling
 355  * external request sources including NBD server, block jobs, and device model.
 356  *
 357  * This function can be recursive.
 358  */
 359 void bdrv_drained_begin(BlockDriverState *bs);
 360
 361 /**
 362  * bdrv_do_drained_begin_quiesce:
 363  *
 364  * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already
 365  * running requests to complete.
 366  */
 367 void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent);
 368
 369 /**
 370  * bdrv_drained_end:
 371  *
 372  * End a quiescent section started by bdrv_drained_begin().
 373  */
 374 void bdrv_drained_end(BlockDriverState *bs);
 375
 376 #endif /* BLOCK_IO_H */