afs: Fix TTL on VL server and address lists

Currently the TTL on VL server and address lists isn't set in all
circumstances and may be set to poor choices in others, since the TTL is
derived from the SRV/AFSDB DNS record if and when available.

Fix the TTL by limiting the range to a minimum and maximum from the current
time.  At some point these can be made into sysctl knobs.  Further, use the
TTL we obtained from the upcall to set the expiry on negative results too;
in future a mechanism can be added to force reloading of such data.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 11 insertions, 3 deletions

diff --git a/fs/afs/proc.c b/fs/afs/proc.c
index 6585f4bec0d3..fc36c41641ab 100644
--- a/fs/afs/proc.c
+++ b/fs/afs/proc.c
@@ -37,16 +37,24 @@ static inline struct afs_net *afs_seq2net_single(struct seq_file *m)
  */
 static int afs_proc_cells_show(struct seq_file *m, void *v)
 {
-	struct afs_cell *cell = list_entry(v, struct afs_cell, proc_link);
+	struct afs_vlserver_list *vllist;
+	struct afs_cell *cell;
 
 	if (v == SEQ_START_TOKEN) {
 		/* display header on line 1 */
-		seq_puts(m, "USE NAME\n");
+		seq_puts(m, "USE    TTL SV NAME\n");
 		return 0;
 	}
 
+	cell = list_entry(v, struct afs_cell, proc_link);
+	vllist = rcu_dereference(cell->vl_servers);
+
 	/* display one cell per line on subsequent lines */
-	seq_printf(m, "%3u %s\n", atomic_read(&cell->usage), cell->name);
+	seq_printf(m, "%3u %6lld %2u %s\n",
+		   atomic_read(&cell->usage),
+		   cell->dns_expiry - ktime_get_real_seconds(),
+		   vllist ? vllist->nr_servers : 0,
+		   cell->name);
 	return 0;
 }