Commit 572b07be authored by Max Reitz's avatar Max Reitz
Browse files

qcow2: Always execute preallocate() in a coroutine 



Some qcow2 functions (at least perform_cow()) expect s->lock to be
taken.  Therefore, if we want to make use of them, we should execute
preallocate() (as "preallocate_co") in a coroutine so that we can use
the qemu_co_mutex_* functions.

Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
Message-id: 20171009215533.12530-3-mreitz@redhat.com
Cc: qemu-stable@nongnu.org
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarJeff Cody <jcody@redhat.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
parent e400ad1e

block/qcow2.c

+34 −7
Original line number Diff line number Diff line
@@ -2460,6 +2460,14 @@ static int qcow2_set_up_encryption(BlockDriverState *bs, const char *encryptfmt, 
}





typedef struct PreallocCo {

    BlockDriverState *bs;

    uint64_t offset;

    uint64_t new_length;



    int ret;

} PreallocCo;



/**

 * Preallocates metadata structures for data clusters between @offset (in the

 * guest disk) and @new_length (which is thus generally the new guest disk
@@ -2467,9 +2475,12 @@ static int qcow2_set_up_encryption(BlockDriverState *bs, const char *encryptfmt, 
 *

 * Returns: 0 on success, -errno on failure.

 */

static int preallocate(BlockDriverState *bs,

                       uint64_t offset, uint64_t new_length)

static void coroutine_fn preallocate_co(void *opaque)

{

    PreallocCo *params = opaque;

    BlockDriverState *bs = params->bs;

    uint64_t offset = params->offset;

    uint64_t new_length = params->new_length;

    BDRVQcow2State *s = bs->opaque;

    uint64_t bytes;

    uint64_t host_offset = 0;
@@ -2477,9 +2488,7 @@ static int preallocate(BlockDriverState *bs, 
    int ret;

    QCowL2Meta *meta;



    if (qemu_in_coroutine()) {

    qemu_co_mutex_lock(&s->lock);

    }



    assert(offset <= new_length);

    bytes = new_length - offset;
@@ -2533,10 +2542,28 @@ static int preallocate(BlockDriverState *bs, 
    ret = 0;



done:

    if (qemu_in_coroutine()) {

    qemu_co_mutex_unlock(&s->lock);

    params->ret = ret;

}

    return ret;



static int preallocate(BlockDriverState *bs,

                       uint64_t offset, uint64_t new_length)

{

    PreallocCo params = {

        .bs         = bs,

        .offset     = offset,

        .new_length = new_length,

        .ret        = -EINPROGRESS,

    };



    if (qemu_in_coroutine()) {

        preallocate_co(&params);

    } else {

        Coroutine *co = qemu_coroutine_create(preallocate_co, &params);

        bdrv_coroutine_enter(bs, co);

        BDRV_POLL_WHILE(bs, params.ret == -EINPROGRESS);

    }

    return params.ret;

}



/* qcow2_refcount_metadata_size: