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

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

[nick black]

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
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
 
 /**
  * smk_fetch - Fetch the smack label from a file.
-- 
                                      Nick Black <dankamongmen@acm.org>
                                             Principal Engineer, McAfee
                                  Grad student, GT College of Computing
                    "np: the class of dashed hopes, and idle dreams..."

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

[Pekka Enberg]

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

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

[nick black]

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Pekka Enberg left as an exercise for the reader:
> Hi Nick,
> 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.

Thanks for the review, Pekka, and I couldn't agree more. Here's a second
version of the patch, a rather more equal-opportunity unification
of magic numbers (I'll resend with a new Subject if that's preferred):

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/devpts/inode.c linux-2.6.31-rc1/fs/devpts/inode.c
--- linux-2.6.31-rc1-pristine/fs/devpts/inode.c	2009-06-24 19:25:37.000000000 -0400
+++ linux-2.6.31-rc1/fs/devpts/inode.c	2009-06-29 08:56:14.000000000 -0400
@@ -18,14 +18,13 @@
 #include <linux/mount.h>
 #include <linux/tty.h>
 #include <linux/mutex.h>
+#include <linux/magic.h>
 #include <linux/idr.h>
 #include <linux/devpts_fs.h>
 #include <linux/parser.h>
 #include <linux/fsnotify.h>
 #include <linux/seq_file.h>
 
-#define DEVPTS_SUPER_MAGIC 0x1cd1
-
 #define DEVPTS_DEFAULT_MODE 0600
 /*
  * ptmx is a new node in /dev/pts and will be unused in legacy (single-
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 08:55:57.000000000 -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
@@ -53,4 +54,8 @@
 #define INOTIFYFS_SUPER_MAGIC	0x2BAD1DEA
 
 #define STACK_END_MAGIC		0x57AC6E9D
+
+#define DEVPTS_SUPER_MAGIC	0x1cd1
+#define SOCKFS_MAGIC		0x534F434B
+
 #endif /* __LINUX_MAGIC_H__ */
diff -uprN -X linux-2.6.31-rc1-pristine/Documentation/dontdiff linux-2.6.31-rc1-pristine/net/socket.c linux-2.6.31-rc1/net/socket.c
--- linux-2.6.31-rc1-pristine/net/socket.c	2009-06-24 19:25:37.000000000 -0400
+++ linux-2.6.31-rc1/net/socket.c	2009-06-29 08:55:49.000000000 -0400
@@ -86,6 +86,7 @@
 #include <linux/audit.h>
 #include <linux/wireless.h>
 #include <linux/nsproxy.h>
+#include <linux/magic.h>
 
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
@@ -235,8 +236,6 @@ int move_addr_to_user(struct sockaddr *k
 	return __put_user(klen, ulen);
 }
 
-#define SOCKFS_MAGIC 0x534F434B
-
 static struct kmem_cache *sock_inode_cachep __read_mostly;
 
 static struct inode *sock_alloc_inode(struct super_block *sb)
Binary files linux-2.6.31-rc1-pristine/scripts/basic/hash and linux-2.6.31-rc1/scripts/basic/hash differ
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 08:54:50.000000000 -0400
@@ -30,17 +30,11 @@
 #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))
 
-/*
- * I hope these are the hokeyist lines of code in the module. Casey.
- */
-#define DEVPTS_SUPER_MAGIC	0x1cd1
-#define SOCKFS_MAGIC		0x534F434B
-#define TMPFS_MAGIC		0x01021994
-
 /**
  * smk_fetch - Fetch the smack label from a file.
  * @ip: a pointer to the inode

-- 
                                      Nick Black <dankamongmen@acm.org>
                                             Principal Engineer, McAfee
                                  Grad student, GT College of Computing
                    "np: the class of dashed hopes, and idle dreams..."

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

[Pekka Enberg]

On Mon, 2009-06-29 at 09:00 -0400, nick black wrote:
> Thanks for the review, Pekka, and I couldn't agree more. Here's a second
> version of the patch, a rather more equal-opportunity unification
> of magic numbers (I'll resend with a new Subject if that's preferred):
> 
> Signed-off-by: Nick Black <dank@qemfd.net>

Looks good to me!

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>

To both patches.

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

[nick black]

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nick black left as an exercise for the reader:
> Pekka Enberg left as an exercise for the reader:
> > Hi Nick,
> > 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.
> 
> Thanks for the review, Pekka, and I couldn't agree more. Here's a second
> version of the patch, a rather more equal-opportunity unification
> of magic numbers (I'll resend with a new Subject if that's preferred):

Ahh, I realize you want two patches. Here's the minimal hugetlbfs patch;
I'll send the magic number unification as another thread. My worry there is
whether SOCKFS_MAGIC and DEVPTS_SUPER_MAGIC ought be exposed to userspace --
[f]statfs(2)'s manpage makes it clear that HUGETLBFS_MAGIC is to be visible.

[f]statfs(2) *does* refer to DEVFS_SUPER_MAGIC, which doesn't exist anywhere
in the 2.6.31-rc1 tree. A typo, or legacy cruft from the devfs of yesteryear?
Either way, that doesn't answer whether SOCKFS_ ought be exported.

Thanks very much for the feedback!

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 08:55:57.000000000 -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

-- 
                                      Nick Black <dankamongmen@acm.org>
                                             Principal Engineer, McAfee
                                  Grad student, GT College of Computing
                    "np: the class of dashed hopes, and idle dreams..."

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