From 2f624b80ba67f19edb3f7c5bc27cddc3c844e443 Mon Sep 17 00:00:00 2001 From: Alberto Garcia Date: Fri, 29 Jun 2018 14:37:00 +0300 Subject: block: Remove children options from bs->{options,explicit_options} When bdrv_open_inherit() opens a BlockDriverState the options QDict can contain options for some of its children, passed in the form of child-name.option=value So while each child is opened with that subset of options, those same options remain stored in the parent BDS, leaving (at least) two copies of each one of them ("child-name.option=value" in the parent and "option=value" in the child). Having the children options stored in the parent is unnecessary and it can easily lead to an inconsistent state: $ qemu-img create -f qcow2 hd0.qcow2 10M $ qemu-img create -f qcow2 -b hd0.qcow2 hd1.qcow2 $ qemu-img create -f qcow2 -b hd1.qcow2 hd2.qcow2 $ $QEMU -drive file=hd2.qcow2,node-name=hd2,backing.node-name=hd1 This opens a chain of images hd0 <- hd1 <- hd2. Now let's remove hd1 using block_stream: (qemu) block_stream hd2 0 hd0.qcow2 After this hd2 contains backing.node-name=hd1, which is no longer correct because hd1 doesn't exist anymore. This patch removes all children options from the parent dictionaries at the end of bdrv_open_inherit() and bdrv_reopen_queue_child(). Signed-off-by: Alberto Garcia Signed-off-by: Kevin Wolf --- block.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'block.c') diff --git a/block.c b/block.c index 9694018a68..a8fbab396d 100644 --- a/block.c +++ b/block.c @@ -2584,6 +2584,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename, BlockBackend *file = NULL; BlockDriverState *bs; BlockDriver *drv = NULL; + BdrvChild *child; const char *drvname; const char *backing; Error *local_err = NULL; @@ -2767,6 +2768,15 @@ static BlockDriverState *bdrv_open_inherit(const char *filename, } } + /* Remove all children options 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); + g_free(child_key_dot); + } + bdrv_refresh_filename(bs); /* Check if any unknown options were used */ @@ -2976,6 +2986,7 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue, } child_key_dot = g_strdup_printf("%s.", child->name); + qdict_extract_subqdict(explicit_options, NULL, child_key_dot); qdict_extract_subqdict(options, &new_child_options, child_key_dot); g_free(child_key_dot); -- cgit v1.2.3