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/*

   md_p.h : physical layout of Linux RAID devices

          Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 2, or (at your option)

   any later version.

   You should have received a copy of the GNU General Public License

   (for example /usr/src/linux/COPYING); if not, write to the Free

   Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#ifndef _MD_P_H

#define _MD_P_H

#include <linux/types.h>

#include <asm/byteorder.h>

/*

 * RAID superblock.

 *

 * The RAID superblock maintains some statistics on each RAID configuration.

 * Each real device in the RAID set contains it near the end of the device.

 * Some of the ideas are copied from the ext2fs implementation.

 *

 * We currently use 4096 bytes as follows:

 *

 *      word offset     function

 *

 *         0  -    31   Constant generic RAID device information.

 *        32  -    63   Generic state information.

 *        64  -   127   Personality specific information.

 *       128  -   511   12 32-words descriptors of the disks in the raid set.

 *       512  -   911   Reserved.

 *       912  -  1023   Disk specific descriptor.

 */

/*

 * If x is the real device size in bytes, we return an apparent size of:

 *

 *      y = (x & ~(MD_RESERVED_BYTES - 1)) - MD_RESERVED_BYTES

 *

 * and place the 4kB superblock at offset y.

 */

#define MD_RESERVED_BYTES               (64 * 1024)

#define MD_RESERVED_SECTORS             (MD_RESERVED_BYTES / 512)

#define MD_NEW_SIZE_SECTORS(x)          ((x & ~(MD_RESERVED_SECTORS - 1)) - MD_RESERVED_SECTORS)

#define MD_SB_BYTES                     4096

#define MD_SB_WORDS                     (MD_SB_BYTES / 4)

#define MD_SB_SECTORS                   (MD_SB_BYTES / 512)

/*

 * The following are counted in 32-bit words

 */

#define MD_SB_GENERIC_OFFSET            0

#define MD_SB_PERSONALITY_OFFSET        64

#define MD_SB_DISKS_OFFSET              128

#define MD_SB_DESCRIPTOR_OFFSET         992

#define MD_SB_GENERIC_CONSTANT_WORDS    32

#define MD_SB_GENERIC_STATE_WORDS       32

#define MD_SB_GENERIC_WORDS             (MD_SB_GENERIC_CONSTANT_WORDS + MD_SB_GENERIC_STATE_WORDS)

#define MD_SB_PERSONALITY_WORDS         64

#define MD_SB_DESCRIPTOR_WORDS          32

#define MD_SB_DISKS                     27

#define MD_SB_DISKS_WORDS               (MD_SB_DISKS*MD_SB_DESCRIPTOR_WORDS)

#define MD_SB_RESERVED_WORDS            (1024 - MD_SB_GENERIC_WORDS - MD_SB_PERSONALITY_WORDS - MD_SB_DISKS_WORDS - MD_SB_DESCRIPTOR_WORDS)

#define MD_SB_EQUAL_WORDS               (MD_SB_GENERIC_WORDS + MD_SB_PERSONALITY_WORDS + MD_SB_DISKS_WORDS)

/*

 * Device "operational" state bits

 */

#define MD_DISK_FAULTY          0 /* disk is faulty / operational */

#define MD_DISK_ACTIVE          1 /* disk is running or spare disk */

#define MD_DISK_SYNC            2 /* disk is in sync with the raid set */

#define MD_DISK_REMOVED         3 /* disk is in sync with the raid set */

#define MD_DISK_WRITEMOSTLY     9 /* disk is "write-mostly" is RAID1 config.

                                   * read requests will only be sent here in

                                   * dire need

                                   */

typedef struct mdp_device_descriptor_s {

        __u32 number;           /* 0 Device number in the entire set          */

        __u32 major;            /* 1 Device major number                      */

        __u32 minor;            /* 2 Device minor number                      */

        __u32 raid_disk;        /* 3 The role of the device in the raid set   */

        __u32 state;            /* 4 Operational state                        */

        __u32 reserved[MD_SB_DESCRIPTOR_WORDS - 5];

} mdp_disk_t;

#define MD_SB_MAGIC             0xa92b4efc

/*

 * Superblock state bits

 */

#define MD_SB_CLEAN             0

#define MD_SB_ERRORS            1

#define MD_SB_BITMAP_PRESENT    8 /* bitmap may be present nearby */

/*

 * Notes:

 * - if an array is being reshaped (restriped) in order to change the

 *   the number of active devices in the array, 'raid_disks' will be

 *   the larger of the old and new numbers.  'delta_disks' will

 *   be the "new - old".  So if +ve, raid_disks is the new value, and

 *   "raid_disks-delta_disks" is the old.  If -ve, raid_disks is the

 *   old value and "raid_disks+delta_disks" is the new (smaller) value.

 */

typedef struct mdp_superblock_s {

        /*

         * Constant generic information

         */

        __u32 md_magic;         /*  0 MD identifier                           */

        __u32 major_version;    /*  1 major version to which the set conforms */

        __u32 minor_version;    /*  2 minor version ...                       */

        __u32 patch_version;    /*  3 patchlevel version ...                  */

        __u32 gvalid_words;     /*  4 Number of used words in this section    */

        __u32 set_uuid0;        /*  5 Raid set identifier                     */

        __u32 ctime;            /*  6 Creation time                           */

        __u32 level;            /*  7 Raid personality                        */

        __u32 size;             /*  8 Apparent size of each individual disk   */

        __u32 nr_disks;         /*  9 total disks in the raid set             */

        __u32 raid_disks;       /* 10 disks in a fully functional raid set    */

        __u32 md_minor;         /* 11 preferred MD minor device number        */

        __u32 not_persistent;   /* 12 does it have a persistent superblock    */

        __u32 set_uuid1;        /* 13 Raid set identifier #2                  */

        __u32 set_uuid2;        /* 14 Raid set identifier #3                  */

        __u32 set_uuid3;        /* 15 Raid set identifier #4                  */

        __u32 gstate_creserved[MD_SB_GENERIC_CONSTANT_WORDS - 16];

        /*

         * Generic state information

         */

        __u32 utime;            /*  0 Superblock update time                  */

        __u32 state;            /*  1 State bits (clean, ...)                 */

        __u32 active_disks;     /*  2 Number of currently active disks        */

        __u32 working_disks;    /*  3 Number of working disks                 */

        __u32 failed_disks;     /*  4 Number of failed disks                  */

        __u32 spare_disks;      /*  5 Number of spare disks                   */

        __u32 sb_csum;          /*  6 checksum of the whole superblock        */

#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : defined(__BIG_ENDIAN)

        __u32 events_hi;        /*  7 high-order of superblock update count   */

        __u32 events_lo;        /*  8 low-order of superblock update count    */

        __u32 cp_events_hi;     /*  9 high-order of checkpoint update count   */

        __u32 cp_events_lo;     /* 10 low-order of checkpoint update count    */

#elif defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : defined(__LITTLE_ENDIAN)

        __u32 events_lo;        /*  7 low-order of superblock update count    */

        __u32 events_hi;        /*  8 high-order of superblock update count   */

        __u32 cp_events_lo;     /*  9 low-order of checkpoint update count    */

        __u32 cp_events_hi;     /* 10 high-order of checkpoint update count   */

#else

#error unspecified endianness

#endif

        __u32 recovery_cp;      /* 11 recovery checkpoint sector count        */

        /* There are only valid for minor_version > 90 */

        __u64 reshape_position; /* 12,13 next address in array-space for reshape */

        __u32 new_level;        /* 14 new level we are reshaping to           */

        __u32 delta_disks;      /* 15 change in number of raid_disks          */

        __u32 new_layout;       /* 16 new layout                              */

        __u32 new_chunk;        /* 17 new chunk size (bytes)                  */

        __u32 gstate_sreserved[MD_SB_GENERIC_STATE_WORDS - 18];

        /*

         * Personality information

         */

        __u32 layout;           /*  0 the array's physical layout             */

        __u32 chunk_size;       /*  1 chunk size in bytes                     */

        __u32 root_pv;          /*  2 LV root PV */

        __u32 root_block;       /*  3 LV root block */

        __u32 pstate_reserved[MD_SB_PERSONALITY_WORDS - 4];

        /*

         * Disks information

         */

        mdp_disk_t disks[MD_SB_DISKS];

        /*

         * Reserved

         */

        __u32 reserved[MD_SB_RESERVED_WORDS];

        /*

         * Active descriptor

         */

        mdp_disk_t this_disk;

} mdp_super_t;

static __inline__ __u64 md_event(mdp_super_t *sb) {

        __u64 ev = sb->events_hi;

        return (ev<<32)| sb->events_lo;

}

#define MD_SUPERBLOCK_1_TIME_SEC_MASK ((1ULL<<40) - 1)

/*

 * The version-1 superblock :

 * All numeric fields are little-endian.

 *

 * total size: 256 bytes plus 2 per device.

 *  1K allows 384 devices.

 */

struct mdp_superblock_1 {

        /* constant array information - 128 bytes */

        __le32  magic;          /* MD_SB_MAGIC: 0xa92b4efc - little endian */

        __le32  major_version;  /* 1 */

        __le32  feature_map;    /* bit 0 set if 'bitmap_offset' is meaningful */

        __le32  pad0;           /* always set to 0 when writing */

        __u8    set_uuid[16];   /* user-space generated. */

        char    set_name[32];   /* set and interpreted by user-space */

        __le64  ctime;          /* lo 40 bits are seconds, top 24 are microseconds or 0*/

        __le32  level;          /* -4 (multipath), -1 (linear), 0,1,4,5 */

        __le32  layout;         /* only for raid5 and raid10 currently */

        __le64  size;           /* used size of component devices, in 512byte sectors */

        __le32  chunksize;      /* in 512byte sectors */

        __le32  raid_disks;

        __le32  bitmap_offset;  /* sectors after start of superblock that bitmap starts

                                 * NOTE: signed, so bitmap can be before superblock

                                 * only meaningful of feature_map[0] is set.

                                 */

        /* These are only valid with feature bit '4' */

        __le32  new_level;      /* new level we are reshaping to                */

        __le64  reshape_position;       /* next address in array-space for reshape */

        __le32  delta_disks;    /* change in number of raid_disks               */

        __le32  new_layout;     /* new layout                                   */

        __le32  new_chunk;      /* new chunk size (512byte sectors)             */

        __le32  new_offset;     /* signed number to add to data_offset in new

                                 * layout.  0 == no-change.  This can be

                                 * different on each device in the array.

                                 */

        /* constant this-device information - 64 bytes */

        __le64  data_offset;    /* sector start of data, often 0 */

        __le64  data_size;      /* sectors in this device that can be used for data */

        __le64  super_offset;   /* sector start of this superblock */

        __le64  recovery_offset;/* sectors before this offset (from data_offset) have been recovered */

        __le32  dev_number;     /* permanent identifier of this  device - not role in raid */

        __le32  cnt_corrected_read; /* number of read errors that were corrected by re-writing */

        __u8    device_uuid[16]; /* user-space setable, ignored by kernel */

        __u8    devflags;       /* per-device flags.  Only one defined...*/

#define WriteMostly1    1       /* mask for writemostly flag in above */

        /* Bad block log.  If there are any bad blocks the feature flag is set.

         * If offset and size are non-zero, that space is reserved and available

         */

        __u8    bblog_shift;    /* shift from sectors to block size */

        __le16  bblog_size;     /* number of sectors reserved for list */

        __le32  bblog_offset;   /* sector offset from superblock to bblog,

                                 * signed - not unsigned */

        /* array state information - 64 bytes */

        __le64  utime;          /* 40 bits second, 24 bits microseconds */

        __le64  events;         /* incremented when superblock updated */

        __le64  resync_offset;  /* data before this offset (from data_offset) known to be in sync */

        __le32  sb_csum;        /* checksum up to devs[max_dev] */

        __le32  max_dev;        /* size of devs[] array to consider */

        __u8    pad3[64-32];    /* set to 0 when writing */

        /* device state information. Indexed by dev_number.

         * 2 bytes per device

         * Note there are no per-device state flags. State information is rolled

         * into the 'roles' value.  If a device is spare or faulty, then it doesn't

         * have a meaningful role.

         */

        __le16  dev_roles[0];    /* role in array, or 0xffff for a spare, or 0xfffe for faulty */

};

/* feature_map bits */

#define MD_FEATURE_BITMAP_OFFSET        1

#define MD_FEATURE_RECOVERY_OFFSET      2 /* recovery_offset is present and

                                           * must be honoured

                                           */

#define MD_FEATURE_RESHAPE_ACTIVE       4

#define MD_FEATURE_BAD_BLOCKS           8 /* badblock list is not empty */

#define MD_FEATURE_REPLACEMENT          16 /* This device is replacing an

                                            * active device with same 'role'.

                                            * 'recovery_offset' is also set.

                                            */

#define MD_FEATURE_RESHAPE_BACKWARDS    32 /* Reshape doesn't change number

                                            * of devices, but is going

                                            * backwards anyway.

                                            */

#define MD_FEATURE_NEW_OFFSET           64 /* new_offset must be honoured */

#define MD_FEATURE_RECOVERY_BITMAP      128 /* recovery that is happening

                                             * is guided by bitmap.

                                             */

#define MD_FEATURE_ALL                  (MD_FEATURE_BITMAP_OFFSET       \

                                        |MD_FEATURE_RECOVERY_OFFSET     \

                                        |MD_FEATURE_RESHAPE_ACTIVE      \

                                        |MD_FEATURE_BAD_BLOCKS          \

                                        |MD_FEATURE_REPLACEMENT         \

                                        |MD_FEATURE_RESHAPE_BACKWARDS   \

                                        |MD_FEATURE_NEW_OFFSET          \

                                        |MD_FEATURE_RECOVERY_BITMAP     \

                                        )

#endif