text-based mount.nfs: sort between permanent and temporary errors

The text-based mount.nfs program must distinguish between different types
of errors returned from the kernel.  Permanent errors, like bad mount
options, should cause an immediate failure.  Temporary errors, such as a
connection timeout, should result in a retry of some type.

Add a function that sorts between the two types of errors.  The list of
permanent errors can be adjusted later if needed.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Neil Brown <neilb@suse.de>

1 files changed, 21 insertions, 0 deletions

diff --git a/utils/mount/stropts.c b/utils/mount/stropts.c
index 13523f8..b6d3a12 100644
--- a/utils/mount/stropts.c
+++ b/utils/mount/stropts.c
@@ -238,6 +238,27 @@ static int set_mandatory_options(const char *type,
 }
 
 /*
+ * Distinguish between permanent and temporary errors.
+ *
+ * Returns 0 if the passed-in error is temporary, thus the
+ * mount system call should be retried; returns one if the
+ * passed-in error is permanent, thus the mount system call
+ * should not be retried.
+ */
+static int is_permanent_error(int error)
+{
+	switch (error) {
+	case EACCES:
+	case ESTALE:
+	case ETIMEDOUT:
+	case ECONNREFUSED:
+		return 0;	/* temporary */
+	default:
+		return 1;	/* permanent */
+	}
+}
+
+/*
  * Reconstruct the mount option string based on a portmapper probe
  * of the server.  Returns one if the server's portmapper returned
  * something we can use, otherwise zero.