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1
/*
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 * Block protocol for block driver correctness testing
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 *
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 * Copyright (C) 2010 IBM, Corp.
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 *
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 * This work is licensed under the terms of the GNU GPL, version 2 or later.
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 * See the COPYING file in the top-level directory.
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 */
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#include <stdarg.h>
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#include "qemu/sockets.h" /* for EINPROGRESS on Windows */
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#include "block/block_int.h"
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typedef struct {
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    BlockDriverState *test_file;
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} BDRVBlkverifyState;
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typedef struct BlkverifyAIOCB BlkverifyAIOCB;
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struct BlkverifyAIOCB {
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    BlockDriverAIOCB common;
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    QEMUBH *bh;
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    /* Request metadata */
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    bool is_write;
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    int64_t sector_num;
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    int nb_sectors;
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    int ret;                    /* first completed request's result */
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    unsigned int done;          /* completion counter */
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    bool *finished;             /* completion signal for cancel */
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    QEMUIOVector *qiov;         /* user I/O vector */
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    QEMUIOVector raw_qiov;      /* cloned I/O vector for raw file */
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    void *buf;                  /* buffer for raw file I/O */
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    void (*verify)(BlkverifyAIOCB *acb);
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};
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static void blkverify_aio_cancel(BlockDriverAIOCB *blockacb)
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{
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    BlkverifyAIOCB *acb = (BlkverifyAIOCB *)blockacb;
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    bool finished = false;
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    /* Wait until request completes, invokes its callback, and frees itself */
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    acb->finished = &finished;
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    while (!finished) {
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        qemu_aio_wait();
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    }
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}
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static const AIOCBInfo blkverify_aiocb_info = {
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    .aiocb_size         = sizeof(BlkverifyAIOCB),
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    .cancel             = blkverify_aio_cancel,
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};
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static void GCC_FMT_ATTR(2, 3) blkverify_err(BlkverifyAIOCB *acb,
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                                             const char *fmt, ...)
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{
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    va_list ap;
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    va_start(ap, fmt);
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    fprintf(stderr, "blkverify: %s sector_num=%" PRId64 " nb_sectors=%d ",
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            acb->is_write ? "write" : "read", acb->sector_num,
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            acb->nb_sectors);
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    vfprintf(stderr, fmt, ap);
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    fprintf(stderr, "\n");
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    va_end(ap);
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    exit(1);
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}
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/* Valid blkverify filenames look like blkverify:path/to/raw_image:path/to/image */
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static void blkverify_parse_filename(const char *filename, QDict *options,
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                                     Error **errp)
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{
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    const char *c;
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    QString *raw_path;
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    /* Parse the blkverify: prefix */
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    if (!strstart(filename, "blkverify:", &filename)) {
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        error_setg(errp, "File name string must start with 'blkverify:'");
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        return;
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    }
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    /* Parse the raw image filename */
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    c = strchr(filename, ':');
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    if (c == NULL) {
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        error_setg(errp, "blkverify requires raw copy and original image path");
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        return;
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    }
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    /* TODO Implement option pass-through and set raw.filename here */
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    raw_path = qstring_from_substr(filename, 0, c - filename - 1);
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    qdict_put(options, "x-raw", raw_path);
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    /* TODO Allow multi-level nesting and set file.filename here */
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    filename = c + 1;
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    qdict_put(options, "x-image", qstring_from_str(filename));
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}
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static QemuOptsList runtime_opts = {
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    .name = "blkverify",
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    .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
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    .desc = {
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        {
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            .name = "x-raw",
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            .type = QEMU_OPT_STRING,
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            .help = "[internal use only, will be removed]",
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        },
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        {
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            .name = "x-image",
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            .type = QEMU_OPT_STRING,
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            .help = "[internal use only, will be removed]",
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        },
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        { /* end of list */ }
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    },
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};
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static int blkverify_open(BlockDriverState *bs, QDict *options, int flags,
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                          Error **errp)
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{
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    BDRVBlkverifyState *s = bs->opaque;
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    QemuOpts *opts;
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    Error *local_err = NULL;
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    const char *filename, *raw;
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    int ret;
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    opts = qemu_opts_create_nofail(&runtime_opts);
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    qemu_opts_absorb_qdict(opts, options, &local_err);
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    if (error_is_set(&local_err)) {
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        qerror_report_err(local_err);
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        error_free(local_err);
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        ret = -EINVAL;
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        goto fail;
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    }
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    /* Parse the raw image filename */
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    raw = qemu_opt_get(opts, "x-raw");
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    if (raw == NULL) {
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        ret = -EINVAL;
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        goto fail;
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    }
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    ret = bdrv_file_open(&bs->file, raw, NULL, flags, &local_err);
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    if (ret < 0) {
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        qerror_report_err(local_err);
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        error_free(local_err);
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        goto fail;
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    }
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    /* Open the test file */
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    filename = qemu_opt_get(opts, "x-image");
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    if (filename == NULL) {
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        ret = -EINVAL;
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        goto fail;
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    }
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    s->test_file = bdrv_new("");
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    ret = bdrv_open(s->test_file, filename, NULL, flags, NULL, &local_err);
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    if (ret < 0) {
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        qerror_report_err(local_err);
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        error_free(local_err);
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        bdrv_unref(s->test_file);
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        s->test_file = NULL;
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        goto fail;
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    }
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    ret = 0;
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fail:
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    return ret;
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}
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static void blkverify_close(BlockDriverState *bs)
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{
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    BDRVBlkverifyState *s = bs->opaque;
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    bdrv_unref(s->test_file);
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    s->test_file = NULL;
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}
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static int64_t blkverify_getlength(BlockDriverState *bs)
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{
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    BDRVBlkverifyState *s = bs->opaque;
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    return bdrv_getlength(s->test_file);
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}
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/**
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 * Check that I/O vector contents are identical
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 *
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 * @a:          I/O vector
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 * @b:          I/O vector
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 * @ret:        Offset to first mismatching byte or -1 if match
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 */
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static ssize_t blkverify_iovec_compare(QEMUIOVector *a, QEMUIOVector *b)
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{
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    int i;
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    ssize_t offset = 0;
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    assert(a->niov == b->niov);
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    for (i = 0; i < a->niov; i++) {
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        size_t len = 0;
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        uint8_t *p = (uint8_t *)a->iov[i].iov_base;
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        uint8_t *q = (uint8_t *)b->iov[i].iov_base;
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        assert(a->iov[i].iov_len == b->iov[i].iov_len);
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        while (len < a->iov[i].iov_len && *p++ == *q++) {
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            len++;
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        }
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        offset += len;
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        if (len != a->iov[i].iov_len) {
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            return offset;
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        }
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    }
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    return -1;
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}
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typedef struct {
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    int src_index;
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    struct iovec *src_iov;
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    void *dest_base;
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} IOVectorSortElem;
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static int sortelem_cmp_src_base(const void *a, const void *b)
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{
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    const IOVectorSortElem *elem_a = a;
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    const IOVectorSortElem *elem_b = b;
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    /* Don't overflow */
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    if (elem_a->src_iov->iov_base < elem_b->src_iov->iov_base) {
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        return -1;
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    } else if (elem_a->src_iov->iov_base > elem_b->src_iov->iov_base) {
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        return 1;
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    } else {
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        return 0;
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    }
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}
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static int sortelem_cmp_src_index(const void *a, const void *b)
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{
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    const IOVectorSortElem *elem_a = a;
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    const IOVectorSortElem *elem_b = b;
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    return elem_a->src_index - elem_b->src_index;
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}
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/**
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 * Copy contents of I/O vector
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 *
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 * The relative relationships of overlapping iovecs are preserved.  This is
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 * necessary to ensure identical semantics in the cloned I/O vector.
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 */
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static void blkverify_iovec_clone(QEMUIOVector *dest, const QEMUIOVector *src,
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                                  void *buf)
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{
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    IOVectorSortElem sortelems[src->niov];
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    void *last_end;
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    int i;
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    /* Sort by source iovecs by base address */
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    for (i = 0; i < src->niov; i++) {
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        sortelems[i].src_index = i;
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        sortelems[i].src_iov = &src->iov[i];
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    }
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    qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_base);
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    /* Allocate buffer space taking into account overlapping iovecs */
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    last_end = NULL;
271
    for (i = 0; i < src->niov; i++) {
272
        struct iovec *cur = sortelems[i].src_iov;
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        ptrdiff_t rewind = 0;
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275
        /* Detect overlap */
276
        if (last_end && last_end > cur->iov_base) {
277
            rewind = last_end - cur->iov_base;
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        }
279

    
280
        sortelems[i].dest_base = buf - rewind;
281
        buf += cur->iov_len - MIN(rewind, cur->iov_len);
282
        last_end = MAX(cur->iov_base + cur->iov_len, last_end);
283
    }
284

    
285
    /* Sort by source iovec index and build destination iovec */
286
    qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_index);
287
    for (i = 0; i < src->niov; i++) {
288
        qemu_iovec_add(dest, sortelems[i].dest_base, src->iov[i].iov_len);
289
    }
290
}
291

    
292
static BlkverifyAIOCB *blkverify_aio_get(BlockDriverState *bs, bool is_write,
293
                                         int64_t sector_num, QEMUIOVector *qiov,
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                                         int nb_sectors,
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                                         BlockDriverCompletionFunc *cb,
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                                         void *opaque)
297
{
298
    BlkverifyAIOCB *acb = qemu_aio_get(&blkverify_aiocb_info, bs, cb, opaque);
299

    
300
    acb->bh = NULL;
301
    acb->is_write = is_write;
302
    acb->sector_num = sector_num;
303
    acb->nb_sectors = nb_sectors;
304
    acb->ret = -EINPROGRESS;
305
    acb->done = 0;
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    acb->qiov = qiov;
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    acb->buf = NULL;
308
    acb->verify = NULL;
309
    acb->finished = NULL;
310
    return acb;
311
}
312

    
313
static void blkverify_aio_bh(void *opaque)
314
{
315
    BlkverifyAIOCB *acb = opaque;
316

    
317
    qemu_bh_delete(acb->bh);
318
    if (acb->buf) {
319
        qemu_iovec_destroy(&acb->raw_qiov);
320
        qemu_vfree(acb->buf);
321
    }
322
    acb->common.cb(acb->common.opaque, acb->ret);
323
    if (acb->finished) {
324
        *acb->finished = true;
325
    }
326
    qemu_aio_release(acb);
327
}
328

    
329
static void blkverify_aio_cb(void *opaque, int ret)
330
{
331
    BlkverifyAIOCB *acb = opaque;
332

    
333
    switch (++acb->done) {
334
    case 1:
335
        acb->ret = ret;
336
        break;
337

    
338
    case 2:
339
        if (acb->ret != ret) {
340
            blkverify_err(acb, "return value mismatch %d != %d", acb->ret, ret);
341
        }
342

    
343
        if (acb->verify) {
344
            acb->verify(acb);
345
        }
346

    
347
        acb->bh = qemu_bh_new(blkverify_aio_bh, acb);
348
        qemu_bh_schedule(acb->bh);
349
        break;
350
    }
351
}
352

    
353
static void blkverify_verify_readv(BlkverifyAIOCB *acb)
354
{
355
    ssize_t offset = blkverify_iovec_compare(acb->qiov, &acb->raw_qiov);
356
    if (offset != -1) {
357
        blkverify_err(acb, "contents mismatch in sector %" PRId64,
358
                      acb->sector_num + (int64_t)(offset / BDRV_SECTOR_SIZE));
359
    }
360
}
361

    
362
static BlockDriverAIOCB *blkverify_aio_readv(BlockDriverState *bs,
363
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
364
        BlockDriverCompletionFunc *cb, void *opaque)
365
{
366
    BDRVBlkverifyState *s = bs->opaque;
367
    BlkverifyAIOCB *acb = blkverify_aio_get(bs, false, sector_num, qiov,
368
                                            nb_sectors, cb, opaque);
369

    
370
    acb->verify = blkverify_verify_readv;
371
    acb->buf = qemu_blockalign(bs->file, qiov->size);
372
    qemu_iovec_init(&acb->raw_qiov, acb->qiov->niov);
373
    blkverify_iovec_clone(&acb->raw_qiov, qiov, acb->buf);
374

    
375
    bdrv_aio_readv(s->test_file, sector_num, qiov, nb_sectors,
376
                   blkverify_aio_cb, acb);
377
    bdrv_aio_readv(bs->file, sector_num, &acb->raw_qiov, nb_sectors,
378
                   blkverify_aio_cb, acb);
379
    return &acb->common;
380
}
381

    
382
static BlockDriverAIOCB *blkverify_aio_writev(BlockDriverState *bs,
383
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
384
        BlockDriverCompletionFunc *cb, void *opaque)
385
{
386
    BDRVBlkverifyState *s = bs->opaque;
387
    BlkverifyAIOCB *acb = blkverify_aio_get(bs, true, sector_num, qiov,
388
                                            nb_sectors, cb, opaque);
389

    
390
    bdrv_aio_writev(s->test_file, sector_num, qiov, nb_sectors,
391
                    blkverify_aio_cb, acb);
392
    bdrv_aio_writev(bs->file, sector_num, qiov, nb_sectors,
393
                    blkverify_aio_cb, acb);
394
    return &acb->common;
395
}
396

    
397
static BlockDriverAIOCB *blkverify_aio_flush(BlockDriverState *bs,
398
                                             BlockDriverCompletionFunc *cb,
399
                                             void *opaque)
400
{
401
    BDRVBlkverifyState *s = bs->opaque;
402

    
403
    /* Only flush test file, the raw file is not important */
404
    return bdrv_aio_flush(s->test_file, cb, opaque);
405
}
406

    
407
static BlockDriver bdrv_blkverify = {
408
    .format_name            = "blkverify",
409
    .protocol_name          = "blkverify",
410
    .instance_size          = sizeof(BDRVBlkverifyState),
411

    
412
    .bdrv_parse_filename    = blkverify_parse_filename,
413
    .bdrv_file_open         = blkverify_open,
414
    .bdrv_close             = blkverify_close,
415
    .bdrv_getlength         = blkverify_getlength,
416

    
417
    .bdrv_aio_readv         = blkverify_aio_readv,
418
    .bdrv_aio_writev        = blkverify_aio_writev,
419
    .bdrv_aio_flush         = blkverify_aio_flush,
420
};
421

    
422
static void bdrv_blkverify_init(void)
423
{
424
    bdrv_register(&bdrv_blkverify);
425
}
426

    
427
block_init(bdrv_blkverify_init);