Split out no-perm part of bdrv_root_attach_child() into separate
transaction action. bdrv_root_attach_child() now moves to new
permission update paradigm: first update graph relations then update
permissions.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
block.c | 189 ++++++++++++++++++++++++++++++++++++++++----------------
1 file changed, 135 insertions(+), 54 deletions(-)
diff --git a/block.c b/block.c
index 98ff44dbf7..b6bdc534d2 100644
--- a/block.c
+++ b/block.c
@@ -2921,37 +2921,73 @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
}
}
-/*
- * This function steals the reference to child_bs from the caller.
- * That reference is later dropped by bdrv_root_unref_child().
- *
- * On failure NULL is returned, errp is set and the reference to
- * child_bs is also dropped.
- *
- * The caller must hold the AioContext lock @child_bs, but not that of @ctx
- * (unless @child_bs is already in @ctx).
- */
-BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
- const char *child_name,
- const BdrvChildClass *child_class,
- BdrvChildRole child_role,
- uint64_t perm, uint64_t shared_perm,
- void *opaque, Error **errp)
+static void bdrv_remove_empty_child(BdrvChild *child)
{
- BdrvChild *child;
- Error *local_err = NULL;
- int ret;
- AioContext *ctx;
+ assert(!child->bs);
+ QLIST_SAFE_REMOVE(child, next);
+ g_free(child->name);
+ g_free(child);
+}
- ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, errp);
- if (ret < 0) {
- bdrv_abort_perm_update(child_bs);
- bdrv_unref(child_bs);
- return NULL;
+typedef struct BdrvAttachChildCommonState {
+ BdrvChild **child;
+ AioContext *old_parent_ctx;
+ AioContext *old_child_ctx;
+} BdrvAttachChildCommonState;
+
+static void bdrv_attach_child_common_abort(void *opaque)
+{
+ BdrvAttachChildCommonState *s = opaque;
+ BdrvChild *child = *s->child;
+ BlockDriverState *bs = child->bs;
+
+ bdrv_replace_child_noperm(child, NULL);
+
+ if (bdrv_get_aio_context(bs) != s->old_child_ctx) {
+ bdrv_try_set_aio_context(bs, s->old_child_ctx, &error_abort);
}
- child = g_new(BdrvChild, 1);
- *child = (BdrvChild) {
+ if (bdrv_child_get_parent_aio_context(child) != s->old_parent_ctx) {
+ GSList *ignore = g_slist_prepend(NULL, child);
+
+ child->klass->can_set_aio_ctx(child, s->old_parent_ctx, &ignore,
+ &error_abort);
+ g_slist_free(ignore);
+ ignore = g_slist_prepend(NULL, child);
+ child->klass->set_aio_ctx(child, s->old_parent_ctx, &ignore);
+
+ g_slist_free(ignore);
+ }
+
+ bdrv_unref(bs);
+ bdrv_remove_empty_child(child);
+ *s->child = NULL;
+}
+
+static TransactionActionDrv bdrv_attach_child_common_drv = {
+ .abort = bdrv_attach_child_common_abort,
+};
+
+/*
+ * Common part of attoching bdrv child to bs or to blk or to job
+ */
+static int bdrv_attach_child_common(BlockDriverState *child_bs,
+ const char *child_name,
+ const BdrvChildClass *child_class,
+ BdrvChildRole child_role,
+ uint64_t perm, uint64_t shared_perm,
+ void *opaque, BdrvChild **child,
+ Transaction *tran, Error **errp)
+{
+ BdrvChild *new_child;
+ AioContext *parent_ctx;
+ AioContext *child_ctx = bdrv_get_aio_context(child_bs);
+
+ assert(child);
+ assert(*child == NULL);
+
+ new_child = g_new(BdrvChild, 1);
+ *new_child = (BdrvChild) {
.bs = NULL,
.name = g_strdup(child_name),
.klass = child_class,
@@ -2961,37 +2997,92 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
.opaque = opaque,
};
- ctx = bdrv_child_get_parent_aio_context(child);
-
- /* If the AioContexts don't match, first try to move the subtree of
+ /*
+ * If the AioContexts don't match, first try to move the subtree of
* child_bs into the AioContext of the new parent. If this doesn't work,
- * try moving the parent into the AioContext of child_bs instead. */
- if (bdrv_get_aio_context(child_bs) != ctx) {
- ret = bdrv_try_set_aio_context(child_bs, ctx, &local_err);
+ * try moving the parent into the AioContext of child_bs instead.
+ */
+ parent_ctx = bdrv_child_get_parent_aio_context(new_child);
+ if (child_ctx != parent_ctx) {
+ Error *local_err = NULL;
+ int ret = bdrv_try_set_aio_context(child_bs, parent_ctx, &local_err);
+
if (ret < 0 && child_class->can_set_aio_ctx) {
- GSList *ignore = g_slist_prepend(NULL, child);
- ctx = bdrv_get_aio_context(child_bs);
- if (child_class->can_set_aio_ctx(child, ctx, &ignore, NULL)) {
+ GSList *ignore = g_slist_prepend(NULL, new_child);
+ if (child_class->can_set_aio_ctx(new_child, child_ctx, &ignore,
+ NULL))
+ {
error_free(local_err);
ret = 0;
g_slist_free(ignore);
- ignore = g_slist_prepend(NULL, child);
- child_class->set_aio_ctx(child, ctx, &ignore);
+ ignore = g_slist_prepend(NULL, new_child);
+ child_class->set_aio_ctx(new_child, child_ctx, &ignore);
}
g_slist_free(ignore);
}
+
if (ret < 0) {
error_propagate(errp, local_err);
- g_free(child);
- bdrv_abort_perm_update(child_bs);
- bdrv_unref(child_bs);
- return NULL;
+ bdrv_remove_empty_child(new_child);
+ return ret;
}
}
- /* This performs the matching bdrv_set_perm() for the above check. */
- bdrv_replace_child(child, child_bs);
+ bdrv_ref(child_bs);
+ bdrv_replace_child_noperm(new_child, child_bs);
+
+ *child = new_child;
+ BdrvAttachChildCommonState *s = g_new(BdrvAttachChildCommonState, 1);
+ *s = (BdrvAttachChildCommonState) {
+ .child = child,
+ .old_parent_ctx = parent_ctx,
+ .old_child_ctx = child_ctx,
+ };
+ tran_add(tran, &bdrv_attach_child_common_drv, s);
+
+ return 0;
+}
+
+static void bdrv_detach_child(BdrvChild *child)
+{
+ bdrv_replace_child(child, NULL);
+ bdrv_remove_empty_child(child);
+}
+
+/*
+ * This function steals the reference to child_bs from the caller.
+ * That reference is later dropped by bdrv_root_unref_child().
+ *
+ * On failure NULL is returned, errp is set and the reference to
+ * child_bs is also dropped.
+ *
+ * The caller must hold the AioContext lock @child_bs, but not that of @ctx
+ * (unless @child_bs is already in @ctx).
+ */
+BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
+ const char *child_name,
+ const BdrvChildClass *child_class,
+ BdrvChildRole child_role,
+ uint64_t perm, uint64_t shared_perm,
+ void *opaque, Error **errp)
+{
+ int ret;
+ BdrvChild *child = NULL;
+ Transaction *tran = tran_new();
+
+ ret = bdrv_attach_child_common(child_bs, child_name, child_class,
+ child_role, perm, shared_perm, opaque,
+ &child, tran, errp);
+ if (ret < 0) {
+ bdrv_unref(child_bs);
+ return NULL;
+ }
+
+ ret = bdrv_refresh_perms(child_bs, errp);
+ tran_finalize(tran, ret);
+
+ bdrv_unref(child_bs);
return child;
}
@@ -3033,16 +3124,6 @@ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
return child;
}
-static void bdrv_detach_child(BdrvChild *child)
-{
- QLIST_SAFE_REMOVE(child, next);
-
- bdrv_replace_child(child, NULL);
-
- g_free(child->name);
- g_free(child);
-}
-
/* Callers must ensure that child->frozen is false. */
void bdrv_root_unref_child(BdrvChild *child)
{
--
2.29.2
Am 17.03.2021 um 15:35 hat Vladimir Sementsov-Ogievskiy geschrieben:
> Split out no-perm part of bdrv_root_attach_child() into separate
> transaction action. bdrv_root_attach_child() now moves to new
> permission update paradigm: first update graph relations then update
> permissions.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
> block.c | 189 ++++++++++++++++++++++++++++++++++++++++----------------
> 1 file changed, 135 insertions(+), 54 deletions(-)
>
> diff --git a/block.c b/block.c
> index 98ff44dbf7..b6bdc534d2 100644
> --- a/block.c
> +++ b/block.c
> @@ -2921,37 +2921,73 @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
> }
> }
>
> -/*
> - * This function steals the reference to child_bs from the caller.
> - * That reference is later dropped by bdrv_root_unref_child().
> - *
> - * On failure NULL is returned, errp is set and the reference to
> - * child_bs is also dropped.
> - *
> - * The caller must hold the AioContext lock @child_bs, but not that of @ctx
> - * (unless @child_bs is already in @ctx).
> - */
> -BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
> - const char *child_name,
> - const BdrvChildClass *child_class,
> - BdrvChildRole child_role,
> - uint64_t perm, uint64_t shared_perm,
> - void *opaque, Error **errp)
> +static void bdrv_remove_empty_child(BdrvChild *child)
> {
> - BdrvChild *child;
> - Error *local_err = NULL;
> - int ret;
> - AioContext *ctx;
> + assert(!child->bs);
> + QLIST_SAFE_REMOVE(child, next);
> + g_free(child->name);
> + g_free(child);
> +}
>
> - ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, errp);
> - if (ret < 0) {
> - bdrv_abort_perm_update(child_bs);
> - bdrv_unref(child_bs);
> - return NULL;
> +typedef struct BdrvAttachChildCommonState {
> + BdrvChild **child;
> + AioContext *old_parent_ctx;
> + AioContext *old_child_ctx;
> +} BdrvAttachChildCommonState;
> +
> +static void bdrv_attach_child_common_abort(void *opaque)
> +{
> + BdrvAttachChildCommonState *s = opaque;
> + BdrvChild *child = *s->child;
> + BlockDriverState *bs = child->bs;
> +
> + bdrv_replace_child_noperm(child, NULL);
> +
> + if (bdrv_get_aio_context(bs) != s->old_child_ctx) {
> + bdrv_try_set_aio_context(bs, s->old_child_ctx, &error_abort);
> }
>
> - child = g_new(BdrvChild, 1);
> - *child = (BdrvChild) {
> + if (bdrv_child_get_parent_aio_context(child) != s->old_parent_ctx) {
> + GSList *ignore = g_slist_prepend(NULL, child);
> +
> + child->klass->can_set_aio_ctx(child, s->old_parent_ctx, &ignore,
> + &error_abort);
> + g_slist_free(ignore);
> + ignore = g_slist_prepend(NULL, child);
> + child->klass->set_aio_ctx(child, s->old_parent_ctx, &ignore);
> +
> + g_slist_free(ignore);
> + }
> +
> + bdrv_unref(bs);
> + bdrv_remove_empty_child(child);
> + *s->child = NULL;
> +}
> +
> +static TransactionActionDrv bdrv_attach_child_common_drv = {
> + .abort = bdrv_attach_child_common_abort,
> +};
> +
> +/*
> + * Common part of attoching bdrv child to bs or to blk or to job
> + */
> +static int bdrv_attach_child_common(BlockDriverState *child_bs,
> + const char *child_name,
> + const BdrvChildClass *child_class,
> + BdrvChildRole child_role,
> + uint64_t perm, uint64_t shared_perm,
> + void *opaque, BdrvChild **child,
> + Transaction *tran, Error **errp)
> +{
> + BdrvChild *new_child;
> + AioContext *parent_ctx;
> + AioContext *child_ctx = bdrv_get_aio_context(child_bs);
> +
> + assert(child);
> + assert(*child == NULL);
> +
> + new_child = g_new(BdrvChild, 1);
> + *new_child = (BdrvChild) {
> .bs = NULL,
> .name = g_strdup(child_name),
> .klass = child_class,
> @@ -2961,37 +2997,92 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
> .opaque = opaque,
> };
>
> - ctx = bdrv_child_get_parent_aio_context(child);
> -
> - /* If the AioContexts don't match, first try to move the subtree of
> + /*
> + * If the AioContexts don't match, first try to move the subtree of
> * child_bs into the AioContext of the new parent. If this doesn't work,
> - * try moving the parent into the AioContext of child_bs instead. */
> - if (bdrv_get_aio_context(child_bs) != ctx) {
> - ret = bdrv_try_set_aio_context(child_bs, ctx, &local_err);
> + * try moving the parent into the AioContext of child_bs instead.
> + */
> + parent_ctx = bdrv_child_get_parent_aio_context(new_child);
> + if (child_ctx != parent_ctx) {
> + Error *local_err = NULL;
> + int ret = bdrv_try_set_aio_context(child_bs, parent_ctx, &local_err);
> +
> if (ret < 0 && child_class->can_set_aio_ctx) {
> - GSList *ignore = g_slist_prepend(NULL, child);
> - ctx = bdrv_get_aio_context(child_bs);
> - if (child_class->can_set_aio_ctx(child, ctx, &ignore, NULL)) {
> + GSList *ignore = g_slist_prepend(NULL, new_child);
> + if (child_class->can_set_aio_ctx(new_child, child_ctx, &ignore,
> + NULL))
> + {
> error_free(local_err);
> ret = 0;
> g_slist_free(ignore);
> - ignore = g_slist_prepend(NULL, child);
> - child_class->set_aio_ctx(child, ctx, &ignore);
> + ignore = g_slist_prepend(NULL, new_child);
> + child_class->set_aio_ctx(new_child, child_ctx, &ignore);
> }
> g_slist_free(ignore);
> }
> +
> if (ret < 0) {
> error_propagate(errp, local_err);
> - g_free(child);
> - bdrv_abort_perm_update(child_bs);
> - bdrv_unref(child_bs);
> - return NULL;
> + bdrv_remove_empty_child(new_child);
> + return ret;
> }
> }
>
> - /* This performs the matching bdrv_set_perm() for the above check. */
> - bdrv_replace_child(child, child_bs);
> + bdrv_ref(child_bs);
> + bdrv_replace_child_noperm(new_child, child_bs);
> +
> + *child = new_child;
>
> + BdrvAttachChildCommonState *s = g_new(BdrvAttachChildCommonState, 1);
> + *s = (BdrvAttachChildCommonState) {
> + .child = child,
> + .old_parent_ctx = parent_ctx,
> + .old_child_ctx = child_ctx,
> + };
> + tran_add(tran, &bdrv_attach_child_common_drv, s);
Who frees s? Should bdrv_attach_child_common_drv have a .clean?
> +
> + return 0;
> +}
Kevin
26.04.2021 19:14, Kevin Wolf wrote:
> Am 17.03.2021 um 15:35 hat Vladimir Sementsov-Ogievskiy geschrieben:
>> Split out no-perm part of bdrv_root_attach_child() into separate
>> transaction action. bdrv_root_attach_child() now moves to new
>> permission update paradigm: first update graph relations then update
>> permissions.
>>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
>> ---
>> block.c | 189 ++++++++++++++++++++++++++++++++++++++++----------------
>> 1 file changed, 135 insertions(+), 54 deletions(-)
>>
>> diff --git a/block.c b/block.c
>> index 98ff44dbf7..b6bdc534d2 100644
>> --- a/block.c
>> +++ b/block.c
>> @@ -2921,37 +2921,73 @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
>> }
>> }
>>
>> -/*
>> - * This function steals the reference to child_bs from the caller.
>> - * That reference is later dropped by bdrv_root_unref_child().
>> - *
>> - * On failure NULL is returned, errp is set and the reference to
>> - * child_bs is also dropped.
>> - *
>> - * The caller must hold the AioContext lock @child_bs, but not that of @ctx
>> - * (unless @child_bs is already in @ctx).
>> - */
>> -BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
>> - const char *child_name,
>> - const BdrvChildClass *child_class,
>> - BdrvChildRole child_role,
>> - uint64_t perm, uint64_t shared_perm,
>> - void *opaque, Error **errp)
>> +static void bdrv_remove_empty_child(BdrvChild *child)
>> {
>> - BdrvChild *child;
>> - Error *local_err = NULL;
>> - int ret;
>> - AioContext *ctx;
>> + assert(!child->bs);
>> + QLIST_SAFE_REMOVE(child, next);
>> + g_free(child->name);
>> + g_free(child);
>> +}
>>
>> - ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, errp);
>> - if (ret < 0) {
>> - bdrv_abort_perm_update(child_bs);
>> - bdrv_unref(child_bs);
>> - return NULL;
>> +typedef struct BdrvAttachChildCommonState {
>> + BdrvChild **child;
>> + AioContext *old_parent_ctx;
>> + AioContext *old_child_ctx;
>> +} BdrvAttachChildCommonState;
>> +
>> +static void bdrv_attach_child_common_abort(void *opaque)
>> +{
>> + BdrvAttachChildCommonState *s = opaque;
>> + BdrvChild *child = *s->child;
>> + BlockDriverState *bs = child->bs;
>> +
>> + bdrv_replace_child_noperm(child, NULL);
>> +
>> + if (bdrv_get_aio_context(bs) != s->old_child_ctx) {
>> + bdrv_try_set_aio_context(bs, s->old_child_ctx, &error_abort);
>> }
>>
>> - child = g_new(BdrvChild, 1);
>> - *child = (BdrvChild) {
>> + if (bdrv_child_get_parent_aio_context(child) != s->old_parent_ctx) {
>> + GSList *ignore = g_slist_prepend(NULL, child);
>> +
>> + child->klass->can_set_aio_ctx(child, s->old_parent_ctx, &ignore,
>> + &error_abort);
>> + g_slist_free(ignore);
>> + ignore = g_slist_prepend(NULL, child);
>> + child->klass->set_aio_ctx(child, s->old_parent_ctx, &ignore);
>> +
>> + g_slist_free(ignore);
>> + }
>> +
>> + bdrv_unref(bs);
>> + bdrv_remove_empty_child(child);
>> + *s->child = NULL;
>> +}
>> +
>> +static TransactionActionDrv bdrv_attach_child_common_drv = {
>> + .abort = bdrv_attach_child_common_abort,
>> +};
>> +
>> +/*
>> + * Common part of attoching bdrv child to bs or to blk or to job
>> + */
>> +static int bdrv_attach_child_common(BlockDriverState *child_bs,
>> + const char *child_name,
>> + const BdrvChildClass *child_class,
>> + BdrvChildRole child_role,
>> + uint64_t perm, uint64_t shared_perm,
>> + void *opaque, BdrvChild **child,
>> + Transaction *tran, Error **errp)
>> +{
>> + BdrvChild *new_child;
>> + AioContext *parent_ctx;
>> + AioContext *child_ctx = bdrv_get_aio_context(child_bs);
>> +
>> + assert(child);
>> + assert(*child == NULL);
>> +
>> + new_child = g_new(BdrvChild, 1);
>> + *new_child = (BdrvChild) {
>> .bs = NULL,
>> .name = g_strdup(child_name),
>> .klass = child_class,
>> @@ -2961,37 +2997,92 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
>> .opaque = opaque,
>> };
>>
>> - ctx = bdrv_child_get_parent_aio_context(child);
>> -
>> - /* If the AioContexts don't match, first try to move the subtree of
>> + /*
>> + * If the AioContexts don't match, first try to move the subtree of
>> * child_bs into the AioContext of the new parent. If this doesn't work,
>> - * try moving the parent into the AioContext of child_bs instead. */
>> - if (bdrv_get_aio_context(child_bs) != ctx) {
>> - ret = bdrv_try_set_aio_context(child_bs, ctx, &local_err);
>> + * try moving the parent into the AioContext of child_bs instead.
>> + */
>> + parent_ctx = bdrv_child_get_parent_aio_context(new_child);
>> + if (child_ctx != parent_ctx) {
>> + Error *local_err = NULL;
>> + int ret = bdrv_try_set_aio_context(child_bs, parent_ctx, &local_err);
>> +
>> if (ret < 0 && child_class->can_set_aio_ctx) {
>> - GSList *ignore = g_slist_prepend(NULL, child);
>> - ctx = bdrv_get_aio_context(child_bs);
>> - if (child_class->can_set_aio_ctx(child, ctx, &ignore, NULL)) {
>> + GSList *ignore = g_slist_prepend(NULL, new_child);
>> + if (child_class->can_set_aio_ctx(new_child, child_ctx, &ignore,
>> + NULL))
>> + {
>> error_free(local_err);
>> ret = 0;
>> g_slist_free(ignore);
>> - ignore = g_slist_prepend(NULL, child);
>> - child_class->set_aio_ctx(child, ctx, &ignore);
>> + ignore = g_slist_prepend(NULL, new_child);
>> + child_class->set_aio_ctx(new_child, child_ctx, &ignore);
>> }
>> g_slist_free(ignore);
>> }
>> +
>> if (ret < 0) {
>> error_propagate(errp, local_err);
>> - g_free(child);
>> - bdrv_abort_perm_update(child_bs);
>> - bdrv_unref(child_bs);
>> - return NULL;
>> + bdrv_remove_empty_child(new_child);
>> + return ret;
>> }
>> }
>>
>> - /* This performs the matching bdrv_set_perm() for the above check. */
>> - bdrv_replace_child(child, child_bs);
>> + bdrv_ref(child_bs);
>> + bdrv_replace_child_noperm(new_child, child_bs);
>> +
>> + *child = new_child;
>>
>> + BdrvAttachChildCommonState *s = g_new(BdrvAttachChildCommonState, 1);
>> + *s = (BdrvAttachChildCommonState) {
>> + .child = child,
>> + .old_parent_ctx = parent_ctx,
>> + .old_child_ctx = child_ctx,
>> + };
>> + tran_add(tran, &bdrv_attach_child_common_drv, s);
>
> Who frees s? Should bdrv_attach_child_common_drv have a .clean?
>
Hmm, yes, looks like ".clean = g_free" missed.
--
Best regards,
Vladimir
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