GIT: unionfs2-2.6.27.y: fs/unionfs/: Don't duplicate the struct nameidata

[Erez Zadok]

commit aee279534cd883048e7eabe4847cfec9b88da6f6
Author: Josef 'Jeff' Sipek <jsipek at cs.sunysb.edu>
Date:   Sun Jan 28 14:20:19 2007 -0500

    fs/unionfs/: Don't duplicate the struct nameidata
    
    The only fields that we have to watch out for are the dentry and vfsmount.
    Additionally, this makes Unionfs gentler on the stack as nameidata is rather
    large.
    
    Signed-off-by: Josef 'Jeff' Sipek <jsipek at cs.sunysb.edu>

diff --git a/fs/unionfs/inode.c b/fs/unionfs/inode.c
index 3b4a388..1b2e8a8 100644
--- a/fs/unionfs/inode.c
+++ b/fs/unionfs/inode.c
@@ -191,15 +191,25 @@ static struct dentry *unionfs_lookup(struct inode *parent,
 				     struct dentry *dentry,
 				     struct nameidata *nd)
 {
-	struct nameidata lowernd; /* TODO: be gentler to the stack */
+	struct path path_save;
+	struct dentry *ret;
 
-	if (nd)
-		memcpy(&lowernd, nd, sizeof(struct nameidata));
-	else
-		memset(&lowernd, 0, sizeof(struct nameidata));
+	/* save the dentry & vfsmnt from namei */
+	if (nd) {
+		path_save.dentry = nd->dentry;
+		path_save.mnt = nd->mnt;
+	}
 
 	/* The locking is done by unionfs_lookup_backend. */
-	return unionfs_lookup_backend(dentry, &lowernd, INTERPOSE_LOOKUP);
+	ret = unionfs_lookup_backend(dentry, nd, INTERPOSE_LOOKUP);
+
+	/* restore the dentry & vfsmnt in namei */
+	if (nd) {
+		nd->dentry = path_save.dentry;
+		nd->mnt = path_save.mnt;
+	}
+
+	return ret;
 }
 
 static int unionfs_link(struct dentry *old_dentry, struct inode *dir,