[PATCH 1/5] fs: Introduce vfs_path_lookup

["Josef 'Jeff' Sipek" <jsipek@cs.sunysb.edu>]

Signed-off-by: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu>
---
 fs/namei.c            |   32 ++++++++++++++++++++++++++++++++
 include/linux/namei.h |    2 ++
 2 files changed, 34 insertions(+), 0 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 3449e0a..090cce4 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1175,6 +1175,37 @@ int fastcall path_lookup(const char *name, unsigned int flags,
 	return do_path_lookup(AT_FDCWD, name, flags, nd);
 }
 
+/**
+ * vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair
+ * @dentry:  pointer to dentry of the base directory
+ * @mnt: pointer to vfs mount of the base directory
+ * @name: pointer to file name
+ * @flags: lookup flags
+ * @nd: pointer to nameidata
+ */
+int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
+		    const char *name, unsigned int flags, 
+		    struct nameidata *nd)
+{
+	int retval;
+
+	/* same as do_path_lookup */
+	nd->last_type = LAST_ROOT;
+	nd->flags = flags;
+	nd->depth = 0;
+
+	nd->mnt = mntget(mnt);
+	nd->dentry = dget(dentry);
+
+	retval = path_walk(name, nd);
+	if (unlikely(!retval && !audit_dummy_context() && nd->dentry &&
+				nd->dentry->d_inode))
+		audit_inode(name, nd->dentry->d_inode);
+
+	return retval;
+
+}
+
 static int __path_lookup_intent_open(int dfd, const char *name,
 		unsigned int lookup_flags, struct nameidata *nd,
 		int open_flags, int create_mode)
@@ -2799,6 +2830,7 @@ EXPORT_SYMBOL(__page_symlink);
 EXPORT_SYMBOL(page_symlink);
 EXPORT_SYMBOL(page_symlink_inode_operations);
 EXPORT_SYMBOL(path_lookup);
+EXPORT_SYMBOL(vfs_path_lookup);
 EXPORT_SYMBOL(path_release);
 EXPORT_SYMBOL(path_walk);
 EXPORT_SYMBOL(permission);
diff --git a/include/linux/namei.h b/include/linux/namei.h
index 0ab27ba..4718788 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -70,6 +70,8 @@ extern int FASTCALL(__user_walk_fd(int dfd, const char __user *, unsigned, struc
 #define user_path_walk_link(name,nd) \
 	__user_walk_fd(AT_FDCWD, name, 0, nd)
 extern int FASTCALL(path_lookup(const char *, unsigned, struct nameidata *));
+extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
+			   const char *, unsigned int, struct nameidata *);
 extern int FASTCALL(path_walk(const char *, struct nameidata *));
 extern int FASTCALL(link_path_walk(const char *, struct nameidata *));
 extern void path_release(struct nameidata *);
-- 
1.5.2.rc1.20.g86b9