NFS: add I/O performance counters

Invoke the byte and event counter macros where we want to count bytes and
events.

Clean-up: fix a possible NULL dereference in nfs_lock, and simplify
nfs_file_open.

Test-plan:
fsx and iozone on UP and SMP systems, with and without pre-emption.  Watch
for memory overwrite bugs, and performance loss (significantly more CPU
required per op).

Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index 05eb43fadf8e..ae3ddd24cf8f 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -31,6 +31,8 @@
 
 #include <asm/system.h>
 
+#include "iostat.h"
+
 #define NFSDBG_FACILITY         NFSDBG_PAGECACHE
 
 static int nfs_pagein_one(struct list_head *, struct inode *);
@@ -133,6 +135,8 @@ static int nfs_readpage_sync(struct nfs_open_context *ctx, struct inode *inode,
                 }
                 count -= result;
                 rdata->args.pgbase += result;
+                nfs_add_stats(inode, NFSIOS_SERVERREADBYTES, result);
+
                 /* Note: result == 0 should only happen if we're caching
                  * a write that extends the file and punches a hole.
                  */
@@ -458,8 +462,11 @@ void nfs_readpage_result(struct rpc_task *task, void *calldata)
         dprintk("NFS: %4d nfs_readpage_result, (status %d)\n",
                 task->tk_pid, status);
 
+        nfs_add_stats(data->inode, NFSIOS_SERVERREADBYTES, resp->count);
+
         /* Is this a short read? */
         if (task->tk_status >= 0 && resp->count < argp->count && !resp->eof) {
+                nfs_inc_stats(data->inode, NFSIOS_SHORTREAD);
                 /* Has the server at least made some progress? */
                 if (resp->count != 0) {
                         /* Yes, so retry the read at the end of the data */
@@ -491,6 +498,9 @@ int nfs_readpage(struct file *file, struct page *page)
 
         dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
                 page, PAGE_CACHE_SIZE, page->index);
+        nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
+        nfs_add_stats(inode, NFSIOS_READPAGES, 1);
+
         /*
          * Try to flush any pending writes to the file..
          *
@@ -570,6 +580,7 @@ int nfs_readpages(struct file *filp, struct address_space *mapping,
                         inode->i_sb->s_id,
                         (long long)NFS_FILEID(inode),
                         nr_pages);
+        nfs_inc_stats(inode, NFSIOS_VFSREADPAGES);
 
         if (filp == NULL) {
                 desc.ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
@@ -582,6 +593,7 @@ int nfs_readpages(struct file *filp, struct address_space *mapping,
         if (!list_empty(&head)) {
                 int err = nfs_pagein_list(&head, server->rpages);
                 if (!ret)
+                        nfs_add_stats(inode, NFSIOS_READPAGES, err);
                         ret = err;
         }
         put_nfs_open_context(desc.ctx);