This lets us hook into drained_begin and drained_end requests from the
backend level, which is particularly useful for making sure that all
jobs associated with a particular node (whether the source or the target)
receive a drain request.
Suggested-by: Kevin Wolf <kw...@redhat.com>
Signed-off-by: John Snow <js...@redhat.com>
--
RFC topics:
- BlkDevOps is traditionally only for Qdev devices, and a BlockJob is not
currently a 'device'... Do we want to loosen this restriction, find another
way to deliver callbacks to BlockJobs attached to BlkBackends, or do something
crazy like make a BlockJob device object?
struct JobDevice {
DeviceState parent_obj;
BlockJob *job;
} ...??
- Not so sure about leaving the initial job refcount at 1, since we are giving
away a handle to this job as dev_opaque. By incrementing it to 2, however,
it's not clear whose responsibility it is to decrement it again.
Signed-off-by: John Snow <js...@redhat.com>
---
blockjob.c | 34 +++++++++++++++++++++++++++++-----
1 file changed, 29 insertions(+), 5 deletions(-)
diff --git a/blockjob.c b/blockjob.c
index 6d08ce5..0542677 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -68,6 +68,23 @@ static const BdrvChildRole child_job = {
.stay_at_node = true,
};
+static void block_job_drained_begin(void *opaque)
+{
+ BlockJob *job = opaque;
+ block_job_pause(job);
+}
+
+static void block_job_drained_end(void *opaque)
+{
+ BlockJob *job = opaque;
+ block_job_resume(job);
+}
+
+static const BlockDevOps block_job_dev_ops = {
+ .drained_begin = block_job_drained_begin,
+ .drained_end = block_job_drained_end,
+};
+
BlockJob *block_job_next(BlockJob *job)
{
if (!job) {
@@ -205,11 +222,6 @@ void *block_job_create(const char *job_id, const
BlockJobDriver *driver,
}
job = g_malloc0(driver->instance_size);
- error_setg(&job->blocker, "block device is in use by block job: %s",
- BlockJobType_lookup[driver->job_type]);
- block_job_add_bdrv(job, "main node", bs, 0, BLK_PERM_ALL, &error_abort);
- bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
-
job->driver = driver;
job->id = g_strdup(job_id);
job->blk = blk;
@@ -219,8 +231,20 @@ void *block_job_create(const char *job_id, const
BlockJobDriver *driver,
job->paused = true;
job->pause_count = 1;
job->refcnt = 1;
+ /* RFC: job is now stored both in bs->job and blk->dev_opaque,
+ * but we cannot expect the backend to know how to put down the ref
+ * so it'd be up to this code here to increment it anyway, making it
+ * a bit of a useless exercise. It would be up to us to ensure that
+ * we destruct the blkbackend before putting down our last reference. */
+
+ error_setg(&job->blocker, "block device is in use by block job: %s",
+ BlockJobType_lookup[driver->job_type]);
+ block_job_add_bdrv(job, "main node", bs, 0, BLK_PERM_ALL, &error_abort);
bs->job = job;
+ blk_set_dev_ops(blk, &block_job_dev_ops, job);
+ bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
+
QLIST_INSERT_HEAD(&block_jobs, job, job_list);
blk_add_aio_context_notifier(blk, block_job_attached_aio_context,
--
2.9.3
