From 761731b1805f6ef64eb615e5b82a0801db3cde78 Mon Sep 17 00:00:00 2001
From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Tue, 21 Oct 2014 12:03:56 +0100
Subject: block: let backup blockjob run in BDS AioContext

The backup block job must run in the BlockDriverState AioContext so that
it works with dataplane.

The basics of acquiring the AioContext are easy in blockdev.c.

The completion code in block/backup.c must call bdrv_unref() from the
main loop.  Use block_job_defer_to_main_loop() to achieve that.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 1413889440-32577-8-git-send-email-stefanha@redhat.com
---
 blockdev.c | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

(limited to 'blockdev.c')

diff --git a/blockdev.c b/blockdev.c
index 774051b..9c68988 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2108,6 +2108,7 @@ void qmp_drive_backup(const char *device, const char *target,
     BlockDriverState *bs;
     BlockDriverState *target_bs;
     BlockDriverState *source = NULL;
+    AioContext *aio_context;
     BlockDriver *drv = NULL;
     Error *local_err = NULL;
     int flags;
@@ -2133,9 +2134,12 @@ void qmp_drive_backup(const char *device, const char *target,
         return;
     }
 
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
     if (!bdrv_is_inserted(bs)) {
         error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
-        return;
+        goto out;
     }
 
     if (!has_format) {
@@ -2145,12 +2149,12 @@ void qmp_drive_backup(const char *device, const char *target,
         drv = bdrv_find_format(format);
         if (!drv) {
             error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
-            return;
+            goto out;
         }
     }
 
     if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
-        return;
+        goto out;
     }
 
     flags = bs->open_flags | BDRV_O_RDWR;
@@ -2170,7 +2174,7 @@ void qmp_drive_backup(const char *device, const char *target,
     size = bdrv_getlength(bs);
     if (size < 0) {
         error_setg_errno(errp, -size, "bdrv_getlength failed");
-        return;
+        goto out;
     }
 
     if (mode != NEW_IMAGE_MODE_EXISTING) {
@@ -2187,23 +2191,28 @@ void qmp_drive_backup(const char *device, const char *target,
 
     if (local_err) {
         error_propagate(errp, local_err);
-        return;
+        goto out;
     }
 
     target_bs = NULL;
     ret = bdrv_open(&target_bs, target, NULL, NULL, flags, drv, &local_err);
     if (ret < 0) {
         error_propagate(errp, local_err);
-        return;
+        goto out;
     }
 
+    bdrv_set_aio_context(target_bs, aio_context);
+
     backup_start(bs, target_bs, speed, sync, on_source_error, on_target_error,
                  block_job_cb, bs, &local_err);
     if (local_err != NULL) {
         bdrv_unref(target_bs);
         error_propagate(errp, local_err);
-        return;
+        goto out;
     }
+
+out:
+    aio_context_release(aio_context);
 }
 
 BlockDeviceInfoList *qmp_query_named_block_nodes(Error **errp)
-- 
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