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block: Make backing files child_of_bds children 

Make all parents of backing files pass the appropriate BdrvChildRole.
By doing so, we can switch their BdrvChildClass over to the generic
child_of_bds, which will do the right thing when given a correct
BdrvChildRole.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200513110544.176672-24-mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Max Reitz 2020-05-13 13:05:33 +02:00 committed by Kevin Wolf
parent f34ade1148
commit 25191e5ff0
4 changed files with 30 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
block.c
View File

@ -2941,6 +2941,20 @@ static bool bdrv_inherits_from_recursive(BlockDriverState *child,
return child != NULL;
}
/*
* Return the BdrvChildRole for @bs's backing child. bs->backing is
* mostly used for COW backing children (role = COW), but also for
* filtered children (role = FILTERED | PRIMARY).
*/
static BdrvChildRole bdrv_backing_role(BlockDriverState *bs)
{
if (bs->drv && bs->drv->is_filter) {
return BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY;
} else {
return BDRV_CHILD_COW;
}
}
/*
* Sets the backing file link of a BDS. A new reference is created; callers
* which don't need their own reference any more must call bdrv_unref().
@ -2968,8 +2982,8 @@ void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
goto out;
}
bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_backing,
0, errp);
bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_of_bds,
bdrv_backing_role(bs), errp);
/* If backing_hd was already part of bs's backing chain, and
* inherits_from pointed recursively to bs then let's update it to
* point directly to bs (else it will become NULL). */
@ -3066,7 +3080,7 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
}
backing_hd = bdrv_open_inherit(backing_filename, reference, options, 0, bs,
&child_backing, 0, errp);
&child_of_bds, bdrv_backing_role(bs), errp);
if (!backing_hd) {
bs->open_flags |= BDRV_O_NO_BACKING;
error_prepend(errp, "Could not open backing file: ");
@ -3895,8 +3909,8 @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
if (state->replace_backing_bs && state->new_backing_bs) {
uint64_t nperm, nshared;
bdrv_child_perm(state->bs, state->new_backing_bs,
NULL, &child_backing, 0, bs_queue,
state->perm, state->shared_perm,
NULL, &child_of_bds, bdrv_backing_role(state->bs),
bs_queue, state->perm, state->shared_perm,
&nperm, &nshared);
ret = bdrv_check_update_perm(state->new_backing_bs, NULL,
nperm, nshared, NULL, NULL, errp);
@ -6852,7 +6866,7 @@ void bdrv_refresh_filename(BlockDriverState *bs)
drv->bdrv_gather_child_options(bs, opts, backing_overridden);
} else {
QLIST_FOREACH(child, &bs->children, next) {
if (child->klass == &child_backing && !backing_overridden) {
if (child == bs->backing && !backing_overridden) {
/* We can skip the backing BDS if it has not been overridden */
continue;
}

2
block/backup-top.c
View File

@ -143,7 +143,7 @@ static void backup_top_child_perm(BlockDriverState *bs, BdrvChild *c,
return;
}
if (child_class == &child_file) {
if (!(role & BDRV_CHILD_FILTERED)) {
/*
* Target child
*

3
block/vvfat.c
View File

@ -3219,7 +3219,8 @@ static void vvfat_child_perm(BlockDriverState *bs, BdrvChild *c,
{
BDRVVVFATState *s = bs->opaque;
assert(c == s->qcow || child_class == &child_backing);
assert(c == s->qcow ||
(child_class == &child_of_bds && (role & BDRV_CHILD_COW)));
if (c == s->qcow) {
/* This is a private node, nobody should try to attach to it */

13
tests/test-bdrv-drain.c
View File

@ -96,7 +96,7 @@ static void bdrv_test_child_perm(BlockDriverState *bs, BdrvChild *c,
* bdrv_format_default_perms() accepts only these two, so disguise
* detach_by_driver_cb_parent as one of them.
*/
if (child_class != &child_file && child_class != &child_backing) {
if (child_class != &child_file && child_class != &child_of_bds) {
child_class = &child_file;
}
@ -1399,8 +1399,8 @@ static void test_detach_indirect(bool by_parent_cb)
bdrv_ref(a);
child_b = bdrv_attach_child(parent_b, b, "PB-B", &child_file, 0,
&error_abort);
child_a = bdrv_attach_child(parent_b, a, "PB-A", &child_backing, 0,
&error_abort);
child_a = bdrv_attach_child(parent_b, a, "PB-A", &child_of_bds,
BDRV_CHILD_COW, &error_abort);
bdrv_ref(a);
bdrv_attach_child(parent_a, a, "PA-A",
@ -1793,7 +1793,7 @@ static void test_drop_intermediate_poll(void)
int i;
int ret;
chain_child_class = child_backing;
chain_child_class = child_of_bds;
chain_child_class.update_filename = drop_intermediate_poll_update_filename;
for (i = 0; i < 3; i++) {
@ -1816,7 +1816,7 @@ static void test_drop_intermediate_poll(void)
/* Takes the reference to chain[i - 1] */
chain[i]->backing = bdrv_attach_child(chain[i], chain[i - 1],
"chain", &chain_child_class,
0, &error_abort);
BDRV_CHILD_COW, &error_abort);
}
}
@ -2034,7 +2034,8 @@ static void do_test_replace_child_mid_drain(int old_drain_count,
bdrv_ref(old_child_bs);
parent_bs->backing = bdrv_attach_child(parent_bs, old_child_bs, "child",
&child_backing, 0, &error_abort);
&child_of_bds, BDRV_CHILD_COW,
&error_abort);
for (i = 0; i < old_drain_count; i++) {
bdrv_drained_begin(old_child_bs);