FreeBSD/Linux Kernel Cross Reference
sys/vfs/hammer/hammer_disk.h

     /*
      * Copyright (c) 2007 The DragonFly Project.  All rights reserved.
      * 
      * This code is derived from software contributed to The DragonFly Project
      * by Matthew Dillon <dillon@backplane.com>
      * 
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
     * 
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in
     *    the documentation and/or other materials provided with the
     *    distribution.
     * 3. Neither the name of The DragonFly Project nor the names of its
     *    contributors may be used to endorse or promote products derived
     *    from this software without specific, prior written permission.
     * 
     * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
     * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
     * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     * 
     * $DragonFly: src/sys/vfs/hammer/hammer_disk.h,v 1.55 2008/11/13 02:18:43 dillon Exp $
     */
    
    #ifndef VFS_HAMMER_DISK_H_
    #define VFS_HAMMER_DISK_H_
    
    #ifndef _SYS_UUID_H_
    #include <sys/uuid.h>
    #endif
    
    /*
     * The structures below represent the on-disk format for a HAMMER
     * filesystem.  Note that all fields for on-disk structures are naturally
     * aligned.  The host endian format is used - compatibility is possible
     * if the implementation detects reversed endian and adjusts data accordingly.
     *
     * Most of HAMMER revolves around the concept of an object identifier.  An
     * obj_id is a 64 bit quantity which uniquely identifies a filesystem object
     * FOR THE ENTIRE LIFE OF THE FILESYSTEM.  This uniqueness allows backups
     * and mirrors to retain varying amounts of filesystem history by removing
     * any possibility of conflict through identifier reuse.
     *
     * A HAMMER filesystem may span multiple volumes.
     *
     * A HAMMER filesystem uses a 16K filesystem buffer size.  All filesystem
     * I/O is done in multiples of 16K.  Most buffer-sized headers such as those
     * used by volumes, super-clusters, clusters, and basic filesystem buffers
     * use fixed-sized A-lists which are heavily dependant on HAMMER_BUFSIZE.
     *
     * 64K X-bufs are used for blocks >= a file's 1MB mark.
     *
     * Per-volume storage limit: 52 bits            4096 TB
     * Per-Zone storage limit: 59 bits              512 KTB (due to blockmap)
     * Per-filesystem storage limit: 60 bits        1 MTB
     */
    #define HAMMER_BUFSIZE          16384
    #define HAMMER_XBUFSIZE         65536
    #define HAMMER_XDEMARC          (1024 * 1024)
    #define HAMMER_BUFMASK          (HAMMER_BUFSIZE - 1)
    #define HAMMER_XBUFMASK         (HAMMER_XBUFSIZE - 1)
    #define HAMMER_BUFFER_BITS      14
    
    #if (1 << HAMMER_BUFFER_BITS) != HAMMER_BUFSIZE
    #error "HAMMER_BUFFER_BITS BROKEN"
    #endif
    
    #define HAMMER_BUFSIZE64        ((u_int64_t)HAMMER_BUFSIZE)
    #define HAMMER_BUFMASK64        ((u_int64_t)HAMMER_BUFMASK)
    
    #define HAMMER_XBUFSIZE64       ((u_int64_t)HAMMER_XBUFSIZE)
    #define HAMMER_XBUFMASK64       ((u_int64_t)HAMMER_XBUFMASK)
    
    #define HAMMER_OFF_ZONE_MASK    0xF000000000000000ULL /* zone portion */
    #define HAMMER_OFF_VOL_MASK     0x0FF0000000000000ULL /* volume portion */
    #define HAMMER_OFF_SHORT_MASK   0x000FFFFFFFFFFFFFULL /* offset portion */
    #define HAMMER_OFF_LONG_MASK    0x0FFFFFFFFFFFFFFFULL /* offset portion */
    #define HAMMER_OFF_SHORT_REC_MASK 0x000FFFFFFF000000ULL /* recovery boundary */
    #define HAMMER_OFF_LONG_REC_MASK 0x0FFFFFFFFF000000ULL /* recovery boundary */
    #define HAMMER_RECOVERY_BND     0x0000000001000000ULL
    
    #define HAMMER_OFF_BAD          ((hammer_off_t)-1)
    
    /*
     * The current limit of volumes that can make up a HAMMER FS
     */
    #define HAMMER_MAX_VOLUMES      256
   
   /*
    * Hammer transction ids are 64 bit unsigned integers and are usually
    * synchronized with the time of day in nanoseconds.
    *
    * Hammer offsets are used for FIFO indexing and embed a cycle counter
    * and volume number in addition to the offset.  Most offsets are required
    * to be 64-byte aligned.
    */
   typedef u_int64_t hammer_tid_t;
   typedef u_int64_t hammer_off_t;
   typedef u_int32_t hammer_seq_t;
   typedef u_int32_t hammer_crc_t;
   
   #define HAMMER_MIN_TID          0ULL                    /* unsigned */
   #define HAMMER_MAX_TID          0xFFFFFFFFFFFFFFFFULL   /* unsigned */
   #define HAMMER_MIN_KEY          -0x8000000000000000LL   /* signed */
   #define HAMMER_MAX_KEY          0x7FFFFFFFFFFFFFFFLL    /* signed */
   #define HAMMER_MIN_OBJID        HAMMER_MIN_KEY          /* signed */
   #define HAMMER_MAX_OBJID        HAMMER_MAX_KEY          /* signed */
   #define HAMMER_MIN_RECTYPE      0x0U                    /* unsigned */
   #define HAMMER_MAX_RECTYPE      0xFFFFU                 /* unsigned */
   #define HAMMER_MIN_OFFSET       0ULL                    /* unsigned */
   #define HAMMER_MAX_OFFSET       0xFFFFFFFFFFFFFFFFULL   /* unsigned */
   
   /*
    * hammer_off_t has several different encodings.  Note that not all zones
    * encode a vol_no.
    *
    * zone 0:              reserved for sanity
    * zone 1 (z,v,o):      raw volume relative (offset 0 is the volume header)
    * zone 2 (z,v,o):      raw buffer relative (offset 0 is the first buffer)
    * zone 3 (z,o):        undo fifo       - actually fixed phys array in vol hdr
    * zone 4 (z,v,o):      freemap         - only real blockmap
    * zone 8 (z,v,o):      B-Tree          - actually zone-2 address
    * zone 9 (z,v,o):      Record          - actually zone-2 address
    * zone 10 (z,v,o):     Large-data      - actually zone-2 address
    * zone 15:             reserved for sanity
    *
    * layer1/layer2 direct map:
    *      zzzzvvvvvvvvoooo oooooooooooooooo oooooooooooooooo oooooooooooooooo
    *      ----111111111111 1111112222222222 222222222ooooooo oooooooooooooooo
    */
   
   #define HAMMER_ZONE_RAW_VOLUME          0x1000000000000000ULL
   #define HAMMER_ZONE_RAW_BUFFER          0x2000000000000000ULL
   #define HAMMER_ZONE_UNDO                0x3000000000000000ULL
   #define HAMMER_ZONE_FREEMAP             0x4000000000000000ULL
   #define HAMMER_ZONE_RESERVED05          0x5000000000000000ULL
   #define HAMMER_ZONE_RESERVED06          0x6000000000000000ULL
   #define HAMMER_ZONE_RESERVED07          0x7000000000000000ULL
   #define HAMMER_ZONE_BTREE               0x8000000000000000ULL
   #define HAMMER_ZONE_META                0x9000000000000000ULL
   #define HAMMER_ZONE_LARGE_DATA          0xA000000000000000ULL
   #define HAMMER_ZONE_SMALL_DATA          0xB000000000000000ULL
   #define HAMMER_ZONE_RESERVED0C          0xC000000000000000ULL
   #define HAMMER_ZONE_RESERVED0D          0xD000000000000000ULL
   #define HAMMER_ZONE_RESERVED0E          0xE000000000000000ULL
   #define HAMMER_ZONE_UNAVAIL             0xF000000000000000ULL
   
   #define HAMMER_ZONE_RAW_VOLUME_INDEX    1
   #define HAMMER_ZONE_RAW_BUFFER_INDEX    2
   #define HAMMER_ZONE_UNDO_INDEX          3
   #define HAMMER_ZONE_FREEMAP_INDEX       4
   #define HAMMER_ZONE_BTREE_INDEX         8
   #define HAMMER_ZONE_META_INDEX          9
   #define HAMMER_ZONE_LARGE_DATA_INDEX    10
   #define HAMMER_ZONE_SMALL_DATA_INDEX    11
   #define HAMMER_ZONE_UNAVAIL_INDEX       15      /* unavailable */
   
   #define HAMMER_MAX_ZONES                16
   
   #define HAMMER_VOL_ENCODE(vol_no)                       \
           ((hammer_off_t)((vol_no) & 255) << 52)
   #define HAMMER_VOL_DECODE(ham_off)                      \
           (int32_t)(((hammer_off_t)(ham_off) >> 52) & 255)
   #define HAMMER_ZONE_DECODE(ham_off)                     \
           (int32_t)(((hammer_off_t)(ham_off) >> 60))
   #define HAMMER_ZONE_ENCODE(zone, ham_off)               \
           (((hammer_off_t)(zone) << 60) | (ham_off))
   #define HAMMER_SHORT_OFF_ENCODE(offset)                 \
           ((hammer_off_t)(offset) & HAMMER_OFF_SHORT_MASK)
   #define HAMMER_LONG_OFF_ENCODE(offset)                  \
           ((hammer_off_t)(offset) & HAMMER_OFF_LONG_MASK)
   
   #define HAMMER_ENCODE_RAW_VOLUME(vol_no, offset)        \
           (HAMMER_ZONE_RAW_VOLUME |                       \
           HAMMER_VOL_ENCODE(vol_no) |                     \
           HAMMER_SHORT_OFF_ENCODE(offset))
   
   #define HAMMER_ENCODE_RAW_BUFFER(vol_no, offset)        \
           (HAMMER_ZONE_RAW_BUFFER |                       \
           HAMMER_VOL_ENCODE(vol_no) |                     \
           HAMMER_SHORT_OFF_ENCODE(offset))
   
   #define HAMMER_ENCODE_FREEMAP(vol_no, offset)           \
           (HAMMER_ZONE_FREEMAP |                          \
           HAMMER_VOL_ENCODE(vol_no) |                     \
           HAMMER_SHORT_OFF_ENCODE(offset))
   
   /*
    * Large-Block backing store
    *
    * A blockmap is a two-level map which translates a blockmap-backed zone
    * offset into a raw zone 2 offset.  Each layer handles 18 bits.  The 8M
    * large-block size is 23 bits so two layers gives us 23+18+18 = 59 bits
    * of address space.
    *
    * When using hinting for a blockmap lookup, the hint is lost when the
    * scan leaves the HINTBLOCK, which is typically several LARGEBLOCK's.
    * HINTBLOCK is a heuristic.
    */
   #define HAMMER_HINTBLOCK_SIZE           (HAMMER_LARGEBLOCK_SIZE * 4)
   #define HAMMER_HINTBLOCK_MASK64         ((u_int64_t)HAMMER_HINTBLOCK_SIZE - 1)
   #define HAMMER_LARGEBLOCK_SIZE          (8192 * 1024)
   #define HAMMER_LARGEBLOCK_OVERFILL      (6144 * 1024)
   #define HAMMER_LARGEBLOCK_SIZE64        ((u_int64_t)HAMMER_LARGEBLOCK_SIZE)
   #define HAMMER_LARGEBLOCK_MASK          (HAMMER_LARGEBLOCK_SIZE - 1)
   #define HAMMER_LARGEBLOCK_MASK64        ((u_int64_t)HAMMER_LARGEBLOCK_SIZE - 1)
   #define HAMMER_LARGEBLOCK_BITS          23
   #if (1 << HAMMER_LARGEBLOCK_BITS) != HAMMER_LARGEBLOCK_SIZE
   #error "HAMMER_LARGEBLOCK_BITS BROKEN"
   #endif
   
   #define HAMMER_BUFFERS_PER_LARGEBLOCK                   \
           (HAMMER_LARGEBLOCK_SIZE / HAMMER_BUFSIZE)
   #define HAMMER_BUFFERS_PER_LARGEBLOCK_MASK              \
           (HAMMER_BUFFERS_PER_LARGEBLOCK - 1)
   #define HAMMER_BUFFERS_PER_LARGEBLOCK_MASK64            \
           ((hammer_off_t)HAMMER_BUFFERS_PER_LARGEBLOCK_MASK)
   
   /*
    * Maximum number of mirrors operating in master mode (multi-master
    * clustering and mirroring).
    */
   #define HAMMER_MAX_MASTERS              16
   
   /*
    * The blockmap is somewhat of a degenerate structure.  HAMMER only actually
    * uses it in its original incarnation to implement the free-map.
    *
    * zone:1       raw volume (no blockmap)
    * zone:2       raw buffer (no blockmap)
    * zone:3       undo-map   (direct layer2 array in volume header)
    * zone:4       free-map   (the only real blockmap)
    * zone:8-15    zone id used to classify big-block only, address is actually
    *              a zone-2 address.
    */
   struct hammer_blockmap {
           hammer_off_t    phys_offset;    /* zone-2 physical offset */
           hammer_off_t    first_offset;   /* zone-X logical offset (zone 3) */
           hammer_off_t    next_offset;    /* zone-X logical offset */
           hammer_off_t    alloc_offset;   /* zone-X logical offset */
           u_int32_t       reserved01;
           hammer_crc_t    entry_crc;
   };
   
   typedef struct hammer_blockmap *hammer_blockmap_t;
   
   #define HAMMER_BLOCKMAP_CRCSIZE \
           offsetof(struct hammer_blockmap, entry_crc)
   
   /*
    * The blockmap is a 2-layer entity made up of big-blocks.  The first layer
    * contains 262144 32-byte entries (18 bits), the second layer contains
    * 524288 16-byte entries (19 bits), representing 8MB (23 bit) blockmaps.
    * 18+19+23 = 60 bits.  The top four bits are the zone id.
    *
    * Currently only the freemap utilizes both layers in all their glory.
    * All primary data/meta-data zones actually encode a zone-2 address
    * requiring no real blockmap translation.
    *
    * The freemap uses the upper 8 bits of layer-1 to identify the volume,
    * thus any space allocated via the freemap can be directly translated
    * to a zone:2 (or zone:8-15) address.
    *
    * zone-X blockmap offset: [z:4][layer1:18][layer2:19][bigblock:23]
    */
   struct hammer_blockmap_layer1 {
           hammer_off_t    blocks_free;    /* big-blocks free */
           hammer_off_t    phys_offset;    /* UNAVAIL or zone-2 */
           hammer_off_t    reserved01;
           hammer_crc_t    layer2_crc;     /* xor'd crc's of HAMMER_BLOCKSIZE */
                                           /* (not yet used) */
           hammer_crc_t    layer1_crc;     /* MUST BE LAST FIELD OF STRUCTURE*/
   };
   
   typedef struct hammer_blockmap_layer1 *hammer_blockmap_layer1_t;
   
   #define HAMMER_LAYER1_CRCSIZE   \
           offsetof(struct hammer_blockmap_layer1, layer1_crc)
   
   /*
    * layer2 entry for 8MB bigblock.
    *
    * NOTE: bytes_free is signed and can legally go negative if/when data
    *       de-dup occurs.  This field will never go higher than
    *       HAMMER_LARGEBLOCK_SIZE.  If exactly HAMMER_LARGEBLOCK_SIZE
    *       the big-block is completely free.
    */
   struct hammer_blockmap_layer2 {
           u_int8_t        zone;           /* typed allocation zone */
           u_int8_t        unused01;
           u_int16_t       unused02;
           u_int32_t       append_off;     /* allocatable space index */
           int32_t         bytes_free;     /* bytes free within this bigblock */
           hammer_crc_t    entry_crc;
   };
   
   typedef struct hammer_blockmap_layer2 *hammer_blockmap_layer2_t;
   
   #define HAMMER_LAYER2_CRCSIZE   \
           offsetof(struct hammer_blockmap_layer2, entry_crc)
   
   #define HAMMER_BLOCKMAP_FREE    0ULL
   #define HAMMER_BLOCKMAP_UNAVAIL ((hammer_off_t)-1LL)
   
   #define HAMMER_BLOCKMAP_RADIX1  /* 262144 (18) */       \
           (HAMMER_LARGEBLOCK_SIZE / sizeof(struct hammer_blockmap_layer1))
   #define HAMMER_BLOCKMAP_RADIX2  /* 524288 (19) */       \
           (HAMMER_LARGEBLOCK_SIZE / sizeof(struct hammer_blockmap_layer2))
   
   #define HAMMER_BLOCKMAP_RADIX1_PERBUFFER        \
           (HAMMER_BLOCKMAP_RADIX1 / (HAMMER_LARGEBLOCK_SIZE / HAMMER_BUFSIZE))
   #define HAMMER_BLOCKMAP_RADIX2_PERBUFFER        \
           (HAMMER_BLOCKMAP_RADIX2 / (HAMMER_LARGEBLOCK_SIZE / HAMMER_BUFSIZE))
   
   #define HAMMER_BLOCKMAP_LAYER1  /* 18+19+23 */          \
           (HAMMER_BLOCKMAP_RADIX1 * HAMMER_BLOCKMAP_LAYER2)
   #define HAMMER_BLOCKMAP_LAYER2  /* 19+23 - 4TB */               \
           (HAMMER_BLOCKMAP_RADIX2 * HAMMER_LARGEBLOCK_SIZE64)
   
   #define HAMMER_BLOCKMAP_LAYER1_MASK     (HAMMER_BLOCKMAP_LAYER1 - 1)
   #define HAMMER_BLOCKMAP_LAYER2_MASK     (HAMMER_BLOCKMAP_LAYER2 - 1)
   
   /*
    * byte offset within layer1 or layer2 big-block for the entry representing
    * a zone-2 physical offset. 
    */
   #define HAMMER_BLOCKMAP_LAYER1_OFFSET(zone2_offset)     \
           (((zone2_offset) & HAMMER_BLOCKMAP_LAYER1_MASK) /       \
            HAMMER_BLOCKMAP_LAYER2 * sizeof(struct hammer_blockmap_layer1))
   
   #define HAMMER_BLOCKMAP_LAYER2_OFFSET(zone2_offset)     \
           (((zone2_offset) & HAMMER_BLOCKMAP_LAYER2_MASK) /       \
           HAMMER_LARGEBLOCK_SIZE64 * sizeof(struct hammer_blockmap_layer2))
   
   /*
    * HAMMER UNDO parameters.  The UNDO fifo is mapped directly in the volume
    * header with an array of layer2 structures.  A maximum of (128x8MB) = 1GB
    * may be reserved.  The size of the undo fifo is usually set a newfs time
    * but can be adjusted if the filesystem is taken offline.
    */
   #define HAMMER_UNDO_LAYER2      128     /* max layer2 undo mapping entries */
   
   /*
    * All on-disk HAMMER structures which make up elements of the UNDO FIFO
    * contain a hammer_fifo_head and hammer_fifo_tail structure.  This structure
    * contains all the information required to validate the fifo element
    * and to scan the fifo in either direction.  The head is typically embedded
    * in higher level hammer on-disk structures while the tail is typically
    * out-of-band.  hdr_size is the size of the whole mess, including the tail.
    *
    * All undo structures are guaranteed to not cross a 16K filesystem
    * buffer boundary.  Most undo structures are fairly small.  Data spaces
    * are not immediately reused by HAMMER so file data is not usually recorded
    * as part of an UNDO.
    *
    * PAD elements are allowed to take up only 8 bytes of space as a special
    * case, containing only hdr_signature, hdr_type, and hdr_size fields,
    * and with the tail overloaded onto the head structure for 8 bytes total.
    *
    * Every undo record has a sequence number.  This number is unrelated to
    * transaction ids and instead collects the undo transactions associated
    * with a single atomic operation.  A larger transactional operation, such
    * as a remove(), may consist of several smaller atomic operations
    * representing raw meta-data operations.
    *
    *                              HAMMER VERSION 4 CHANGES
    *
    * In HAMMER version 4 the undo structure alignment is reduced from 16384
    * to 512 bytes in order to ensure that each 512 byte sector begins with
    * a header.  The reserved01 field in the header is now a 32 bit sequence
    * number.  This allows the recovery code to detect missing sectors
    * without relying on the 32-bit crc and to definitively identify the current
    * undo sequence space without having to rely on information from the volume
    * header.  In addition, new REDO entries in the undo space are used to
    * record write, write/extend, and transaction id updates.
    *
    * The grand result is:
    *
    * (1) The volume header no longer needs to be synchronized for most
    *     flush and fsync operations.
    *
    * (2) Most fsync operations need only lay down REDO records
    *
    * (3) Data overwrite for nohistory operations covered by REDO records
    *     can be supported (instead of rolling a new block allocation),
    *     by rolling UNDO for the prior contents of the data.
    *
    *                              HAMMER VERSION 5 CHANGES
    *
    * Hammer version 5 contains a minor adjustment making layer2's bytes_free
    * field signed, allowing dedup to push it into the negative domain.
    */
   #define HAMMER_HEAD_ONDISK_SIZE         32
   #define HAMMER_HEAD_ALIGN               8
   #define HAMMER_HEAD_ALIGN_MASK          (HAMMER_HEAD_ALIGN - 1)
   #define HAMMER_TAIL_ONDISK_SIZE         8
   #define HAMMER_HEAD_DOALIGN(bytes)      \
           (((bytes) + HAMMER_HEAD_ALIGN_MASK) & ~HAMMER_HEAD_ALIGN_MASK)
   
   #define HAMMER_UNDO_ALIGN               512
   #define HAMMER_UNDO_ALIGN64             ((u_int64_t)512)
   #define HAMMER_UNDO_MASK                (HAMMER_UNDO_ALIGN - 1)
   #define HAMMER_UNDO_MASK64              (HAMMER_UNDO_ALIGN64 - 1)
   
   struct hammer_fifo_head {
           u_int16_t hdr_signature;
           u_int16_t hdr_type;
           u_int32_t hdr_size;     /* Aligned size of the whole mess */
           u_int32_t hdr_seq;      /* Sequence number */
           hammer_crc_t hdr_crc;   /* XOR crc up to field w/ crc after field */
   };
   
   #define HAMMER_FIFO_HEAD_CRCOFF offsetof(struct hammer_fifo_head, hdr_crc)
   
   struct hammer_fifo_tail {
           u_int16_t tail_signature;
           u_int16_t tail_type;
           u_int32_t tail_size;    /* aligned size of the whole mess */
   };
   
   typedef struct hammer_fifo_head *hammer_fifo_head_t;
   typedef struct hammer_fifo_tail *hammer_fifo_tail_t;
   
   /*
    * Fifo header types.
    */
   #define HAMMER_HEAD_TYPE_PAD    (0x0040U|HAMMER_HEAD_FLAG_FREE)
   #define HAMMER_HEAD_TYPE_DUMMY  0x0041U         /* dummy entry w/seqno */
   #define HAMMER_HEAD_TYPE_42     0x0042U
   #define HAMMER_HEAD_TYPE_UNDO   0x0043U         /* random UNDO information */
   #define HAMMER_HEAD_TYPE_REDO   0x0044U         /* data REDO / fast fsync */
   #define HAMMER_HEAD_TYPE_45     0x0045U
   
   #define HAMMER_HEAD_FLAG_FREE   0x8000U         /* Indicates object freed */
   
   #define HAMMER_HEAD_SIGNATURE   0xC84EU
   #define HAMMER_TAIL_SIGNATURE   0xC74FU
   
   #define HAMMER_HEAD_SEQ_BEG     0x80000000U
   #define HAMMER_HEAD_SEQ_END     0x40000000U
   #define HAMMER_HEAD_SEQ_MASK    0x3FFFFFFFU
   
   /*
    * Misc FIFO structures.
    *
    * UNDO - Raw meta-data media updates.
    */
   struct hammer_fifo_undo {
           struct hammer_fifo_head head;
           hammer_off_t            undo_offset;    /* zone-1 offset */
           int32_t                 undo_data_bytes;
           int32_t                 undo_reserved01;
           /* followed by data */
   };
   
   /*
    * REDO (HAMMER version 4+) - Logical file writes/truncates.
    *
    * REDOs contain information which will be duplicated in a later meta-data
    * update, allowing fast write()+fsync() operations.  REDOs can be ignored
    * without harming filesystem integrity but must be processed if fsync()
    * semantics are desired.
    *
    * Unlike UNDOs which are processed backwards within the recovery span,
    * REDOs must be processed forwards starting further back (starting outside
    * the recovery span).
    *
    *      WRITE   - Write logical file (with payload).  Executed both
    *                out-of-span and in-span.  Out-of-span WRITEs may be
    *                filtered out by TERMs.
    *
    *      TRUNC   - Truncate logical file (no payload).  Executed both
    *                out-of-span and in-span.  Out-of-span WRITEs may be
    *                filtered out by TERMs.
    *
    *      TERM_*  - Indicates meta-data was committed (if out-of-span) or
    *                will be rolled-back (in-span).  Any out-of-span TERMs
    *                matching earlier WRITEs remove those WRITEs from
    *                consideration as they might conflict with a later data
    *                commit (which is not being rolled-back).
    *
    *      SYNC    - The earliest in-span SYNC (the last one when scanning
    *                backwards) tells the recovery code how far out-of-span
    *                it must go to run REDOs.
    *
    * NOTE: WRITEs do not always have matching TERMs even under
    *       perfect conditions because truncations might remove the
    *       buffers from consideration.  I/O problems can also remove
    *       buffers from consideration.
    *
    *       TRUNCSs do not always have matching TERMs because several
    *       truncations may be aggregated together into a single TERM.
    */
   struct hammer_fifo_redo {
           struct hammer_fifo_head head;
           int64_t                 redo_objid;     /* file being written */
           hammer_off_t            redo_offset;    /* logical offset in file */
           int32_t                 redo_data_bytes;
           u_int32_t               redo_flags;
           u_int32_t               redo_localization;
           u_int32_t               redo_reserved;
           u_int64_t               redo_mtime;     /* set mtime */
   };
   
   #define HAMMER_REDO_WRITE       0x00000001
   #define HAMMER_REDO_TRUNC       0x00000002
   #define HAMMER_REDO_TERM_WRITE  0x00000004
   #define HAMMER_REDO_TERM_TRUNC  0x00000008
   #define HAMMER_REDO_SYNC        0x00000010
   
   union hammer_fifo_any {
           struct hammer_fifo_head head;
           struct hammer_fifo_undo undo;
           struct hammer_fifo_redo redo;
   };
   
   typedef struct hammer_fifo_redo *hammer_fifo_redo_t;
   typedef struct hammer_fifo_undo *hammer_fifo_undo_t;
   typedef union hammer_fifo_any *hammer_fifo_any_t;
   
   /*
    * Volume header types
    */
   #define HAMMER_FSBUF_VOLUME     0xC8414D4DC5523031ULL   /* HAMMER01 */
   #define HAMMER_FSBUF_VOLUME_REV 0x313052C54D4D41C8ULL   /* (reverse endian) */
   
   /*
    * The B-Tree structures need hammer_fsbuf_head.
    */
   #include "hammer_btree.h"
   
   /*
    * HAMMER Volume header
    *
    * A HAMMER filesystem is built from any number of block devices,  Each block
    * device contains a volume header followed by however many buffers fit
    * into the volume.
    *
    * One of the volumes making up a HAMMER filesystem is the master, the
    * rest are slaves.  It does not have to be volume #0.
    *
    * The volume header takes up an entire 16K filesystem buffer and may
    * represent up to 64KTB (65536 TB) of space.
    *
    * Special field notes:
    *
    *      vol_bot_beg - offset of boot area (mem_beg - bot_beg bytes)
    *      vol_mem_beg - offset of memory log (clu_beg - mem_beg bytes)
    *      vol_buf_beg - offset of the first buffer.
    *
    *      The memory log area allows a kernel to cache new records and data
    *      in memory without allocating space in the actual filesystem to hold
    *      the records and data.  In the event that a filesystem becomes full,
    *      any records remaining in memory can be flushed to the memory log
    *      area.  This allows the kernel to immediately return success.
    */
   
   #define HAMMER_BOOT_MINBYTES            (32*1024)
   #define HAMMER_BOOT_NOMBYTES            (64LL*1024*1024)
   #define HAMMER_BOOT_MAXBYTES            (256LL*1024*1024)
   
   #define HAMMER_MEM_MINBYTES             (256*1024)
   #define HAMMER_MEM_NOMBYTES             (1LL*1024*1024*1024)
   #define HAMMER_MEM_MAXBYTES             (64LL*1024*1024*1024)
   
   struct hammer_volume_ondisk {
           u_int64_t vol_signature;/* Signature */
   
           int64_t vol_bot_beg;    /* byte offset of boot area or 0 */
           int64_t vol_mem_beg;    /* byte offset of memory log or 0 */
           int64_t vol_buf_beg;    /* byte offset of first buffer in volume */
           int64_t vol_buf_end;    /* byte offset of volume EOF (on buf bndry) */
           int64_t vol_locked;     /* reserved clusters are >= this offset */
   
           uuid_t    vol_fsid;     /* identify filesystem */
           uuid_t    vol_fstype;   /* identify filesystem type */
           char      vol_name[64]; /* Name of volume */
   
           int32_t vol_no;         /* volume number within filesystem */
           int32_t vol_count;      /* number of volumes making up FS */
   
           u_int32_t vol_version;  /* version control information */
           hammer_crc_t vol_crc;   /* header crc */
           u_int32_t vol_flags;    /* volume flags */
           u_int32_t vol_rootvol;  /* which volume is the root volume? */
   
           int32_t vol_reserved04;
           int32_t vol_reserved05;
           u_int32_t vol_reserved06;
           u_int32_t vol_reserved07;
   
           int32_t vol_blocksize;          /* for statfs only */
           int32_t vol_reserved08;
           int64_t vol_nblocks;            /* total allocatable hammer bufs */
   
           /*
            * These fields are initialized and space is reserved in every
            * volume making up a HAMMER filesytem, but only the master volume
            * contains valid data.
            */
           int64_t vol0_stat_bigblocks;    /* total bigblocks when fs is empty */
           int64_t vol0_stat_freebigblocks;/* number of free bigblocks */
           int64_t vol0_stat_bytes;        /* for statfs only */
           int64_t vol0_stat_inodes;       /* for statfs only */
           int64_t vol0_stat_records;      /* total records in filesystem */
           hammer_off_t vol0_btree_root;   /* B-Tree root */
           hammer_tid_t vol0_next_tid;     /* highest partially synchronized TID */
           hammer_off_t vol0_unused03;
   
           /*
            * Blockmaps for zones.  Not all zones use a blockmap.  Note that
            * the entire root blockmap is cached in the hammer_mount structure.
            */
           struct hammer_blockmap  vol0_blockmap[HAMMER_MAX_ZONES];
   
           /*
            * Array of zone-2 addresses for undo FIFO.
            */
           hammer_off_t            vol0_undo_array[HAMMER_UNDO_LAYER2];
   
   };
   
   typedef struct hammer_volume_ondisk *hammer_volume_ondisk_t;
   
   #define HAMMER_VOLF_VALID               0x0001  /* valid entry */
   #define HAMMER_VOLF_OPEN                0x0002  /* volume is open */
   #define HAMMER_VOLF_NEEDFLUSH           0x0004  /* volume needs flush */
   
   #define HAMMER_VOL_CRCSIZE1     \
           offsetof(struct hammer_volume_ondisk, vol_crc)
   #define HAMMER_VOL_CRCSIZE2     \
           (sizeof(struct hammer_volume_ondisk) - HAMMER_VOL_CRCSIZE1 -    \
            sizeof(hammer_crc_t))
   
   #define HAMMER_VOL_VERSION_MIN          1       /* minimum supported version */
   #define HAMMER_VOL_VERSION_DEFAULT      6       /* newfs default version */
   #define HAMMER_VOL_VERSION_WIP          7       /* version >= this is WIP */
   #define HAMMER_VOL_VERSION_MAX          6       /* maximum supported version */
   
   #define HAMMER_VOL_VERSION_ONE          1
   #define HAMMER_VOL_VERSION_TWO          2       /* new dirent layout (2.3+) */
   #define HAMMER_VOL_VERSION_THREE        3       /* new snapshot layout (2.5+) */
   #define HAMMER_VOL_VERSION_FOUR         4       /* new undo/flush (2.5+) */
   #define HAMMER_VOL_VERSION_FIVE         5       /* dedup (2.9+) */
   #define HAMMER_VOL_VERSION_SIX          6       /* DIRHASH_ALG1 */
   
   /*
    * Record types are fairly straightforward.  The B-Tree includes the record
    * type in its index sort.
    */
   #define HAMMER_RECTYPE_UNKNOWN          0
   #define HAMMER_RECTYPE_LOWEST           1       /* lowest record type avail */
   #define HAMMER_RECTYPE_INODE            1       /* inode in obj_id space */
   #define HAMMER_RECTYPE_UNUSED02         2
   #define HAMMER_RECTYPE_UNUSED03         3
   #define HAMMER_RECTYPE_DATA             0x0010
   #define HAMMER_RECTYPE_DIRENTRY         0x0011
   #define HAMMER_RECTYPE_DB               0x0012
   #define HAMMER_RECTYPE_EXT              0x0013  /* ext attributes */
   #define HAMMER_RECTYPE_FIX              0x0014  /* fixed attribute */
   #define HAMMER_RECTYPE_PFS              0x0015  /* PFS management */
   #define HAMMER_RECTYPE_SNAPSHOT         0x0016  /* Snapshot management */
   #define HAMMER_RECTYPE_CONFIG           0x0017  /* hammer cleanup config */
   #define HAMMER_RECTYPE_MOVED            0x8000  /* special recovery flag */
   #define HAMMER_RECTYPE_MAX              0xFFFF
   
   #define HAMMER_RECTYPE_CLEAN_START      HAMMER_RECTYPE_EXT
   
   #define HAMMER_FIXKEY_SYMLINK           1
   
   #define HAMMER_OBJTYPE_UNKNOWN          0       /* (never exists on-disk) */
   #define HAMMER_OBJTYPE_DIRECTORY        1
   #define HAMMER_OBJTYPE_REGFILE          2
   #define HAMMER_OBJTYPE_DBFILE           3
   #define HAMMER_OBJTYPE_FIFO             4
   #define HAMMER_OBJTYPE_CDEV             5
   #define HAMMER_OBJTYPE_BDEV             6
   #define HAMMER_OBJTYPE_SOFTLINK         7
   #define HAMMER_OBJTYPE_PSEUDOFS         8       /* pseudo filesystem obj */
   #define HAMMER_OBJTYPE_SOCKET           9
   
   /*
    * HAMMER inode attribute data
    *
    * The data reference for a HAMMER inode points to this structure.  Any
    * modifications to the contents of this structure will result in a
    * replacement operation.
    *
    * parent_obj_id is only valid for directories (which cannot be hard-linked),
    * and specifies the parent directory obj_id.  This field will also be set
    * for non-directory inodes as a recovery aid, but can wind up holding
    * stale information.  However, since object id's are not reused, the worse
    * that happens is that the recovery code is unable to use it.
    *
    * NOTE: Future note on directory hardlinks.  We can implement a record type
    * which allows us to point to multiple parent directories.
    *
    * NOTE: atime is stored in the inode's B-Tree element and not in the inode
    * data.  This allows the atime to be updated without having to lay down a
    * new record.
    */
   struct hammer_inode_data {
           u_int16_t version;      /* inode data version */
           u_int16_t mode;         /* basic unix permissions */
           u_int32_t uflags;       /* chflags */
           u_int32_t rmajor;       /* used by device nodes */
           u_int32_t rminor;       /* used by device nodes */
           u_int64_t ctime;
           int64_t parent_obj_id;  /* parent directory obj_id */
           uuid_t    uid;
           uuid_t    gid;
   
           u_int8_t  obj_type;
           u_int8_t  cap_flags;    /* capability support flags (extension) */
           u_int16_t reserved02;
           u_int32_t reserved03;   /* RESERVED FOR POSSIBLE FUTURE BIRTHTIME */
           u_int64_t nlinks;       /* hard links */
           u_int64_t size;         /* filesystem object size */
           union {
                   struct {
                           char    reserved06[16];
                           u_int32_t parent_obj_localization;
                           u_int32_t integrity_crc;
                   } obj;
                   char    symlink[24];    /* HAMMER_INODE_BASESYMLEN */
           } ext;
           u_int64_t mtime;        /* mtime must be second-to-last */
           u_int64_t atime;        /* atime must be last */
   };
   
   /*
    * Neither mtime nor atime upates are CRCd by the B-Tree element.
    * mtime updates have UNDO, atime updates do not.
    */
   #define HAMMER_ITIMES_BASE(ino_data)    (&(ino_data)->mtime)
   #define HAMMER_ITIMES_BYTES             (sizeof(u_int64_t) * 2)
   
   #define HAMMER_INODE_CRCSIZE    \
           offsetof(struct hammer_inode_data, mtime)
   
   #define HAMMER_INODE_DATA_VERSION       1
   #define HAMMER_OBJID_ROOT               1
   #define HAMMER_INODE_BASESYMLEN         24      /* see ext.symlink */
   
   /*
    * Capability & implementation flags.
    *
    * DIR_LOCAL_INO - Use inode B-Tree localization for directory entries.
    */
   #define HAMMER_INODE_CAP_DIRHASH_MASK   0x03    /* directory: hash algorithm */
   #define HAMMER_INODE_CAP_DIRHASH_ALG0   0x00
   #define HAMMER_INODE_CAP_DIRHASH_ALG1   0x01
   #define HAMMER_INODE_CAP_DIRHASH_ALG2   0x02
   #define HAMMER_INODE_CAP_DIRHASH_ALG3   0x03
   #define HAMMER_INODE_CAP_DIR_LOCAL_INO  0x04    /* use inode localization */
   
   /*
    * A HAMMER directory entry associates a HAMMER filesystem object with a
    * namespace.  It is possible to hook into a pseudo-filesystem (with its
    * own inode numbering space) in the filesystem by setting the high
    * 16 bits of the localization field.  The low 16 bits must be 0 and
    * are reserved for future use.
    *
    * Directory entries are indexed with a 128 bit namekey rather then an
    * offset.  A portion of the namekey is an iterator/randomizer to deal
    * with collisions.
    *
    * NOTE: base.base.obj_type from the related B-Tree leaf entry holds
    * the filesystem object type of obj_id, e.g. a den_type equivalent.
    * It is not stored in hammer_entry_data.
    *
    * NOTE: den_name / the filename data reference is NOT terminated with \0.
    */
   struct hammer_entry_data {
           int64_t obj_id;                 /* object being referenced */
           u_int32_t localization;         /* identify pseudo-filesystem */
           u_int32_t reserved02;
           char    name[16];               /* name (extended) */
   };
   
   #define HAMMER_ENTRY_NAME_OFF   offsetof(struct hammer_entry_data, name[0])
   #define HAMMER_ENTRY_SIZE(nlen) offsetof(struct hammer_entry_data, name[nlen])
   
   /*
    * Symlink data which does not fit in the inode is stored in a separte
    * FIX type record.
    */
   struct hammer_symlink_data {
           char    name[16];
   };
   
   #define HAMMER_SYMLINK_NAME_OFF offsetof(struct hammer_symlink_data, name[0])
   
   /*
    * The root inode for the primary filesystem and root inode for any
    * pseudo-fs may be tagged with an optional data structure using
    * HAMMER_RECTYPE_FIX/HAMMER_FIXKEY_PSEUDOFS.  This structure allows
    * the node to be used as a mirroring master or slave.
    *
    * When operating as a slave CD's into the node automatically become read-only
    * and as-of sync_end_tid.
    *
    * When operating as a master the read PFSD info sets sync_end_tid to
    * the most recently flushed TID.
    *
    * sync_low_tid is not yet used but will represent the highest pruning
    * end-point, after which full history is available.
    *
    * We need to pack this structure making it equally sized on both 32-bit and
    * 64-bit machines as it is part of struct hammer_ioc_mrecord_pfs which is
    * send over the wire in hammer mirror operations. Only on 64-bit machines
    * the size of this struct differ when packed or not. This leads us to the
    * situation where old 64-bit systems (using the non-packed structure),
    * which were never able to mirror to/from 32-bit systems, are now no longer
    * able to mirror to/from newer 64-bit systems (using the packed structure).
    */
   struct hammer_pseudofs_data {
           hammer_tid_t    sync_low_tid;   /* full history beyond this point */
           hammer_tid_t    sync_beg_tid;   /* earliest tid w/ full history avail */
           hammer_tid_t    sync_end_tid;   /* current synchronizatoin point */
           u_int64_t       sync_beg_ts;    /* real-time of last completed sync */
           u_int64_t       sync_end_ts;    /* initiation of current sync cycle */
           uuid_t          shared_uuid;    /* shared uuid (match required) */
           uuid_t          unique_uuid;    /* unique uuid of this master/slave */
           int32_t         reserved01;     /* reserved for future master_id */
           int32_t         mirror_flags;   /* misc flags */
           char            label[64];      /* filesystem space label */
           char            snapshots[64];  /* softlink dir for pruning */
           int16_t         prune_time;     /* how long to spend pruning */
           int16_t         prune_freq;     /* how often we prune */
           int16_t         reblock_time;   /* how long to spend reblocking */
           int16_t         reblock_freq;   /* how often we reblock */
           int32_t         snapshot_freq;  /* how often we create a snapshot */
           int32_t         prune_min;      /* do not prune recent history */
           int32_t         prune_max;      /* do not retain history beyond here */
           int32_t         reserved[16];
   } __packed;
   
   typedef struct hammer_pseudofs_data *hammer_pseudofs_data_t;
   
   #define HAMMER_PFSD_SLAVE       0x00000001
   #define HAMMER_PFSD_DELETED     0x80000000
   
   /*
    * Snapshot meta-data { Objid = HAMMER_OBJID_ROOT, Key = tid, rectype = SNAPSHOT }.
    *
    * Snapshot records replace the old <fs>/snapshots/<softlink> methodology.  Snapshot
    * records are mirrored but may be independantly managed once they are laid down on
    * a slave.
    *
    * NOTE: The b-tree key is signed, the tid is not, so callers must still sort the
    *       results.
    *
    * NOTE: Reserved fields must be zero (as usual)
    */
   struct hammer_snapshot_data {
           hammer_tid_t    tid;            /* the snapshot TID itself (== key) */
           u_int64_t       ts;             /* real-time when snapshot was made */
           u_int64_t       reserved01;
           u_int64_t       reserved02;
           char            label[64];      /* user-supplied description */
           u_int64_t       reserved03[4];
   };
   
   /*
    * Config meta-data { ObjId = HAMMER_OBJID_ROOT, Key = 0, rectype = CONFIG }.
    *
    * Used to store the hammer cleanup config.  This data is not mirrored.
    */
   struct hammer_config_data {
           char            text[1024];
   };
   
   /*
    * Rollup various structures embedded as record data
    */
   union hammer_data_ondisk {
           struct hammer_entry_data entry;
           struct hammer_inode_data inode;
           struct hammer_symlink_data symlink;
           struct hammer_pseudofs_data pfsd;
           struct hammer_snapshot_data snap;
           struct hammer_config_data config;
   };
   
   typedef union hammer_data_ondisk *hammer_data_ondisk_t;
   
   #endif

Cache object: 01b9f88e35ada0e36bebb8d5c1fda81f