libblkid: check fsync() return code

Since 39f5af2598 libblkid uses
O_NONBLOCK. Now it's more obvious that check fsync() (and close())
return value after write() is always a good idea ...

Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=2074486
Signed-off-by: Karel Zak <kzak@redhat.com>

libblkid/src/probe.c

@@ -1414,7 +1414,8 @@ int blkid_do_wipe(blkid_probe pr, int dryrun)
 			/* wipen on device */
 			if (write_all(fd, buf, len))
 				return -1;
-			fsync(fd);
+			if (fsync(fd) != 0)
+				return -1;
 		} else {
 #ifdef HAVE_LINUX_BLKZONED_H
 			uint64_t zone_mask = ~(pr->zone_size - 1);

misc-utils/wipefs.c

@@ -593,7 +593,9 @@ static int do_wipe(struct wipe_control *ctl)
 	if (need_force)
 		warnx(_("Use the --force option to force erase."));
 
-	fsync(blkid_probe_get_fd(pr));
+	if (fsync(blkid_probe_get_fd(pr)) != 0)
+		err(EXIT_FAILURE, _("%s: cannot flush modified buffers"),
+				ctl->devname);
 
 #ifdef BLKRRPART
 	if (reread && (mode & O_EXCL)) {
@@ -613,7 +615,9 @@ static int do_wipe(struct wipe_control *ctl)
 	}
 #endif
 
-	close(blkid_probe_get_fd(pr));
+	if (close(blkid_probe_get_fd(pr)) != 0)
+		err(EXIT_FAILURE, _("%s: close device failed"), ctl->devname);
+
 	blkid_free_probe(pr);
 	free(backup);
 	return 0;