Re: [PATCH] hugetlbfs: publish HUGETLBFS_MAGIC via linux/magic.h

[Pekka Enberg <penberg@cs.helsinki.fi>]

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