[v2,3/9] block: don't keep AioContext acquired after drive_backup_prepare()

Message ID 20171206144550.22295-4-stefanha@redhat.com
State New
Headers show
Series
  • blockdev: fix QMP 'transaction' with IOThreads
Related show

Commit Message

Stefan Hajnoczi Dec. 6, 2017, 2:45 p.m.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 blockdev.c | 42 ++++++++++++++++++++++++++++++++++--------
 1 file changed, 34 insertions(+), 8 deletions(-)

Comments

Eric Blake Dec. 7, 2017, 9:27 p.m. | #1
On 12/06/2017 08:45 AM, Stefan Hajnoczi wrote:
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  blockdev.c | 42 ++++++++++++++++++++++++++++++++++--------
>  1 file changed, 34 insertions(+), 8 deletions(-)
> 

> @@ -1867,24 +1867,36 @@ static void drive_backup_prepare(BlkActionState *common, Error **errp)
>          return;
>      }
>  
> -    /* AioContext is released in .clean() */
> -    state->aio_context = bdrv_get_aio_context(bs);
> -    aio_context_acquire(state->aio_context);
> +    aio_context = bdrv_get_aio_context(bs);
> +    aio_context_acquire(aio_context);
> +
> +    /* Paired with .clean() */
>      bdrv_drained_begin(bs);
> +
>      state->bs = bs;
>  
>      state->job = do_drive_backup(backup, common->block_job_txn, &local_err);
>      if (local_err) {
>          error_propagate(errp, local_err);
> -        return;
> +        goto out;
>      }
> +
> +out:
> +    aio_context_release(aio_context);

Looks a bit funny to have a label with a single use that would fall
through to the same location anyways.  But it's fine from the future
maintenance point of view, so no need to change it.

Reviewed-by: Eric Blake <eblake@redhat.com>

Patch

diff --git a/blockdev.c b/blockdev.c
index 3b598f8f0e..5a56a1abf2 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1845,7 +1845,6 @@  static void external_snapshot_clean(BlkActionState *common)
 typedef struct DriveBackupState {
     BlkActionState common;
     BlockDriverState *bs;
-    AioContext *aio_context;
     BlockJob *job;
 } DriveBackupState;
 
@@ -1857,6 +1856,7 @@  static void drive_backup_prepare(BlkActionState *common, Error **errp)
     DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
     BlockDriverState *bs;
     DriveBackup *backup;
+    AioContext *aio_context;
     Error *local_err = NULL;
 
     assert(common->action->type == TRANSACTION_ACTION_KIND_DRIVE_BACKUP);
@@ -1867,24 +1867,36 @@  static void drive_backup_prepare(BlkActionState *common, Error **errp)
         return;
     }
 
-    /* AioContext is released in .clean() */
-    state->aio_context = bdrv_get_aio_context(bs);
-    aio_context_acquire(state->aio_context);
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
+    /* Paired with .clean() */
     bdrv_drained_begin(bs);
+
     state->bs = bs;
 
     state->job = do_drive_backup(backup, common->block_job_txn, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-        return;
+        goto out;
     }
+
+out:
+    aio_context_release(aio_context);
 }
 
 static void drive_backup_commit(BlkActionState *common)
 {
     DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
+    AioContext *aio_context;
+
+    aio_context = bdrv_get_aio_context(state->bs);
+    aio_context_acquire(aio_context);
+
     assert(state->job);
     block_job_start(state->job);
+
+    aio_context_release(aio_context);
 }
 
 static void drive_backup_abort(BlkActionState *common)
@@ -1892,18 +1904,32 @@  static void drive_backup_abort(BlkActionState *common)
     DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
 
     if (state->job) {
+        AioContext *aio_context;
+
+        aio_context = bdrv_get_aio_context(state->bs);
+        aio_context_acquire(aio_context);
+
         block_job_cancel_sync(state->job);
+
+        aio_context_release(aio_context);
     }
 }
 
 static void drive_backup_clean(BlkActionState *common)
 {
     DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
+    AioContext *aio_context;
 
-    if (state->aio_context) {
-        bdrv_drained_end(state->bs);
-        aio_context_release(state->aio_context);
+    if (!state->bs) {
+        return;
     }
+
+    aio_context = bdrv_get_aio_context(state->bs);
+    aio_context_acquire(aio_context);
+
+    bdrv_drained_end(state->bs);
+
+    aio_context_release(aio_context);
 }
 
 typedef struct BlockdevBackupState {