1 files changed, 85 insertions, 3 deletions

diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index 7ab6e9e5e77c..e4288b446ec0 100644
--- a/fs/ocfs2/ocfs2_fs.h
+++ b/fs/ocfs2/ocfs2_fs.h
@@ -68,6 +68,7 @@
 #define OCFS2_DIR_TRAILER_SIGNATURE     "DIRTRL1"
 #define OCFS2_DX_ROOT_SIGNATURE         "DXDIR01"
 #define OCFS2_DX_LEAF_SIGNATURE         "DXLEAF1"
+#define OCFS2_REFCOUNT_BLOCK_SIGNATURE  "REFCNT1"
 
 /* Compatibility flags */
 #define OCFS2_HAS_COMPAT_FEATURE(sb,mask)                       \
@@ -160,6 +161,9 @@
 /* Metadata checksum and error correction */
 #define OCFS2_FEATURE_INCOMPAT_META_ECC         0x0800
 
+/* Refcount tree support */
+#define OCFS2_FEATURE_INCOMPAT_REFCOUNT_TREE    0x1000
+
 /*
  * backup superblock flag is used to indicate that this volume
  * has backup superblocks.
@@ -223,6 +227,7 @@
 #define OCFS2_HAS_XATTR_FL      (0x0002)
 #define OCFS2_INLINE_XATTR_FL   (0x0004)
 #define OCFS2_INDEXED_DIR_FL    (0x0008)
+#define OCFS2_HAS_REFCOUNT_FL   (0x0010)
 
 /* Inode attributes, keep in sync with EXT2 */
 #define OCFS2_SECRM_FL          (0x00000001)    /* Secure deletion */
@@ -241,8 +246,11 @@
 /*
  * Extent record flags (e_node.leaf.flags)
  */
-#define OCFS2_EXT_UNWRITTEN     (0x01)  /* Extent is allocated but
-                                         * unwritten */
+#define OCFS2_EXT_UNWRITTEN             (0x01)  /* Extent is allocated but
+                                                 * unwritten */
+#define OCFS2_EXT_REFCOUNTED            (0x02)  /* Extent is reference
+                                                 * counted in an associated
+                                                 * refcount tree */
 
 /*
  * ioctl commands
@@ -717,7 +725,8 @@ struct ocfs2_dinode {
         __le64 i_xattr_loc;
 /*80*/  struct ocfs2_block_check i_check;       /* Error checking */
 /*88*/  __le64 i_dx_root;               /* Pointer to dir index root block */
-        __le64 i_reserved2[5];
+/*90*/  __le64 i_refcount_loc;
+        __le64 i_reserved2[4];
 /*B8*/  union {
                 __le64 i_pad1;          /* Generic way to refer to this
                                            64bit union */
@@ -901,6 +910,59 @@ struct ocfs2_group_desc
 /*40*/  __u8    bg_bitmap[0];
 };
 
+struct ocfs2_refcount_rec {
+/*00*/  __le64 r_cpos;          /* Physical offset, in clusters */
+        __le32 r_clusters;      /* Clusters covered by this extent */
+        __le32 r_refcount;      /* Reference count of this extent */
+/*10*/
+};
+
+#define OCFS2_REFCOUNT_LEAF_FL          (0x00000001)
+#define OCFS2_REFCOUNT_TREE_FL          (0x00000002)
+
+struct ocfs2_refcount_list {
+/*00*/  __le16 rl_count;        /* Maximum number of entries possible
+                                   in rl_records */
+        __le16 rl_used;         /* Current number of used records */
+        __le32 rl_reserved2;
+        __le64 rl_reserved1;    /* Pad to sizeof(ocfs2_refcount_record) */
+/*10*/  struct ocfs2_refcount_rec rl_recs[0];   /* Refcount records */
+};
+
+
+struct ocfs2_refcount_block {
+/*00*/  __u8 rf_signature[8];           /* Signature for verification */
+        __le16 rf_suballoc_slot;        /* Slot suballocator this block
+                                           belongs to */
+        __le16 rf_suballoc_bit;         /* Bit offset in suballocator
+                                           block group */
+        __le32 rf_fs_generation;        /* Must match superblock */
+/*10*/  __le64 rf_blkno;                /* Offset on disk, in blocks */
+        __le64 rf_parent;               /* Parent block, only valid if
+                                           OCFS2_REFCOUNT_LEAF_FL is set in
+                                           rf_flags */
+/*20*/  struct ocfs2_block_check rf_check;      /* Error checking */
+        __le64 rf_last_eb_blk;          /* Pointer to last extent block */
+/*30*/  __le32 rf_count;                /* Number of inodes sharing this
+                                           refcount tree */
+        __le32 rf_flags;                /* See the flags above */
+        __le32 rf_clusters;             /* clusters covered by refcount tree. */
+        __le32 rf_cpos;                 /* cluster offset in refcount tree.*/
+/*40*/  __le32 rf_generation;           /* generation number. all be the same
+                                         * for the same refcount tree. */
+        __le32 rf_reserved0;
+        __le64 rf_reserved1[7];
+/*80*/  union {
+                struct ocfs2_refcount_list rf_records;  /* List of refcount
+                                                          records */
+                struct ocfs2_extent_list rf_list;       /* Extent record list,
+                                                        only valid if
+                                                        OCFS2_REFCOUNT_TREE_FL
+                                                        is set in rf_flags */
+        };
+/* Actual on-disk size is one block */
+};
+
 /*
  * On disk extended attribute structure for OCFS2.
  */
@@ -1312,6 +1374,26 @@ static inline u16 ocfs2_xattr_recs_per_xb(struct super_block *sb)
 
         return size / sizeof(struct ocfs2_extent_rec);
 }
+
+static inline u16 ocfs2_extent_recs_per_rb(struct super_block *sb)
+{
+        int size;
+
+        size = sb->s_blocksize -
+                offsetof(struct ocfs2_refcount_block, rf_list.l_recs);
+
+        return size / sizeof(struct ocfs2_extent_rec);
+}
+
+static inline u16 ocfs2_refcount_recs_per_rb(struct super_block *sb)
+{
+        int size;
+
+        size = sb->s_blocksize -
+                offsetof(struct ocfs2_refcount_block, rf_records.rl_recs);
+
+        return size / sizeof(struct ocfs2_refcount_rec);
+}
 #else
 static inline int ocfs2_fast_symlink_chars(int blocksize)
 {