block: Add options QDict to bdrv_open() prototype

It doesn't do anything yet except storing the options QDict in the
BlockDriverState.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 35 insertions, 12 deletions

diff --git a/block.c b/block.c
index 01cee877c5..761ea860a9 100644
--- a/block.c
+++ b/block.c
@@ -788,7 +788,8 @@ int bdrv_open_backing_file(BlockDriverState *bs)
     /* backing files always opened read-only */
     back_flags = bs->open_flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT);
 
-    ret = bdrv_open(bs->backing_hd, backing_filename, back_flags, back_drv);
+    ret = bdrv_open(bs->backing_hd, backing_filename, NULL,
+                    back_flags, back_drv);
     if (ret < 0) {
         bdrv_delete(bs->backing_hd);
         bs->backing_hd = NULL;
@@ -800,15 +801,28 @@ int bdrv_open_backing_file(BlockDriverState *bs)
 
 /*
  * Opens a disk image (raw, qcow2, vmdk, ...)
+ *
+ * options is a QDict of options to pass to the block drivers, or NULL for an
+ * empty set of options. The reference to the QDict belongs to the block layer
+ * after the call (even on failure), so if the caller intends to reuse the
+ * dictionary, it needs to use QINCREF() before calling bdrv_open.
  */
-int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
-              BlockDriver *drv)
+int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
+              int flags, BlockDriver *drv)
 {
     int ret;
     /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
     char tmp_filename[PATH_MAX + 1];
     BlockDriverState *file = NULL;
 
+    /* NULL means an empty set of options */
+    if (options == NULL) {
+        options = qdict_new();
+    }
+
+    bs->options = options;
+
+    /* For snapshot=on, create a temporary qcow2 overlay */
     if (flags & BDRV_O_SNAPSHOT) {
         BlockDriverState *bs1;
         int64_t total_size;
@@ -822,10 +836,10 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
 
         /* if there is a backing file, use it */
         bs1 = bdrv_new("");
-        ret = bdrv_open(bs1, filename, 0, drv);
+        ret = bdrv_open(bs1, filename, NULL, 0, drv);
         if (ret < 0) {
             bdrv_delete(bs1);
-            return ret;
+            goto fail;
         }
         total_size = bdrv_getlength(bs1) & BDRV_SECTOR_MASK;
 
@@ -836,15 +850,17 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
 
         ret = get_tmp_filename(tmp_filename, sizeof(tmp_filename));
         if (ret < 0) {
-            return ret;
+            goto fail;
         }
 
         /* Real path is meaningless for protocols */
-        if (is_protocol)
+        if (is_protocol) {
             snprintf(backing_filename, sizeof(backing_filename),
                      "%s", filename);
-        else if (!realpath(filename, backing_filename))
-            return -errno;
+        } else if (!realpath(filename, backing_filename)) {
+            ret = -errno;
+            goto fail;
+        }
 
         bdrv_qcow2 = bdrv_find_format("qcow2");
         options = parse_option_parameters("", bdrv_qcow2->create_options, NULL);
@@ -859,7 +875,7 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
         ret = bdrv_create(bdrv_qcow2, tmp_filename, options);
         free_option_parameters(options);
         if (ret < 0) {
-            return ret;
+            goto fail;
         }
 
         filename = tmp_filename;
@@ -874,7 +890,7 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
 
     ret = bdrv_file_open(&file, filename, bdrv_open_flags(bs, flags));
     if (ret < 0) {
-        return ret;
+        goto fail;
     }
 
     /* Find the right image format driver */
@@ -924,6 +940,10 @@ unlink_and_fail:
     if (bs->is_temporary) {
         unlink(filename);
     }
+fail:
+    QDECREF(bs->options);
+    bs->options = NULL;
+
     return ret;
 }
 
@@ -1193,6 +1213,8 @@ void bdrv_close(BlockDriverState *bs)
         bs->valid_key = 0;
         bs->sg = 0;
         bs->growable = 0;
+        QDECREF(bs->options);
+        bs->options = NULL;
 
         if (bs->file != NULL) {
             bdrv_delete(bs->file);
@@ -4594,7 +4616,8 @@ void bdrv_img_create(const char *filename, const char *fmt,
 
             bs = bdrv_new("");
 
-            ret = bdrv_open(bs, backing_file->value.s, back_flags, backing_drv);
+            ret = bdrv_open(bs, backing_file->value.s, NULL, back_flags,
+                            backing_drv);
             if (ret < 0) {
                 error_setg_errno(errp, -ret, "Could not open '%s'",
                                  backing_file->value.s);