NFS: Only look at the change attribute cache state in nfs_check_verifier

When looking at whether or not our dcache is valid, we really don't care
about the general state of the directory attribute cache. Instead, we
we only care about the state of the change attribute.

This fixes a performance issue when the client is responsible for
changing the directory contents; a number of NFSv4 operations will
atomically update the directory change attribute, but may not return
all the other attributes.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 6 insertions, 8 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index f5702457c052..7483722162fa 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1030,8 +1030,6 @@ EXPORT_SYMBOL_GPL(nfs_force_lookup_revalidate);
 static int nfs_check_verifier(struct inode *dir, struct dentry *dentry,
 			      int rcu_walk)
 {
-	int ret;
-
 	if (IS_ROOT(dentry))
 		return 1;
 	if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)
@@ -1039,12 +1037,12 @@ static int nfs_check_verifier(struct inode *dir, struct dentry *dentry,
 	if (!nfs_verify_change_attribute(dir, dentry->d_time))
 		return 0;
 	/* Revalidate nfsi->cache_change_attribute before we declare a match */
-	if (rcu_walk)
-		ret = nfs_revalidate_inode_rcu(NFS_SERVER(dir), dir);
-	else
-		ret = nfs_revalidate_inode(NFS_SERVER(dir), dir);
-	if (ret < 0)
-		return 0;
+	if (nfs_mapping_need_revalidate_inode(dir)) {
+		if (rcu_walk)
+			return 0;
+		if (__nfs_revalidate_inode(NFS_SERVER(dir), dir) < 0)
+			return 0;
+	}
 	if (!nfs_verify_change_attribute(dir, dentry->d_time))
 		return 0;
 	return 1;