NFS: Move fs/nfs/iostat.h to include/linux

The fs/nfs/iostat.h header has definitions that were designed to be exposed
to user space.  Move these definitions under include/linux so user space can
use the definitions in applications that read /proc/self/mountstats.

Also address a handful of coding style issues called out by checkpatch.pl in
fs/nfs/iostat.h.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 119 insertions, 0 deletions

diff --git a/include/linux/nfs_iostat.h b/include/linux/nfs_iostat.h
new file mode 100644
index 00000000000..1cb9a3fed2b
--- /dev/null
+++ b/include/linux/nfs_iostat.h
@@ -0,0 +1,119 @@
+/*
+ *  User-space visible declarations for NFS client per-mount
+ *  point statistics
+ *
+ *  Copyright (C) 2005, 2006 Chuck Lever <cel@netapp.com>
+ *
+ *  NFS client per-mount statistics provide information about the
+ *  health of the NFS client and the health of each NFS mount point.
+ *  Generally these are not for detailed problem diagnosis, but
+ *  simply to indicate that there is a problem.
+ *
+ *  These counters are not meant to be human-readable, but are meant
+ *  to be integrated into system monitoring tools such as "sar" and
+ *  "iostat".  As such, the counters are sampled by the tools over
+ *  time, and are never zeroed after a file system is mounted.
+ *  Moving averages can be computed by the tools by taking the
+ *  difference between two instantaneous samples  and dividing that
+ *  by the time between the samples.
+ */
+
+#ifndef _LINUX_NFS_IOSTAT
+#define _LINUX_NFS_IOSTAT
+
+#define NFS_IOSTAT_VERS		"1.0"
+
+/*
+ * NFS byte counters
+ *
+ * 1.  SERVER - the number of payload bytes read from or written
+ *     to the server by the NFS client via an NFS READ or WRITE
+ *     request.
+ *
+ * 2.  NORMAL - the number of bytes read or written by applications
+ *     via the read(2) and write(2) system call interfaces.
+ *
+ * 3.  DIRECT - the number of bytes read or written from files
+ *     opened with the O_DIRECT flag.
+ *
+ * These counters give a view of the data throughput into and out
+ * of the NFS client.  Comparing the number of bytes requested by
+ * an application with the number of bytes the client requests from
+ * the server can provide an indication of client efficiency
+ * (per-op, cache hits, etc).
+ *
+ * These counters can also help characterize which access methods
+ * are in use.  DIRECT by itself shows whether there is any O_DIRECT
+ * traffic.  NORMAL + DIRECT shows how much data is going through
+ * the system call interface.  A large amount of SERVER traffic
+ * without much NORMAL or DIRECT traffic shows that applications
+ * are using mapped files.
+ *
+ * NFS page counters
+ *
+ * These count the number of pages read or written via nfs_readpage(),
+ * nfs_readpages(), or their write equivalents.
+ *
+ * NB: When adding new byte counters, please include the measured
+ * units in the name of each byte counter to help users of this
+ * interface determine what exactly is being counted.
+ */
+enum nfs_stat_bytecounters {
+	NFSIOS_NORMALREADBYTES = 0,
+	NFSIOS_NORMALWRITTENBYTES,
+	NFSIOS_DIRECTREADBYTES,
+	NFSIOS_DIRECTWRITTENBYTES,
+	NFSIOS_SERVERREADBYTES,
+	NFSIOS_SERVERWRITTENBYTES,
+	NFSIOS_READPAGES,
+	NFSIOS_WRITEPAGES,
+	__NFSIOS_BYTESMAX,
+};
+
+/*
+ * NFS event counters
+ *
+ * These counters provide a low-overhead way of monitoring client
+ * activity without enabling NFS trace debugging.  The counters
+ * show the rate at which VFS requests are made, and how often the
+ * client invalidates its data and attribute caches.  This allows
+ * system administrators to monitor such things as how close-to-open
+ * is working, and answer questions such as "why are there so many
+ * GETATTR requests on the wire?"
+ *
+ * They also count anamolous events such as short reads and writes,
+ * silly renames due to close-after-delete, and operations that
+ * change the size of a file (such operations can often be the
+ * source of data corruption if applications aren't using file
+ * locking properly).
+ */
+enum nfs_stat_eventcounters {
+	NFSIOS_INODEREVALIDATE = 0,
+	NFSIOS_DENTRYREVALIDATE,
+	NFSIOS_DATAINVALIDATE,
+	NFSIOS_ATTRINVALIDATE,
+	NFSIOS_VFSOPEN,
+	NFSIOS_VFSLOOKUP,
+	NFSIOS_VFSACCESS,
+	NFSIOS_VFSUPDATEPAGE,
+	NFSIOS_VFSREADPAGE,
+	NFSIOS_VFSREADPAGES,
+	NFSIOS_VFSWRITEPAGE,
+	NFSIOS_VFSWRITEPAGES,
+	NFSIOS_VFSGETDENTS,
+	NFSIOS_VFSSETATTR,
+	NFSIOS_VFSFLUSH,
+	NFSIOS_VFSFSYNC,
+	NFSIOS_VFSLOCK,
+	NFSIOS_VFSRELEASE,
+	NFSIOS_CONGESTIONWAIT,
+	NFSIOS_SETATTRTRUNC,
+	NFSIOS_EXTENDWRITE,
+	NFSIOS_SILLYRENAME,
+	NFSIOS_SHORTREAD,
+	NFSIOS_SHORTWRITE,
+	NFSIOS_DELAY,
+	__NFSIOS_COUNTSMAX,
+};
+
+#endif	/* _LINUX_NFS_IOSTAT */