aufs: atomic_open 3/5, pass h_file to au_do_open()

Extend do_open_dir(), au_do_open_nondir() and au_do_open() to receive an
additional parameter h_file, which is an opened file object by branch
fs's ->atomic_open(). By this design/commit, aufs doesn't have to
duplicate many codes into a new aufs_atomic_open() (in later commit),
and can simply share them.
Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>

fs/aufs/f_op.c

@@ -13,11 +13,10 @@
 #include <linux/security.h>
 #include "aufs.h"
 
-int au_do_open_nondir(struct file *file, int flags)
+int au_do_open_nondir(struct file *file, int flags, struct file *h_file)
 {
 	int err;
 	aufs_bindex_t bindex;
-	struct file *h_file;
 	struct dentry *dentry;
 	struct au_finfo *finfo;
 	struct inode *h_inode;
@@ -26,11 +25,15 @@ int au_do_open_nondir(struct file *file, int flags)
 
 	err = 0;
 	dentry = file->f_path.dentry;
+	AuDebugOn(IS_ERR_OR_NULL(dentry));
 	finfo = au_fi(file);
 	memset(&finfo->fi_htop, 0, sizeof(finfo->fi_htop));
 	atomic_set(&finfo->fi_mmapped, 0);
 	bindex = au_dbtop(dentry);
+	if (!h_file)
 		h_file = au_h_open(dentry, bindex, flags, file);
+	else
+		get_file(h_file);
 	if (IS_ERR(h_file))
 		err = PTR_ERR(h_file);
 	else {

fs/aufs/file.c

@@ -84,21 +84,41 @@ out:
 
 int au_do_open(struct file *file, struct au_do_open_args *args)
 {
-	int err;
+	int err, aopen = args->aopen;
 	struct dentry *dentry;
 	struct au_finfo *finfo;
 
+	if (!aopen)
+		err = au_finfo_init(file, args->fidir);
+	else {
+		lockdep_off();
 		err = au_finfo_init(file, args->fidir);
+		lockdep_on();
+	}
 	if (unlikely(err))
 		goto out;
 
 	dentry = file->f_path.dentry;
+	AuDebugOn(IS_ERR_OR_NULL(dentry));
 	di_read_lock_child(dentry, AuLock_IR);
-	err = args->open(file, vfsub_file_flags(file));
+	if (!aopen)
+		err = args->open(file, vfsub_file_flags(file), NULL);
+	else {
+		lockdep_off();
+			err = args->open(file, vfsub_file_flags(file),
+					 args->h_file);
+		lockdep_on();
+	}
 	di_read_unlock(dentry, AuLock_IR);
 
 	finfo = au_fi(file);
+	if (!aopen)
+		fi_write_unlock(file);
+	else {
+		lockdep_off();
 		fi_write_unlock(file);
+		lockdep_on();
+	}
 	if (unlikely(err)) {
 		finfo->fi_hdir = NULL;
 		au_finfo_fin(file);

fs/aufs/file.h

@@ -60,9 +60,11 @@ unsigned int au_file_roflags(unsigned int flags);
 struct file *au_h_open(struct dentry *dentry, aufs_bindex_t bindex, int flags,
 		       struct file *file);
 struct au_do_open_args {
-	int		(*open)(struct file *file, int flags);
+	int		aopen;
+	int		(*open)(struct file *file, int flags,
+				struct file *h_file);
 	struct au_fidir	*fidir;
-	/* add more later */
+	struct file	*h_file;
 };
 int au_do_open(struct file *file, struct au_do_open_args *args);
 int au_reopen_nondir(struct file *file);
@@ -75,7 +77,7 @@ int au_do_flush(struct file *file, fl_owner_t id,
 
 /* f_op.c */
 extern const struct file_operations aufs_file_fop;
-int au_do_open_nondir(struct file *file, int flags);
+int au_do_open_nondir(struct file *file, int flags, struct file *h_file);
 int aufs_release_nondir(struct inode *inode __maybe_unused, struct file *file);
 struct file *au_read_pre(struct file *file, int keep_fi, unsigned int lsc);