Currently, if writing out a log entry fails, we unlink that log entry from our

internal list of logfiles. So if writev(2) fails for potentially transient
errors like ENOSPC, syslogd requires a restart, even if the filesystem has
purged.

This change allows syslogd to ignore ENOSPC space errors, so that when the
filesystem is cleaned up, syslogd will automatically start logging again
without requiring the reset. This makes syslogd(8) a bit more reliable.

MFC after:	1 week

1 files changed, 12 insertions, 5 deletions

diff --git a/usr.sbin/syslogd/syslogd.c b/usr.sbin/syslogd/syslogd.c
index a41b22c..23e30f8 100644
--- a/usr.sbin/syslogd/syslogd.c
+++ b/usr.sbin/syslogd/syslogd.c
@@ -1227,11 +1227,18 @@ fprintlog(struct filed *f, int flags, const char *msg)
 		v->iov_base = lf;
 		v->iov_len = 1;
 		if (writev(f->f_file, iov, 7) < 0) {
-			int e = errno;
-			(void)close(f->f_file);
-			f->f_type = F_UNUSED;
-			errno = e;
-			logerror(f->f_un.f_fname);
+			/*
+			 * If writev(2) fails for potentially transient errors
+			 * like the * filesystem being full, ignore it.
+			 * Otherwise remove * this logfile from the list.
+			 */
+			if (errno != ENOSPC) {
+				int e = errno;
+				(void)close(f->f_file);
+				f->f_type = F_UNUSED;
+				errno = e;
+				logerror(f->f_un.f_fname);
+			}
 		} else if ((flags & SYNC_FILE) && (f->f_flags & FFLAG_SYNC)) {
 			f->f_flags |= FFLAG_NEEDSYNC;
 			needdofsync = 1;