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block: refactor bdrv_child* permission functions

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Split out non-recursive parts, and refactor as block graph transaction
action.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210428151804.439460-11-vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2021-04-28 18:17:38 +03:00 committed by Kevin Wolf
parent 3bf416ba0f
commit b0defa8356
1 changed files with 59 additions and 20 deletions
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79
block.c
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@ -49,6 +49,7 @@
#include "qemu/timer.h"
#include "qemu/cutils.h"
#include "qemu/id.h"
#include "qemu/transactions.h"
#include "block/coroutines.h"
#ifdef CONFIG_BSD
@ -2093,6 +2094,61 @@ static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs,
}
}
static void bdrv_child_set_perm_commit(void *opaque)
{
BdrvChild *c = opaque;
c->has_backup_perm = false;
}
static void bdrv_child_set_perm_abort(void *opaque)
{
BdrvChild *c = opaque;
/*
* We may have child->has_backup_perm unset at this point, as in case of
* _check_ stage of permission update failure we may _check_ not the whole
* subtree. Still, _abort_ is called on the whole subtree anyway.
*/
if (c->has_backup_perm) {
c->perm = c->backup_perm;
c->shared_perm = c->backup_shared_perm;
c->has_backup_perm = false;
}
}
static TransactionActionDrv bdrv_child_set_pem_drv = {
.abort = bdrv_child_set_perm_abort,
.commit = bdrv_child_set_perm_commit,
};
/*
* With tran=NULL needs to be followed by direct call to either
* bdrv_child_set_perm_commit() or bdrv_child_set_perm_abort().
*
* With non-NULL tran needs to be followed by tran_abort() or tran_commit()
* instead.
*/
static void bdrv_child_set_perm_safe(BdrvChild *c, uint64_t perm,
uint64_t shared, Transaction *tran)
{
if (!c->has_backup_perm) {
c->has_backup_perm = true;
c->backup_perm = c->perm;
c->backup_shared_perm = c->shared_perm;
}
/*
* Note: it's OK if c->has_backup_perm was already set, as we can find the
* same c twice during check_perm procedure
*/
c->perm = perm;
c->shared_perm = shared;
if (tran) {
tran_add(tran, &bdrv_child_set_pem_drv, c);
}
}
/*
* Check whether permissions on this node can be changed in a way that
* @cumulative_perms and @cumulative_shared_perms are the new cumulative
@ -2358,37 +2414,20 @@ static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q,
return ret;
}
if (!c->has_backup_perm) {
c->has_backup_perm = true;
c->backup_perm = c->perm;
c->backup_shared_perm = c->shared_perm;
}
/*
* Note: it's OK if c->has_backup_perm was already set, as we can find the
* same child twice during check_perm procedure
*/
c->perm = perm;
c->shared_perm = shared;
bdrv_child_set_perm_safe(c, perm, shared, NULL);
return 0;
}
static void bdrv_child_set_perm(BdrvChild *c)
{
c->has_backup_perm = false;
bdrv_child_set_perm_commit(c);
bdrv_set_perm(c->bs);
}
static void bdrv_child_abort_perm_update(BdrvChild *c)
{
if (c->has_backup_perm) {
c->perm = c->backup_perm;
c->shared_perm = c->backup_shared_perm;
c->has_backup_perm = false;
}
bdrv_child_set_perm_abort(c);
bdrv_abort_perm_update(c->bs);
}