Commit 74c4510a authored by Kevin Wolf's avatar Kevin Wolf Committed by Stefan Hajnoczi
Browse files

qcow2: Allow lazy refcounts to be enabled on the command line 



qcow2 images now accept a boolean lazy_refcounts options. Use it like
this:

  -drive file=test.qcow2,lazy_refcounts=on

If the option is specified on the command line, it overrides the default
specified by the qcow2 header flags that were set when creating the
image.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 0006383e

block/qcow2-cluster.c

+1 −1
Original line number Diff line number Diff line
@@ -668,7 +668,7 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m) 
    }



    /* Update L2 table. */

    if (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS) {

    if (s->use_lazy_refcounts) {

        qcow2_mark_dirty(bs);

    }

    if (qcow2_need_accurate_refcounts(s)) {

block/qcow2.c

+37 −0
Original line number Diff line number Diff line
@@ -285,11 +285,26 @@ static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result, 
    return ret;

}



static QemuOptsList qcow2_runtime_opts = {

    .name = "qcow2",

    .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head),

    .desc = {

        {

            .name = "lazy_refcounts",

            .type = QEMU_OPT_BOOL,

            .help = "Postpone refcount updates",

        },

        { /* end of list */ }

    },

};



static int qcow2_open(BlockDriverState *bs, QDict *options, int flags)

{

    BDRVQcowState *s = bs->opaque;

    int len, i, ret = 0;

    QCowHeader header;

    QemuOpts *opts;

    Error *local_err = NULL;

    uint64_t ext_end;



    ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
@@ -495,6 +510,28 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags) 
        }

    }



    /* Enable lazy_refcounts according to image and command line options */

    opts = qemu_opts_create_nofail(&qcow2_runtime_opts);

    qemu_opts_absorb_qdict(opts, options, &local_err);

    if (error_is_set(&local_err)) {

        qerror_report_err(local_err);

        error_free(local_err);

        ret = -EINVAL;

        goto fail;

    }



    s->use_lazy_refcounts = qemu_opt_get_bool(opts, "lazy_refcounts",

        (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS));



    qemu_opts_del(opts);



    if (s->use_lazy_refcounts && s->qcow_version < 3) {

        qerror_report(ERROR_CLASS_GENERIC_ERROR, "Lazy refcounts require "

            "a qcow2 image with at least qemu 1.1 compatibility level");

        ret = -EINVAL;

        goto fail;

    }



#ifdef DEBUG_ALLOC

    {

        BdrvCheckResult result = {0};

block/qcow2.h

+1 −0
Original line number Diff line number Diff line
@@ -173,6 +173,7 @@ typedef struct BDRVQcowState { 


    int flags;

    int qcow_version;

    bool use_lazy_refcounts;



    uint64_t incompatible_features;

    uint64_t compatible_features;