From: Erez Zadok <ezk@cs.sunysb.edu>
Date: Sat, 30 Apr 2011 05:33:58 +0000 (-0400)
Subject: VFS: introduce lookup_one_len_nd
X-Git-Url: https://git.fsl.cs.stonybrook.edu/?a=commitdiff_plain;h=311117c07b4183291b9ccb7dea67394fc4e8291f;p=unionfs-3.8.y.git

VFS: introduce lookup_one_len_nd

Just like lookup_one_len() but passes a nameidata parameter, which is now
required by NFS3, else you get an oops.

Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
---

diff --git a/fs/namei.c b/fs/namei.c
index ec97aef5c21..d6f3fb0d619 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2142,6 +2142,42 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
 	return __lookup_hash(&this, base, 0);
 }
 
+/* pass nameidata from caller (useful for NFS) */
+struct dentry *lookup_one_len_nd(const char *name, struct dentry *base,
+				 int len, struct nameidata *nd)
+{
+	struct qstr this;
+	unsigned long hash;
+	unsigned int c;
+
+	WARN_ON_ONCE(!mutex_is_locked(&base->d_inode->i_mutex));
+
+	this.name = name;
+	this.len = len;
+	if (!len)
+		return ERR_PTR(-EACCES);
+
+	hash = init_name_hash();
+	while (len--) {
+		c = *(const unsigned char *)name++;
+		if (c == '/' || c == '\0')
+			return ERR_PTR(-EACCES);
+		hash = partial_name_hash(c, hash);
+	}
+	this.hash = end_name_hash(hash);
+	/*
+	 * See if the low-level filesystem might want
+	 * to use its own hash..
+	 */
+	if (base->d_flags & DCACHE_OP_HASH) {
+		int err = base->d_op->d_hash(base, base->d_inode, &this);
+		if (err < 0)
+			return ERR_PTR(err);
+	}
+
+	return __lookup_hash(&this, base, nd);
+}
+
 int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
 		 struct path *path, int *empty)
 {
@@ -4085,6 +4121,7 @@ EXPORT_SYMBOL(follow_up);
 EXPORT_SYMBOL(get_write_access); /* nfsd */
 EXPORT_SYMBOL(lock_rename);
 EXPORT_SYMBOL(lookup_one_len);
+EXPORT_SYMBOL(lookup_one_len_nd);
 EXPORT_SYMBOL(page_follow_link_light);
 EXPORT_SYMBOL(page_put_link);
 EXPORT_SYMBOL(page_readlink);
diff --git a/include/linux/namei.h b/include/linux/namei.h
index 5a5ff57ceed..0c4c26cbaf6 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -74,6 +74,8 @@ extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
 			   const char *, unsigned int, struct path *);
 
 extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
+extern struct dentry *lookup_one_len_nd(const char *, struct dentry *, int,
+				      struct nameidata *nd);
 
 extern int follow_down_one(struct path *);
 extern int follow_down(struct path *);