FreeBSD/Linux Kernel Cross Reference
sys/fs/ext2fs/ext2fs.h

     /*-
      *  modified for EXT2FS support in Lites 1.1
      *
      *  Aug 1995, Godmar Back (gback@cs.utah.edu)
      *  University of Utah, Department of Computer Science
      *
      * $FreeBSD: releng/9.1/sys/fs/ext2fs/ext2fs.h 233322 2012-03-22 20:31:52Z pfg $
      */
     /*-
     * Copyright (c) 2009 Aditya Sarawgi
     * All rights reserved.
     *
     * 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.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
     *
     * 
     */
    
    #ifndef _FS_EXT2FS_EXT2FS_H_
    #define _FS_EXT2FS_EXT2FS_H_
    
    #include <sys/types.h>
    
    /*
     * Maximal count of links to a file
     */
    #define EXT2_LINK_MAX           32000
    
    /*
     * A summary of contiguous blocks of various sizes is maintained
     * in each cylinder group. Normally this is set by the initial
     * value of fs_maxcontig.
     *
     * XXX:FS_MAXCONTIG is set to 16 to conserve space. Here we set
     * EXT2_MAXCONTIG to 32 for better performance.
     */
    #define EXT2_MAXCONTIG          32
    
    /*
     * Constants relative to the data blocks
     */
    #define EXT2_NDIR_BLOCKS                12
    #define EXT2_IND_BLOCK                  EXT2_NDIR_BLOCKS
    #define EXT2_DIND_BLOCK                 (EXT2_IND_BLOCK + 1)
    #define EXT2_TIND_BLOCK                 (EXT2_DIND_BLOCK + 1)
    #define EXT2_N_BLOCKS                   (EXT2_TIND_BLOCK + 1)
    #define EXT2_MAXSYMLINKLEN              (EXT2_N_BLOCKS * sizeof(uint32_t))
    
    /*
     * The path name on which the file system is mounted is maintained
     * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in
     * the super block for this name.
     */
    #define MAXMNTLEN 512
    
    /*
     * Super block for an ext2fs file system.
     */
    struct ext2fs {
            uint32_t  e2fs_icount;          /* Inode count */
            uint32_t  e2fs_bcount;          /* blocks count */
            uint32_t  e2fs_rbcount;         /* reserved blocks count */
            uint32_t  e2fs_fbcount;         /* free blocks count */
            uint32_t  e2fs_ficount;         /* free inodes count */
            uint32_t  e2fs_first_dblock;    /* first data block */
            uint32_t  e2fs_log_bsize;       /* block size = 1024*(2^e2fs_log_bsize) */
            uint32_t  e2fs_log_fsize;       /* fragment size */
            uint32_t  e2fs_bpg;             /* blocks per group */
            uint32_t  e2fs_fpg;             /* frags per group */
            uint32_t  e2fs_ipg;             /* inodes per group */
            uint32_t  e2fs_mtime;           /* mount time */
            uint32_t  e2fs_wtime;           /* write time */
            uint16_t  e2fs_mnt_count;       /* mount count */
            uint16_t  e2fs_max_mnt_count;   /* max mount count */
            uint16_t  e2fs_magic;           /* magic number */
            uint16_t  e2fs_state;           /* file system state */
            uint16_t  e2fs_beh;             /* behavior on errors */
            uint16_t  e2fs_minrev;          /* minor revision level */
            uint32_t  e2fs_lastfsck;        /* time of last fsck */
            uint32_t  e2fs_fsckintv;        /* max time between fscks */
            uint32_t  e2fs_creator;         /* creator OS */
           uint32_t  e2fs_rev;             /* revision level */
           uint16_t  e2fs_ruid;            /* default uid for reserved blocks */
           uint16_t  e2fs_rgid;            /* default gid for reserved blocks */
           /* EXT2_DYNAMIC_REV superblocks */
           uint32_t  e2fs_first_ino;       /* first non-reserved inode */
           uint16_t  e2fs_inode_size;      /* size of inode structure */
           uint16_t  e2fs_block_group_nr;  /* block grp number of this sblk*/
           uint32_t  e2fs_features_compat; /*  compatible feature set */
           uint32_t  e2fs_features_incompat; /* incompatible feature set */
           uint32_t  e2fs_features_rocompat; /* RO-compatible feature set */
           uint8_t   e2fs_uuid[16];        /* 128-bit uuid for volume */
           char      e2fs_vname[16];       /* volume name */
           char      e2fs_fsmnt[64];       /* name mounted on */
           uint32_t  e2fs_algo;            /* For compression */
           uint8_t   e2fs_prealloc;        /* # of blocks for old prealloc */
           uint8_t   e2fs_dir_prealloc;    /* # of blocks for old prealloc dirs */
           uint16_t  e2fs_reserved_ngdb;   /* # of reserved gd blocks for resize */
           char      e3fs_journal_uuid[16]; /* uuid of journal superblock */
           uint32_t  e3fs_journal_inum;    /* inode number of journal file */
           uint32_t  e3fs_journal_dev;     /* device number of journal file */
           uint32_t  e3fs_last_orphan;     /* start of list of inodes to delete */
           uint32_t  e3fs_hash_seed[4];    /* HTREE hash seed */
           char      e3fs_def_hash_version; /* Default hash version to use */
           char      e3fs_reserved_char_pad;
           uint32_t  e3fs_default_mount_opts;
           uint32_t  e3fs_first_meta_bg;   /* First metablock block group */
           uint32_t  e3fs_mkfs_time;      /* when the fs was created */
           uint32_t  e3fs_jnl_blks[17];   /* backup of the journal inode */
           uint32_t  e4fs_bcount_hi;      /* block count */
           uint32_t  e4fs_rbcount_hi;     /* reserved blocks count */
           uint32_t  e4fs_fbcount_hi;     /* free blocks count */
           uint16_t  e4fs_min_extra_isize;/* all inodes have at least some bytes */
           uint16_t  e4fs_want_extra_isize; /* inodes must reserve some bytes */
           uint32_t  e4fs_flags;     /* miscellaneous flags */
           uint16_t  e4fs_raid_stride;    /* RAID stride */
           uint16_t  e4fs_mmpintv; /* number of seconds to wait in MMP checking */
           uint64_t  e4fs_mmpblk;   /* block for multi-mount protection */
           uint32_t  e4fs_raid_stripe_wid;/* blocks on all data disks (N * stride) */
           uint8_t   e4fs_log_gpf; /* FLEX_BG group size */ 
           uint8_t   e4fs_char_pad2;
           uint16_t  e4fs_pad;
           uint32_t  reserved2[162];       /* Padding to the end of the block */   
   };
   
   
   /*
    * In-Memory Superblock
    */
   
   struct m_ext2fs {
           struct ext2fs * e2fs;
           char     e2fs_fsmnt[MAXMNTLEN];/* name mounted on */
           char     e2fs_ronly;      /* mounted read-only flag */
           char     e2fs_fmod;       /* super block modified flag */
           uint32_t e2fs_bsize;      /* Block size */
           uint32_t e2fs_bshift;     /* calc of logical block no */
           int32_t  e2fs_bmask;      /* calc of block offset */
           int32_t  e2fs_bpg;        /* Number of blocks per group */
           int64_t  e2fs_qbmask;     /* = s_blocksize -1 */
           uint32_t e2fs_fsbtodb;    /* Shift to get disk block */
           uint32_t e2fs_ipg;        /* Number of inodes per group */
           uint32_t e2fs_ipb;        /* Number of inodes per block */
           uint32_t e2fs_itpg;       /* Number of inode table per group */
           uint32_t e2fs_fsize;      /* Size of fragments per block */
           uint32_t e2fs_fpb;        /* Number of fragments per block */
           uint32_t e2fs_fpg;        /* Number of fragments per group */
           uint32_t e2fs_dbpg;       /* Number of descriptor blocks per group */
           uint32_t e2fs_descpb;     /* Number of group descriptors per block */
           uint32_t e2fs_gdbcount;   /* Number of group descriptors */
           uint32_t e2fs_gcount;     /* Number of groups */
           uint32_t e2fs_first_inode;/* First inode on fs */
           int32_t  e2fs_isize;      /* Size of inode */
           uint32_t e2fs_mount_opt;
           uint32_t e2fs_blocksize_bits;
           uint32_t e2fs_total_dir;  /* Total number of directories */
           uint8_t *e2fs_contigdirs; /* (u) # of contig. allocated dirs */
           char     e2fs_wasvalid;   /* valid at mount time */
           off_t    e2fs_maxfilesize;
           struct   ext2_gd *e2fs_gd; /* Group Descriptors */
           int32_t  e2fs_maxcontig;        /* max number of contiguous blks */
           int32_t  e2fs_contigsumsize;    /* size of cluster summary array */
           int32_t *e2fs_maxcluster;       /* max cluster in each cyl group */
           struct   csum *e2fs_clustersum; /* cluster summary in each cyl group */
   };
   
   /*
    * The second extended file system version
    */
   #define E2FS_DATE               "95/08/09"
   #define E2FS_VERSION            "0.5b"
   
   /*
    * The second extended file system magic number
    */
   #define E2FS_MAGIC              0xEF53
   
   /*
    * Revision levels
    */
   #define E2FS_REV0               0       /* The good old (original) format */
   #define E2FS_REV1               1       /* V2 format w/ dynamic inode sizes */
   
   #define E2FS_CURRENT_REV        E2FS_REV0
   #define E2FS_MAX_SUPP_REV       E2FS_REV1
   
   #define E2FS_REV0_INODE_SIZE 128
   
   /*
    * compatible/incompatible features
    */
   #define EXT2F_COMPAT_PREALLOC           0x0001
   #define EXT2F_COMPAT_HASJOURNAL         0x0004
   #define EXT2F_COMPAT_RESIZE             0x0010
   
   #define EXT2F_ROCOMPAT_SPARSESUPER      0x0001
   #define EXT2F_ROCOMPAT_LARGEFILE        0x0002
   #define EXT2F_ROCOMPAT_BTREE_DIR        0x0004
   #define EXT4F_ROCOMPAT_EXTRA_ISIZE      0x0040
   
   #define EXT2F_INCOMPAT_COMP             0x0001
   #define EXT2F_INCOMPAT_FTYPE            0x0002
   
   /*
    * Features supported in this implementation
    *
    * We support the following REV1 features:
    * - EXT2F_ROCOMPAT_SPARSESUPER
    * - EXT2F_ROCOMPAT_LARGEFILE
    * - EXT2F_INCOMPAT_FTYPE
    */
   #define EXT2F_COMPAT_SUPP               0x0000
   #define EXT2F_ROCOMPAT_SUPP             (EXT2F_ROCOMPAT_SPARSESUPER | \
                                            EXT2F_ROCOMPAT_LARGEFILE | \
                                            EXT4F_ROCOMPAT_EXTRA_ISIZE)
   #define EXT2F_INCOMPAT_SUPP             EXT2F_INCOMPAT_FTYPE
   
   /* Assume that user mode programs are passing in an ext2fs superblock, not
    * a kernel struct super_block.  This will allow us to call the feature-test
    * macros from user land. */
   #define EXT2_SB(sb)     (sb)
   
   /*
    * Feature set definitions
    */
   #define EXT2_HAS_COMPAT_FEATURE(sb,mask)                        \
           ( EXT2_SB(sb)->e2fs->e2fs_features_compat & htole32(mask) )
   #define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask)                     \
           ( EXT2_SB(sb)->e2fs->e2fs_features_rocompat & htole32(mask) )
   #define EXT2_HAS_INCOMPAT_FEATURE(sb,mask)                      \
           ( EXT2_SB(sb)->e2fs->e2fs_features_incompat & htole32(mask) )
   
   /*
    * Definitions of behavior on errors
    */
   #define E2FS_BEH_CONTINUE               1       /* continue operation */
   #define E2FS_BEH_READONLY               2       /* remount fs read only */
   #define E2FS_BEH_PANIC                  3       /* cause panic */
   #define E2FS_BEH_DEFAULT                E2FS_BEH_CONTINUE
   
   /*
    * OS identification
    */
   #define E2FS_OS_LINUX           0
   #define E2FS_OS_HURD            1
   #define E2FS_OS_MASIX           2
   #define E2FS_OS_FREEBSD         3
   #define E2FS_OS_LITES           4
   
   /*
    * File clean flags
    */
   #define E2FS_ISCLEAN                    0x0001  /* Unmounted cleanly */
   #define E2FS_ERRORS                     0x0002  /* Errors detected */
   
   /* ext2 file system block group descriptor */
   
   struct ext2_gd {
           uint32_t ext2bgd_b_bitmap;      /* blocks bitmap block */
           uint32_t ext2bgd_i_bitmap;      /* inodes bitmap block */
           uint32_t ext2bgd_i_tables;      /* inodes table block  */
           uint16_t ext2bgd_nbfree;        /* number of free blocks */
           uint16_t ext2bgd_nifree;        /* number of free inodes */
           uint16_t ext2bgd_ndirs; /* number of directories */
           uint16_t reserved;
           uint32_t reserved2[3];
   };
   
   /* cluster summary information */
   
   struct csum {
           int8_t   cs_init; /* cluster summary has been initialized */
           int32_t *cs_sum;  /* cluster summary array */
   };
   
   /* EXT2FS metadatas are stored in little-endian byte order. These macros
    * helps reading these metadatas
    */
   
   #define e2fs_cgload(old, new, size) memcpy((new), (old), (size));
   #define e2fs_cgsave(old, new, size) memcpy((new), (old), (size));
   
   /*
    * Macro-instructions used to manage several block sizes
    */
   #define EXT2_MIN_BLOCK_SIZE             1024
   #define EXT2_MAX_BLOCK_SIZE             4096
   #define EXT2_MIN_BLOCK_LOG_SIZE           10
   #if defined(_KERNEL)
   # define EXT2_BLOCK_SIZE(s)             ((s)->e2fs_bsize)
   #else
   # define EXT2_BLOCK_SIZE(s)             (EXT2_MIN_BLOCK_SIZE << (s)->e2fs_log_bsize)
   #endif
   #define EXT2_ADDR_PER_BLOCK(s)          (EXT2_BLOCK_SIZE(s) / sizeof(uint32_t))
   #if defined(_KERNEL)
   # define EXT2_BLOCK_SIZE_BITS(s)        ((s)->e2fs_blocksize_bits)
   #else
   # define EXT2_BLOCK_SIZE_BITS(s)        ((s)->e2fs_log_bsize + 10)
   #endif
   #if defined(_KERNEL)
   #define EXT2_ADDR_PER_BLOCK_BITS(s)     (EXT2_SB(s)->s_addr_per_block_bits)
   #define EXT2_INODE_SIZE(s)              (EXT2_SB(s)->e2fs_isize)
   #define EXT2_FIRST_INO(s)               (EXT2_SB(s)->e2fs_first_inode)
   #else
   #define EXT2_INODE_SIZE(s)      (((s)->s_rev_level == E2FS_REV0) ? \
                                    E2FS_REV0 : (s)->s_inode_size)
   #define EXT2_FIRST_INO(s)       (((s)->s_rev_level == E2FS_REV0) ? \
                                    E2FS_REV0 : (s)->e2fs_first_ino)
   #endif
   
   /*
    * Macro-instructions used to manage fragments
    */
   #define EXT2_MIN_FRAG_SIZE              1024
   #define EXT2_MAX_FRAG_SIZE              4096
   #define EXT2_MIN_FRAG_LOG_SIZE            10
   #if defined(_KERNEL)
   # define EXT2_FRAG_SIZE(s)              (EXT2_SB(s)->e2fs_fsize)
   # define EXT2_FRAGS_PER_BLOCK(s)        (EXT2_SB(s)->e2fs_fpb)
   #else
   # define EXT2_FRAG_SIZE(s)              (EXT2_MIN_FRAG_SIZE << (s)->e2fs_log_fsize)
   # define EXT2_FRAGS_PER_BLOCK(s)        (EXT2_BLOCK_SIZE(s) / EXT2_FRAG_SIZE(s))
   #endif
   
   /*
    * Macro-instructions used to manage group descriptors
    */
   #if defined(_KERNEL)
   # define EXT2_BLOCKS_PER_GROUP(s)       (EXT2_SB(s)->e2fs_bpg)
   # define EXT2_DESC_PER_BLOCK(s)         (EXT2_SB(s)->e2fs_descpb)
   # define EXT2_DESC_PER_BLOCK_BITS(s)    (EXT2_SB(s)->s_desc_per_block_bits)
   #else
   # define EXT2_BLOCKS_PER_GROUP(s)       ((s)->e2fs_bpg)
   # define EXT2_DESC_PER_BLOCK(s)         (EXT2_BLOCK_SIZE(s) / sizeof(struct ext2_gd))
   
   #endif
   
   #endif  /* !_FS_EXT2FS_EXT2FS_H_ */

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