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, 12 insertions, 0 deletions

diff --git a/include/linux/nfs_iostat.h b/include/linux/nfs_iostat.h
index 1cb9a3fed2b..68b10f5f890 100644
--- a/include/linux/nfs_iostat.h
+++ b/include/linux/nfs_iostat.h
@@ -116,4 +116,16 @@ enum nfs_stat_eventcounters {
         __NFSIOS_COUNTSMAX,
 };
 
+/*
+ * NFS local caching servicing counters
+ */
+enum nfs_stat_fscachecounters {
+        NFSIOS_FSCACHE_PAGES_READ_OK,
+        NFSIOS_FSCACHE_PAGES_READ_FAIL,
+        NFSIOS_FSCACHE_PAGES_WRITTEN_OK,
+        NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL,
+        NFSIOS_FSCACHE_PAGES_UNCACHED,
+        __NFSIOS_FSCACHEMAX,
+};
+
 #endif  /* _LINUX_NFS_IOSTAT */