We can keep the logic for child_file, child_format, and child_backing in
a single function and differentiate based on the BdrvChildRole.
Signed-off-by: Max Reitz <mre...@redhat.com>
---
block.c | 96 +++++++++++++++++++++++++++++++++++----------------------
1 file changed, 60 insertions(+), 36 deletions(-)
diff --git a/block.c b/block.c
index f42682478e..b3decde6c5 100644
--- a/block.c
+++ b/block.c
@@ -977,8 +977,8 @@ static void bdrv_temp_snapshot_options(int *child_flags,
QDict *child_options,
}
/*
- * Returns the options and flags that bs->file should get if a protocol driver
- * is expected, based on the given options and flags for the parent BDS
+ * Returns the options and flags that a generic child of a BDS should
+ * get, based on the given options and flags for the parent BDS.
*/
static void bdrv_inherited_options(BdrvChildRole role,
int *child_flags, QDict *child_options,
@@ -986,8 +986,16 @@ static void bdrv_inherited_options(BdrvChildRole role,
{
int flags = parent_flags;
- /* Enable protocol handling, disable format probing for bs->file */
- flags |= BDRV_O_PROTOCOL;
+ assert((role & (BDRV_CHILD_PROTOCOL | BDRV_CHILD_FORMAT))
+ != (BDRV_CHILD_PROTOCOL | BDRV_CHILD_FORMAT));
+
+ if (role & BDRV_CHILD_PROTOCOL) {
+ /* Enable protocol handling, disable format probing */
+ flags |= BDRV_O_PROTOCOL;
+ } else if (role & BDRV_CHILD_FORMAT) {
+ /* Enable format handling */
+ flags &= ~BDRV_O_PROTOCOL;
+ }
/* If the cache mode isn't explicitly set, inherit direct and no-flush from
* the parent. */
@@ -995,26 +1003,57 @@ static void bdrv_inherited_options(BdrvChildRole role,
qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE);
- /* Inherit the read-only option from the parent if it's not set */
- qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
- qdict_copy_default(child_options, parent_options, BDRV_OPT_AUTO_READ_ONLY);
+ if (role & BDRV_CHILD_COW) {
+ /* backing files always opened read-only */
+ qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on");
+ qdict_set_default_str(child_options, BDRV_OPT_AUTO_READ_ONLY, "off");
+ } else {
+ /* Inherit the read-only option from the parent if it's not set */
+ qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
+ qdict_copy_default(child_options, parent_options,
+ BDRV_OPT_AUTO_READ_ONLY);
+ }
- /* Our block drivers take care to send flushes and respect unmap policy,
- * so we can default to enable both on lower layers regardless of the
- * corresponding parent options. */
- qdict_set_default_str(child_options, BDRV_OPT_DISCARD, "unmap");
+ if (role & BDRV_CHILD_PROTOCOL) {
+ /*
+ * Our format drivers (which expect protocol children underneath, hence
+ * the condition) take care to send flushes and respect unmap policy,
so
+ * we can default to enable both on lower layers regardless of the
+ * corresponding parent options.
+ */
+ qdict_set_default_str(child_options, BDRV_OPT_DISCARD, "unmap");
+ }
/* Clear flags that only apply to the top layer */
- flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ |
- BDRV_O_NO_IO);
+ flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ);
+
+ if (role & BDRV_CHILD_METADATA) {
+ flags &= ~BDRV_O_NO_IO;
+ }
+ if (role & BDRV_CHILD_COW) {
+ flags &= ~BDRV_O_TEMPORARY;
+ }
*child_flags = flags;
}
+/*
+ * Returns the options and flags that bs->file should get if a protocol driver
+ * is expected, based on the given options and flags for the parent BDS
+ */
+static void bdrv_inherited_file_options(BdrvChildRole role,
+ int *child_flags, QDict *child_options,
+ int parent_flags, QDict
*parent_options)
+{
+ bdrv_inherited_options(BDRV_CHILD_IMAGE,
+ child_flags, child_options,
+ parent_flags, parent_options);
+}
+
const BdrvChildClass child_file = {
.parent_is_bds = true,
.get_parent_desc = bdrv_child_get_parent_desc,
- .inherit_options = bdrv_inherited_options,
+ .inherit_options = bdrv_inherited_file_options,
.drained_begin = bdrv_child_cb_drained_begin,
.drained_poll = bdrv_child_cb_drained_poll,
.drained_end = bdrv_child_cb_drained_end,
@@ -1034,10 +1073,9 @@ static void bdrv_inherited_fmt_options(BdrvChildRole
role,
int *child_flags, QDict *child_options,
int parent_flags, QDict *parent_options)
{
- child_file.inherit_options(role, child_flags, child_options,
- parent_flags, parent_options);
-
- *child_flags &= ~BDRV_O_PROTOCOL;
+ bdrv_inherited_options(BDRV_CHILD_DATA | BDRV_CHILD_FORMAT,
+ child_flags, child_options,
+ parent_flags, parent_options);
}
const BdrvChildClass child_format = {
@@ -1119,23 +1157,9 @@ static void bdrv_backing_options(BdrvChildRole role,
int *child_flags, QDict *child_options,
int parent_flags, QDict *parent_options)
{
- int flags = parent_flags;
-
- /* The cache mode is inherited unmodified for backing files; except WCE,
- * which is only applied on the top level (BlockBackend) */
- qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
- qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
- qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE);
-
- /* backing files always opened read-only */
- qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on");
- qdict_set_default_str(child_options, BDRV_OPT_AUTO_READ_ONLY, "off");
- flags &= ~BDRV_O_COPY_ON_READ;
-
- /* snapshot=on is handled on the top layer */
- flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_TEMPORARY);
-
- *child_flags = flags;
+ bdrv_inherited_options(BDRV_CHILD_COW,
+ child_flags, child_options,
+ parent_flags, parent_options);
}
static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base,
@@ -3021,7 +3045,7 @@ static BlockDriverState *bdrv_open_inherit(const char
*filename,
flags, options);
/* Let bdrv_backing_options() override "read-only" */
qdict_del(options, BDRV_OPT_READ_ONLY);
- bdrv_backing_options(0, &flags, options, flags, options);
+ bdrv_inherited_options(BDRV_CHILD_COW, &flags, options, flags,
options);
}
bs->open_flags = flags;
--
2.23.0
