Archipelago » qemu

/*

 * Block protocol for block driver correctness testing

 *

 * Copyright (C) 2010 IBM, Corp.

 *

 * This work is licensed under the terms of the GNU GPL, version 2 or later.

 * See the COPYING file in the top-level directory.

 */

#include <stdarg.h>

#include "qemu_socket.h" /* for EINPROGRESS on Windows */

#include "block_int.h"

typedef struct {

    BlockDriverState *test_file;

} BDRVBlkverifyState;

typedef struct BlkverifyAIOCB BlkverifyAIOCB;

struct BlkverifyAIOCB {

    BlockDriverAIOCB common;

    QEMUBH *bh;

    /* Request metadata */

    bool is_write;

    int64_t sector_num;

    int nb_sectors;

    int ret;                    /* first completed request's result */

    unsigned int done;          /* completion counter */

    bool *finished;             /* completion signal for cancel */

    QEMUIOVector *qiov;         /* user I/O vector */

    QEMUIOVector raw_qiov;      /* cloned I/O vector for raw file */

    void *buf;                  /* buffer for raw file I/O */

    void (*verify)(BlkverifyAIOCB *acb);

};

static void blkverify_aio_cancel(BlockDriverAIOCB *blockacb)

{

    BlkverifyAIOCB *acb = (BlkverifyAIOCB *)blockacb;

    bool finished = false;

    /* Wait until request completes, invokes its callback, and frees itself */

    acb->finished = &finished;

    while (!finished) {

        qemu_aio_wait();

    }

}

static AIOPool blkverify_aio_pool = {

    .aiocb_size         = sizeof(BlkverifyAIOCB),

    .cancel             = blkverify_aio_cancel,

};

static void GCC_FMT_ATTR(2, 3) blkverify_err(BlkverifyAIOCB *acb,

                                             const char *fmt, ...)

{

    va_list ap;

    va_start(ap, fmt);

    fprintf(stderr, "blkverify: %s sector_num=%" PRId64 " nb_sectors=%d ",

            acb->is_write ? "write" : "read", acb->sector_num,

            acb->nb_sectors);

    vfprintf(stderr, fmt, ap);

    fprintf(stderr, "\n");

    va_end(ap);

    exit(1);

}

/* Valid blkverify filenames look like blkverify:path/to/raw_image:path/to/image */

static int blkverify_open(BlockDriverState *bs, const char *filename, int flags)

{

    BDRVBlkverifyState *s = bs->opaque;

    int ret;

    char *raw, *c;

    /* Parse the blkverify: prefix */

    if (strncmp(filename, "blkverify:", strlen("blkverify:"))) {

        return -EINVAL;

    }

    filename += strlen("blkverify:");

    /* Parse the raw image filename */

    c = strchr(filename, ':');

    if (c == NULL) {

        return -EINVAL;

    }

    raw = strdup(filename);

    raw[c - filename] = '\0';

    ret = bdrv_file_open(&bs->file, raw, flags);

    free(raw);

    if (ret < 0) {

        return ret;

    }

    filename = c + 1;

    /* Open the test file */

    s->test_file = bdrv_new("");

    ret = bdrv_open(s->test_file, filename, flags, NULL);

    if (ret < 0) {

        bdrv_delete(s->test_file);

        s->test_file = NULL;

        return ret;

    }

    return 0;

}

static void blkverify_close(BlockDriverState *bs)

{

    BDRVBlkverifyState *s = bs->opaque;

    bdrv_delete(s->test_file);

    s->test_file = NULL;

}

static void blkverify_flush(BlockDriverState *bs)

{

    BDRVBlkverifyState *s = bs->opaque;

    /* Only flush test file, the raw file is not important */

    bdrv_flush(s->test_file);

}

static int64_t blkverify_getlength(BlockDriverState *bs)

{

    BDRVBlkverifyState *s = bs->opaque;

    return bdrv_getlength(s->test_file);

}

/**

 * Check that I/O vector contents are identical

 *

 * @a:          I/O vector

 * @b:          I/O vector

 * @ret:        Offset to first mismatching byte or -1 if match

 */

static ssize_t blkverify_iovec_compare(QEMUIOVector *a, QEMUIOVector *b)

{

    int i;

    ssize_t offset = 0;

    assert(a->niov == b->niov);

    for (i = 0; i < a->niov; i++) {

        size_t len = 0;

        uint8_t *p = (uint8_t *)a->iov[i].iov_base;

        uint8_t *q = (uint8_t *)b->iov[i].iov_base;

        assert(a->iov[i].iov_len == b->iov[i].iov_len);

        while (len < a->iov[i].iov_len && *p++ == *q++) {

            len++;

        }

        offset += len;

        if (len != a->iov[i].iov_len) {

            return offset;

        }

    }

    return -1;

}

typedef struct {

    int src_index;

    struct iovec *src_iov;

    void *dest_base;

} IOVectorSortElem;

static int sortelem_cmp_src_base(const void *a, const void *b)

{

    const IOVectorSortElem *elem_a = a;

    const IOVectorSortElem *elem_b = b;

    /* Don't overflow */

    if (elem_a->src_iov->iov_base < elem_b->src_iov->iov_base) {

        return -1;

    } else if (elem_a->src_iov->iov_base > elem_b->src_iov->iov_base) {

        return 1;

    } else {

        return 0;

    }

}

static int sortelem_cmp_src_index(const void *a, const void *b)

{

    const IOVectorSortElem *elem_a = a;

    const IOVectorSortElem *elem_b = b;

    return elem_a->src_index - elem_b->src_index;

}

/**

 * Copy contents of I/O vector

 *

 * The relative relationships of overlapping iovecs are preserved.  This is

 * necessary to ensure identical semantics in the cloned I/O vector.

 */

static void blkverify_iovec_clone(QEMUIOVector *dest, const QEMUIOVector *src,

                                  void *buf)

{

    IOVectorSortElem sortelems[src->niov];

    void *last_end;

    int i;

    /* Sort by source iovecs by base address */

    for (i = 0; i < src->niov; i++) {

        sortelems[i].src_index = i;

        sortelems[i].src_iov = &src->iov[i];

    }

    qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_base);

    /* Allocate buffer space taking into account overlapping iovecs */

    last_end = NULL;

    for (i = 0; i < src->niov; i++) {

        struct iovec *cur = sortelems[i].src_iov;

        ptrdiff_t rewind = 0;

        /* Detect overlap */

        if (last_end && last_end > cur->iov_base) {

            rewind = last_end - cur->iov_base;

        }

        sortelems[i].dest_base = buf - rewind;

        buf += cur->iov_len - MIN(rewind, cur->iov_len);

        last_end = MAX(cur->iov_base + cur->iov_len, last_end);

    }

    /* Sort by source iovec index and build destination iovec */

    qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_index);

    for (i = 0; i < src->niov; i++) {

        qemu_iovec_add(dest, sortelems[i].dest_base, src->iov[i].iov_len);

    }

}

static BlkverifyAIOCB *blkverify_aio_get(BlockDriverState *bs, bool is_write,

                                         int64_t sector_num, QEMUIOVector *qiov,

                                         int nb_sectors,

                                         BlockDriverCompletionFunc *cb,

                                         void *opaque)

{

    BlkverifyAIOCB *acb = qemu_aio_get(&blkverify_aio_pool, bs, cb, opaque);

    acb->bh = NULL;

    acb->is_write = is_write;

    acb->sector_num = sector_num;

    acb->nb_sectors = nb_sectors;

    acb->ret = -EINPROGRESS;

    acb->done = 0;

    acb->qiov = qiov;

    acb->buf = NULL;

    acb->verify = NULL;

    acb->finished = NULL;

    return acb;

}

static void blkverify_aio_bh(void *opaque)

{

    BlkverifyAIOCB *acb = opaque;

    qemu_bh_delete(acb->bh);

    if (acb->buf) {

        qemu_iovec_destroy(&acb->raw_qiov);

        qemu_vfree(acb->buf);

    }

    acb->common.cb(acb->common.opaque, acb->ret);

    if (acb->finished) {

        *acb->finished = true;

    }

    qemu_aio_release(acb);

}

static void blkverify_aio_cb(void *opaque, int ret)

{

    BlkverifyAIOCB *acb = opaque;

    switch (++acb->done) {

    case 1:

        acb->ret = ret;

        break;

    case 2:

        if (acb->ret != ret) {

            blkverify_err(acb, "return value mismatch %d != %d", acb->ret, ret);

        }

        if (acb->verify) {

            acb->verify(acb);

        }

        acb->bh = qemu_bh_new(blkverify_aio_bh, acb);

        qemu_bh_schedule(acb->bh);

        break;

    }

}

static void blkverify_verify_readv(BlkverifyAIOCB *acb)

{

    ssize_t offset = blkverify_iovec_compare(acb->qiov, &acb->raw_qiov);

    if (offset != -1) {

        blkverify_err(acb, "contents mismatch in sector %lld",

                      acb->sector_num + (offset / BDRV_SECTOR_SIZE));

    }

}

static BlockDriverAIOCB *blkverify_aio_readv(BlockDriverState *bs,

        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,

        BlockDriverCompletionFunc *cb, void *opaque)

{

    BDRVBlkverifyState *s = bs->opaque;

    BlkverifyAIOCB *acb = blkverify_aio_get(bs, false, sector_num, qiov,

                                            nb_sectors, cb, opaque);

    acb->verify = blkverify_verify_readv;

    acb->buf = qemu_blockalign(bs->file, qiov->size);

    qemu_iovec_init(&acb->raw_qiov, acb->qiov->niov);

    blkverify_iovec_clone(&acb->raw_qiov, qiov, acb->buf);

    if (!bdrv_aio_readv(s->test_file, sector_num, qiov, nb_sectors,

                        blkverify_aio_cb, acb)) {

        blkverify_aio_cb(acb, -EIO);

    }

    if (!bdrv_aio_readv(bs->file, sector_num, &acb->raw_qiov, nb_sectors,

                        blkverify_aio_cb, acb)) {

        blkverify_aio_cb(acb, -EIO);

    }

    return &acb->common;

}

static BlockDriverAIOCB *blkverify_aio_writev(BlockDriverState *bs,

        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,

        BlockDriverCompletionFunc *cb, void *opaque)

{

    BDRVBlkverifyState *s = bs->opaque;

    BlkverifyAIOCB *acb = blkverify_aio_get(bs, true, sector_num, qiov,

                                            nb_sectors, cb, opaque);

    if (!bdrv_aio_writev(s->test_file, sector_num, qiov, nb_sectors,

                         blkverify_aio_cb, acb)) {

        blkverify_aio_cb(acb, -EIO);

    }

    if (!bdrv_aio_writev(bs->file, sector_num, qiov, nb_sectors,

                         blkverify_aio_cb, acb)) {

        blkverify_aio_cb(acb, -EIO);

    }

    return &acb->common;

}

static BlockDriverAIOCB *blkverify_aio_flush(BlockDriverState *bs,

                                             BlockDriverCompletionFunc *cb,

                                             void *opaque)

{

    BDRVBlkverifyState *s = bs->opaque;

    /* Only flush test file, the raw file is not important */

    return bdrv_aio_flush(s->test_file, cb, opaque);

}

static BlockDriver bdrv_blkverify = {

    .format_name        = "blkverify",

    .protocol_name      = "blkverify",

    .instance_size      = sizeof(BDRVBlkverifyState),

    .bdrv_getlength     = blkverify_getlength,

    .bdrv_file_open     = blkverify_open,

    .bdrv_close         = blkverify_close,

    .bdrv_flush         = blkverify_flush,

    .bdrv_aio_readv     = blkverify_aio_readv,

    .bdrv_aio_writev    = blkverify_aio_writev,

    .bdrv_aio_flush     = blkverify_aio_flush,

};

static void bdrv_blkverify_init(void)

{

    bdrv_register(&bdrv_blkverify);

}

block_init(bdrv_blkverify_init);