diff --git a/pkgs/os-specific/linux/zfs/bc151f7b312dea09c6ec5b9a320e65140789643a.patch b/pkgs/os-specific/linux/zfs/bc151f7b312dea09c6ec5b9a320e65140789643a.patch
deleted file mode 100644
index 382c8ce63eea..000000000000
--- a/pkgs/os-specific/linux/zfs/bc151f7b312dea09c6ec5b9a320e65140789643a.patch
+++ /dev/null
@@ -1,84 +0,0 @@
-From bc151f7b312dea09c6ec5b9a320e65140789643a Mon Sep 17 00:00:00 2001
-From: Ned Bass <bass6@llnl.gov>
-Date: Thu, 16 Oct 2014 13:52:56 -0700
-Subject: [PATCH] Remove checks for mandatory locks
-
-The Linux VFS handles mandatory locks generically so we shouldn't
-need to check for conflicting locks in zfs_read(), zfs_write(), or
-zfs_freesp().  Linux 3.18 removed the lock_may_read() and
-lock_may_write() interfaces which we were relying on for this
-purpose.  Rather than emulating those interfaces we remove the
-redundant checks.
-
-Signed-off-by: Ned Bass <bass6@llnl.gov>
-Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
-Closes #2804
----
- module/zfs/zfs_vnops.c | 18 ------------------
- module/zfs/zfs_znode.c | 10 ----------
- 2 files changed, 28 deletions(-)
-
-diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c
-index 33f9e0e..2f55e56 100644
---- a/module/zfs/zfs_vnops.c
-+++ b/module/zfs/zfs_vnops.c
-@@ -474,15 +474,6 @@ zfs_read(struct inode *ip, uio_t *uio, int ioflag, cred_t *cr)
- 	}
- 
- 	/*
--	 * Check for mandatory locks
--	 */
--	if (mandatory_lock(ip) &&
--	    !lock_may_read(ip, uio->uio_loffset, uio->uio_resid)) {
--		ZFS_EXIT(zsb);
--		return (SET_ERROR(EAGAIN));
--	}
--
--	/*
- 	 * If we're in FRSYNC mode, sync out this znode before reading it.
- 	 */
- 	if (ioflag & FRSYNC || zsb->z_os->os_sync == ZFS_SYNC_ALWAYS)
-@@ -651,15 +642,6 @@ zfs_write(struct inode *ip, uio_t *uio, int ioflag, cred_t *cr)
- 	}
- 
- 	/*
--	 * Check for mandatory locks before calling zfs_range_lock()
--	 * in order to prevent a deadlock with locks set via fcntl().
--	 */
--	if (mandatory_lock(ip) && !lock_may_write(ip, woff, n)) {
--		ZFS_EXIT(zsb);
--		return (SET_ERROR(EAGAIN));
--	}
--
--	/*
- 	 * Pre-fault the pages to ensure slow (eg NFS) pages
- 	 * don't hold up txg.
- 	 * Skip this if uio contains loaned arc_buf.
-diff --git a/module/zfs/zfs_znode.c b/module/zfs/zfs_znode.c
-index 90dbfd3..f02c021 100644
---- a/module/zfs/zfs_znode.c
-+++ b/module/zfs/zfs_znode.c
-@@ -1546,7 +1546,6 @@ zfs_trunc(znode_t *zp, uint64_t end)
- int
- zfs_freesp(znode_t *zp, uint64_t off, uint64_t len, int flag, boolean_t log)
- {
--	struct inode *ip = ZTOI(zp);
- 	dmu_tx_t *tx;
- 	zfs_sb_t *zsb = ZTOZSB(zp);
- 	zilog_t *zilog = zsb->z_log;
-@@ -1567,15 +1566,6 @@ zfs_freesp(znode_t *zp, uint64_t off, uint64_t len, int flag, boolean_t log)
- 		goto out;
- 	}
- 
--	/*
--	 * Check for any locks in the region to be freed.
--	 */
--	if (ip->i_flock && mandatory_lock(ip)) {
--		uint64_t length = (len ? len : zp->z_size - off);
--		if (!lock_may_write(ip, off, length))
--			return (SET_ERROR(EAGAIN));
--	}
--
- 	if (len == 0) {
- 		error = zfs_trunc(zp, off);
- 	} else {
diff --git a/pkgs/os-specific/linux/zfs/default.nix b/pkgs/os-specific/linux/zfs/default.nix
index 3661137fc295..a893154b9365 100644
--- a/pkgs/os-specific/linux/zfs/default.nix
+++ b/pkgs/os-specific/linux/zfs/default.nix
@@ -33,6 +33,7 @@ stdenv.mkDerivation rec {
     substituteInPlace ./config/zfs-build.m4       --replace "\$sysconfdir/init.d"     "$out/etc/init.d"
     substituteInPlace ./etc/zfs/Makefile.am       --replace "\$(sysconfdir)"          "$out/etc"
     substituteInPlace ./cmd/zed/Makefile.am       --replace "\$(sysconfdir)"          "$out/etc"
+    substituteInPlace ./module/Makefile.in        --replace "/bin/cp"                 "cp"
 
     ./autogen.sh
   '';
diff --git a/pkgs/os-specific/linux/zfs/git.nix b/pkgs/os-specific/linux/zfs/git.nix
index fde5310deed2..21a580136d56 100644
--- a/pkgs/os-specific/linux/zfs/git.nix
+++ b/pkgs/os-specific/linux/zfs/git.nix
@@ -1,15 +1,17 @@
 { stdenv, fetchgit, kernel, spl_git, perl, autoconf, automake, libtool, zlib, libuuid, coreutils, utillinux }:
 
 stdenv.mkDerivation {
-  name = "zfs-0.6.3-${kernel.version}";
+  name = "zfs-0.6.4-${kernel.version}";
 
   src = fetchgit {
     url = git://github.com/zfsonlinux/zfs.git;
-    rev = "07dabd234dd51a1e5adc5bd21cddf5b5fdc70732";
-    sha256 = "1yqsfdhyzh33aisfvwqd692n5kfgnlz7yjixd2gqn8vx9bv0dz0b";
+    rev = "74328ee18f94d27f9c802d29fdd311018dab2adf";
+    sha256 = "0ayyqbb2crki1xvibfmscav5j7g0z77ys83dx10430ljamvylwb0";
   };
 
-  patches = [ ./mount_zfs_prefix.patch ./nix-build.patch ./bc151f7b312dea09c6ec5b9a320e65140789643a.patch ];
+  patches = [
+    ./nix-build-git.patch
+  ];
 
   buildInputs = [ spl_git perl autoconf automake libtool zlib libuuid coreutils ];
 
@@ -28,6 +30,7 @@ stdenv.mkDerivation {
     substituteInPlace ./config/zfs-build.m4       --replace "\$sysconfdir/init.d"     "$out/etc/init.d"
     substituteInPlace ./etc/zfs/Makefile.am       --replace "\$(sysconfdir)"          "$out/etc"
     substituteInPlace ./cmd/zed/Makefile.am       --replace "\$(sysconfdir)"          "$out/etc"
+    substituteInPlace ./module/Makefile.in        --replace "/bin/cp"                 "cp"
 
     ./autogen.sh
   '';
@@ -41,6 +44,7 @@ stdenv.mkDerivation {
     "--with-udevdir=$(out)/lib/udev"
     "--with-systemdunitdir=$(out)/etc/systemd/system"
     "--with-systemdpresetdir=$(out)/etc/systemd/system-preset"
+    "--with-mounthelperdir=$(out)/sbin"
     "--sysconfdir=/etc"
     "--localstatedir=/var"
   ];
diff --git a/pkgs/os-specific/linux/zfs/nix-build-git.patch b/pkgs/os-specific/linux/zfs/nix-build-git.patch
new file mode 100644
index 000000000000..ae8e82f703af
--- /dev/null
+++ b/pkgs/os-specific/linux/zfs/nix-build-git.patch
@@ -0,0 +1,133 @@
+diff --git a/Makefile.am b/Makefile.am
+index 49b417a..f4af44d 100644
+--- a/Makefile.am
++++ b/Makefile.am
+@@ -12,10 +12,10 @@ endif
+ if CONFIG_KERNEL
+ SUBDIRS += module
+ 
+-extradir = @prefix@/src/zfs-$(VERSION)
++extradir = @prefix@/libexec/zfs-$(VERSION)
+ extra_HEADERS = zfs.release.in zfs_config.h.in
+ 
+-kerneldir = @prefix@/src/zfs-$(VERSION)/$(LINUX_VERSION)
++kerneldir = @prefix@/zfs-$(VERSION)/$(LINUX_VERSION)
+ nodist_kernel_HEADERS = zfs.release zfs_config.h module/$(LINUX_SYMBOLS)
+ endif
+ 
+diff --git a/include/Makefile.am b/include/Makefile.am
+index a94cad5..a160fe2 100644
+--- a/include/Makefile.am
++++ b/include/Makefile.am
+@@ -29,6 +29,6 @@ libzfs_HEADERS = $(COMMON_H) $(USER_H)
+ endif
+ 
+ if CONFIG_KERNEL
+-kerneldir = @prefix@/src/zfs-$(VERSION)/include
++kerneldir = @prefix@/include
+ kernel_HEADERS = $(COMMON_H) $(KERNEL_H)
+ endif
+diff --git a/include/linux/Makefile.am b/include/linux/Makefile.am
+index d00b1c8..3242d2e 100644
+--- a/include/linux/Makefile.am
++++ b/include/linux/Makefile.am
+@@ -17,6 +17,6 @@ libzfs_HEADERS = $(COMMON_H) $(USER_H)
+ endif
+ 
+ if CONFIG_KERNEL
+-kerneldir = @prefix@/src/zfs-$(VERSION)/include/linux
++kerneldir = @prefix@/include/linux
+ kernel_HEADERS = $(COMMON_H) $(KERNEL_H)
+ endif
+diff --git a/include/sys/Makefile.am b/include/sys/Makefile.am
+index 7ddace0..8da3870 100644
+--- a/include/sys/Makefile.am
++++ b/include/sys/Makefile.am
+@@ -102,6 +102,6 @@ libzfs_HEADERS = $(COMMON_H) $(USER_H)
+ endif
+ 
+ if CONFIG_KERNEL
+-kerneldir = @prefix@/src/zfs-$(VERSION)/include/sys
++kerneldir = @prefix@/include/sys
+ kernel_HEADERS = $(COMMON_H) $(KERNEL_H)
+ endif
+diff --git a/include/sys/fm/Makefile.am b/include/sys/fm/Makefile.am
+index 8bca5d8..a5eafcd 100644
+--- a/include/sys/fm/Makefile.am
++++ b/include/sys/fm/Makefile.am
+@@ -16,6 +16,6 @@ libzfs_HEADERS = $(COMMON_H) $(USER_H)
+ endif
+ 
+ if CONFIG_KERNEL
+-kerneldir = @prefix@/src/zfs-$(VERSION)/include/sys/fm
++kerneldir = @prefix@/include/sys/fm
+ kernel_HEADERS = $(COMMON_H) $(KERNEL_H)
+ endif
+diff --git a/include/sys/fm/fs/Makefile.am b/include/sys/fm/fs/Makefile.am
+index fdc9eb5..807c47c 100644
+--- a/include/sys/fm/fs/Makefile.am
++++ b/include/sys/fm/fs/Makefile.am
+@@ -13,6 +13,6 @@ libzfs_HEADERS = $(COMMON_H) $(USER_H)
+ endif
+ 
+ if CONFIG_KERNEL
+-kerneldir = @prefix@/src/zfs-$(VERSION)/include/sys/fm/fs
++kerneldir = @prefix@/include/sys/fm/fs
+ kernel_HEADERS = $(COMMON_H) $(KERNEL_H)
+ endif
+diff --git a/include/sys/fs/Makefile.am b/include/sys/fs/Makefile.am
+index 0859b9f..b0c6eec 100644
+--- a/include/sys/fs/Makefile.am
++++ b/include/sys/fs/Makefile.am
+@@ -13,6 +13,6 @@ libzfs_HEADERS = $(COMMON_H) $(USER_H)
+ endif
+ 
+ if CONFIG_KERNEL
+-kerneldir = @prefix@/src/zfs-$(VERSION)/include/sys/fs
++kerneldir = @prefix@/include/sys/fs
+ kernel_HEADERS = $(COMMON_H) $(KERNEL_H)
+ endif
+diff --git a/module/Makefile.in b/module/Makefile.in
+index 686402b..9cbf598 100644
+--- a/module/Makefile.in
++++ b/module/Makefile.in
+@@ -18,9 +18,9 @@ modules:
+ 	@# installed devel headers, or they may be in the module
+ 	@# subdirectory when building against the spl source tree.
+ 	@if [ -f @SPL_OBJ@/@SPL_SYMBOLS@ ]; then \
+-		/bin/cp @SPL_OBJ@/@SPL_SYMBOLS@ .; \
++		cp @SPL_OBJ@/@SPL_SYMBOLS@ .; \
+ 	elif [ -f @SPL_OBJ@/module/@SPL_SYMBOLS@ ]; then \
+-		/bin/cp @SPL_OBJ@/module/@SPL_SYMBOLS@ .; \
++		cp @SPL_OBJ@/module/@SPL_SYMBOLS@ .; \
+ 	else \
+ 		echo -e "\n" \
+ 		"*** Missing spl symbols ensure you have built the spl:\n" \
+@@ -28,6 +28,8 @@ modules:
+ 		"*** - @SPL_OBJ@/module/@SPL_SYMBOLS@\n"; \
+ 		exit 1; \
+ 	fi
++	@# when copying a file out of the nix store, we need to make it writable again. 
++	chmod +w @SPL_SYMBOLS@
+ 	$(MAKE) -C @LINUX_OBJ@ SUBDIRS=`pwd` @KERNELMAKE_PARAMS@ CONFIG_ZFS=m $@
+ 
+ clean:
+@@ -42,15 +44,15 @@ clean:
+ modules_install:
+ 	@# Install the kernel modules
+ 	$(MAKE) -C @LINUX_OBJ@ SUBDIRS=`pwd` $@ \
+-		INSTALL_MOD_PATH=$(DESTDIR)$(INSTALL_MOD_PATH) \
++		INSTALL_MOD_PATH=@prefix@/$(INSTALL_MOD_PATH) \
+ 		INSTALL_MOD_DIR=$(INSTALL_MOD_DIR) \
+ 		KERNELRELEASE=@LINUX_VERSION@
+ 	@# Remove extraneous build products when packaging
+-	kmoddir=$(DESTDIR)$(INSTALL_MOD_PATH)/lib/modules/@LINUX_VERSION@; \
++	kmoddir=@prefix@/$(INSTALL_MOD_PATH)/lib/modules/@LINUX_VERSION@; \
+ 	if [ -n $$kmoddir ]; then \
+ 		find $$kmoddir -name 'modules.*' | xargs $(RM); \
+ 	fi
+-	sysmap=$(DESTDIR)$(INSTALL_MOD_PATH)/boot/System.map-@LINUX_VERSION@; \
++	sysmap=@prefix@/$(INSTALL_MOD_PATH)/boot/System.map-@LINUX_VERSION@; \
+ 	if [ -f $$sysmap ]; then \
+ 		depmod -ae -F $$sysmap @LINUX_VERSION@; \
+ 	fi
diff --git a/pkgs/os-specific/linux/zfs/remove-lock-checks.patch b/pkgs/os-specific/linux/zfs/remove-lock-checks.patch
deleted file mode 100644
index 1261b49ee1d4..000000000000
--- a/pkgs/os-specific/linux/zfs/remove-lock-checks.patch
+++ /dev/null
@@ -1,64 +0,0 @@
-diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c
-index 33f9e0e..2f55e56 100644
---- a/module/zfs/zfs_vnops.c
-+++ b/module/zfs/zfs_vnops.c
-@@ -474,15 +474,6 @@ zfs_read(struct inode *ip, uio_t *uio, int ioflag, cred_t *cr)
- 	}
- 
- 	/*
--	 * Check for mandatory locks
--	 */
--	if (mandatory_lock(ip) &&
--	    !lock_may_read(ip, uio->uio_loffset, uio->uio_resid)) {
--		ZFS_EXIT(zsb);
--		return (SET_ERROR(EAGAIN));
--	}
--
--	/*
- 	 * If we're in FRSYNC mode, sync out this znode before reading it.
- 	 */
- 	if (ioflag & FRSYNC || zsb->z_os->os_sync == ZFS_SYNC_ALWAYS)
-@@ -651,15 +642,6 @@ zfs_write(struct inode *ip, uio_t *uio, int ioflag, cred_t *cr)
- 	}
- 
- 	/*
--	 * Check for mandatory locks before calling zfs_range_lock()
--	 * in order to prevent a deadlock with locks set via fcntl().
--	 */
--	if (mandatory_lock(ip) && !lock_may_write(ip, woff, n)) {
--		ZFS_EXIT(zsb);
--		return (SET_ERROR(EAGAIN));
--	}
--
--	/*
- 	 * Pre-fault the pages to ensure slow (eg NFS) pages
- 	 * don't hold up txg.
- 	 * Skip this if uio contains loaned arc_buf.
-diff --git a/module/zfs/zfs_znode.c b/module/zfs/zfs_znode.c
-index 90dbfd3..f02c021 100644
---- a/module/zfs/zfs_znode.c
-+++ b/module/zfs/zfs_znode.c
-@@ -1546,7 +1546,6 @@ zfs_trunc(znode_t *zp, uint64_t end)
- int
- zfs_freesp(znode_t *zp, uint64_t off, uint64_t len, int flag, boolean_t log)
- {
--	struct inode *ip = ZTOI(zp);
- 	dmu_tx_t *tx;
- 	zfs_sb_t *zsb = ZTOZSB(zp);
- 	zilog_t *zilog = zsb->z_log;
-@@ -1567,15 +1566,6 @@ zfs_freesp(znode_t *zp, uint64_t off, uint64_t len, int flag, boolean_t log)
- 		goto out;
- 	}
- 
--	/*
--	 * Check for any locks in the region to be freed.
--	 */
--	if (ip->i_flock && mandatory_lock(ip)) {
--		uint64_t length = (len ? len : zp->z_size - off);
--		if (!lock_may_write(ip, off, length))
--			return (SET_ERROR(EAGAIN));
--	}
--
- 	if (len == 0) {
- 		error = zfs_trunc(zp, off);
- 	} else {