ionice: add -t option

This patch allows "tolerant" behavior, i.e. proceeding even if
priority could not be set. This might be of use in case something
(selinux, old kernel, etc.) does not allow the requested scheduling
priority to be set.

This could be to some extend done as follows:

	ionice -c3 command || command

but the downside is that one could not really tell if what failed was
setting priority or command itself, which could result in duplicate
command run.

This patch solves the situation, so that user can do

	ionice -t -c3 command

Addresses-Red-Hat-Bugzilla: #443842
Signed-off-by: Lubomir Kundrak <lkundrak@redhat.com>
Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/schedutils/ionice.c b/schedutils/ionice.c
index 679014af4..f5c02db5e 100644
--- a/schedutils/ionice.c
+++ b/schedutils/ionice.c
@@ -50,16 +50,17 @@ static void usage(void)
 	printf("\t-c\tScheduling class\n");
 	printf("\t\t\t1: realtime, 2: best-effort, 3: idle\n");
 	printf("\t-p\tProcess pid\n");
+	printf("\t-t\tIgnore failures to set priority, run command unconditionally\n");
 	printf("\t-h\tThis help page\n");
 	printf("\nJens Axboe <axboe@suse.de> (C) 2005\n");
 }
 
 int main(int argc, char *argv[])
 {
-	int ioprio = 4, set = 0, ioprio_class = IOPRIO_CLASS_BE;
+	int ioprio = 4, set = 0, tolerant = 0, ioprio_class = IOPRIO_CLASS_BE;
 	int c, pid = 0;
 
-	while ((c = getopt(argc, argv, "+n:c:p:h")) != EOF) {
+	while ((c = getopt(argc, argv, "+n:c:p:th")) != EOF) {
 		switch (c) {
 		case 'n':
 			ioprio = strtol(optarg, NULL, 10);
@@ -72,6 +73,9 @@ int main(int argc, char *argv[])
 		case 'p':
 			pid = strtol(optarg, NULL, 10);
 			break;
+		case 't':
+			tolerant = 1;
+			break;
 		case 'h':
 		default:
 			usage();
@@ -115,8 +119,10 @@ int main(int argc, char *argv[])
 		}
 	} else {
 		if (ioprio_set(IOPRIO_WHO_PROCESS, pid, ioprio | ioprio_class << IOPRIO_CLASS_SHIFT) == -1) {
-			perror("ioprio_set");
-			exit(EXIT_FAILURE);
+			if (!tolerant) {
+				perror("ioprio_set");
+				exit(EXIT_FAILURE);
+			}
 		}
 
 		if (argv[optind]) {