From b8d9e26440ade0edebfa98af8cb9371810c1aeaf Mon Sep 17 00:00:00 2001
From: Chunwei Chen <david.chen@osnexus.com>
Date: Wed, 19 Oct 2016 11:19:01 -0700
Subject: [PATCH] Linux 4.9 compat: iops->rename() wants flags

In Linux 4.9, torvalds/linux@2773bf0, iops->rename() and iops->rename2() are
merged together into iops->rename(), it now wants flags.

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
---
 config/kernel-rename.m4 | 25 +++++++++++++++++++++++++
 config/kernel.m4        |  1 +
 module/zfs/zpl_ctldir.c | 23 ++++++++++++++++++++---
 module/zfs/zpl_inode.c  | 21 +++++++++++++++++++--
 4 files changed, 65 insertions(+), 5 deletions(-)
 create mode 100644 config/kernel-rename.m4

diff --git a/config/kernel-rename.m4 b/config/kernel-rename.m4
new file mode 100644
index 000000000..9f894fb4d
--- /dev/null
+++ b/config/kernel-rename.m4
@@ -0,0 +1,25 @@
+dnl #
+dnl # 4.9 API change,
+dnl # iops->rename2() merged into iops->rename(), and iops->rename() now wants
+dnl # flags.
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_RENAME_WANTS_FLAGS], [
+	AC_MSG_CHECKING([whether iops->rename() wants flags])
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/fs.h>
+		int rename_fn(struct inode *sip, struct dentry *sdp,
+			struct inode *tip, struct dentry *tdp,
+			unsigned int flags) { return 0; }
+
+		static const struct inode_operations
+		    iops __attribute__ ((unused)) = {
+			.rename = rename_fn,
+		};
+	],[
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_RENAME_WANTS_FLAGS, 1, [iops->rename() wants flags])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])
diff --git a/config/kernel.m4 b/config/kernel.m4
index c53e61157..37635256b 100644
--- a/config/kernel.m4
+++ b/config/kernel.m4
@@ -103,6 +103,7 @@ AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [
 	ZFS_AC_KERNEL_FPU
 	ZFS_AC_KERNEL_KUID_HELPERS
 	ZFS_AC_KERNEL_MODULE_PARAM_CALL_CONST
+	ZFS_AC_KERNEL_RENAME_WANTS_FLAGS
 
 	AS_IF([test "$LINUX_OBJ" != "$LINUX"], [
 		KERNELMAKE_PARAMS="$KERNELMAKE_PARAMS O=$LINUX_OBJ"
diff --git a/module/zfs/zpl_ctldir.c b/module/zfs/zpl_ctldir.c
index 7c4fcea3e..cdd6668b1 100644
--- a/module/zfs/zpl_ctldir.c
+++ b/module/zfs/zpl_ctldir.c
@@ -301,13 +301,17 @@ zpl_snapdir_readdir(struct file *filp, void *dirent, filldir_t filldir)
 }
 #endif /* HAVE_VFS_ITERATE */
 
-int
-zpl_snapdir_rename(struct inode *sdip, struct dentry *sdentry,
-    struct inode *tdip, struct dentry *tdentry)
+static int
+zpl_snapdir_rename2(struct inode *sdip, struct dentry *sdentry,
+    struct inode *tdip, struct dentry *tdentry, unsigned int flags)
 {
 	cred_t *cr = CRED();
 	int error;
 
+	/* We probably don't want to support renameat2(2) in ctldir */
+	if (flags)
+		return (-EINVAL);
+
 	crhold(cr);
 	error = -zfsctl_snapdir_rename(sdip, dname(sdentry),
 	    tdip, dname(tdentry), cr, 0);
@@ -317,6 +321,15 @@ zpl_snapdir_rename(struct inode *sdip, struct dentry *sdentry,
 	return (error);
 }
 
+#ifndef HAVE_RENAME_WANTS_FLAGS
+static int
+zpl_snapdir_rename(struct inode *sdip, struct dentry *sdentry,
+    struct inode *tdip, struct dentry *tdentry)
+{
+	return (zpl_snapdir_rename2(sdip, sdentry, tdip, tdentry, 0));
+}
+#endif
+
 static int
 zpl_snapdir_rmdir(struct inode *dip, struct dentry *dentry)
 {
@@ -405,7 +418,11 @@ const struct file_operations zpl_fops_snapdir = {
 const struct inode_operations zpl_ops_snapdir = {
 	.lookup		= zpl_snapdir_lookup,
 	.getattr	= zpl_snapdir_getattr,
+#ifdef HAVE_RENAME_WANTS_FLAGS
+	.rename		= zpl_snapdir_rename2,
+#else
 	.rename		= zpl_snapdir_rename,
+#endif
 	.rmdir		= zpl_snapdir_rmdir,
 	.mkdir		= zpl_snapdir_mkdir,
 };
diff --git a/module/zfs/zpl_inode.c b/module/zfs/zpl_inode.c
index d26193ffa..113885ead 100644
--- a/module/zfs/zpl_inode.c
+++ b/module/zfs/zpl_inode.c
@@ -356,13 +356,17 @@ zpl_setattr(struct dentry *dentry, struct iattr *ia)
 }
 
 static int
-zpl_rename(struct inode *sdip, struct dentry *sdentry,
-    struct inode *tdip, struct dentry *tdentry)
+zpl_rename2(struct inode *sdip, struct dentry *sdentry,
+    struct inode *tdip, struct dentry *tdentry, unsigned int flags)
 {
 	cred_t *cr = CRED();
 	int error;
 	fstrans_cookie_t cookie;
 
+	/* We don't have renameat2(2) support */
+	if (flags)
+		return (-EINVAL);
+
 	crhold(cr);
 	cookie = spl_fstrans_mark();
 	error = -zfs_rename(sdip, dname(sdentry), tdip, dname(tdentry), cr, 0);
@@ -373,6 +377,15 @@ zpl_rename(struct inode *sdip, struct dentry *sdentry,
 	return (error);
 }
 
+#ifndef HAVE_RENAME_WANTS_FLAGS
+static int
+zpl_rename(struct inode *sdip, struct dentry *sdentry,
+    struct inode *tdip, struct dentry *tdentry)
+{
+	return (zpl_rename2(sdip, sdentry, tdip, tdentry, 0));
+}
+#endif
+
 static int
 zpl_symlink(struct inode *dir, struct dentry *dentry, const char *name)
 {
@@ -681,7 +694,11 @@ const struct inode_operations zpl_dir_inode_operations = {
 	.mkdir		= zpl_mkdir,
 	.rmdir		= zpl_rmdir,
 	.mknod		= zpl_mknod,
+#ifdef HAVE_RENAME_WANTS_FLAGS
+	.rename		= zpl_rename2,
+#else
 	.rename		= zpl_rename,
+#endif
 	.setattr	= zpl_setattr,
 	.getattr	= zpl_getattr,
 	.setxattr	= generic_setxattr,