block: Change BDS parameter of bdrv_open() to **
Make bdrv_open() take a pointer to a BDS pointer, similarly to
bdrv_file_open(). If a pointer to a NULL pointer is given, bdrv_open()
will create a new BDS with an empty name; if the BDS pointer is not
NULL, that existing BDS will be reused (in the same way as bdrv_open()
already did).
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index 034e1ab..c39bd3d 100644
--- a/block.c
+++ b/block.c
@@ -1046,7 +1046,7 @@
}
if (!drv->bdrv_file_open) {
- ret = bdrv_open(bs, filename, options, flags, drv, &local_err);
+ ret = bdrv_open(&bs, filename, options, flags, drv, &local_err);
options = NULL;
} else {
ret = bdrv_open_common(bs, NULL, options, flags, drv, &local_err);
@@ -1115,8 +1115,6 @@
sizeof(backing_filename));
}
- bs->backing_hd = bdrv_new("");
-
if (bs->backing_format[0] != '\0') {
back_drv = bdrv_find_format(bs->backing_format);
}
@@ -1125,11 +1123,11 @@
back_flags = bs->open_flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT |
BDRV_O_COPY_ON_READ);
- ret = bdrv_open(bs->backing_hd,
+ assert(bs->backing_hd == NULL);
+ ret = bdrv_open(&bs->backing_hd,
*backing_filename ? backing_filename : NULL, options,
back_flags, back_drv, &local_err);
if (ret < 0) {
- bdrv_unref(bs->backing_hd);
bs->backing_hd = NULL;
bs->open_flags |= BDRV_O_NO_BACKING;
error_setg(errp, "Could not open backing file: %s",
@@ -1166,6 +1164,8 @@
* BlockdevRef.
*
* The BlockdevRef will be removed from the options QDict.
+ *
+ * To conform with the behavior of bdrv_open(), *pbs has to be NULL.
*/
int bdrv_open_image(BlockDriverState **pbs, const char *filename,
QDict *options, const char *bdref_key, int flags,
@@ -1176,6 +1176,9 @@
char *bdref_key_dot;
const char *reference;
+ assert(pbs);
+ assert(*pbs == NULL);
+
bdref_key_dot = g_strdup_printf("%s.", bdref_key);
qdict_extract_subqdict(options, &image_options, bdref_key_dot);
g_free(bdref_key_dot);
@@ -1196,8 +1199,6 @@
/* If a filename is given and the block driver should be detected
automatically (instead of using none), use bdrv_open() in order to do
that auto-detection. */
- BlockDriverState *bs;
-
if (reference) {
error_setg(errp, "Cannot reference an existing block device while "
"giving a filename");
@@ -1205,13 +1206,7 @@
goto done;
}
- bs = bdrv_new("");
- ret = bdrv_open(bs, filename, image_options, flags, NULL, errp);
- if (ret < 0) {
- bdrv_unref(bs);
- } else {
- *pbs = bs;
- }
+ ret = bdrv_open(pbs, filename, image_options, flags, NULL, errp);
} else {
ret = bdrv_file_open(pbs, filename, reference, image_options, flags,
errp);
@@ -1229,17 +1224,28 @@
* 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.
+ *
+ * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
+ * If it is not NULL, the referenced BDS will be reused.
*/
-int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
+int bdrv_open(BlockDriverState **pbs, const char *filename, QDict *options,
int flags, BlockDriver *drv, Error **errp)
{
int ret;
/* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
char tmp_filename[PATH_MAX + 1];
- BlockDriverState *file = NULL;
+ BlockDriverState *file = NULL, *bs;
const char *drvname;
Error *local_err = NULL;
+ assert(pbs);
+
+ if (*pbs) {
+ bs = *pbs;
+ } else {
+ bs = bdrv_new("");
+ }
+
/* NULL means an empty set of options */
if (options == NULL) {
options = qdict_new();
@@ -1260,12 +1266,11 @@
instead of opening 'filename' directly */
/* Get the required size from the image */
- bs1 = bdrv_new("");
QINCREF(options);
- ret = bdrv_open(bs1, filename, options, BDRV_O_NO_BACKING,
+ bs1 = NULL;
+ ret = bdrv_open(&bs1, filename, options, BDRV_O_NO_BACKING,
drv, &local_err);
if (ret < 0) {
- bdrv_unref(bs1);
goto fail;
}
total_size = bdrv_getlength(bs1) & BDRV_SECTOR_MASK;
@@ -1322,6 +1327,7 @@
flags |= BDRV_O_ALLOW_RDWR;
}
+ assert(file == NULL);
ret = bdrv_open_image(&file, filename, options, "file",
bdrv_open_flags(bs, flags | BDRV_O_UNMAP), true, true,
&local_err);
@@ -1393,6 +1399,7 @@
bdrv_dev_change_media_cb(bs, true);
}
+ *pbs = bs;
return 0;
unlink_and_fail:
@@ -1406,13 +1413,24 @@
QDECREF(bs->options);
QDECREF(options);
bs->options = NULL;
+ if (!*pbs) {
+ /* If *pbs is NULL, a new BDS has been created in this function and
+ needs to be freed now. Otherwise, it does not need to be closed,
+ since it has not really been opened yet. */
+ bdrv_unref(bs);
+ }
if (local_err) {
error_propagate(errp, local_err);
}
return ret;
close_and_fail:
- bdrv_close(bs);
+ /* See fail path, but now the BDS has to be always closed */
+ if (*pbs) {
+ bdrv_close(bs);
+ } else {
+ bdrv_unref(bs);
+ }
QDECREF(options);
if (local_err) {
error_propagate(errp, local_err);
@@ -5290,9 +5308,8 @@
back_flags =
flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
- bs = bdrv_new("");
-
- ret = bdrv_open(bs, backing_file->value.s, NULL, back_flags,
+ bs = NULL;
+ ret = bdrv_open(&bs, backing_file->value.s, NULL, back_flags,
backing_drv, &local_err);
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not open '%s': %s",
@@ -5300,7 +5317,6 @@
error_get_pretty(local_err));
error_free(local_err);
local_err = NULL;
- bdrv_unref(bs);
goto out;
}
bdrv_get_geometry(bs, &size);
