block.c (313274bbd4677f44631921ef4366f4ffc81cc5d5) block.c (d669ed6ab028497d634e1f236c74a98725f9e45f)
1/*
2 * QEMU System Emulator block driver
3 *
4 * Copyright (c) 2003 Fabrice Bellard
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights

--- 4896 unchanged lines hidden (view full) ---

4905 * if active == top, that is considered an error
4906 *
4907 */
4908int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
4909 const char *backing_file_str)
4910{
4911 BlockDriverState *explicit_top = top;
4912 bool update_inherits_from;
1/*
2 * QEMU System Emulator block driver
3 *
4 * Copyright (c) 2003 Fabrice Bellard
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights

--- 4896 unchanged lines hidden (view full) ---

4905 * if active == top, that is considered an error
4906 *
4907 */
4908int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
4909 const char *backing_file_str)
4910{
4911 BlockDriverState *explicit_top = top;
4912 bool update_inherits_from;
4913 BdrvChild *c, *next;
4913 BdrvChild *c;
4914 Error *local_err = NULL;
4915 int ret = -EIO;
4914 Error *local_err = NULL;
4915 int ret = -EIO;
4916 g_autoptr(GSList) updated_children = NULL;
4917 GSList *p;
4916
4917 bdrv_ref(top);
4918 bdrv_subtree_drained_begin(top);
4919
4920 if (!top->drv || !base->drv) {
4921 goto exit;
4922 }
4923
4924 /* Make sure that base is in the backing chain of top */
4925 if (!bdrv_chain_contains(top, base)) {
4926 goto exit;
4927 }
4928
4918
4919 bdrv_ref(top);
4920 bdrv_subtree_drained_begin(top);
4921
4922 if (!top->drv || !base->drv) {
4923 goto exit;
4924 }
4925
4926 /* Make sure that base is in the backing chain of top */
4927 if (!bdrv_chain_contains(top, base)) {
4928 goto exit;
4929 }
4930
4929 /* This function changes all links that point to top and makes
4930 * them point to base. Check that none of them is frozen. */
4931 QLIST_FOREACH(c, &top->parents, next_parent) {
4932 if (c->frozen) {
4933 goto exit;
4934 }
4935 }
4936
4937 /* If 'base' recursively inherits from 'top' then we should set
4938 * base->inherits_from to top->inherits_from after 'top' and all
4939 * other intermediate nodes have been dropped.
4940 * If 'top' is an implicit node (e.g. "commit_top") we should skip
4941 * it because no one inherits from it. We use explicit_top for that. */
4942 explicit_top = bdrv_skip_implicit_filters(explicit_top);
4943 update_inherits_from = bdrv_inherits_from_recursive(base, explicit_top);
4944
4945 /* success - we can delete the intermediate states, and link top->base */
4946 /* TODO Check graph modification op blockers (BLK_PERM_GRAPH_MOD) once
4947 * we've figured out how they should work. */
4948 if (!backing_file_str) {
4949 bdrv_refresh_filename(base);
4950 backing_file_str = base->filename;
4951 }
4952
4931 /* If 'base' recursively inherits from 'top' then we should set
4932 * base->inherits_from to top->inherits_from after 'top' and all
4933 * other intermediate nodes have been dropped.
4934 * If 'top' is an implicit node (e.g. "commit_top") we should skip
4935 * it because no one inherits from it. We use explicit_top for that. */
4936 explicit_top = bdrv_skip_implicit_filters(explicit_top);
4937 update_inherits_from = bdrv_inherits_from_recursive(base, explicit_top);
4938
4939 /* success - we can delete the intermediate states, and link top->base */
4940 /* TODO Check graph modification op blockers (BLK_PERM_GRAPH_MOD) once
4941 * we've figured out how they should work. */
4942 if (!backing_file_str) {
4943 bdrv_refresh_filename(base);
4944 backing_file_str = base->filename;
4945 }
4946
4953 QLIST_FOREACH_SAFE(c, &top->parents, next_parent, next) {
4954 /* Check whether we are allowed to switch c from top to base */
4955 GSList *ignore_children = g_slist_prepend(NULL, c);
4956 ret = bdrv_check_update_perm(base, NULL, c->perm, c->shared_perm,
4957 ignore_children, NULL, &local_err);
4958 g_slist_free(ignore_children);
4959 if (ret < 0) {
4960 error_report_err(local_err);
4961 goto exit;
4962 }
4947 QLIST_FOREACH(c, &top->parents, next_parent) {
4948 updated_children = g_slist_prepend(updated_children, c);
4949 }
4963
4950
4964 /* If so, update the backing file path in the image file */
4951 bdrv_replace_node_common(top, base, false, &local_err);
4952 if (local_err) {
4953 error_report_err(local_err);
4954 goto exit;
4955 }
4956
4957 for (p = updated_children; p; p = p->next) {
4958 c = p->data;
4959
4965 if (c->klass->update_filename) {
4966 ret = c->klass->update_filename(c, base, backing_file_str,
4967 &local_err);
4968 if (ret < 0) {
4960 if (c->klass->update_filename) {
4961 ret = c->klass->update_filename(c, base, backing_file_str,
4962 &local_err);
4963 if (ret < 0) {
4969 bdrv_abort_perm_update(base);
4964 /*
4965 * TODO: Actually, we want to rollback all previous iterations
4966 * of this loop, and (which is almost impossible) previous
4967 * bdrv_replace_node()...
4968 *
4969 * Note, that c->klass->update_filename may lead to permission
4970 * update, so it's a bad idea to call it inside permission
4971 * update transaction of bdrv_replace_node.
4972 */
4970 error_report_err(local_err);
4971 goto exit;
4972 }
4973 }
4973 error_report_err(local_err);
4974 goto exit;
4975 }
4976 }
4974
4975 /*
4976 * Do the actual switch in the in-memory graph.
4977 * Completes bdrv_check_update_perm() transaction internally.
4978 * c->frozen is false, we have checked that above.
4979 */
4980 bdrv_ref(base);
4981 bdrv_replace_child(c, base);
4982 bdrv_unref(top);
4983 }
4984
4985 if (update_inherits_from) {
4986 base->inherits_from = explicit_top->inherits_from;
4987 }
4988
4989 ret = 0;
4990exit:

--- 2260 unchanged lines hidden --- 		4977 }
4978
4979 if (update_inherits_from) {
4980 base->inherits_from = explicit_top->inherits_from;
4981 }
4982
4983 ret = 0;
4984exit:

--- 2260 unchanged lines hidden ---