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author | Max Reitz <mreitz@redhat.com> | 2019-05-22 19:03:46 +0200 |
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committer | Kevin Wolf <kwolf@redhat.com> | 2019-06-18 16:41:10 +0200 |
commit | c1087f12066a1ff34153dd10662c1a46a874087c (patch) | |
tree | 11bcae3d454cd19afb63da0c8047e9326e4456ff /block.c | |
parent | 094e36394481fd2c8493cec2a7c026f342232f15 (diff) | |
download | qemu-c1087f12066a1ff34153dd10662c1a46a874087c.zip qemu-c1087f12066a1ff34153dd10662c1a46a874087c.tar.gz qemu-c1087f12066a1ff34153dd10662c1a46a874087c.tar.bz2 |
block: Add bdrv_child_refresh_perms()
If a block node uses bdrv_child_try_set_perm() to change the permission
it takes on its child, the result may be very short-lived. If anything
makes the block layer recalculate the permissions internally, it will
invoke the node driver's .bdrv_child_perm() implementation. The
permission/shared permissions masks that returns will then override the
values previously passed to bdrv_child_try_set_perm().
If drivers want a child edge to have specific values for the
permissions/shared permissions mask, it must return them in
.bdrv_child_perm(). Consequentially, there is no need for them to pass
the same values to bdrv_child_try_set_perm() then: It is better to have
a function that invokes .bdrv_child_perm() and calls
bdrv_child_try_set_perm() with the result. This patch adds such a
function under the name of bdrv_child_refresh_perms().
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block.c')
-rw-r--r-- | block.c | 12 |
1 files changed, 12 insertions, 0 deletions
@@ -2083,6 +2083,18 @@ int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, return 0; } +int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp) +{ + uint64_t parent_perms, parent_shared; + uint64_t perms, shared; + + bdrv_get_cumulative_perm(bs, &parent_perms, &parent_shared); + bdrv_child_perm(bs, c->bs, c, c->role, NULL, parent_perms, parent_shared, + &perms, &shared); + + return bdrv_child_try_set_perm(c, perms, shared, errp); +} + void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c, const BdrvChildRole *role, BlockReopenQueue *reopen_queue, |