sys-fs/zfs-kmod-0.6.5-r1: Fix discard corruption regression

This is the first data corruption bug in the history of the ZoL project
and I regret to say that it is my fault. I wrote the patch that caused
it and it went into HEAD after passing upstream review. It affects Linux
2.6.36 and later.

Package-Manager: portage-2.2.20.1
Signed-off-by: Richard Yao <ryao@gentoo.org>

2 files changed, 185 insertions, 0 deletions

diff --git a/sys-fs/zfs-kmod/files/zfs-kmod-0.6.5-discard-on-zvol-fix.patch b/sys-fs/zfs-kmod/files/zfs-kmod-0.6.5-discard-on-zvol-fix.patch
new file mode 100644
index 000000000000..632d08d28e1f
--- /dev/null
+++ b/sys-fs/zfs-kmod/files/zfs-kmod-0.6.5-discard-on-zvol-fix.patch
@@ -0,0 +1,31 @@
+From 96165264ad0afe7a5d440ef49f9712a188486266 Mon Sep 17 00:00:00 2001
+From: Richard Yao <ryao@gentoo.org>
+Date: Fri, 18 Sep 2015 08:32:52 -0400
+Subject: [PATCH] Discard on zvols should not exceed the length of a block
+
+37f9dac592bf5889c3efb305c48ac39b4c7dd140 replaced the end-start
+calculation with a cached value, but neglected to update it on discard
+operations. This can cause us to discard data not requested, causing
+data loss on zvols.
+
+Reported-by: Richard Connon <richard.connon@zynstra.com>
+Signed-off-by: Richard Yao <ryao@gentoo.org>
+---
+ module/zfs/zvol.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/module/zfs/zvol.c b/module/zfs/zvol.c
+index 492f8ff..c5a8071 100644
+--- a/module/zfs/zvol.c
++++ b/module/zfs/zvol.c
+@@ -661,6 +661,7 @@ zvol_discard(struct bio *bio)
+ 	if (!(bio->bi_rw & REQ_SECURE)) {
+ 		start = P2ROUNDUP(start, zv->zv_volblocksize);
+ 		end = P2ALIGN(end, zv->zv_volblocksize);
++		size = end - start;
+ 	}
+ #endif
+ 
+-- 
+2.4.6
+
diff --git a/sys-fs/zfs-kmod/zfs-kmod-0.6.5-r1.ebuild b/sys-fs/zfs-kmod/zfs-kmod-0.6.5-r1.ebuild
new file mode 100644
index 000000000000..0e3665f95f84
--- /dev/null
+++ b/sys-fs/zfs-kmod/zfs-kmod-0.6.5-r1.ebuild
@@ -0,0 +1,154 @@
+# Copyright 1999-2015 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+# $Id$
+
+EAPI="4"
+
+AT_M4DIR="config"
+AUTOTOOLS_AUTORECONF="1"
+AUTOTOOLS_IN_SOURCE_BUILD="1"
+
+inherit flag-o-matic linux-info linux-mod toolchain-funcs autotools-utils
+
+if [ ${PV} == "9999" ] ; then
+	inherit git-2
+	EGIT_REPO_URI="https://github.com/zfsonlinux/zfs.git"
+else
+	inherit eutils versionator
+	SRC_URI="https://github.com/zfsonlinux/zfs/archive/zfs-${PV}.tar.gz"
+	S="${WORKDIR}/zfs-zfs-${PV}"
+	KEYWORDS="~amd64 ~arm ~ppc ~ppc64"
+fi
+
+DESCRIPTION="Linux ZFS kernel module for sys-fs/zfs"
+HOMEPAGE="http://zfsonlinux.org/"
+
+LICENSE="CDDL debug? ( GPL-2+ )"
+SLOT="0"
+IUSE="custom-cflags debug +rootfs"
+RESTRICT="debug? ( strip ) test"
+
+DEPEND="
+	=sys-kernel/spl-${PV}*
+	dev-lang/perl
+	virtual/awk
+"
+
+RDEPEND="${DEPEND}
+	!sys-fs/zfs-fuse
+"
+
+pkg_setup() {
+	linux-info_pkg_setup
+	CONFIG_CHECK="!DEBUG_LOCK_ALLOC
+		BLK_DEV_LOOP
+		EFI_PARTITION
+		IOSCHED_NOOP
+		MODULES
+		!PAX_KERNEXEC_PLUGIN_METHOD_OR
+		!PAX_USERCOPY_SLABS
+		ZLIB_DEFLATE
+		ZLIB_INFLATE
+	"
+
+	use debug && CONFIG_CHECK="${CONFIG_CHECK}
+		FRAME_POINTER
+		DEBUG_INFO
+		!DEBUG_INFO_REDUCED
+	"
+
+	use rootfs && \
+		CONFIG_CHECK="${CONFIG_CHECK}
+			BLK_DEV_INITRD
+			DEVTMPFS
+	"
+
+	kernel_is ge 2 6 32 || die "Linux 2.6.32 or newer required"
+
+	[ ${PV} != "9999" ] && \
+		{ kernel_is le 4 2 || die "Linux 4.2 is the latest supported version."; }
+
+	check_extra_config
+}
+
+src_prepare() {
+	if [ ${PV} != "9999" ]
+	then
+		# Fix zvol data loss regression
+		# https://github.com/zfsonlinux/zfs/pull/3798
+		epatch "${FILESDIR}/${P}-discard-on-zvol-fix.patch"
+	fi
+
+	# Remove GPLv2-licensed ZPIOS unless we are debugging
+	use debug || sed -e 's/^subdir-m += zpios$//' -i "${S}/module/Makefile.in"
+
+	# Set module revision number
+	[ ${PV} != "9999" ] && \
+		{ sed -i "s/\(Release:\)\(.*\)1/\1\2${PR}-gentoo/" "${S}/META" || die "Could not set Gentoo release"; }
+
+	autotools-utils_src_prepare
+}
+
+src_configure() {
+	local SPL_PATH="$(basename $(echo "${EROOT}usr/src/spl-"*))"
+	use custom-cflags || strip-flags
+	filter-ldflags -Wl,*
+
+	set_arch_to_kernel
+	local myeconfargs=(${myeconfargs}
+		--bindir="${EPREFIX}/bin"
+		--sbindir="${EPREFIX}/sbin"
+		--with-config=kernel
+		--with-linux="${KV_DIR}"
+		--with-linux-obj="${KV_OUT_DIR}"
+		--with-spl="${EROOT}usr/src/${SPL_PATH}"
+		--with-spl-obj="${EROOT}usr/src/${SPL_PATH}/${KV_FULL}"
+		$(use_enable debug)
+	)
+
+	autotools-utils_src_configure
+}
+
+src_install() {
+	autotools-utils_src_install INSTALL_MOD_PATH="${INSTALL_MOD_PATH:-$EROOT}"
+	dodoc AUTHORS COPYRIGHT DISCLAIMER README.markdown
+}
+
+pkg_postinst() {
+	linux-mod_pkg_postinst
+
+	# Remove old modules
+	if [ -d "${EROOT}lib/modules/${KV_FULL}/addon/zfs" ]
+	then
+		ewarn "${PN} now installs modules in ${EROOT}lib/modules/${KV_FULL}/extra/zfs"
+		ewarn "Old modules were detected in ${EROOT}lib/modules/${KV_FULL}/addon/zfs"
+		ewarn "Automatically removing old modules to avoid problems."
+		rm -r "${EROOT}lib/modules/${KV_FULL}/addon/zfs" || die "Cannot remove modules"
+		rmdir --ignore-fail-on-non-empty "${EROOT}lib/modules/${KV_FULL}/addon"
+	fi
+
+	if use x86 || use arm
+	then
+		ewarn "32-bit kernels will likely require increasing vmalloc to"
+		ewarn "at least 256M and decreasing zfs_arc_max to some value less than that."
+	fi
+
+	ewarn "This version of ZFSOnLinux includes support for new feature flags"
+	ewarn "that are incompatible with previous versions. GRUB2 support for"
+	ewarn "/boot with the new feature flags is not yet available."
+	ewarn "Do *NOT* upgrade root pools to use the new feature flags."
+	ewarn "Any new pools will be created with the new feature flags by default"
+	ewarn "and will not be compatible with older versions of ZFSOnLinux. To"
+	ewarn "create a newpool that is backward compatible wih GRUB2, use "
+	ewarn
+	ewarn "zpool create -d -o feature@async_destroy=enabled "
+	ewarn "	-o feature@empty_bpobj=enabled -o feature@lz4_compress=enabled"
+	ewarn "	-o feature@spacemap_histogram=enabled"
+	ewarn "	-o feature@enabled_txg=enabled "
+	ewarn "	-o feature@extensible_dataset=enabled -o feature@bookmarks=enabled"
+	ewarn "	..."
+	ewarn
+	ewarn "GRUB2 support will be updated as soon as either the GRUB2"
+	ewarn "developers do a tag or the Gentoo developers find time to backport"
+	ewarn "support from GRUB2 HEAD."
+}