From 42b01560a92f4bfad494710dd73f162e193a1483 Mon Sep 17 00:00:00 2001
From: Turbo Fredriksson <turbo@bayour.com>
Date: Mon, 6 Jul 2015 00:24:11 +0200
Subject: [PATCH] Add functionality that exists in initramfs to dracut.

* Support 'zfs:<rootfs>' import and mounting.
  This was for some reason removed in eda3d4e1de94cd3a9247bb90a64413a89e736847.
* Support booting from snapshots.
* Support mounting recursive filesystems.
* Support mounting of additional filesystems.
* Support mounting nativly encrypted filesystems.

* Move code snippet that fetches and mounts recursive filesystems into recursive_mount_filesystems().
* zfs_set_ifs() needs to be a global func. We need it in a number of places!
  * Use this wherever we use CMD="somecmd someopt someopt" ; OUT="$($CMD someopt)"
* Dracut have the func emergency_shell() which does a little more.
  For those that don't have it, just run '/bin/sh -i -l'.
---
 contrib/dracut/90zfs/mount-zfs.sh.in  |  45 ++++-
 contrib/dracut/README.dracut.markdown |  25 +++
 contrib/initramfs/scripts/zfs         |   9 +-
 contrib/shell-common/zfs-functions.in | 227 +++++++++++++++++---------
 contrib/shell-common/zfs.in           |   3 +
 5 files changed, 220 insertions(+), 89 deletions(-)

diff --git a/contrib/dracut/90zfs/mount-zfs.sh.in b/contrib/dracut/90zfs/mount-zfs.sh.in
index 4ee3bc300547..634301e8e77b 100755
--- a/contrib/dracut/90zfs/mount-zfs.sh.in
+++ b/contrib/dracut/90zfs/mount-zfs.sh.in
@@ -15,29 +15,58 @@ esac
 udev_trigger
 
 if [ "${root}" = "zfs:AUTO" ] ; then
-	ZFS_BOOTFS=""
 	POOLS=$(get_pools)
 	IFS=";"
+
 	for pool in $POOLS
 	do
 		[ -z "$pool" ] && continue
+		ZFS_BOOTFS=""
 
 		# No 'else' or return below - if there's more pools, we try
 		# them. If not, we'll drop through and go to the end
 		# where we need a reboot because we couldn't find a root fs.
-		if import_pool "$pool"; then
-			if find_rootfs "$pool"; then
-				if mount_fs "${ZFS_BOOTFS}"; then
-					info "ZFS: Using ${ZFS_BOOTFS} as root."
-
-					rootok=1
+		if zfs_action "Importing pool ${pool}" import_pool "${pool}"
+		then
+			if find_rootfs "${pool}"; then
+				if recursive_mount_filesystems \
+				    "Using '${ZFS_BOOTFS}' as root." \
+				    "${ZFS_BOOTFS}"
+				then
 					IFS="$OLD_IFS"
-
+					rootok=1
 					return 0
 				fi
 			fi
 		fi
 	done
+else
+	# Because of the case at the top, it's either 'zfs:AUTO' or
+	# 'zfs:<rootfs>'. Import the pool from rootfs and mount it.
+	root="${root#zfs:}"	# Remove leading 'zfs:'
+	pool="${root%%/*}"	# Remove everything after first slash.
+	ZFS_BOOTFS="${root}"	# For zfs-functions.
+	if zfs_action "Importing pool ${pool}" import_pool "${pool}"; then
+		info "ZFS: Using ${pool} as root pool."
+
+		# Will be overwritten in clone_snap() if we're booting from
+		# a snapshot.
+		ZFS_BOOTFS_ORIG="$ZFS_BOOTFS"
+
+		# Booting from a snapshot? Updates ZFS_BOOTFS_ORIG and ZFS_BOOTFS...
+		echo "${root}" | grep -q '@' && setup_snapshot_booting
+		root="$ZFS_BOOTFS"
+
+		if recursive_mount_filesystems "Using '${root}' as root." \
+		    "${root}"
+		then
+			rootok=1
+			return 0
+		fi
+	else
+		warn "ZFS: Can't import '${pool}'."
+		# Fallthrough
+	fi
 fi
 
 rootok=0
diff --git a/contrib/dracut/README.dracut.markdown b/contrib/dracut/README.dracut.markdown
index d7b4f76adb86..a6593257ce9a 100644
--- a/contrib/dracut/README.dracut.markdown
+++ b/contrib/dracut/README.dracut.markdown
@@ -42,6 +42,31 @@ parameters passed in from the boot loader:
 * `root=...`: If not set, importable pools are searched for a bootfs
 attribute.  If an explicitly set root is desired, you may use
 `root=ZFS:pool/dataset`
+  * It is also possible to boot from a snapshot (technically, a clone of
+    the snapshot) using `root=ZFS:pool/dataset@snapshot`.
+  * If the actual snapshot isn't specified, only the at (@) character,
+    the user will be asked for a snapshot to boot from.
+  * With the extra parameter `rollback=(on,yes,1)`, instead of doing a
+    clone and boot from that, the code will rollback the filesystem up
+    to the snapshot specified.
+  * Even though there is no freely availible native encryption for any
+    opensource ZFS implementation, the hope is that one day have one.
+    This code supports the native encryption that Solaris have, using
+    the `zfs key` option.
+  * Supports both 'native' and 'legacy' filesystems.
+  * Supports 'recursive filesystems'. That is, if the root file system
+    is something like `rpool/ROOT/fedora17`, it is possible to have
+    `rpool/ROOT/fedora17/var`, `rpool/ROOT/fedora17/usr` etc.
+    It is not important that the 'mountpoint' property is set or correct,
+    the 'base filesystem' will be removed from the full path of the filesystem.
+    This means, that with the root fs as `rpool/ROOT/fedora17` and the sub-
+    filesystem as `rpool/ROOT/fedora17/var`, the result would be `/var`,
+    where it will be mounted.
+  * In addition to 'recursive filesystems', it is possible to have other
+    filesystems mounted by setting the ZFS_INITRD_ADDITIONAL_DATASETS variable
+    in /etc/sysconfig/zfs. Here, it is imparative that the 'mountpoint'
+    property is correct for each of these filesystems, since each filesystem
+    will use this to correctly mount it.
 
 * `zfs_force=0`: If set to 1, the initramfs will run `zpool import -f` when
 attempting to import pools if the required pool isn't automatically imported
diff --git a/contrib/initramfs/scripts/zfs b/contrib/initramfs/scripts/zfs
index 1bb23277e67e..0755392eb945 100644
--- a/contrib/initramfs/scripts/zfs
+++ b/contrib/initramfs/scripts/zfs
@@ -335,13 +335,8 @@ mountroot()
 	#   NOTE: Mounted in the order specified in the
 	#         ZFS_INITRD_ADDITIONAL_DATASETS variable so take care!
 
-	# Go through the complete list (recursivly) of all filesystems below
-	# the real root dataset
-	filesystems=$("${ZFS}" list -oname -tfilesystem -H -r "${ZFS_BOOTFS}")
-	for fs in $filesystems $ZFS_INITRD_ADDITIONAL_DATASETS
-	do
-		mount_fs "$fs"
-	done
+	recursive_mount_filesystems "Using ${ZFS_BOOTFS} as root." \
+	    "${ZFS_BOOTFS}"
 
 	# ------------
 	# Debugging information
diff --git a/contrib/shell-common/zfs-functions.in b/contrib/shell-common/zfs-functions.in
index 529ae5bff5bc..23e32875f671 100644
--- a/contrib/shell-common/zfs-functions.in
+++ b/contrib/shell-common/zfs-functions.in
@@ -41,17 +41,6 @@ if type log_failure_msg > /dev/null 2>&1 ; then
 	zfs_log_progress_msg() { log_progress_msg "$1"; }
 elif type success > /dev/null 2>&1 ; then
 	# Fedora/RedHat functions
-	zfs_set_ifs() {
-		# For some reason, the init function library have a problem
-		# with a changed IFS, so this function goes around that.
-		local tIFS="$1"
-		if [ -n "$tIFS" ]
-		then
-			TMP_IFS="$IFS"
-			IFS="$tIFS"
-		fi
-	}
-
 	zfs_log_begin_msg() { echo -n "$1 "; }
 	zfs_log_end_msg() {
 		zfs_set_ifs "$OLD_IFS"
@@ -334,6 +323,35 @@ check_module_loaded()
 	[ -r /sys/module/zfs/version ] && return 0 || return 1
 }
 
+# Recursivly mount all filesystems, including any additional filesystems,
+# below the specified filesystem.
+recursive_mount_filesystems()
+{
+	local msg="$1"
+	local fs="$2"
+	local filesystems f
+
+	# Only fail here if the first fs fails to mount.
+	if zfs_action "$msg" mount_fs "${fs}"; then
+		# Go through the complete list (recursivly) of all filesystems
+		# below the first (root) dataset.
+		filesystems=$("${ZFS}" list -oname -tfilesystem -H -r "${fs}")
+		for f in $filesystems $ZFS_INITRD_ADDITIONAL_DATASETS
+		do
+			# Ignore the first (root) fs. Should already be
+			# mounted, but is still included in the 'zfs list'
+			#  above.
+			[ "${f}" = "${fs}" ] && continue
+
+			zfs_action "Mounting filesystem $f" mount_fs "${f}"
+		done
+	else
+		return 1
+	fi
+
+	return 0
+}
+
 load_module()
 {
 	# Load the zfs module stack
@@ -483,7 +501,7 @@ find_pools()
 	local CMD="$*"
 	local pools
 
-	pools=$($CMD 2> /dev/null | \
+	pools=$(${CMD} 2> /dev/null | \
 		grep -E "pool:|^[a-zA-Z0-9]" | \
 		sed 's@.*: @@' | \
 		sort | \
@@ -609,7 +627,9 @@ import_pool()
 		"Importing pool '${pool}' using defaults"
 
 	ZFS_CMD="${ZPOOL} import -N ${ZPOOL_FORCE} ${ZPOOL_IMPORT_OPTS}"
+	zfs_set_ifs "$OLD_IFS"
 	ZFS_STDERR="$($ZFS_CMD "$pool" 2>&1)"
+	zfs_set_ifs "$TMP_IFS"
 	ZFS_ERROR="$?"
 	if [ "${ZFS_ERROR}" != 0 ]
 	then
@@ -619,21 +639,28 @@ import_pool()
 			"Importing pool '${pool}' using cachefile."
 
 		ZFS_CMD="${ZPOOL} import -c ${ZPOOL_CACHE} -N ${ZPOOL_FORCE} ${ZPOOL_IMPORT_OPTS}"
+		zfs_set_ifs "$OLD_IFS"
 		ZFS_STDERR="$($ZFS_CMD "$pool" 2>&1)"
+		zfs_set_ifs "$TMP_IFS"
 		ZFS_ERROR="$?"
 		if [ "${ZFS_ERROR}" != 0 ]
 		then
 			[ "$quiet" != "y" ] && zfs_log_failure_msg "${ZFS_ERROR}"
 
 			disable_plymouth
-			echo ""
-			echo "Command: ${ZFS_CMD} '$pool'"
-			echo "Message: $ZFS_STDERR"
-			echo "Error: $ZFS_ERROR"
-			echo ""
-			echo "Failed to import pool '$pool'."
-			echo "Manually import the pool and exit."
-			/bin/sh
+			if [ "$?" != 999 ]; then
+				echo ""
+				echo "Command: ${ZFS_CMD} '$pool'"
+				echo "Message: $ZFS_STDERR"
+				echo "Error: $ZFS_ERROR"
+				echo ""
+				echo "Failed to import pool '$pool'."
+				echo "Manually import the pool and exit."
+				emergency_shell
+			else
+				[ -n "$ORIG_IFS" ] && IFS=$ORIG_IFS
+				return 1
+			fi
 		fi
 	fi
 
@@ -689,21 +716,27 @@ mount_fs()
 	[ -n "${ZFS_DEBUG}" ] && \
 	    zfs_log_begin_msg "CMD: '$ZFS_CMD ${fs} ${rootmnt}/${mountpoint}'"
 
+	zfs_set_ifs "$OLD_IFS"
 	ZFS_STDERR=$(${ZFS_CMD} "${fs}" "${rootmnt}/${mountpoint}" 2>&1)
+	zfs_set_ifs "$TMP_IFS"
 	ZFS_ERROR=$?
 	if [ "${ZFS_ERROR}" != 0 ]
 	then
 		[ "$quiet" != "y" ] && zfs_log_failure_msg "${ZFS_ERROR}"
 
 		disable_plymouth
-		echo ""
-		echo "Command: ${ZFS_CMD} ${fs} ${rootmnt}/${mountpoint}"
-		echo "Message: $ZFS_STDERR"
-		echo "Error: $ZFS_ERROR"
-		echo ""
-		echo "Failed to mount ${fs} on ${rootmnt}/${mountpoint}."
-		echo "Manually mount the filesystem and exit."
-		/bin/sh
+		if [ "$?" != 999 ]; then
+			echo ""
+			echo "Command: ${ZFS_CMD} ${fs} ${rootmnt}/${mountpoint}"
+			echo "Message: $ZFS_STDERR"
+			echo "Error: $ZFS_ERROR"
+			echo ""
+			echo "Failed to mount ${fs} on ${rootmnt}/${mountpoint}."
+			echo "Manually mount the filesystem and exit."
+			emergency_shell
+		else
+			return 1
+		fi
 	else
 		[ "$quiet" != "y" ] && zfs_log_end_msg
 	fi
@@ -741,24 +774,28 @@ decrypt_fs()
 			[ "$quiet" != "y" ] && zfs_log_failure_msg "${ZFS_ERROR}"
 
 			disable_plymouth
-			echo ""
-			echo "Command: $ZFS_CMD"
-			echo "Message: $ZFS_STDERR"
-			echo "Error: $ZFS_ERROR"
-			echo ""
-			echo "Failed to load $mod module."
-			echo "Please verify that it is availible on the initrd image"
-			echo "(without it it won't be possible to unlock the filesystem)"
-			echo "and rerun:  $ZFS_CMD"
-			/bin/sh
-		else
-			[ "$quiet" != "y" ] && zfs_log_end_msg
+			if [ "$?" != 999 ]; then
+				echo ""
+				echo "Command: $ZFS_CMD"
+				echo "Message: $ZFS_STDERR"
+				echo "Error: $ZFS_ERROR"
+				echo ""
+				echo "Failed to load $mod module."
+				echo "Please verify that it is availible on the initrd image"
+				echo "(without it it won't be possible to unlock the filesystem)"
+				echo "and rerun:  $ZFS_CMD"
+				emergency_shell
+			else
+				return 1
+			fi
 		fi
 	done
 
 	# If the key isn't availible, then this will fail!
 	ZFS_CMD="${ZFS} key -l -r $fs"
+	zfs_set_ifs "$OLD_IFS"
 	ZFS_STDERR="$(${ZFS_CMD} 2>&1)"
+	zfs_set_ifs "$TMP_IFS"
 	ZFS_ERROR="$?"
 
 	if [ "${ZFS_ERROR}" != 0 ]
@@ -766,15 +803,19 @@ decrypt_fs()
 		[ "$quiet" != "y" ] && zfs_log_failure_msg "${ZFS_ERROR}"
 
 		disable_plymouth
-		echo ""
-		echo "Command: $ZFS_CMD"
-		echo "Message: $ZFS_STDERR"
-		echo "Error: $ZFS_ERROR"
-		echo ""
-		echo "Failed to load zfs encryption wrapper key (s)."
-		echo "Please verify dataset property 'keysource' for datasets"
-		echo "and rerun:  $ZFS_CMD"
-		/bin/sh
+		if [ "$?" != 999 ]; then
+			echo ""
+			echo "Command: $ZFS_CMD"
+			echo "Message: $ZFS_STDERR"
+			echo "Error: $ZFS_ERROR"
+			echo ""
+			echo "Failed to load zfs encryption wrapper key (s)."
+			echo "Please verify dataset property 'keysource' for datasets"
+			echo "and rerun:  $ZFS_CMD"
+			emergency_shell
+		else
+			return 1
+		fi
 	else
 		[ "$quiet" != "y" ] && zfs_log_end_msg
 	fi
@@ -792,22 +833,28 @@ destroy_fs()
 	    zfs_log_begin_msg "Destroying '$fs'"
 
 	ZFS_CMD="${ZFS} destroy $fs"
+	zfs_set_ifs "$OLD_IFS"
 	ZFS_STDERR="$(${ZFS_CMD} 2>&1)"
+	zfs_set_ifs "$TMP_IFS"
 	ZFS_ERROR="$?"
 	if [ "${ZFS_ERROR}" != 0 ]
 	then
 		[ "$quiet" != "y" ] && zfs_log_failure_msg "${ZFS_ERROR}"
 
 		disable_plymouth
-		echo ""
-		echo "Command: $ZFS_CMD"
-		echo "Message: $ZFS_STDERR"
-		echo "Error: $ZFS_ERROR"
-		echo ""
-		echo "Failed to destroy '$fs'. Please make sure that '$fs' is not availible."
-		echo "Hint: Try:  zfs destroy -Rfn $fs"
-		echo "If this dryrun looks good, then remove the 'n' from '-Rfn' and try again."
-		/bin/sh
+		if [ "$?" != 999 ]; then
+			echo ""
+			echo "Command: $ZFS_CMD"
+			echo "Message: $ZFS_STDERR"
+			echo "Error: $ZFS_ERROR"
+			echo ""
+			echo "Failed to destroy '$fs'. Please make sure that '$fs' is not availible."
+			echo "Hint: Try:  zfs destroy -Rfn $fs"
+			echo "If this dryrun looks good, then remove the 'n' from '-Rfn' and try again."
+			emergency_shell
+		else
+			return 1
+		fi
 	else
 		[ "$quiet" != "y" ] && zfs_log_end_msg
 	fi
@@ -836,22 +883,28 @@ clone_snap()
 	ZFS_CMD="${ZFS} clone -o canmount=noauto -o mountpoint=none"
 	ZFS_CMD="${ZFS_CMD} -o org.zol:mountpoint=${mountpoint}"
 	ZFS_CMD="${ZFS_CMD} $snap $destfs"
+	zfs_set_ifs "$OLD_IFS"
 	ZFS_STDERR="$(${ZFS_CMD} 2>&1)"
+	zfs_set_ifs "$TMP_IFS"
 	ZFS_ERROR="$?"
 	if [ "${ZFS_ERROR}" != 0 ]
 	then
 		[ "$quiet" != "y" ] && zfs_log_failure_msg "${ZFS_ERROR}"
 
 		disable_plymouth
-		echo ""
-		echo "Command: $ZFS_CMD"
-		echo "Message: $ZFS_STDERR"
-		echo "Error: $ZFS_ERROR"
-		echo ""
-		echo "Failed to clone snapshot."
-		echo "Make sure that the any problems are corrected and then make sure"
-		echo "that the dataset '$destfs' exists and is bootable."
-		/bin/sh
+		if [ "$?" != 999 ]; then
+			echo ""
+			echo "Command: $ZFS_CMD"
+			echo "Message: $ZFS_STDERR"
+			echo "Error: $ZFS_ERROR"
+			echo ""
+			echo "Failed to clone snapshot."
+			echo "Make sure that the any problems are corrected and then make sure"
+			echo "that the dataset '$fs' exists and is bootable."
+			emergency_shell
+		else
+			return 1
+		fi
 	else
 		[ "$quiet" != "y" ] && zfs_log_end_msg
 	fi
@@ -868,20 +921,26 @@ rollback_snap()
 	[ "$quiet" != "y" ] && zfs_log_begin_msg "Rollback $snap"
 
 	ZFS_CMD="${ZFS} rollback -Rf $snap"
+	zfs_set_ifs "$OLD_IFS"
 	ZFS_STDERR="$(${ZFS_CMD} 2>&1)"
+	zfs_set_ifs "$TMP_IFS"
 	ZFS_ERROR="$?"
 	if [ "${ZFS_ERROR}" != 0 ]
 	then
 		[ "$quiet" != "y" ] && zfs_log_failure_msg "${ZFS_ERROR}"
 
 		disable_plymouth
-		echo ""
-		echo "Command: $ZFS_CMD"
-		echo "Message: $ZFS_STDERR"
-		echo "Error: $ZFS_ERROR"
-		echo ""
-		echo "Failed to rollback snapshot."
-		/bin/sh
+		if [ "$?" != 999 ]; then
+			echo ""
+			echo "Command: $ZFS_CMD"
+			echo "Message: $ZFS_STDERR"
+			echo "Error: $ZFS_ERROR"
+			echo ""
+			echo "Failed to rollback snapshot."
+			emergency_shell
+		else
+			return 1
+		fi
 	else
 		[ "$quiet" != "y" ] && zfs_log_end_msg
 	fi
@@ -1040,6 +1099,26 @@ disable_plymouth()
 	then
 		/bin/plymouth hide-splash >/dev/null 2>&1
 	else
+		# No plymouth. Return a high number that shouldn't
+		# mean anything to anyone but us.
 		return 999
 	fi
 }
+
+# This is defined in dracut, but nowhere
+# else. So create a wrapper.
+if ! type emergency_shell > /dev/null 2>&1 ; then
+	emergency_shell() { /bin/sh -i -l; }
+fi
+
+# For some reason, some functions in the library have a problem
+# with a changed IFS, so this function goes around that.
+zfs_set_ifs() {
+	local tIFS="$1"
+	if [ -n "$tIFS" ]
+	then
+		TMP_IFS="$IFS"
+		IFS="$tIFS"
+	fi
+}
+
diff --git a/contrib/shell-common/zfs.in b/contrib/shell-common/zfs.in
index 588bb3f90450..74a30d4d8850 100644
--- a/contrib/shell-common/zfs.in
+++ b/contrib/shell-common/zfs.in
@@ -31,6 +31,9 @@ DO_OVERLAY_MOUNTS='no'
 
 # Any additional option to the 'zfs import' commandline?
 # Include '-o' for each option wanted.
+# You don't need to put '-f' in here, unless you want it ALL the time.
+# Using the option 'zfsforce=1' on the grub/kernel command line will
+# do the same, but on a case-to-case basis.
 ZPOOL_IMPORT_OPTS=""
 
 # Any additional option to the 'zfs mount' command line?