xfs: use generic Posix ACL code

This patch rips out the XFS ACL handling code and uses the generic
fs/posix_acl.c code instead.  The ondisk format is of course left
unchanged.

This also introduces the same ACL caching all other Linux filesystems do
by adding pointers to the acl and default acl in struct xfs_inode.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Sandeen <sandeen@sandeen.net>
diff --git a/fs/xfs/linux-2.6/xfs_iops.c b/fs/xfs/linux-2.6/xfs_iops.c
index 631d013..84e391a 100644
--- a/fs/xfs/linux-2.6/xfs_iops.c
+++ b/fs/xfs/linux-2.6/xfs_iops.c
@@ -17,6 +17,7 @@
  */
 #include "xfs.h"
 #include "xfs_fs.h"
+#include "xfs_acl.h"
 #include "xfs_bit.h"
 #include "xfs_log.h"
 #include "xfs_inum.h"
@@ -51,6 +52,7 @@
 #include <linux/capability.h>
 #include <linux/xattr.h>
 #include <linux/namei.h>
+#include <linux/posix_acl.h>
 #include <linux/security.h>
 #include <linux/falloc.h>
 #include <linux/fiemap.h>
@@ -202,9 +204,8 @@
 {
 	struct inode	*inode;
 	struct xfs_inode *ip = NULL;
-	xfs_acl_t	*default_acl = NULL;
+	struct posix_acl *default_acl = NULL;
 	struct xfs_name	name;
-	int (*test_default_acl)(struct inode *) = _ACL_DEFAULT_EXISTS;
 	int		error;
 
 	/*
@@ -219,18 +220,14 @@
 		rdev = 0;
 	}
 
-	if (test_default_acl && test_default_acl(dir)) {
-		if (!_ACL_ALLOC(default_acl)) {
-			return -ENOMEM;
-		}
-		if (!_ACL_GET_DEFAULT(dir, default_acl)) {
-			_ACL_FREE(default_acl);
-			default_acl = NULL;
-		}
-	}
+	if (IS_POSIXACL(dir)) {
+		default_acl = xfs_get_acl(dir, ACL_TYPE_DEFAULT);
+		if (IS_ERR(default_acl))
+			return -PTR_ERR(default_acl);
 
-	if (IS_POSIXACL(dir) && !default_acl)
-		mode &= ~current->fs->umask;
+		if (!default_acl)
+			mode &= ~current->fs->umask;
+	}
 
 	xfs_dentry_to_name(&name, dentry);
 	error = xfs_create(XFS_I(dir), &name, mode, rdev, &ip, NULL);
@@ -244,10 +241,10 @@
 		goto out_cleanup_inode;
 
 	if (default_acl) {
-		error = _ACL_INHERIT(inode, mode, default_acl);
+		error = -xfs_inherit_acl(inode, default_acl);
 		if (unlikely(error))
 			goto out_cleanup_inode;
-		_ACL_FREE(default_acl);
+		posix_acl_release(default_acl);
 	}
 
 
@@ -257,8 +254,7 @@
  out_cleanup_inode:
 	xfs_cleanup_inode(dir, inode, dentry);
  out_free_acl:
-	if (default_acl)
-		_ACL_FREE(default_acl);
+	posix_acl_release(default_acl);
 	return -error;
 }
 
@@ -488,26 +484,6 @@
 		kfree(s);
 }
 
-#ifdef CONFIG_XFS_POSIX_ACL
-STATIC int
-xfs_check_acl(
-	struct inode		*inode,
-	int			mask)
-{
-	struct xfs_inode	*ip = XFS_I(inode);
-	int			error;
-
-	xfs_itrace_entry(ip);
-
-	if (XFS_IFORK_Q(ip)) {
-		error = xfs_acl_iaccess(ip, mask, NULL);
-		if (error != -1)
-			return -error;
-	}
-
-	return -EAGAIN;
-}
-
 STATIC int
 xfs_vn_permission(
 	struct inode		*inode,
@@ -515,9 +491,6 @@
 {
 	return generic_permission(inode, mask, xfs_check_acl);
 }
-#else
-#define xfs_vn_permission NULL
-#endif
 
 STATIC int
 xfs_vn_getattr(