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Diffstat (limited to 'block.c')
-rw-r--r--block.c36
1 files changed, 25 insertions, 11 deletions
diff --git a/block.c b/block.c
index ba24b8e674..cf5eb34382 100644
--- a/block.c
+++ b/block.c
@@ -687,13 +687,19 @@ int bdrv_parse_cache_flags(const char *mode, int *flags)
}
/*
- * Returns the flags that a temporary snapshot should get, based on the
- * originally requested flags (the originally requested image will have flags
- * like a backing file)
+ * Returns the options and flags that a temporary snapshot should get, based on
+ * the originally requested flags (the originally requested image will have
+ * flags like a backing file)
*/
-static int bdrv_temp_snapshot_flags(int flags)
+static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options,
+ int parent_flags, QDict *parent_options)
{
- return (flags & ~BDRV_O_SNAPSHOT) | BDRV_O_TEMPORARY;
+ *child_flags = (parent_flags & ~BDRV_O_SNAPSHOT) | BDRV_O_TEMPORARY;
+
+ /* For temporary files, unconditional cache=unsafe is fine */
+ qdict_set_default_str(child_options, BDRV_OPT_CACHE_WB, "on");
+ qdict_set_default_str(child_options, BDRV_OPT_CACHE_DIRECT, "off");
+ qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on");
}
/*
@@ -1424,13 +1430,13 @@ done:
return c;
}
-int bdrv_append_temp_snapshot(BlockDriverState *bs, int flags, Error **errp)
+static int bdrv_append_temp_snapshot(BlockDriverState *bs, int flags,
+ QDict *snapshot_options, Error **errp)
{
/* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
char *tmp_filename = g_malloc0(PATH_MAX + 1);
int64_t total_size;
QemuOpts *opts = NULL;
- QDict *snapshot_options;
BlockDriverState *bs_snapshot;
Error *local_err = NULL;
int ret;
@@ -1464,8 +1470,7 @@ int bdrv_append_temp_snapshot(BlockDriverState *bs, int flags, Error **errp)
goto out;
}
- /* Prepare a new options QDict for the temporary file */
- snapshot_options = qdict_new();
+ /* Prepare options QDict for the temporary file */
qdict_put(snapshot_options, "file.driver",
qstring_from_str("file"));
qdict_put(snapshot_options, "file.filename",
@@ -1477,6 +1482,7 @@ int bdrv_append_temp_snapshot(BlockDriverState *bs, int flags, Error **errp)
ret = bdrv_open(&bs_snapshot, NULL, NULL, snapshot_options,
flags, &local_err);
+ snapshot_options = NULL;
if (ret < 0) {
error_propagate(errp, local_err);
goto out;
@@ -1485,6 +1491,7 @@ int bdrv_append_temp_snapshot(BlockDriverState *bs, int flags, Error **errp)
bdrv_append(bs_snapshot, bs);
out:
+ QDECREF(snapshot_options);
g_free(tmp_filename);
return ret;
}
@@ -1516,6 +1523,7 @@ static int bdrv_open_inherit(BlockDriverState **pbs, const char *filename,
const char *drvname;
const char *backing;
Error *local_err = NULL;
+ QDict *snapshot_options = NULL;
int snapshot_flags = 0;
assert(pbs);
@@ -1607,7 +1615,9 @@ static int bdrv_open_inherit(BlockDriverState **pbs, const char *filename,
flags |= BDRV_O_ALLOW_RDWR;
}
if (flags & BDRV_O_SNAPSHOT) {
- snapshot_flags = bdrv_temp_snapshot_flags(flags);
+ snapshot_options = qdict_new();
+ bdrv_temp_snapshot_options(&snapshot_flags, snapshot_options,
+ flags, options);
bdrv_backing_options(&flags, options, flags, options);
}
@@ -1709,7 +1719,9 @@ static int bdrv_open_inherit(BlockDriverState **pbs, const char *filename,
/* For snapshot=on, create a temporary qcow2 overlay. bs points to the
* temporary snapshot afterwards. */
if (snapshot_flags) {
- ret = bdrv_append_temp_snapshot(bs, snapshot_flags, &local_err);
+ ret = bdrv_append_temp_snapshot(bs, snapshot_flags, snapshot_options,
+ &local_err);
+ snapshot_options = NULL;
if (local_err) {
goto close_and_fail;
}
@@ -1721,6 +1733,7 @@ fail:
if (file != NULL) {
bdrv_unref_child(bs, file);
}
+ QDECREF(snapshot_options);
QDECREF(bs->explicit_options);
QDECREF(bs->options);
QDECREF(options);
@@ -1743,6 +1756,7 @@ close_and_fail:
} else {
bdrv_unref(bs);
}
+ QDECREF(snapshot_options);
QDECREF(options);
if (local_err) {
error_propagate(errp, local_err);