/*
   *  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		"1.1"
  
  /*
   * 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_PNFS_READ,
  	NFSIOS_PNFS_WRITE,
  	__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 */