NFS: Allow concurrent inode revalidation

Currently, if two processes are both trying to revalidate metadata for the
same inode, they will find themselves being serialised. There is no good
justification for this now that we have improved our ability to detect
stale attribute data, so we should remove that serialisation.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 78a5922..ca563ee 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -200,11 +200,10 @@
 /*
  * Bit offsets in flags field
  */
-#define NFS_INO_REVALIDATING	(0)		/* revalidating attrs */
-#define NFS_INO_ADVISE_RDPLUS	(1)		/* advise readdirplus */
-#define NFS_INO_STALE		(2)		/* possible stale inode */
-#define NFS_INO_ACL_LRU_SET	(3)		/* Inode is on the LRU list */
-#define NFS_INO_MOUNTPOINT	(4)		/* inode is remote mountpoint */
+#define NFS_INO_ADVISE_RDPLUS	(0)		/* advise readdirplus */
+#define NFS_INO_STALE		(1)		/* possible stale inode */
+#define NFS_INO_ACL_LRU_SET	(2)		/* Inode is on the LRU list */
+#define NFS_INO_MOUNTPOINT	(3)		/* inode is remote mountpoint */
 
 static inline struct nfs_inode *NFS_I(const struct inode *inode)
 {