include/block/block.h

   1 #ifndef BLOCK_H
   2 #define BLOCK_H
   3
   4 #include "block/aio.h"
   5 #include "block/aio-wait.h"
   6 #include "qemu/iov.h"
   7 #include "qemu/coroutine.h"
   8 #include "block/accounting.h"
   9 #include "block/dirty-bitmap.h"
  10 #include "block/blockjob.h"
  11 #include "qemu/hbitmap.h"
  12
  13 /* block.c */
  14 typedef struct BlockDriver BlockDriver;
  15 typedef struct BdrvChild BdrvChild;
  16 typedef struct BdrvChildRole BdrvChildRole;
  17
  18 typedef struct BlockDriverInfo {
  19     /* in bytes, 0 if irrelevant */
  20     int cluster_size;
  21     /* offset at which the VM state can be saved (0 if not possible) */
  22     int64_t vm_state_offset;
  23     bool is_dirty;
  24     /*
  25      * True if unallocated blocks read back as zeroes. This is equivalent
  26      * to the LBPRZ flag in the SCSI logical block provisioning page.
  27      */
  28     bool unallocated_blocks_are_zero;
  29     /*
  30      * True if this block driver only supports compressed writes
  31      */
  32     bool needs_compressed_writes;
  33 } BlockDriverInfo;
  34
  35 typedef struct BlockFragInfo {
  36     uint64_t allocated_clusters;
  37     uint64_t total_clusters;
  38     uint64_t fragmented_clusters;
  39     uint64_t compressed_clusters;
  40 } BlockFragInfo;
  41
  42 typedef enum {
  43     BDRV_REQ_COPY_ON_READ       = 0x1,
  44     BDRV_REQ_ZERO_WRITE         = 0x2,
  45
  46     /*
  47      * The BDRV_REQ_MAY_UNMAP flag is used in write_zeroes requests to indicate
  48      * that the block driver should unmap (discard) blocks if it is guaranteed
  49      * that the result will read back as zeroes. The flag is only passed to the
  50      * driver if the block device is opened with BDRV_O_UNMAP.
  51      */
  52     BDRV_REQ_MAY_UNMAP          = 0x4,
  53
  54     /*
  55      * The BDRV_REQ_NO_SERIALISING flag is only valid for reads and means that
  56      * we don't want wait_serialising_requests() during the read operation.
  57      *
  58      * This flag is used for backup copy-on-write operations, when we need to
  59      * read old data before write (write notifier triggered). It is okay since
  60      * we already waited for other serializing requests in the initiating write
  61      * (see bdrv_aligned_pwritev), and it is necessary if the initiating write
  62      * is already serializing (without the flag, the read would deadlock
  63      * waiting for the serialising write to complete).
  64      */
  65     BDRV_REQ_NO_SERIALISING     = 0x8,
  66     BDRV_REQ_FUA                = 0x10,
  67     BDRV_REQ_WRITE_COMPRESSED   = 0x20,
  68
  69     /* Signifies that this write request will not change the visible disk
  70      * content. */
  71     BDRV_REQ_WRITE_UNCHANGED    = 0x40,
  72
  73     /*
  74      * BDRV_REQ_SERIALISING forces request serialisation for writes.
  75      * It is used to ensure that writes to the backing file of a backup process
  76      * target cannot race with a read of the backup target that defers to the
  77      * backing file.
  78      *
  79      * Note, that BDRV_REQ_SERIALISING is _not_ opposite in meaning to
  80      * BDRV_REQ_NO_SERIALISING. A more descriptive name for the latter might be
  81      * _DO_NOT_WAIT_FOR_SERIALISING, except that is too long.
  82      */
  83     BDRV_REQ_SERIALISING        = 0x80,
  84
  85     /* Execute the request only if the operation can be offloaded or otherwise
  86      * be executed efficiently, but return an error instead of using a slow
  87      * fallback. */
  88     BDRV_REQ_NO_FALLBACK        = 0x100,
  89
  90     /*
  91      * BDRV_REQ_PREFETCH may be used only together with BDRV_REQ_COPY_ON_READ
  92      * on read request and means that caller doesn't really need data to be
  93      * written to qiov parameter which may be NULL.
  94      */
  95     BDRV_REQ_PREFETCH  = 0x200,
  96     /* Mask of valid flags */
  97     BDRV_REQ_MASK               = 0x3ff,
  98 } BdrvRequestFlags;
  99
 100 typedef struct BlockSizes {
 101     uint32_t phys;
 102     uint32_t log;
 103 } BlockSizes;
 104
 105 typedef struct HDGeometry {
 106     uint32_t heads;
 107     uint32_t sectors;
 108     uint32_t cylinders;
 109 } HDGeometry;
 110
 111 #define BDRV_O_RDWR        0x0002
 112 #define BDRV_O_RESIZE      0x0004 /* request permission for resizing the node */
 113 #define BDRV_O_SNAPSHOT    0x0008 /* open the file read only and save writes in a snapshot */
 114 #define BDRV_O_TEMPORARY   0x0010 /* delete the file after use */
 115 #define BDRV_O_NOCACHE     0x0020 /* do not use the host page cache */
 116 #define BDRV_O_NATIVE_AIO  0x0080 /* use native AIO instead of the thread pool */
 117 #define BDRV_O_NO_BACKING  0x0100 /* don't open the backing file */
 118 #define BDRV_O_NO_FLUSH    0x0200 /* disable flushing on this disk */
 119 #define BDRV_O_COPY_ON_READ 0x0400 /* copy read backing sectors into image */
 120 #define BDRV_O_INACTIVE    0x0800  /* consistency hint for migration handoff */
 121 #define BDRV_O_CHECK       0x1000  /* open solely for consistency check */
 122 #define BDRV_O_ALLOW_RDWR  0x2000  /* allow reopen to change from r/o to r/w */
 123 #define BDRV_O_UNMAP       0x4000  /* execute guest UNMAP/TRIM operations */
 124 #define BDRV_O_PROTOCOL    0x8000  /* if no block driver is explicitly given:
 125                                       select an appropriate protocol driver,
 126                                       ignoring the format layer */
 127 #define BDRV_O_NO_IO       0x10000 /* don't initialize for I/O */
 128 #define BDRV_O_AUTO_RDONLY 0x20000 /* degrade to read-only if opening read-write fails */
 129
 130 #define BDRV_O_CACHE_MASK  (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH)
 131
 132
 133 /* Option names of options parsed by the block layer */
 134
 135 #define BDRV_OPT_CACHE_WB       "cache.writeback"
 136 #define BDRV_OPT_CACHE_DIRECT   "cache.direct"
 137 #define BDRV_OPT_CACHE_NO_FLUSH "cache.no-flush"
 138 #define BDRV_OPT_READ_ONLY      "read-only"
 139 #define BDRV_OPT_AUTO_READ_ONLY "auto-read-only"
 140 #define BDRV_OPT_DISCARD        "discard"
 141 #define BDRV_OPT_FORCE_SHARE    "force-share"
 142
 143
 144 #define BDRV_SECTOR_BITS   9
 145 #define BDRV_SECTOR_SIZE   (1ULL << BDRV_SECTOR_BITS)
 146
 147 #define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \
 148                                      INT_MAX >> BDRV_SECTOR_BITS)
 149 #define BDRV_REQUEST_MAX_BYTES (BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS)
 150
 151 /*
 152  * Allocation status flags for bdrv_block_status() and friends.
 153  *
 154  * Public flags:
 155  * BDRV_BLOCK_DATA: allocation for data at offset is tied to this layer
 156  * BDRV_BLOCK_ZERO: offset reads as zero
 157  * BDRV_BLOCK_OFFSET_VALID: an associated offset exists for accessing raw data
 158  * BDRV_BLOCK_ALLOCATED: the content of the block is determined by this
 159  *                       layer rather than any backing, set by block layer
 160  * BDRV_BLOCK_EOF: the returned pnum covers through end of file for this
 161  *                 layer, set by block layer
 162  *
 163  * Internal flags:
 164  * BDRV_BLOCK_RAW: for use by passthrough drivers, such as raw, to request
 165  *                 that the block layer recompute the answer from the returned
 166  *                 BDS; must be accompanied by just BDRV_BLOCK_OFFSET_VALID.
 167  * BDRV_BLOCK_RECURSE: request that the block layer will recursively search for
 168  *                     zeroes in file child of current block node inside
 169  *                     returned region. Only valid together with both
 170  *                     BDRV_BLOCK_DATA and BDRV_BLOCK_OFFSET_VALID. Should not
 171  *                     appear with BDRV_BLOCK_ZERO.
 172  *
 173  * If BDRV_BLOCK_OFFSET_VALID is set, the map parameter represents the
 174  * host offset within the returned BDS that is allocated for the
 175  * corresponding raw guest data.  However, whether that offset
 176  * actually contains data also depends on BDRV_BLOCK_DATA, as follows:
 177  *
 178  * DATA ZERO OFFSET_VALID
 179  *  t    t        t       sectors read as zero, returned file is zero at offset
 180  *  t    f        t       sectors read as valid from file at offset
 181  *  f    t        t       sectors preallocated, read as zero, returned file not
 182  *                        necessarily zero at offset
 183  *  f    f        t       sectors preallocated but read from backing_hd,
 184  *                        returned file contains garbage at offset
 185  *  t    t        f       sectors preallocated, read as zero, unknown offset
 186  *  t    f        f       sectors read from unknown file or offset
 187  *  f    t        f       not allocated or unknown offset, read as zero
 188  *  f    f        f       not allocated or unknown offset, read from backing_hd
 189  */
 190 #define BDRV_BLOCK_DATA         0x01
 191 #define BDRV_BLOCK_ZERO         0x02
 192 #define BDRV_BLOCK_OFFSET_VALID 0x04
 193 #define BDRV_BLOCK_RAW          0x08
 194 #define BDRV_BLOCK_ALLOCATED    0x10
 195 #define BDRV_BLOCK_EOF          0x20
 196 #define BDRV_BLOCK_RECURSE      0x40
 197
 198 typedef QTAILQ_HEAD(BlockReopenQueue, BlockReopenQueueEntry) BlockReopenQueue;
 199
 200 typedef struct BDRVReopenState {
 201     BlockDriverState *bs;
 202     int flags;
 203     BlockdevDetectZeroesOptions detect_zeroes;
 204     bool backing_missing;
 205     bool replace_backing_bs;  /* new_backing_bs is ignored if this is false */
 206     BlockDriverState *new_backing_bs; /* If NULL then detach the current bs */
 207     uint64_t perm, shared_perm;
 208     QDict *options;
 209     QDict *explicit_options;
 210     void *opaque;
 211 } BDRVReopenState;
 212
 213 /*
 214  * Block operation types
 215  */
 216 typedef enum BlockOpType {
 217     BLOCK_OP_TYPE_BACKUP_SOURCE,
 218     BLOCK_OP_TYPE_BACKUP_TARGET,
 219     BLOCK_OP_TYPE_CHANGE,
 220     BLOCK_OP_TYPE_COMMIT_SOURCE,
 221     BLOCK_OP_TYPE_COMMIT_TARGET,
 222     BLOCK_OP_TYPE_DATAPLANE,
 223     BLOCK_OP_TYPE_DRIVE_DEL,
 224     BLOCK_OP_TYPE_EJECT,
 225     BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
 226     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT,
 227     BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
 228     BLOCK_OP_TYPE_MIRROR_SOURCE,
 229     BLOCK_OP_TYPE_MIRROR_TARGET,
 230     BLOCK_OP_TYPE_RESIZE,
 231     BLOCK_OP_TYPE_STREAM,
 232     BLOCK_OP_TYPE_REPLACE,
 233     BLOCK_OP_TYPE_MAX,
 234 } BlockOpType;
 235
 236 /* Block node permission constants */
 237 enum {
 238     /**
 239      * A user that has the "permission" of consistent reads is guaranteed that
 240      * their view of the contents of the block device is complete and
 241      * self-consistent, representing the contents of a disk at a specific
 242      * point.
 243      *
 244      * For most block devices (including their backing files) this is true, but
 245      * the property cannot be maintained in a few situations like for
 246      * intermediate nodes of a commit block job.
 247      */
 248     BLK_PERM_CONSISTENT_READ    = 0x01,
 249
 250     /** This permission is required to change the visible disk contents. */
 251     BLK_PERM_WRITE              = 0x02,
 252
 253     /**
 254      * This permission (which is weaker than BLK_PERM_WRITE) is both enough and
 255      * required for writes to the block node when the caller promises that
 256      * the visible disk content doesn't change.
 257      *
 258      * As the BLK_PERM_WRITE permission is strictly stronger, either is
 259      * sufficient to perform an unchanging write.
 260      */
 261     BLK_PERM_WRITE_UNCHANGED    = 0x04,
 262
 263     /** This permission is required to change the size of a block node. */
 264     BLK_PERM_RESIZE             = 0x08,
 265
 266     /**
 267      * This permission is required to change the node that this BdrvChild
 268      * points to.
 269      */
 270     BLK_PERM_GRAPH_MOD          = 0x10,
 271
 272     BLK_PERM_ALL                = 0x1f,
 273
 274     DEFAULT_PERM_PASSTHROUGH    = BLK_PERM_CONSISTENT_READ
 275                                  | BLK_PERM_WRITE
 276                                  | BLK_PERM_WRITE_UNCHANGED
 277                                  | BLK_PERM_RESIZE,
 278
 279     DEFAULT_PERM_UNCHANGED      = BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH,
 280 };
 281
 282 char *bdrv_perm_names(uint64_t perm);
 283 uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm);
 284
 285 /* disk I/O throttling */
 286 void bdrv_init(void);
 287 void bdrv_init_with_whitelist(void);
 288 bool bdrv_uses_whitelist(void);
 289 int bdrv_is_whitelisted(BlockDriver *drv, bool read_only);
 290 BlockDriver *bdrv_find_protocol(const char *filename,
 291                                 bool allow_protocol_prefix,
 292                                 Error **errp);
 293 BlockDriver *bdrv_find_format(const char *format_name);
 294 int bdrv_create(BlockDriver *drv, const char* filename,
 295                 QemuOpts *opts, Error **errp);
 296 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp);
 297 BlockDriverState *bdrv_new(void);
 298 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
 299                  Error **errp);
 300 void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
 301                        Error **errp);
 302
 303 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough);
 304 int bdrv_parse_discard_flags(const char *mode, int *flags);
 305 BdrvChild *bdrv_open_child(const char *filename,
 306                            QDict *options, const char *bdref_key,
 307                            BlockDriverState* parent,
 308                            const BdrvChildRole *child_role,
 309                            bool allow_none, Error **errp);
 310 BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp);
 311 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
 312                          Error **errp);
 313 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
 314                            const char *bdref_key, Error **errp);
 315 BlockDriverState *bdrv_open(const char *filename, const char *reference,
 316                             QDict *options, int flags, Error **errp);
 317 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
 318                                        int flags, Error **errp);
 319 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
 320                                     BlockDriverState *bs, QDict *options,
 321                                     bool keep_old_opts);
 322 int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp);
 323 int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
 324                               Error **errp);
 325 int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
 326                         BlockReopenQueue *queue, Error **errp);
 327 void bdrv_reopen_commit(BDRVReopenState *reopen_state);
 328 void bdrv_reopen_abort(BDRVReopenState *reopen_state);
 329 int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
 330                        int bytes, BdrvRequestFlags flags);
 331 int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
 332 int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes);
 333 int bdrv_preadv(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
 334 int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes);
 335 int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
 336 int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
 337                      const void *buf, int count);
 338 /*
 339  * Efficiently zero a region of the disk image.  Note that this is a regular
 340  * I/O request like read or write and should have a reasonable size.  This
 341  * function is not suitable for zeroing the entire image in a single request
 342  * because it may allocate memory for the entire region.
 343  */
 344 int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
 345                                        int bytes, BdrvRequestFlags flags);
 346 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
 347     const char *backing_file);
 348 void bdrv_refresh_filename(BlockDriverState *bs);
 349
 350 int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact,
 351                                   PreallocMode prealloc, Error **errp);
 352 int bdrv_truncate(BdrvChild *child, int64_t offset, bool exact,
 353                   PreallocMode prealloc, Error **errp);
 354
 355 int64_t bdrv_nb_sectors(BlockDriverState *bs);
 356 int64_t bdrv_getlength(BlockDriverState *bs);
 357 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
 358 BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
 359                                BlockDriverState *in_bs, Error **errp);
 360 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
 361 void bdrv_refresh_limits(BlockDriverState *bs, Error **errp);
 362 int bdrv_commit(BlockDriverState *bs);
 363 int bdrv_change_backing_file(BlockDriverState *bs,
 364     const char *backing_file, const char *backing_fmt);
 365 void bdrv_register(BlockDriver *bdrv);
 366 int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
 367                            const char *backing_file_str);
 368 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
 369                                     BlockDriverState *bs);
 370 BlockDriverState *bdrv_find_base(BlockDriverState *bs);
 371 bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base,
 372                                   Error **errp);
 373 int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base,
 374                               Error **errp);
 375 void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base);
 376
 377
 378 typedef struct BdrvCheckResult {
 379     int corruptions;
 380     int leaks;
 381     int check_errors;
 382     int corruptions_fixed;
 383     int leaks_fixed;
 384     int64_t image_end_offset;
 385     BlockFragInfo bfi;
 386 } BdrvCheckResult;
 387
 388 typedef enum {
 389     BDRV_FIX_LEAKS    = 1,
 390     BDRV_FIX_ERRORS   = 2,
 391 } BdrvCheckMode;
 392
 393 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
 394
 395 /* The units of offset and total_work_size may be chosen arbitrarily by the
 396  * block driver; total_work_size may change during the course of the amendment
 397  * operation */
 398 typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
 399                                       int64_t total_work_size, void *opaque);
 400 int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
 401                        BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
 402                        Error **errp);
 403
 404 /* external snapshots */
 405 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
 406                                       BlockDriverState *candidate);
 407 bool bdrv_is_first_non_filter(BlockDriverState *candidate);
 408
 409 /* check if a named node can be replaced when doing drive-mirror */
 410 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
 411                                         const char *node_name, Error **errp);
 412
 413 /* async block I/O */
 414 void bdrv_aio_cancel(BlockAIOCB *acb);
 415 void bdrv_aio_cancel_async(BlockAIOCB *acb);
 416
 417 /* sg packet commands */
 418 int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf);
 419
 420 /* Invalidate any cached metadata used by image formats */
 421 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp);
 422 void bdrv_invalidate_cache_all(Error **errp);
 423 int bdrv_inactivate_all(void);
 424
 425 /* Ensure contents are flushed to disk.  */
 426 int bdrv_flush(BlockDriverState *bs);
 427 int coroutine_fn bdrv_co_flush(BlockDriverState *bs);
 428 int bdrv_flush_all(void);
 429 void bdrv_close_all(void);
 430 void bdrv_drain(BlockDriverState *bs);
 431 void coroutine_fn bdrv_co_drain(BlockDriverState *bs);
 432 void bdrv_drain_all_begin(void);
 433 void bdrv_drain_all_end(void);
 434 void bdrv_drain_all(void);
 435
 436 #define BDRV_POLL_WHILE(bs, cond) ({                       \
 437     BlockDriverState *bs_ = (bs);                          \
 438     AIO_WAIT_WHILE(bdrv_get_aio_context(bs_),              \
 439                    cond); })
 440
 441 int bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
 442 int bdrv_co_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
 443 int bdrv_has_zero_init_1(BlockDriverState *bs);
 444 int bdrv_has_zero_init(BlockDriverState *bs);
 445 int bdrv_has_zero_init_truncate(BlockDriverState *bs);
 446 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs);
 447 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
 448 int bdrv_block_status(BlockDriverState *bs, int64_t offset,
 449                       int64_t bytes, int64_t *pnum, int64_t *map,
 450                       BlockDriverState **file);
 451 int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
 452                             int64_t offset, int64_t bytes, int64_t *pnum,
 453                             int64_t *map, BlockDriverState **file);
 454 int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
 455                       int64_t *pnum);
 456 int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
 457                             bool include_base, int64_t offset, int64_t bytes,
 458                             int64_t *pnum);
 459
 460 bool bdrv_is_read_only(BlockDriverState *bs);
 461 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
 462                            bool ignore_allow_rdw, Error **errp);
 463 int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg,
 464                               Error **errp);
 465 bool bdrv_is_writable(BlockDriverState *bs);
 466 bool bdrv_is_sg(BlockDriverState *bs);
 467 bool bdrv_is_inserted(BlockDriverState *bs);
 468 void bdrv_lock_medium(BlockDriverState *bs, bool locked);
 469 void bdrv_eject(BlockDriverState *bs, bool eject_flag);
 470 const char *bdrv_get_format_name(BlockDriverState *bs);
 471 BlockDriverState *bdrv_find_node(const char *node_name);
 472 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp);
 473 XDbgBlockGraph *bdrv_get_xdbg_block_graph(Error **errp);
 474 BlockDriverState *bdrv_lookup_bs(const char *device,
 475                                  const char *node_name,
 476                                  Error **errp);
 477 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
 478 BlockDriverState *bdrv_next_node(BlockDriverState *bs);
 479 BlockDriverState *bdrv_next_all_states(BlockDriverState *bs);
 480
 481 typedef struct BdrvNextIterator {
 482     enum {
 483         BDRV_NEXT_BACKEND_ROOTS,
 484         BDRV_NEXT_MONITOR_OWNED,
 485     } phase;
 486     BlockBackend *blk;
 487     BlockDriverState *bs;
 488 } BdrvNextIterator;
 489
 490 BlockDriverState *bdrv_first(BdrvNextIterator *it);
 491 BlockDriverState *bdrv_next(BdrvNextIterator *it);
 492 void bdrv_next_cleanup(BdrvNextIterator *it);
 493
 494 BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs);
 495 bool bdrv_is_encrypted(BlockDriverState *bs);
 496 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
 497                          void *opaque, bool read_only);
 498 const char *bdrv_get_node_name(const BlockDriverState *bs);
 499 const char *bdrv_get_device_name(const BlockDriverState *bs);
 500 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
 501 int bdrv_get_flags(BlockDriverState *bs);
 502 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
 503 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs,
 504                                           Error **errp);
 505 BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs);
 506 void bdrv_round_to_clusters(BlockDriverState *bs,
 507                             int64_t offset, int64_t bytes,
 508                             int64_t *cluster_offset,
 509                             int64_t *cluster_bytes);
 510
 511 void bdrv_get_backing_filename(BlockDriverState *bs,
 512                                char *filename, int filename_size);
 513 char *bdrv_get_full_backing_filename(BlockDriverState *bs, Error **errp);
 514 char *bdrv_get_full_backing_filename_from_filename(const char *backed,
 515                                                    const char *backing,
 516                                                    Error **errp);
 517 char *bdrv_dirname(BlockDriverState *bs, Error **errp);
 518
 519 int path_has_protocol(const char *path);
 520 int path_is_absolute(const char *path);
 521 char *path_combine(const char *base_path, const char *filename);
 522
 523 int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 524 int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 525 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
 526                       int64_t pos, int size);
 527
 528 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
 529                       int64_t pos, int size);
 530
 531 void bdrv_img_create(const char *filename, const char *fmt,
 532                      const char *base_filename, const char *base_fmt,
 533                      char *options, uint64_t img_size, int flags,
 534                      bool quiet, Error **errp);
 535
 536 /* Returns the alignment in bytes that is required so that no bounce buffer
 537  * is required throughout the stack */
 538 size_t bdrv_min_mem_align(BlockDriverState *bs);
 539 /* Returns optimal alignment in bytes for bounce buffer */
 540 size_t bdrv_opt_mem_align(BlockDriverState *bs);
 541 void *qemu_blockalign(BlockDriverState *bs, size_t size);
 542 void *qemu_blockalign0(BlockDriverState *bs, size_t size);
 543 void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
 544 void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
 545 bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);
 546
 547 void bdrv_enable_copy_on_read(BlockDriverState *bs);
 548 void bdrv_disable_copy_on_read(BlockDriverState *bs);
 549
 550 void bdrv_ref(BlockDriverState *bs);
 551 void bdrv_unref(BlockDriverState *bs);
 552 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child);
 553 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
 554                              BlockDriverState *child_bs,
 555                              const char *child_name,
 556                              const BdrvChildRole *child_role,
 557                              Error **errp);
 558
 559 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
 560 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);
 561 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason);
 562 void bdrv_op_block_all(BlockDriverState *bs, Error *reason);
 563 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason);
 564 bool bdrv_op_blocker_is_empty(BlockDriverState *bs);
 565
 566 #define BLKDBG_EVENT(child, evt) \
 567     do { \
 568         if (child) { \
 569             bdrv_debug_event(child->bs, evt); \
 570         } \
 571     } while (0)
 572
 573 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
 574
 575 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
 576                            const char *tag);
 577 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag);
 578 int bdrv_debug_resume(BlockDriverState *bs, const char *tag);
 579 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag);
 580
 581 /**
 582  * bdrv_get_aio_context:
 583  *
 584  * Returns: the currently bound #AioContext
 585  */
 586 AioContext *bdrv_get_aio_context(BlockDriverState *bs);
 587
 588 /**
 589  * Transfer control to @co in the aio context of @bs
 590  */
 591 void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co);
 592
 593 void bdrv_set_aio_context_ignore(BlockDriverState *bs,
 594                                  AioContext *new_context, GSList **ignore);
 595 int bdrv_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
 596                              Error **errp);
 597 int bdrv_child_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
 598                                    BdrvChild *ignore_child, Error **errp);
 599 bool bdrv_child_can_set_aio_context(BdrvChild *c, AioContext *ctx,
 600                                     GSList **ignore, Error **errp);
 601 bool bdrv_can_set_aio_context(BlockDriverState *bs, AioContext *ctx,
 602                               GSList **ignore, Error **errp);
 603 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
 604 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
 605
 606 void bdrv_io_plug(BlockDriverState *bs);
 607 void bdrv_io_unplug(BlockDriverState *bs);
 608
 609 /**
 610  * bdrv_parent_drained_begin_single:
 611  *
 612  * Begin a quiesced section for the parent of @c. If @poll is true, wait for
 613  * any pending activity to cease.
 614  */
 615 void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll);
 616
 617 /**
 618  * bdrv_parent_drained_end_single:
 619  *
 620  * End a quiesced section for the parent of @c.
 621  *
 622  * This polls @bs's AioContext until all scheduled sub-drained_ends
 623  * have settled, which may result in graph changes.
 624  */
 625 void bdrv_parent_drained_end_single(BdrvChild *c);
 626
 627 /**
 628  * bdrv_drain_poll:
 629  *
 630  * Poll for pending requests in @bs, its parents (except for @ignore_parent),
 631  * and if @recursive is true its children as well (used for subtree drain).
 632  *
 633  * If @ignore_bds_parents is true, parents that are BlockDriverStates must
 634  * ignore the drain request because they will be drained separately (used for
 635  * drain_all).
 636  *
 637  * This is part of bdrv_drained_begin.
 638  */
 639 bool bdrv_drain_poll(BlockDriverState *bs, bool recursive,
 640                      BdrvChild *ignore_parent, bool ignore_bds_parents);
 641
 642 /**
 643  * bdrv_drained_begin:
 644  *
 645  * Begin a quiesced section for exclusive access to the BDS, by disabling
 646  * external request sources including NBD server and device model. Note that
 647  * this doesn't block timers or coroutines from submitting more requests, which
 648  * means block_job_pause is still necessary.
 649  *
 650  * This function can be recursive.
 651  */
 652 void bdrv_drained_begin(BlockDriverState *bs);
 653
 654 /**
 655  * bdrv_do_drained_begin_quiesce:
 656  *
 657  * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already
 658  * running requests to complete.
 659  */
 660 void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,
 661                                    BdrvChild *parent, bool ignore_bds_parents);
 662
 663 /**
 664  * Like bdrv_drained_begin, but recursively begins a quiesced section for
 665  * exclusive access to all child nodes as well.
 666  */
 667 void bdrv_subtree_drained_begin(BlockDriverState *bs);
 668
 669 /**
 670  * bdrv_drained_end:
 671  *
 672  * End a quiescent section started by bdrv_drained_begin().
 673  *
 674  * This polls @bs's AioContext until all scheduled sub-drained_ends
 675  * have settled.  On one hand, that may result in graph changes.  On
 676  * the other, this requires that the caller either runs in the main
 677  * loop; or that all involved nodes (@bs and all of its parents) are
 678  * in the caller's AioContext.
 679  */
 680 void bdrv_drained_end(BlockDriverState *bs);
 681
 682 /**
 683  * bdrv_drained_end_no_poll:
 684  *
 685  * Same as bdrv_drained_end(), but do not poll for the subgraph to
 686  * actually become unquiesced.  Therefore, no graph changes will occur
 687  * with this function.
 688  *
 689  * *drained_end_counter is incremented for every background operation
 690  * that is scheduled, and will be decremented for every operation once
 691  * it settles.  The caller must poll until it reaches 0.  The counter
 692  * should be accessed using atomic operations only.
 693  */
 694 void bdrv_drained_end_no_poll(BlockDriverState *bs, int *drained_end_counter);
 695
 696 /**
 697  * End a quiescent section started by bdrv_subtree_drained_begin().
 698  */
 699 void bdrv_subtree_drained_end(BlockDriverState *bs);
 700
 701 void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
 702                     Error **errp);
 703 void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
 704
 705 bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
 706                                      uint32_t granularity, Error **errp);
 707 /**
 708  *
 709  * bdrv_register_buf/bdrv_unregister_buf:
 710  *
 711  * Register/unregister a buffer for I/O. For example, VFIO drivers are
 712  * interested to know the memory areas that would later be used for I/O, so
 713  * that they can prepare IOMMU mapping etc., to get better performance.
 714  */
 715 void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size);
 716 void bdrv_unregister_buf(BlockDriverState *bs, void *host);
 717
 718 /**
 719  *
 720  * bdrv_co_copy_range:
 721  *
 722  * Do offloaded copy between two children. If the operation is not implemented
 723  * by the driver, or if the backend storage doesn't support it, a negative
 724  * error code will be returned.
 725  *
 726  * Note: block layer doesn't emulate or fallback to a bounce buffer approach
 727  * because usually the caller shouldn't attempt offloaded copy any more (e.g.
 728  * calling copy_file_range(2)) after the first error, thus it should fall back
 729  * to a read+write path in the caller level.
 730  *
 731  * @src: Source child to copy data from
 732  * @src_offset: offset in @src image to read data
 733  * @dst: Destination child to copy data to
 734  * @dst_offset: offset in @dst image to write data
 735  * @bytes: number of bytes to copy
 736  * @flags: request flags. Supported flags:
 737  *         BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero
 738  *                               write on @dst as if bdrv_co_pwrite_zeroes is
 739  *                               called. Used to simplify caller code, or
 740  *                               during BlockDriver.bdrv_co_copy_range_from()
 741  *                               recursion.
 742  *         BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping
 743  *                                   requests currently in flight.
 744  *
 745  * Returns: 0 if succeeded; negative error code if failed.
 746  **/
 747 int coroutine_fn bdrv_co_copy_range(BdrvChild *src, uint64_t src_offset,
 748                                     BdrvChild *dst, uint64_t dst_offset,
 749                                     uint64_t bytes, BdrvRequestFlags read_flags,
 750                                     BdrvRequestFlags write_flags);
 751 #endif