Commit 060bee89 authored by Kevin Wolf's avatar Kevin Wolf
Browse files

qcow2: Drop l2meta.cluster_offset 



There's no real reason to have an l2meta for normal requests that don't
allocate anything. Before we can get rid of it, we must return the host
cluster offset in a different way.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent cf5c1a23

block/qcow2-cluster.c

+6 −4
Original line number Diff line number Diff line
@@ -856,7 +856,7 @@ static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset, 
 * Return 0 on success and -errno in error cases

 */

int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,

    int n_start, int n_end, int *num, QCowL2Meta *m)

    int n_start, int n_end, int *num, uint64_t *host_offset, QCowL2Meta *m)

{

    BDRVQcowState *s = bs->opaque;

    int l2_index, ret, sectors;
@@ -929,7 +929,6 @@ again: 


    /* If there is something left to allocate, do that now */

    *m = (QCowL2Meta) {

        .cluster_offset     = cluster_offset,

        .nb_clusters        = 0,

    };

    qemu_co_queue_init(&m->dependent_requests);
@@ -977,9 +976,11 @@ again: 
            int alloc_n_start = keep_clusters == 0 ? n_start : 0;

            int nb_sectors = MIN(requested_sectors, avail_sectors);



            if (keep_clusters == 0) {

                cluster_offset = alloc_cluster_offset;

            }



            *m = (QCowL2Meta) {

                .cluster_offset = keep_clusters == 0 ?

                                  alloc_cluster_offset : cluster_offset,

                .alloc_offset   = alloc_cluster_offset,

                .offset         = alloc_offset & ~(s->cluster_size - 1),

                .nb_clusters    = nb_clusters,
@@ -1007,6 +1008,7 @@ again: 


    assert(sectors > n_start);

    *num = sectors - n_start;

    *host_offset = cluster_offset;



    return 0;

block/qcow2.c

+7 −7
Original line number Diff line number Diff line
@@ -799,7 +799,7 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs, 
        }



        ret = qcow2_alloc_cluster_offset(bs, sector_num << 9,

            index_in_cluster, n_end, &cur_nr_sectors, l2meta);

            index_in_cluster, n_end, &cur_nr_sectors, &cluster_offset, l2meta);

        if (ret < 0) {

            goto fail;

        }
@@ -809,7 +809,6 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs, 
            qcow2_mark_dirty(bs);

        }



        cluster_offset = l2meta->cluster_offset;

        assert((cluster_offset & 511) == 0);



        qemu_iovec_reset(&hd_qiov);
@@ -1132,6 +1131,7 @@ static int preallocate(BlockDriverState *bs) 
{

    uint64_t nb_sectors;

    uint64_t offset;

    uint64_t host_offset = 0;

    int num;

    int ret;

    QCowL2Meta meta;
@@ -1139,18 +1139,18 @@ static int preallocate(BlockDriverState *bs) 
    nb_sectors = bdrv_getlength(bs) >> 9;

    offset = 0;

    qemu_co_queue_init(&meta.dependent_requests);

    meta.cluster_offset = 0;



    while (nb_sectors) {

        num = MIN(nb_sectors, INT_MAX >> 9);

        ret = qcow2_alloc_cluster_offset(bs, offset, 0, num, &num, &meta);

        ret = qcow2_alloc_cluster_offset(bs, offset, 0, num, &num,

                                         &host_offset, &meta);

        if (ret < 0) {

            return ret;

        }



        ret = qcow2_alloc_cluster_link_l2(bs, &meta);

        if (ret < 0) {

            qcow2_free_any_clusters(bs, meta.cluster_offset, meta.nb_clusters);

            qcow2_free_any_clusters(bs, meta.alloc_offset, meta.nb_clusters);

            return ret;

        }
@@ -1169,10 +1169,10 @@ static int preallocate(BlockDriverState *bs) 
     * all of the allocated clusters (otherwise we get failing reads after

     * EOF). Extend the image to the last allocated sector.

     */

    if (meta.cluster_offset != 0) {

    if (host_offset != 0) {

        uint8_t buf[512];

        memset(buf, 0, 512);

        ret = bdrv_write(bs->file, (meta.cluster_offset >> 9) + num - 1, buf, 1);

        ret = bdrv_write(bs->file, (host_offset >> 9) + num - 1, buf, 1);

        if (ret < 0) {

            return ret;

        }

block/qcow2.h

+1 −4
Original line number Diff line number Diff line
@@ -213,9 +213,6 @@ typedef struct QCowL2Meta 
    /** Guest offset of the first newly allocated cluster */

    uint64_t offset;



    /** Host offset of the first cluster of the request */

    uint64_t cluster_offset;



    /** Host offset of the first newly allocated cluster */

    uint64_t alloc_offset;
@@ -336,7 +333,7 @@ void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 
int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,

    int *num, uint64_t *cluster_offset);

int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,

    int n_start, int n_end, int *num, QCowL2Meta *m);

    int n_start, int n_end, int *num, uint64_t *host_offset, QCowL2Meta *m);

uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,

                                         uint64_t offset,

                                         int compressed_size);