On Mon, Sep 11, 2017 at 08:06:04AM -0400, John Ferlan wrote: > > > On 09/11/2017 07:26 AM, Peter Krempa wrote: > > On Wed, Sep 06, 2017 at 12:05:32 -0400, John Ferlan wrote: > >> https://bugzilla.redhat.com/show_bug.cgi?id=1477880 > >> > >> If the "/#" is missing from the provided iSCSI path, then we need > >> to provide the default LUN of /0; otherwise, QEMU will fail to parse > >> the URL causing a failure to either create the guest or hotplug > >> attach the storage. > >> > >> Alter the command lines generated appropriately. This change does not > >> effect the XML input files. > >> > >> One 'side effect' of this for the argv2xml is that if a "/0" is found > >> on the command line, then the generated XML would need to add the "/0" > >> to the output XML since it wouldn't be known whether it existed or not > >> at qemu process creation time. > >> > >> Signed-off-by: John Ferlan <jferlan@xxxxxxxxxx> > >> --- > >> NB: Investigated the history quite a bit between QEMU and libiscsi and > >> it seems as though this probably never worked and of course never "tested" > >> in a real environment. Ironically, in qapi/block-core.json, it is claimed > >> that the LUN would default to 0, but the block/iscsi.c code that calls > >> iscsi_parse_full_url would never (AFAICT) have supported not supplying > >> some LUN on the command line. > >> > >> src/qemu/qemu_command.c | 20 ++++++++++++++++---- > >> .../qemuargv2xml-disk-drive-network-iscsi.args | 2 +- > >> .../qemuargv2xml-disk-drive-network-iscsi.xml | 2 +- > >> .../qemuxml2argv-disk-drive-network-iscsi-lun.args | 2 +- > >> .../qemuxml2argv-disk-drive-network-iscsi.args | 2 +- > >> .../qemuxml2argv-hostdev-scsi-lsi-iscsi.args | 2 +- > >> .../qemuxml2argv-hostdev-scsi-virtio-iscsi.args | 2 +- > >> 7 files changed, 22 insertions(+), 10 deletions(-) > >> > >> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c > >> index ed8cb6e..cff84de 100644 > >> --- a/src/qemu/qemu_command.c > >> +++ b/src/qemu/qemu_command.c > >> @@ -830,10 +830,22 @@ qemuBuildNetworkDriveURI(virStorageSourcePtr src, > >> src->volume, src->path) < 0) > >> goto cleanup; > >> } else { > >> - if (virAsprintf(&uri->path, "%s%s", > >> - src->path[0] == '/' ? "" : "/", > >> - src->path) < 0) > >> - goto cleanup; > >> + if (src->protocol == VIR_STORAGE_NET_PROTOCOL_ISCSI && > >> + !strchr(src->path, '/')) { > >> + > >> + /* The details of iqn is defined by RFC 3720 and 3721, but > >> + * we just need to make sure there's a lun provided. If not > >> + * provided, then default to zero. If ISCSI LUN is provided > >> + * by /dev/disk/by-path/... , then that path will have the > >> + * specific lun requested. */ > >> + if (virAsprintf(&uri->path, "/%s/0", src->path) < 0) > >> + goto cleanup; > >> + } else { > >> + if (virAsprintf(&uri->path, "%s%s", > >> + src->path[0] == '/' ? "" : "/", > >> + src->path) < 0) > >> + goto cleanup; > >> + } > >> } > >> } > > > > The command line generator is not really the correct place to add > > defaults. We have the post parse callbacks for this, and the LUN clearly > > should be marked in the XML > > > > Sure, but doing so would then change the provided XML, right? Is that > the desired outcome - to change and save the provided XML? IDC, it just > that this point doesn't alter that XML - rather just the command line > which seemed a bit safer to me. Everything that we pass to QEMU command line should be also in XML, the main reason is migration. If some default value is not in the XML and we change the default value in our code migration to a libvirt where the default value is different may fail or may change ABI. Pavel
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