[Cluster-devel] [GFS2 PATCH v2] gfs2-utils: Fix hang on withdraw

[Andrew Price <anprice@redhat.com>]

Hi Abhi,

Thanks for adding the docs, this looks good to me.

Cheers,
Andy

On 04/08/15 17:05, Abhijith Das wrote:
> Issuing a withdraw on a gfs2 filesystem causes a hang. When
> gfs_controld was removed, the userspace functionality that
> completes a withdraw operation went away. This causes gfs2
> kernel to hang waiting for a withdraw completion ack from
> userspace.
>
> This patchset introduces a uevent-based shell script to do
> the job that gfs_controld used to do on withdraw. An 'offline'
> uevent triggers the execution of this script. This script
> suspends the device associated with the filesystem and signals
> a completed withdraw to the kernel.
>
> Resolves: rhbz#1225634
> Signed-off-by: Abhi Das <adas@redhat.com>
> ---
>   README.build                        |  9 +++++++++
>   gfs2/scripts/82-gfs2-withdraw.rules |  2 ++
>   gfs2/scripts/Makefile.am            |  5 +++++
>   gfs2/scripts/gfs2_wd_udev.sh        | 30 ++++++++++++++++++++++++++++++
>   4 files changed, 46 insertions(+)
>   create mode 100644 gfs2/scripts/82-gfs2-withdraw.rules
>   create mode 100755 gfs2/scripts/gfs2_wd_udev.sh
>
> diff --git a/README.build b/README.build
> index f4ebe53..6487bae 100644
> --- a/README.build
> +++ b/README.build
> @@ -29,5 +29,14 @@ To install gfs2-utils, run:
>
>       make install
>
> +The following scripts (located in gfs2/scripts) are used to complete
> +the userland portion of the gfs2 withdraw feature using uevents. They
> +are not installed by 'make install' and need to be installed manually
> +or during rpm installation to the corresponding locations.
> +
> +	82-gfs2-withdraw.rules in /etc/udev/rules.d/
> +	gfs2_wd_udev.sh        in /usr/sbin/
> +
>   See also doc/README.contributing for details on submitting patches and
>   doc/README.tests for more details regarding the test suite.
> +
> diff --git a/gfs2/scripts/82-gfs2-withdraw.rules b/gfs2/scripts/82-gfs2-withdraw.rules
> new file mode 100644
> index 0000000..2228615
> --- /dev/null
> +++ b/gfs2/scripts/82-gfs2-withdraw.rules
> @@ -0,0 +1,2 @@
> +SUBSYSTEM=="gfs2", ACTION=="offline", RUN+="/bin/sh /usr/sbin/gfs2_wd_udev.sh"
> +
> diff --git a/gfs2/scripts/Makefile.am b/gfs2/scripts/Makefile.am
> index 62fb2fe..dde906f 100644
> --- a/gfs2/scripts/Makefile.am
> +++ b/gfs2/scripts/Makefile.am
> @@ -3,3 +3,8 @@ MAINTAINERCLEANFILES = Makefile.in
>   dist_sbin_SCRIPTS = \
>   	gfs2_lockcapture \
>   	gfs2_trace
> +
> +noinst_SCRIPTS = \
> +	82-gfs2-withdraw.rules \
> +	gfs2_wd_udev.sh
> +
> diff --git a/gfs2/scripts/gfs2_wd_udev.sh b/gfs2/scripts/gfs2_wd_udev.sh
> new file mode 100755
> index 0000000..ac3ce35
> --- /dev/null
> +++ b/gfs2/scripts/gfs2_wd_udev.sh
> @@ -0,0 +1,30 @@
> +#!/bin/sh
> +#
> +# Do not run this script manually. This script is called by udev on a gfs2
> +# withdraw uevent and is used to complete the withdraw action and notify the
> +# kernel.
> +#
> +
> +# Sanity checks
> +if [ "$SUBSYSTEM" != "gfs2" ] || [ "$LOCKPROTO" != "lock_dlm" ] ||
> +       [ -z "$DEVPATH" ] || [ "$ACTION" != "offline" ]
> +then
> +    exit 1 # Nothing to do here
> +fi
> +
> +# Try and suspend the device
> +SYSFS_TOPDIR="/sys"$DEVPATH
> +DM_NAME=$(cat "$SYSFS_TOPDIR/device/dm/name")
> +DM_DEV="/dev/mapper/"$DM_NAME
> +
> +if [ -z "$DM_DEV" ]
> +then
> +    /usr/bin/dmsetup suspend $DM_DEV
> +fi
> +
> +# Signal completion of withdraw
> +WD_ACK="$SYSFS_TOPDIR/lock_module/withdraw"
> +if [ -f "$WD_ACK" ]
> +then
> +    echo "1" > $WD_ACK
> +fi
>