Posix ACL Support

This change adds support for Posix ACLs by storing them as an xattr
which is common practice for many Linux file systems.  Since the
Posix ACL is stored as an xattr it will not overwrite any existing
ZFS/NFSv4 ACLs which may have been set.  The Posix ACL will also
be non-functional on other platforms although it may be visible
as an xattr if that platform understands SA based xattrs.

By default Posix ACLs are disabled but they may be enabled with
the new 'aclmode=noacl|posixacl' property.  Set the property to
'posixacl' to enable them.  If ZFS/NFSv4 ACL support is ever added
an appropriate acltype will be added.

This change passes the POSIX Test Suite cleanly with the exception
of xacl/00.t test 45 which is incorrect for Linux (Ext4 fails too).

  http://www.tuxera.com/community/posix-test-suite/

Signed-off-by: Massimo Maggi <[email protected]>
Signed-off-by: Richard Yao <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #170

1 files changed, 69 insertions, 0 deletions

diff --git a/config/kernel-xattr-handler.m4 b/config/kernel-xattr-handler.m4
index 943f9033c..2ba2fcbcd 100644
--- a/config/kernel-xattr-handler.m4
+++ b/config/kernel-xattr-handler.m4
@@ -84,3 +84,72 @@ AC_DEFUN([ZFS_AC_KERNEL_XATTR_HANDLER_SET], [
 		AC_MSG_RESULT(no)
 	])
 ])
+
+dnl #
+dnl # 2.6.33 API change,
+dnl # The xattr_hander->list() callback was changed to take a dentry
+dnl # instead of an inode, and a handler_flags argument was added.
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_XATTR_HANDLER_LIST], [
+	AC_MSG_CHECKING([whether xattr_handler->list() wants dentry])
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/xattr.h>
+
+		size_t list(struct dentry *dentry, char *list, size_t list_size,
+		    const char *name, size_t name_len, int handler_flags)
+		    { return 0; }
+		static const struct xattr_handler
+		    xops __attribute__ ((unused)) = {
+			.list = list,
+		};
+	],[
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_DENTRY_XATTR_LIST, 1,
+		    [xattr_handler->list() wants dentry])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])
+
+dnl #
+dnl # 3.7 API change,
+dnl # The posix_acl_{from,to}_xattr functions gained a new
+dnl # parameter: user_ns
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_POSIX_ACL_FROM_XATTR_USERNS], [
+	AC_MSG_CHECKING([whether posix_acl_from_xattr() needs user_ns])
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/cred.h>
+		#include <linux/fs.h>
+		#include <linux/posix_acl_xattr.h>
+	],[
+		posix_acl_from_xattr(&init_user_ns, NULL, 0);
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_POSIX_ACL_FROM_XATTR_USERNS, 1,
+		    [posix_acl_from_xattr() needs user_ns])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])
+
+dnl #
+dnl # 2.6.39 API change,
+dnl # The is_owner_or_cap() macro was replaced by inode_owner_or_capable(),
+dnl # this is used for permission checks in the xattr call paths.
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_INODE_OWNER_OR_CAPABLE], [
+	AC_MSG_CHECKING([whether inode_owner_or_capable() exists])
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/fs.h>
+	],[
+		inode_owner_or_capable(NULL);
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_INODE_OWNER_OR_CAPABLE, 1,
+		    [inode_owner_or_capable() exists])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])