Re: [PATCH] xfs: use xfs_vn_setattr_size to check on new size

[Christoph Hellwig <hch@infradead.org>]

On Thu, Dec 01, 2016 at 06:18:00PM +0800, Eryu Guan wrote:
> Commit 6552321831dc ("xfs: remove i_iolock and use i_rwsem in the
> VFS inode instead") introduced a regression that truncate(2) doesn't
> check on new size, so it succeeds even if the new size exceeds the
> current resource limit. Because xfs_setattr_size() was used instead
> of xfs_vn_setattr_size(), and the latter calls xfs_vn_change_ok()
> first to do sanity check on permission and new size.

Oops, looks like this was a merge error..

> 
> This is found by truncate03 test from ltp, and the following is a
> simplified reproducer:
> 
>   #!/bin/bash
>   dev=/dev/sda5
>   mnt=/mnt/xfs
> 
>   mkfs -t xfs -f $dev
>   mount $dev $mnt
> 
>   # set max file size to 16k
>   ulimit -f 16
>   truncate -s $((16 * 1024 + 1)) /mnt/xfs/testfile
>   [ $? -eq 0 ] && echo "FAIL: truncate exceeded max file size"
>   ulimit -f unlimited
>   umount $mnt

Can you add this to xfstests?

The patch looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>