From: "Roger Pau Monné" <roger.pau@citrix.com> To: George Dunlap <george.dunlap@citrix.com> Cc: "Ian Jackson" <ian.jackson@citrix.com>, xen-devel@lists.xen.org, "Wei Liu" <wei.liu2@citrix.com>, "Roger Pau Monné" <roger.pau@citrix.com> Subject: Re: [PATCH v2 8/9] docs: Document block-script protocol Date: Wed, 23 Mar 2016 13:14:24 +0100 [thread overview] Message-ID: <alpine.OSX.2.20.1603231304040.753@mac> (raw) In-Reply-To: <56F27BBF.3060702@citrix.com> [-- Attachment #1: Type: text/plain, Size: 3291 bytes --] On Wed, 23 Mar 2016, George Dunlap wrote: > On 22/03/16 12:52, Roger Pau Monné wrote: > > On Mon, 21 Mar 2016, George Dunlap wrote: > >> Signed-off-by: George Dunlap <george.dunlap@citrix.com> > >> --- > >> Changes since v1: > >> - Attempt to make a clear distinction between custom hotplug scripts > >> and the script called for raw physical devices and files > >> > >> CC: Ian Jackson <ian.jackson@citrix.com> > >> CC: Wei Liu <wei.liu2@citrix.com> > >> CC: Roger Pau Monne <roger.pau@citrix.com> > >> --- > >> docs/misc/block-scripts.txt | 101 ++++++++++++++++++++++++++++++++++++++++++++ > >> 1 file changed, 101 insertions(+) > >> > >> diff --git a/docs/misc/block-scripts.txt b/docs/misc/block-scripts.txt > >> new file mode 100644 > >> index 0000000..6dd5d48 > >> --- /dev/null > >> +++ b/docs/misc/block-scripts.txt > >> @@ -0,0 +1,101 @@ > > [...] > >> +Inputs > >> +------ > >> + > >> +In all cases, the scripts are called with either "add" or "remove" as > >> +the command. For custom scripts, the command will be the first > >> +argument of the script (i.e. $1). > >> + > >> +The environment variable XENBUS_PATH will be set to the > >> +path for the block device to be created. > > > > This is true for Linux, but not for NetBSD. On NetBSD no env variables are > > needed, and everything is passed as arguments using the following format: > > > > ./<script> <backend_path> <xenbus state> > > > > Where xenbus state is either 2 or 6. > > > > On FreeBSD I'm aiming of using the same input interface for both block and > > network scripts, and it is the following: > > > > ./<script> {add/remove} <backend path> > > > > With no env variables provided at all. So either this section is expanded, > > or it is labelled as "Linux Inputs". > > Nothing like consistency across implementations. :-) > > So in the case of NetBSD, "2" means 'add' and "6" means 'remove'? Or > how does that work? Yes, 2 means add and 6 remove. > Presumably there's not much we can do about NetBSD at this point, if > there are (or may be) out-of-tree scripts that expect the new format. > But unless there's a good reason, it seems like we should try to > converge the hotplug script protocol. > > Was there a particular reason you wanted to use an argument instead of > an environment variable? If not, it's probably better to just follow > suit with the Linux protocol. Don't get me wrong, but the Linux protocol is all but consistent :). I'm not sure if those other env variables are used by the block hotplug scripts, but we also set: script=<script_name> XENBUS_TYPE=<vbd/vif> XENBUS_PATH=<be_path> XENBUS_BASE_PATH="backend" And it's even worse for vifs, where the action parameter that we pass to the hotplug script is different depending on whether we are dealing with a PV or an emulated interface (PV uses "online/offline", while emulated use "add/remove"). I would like to share the same interface, but I think the Linux one is simply too broken, and I don't want to put this anywhere close to FreeBSD. There at least I have a chance of having something that's simple and rational. > If there is a good reason, we could consider changing the Linux protocol > as well (leaving the environment variable in for backwards-compatibility > purposes). > > -George > [-- Attachment #2: Type: text/plain, Size: 126 bytes --] _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
next prev parent reply other threads:[~2016-03-23 12:14 UTC|newest] Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-03-21 18:16 [PATCH v2 0/9] tools: Allow HVM domains emulated access to disks provided by hotplug scripts George Dunlap 2016-03-21 18:16 ` [PATCH v2 1/9] tools/hotplug: Add a "dummy" hotplug script for testing George Dunlap 2016-03-21 18:16 ` [PATCH v2 2/9] libxl: Remove redundant setting of phyical-device George Dunlap 2016-03-21 18:16 ` [PATCH v2 3/9] tools/hotplug: Write physical-device-path in addition to physical-device George Dunlap 2016-03-21 18:16 ` [PATCH v2 4/9] libxl: Move check for local access to a funciton George Dunlap 2016-03-21 18:16 ` [PATCH v2 5/9] libxl: Rearrange qemu upstream disk argument code George Dunlap 2016-03-21 18:16 ` [PATCH v2 6/9] libxl: Share logic for finding path between qemuu and pygrub George Dunlap 2016-03-22 10:38 ` George Dunlap 2016-03-21 18:16 ` [PATCH v2 7/9] libxl: Allow local access for block devices with hotplug scripts George Dunlap 2016-03-21 18:17 ` [PATCH v2 8/9] docs: Document block-script protocol George Dunlap 2016-03-22 12:52 ` Roger Pau Monné 2016-03-23 11:19 ` George Dunlap 2016-03-23 12:14 ` Roger Pau Monné [this message] 2016-03-24 16:29 ` George Dunlap 2016-03-24 16:51 ` Roger Pau Monné 2016-03-21 18:17 ` [PATCH v2 9/9] DO NOT APPLY libxl: Change hotplug script interface to use physical-device-path George Dunlap 2016-03-23 10:10 ` [PATCH v2 0/9] tools: Allow HVM domains emulated access to disks provided by hotplug scripts Roger Pau Monné 2016-03-23 10:36 ` George Dunlap
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