From: Trond Myklebust <Trond.Myklebust@netapp.com>
Date: Wed, 15 Aug 2007 12:15:37 -0400
NFS: Optimise nfs_revalidate_inode()

Instead of serialising calls to nfs_revalidate_inode, we should just be
attempting to ensure that we've updated the attributes.

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

 fs/nfs/inode.c |   88 +++++++++++++-------------------------------------------
 1 files changed, 21 insertions(+), 67 deletions(-)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index e062b8f..082b3dd 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -420,41 +420,6 @@ void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr)
 	}
 }
 
-static int nfs_wait_schedule(void *word)
-{
-	if (signal_pending(current))
-		return -ERESTARTSYS;
-	schedule();
-	return 0;
-}
-
-/*
- * Wait for the inode to get unlocked.
- */
-static int nfs_wait_on_inode(struct inode *inode)
-{
-	struct rpc_clnt	*clnt = NFS_CLIENT(inode);
-	struct nfs_inode *nfsi = NFS_I(inode);
-	sigset_t oldmask;
-	int error;
-
-	rpc_clnt_sigmask(clnt, &oldmask);
-	error = wait_on_bit_lock(&nfsi->flags, NFS_INO_REVALIDATING,
-					nfs_wait_schedule, TASK_INTERRUPTIBLE);
-	rpc_clnt_sigunmask(clnt, &oldmask);
-
-	return error;
-}
-
-static void nfs_wake_up_inode(struct inode *inode)
-{
-	struct nfs_inode *nfsi = NFS_I(inode);
-
-	clear_bit(NFS_INO_REVALIDATING, &nfsi->flags);
-	smp_mb__after_clear_bit();
-	wake_up_bit(&nfsi->flags, NFS_INO_REVALIDATING);
-}
-
 int nfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
 {
 	struct inode *inode = dentry->d_inode;
@@ -673,42 +638,34 @@ __nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
 
 	nfs_inc_stats(inode, NFSIOS_INODEREVALIDATE);
 	lock_kernel();
-	if (is_bad_inode(inode))
- 		goto out_nowait;
-	if (NFS_STALE(inode))
- 		goto out_nowait;
-
-	status = nfs_wait_on_inode(inode);
-	if (status < 0)
-		goto out;
 
-	status = -ESTALE;
 	if (NFS_STALE(inode))
 		goto out;
 
-	status = NFS_PROTO(inode)->getattr(server, NFS_FH(inode), &fattr);
-	if (status != 0) {
-		dfprintk(PAGECACHE, "nfs_revalidate_inode: (%s/%Ld) getattr failed, error=%d\n",
-			 inode->i_sb->s_id,
-			 (long long)NFS_FILEID(inode), status);
-		if (status == -ESTALE) {
-			nfs_zap_caches(inode);
-			if (!S_ISDIR(inode->i_mode))
-				set_bit(NFS_INO_STALE, &NFS_FLAGS(inode));
+	for(;;) {
+		status = NFS_PROTO(inode)->getattr(server, NFS_FH(inode), &fattr);
+		if (status != 0) {
+			dfprintk(PAGECACHE, "nfs_revalidate_inode: (%s/%Ld) getattr failed, error=%d\n",
+					inode->i_sb->s_id,
+					(long long)NFS_FILEID(inode), status);
+			if (status == -ESTALE) {
+				nfs_zap_caches(inode);
+				if (!S_ISDIR(inode->i_mode))
+					set_bit(NFS_INO_STALE, &NFS_FLAGS(inode));
+			}
+			goto out;
 		}
-		goto out;
-	}
 
-	spin_lock(&inode->i_lock);
-	status = nfs_update_inode(inode, &fattr);
-	if (status) {
-		spin_unlock(&inode->i_lock);
-		dfprintk(PAGECACHE, "nfs_revalidate_inode: (%s/%Ld) refresh failed, error=%d\n",
-			 inode->i_sb->s_id,
-			 (long long)NFS_FILEID(inode), status);
-		goto out;
+		status = nfs_refresh_inode(inode, &fattr);
+		if (status) {
+			dfprintk(PAGECACHE, "nfs_revalidate_inode: (%s/%Ld) refresh failed, error=%d\n",
+					inode->i_sb->s_id,
+					(long long)NFS_FILEID(inode), status);
+			break;
+		}
+		if (!(nfsi->cache_validity & NFS_INO_INVALID_ATTR))
+			break;
 	}
-	spin_unlock(&inode->i_lock);
 
 	if (nfsi->cache_validity & NFS_INO_INVALID_ACL)
 		nfs_zap_acl_cache(inode);
@@ -718,9 +675,6 @@ __nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
 		(long long)NFS_FILEID(inode));
 
  out:
-	nfs_wake_up_inode(inode);
-
- out_nowait:
 	unlock_kernel();
 	return status;
 }