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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>
This commit is contained in:
Fam Zheng 2014-09-11 13:14:00 +08:00 committed by Stefan Hajnoczi
parent 095e4fa4b5
commit bb00021de0
4 changed files with 12 additions and 6 deletions
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6
block.c
View File

@ -1200,7 +1200,7 @@ void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd)
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 @@ int bdrv_commit(BlockDriverState *bs)
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;
}

6
blockdev.c
View File

@ -2218,7 +2218,7 @@ void qmp_block_commit(const char *device,
/* drain all i/o before commits */
bdrv_drain_all();
if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT, errp)) {
if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, errp)) {
goto out;
}
@ -2251,6 +2251,10 @@ void qmp_block_commit(const char *device,
assert(bdrv_get_aio_context(base_bs) == aio_context);
if (bdrv_op_is_blocked(base_bs, BLOCK_OP_TYPE_COMMIT_TARGET, errp)) {
goto out;
}
/* Do not allow attempts to commit an image into itself */
if (top_bs == base_bs) {
error_setg(errp, "cannot commit an image into itself");

3
hw/block/dataplane/virtio-blk.c
View File

@ -198,7 +198,8 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *conf,
blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_DRIVE_DEL, s->blocker);
blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_BACKUP_SOURCE, s->blocker);
blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_CHANGE, s->blocker);
blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_COMMIT, s->blocker);
blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_COMMIT_SOURCE, s->blocker);
blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_COMMIT_TARGET, s->blocker);
blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_EJECT, s->blocker);
blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT, s->blocker);
blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT, s->blocker);

3
include/block/block.h
View File

@ -133,7 +133,8 @@ typedef enum BlockOpType {
BLOCK_OP_TYPE_BACKUP_SOURCE,
BLOCK_OP_TYPE_BACKUP_TARGET,
BLOCK_OP_TYPE_CHANGE,
BLOCK_OP_TYPE_COMMIT,
BLOCK_OP_TYPE_COMMIT_SOURCE,
BLOCK_OP_TYPE_COMMIT_TARGET,
BLOCK_OP_TYPE_DATAPLANE,
BLOCK_OP_TYPE_DRIVE_DEL,
BLOCK_OP_TYPE_EJECT,