1 files changed, 68 insertions, 22 deletions

diff --git a/fs/open.c b/fs/open.c
index 005ca91a173b..0c55c8e7f837 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -700,10 +700,7 @@ SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
 	return do_fchmodat(AT_FDCWD, filename, mode);
 }
 
-/**
- * setattr_vfsuid - check and set ia_fsuid attribute
- * @kuid: new inode owner
- *
+/*
  * Check whether @kuid is valid and if so generate and set vfsuid_t in
  * ia_vfsuid.
  *
@@ -718,10 +715,7 @@ static inline bool setattr_vfsuid(struct iattr *attr, kuid_t kuid)
 	return true;
 }
 
-/**
- * setattr_vfsgid - check and set ia_fsgid attribute
- * @kgid: new inode owner
- *
+/*
  * Check whether @kgid is valid and if so generate and set vfsgid_t in
  * ia_vfsgid.
  *
@@ -994,7 +988,6 @@ cleanup_file:
  * @file: file pointer
  * @dentry: pointer to dentry
  * @open: open callback
- * @opened: state of open
  *
  * This can be used to finish opening a file passed to i_op->atomic_open().
  *
@@ -1048,7 +1041,6 @@ EXPORT_SYMBOL(file_path);
  * vfs_open - open the file at the given path
  * @path: path to open
  * @file: newly allocated file with f_flag initialized
- * @cred: credentials to use
  */
 int vfs_open(const struct path *path, struct file *file)
 {
@@ -1121,23 +1113,77 @@ struct file *dentry_create(const struct path *path, int flags, umode_t mode,
 }
 EXPORT_SYMBOL(dentry_create);
 
-struct file *open_with_fake_path(const struct path *path, int flags,
+/**
+ * kernel_file_open - open a file for kernel internal use
+ * @path:	path of the file to open
+ * @flags:	open flags
+ * @inode:	the inode
+ * @cred:	credentials for open
+ *
+ * Open a file for use by in-kernel consumers. The file is not accounted
+ * against nr_files and must not be installed into the file descriptor
+ * table.
+ *
+ * Return: Opened file on success, an error pointer on failure.
+ */
+struct file *kernel_file_open(const struct path *path, int flags,
 				struct inode *inode, const struct cred *cred)
 {
-	struct file *f = alloc_empty_file_noaccount(flags, cred);
-	if (!IS_ERR(f)) {
-		int error;
+	struct file *f;
+	int error;
 
-		f->f_path = *path;
-		error = do_dentry_open(f, inode, NULL);
-		if (error) {
-			fput(f);
-			f = ERR_PTR(error);
-		}
+	f = alloc_empty_file_noaccount(flags, cred);
+	if (IS_ERR(f))
+		return f;
+
+	f->f_path = *path;
+	error = do_dentry_open(f, inode, NULL);
+	if (error) {
+		fput(f);
+		f = ERR_PTR(error);
 	}
 	return f;
 }
-EXPORT_SYMBOL(open_with_fake_path);
+EXPORT_SYMBOL_GPL(kernel_file_open);
+
+/**
+ * backing_file_open - open a backing file for kernel internal use
+ * @path:	path of the file to open
+ * @flags:	open flags
+ * @path:	path of the backing file
+ * @cred:	credentials for open
+ *
+ * Open a backing file for a stackable filesystem (e.g., overlayfs).
+ * @path may be on the stackable filesystem and backing inode on the
+ * underlying filesystem. In this case, we want to be able to return
+ * the @real_path of the backing inode. This is done by embedding the
+ * returned file into a container structure that also stores the path of
+ * the backing inode on the underlying filesystem, which can be
+ * retrieved using backing_file_real_path().
+ */
+struct file *backing_file_open(const struct path *path, int flags,
+			       const struct path *real_path,
+			       const struct cred *cred)
+{
+	struct file *f;
+	int error;
+
+	f = alloc_empty_backing_file(flags, cred);
+	if (IS_ERR(f))
+		return f;
+
+	f->f_path = *path;
+	path_get(real_path);
+	*backing_file_real_path(f) = *real_path;
+	error = do_dentry_open(f, d_inode(real_path->dentry), NULL);
+	if (error) {
+		fput(f);
+		f = ERR_PTR(error);
+	}
+
+	return f;
+}
+EXPORT_SYMBOL_GPL(backing_file_open);
 
 #define WILL_CREATE(flags)	(flags & (O_CREAT | __O_TMPFILE))
 #define O_PATH_FLAGS		(O_DIRECTORY | O_NOFOLLOW | O_PATH | O_CLOEXEC)
@@ -1161,7 +1207,7 @@ inline struct open_how build_open_how(int flags, umode_t mode)
 inline int build_open_flags(const struct open_how *how, struct open_flags *op)
 {
 	u64 flags = how->flags;
-	u64 strip = FMODE_NONOTIFY | O_CLOEXEC;
+	u64 strip = __FMODE_NONOTIFY | O_CLOEXEC;
 	int lookup_flags = 0;
 	int acc_mode = ACC_MODE(flags);