debian/patches/0002-add-basic-backup-support-to-block-driver.patch

   1 From 26891c19f68a14927e8c52417112d80668be1b3a Mon Sep 17 00:00:00 2001
   2 From: Dietmar Maurer <dietmar@proxmox.com>
   3 Date: Tue, 13 Nov 2012 10:03:52 +0100
   4 Subject: [PATCH v3 2/6] add basic backup support to block driver
   5
   6 Function backup_job_create() creates a block job to backup a block device.
   7 The coroutine is started with backup_job_start().
   8
   9 We call backup_do_cow() for each write during backup. That function
  10 reads the original data and pass it to backup_dump_cb().
  11
  12 The tracked_request infrastructure is used to serialize access.
  13
  14 Currently backup cluster size is hardcoded to 65536 bytes.
  15
  16 Signed-off-by: Dietmar Maurer <dietmar@proxmox.com>
  17 ---
  18  Makefile.objs |    1 +
  19  backup.c      |  335 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  20  backup.h      |   32 ++++++
  21  block.c       |   71 +++++++++++-
  22  block.h       |    2 +
  23  blockjob.h    |   10 ++
  24  6 files changed, 445 insertions(+), 6 deletions(-)
  25  create mode 100644 backup.c
  26  create mode 100644 backup.h
  27
  28 diff --git a/Makefile.objs b/Makefile.objs
  29 index 3c7abca..cb46be5 100644
  30 --- a/Makefile.objs
  31 +++ b/Makefile.objs
  32 @@ -48,6 +48,7 @@ coroutine-obj-$(CONFIG_WIN32) += coroutine-win32.o
  33  block-obj-y = iov.o cache-utils.o qemu-option.o module.o async.o
  34  block-obj-y += nbd.o block.o blockjob.o aes.o qemu-config.o
  35  block-obj-y += thread-pool.o qemu-progress.o qemu-sockets.o uri.o notify.o
  36 +block-obj-y += backup.o
  37  block-obj-y += $(coroutine-obj-y) $(qobject-obj-y) $(version-obj-y)
  38  block-obj-$(CONFIG_POSIX) += event_notifier-posix.o aio-posix.o
  39  block-obj-$(CONFIG_WIN32) += event_notifier-win32.o aio-win32.o
  40 diff --git a/backup.c b/backup.c
  41 new file mode 100644
  42 index 0000000..3ccb74c
  43 --- /dev/null
  44 +++ b/backup.c
  45 @@ -0,0 +1,335 @@
  46 +/*
  47 + * QEMU backup
  48 + *
  49 + * Copyright (C) 2012 Proxmox Server Solutions
  50 + *
  51 + * Authors:
  52 + *  Dietmar Maurer (dietmar@proxmox.com)
  53 + *
  54 + * This work is licensed under the terms of the GNU GPL, version 2 or later.
  55 + * See the COPYING file in the top-level directory.
  56 + *
  57 + */
  58 +
  59 +#include <stdio.h>
  60 +#include <errno.h>
  61 +#include <unistd.h>
  62 +
  63 +#include "block.h"
  64 +#include "block_int.h"
  65 +#include "blockjob.h"
  66 +#include "qemu/ratelimit.h"
  67 +#include "backup.h"
  68 +
  69 +#define DEBUG_BACKUP 0
  70 +
  71 +#define DPRINTF(fmt, ...) \
  72 +    do { if (DEBUG_BACKUP) { printf("backup: " fmt, ## __VA_ARGS__); } } \
  73 +    while (0)
  74 +
  75 +
  76 +#define BITS_PER_LONG  (sizeof(unsigned long) * 8)
  77 +#define SLICE_TIME 100000000ULL /* ns */
  78 +
  79 +typedef struct BackupBlockJob {
  80 +    BlockJob common;
  81 +    RateLimit limit;
  82 +    uint64_t sectors_read;
  83 +    unsigned long *bitmap;
  84 +    int bitmap_size;
  85 +    BackupDumpFunc *backup_dump_cb;
  86 +    BlockDriverCompletionFunc *backup_complete_cb;
  87 +    void *opaque;
  88 +} BackupBlockJob;
  89 +
  90 +static int backup_get_bitmap(BackupBlockJob *job, int64_t cluster_num)
  91 +{
  92 +    assert(job);
  93 +    assert(job->bitmap);
  94 +
  95 +    unsigned long val, idx, bit;
  96 +
  97 +    idx = cluster_num / BITS_PER_LONG;
  98 +
  99 +    assert(job->bitmap_size > idx);
 100 +
 101 +    bit = cluster_num % BITS_PER_LONG;
 102 +    val = job->bitmap[idx];
 103 +
 104 +    return !!(val & (1UL << bit));
 105 +}
 106 +
 107 +static void backup_set_bitmap(BackupBlockJob *job, int64_t cluster_num,
 108 +                              int dirty)
 109 +{
 110 +    assert(job);
 111 +    assert(job->bitmap);
 112 +
 113 +    unsigned long val, idx, bit;
 114 +
 115 +    idx = cluster_num / BITS_PER_LONG;
 116 +
 117 +    assert(job->bitmap_size > idx);
 118 +
 119 +    bit = cluster_num % BITS_PER_LONG;
 120 +    val = job->bitmap[idx];
 121 +    if (dirty) {
 122 +        if (!(val & (1UL << bit))) {
 123 +            val |= 1UL << bit;
 124 +        }
 125 +    } else {
 126 +        if (val & (1UL << bit)) {
 127 +            val &= ~(1UL << bit);
 128 +        }
 129 +    }
 130 +    job->bitmap[idx] = val;
 131 +}
 132 +
 133 +static int backup_in_progress_count;
 134 +
 135 +static int coroutine_fn backup_do_cow(BlockDriverState *bs,
 136 +                                      int64_t sector_num, int nb_sectors)
 137 +{
 138 +    assert(bs);
 139 +    BackupBlockJob *job = (BackupBlockJob *)bs->job;
 140 +    assert(job);
 141 +
 142 +    BlockDriver *drv = bs->drv;
 143 +    struct iovec iov;
 144 +    QEMUIOVector bounce_qiov;
 145 +    void *bounce_buffer = NULL;
 146 +    int ret = 0;
 147 +
 148 +    backup_in_progress_count++;
 149 +
 150 +    int64_t start, end;
 151 +
 152 +    start = sector_num / BACKUP_BLOCKS_PER_CLUSTER;
 153 +    end = (sector_num + nb_sectors + BACKUP_BLOCKS_PER_CLUSTER - 1) /
 154 +        BACKUP_BLOCKS_PER_CLUSTER;
 155 +
 156 +    DPRINTF("brdv_co_backup_cow enter %s C%zd %zd %d\n",
 157 +            bdrv_get_device_name(bs), start, sector_num, nb_sectors);
 158 +
 159 +    for (; start < end; start++) {
 160 +        if (backup_get_bitmap(job, start)) {
 161 +            DPRINTF("brdv_co_backup_cow skip C%zd\n", start);
 162 +            continue; /* already copied */
 163 +        }
 164 +
 165 +        /* immediately set bitmap (avoid coroutine race) */
 166 +        backup_set_bitmap(job, start, 1);
 167 +
 168 +        DPRINTF("brdv_co_backup_cow C%zd\n", start);
 169 +
 170 +        if (!bounce_buffer) {
 171 +            iov.iov_len = BACKUP_CLUSTER_SIZE;
 172 +            iov.iov_base = bounce_buffer = qemu_blockalign(bs, iov.iov_len);
 173 +            qemu_iovec_init_external(&bounce_qiov, &iov, 1);
 174 +        }
 175 +
 176 +        ret = drv->bdrv_co_readv(bs, start * BACKUP_BLOCKS_PER_CLUSTER,
 177 +                                 BACKUP_BLOCKS_PER_CLUSTER,
 178 +                                 &bounce_qiov);
 179 +
 180 +        job->sectors_read += BACKUP_BLOCKS_PER_CLUSTER;
 181 +
 182 +        if (ret < 0) {
 183 +            DPRINTF("brdv_co_backup_cow bdrv_read C%zd failed\n", start);
 184 +            goto out;
 185 +        }
 186 +
 187 +        ret = job->backup_dump_cb(job->opaque, bs, start, bounce_buffer);
 188 +        if (ret < 0) {
 189 +            DPRINTF("brdv_co_backup_cow dump_cluster_cb C%zd failed\n", start);
 190 +            goto out;
 191 +        }
 192 +
 193 +        DPRINTF("brdv_co_backup_cow done C%zd\n", start);
 194 +    }
 195 +
 196 +out:
 197 +    if (bounce_buffer) {
 198 +        qemu_vfree(bounce_buffer);
 199 +    }
 200 +
 201 +    backup_in_progress_count--;
 202 +
 203 +    return ret;
 204 +}
 205 +
 206 +static int coroutine_fn backup_before_read(BlockDriverState *bs,
 207 +                                           int64_t sector_num,
 208 +                                           int nb_sectors, QEMUIOVector *qiov)
 209 +{
 210 +    return backup_do_cow(bs, sector_num, nb_sectors);
 211 +}
 212 +
 213 +static int coroutine_fn backup_before_write(BlockDriverState *bs,
 214 +                                            int64_t sector_num,
 215 +                                            int nb_sectors, QEMUIOVector *qiov)
 216 +{
 217 +    return backup_do_cow(bs, sector_num, nb_sectors);
 218 +}
 219 +
 220 +static void backup_set_speed(BlockJob *job, int64_t speed, Error **errp)
 221 +{
 222 +    BackupBlockJob *s = container_of(job, BackupBlockJob, common);
 223 +
 224 +    if (speed < 0) {
 225 +        error_set(errp, QERR_INVALID_PARAMETER, "speed");
 226 +        return;
 227 +    }
 228 +    ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME);
 229 +}
 230 +
 231 +static BlockJobType backup_job_type = {
 232 +    .instance_size = sizeof(BackupBlockJob),
 233 +    .before_read = backup_before_read,
 234 +    .before_write = backup_before_write,
 235 +    .job_type = "backup",
 236 +    .set_speed = backup_set_speed,
 237 +};
 238 +
 239 +static void coroutine_fn backup_run(void *opaque)
 240 +{
 241 +    BackupBlockJob *job = opaque;
 242 +    BlockDriverState *bs = job->common.bs;
 243 +    assert(bs);
 244 +
 245 +    int64_t start, end;
 246 +
 247 +    start = 0;
 248 +    end = (bs->total_sectors + BACKUP_BLOCKS_PER_CLUSTER - 1) /
 249 +        BACKUP_BLOCKS_PER_CLUSTER;
 250 +
 251 +    DPRINTF("backup_run start %s %zd %zd\n", bdrv_get_device_name(bs),
 252 +            start, end);
 253 +
 254 +    int ret = 0;
 255 +
 256 +    for (; start < end; start++) {
 257 +        if (block_job_is_cancelled(&job->common)) {
 258 +            ret = -1;
 259 +            break;
 260 +        }
 261 +
 262 +        /* we need to yield so that qemu_aio_flush() returns.
 263 +         * (without, VM does not reboot)
 264 +        * Note: use 1000 instead of 0 (0 priorize this task too much)
 265 +         */
 266 +       if (job->common.speed) {
 267 +            uint64_t delay_ns = ratelimit_calculate_delay(
 268 +                &job->limit, job->sectors_read);
 269 +            job->sectors_read = 0;
 270 +            block_job_sleep_ns(&job->common, rt_clock, delay_ns);
 271 +       } else {
 272 +            block_job_sleep_ns(&job->common, rt_clock, 1000);
 273 +       }
 274 +
 275 +        if (block_job_is_cancelled(&job->common)) {
 276 +            ret = -1;
 277 +            break;
 278 +        }
 279 +
 280 +        if (backup_get_bitmap(job, start)) {
 281 +            continue; /* already copied */
 282 +        }
 283 +
 284 +        DPRINTF("backup_run loop C%zd\n", start);
 285 +
 286 +        /**
 287 +         * This triggers a cluster copy
 288 +         * Note: avoid direct call to brdv_co_backup_cow, because
 289 +         * this does not call tracked_request_begin()
 290 +         */
 291 +        ret = bdrv_co_backup(bs, start*BACKUP_BLOCKS_PER_CLUSTER, 1);
 292 +        if (ret < 0) {
 293 +            break;
 294 +        }
 295 +        /* Publish progress */
 296 +        job->common.offset += BACKUP_CLUSTER_SIZE;
 297 +    }
 298 +
 299 +    while (backup_in_progress_count > 0) {
 300 +        DPRINTF("backup_run backup_in_progress_count != 0 (%d)",
 301 +                backup_in_progress_count);
 302 +        block_job_sleep_ns(&job->common, rt_clock, 10000);
 303 +
 304 +    }
 305 +
 306 +    DPRINTF("backup_run complete %d\n", ret);
 307 +    block_job_completed(&job->common, ret);
 308 +}
 309 +
 310 +static void backup_job_cleanup_cb(void *opaque, int ret)
 311 +{
 312 +    BlockDriverState *bs = opaque;
 313 +    assert(bs);
 314 +    BackupBlockJob *job = (BackupBlockJob *)bs->job;
 315 +    assert(job);
 316 +
 317 +    DPRINTF("backup_job_cleanup_cb start %d\n", ret);
 318 +
 319 +    job->backup_complete_cb(job->opaque, ret);
 320 +
 321 +    DPRINTF("backup_job_cleanup_cb end\n");
 322 +
 323 +    g_free(job->bitmap);
 324 +}
 325 +
 326 +void
 327 +backup_job_start(BlockDriverState *bs)
 328 +{
 329 +    assert(bs);
 330 +    assert(bs->job);
 331 +    assert(bs->job->co == NULL);
 332 +
 333 +    bs->job->co = qemu_coroutine_create(backup_run);
 334 +    qemu_coroutine_enter(bs->job->co, bs->job);
 335 +}
 336 +
 337 +int
 338 +backup_job_create(BlockDriverState *bs, BackupDumpFunc *backup_dump_cb,
 339 +                  BlockDriverCompletionFunc *backup_complete_cb,
 340 +                  void *opaque, int64_t speed)
 341 +{
 342 +    assert(bs);
 343 +    assert(backup_dump_cb);
 344 +    assert(backup_complete_cb);
 345 +
 346 +    if (bs->job) {
 347 +        DPRINTF("bdrv_backup_init failed - running job on %s\n",
 348 +                bdrv_get_device_name(bs));
 349 +        return -1;
 350 +    }
 351 +
 352 +    int64_t bitmap_size;
 353 +    const char *devname = bdrv_get_device_name(bs);
 354 +
 355 +    if (!devname || !devname[0]) {
 356 +        return -1;
 357 +    }
 358 +
 359 +    DPRINTF("bdrv_backup_init %s\n", bdrv_get_device_name(bs));
 360 +
 361 +    Error *errp;
 362 +    BackupBlockJob *job = block_job_create(&backup_job_type, bs, speed,
 363 +                                           backup_job_cleanup_cb, bs, &errp);
 364 +
 365 +    job->common.cluster_size = BACKUP_CLUSTER_SIZE;
 366 +
 367 +    bitmap_size = bs->total_sectors +
 368 +        BACKUP_BLOCKS_PER_CLUSTER * BITS_PER_LONG - 1;
 369 +    bitmap_size /= BACKUP_BLOCKS_PER_CLUSTER * BITS_PER_LONG;
 370 +
 371 +    job->backup_dump_cb = backup_dump_cb;
 372 +    job->backup_complete_cb = backup_complete_cb;
 373 +    job->opaque = opaque;
 374 +    job->bitmap_size = bitmap_size;
 375 +    job->bitmap = g_new0(unsigned long, bitmap_size);
 376 +
 377 +    job->common.len = bs->total_sectors*BDRV_SECTOR_SIZE;
 378 +
 379 +    return 0;
 380 +}
 381 diff --git a/backup.h b/backup.h
 382 new file mode 100644
 383 index 0000000..a5f85e6
 384 --- /dev/null
 385 +++ b/backup.h
 386 @@ -0,0 +1,32 @@
 387 +/*
 388 + * QEMU backup related definitions
 389 + *
 390 + * Copyright (C) Proxmox Server Solutions
 391 + *
 392 + * Authors:
 393 + *  Dietmar Maurer (dietmar@proxmox.com)
 394 + *
 395 + * This work is licensed under the terms of the GNU GPL, version 2 or later.
 396 + * See the COPYING file in the top-level directory.
 397 + *
 398 + */
 399 +
 400 +#ifndef QEMU_BACKUP_H
 401 +#define QEMU_BACKUP_H
 402 +
 403 +#include <uuid/uuid.h>
 404 +
 405 +#define BACKUP_CLUSTER_BITS 16
 406 +#define BACKUP_CLUSTER_SIZE (1<<BACKUP_CLUSTER_BITS)
 407 +#define BACKUP_BLOCKS_PER_CLUSTER (BACKUP_CLUSTER_SIZE/BDRV_SECTOR_SIZE)
 408 +
 409 +typedef int BackupDumpFunc(void *opaque, BlockDriverState *bs,
 410 +                           int64_t cluster_num, unsigned char *buf);
 411 +
 412 +void backup_job_start(BlockDriverState *bs);
 413 +
 414 +int backup_job_create(BlockDriverState *bs, BackupDumpFunc *backup_dump_cb,
 415 +                     BlockDriverCompletionFunc *backup_complete_cb,
 416 +                     void *opaque, int64_t speed);
 417 +
 418 +#endif /* QEMU_BACKUP_H */
 419 diff --git a/block.c b/block.c
 420 index c05875f..4de7fbd 100644
 421 --- a/block.c
 422 +++ b/block.c
 423 @@ -54,6 +54,7 @@
 424  typedef enum {
 425      BDRV_REQ_COPY_ON_READ = 0x1,
 426      BDRV_REQ_ZERO_WRITE   = 0x2,
 427 +    BDRV_REQ_BACKUP_ONLY  = 0x4,
 428  } BdrvRequestFlags;
 429
 430  static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load);
 431 @@ -1542,7 +1543,7 @@ int bdrv_commit(BlockDriverState *bs)
 432
 433      if (!drv)
 434          return -ENOMEDIUM;
 435 -
 436 +
 437      if (!bs->backing_hd) {
 438          return -ENOTSUP;
 439      }
 440 @@ -1679,6 +1680,22 @@ static void round_to_clusters(BlockDriverState *bs,
 441      }
 442  }
 443
 444 +/**
 445 + * Round a region to job cluster boundaries
 446 + */
 447 +static void round_to_job_clusters(BlockDriverState *bs,
 448 +                                  int64_t sector_num, int nb_sectors,
 449 +                                  int job_cluster_size,
 450 +                                  int64_t *cluster_sector_num,
 451 +                                  int *cluster_nb_sectors)
 452 +{
 453 +    int64_t c = job_cluster_size/BDRV_SECTOR_SIZE;
 454 +
 455 +    *cluster_sector_num = QEMU_ALIGN_DOWN(sector_num, c);
 456 +    *cluster_nb_sectors = QEMU_ALIGN_UP(sector_num - *cluster_sector_num +
 457 +                                        nb_sectors, c);
 458 +}
 459 +
 460  static bool tracked_request_overlaps(BdrvTrackedRequest *req,
 461                                       int64_t sector_num, int nb_sectors) {
 462      /*        aaaa   bbbb */
 463 @@ -1693,7 +1710,9 @@ static bool tracked_request_overlaps(BdrvTrackedRequest *req,
 464  }
 465
 466  static void coroutine_fn wait_for_overlapping_requests(BlockDriverState *bs,
 467 -        int64_t sector_num, int nb_sectors)
 468 +                                                       int64_t sector_num,
 469 +                                                       int nb_sectors,
 470 +                                                       int job_cluster_size)
 471  {
 472      BdrvTrackedRequest *req;
 473      int64_t cluster_sector_num;
 474 @@ -1709,6 +1728,11 @@ static void coroutine_fn wait_for_overlapping_requests(BlockDriverState *bs,
 475      round_to_clusters(bs, sector_num, nb_sectors,
 476                        &cluster_sector_num, &cluster_nb_sectors);
 477
 478 +    if (job_cluster_size) {
 479 +        round_to_job_clusters(bs, sector_num, nb_sectors, job_cluster_size,
 480 +                              &cluster_sector_num, &cluster_nb_sectors);
 481 +    }
 482 +
 483      do {
 484          retry = false;
 485          QLIST_FOREACH(req, &bs->tracked_requests, list) {
 486 @@ -2278,12 +2302,24 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
 487          bs->copy_on_read_in_flight++;
 488      }
 489
 490 -    if (bs->copy_on_read_in_flight) {
 491 -        wait_for_overlapping_requests(bs, sector_num, nb_sectors);
 492 +    int job_cluster_size = bs->job && bs->job->cluster_size ?
 493 +        bs->job->cluster_size : 0;
 494 +
 495 +    if (bs->copy_on_read_in_flight || job_cluster_size) {
 496 +        wait_for_overlapping_requests(bs, sector_num, nb_sectors,
 497 +                                      job_cluster_size);
 498      }
 499
 500      tracked_request_begin(&req, bs, sector_num, nb_sectors, false);
 501
 502 +    if (bs->job && bs->job->job_type->before_read) {
 503 +        ret = bs->job->job_type->before_read(bs, sector_num, nb_sectors, qiov);
 504 +        if ((ret < 0) || (flags & BDRV_REQ_BACKUP_ONLY)) {
 505 +            /* Note: We do not return any data to the caller */
 506 +            goto out;
 507 +        }
 508 +    }
 509 +
 510      if (flags & BDRV_REQ_COPY_ON_READ) {
 511          int pnum;
 512
 513 @@ -2327,6 +2363,17 @@ int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState *bs,
 514                              BDRV_REQ_COPY_ON_READ);
 515  }
 516
 517 +int coroutine_fn bdrv_co_backup(BlockDriverState *bs,
 518 +    int64_t sector_num, int nb_sectors)
 519 +{
 520 +    if (!bs->job) {
 521 +        return -ENOTSUP;
 522 +    }
 523 +
 524 +    return bdrv_co_do_readv(bs, sector_num, nb_sectors, NULL,
 525 +                            BDRV_REQ_BACKUP_ONLY);
 526 +}
 527 +
 528  static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
 529      int64_t sector_num, int nb_sectors)
 530  {
 531 @@ -2384,12 +2431,23 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
 532          bdrv_io_limits_intercept(bs, true, nb_sectors);
 533      }
 534
 535 -    if (bs->copy_on_read_in_flight) {
 536 -        wait_for_overlapping_requests(bs, sector_num, nb_sectors);
 537 +    int job_cluster_size = bs->job && bs->job->cluster_size ?
 538 +        bs->job->cluster_size : 0;
 539 +
 540 +    if (bs->copy_on_read_in_flight || job_cluster_size) {
 541 +        wait_for_overlapping_requests(bs, sector_num, nb_sectors,
 542 +                                      job_cluster_size);
 543      }
 544
 545      tracked_request_begin(&req, bs, sector_num, nb_sectors, true);
 546
 547 +    if (bs->job && bs->job->job_type->before_write) {
 548 +        ret = bs->job->job_type->before_write(bs, sector_num, nb_sectors, qiov);
 549 +        if (ret < 0) {
 550 +            goto out;
 551 +        }
 552 +    }
 553 +
 554      if (flags & BDRV_REQ_ZERO_WRITE) {
 555          ret = bdrv_co_do_write_zeroes(bs, sector_num, nb_sectors);
 556      } else {
 557 @@ -2408,6 +2466,7 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
 558          bs->wr_highest_sector = sector_num + nb_sectors - 1;
 559      }
 560
 561 +out:
 562      tracked_request_end(&req);
 563
 564      return ret;
 565 diff --git a/block.h b/block.h
 566 index 722c620..94e5903 100644
 567 --- a/block.h
 568 +++ b/block.h
 569 @@ -172,6 +172,8 @@ int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num,
 570      int nb_sectors, QEMUIOVector *qiov);
 571  int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState *bs,
 572      int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
 573 +int coroutine_fn bdrv_co_backup(BlockDriverState *bs,
 574 +    int64_t sector_num, int nb_sectors);
 575  int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num,
 576      int nb_sectors, QEMUIOVector *qiov);
 577  /*
 578 diff --git a/blockjob.h b/blockjob.h
 579 index 3792b73..6621173 100644
 580 --- a/blockjob.h
 581 +++ b/blockjob.h
 582 @@ -50,6 +50,13 @@ typedef struct BlockJobType {
 583       * manually.
 584       */
 585      void (*complete)(BlockJob *job, Error **errp);
 586 +
 587 +    /** tracked requests */
 588 +    int coroutine_fn (*before_read)(BlockDriverState *bs, int64_t sector_num,
 589 +                                    int nb_sectors, QEMUIOVector *qiov);
 590 +    int coroutine_fn (*before_write)(BlockDriverState *bs, int64_t sector_num,
 591 +                                     int nb_sectors, QEMUIOVector *qiov);
 592 +
 593  } BlockJobType;
 594
 595  /**
 596 @@ -103,6 +110,9 @@ struct BlockJob {
 597      /** Speed that was set with @block_job_set_speed.  */
 598      int64_t speed;
 599
 600 +    /** tracked requests */
 601 +    int cluster_size;
 602 +
 603      /** The completion function that will be called when the job completes.  */
 604      BlockDriverCompletionFunc *cb;
 605
 606 --
 607 1.7.2.5
 608