dm: add name and uuid to sysfs
Implement simple read-only sysfs entry for device-mapper block device.
This patch adds a simple sysfs directory named "dm" under block device
properties and implements
- name attribute (string containing mapped device name)
- uuid attribute (string containing UUID, or empty string if not set)
The kobject is embedded in mapped_device struct, so no additional
memory allocation is needed for initializing sysfs entry.
During the processing of sysfs attribute we need to lock mapped device
which is done by a new function dm_get_from_kobj, which returns the md
associated with kobject and increases the usage count.
Each 'show attribute' function is responsible for its own locking.
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 9f9aa64..51ba1db 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1,6 +1,6 @@
/*
* Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
- * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
@@ -167,6 +167,9 @@
/* forced geometry settings */
struct hd_geometry geometry;
+
+ /* sysfs handle */
+ struct kobject kobj;
};
#define MIN_IOS 256
@@ -1285,6 +1288,8 @@
if (!md)
return -ENXIO;
+ dm_sysfs_init(md);
+
*result = md;
return 0;
}
@@ -1360,6 +1365,7 @@
dm_table_presuspend_targets(map);
dm_table_postsuspend_targets(map);
}
+ dm_sysfs_exit(md);
dm_table_put(map);
__unbind(md);
free_dev(md);
@@ -1699,6 +1705,27 @@
return md->disk;
}
+struct kobject *dm_kobject(struct mapped_device *md)
+{
+ return &md->kobj;
+}
+
+/*
+ * struct mapped_device should not be exported outside of dm.c
+ * so use this check to verify that kobj is part of md structure
+ */
+struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
+{
+ struct mapped_device *md;
+
+ md = container_of(kobj, struct mapped_device, kobj);
+ if (&md->kobj != kobj)
+ return NULL;
+
+ dm_get(md);
+ return md;
+}
+
int dm_suspended(struct mapped_device *md)
{
return test_bit(DMF_SUSPENDED, &md->flags);