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_xattr.c b/fs/xfs/linux-2.6/xfs_xattr.c
index 964621f..497c7fb 100644
--- a/fs/xfs/linux-2.6/xfs_xattr.c
+++ b/fs/xfs/linux-2.6/xfs_xattr.c
@@ -29,67 +29,6 @@
 #include <linux/xattr.h>
 
 
-/*
- * ACL handling.  Should eventually be moved into xfs_acl.c
- */
-
-static int
-xfs_decode_acl(const char *name)
-{
-	if (strcmp(name, "posix_acl_access") == 0)
-		return _ACL_TYPE_ACCESS;
-	else if (strcmp(name, "posix_acl_default") == 0)
-		return _ACL_TYPE_DEFAULT;
-	return -EINVAL;
-}
-
-/*
- * Get system extended attributes which at the moment only
- * includes Posix ACLs.
- */
-static int
-xfs_xattr_system_get(struct inode *inode, const char *name,
-		void *buffer, size_t size)
-{
-	int acl;
-
-	acl = xfs_decode_acl(name);
-	if (acl < 0)
-		return acl;
-
-	return xfs_acl_vget(inode, buffer, size, acl);
-}
-
-static int
-xfs_xattr_system_set(struct inode *inode, const char *name,
-		const void *value, size_t size, int flags)
-{
-	int acl;
-
-	acl = xfs_decode_acl(name);
-	if (acl < 0)
-		return acl;
-	if (flags & XATTR_CREATE)
-		return -EINVAL;
-
-	if (!value)
-		return xfs_acl_vremove(inode, acl);
-
-	return xfs_acl_vset(inode, (void *)value, size, acl);
-}
-
-static struct xattr_handler xfs_xattr_system_handler = {
-	.prefix	= XATTR_SYSTEM_PREFIX,
-	.get	= xfs_xattr_system_get,
-	.set	= xfs_xattr_system_set,
-};
-
-
-/*
- * Real xattr handling.  The only difference between the namespaces is
- * a flag passed to the low-level attr code.
- */
-
 static int
 __xfs_xattr_get(struct inode *inode, const char *name,
 		void *value, size_t size, int xflags)
@@ -199,7 +138,9 @@
 	&xfs_xattr_user_handler,
 	&xfs_xattr_trusted_handler,
 	&xfs_xattr_security_handler,
+#ifdef CONFIG_XFS_POSIX_ACL
 	&xfs_xattr_system_handler,
+#endif
 	NULL
 };
 
@@ -310,7 +251,7 @@
 	/*
 	 * Then add the two synthetic ACL attributes.
 	 */
-	if (xfs_acl_vhasacl_access(inode)) {
+	if (posix_acl_access_exists(inode)) {
 		error = list_one_attr(POSIX_ACL_XATTR_ACCESS,
 				strlen(POSIX_ACL_XATTR_ACCESS) + 1,
 				data, size, &context.count);
@@ -318,7 +259,7 @@
 			return error;
 	}
 
-	if (xfs_acl_vhasacl_default(inode)) {
+	if (posix_acl_default_exists(inode)) {
 		error = list_one_attr(POSIX_ACL_XATTR_DEFAULT,
 				strlen(POSIX_ACL_XATTR_DEFAULT) + 1,
 				data, size, &context.count);