Commit 652fecd0 authored by Max Reitz's avatar Max Reitz
Browse files

block/qcow2: Lock s->lock in preallocate() 



preallocate() is and will be called only from places that do not
otherwise need to lock s->lock: Currently that is qcow2_create2(), as of
a future patch it will be called from qcow2_truncate(), too.

It therefore makes sense to move locking that mutex into preallocate()
itself.

Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170613202107.10125-11-mreitz@redhat.com
Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
parent 7bc45dc1

block/qcow2.c

+15 −7
Original line number Diff line number Diff line
@@ -2486,12 +2486,17 @@ static int qcow2_set_up_encryption(BlockDriverState *bs, const char *encryptfmt, 
static int preallocate(BlockDriverState *bs,

                       uint64_t offset, uint64_t new_length)

{

    BDRVQcow2State *s = bs->opaque;

    uint64_t bytes;

    uint64_t host_offset = 0;

    unsigned int cur_bytes;

    int ret;

    QCowL2Meta *meta;



    if (qemu_in_coroutine()) {

        qemu_co_mutex_lock(&s->lock);

    }



    assert(offset <= new_length);

    bytes = new_length - offset;
@@ -2500,7 +2505,7 @@ static int preallocate(BlockDriverState *bs, 
        ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes,

                                         &host_offset, &meta);

        if (ret < 0) {

            return ret;

            goto done;

        }



        while (meta) {
@@ -2510,7 +2515,7 @@ static int preallocate(BlockDriverState *bs, 
            if (ret < 0) {

                qcow2_free_any_clusters(bs, meta->alloc_offset,

                                        meta->nb_clusters, QCOW2_DISCARD_NEVER);

                return ret;

                goto done;

            }



            /* There are no dependent requests, but we need to remove our
@@ -2537,11 +2542,17 @@ static int preallocate(BlockDriverState *bs, 
        ret = bdrv_pwrite(bs->file, (host_offset + cur_bytes) - 1,

                          &data, 1);

        if (ret < 0) {

            return ret;

            goto done;

        }

    }



    return 0;

    ret = 0;



done:

    if (qemu_in_coroutine()) {

        qemu_co_mutex_unlock(&s->lock);

    }

    return ret;

}



/* qcow2_refcount_metadata_size:
@@ -2835,10 +2846,7 @@ static int qcow2_create2(const char *filename, int64_t total_size, 


    /* And if we're supposed to preallocate metadata, do that now */

    if (prealloc != PREALLOC_MODE_OFF) {

        BDRVQcow2State *s = blk_bs(blk)->opaque;

        qemu_co_mutex_lock(&s->lock);

        ret = preallocate(blk_bs(blk), 0, total_size);

        qemu_co_mutex_unlock(&s->lock);

        if (ret < 0) {

            error_setg_errno(errp, -ret, "Could not preallocate metadata");

            goto out;