From mboxrd@z Thu Jan  1 00:00:00 1970
From: Al Viro <viro@ZenIV.linux.org.uk>
Subject: Re: [patch 10/24] vfs: truncate: append-only checking cleanup
Date: Thu, 15 May 2008 08:49:52 +0100
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References: <20080506091327.259950960@szeredi.hu> <20080506091418.842237934@szeredi.hu>
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Cc: akpm@linux-foundation.org, hch@infradead.org,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
To: Miklos Szeredi <miklos@szeredi.hu>
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On Tue, May 06, 2008 at 11:13:37AM +0200, Miklos Szeredi wrote:
> -	error = -EPERM;
> -	if (IS_APPEND(inode))
> -		goto mnt_drop_write_and_out;
> -
>  	error = get_write_access(inode);
>  	if (error)
>  		goto mnt_drop_write_and_out;

errno change and worse than that - we
	a) get different errno with append-only file mmaped shared
	b) break_lease() happening, despite the file being append-only

> @@ -321,10 +317,6 @@ static long do_sys_ftruncate(unsigned in
>  	if (small && length > MAX_NON_LFS)
>  		goto out_putf;
>  
> -	error = -EPERM;
> -	if (IS_APPEND(inode))
> -		goto out_putf;
> -
>  	error = locks_verify_truncate(inode, file, length);

Again, errno change...

> @@ -1639,8 +1639,6 @@ int may_open(struct nameidata *nd, int a
>  	if (IS_APPEND(inode)) {
>  		if  ((flag & FMODE_WRITE) && !(flag & O_APPEND))
>  			return -EPERM;
> -		if (flag & O_TRUNC)
> -			return -EPERM;
>  	}

Bogus break_lease() following that...