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block: Fix permissions in image activation

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Inactive images generally request less permissions for their image files
than they would if they were active (in particular, write permissions).
Activating the image involves extending the permissions, therefore.

drv->bdrv_invalidate_cache() can already require write access to the
image file, so we have to update the permissions earlier than that.
The current code does it only later, so we have to move up this part.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Kevin Wolf 2017-11-16 13:00:01 +01:00
parent f06033295b
commit dafe096057
1 changed files with 22 additions and 10 deletions
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32
block.c
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@ -4174,7 +4174,29 @@ void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp)
}
}
/*
* Update permissions, they may differ for inactive nodes.
*
* Note that the required permissions of inactive images are always a
* subset of the permissions required after activating the image. This
* allows us to just get the permissions upfront without restricting
* drv->bdrv_invalidate_cache().
*
* It also means that in error cases, we don't have to try and revert to
* the old permissions (which is an operation that could fail, too). We can
* just keep the extended permissions for the next time that an activation
* of the image is tried.
*/
bs->open_flags &= ~BDRV_O_INACTIVE;
bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, &local_err);
if (ret < 0) {
bs->open_flags |= BDRV_O_INACTIVE;
error_propagate(errp, local_err);
return;
}
bdrv_set_perm(bs, perm, shared_perm);
if (bs->drv->bdrv_invalidate_cache) {
bs->drv->bdrv_invalidate_cache(bs, &local_err);
if (local_err) {
@ -4191,16 +4213,6 @@ void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp)
return;
}
/* Update permissions, they may differ for inactive nodes */
bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, &local_err);
if (ret < 0) {
bs->open_flags |= BDRV_O_INACTIVE;
error_propagate(errp, local_err);
return;
}
bdrv_set_perm(bs, perm, shared_perm);
QLIST_FOREACH(parent, &bs->parents, next_parent) {
if (parent->role->activate) {
parent->role->activate(parent, &local_err);