1 files changed, 77 insertions, 2 deletions

diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index 3633edd3982f..52c426665154 100644
--- a/fs/ocfs2/ocfs2_fs.h
+++ b/fs/ocfs2/ocfs2_fs.h
@@ -88,7 +88,9 @@
 #define OCFS2_FEATURE_COMPAT_SUPP       OCFS2_FEATURE_COMPAT_BACKUP_SB
 #define OCFS2_FEATURE_INCOMPAT_SUPP     (OCFS2_FEATURE_INCOMPAT_LOCAL_MOUNT \
                                          | OCFS2_FEATURE_INCOMPAT_SPARSE_ALLOC \
-                                         | OCFS2_FEATURE_INCOMPAT_INLINE_DATA)
+                                         | OCFS2_FEATURE_INCOMPAT_INLINE_DATA \
+                                         | OCFS2_FEATURE_INCOMPAT_EXTENDED_SLOT_MAP \
+                                         | OCFS2_FEATURE_INCOMPAT_USERSPACE_STACK)
 #define OCFS2_FEATURE_RO_COMPAT_SUPP    OCFS2_FEATURE_RO_COMPAT_UNWRITTEN
 
 /*
@@ -125,6 +127,21 @@
 /* Support for data packed into inode blocks */
 #define OCFS2_FEATURE_INCOMPAT_INLINE_DATA      0x0040
 
+/* Support for the extended slot map */
+#define OCFS2_FEATURE_INCOMPAT_EXTENDED_SLOT_MAP 0x100
+
+
+/*
+ * Support for alternate, userspace cluster stacks.  If set, the superblock
+ * field s_cluster_info contains a tag for the alternate stack in use as
+ * well as the name of the cluster being joined.
+ * mount.ocfs2 must pass in a matching stack name.
+ *
+ * If not set, the classic stack will be used.  This is compatbile with
+ * all older versions.
+ */
+#define OCFS2_FEATURE_INCOMPAT_USERSPACE_STACK  0x0080
+
 /*
  * backup superblock flag is used to indicate that this volume
  * has backup superblocks.
@@ -267,6 +284,10 @@ struct ocfs2_new_group_input {
 #define OCFS2_VOL_UUID_LEN              16
 #define OCFS2_MAX_VOL_LABEL_LEN         64
 
+/* The alternate, userspace stack fields */
+#define OCFS2_STACK_LABEL_LEN           4
+#define OCFS2_CLUSTER_NAME_LEN          16
+
 /* Journal limits (in bytes) */
 #define OCFS2_MIN_JOURNAL_SIZE          (4 * 1024 * 1024)
 
@@ -475,6 +496,47 @@ struct ocfs2_extent_block
 };
 
 /*
+ * On disk slot map for OCFS2.  This defines the contents of the "slot_map"
+ * system file.  A slot is valid if it contains a node number >= 0.  The
+ * value -1 (0xFFFF) is OCFS2_INVALID_SLOT.  This marks a slot empty.
+ */
+struct ocfs2_slot_map {
+/*00*/  __le16 sm_slots[0];
+/*
+ * Actual on-disk size is one block.  OCFS2_MAX_SLOTS is 255,
+ * 255 * sizeof(__le16) == 512B, within the 512B block minimum blocksize.
+ */
+};
+
+struct ocfs2_extended_slot {
+/*00*/  __u8    es_valid;
+        __u8    es_reserved1[3];
+        __le32  es_node_num;
+/*10*/
+};
+
+/*
+ * The extended slot map, used when OCFS2_FEATURE_INCOMPAT_EXTENDED_SLOT_MAP
+ * is set.  It separates out the valid marker from the node number, and
+ * has room to grow.  Unlike the old slot map, this format is defined by
+ * i_size.
+ */
+struct ocfs2_slot_map_extended {
+/*00*/  struct ocfs2_extended_slot se_slots[0];
+/*
+ * Actual size is i_size of the slot_map system file.  It should
+ * match s_max_slots * sizeof(struct ocfs2_extended_slot)
+ */
+};
+
+struct ocfs2_cluster_info {
+/*00*/  __u8   ci_stack[OCFS2_STACK_LABEL_LEN];
+        __le32 ci_reserved;
+/*08*/  __u8   ci_cluster[OCFS2_CLUSTER_NAME_LEN];
+/*18*/
+};
+
+/*
  * On disk superblock for OCFS2
  * Note that it is contained inside an ocfs2_dinode, so all offsets
  * are relative to the start of ocfs2_dinode.id2.
@@ -506,7 +568,20 @@ struct ocfs2_super_block {
                                          * group header */
 /*50*/  __u8  s_label[OCFS2_MAX_VOL_LABEL_LEN]; /* Label for mounting, etc. */
 /*90*/  __u8  s_uuid[OCFS2_VOL_UUID_LEN];       /* 128-bit uuid */
-/*A0*/
+/*A0*/  struct ocfs2_cluster_info s_cluster_info; /* Selected userspace
+                                                     stack.  Only valid
+                                                     with INCOMPAT flag. */
+/*B8*/  __le64 s_reserved2[17];         /* Fill out superblock */
+/*140*/
+
+        /*
+         * NOTE: As stated above, all offsets are relative to
+         * ocfs2_dinode.id2, which is at 0xC0 in the inode.
+         * 0xC0 + 0x140 = 0x200 or 512 bytes.  A superblock must fit within
+         * our smallest blocksize, which is 512 bytes.  To ensure this,
+         * we reserve the space in s_reserved2.  Anything past s_reserved2
+         * will not be available on the smallest blocksize.
+         */
 };
 
 /*