Controlled EIO from the device is achieved using the dm device.
Helper functions are at common/dmerror.
Broadly steps will include calling _init_dm_error_dev() with a blk
device as an argument, typically this device can be a device pealed
from the SCRATCH_DEV_POOL, and init_dm_error_dev() will use
this blk device as backing store of dm linear device and assign
DM_ERROR_DEV to /dev/mapper/error-dev, which then can be assigned back
to the SCRATCH_DEV_POOL.
When test script is read to get EIO, the test cases can call
_load_dm_error_table() which then it will load the dm error.
so that reading DM_ERROR_DEV will cause EIO. After the test case is
complete, cleanup must be done by calling _cleanup_dm_error_dev().
Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
---
common/dmerror | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
common/rc | 18 ++++++++++++++++
2 files changed, 83 insertions(+)
create mode 100644 common/dmerror
diff --git a/common/dmerror b/common/dmerror
new file mode 100644
index 0000000..e1f92e6
--- /dev/null
+++ b/common/dmerror
@@ -0,0 +1,65 @@
+##/bin/bash
+#
+# Copyright (c) 2015 Oracle. 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 dmerror device
+
+_init_dm_error_dev()
+{
+ DM_ERROR_DEV=''
+ $DMSETUP_PROG remove error-dev > /dev/null 2>&1
+ DM_BLK_DEV=$1
+ [ -b $DM_BLK_DEV ] || _fatal "$DM_BLK_DEV is not a block device"
+
+ DM_DEV_SIZE=`blockdev --getsz $DM_BLK_DEV`
+ [ $? -ne 0 ] && _fatal "failed to failed to read block dev size"
+
+ LINEAR_TABLE="0 $DM_DEV_SIZE linear $DM_BLK_DEV 0"
+ $DMSETUP_PROG create error-dev --table "$LINEAR_TABLE" || \
+ _fatal "failed to create dm linear device"
+
+ DM_ERROR_DEV='/dev/mapper/error-dev'
+ blockdev --setra 0 $DM_ERROR_DEV
+ [ $? -ne 0 ] && _fatal "failed to failed to setra for $DM_ERROR_DEV"
+}
+
+_cleanup_dm_error_dev()
+{
+ DM_ERROR_DEV=''
+ $DMSETUP_PROG remove error-dev > /dev/null 2>&1
+}
+
+_load_dm_error_table()
+{
+ [ -z $DM_BLK_DEV ] && _fatal "DM_BLK_DEV is not set"
+ [ -z $DM_ERROR_DEV ] && _fatal "DM_ERROR_DEV is not set"
+ [ -z $DM_DEV_SIZE ] && _fatal "DM_DEV_SIZE is not set call init_error_dev first"
+
+ echo 3 > /proc/sys/vm/drop_caches
+ $DMSETUP_PROG suspend error-dev
+ [ $? -ne 0 ] && _fatal "failed to suspend error-dev"
+
+ ERROR_TABLE="0 $DM_DEV_SIZE error $DM_BLK_DEV 0"
+ $DMSETUP_PROG load error-dev --table "$ERROR_TABLE"
+ [ $? -ne 0 ] && _fatal "failed to load table into error-dev"
+
+ $DMSETUP_PROG resume error-dev
+ [ $? -ne 0 ] && _fatal "failed to resume error-dev"
+
+ dd if=$DM_ERROR_DEV of=/dev/null count=1 > /dev/null 2>&1
+ [ $? -ne 0 ] || _fatal "failed to fail IO to $DM_ERROR_DEV"
+}
diff --git a/common/rc b/common/rc
index c5db0dd..2a50491 100644
--- a/common/rc
+++ b/common/rc
@@ -1305,6 +1305,24 @@ _require_block_device()
fi
}
+# this test requires the device mapper error target
+#
+_require_dm_error()
+{
+ DM_BACKSTORE_DEV=$1
+ # require SCRATCH_DEV to be a valid block device
+ _require_block_device $DM_BACKSTORE_DEV
+ _require_command "$DMSETUP_PROG" dmsetup
+
+ $DMSETUP_PROG targets | grep error >/dev/null 2>&1
+ if [ $? -eq 0 ]
+ then
+ :
+ else
+ _notrun "This test requires dm error support"
+ fi
+}
+
# this test requires the device mapper flakey target
#
_require_dm_flakey()
--
2.0.0.153.g79dcccc
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