1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 *  User-space visible declarations for NFS client per-mount
4 *  point statistics
5 *
6 *  Copyright (C) 2005, 2006 Chuck Lever <cel@netapp.com>
7 *
8 *  NFS client per-mount statistics provide information about the
9 *  health of the NFS client and the health of each NFS mount point.
10 *  Generally these are not for detailed problem diagnosis, but
11 *  simply to indicate that there is a problem.
12 *
13 *  These counters are not meant to be human-readable, but are meant
14 *  to be integrated into system monitoring tools such as "sar" and
15 *  "iostat".  As such, the counters are sampled by the tools over
16 *  time, and are never zeroed after a file system is mounted.
17 *  Moving averages can be computed by the tools by taking the
18 *  difference between two instantaneous samples  and dividing that
19 *  by the time between the samples.
20 */
21
22#ifndef _LINUX_NFS_IOSTAT
23#define _LINUX_NFS_IOSTAT
24
25#define NFS_IOSTAT_VERS		"1.1"
26
27/*
28 * NFS byte counters
29 *
30 * 1.  SERVER - the number of payload bytes read from or written
31 *     to the server by the NFS client via an NFS READ or WRITE
32 *     request.
33 *
34 * 2.  NORMAL - the number of bytes read or written by applications
35 *     via the read(2) and write(2) system call interfaces.
36 *
37 * 3.  DIRECT - the number of bytes read or written from files
38 *     opened with the O_DIRECT flag.
39 *
40 * These counters give a view of the data throughput into and out
41 * of the NFS client.  Comparing the number of bytes requested by
42 * an application with the number of bytes the client requests from
43 * the server can provide an indication of client efficiency
44 * (per-op, cache hits, etc).
45 *
46 * These counters can also help characterize which access methods
47 * are in use.  DIRECT by itself shows whether there is any O_DIRECT
48 * traffic.  NORMAL + DIRECT shows how much data is going through
49 * the system call interface.  A large amount of SERVER traffic
50 * without much NORMAL or DIRECT traffic shows that applications
51 * are using mapped files.
52 *
53 * NFS page counters
54 *
55 * These count the number of pages read or written via nfs_readpage(),
56 * nfs_readpages(), or their write equivalents.
57 *
58 * NB: When adding new byte counters, please include the measured
59 * units in the name of each byte counter to help users of this
60 * interface determine what exactly is being counted.
61 */
62enum nfs_stat_bytecounters {
63	NFSIOS_NORMALREADBYTES = 0,
64	NFSIOS_NORMALWRITTENBYTES,
65	NFSIOS_DIRECTREADBYTES,
66	NFSIOS_DIRECTWRITTENBYTES,
67	NFSIOS_SERVERREADBYTES,
68	NFSIOS_SERVERWRITTENBYTES,
69	NFSIOS_READPAGES,
70	NFSIOS_WRITEPAGES,
71	__NFSIOS_BYTESMAX,
72};
73
74/*
75 * NFS event counters
76 *
77 * These counters provide a low-overhead way of monitoring client
78 * activity without enabling NFS trace debugging.  The counters
79 * show the rate at which VFS requests are made, and how often the
80 * client invalidates its data and attribute caches.  This allows
81 * system administrators to monitor such things as how close-to-open
82 * is working, and answer questions such as "why are there so many
83 * GETATTR requests on the wire?"
84 *
85 * They also count anamolous events such as short reads and writes,
86 * silly renames due to close-after-delete, and operations that
87 * change the size of a file (such operations can often be the
88 * source of data corruption if applications aren't using file
89 * locking properly).
90 */
91enum nfs_stat_eventcounters {
92	NFSIOS_INODEREVALIDATE = 0,
93	NFSIOS_DENTRYREVALIDATE,
94	NFSIOS_DATAINVALIDATE,
95	NFSIOS_ATTRINVALIDATE,
96	NFSIOS_VFSOPEN,
97	NFSIOS_VFSLOOKUP,
98	NFSIOS_VFSACCESS,
99	NFSIOS_VFSUPDATEPAGE,
100	NFSIOS_VFSREADPAGE,
101	NFSIOS_VFSREADPAGES,
102	NFSIOS_VFSWRITEPAGE,
103	NFSIOS_VFSWRITEPAGES,
104	NFSIOS_VFSGETDENTS,
105	NFSIOS_VFSSETATTR,
106	NFSIOS_VFSFLUSH,
107	NFSIOS_VFSFSYNC,
108	NFSIOS_VFSLOCK,
109	NFSIOS_VFSRELEASE,
110	NFSIOS_CONGESTIONWAIT,
111	NFSIOS_SETATTRTRUNC,
112	NFSIOS_EXTENDWRITE,
113	NFSIOS_SILLYRENAME,
114	NFSIOS_SHORTREAD,
115	NFSIOS_SHORTWRITE,
116	NFSIOS_DELAY,
117	NFSIOS_PNFS_READ,
118	NFSIOS_PNFS_WRITE,
119	__NFSIOS_COUNTSMAX,
120};
121
122#endif	/* _LINUX_NFS_IOSTAT */
123