NFS: Add some new I/O counters for FS-Cache doing things for NFS

Add some new NFS I/O counters for FS-Cache doing things for NFS.  A new line is
emitted into /proc/pid/mountstats if caching is enabled that looks like:

	fsc: <rok> <rfl> <wok> <wfl> <unc>

Where <rok> is the number of pages read successfully from the cache, <rfl> is
the number of failed page reads against the cache, <wok> is the number of
successful page writes to the cache, <wfl> is the number of failed page writes
to the cache, and <unc> is the number of NFS pages that have been disconnected
from the cache.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 87f65ae07f32..b5fea776a0dc 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -642,6 +642,10 @@ static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
                         totals.events[i] += stats->events[i];
                 for (i = 0; i < __NFSIOS_BYTESMAX; i++)
                         totals.bytes[i] += stats->bytes[i];
+#ifdef CONFIG_NFS_FSCACHE
+                for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
+                        totals.fscache[i] += stats->fscache[i];
+#endif
 
                 preempt_enable();
         }
@@ -652,6 +656,13 @@ static int nfs_show_stats(struct seq_file *m, struct vfsmount *mnt)
         seq_printf(m, "\n\tbytes:\t");
         for (i = 0; i < __NFSIOS_BYTESMAX; i++)
                 seq_printf(m, "%Lu ", totals.bytes[i]);
+#ifdef CONFIG_NFS_FSCACHE
+        if (nfss->options & NFS_OPTION_FSCACHE) {
+                seq_printf(m, "\n\tfsc:\t");
+                for (i = 0; i < __NFSIOS_FSCACHEMAX; i++)
+                        seq_printf(m, "%Lu ", totals.bytes[i]);
+        }
+#endif
         seq_printf(m, "\n");
 
         rpc_print_iostats(m, nfss->client);