Simplify BDI integration

Update the code to use the bdi_setup_and_register() helper to
simplify the bdi integration code.  The updated code now just
registers the bdi during mount and destroys it during unmount.

The only complication is that for 2.6.32 - 2.6.33 kernels the
helper wasn't available so in these cases the zfs code must
provide it.  Luckily the bdi_setup_and_register() function
is trivial.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #367

Makefile.in

@@ -56,6 +56,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

cmd/Makefile.in

@@ -41,6 +41,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

cmd/mount_zfs/Makefile.in

@@ -44,6 +44,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

cmd/sas_switch_id/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

cmd/zdb/Makefile.in

@@ -44,6 +44,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

cmd/zfs/Makefile.in

@@ -44,6 +44,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

cmd/zinject/Makefile.in

@@ -44,6 +44,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

cmd/zpios/Makefile.in

@@ -44,6 +44,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

cmd/zpool/Makefile.in

@@ -44,6 +44,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

cmd/zpool_id/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

cmd/zpool_layout/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

cmd/ztest/Makefile.in

@@ -44,6 +44,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

cmd/zvol_id/Makefile.in

@@ -44,6 +44,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

config/kernel-bdi-setup-and-register.m4

@@ -0,0 +1,15 @@
+dnl #
+dnl # 2.6.34 API change
+dnl # The bdi_setup_and_register() helper function is avilable and
+dnl # exported by the kernel.  This is a trivial helper function but
+dnl # using it significantly simplifies the code surrounding setting
+dnl # up and tearing down the bdi structure.
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_BDI_SETUP_AND_REGISTER], [
+	ZFS_CHECK_SYMBOL_EXPORT(
+		[bdi_setup_and_register],
+		[mm/backing-dev.c],
+		[AC_DEFINE(HAVE_BDI_SETUP_AND_REGISTER, 1,
+		[bdi_setup_and_register() is available])],
+		[])
+])

config/kernel.m4

@@ -41,6 +41,7 @@ AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [
 	ZFS_AC_KERNEL_6ARGS_SECURITY_INODE_INIT_SECURITY
 	ZFS_AC_KERNEL_MOUNT_NODEV
 	ZFS_AC_KERNEL_BDI
+	ZFS_AC_KERNEL_BDI_SETUP_AND_REGISTER
 
 	AS_IF([test "$LINUX_OBJ" != "$LINUX"], [
 		KERNELMAKE_PARAMS="$KERNELMAKE_PARAMS O=$LINUX_OBJ"

configure

@@ -14953,6 +14953,59 @@ fi
 
 
 
+	{ $as_echo "$as_me:$LINENO: checking whether symbol bdi_setup_and_register is exported" >&5
+$as_echo_n "checking whether symbol bdi_setup_and_register is exported... " >&6; }
+	grep -q -E '[[:space:]]bdi_setup_and_register[[:space:]]' \
+		$LINUX_OBJ/$LINUX_SYMBOLS 2>/dev/null
+	rc=$?
+	if test $rc -ne 0; then
+
+		export=0
+		for file in mm/backing-dev.c; do
+			grep -q -E "EXPORT_SYMBOL.*(bdi_setup_and_register)" "$LINUX/$file" 2>/dev/null
+			rc=$?
+			if test $rc -eq 0; then
+
+				export=1
+				break;
+
+fi
+
+		done
+		if test $export -eq 0; then
+
+			{ $as_echo "$as_me:$LINENO: result: no" >&5
+$as_echo "no" >&6; }
+
+
+else
+
+			{ $as_echo "$as_me:$LINENO: result: yes" >&5
+$as_echo "yes" >&6; }
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_BDI_SETUP_AND_REGISTER 1
+_ACEOF
+
+
+fi
+
+
+else
+
+		{ $as_echo "$as_me:$LINENO: result: yes" >&5
+$as_echo "yes" >&6; }
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_BDI_SETUP_AND_REGISTER 1
+_ACEOF
+
+
+fi
+
+
+
+
 	if test "$LINUX_OBJ" != "$LINUX"; then
 
 		KERNELMAKE_PARAMS="$KERNELMAKE_PARAMS O=$LINUX_OBJ"
@@ -19509,6 +19562,59 @@ fi
 
 
 
+	{ $as_echo "$as_me:$LINENO: checking whether symbol bdi_setup_and_register is exported" >&5
+$as_echo_n "checking whether symbol bdi_setup_and_register is exported... " >&6; }
+	grep -q -E '[[:space:]]bdi_setup_and_register[[:space:]]' \
+		$LINUX_OBJ/$LINUX_SYMBOLS 2>/dev/null
+	rc=$?
+	if test $rc -ne 0; then
+
+		export=0
+		for file in mm/backing-dev.c; do
+			grep -q -E "EXPORT_SYMBOL.*(bdi_setup_and_register)" "$LINUX/$file" 2>/dev/null
+			rc=$?
+			if test $rc -eq 0; then
+
+				export=1
+				break;
+
+fi
+
+		done
+		if test $export -eq 0; then
+
+			{ $as_echo "$as_me:$LINENO: result: no" >&5
+$as_echo "no" >&6; }
+
+
+else
+
+			{ $as_echo "$as_me:$LINENO: result: yes" >&5
+$as_echo "yes" >&6; }
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_BDI_SETUP_AND_REGISTER 1
+_ACEOF
+
+
+fi
+
+
+else
+
+		{ $as_echo "$as_me:$LINENO: result: yes" >&5
+$as_echo "yes" >&6; }
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_BDI_SETUP_AND_REGISTER 1
+_ACEOF
+
+
+fi
+
+
+
+
 	if test "$LINUX_OBJ" != "$LINUX"; then
 
 		KERNELMAKE_PARAMS="$KERNELMAKE_PARAMS O=$LINUX_OBJ"

dracut/90zfs/Makefile.in

@@ -42,6 +42,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

dracut/Makefile.in

@@ -41,6 +41,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

etc/Makefile.in

@@ -41,6 +41,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

etc/init.d/Makefile.in

@@ -42,6 +42,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

etc/zfs/Makefile.in

@@ -42,6 +42,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

include/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

include/linux/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

include/linux/vfs_compat.h

@@ -62,23 +62,36 @@ truncate_setsize(struct inode *ip, loff_t new)
 }
 #endif /* HAVE_TRUNCATE_SETSIZE */
 
+#if defined(HAVE_BDI) && !defined(HAVE_BDI_SETUP_AND_REGISTER)
 /*
- * 2.6.32 API change,
+ * 2.6.34 API change,
- * Added backing_device_info (bdi) per super block interfaces.  When
+ * Add bdi_setup_and_register() function if not yet provided by kernel.
- * available a bdi must be configured when using a non-device backed
+ * It is used to quickly initialize and register a BDI for the filesystem.
- * filesystem for proper writeback.  It's safe to leave this code
- * dormant for kernels which only support pdflush and not bdi.
  */
-#ifdef HAVE_BDI
+extern atomic_long_t zfs_bdi_seq;
-#define	bdi_get_sb(sb)				(sb->s_bdi)
+
-#define	bdi_put_sb(sb, bdi)			(sb->s_bdi = bdi)
+static inline int
-#else
+bdi_setup_and_register(struct backing_dev_info *bdi,char *name,unsigned int cap)
-#define	bdi_init(bdi)				(0)
+{
-#define	bdi_destroy(bdi)			(0)
+	char tmp[32];
-#define	bdi_register(bdi, parent, fmt, args)	(0)
+	int error;
-#define	bdi_unregister(bdi)			(0)
+
-#define	bdi_get_sb(sb)				(0)
+	bdi->name = name;
-#define	bdi_put_sb(sb, bdi)			(0)
+	bdi->capabilities = cap;
-#endif /* HAVE_BDI */
+	error = bdi_init(bdi);
+	if (error)
+		return (error);
+
+	sprintf(tmp, "%.28s%s", name, "-%d");
+	error = bdi_register(bdi, NULL, tmp,
+	    atomic_long_inc_return(&zfs_bdi_seq));
+	if (error) {
+		bdi_destroy(bdi);
+		return (error);
+	}
+
+	return (error);
+}
+#endif /* HAVE_BDI && !HAVE_BDI_SETUP_AND_REGISTER */
 
 #endif /* _ZFS_VFS_H */

include/sys/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

include/sys/fm/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

include/sys/fm/fs/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

include/sys/fs/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/Makefile.in

@@ -41,6 +41,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libavl/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libefi/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libnvpair/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libshare/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libspl/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libspl/asm-generic/Makefile.in

@@ -42,6 +42,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libspl/asm-i386/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libspl/asm-x86_64/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libspl/include/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libspl/include/ia32/Makefile.in

@@ -41,6 +41,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libspl/include/ia32/sys/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libspl/include/rpc/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libspl/include/sys/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libspl/include/sys/dktp/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libspl/include/sys/sysevent/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libspl/include/util/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libunicode/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libuutil/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libzfs/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

lib/libzpool/Makefile.in

@@ -43,6 +43,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

man/Makefile.in

@@ -41,6 +41,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

man/man8/Makefile.in

@@ -41,6 +41,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

module/zfs/zfs_vfsops.c

@@ -600,12 +600,6 @@ zfs_sb_create(const char *osname, zfs_sb_t **zsbp)
 	zsb->z_show_ctldir = ZFS_SNAPDIR_VISIBLE;
 	zsb->z_os = os;
 
-	error = -bdi_init(&zsb->z_bdi);
-	if (error) {
-		kmem_free(zsb, sizeof (zfs_sb_t));
-		return (error);
-	}
-
 	error = zfs_get_zplprop(os, ZFS_PROP_VERSION, &zsb->z_version);
 	if (error) {
 		goto out;
@@ -807,7 +801,6 @@ zfs_sb_free(zfs_sb_t *zsb)
 
 	zfs_fuid_destroy(zsb);
 
-	bdi_destroy(&zsb->z_bdi);
 	mutex_destroy(&zsb->z_znodes_lock);
 	mutex_destroy(&zsb->z_lock);
 	list_destroy(&zsb->z_all_znodes);
@@ -1089,9 +1082,9 @@ zfs_sb_teardown(zfs_sb_t *zsb, boolean_t unmounting)
 }
 EXPORT_SYMBOL(zfs_sb_teardown);
 
-#ifdef HAVE_BDI
+#if defined(HAVE_BDI) && !defined(HAVE_BDI_SETUP_AND_REGISTER)
-static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);
+atomic_long_t zfs_bdi_seq = ATOMIC_LONG_INIT(0);
-#endif /* HAVE_BDI */
+#endif /* HAVE_BDI && !HAVE_BDI_SETUP_AND_REGISTER */
 
 int
 zfs_domount(struct super_block *sb, void *data, int silent)
@@ -1118,7 +1111,23 @@ zfs_domount(struct super_block *sb, void *data, int silent)
 	sb->s_time_gran = 1;
 	sb->s_blocksize = recordsize;
 	sb->s_blocksize_bits = ilog2(recordsize);
-	bdi_put_sb(sb, NULL);
+
+#ifdef HAVE_BDI
+	/*
+	 * 2.6.32 API change,
+	 * Added backing_device_info (BDI) per super block interfaces.  A BDI
+	 * must be configured when using a non-device backed filesystem for
+	 * proper writeback.  This is not required for older pdflush kernels.
+	 *
+	 * NOTE: Linux read-ahead is disabled in favor of zfs read-ahead.
+	 */
+	zsb->z_bdi.ra_pages = 0;
+	sb->s_bdi = &zsb->z_bdi;
+
+	error = -bdi_setup_and_register(&zsb->z_bdi, "zfs", BDI_CAP_MAP_COPY);
+	if (error)
+		goto out;
+#endif /* HAVE_BDI */
 
 	/* Set callback operations for the file system. */
 	sb->s_op = &zpl_super_operations;
@@ -1143,16 +1152,6 @@ zfs_domount(struct super_block *sb, void *data, int silent)
 		dmu_objset_set_user(zsb->z_os, zsb);
 		mutex_exit(&zsb->z_os->os_user_ptr_lock);
 	} else {
-		/* Disable Linux read-ahead handled by lower layers */
-		zsb->z_bdi.ra_pages = 0;
-
-		error = -bdi_register(&zsb->z_bdi, NULL, "zfs-%d",
-		    atomic_long_inc_return(&bdi_seq));
-		if (error)
-			goto out;
-
-		bdi_put_sb(sb, &zsb->z_bdi);
-
 		error = zfs_sb_setup(zsb, B_TRUE);
 #ifdef HAVE_SNAPSHOT
 		(void) zfs_snap_create(zsb);
@@ -1193,10 +1192,9 @@ zfs_umount(struct super_block *sb)
 	VERIFY(zfs_sb_teardown(zsb, B_TRUE) == 0);
 	os = zsb->z_os;
 
-	if (bdi_get_sb(sb)) {
+#ifdef HAVE_BDI
-		bdi_unregister(bdi_get_sb(sb));
+	bdi_destroy(sb->s_bdi);
-		bdi_put_sb(sb, NULL);
+#endif /* HAVE_BDI */
-	}
 
 	/*
 	 * z_os will be NULL if there was an error in

scripts/Makefile.in

@@ -42,6 +42,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

scripts/zpios-profile/Makefile.in

@@ -42,6 +42,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

scripts/zpios-test/Makefile.in

@@ -42,6 +42,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

scripts/zpool-config/Makefile.in

@@ -42,6 +42,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

scripts/zpool-layout/Makefile.in

@@ -42,6 +42,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

udev/Makefile.in

@@ -41,6 +41,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

udev/rules.d/Makefile.in

@@ -42,6 +42,7 @@ am__aclocal_m4_deps =  \
 	$(top_srcdir)/config/always-no-unused-but-set-variable.m4 \
 	$(top_srcdir)/config/kernel-bdev-block-device-operations.m4 \
 	$(top_srcdir)/config/kernel-bdev-logical-size.m4 \
+	$(top_srcdir)/config/kernel-bdi-setup-and-register.m4 \
 	$(top_srcdir)/config/kernel-bdi.m4 \
 	$(top_srcdir)/config/kernel-bio-empty-barrier.m4 \
 	$(top_srcdir)/config/kernel-bio-end-io-t-args.m4 \

zfs_config.h.in

@@ -21,6 +21,9 @@
 /* struct super_block has s_bdi */
 #undef HAVE_BDI
 
+/* bdi_setup_and_register() is available */
+#undef HAVE_BDI_SETUP_AND_REGISTER
+
 /* bio_empy_barrier() is defined */
 #undef HAVE_BIO_EMPTY_BARRIER