block: Use common driver selection code for bdrv_open_file()

This moves the bdrv_open_file() call a bit down so that it can use the
bdrv_open() code that selects the right block driver.

The code between the old and the new call site is either common code
(the error message for an unknown driver has been unified now) or
doesn't run with cleared BDRV_O_PROTOCOL (added an if block in one
place, whereas the right path was already asserted in another place)

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>

1 files changed, 30 insertions, 37 deletions

diff --git a/block.c b/block.c
index 0aa444e..97b4ddc 100644
--- a/block.c
+++ b/block.c
@@ -1135,21 +1135,14 @@ static int bdrv_fill_options(QDict **options, const char **pfilename, int flags,
  * returns. Then, the caller is responsible for freeing it. If it intends to
  * reuse the QDict, QINCREF() should be called beforehand.
  */
-static int bdrv_file_open(BlockDriverState *bs, QDict **options, int flags,
-                          Error **errp)
+static int bdrv_file_open(BlockDriverState *bs, BlockDriver *drv,
+                          QDict **options, int flags, Error **errp)
 {
-    BlockDriver *drv;
     const char *filename;
-    const char *drvname;
     Error *local_err = NULL;
     int ret;
 
     filename = qdict_get_try_str(*options, "filename");
-    drvname = qdict_get_str(*options, "driver");
-
-    drv = bdrv_find_format(drvname);
-    assert(drv);
-    qdict_del(*options, "driver");
 
     /* Open the file */
     if (!drv->bdrv_file_open) {
@@ -1452,35 +1445,23 @@ int bdrv_open(BlockDriverState **pbs, const char *filename,
     bs->options = options;
     options = qdict_clone_shallow(options);
 
-    if (flags & BDRV_O_PROTOCOL) {
-        assert(!drv);
-        ret = bdrv_file_open(bs, &options, flags & ~BDRV_O_PROTOCOL,
-                             &local_err);
-        if (!ret) {
-            drv = bs->drv;
-            goto done;
-        } else if (bs->drv) {
-            goto close_and_fail;
-        } else {
-            goto fail;
-        }
-    }
-
     /* Open image file without format layer */
-    if (flags & BDRV_O_RDWR) {
-        flags |= BDRV_O_ALLOW_RDWR;
-    }
-    if (flags & BDRV_O_SNAPSHOT) {
-        snapshot_flags = bdrv_temp_snapshot_flags(flags);
-        flags = bdrv_backing_flags(flags);
-    }
+    if ((flags & BDRV_O_PROTOCOL) == 0) {
+        if (flags & BDRV_O_RDWR) {
+            flags |= BDRV_O_ALLOW_RDWR;
+        }
+        if (flags & BDRV_O_SNAPSHOT) {
+            snapshot_flags = bdrv_temp_snapshot_flags(flags);
+            flags = bdrv_backing_flags(flags);
+        }
 
-    assert(file == NULL);
-    ret = bdrv_open_image(&file, filename, options, "file",
-                          bdrv_inherited_flags(flags),
-                          true, &local_err);
-    if (ret < 0) {
-        goto fail;
+        assert(file == NULL);
+        ret = bdrv_open_image(&file, filename, options, "file",
+                              bdrv_inherited_flags(flags),
+                              true, &local_err);
+        if (ret < 0) {
+            goto fail;
+        }
     }
 
     /* Find the right image format driver */
@@ -1492,7 +1473,7 @@ int bdrv_open(BlockDriverState **pbs, const char *filename,
         drv = bdrv_find_format(drvname);
         qdict_del(options, "driver");
         if (!drv) {
-            error_setg(errp, "Invalid driver: '%s'", drvname);
+            error_setg(errp, "Unknown driver: '%s'", drvname);
             ret = -EINVAL;
             goto fail;
         }
@@ -1508,6 +1489,18 @@ int bdrv_open(BlockDriverState **pbs, const char *filename,
     }
 
     /* Open the image */
+    if (flags & BDRV_O_PROTOCOL) {
+        ret = bdrv_file_open(bs, drv, &options, flags & ~BDRV_O_PROTOCOL,
+                             &local_err);
+        if (!ret) {
+            goto done;
+        } else if (bs->drv) {
+            goto close_and_fail;
+        } else {
+            goto fail;
+        }
+    }
+
     ret = bdrv_open_common(bs, file, options, flags, drv, &local_err);
     if (ret < 0) {
         goto fail;