job: Add error message for failing jobs

So far we relied on job->ret and strerror() to produce an error message
for failed jobs. Not surprisingly, this tends to result in completely
useless messages.

This adds a Job.error field that can contain an error string for a
failing job, and a parameter to job_completed() that sets the field. As
a default, if NULL is passed, we continue to use strerror(job->ret).

All existing callers are changed to pass NULL. They can be improved in
separate patches.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/block/backup.c b/block/backup.c
index 4e228e959b..5661435675 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -321,7 +321,7 @@ static void backup_complete(Job *job, void *opaque)
 {
     BackupCompleteData *data = opaque;
 
-    job_completed(job, data->ret);
+    job_completed(job, data->ret, NULL);
     g_free(data);
 }