Re: [PATCH] common/attr: _acl_get_max echo 532 for f2fs

[Eric Biggers <ebiggers@kernel.org>]

On Sun, Jan 30, 2022 at 11:07:17PM +0800, Chao Yu wrote:
> On 2022/1/30 17:28, Sun Ke wrote:
> > Run generic/026 on f2fs, the diff:
> > 
> >      -chacl: cannot set access acl on "largeaclfile": Argument list too long
> >      +Wrong ACL count - 532 != 531
> > 
> > The ACL_MAX_ENTRIES depend on MAX_VALUE_LEN(inode), MAX_VALUE_LEN(inode) I got
> > by printk is 4244, so I think the ACL_MAX_ENTRIES should be
> > (4244 - 20) / 8 + 4 =532.
> > 
> > Signed-off-by: Sun Ke <sunke32@huawei.com>
> 
> FYI:
> 
> https://patchwork.kernel.org/project/fstests/patch/20170428131307.3384-1-chao@kernel.org/
> 
> I've update the patch based on Jaegeuk's comments, however, I forgot to send it to
> mailing list, so could you please check revised one below?
> 
> From 68965c837fd04795064b352589e3f7005e6d75f5 Mon Sep 17 00:00:00 2001
> From: Chao Yu <chao@kernel.org>
> Date: Fri, 28 Apr 2017 20:51:11 +0800
> Subject: [PATCH v2] attr: adbjust acl_max of f2fs
> 
> f2fs has set inline_xattr as a default option, and introduced a new option
> named 'noinline_xattr' for disabling default inline_xattr option. So in
> _acl_get_max we need to check 'noinline_xattr' string in fs option,
> otherwise we may select the wrong max acl number since we always found
> the string 'inline_xattr' in fs option.
> 
> Additionally, f2fs has changed disk layout of xattr block a bit, so will
> contain one more entry in both inline and noinline xattr inode, this patch
> will modify the max acl number to adjust it.
> 
> Signed-off-by: Chao Yu <chao@kernel.org>
> ---
> v2:
> - adjust the config for old kernel as well.
>  common/attr | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/common/attr b/common/attr
> index 35682d7c..6377a936 100644
> --- a/common/attr
> +++ b/common/attr
> @@ -26,11 +26,16 @@ _acl_get_max()
>  		echo 8191
>  		;;
>  	f2fs)
> -		_fs_options $TEST_DEV | grep "inline_xattr" >/dev/null 2>&1
> +		_fs_options $TEST_DEV | grep "noinline_xattr" >/dev/null 2>&1
>  		if [ $? -eq 0 ]; then
> -			echo 531
> +			echo 507
>  		else
> -			echo 506
> +			_fs_options $TEST_DEV | grep "inline_xattr" >/dev/null 2>&1
> +			if [ $? -eq 0 ]; then
> +				echo 532
> +			else
> +				echo 507
> +			fi
>  		fi
>  		;;

Can you add a comment that explains how these numbers were calculated?  They
seem very random.

- Eric