include/migration/blocker.h

   1 /*
   2  * QEMU migration blockers
   3  *
   4  * Copyright IBM, Corp. 2008
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  */
  13
  14 #ifndef MIGRATION_BLOCKER_H
  15 #define MIGRATION_BLOCKER_H
  16
  17 #include "qapi/qapi-types-migration.h"
  18
  19 #define MIG_MODE_ALL MIG_MODE__MAX
  20
  21 /**
  22  * @migrate_add_blocker - prevent all modes of migration from proceeding
  23  *
  24  * @reasonp - address of an error to be returned whenever migration is attempted
  25  *
  26  * @errp - [out] The reason (if any) we cannot block migration right now.
  27  *
  28  * @returns - 0 on success, -EBUSY/-EACCES on failure, with errp set.
  29  *
  30  * *@reasonp is freed and set to NULL if failure is returned.
  31  * On success, the caller must not free @reasonp, except by
  32  *   calling migrate_del_blocker.
  33  */
  34 int migrate_add_blocker(Error **reasonp, Error **errp);
  35
  36 /**
  37  * @migrate_add_blocker_internal - prevent all modes of migration from
  38  *                                 proceeding, but ignore -only-migratable
  39  *
  40  * @reasonp - address of an error to be returned whenever migration is attempted
  41  *
  42  * @errp - [out] The reason (if any) we cannot block migration right now.
  43  *
  44  * @returns - 0 on success, -EBUSY on failure, with errp set.
  45  *
  46  * Some of the migration blockers can be temporary (e.g., for a few seconds),
  47  * so it shouldn't need to conflict with "-only-migratable".  For those cases,
  48  * we can call this function rather than @migrate_add_blocker().
  49  *
  50  * *@reasonp is freed and set to NULL if failure is returned.
  51  * On success, the caller must not free @reasonp, except by
  52  *   calling migrate_del_blocker.
  53  */
  54 int migrate_add_blocker_internal(Error **reasonp, Error **errp);
  55
  56 /**
  57  * @migrate_del_blocker - remove a migration blocker from all modes and free it.
  58  *
  59  * @reasonp - address of the error blocking migration
  60  *
  61  * This function frees *@reasonp and sets it to NULL.
  62  */
  63 void migrate_del_blocker(Error **reasonp);
  64
  65 /**
  66  * @migrate_add_blocker_normal - prevent normal migration mode from proceeding
  67  *
  68  * @reasonp - address of an error to be returned whenever migration is attempted
  69  *
  70  * @errp - [out] The reason (if any) we cannot block migration right now.
  71  *
  72  * @returns - 0 on success, -EBUSY/-EACCES on failure, with errp set.
  73  *
  74  * *@reasonp is freed and set to NULL if failure is returned.
  75  * On success, the caller must not free @reasonp, except by
  76  *   calling migrate_del_blocker.
  77  */
  78 int migrate_add_blocker_normal(Error **reasonp, Error **errp);
  79
  80 /**
  81  * @migrate_add_blocker_modes - prevent some modes of migration from proceeding
  82  *
  83  * @reasonp - address of an error to be returned whenever migration is attempted
  84  *
  85  * @errp - [out] The reason (if any) we cannot block migration right now.
  86  *
  87  * @mode - one or more migration modes to be blocked.  The list is terminated
  88  *         by -1 or MIG_MODE_ALL.  For the latter, all modes are blocked.
  89  *
  90  * @returns - 0 on success, -EBUSY/-EACCES on failure, with errp set.
  91  *
  92  * *@reasonp is freed and set to NULL if failure is returned.
  93  * On success, the caller must not free *@reasonp before the blocker is removed.
  94  */
  95 int migrate_add_blocker_modes(Error **reasonp, Error **errp, MigMode mode, ...);
  96
  97 #endif