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block: add bdrv_attach_child_common() transaction action

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Split out no-perm part of bdrv_root_attach_child() into separate
transaction action. bdrv_root_attach_child() now moves to new
permission update paradigm: first update graph relations then update
permissions.

qsd-jobs test output updated. Seems now permission update goes in
another order. Still, the test comment say that we only want to check
that command doesn't crash, and it's still so.

Error message is a bit misleading as it looks like job was added first.
But actually in new paradigm of graph update we can't distinguish such
things. We should update the error message, but let's not do it now.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210428151804.439460-19-vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2021-04-28 18:17:46 +03:00 committed by Kevin Wolf
parent 3bb0e2980a
commit 548a74c0db
2 changed files with 139 additions and 57 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

194
block.c
View File

@ -2955,6 +2955,136 @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
}
}
static void bdrv_remove_empty_child(BdrvChild *child)
{
assert(!child->bs);
QLIST_SAFE_REMOVE(child, next);
g_free(child->name);
g_free(child);
}
typedef struct BdrvAttachChildCommonState {
BdrvChild **child;
AioContext *old_parent_ctx;
AioContext *old_child_ctx;
} BdrvAttachChildCommonState;
static void bdrv_attach_child_common_abort(void *opaque)
{
BdrvAttachChildCommonState *s = opaque;
BdrvChild *child = *s->child;
BlockDriverState *bs = child->bs;
bdrv_replace_child_noperm(child, NULL);
if (bdrv_get_aio_context(bs) != s->old_child_ctx) {
bdrv_try_set_aio_context(bs, s->old_child_ctx, &error_abort);
}
if (bdrv_child_get_parent_aio_context(child) != s->old_parent_ctx) {
GSList *ignore = g_slist_prepend(NULL, child);
child->klass->can_set_aio_ctx(child, s->old_parent_ctx, &ignore,
&error_abort);
g_slist_free(ignore);
ignore = g_slist_prepend(NULL, child);
child->klass->set_aio_ctx(child, s->old_parent_ctx, &ignore);
g_slist_free(ignore);
}
bdrv_unref(bs);
bdrv_remove_empty_child(child);
*s->child = NULL;
}
static TransactionActionDrv bdrv_attach_child_common_drv = {
.abort = bdrv_attach_child_common_abort,
.clean = g_free,
};
/*
* Common part of attaching bdrv child to bs or to blk or to job
*/
static int bdrv_attach_child_common(BlockDriverState *child_bs,
const char *child_name,
const BdrvChildClass *child_class,
BdrvChildRole child_role,
uint64_t perm, uint64_t shared_perm,
void *opaque, BdrvChild **child,
Transaction *tran, Error **errp)
{
BdrvChild *new_child;
AioContext *parent_ctx;
AioContext *child_ctx = bdrv_get_aio_context(child_bs);
assert(child);
assert(*child == NULL);
new_child = g_new(BdrvChild, 1);
*new_child = (BdrvChild) {
.bs = NULL,
.name = g_strdup(child_name),
.klass = child_class,
.role = child_role,
.perm = perm,
.shared_perm = shared_perm,
.opaque = opaque,
};
/*
* If the AioContexts don't match, first try to move the subtree of
* child_bs into the AioContext of the new parent. If this doesn't work,
* try moving the parent into the AioContext of child_bs instead.
*/
parent_ctx = bdrv_child_get_parent_aio_context(new_child);
if (child_ctx != parent_ctx) {
Error *local_err = NULL;
int ret = bdrv_try_set_aio_context(child_bs, parent_ctx, &local_err);
if (ret < 0 && child_class->can_set_aio_ctx) {
GSList *ignore = g_slist_prepend(NULL, new_child);
if (child_class->can_set_aio_ctx(new_child, child_ctx, &ignore,
NULL))
{
error_free(local_err);
ret = 0;
g_slist_free(ignore);
ignore = g_slist_prepend(NULL, new_child);
child_class->set_aio_ctx(new_child, child_ctx, &ignore);
}
g_slist_free(ignore);
}
if (ret < 0) {
error_propagate(errp, local_err);
bdrv_remove_empty_child(new_child);
return ret;
}
}
bdrv_ref(child_bs);
bdrv_replace_child_noperm(new_child, child_bs);
*child = new_child;
BdrvAttachChildCommonState *s = g_new(BdrvAttachChildCommonState, 1);
*s = (BdrvAttachChildCommonState) {
.child = child,
.old_parent_ctx = parent_ctx,
.old_child_ctx = child_ctx,
};
tran_add(tran, &bdrv_attach_child_common_drv, s);
return 0;
}
static void bdrv_detach_child(BdrvChild *child)
{
bdrv_replace_child(child, NULL);
bdrv_remove_empty_child(child);
}
/*
* This function steals the reference to child_bs from the caller.
* That reference is later dropped by bdrv_root_unref_child().
@ -2972,60 +3102,22 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
uint64_t perm, uint64_t shared_perm,
void *opaque, Error **errp)
{
BdrvChild *child;
Error *local_err = NULL;
int ret;
AioContext *ctx;
BdrvChild *child = NULL;
Transaction *tran = tran_new();
ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, errp);
ret = bdrv_attach_child_common(child_bs, child_name, child_class,
child_role, perm, shared_perm, opaque,
&child, tran, errp);
if (ret < 0) {
bdrv_abort_perm_update(child_bs);
bdrv_unref(child_bs);
return NULL;
}
child = g_new(BdrvChild, 1);
*child = (BdrvChild) {
.bs = NULL,
.name = g_strdup(child_name),
.klass = child_class,
.role = child_role,
.perm = perm,
.shared_perm = shared_perm,
.opaque = opaque,
};
ctx = bdrv_child_get_parent_aio_context(child);
/* If the AioContexts don't match, first try to move the subtree of
* child_bs into the AioContext of the new parent. If this doesn't work,
* try moving the parent into the AioContext of child_bs instead. */
if (bdrv_get_aio_context(child_bs) != ctx) {
ret = bdrv_try_set_aio_context(child_bs, ctx, &local_err);
if (ret < 0 && child_class->can_set_aio_ctx) {
GSList *ignore = g_slist_prepend(NULL, child);
ctx = bdrv_get_aio_context(child_bs);
if (child_class->can_set_aio_ctx(child, ctx, &ignore, NULL)) {
error_free(local_err);
ret = 0;
g_slist_free(ignore);
ignore = g_slist_prepend(NULL, child);
child_class->set_aio_ctx(child, ctx, &ignore);
}
g_slist_free(ignore);
}
if (ret < 0) {
error_propagate(errp, local_err);
g_free(child);
bdrv_abort_perm_update(child_bs);
bdrv_unref(child_bs);
return NULL;
}
}
/* This performs the matching bdrv_set_perm() for the above check. */
bdrv_replace_child(child, child_bs);
ret = bdrv_refresh_perms(child_bs, errp);
tran_finalize(tran, ret);
bdrv_unref(child_bs);
return child;
}
@ -3067,16 +3159,6 @@ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
return child;
}
static void bdrv_detach_child(BdrvChild *child)
{
QLIST_SAFE_REMOVE(child, next);
bdrv_replace_child(child, NULL);
g_free(child->name);
g_free(child);
}
/* Callers must ensure that child->frozen is false. */
void bdrv_root_unref_child(BdrvChild *child)
{

2
tests/qemu-iotests/tests/qsd-jobs.out
View File

@ -16,7 +16,7 @@ QMP_VERSION
{"return": {}}
{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "created", "id": "job0"}}
{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "null", "id": "job0"}}
{"error": {"class": "GenericError", "desc": "Conflicts with use by a block device as 'root', which uses 'write' on fmt_base"}}
{"error": {"class": "GenericError", "desc": "Conflicts with use by stream job 'job0' as 'intermediate node', which does not allow 'write' on fmt_base"}}
{"return": {}}
{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_EXPORT_DELETED", "data": {"id": "export1"}}
*** done