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block: Pull out bdrv_default_perms_for_storage() 

Right now, bdrv_format_default_perms() is used by format parents
(generally). We want to switch to a model where most parents use a
single BdrvChildClass, which then decides the permissions based on the
child role. To do so, we have to split bdrv_format_default_perms() into
separate functions for each such role.

Note that bdrv_default_perms_for_storage() currently handles all DATA |
METADATA children.  A follow-up patch is going to split it further into
one function for each case.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200513110544.176672-18-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Max Reitz 2020-05-13 13:05:27 +02:00 committed by Kevin Wolf
parent 70082db4ef
commit 6f838a4b73
1 changed files with 46 additions and 25 deletions
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71
block.c
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@ -2506,6 +2506,50 @@ static void bdrv_default_perms_for_cow(BlockDriverState *bs, BdrvChild *c,
*nshared = shared;
}
static void bdrv_default_perms_for_storage(BlockDriverState *bs, BdrvChild *c,
const BdrvChildClass *child_class,
BdrvChildRole role,
BlockReopenQueue *reopen_queue,
uint64_t perm, uint64_t shared,
uint64_t *nperm, uint64_t *nshared)
{
int flags;
assert(child_class == &child_file ||
(child_class == &child_of_bds &&
(role & (BDRV_CHILD_METADATA | BDRV_CHILD_DATA))));
flags = bdrv_reopen_get_flags(reopen_queue, bs);
/*
* Apart from the modifications below, the same permissions are
* forwarded and left alone as for filters
*/
bdrv_filter_default_perms(bs, c, child_class, role, reopen_queue,
perm, shared, &perm, &shared);
/* Format drivers may touch metadata even if the guest doesn't write */
if (bdrv_is_writable_after_reopen(bs, reopen_queue)) {
perm |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
}
/*
* bs->file always needs to be consistent because of the metadata. We
* can never allow other users to resize or write to it.
*/
if (!(flags & BDRV_O_NO_IO)) {
perm |= BLK_PERM_CONSISTENT_READ;
}
shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
if (bs->open_flags & BDRV_O_INACTIVE) {
shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
}
*nperm = perm;
*nshared = shared;
}
void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
const BdrvChildClass *child_class,
BdrvChildRole role,
@ -2517,31 +2561,8 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
assert(child_class == &child_backing || child_class == &child_file);
if (!backing) {
int flags = bdrv_reopen_get_flags(reopen_queue, bs);
/* Apart from the modifications below, the same permissions are
* forwarded and left alone as for filters */
bdrv_filter_default_perms(bs, c, child_class, role, reopen_queue,
perm, shared, &perm, &shared);
/* Format drivers may touch metadata even if the guest doesn't write */
if (bdrv_is_writable_after_reopen(bs, reopen_queue)) {
perm |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
}
/* bs->file always needs to be consistent because of the metadata. We
* can never allow other users to resize or write to it. */
if (!(flags & BDRV_O_NO_IO)) {
perm |= BLK_PERM_CONSISTENT_READ;
}
shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
if (bs->open_flags & BDRV_O_INACTIVE) {
shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
}
*nperm = perm;
*nshared = shared;
bdrv_default_perms_for_storage(bs, c, child_class, role, reopen_queue,
perm, shared, nperm, nshared);
} else {
bdrv_default_perms_for_cow(bs, c, child_class, role, reopen_queue,
perm, shared, nperm, nshared);