block: Make essential BlockDriver objects public

There are some block drivers which are essential to QEMU and may not be
removed: These are raw, file and qcow2 (as the default non-raw format).
Make their BlockDriver objects public so they can be directly referenced
throughout the block layer without needing to call bdrv_find_format()
and having to deal with an error at runtime, while the real problem
occurred during linking (where raw, file or qcow2 were not linked into
qemu).

Cc: qemu-stable@nongnu.org
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 192fce8..06a21dd 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -414,6 +414,14 @@ struct BlockDriverState {
     Error *backing_blocker;
 };
 
+
+/* Essential block drivers which must always be statically linked into qemu, and
+ * which therefore can be accessed without using bdrv_find_format() */
+extern BlockDriver bdrv_file;
+extern BlockDriver bdrv_raw;
+extern BlockDriver bdrv_qcow2;
+
+
 int get_tmp_filename(char *filename, int size);
 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
                             const char *filename);