From: Joel Becker <jlbec@evilplan.org>
Date: Tue, 22 Feb 2011 09:09:49 +0000 (-0800)
Subject: configfs: Don't try to d_delete() negative dentries.
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=df7f99670a4c76f269ae57ce91876b309417a316;p=openwrt%2Fstaging%2Fblogic.git

configfs: Don't try to d_delete() negative dentries.

When configfs is faking mkdir() on its subsystem or default group
objects, it starts by adding a negative dentry.  It then tries to
instantiate the group.  If that should fail, it must clean up after
itself.

I was using d_delete() here, but configfs_attach_group() promises to
return an empty dentry on error.  d_delete() explodes with the entry
dentry.  Let's try d_drop() instead.  The unhashing is what we want for
our dentry.

Signed-off-by: Joel Becker <jlbec@evilplan.org>
---

diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index 3313dd19f543..b11d7342eef2 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -689,7 +689,8 @@ static int create_default_group(struct config_group *parent_group,
 			sd = child->d_fsdata;
 			sd->s_type |= CONFIGFS_USET_DEFAULT;
 		} else {
-			d_delete(child);
+			BUG_ON(child->d_inode);
+			d_drop(child);
 			dput(child);
 		}
 	}
@@ -1683,7 +1684,8 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys)
 		err = configfs_attach_group(sd->s_element, &group->cg_item,
 					    dentry);
 		if (err) {
-			d_delete(dentry);
+			BUG_ON(dentry->d_inode);
+			d_drop(dentry);
 			dput(dentry);
 		} else {
 			spin_lock(&configfs_dirent_lock);