Attachment 631760 Details for Bug 855398 – Fix for problem - awaiting review

[patch] Fix for problem - awaiting review

bz855398-lvm-remove-ignore_suspended_device-restriction-from-mirrors.patch (text/plain), 1.91 KB, created by Jonathan Earl Brassow on 2012-10-22 22:28:26 UTC

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Creator: Jonathan Earl Brassow

Created: 2012-10-22 22:28:26 UTC

Size: 1.91 KB

patch

obsolete

>cluser mirror:  Allow VGs to be built on cluster mirrors
>
>While it is possible to create VGs on top of cluster mirrors,
>it is currently worthless to do so because no LVs can be created.
>This is not a limitation of 'locking_type = 1' LVM.  IOW, you can
>happily stack a VG on top of a single machine LV of 'mirror'
>segment type.
>
>The disconnect comes because of the way 'ignore_suspended_devices'
>is set.  That is, it is not set during lvcreate/lvremove when
>running 'locking_type = 1' (i.e. single machine).  However, it is set
>- every time - when 'locking_type = 3' and the activation is sent
>through clvmd.
>
>'ignore_suspended_devices' is meant to avoid reading any DM device
>that is suspended.  However, a mirror device can block I/O for a couple
>reasons.  The first is because it is suspended.  The second is because
>it has a unaddressed device failure.  The first case would be already
>addressed by the generic rejection of all DM devices that are suspended.
>The second is not addressed at all by also rejecting mirror devices if
>'ignore_suspended_devices' is set.  Therefore, this chunk of code is
>pointless.  It also is the cause of not being able to use mirrors as
>a source for VG stacking.
>
>Index: lvm2/lib/activate/dev_manager.c
>===================================================================
>--- lvm2.orig/lib/activate/dev_manager.c
>+++ lvm2/lib/activate/dev_manager.c
>@@ -181,16 +181,10 @@ int device_is_usable(struct device *dev)
> 	}
> 
> 	/* FIXME Also check for mirror block_on_error and mpath no paths */
>-	/* For now, we exclude all mirrors */
>-
> 	do {
> 		next = dm_get_next_target(dmt, next, &start, &length,
> 					  &target_type, &params);
> 		/* Skip if target type doesn't match */
>-		if (target_type && !strcmp(target_type, "mirror") && ignore_suspended_devices()) {
>-			log_debug("%s: Mirror device %s not usable.", dev_name(dev), name);
>-			goto out;
>-		}
> 
> 		/*
> 		 * Snapshot origin could be sitting on top of a mirror which

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Attachments on bug 855398: 631760