[libvirt] [PATCH 1/2] util: Introduce virISCSINodeNew

[Ján Tomko]

On Mon, Jul 18, 2016 at 07:37:20AM -0400, John Ferlan wrote:
>https://bugzilla.redhat.com/show_bug.cgi?id=1356436
>
>According to RFC 3721 (https://www.ietf.org/rfc/rfc3721.txt), there are
>two ways to "discover" targets in/for the iSCSI environment. Discovery
>is the process which allows the initiator to find the targets to which
>it has access and at least one address at which each target may be
>accessed.
>
>The method currently implemented in libvirt using the virISCSIScanTargets
>API is known as "SendTargets" discovery. This method is more useful when
>the target IP Address and TCP port information are available, e.g. in
>libvirt terms the "portal". It returns a list of targets for the portal.
>>From that list, the target can be found. This operation can also fill an
>iSCSI node table into which iSCSI logins may occur. Commit id '56057900'
>altered that filling by adding the "--op nonpersistent" since it was
>not necessarily desired to perform that for non libvirt related targets.
>
>The second method is "Static Configuration". This method not only needs
>the IP Address and TCP port (e.g. portal), but also the iSCSI target name.
>In libvirt terms this would be the device path field from the iSCSI pool
><source> XML. This patch implements the second methodology using that
>required device path as the targetname.
>
>Signed-off-by: John Ferlan <jferlan at redhat.com>
>---
> src/libvirt_private.syms |  1 +
> src/util/viriscsi.c      | 45 +++++++++++++++++++++++++++++++++++++++++++++
> src/util/viriscsi.h      |  6 ++++++
> 3 files changed, 52 insertions(+)
>
>diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
>index 3580a72..edef70b 100644
>--- a/src/libvirt_private.syms
>+++ b/src/libvirt_private.syms
>@@ -1714,6 +1714,7 @@ iptablesRemoveUdpOutput;
> virISCSIConnectionLogin;
> virISCSIConnectionLogout;
> virISCSIGetSession;
>+virISCSINodeNew;
> virISCSINodeUpdate;
> virISCSIRescanLUNs;
> virISCSIScanTargets;
>diff --git a/src/util/viriscsi.c b/src/util/viriscsi.c
>index e705517..8115d09 100644
>--- a/src/util/viriscsi.c
>+++ b/src/util/viriscsi.c
>@@ -444,6 +444,51 @@ virISCSIScanTargets(const char *portal,
>     return ret;
> }
>
>+/*
>+ * virISCSINodeNew:
>+ * @portal: address for iSCSI target
>+ * @target: IQN and specific LUN target
>+ *
>+ * Usage of nonpersistent discovery in virISCSIScanTargets is useful primarily
>+ * only when the target IQN is not known; however, since we have the target IQN
>+ * usage of the "--op new" can be done. This avoids problems if "--op delete"
>+ * had been used wiping out the static nodes determined by the scanning of
>+ * all targets.
>+ *
>+ * NB: If already created, subsequent "--op new" commands do not return
>+ * an error.

If it does not return an error, do we need to ignore non-zero status?

AFAIK the rest of the code ignoring exit codes was written before iscsiadm
returned them properly:
https://github.com/open-iscsi/open-iscsi/commit/2c839a2

Even this libvirt commit from Jan 2010 speaks of 'older versions of
iscsiadm':
http://libvirt.org/git/?p=libvirt.git;a=commitdiff;h=6aabcb5b

Jan