From 670508f080ebad88825344d0670537becdaa943e Mon Sep 17 00:00:00 2001
From: Chunwei Chen <david.chen@osnexus.com>
Date: Wed, 19 Oct 2016 11:19:17 -0700
Subject: [PATCH] Linux 4.9 compat: remove iops->{set,get,remove}xattr

In Linux 4.9, torvalds/linux@fd50eca, iops->{set,get,remove}xattr and
generic_{set,get,remove}xattr are removed. xattr operations will directly
go through sb->s_xattr.

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
---
 config/kernel-xattr-handler.m4 | 25 +++++++++++++++++++++++++
 config/kernel.m4               |  1 +
 module/zfs/zpl_inode.c         |  8 ++++++++
 3 files changed, 34 insertions(+)

diff --git a/config/kernel-xattr-handler.m4 b/config/kernel-xattr-handler.m4
index dcffd4480c..4ac08d8e7e 100644
--- a/config/kernel-xattr-handler.m4
+++ b/config/kernel-xattr-handler.m4
@@ -57,6 +57,31 @@ AC_DEFUN([ZFS_AC_KERNEL_XATTR_HANDLER_NAME], [
 	])
 ])
 
+dnl #
+dnl # 4.9 API change,
+dnl # iops->{set,get,remove}xattr and generic_{set,get,remove}xattr are
+dnl # removed. xattr operations will directly go through sb->s_xattr.
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_HAVE_GENERIC_SETXATTR], [
+	AC_MSG_CHECKING([whether generic_setxattr() exists])
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/fs.h>
+		#include <linux/xattr.h>
+
+		static const struct inode_operations
+		    iops __attribute__ ((unused)) = {
+			.setxattr = generic_setxattr
+		};
+	],[
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_GENERIC_SETXATTR, 1,
+		    [generic_setxattr() exists])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])
+
 dnl #
 dnl # Supported xattr handler get() interfaces checked newest to oldest.
 dnl #
diff --git a/config/kernel.m4 b/config/kernel.m4
index 9405ae6f9f..a007a4c91e 100644
--- a/config/kernel.m4
+++ b/config/kernel.m4
@@ -100,6 +100,7 @@ AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [
 	ZFS_AC_KERNEL_MAKE_REQUEST_FN
 	ZFS_AC_KERNEL_GENERIC_IO_ACCT
 	ZFS_AC_KERNEL_RENAME_WANTS_FLAGS
+	ZFS_AC_KERNEL_HAVE_GENERIC_SETXATTR
 
 	AS_IF([test "$LINUX_OBJ" != "$LINUX"], [
 		KERNELMAKE_PARAMS="$KERNELMAKE_PARAMS O=$LINUX_OBJ"
diff --git a/module/zfs/zpl_inode.c b/module/zfs/zpl_inode.c
index d8490ffcca..d609f518bc 100644
--- a/module/zfs/zpl_inode.c
+++ b/module/zfs/zpl_inode.c
@@ -661,9 +661,11 @@ zpl_revalidate(struct dentry *dentry, unsigned int flags)
 const struct inode_operations zpl_inode_operations = {
 	.setattr	= zpl_setattr,
 	.getattr	= zpl_getattr,
+#ifdef HAVE_GENERIC_SETXATTR
 	.setxattr	= generic_setxattr,
 	.getxattr	= generic_getxattr,
 	.removexattr	= generic_removexattr,
+#endif
 	.listxattr	= zpl_xattr_list,
 #ifdef HAVE_INODE_TRUNCATE_RANGE
 	.truncate_range = zpl_truncate_range,
@@ -698,9 +700,11 @@ const struct inode_operations zpl_dir_inode_operations = {
 #endif
 	.setattr	= zpl_setattr,
 	.getattr	= zpl_getattr,
+#ifdef HAVE_GENERIC_SETXATTR
 	.setxattr	= generic_setxattr,
 	.getxattr	= generic_getxattr,
 	.removexattr	= generic_removexattr,
+#endif
 	.listxattr	= zpl_xattr_list,
 #if defined(CONFIG_FS_POSIX_ACL)
 #if defined(HAVE_GET_ACL)
@@ -725,18 +729,22 @@ const struct inode_operations zpl_symlink_inode_operations = {
 #endif
 	.setattr	= zpl_setattr,
 	.getattr	= zpl_getattr,
+#ifdef HAVE_GENERIC_SETXATTR
 	.setxattr	= generic_setxattr,
 	.getxattr	= generic_getxattr,
 	.removexattr	= generic_removexattr,
+#endif
 	.listxattr	= zpl_xattr_list,
 };
 
 const struct inode_operations zpl_special_inode_operations = {
 	.setattr	= zpl_setattr,
 	.getattr	= zpl_getattr,
+#ifdef HAVE_GENERIC_SETXATTR
 	.setxattr	= generic_setxattr,
 	.getxattr	= generic_getxattr,
 	.removexattr	= generic_removexattr,
+#endif
 	.listxattr	= zpl_xattr_list,
 #if defined(CONFIG_FS_POSIX_ACL)
 #if defined(HAVE_GET_ACL)