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

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Message-ID: <50781A58.4060403@canonical.com>
Date:	Fri, 12 Oct 2012 15:25:44 +0200
From:	Maarten Lankhorst <maarten.lankhorst@...onical.com>
To:	"Eric W. Biederman" <ebiederm@...ssion.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"

Op 25-09-12 13:29, Eric W. Biederman schreef:
> 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);
>
>
Are you going to send this in? I don't see a fix for this in linus' kernel yet.

Reported-by: Maarten Lankhorst <maarten.lankhorst@...onical.com>
Tested-by: Maarten Lankhorst <maarten.lankhorst@...onical.com>

~Maarten
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