ocfs2: Add the basic xattr disk layout in ocfs2_fs.h

[linux-2.6-omap-h63xx.git] / fs / ocfs2 / ocfs2_fs.h

diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index 4f619850ccf7fd8b80bf4888fc39849c6bb93d4b..1b46505e1e36536e5e70b2d89dd56990ec23cea0 100644 (file)
--- a/fs/ocfs2/ocfs2_fs.h
+++ b/fs/ocfs2/ocfs2_fs.h
@@ -64,6 +64,7 @@
 #define OCFS2_INODE_SIGNATURE          "INODE01"
 #define OCFS2_EXTENT_BLOCK_SIGNATURE   "EXBLK01"
 #define OCFS2_GROUP_DESC_SIGNATURE      "GROUP01"
+#define OCFS2_XATTR_BLOCK_SIGNATURE    "XATTR01"
 
 /* Compatibility flags */
 #define OCFS2_HAS_COMPAT_FEATURE(sb,mask)                      \
@@ -715,6 +716,123 @@ struct ocfs2_group_desc
 /*40*/ __u8    bg_bitmap[0];
 };
 
+/*
+ * On disk extended attribute structure for OCFS2.
+ */
+
+/*
+ * ocfs2_xattr_entry indicates one extend attribute.
+ *
+ * Note that it can be stored in inode, one block or one xattr bucket.
+ */
+struct ocfs2_xattr_entry {
+       __le32  xe_name_hash;    /* hash value of xattr prefix+suffix. */
+       __le16  xe_name_offset;  /* byte offset from the 1st etnry in the local
+                                   local xattr storage(inode, xattr block or
+                                   xattr bucket). */
+       __u8    xe_name_len;     /* xattr name len, does't include prefix. */
+       __u8    xe_type;         /* the low 7 bits indicates the name prefix's
+                                 * type and the highest 1 bits indicate whether
+                                 * the EA is stored in the local storage. */
+       __le64  xe_value_size;   /* real xattr value length. */
+};
+
+/*
+ * On disk structure for xattr header.
+ *
+ * One ocfs2_xattr_header describes how many ocfs2_xattr_entry records in
+ * the local xattr storage.
+ */
+struct ocfs2_xattr_header {
+       __le16  xh_count;                       /* contains the count of how
+                                                  many records are in the
+                                                  local xattr storage. */
+       __le16  xh_reserved1;
+       __le32  xh_reserved2;
+       __le64  xh_csum;
+       struct ocfs2_xattr_entry xh_entries[0]; /* xattr entry list. */
+};
+
+/*
+ * On disk structure for xattr value root.
+ *
+ * It is used when one extended attribute's size is larger, and we will save it
+ * in an outside cluster. It will stored in a b-tree like file content.
+ */
+struct ocfs2_xattr_value_root {
+/*00*/ __le32  xr_clusters;              /* clusters covered by xattr value. */
+       __le32  xr_reserved0;
+       __le64  xr_last_eb_blk;           /* Pointer to last extent block */
+/*10*/ struct ocfs2_extent_list xr_list; /* Extent record list */
+};
+
+/*
+ * On disk structure for xattr tree root.
+ *
+ * It is used when there are too many extended attributes for one file. These
+ * attributes will be organized and stored in an indexed-btree.
+ */
+struct ocfs2_xattr_tree_root {
+/*00*/ __le32  xt_clusters;              /* clusters covered by xattr. */
+       __le32  xt_reserved0;
+       __le64  xt_last_eb_blk;           /* Pointer to last extent block */
+/*10*/ struct ocfs2_extent_list xt_list; /* Extent record list */
+};
+
+#define OCFS2_XATTR_INDEXED 0x1
+
+/*
+ * On disk structure for xattr block.
+ */
+struct ocfs2_xattr_block {
+/*00*/ __u8    xb_signature[8];     /* Signature for verification */
+       __le16  xb_suballoc_slot;    /* Slot suballocator this
+                                       block belongs to. */
+       __le16  xb_suballoc_bit;     /* Bit offset in suballocator
+                                       block group */
+       __le32  xb_fs_generation;    /* Must match super block */
+/*10*/ __le64  xb_blkno;            /* Offset on disk, in blocks */
+       __le64  xb_csum;
+/*20*/ __le16  xb_flags;            /* Indicates whether this block contains
+                                       real xattr or a xattr tree. */
+       __le16  xb_reserved0;
+       __le32  xb_reserved1;
+       __le64  xb_reserved2;
+/*30*/ union {
+               struct ocfs2_xattr_header xb_header; /* xattr header if this
+                                                       block contains xattr */
+               struct ocfs2_xattr_tree_root xb_root;/* xattr tree root if this
+                                                       block cotains xattr
+                                                       tree. */
+       } xb_attrs;
+};
+
+#define OCFS2_XATTR_ENTRY_LOCAL                0x80
+#define OCFS2_XATTR_TYPE_MASK          0x7F
+static inline void ocfs2_xattr_set_local(struct ocfs2_xattr_entry *xe,
+                                        int local)
+{
+       if (local)
+               xe->xe_type |= OCFS2_XATTR_ENTRY_LOCAL;
+       else
+               xe->xe_type &= ~OCFS2_XATTR_ENTRY_LOCAL;
+}
+
+static inline int ocfs2_xattr_is_local(struct ocfs2_xattr_entry *xe)
+{
+       return xe->xe_type & OCFS2_XATTR_ENTRY_LOCAL;
+}
+
+static inline void ocfs2_xattr_set_type(struct ocfs2_xattr_entry *xe, int type)
+{
+       xe->xe_type |= type & OCFS2_XATTR_TYPE_MASK;
+}
+
+static inline int ocfs2_xattr_get_type(struct ocfs2_xattr_entry *xe)
+{
+       return xe->xe_type & OCFS2_XATTR_TYPE_MASK;
+}
+
 #ifdef __KERNEL__
 static inline int ocfs2_fast_symlink_chars(struct super_block *sb)
 {