Use child access functions when iterating through backing chains so
filters do not break the chain.
In addition, bdrv_find_overlay() will now always return the actual
overlay; that is, it will never return a filter node but only one with a
COW backing file (there may be filter nodes between that node and @bs).
Signed-off-by: Max Reitz
---
block.c | 41 +
1 file changed, 29 insertions(+), 12 deletions(-)
diff --git a/block.c b/block.c
index a44af9c3c1..712230ef5c 100644
--- a/block.c
+++ b/block.c
@@ -4724,7 +4724,8 @@ int bdrv_change_backing_file(BlockDriverState *bs,
}
/*
- * Finds the image layer in the chain that has 'bs' as its backing file.
+ * Finds the image layer in the chain that has 'bs' (or a filter on
+ * top of it) as its backing file.
*
* active is the current topmost image.
*
@@ -4736,11 +4737,18 @@ int bdrv_change_backing_file(BlockDriverState *bs,
BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
BlockDriverState *bs)
{
-while (active && bs != backing_bs(active)) {
-active = backing_bs(active);
+bs = bdrv_skip_filters(bs);
+active = bdrv_skip_filters(active);
+
+while (active) {
+BlockDriverState *next = bdrv_backing_chain_next(active);
+if (bs == next) {
+return active;
+}
+active = next;
}
-return active;
+return NULL;
}
/* Given a BDS, searches for the base layer. */
@@ -4892,9 +4900,7 @@ int bdrv_drop_intermediate(BlockDriverState *top,
BlockDriverState *base,
* other intermediate nodes have been dropped.
* If 'top' is an implicit node (e.g. "commit_top") we should skip
* it because no one inherits from it. We use explicit_top for that. */
-while (explicit_top && explicit_top->implicit) {
-explicit_top = backing_bs(explicit_top);
-}
+explicit_top = bdrv_skip_implicit_filters(explicit_top);
update_inherits_from = bdrv_inherits_from_recursive(base, explicit_top);
/* success - we can delete the intermediate states, and link top->base */
@@ -5351,7 +5357,7 @@ BlockDriverState *bdrv_lookup_bs(const char *device,
bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base)
{
while (top && top != base) {
-top = backing_bs(top);
+top = bdrv_filter_or_cow_bs(top);
}
return top != NULL;
@@ -5607,6 +5613,7 @@ BlockDriverState
*bdrv_find_backing_image(BlockDriverState *bs,
int is_protocol = 0;
BlockDriverState *curr_bs = NULL;
BlockDriverState *retval = NULL;
+BlockDriverState *bs_below;
if (!bs || !bs->drv || !backing_file) {
return NULL;
@@ -5617,7 +5624,17 @@ BlockDriverState
*bdrv_find_backing_image(BlockDriverState *bs,
is_protocol = path_has_protocol(backing_file);
-for (curr_bs = bs; curr_bs->backing; curr_bs = curr_bs->backing->bs) {
+/*
+ * Being largely a legacy function, skip any filters here
+ * (because filters do not have normal filenames, so they cannot
+ * match anyway; and allowing json:{} filenames is a bit out of
+ * scope).
+ */
+for (curr_bs = bdrv_skip_filters(bs);
+ bdrv_cow_child(curr_bs) != NULL;
+ curr_bs = bs_below)
+{
+bs_below = bdrv_backing_chain_next(curr_bs);
/* If either of the filename paths is actually a protocol, then
* compare unmodified paths; otherwise make paths relative */
@@ -5625,7 +5642,7 @@ BlockDriverState
*bdrv_find_backing_image(BlockDriverState *bs,
char *backing_file_full_ret;
if (strcmp(backing_file, curr_bs->backing_file) == 0) {
-retval = curr_bs->backing->bs;
+retval = bs_below;
break;
}
/* Also check against the full backing filename for the image */
@@ -5635,7 +5652,7 @@ BlockDriverState
*bdrv_find_backing_image(BlockDriverState *bs,
bool equal = strcmp(backing_file, backing_file_full_ret) == 0;
g_free(backing_file_full_ret);
if (equal) {
-retval = curr_bs->backing->bs;
+retval = bs_below;
break;
}
}
@@ -5661,7 +5678,7 @@ BlockDriverState
*bdrv_find_backing_image(BlockDriverState *bs,
g_free(filename_tmp);
if (strcmp(backing_file_full, filename_full) == 0) {
-retval = curr_bs->backing->bs;
+retval = bs_below;
break;
}
}
--
2.26.2
