Commit 5396234b authored by Vladimir Sementsov-Ogievskiy's avatar Vladimir Sementsov-Ogievskiy Committed by Stefan Hajnoczi
Browse files

block/qcow2: implement .bdrv_co_pwritev(_compressed)_part 



Implement and use new interface to get rid of hd_qiov.

Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190604161514.262241-13-vsementsov@virtuozzo.com
Message-Id: <20190604161514.262241-13-vsementsov@virtuozzo.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent df893d25

block/qcow2-cluster.c

+6 −3
Original line number Diff line number Diff line
@@ -829,7 +829,6 @@ static int perform_cow(BlockDriverState *bs, QCowL2Meta *m) 
    assert(start->nb_bytes <= UINT_MAX - end->nb_bytes);

    assert(start->nb_bytes + end->nb_bytes <= UINT_MAX - data_bytes);

    assert(start->offset + start->nb_bytes <= end->offset);

    assert(!m->data_qiov || m->data_qiov->size == data_bytes);



    if ((start->nb_bytes == 0 && end->nb_bytes == 0) || m->skip_cow) {

        return 0;
@@ -861,7 +860,11 @@ static int perform_cow(BlockDriverState *bs, QCowL2Meta *m) 
    /* The part of the buffer where the end region is located */

    end_buffer = start_buffer + buffer_size - end->nb_bytes;



    qemu_iovec_init(&qiov, 2 + (m->data_qiov ? m->data_qiov->niov : 0));

    qemu_iovec_init(&qiov, 2 + (m->data_qiov ?

                                qemu_iovec_subvec_niov(m->data_qiov,

                                                       m->data_qiov_offset,

                                                       data_bytes)

                                : 0));



    qemu_co_mutex_unlock(&s->lock);

    /* First we read the existing data from both COW regions. We
@@ -904,7 +907,7 @@ static int perform_cow(BlockDriverState *bs, QCowL2Meta *m) 
        if (start->nb_bytes) {

            qemu_iovec_add(&qiov, start_buffer, start->nb_bytes);

        }

        qemu_iovec_concat(&qiov, m->data_qiov, 0, data_bytes);

        qemu_iovec_concat(&qiov, m->data_qiov, m->data_qiov_offset, data_bytes);

        if (end->nb_bytes) {

            qemu_iovec_add(&qiov, end_buffer, end->nb_bytes);

        }

block/qcow2.c

+30 −30
Original line number Diff line number Diff line
@@ -2103,7 +2103,8 @@ fail: 
/* Check if it's possible to merge a write request with the writing of

 * the data from the COW regions */

static bool merge_cow(uint64_t offset, unsigned bytes,

                      QEMUIOVector *hd_qiov, QCowL2Meta *l2meta)

                      QEMUIOVector *qiov, size_t qiov_offset,

                      QCowL2Meta *l2meta)

{

    QCowL2Meta *m;
@@ -2132,11 +2133,12 @@ static bool merge_cow(uint64_t offset, unsigned bytes, 


        /* Make sure that adding both COW regions to the QEMUIOVector

         * does not exceed IOV_MAX */

        if (hd_qiov->niov > IOV_MAX - 2) {

        if (qemu_iovec_subvec_niov(qiov, qiov_offset, bytes) > IOV_MAX - 2) {

            continue;

        }



        m->data_qiov = hd_qiov;

        m->data_qiov = qiov;

        m->data_qiov_offset = qiov_offset;

        return true;

    }
@@ -2218,24 +2220,22 @@ static int handle_alloc_space(BlockDriverState *bs, QCowL2Meta *l2meta) 
    return 0;

}



static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,

                                         uint64_t bytes, QEMUIOVector *qiov,

                                         int flags)

static coroutine_fn int qcow2_co_pwritev_part(

        BlockDriverState *bs, uint64_t offset, uint64_t bytes,

        QEMUIOVector *qiov, size_t qiov_offset, int flags)

{

    BDRVQcow2State *s = bs->opaque;

    int offset_in_cluster;

    int ret;

    unsigned int cur_bytes; /* number of sectors in current iteration */

    uint64_t cluster_offset;

    QEMUIOVector hd_qiov;

    QEMUIOVector encrypted_qiov;

    uint64_t bytes_done = 0;

    uint8_t *cluster_data = NULL;

    QCowL2Meta *l2meta = NULL;



    trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes);



    qemu_iovec_init(&hd_qiov, qiov->niov);



    qemu_co_mutex_lock(&s->lock);



    while (bytes != 0) {
@@ -2268,9 +2268,6 @@ static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset, 


        qemu_co_mutex_unlock(&s->lock);



        qemu_iovec_reset(&hd_qiov);

        qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes);



        if (bs->encrypted) {

            assert(s->crypto);

            if (!cluster_data) {
@@ -2283,9 +2280,9 @@ static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset, 
                }

            }



            assert(hd_qiov.size <=

                   QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);

            qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size);

            assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);

            qemu_iovec_to_buf(qiov, qiov_offset + bytes_done,

                              cluster_data, cur_bytes);



            if (qcow2_co_encrypt(bs, cluster_offset, offset,

                                 cluster_data, cur_bytes) < 0) {
@@ -2293,8 +2290,7 @@ static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset, 
                goto out_unlocked;

            }



            qemu_iovec_reset(&hd_qiov);

            qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes);

            qemu_iovec_init_buf(&encrypted_qiov, cluster_data, cur_bytes);

        }



        /* Try to efficiently initialize the physical space with zeroes */
@@ -2307,13 +2303,17 @@ static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset, 
         * writing of the guest data together with that of the COW regions.

         * If it's not possible (or not necessary) then write the

         * guest data now. */

        if (!merge_cow(offset, cur_bytes, &hd_qiov, l2meta)) {

        if (!merge_cow(offset, cur_bytes,

                       bs->encrypted ? &encrypted_qiov : qiov,

                       bs->encrypted ? 0 : qiov_offset + bytes_done, l2meta))

        {

            BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);

            trace_qcow2_writev_data(qemu_coroutine_self(),

                                    cluster_offset + offset_in_cluster);

            ret = bdrv_co_pwritev(s->data_file,

                                  cluster_offset + offset_in_cluster,

                                  cur_bytes, &hd_qiov, 0);

            ret = bdrv_co_pwritev_part(

                    s->data_file, cluster_offset + offset_in_cluster, cur_bytes,

                    bs->encrypted ? &encrypted_qiov : qiov,

                    bs->encrypted ? 0 : qiov_offset + bytes_done, 0);

            if (ret < 0) {

                goto out_unlocked;

            }
@@ -2342,7 +2342,6 @@ out_locked: 


    qemu_co_mutex_unlock(&s->lock);



    qemu_iovec_destroy(&hd_qiov);

    qemu_vfree(cluster_data);

    trace_qcow2_writev_done_req(qemu_coroutine_self(), ret);
@@ -4007,8 +4006,9 @@ fail: 
/* XXX: put compressed sectors first, then all the cluster aligned

   tables to avoid losing bytes in alignment */

static coroutine_fn int

qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,

                            uint64_t bytes, QEMUIOVector *qiov)

qcow2_co_pwritev_compressed_part(BlockDriverState *bs,

                                 uint64_t offset, uint64_t bytes,

                                 QEMUIOVector *qiov, size_t qiov_offset)

{

    BDRVQcow2State *s = bs->opaque;

    int ret;
@@ -4045,7 +4045,7 @@ qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 
        /* Zero-pad last write if image size is not cluster aligned */

        memset(buf + bytes, 0, s->cluster_size - bytes);

    }

    qemu_iovec_to_buf(qiov, 0, buf, bytes);

    qemu_iovec_to_buf(qiov, qiov_offset, buf, bytes);



    out_buf = g_malloc(s->cluster_size);
@@ -4053,7 +4053,7 @@ qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 
                                buf, s->cluster_size);

    if (out_len == -ENOMEM) {

        /* could not compress: write normal cluster */

        ret = qcow2_co_pwritev(bs, offset, bytes, qiov, 0);

        ret = qcow2_co_pwritev_part(bs, offset, bytes, qiov, qiov_offset, 0);

        if (ret < 0) {

            goto fail;

        }
@@ -4664,8 +4664,8 @@ static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 
    BDRVQcow2State *s = bs->opaque;



    BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE);

    return bs->drv->bdrv_co_pwritev(bs, qcow2_vm_state_offset(s) + pos,

                                    qiov->size, qiov, 0);

    return bs->drv->bdrv_co_pwritev_part(bs, qcow2_vm_state_offset(s) + pos,

                                         qiov->size, qiov, 0, 0);

}



static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
@@ -5218,7 +5218,7 @@ BlockDriver bdrv_qcow2 = { 
    .bdrv_co_block_status = qcow2_co_block_status,



    .bdrv_co_preadv_part    = qcow2_co_preadv_part,

    .bdrv_co_pwritev        = qcow2_co_pwritev,

    .bdrv_co_pwritev_part   = qcow2_co_pwritev_part,

    .bdrv_co_flush_to_os    = qcow2_co_flush_to_os,



    .bdrv_co_pwrite_zeroes  = qcow2_co_pwrite_zeroes,
@@ -5226,7 +5226,7 @@ BlockDriver bdrv_qcow2 = { 
    .bdrv_co_copy_range_from = qcow2_co_copy_range_from,

    .bdrv_co_copy_range_to  = qcow2_co_copy_range_to,

    .bdrv_co_truncate       = qcow2_co_truncate,

    .bdrv_co_pwritev_compressed = qcow2_co_pwritev_compressed,

    .bdrv_co_pwritev_compressed_part = qcow2_co_pwritev_compressed_part,

    .bdrv_make_empty        = qcow2_make_empty,



    .bdrv_snapshot_create   = qcow2_snapshot_create,

block/qcow2.h

+1 −0
Original line number Diff line number Diff line
@@ -420,6 +420,7 @@ typedef struct QCowL2Meta 
     * from @cow_start and @cow_end into one single write operation.

     */

    QEMUIOVector *data_qiov;

    size_t data_qiov_offset;



    /** Pointer to next L2Meta of the same write request */

    struct QCowL2Meta *next;

include/qemu/iov.h

+1 −0
Original line number Diff line number Diff line
@@ -206,6 +206,7 @@ void qemu_iovec_init_extended( 
        void *tail_buf, size_t tail_len);

void qemu_iovec_init_slice(QEMUIOVector *qiov, QEMUIOVector *source,

                           size_t offset, size_t len);

int qemu_iovec_subvec_niov(QEMUIOVector *qiov, size_t offset, size_t len);

void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len);

void qemu_iovec_concat(QEMUIOVector *dst,

                       QEMUIOVector *src, size_t soffset, size_t sbytes);

util/iov.c

+10 −0
Original line number Diff line number Diff line
@@ -401,6 +401,16 @@ static struct iovec *qiov_slice(QEMUIOVector *qiov, 
    return iov;

}



int qemu_iovec_subvec_niov(QEMUIOVector *qiov, size_t offset, size_t len)

{

    size_t head, tail;

    int niov;



    qiov_slice(qiov, offset, len, &head, &tail, &niov);



    return niov;

}



/*

 * Compile new iovec, combining @head_buf buffer, sub-qiov of @mid_qiov,

 * and @tail_buf buffer into new qiov.