linux-kernel - Re: [PATCH] xfs: set inode size after creating symlink

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Message-ID: <20210121195843.GD1793795@bfoster>
Date:   Thu, 21 Jan 2021 14:58:43 -0500
From:   Brian Foster <bfoster@...hat.com>
To:     Jeffrey Mitchell <jeffrey.mitchell@...rlab.io>
Cc:     "Darrick J . Wong" <djwong@...nel.org>, linux-xfs@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] xfs: set inode size after creating symlink

On Thu, Jan 21, 2021 at 09:19:12AM -0600, Jeffrey Mitchell wrote:
> When XFS creates a new symlink, it writes its size to disk but not to the
> VFS inode. This causes i_size_read() to return 0 for that symlink until
> it is re-read from disk, for example when the system is rebooted.
> 
> I found this inconsistency while protecting directories with eCryptFS.
> The command "stat path/to/symlink/in/ecryptfs" will report "Size: 0" if
> the symlink was created after the last reboot on an XFS root.
> 
> Call i_size_write() in xfs_symlink()
> 
> Signed-off-by: Jeffrey Mitchell <jeffrey.mitchell@...rlab.io>
> ---

Reviewed-by: Brian Foster <bfoster@...hat.com>

>  fs/xfs/xfs_symlink.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/fs/xfs/xfs_symlink.c b/fs/xfs/xfs_symlink.c
> index 1f43fd7f3209..c835827ae389 100644
> --- a/fs/xfs/xfs_symlink.c
> +++ b/fs/xfs/xfs_symlink.c
> @@ -300,6 +300,7 @@ xfs_symlink(
>  		}
>  		ASSERT(pathlen == 0);
>  	}
> +	i_size_write(VFS_I(ip), ip->i_d.di_size);
>  
>  	/*
>  	 * Create the directory entry for the symlink.
> -- 
> 2.25.1
>