Re: dracut does not mount iscsi targets specified using --mount option

[Vivek Goyal <vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On Wed, Apr 25, 2012 at 04:22:25PM +0200, Harald Hoyer wrote:
> Am 25.04.2012 16:14, schrieb Vivek Goyal:
> > On Wed, Apr 25, 2012 at 03:57:34PM +0200, Harald Hoyer wrote:
> >> Am 25.04.2012 15:46, schrieb Vivek Goyal:
> >>> On Wed, Apr 25, 2012 at 11:26:15AM +0200, Harald Hoyer wrote:
> >>>
> >>> Hi Harald,
> >>>
> >>> [..]
> >>>>      is_mpath() {
> >>>> -        [ -e /sys/dev/block/$1/dm/uuid ] || return 1
> >>>> -        [[ $(cat /sys/dev/block/$1/dm/uuid) =~ ^mpath- ]] && return 0
> >>>> +        local _dev
> >>>> +        _dev=${1##/dev/}
> >>>> +        [ -e /sys/dev/block/$_dev/dm/uuid ] || return 1
> >>>> +        [[ $(cat /sys/dev/block/$_dev/dm/uuid) =~ ^mpath- ]] && return 0
> >>>
> >>> Will this work? _dev is device name (sda) and /sys/dev/block/ has links
> >>> based on device "maj:min". I applied this patch and ran dracut and I 
> >>> see that multipath module did not get included.
> >>>
> >>> Thanks
> >>> Vivek
> >>
> >> oh.. you are right:
> >>
> >> diff --git a/modules.d/90multipath/module-setup.sh
> >> b/modules.d/90multipath/module-setup.sh
> >> index ae9ec59..2af112a 100755
> >> --- a/modules.d/90multipath/module-setup.sh
> >> +++ b/modules.d/90multipath/module-setup.sh
> >> @@ -12,7 +12,7 @@ check() {
> >>
> >>      is_mpath() {
> >>          local _dev
> >> -        _dev=${1##/dev/}
> >> +        _dev=$(get_maj_min $1)
> >>          [ -e /sys/dev/block/$_dev/dm/uuid ] || return 1
> >>          [[ $(cat /sys/dev/block/$_dev/dm/uuid) =~ ^mpath- ]] && return 0
> >>          return 1
> >> diff --git a/modules.d/95iscsi/module-setup.sh b/modules.d/95iscsi/module-setup.sh
> >> index 34e101c..bfd9d73 100755
> >> --- a/modules.d/95iscsi/module-setup.sh
> >> +++ b/modules.d/95iscsi/module-setup.sh
> >> @@ -16,7 +16,7 @@ check() {
> >>
> >>      is_iscsi() (
> >>          local _dev
> >> -        _dev=${1##/dev/}
> >> +        _dev=$(get_maj_min $1)
> >>
> >>          [[ -L /sys/dev/block/$_dev ]] || return
> >>          cd "$(readlink -f /sys/dev/block/$_dev)"
> > 
> > Thanks Harald.
> > 
> > This fixes the issue for multipath.
> > 
> > For iscsi, I see that after this change iscsi module is included but iscsi
> > target bring up still does not happen so iscsi luns don't show up in second
> > kernel.
> > 
> > I think iscsi code might be assuing that we will pass some iscsi
> > parameters on command line but we don't have any information and we
> > don't pass anything. So iscsi module need save some files/state in
> > initramfs during build and bring up iscsi targets accordingly.
> > 
> > In RHEL6, during the block device stack traversal, I had saved the
> > target information in a file and packed that file in initramfs. And
> > then invoked code in initramfs to specifically bring up those luns.
> > 
> > I need to read up some code and also see if network modules are being
> > included or not and if networking is coming up or not before iscsi
> > can come up.
> > 
> > Thanks
> > Vivek
> 
> Just drop a iscsi.conf file in the initramfs /etc/cmdline.d either via your
> module-setup.sh or:
> 
> echo
> 'netroot=iscsi:[<username>:<password>[:<reverse>:<password>]@][<servername>]:[<protocol>]:[<port>][:[<iscsi_iface_name>]:[<netdev_name>]]:[<LUN>]:<targetname>'
> > iscsi.conf
> 
> dracut -i iscsi.conf /etc/cmdline.d/iscsi.conf ....

Problem is that I don't know all the details in kdump. Only thing user
has told kdump is top level mount point. We don't even know that this 
mount point is on top of multipath + iscsi + underlying network.

I was hoping that iscsi dracut module will store all the relevant 
information when it finds a device is iscsi device and bring that
device up in second kernel. That includes storing information about
network card and bringing it up.

We have device traversal code in rhel6 mkdumprd but I end up duplicating
all the code in rhel7 kdump, then it just increases the complexity
in kdump module.

I was hoping that generic iscsi dracut-module will take care of storing
all the info itself once it knows it has said "yes" to an iscsi device
in check() function.

Thanks
Vivek