Re: [PATCH v23 10/22] posix_acl: Improve xattr fixup code

From: Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Andreas Gruenbacher
	<agruenba-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Alexander Viro
	<viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
Cc: Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
	Theodore Ts'o <tytso-3s7WtUTddSA@public.gmane.org>,
	Andreas Dilger
	<adilger.kernel-m1MBpc4rdrD3fQ9qLvQP4Q@public.gmane.org>,
	"J. Bruce Fields"
	<bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>,
	Trond Myklebust
	<trond.myklebust-7I+n7zu2hftEKMMhf/gKZA@public.gmane.org>,
	Anna Schumaker
	<anna.schumaker-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org>,
	Dave Chinner <david-FqsqvQoI3Ljby3iVrkZq2A@public.gmane.org>,
	linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	xfs-VZNHf3L845pBDgjK7y7TUQ@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH v23 10/22] posix_acl: Improve xattr fixup code
Date: Tue, 05 Jul 2016 11:38:50 -0400	[thread overview]
Message-ID: <1467733130.3800.36.camel@redhat.com> (raw)
In-Reply-To: <1467294433-3222-11-git-send-email-agruenba-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

On Thu, 2016-06-30 at 15:47 +0200, Andreas Gruenbacher wrote:
> Both XATTR_NAME_POSIX_ACL_ACCESS and XATTR_NAME_POSIX_ACL_DEFAULT have
> the same XATTR_SYSTEM_PREFIX prefix; don't check for the same prefix
> repeatedly.
> 
> Signed-off-by: Andreas Gruenbacher <agruenba-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> Reviewed-by: Steve French <steve.french-7I+n7zu2hftEKMMhf/gKZA@public.gmane.org>
> ---
>  fs/xattr.c | 29 +++++++++++++++++++++++------
>  1 file changed, 23 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/xattr.c b/fs/xattr.c
> index 4beafc4..61ac218 100644
> --- a/fs/xattr.c
> +++ b/fs/xattr.c
> @@ -295,6 +295,16 @@ out:
>  }
>  EXPORT_SYMBOL_GPL(vfs_removexattr);
>  
> +static void
> +fix_xattr_from_user(const char *kname, void *kvalue, size_t size)
> +{
> +	if (strncmp(kname, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
> +		return;
> +	kname += XATTR_SYSTEM_PREFIX_LEN;
> +	if (!strcmp(kname, XATTR_POSIX_ACL_ACCESS) ||
> +	    !strcmp(kname, XATTR_POSIX_ACL_DEFAULT))
> +		posix_acl_fix_xattr_from_user(kvalue, size);
> +}
>  
>  /*
>   * Extended attribute SET operations
> @@ -329,9 +339,7 @@ setxattr(struct dentry *d, const char __user *name, const void __user *value,
>  			error = -EFAULT;
>  			goto out;
>  		}
> -		if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
> -		    (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
> -			posix_acl_fix_xattr_from_user(kvalue, size);
> +		fix_xattr_from_user(kname, kvalue, size);
>  	}
>  
>  	error = vfs_setxattr(d, kname, kvalue, size, flags);
> @@ -396,6 +404,17 @@ SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
>  	return error;
>  }
>  
> +static void
> +fix_xattr_to_user(const char *kname, void *kvalue, size_t size)
> +{
> +	if (strncmp(kname, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
> +		return;
> +	kname += XATTR_SYSTEM_PREFIX_LEN;
> +	if (!strcmp(kname, XATTR_POSIX_ACL_ACCESS) ||
> +	    !strcmp(kname, XATTR_POSIX_ACL_DEFAULT))
> +		posix_acl_fix_xattr_to_user(kvalue, size);
> +}
> +
>  /*
>   * Extended attribute GET operations
>   */
> @@ -426,9 +445,7 @@ getxattr(struct dentry *d, const char __user *name, void __user *value,
>  
>  	error = vfs_getxattr(d, kname, kvalue, size);
>  	if (error > 0) {
> -		if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
> -		    (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
> -			posix_acl_fix_xattr_to_user(kvalue, size);
> +		fix_xattr_to_user(kname, kvalue, size);
>  		if (size && copy_to_user(value, kvalue, error))
>  			error = -EFAULT;
>  	} else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {

Might be nice to move this one to the head of the queue. I don't see it
as being a controversial change, and it could go in before the rest of
the patches.

Reviewed-by: Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
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