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

     /*      $NetBSD: ext2fs.h,v 1.15 2004/03/22 19:23:08 bouyer Exp $       */
     
     /*
      * Copyright (c) 1982, 1986, 1993
      *      The Regents of the University of California.  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.
     * 3. Neither the name of the University 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 REGENTS 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 REGENTS 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.
     *
     *      @(#)fs.h        8.10 (Berkeley) 10/27/94
     *  Modified for ext2fs by Manuel Bouyer.
     */
    
    /*
     * Copyright (c) 1997 Manuel Bouyer.
     *
     * 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. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by Manuel Bouyer.
     * 4. The name of the author may not be used to endorse or promote products
     *    derived from this software without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
     *
     *      @(#)fs.h        8.10 (Berkeley) 10/27/94
     *  Modified for ext2fs by Manuel Bouyer.
     */
    
    #ifndef _UFS_EXT2FS_EXT2FS_H_
    #define _UFS_EXT2FS_EXT2FS_H_
    
    #include <machine/bswap.h>
    
    /*
     * Each disk drive contains some number of file systems.
     * A file system consists of a number of cylinder groups.
     * Each cylinder group has inodes and data.
     *
     * A file system is described by its super-block, which in turn
     * describes the cylinder groups.  The super-block is critical
     * data and is replicated in each cylinder group to protect against
     * catastrophic loss.  This is done at `newfs' time and the critical
     * super-block data does not change, so the copies need not be
     * referenced further unless disaster strikes.
     *
     * The first boot and super blocks are given in absolute disk addresses.
     * The byte-offset forms are preferred, as they don't imply a sector size.
     */
    #define BBSIZE          1024
    #define SBSIZE          1024
    #define BBOFF           ((off_t)(0))
    #define SBOFF           ((off_t)(BBOFF + BBSIZE))
    #define BBLOCK          ((daddr_t)(0))
    #define SBLOCK          ((daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE))
    
    /*
     * Addresses stored in inodes are capable of addressing blocks
     * XXX
     */
    
    /*
    * MINBSIZE is the smallest allowable block size.
    * MINBSIZE must be big enough to hold a cylinder group block,
    * thus changes to (struct cg) must keep its size within MINBSIZE.
    * Note that super blocks are always of size SBSIZE,
    * and that both SBSIZE and MAXBSIZE must be >= MINBSIZE.
    */
   #define LOG_MINBSIZE 10
   #define MINBSIZE        (1 << LOG_MINBSIZE)
   
   /*
    * 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
   
   /*
    * MINFREE gives the minimum acceptable percentage of file system
    * blocks which may be free. If the freelist drops below this level
    * only the superuser may continue to allocate blocks. This may
    * be set to 0 if no reserve of free blocks is deemed necessary,
    * however throughput drops by fifty percent if the file system
    * is run at between 95% and 100% full; thus the minimum default
    * value of fs_minfree is 5%. However, to get good clustering
    * performance, 10% is a better choice. hence we use 10% as our
    * default value. With 10% free space, fragmentation is not a
    * problem, so we choose to optimize for time.
    */
   #define MINFREE         5
   
   /*
    * Super block for an ext2fs file system.
    */
   struct ext2fs {
           u_int32_t  e2fs_icount;         /* Inode count */
           u_int32_t  e2fs_bcount;         /* blocks count */
           u_int32_t  e2fs_rbcount;        /* reserved blocks count */
           u_int32_t  e2fs_fbcount;        /* free blocks count */
           u_int32_t  e2fs_ficount;        /* free inodes count */
           u_int32_t  e2fs_first_dblock;   /* first data block */
           u_int32_t  e2fs_log_bsize;      /* block size = 1024*(2^e2fs_log_bsize) */
           u_int32_t  e2fs_fsize;          /* fragment size */
           u_int32_t  e2fs_bpg;            /* blocks per group */
           u_int32_t  e2fs_fpg;            /* frags per group */
           u_int32_t  e2fs_ipg;            /* inodes per group */
           u_int32_t  e2fs_mtime;          /* mount time */
           u_int32_t  e2fs_wtime;          /* write time */
           u_int16_t  e2fs_mnt_count;      /* mount count */
           u_int16_t  e2fs_max_mnt_count;  /* max mount count */
           u_int16_t  e2fs_magic;          /* magic number */
           u_int16_t  e2fs_state;          /* file system state */
           u_int16_t  e2fs_beh;            /* behavior on errors */
           u_int16_t  e2fs_minrev;         /* minor revision level */
           u_int32_t  e2fs_lastfsck;       /* time of last fsck */
           u_int32_t  e2fs_fsckintv;       /* max time between fscks */
           u_int32_t  e2fs_creator;        /* creator OS */
           u_int32_t  e2fs_rev;            /* revision level */
           u_int16_t  e2fs_ruid;           /* default uid for reserved blocks */
           u_int16_t  e2fs_rgid;           /* default gid for reserved blocks */
           /* EXT2_DYNAMIC_REV superblocks */
           u_int32_t  e2fs_first_ino;      /* first non-reserved inode */
           u_int16_t  e2fs_inode_size;     /* size of inode structure */
           u_int16_t  e2fs_block_group_nr; /* block grp number of this sblk*/
           u_int32_t  e2fs_features_compat; /*  compatible feature set */
           u_int32_t  e2fs_features_incompat; /* incompatible feature set */
           u_int32_t  e2fs_features_rocompat; /* RO-compatible feature set */
           u_int8_t   e2fs_uuid[16];       /* 128-bit uuid for volume */
           char       e2fs_vname[16];      /* volume name */
           char       e2fs_fsmnt[64];      /* name mounted on */
           u_int32_t  e2fs_algo;           /* For compression */
           u_int8_t   e2fs_prealloc;       /* # of blocks to preallocate */
           u_int8_t   e2fs_dir_prealloc;   /* # of blocks to preallocate for dir */
           u_int16_t  pad1;
           u_int32_t  reserved2[204];
   };
   
   
   /* in-memory data for ext2fs */
   struct m_ext2fs {
           struct ext2fs e2fs;
           u_char  e2fs_fsmnt[MAXMNTLEN];  /* name mounted on */
           int8_t  e2fs_ronly;     /* mounted read-only flag */
           int8_t  e2fs_fmod;      /* super block modified flag */
           int32_t e2fs_bsize;     /* block size */
           int32_t e2fs_bshift;    /* ``lblkno'' calc of logical blkno */
           int32_t e2fs_bmask;     /* ``blkoff'' calc of blk offsets */
           int64_t e2fs_qbmask;    /* ~fs_bmask - for use with quad size */
           int32_t e2fs_fsbtodb;   /* fsbtodb and dbtofsb shift constant */
           int32_t e2fs_ncg;       /* number of cylinder groups */
           int32_t e2fs_ngdb;      /* number of group descriptor block */
           int32_t e2fs_ipb;       /* number of inodes per block */
           int32_t e2fs_itpg;      /* number of inode table per group */
           struct  ext2_gd *e2fs_gd; /* group descripors */
   };
   
   
   
   /*
    * Filesystem identification
    */
   #define E2FS_MAGIC      0xef53  /* the ext2fs magic number */
   #define E2FS_REV0       0       /* revision levels */
   #define E2FS_REV1       1       /* revision levels */
   
   /* compatible/imcompatible features */
   #define EXT2F_COMPAT_PREALLOC           0x0001
   
   #define EXT2F_ROCOMPAT_SPARSESUPER      0x0001
   #define EXT2F_ROCOMPAT_LARGEFILE        0x0002
   #define EXT2F_ROCOMPAT_BTREE_DIR        0x0004
   
   #define EXT2F_INCOMPAT_COMP             0x0001
   #define EXT2F_INCOMPAT_FTYPE            0x0002
   
   /* features supported in this implementation */
   #define EXT2F_COMPAT_SUPP               0x0000
   #define EXT2F_ROCOMPAT_SUPP             EXT2F_ROCOMPAT_SPARSESUPER
   #define EXT2F_INCOMPAT_SUPP             EXT2F_INCOMPAT_FTYPE
   
   /*
    * OS identification
    */
   #define E2FS_OS_LINUX 0
   #define E2FS_OS_HURD  1
   #define E2FS_OS_MASIX 2
   
   /*
    * Filesystem clean flags
    */
   #define E2FS_ISCLEAN    0x01
   #define E2FS_ERRORS     0x02
   
   /* ext2 file system block group descriptor */
   
   struct ext2_gd {
           u_int32_t ext2bgd_b_bitmap;     /* blocks bitmap block */
           u_int32_t ext2bgd_i_bitmap;     /* inodes bitmap block */
           u_int32_t ext2bgd_i_tables;     /* inodes table block  */
           u_int16_t ext2bgd_nbfree;       /* number of free blocks */
           u_int16_t ext2bgd_nifree;       /* number of free inodes */
           u_int16_t ext2bgd_ndirs;        /* number of directories */
           u_int16_t reserved;
           u_int32_t reserved2[3];
   
   };
   
   
   /*
    * If the EXT2F_ROCOMPAT_SPARSESUPER flag is set, the cylinder group has a
    * copy of the super and cylinder group descriptors blocks only if it's
    * a power of 3, 5 or 7
    */
   
   static __inline__ int cg_has_sb __P((int)) __attribute__((__unused__));
   static __inline int
   cg_has_sb(i)
           int i;
   {
           int a3 ,a5 , a7;
   
           if (i == 0 || i == 1)
                   return 1;
           for (a3 = 3, a5 = 5, a7 = 7;
               a3 <= i || a5 <= i || a7 <= i;
               a3 *= 3, a5 *= 5, a7 *= 7)
                   if (i == a3 || i == a5 || i == a7)
                           return 1;
           return 0;
   }
   
   /* EXT2FS metadatas are stored in little-endian byte order. These macros
    * helps reading theses metadatas
    */
   
   #if BYTE_ORDER == LITTLE_ENDIAN
   #       define h2fs16(x) (x)
   #       define h2fs32(x) (x)
   #       define h2fs64(x) (x)
   #       define fs2h16(x) (x)
   #       define fs2h32(x) (x)
   #       define fs2h64(x) (x)
   #       define e2fs_sbload(old, new) memcpy((new), (old), SBSIZE);
   #       define e2fs_cgload(old, new, size) memcpy((new), (old), (size));
   #       define e2fs_sbsave(old, new) memcpy((new), (old), SBSIZE);
   #       define e2fs_cgsave(old, new, size) memcpy((new), (old), (size));
   #else
   void e2fs_sb_bswap __P((struct ext2fs *, struct ext2fs *));
   void e2fs_cg_bswap __P((struct ext2_gd *, struct ext2_gd *, int));
   #       define h2fs16(x) bswap16(x)
   #       define h2fs32(x) bswap32(x)
   #       define h2fs64(x) bswap64(x)
   #       define fs2h16(x) bswap16(x)
   #       define fs2h32(x) bswap32(x)
   #       define fs2h64(x) bswap64(x)
   #       define e2fs_sbload(old, new) e2fs_sb_bswap((old), (new))
   #       define e2fs_cgload(old, new, size) e2fs_cg_bswap((old), (new), (size));
   #       define e2fs_sbsave(old, new) e2fs_sb_bswap((old), (new))
   #       define e2fs_cgsave(old, new, size) e2fs_cg_bswap((old), (new), (size));
   #endif
   
   /*
    * Turn file system block numbers into disk block addresses.
    * This maps file system blocks to device size blocks.
    */
   #define fsbtodb(fs, b)  ((b) << (fs)->e2fs_fsbtodb)
   #define dbtofsb(fs, b)  ((b) >> (fs)->e2fs_fsbtodb)
   
   /*
    * Macros for handling inode numbers:
    *       inode number to file system block offset.
    *       inode number to cylinder group number.
    *       inode number to file system block address.
    */
   #define ino_to_cg(fs, x)        (((x) - 1) / (fs)->e2fs.e2fs_ipg)
   #define ino_to_fsba(fs, x)                                              \
           ((fs)->e2fs_gd[ino_to_cg(fs, x)].ext2bgd_i_tables + \
           (((x)-1) % (fs)->e2fs.e2fs_ipg)/(fs)->e2fs_ipb)
   #define ino_to_fsbo(fs, x)      (((x)-1) % (fs)->e2fs_ipb)
   
   /*
    * Give cylinder group number for a file system block.
    * Give cylinder group block number for a file system block.
    */
   #define dtog(fs, d) (((d) - (fs)->e2fs.e2fs_first_dblock) / (fs)->e2fs.e2fs_fpg)
   #define dtogd(fs, d) \
           (((d) - (fs)->e2fs.e2fs_first_dblock) % (fs)->e2fs.e2fs_fpg)
   
   /*
    * The following macros optimize certain frequently calculated
    * quantities by using shifts and masks in place of divisions
    * modulos and multiplications.
    */
   #define blkoff(fs, loc)         /* calculates (loc % fs->e2fs_bsize) */ \
           ((loc) & (fs)->e2fs_qbmask)
   #define lblktosize(fs, blk)     /* calculates (blk * fs->e2fs_bsize) */ \
           ((blk) << (fs)->e2fs_bshift)
   #define lblkno(fs, loc)         /* calculates (loc / fs->e2fs_bsize) */ \
           ((loc) >> (fs)->e2fs_bshift)
   #define blkroundup(fs, size)    /* calculates roundup(size, fs->e2fs_bsize) */ \
           (((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask)
   #define fragroundup(fs, size)   /* calculates roundup(size, fs->e2fs_bsize) */ \
           (((size) + (fs)->e2fs_qbmask) & (fs)->e2fs_bmask)
   /* 
    * Determine the number of available frags given a
    * percentage to hold in reserve.
    */   
   #define freespace(fs) \
      ((fs)->e2fs.e2fs_fbcount - (fs)->e2fs.e2fs_rbcount) 
   
   /*
    * Number of indirects in a file system block.
    */
   #define NINDIR(fs)      ((fs)->e2fs_bsize / sizeof(u_int32_t))
   
   #endif /* !_UFS_EXT2FS_EXT2FS_H_ */

Cache object: cba7e4ef881b11038cda7bb16c37de1e