[PATCH 2/2] ocfs2: Implement group add for online resize

This patch adds the ability for a userspace program to request that a
properly formatted cluster group be added to the main allocation bitmap for
an Ocfs2 file system. The request is made via an ioctl, OCFS2_IOC_GROUP_ADD.
On a high level, this is similar to ext3, but we use a different ioctl as
the structure which has to be passed through is different.

During an online resize, tunefs.ocfs2 will format any new cluster groups
which must be added to complete the resize, and call OCFS2_IOC_GROUP_ADD on
each one. Kernel verifies that the core cluster group information is valid
and then does the work of linking it into the global allocation bitmap.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index 19ac421b..4255517 100644
--- a/fs/ocfs2/ocfs2_fs.h
+++ b/fs/ocfs2/ocfs2_fs.h
@@ -231,7 +231,19 @@ struct ocfs2_space_resv {
 #define OCFS2_IOC_RESVSP64	_IOW ('X', 42, struct ocfs2_space_resv)
 #define OCFS2_IOC_UNRESVSP64	_IOW ('X', 43, struct ocfs2_space_resv)
 
+/* Used to pass group descriptor data when online resize is done */
+struct ocfs2_new_group_input {
+	__u64 group;		/* Group descriptor's blkno. */
+	__u32 clusters;		/* Total number of clusters in this group */
+	__u32 frees;		/* Total free clusters in this group */
+	__u16 chain;		/* Chain for this group */
+	__u16 reserved1;
+	__u32 reserved2;
+};
+
 #define OCFS2_IOC_GROUP_EXTEND	_IOW('o', 1, int)
+#define OCFS2_IOC_GROUP_ADD	_IOW('o', 2,struct ocfs2_new_group_input)
+#define OCFS2_IOC_GROUP_ADD64	_IOW('o', 3,struct ocfs2_new_group_input)
 
 /*
  * Journal Flags (ocfs2_dinode.id1.journal1.i_flags)