linux-kernel - [PATCH 4/5] DebugFS : file/directory creation error handling, 2.6.19-rc6

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Message-ID: <20061124185009.GD8952@Krystal>
Date:	Fri, 24 Nov 2006 13:50:09 -0500
From:	Mathieu Desnoyers <compudj@...stal.dyndns.org>
To:	Greg KH <greg@...ah.com>
Cc:	ltt-dev@...fik.org, linux-kernel@...r.kernel.org
Subject: [PATCH 4/5] DebugFS : file/directory creation error handling, 2.6.19-rc6

Correct dentry count to handle creation errors.

This patch puts a dput at the file creation instead of the file removal :
lookup_one_len already returns a dentry with reference count of 1. Then, 
the dget() in simple_mknod increments it when the dentry is associated with a
file. In a scenario where simple_create or simple_mkdir returns an error, this
would lead to an unwanted increment of the reference counter, therefore making
file removal impossible.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>

---BEGIN---
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -161,6 +161,7 @@ static int debugfs_create_by_name(const 
 			error = debugfs_mkdir(parent->d_inode, *dentry, mode);
 		else 
 			error = debugfs_create(parent->d_inode, *dentry, mode);
+		dput(*dentry);
 	} else
 		error = PTR_ERR(*dentry);
 	mutex_unlock(&parent->d_inode->i_mutex);
@@ -272,6 +273,7 @@ EXPORT_SYMBOL_GPL(debugfs_create_dir);
 void debugfs_remove(struct dentry *dentry)
 {
 	struct dentry *parent;
+	int ret = 0;
 	
 	if (!dentry)
 		return;
@@ -283,11 +285,15 @@ void debugfs_remove(struct dentry *dentr
 	mutex_lock(&parent->d_inode->i_mutex);
 	if (debugfs_positive(dentry)) {
 		if (dentry->d_inode) {
-			if (S_ISDIR(dentry->d_inode->i_mode))
-				simple_rmdir(parent->d_inode, dentry);
-			else
+			if (S_ISDIR(dentry->d_inode->i_mode)) {
+				ret = simple_rmdir(parent->d_inode, dentry);
+				if (ret)
+					printk(KERN_ERR
+						"DebugFS rmdir on %s failed : "
+						"directory not empty.\n",
+						dentry->d_name.name);
+			} else
 				simple_unlink(parent->d_inode, dentry);
-		dput(dentry);
 		}
 	}
 	mutex_unlock(&parent->d_inode->i_mutex);
---END---

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