atomic_open(): reorder and clean up a bit

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

fs/namei.c

@@ -2827,14 +2827,11 @@ static int atomic_open(struct nameidata *nd, struct dentry *dentry,
 			int open_flag, umode_t mode,
 			int *opened)
 {
+	struct dentry *const DENTRY_NOT_SET = (void *) -1UL;
 	struct inode *dir =  nd->path.dentry->d_inode;
 	int error;
-	int acc_mode;
-	struct dentry *const DENTRY_NOT_SET = (void *) -1UL;
-	bool excl;
 
-	excl = (open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT);
-	if (excl)
+	if (!(~open_flag & (O_EXCL | O_CREAT)))	/* both O_EXCL and O_CREAT */
 		open_flag &= ~O_TRUNC;
 
 	if (nd->flags & LOOKUP_DIRECTORY)
@@ -2845,14 +2842,24 @@ static int atomic_open(struct nameidata *nd, struct dentry *dentry,
 	error = dir->i_op->atomic_open(dir, dentry, file,
 				       open_to_namei_flags(open_flag),
 				       mode, opened);
-	if (error < 0)
-		goto out;
-
-	if (error) {	/* returned 1, that is */
+	if (!error) {
+		/*
+		 * We didn't have the inode before the open, so check open
+		 * permission here.
+		 */
+		int acc_mode = op->acc_mode;
+		if (*opened & FILE_CREATED) {
+			WARN_ON(!(open_flag & O_CREAT));
+			fsnotify_create(dir, dentry);
+			acc_mode = 0;
+		}
+		error = may_open(&file->f_path, acc_mode, open_flag);
+		if (WARN_ON(error > 0))
+			error = -EINVAL;
+	} else if (error > 0) {
 		if (WARN_ON(file->f_path.dentry == DENTRY_NOT_SET)) {
 			error = -EIO;
-			goto out;
-		}
+		} else {
 			if (file->f_path.dentry) {
 				dput(dentry);
 				dentry = file->f_path.dentry;
@@ -2863,21 +2870,7 @@ static int atomic_open(struct nameidata *nd, struct dentry *dentry,
 			path->mnt = nd->path.mnt;
 			return 1;
 		}
-
-	/*
-	 * We didn't have the inode before the open, so check open permission
-	 * here.
-	 */
-	acc_mode = op->acc_mode;
-	if (*opened & FILE_CREATED) {
-		WARN_ON(!(open_flag & O_CREAT));
-		fsnotify_create(dir, dentry);
-		acc_mode = 0;
 	}
-	error = may_open(&file->f_path, acc_mode, open_flag);
-	if (WARN_ON(error > 0))
-		error = -EINVAL;
-out:
 	dput(dentry);
 	return error;
 }