Re: [Qemu-block] [RFC v4 10/21] blockjobs: add NULL state

[Kevin Wolf]

Am 24.02.2018 um 00:51 hat John Snow geschrieben:
> Add a new state that specifically demarcates when we begin to permanently
> demolish a job after it has performed all work. This makes the transition
> explicit in the STM table and highlights conditions under which a job may
> be demolished.
> 
> 
> Transitions:
> Created   -> Null: Early failure event before the job is started
> Concluded -> Null: Standard transition.
> 
> Verbs:
> None. This should not ever be visible to the monitor.
> 
>  +-+
>  |UNDEFINED|
>  +--+--+
> |
>  +--v+
>  |CREATED+--+
>  +--++  |
> |   |
>  +--v+ +--+ |
>+-+RUNNING<->PAUSED| |
>| +--+-+--+ +--+ |
>|| | |
>|| +--+  |
>|||  |
>| +--v--+   +---+ |  |
>+-+READY<--->STANDBY| |  |
>| +--+--+   +---+ |  |
>|||  |
> +--v-+   +--v--+ |  |
> |ABORTING+--->CONCLUDED<-+  |
> ++   +--+--+|
> |   |
>  +--v-+ |
>  |NULL<-+
>  ++
> 
> Signed-off-by: John Snow 

The commit message does not match the code:

> @@ -423,6 +424,7 @@ static void block_job_completed_single(BlockJob *job)
>  QLIST_REMOVE(job, txn_list);
>  block_job_txn_unref(job->txn);
>  block_job_event_concluded(job);
> +block_job_state_transition(job, BLOCK_JOB_STATUS_NULL);
>  block_job_unref(job);
>  }
>  
> @@ -734,9 +736,6 @@ static void block_job_event_completed(BlockJob *job, 
> const char *msg)
>  
>  static void block_job_event_concluded(BlockJob *job)
>  {
> -if (block_job_is_internal(job) || !job->manual) {
> -return;
> -}
>  block_job_state_transition(job, BLOCK_JOB_STATUS_CONCLUDED);
>  }

Any job that transition to NULL goes first through CONCLUDED. There is
no way to reach NULL directly from CREATED.

The second hunk addresses my comment in the previous patch, so it should
probably be squashed in there.

Kevin

[Qemu-block] [RFC v4 10/21] blockjobs: add NULL state

[John Snow]

Add a new state that specifically demarcates when we begin to permanently
demolish a job after it has performed all work. This makes the transition
explicit in the STM table and highlights conditions under which a job may
be demolished.


Transitions:
Created   -> Null: Early failure event before the job is started
Concluded -> Null: Standard transition.

Verbs:
None. This should not ever be visible to the monitor.

 +-+
 |UNDEFINED|
 +--+--+
|
 +--v+
 |CREATED+--+
 +--++  |
|   |
 +--v+ +--+ |
   +-+RUNNING<->PAUSED| |
   | +--+-+--+ +--+ |
   || | |
   || +--+  |
   |||  |
   | +--v--+   +---+ |  |
   +-+READY<--->STANDBY| |  |
   | +--+--+   +---+ |  |
   |||  |
+--v-+   +--v--+ |  |
|ABORTING+--->CONCLUDED<-+  |
++   +--+--+|
|   |
 +--v-+ |
 |NULL<-+
 ++

Signed-off-by: John Snow 
---
 blockjob.c   | 35 +--
 qapi/block-core.json |  5 -
 2 files changed, 21 insertions(+), 19 deletions(-)

diff --git a/blockjob.c b/blockjob.c
index 93b0a36306..7b5c4063cf 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -44,24 +44,25 @@ static QemuMutex block_job_mutex;
 
 /* BlockJob State Transition Table */
 bool BlockJobSTT[BLOCK_JOB_STATUS__MAX][BLOCK_JOB_STATUS__MAX] = {
-  /* U, C, R, P, Y, S, X, E */
-/* U: */ [BLOCK_JOB_STATUS_UNDEFINED] = {0, 1, 0, 0, 0, 0, 0, 0},
-/* C: */ [BLOCK_JOB_STATUS_CREATED]   = {0, 0, 1, 0, 0, 0, 0, 0},
-/* R: */ [BLOCK_JOB_STATUS_RUNNING]   = {0, 0, 0, 1, 1, 0, 1, 1},
-/* P: */ [BLOCK_JOB_STATUS_PAUSED]= {0, 0, 1, 0, 0, 0, 0, 0},
-/* Y: */ [BLOCK_JOB_STATUS_READY] = {0, 0, 0, 0, 0, 1, 1, 1},
-/* S: */ [BLOCK_JOB_STATUS_STANDBY]   = {0, 0, 0, 0, 1, 0, 0, 0},
-/* X: */ [BLOCK_JOB_STATUS_ABORTING]  = {0, 0, 0, 0, 0, 0, 0, 1},
-/* E: */ [BLOCK_JOB_STATUS_CONCLUDED] = {0, 0, 0, 0, 0, 0, 0, 0},
+  /* U, C, R, P, Y, S, X, E, N */
+/* U: */ [BLOCK_JOB_STATUS_UNDEFINED] = {0, 1, 0, 0, 0, 0, 0, 0, 0},
+/* C: */ [BLOCK_JOB_STATUS_CREATED]   = {0, 0, 1, 0, 0, 0, 0, 0, 1},
+/* R: */ [BLOCK_JOB_STATUS_RUNNING]   = {0, 0, 0, 1, 1, 0, 1, 1, 0},
+/* P: */ [BLOCK_JOB_STATUS_PAUSED]= {0, 0, 1, 0, 0, 0, 0, 0, 0},
+/* Y: */ [BLOCK_JOB_STATUS_READY] = {0, 0, 0, 0, 0, 1, 1, 1, 0},
+/* S: */ [BLOCK_JOB_STATUS_STANDBY]   = {0, 0, 0, 0, 1, 0, 0, 0, 0},
+/* X: */ [BLOCK_JOB_STATUS_ABORTING]  = {0, 0, 0, 0, 0, 0, 0, 1, 0},
+/* E: */ [BLOCK_JOB_STATUS_CONCLUDED] = {0, 0, 0, 0, 0, 0, 0, 0, 1},
+/* N: */ [BLOCK_JOB_STATUS_NULL]  = {0, 0, 0, 0, 0, 0, 0, 0, 0},
 };
 
 bool BlockJobVerbTable[BLOCK_JOB_VERB__MAX][BLOCK_JOB_STATUS__MAX] = {
-  /* U, C, R, P, Y, S, X, E */
-[BLOCK_JOB_VERB_CANCEL]   = {0, 1, 1, 1, 1, 1, 0, 0},
-[BLOCK_JOB_VERB_PAUSE]= {0, 1, 1, 1, 1, 1, 0, 0},
-[BLOCK_JOB_VERB_RESUME]   = {0, 1, 1, 1, 1, 1, 0, 0},
-[BLOCK_JOB_VERB_SET_SPEED]= {0, 1, 1, 1, 1, 1, 0, 0},
-[BLOCK_JOB_VERB_COMPLETE] = {0, 0, 0, 0, 1, 0, 0, 0},
+  /* U, C, R, P, Y, S, X, E, N */
+[BLOCK_JOB_VERB_CANCEL]   = {0, 1, 1, 1, 1, 1, 0, 0, 0},
+[BLOCK_JOB_VERB_PAUSE]= {0, 1, 1, 1, 1, 1, 0, 0, 0},
+[BLOCK_JOB_VERB_RESUME]   = {0, 1, 1, 1, 1, 1, 0, 0, 0},
+[BLOCK_JOB_VERB_SET_SPEED]= {0, 1, 1, 1, 1, 1, 0, 0, 0},
+[BLOCK_JOB_VERB_COMPLETE] = {0, 0, 0, 0, 1, 0, 0, 0, 0},
 };
 
 static void block_job_state_transition(BlockJob *job, BlockJobStatus s1)
@@ -423,6 +424,7 @@ static void block_job_completed_single(BlockJob *job)
 QLIST_REMOVE(job, txn_list);
 block_job_txn_unref(job->txn);
 block_job_event_concluded(job);
+block_job_state_transition(job, BLOCK_JOB_STATUS_NULL);
 block_job_unref(job);
 }
 
@@ -734,9 +736,6 @@ static void block_job_event_completed(BlockJob *job, const 
char *msg)
 
 static void block_job_event_concluded(BlockJob *job)
 {
-if (block_job_is_internal(job) || !job->manual) {
-return;
-}
 block_job_state_transition(job, BLOCK_JOB_STATUS_CONCLUDED);
 }
 
diff --git a/qapi/block-core.json b/qapi/block-core.json
index aeb9b1937b..578c0c91ca 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1003,11 +1003,14 @@
 # @concluded: The