From: Hannes Reinecke <hare@xxxxxxx>
Subject: Allow switch device-mapper tables to READ-WRITE
Switching a device-mapper table to READ-ONLY works quite well, but
we can't switch back to READ-WRITE as this change will be masked out.
So get rid of this masking and use the flags directly.
And implement a fallback to automatically switch to read-only.
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
Signed-off-by: Nikanth Karthikesan <knikanth@xxxxxxx>
---
Index: linux-2.6-dm/drivers/md/dm-table.c
===================================================================
--- linux-2.6-dm.orig/drivers/md/dm-table.c
+++ linux-2.6-dm/drivers/md/dm-table.c
@@ -403,10 +403,15 @@ static int upgrade_mode(struct dm_dev_in
dd_new = dd_old = *dd;
- dd_new.dm_dev.mode |= new_mode;
+ dd_new.dm_dev.mode = new_mode;
dd_new.dm_dev.bdev = NULL;
r = open_dev(&dd_new, dd->dm_dev.bdev->bd_dev, md);
+ if (r == -EROFS) {
+ dd_new.dm_dev.mode &= ~FMODE_WRITE;
+ r = open_dev(&dd_new, dd->dm_dev.bdev->bd_dev, md);
+ }
+
if (r)
return r;
@@ -473,7 +478,7 @@ static int __table_get_device(struct dm_
atomic_set(&dd->count, 0);
list_add(&dd->list, &t->devices);
- } else if (dd->dm_dev.mode != (mode | dd->dm_dev.mode)) {
+ } else if (dd->dm_dev.mode != mode) {
r = upgrade_mode(dd, mode, t->md);
if (r)
return r;
--
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