exofs: Multi-device mirror support

[safe/jmp/linux-2.6] / fs / exofs / common.h

diff --git a/fs/exofs/common.h b/fs/exofs/common.h
index ce1c716..b1b178e 100644 (file)
--- a/fs/exofs/common.h
+++ b/fs/exofs/common.h
@@ -49,6 +49,7 @@
 #define EXOFS_MIN_PID   0x10000        /* Smallest partition ID */
 #define EXOFS_OBJ_OFF  0x10000 /* offset for objects */
 #define EXOFS_SUPER_ID 0x10000 /* object ID for on-disk superblock */
+#define EXOFS_DEVTABLE_ID 0x10001 /* object ID for on-disk device table */
 #define EXOFS_ROOT_ID  0x10002 /* object ID for root directory */
 
 /* exofs Application specific page/attribute */
@@ -78,17 +79,67 @@ enum {
 #define EXOFS_SUPER_MAGIC      0x5DF5
 
 /*
- * The file system control block - stored in an object's data (mainly, the one
- * with ID EXOFS_SUPER_ID).  This is where the in-memory superblock is stored
- * on disk.  Right now it just has a magic value, which is basically a sanity
- * check on our ability to communicate with the object store.
+ * The file system control block - stored in object EXOFS_SUPER_ID's data.
+ * This is where the in-memory superblock is stored on disk.
  */
+enum {EXOFS_FSCB_VER = 1, EXOFS_DT_VER = 1};
 struct exofs_fscb {
        __le64  s_nextid;       /* Highest object ID used */
-       __le32  s_numfiles;     /* Number of files on fs */
+       __le64  s_numfiles;     /* Number of files on fs */
+       __le32  s_version;      /* == EXOFS_FSCB_VER */
        __le16  s_magic;        /* Magic signature */
        __le16  s_newfs;        /* Non-zero if this is a new fs */
-};
+
+       /* From here on it's a static part, only written by mkexofs */
+       __le64  s_dev_table_oid;   /* Resurved, not used */
+       __le64  s_dev_table_count; /* == 0 means no dev_table */
+} __packed;
+
+/*
+ * Describes the raid used in the FS. It is part of the device table.
+ * This here is taken from the pNFS-objects definition. In exofs we
+ * use one raid policy through-out the filesystem. (NOTE: the funny
+ * alignment at begining. We take care of it at exofs_device_table.
+ */
+struct exofs_dt_data_map {
+       __le32  cb_num_comps;
+       __le64  cb_stripe_unit;
+       __le32  cb_group_width;
+       __le32  cb_group_depth;
+       __le32  cb_mirror_cnt;
+       __le32  cb_raid_algorithm;
+} __packed;
+
+/*
+ * This is an osd device information descriptor. It is a single entry in
+ * the exofs device table. It describes an osd target lun which
+ * contains data belonging to this FS. (Same partition_id on all devices)
+ */
+struct exofs_dt_device_info {
+       __le32  systemid_len;
+       u8      systemid[OSD_SYSTEMID_LEN];
+       __le64  long_name_offset;       /* If !0 then offset-in-file */
+       __le32  osdname_len;            /* */
+       u8      osdname[44];            /* Embbeded, Ususally an asci uuid */
+} __packed;
+
+/*
+ * The EXOFS device table - stored in object EXOFS_DEVTABLE_ID's data.
+ * It contains the raid used for this multy-device FS and an array of
+ * participating devices.
+ */
+struct exofs_device_table {
+       __le32                          dt_version;     /* == EXOFS_DT_VER */
+       struct exofs_dt_data_map        dt_data_map;    /* Raid policy to use */
+
+       /* Resurved space For future use. Total includeing this:
+        * (8 * sizeof(le64))
+        */
+       __le64                          __Resurved[4];
+
+       __le64                          dt_num_devices; /* Array size */
+       struct exofs_dt_device_info     dt_dev_table[]; /* Array of devices */
+} __packed;
 
 /****************************************************************************
  * inode-related things