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envelope-from=vsementsov@virtuozzo.com; helo=EUR05-AM6-obe.outbound.protection.outlook.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MSGID_FROM_MTA_HEADER=0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" To be used in the following commit. Signed-off-by: Vladimir Sementsov-Ogievskiy --- block.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) diff --git a/block.c b/block.c index d799afeedd..1b10b6fb5e 100644 --- a/block.c +++ b/block.c @@ -82,6 +82,9 @@ static BlockDriverState *bdrv_open_inherit(const char *filename, BdrvChildRole child_role, Error **errp); +static void bdrv_replace_child_noperm(BdrvChild *child, + BlockDriverState *new_bs); + /* If non-zero, use only whitelisted block drivers */ static int use_bdrv_whitelist; @@ -2142,6 +2145,57 @@ static int bdrv_drv_set_perm(BlockDriverState *bs, uint64_t perm, return 0; } +typedef struct BdrvReplaceChildState { + BdrvChild *child; + BlockDriverState *old_bs; +} BdrvReplaceChildState; + +static void bdrv_replace_child_commit(void *opaque) +{ + BdrvReplaceChildState *s = opaque; + + bdrv_unref(s->old_bs); +} + +static void bdrv_replace_child_abort(void *opaque) +{ + BdrvReplaceChildState *s = opaque; + BlockDriverState *new_bs = s->child->bs; + + /* old_bs reference is transparently moved from @s to @s->child */ + bdrv_replace_child_noperm(s->child, s->old_bs); + bdrv_unref(new_bs); +} + +static BdrvActionDrv bdrv_replace_child_drv = { + .commit = bdrv_replace_child_commit, + .abort = bdrv_replace_child_abort, + .clean = g_free, +}; + +/* + * bdrv_replace_child_safe + * + * Note: real unref of old_bs is done only on commit. + */ +__attribute__((unused)) +static void bdrv_replace_child_safe(BdrvChild *child, BlockDriverState *new_bs, + GSList **tran) +{ + BdrvReplaceChildState *s = g_new(BdrvReplaceChildState, 1); + *s = (BdrvReplaceChildState) { + .child = child, + .old_bs = child->bs, + }; + tran_prepend(tran, &bdrv_replace_child_drv, s); + + if (new_bs) { + bdrv_ref(new_bs); + } + bdrv_replace_child_noperm(child, new_bs); + /* old_bs reference is transparently moved from @child to @s */ +} + /* * Check whether permissions on this node can be changed in a way that * @cumulative_perms and @cumulative_shared_perms are the new cumulative -- 2.21.3