ocfs2: make room for unwritten extents flag
Due to the size of our group bitmaps, we'll never have a leaf node extent
record with more than 16 bits worth of clusters. Split e_clusters up so that
leaf nodes can get a flags field where we can mark unwritten extents.
Interior nodes whose length references all the child nodes beneath it can't
split their e_clusters field, so we use a union to preserve sizing there.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index f010197..7130647 100644
--- a/fs/ocfs2/ocfs2_fs.h
+++ b/fs/ocfs2/ocfs2_fs.h
@@ -156,6 +156,12 @@
#define OCFS2_FL_MODIFIABLE (0x000100FF) /* User modifiable flags */
/*
+ * Extent record flags (e_node.leaf.flags)
+ */
+#define OCFS2_EXT_UNWRITTEN (0x01) /* Extent is allocated but
+ * unwritten */
+
+/*
* ioctl commands
*/
#define OCFS2_IOC_GETFLAGS _IOR('f', 1, long)
@@ -283,10 +289,21 @@
/*
* On disk extent record for OCFS2
* It describes a range of clusters on disk.
+ *
+ * Length fields are divided into interior and leaf node versions.
+ * This leaves room for a flags field (OCFS2_EXT_*) in the leaf nodes.
*/
struct ocfs2_extent_rec {
/*00*/ __le32 e_cpos; /* Offset into the file, in clusters */
- __le32 e_clusters; /* Clusters covered by this extent */
+ union {
+ __le32 e_int_clusters; /* Clusters covered by all children */
+ struct {
+ __le16 e_leaf_clusters; /* Clusters covered by this
+ extent */
+ __u8 e_reserved1;
+ __u8 e_flags; /* Extent flags */
+ };
+ };
__le64 e_blkno; /* Physical disk offset, in blocks */
/*10*/
};