preallocate() is and will be called only from places that do not 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: Max Reitz <mre...@redhat.com> --- block/qcow2.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index df953aa..a8223a0 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -2045,12 +2045,17 @@ static int qcow2_change_backing_file(BlockDriverState *bs, 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; @@ -2059,7 +2064,7 @@ 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) { @@ -2069,7 +2074,7 @@ 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 @@ -2096,11 +2101,17 @@ 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: @@ -2389,10 +2400,7 @@ 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; -- 2.9.4