pvcreate fails on a software RAID metadisk

Hi,

I'm trying to set up lvm 1.01rc4 under a 2.4.10 kernel. I'm getting an error when I try to use pvcreate on a software RAID metadisk. From the '-v' output of pvcreate, it appears that pvcreate thinks my metadisk is zero-length.

Here's an example:

root@tik-tok:~# pvcreate /dev/md7
pvcreate -- ERROR "parameter error" setting up  physical volume "/dev/md7"

root@tik-tok:~# pvcreate -v /dev/md7
pvcreate -- locking logical volume manager
pvcreate -- checking physical volume name "/dev/md7"
pvcreate -- getting physical volume size
pvcreate -- checking partition type
pvcreate -- creating new physical volume
pvcreate -- setting up physical volume for /dev/md7 with 0 sectors
pvcreate -- ERROR "parameter error" setting up  physical volume "/dev/md7"

root@tik-tok:~# pvcreate --version
pvcreate: Logical Volume Manager 1.0.1-rc4
Heinz Mauelshagen, Sistina Software  03/10/2001 (IOP 10)
root@tik-tok:~# cat /proc/mdstat | grep -A2 md7
md7 : active raid5 sde7[4] sdd7[3] sdc7[2] sdb7[1] sda7[0]
      24575488 blocks level 5, 128k chunk, algorithm 0 [5/5] [UUUUU]

root@tik-tok:~# grep md7 /proc/partitions
   9     7   24575488 md7

Any tips on what might be going on here would be appreciated...

Thanks,
Bill Ellis

Hi again,

Some more playing around led me to discover that 'lvmdiskscan' is also not recognizing my software RAID metadisks correctly. Here's what I think are the relevant portions of the ~5600 lines of output from the 'lvmdiskscan -d -v' command:

<1> lvm_dir_cache -- CALLED
<22> lvm_add_dir_cache -- CALLED with /dev/md3
...
<22> lvm_add_dir_cache -- CALLED with /dev/md7
<333> lvm_check_dev -- CALLED
<4444> lvm_check_partitioned_dev -- CALLED
<55555> lvm_get_device_type called
<55555> lvm_get_device_type leaving with 2
<4444> lvm_check_partitioned_dev -- LEAVING with ret: TRUE <333> lvm_check_dev -- LEAVING with ret: 1
<22> lvm_add_dir_cache -- LEAVING with ret: ADDED
...
<1> pv_get_size -- CALLED with /dev/md7 and 0xbffff8ac
<22> lvm_dir_cache -- CALLED
<22> lvm_dir_cache -- LEAVING with ret: 50
<22> lvm_dir_cache_find -- CALLED with /dev/md7
<333> pv_check_name -- CALLED with "/dev/md7"
<4444> lvm_check_chars -- CALLED with name: "/dev/md7" <4444> lvm_check_chars -- LEAVING with ret: 0
<4444> lvm_check_dev -- CALLED
<55555> lvm_check_partitioned_dev -- CALLED
<666666> lvm_get_device_type called
<666666> lvm_get_device_type leaving with 2
<55555> lvm_check_partitioned_dev -- LEAVING with ret: TRUE <4444> lvm_check_dev -- LEAVING with ret: 1
<333> pv_check_name -- LEAVING with ret: 0
<333> lvm_dir_cache -- CALLED
<333> lvm_dir_cache -- LEAVING with ret: 50
<22> lvm_dir_cache_find -- LEAVING with entry: 4
<22> lvm_check_partitioned_dev -- CALLED
<333> lvm_get_device_type called
<333> lvm_get_device_type leaving with 2
<22> lvm_check_partitioned_dev -- LEAVING with ret: TRUE <22> lvm_partition_count -- CALLED for 0x907
<333> lvm_get_device_type called
<333> lvm_get_device_type leaving with 2
<22> lvm_partition_count -- LEAVING with ret: 16
<1> pv_get_size -- LEAVING with ret: 0
...
lvmdiskscan -- reading all disks / partitions (this may take a while...) lvmdiskscan -- filling directory cache...
lvmdiskscan -- walking through all found disks / partitions

lvmdiskscan -- /dev/md3  [             0] Primary   [0x07]
lvmdiskscan -- /dev/md4  [             0] Primary   [0x07]
lvmdiskscan -- /dev/md5  [             0] Extended  [0x07]
lvmdiskscan -- /dev/md6  [             0] Extended  [0x07]
lvmdiskscan -- /dev/md7  [             0] Extended  [0x07]

lvmdiskscan -- /dev/sda1 [ 19.98 MB] Primary LINUX native partition
[0x83]
lvmdiskscan -- /dev/sda2 [ 80.00 MB] Primary LINUX swap partition [0x82]

lvmdiskscan -- /dev/sda3 [ 5.76 GB] Primary [0xFD]
lvmdiskscan -- /dev/sda4 [ 28.34 GB] DOS extended partition [0x05]

lvmdiskscan -- /dev/sda5 [       5.86 GB] Extended  [0xFD]
lvmdiskscan -- /dev/sda6 [       5.86 GB] Extended  [0xFD]
lvmdiskscan -- /dev/sda7 [       5.86 GB] Extended  [0xFD]
lvmdiskscan -- /dev/sda8 [       5.86 GB] Extended LVM partition [0x8E]

lvmdiskscan -- /dev/sdb1 [ 19.98 MB] Primary LINUX native partition
[0x83]
lvmdiskscan -- /dev/sdb2 [ 80.00 MB] Primary LINUX swap partition [0x82]

lvmdiskscan -- /dev/sdb3 [ 5.76 GB] Primary [0xFD]
lvmdiskscan -- /dev/sdb4 [ 28.34 GB] DOS extended partition [0x05]

lvmdiskscan -- /dev/sdb5 [       5.86 GB] Extended  [0xFD]
lvmdiskscan -- /dev/sdb6 [       5.86 GB] Extended  [0xFD]
lvmdiskscan -- /dev/sdb7 [       5.86 GB] Extended  [0xFD]
lvmdiskscan -- /dev/sdb8 [       5.86 GB] Extended LVM partition [0x8E]

lvmdiskscan -- /dev/sdc1 [ 19.98 MB] Primary LINUX native partition
[0x83]
lvmdiskscan -- /dev/sdc2 [ 80.00 MB] Primary LINUX swap partition [0x82]

lvmdiskscan -- /dev/sdc3 [ 5.76 GB] Primary [0xFD]
lvmdiskscan -- /dev/sdc4 [ 28.34 GB] DOS extended partition [0x05]

lvmdiskscan -- /dev/sdc5 [       5.86 GB] Extended  [0xFD]
lvmdiskscan -- /dev/sdc6 [       5.86 GB] Extended  [0xFD]
lvmdiskscan -- /dev/sdc7 [       5.86 GB] Extended  [0xFD]
lvmdiskscan -- /dev/sdc8 [       5.86 GB] Extended LINUX native partition

[0x83]
lvmdiskscan -- /dev/sdd1 [ 19.98 MB] Primary LINUX native partition
[0x83]
lvmdiskscan -- /dev/sdd2 [ 80.00 MB] Primary LINUX swap partition [0x82]

lvmdiskscan -- /dev/sdd3 [ 5.76 GB] Primary [0xFD]
lvmdiskscan -- /dev/sdd4 [ 28.34 GB] DOS extended partition [0x05]

lvmdiskscan -- /dev/sdd5 [       5.86 GB] Extended  [0xFD]
lvmdiskscan -- /dev/sdd6 [       5.86 GB] Extended  [0xFD]
lvmdiskscan -- /dev/sdd7 [       5.86 GB] Extended  [0xFD]
lvmdiskscan -- /dev/sdd8 [       5.86 GB] Extended LINUX native partition

[0x83]
lvmdiskscan -- /dev/sde1 [ 19.98 MB] Primary LINUX native partition
[0x83]
lvmdiskscan -- /dev/sde2 [ 80.00 MB] Primary LINUX swap partition [0x82]

lvmdiskscan -- /dev/sde3 [ 5.76 GB] Primary LINUX native partition
[0x83]
lvmdiskscan -- /dev/sde4 [ 28.34 GB] DOS extended partition [0x05]

lvmdiskscan -- /dev/sde5 [       5.86 GB] Extended  [0xFD]
lvmdiskscan -- /dev/sde6 [       5.86 GB] Extended  [0xFD]
lvmdiskscan -- /dev/sde7 [       5.86 GB] Extended  [0xFD]
lvmdiskscan -- /dev/sde8 [       5.86 GB] Extended LINUX native partition

[0x83]
lvmdiskscan -- 5 disks
lvmdiskscan -- 0 whole disks
lvmdiskscan -- 0 loop devices
lvmdiskscan -- 0 multiple devices
lvmdiskscan -- 0 network block devices
lvmdiskscan -- 45 partitions
lvmdiskscan -- 2 LVM physical volume partitions

Again, if anyone can give me any leads as to what might be going wrong here, I'd appreciate it. Also, if there is any more information I can provide on this matter, just let me know...

Thanks,
Bill

This is a problem - MD devices are not partitioned. Have a look at this function to see why it thinks so.

A pet peeve of mine - we shouldn't have to call this function twice (probably we should assume that anything that is in the dir cache is a valid device (and check devices one time when they are added)).

I suspect this is just an artifact of the code thinking it is a partitioned device.

Cheers, Andreas
--
Andreas Dilger \ "If a man ate a pound of pasta and a pound of antipasto,
\ would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/ -- Dogbert

no this should be normal
i believe the problem lies somewhere else in the damned cache i tested it on one of my systems, i have 4 disks and 4 md devices there md/0 is not detected
md/1 to md/3 are
and lvmdiskscan says i have 5 disks and 3 md devices.

look in http://www.comedia.it/bluca/lvm/
you will find lvmdiskscan output for
md0 (not working)
md1 (working)
and a diff file between the two that may help debugging basically pv_read is called for md/1 and not for md/0

(i was using current cvs)

i will look further into this problem since i have to build a new lvm over md but if someone else looks in it the better.

L.

Luca Berra -- [email protected]
        Communication Media & Services S.r.l.
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Well, a quick look into lvm_check_partitioned_dev.c makes me think the whole thing is broken. lvm_check_partitioned_dev() is only checking if this is a block device (via lvm_get_device_type()). If you look at pv_get_size(), it is depending on this to return FALSE if it is not a partitioned device type (which it never does now).

Running "cvs annotate tools/lib/lvm_check_partitioned_dev.c" shows that "akergon" is in the hot seat now (having re-written 90% of this file). What is probably needed is to move the unpartitioned devices code out from lvm_check_dev() into another helper function, which can be called from lvm_check_dev(), lvm_check_partitioned_dev(), lvm_partition_count(), and lvm_check_whole_disk_dev().

Then lvm_check_partitioned_dev() can return FALSE if it is a whole disk device, lvm_check_whole_disk_dev() will return TRUE, lvm_partition_count() should probably return 1 for a whole disk device.

Cheers, Andreas
--
Andreas Dilger \ "If a man ate a pound of pasta and a pound of antipasto,
\ would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/ -- Dogbert

I experienced something similar with 1.0.1-rc2 (see the [linux-lvm] Root + Software RAID 1 in partition + LVM + Reiserfs) thread.
From the code in pv_check_partitioned_dev it seems to me you run into exactly the same problem.

I did a quick and dirty patch which fixed it for me.
Please be aware: I am new to this list, new to linux LVM...
I know the patch will prevent you from using any partitioned MD device in LVM. I have no idea of further implications.
------------------------------------------------------------
diff -ru 1.0.1-rc2/tools/lib/lvm_check_partitioned_dev.c slp-1.0.1-rc2/tools/lib/lvm_check_partitioned_dev.c
--- 1.0.1-rc2/tools/lib/lvm_check_partitioned_dev.c Mon Aug 20 17:17:56 2001
+++ slp-1.0.1-rc2/tools/lib/lvm_check_partitioned_dev.c Thu Oct 4 14:47:37
2001
@@ -55,6 +55,8 @@
switch (lvm_get_device_type(st_rdev)) {
case LVM_DEVICE_TYPE_INVALID:
break;
+ case 2: /* YAL: MD device on partition. Won't partition it. */
+ break;
default:
ret = TRUE;
}
------------------------------------------------------------

Please wait until more experienced people comment this patch before using it.

Yves

Yves, thanks this seems to have fixed this, i still agree with Andreas that lvm_check_partitioned_dev should be checked.
i wuld use LVM_DEVICE_TYPE_MD instead of 2 in the patch
as for partitioned md device i believe the major is different from 9, but i would not suggest using them with lvm anyway.

patch with my mod follows for the lazy,
pleas check it in cvs for the time being.

@@ -55,6 +55,8 @@
 	switch (lvm_get_device_type(st_rdev)) {
 	case LVM_DEVICE_TYPE_INVALID:
 	    break;
+	case LVM_DEVICE_TYPE_MD:
+	    break;
 	default:
 	    ret = TRUE;
 	}

Luca Berra -- [email protected]
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