[patch 42/56] md: Allow metadata_version to be updated for externally managed metadata.

Greg KH
2009-02-11T00:43:17Z

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2.6.27-stable review patch. If anyone has any objections, please let us know.
------------------

From: NeilBrown <neilb@suse.de>

commit ea43ddd8491feccf36267349748ea91b1194481e upstream.

For externally managed metadata, the 'metadata_version' sysfs
attribute is really just a channel for user-space programs to
communicate about how the array is being managed.
It can be useful for this to be changed while the array is active.

Normally changes to metadata_version are not permitted while the array
is active. Change that so that if the metadata is externally managed,
the metadata_version can be changed to a different flavour of external
management.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/md/md.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2960,7 +2960,13 @@ metadata_store(mddev_t *mddev, const cha
{
int major, minor;
char *e;
- if (!list_empty(&mddev->disks))
+ /* Changing the details of 'external' metadata is
+ * always permitted. Otherwise there must be
+ * no devices attached to the array.
+ */
+ if (mddev->external && strncmp(buf, "external:", 9) == 0)
+ ;
+ else if (!list_empty(&mddev->disks))
return -EBUSY;

if (cmd_match(buf, "none")) {