GIT: unionfs2-2.6.27.y: cleanup: rewrite long while(1) loop more cleanly

[Erez Zadok]

commit af5a43b9f83f05c89515dc0a7a7c0d4cfe14b2da
Author: Erez_Zadok <ezk at cs.sunysb.edu>
Date:   Wed Mar 28 12:42:37 2007 -0400

    cleanup: rewrite long while(1) loop more cleanly

diff --git a/fs/unionfs/copyup.c b/fs/unionfs/copyup.c
index 747e657..56e1371 100644
--- a/fs/unionfs/copyup.c
+++ b/fs/unionfs/copyup.c
@@ -700,89 +700,81 @@ static struct dentry *create_parents_named(struct inode *dir,
 	sb = dentry->d_sb;
 
 	/*
-	 * This is basically while(child_dentry != dentry).  This loop is
-	 * horrible to follow and should be replaced with cleaner code.
+	 * This code goes between the begin/end labels and basically
+	 * emulates a while(child_dentry != dentry), only cleaner and
+	 * shorter than what would be a much longer while loop.
 	 */
-	while (1) {
-		/* get hidden parent dir in the current branch */
-		hidden_parent_dentry =
-			unionfs_lower_dentry_idx(parent_dentry, bindex);
-		unionfs_unlock_dentry(parent_dentry);
+begin:
+	/* get hidden parent dir in the current branch */
+	hidden_parent_dentry = unionfs_lower_dentry_idx(parent_dentry, bindex);
+	unionfs_unlock_dentry(parent_dentry);
+
+	/* init the values to lookup */
+	childname = child_dentry->d_name.name;
+	childnamelen = child_dentry->d_name.len;
+
+	if (child_dentry != dentry) {
+		/* lookup child in the underlying file system */
+		hidden_dentry = lookup_one_len(childname, hidden_parent_dentry,
+					       childnamelen);
+		if (IS_ERR(hidden_dentry))
+			goto out;
+	} else {
+		/*
+		 * Is the name a whiteout of the child name ?  lookup the
+		 * whiteout child in the underlying file system
+		 */
+		hidden_dentry = lookup_one_len(name, hidden_parent_dentry,
+					       strlen(name));
+		if (IS_ERR(hidden_dentry))
+			goto out;
 
-		/* init the values to lookup */
-		childname = child_dentry->d_name.name;
-		childnamelen = child_dentry->d_name.len;
+		/* Replace the current dentry (if any) with the new one */
+		dput(unionfs_lower_dentry_idx(dentry, bindex));
+		unionfs_set_lower_dentry_idx(dentry, bindex,
+					     hidden_dentry);
 
-		if (child_dentry != dentry) {
-			/* lookup child in the underlying file system */
-			hidden_dentry =
-				lookup_one_len(childname, hidden_parent_dentry,
-					       childnamelen);
-			if (IS_ERR(hidden_dentry))
-				goto out;
-		} else {
+		__cleanup_dentry(dentry, bindex, old_bstart, old_bend);
+		goto out;
+	}
 
-			/*
-			 * is the name a whiteout of the child name ?
-			 * lookup the whiteout child in the underlying file
-			 * system
-			 */
-			hidden_dentry =
-				lookup_one_len(name, hidden_parent_dentry,
-					       strlen(name));
-			if (IS_ERR(hidden_dentry))
-				goto out;
+	if (hidden_dentry->d_inode) {
+		/*
+		 * since this already exists we dput to avoid
+		 * multiple references on the same dentry
+		 */
+		dput(hidden_dentry);
+	} else {
+		struct sioq_args args;
 
-			/*
-			 * Replace the current dentry (if any) with the new
-			 * one.
-			 */
-			dput(unionfs_lower_dentry_idx(dentry, bindex));
-			unionfs_set_lower_dentry_idx(dentry, bindex,
-						     hidden_dentry);
+		/* it's a negative dentry, create a new dir */
+		hidden_parent_dentry = lock_parent(hidden_dentry);
 
-			__cleanup_dentry(dentry, bindex, old_bstart, old_bend);
-			break;
-		}
+		args.mkdir.parent = hidden_parent_dentry->d_inode;
+		args.mkdir.dentry = hidden_dentry;
+		args.mkdir.mode = child_dentry->d_inode->i_mode;
 
-		if (hidden_dentry->d_inode) {
-			/*
-			 * since this already exists we dput to avoid
-			 * multiple references on the same dentry
-			 */
-			dput(hidden_dentry);
-		} else {
-			struct sioq_args args;
-
-			/* its a negative dentry, create a new dir */
-			hidden_parent_dentry = lock_parent(hidden_dentry);
-
-			args.mkdir.parent = hidden_parent_dentry->d_inode;
-			args.mkdir.dentry = hidden_dentry;
-			args.mkdir.mode = child_dentry->d_inode->i_mode;
-
-			run_sioq(__unionfs_mkdir, &args);
-			err = args.err;
-
-			if (!err)
-				err = copyup_permissions(dir->i_sb,
-							 child_dentry,
-							 hidden_dentry);
-			unlock_dir(hidden_parent_dentry);
-			if (err) {
-				dput(hidden_dentry);
-				hidden_dentry = ERR_PTR(err);
-				goto out;
-			}
+		run_sioq(__unionfs_mkdir, &args);
+		err = args.err;
 
+		if (!err)
+			err = copyup_permissions(dir->i_sb, child_dentry,
+						 hidden_dentry);
+		unlock_dir(hidden_parent_dentry);
+		if (err) {
+			dput(hidden_dentry);
+			hidden_dentry = ERR_PTR(err);
+			goto out;
 		}
 
-		__set_inode(child_dentry, hidden_dentry, bindex);
-		__set_dentry(child_dentry, hidden_dentry, bindex);
-
-		parent_dentry = child_dentry;
-		child_dentry = path[--count];
 	}
+
+	__set_inode(child_dentry, hidden_dentry, bindex);
+	__set_dentry(child_dentry, hidden_dentry, bindex);
+
+	parent_dentry = child_dentry;
+	child_dentry = path[--count];
+	goto begin;
 out:
 	kfree(path);
 	return hidden_dentry;