* Re: mdadm named array (metadata 1.2) and udev when assembling an array in initramfs
@ 2014-11-03 1:50 NeilBrown
2014-11-03 4:16 ` Stephen Kent
0 siblings, 1 reply; 6+ messages in thread
From: NeilBrown @ 2014-11-03 1:50 UTC (permalink / raw)
To: Stephen Kent; +Cc: linux RAID
[-- Attachment #1: Type: text/plain, Size: 1343 bytes --]
Hi Stephen,
thanks for the bug report.
This patch should fix it.
NeilBrown
From 628cdf19ea35daad22e409e51c0abc7ffb19d6aa Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Mon, 3 Nov 2014 12:49:05 +1100
Subject: [PATCH] Rebuildmap: strip local host name from device name.
When /run/mdadm/map is being rebuilt, e.g. by "mdadm -Ir",
if the device doesn't exist in /dev, we have to choose
a name.
Currently we don't strip the hostname which is wrong if
it is the local host.
Reported-by: Stephen Kent <smkent@smkent.net>
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/mapfile.c b/mapfile.c
index 4e7f24214b8a..41599df05f97 100644
--- a/mapfile.c
+++ b/mapfile.c
@@ -455,12 +455,19 @@ void RebuildMap(void)
sep = "";
}
}
- if (strchr(name, ':'))
- /* probably a uniquifying
+ if (strchr(name, ':')) {
+ /* Probably a uniquifying
* hostname prefix. Allow
- * without a suffix
+ * without a suffix, and strip
+ * hostname if it is us.
*/
+ if (homehost && unum == -1 &&
+ strncmp(name, homehost,
+ strlen(homehost)) == 0 &&
+ name[strlen(homehost)] == ':')
+ name += strlen(homehost)+1;
unum = -1;
+ }
while (conflict) {
if (unum >= 0)
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^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: mdadm named array (metadata 1.2) and udev when assembling an array in initramfs
2014-11-03 1:50 mdadm named array (metadata 1.2) and udev when assembling an array in initramfs NeilBrown
@ 2014-11-03 4:16 ` Stephen Kent
2014-11-03 5:43 ` NeilBrown
0 siblings, 1 reply; 6+ messages in thread
From: Stephen Kent @ 2014-11-03 4:16 UTC (permalink / raw)
To: NeilBrown; +Cc: linux RAID
On Sun, Nov 2, 2014 at 5:50 PM, NeilBrown <neilb@suse.de> wrote:
>
> Hi Stephen,
> thanks for the bug report.
> This patch should fix it.
>
> NeilBrown
>
> From 628cdf19ea35daad22e409e51c0abc7ffb19d6aa Mon Sep 17 00:00:00 2001
> From: NeilBrown <neilb@suse.de>
> Date: Mon, 3 Nov 2014 12:49:05 +1100
> Subject: [PATCH] Rebuildmap: strip local host name from device name.
>
> When /run/mdadm/map is being rebuilt, e.g. by "mdadm -Ir",
> if the device doesn't exist in /dev, we have to choose
> a name.
> Currently we don't strip the hostname which is wrong if
> it is the local host.
>
> Reported-by: Stephen Kent <smkent@smkent.net>
> Signed-off-by: NeilBrown <neilb@suse.de>
>
> diff --git a/mapfile.c b/mapfile.c
> index 4e7f24214b8a..41599df05f97 100644
> --- a/mapfile.c
> +++ b/mapfile.c
> @@ -455,12 +455,19 @@ void RebuildMap(void)
> sep = "";
> }
> }
> - if (strchr(name, ':'))
> - /* probably a uniquifying
> + if (strchr(name, ':')) {
> + /* Probably a uniquifying
> * hostname prefix. Allow
> - * without a suffix
> + * without a suffix, and strip
> + * hostname if it is us.
> */
> + if (homehost && unum == -1 &&
> + strncmp(name, homehost,
> + strlen(homehost)) == 0 &&
> + name[strlen(homehost)] == ':')
> + name += strlen(homehost)+1;
> unum = -1;
> + }
>
> while (conflict) {
> if (unum >= 0)
Your patch works for me! Thanks so much for taking a look.
Stephen
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: mdadm named array (metadata 1.2) and udev when assembling an array in initramfs
2014-11-03 4:16 ` Stephen Kent
@ 2014-11-03 5:43 ` NeilBrown
0 siblings, 0 replies; 6+ messages in thread
From: NeilBrown @ 2014-11-03 5:43 UTC (permalink / raw)
To: Stephen Kent; +Cc: linux RAID
[-- Attachment #1: Type: text/plain, Size: 2681 bytes --]
On Sun, 2 Nov 2014 20:16:34 -0800 Stephen Kent <smkent@smkent.net> wrote:
> On Sun, Nov 2, 2014 at 5:50 PM, NeilBrown <neilb@suse.de> wrote:
> >
> > Hi Stephen,
> > thanks for the bug report.
> > This patch should fix it.
> >
> > NeilBrown
> >
> > From 628cdf19ea35daad22e409e51c0abc7ffb19d6aa Mon Sep 17 00:00:00 2001
> > From: NeilBrown <neilb@suse.de>
> > Date: Mon, 3 Nov 2014 12:49:05 +1100
> > Subject: [PATCH] Rebuildmap: strip local host name from device name.
> >
> > When /run/mdadm/map is being rebuilt, e.g. by "mdadm -Ir",
> > if the device doesn't exist in /dev, we have to choose
> > a name.
> > Currently we don't strip the hostname which is wrong if
> > it is the local host.
> >
> > Reported-by: Stephen Kent <smkent@smkent.net>
> > Signed-off-by: NeilBrown <neilb@suse.de>
> >
> > diff --git a/mapfile.c b/mapfile.c
> > index 4e7f24214b8a..41599df05f97 100644
> > --- a/mapfile.c
> > +++ b/mapfile.c
> > @@ -455,12 +455,19 @@ void RebuildMap(void)
> > sep = "";
> > }
> > }
> > - if (strchr(name, ':'))
> > - /* probably a uniquifying
> > + if (strchr(name, ':')) {
> > + /* Probably a uniquifying
> > * hostname prefix. Allow
> > - * without a suffix
> > + * without a suffix, and strip
> > + * hostname if it is us.
> > */
> > + if (homehost && unum == -1 &&
> > + strncmp(name, homehost,
> > + strlen(homehost)) == 0 &&
> > + name[strlen(homehost)] == ':')
> > + name += strlen(homehost)+1;
> > unum = -1;
> > + }
> >
> > while (conflict) {
> > if (unum >= 0)
>
>
> Your patch works for me! Thanks so much for taking a look.
>
Great - thanks for the confirmation. It will be in the next release.
NeilBrown
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^ permalink raw reply [flat|nested] 6+ messages in thread
* mdadm named array (metadata 1.2) and udev when assembling an array in initramfs
@ 2014-11-01 18:53 Stephen Kent
2014-11-04 9:06 ` Michael Tokarev
0 siblings, 1 reply; 6+ messages in thread
From: Stephen Kent @ 2014-11-01 18:53 UTC (permalink / raw)
To: linux-raid
I have set up a machine to use an md array as the root device. I have
created the array with metadata type 1.2, name "root," on host
"optimus" (so the full metadata name is "optimus:root").
I'm using Gentoo Linux (kernel 3.16.5-gentoo), and previously I had no
initramfs so I wrote a short one to assemble the array. My initramfs
sets the hostname and runs "mdadm -As," which correctly auto-assembles
the root device array on /dev/md/root (even without an
/etc/mdadm.conf).
Once the initramfs script is finished, init starts which then starts
udev. Now, at this point the array is already assembled, but the
/dev/md/* name is lost (and so is /run/mdadm/map) since those files
were on the initramfs' tempfs root. udev creates a /dev/mdXXX node
(ex. /dev/md127) and then runs a rule to try to figure out the
/dev/md/* name, which should be /dev/md/root. The default udev rule
calls mdadm --detail --export /dev/md127, which should print
MD_DEVNAME=root for udev, but instead it prints
MD_DEVNAME=optimus:root, and the symlink in /dev/md gets created as
/dev/md/optimus:root.
I think this is a bug in mdadm, but I'm not sure how to dig into it. I
have made sure that my main OS init sets the hostname before starting
udev, and I have tried with and without "HOMEHOST optimus" in
/etc/mdadm.conf.
The workaround I am using right now is to define the array name
manually in /etc/mdadm.conf like this:
ARRAY /dev/md/root UUID=782a671c:e646f2d5:848baad0:5668ee84
This works by avoiding automatic name detection and using the defined
name (/dev/md/root), but it really seems that mdadm should know how to
determine MD_DEVNAME correctly for an already-started array if the
hostname (or homehost) is correctly set. Is this a bug in mdadm? If
so, is this the correct place to report it or is there a bug tracking
system I should use? I am using mdadm v3.3.1.
(Please cc me on replies as I am not currently subscribed to the
linux-raid list.)
Thanks,
Stephen
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: mdadm named array (metadata 1.2) and udev when assembling an array in initramfs
2014-11-01 18:53 Stephen Kent
@ 2014-11-04 9:06 ` Michael Tokarev
2014-11-04 18:17 ` Stephen Kent
0 siblings, 1 reply; 6+ messages in thread
From: Michael Tokarev @ 2014-11-04 9:06 UTC (permalink / raw)
To: Stephen Kent, linux-raid
01.11.2014 21:53, Stephen Kent wrote:
> I have set up a machine to use an md array as the root device. I have
> created the array with metadata type 1.2, name "root," on host
> "optimus" (so the full metadata name is "optimus:root").
>
> I'm using Gentoo Linux (kernel 3.16.5-gentoo), and previously I had no
> initramfs so I wrote a short one to assemble the array. My initramfs
> sets the hostname and runs "mdadm -As," which correctly auto-assembles
> the root device array on /dev/md/root (even without an
> /etc/mdadm.conf).
>
> Once the initramfs script is finished, init starts which then starts
> udev. Now, at this point the array is already assembled, but the
> /dev/md/* name is lost (and so is /run/mdadm/map) since those files
> were on the initramfs' tempfs root.
This is your problem. You should not lose neither /dev nor /run
when switching root. Usual thing to do is to mount tmpfs /dev and
tmpfs /run in initramfs and do mount --move /dev /root/dev (and
the same for /run) before switching root.
Thanks,
/mjt
> udev creates a /dev/mdXXX node
> (ex. /dev/md127) and then runs a rule to try to figure out the
> /dev/md/* name, which should be /dev/md/root. The default udev rule
> calls mdadm --detail --export /dev/md127, which should print
> MD_DEVNAME=root for udev, but instead it prints
> MD_DEVNAME=optimus:root, and the symlink in /dev/md gets created as
> /dev/md/optimus:root.
>
> I think this is a bug in mdadm, but I'm not sure how to dig into it. I
> have made sure that my main OS init sets the hostname before starting
> udev, and I have tried with and without "HOMEHOST optimus" in
> /etc/mdadm.conf.
>
> The workaround I am using right now is to define the array name
> manually in /etc/mdadm.conf like this:
>
> ARRAY /dev/md/root UUID=782a671c:e646f2d5:848baad0:5668ee84
>
> This works by avoiding automatic name detection and using the defined
> name (/dev/md/root), but it really seems that mdadm should know how to
> determine MD_DEVNAME correctly for an already-started array if the
> hostname (or homehost) is correctly set. Is this a bug in mdadm? If
> so, is this the correct place to report it or is there a bug tracking
> system I should use? I am using mdadm v3.3.1.
>
> (Please cc me on replies as I am not currently subscribed to the
> linux-raid list.)
>
> Thanks,
>
> Stephen
> --
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: mdadm named array (metadata 1.2) and udev when assembling an array in initramfs
2014-11-04 9:06 ` Michael Tokarev
@ 2014-11-04 18:17 ` Stephen Kent
0 siblings, 0 replies; 6+ messages in thread
From: Stephen Kent @ 2014-11-04 18:17 UTC (permalink / raw)
To: Michael Tokarev; +Cc: linux-raid
On Tue, Nov 4, 2014 at 1:06 AM, Michael Tokarev <mjt@tls.msk.ru> wrote:
>
> 01.11.2014 21:53, Stephen Kent wrote:
> > I have set up a machine to use an md array as the root device. I have
> > created the array with metadata type 1.2, name "root," on host
> > "optimus" (so the full metadata name is "optimus:root").
> >
> > I'm using Gentoo Linux (kernel 3.16.5-gentoo), and previously I had no
> > initramfs so I wrote a short one to assemble the array. My initramfs
> > sets the hostname and runs "mdadm -As," which correctly auto-assembles
> > the root device array on /dev/md/root (even without an
> > /etc/mdadm.conf).
> >
> > Once the initramfs script is finished, init starts which then starts
> > udev. Now, at this point the array is already assembled, but the
> > /dev/md/* name is lost (and so is /run/mdadm/map) since those files
> > were on the initramfs' tempfs root.
>
> This is your problem. You should not lose neither /dev nor /run
> when switching root. Usual thing to do is to mount tmpfs /dev and
> tmpfs /run in initramfs and do mount --move /dev /root/dev (and
> the same for /run) before switching root.
>
> Thanks,
>
> /mjt
Hm, interesting. I didn't realize a mount point could be moved, that's
good to know.
My initramfs is a short custom shell script that I wrote, basically
all it does is assemble the array and mount the root filesystem. I'm
not mounting a tmpfs and/or udev on /run and /dev, so unfortunately
there aren't any mount points to move to the target root mountpoint at
the end of init. /run and /dev are only mounted on my machine after
leaving the initramfs.
Fortunately, NeilBrown's patch works for me which solves the problem
and allows mdadm to work correctly with a minimal initramfs.
Stephen
^ permalink raw reply [flat|nested] 6+ messages in thread
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