[dm-devel] [PATCH] [RFC] switch DM tables to readonly automatically

Wed Apr 30 05:43:27 UTC 2008

Hi,
Though the patch creates read-only device mappings, the READONLY status is not reflected on device mapper multipath devices.
Example: open with O_RDWR flag succeeds for read-only mpath devices, and write fails with "Operation not permitted" error.

Attached patch would fix this.

Thanks,
Vijay

-----Original Message-----
From: dm-devel-bounces at redhat.com [mailto:dm-devel-bounces at redhat.com] On Behalf Of Hannes Reinecke
Sent: Friday, April 25, 2008 8:03 PM
To: device-mapper development
Subject: [dm-devel] [PATCH] [RFC] switch DM tables to readonly automatically

Hi all,

this patch switches the device-mapper table to read-only status automatically if one underlying device returns -EROFS.

Rationale:
Whenever a SCSI device is switched to read-only a table reload from multipath-tools fails, without any indication about the reason. And it's actually quite tricky to detect the read-only status from userland. And quite pointless, too, as the kernel already knows about it.

And we now can create tables for CD-ROMs, too, without having to use the '-r' flag to dmsetup ...

Christophe, this might also fix your problem.

As usual, comments etc are welcome.

Cheers,

Hannes
--
Dr. Hannes Reinecke                   zSeries & Storage
hare at suse.de                          +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)
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