linux-kernel - Re: [PATCH] Revert "__d_unalias() should refuse to move mountpoints"

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Message-ID: <87sja6nxvt.fsf@xmission.com>
Date:	Tue, 25 Sep 2012 04:29:58 -0700
From:	ebiederm@...ssion.com (Eric W. Biederman)
To:	Maarten Lankhorst <maarten.lankhorst@...onical.com>
Cc:	al viro <viro@...iv.linux.org.uk>, linux-fsdevel@...r.kernel.org,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] Revert "__d_unalias() should refuse to move mountpoints"

Maarten Lankhorst <maarten.lankhorst@...onical.com> writes:

>> Could you try the following patch?  This should report what directories
>> cannot be renamed because one of them is a mount point and it gives some
>> real insight into what is going on.
>
> ls /
> __d_unalias: /dev -> /dev
> __d_unalias: /proc -> /proc
> __d_unalias: /sys -> /sys

Ok.  That is what I thought was going on.  For some reason nfs is
attempting to recreate an existing dentry.

Does this fix the nfs problem for you?

Eric

diff --git a/fs/dcache.c b/fs/dcache.c
index 8086636..6390f0f 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2404,6 +2404,9 @@ out_unalias:
 	if (likely(!d_mountpoint(alias))) {
 		__d_move(alias, dentry);
 		ret = alias;
+	} else if ((alias->d_parent == dentry->d_parent) &&
+		   !dentry_cmp(alias, dentry->d_name.name, dentry->d_name.len))
+		ret = alias;
 	}
 out_err:
 	spin_unlock(&inode->i_lock);


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