ovl: fold ovl_copy_up_truncate() into ovl_copy_up()

This removes code duplication.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/overlayfs/copy_up.c

@@ -324,7 +324,7 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
  * is possible that the copy up will lock the old parent.  At that point
  * the file will have already been copied up anyway.
  */
-int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
+static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
 			   struct path *lowerpath, struct kstat *stat)
 {
 	DEFINE_DELAYED_CALL(done);
@@ -378,7 +378,7 @@ int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
 	return err;
 }
 
-int ovl_copy_up(struct dentry *dentry)
+int ovl_copy_up_flags(struct dentry *dentry, int flags)
 {
 	int err = 0;
 	const struct cred *old_cred = ovl_override_creds(dentry->d_sb);
@@ -408,6 +408,9 @@ int ovl_copy_up(struct dentry *dentry)
 
 		ovl_path_lower(next, &lowerpath);
 		err = vfs_getattr(&lowerpath, &stat);
+		/* maybe truncate regular file. this has no effect on dirs */
+		if (flags & O_TRUNC)
+			stat.size = 0;
 		if (!err)
 			err = ovl_copy_up_one(parent, next, &lowerpath, &stat);
 
@@ -418,3 +421,8 @@ int ovl_copy_up(struct dentry *dentry)
 
 	return err;
 }
+
+int ovl_copy_up(struct dentry *dentry)
+{
+	return ovl_copy_up_flags(dentry, 0);
+}

fs/overlayfs/inode.c

@@ -13,34 +13,6 @@
 #include <linux/posix_acl.h>
 #include "overlayfs.h"
 
-static int ovl_copy_up_truncate(struct dentry *dentry)
-{
-	int err;
-	struct dentry *parent;
-	struct kstat stat;
-	struct path lowerpath;
-	const struct cred *old_cred;
-
-	parent = dget_parent(dentry);
-	err = ovl_copy_up(parent);
-	if (err)
-		goto out_dput_parent;
-
-	ovl_path_lower(dentry, &lowerpath);
-
-	old_cred = ovl_override_creds(dentry->d_sb);
-	err = vfs_getattr(&lowerpath, &stat);
-	if (!err) {
-		stat.size = 0;
-		err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat);
-	}
-	revert_creds(old_cred);
-
-out_dput_parent:
-	dput(parent);
-	return err;
-}
-
 int ovl_setattr(struct dentry *dentry, struct iattr *attr)
 {
 	int err;
@@ -281,10 +253,7 @@ int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags)
 	if (ovl_open_need_copy_up(file_flags, type, realpath.dentry)) {
 		err = ovl_want_write(dentry);
 		if (!err) {
-			if (file_flags & O_TRUNC)
-				err = ovl_copy_up_truncate(dentry);
-			else
-				err = ovl_copy_up(dentry);
+			err = ovl_copy_up_flags(dentry, file_flags);
 			ovl_drop_write(dentry);
 		}
 	}

fs/overlayfs/overlayfs.h

@@ -219,7 +219,6 @@ void ovl_cleanup(struct inode *dir, struct dentry *dentry);
 
 /* copy_up.c */
 int ovl_copy_up(struct dentry *dentry);
-int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
-		    struct path *lowerpath, struct kstat *stat);
+int ovl_copy_up_flags(struct dentry *dentry, int flags);
 int ovl_copy_xattr(struct dentry *old, struct dentry *new);
 int ovl_set_attr(struct dentry *upper, struct kstat *stat);