linux-kernel - Re: [PATCH AUTOSEL 5.1 025/375] orangefs: truncate before updating size

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Date:   Wed, 22 May 2019 17:44:37 -0400
From:   martin@...ibond.com
To:     Sasha Levin <sashal@...nel.org>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Mike Marshall <hubcap@...ibond.com>, devel@...ts.orangefs.org
Subject: Re: [PATCH AUTOSEL 5.1 025/375] orangefs: truncate before updating
 size

I don't think it makes much sense to put this one in stable.  Without
the rest of the pagecache patches the race doesn't exist.

Martin

On Wed, May 22, 2019 at 03:15:25PM -0400, Sasha Levin wrote:
> From: Martin Brandenburg <martin@...ibond.com>
> 
> [ Upstream commit 33713cd09ccdc1e01b10d0782ae60200d4989553 ]
> 
> Otherwise we race with orangefs_writepage/orangefs_writepages
> which and does not expect i_size < page_offset.
> 
> Fixes xfstests generic/129.
> 
> Signed-off-by: Martin Brandenburg <martin@...ibond.com>
> Signed-off-by: Mike Marshall <hubcap@...ibond.com>
> Signed-off-by: Sasha Levin <sashal@...nel.org>
> ---
>  fs/orangefs/inode.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/orangefs/inode.c b/fs/orangefs/inode.c
> index c3334eca18c7e..3260f757c0803 100644
> --- a/fs/orangefs/inode.c
> +++ b/fs/orangefs/inode.c
> @@ -172,7 +172,11 @@ static int orangefs_setattr_size(struct inode *inode, struct iattr *iattr)
>  	}
>  	orig_size = i_size_read(inode);
>  
> -	truncate_setsize(inode, iattr->ia_size);
> +	/* This is truncate_setsize in a different order. */
> +	truncate_pagecache(inode, iattr->ia_size);
> +	i_size_write(inode, iattr->ia_size);
> +	if (iattr->ia_size > orig_size)
> +		pagecache_isize_extended(inode, orig_size, iattr->ia_size);
>  
>  	new_op = op_alloc(ORANGEFS_VFS_OP_TRUNCATE);
>  	if (!new_op)
> -- 
> 2.20.1
>