NFS: Fix a readdir/lookup inefficiency.
Make sure that nfs_readdir_lookup() handles negative dentries correctly.
If d_lookup() returns a negative dentry, then we need to d_drop() that
since readdir shows that it should be positive.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index bd269d2..db29c7f 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1123,8 +1123,14 @@
}
name.hash = full_name_hash(name.name, name.len);
dentry = d_lookup(parent, &name);
- if (dentry != NULL)
- return dentry;
+ if (dentry != NULL) {
+ /* Is this a positive dentry? */
+ if (dentry->d_inode != NULL)
+ return dentry;
+ /* No, so d_drop to allow one to be created */
+ d_drop(dentry);
+ dput(dentry);
+ }
if (!desc->plus || !(entry->fattr->valid & NFS_ATTR_FATTR))
return NULL;
/* Note: caller is already holding the dir->i_mutex! */