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In-Reply-To: <20090629121657.GA9848@qemfd.net>
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Date: Mon, 29 Jun 2009 15:39:26 +0300
Message-ID: <84144f020906290539m3d24af6ap37f9da9371b786dd@mail.gmail.com>
Subject: Re: [PATCH] hugetlbfs: publish HUGETLBFS_MAGIC via linux/magic.h
From: Pekka Enberg <penberg@cs.helsinki.fi>
To: nick black <dank@qemfd.net>
Cc: William Irwin <wli@holomorphy.com>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       man-pages <mtk.manpages@gmail.com>, linux-kernel@vger.kernel.org,
       Andrew Morton <akpm@linux-foundation.org>, casey@schaufler-ca.com,
       jmorris@namei.org
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Hi Nick,

On Mon, Jun 29, 2009 at 3:16 PM, nick black<dank@qemfd.net> wrote:
> statfs(2)'s man page (release 3.21) lists HUGETLBFS_MAGIC among the other
> constants, as one would expect. It's not actually exported, though; it's
> buried within inode.c in fs/hugetlbfs/ (iirc, the kvm userland code has
> cut-and-pasted the definition into their sources). This patch brings the
> exported interface into conformance with documentation, is necessary for
> [f]statfs(2)-based verification of hugetlbfs mounts, and eliminates a
> duplicate definition of TMPFS_MAGIC floating around in smack_lsm.c.
>
> This is against 2.6.30-rc1. --rigorously, nick
> Signed-off-by: Nick Black <dank@qemfd.net>

> diff -uprN -X linux-2.6.31-rc1-pristine/Documentation/dontdiff linux-2.6.31-rc1-pristine/fs/hugetlbfs/inode.c linux-2.6.31-rc1/fs/hugetlbfs/inode.c
> --- linux-2.6.31-rc1-pristine/fs/hugetlbfs/inode.c ? ? ?2009-06-24 19:25:37.000000000 -0400
> +++ linux-2.6.31-rc1/fs/hugetlbfs/inode.c ? ? ? 2009-06-29 07:52:43.000000000 -0400
> @@ -31,12 +31,10 @@
> ?#include <linux/statfs.h>
> ?#include <linux/security.h>
> ?#include <linux/ima.h>
> +#include <linux/magic.h>
>
> ?#include <asm/uaccess.h>
>
> -/* some random number */
> -#define HUGETLBFS_MAGIC ? ? ? ?0x958458f6
> -
> ?static const struct super_operations hugetlbfs_ops;
> ?static const struct address_space_operations hugetlbfs_aops;
> ?const struct file_operations hugetlbfs_file_operations;
> diff -uprN -X linux-2.6.31-rc1-pristine/Documentation/dontdiff linux-2.6.31-rc1-pristine/include/linux/magic.h linux-2.6.31-rc1/include/linux/magic.h
> --- linux-2.6.31-rc1-pristine/include/linux/magic.h ? ? 2009-06-24 19:25:37.000000000 -0400
> +++ linux-2.6.31-rc1/include/linux/magic.h ? ? ?2009-06-29 07:58:15.000000000 -0400
> @@ -13,6 +13,7 @@
> ?#define SECURITYFS_MAGIC ? ? ? 0x73636673
> ?#define SELINUX_MAGIC ? ? ? ? ?0xf97cff8c
> ?#define TMPFS_MAGIC ? ? ? ? ? ?0x01021994
> +#define HUGETLBFS_MAGIC ? ? ? ?0x958458f6 ? ? ?/* some random number */
> ?#define SQUASHFS_MAGIC ? ? ? ? 0x73717368
> ?#define EFS_SUPER_MAGIC ? ? ? ? ? ? ? ?0x414A53
> ?#define EXT2_SUPER_MAGIC ? ? ? 0xEF53

Looks good to me.

> diff -uprN -X linux-2.6.31-rc1-pristine/Documentation/dontdiff linux-2.6.31-rc1-pristine/security/smack/smack_lsm.c linux-2.6.31-rc1/security/smack/smack_lsm.c
> --- linux-2.6.31-rc1-pristine/security/smack/smack_lsm.c ? ? ? ?2009-06-24 19:25:37.000000000 -0400
> +++ linux-2.6.31-rc1/security/smack/smack_lsm.c 2009-06-29 07:54:28.000000000 -0400
> @@ -30,6 +30,7 @@
> ?#include <net/netlabel.h>
> ?#include <net/cipso_ipv4.h>
> ?#include <linux/audit.h>
> +#include <linux/magic.h>
> ?#include "smack.h"
>
> ?#define task_security(task) ? ?(task_cred_xxx((task), security))
> @@ -39,7 +40,6 @@
> ?*/
> ?#define DEVPTS_SUPER_MAGIC ? ? 0x1cd1
> ?#define SOCKFS_MAGIC ? ? ? ? ? 0x534F434B
> -#define TMPFS_MAGIC ? ? ? ? ? ?0x01021994

This looks good to me as well but it should be a separate patch as the
change has nothing to do with hugetlbfs. While at it, you should
probably move SOCKFS_MAGIC and DEVPTS_SUPER_MAGIC to <linux/magic.h>
and remove the definitions from smack.

                                        Pekka
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