Commit e5182c1c authored Jul 03, 2019 by Max Reitz

block: Add BDS.never_freeze



The commit and the mirror block job must be able to drop their filter
node at any point.  However, this will not be possible if any of the
BdrvChild links to them is frozen.  Therefore, we need to prevent them
from ever becoming frozen.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20190703172813.6868-2-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

parent 95667c3b

block.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -4416,6 +4416,14 @@ int bdrv_freeze_backing_chain(BlockDriverState bs, BlockDriverState base,
		return -EPERM;
		}

		for (i = bs; i != base; i = backing_bs(i)) {
		if (i->backing && backing_bs(i)->never_freeze) {
		error_setg(errp, "Cannot freeze '%s' link to '%s'",
		i->backing->name, backing_bs(i)->node_name);
		return -EPERM;
		}
		}

		for (i = bs; i != base; i = backing_bs(i)) {
		if (i->backing) {
		i->backing->frozen = true;

block/commit.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -298,6 +298,10 @@ void commit_start(const char job_id, BlockDriverState bs,
		if (!filter_node_name) {
		commit_top_bs->implicit = true;
		}

		/* So that we can always drop this node */
		commit_top_bs->never_freeze = true;

		commit_top_bs->total_sectors = top->total_sectors;

		bdrv_append(commit_top_bs, top, &local_err);

block/mirror.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -1551,6 +1551,10 @@ static BlockJob *mirror_start_job(
		if (!filter_node_name) {
		mirror_top_bs->implicit = true;
		}

		/* So that we can always drop this node */
		mirror_top_bs->never_freeze = true;

		mirror_top_bs->total_sectors = bs->total_sectors;
		mirror_top_bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED;
		mirror_top_bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED \|

include/block/block_int.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -885,6 +885,9 @@ struct BlockDriverState {

		/* Only read/written by whoever has set active_flush_req to true. */
		unsigned int flushed_gen; /* Flushed write generation */

		/* BdrvChild links to this node may never be frozen */
		bool never_freeze;
		};

		struct BlockBackendRootState {