commit bb00021de0b5908bc2c3ca467ad9a2b0c9c36459
author Fam Zheng <famz@redhat.com> Thu Sep 11 13:14:00 2014 +0800
committer Stefan Hajnoczi <stefanha@redhat.com> Tue Jan 13 13:43:29 2015 +0000
tree 87cc009a3e868b3bd2dac421dcdfb8bf6043cbda
parent 095e4fa4b56cf511cb41005872eeace9a2f24582

block: Split BLOCK_OP_TYPE_COMMIT to BLOCK_OP_TYPE_COMMIT_{SOURCE, TARGET}

Like BLOCK_OP_TYPE_BACKUP_SOURCE and BLOCK_OP_TYPE_BACKUP_TARGET,
block-commit involves two asymmetric devices.

This change is not user-visible (yet), because commit only works with
device names.

But once we enable backing reference in blockdev-add, or specifying
node-name in block-commit command, we don't want the user to start two
commit jobs on the same backing chain, which will corrupt things because
of the final bdrv_swap.

Before we have per category blockers, splitting this type is still
better.

[Resolved virtio-blk dataplane conflict by replacing
BLOCK_OP_TYPE_COMMIT with both BLOCK_OP_TYPE_COMMIT_{SOURCE, TARGET}.
They are safe since the block job runs in the same AioContext as the
dataplane IOThread.
--Stefan]

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

block.c

diff --git a/block.c b/block.c
index 371d0f6..cbe4a32 100644
--- a/block.c
+++ b/block.c
@@ -1200,7 +1200,7 @@
 
     bdrv_op_block_all(bs->backing_hd, bs->backing_blocker);
     /* Otherwise we won't be able to commit due to check in bdrv_commit */
-    bdrv_op_unblock(bs->backing_hd, BLOCK_OP_TYPE_COMMIT,
+    bdrv_op_unblock(bs->backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET,
                     bs->backing_blocker);
 out:
     bdrv_refresh_limits(bs, NULL);
@@ -2216,8 +2216,8 @@
         return -ENOTSUP;
     }
 
-    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT, NULL) ||
-        bdrv_op_is_blocked(bs->backing_hd, BLOCK_OP_TYPE_COMMIT, NULL)) {
+    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, NULL) ||
+        bdrv_op_is_blocked(bs->backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET, NULL)) {
         return -EBUSY;
     }