Add support to sacctmgr to modify the SystemComment field for a job.

NEWS

@@ -179,7 +179,7 @@ documents those changes that are of interest to users and administrators.
  -- Add support to ship Include configuration files with configless.
  -- Fix issues with track_script cleanup.
  -- Add new max_token_lifespan limit to AuthAltParameters.
- -- sacctmgr - allow Admins to update AdminComment field on a job.
+ -- sacctmgr - allow Admins to update AdminComment and SystemComment fields.
 * Changes in Slurm 21.08.7
 ==========================

doc/man/man1/sacctmgr.1

@@ -274,8 +274,8 @@ A group of clusters that work together to schedule jobs.
 
 .TP
 \fBjob\fR
-Used to modify specific fields of a job: Derived Exit Code, the AdminComment
-string, the Comment string or WCKey.
+Used to modify specific fields of a job: Derived Exit Code, Comment,
+AdminComment, SystemComment, or WCKey.
 .IP
 
 .TP
@@ -1378,6 +1378,12 @@ Jobs must start at or after this time to be modified in the same format as
 \f3EndTime\fP.
 .IP
 
+.TP
+\fBSystemComment\fR=<\fIsystem_comment\fR>
+Arbitrary descriptive string, usually managed by the BurstBufferPlugin.
+Can only be modified by a Slurm administrator.
+.IP
+
 .TP
 \fBUser\fR=<\fIuser_list\fR>
 Used to specify the jobs of users jobs to alter.
@@ -1389,9 +1395,9 @@ Used to specify the wckeys to alter.
 .IP
 
 .P
-The \fIDerivedExitCode\fP, \fIAdminComment\fP, \fIComment\fP and \fIWCKey\fP
-fields are the only fields of a job record in the database that can be modified
-after job completion.
+The \fIDerivedExitCode\fP, \fIAdminComment\fP, \fIComment\fP,
+\fSystemComment\fP, and \fIWCKey\fP fields are the only fields of a job record
+in the database that can be modified after job completion.
 .IP
 
 .SH "LIST/SHOW JOB FORMAT OPTIONS"

src/sacctmgr/job_functions.c

@@ -196,6 +196,12 @@ static int _set_rec(int *start, int argc, char **argv,
 				xfree(job->admin_comment);
 			job->admin_comment = strip_quotes(argv[i]+end, NULL, 1);
 			set = 1;
+		} else if (!xstrncasecmp(argv[i], "SystemComment",
+					 MAX(command_len, 13))) {
+			if (job->system_comment)
+				xfree(job->system_comment);
+			job->system_comment = strip_quotes(argv[i]+end, NULL, 1);
+			set = 1;
 		} else if (!xstrncasecmp(argv[i], "NewWCKey",
 					 MAX(command_len, 1))) {
 			if (job->wckey)