diff options
| -rw-r--r-- | block.c | 62 |
1 files changed, 40 insertions, 22 deletions
@@ -2468,6 +2468,44 @@ void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c, *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED; } +static void bdrv_default_perms_for_cow(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) +{ + assert(child_class == &child_backing || + (child_class == &child_of_bds && (role & BDRV_CHILD_COW))); + + /* + * We want consistent read from backing files if the parent needs it. + * No other operations are performed on backing files. + */ + perm &= BLK_PERM_CONSISTENT_READ; + + /* + * If the parent can deal with changing data, we're okay with a + * writable and resizable backing file. + * TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too? + */ + if (shared & BLK_PERM_WRITE) { + shared = BLK_PERM_WRITE | BLK_PERM_RESIZE; + } else { + shared = 0; + } + + shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD | + BLK_PERM_WRITE_UNCHANGED; + + 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, @@ -2505,28 +2543,8 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c, *nperm = perm; *nshared = shared; } else { - /* We want consistent read from backing files if the parent needs it. - * No other operations are performed on backing files. */ - perm &= BLK_PERM_CONSISTENT_READ; - - /* If the parent can deal with changing data, we're okay with a - * writable and resizable backing file. */ - /* TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too? */ - if (shared & BLK_PERM_WRITE) { - shared = BLK_PERM_WRITE | BLK_PERM_RESIZE; - } else { - shared = 0; - } - - shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD | - BLK_PERM_WRITE_UNCHANGED; - - if (bs->open_flags & BDRV_O_INACTIVE) { - shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE; - } - - *nperm = perm; - *nshared = shared; + bdrv_default_perms_for_cow(bs, c, child_class, role, reopen_queue, + perm, shared, nperm, nshared); } } |