qemu/include/block/block.h
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   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 */
  14typedef struct BlockDriver BlockDriver;
  15typedef struct BdrvChild BdrvChild;
  16typedef struct BdrvChildRole BdrvChildRole;
  17
  18typedef 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
  35typedef 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
  42typedef 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
 100typedef struct BlockSizes {
 101    uint32_t phys;
 102    uint32_t log;
 103} BlockSizes;
 104
 105typedef 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
 198typedef QTAILQ_HEAD(BlockReopenQueue, BlockReopenQueueEntry) BlockReopenQueue;
 199
 200typedef 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 */
 216typedef 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 */
 237enum {
 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
 282char *bdrv_perm_names(uint64_t perm);
 283
 284/* disk I/O throttling */
 285void bdrv_init(void);
 286void bdrv_init_with_whitelist(void);
 287bool bdrv_uses_whitelist(void);
 288int bdrv_is_whitelisted(BlockDriver *drv, bool read_only);
 289BlockDriver *bdrv_find_protocol(const char *filename,
 290                                bool allow_protocol_prefix,
 291                                Error **errp);
 292BlockDriver *bdrv_find_format(const char *format_name);
 293int bdrv_create(BlockDriver *drv, const char* filename,
 294                QemuOpts *opts, Error **errp);
 295int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp);
 296BlockDriverState *bdrv_new(void);
 297void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
 298                 Error **errp);
 299void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
 300                       Error **errp);
 301
 302int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough);
 303int bdrv_parse_discard_flags(const char *mode, int *flags);
 304BdrvChild *bdrv_open_child(const char *filename,
 305                           QDict *options, const char *bdref_key,
 306                           BlockDriverState* parent,
 307                           const BdrvChildRole *child_role,
 308                           bool allow_none, Error **errp);
 309BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp);
 310void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
 311                         Error **errp);
 312int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
 313                           const char *bdref_key, Error **errp);
 314BlockDriverState *bdrv_open(const char *filename, const char *reference,
 315                            QDict *options, int flags, Error **errp);
 316BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
 317                                       int flags, Error **errp);
 318BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
 319                                    BlockDriverState *bs, QDict *options,
 320                                    bool keep_old_opts);
 321int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp);
 322int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
 323                              Error **errp);
 324int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
 325                        BlockReopenQueue *queue, Error **errp);
 326void bdrv_reopen_commit(BDRVReopenState *reopen_state);
 327void bdrv_reopen_abort(BDRVReopenState *reopen_state);
 328int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
 329                       int bytes, BdrvRequestFlags flags);
 330int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
 331int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes);
 332int bdrv_preadv(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
 333int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes);
 334int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
 335int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
 336                     const void *buf, int count);
 337/*
 338 * Efficiently zero a region of the disk image.  Note that this is a regular
 339 * I/O request like read or write and should have a reasonable size.  This
 340 * function is not suitable for zeroing the entire image in a single request
 341 * because it may allocate memory for the entire region.
 342 */
 343int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
 344                                       int bytes, BdrvRequestFlags flags);
 345BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
 346    const char *backing_file);
 347void bdrv_refresh_filename(BlockDriverState *bs);
 348
 349int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact,
 350                                  PreallocMode prealloc, Error **errp);
 351int bdrv_truncate(BdrvChild *child, int64_t offset, bool exact,
 352                  PreallocMode prealloc, Error **errp);
 353
 354int64_t bdrv_nb_sectors(BlockDriverState *bs);
 355int64_t bdrv_getlength(BlockDriverState *bs);
 356int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
 357BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
 358                               BlockDriverState *in_bs, Error **errp);
 359void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
 360void bdrv_refresh_limits(BlockDriverState *bs, Error **errp);
 361int bdrv_commit(BlockDriverState *bs);
 362int bdrv_change_backing_file(BlockDriverState *bs,
 363    const char *backing_file, const char *backing_fmt);
 364void bdrv_register(BlockDriver *bdrv);
 365int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
 366                           const char *backing_file_str);
 367BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
 368                                    BlockDriverState *bs);
 369BlockDriverState *bdrv_find_base(BlockDriverState *bs);
 370bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base,
 371                                  Error **errp);
 372int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base,
 373                              Error **errp);
 374void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base);
 375
 376
 377typedef struct BdrvCheckResult {
 378    int corruptions;
 379    int leaks;
 380    int check_errors;
 381    int corruptions_fixed;
 382    int leaks_fixed;
 383    int64_t image_end_offset;
 384    BlockFragInfo bfi;
 385} BdrvCheckResult;
 386
 387typedef enum {
 388    BDRV_FIX_LEAKS    = 1,
 389    BDRV_FIX_ERRORS   = 2,
 390} BdrvCheckMode;
 391
 392int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
 393
 394/* The units of offset and total_work_size may be chosen arbitrarily by the
 395 * block driver; total_work_size may change during the course of the amendment
 396 * operation */
 397typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
 398                                      int64_t total_work_size, void *opaque);
 399int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
 400                       BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
 401                       Error **errp);
 402
 403/* external snapshots */
 404bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
 405                                      BlockDriverState *candidate);
 406bool bdrv_is_first_non_filter(BlockDriverState *candidate);
 407
 408/* check if a named node can be replaced when doing drive-mirror */
 409BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
 410                                        const char *node_name, Error **errp);
 411
 412/* async block I/O */
 413void bdrv_aio_cancel(BlockAIOCB *acb);
 414void bdrv_aio_cancel_async(BlockAIOCB *acb);
 415
 416/* sg packet commands */
 417int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf);
 418
 419/* Invalidate any cached metadata used by image formats */
 420void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp);
 421void bdrv_invalidate_cache_all(Error **errp);
 422int bdrv_inactivate_all(void);
 423
 424/* Ensure contents are flushed to disk.  */
 425int bdrv_flush(BlockDriverState *bs);
 426int coroutine_fn bdrv_co_flush(BlockDriverState *bs);
 427int bdrv_flush_all(void);
 428void bdrv_close_all(void);
 429void bdrv_drain(BlockDriverState *bs);
 430void coroutine_fn bdrv_co_drain(BlockDriverState *bs);
 431void bdrv_drain_all_begin(void);
 432void bdrv_drain_all_end(void);
 433void bdrv_drain_all(void);
 434
 435#define BDRV_POLL_WHILE(bs, cond) ({                       \
 436    BlockDriverState *bs_ = (bs);                          \
 437    AIO_WAIT_WHILE(bdrv_get_aio_context(bs_),              \
 438                   cond); })
 439
 440int bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
 441int bdrv_co_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
 442int bdrv_has_zero_init_1(BlockDriverState *bs);
 443int bdrv_has_zero_init(BlockDriverState *bs);
 444int bdrv_has_zero_init_truncate(BlockDriverState *bs);
 445bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs);
 446bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
 447int bdrv_block_status(BlockDriverState *bs, int64_t offset,
 448                      int64_t bytes, int64_t *pnum, int64_t *map,
 449                      BlockDriverState **file);
 450int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
 451                            int64_t offset, int64_t bytes, int64_t *pnum,
 452                            int64_t *map, BlockDriverState **file);
 453int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
 454                      int64_t *pnum);
 455int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
 456                            bool include_base, int64_t offset, int64_t bytes,
 457                            int64_t *pnum);
 458
 459bool bdrv_is_read_only(BlockDriverState *bs);
 460int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
 461                           bool ignore_allow_rdw, Error **errp);
 462int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg,
 463                              Error **errp);
 464bool bdrv_is_writable(BlockDriverState *bs);
 465bool bdrv_is_sg(BlockDriverState *bs);
 466bool bdrv_is_inserted(BlockDriverState *bs);
 467void bdrv_lock_medium(BlockDriverState *bs, bool locked);
 468void bdrv_eject(BlockDriverState *bs, bool eject_flag);
 469const char *bdrv_get_format_name(BlockDriverState *bs);
 470BlockDriverState *bdrv_find_node(const char *node_name);
 471BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp);
 472XDbgBlockGraph *bdrv_get_xdbg_block_graph(Error **errp);
 473BlockDriverState *bdrv_lookup_bs(const char *device,
 474                                 const char *node_name,
 475                                 Error **errp);
 476bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
 477BlockDriverState *bdrv_next_node(BlockDriverState *bs);
 478BlockDriverState *bdrv_next_all_states(BlockDriverState *bs);
 479
 480typedef struct BdrvNextIterator {
 481    enum {
 482        BDRV_NEXT_BACKEND_ROOTS,
 483        BDRV_NEXT_MONITOR_OWNED,
 484    } phase;
 485    BlockBackend *blk;
 486    BlockDriverState *bs;
 487} BdrvNextIterator;
 488
 489BlockDriverState *bdrv_first(BdrvNextIterator *it);
 490BlockDriverState *bdrv_next(BdrvNextIterator *it);
 491void bdrv_next_cleanup(BdrvNextIterator *it);
 492
 493BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs);
 494bool bdrv_is_encrypted(BlockDriverState *bs);
 495void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
 496                         void *opaque, bool read_only);
 497const char *bdrv_get_node_name(const BlockDriverState *bs);
 498const char *bdrv_get_device_name(const BlockDriverState *bs);
 499const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
 500int bdrv_get_flags(BlockDriverState *bs);
 501int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
 502ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs,
 503                                          Error **errp);
 504BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs);
 505void bdrv_round_to_clusters(BlockDriverState *bs,
 506                            int64_t offset, int64_t bytes,
 507                            int64_t *cluster_offset,
 508                            int64_t *cluster_bytes);
 509
 510void bdrv_get_backing_filename(BlockDriverState *bs,
 511                               char *filename, int filename_size);
 512char *bdrv_get_full_backing_filename(BlockDriverState *bs, Error **errp);
 513char *bdrv_get_full_backing_filename_from_filename(const char *backed,
 514                                                   const char *backing,
 515                                                   Error **errp);
 516char *bdrv_dirname(BlockDriverState *bs, Error **errp);
 517
 518int path_has_protocol(const char *path);
 519int path_is_absolute(const char *path);
 520char *path_combine(const char *base_path, const char *filename);
 521
 522int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 523int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 524int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
 525                      int64_t pos, int size);
 526
 527int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
 528                      int64_t pos, int size);
 529
 530void bdrv_img_create(const char *filename, const char *fmt,
 531                     const char *base_filename, const char *base_fmt,
 532                     char *options, uint64_t img_size, int flags,
 533                     bool quiet, Error **errp);
 534
 535/* Returns the alignment in bytes that is required so that no bounce buffer
 536 * is required throughout the stack */
 537size_t bdrv_min_mem_align(BlockDriverState *bs);
 538/* Returns optimal alignment in bytes for bounce buffer */
 539size_t bdrv_opt_mem_align(BlockDriverState *bs);
 540void *qemu_blockalign(BlockDriverState *bs, size_t size);
 541void *qemu_blockalign0(BlockDriverState *bs, size_t size);
 542void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
 543void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
 544bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);
 545
 546void bdrv_enable_copy_on_read(BlockDriverState *bs);
 547void bdrv_disable_copy_on_read(BlockDriverState *bs);
 548
 549void bdrv_ref(BlockDriverState *bs);
 550void bdrv_unref(BlockDriverState *bs);
 551void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child);
 552BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
 553                             BlockDriverState *child_bs,
 554                             const char *child_name,
 555                             const BdrvChildRole *child_role,
 556                             Error **errp);
 557
 558bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
 559void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);
 560void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason);
 561void bdrv_op_block_all(BlockDriverState *bs, Error *reason);
 562void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason);
 563bool bdrv_op_blocker_is_empty(BlockDriverState *bs);
 564
 565#define BLKDBG_EVENT(child, evt) \
 566    do { \
 567        if (child) { \
 568            bdrv_debug_event(child->bs, evt); \
 569        } \
 570    } while (0)
 571
 572void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
 573
 574int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
 575                           const char *tag);
 576int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag);
 577int bdrv_debug_resume(BlockDriverState *bs, const char *tag);
 578bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag);
 579
 580/**
 581 * bdrv_get_aio_context:
 582 *
 583 * Returns: the currently bound #AioContext
 584 */
 585AioContext *bdrv_get_aio_context(BlockDriverState *bs);
 586
 587/**
 588 * Transfer control to @co in the aio context of @bs
 589 */
 590void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co);
 591
 592void bdrv_set_aio_context_ignore(BlockDriverState *bs,
 593                                 AioContext *new_context, GSList **ignore);
 594int bdrv_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
 595                             Error **errp);
 596int bdrv_child_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
 597                                   BdrvChild *ignore_child, Error **errp);
 598bool bdrv_child_can_set_aio_context(BdrvChild *c, AioContext *ctx,
 599                                    GSList **ignore, Error **errp);
 600bool bdrv_can_set_aio_context(BlockDriverState *bs, AioContext *ctx,
 601                              GSList **ignore, Error **errp);
 602int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
 603int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
 604
 605void bdrv_io_plug(BlockDriverState *bs);
 606void bdrv_io_unplug(BlockDriverState *bs);
 607
 608/**
 609 * bdrv_parent_drained_begin_single:
 610 *
 611 * Begin a quiesced section for the parent of @c. If @poll is true, wait for
 612 * any pending activity to cease.
 613 */
 614void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll);
 615
 616/**
 617 * bdrv_parent_drained_end_single:
 618 *
 619 * End a quiesced section for the parent of @c.
 620 *
 621 * This polls @bs's AioContext until all scheduled sub-drained_ends
 622 * have settled, which may result in graph changes.
 623 */
 624void bdrv_parent_drained_end_single(BdrvChild *c);
 625
 626/**
 627 * bdrv_drain_poll:
 628 *
 629 * Poll for pending requests in @bs, its parents (except for @ignore_parent),
 630 * and if @recursive is true its children as well (used for subtree drain).
 631 *
 632 * If @ignore_bds_parents is true, parents that are BlockDriverStates must
 633 * ignore the drain request because they will be drained separately (used for
 634 * drain_all).
 635 *
 636 * This is part of bdrv_drained_begin.
 637 */
 638bool bdrv_drain_poll(BlockDriverState *bs, bool recursive,
 639                     BdrvChild *ignore_parent, bool ignore_bds_parents);
 640
 641/**
 642 * bdrv_drained_begin:
 643 *
 644 * Begin a quiesced section for exclusive access to the BDS, by disabling
 645 * external request sources including NBD server and device model. Note that
 646 * this doesn't block timers or coroutines from submitting more requests, which
 647 * means block_job_pause is still necessary.
 648 *
 649 * This function can be recursive.
 650 */
 651void bdrv_drained_begin(BlockDriverState *bs);
 652
 653/**
 654 * bdrv_do_drained_begin_quiesce:
 655 *
 656 * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already
 657 * running requests to complete.
 658 */
 659void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,
 660                                   BdrvChild *parent, bool ignore_bds_parents);
 661
 662/**
 663 * Like bdrv_drained_begin, but recursively begins a quiesced section for
 664 * exclusive access to all child nodes as well.
 665 */
 666void bdrv_subtree_drained_begin(BlockDriverState *bs);
 667
 668/**
 669 * bdrv_drained_end:
 670 *
 671 * End a quiescent section started by bdrv_drained_begin().
 672 *
 673 * This polls @bs's AioContext until all scheduled sub-drained_ends
 674 * have settled.  On one hand, that may result in graph changes.  On
 675 * the other, this requires that the caller either runs in the main
 676 * loop; or that all involved nodes (@bs and all of its parents) are
 677 * in the caller's AioContext.
 678 */
 679void bdrv_drained_end(BlockDriverState *bs);
 680
 681/**
 682 * bdrv_drained_end_no_poll:
 683 *
 684 * Same as bdrv_drained_end(), but do not poll for the subgraph to
 685 * actually become unquiesced.  Therefore, no graph changes will occur
 686 * with this function.
 687 *
 688 * *drained_end_counter is incremented for every background operation
 689 * that is scheduled, and will be decremented for every operation once
 690 * it settles.  The caller must poll until it reaches 0.  The counter
 691 * should be accessed using atomic operations only.
 692 */
 693void bdrv_drained_end_no_poll(BlockDriverState *bs, int *drained_end_counter);
 694
 695/**
 696 * End a quiescent section started by bdrv_subtree_drained_begin().
 697 */
 698void bdrv_subtree_drained_end(BlockDriverState *bs);
 699
 700void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
 701                    Error **errp);
 702void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
 703
 704bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
 705                                     uint32_t granularity, Error **errp);
 706/**
 707 *
 708 * bdrv_register_buf/bdrv_unregister_buf:
 709 *
 710 * Register/unregister a buffer for I/O. For example, VFIO drivers are
 711 * interested to know the memory areas that would later be used for I/O, so
 712 * that they can prepare IOMMU mapping etc., to get better performance.
 713 */
 714void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size);
 715void bdrv_unregister_buf(BlockDriverState *bs, void *host);
 716
 717/**
 718 *
 719 * bdrv_co_copy_range:
 720 *
 721 * Do offloaded copy between two children. If the operation is not implemented
 722 * by the driver, or if the backend storage doesn't support it, a negative
 723 * error code will be returned.
 724 *
 725 * Note: block layer doesn't emulate or fallback to a bounce buffer approach
 726 * because usually the caller shouldn't attempt offloaded copy any more (e.g.
 727 * calling copy_file_range(2)) after the first error, thus it should fall back
 728 * to a read+write path in the caller level.
 729 *
 730 * @src: Source child to copy data from
 731 * @src_offset: offset in @src image to read data
 732 * @dst: Destination child to copy data to
 733 * @dst_offset: offset in @dst image to write data
 734 * @bytes: number of bytes to copy
 735 * @flags: request flags. Supported flags:
 736 *         BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero
 737 *                               write on @dst as if bdrv_co_pwrite_zeroes is
 738 *                               called. Used to simplify caller code, or
 739 *                               during BlockDriver.bdrv_co_copy_range_from()
 740 *                               recursion.
 741 *         BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping
 742 *                                   requests currently in flight.
 743 *
 744 * Returns: 0 if succeeded; negative error code if failed.
 745 **/
 746int coroutine_fn bdrv_co_copy_range(BdrvChild *src, uint64_t src_offset,
 747                                    BdrvChild *dst, uint64_t dst_offset,
 748                                    uint64_t bytes, BdrvRequestFlags read_flags,
 749                                    BdrvRequestFlags write_flags);
 750#endif
 751