NFS: Add event tracing for generic NFS events

Add tracepoints for inode attribute updates, attribute revalidation,
writeback start/end fsync start/end, attribute change start/end,
permission check start/end.

The intention is to enable performance tracing using 'perf'as well as
improving debugging.

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

1 files changed, 11 insertions, 5 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 5d737bd52288..be3da6fe3ad4 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -43,6 +43,8 @@
 #include "internal.h"
 #include "fscache.h"
 
+#include "nfstrace.h"
+
 /* #define NFS_DEBUG_VERBOSE 1 */
 
 static int nfs_opendir(struct inode *, struct file *);
@@ -2178,9 +2180,11 @@ static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask)
         struct nfs_access_entry cache;
         int status;
 
+        trace_nfs_access_enter(inode);
+
         status = nfs_access_get_cached(inode, cred, &cache);
         if (status == 0)
-                goto out;
+                goto out_cached;
 
         /* Be clever: ask server to check for all possible rights */
         cache.mask = MAY_EXEC | MAY_WRITE | MAY_READ;
@@ -2193,13 +2197,15 @@ static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask)
                         if (!S_ISDIR(inode->i_mode))
                                 set_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
                 }
-                return status;
+                goto out;
         }
         nfs_access_add_cache(inode, &cache);
+out_cached:
+        if ((mask & ~cache.mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) != 0)
+                status = -EACCES;
 out:
-        if ((mask & ~cache.mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0)
-                return 0;
-        return -EACCES;
+        trace_nfs_access_exit(inode, status);
+        return status;
 }
 
 static int nfs_open_permission_mask(int openflags)