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, 18 insertions, 0 deletions

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 92ecf24455c..e7c8361cf20 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -63,6 +63,7 @@
 #include <linux/smp_lock.h>
 
 #include "delegation.h"
+#include "iostat.h"
 
 #define NFSDBG_FACILITY         NFSDBG_PAGECACHE
 
@@ -134,6 +135,7 @@ static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int c
         end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count);
         if (i_size >= end)
                 return;
+        nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
         i_size_write(inode, end);
 }
 
@@ -223,6 +225,7 @@ static int nfs_writepage_sync(struct nfs_open_context *ctx, struct inode *inode,
                 wdata->args.pgbase += result;
                 written += result;
                 count -= result;
+                nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, result);
         } while (count);
         /* Update file length */
         nfs_grow_file(page, offset, written);
@@ -279,6 +282,9 @@ int nfs_writepage(struct page *page, struct writeback_control *wbc)
         int priority = wb_priority(wbc);
         int err;
 
+        nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
+        nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
+
         /*
          * Note: We need to ensure that we have a reference to the inode
          *       if we are to do asynchronous writes. If not, waiting
@@ -343,6 +349,8 @@ int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
         struct inode *inode = mapping->host;
         int err;
 
+        nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
+
         err = generic_writepages(mapping, wbc);
         if (err)
                 return err;
@@ -354,6 +362,7 @@ int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
         err = nfs_flush_inode(inode, 0, 0, wb_priority(wbc));
         if (err < 0)
                 goto out;
+        nfs_add_stats(inode, NFSIOS_WRITEPAGES, err);
         wbc->nr_to_write -= err;
         if (!wbc->nonblocking && wbc->sync_mode == WB_SYNC_ALL) {
                 err = nfs_wait_on_requests(inode, 0, 0);
@@ -596,6 +605,9 @@ static int nfs_wait_on_write_congestion(struct address_space *mapping, int intr)
 
         if (!bdi_write_congested(bdi))
                 return 0;
+
+        nfs_inc_stats(mapping->host, NFSIOS_CONGESTIONWAIT);
+
         if (intr) {
                 struct rpc_clnt *clnt = NFS_CLIENT(mapping->host);
                 sigset_t oldset;
@@ -749,6 +761,8 @@ int nfs_updatepage(struct file *file, struct page *page,
         struct nfs_page *req;
         int             status = 0;
 
+        nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
+
         dprintk("NFS:      nfs_updatepage(%s/%s %d@%Ld)\n",
                 file->f_dentry->d_parent->d_name.name,
                 file->f_dentry->d_name.name, count,
@@ -1152,6 +1166,8 @@ void nfs_writeback_done(struct rpc_task *task, void *calldata)
         dprintk("NFS: %4d nfs_writeback_done (status %d)\n",
                 task->tk_pid, task->tk_status);
 
+        nfs_add_stats(data->inode, NFSIOS_SERVERWRITTENBYTES, resp->count);
+
 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
         if (resp->verf->committed < argp->stable && task->tk_status >= 0) {
                 /* We tried a write call, but the server did not
@@ -1177,6 +1193,8 @@ void nfs_writeback_done(struct rpc_task *task, void *calldata)
         if (task->tk_status >= 0 && resp->count < argp->count) {
                 static unsigned long    complain;
 
+                nfs_inc_stats(data->inode, NFSIOS_SHORTWRITE);
+
                 /* Has the server at least made some progress? */
                 if (resp->count != 0) {
                         /* Was this an NFSv2 write or an NFSv3 stable write? */