commit fafdd2bf2638157670f28462b641150d16dbaeca
author Richard Weinberger <richard@nod.at> Mon Nov 24 22:30:09 2014 +0100
committer Richard Weinberger <richard@nod.at> Wed Jan 28 15:57:04 2015 +0100
tree 717b6e07e8018eec9e6ac3e5ead6dedffbf4799c
parent 346be9bc802ddbaf7ce2ad35145d1ddfba376594

UBI: Implement UBI_METAONLY

UBI_METAONLY is a new open mode for UBI volumes, it indicates
that only meta data is being changed.
Meta data in terms of UBI volumes means data which is stored in the
UBI volume table but not on the volume itself.
While it does not interfere with UBI_READONLY and UBI_READWRITE
it is not allowed to use UBI_METAONLY together with UBI_EXCLUSIVE.

Cc: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Cc: Andrew Murray <amurray@embedded-bits.co.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
Tested-by: Guido Martínez <guido@vanguardiasur.com.ar>
Reviewed-by: Guido Martínez <guido@vanguardiasur.com.ar>
Tested-by: Christoph Fritz <chf.fritz@googlemail.com>
Tested-by: Andrew Murray <amurray@embedded-bits.co.uk>

drivers/mtd/ubi/cdev.c

diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
index 3410ea81..f5c715c 100644
--- a/drivers/mtd/ubi/cdev.c
+++ b/drivers/mtd/ubi/cdev.c
@@ -61,13 +61,13 @@
 	struct ubi_volume *vol = desc->vol;
 
 	spin_lock(&vol->ubi->volumes_lock);
-	users = vol->readers + vol->writers + vol->exclusive;
+	users = vol->readers + vol->writers + vol->exclusive + vol->metaonly;
 	ubi_assert(users > 0);
 	if (users > 1) {
 		ubi_err(ubi, "%d users for volume %d", users, vol->vol_id);
 		err = -EBUSY;
 	} else {
-		vol->readers = vol->writers = 0;
+		vol->readers = vol->writers = vol->metaonly = 0;
 		vol->exclusive = 1;
 		err = desc->mode;
 		desc->mode = UBI_EXCLUSIVE;
@@ -87,13 +87,15 @@
 	struct ubi_volume *vol = desc->vol;
 
 	spin_lock(&vol->ubi->volumes_lock);
-	ubi_assert(vol->readers == 0 && vol->writers == 0);
+	ubi_assert(vol->readers == 0 && vol->writers == 0 && vol->metaonly == 0);
 	ubi_assert(vol->exclusive == 1 && desc->mode == UBI_EXCLUSIVE);
 	vol->exclusive = 0;
 	if (mode == UBI_READONLY)
 		vol->readers = 1;
 	else if (mode == UBI_READWRITE)
 		vol->writers = 1;
+	else if (mode == UBI_METAONLY)
+		vol->metaonly = 1;
 	else
 		vol->exclusive = 1;
 	spin_unlock(&vol->ubi->volumes_lock);