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 "qapi/qapi-types-block-core.h"
   6#include "block/aio-wait.h"
   7#include "qemu/iov.h"
   8#include "qemu/coroutine.h"
   9#include "block/accounting.h"
  10#include "block/dirty-bitmap.h"
  11#include "block/blockjob.h"
  12#include "qemu/hbitmap.h"
  13
  14/* block.c */
  15typedef struct BlockDriver BlockDriver;
  16typedef struct BdrvChild BdrvChild;
  17typedef struct BdrvChildRole BdrvChildRole;
  18
  19typedef struct BlockDriverInfo {
  20    /* in bytes, 0 if irrelevant */
  21    int cluster_size;
  22    /* offset at which the VM state can be saved (0 if not possible) */
  23    int64_t vm_state_offset;
  24    bool is_dirty;
  25    /*
  26     * True if unallocated blocks read back as zeroes. This is equivalent
  27     * to the LBPRZ flag in the SCSI logical block provisioning page.
  28     */
  29    bool unallocated_blocks_are_zero;
  30    /*
  31     * True if this block driver only supports compressed writes
  32     */
  33    bool needs_compressed_writes;
  34} BlockDriverInfo;
  35
  36typedef struct BlockFragInfo {
  37    uint64_t allocated_clusters;
  38    uint64_t total_clusters;
  39    uint64_t fragmented_clusters;
  40    uint64_t compressed_clusters;
  41} BlockFragInfo;
  42
  43typedef enum {
  44    BDRV_REQ_COPY_ON_READ       = 0x1,
  45    BDRV_REQ_ZERO_WRITE         = 0x2,
  46
  47    /*
  48     * The BDRV_REQ_MAY_UNMAP flag is used in write_zeroes requests to indicate
  49     * that the block driver should unmap (discard) blocks if it is guaranteed
  50     * that the result will read back as zeroes. The flag is only passed to the
  51     * driver if the block device is opened with BDRV_O_UNMAP.
  52     */
  53    BDRV_REQ_MAY_UNMAP          = 0x4,
  54
  55    /*
  56     * The BDRV_REQ_NO_SERIALISING flag is only valid for reads and means that
  57     * we don't want wait_serialising_requests() during the read operation.
  58     *
  59     * This flag is used for backup copy-on-write operations, when we need to
  60     * read old data before write (write notifier triggered). It is okay since
  61     * we already waited for other serializing requests in the initiating write
  62     * (see bdrv_aligned_pwritev), and it is necessary if the initiating write
  63     * is already serializing (without the flag, the read would deadlock
  64     * waiting for the serialising write to complete).
  65     */
  66    BDRV_REQ_NO_SERIALISING     = 0x8,
  67    BDRV_REQ_FUA                = 0x10,
  68    BDRV_REQ_WRITE_COMPRESSED   = 0x20,
  69
  70    /* Signifies that this write request will not change the visible disk
  71     * content. */
  72    BDRV_REQ_WRITE_UNCHANGED    = 0x40,
  73
  74    /*
  75     * BDRV_REQ_SERIALISING forces request serialisation for writes.
  76     * It is used to ensure that writes to the backing file of a backup process
  77     * target cannot race with a read of the backup target that defers to the
  78     * backing file.
  79     *
  80     * Note, that BDRV_REQ_SERIALISING is _not_ opposite in meaning to
  81     * BDRV_REQ_NO_SERIALISING. A more descriptive name for the latter might be
  82     * _DO_NOT_WAIT_FOR_SERIALISING, except that is too long.
  83     */
  84    BDRV_REQ_SERIALISING        = 0x80,
  85
  86    /* Execute the request only if the operation can be offloaded or otherwise
  87     * be executed efficiently, but return an error instead of using a slow
  88     * fallback. */
  89    BDRV_REQ_NO_FALLBACK        = 0x100,
  90
  91    /* Mask of valid flags */
  92    BDRV_REQ_MASK               = 0x1ff,
  93} BdrvRequestFlags;
  94
  95typedef struct BlockSizes {
  96    uint32_t phys;
  97    uint32_t log;
  98} BlockSizes;
  99
 100typedef struct HDGeometry {
 101    uint32_t heads;
 102    uint32_t sectors;
 103    uint32_t cylinders;
 104} HDGeometry;
 105
 106#define BDRV_O_RDWR        0x0002
 107#define BDRV_O_RESIZE      0x0004 /* request permission for resizing the node */
 108#define BDRV_O_SNAPSHOT    0x0008 /* open the file read only and save writes in a snapshot */
 109#define BDRV_O_TEMPORARY   0x0010 /* delete the file after use */
 110#define BDRV_O_NOCACHE     0x0020 /* do not use the host page cache */
 111#define BDRV_O_NATIVE_AIO  0x0080 /* use native AIO instead of the thread pool */
 112#define BDRV_O_NO_BACKING  0x0100 /* don't open the backing file */
 113#define BDRV_O_NO_FLUSH    0x0200 /* disable flushing on this disk */
 114#define BDRV_O_COPY_ON_READ 0x0400 /* copy read backing sectors into image */
 115#define BDRV_O_INACTIVE    0x0800  /* consistency hint for migration handoff */
 116#define BDRV_O_CHECK       0x1000  /* open solely for consistency check */
 117#define BDRV_O_ALLOW_RDWR  0x2000  /* allow reopen to change from r/o to r/w */
 118#define BDRV_O_UNMAP       0x4000  /* execute guest UNMAP/TRIM operations */
 119#define BDRV_O_PROTOCOL    0x8000  /* if no block driver is explicitly given:
 120                                      select an appropriate protocol driver,
 121                                      ignoring the format layer */
 122#define BDRV_O_NO_IO       0x10000 /* don't initialize for I/O */
 123#define BDRV_O_AUTO_RDONLY 0x20000 /* degrade to read-only if opening read-write fails */
 124
 125#define BDRV_O_CACHE_MASK  (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH)
 126
 127
 128/* Option names of options parsed by the block layer */
 129
 130#define BDRV_OPT_CACHE_WB       "cache.writeback"
 131#define BDRV_OPT_CACHE_DIRECT   "cache.direct"
 132#define BDRV_OPT_CACHE_NO_FLUSH "cache.no-flush"
 133#define BDRV_OPT_READ_ONLY      "read-only"
 134#define BDRV_OPT_AUTO_READ_ONLY "auto-read-only"
 135#define BDRV_OPT_DISCARD        "discard"
 136#define BDRV_OPT_FORCE_SHARE    "force-share"
 137
 138
 139#define BDRV_SECTOR_BITS   9
 140#define BDRV_SECTOR_SIZE   (1ULL << BDRV_SECTOR_BITS)
 141#define BDRV_SECTOR_MASK   ~(BDRV_SECTOR_SIZE - 1)
 142
 143#define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \
 144                                     INT_MAX >> BDRV_SECTOR_BITS)
 145#define BDRV_REQUEST_MAX_BYTES (BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS)
 146
 147/*
 148 * Allocation status flags for bdrv_block_status() and friends.
 149 *
 150 * Public flags:
 151 * BDRV_BLOCK_DATA: allocation for data at offset is tied to this layer
 152 * BDRV_BLOCK_ZERO: offset reads as zero
 153 * BDRV_BLOCK_OFFSET_VALID: an associated offset exists for accessing raw data
 154 * BDRV_BLOCK_ALLOCATED: the content of the block is determined by this
 155 *                       layer rather than any backing, set by block layer
 156 * BDRV_BLOCK_EOF: the returned pnum covers through end of file for this
 157 *                 layer, set by block layer
 158 *
 159 * Internal flags:
 160 * BDRV_BLOCK_RAW: for use by passthrough drivers, such as raw, to request
 161 *                 that the block layer recompute the answer from the returned
 162 *                 BDS; must be accompanied by just BDRV_BLOCK_OFFSET_VALID.
 163 * BDRV_BLOCK_RECURSE: request that the block layer will recursively search for
 164 *                     zeroes in file child of current block node inside
 165 *                     returned region. Only valid together with both
 166 *                     BDRV_BLOCK_DATA and BDRV_BLOCK_OFFSET_VALID. Should not
 167 *                     appear with BDRV_BLOCK_ZERO.
 168 *
 169 * If BDRV_BLOCK_OFFSET_VALID is set, the map parameter represents the
 170 * host offset within the returned BDS that is allocated for the
 171 * corresponding raw guest data.  However, whether that offset
 172 * actually contains data also depends on BDRV_BLOCK_DATA, as follows:
 173 *
 174 * DATA ZERO OFFSET_VALID
 175 *  t    t        t       sectors read as zero, returned file is zero at offset
 176 *  t    f        t       sectors read as valid from file at offset
 177 *  f    t        t       sectors preallocated, read as zero, returned file not
 178 *                        necessarily zero at offset
 179 *  f    f        t       sectors preallocated but read from backing_hd,
 180 *                        returned file contains garbage at offset
 181 *  t    t        f       sectors preallocated, read as zero, unknown offset
 182 *  t    f        f       sectors read from unknown file or offset
 183 *  f    t        f       not allocated or unknown offset, read as zero
 184 *  f    f        f       not allocated or unknown offset, read from backing_hd
 185 */
 186#define BDRV_BLOCK_DATA         0x01
 187#define BDRV_BLOCK_ZERO         0x02
 188#define BDRV_BLOCK_OFFSET_VALID 0x04
 189#define BDRV_BLOCK_RAW          0x08
 190#define BDRV_BLOCK_ALLOCATED    0x10
 191#define BDRV_BLOCK_EOF          0x20
 192#define BDRV_BLOCK_RECURSE      0x40
 193#define BDRV_BLOCK_OFFSET_MASK  BDRV_SECTOR_MASK
 194
 195typedef QSIMPLEQ_HEAD(BlockReopenQueue, BlockReopenQueueEntry) BlockReopenQueue;
 196
 197typedef struct BDRVReopenState {
 198    BlockDriverState *bs;
 199    int flags;
 200    BlockdevDetectZeroesOptions detect_zeroes;
 201    bool backing_missing;
 202    bool replace_backing_bs;  /* new_backing_bs is ignored if this is false */
 203    BlockDriverState *new_backing_bs; /* If NULL then detach the current bs */
 204    uint64_t perm, shared_perm;
 205    QDict *options;
 206    QDict *explicit_options;
 207    void *opaque;
 208} BDRVReopenState;
 209
 210/*
 211 * Block operation types
 212 */
 213typedef enum BlockOpType {
 214    BLOCK_OP_TYPE_BACKUP_SOURCE,
 215    BLOCK_OP_TYPE_BACKUP_TARGET,
 216    BLOCK_OP_TYPE_CHANGE,
 217    BLOCK_OP_TYPE_COMMIT_SOURCE,
 218    BLOCK_OP_TYPE_COMMIT_TARGET,
 219    BLOCK_OP_TYPE_DATAPLANE,
 220    BLOCK_OP_TYPE_DRIVE_DEL,
 221    BLOCK_OP_TYPE_EJECT,
 222    BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
 223    BLOCK_OP_TYPE_INTERNAL_SNAPSHOT,
 224    BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
 225    BLOCK_OP_TYPE_MIRROR_SOURCE,
 226    BLOCK_OP_TYPE_MIRROR_TARGET,
 227    BLOCK_OP_TYPE_RESIZE,
 228    BLOCK_OP_TYPE_STREAM,
 229    BLOCK_OP_TYPE_REPLACE,
 230    BLOCK_OP_TYPE_MAX,
 231} BlockOpType;
 232
 233/* Block node permission constants */
 234enum {
 235    /**
 236     * A user that has the "permission" of consistent reads is guaranteed that
 237     * their view of the contents of the block device is complete and
 238     * self-consistent, representing the contents of a disk at a specific
 239     * point.
 240     *
 241     * For most block devices (including their backing files) this is true, but
 242     * the property cannot be maintained in a few situations like for
 243     * intermediate nodes of a commit block job.
 244     */
 245    BLK_PERM_CONSISTENT_READ    = 0x01,
 246
 247    /** This permission is required to change the visible disk contents. */
 248    BLK_PERM_WRITE              = 0x02,
 249
 250    /**
 251     * This permission (which is weaker than BLK_PERM_WRITE) is both enough and
 252     * required for writes to the block node when the caller promises that
 253     * the visible disk content doesn't change.
 254     *
 255     * As the BLK_PERM_WRITE permission is strictly stronger, either is
 256     * sufficient to perform an unchanging write.
 257     */
 258    BLK_PERM_WRITE_UNCHANGED    = 0x04,
 259
 260    /** This permission is required to change the size of a block node. */
 261    BLK_PERM_RESIZE             = 0x08,
 262
 263    /**
 264     * This permission is required to change the node that this BdrvChild
 265     * points to.
 266     */
 267    BLK_PERM_GRAPH_MOD          = 0x10,
 268
 269    BLK_PERM_ALL                = 0x1f,
 270
 271    DEFAULT_PERM_PASSTHROUGH    = BLK_PERM_CONSISTENT_READ
 272                                 | BLK_PERM_WRITE
 273                                 | BLK_PERM_WRITE_UNCHANGED
 274                                 | BLK_PERM_RESIZE,
 275
 276    DEFAULT_PERM_UNCHANGED      = BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH,
 277};
 278
 279char *bdrv_perm_names(uint64_t perm);
 280
 281/* disk I/O throttling */
 282void bdrv_init(void);
 283void bdrv_init_with_whitelist(void);
 284bool bdrv_uses_whitelist(void);
 285int bdrv_is_whitelisted(BlockDriver *drv, bool read_only);
 286BlockDriver *bdrv_find_protocol(const char *filename,
 287                                bool allow_protocol_prefix,
 288                                Error **errp);
 289BlockDriver *bdrv_find_format(const char *format_name);
 290int bdrv_create(BlockDriver *drv, const char* filename,
 291                QemuOpts *opts, Error **errp);
 292int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp);
 293BlockDriverState *bdrv_new(void);
 294void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
 295                 Error **errp);
 296void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
 297                       Error **errp);
 298
 299int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough);
 300int bdrv_parse_discard_flags(const char *mode, int *flags);
 301BdrvChild *bdrv_open_child(const char *filename,
 302                           QDict *options, const char *bdref_key,
 303                           BlockDriverState* parent,
 304                           const BdrvChildRole *child_role,
 305                           bool allow_none, Error **errp);
 306BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp);
 307void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
 308                         Error **errp);
 309int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
 310                           const char *bdref_key, Error **errp);
 311BlockDriverState *bdrv_open(const char *filename, const char *reference,
 312                            QDict *options, int flags, Error **errp);
 313BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
 314                                       int flags, Error **errp);
 315BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
 316                                    BlockDriverState *bs, QDict *options,
 317                                    bool keep_old_opts);
 318int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp);
 319int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
 320                              Error **errp);
 321int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
 322                        BlockReopenQueue *queue, Error **errp);
 323void bdrv_reopen_commit(BDRVReopenState *reopen_state);
 324void bdrv_reopen_abort(BDRVReopenState *reopen_state);
 325int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
 326                       int bytes, BdrvRequestFlags flags);
 327int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
 328int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes);
 329int bdrv_preadv(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
 330int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes);
 331int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov);
 332int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
 333                     const void *buf, int count);
 334/*
 335 * Efficiently zero a region of the disk image.  Note that this is a regular
 336 * I/O request like read or write and should have a reasonable size.  This
 337 * function is not suitable for zeroing the entire image in a single request
 338 * because it may allocate memory for the entire region.
 339 */
 340int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
 341                                       int bytes, BdrvRequestFlags flags);
 342BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
 343    const char *backing_file);
 344void bdrv_refresh_filename(BlockDriverState *bs);
 345
 346int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset,
 347                                  PreallocMode prealloc, Error **errp);
 348int bdrv_truncate(BdrvChild *child, int64_t offset, PreallocMode prealloc,
 349                  Error **errp);
 350
 351int64_t bdrv_nb_sectors(BlockDriverState *bs);
 352int64_t bdrv_getlength(BlockDriverState *bs);
 353int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
 354BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,
 355                               BlockDriverState *in_bs, Error **errp);
 356void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
 357void bdrv_refresh_limits(BlockDriverState *bs, Error **errp);
 358int bdrv_commit(BlockDriverState *bs);
 359int bdrv_change_backing_file(BlockDriverState *bs,
 360    const char *backing_file, const char *backing_fmt);
 361void bdrv_register(BlockDriver *bdrv);
 362int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
 363                           const char *backing_file_str);
 364BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
 365                                    BlockDriverState *bs);
 366BlockDriverState *bdrv_find_base(BlockDriverState *bs);
 367bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base,
 368                                  Error **errp);
 369int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base,
 370                              Error **errp);
 371void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base);
 372
 373
 374typedef struct BdrvCheckResult {
 375    int corruptions;
 376    int leaks;
 377    int check_errors;
 378    int corruptions_fixed;
 379    int leaks_fixed;
 380    int64_t image_end_offset;
 381    BlockFragInfo bfi;
 382} BdrvCheckResult;
 383
 384typedef enum {
 385    BDRV_FIX_LEAKS    = 1,
 386    BDRV_FIX_ERRORS   = 2,
 387} BdrvCheckMode;
 388
 389int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
 390
 391/* The units of offset and total_work_size may be chosen arbitrarily by the
 392 * block driver; total_work_size may change during the course of the amendment
 393 * operation */
 394typedef void BlockDriverAmendStatusCB(BlockDriverState *bs, int64_t offset,
 395                                      int64_t total_work_size, void *opaque);
 396int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
 397                       BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
 398                       Error **errp);
 399
 400/* external snapshots */
 401bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
 402                                      BlockDriverState *candidate);
 403bool bdrv_is_first_non_filter(BlockDriverState *candidate);
 404
 405/* check if a named node can be replaced when doing drive-mirror */
 406BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
 407                                        const char *node_name, Error **errp);
 408
 409/* async block I/O */
 410void bdrv_aio_cancel(BlockAIOCB *acb);
 411void bdrv_aio_cancel_async(BlockAIOCB *acb);
 412
 413/* sg packet commands */
 414int bdrv_co_ioctl(BlockDriverState *bs, int req, void *buf);
 415
 416/* Invalidate any cached metadata used by image formats */
 417void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp);
 418void bdrv_invalidate_cache_all(Error **errp);
 419int bdrv_inactivate_all(void);
 420
 421/* Ensure contents are flushed to disk.  */
 422int bdrv_flush(BlockDriverState *bs);
 423int coroutine_fn bdrv_co_flush(BlockDriverState *bs);
 424int bdrv_flush_all(void);
 425void bdrv_close_all(void);
 426void bdrv_drain(BlockDriverState *bs);
 427void coroutine_fn bdrv_co_drain(BlockDriverState *bs);
 428void bdrv_drain_all_begin(void);
 429void bdrv_drain_all_end(void);
 430void bdrv_drain_all(void);
 431
 432#define BDRV_POLL_WHILE(bs, cond) ({                       \
 433    BlockDriverState *bs_ = (bs);                          \
 434    AIO_WAIT_WHILE(bdrv_get_aio_context(bs_),              \
 435                   cond); })
 436
 437int bdrv_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
 438int bdrv_co_pdiscard(BdrvChild *child, int64_t offset, int64_t bytes);
 439int bdrv_has_zero_init_1(BlockDriverState *bs);
 440int bdrv_has_zero_init(BlockDriverState *bs);
 441bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs);
 442bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
 443int bdrv_block_status(BlockDriverState *bs, int64_t offset,
 444                      int64_t bytes, int64_t *pnum, int64_t *map,
 445                      BlockDriverState **file);
 446int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
 447                            int64_t offset, int64_t bytes, int64_t *pnum,
 448                            int64_t *map, BlockDriverState **file);
 449int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
 450                      int64_t *pnum);
 451int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
 452                            bool include_base, int64_t offset, int64_t bytes,
 453                            int64_t *pnum);
 454
 455bool bdrv_is_read_only(BlockDriverState *bs);
 456int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
 457                           bool ignore_allow_rdw, Error **errp);
 458int bdrv_apply_auto_read_only(BlockDriverState *bs, const char *errmsg,
 459                              Error **errp);
 460bool bdrv_is_writable(BlockDriverState *bs);
 461bool bdrv_is_sg(BlockDriverState *bs);
 462bool bdrv_is_inserted(BlockDriverState *bs);
 463void bdrv_lock_medium(BlockDriverState *bs, bool locked);
 464void bdrv_eject(BlockDriverState *bs, bool eject_flag);
 465const char *bdrv_get_format_name(BlockDriverState *bs);
 466BlockDriverState *bdrv_find_node(const char *node_name);
 467BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp);
 468XDbgBlockGraph *bdrv_get_xdbg_block_graph(Error **errp);
 469BlockDriverState *bdrv_lookup_bs(const char *device,
 470                                 const char *node_name,
 471                                 Error **errp);
 472bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
 473BlockDriverState *bdrv_next_node(BlockDriverState *bs);
 474BlockDriverState *bdrv_next_all_states(BlockDriverState *bs);
 475
 476typedef struct BdrvNextIterator {
 477    enum {
 478        BDRV_NEXT_BACKEND_ROOTS,
 479        BDRV_NEXT_MONITOR_OWNED,
 480    } phase;
 481    BlockBackend *blk;
 482    BlockDriverState *bs;
 483} BdrvNextIterator;
 484
 485BlockDriverState *bdrv_first(BdrvNextIterator *it);
 486BlockDriverState *bdrv_next(BdrvNextIterator *it);
 487void bdrv_next_cleanup(BdrvNextIterator *it);
 488
 489BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs);
 490bool bdrv_is_encrypted(BlockDriverState *bs);
 491void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
 492                         void *opaque, bool read_only);
 493const char *bdrv_get_node_name(const BlockDriverState *bs);
 494const char *bdrv_get_device_name(const BlockDriverState *bs);
 495const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
 496int bdrv_get_flags(BlockDriverState *bs);
 497int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
 498ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs,
 499                                          Error **errp);
 500void bdrv_round_to_clusters(BlockDriverState *bs,
 501                            int64_t offset, int64_t bytes,
 502                            int64_t *cluster_offset,
 503                            int64_t *cluster_bytes);
 504
 505void bdrv_get_backing_filename(BlockDriverState *bs,
 506                               char *filename, int filename_size);
 507char *bdrv_get_full_backing_filename(BlockDriverState *bs, Error **errp);
 508char *bdrv_get_full_backing_filename_from_filename(const char *backed,
 509                                                   const char *backing,
 510                                                   Error **errp);
 511char *bdrv_dirname(BlockDriverState *bs, Error **errp);
 512
 513int path_has_protocol(const char *path);
 514int path_is_absolute(const char *path);
 515char *path_combine(const char *base_path, const char *filename);
 516
 517int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 518int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 519int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
 520                      int64_t pos, int size);
 521
 522int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
 523                      int64_t pos, int size);
 524
 525void bdrv_img_create(const char *filename, const char *fmt,
 526                     const char *base_filename, const char *base_fmt,
 527                     char *options, uint64_t img_size, int flags,
 528                     bool quiet, Error **errp);
 529
 530/* Returns the alignment in bytes that is required so that no bounce buffer
 531 * is required throughout the stack */
 532size_t bdrv_min_mem_align(BlockDriverState *bs);
 533/* Returns optimal alignment in bytes for bounce buffer */
 534size_t bdrv_opt_mem_align(BlockDriverState *bs);
 535void *qemu_blockalign(BlockDriverState *bs, size_t size);
 536void *qemu_blockalign0(BlockDriverState *bs, size_t size);
 537void *qemu_try_blockalign(BlockDriverState *bs, size_t size);
 538void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
 539bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov);
 540
 541void bdrv_enable_copy_on_read(BlockDriverState *bs);
 542void bdrv_disable_copy_on_read(BlockDriverState *bs);
 543
 544void bdrv_ref(BlockDriverState *bs);
 545void bdrv_unref(BlockDriverState *bs);
 546void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child);
 547BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
 548                             BlockDriverState *child_bs,
 549                             const char *child_name,
 550                             const BdrvChildRole *child_role,
 551                             Error **errp);
 552
 553bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
 554void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);
 555void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason);
 556void bdrv_op_block_all(BlockDriverState *bs, Error *reason);
 557void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason);
 558bool bdrv_op_blocker_is_empty(BlockDriverState *bs);
 559
 560#define BLKDBG_EVENT(child, evt) \
 561    do { \
 562        if (child) { \
 563            bdrv_debug_event(child->bs, evt); \
 564        } \
 565    } while (0)
 566
 567void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
 568
 569int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
 570                           const char *tag);
 571int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag);
 572int bdrv_debug_resume(BlockDriverState *bs, const char *tag);
 573bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag);
 574
 575/**
 576 * bdrv_get_aio_context:
 577 *
 578 * Returns: the currently bound #AioContext
 579 */
 580AioContext *bdrv_get_aio_context(BlockDriverState *bs);
 581
 582/**
 583 * Transfer control to @co in the aio context of @bs
 584 */
 585void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co);
 586
 587void bdrv_set_aio_context_ignore(BlockDriverState *bs,
 588                                 AioContext *new_context, GSList **ignore);
 589int bdrv_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
 590                             Error **errp);
 591int bdrv_child_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,
 592                                   BdrvChild *ignore_child, Error **errp);
 593bool bdrv_child_can_set_aio_context(BdrvChild *c, AioContext *ctx,
 594                                    GSList **ignore, Error **errp);
 595bool bdrv_can_set_aio_context(BlockDriverState *bs, AioContext *ctx,
 596                              GSList **ignore, Error **errp);
 597int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz);
 598int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo);
 599
 600void bdrv_io_plug(BlockDriverState *bs);
 601void bdrv_io_unplug(BlockDriverState *bs);
 602
 603/**
 604 * bdrv_parent_drained_begin_single:
 605 *
 606 * Begin a quiesced section for the parent of @c. If @poll is true, wait for
 607 * any pending activity to cease.
 608 */
 609void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll);
 610
 611/**
 612 * bdrv_parent_drained_end_single:
 613 *
 614 * End a quiesced section for the parent of @c.
 615 *
 616 * This polls @bs's AioContext until all scheduled sub-drained_ends
 617 * have settled, which may result in graph changes.
 618 */
 619void bdrv_parent_drained_end_single(BdrvChild *c);
 620
 621/**
 622 * bdrv_drain_poll:
 623 *
 624 * Poll for pending requests in @bs, its parents (except for @ignore_parent),
 625 * and if @recursive is true its children as well (used for subtree drain).
 626 *
 627 * If @ignore_bds_parents is true, parents that are BlockDriverStates must
 628 * ignore the drain request because they will be drained separately (used for
 629 * drain_all).
 630 *
 631 * This is part of bdrv_drained_begin.
 632 */
 633bool bdrv_drain_poll(BlockDriverState *bs, bool recursive,
 634                     BdrvChild *ignore_parent, bool ignore_bds_parents);
 635
 636/**
 637 * bdrv_drained_begin:
 638 *
 639 * Begin a quiesced section for exclusive access to the BDS, by disabling
 640 * external request sources including NBD server and device model. Note that
 641 * this doesn't block timers or coroutines from submitting more requests, which
 642 * means block_job_pause is still necessary.
 643 *
 644 * This function can be recursive.
 645 */
 646void bdrv_drained_begin(BlockDriverState *bs);
 647
 648/**
 649 * bdrv_do_drained_begin_quiesce:
 650 *
 651 * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already
 652 * running requests to complete.
 653 */
 654void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,
 655                                   BdrvChild *parent, bool ignore_bds_parents);
 656
 657/**
 658 * Like bdrv_drained_begin, but recursively begins a quiesced section for
 659 * exclusive access to all child nodes as well.
 660 */
 661void bdrv_subtree_drained_begin(BlockDriverState *bs);
 662
 663/**
 664 * bdrv_drained_end:
 665 *
 666 * End a quiescent section started by bdrv_drained_begin().
 667 *
 668 * This polls @bs's AioContext until all scheduled sub-drained_ends
 669 * have settled.  On one hand, that may result in graph changes.  On
 670 * the other, this requires that the caller either runs in the main
 671 * loop; or that all involved nodes (@bs and all of its parents) are
 672 * in the caller's AioContext.
 673 */
 674void bdrv_drained_end(BlockDriverState *bs);
 675
 676/**
 677 * bdrv_drained_end_no_poll:
 678 *
 679 * Same as bdrv_drained_end(), but do not poll for the subgraph to
 680 * actually become unquiesced.  Therefore, no graph changes will occur
 681 * with this function.
 682 *
 683 * *drained_end_counter is incremented for every background operation
 684 * that is scheduled, and will be decremented for every operation once
 685 * it settles.  The caller must poll until it reaches 0.  The counter
 686 * should be accessed using atomic operations only.
 687 */
 688void bdrv_drained_end_no_poll(BlockDriverState *bs, int *drained_end_counter);
 689
 690/**
 691 * End a quiescent section started by bdrv_subtree_drained_begin().
 692 */
 693void bdrv_subtree_drained_end(BlockDriverState *bs);
 694
 695void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
 696                    Error **errp);
 697void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
 698
 699bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
 700                                     uint32_t granularity, Error **errp);
 701/**
 702 *
 703 * bdrv_register_buf/bdrv_unregister_buf:
 704 *
 705 * Register/unregister a buffer for I/O. For example, VFIO drivers are
 706 * interested to know the memory areas that would later be used for I/O, so
 707 * that they can prepare IOMMU mapping etc., to get better performance.
 708 */
 709void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size);
 710void bdrv_unregister_buf(BlockDriverState *bs, void *host);
 711
 712/**
 713 *
 714 * bdrv_co_copy_range:
 715 *
 716 * Do offloaded copy between two children. If the operation is not implemented
 717 * by the driver, or if the backend storage doesn't support it, a negative
 718 * error code will be returned.
 719 *
 720 * Note: block layer doesn't emulate or fallback to a bounce buffer approach
 721 * because usually the caller shouldn't attempt offloaded copy any more (e.g.
 722 * calling copy_file_range(2)) after the first error, thus it should fall back
 723 * to a read+write path in the caller level.
 724 *
 725 * @src: Source child to copy data from
 726 * @src_offset: offset in @src image to read data
 727 * @dst: Destination child to copy data to
 728 * @dst_offset: offset in @dst image to write data
 729 * @bytes: number of bytes to copy
 730 * @flags: request flags. Supported flags:
 731 *         BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero
 732 *                               write on @dst as if bdrv_co_pwrite_zeroes is
 733 *                               called. Used to simplify caller code, or
 734 *                               during BlockDriver.bdrv_co_copy_range_from()
 735 *                               recursion.
 736 *         BDRV_REQ_NO_SERIALISING - do not serialize with other overlapping
 737 *                                   requests currently in flight.
 738 *
 739 * Returns: 0 if succeeded; negative error code if failed.
 740 **/
 741int coroutine_fn bdrv_co_copy_range(BdrvChild *src, uint64_t src_offset,
 742                                    BdrvChild *dst, uint64_t dst_offset,
 743                                    uint64_t bytes, BdrvRequestFlags read_flags,
 744                                    BdrvRequestFlags write_flags);
 745#endif
 746