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block: Fix permissions after bdrv_reopen()

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If we switch between read-only and read-write, the permissions that
image format drivers need on bs->file change, too. Make sure to update
the permissions during bdrv_reopen().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Kevin Wolf 2017-07-03 17:07:35 +02:00
parent 1857c97b76
commit 3045025991
2 changed files with 65 additions and 0 deletions
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64
block.c
View file

@ -2781,6 +2781,10 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
bs_entry->state.explicit_options = explicit_options;
bs_entry->state.flags = flags;
/* This needs to be overwritten in bdrv_reopen_prepare() */
bs_entry->state.perm = UINT64_MAX;
bs_entry->state.shared_perm = 0;
QLIST_FOREACH(child, &bs->children, next) {
QDict *new_child_options;
char *child_key_dot;
@ -2887,6 +2891,52 @@ int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp)
return ret;
}
static BlockReopenQueueEntry *find_parent_in_reopen_queue(BlockReopenQueue *q,
BdrvChild *c)
{
BlockReopenQueueEntry *entry;
QSIMPLEQ_FOREACH(entry, q, entry) {
BlockDriverState *bs = entry->state.bs;
BdrvChild *child;
QLIST_FOREACH(child, &bs->children, next) {
if (child == c) {
return entry;
}
}
}
return NULL;
}
static void bdrv_reopen_perm(BlockReopenQueue *q, BlockDriverState *bs,
uint64_t *perm, uint64_t *shared)
{
BdrvChild *c;
BlockReopenQueueEntry *parent;
uint64_t cumulative_perms = 0;
uint64_t cumulative_shared_perms = BLK_PERM_ALL;
QLIST_FOREACH(c, &bs->parents, next_parent) {
parent = find_parent_in_reopen_queue(q, c);
if (!parent) {
cumulative_perms |= c->perm;
cumulative_shared_perms &= c->shared_perm;
} else {
uint64_t nperm, nshared;
bdrv_child_perm(parent->state.bs, bs, c, c->role, q,
parent->state.perm, parent->state.shared_perm,
&nperm, &nshared);
cumulative_perms |= nperm;
cumulative_shared_perms &= nshared;
}
}
*perm = cumulative_perms;
*shared = cumulative_shared_perms;
}
/*
* Prepares a BlockDriverState for reopen. All changes are staged in the
@ -2952,6 +3002,9 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
goto error;
}
/* Calculate required permissions after reopening */
bdrv_reopen_perm(queue, reopen_state->bs,
&reopen_state->perm, &reopen_state->shared_perm);
ret = bdrv_flush(reopen_state->bs);
if (ret) {
@ -3007,6 +3060,12 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
} while ((entry = qdict_next(reopen_state->options, entry)));
}
ret = bdrv_check_perm(reopen_state->bs, queue, reopen_state->perm,
reopen_state->shared_perm, NULL, errp);
if (ret < 0) {
goto error;
}
ret = 0;
error:
@ -3047,6 +3106,9 @@ void bdrv_reopen_commit(BDRVReopenState *reopen_state)
bdrv_refresh_limits(bs, NULL);
bdrv_set_perm(reopen_state->bs, reopen_state->perm,
reopen_state->shared_perm);
new_can_write =
!bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE);
if (!old_can_write && new_can_write && drv->bdrv_reopen_bitmaps_rw) {
@ -3080,6 +3142,8 @@ void bdrv_reopen_abort(BDRVReopenState *reopen_state)
}
QDECREF(reopen_state->explicit_options);
bdrv_abort_perm_update(reopen_state->bs);
}

1
include/block/block.h
View file

@ -166,6 +166,7 @@ typedef QSIMPLEQ_HEAD(BlockReopenQueue, BlockReopenQueueEntry) BlockReopenQueue;
typedef struct BDRVReopenState {
BlockDriverState *bs;
int flags;
uint64_t perm, shared_perm;
QDict *options;
QDict *explicit_options;
void *opaque;