Btrfs: add btrfs_scratch_superblock() function
This new function is used by the device replace procedure in
a later patch.
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 96bb2e4..6cd8a32 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5106,3 +5106,21 @@
stats->nr_items = BTRFS_DEV_STAT_VALUES_MAX;
return 0;
}
+
+int btrfs_scratch_superblock(struct btrfs_device *device)
+{
+ struct buffer_head *bh;
+ struct btrfs_super_block *disk_super;
+
+ bh = btrfs_read_dev_super(device->bdev);
+ if (!bh)
+ return -EINVAL;
+ disk_super = (struct btrfs_super_block *)bh->b_data;
+
+ memset(&disk_super->magic, 0, sizeof(disk_super->magic));
+ set_buffer_dirty(bh);
+ sync_dirty_buffer(bh);
+ brelse(bh);
+
+ return 0;
+}