vfs: Add inode uid,gid,mode init helper

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 22 insertions, 1 deletions

diff --git a/fs/inode.c b/fs/inode.c
index 498b10f04c3c..2bee20ae3d65 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1606,3 +1606,23 @@ void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
                                   inode->i_ino);
 }
 EXPORT_SYMBOL(init_special_inode);
+
+/**
+ * Init uid,gid,mode for new inode according to posix standards
+ * @inode: New inode
+ * @dir: Directory inode
+ * @mode: mode of the new inode
+ */
+void inode_init_owner(struct inode *inode, const struct inode *dir,
+                        mode_t mode)
+{
+        inode->i_uid = current_fsuid();
+        if (dir && dir->i_mode & S_ISGID) {
+                inode->i_gid = dir->i_gid;
+                if (S_ISDIR(mode))
+                        mode |= S_ISGID;
+        } else
+                inode->i_gid = current_fsgid();
+        inode->i_mode = mode;
+}
+EXPORT_SYMBOL(inode_init_owner);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9626c5fbb0e1..8a733862a411 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1428,7 +1428,8 @@ extern void dentry_unhash(struct dentry *dentry);
  * VFS file helper functions.
  */
 extern int file_permission(struct file *, int);
-
+extern void inode_init_owner(struct inode *inode, const struct inode *dir,
+                        mode_t mode);
 /*
  * VFS FS_IOC_FIEMAP helper definitions.
  */