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[PULL 18/64] block: Add chain helper functions
From: |
Kevin Wolf |
Subject: |
[PULL 18/64] block: Add chain helper functions |
Date: |
Mon, 7 Sep 2020 13:08:50 +0200 |
From: Max Reitz <mreitz@redhat.com>
Add some helper functions for skipping filters in a chain of block
nodes.
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
include/block/block_int.h | 3 ++
block.c | 62 +++++++++++++++++++++++++++++++++++++++
2 files changed, 65 insertions(+)
diff --git a/include/block/block_int.h b/include/block/block_int.h
index f280a95b26..8205ccaa62 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -1394,6 +1394,9 @@ BdrvChild *bdrv_cow_child(BlockDriverState *bs);
BdrvChild *bdrv_filter_child(BlockDriverState *bs);
BdrvChild *bdrv_filter_or_cow_child(BlockDriverState *bs);
BdrvChild *bdrv_primary_child(BlockDriverState *bs);
+BlockDriverState *bdrv_skip_implicit_filters(BlockDriverState *bs);
+BlockDriverState *bdrv_skip_filters(BlockDriverState *bs);
+BlockDriverState *bdrv_backing_chain_next(BlockDriverState *bs);
static inline BlockDriverState *child_bs(BdrvChild *child)
{
diff --git a/block.c b/block.c
index 9f866e8676..b162142609 100644
--- a/block.c
+++ b/block.c
@@ -7034,3 +7034,65 @@ BdrvChild *bdrv_primary_child(BlockDriverState *bs)
return found;
}
+
+static BlockDriverState *bdrv_do_skip_filters(BlockDriverState *bs,
+ bool stop_on_explicit_filter)
+{
+ BdrvChild *c;
+
+ if (!bs) {
+ return NULL;
+ }
+
+ while (!(stop_on_explicit_filter && !bs->implicit)) {
+ c = bdrv_filter_child(bs);
+ if (!c) {
+ /*
+ * A filter that is embedded in a working block graph must
+ * have a child. Assert this here so this function does
+ * not return a filter node that is not expected by the
+ * caller.
+ */
+ assert(!bs->drv || !bs->drv->is_filter);
+ break;
+ }
+ bs = c->bs;
+ }
+ /*
+ * Note that this treats nodes with bs->drv == NULL as not being
+ * filters (bs->drv == NULL should be replaced by something else
+ * anyway).
+ * The advantage of this behavior is that this function will thus
+ * always return a non-NULL value (given a non-NULL @bs).
+ */
+
+ return bs;
+}
+
+/*
+ * Return the first BDS that has not been added implicitly or that
+ * does not have a filtered child down the chain starting from @bs
+ * (including @bs itself).
+ */
+BlockDriverState *bdrv_skip_implicit_filters(BlockDriverState *bs)
+{
+ return bdrv_do_skip_filters(bs, true);
+}
+
+/*
+ * Return the first BDS that does not have a filtered child down the
+ * chain starting from @bs (including @bs itself).
+ */
+BlockDriverState *bdrv_skip_filters(BlockDriverState *bs)
+{
+ return bdrv_do_skip_filters(bs, false);
+}
+
+/*
+ * For a backing chain, return the first non-filter backing image of
+ * the first non-filter image.
+ */
+BlockDriverState *bdrv_backing_chain_next(BlockDriverState *bs)
+{
+ return bdrv_skip_filters(bdrv_cow_bs(bdrv_skip_filters(bs)));
+}
--
2.25.4
- [PULL 05/64] block/nvme: Define INDEX macros to ease code review, (continued)
- [PULL 05/64] block/nvme: Define INDEX macros to ease code review, Kevin Wolf, 2020/09/07
- [PULL 09/64] block/nvme: Use union of NvmeIdCtrl / NvmeIdNs structures, Kevin Wolf, 2020/09/07
- [PULL 10/64] block/nvme: Replace qemu_try_blockalign0 by qemu_try_blockalign/memset, Kevin Wolf, 2020/09/07
- [PULL 11/64] block/nvme: Replace qemu_try_blockalign(bs) by qemu_try_memalign(pg_sz), Kevin Wolf, 2020/09/07
- [PULL 12/64] block/nvme: Simplify nvme_init_queue() arguments, Kevin Wolf, 2020/09/07
- [PULL 13/64] block/nvme: Replace BDRV_POLL_WHILE by AIO_WAIT_WHILE, Kevin Wolf, 2020/09/07
- [PULL 08/64] block/nvme: Rename local variable, Kevin Wolf, 2020/09/07
- [PULL 14/64] block/nvme: Simplify nvme_create_queue_pair() arguments, Kevin Wolf, 2020/09/07
- [PULL 15/64] block/nvme: Extract nvme_poll_queue(), Kevin Wolf, 2020/09/07
- [PULL 17/64] block: Add child access functions, Kevin Wolf, 2020/09/07
- [PULL 18/64] block: Add chain helper functions,
Kevin Wolf <=
- [PULL 19/64] block: bdrv_cow_child() for bdrv_has_zero_init(), Kevin Wolf, 2020/09/07
- [PULL 16/64] block/nvme: Use an array of EventNotifier, Kevin Wolf, 2020/09/07
- [PULL 20/64] block: bdrv_set_backing_hd() is about bs->backing, Kevin Wolf, 2020/09/07
- [PULL 21/64] block: Include filters when freezing backing chain, Kevin Wolf, 2020/09/07
- [PULL 23/64] block: Add bdrv_supports_compressed_writes(), Kevin Wolf, 2020/09/07
- [PULL 24/64] throttle: Support compressed writes, Kevin Wolf, 2020/09/07
- [PULL 26/64] block: Use bdrv_filter_(bs|child) where obvious, Kevin Wolf, 2020/09/07
- [PULL 22/64] block: Drop bdrv_is_encrypted(), Kevin Wolf, 2020/09/07
- [PULL 27/64] block: Use CAFs in block status functions, Kevin Wolf, 2020/09/07
- [PULL 25/64] copy-on-read: Support compressed writes, Kevin Wolf, 2020/09/07