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authorKevin Wolf <kwolf@redhat.com>2017-12-06 17:05:44 +0100
committerKevin Wolf <kwolf@redhat.com>2017-12-22 15:05:32 +0100
commitb0165585900f050f403cecba9d89adeccf35dd6c (patch)
tree82a19acb79e687005a43bdaed32f8c34fdcde05f
parent0152bf400fe3ca7facb382683bfcccda70ebf51a (diff)
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block: Add bdrv_subtree_drained_begin/end()
bdrv_drained_begin() waits for the completion of requests in the whole subtree, but it only actually keeps its immediate bs parameter quiesced until bdrv_drained_end(). Add a version that keeps the whole subtree drained. As of this commit, graph changes cannot be allowed during a subtree drained section, but this will be fixed soon. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
-rw-r--r--block/io.c54
-rw-r--r--include/block/block.h13
2 files changed, 56 insertions, 11 deletions
diff --git a/block/io.c b/block/io.c
index 09de0a9..6befef1 100644
--- a/block/io.c
+++ b/block/io.c
@@ -145,6 +145,7 @@ typedef struct {
BlockDriverState *bs;
bool done;
bool begin;
+ bool recursive;
BdrvChild *parent;
} BdrvCoDrainData;
@@ -218,8 +219,10 @@ static bool bdrv_drain_recurse(BlockDriverState *bs)
return waited;
}
-static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent);
-static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent);
+static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive,
+ BdrvChild *parent);
+static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive,
+ BdrvChild *parent);
static void bdrv_co_drain_bh_cb(void *opaque)
{
@@ -229,9 +232,9 @@ static void bdrv_co_drain_bh_cb(void *opaque)
bdrv_dec_in_flight(bs);
if (data->begin) {
- bdrv_do_drained_begin(bs, data->parent);
+ bdrv_do_drained_begin(bs, data->recursive, data->parent);
} else {
- bdrv_do_drained_end(bs, data->parent);
+ bdrv_do_drained_end(bs, data->recursive, data->parent);
}
data->done = true;
@@ -239,7 +242,8 @@ static void bdrv_co_drain_bh_cb(void *opaque)
}
static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,
- bool begin, BdrvChild *parent)
+ bool begin, bool recursive,
+ BdrvChild *parent)
{
BdrvCoDrainData data;
@@ -253,6 +257,7 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,
.bs = bs,
.done = false,
.begin = begin,
+ .recursive = recursive,
.parent = parent,
};
bdrv_inc_in_flight(bs);
@@ -265,10 +270,13 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,
assert(data.done);
}
-static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent)
+static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive,
+ BdrvChild *parent)
{
+ BdrvChild *child, *next;
+
if (qemu_in_coroutine()) {
- bdrv_co_yield_to_drain(bs, true, parent);
+ bdrv_co_yield_to_drain(bs, true, recursive, parent);
return;
}
@@ -280,19 +288,32 @@ static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent)
bdrv_parent_drained_begin(bs, parent);
bdrv_drain_invoke(bs, true, false);
bdrv_drain_recurse(bs);
+
+ if (recursive) {
+ QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
+ bdrv_do_drained_begin(child->bs, true, child);
+ }
+ }
}
void bdrv_drained_begin(BlockDriverState *bs)
{
- bdrv_do_drained_begin(bs, NULL);
+ bdrv_do_drained_begin(bs, false, NULL);
+}
+
+void bdrv_subtree_drained_begin(BlockDriverState *bs)
+{
+ bdrv_do_drained_begin(bs, true, NULL);
}
-static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent)
+static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive,
+ BdrvChild *parent)
{
+ BdrvChild *child, *next;
int old_quiesce_counter;
if (qemu_in_coroutine()) {
- bdrv_co_yield_to_drain(bs, false, parent);
+ bdrv_co_yield_to_drain(bs, false, recursive, parent);
return;
}
assert(bs->quiesce_counter > 0);
@@ -304,11 +325,22 @@ static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent)
if (old_quiesce_counter == 1) {
aio_enable_external(bdrv_get_aio_context(bs));
}
+
+ if (recursive) {
+ QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
+ bdrv_do_drained_end(child->bs, true, child);
+ }
+ }
}
void bdrv_drained_end(BlockDriverState *bs)
{
- bdrv_do_drained_end(bs, NULL);
+ bdrv_do_drained_end(bs, false, NULL);
+}
+
+void bdrv_subtree_drained_end(BlockDriverState *bs)
+{
+ bdrv_do_drained_end(bs, true, NULL);
}
/*
diff --git a/include/block/block.h b/include/block/block.h
index 60c5d11..de9c5a2 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -608,12 +608,25 @@ void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore);
void bdrv_drained_begin(BlockDriverState *bs);
/**
+ * Like bdrv_drained_begin, but recursively begins a quiesced section for
+ * exclusive access to all child nodes as well.
+ *
+ * Graph changes are not allowed during a subtree drain section.
+ */
+void bdrv_subtree_drained_begin(BlockDriverState *bs);
+
+/**
* bdrv_drained_end:
*
* End a quiescent section started by bdrv_drained_begin().
*/
void bdrv_drained_end(BlockDriverState *bs);
+/**
+ * End a quiescent section started by bdrv_subtree_drained_begin().
+ */
+void bdrv_subtree_drained_end(BlockDriverState *bs);
+
void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
Error **errp);
void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);