linux-kernel - Re: [PATCH 1/5] ext2: cache NULL when both default

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Date:   Wed, 29 Aug 2018 15:18:15 +0200
From:   Jan Kara <jack@...e.cz>
To:     Chengguang Xu <cgxu519@....com>
Cc:     jack@...e.com, tytso@....edu, adilger.kernel@...ger.ca,
        jaegeuk@...nel.org, yuchao0@...wei.com, shaggy@...nel.org,
        hubcap@...ibond.com, martin@...ibond.com, devel@...ts.orangefs.org,
        linux-kernel@...r.kernel.org, linux-ext4@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net,
        jfs-discussion@...ts.sourceforge.net
Subject: Re: [PATCH 1/5] ext2: cache NULL when both default_acl and acl are
 NULL

On Tue 14-08-18 22:16:30, Chengguang Xu wrote:
> default_acl and acl of newly created inode will be initiated
> as ACL_NOT_CACHED in vfs function inode_init_always() and later
> will be updated by calling xxx_init_acl() in specific filesystems.
> Howerver, when default_acl and acl are NULL then they keep the value
> of ACL_NOT_CACHED, this patch tries to cache NULL for acl/default_acl
> in this case.
> 
> Signed-off-by: Chengguang Xu <cgxu519@....com>
> ---
>  fs/ext2/acl.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/fs/ext2/acl.c b/fs/ext2/acl.c
> index 224c04abb2e5..74411e8ea507 100644
> --- a/fs/ext2/acl.c
> +++ b/fs/ext2/acl.c
> @@ -262,5 +262,8 @@ ext2_init_acl(struct inode *inode, struct inode *dir)
>  			error = __ext2_set_acl(inode, acl, ACL_TYPE_ACCESS);
>  		posix_acl_release(acl);
>  	}
> +	if (!default_acl && !acl)
> +		cache_no_acl(inode);
> +

Thanks for the patch. I'd somewhat prefer something equivalent to:

	if (!acl)
		inode->i_acl = NULL;
	if (!default_acl)
		inode->i_default_acl = NULL;

given the code in ext2_init_acl(). It would be most natural like:

	if (default_acl) {
		do foo
	} else {
		inode->i_default_acl = NULL;
	}

And similarly for 'acl'.

								Honza
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR