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[Qemu-devel] [PATCH 3/9] block: Remove child references from bs->{option
From: |
Alberto Garcia |
Subject: |
[Qemu-devel] [PATCH 3/9] block: Remove child references from bs->{options, explicit_options} |
Date: |
Sun, 26 Aug 2018 17:09:34 +0300 |
Block drivers allow opening their children using a reference to an
existing BlockDriverState. These references remain stored in the
'options' and 'explicit_options' QDicts, but we don't need to keep
them once everything is open.
What is more important, these values can become wrong if the children
change:
$ qemu-img create -f qcow2 hd0.qcow2 10M
$ qemu-img create -f qcow2 hd1.qcow2 10M
$ qemu-img create -f qcow2 hd2.qcow2 10M
$ $QEMU -drive if=none,file=hd0.qcow2,node-name=hd0 \
-drive if=none,file=hd1.qcow2,node-name=hd1,backing=hd0 \
-drive file=hd2.qcow2,node-name=hd2,backing=hd1
After this hd2 has hd1 as its backing file. Now let's remove it using
block_stream:
(qemu) block_stream hd2 0 hd0.qcow2
Now hd0 is the backing file of hd2, but hd2's options QDicts still
contain backing=hd1.
Signed-off-by: Alberto Garcia <address@hidden>
---
block.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/block.c b/block.c
index 0dbb1fcc7b..2f2484965d 100644
--- a/block.c
+++ b/block.c
@@ -2763,12 +2763,15 @@ static BlockDriverState *bdrv_open_inherit(const char
*filename,
}
}
- /* Remove all children options from bs->options and bs->explicit_options */
+ /* Remove all children options and references
+ * from bs->options and bs->explicit_options */
QLIST_FOREACH(child, &bs->children, next) {
char *child_key_dot;
child_key_dot = g_strdup_printf("%s.", child->name);
qdict_extract_subqdict(bs->explicit_options, NULL, child_key_dot);
qdict_extract_subqdict(bs->options, NULL, child_key_dot);
+ qdict_del(bs->explicit_options, child->name);
+ qdict_del(bs->options, child->name);
g_free(child_key_dot);
}
@@ -3289,6 +3292,7 @@ void bdrv_reopen_commit(BDRVReopenState *reopen_state)
{
BlockDriver *drv;
BlockDriverState *bs;
+ BdrvChild *child;
bool old_can_write, new_can_write;
assert(reopen_state != NULL);
@@ -3313,6 +3317,12 @@ void bdrv_reopen_commit(BDRVReopenState *reopen_state)
bs->open_flags = reopen_state->flags;
bs->read_only = !(reopen_state->flags & BDRV_O_RDWR);
+ /* Remove child references from bs->options and bs->explicit_options */
+ QLIST_FOREACH(child, &bs->children, next) {
+ qdict_del(bs->explicit_options, child->name);
+ qdict_del(bs->options, child->name);
+ }
+
bdrv_refresh_limits(bs, NULL);
bdrv_set_perm(reopen_state->bs, reopen_state->perm,
--
2.11.0
- [Qemu-devel] [PATCH 4/9] block: Don't look for child references in append_open_options(), (continued)
[Qemu-devel] [PATCH 8/9] block: Allow changing 'detect-zeroes' on reopen, Alberto Garcia, 2018/08/26
[Qemu-devel] [PATCH 3/9] block: Remove child references from bs->{options, explicit_options},
Alberto Garcia <=
[Qemu-devel] [PATCH 2/9] file-posix: x-check-cache-dropped should default to false on reopen, Alberto Garcia, 2018/08/26
[Qemu-devel] [PATCH 9/9] block: Allow changing 'force-share' on reopen, Alberto Garcia, 2018/08/26
[Qemu-devel] [PATCH 6/9] file-posix: Forbid trying to change unsupported options during reopen, Alberto Garcia, 2018/08/26