* mdadm: ARRAY <ignore> lines not correctly handled
@ 2012-11-11 8:42 Mike Frysinger
2012-11-22 6:05 ` NeilBrown
0 siblings, 1 reply; 2+ messages in thread
From: Mike Frysinger @ 2012-11-11 8:42 UTC (permalink / raw)
To: linux-raid
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the mdadm.conf man page states:
The ARRAY lines identify actual arrays. The second word on the line may be
the name of the device where the array is normally assembled, [...].
Alternately the word <ignore> (complete with angle brackets) can be given in
which case any array which matches the rest of the line will never be
automatically assembled.
so let's say i have a raid that looks like:
/dev/md0:
Version : 1.2
Creation Time : Wed Oct 31 16:05:49 2012
Raid Level : raid6
Array Size : 1953522688 (1863.02 GiB 2000.41 GB)
Used Dev Size : 976761344 (931.51 GiB 1000.20 GB)
Raid Devices : 4
Total Devices : 4
Persistence : Superblock is persistent
Update Time : Sun Nov 11 03:35:26 2012
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 512K
Name : vapier:0 (local to host vapier)
UUID : 51b812dc:094ea54b:f8f7b331:9982b16c
Events : 112048
Number Major Minor RaidDevice State
0 8 32 0 active sync /dev/sdc
1 8 0 1 active sync /dev/sda
4 8 16 2 active sync /dev/sdb
5 8 64 3 active sync /dev/sde
the man page says i should be able to prevent this from being auto-assembled
via `mdamd -As` by doing something like:
ARRAY <ignore> uuid=51b812dc:094ea54b:f8f7b331:9982b16c
or perhaps:
DEVICE /dev/sd[abce]
ARRAY <ignore> devices=/dev/sda,/dev/sdb,/dev/sde,/dev/sdc
unfortunately, this turns out to not be the case. mdadm goes ahead and auto-
assembles things anyways. looking at the code, it seems that it's due to the
code falling back if nothing was detected:
mdadm.c
...
do {
failures = 0;
successes = 0;
rv = 0;
for (a = array_list; a ; a = a->next) {
int r;
if (a->assembled)
continue;
if (a->devname &&
strcasecmp(a->devname, "<ignore>") == 0)
continue;
r = Assemble(ss, a->devname,
a, NULL, c);
if (r == 0) {
a->assembled = 1;
successes++;
} else
failures++;
rv |= r;
cnt++;
}
} while (failures && successes);
if (c->homehost && cnt == 0) {
/* Maybe we can auto-assemble something.
* Repeatedly call Assemble in auto-assemble mode
* until it fails
*/
int rv2;
int acnt;
ident->autof = c->autof;
do {
struct mddev_dev *devlist = conf_get_devs();
acnt = 0;
do {
rv2 = Assemble(ss, NULL,
ident,
devlist, c);
...
the idea is to be able to have a system with multiple raids (some of which are
dormant/backups), blacklist the ones that you want to keep idle, and bring
online all the rest.
-mike
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: mdadm: ARRAY <ignore> lines not correctly handled
2012-11-11 8:42 mdadm: ARRAY <ignore> lines not correctly handled Mike Frysinger
@ 2012-11-22 6:05 ` NeilBrown
0 siblings, 0 replies; 2+ messages in thread
From: NeilBrown @ 2012-11-22 6:05 UTC (permalink / raw)
To: Mike Frysinger; +Cc: linux-raid
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On Sun, 11 Nov 2012 03:42:35 -0500 Mike Frysinger <vapier@gentoo.org> wrote:
> the mdadm.conf man page states:
> The ARRAY lines identify actual arrays. The second word on the line may be
> the name of the device where the array is normally assembled, [...].
> Alternately the word <ignore> (complete with angle brackets) can be given in
> which case any array which matches the rest of the line will never be
> automatically assembled.
>
> so let's say i have a raid that looks like:
> /dev/md0:
> Version : 1.2
> Creation Time : Wed Oct 31 16:05:49 2012
> Raid Level : raid6
> Array Size : 1953522688 (1863.02 GiB 2000.41 GB)
> Used Dev Size : 976761344 (931.51 GiB 1000.20 GB)
> Raid Devices : 4
> Total Devices : 4
> Persistence : Superblock is persistent
>
> Update Time : Sun Nov 11 03:35:26 2012
> State : clean
> Active Devices : 4
> Working Devices : 4
> Failed Devices : 0
> Spare Devices : 0
>
> Layout : left-symmetric
> Chunk Size : 512K
>
> Name : vapier:0 (local to host vapier)
> UUID : 51b812dc:094ea54b:f8f7b331:9982b16c
> Events : 112048
>
> Number Major Minor RaidDevice State
> 0 8 32 0 active sync /dev/sdc
> 1 8 0 1 active sync /dev/sda
> 4 8 16 2 active sync /dev/sdb
> 5 8 64 3 active sync /dev/sde
>
> the man page says i should be able to prevent this from being auto-assembled
> via `mdamd -As` by doing something like:
> ARRAY <ignore> uuid=51b812dc:094ea54b:f8f7b331:9982b16c
>
> or perhaps:
> DEVICE /dev/sd[abce]
> ARRAY <ignore> devices=/dev/sda,/dev/sdb,/dev/sde,/dev/sdc
>
> unfortunately, this turns out to not be the case. mdadm goes ahead and auto-
> assembles things anyways. looking at the code, it seems that it's due to the
> code falling back if nothing was detected:
> mdadm.c
> ...
> do {
> failures = 0;
> successes = 0;
> rv = 0;
> for (a = array_list; a ; a = a->next) {
> int r;
> if (a->assembled)
> continue;
> if (a->devname &&
> strcasecmp(a->devname, "<ignore>") == 0)
> continue;
>
> r = Assemble(ss, a->devname,
> a, NULL, c);
> if (r == 0) {
> a->assembled = 1;
> successes++;
> } else
> failures++;
> rv |= r;
> cnt++;
> }
> } while (failures && successes);
> if (c->homehost && cnt == 0) {
> /* Maybe we can auto-assemble something.
> * Repeatedly call Assemble in auto-assemble mode
> * until it fails
> */
> int rv2;
> int acnt;
> ident->autof = c->autof;
> do {
> struct mddev_dev *devlist = conf_get_devs();
> acnt = 0;
> do {
> rv2 = Assemble(ss, NULL,
> ident,
> devlist, c);
> ...
>
> the idea is to be able to have a system with multiple raids (some of which are
> dormant/backups), blacklist the ones that you want to keep idle, and bring
> online all the rest.
> -mike
Thanks for the report.
Fixed by the following patch.
Thanks,
NeilBrown
From 66eb2c93a619eb1d79dc653fd91add159aa3d1ff Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Thu, 22 Nov 2012 17:04:20 +1100
Subject: [PATCH] Assemble: ensure that <ignore>d arrays are not
auto-assembled.
It isn't enough to simply not assemble arrays found to be called
<ignore>, as the final stage of auto-assemble doesn't check for names
in mdadm.conf.
So add a check to Assemble, similar to the check in Incremental()
Reported-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/Assemble.c b/Assemble.c
index c2fa096..9ef1bf0 100644
--- a/Assemble.c
+++ b/Assemble.c
@@ -362,6 +362,8 @@ static int select_devices(struct mddev_dev *devlist,
tmpdev = NULL;
goto loop;
} else {
+ int rv = 0;
+ struct mddev_ident *match;
content = *contentp;
tst->ss->getinfo_super(tst, content, NULL);
@@ -370,7 +372,20 @@ static int select_devices(struct mddev_dev *devlist,
c->homehost, c->update,
report_missmatch ? devname : NULL))
goto loop;
-
+
+ match = conf_match(tst, content, devname,
+ report_missmatch ? c->verbose : -1,
+ &rv);
+ if (!match && rv == 2)
+ goto loop;
+ if (match && match->devname &&
+ strcasecmp(match->devname, "<ignore>") == 0) {
+ if (report_missmatch)
+ pr_err("%s is a member of an explicitly ignored array\n",
+ devname);
+ goto loop;
+ }
+
/* should be safe to try an exclusive open now, we
* have rejected anything that some other mdadm might
* be looking at
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