diff mbox series

[v2] ext4: support xattr gnu.* namespace for the Hurd

Message ID 20200525193940.878-1-janneke@gnu.org
State Awaiting Upstream
Headers show
Series [v2] ext4: support xattr gnu.* namespace for the Hurd | expand

Commit Message

Jan Nieuwenhuizen May 25, 2020, 7:39 p.m. UTC
The Hurd gained[0] support for moving the translator and author
fields out of the inode and into the "gnu.*" xattr namespace.

In anticipation of that, an xattr INDEX was reserved[1].  The Hurd has
now been brought into compliance[2] with that.

This patch adds support for reading and writing such attributes from
Linux; you can now do something like

    mkdir -p hurd-root/servers/socket
    touch hurd-root/servers/socket/1
    setfattr --name=gnu.translator --value='"/hurd/pflocal\0"' \
        hurd-root/servers/socket/1
    getfattr --name=gnu.translator hurd-root/servers/socket/1
    # file: 1
    gnu.translator="/hurd/pflocal"

to setup a pipe translator, which is being used to create[3] a
vm-image for the Hurd from GNU Guix.

[0] https://summerofcode.withgoogle.com/projects/#5869799859027968
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3980bd3b406addb327d858aebd19e229ea340b9a
[2] https://git.savannah.gnu.org/cgit/hurd/hurd.git/commit/?id=a04c7bf83172faa7cb080fbe3b6c04a8415ca645
[3] https://git.savannah.gnu.org/cgit/guix.git/log/?h=wip-hurd-vm
---
 fs/ext4/Makefile           |  3 ++-
 fs/ext4/xattr.c            |  2 ++
 fs/ext4/xattr.h            |  1 +
 fs/ext4/xattr_hurd.c       | 51 ++++++++++++++++++++++++++++++++++++++
 include/uapi/linux/xattr.h |  4 +++
 5 files changed, 60 insertions(+), 1 deletion(-)
 create mode 100644 fs/ext4/xattr_hurd.c

Comments

Theodore Y. Ts'o May 29, 2020, 3:25 a.m. UTC | #1
On Mon, May 25, 2020 at 09:39:40PM +0200, Jan (janneke) Nieuwenhuizen wrote:
> The Hurd gained[0] support for moving the translator and author
> fields out of the inode and into the "gnu.*" xattr namespace.
> 
> In anticipation of that, an xattr INDEX was reserved[1].  The Hurd has
> now been brought into compliance[2] with that.
> 
> This patch adds support for reading and writing such attributes from
> Linux; you can now do something like
> 
>     mkdir -p hurd-root/servers/socket
>     touch hurd-root/servers/socket/1
>     setfattr --name=gnu.translator --value='"/hurd/pflocal\0"' \
>         hurd-root/servers/socket/1
>     getfattr --name=gnu.translator hurd-root/servers/socket/1
>     # file: 1
>     gnu.translator="/hurd/pflocal"
> 
> to setup a pipe translator, which is being used to create[3] a
> vm-image for the Hurd from GNU Guix.
> 
> [0] https://summerofcode.withgoogle.com/projects/#5869799859027968
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3980bd3b406addb327d858aebd19e229ea340b9a
> [2] https://git.savannah.gnu.org/cgit/hurd/hurd.git/commit/?id=a04c7bf83172faa7cb080fbe3b6c04a8415ca645
> [3] https://git.savannah.gnu.org/cgit/guix.git/log/?h=wip-hurd-vm

This patch is missing a Signed-off-by.  If you don't understand why
this is really important, please read: 

https://www.kernel.org/doc/html/latest/process/submitting-patches.html#sign-your-work-the-developer-s-certificate-of-origin

Can you resubmit with the DCO or confirm that it's OK for me to add your Signed-off-by?

    		      	      	 	      - Ted
Jan Nieuwenhuizen May 29, 2020, 8:39 a.m. UTC | #2
Theodore Y. Ts'o writes:

Hello!

> On Mon, May 25, 2020 at 09:39:40PM +0200, Jan (janneke) Nieuwenhuizen wrote:
>> The Hurd gained[0] support for moving the translator and author
>> fields out of the inode and into the "gnu.*" xattr namespace.
>> 
>> In anticipation of that, an xattr INDEX was reserved[1].  The Hurd has
>> now been brought into compliance[2] with that.
>> 
>> This patch adds support for reading and writing such attributes from
>> Linux; you can now do something like

[...]
>
> This patch is missing a Signed-off-by.  If you don't understand why
> this is really important, please read: 
>
> https://www.kernel.org/doc/html/latest/process/submitting-patches.html#sign-your-work-the-developer-s-certificate-of-origin

Ah, that makes sense.  Sorry for omitting that/being not clear on it.

> Can you resubmit with the DCO or confirm that it's OK for me to add
> your Signed-off-by?

Yes, that's OK, please do!  I am the original author of this patch.

Greetings,
Janneke
Theodore Y. Ts'o June 12, 2020, 5:38 p.m. UTC | #3
On Fri, May 29, 2020 at 10:39:39AM +0200, Jan Nieuwenhuizen wrote:
> Theodore Y. Ts'o writes:
> 
> Hello!
> 
> > On Mon, May 25, 2020 at 09:39:40PM +0200, Jan (janneke) Nieuwenhuizen wrote:
> >> The Hurd gained[0] support for moving the translator and author
> >> fields out of the inode and into the "gnu.*" xattr namespace.
> >> 
> >> In anticipation of that, an xattr INDEX was reserved[1].  The Hurd has
> >> now been brought into compliance[2] with that.
> >> 
> >> This patch adds support for reading and writing such attributes from
> >> Linux; you can now do something like
> 
> [...]
> >
> > This patch is missing a Signed-off-by.  If you don't understand why
> > this is really important, please read: 
> >
> > https://www.kernel.org/doc/html/latest/process/submitting-patches.html#sign-your-work-the-developer-s-certificate-of-origin
> 
> Ah, that makes sense.  Sorry for omitting that/being not clear on it.
> 
> > Can you resubmit with the DCO or confirm that it's OK for me to add
> > your Signed-off-by?
> 
> Yes, that's OK, please do!  I am the original author of this patch.

Thanks, I've applied this to the ext4.git tree.

						- Ted
diff mbox series

Patch

diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile
index 4ccb3c9189d8..2e42f47a7f98 100644
--- a/fs/ext4/Makefile
+++ b/fs/ext4/Makefile
@@ -9,7 +9,8 @@  ext4-y	:= balloc.o bitmap.o block_validity.o dir.o ext4_jbd2.o extents.o \
 		extents_status.o file.o fsmap.o fsync.o hash.o ialloc.o \
 		indirect.o inline.o inode.o ioctl.o mballoc.o migrate.o \
 		mmp.o move_extent.o namei.o page-io.o readpage.o resize.o \
-		super.o symlink.o sysfs.o xattr.o xattr_trusted.o xattr_user.o
+		super.o symlink.o sysfs.o xattr.o xattr_hurd.o xattr_trusted.o \
+		xattr_user.o
 
 ext4-$(CONFIG_EXT4_FS_POSIX_ACL)	+= acl.o
 ext4-$(CONFIG_EXT4_FS_SECURITY)		+= xattr_security.o
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 9b29a40738ac..7d2f6576d954 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -93,6 +93,7 @@  static const struct xattr_handler * const ext4_xattr_handler_map[] = {
 #ifdef CONFIG_EXT4_FS_SECURITY
 	[EXT4_XATTR_INDEX_SECURITY]	     = &ext4_xattr_security_handler,
 #endif
+	[EXT4_XATTR_INDEX_HURD]		     = &ext4_xattr_hurd_handler,
 };
 
 const struct xattr_handler *ext4_xattr_handlers[] = {
@@ -105,6 +106,7 @@  const struct xattr_handler *ext4_xattr_handlers[] = {
 #ifdef CONFIG_EXT4_FS_SECURITY
 	&ext4_xattr_security_handler,
 #endif
+	&ext4_xattr_hurd_handler,
 	NULL
 };
 
diff --git a/fs/ext4/xattr.h b/fs/ext4/xattr.h
index ffe21ac77f78..730b91fa0dd7 100644
--- a/fs/ext4/xattr.h
+++ b/fs/ext4/xattr.h
@@ -124,6 +124,7 @@  struct ext4_xattr_inode_array {
 extern const struct xattr_handler ext4_xattr_user_handler;
 extern const struct xattr_handler ext4_xattr_trusted_handler;
 extern const struct xattr_handler ext4_xattr_security_handler;
+extern const struct xattr_handler ext4_xattr_hurd_handler;
 
 #define EXT4_XATTR_NAME_ENCRYPTION_CONTEXT "c"
 
diff --git a/fs/ext4/xattr_hurd.c b/fs/ext4/xattr_hurd.c
new file mode 100644
index 000000000000..8cfa74a56361
--- /dev/null
+++ b/fs/ext4/xattr_hurd.c
@@ -0,0 +1,51 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/ext4/xattr_hurd.c
+ * Handler for extended gnu attributes for the Hurd.
+ *
+ * Copyright (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
+ * Copyright (C) 2020 by Jan (janneke) Nieuwenhuizen, <janneke@gnu.org>
+ */
+
+#include <linux/init.h>
+#include <linux/string.h>
+#include "ext4.h"
+#include "xattr.h"
+
+static bool
+ext4_xattr_hurd_list(struct dentry *dentry)
+{
+	return test_opt(dentry->d_sb, XATTR_USER);
+}
+
+static int
+ext4_xattr_hurd_get(const struct xattr_handler *handler,
+		    struct dentry *unused, struct inode *inode,
+		    const char *name, void *buffer, size_t size)
+{
+	if (!test_opt(inode->i_sb, XATTR_USER))
+		return -EOPNOTSUPP;
+
+	return ext4_xattr_get(inode, EXT4_XATTR_INDEX_HURD,
+			      name, buffer, size);
+}
+
+static int
+ext4_xattr_hurd_set(const struct xattr_handler *handler,
+		    struct dentry *unused, struct inode *inode,
+		    const char *name, const void *value,
+		    size_t size, int flags)
+{
+	if (!test_opt(inode->i_sb, XATTR_USER))
+		return -EOPNOTSUPP;
+
+	return ext4_xattr_set(inode, EXT4_XATTR_INDEX_HURD,
+			      name, value, size, flags);
+}
+
+const struct xattr_handler ext4_xattr_hurd_handler = {
+	.prefix	= XATTR_HURD_PREFIX,
+	.list	= ext4_xattr_hurd_list,
+	.get	= ext4_xattr_hurd_get,
+	.set	= ext4_xattr_hurd_set,
+};
diff --git a/include/uapi/linux/xattr.h b/include/uapi/linux/xattr.h
index c1395b5bd432..9463db2dfa9d 100644
--- a/include/uapi/linux/xattr.h
+++ b/include/uapi/linux/xattr.h
@@ -7,6 +7,7 @@ 
   Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org>
   Copyright (c) 2001-2002 Silicon Graphics, Inc.  All Rights Reserved.
   Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
+  Copyright (c) 2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
 */
 
 #include <linux/libc-compat.h>
@@ -31,6 +32,9 @@ 
 #define XATTR_BTRFS_PREFIX "btrfs."
 #define XATTR_BTRFS_PREFIX_LEN (sizeof(XATTR_BTRFS_PREFIX) - 1)
 
+#define XATTR_HURD_PREFIX "gnu."
+#define XATTR_HURD_PREFIX_LEN (sizeof(XATTR_HURD_PREFIX) - 1)
+
 #define XATTR_SECURITY_PREFIX	"security."
 #define XATTR_SECURITY_PREFIX_LEN (sizeof(XATTR_SECURITY_PREFIX) - 1)