[PATCH 1/2] dm-thinp helpers in common/dmthin

Eric Sandeen
2015-10-21T20:53:24Z

Basic dm-thinp helpers to set up, tear down, grow, check,
and set no-space behavior for a single thin dm volume built
on $SCRATCH_DEV.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

diff --git a/common/dmthin b/common/dmthin
new file mode 100644
index 0000000..0c0d20d
--- /dev/null
+++ b/common/dmthin
@@ -0,0 +1,238 @@
+#!/bin/bash
+#
+# Copyright (c) 2015 Red Hat, Inc. All Rights Reserved.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it would be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write the Free Software Foundation,
+# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+#
+#
+# common functions for setting up and tearing down a dmthin device
+
+# SOOO many devices!
+# Create the 2 pool devices on lvs so we can build the whole thing
+# from a single scratch device
+
+# Backing data dev
+DMTHIN_DATA_NAME="thin-data"
+DMTHIN_DATA_DEV="/dev/mapper/$DMTHIN_DATA_NAME"
+# Backing metadata dev
+DMTHIN_META_NAME="thin-meta"
+DMTHIN_META_DEV="/dev/mapper/$DMTHIN_META_NAME"
+# Backing pool dev (combination of above)
+DMTHIN_POOL_NAME="thin-pool"
+DMTHIN_POOL_DEV="/dev/mapper/$DMTHIN_POOL_NAME"
+# Thin volume
+DMTHIN_VOL_NAME="thin-vol"
+DMTHIN_VOL_DEV="/dev/mapper/$DMTHIN_VOL_NAME"
+
+_dmthin_cleanup()
+{
+ $UMOUNT_PROG $SCRATCH_MNT > /dev/null 2>&1
+ $DMSETUP_PROG remove $DMTHIN_VOL_NAME> /dev/null 2>&1
+ $DMSETUP_PROG remove $DMTHIN_POOL_NAME> /dev/null 2>&1
+ $DMSETUP_PROG remove $DMTHIN_META_NAME> /dev/null 2>&1
+ $DMSETUP_PROG remove $DMTHIN_DATA_NAME> /dev/null 2>&1
+}
+
+_dmthin_check_fs()
+{
+ _check_scratch_fs $DMTHIN_VOL_DEV
+}
+
+# Set up a dm-thin device on $SCRATCH_DEV
+#
+# All arguments are optional, and in this order; defaults follows:
+# data_dev_size: half of $SCRATCH_DEV
+# virtual_size: 10x $data_dev_size
+# cluster_size: 512k
+# low_water: 100M
+#
+# You may specify 0 to 4 of these arguments, but they
+# must be in the above order.
+_dmthin_init()
+{
+ local data_dev_size=$1 # Backing pool data size in sectors
+ local virtual_size=$2 # Virtual size in sectors
+ local cluster_size=$3 # cluster/alloc size, sectors
+ local low_water=$4 # low water mark, sectors
+
+ local dm_backing_dev=$SCRATCH_DEV
+ local blk_dev_size=`blockdev --getsz $dm_backing_dev`
+
+ local pool_id=$RANDOM
+
+ # Default to something small-ish
+ if [ -z "$data_dev_size" ]; then
+ data_dev_size=$(($blk_dev_size / 2))
+ fi
+
+ # Default to something big-is; 10x backing
+ if [ -z "$virtual_size" ]; then
+ virtual_size=$(($data_dev_size * 10))
+ fi
+
+ # Default to 512k
+ if [ -z "$cluster_size" ]; then
+ cluster_size=1024 # 512k in sectors
+ fi
+
+ # Default to 100M
+ if [ -z "$low_water" ]; then
+ low_water=204800 # 100M, in sectors
+ fi
+
+ # Need to make linear metadata and data devs. From kernel docs:
+ # As a guide, we suggest you calculate the number of bytes to use in the
+ # metadata device as 48 * $data_dev_size / $data_block_size but round it up
+ # to 2MB (4096 sectors) if the answer is smaller.
+ # So do that:
+
+ local meta_dev_size=$((48 * $data_dev_size / $cluster_size))
+ if [ "$meta_dev_size" -lt "4096" ]; then
+ meta_dev_size=4096 # 2MB
+ fi
+
+ # scratch dev gets a metadata vol & data vol, start at this offset
+ local meta_dev_offset=10240
+
+ local total_data_dev_size=$(($meta_dev_offset + $meta_dev_size + $data_dev_size))
+ if [ "$total_data_dev_size" -gt "$blk_dev_size" ]; then
+ _notrun "$SCRATCH_DEV too small"
+ fi
+
+ # Unmount & tear down old stuff
+ _dmthin_cleanup
+
+ # Metadata device
+ DMTHIN_META_TABLE="0 $meta_dev_size linear $dm_backing_dev $meta_dev_offset"
+ $DMSETUP_PROG create $DMTHIN_META_NAME --table "$DMTHIN_META_TABLE" || \
+ _fatal "failed to create dm thin meta device"
+
+ # Data device
+ local data_dev_offset=$((meta_dev_offset + $meta_dev_size))
+ DMTHIN_DATA_TABLE="0 $data_dev_size linear $dm_backing_dev $data_dev_offset"
+ $DMSETUP_PROG create $DMTHIN_DATA_NAME --table "$DMTHIN_DATA_TABLE" || \
+ _fatal "failed to create dm thin data device"
+
+ # Zap the pool metadata dev
+ dd if=/dev/zero of=$DMTHIN_META_DEV bs=4096 count=1 &>/dev/null
+
+ # Thin pool
+ # "start length thin-pool metadata_dev data_dev data_block_size low_water_mark"
+ DMTHIN_POOL_TABLE="0 $data_dev_size thin-pool $DMTHIN_META_DEV $DMTHIN_DATA_DEV $cluster_size $low_water"
+ $DMSETUP_PROG create $DMTHIN_POOL_NAME --table "$DMTHIN_POOL_TABLE" || \
+ _fatal "failed to create dm thin pool device"
+
+ # Thin volume
+ $DMSETUP_PROG message $DMTHIN_POOL_DEV 0 "create_thin $pool_id" || \
+ _fatal "failed to message pool device"
+
+ # start length thin pool_dev dev_id [external_origin_dev]
+ DMTHIN_VOL_TABLE="0 $virtual_size thin $DMTHIN_POOL_DEV $pool_id"
+ $DMSETUP_PROG create $DMTHIN_VOL_NAME --table "$DMTHIN_VOL_TABLE" || \
+ _fatal "failed to create dm thin volume device"
+
+}
+
+# for internal use
+_dmthin_reload_table()
+{
+ local dev_name=$1
+ local table="$2"
+
+ $DMSETUP_PROG suspend $dev_name || \
+ _fail "dmsetup suspend of $dev_name failed"
+
+ $DMSETUP_PROG load $dev_name --table "$table" || \
+ _fail "dmsetup failed to reload $dev_name table"
+
+ $DMSETUP_PROG resume $dev_name || \
+ _fail "dmsetup resume of $dev_name failed"
+
+}
+
+# Grow the dm-thin device by the given amount
+# Argument is number of sectors to add, if not specified
+# defaults to 1/4 of the $SCRATCH_DEV size
+_dmthin_grow()
+{
+ local add_sectors=$1 # Number of sectors to add
+
+ local dm_backing_dev=$SCRATCH_DEV
+ local blk_dev_size=`blockdev --getsz $dm_backing_dev`
+
+ # Get current sizes & values
+ local meta_dev_size=`$DMSETUP_PROG table | grep $DMTHIN_META_NAME | awk '{print $3}'`
+ local meta_dev_offset=`$DMSETUP_PROG table | grep $DMTHIN_META_NAME | awk '{print $6}'`
+ local data_dev_size=`$DMSETUP_PROG table | grep $DMTHIN_DATA_NAME | awk '{print $3}'`
+ local pool_dev_size=`$DMSETUP_PROG table | grep $DMTHIN_POOL_NAME | awk '{print $3}'`
+ local cluster_size=`$DMSETUP_PROG table | grep $DMTHIN_POOL_NAME | awk '{print $7}'`
+ local low_water=`$DMSETUP_PROG table | grep $DMTHIN_POOL_NAME | awk '{print $8}'`
+
+ # default to 25% growth
+ if [ -z "$add_sectors" ]; then
+ add_sectors=$(($data_dev_size / 4))
+ fi
+
+ local data_dev_offset=$(($meta_dev_offset + $meta_dev_size))
+
+ # Figure new sizes
+ data_dev_size=$(($data_dev_size + $add_sectors))
+ pool_dev_size=$(($pool_dev_size + $add_sectors))
+
+ # Can we do this?
+ local total_data_dev_size=$(($meta_dev_offset + $meta_dev_size + $data_dev_size))
+ if [ "$total_data_dev_size" -gt "$blk_dev_size" ]; then
+ _fail "$SCRATCH_DEV too small"
+ fi
+
+ # Grow the data device
+ DMTHIN_DATA_TABLE="0 $data_dev_size linear $dm_backing_dev $data_dev_offset"
+ _dmthin_reload_table $DMTHIN_DATA_NAME "$DMTHIN_DATA_TABLE"
+
+ # Grow the pool
+ DMTHIN_POOL_TABLE="0 $data_dev_size thin-pool $DMTHIN_META_DEV $DMTHIN_DATA_DEV $cluster_size $low_water"
+ _dmthin_reload_table $DMTHIN_POOL_NAME "$DMTHIN_POOL_TABLE"
+}
+
+# Queue IOs when full
+_dmthin_set_queue()
+{
+ local data_dev_size=`$DMSETUP_PROG table | grep $DMTHIN_DATA_NAME | awk '{print $3}'`
+ local cluster_size=`$DMSETUP_PROG table | grep $DMTHIN_POOL_NAME | awk '{print $7}'`
+ local low_water=`$DMSETUP_PROG table | grep $DMTHIN_POOL_NAME | awk '{print $8}'`
+
+ DMTHIN_POOL_TABLE="0 $data_dev_size thin-pool $DMTHIN_META_DEV $DMTHIN_DATA_DEV $cluster_size $low_water"
+ _dmthin_reload_table $DMTHIN_POOL_NAME "$DMTHIN_POOL_TABLE"
+}
+
+# Fail IOs when full
+_dmthin_set_fail()
+{
+ local data_dev_size=`$DMSETUP_PROG table | grep $DMTHIN_DATA_NAME | awk '{print $3}'`
+ local cluster_size=`$DMSETUP_PROG table | grep $DMTHIN_POOL_NAME | awk '{print $7}'`
+ local low_water=`$DMSETUP_PROG table | grep $DMTHIN_POOL_NAME | awk '{print $8}'`
+
+ DMTHIN_POOL_TABLE="0 $data_dev_size thin-pool $DMTHIN_META_DEV $DMTHIN_DATA_DEV $cluster_size $low_water 1 error_if_no_space"
+ _dmthin_reload_table $DMTHIN_POOL_NAME "$DMTHIN_POOL_TABLE"
+}
+
+_dmthin_mount_options()
+{
+ echo `_common_dev_mount_options $*` $DMTHIN_VOL_DEV $SCRATCH_MNT
+}
+
+_dmthin_mount()
+{
+ _mount -t $FSTYP `_dmthin_mount_options $*`
+}