From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Benjamin Marzinski" Subject: Re: [PATCH v4 19/20] libmultipath: enable find_multipaths "smart" Date: Thu, 12 Apr 2018 13:47:09 -0500 Message-ID: <20180412184709.GU3103@octiron.msp.redhat.com> References: <20180404161627.6244-1-mwilck@suse.com> <20180404161627.6244-20-mwilck@suse.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20180404161627.6244-20-mwilck@suse.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Martin Wilck Cc: dm-devel@redhat.com, Julian Andres Klode List-Id: dm-devel.ids On Wed, Apr 04, 2018 at 06:16:26PM +0200, Martin Wilck wrote: > This activates "smart" path detection. This is similar to > "find_multipaths yes", but doesn't generally ignore single paths > that are not listed in the WWIDs file. Rather, such paths are > temporarily treated like multipath members. If no additional paths > are detected after a certain time, the paths are re-added to the > system as non-multipath. This needs support by the udev rules, to > be added in a follow-up patch. > > If a multipath map is successfully successfully created, and paths are > in waiting state, trigger path uevents to update their status. > > Signed-off-by: Martin Wilck > --- > libmultipath/configure.c | 15 ++++++++++++--- > libmultipath/dict.c | 1 + > multipath/multipath.conf.5 | 13 +++++++++++++ > 3 files changed, 26 insertions(+), 3 deletions(-) > > diff --git a/libmultipath/configure.c b/libmultipath/configure.c > index 9aa3d21..17c2fa1 100644 > --- a/libmultipath/configure.c > +++ b/libmultipath/configure.c > @@ -12,6 +12,7 @@ > #include > #include > #include > +#include > #include > #include > #include "mpath_cmd.h" > @@ -476,9 +477,17 @@ trigger_paths_udev_change(struct multipath *mpp, bool is_mpath) > env = udev_device_get_property_value( > pp->udev, "DM_MULTIPATH_DEVICE_PATH"); > > - if (is_mpath && env != NULL && !strcmp(env, "1")) > - continue; > - else if (!is_mpath && If DM_MULTIPATH_DEVICE_PATH=1 then there has already been a uevent where udev recognized that the device should be claimed. Wouldn't udev have stopped the timer then? I don't see why this is necessary. > + if (is_mpath && env != NULL && !strcmp(env, "1")) { > + /* > + * If FIND_MULTIPATHS_WAIT_UNTIL is not "0", > + * path is in "maybe" state and timer is running > + * Send uevent now (see multipath.rules). > + */ > + env = udev_device_get_property_value( > + pp->udev, "FIND_MULTIPATHS_WAIT_UNTIL"); > + if (env == NULL || !strcmp(env, "0")) > + continue; > + } else if (!is_mpath && > (env == NULL || !strcmp(env, "0"))) > continue; > > diff --git a/libmultipath/dict.c b/libmultipath/dict.c > index 4be808d..8a18b1f 100644 > --- a/libmultipath/dict.c > +++ b/libmultipath/dict.c > @@ -239,6 +239,7 @@ static const char *find_multipaths_optvals[] = { > [FIND_MULTIPATHS_ON] = "on", > [FIND_MULTIPATHS_STRICT] = "strict", > [FIND_MULTIPATHS_GREEDY] = "greedy", > + [FIND_MULTIPATHS_SMART] = "smart", > }; > > static int > diff --git a/multipath/multipath.conf.5 b/multipath/multipath.conf.5 > index 94c419a..641ba43 100644 > --- a/multipath/multipath.conf.5 > +++ b/multipath/multipath.conf.5 > @@ -978,6 +978,19 @@ with the same WWID have been detected. > Both multipathd and multipath treat every non-blacklisted device as multipath > device path. > .TP > +.I smart > +This differs from \fIfind_multipaths yes\fR only in > +the way it treats new devices for which only one path has been > +detected yet. When such a device is first encounted in udev rules, it is > +treated as a multipath device. multipathd waits whether additional paths with > +the same WWID appears. If that happens, it sets up a multipath map. If it > +doesn\'t happen until a > +timeout expires, or if setting up the map fails, a new uevent is triggered for > +the device; at second encounter in the udev rules, the device will be treated > +as non-multipath and passed on to upper layers. > +\fBNote:\fR this may cause delays during device detection if > +there are single-path devices which aren\'t blacklisted. > +.TP > The default is: \fBstrict\fR > .RE > . > -- > 2.16.1