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, 7 insertions, 0 deletions

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 4e9b3a1b36c5..fc07ce4885da 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -54,6 +54,8 @@
 #include <asm/uaccess.h>
 #include <asm/atomic.h>
 
+#include "iostat.h"
+
 #define NFSDBG_FACILITY         NFSDBG_VFS
 #define MAX_DIRECTIO_SIZE       (4096UL << PAGE_SHIFT)
 
@@ -67,6 +69,7 @@ struct nfs_direct_req {
         struct kref             kref;           /* release manager */
         struct list_head        list;           /* nfs_read_data structs */
         wait_queue_head_t       wait;           /* wait for i/o completion */
+        struct inode *          inode;          /* target file of I/O */
         struct page **          pages;          /* pages in our buffer */
         unsigned int            npages;         /* count of pages */
         atomic_t                complete,       /* i/os we're waiting for */
@@ -357,7 +360,9 @@ static ssize_t nfs_direct_read_seg(struct inode *inode,
 
         dreq->pages = pages;
         dreq->npages = nr_pages;
+        dreq->inode = inode;
 
+        nfs_add_stats(inode, NFSIOS_DIRECTREADBYTES, count);
         rpc_clnt_sigmask(clnt, &oldset);
         nfs_direct_read_schedule(dreq, inode, ctx, user_addr, count,
                                  file_offset);
@@ -572,6 +577,7 @@ static ssize_t nfs_direct_write(struct inode *inode,
                         return page_count;
                 }
 
+                nfs_add_stats(inode, NFSIOS_DIRECTWRITTENBYTES, size);
                 result = nfs_direct_write_seg(inode, ctx, user_addr, size,
                                 file_offset, pages, page_count);
                 nfs_free_user_pages(pages, page_count, 0);
@@ -581,6 +587,7 @@ static ssize_t nfs_direct_write(struct inode *inode,
                                 break;
                         return result;
                 }
+                nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, result);
                 tot_bytes += result;
                 file_offset += result;
                 if (result < size)