[Qemu-devel] [PATCH] blockjob: expose error string via query

[John Snow <jsnow@redhat.com>]

When we've reached the concluded state, we need to expose the error
state if applicable. Add the new field.

This should be sufficient for determining if a job completed
successfully or not after concluding; if we want to discriminate
based on how it failed more mechanically, we can always add an
explicit return code enumeration later.

I didn't bother to make it only show up if we are in the concluded
state; I don't think it's necessary.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 blockjob.c           | 2 ++
 qapi/block-core.json | 6 +++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/blockjob.c b/blockjob.c
index 27f957e571..4de48166b2 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -831,6 +831,8 @@ BlockJobInfo *block_job_query(BlockJob *job, Error **errp)
     info->status    = job->status;
     info->auto_finalize = job->auto_finalize;
     info->auto_dismiss  = job->auto_dismiss;
+    info->has_error = job->ret != 0;
+    info->error     = job->ret ? g_strdup(strerror(-job->ret)) : NULL;
     return info;
 }
 
diff --git a/qapi/block-core.json b/qapi/block-core.json
index c50517bff3..7da3bea6bc 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1172,6 +1172,9 @@
 # @auto-dismiss: Job will dismiss itself when CONCLUDED, moving to the NULL
 #                state and disappearing from the query list. (since 2.12)
 #
+# @error: Error information if the job did not complete successfully.
+#         Not set if the job completed successfully. (since 2.12.1)
+#
 # Since: 1.1
 ##
 { 'struct': 'BlockJobInfo',
@@ -1179,7 +1182,8 @@
            'offset': 'int', 'busy': 'bool', 'paused': 'bool', 'speed': 'int',
            'io-status': 'BlockDeviceIoStatus', 'ready': 'bool',
            'status': 'BlockJobStatus',
-           'auto-finalize': 'bool', 'auto-dismiss': 'bool' } }
+           'auto-finalize': 'bool', 'auto-dismiss': 'bool',
+           '*error': 'str' } }
 
 ##
 # @query-block-jobs:
-- 
2.14.3