The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/ufs/ffs/fs.h

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    1 /*-
    2  * SPDX-License-Identifier: BSD-3-Clause
    3  *
    4  * Copyright (c) 1982, 1986, 1993
    5  *      The Regents of the University of California.  All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  * 3. Neither the name of the University nor the names of its contributors
   16  *    may be used to endorse or promote products derived from this software
   17  *    without specific prior written permission.
   18  *
   19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   29  * SUCH DAMAGE.
   30  *
   31  *      @(#)fs.h        8.13 (Berkeley) 3/21/95
   32  * $FreeBSD$
   33  */
   34 
   35 #ifndef _UFS_FFS_FS_H_
   36 #define _UFS_FFS_FS_H_
   37 
   38 #include <sys/mount.h>
   39 #include <ufs/ufs/dinode.h>
   40 
   41 /*
   42  * Each disk drive contains some number of filesystems.
   43  * A filesystem consists of a number of cylinder groups.
   44  * Each cylinder group has inodes and data.
   45  *
   46  * A filesystem is described by its super-block, which in turn
   47  * describes the cylinder groups.  The super-block is critical
   48  * data and is replicated in each cylinder group to protect against
   49  * catastrophic loss.  This is done at `newfs' time and the critical
   50  * super-block data does not change, so the copies need not be
   51  * referenced further unless disaster strikes.
   52  *
   53  * For filesystem fs, the offsets of the various blocks of interest
   54  * are given in the super block as:
   55  *      [fs->fs_sblkno]         Super-block
   56  *      [fs->fs_cblkno]         Cylinder group block
   57  *      [fs->fs_iblkno]         Inode blocks
   58  *      [fs->fs_dblkno]         Data blocks
   59  * The beginning of cylinder group cg in fs, is given by
   60  * the ``cgbase(fs, cg)'' macro.
   61  *
   62  * Depending on the architecture and the media, the superblock may
   63  * reside in any one of four places. For tiny media where every block 
   64  * counts, it is placed at the very front of the partition. Historically,
   65  * UFS1 placed it 8K from the front to leave room for the disk label and
   66  * a small bootstrap. For UFS2 it got moved to 64K from the front to leave
   67  * room for the disk label and a bigger bootstrap, and for really piggy
   68  * systems we check at 256K from the front if the first three fail. In
   69  * all cases the size of the superblock will be SBLOCKSIZE. All values are
   70  * given in byte-offset form, so they do not imply a sector size. The
   71  * SBLOCKSEARCH specifies the order in which the locations should be searched.
   72  */
   73 #define SBLOCK_FLOPPY        0
   74 #define SBLOCK_UFS1       8192
   75 #define SBLOCK_UFS2      65536
   76 #define SBLOCK_PIGGY    262144
   77 #define SBLOCKSIZE        8192
   78 #define SBLOCKSEARCH \
   79         { SBLOCK_UFS2, SBLOCK_UFS1, SBLOCK_FLOPPY, SBLOCK_PIGGY, -1 }
   80 /*
   81  * Request standard superblock location in ffs_sbget().
   82  */
   83 #define UFS_STDSB       -1      /* Search standard places for superblock */
   84 
   85 /*
   86  * UFS_NOMSG indicates that superblock inconsistency error messages
   87  *    should not be printed. It is used by programs like fsck that
   88  *    want to print their own error message.
   89  *
   90  * UFS_NOCSUM causes only the superblock itself to be returned, but does
   91  *    not read in any auxiliary data structures like the cylinder group
   92  *    summary information. It is used by clients like glabel that just
   93  *    want to check for possible filesystem types. Using UFS_NOCSUM
   94  *    skips the superblock checks for csum data which allows superblocks
   95  *    that have corrupted csum data to be read and used.
   96  *
   97  * UFS_NOHASHFAIL will note that the check hash is wrong but will still
   98  *    return the superblock. This is used by the bootstrap code to
   99  *    give the system a chance to come up so that fsck can be run to
  100  *    correct the problem.
  101  *
  102  * UFS_NOWARNFAIL will warn about inconsistencies but still return the
  103  *    superblock. It includes UFS_NOHASHFAIL. UFS_NOWARNFAIL is used by
  104  *    programs like fsck_ffs(8) to debug broken filesystems.
  105  *
  106  * UFS_FSRONLY will only validate the superblock fields needed to
  107  *    calculate where the backup filesystem superblocks are located.
  108  *    If these values pass their validation tests, then the superblock
  109  *    is returned. This flag is used as part of the attempt to find
  110  *    alternate superblocks when using ffs_sbsearch().
  111  */
  112 #define UFS_NOHASHFAIL  0x0001  /* Ignore check-hash failure */
  113 #define UFS_NOWARNFAIL  0x0003  /* Ignore non-fatal inconsistencies */
  114 #define UFS_NOMSG       0x0004  /* Print no error message */
  115 #define UFS_NOCSUM      0x0008  /* Read just the superblock without csum */
  116 #define UFS_FSRONLY     0x0010  /* Validate only values needed for recovery
  117                                    of alternate superblocks */
  118 #define UFS_ALTSBLK     0x1000  /* Flag used internally */
  119 
  120 /*
  121  * Max number of fragments per block. This value is NOT tweakable.
  122  */
  123 #define MAXFRAG         8
  124 
  125 /*
  126  * Addresses stored in inodes are capable of addressing fragments
  127  * of `blocks'. File system blocks of at most size MAXBSIZE can
  128  * be optionally broken into 2, 4, or 8 pieces, each of which is
  129  * addressable; these pieces may be DEV_BSIZE, or some multiple of
  130  * a DEV_BSIZE unit.
  131  *
  132  * Large files consist of exclusively large data blocks.  To avoid
  133  * undue wasted disk space, the last data block of a small file may be
  134  * allocated as only as many fragments of a large block as are
  135  * necessary.  The filesystem format retains only a single pointer
  136  * to such a fragment, which is a piece of a single large block that
  137  * has been divided.  The size of such a fragment is determinable from
  138  * information in the inode, using the ``blksize(fs, ip, lbn)'' macro.
  139  *
  140  * The filesystem records space availability at the fragment level;
  141  * to determine block availability, aligned fragments are examined.
  142  */
  143 
  144 /*
  145  * MINBSIZE is the smallest allowable block size.
  146  * In order to insure that it is possible to create files of size
  147  * 2^32 with only two levels of indirection, MINBSIZE is set to 4096.
  148  * MINBSIZE must be big enough to hold a cylinder group block,
  149  * thus changes to (struct cg) must keep its size within MINBSIZE.
  150  * Note that super blocks are always of size SBLOCKSIZE,
  151  * and that both SBLOCKSIZE and MAXBSIZE must be >= MINBSIZE.
  152  */
  153 #define MINBSIZE        4096
  154 
  155 /*
  156  * The path name on which the filesystem is mounted is maintained
  157  * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in
  158  * the super block for this name.
  159  */
  160 #define MAXMNTLEN       468
  161 
  162 /*
  163  * The volume name for this filesystem is maintained in fs_volname.
  164  * MAXVOLLEN defines the length of the buffer allocated.
  165  */
  166 #define MAXVOLLEN       32
  167 
  168 /*
  169  * There is a 128-byte region in the superblock reserved for in-core
  170  * pointers to summary information. Originally this included an array
  171  * of pointers to blocks of struct csum; now there are just a few
  172  * pointers and the remaining space is padded with fs_ocsp[].
  173  *
  174  * NOCSPTRS determines the size of this padding. Historically this
  175  * space was used to store pointers to structures that summaried
  176  * filesystem usage and layout information. However, these pointers
  177  * left various kernel pointers in the superblock which made otherwise
  178  * identical superblocks appear to have differences. So, all the
  179  * pointers in the superblock were moved to a fs_summary_info structure
  180  * reducing the superblock to having only a single pointer to this
  181  * structure. When writing the superblock to disk, this pointer is
  182  * temporarily NULL'ed out so that the kernel pointer will not appear
  183  * in the on-disk copy of the superblock.
  184  */
  185 #define NOCSPTRS        ((128 / sizeof(void *)) - 1)
  186 
  187 /*
  188  * A summary of contiguous blocks of various sizes is maintained
  189  * in each cylinder group. Normally this is set by the initial
  190  * value of fs_maxcontig. To conserve space, a maximum summary size
  191  * is set by FS_MAXCONTIG.
  192  */
  193 #define FS_MAXCONTIG    16
  194 
  195 /*
  196  * MINFREE gives the minimum acceptable percentage of filesystem
  197  * blocks which may be free. If the freelist drops below this level
  198  * only the superuser may continue to allocate blocks. This may
  199  * be set to 0 if no reserve of free blocks is deemed necessary,
  200  * however throughput drops by fifty percent if the filesystem
  201  * is run at between 95% and 100% full; thus the minimum default
  202  * value of fs_minfree is 5%. However, to get good clustering
  203  * performance, 10% is a better choice. hence we use 10% as our
  204  * default value. With 10% free space, fragmentation is not a
  205  * problem, so we choose to optimize for time.
  206  */
  207 #define MINFREE         8
  208 #define DEFAULTOPT      FS_OPTTIME
  209 
  210 /*
  211  * Grigoriy Orlov <gluk@ptci.ru> has done some extensive work to fine
  212  * tune the layout preferences for directories within a filesystem.
  213  * His algorithm can be tuned by adjusting the following parameters
  214  * which tell the system the average file size and the average number
  215  * of files per directory. These defaults are well selected for typical
  216  * filesystems, but may need to be tuned for odd cases like filesystems
  217  * being used for squid caches or news spools.
  218  */
  219 #define AVFILESIZ       16384   /* expected average file size */
  220 #define AFPDIR          64      /* expected number of files per directory */
  221 
  222 /*
  223  * The maximum number of snapshot nodes that can be associated
  224  * with each filesystem. This limit affects only the number of
  225  * snapshot files that can be recorded within the superblock so
  226  * that they can be found when the filesystem is mounted. However,
  227  * maintaining too many will slow the filesystem performance, so
  228  * having this limit is a good idea.
  229  */
  230 #define FSMAXSNAP 20
  231 
  232 /*
  233  * Used to identify special blocks in snapshots:
  234  *
  235  * BLK_NOCOPY - A block that was unallocated at the time the snapshot
  236  *      was taken, hence does not need to be copied when written.
  237  * BLK_SNAP - A block held by another snapshot that is not needed by this
  238  *      snapshot. When the other snapshot is freed, the BLK_SNAP entries
  239  *      are converted to BLK_NOCOPY. These are needed to allow fsck to
  240  *      identify blocks that are in use by other snapshots (which are
  241  *      expunged from this snapshot).
  242  */
  243 #define BLK_NOCOPY ((ufs2_daddr_t)(1))
  244 #define BLK_SNAP ((ufs2_daddr_t)(2))
  245 
  246 /*
  247  * Sysctl values for the fast filesystem.
  248  */
  249 #define FFS_ADJ_REFCNT           1      /* adjust inode reference count */
  250 #define FFS_ADJ_BLKCNT           2      /* adjust inode used block count */
  251 #define FFS_BLK_FREE             3      /* free range of blocks in map */
  252 #define FFS_DIR_FREE             4      /* free specified dir inodes in map */
  253 #define FFS_FILE_FREE            5      /* free specified file inodes in map */
  254 #define FFS_SET_FLAGS            6      /* set filesystem flags */
  255 #define FFS_ADJ_NDIR             7      /* adjust number of directories */
  256 #define FFS_ADJ_NBFREE           8      /* adjust number of free blocks */
  257 #define FFS_ADJ_NIFREE           9      /* adjust number of free inodes */
  258 #define FFS_ADJ_NFFREE          10      /* adjust number of free frags */
  259 #define FFS_ADJ_NUMCLUSTERS     11      /* adjust number of free clusters */
  260 #define FFS_SET_CWD             12      /* set current directory */
  261 #define FFS_SET_DOTDOT          13      /* set inode number for ".." */
  262 #define FFS_UNLINK              14      /* remove a name in the filesystem */
  263 /* Was FFS_SET_INODE            15 */
  264 /* Was FFS_SET_BUFOUTPUT        16 */
  265 #define FFS_SET_SIZE            17      /* set inode size */
  266 #define FFS_MAXID               17      /* number of valid ffs ids */
  267 
  268 /*
  269  * Command structure passed in to the filesystem to adjust filesystem values.
  270  */
  271 #define FFS_CMD_VERSION         0x19790518      /* version ID */
  272 struct fsck_cmd {
  273         int32_t version;        /* version of command structure */
  274         int32_t handle;         /* reference to filesystem to be changed */
  275         int64_t value;          /* inode or block number to be affected */
  276         int64_t size;           /* amount or range to be adjusted */
  277         int64_t spare;          /* reserved for future use */
  278 };
  279 
  280 /*
  281  * A recovery structure placed at the end of the boot block area by newfs
  282  * that can be used by fsck to search for alternate superblocks.
  283  */
  284 struct fsrecovery {
  285         int32_t fsr_magic;      /* magic number */
  286         int32_t fsr_fsbtodb;    /* fsbtodb and dbtofsb shift constant */
  287         int32_t fsr_sblkno;     /* offset of super-block in filesys */
  288         int32_t fsr_fpg;        /* blocks per group * fs_frag */
  289         u_int32_t fsr_ncg;      /* number of cylinder groups */
  290 };
  291 
  292 /*
  293  * Per cylinder group information; summarized in blocks allocated
  294  * from first cylinder group data blocks.  These blocks have to be
  295  * read in from fs_csaddr (size fs_cssize) in addition to the
  296  * super block.
  297  */
  298 struct csum {
  299         int32_t cs_ndir;                /* number of directories */
  300         int32_t cs_nbfree;              /* number of free blocks */
  301         int32_t cs_nifree;              /* number of free inodes */
  302         int32_t cs_nffree;              /* number of free frags */
  303 };
  304 struct csum_total {
  305         int64_t cs_ndir;                /* number of directories */
  306         int64_t cs_nbfree;              /* number of free blocks */
  307         int64_t cs_nifree;              /* number of free inodes */
  308         int64_t cs_nffree;              /* number of free frags */
  309         int64_t cs_numclusters;         /* number of free clusters */
  310         int64_t cs_spare[3];            /* future expansion */
  311 };
  312 
  313 /*
  314  * Pointers to super block summary information. Placed in a separate
  315  * structure so there is just one pointer in the superblock.
  316  *
  317  * The pointers in this structure are used as follows:
  318  *   fs_contigdirs references an array that tracks the creation of new
  319  *      directories
  320  *   fs_csp references a contiguous array of struct csum for
  321  *      all cylinder groups
  322  *   fs_maxcluster references an array of cluster sizes that is computed
  323  *      as cylinder groups are inspected
  324  *   fs_active is used when creating snapshots; it points to a bitmap
  325  *      of cylinder groups for which the free-block bitmap has changed
  326  *      since the snapshot operation began.
  327  */
  328 struct fs_summary_info {
  329         uint8_t *si_contigdirs;         /* (u) # of contig. allocated dirs */
  330         struct  csum *si_csp;           /* (u) cg summary info buffer */
  331         int32_t *si_maxcluster;         /* (u) max cluster in each cyl group */
  332         u_int   *si_active;             /* (u) used by snapshots to track fs */
  333 };
  334 #define fs_contigdirs   fs_si->si_contigdirs
  335 #define fs_csp          fs_si->si_csp
  336 #define fs_maxcluster   fs_si->si_maxcluster
  337 #define fs_active       fs_si->si_active
  338 
  339 /*
  340  * Super block for an FFS filesystem.
  341  */
  342 struct fs {
  343         int32_t  fs_firstfield;         /* historic filesystem linked list, */
  344         int32_t  fs_unused_1;           /*     used for incore super blocks */
  345         int32_t  fs_sblkno;             /* offset of super-block in filesys */
  346         int32_t  fs_cblkno;             /* offset of cyl-block in filesys */
  347         int32_t  fs_iblkno;             /* offset of inode-blocks in filesys */
  348         int32_t  fs_dblkno;             /* offset of first data after cg */
  349         int32_t  fs_old_cgoffset;       /* cylinder group offset in cylinder */
  350         int32_t  fs_old_cgmask;         /* used to calc mod fs_ntrak */
  351         int32_t  fs_old_time;           /* last time written */
  352         int32_t  fs_old_size;           /* number of blocks in fs */
  353         int32_t  fs_old_dsize;          /* number of data blocks in fs */
  354         u_int32_t fs_ncg;               /* number of cylinder groups */
  355         int32_t  fs_bsize;              /* size of basic blocks in fs */
  356         int32_t  fs_fsize;              /* size of frag blocks in fs */
  357         int32_t  fs_frag;               /* number of frags in a block in fs */
  358 /* these are configuration parameters */
  359         int32_t  fs_minfree;            /* minimum percentage of free blocks */
  360         int32_t  fs_old_rotdelay;       /* num of ms for optimal next block */
  361         int32_t  fs_old_rps;            /* disk revolutions per second */
  362 /* these fields can be computed from the others */
  363         int32_t  fs_bmask;              /* ``blkoff'' calc of blk offsets */
  364         int32_t  fs_fmask;              /* ``fragoff'' calc of frag offsets */
  365         int32_t  fs_bshift;             /* ``lblkno'' calc of logical blkno */
  366         int32_t  fs_fshift;             /* ``numfrags'' calc number of frags */
  367 /* these are configuration parameters */
  368         int32_t  fs_maxcontig;          /* max number of contiguous blks */
  369         int32_t  fs_maxbpg;             /* max number of blks per cyl group */
  370 /* these fields can be computed from the others */
  371         int32_t  fs_fragshift;          /* block to frag shift */
  372         int32_t  fs_fsbtodb;            /* fsbtodb and dbtofsb shift constant */
  373         int32_t  fs_sbsize;             /* actual size of super block */
  374         int32_t  fs_spare1[2];          /* old fs_csmask */
  375                                         /* old fs_csshift */
  376         int32_t  fs_nindir;             /* value of NINDIR */
  377         u_int32_t fs_inopb;             /* value of INOPB */
  378         int32_t  fs_old_nspf;           /* value of NSPF */
  379 /* yet another configuration parameter */
  380         int32_t  fs_optim;              /* optimization preference, see below */
  381         int32_t  fs_old_npsect;         /* # sectors/track including spares */
  382         int32_t  fs_old_interleave;     /* hardware sector interleave */
  383         int32_t  fs_old_trackskew;      /* sector 0 skew, per track */
  384         int32_t  fs_id[2];              /* unique filesystem id */
  385 /* sizes determined by number of cylinder groups and their sizes */
  386         int32_t  fs_old_csaddr;         /* blk addr of cyl grp summary area */
  387         int32_t  fs_cssize;             /* size of cyl grp summary area */
  388         int32_t  fs_cgsize;             /* cylinder group size */
  389         int32_t  fs_spare2;             /* old fs_ntrak */
  390         int32_t  fs_old_nsect;          /* sectors per track */
  391         int32_t  fs_old_spc;            /* sectors per cylinder */
  392         int32_t  fs_old_ncyl;           /* cylinders in filesystem */
  393         int32_t  fs_old_cpg;            /* cylinders per group */
  394         u_int32_t fs_ipg;               /* inodes per group */
  395         int32_t  fs_fpg;                /* blocks per group * fs_frag */
  396 /* this data must be re-computed after crashes */
  397         struct  csum fs_old_cstotal;    /* cylinder summary information */
  398 /* these fields are cleared at mount time */
  399         int8_t   fs_fmod;               /* super block modified flag */
  400         int8_t   fs_clean;              /* filesystem is clean flag */
  401         int8_t   fs_ronly;              /* mounted read-only flag */
  402         int8_t   fs_old_flags;          /* old FS_ flags */
  403         u_char   fs_fsmnt[MAXMNTLEN];   /* name mounted on */
  404         u_char   fs_volname[MAXVOLLEN]; /* volume name */
  405         u_int64_t fs_swuid;             /* system-wide uid */
  406         int32_t  fs_pad;                /* due to alignment of fs_swuid */
  407 /* these fields retain the current block allocation info */
  408         int32_t  fs_cgrotor;            /* last cg searched */
  409         void    *fs_ocsp[NOCSPTRS];     /* padding; was list of fs_cs buffers */
  410         struct   fs_summary_info *fs_si;/* In-core pointer to summary info */
  411         int32_t  fs_old_cpc;            /* cyl per cycle in postbl */
  412         int32_t  fs_maxbsize;           /* maximum blocking factor permitted */
  413         int64_t  fs_unrefs;             /* number of unreferenced inodes */
  414         int64_t  fs_providersize;       /* size of underlying GEOM provider */
  415         int64_t  fs_metaspace;          /* size of area reserved for metadata */
  416         int64_t  fs_sparecon64[13];     /* old rotation block list head */
  417         int64_t  fs_sblockactualloc;    /* byte offset of this superblock */
  418         int64_t  fs_sblockloc;          /* byte offset of standard superblock */
  419         struct  csum_total fs_cstotal;  /* (u) cylinder summary information */
  420         ufs_time_t fs_time;             /* last time written */
  421         int64_t  fs_size;               /* number of blocks in fs */
  422         int64_t  fs_dsize;              /* number of data blocks in fs */
  423         ufs2_daddr_t fs_csaddr;         /* blk addr of cyl grp summary area */
  424         int64_t  fs_pendingblocks;      /* (u) blocks being freed */
  425         u_int32_t fs_pendinginodes;     /* (u) inodes being freed */
  426         uint32_t fs_snapinum[FSMAXSNAP];/* list of snapshot inode numbers */
  427         u_int32_t fs_avgfilesize;       /* expected average file size */
  428         u_int32_t fs_avgfpdir;          /* expected # of files per directory */
  429         int32_t  fs_save_cgsize;        /* save real cg size to use fs_bsize */
  430         ufs_time_t fs_mtime;            /* Last mount or fsck time. */
  431         int32_t  fs_sujfree;            /* SUJ free list */
  432         int32_t  fs_sparecon32[21];     /* reserved for future constants */
  433         u_int32_t fs_ckhash;            /* if CK_SUPERBLOCK, its check-hash */
  434         u_int32_t fs_metackhash;        /* metadata check-hash, see CK_ below */
  435         int32_t  fs_flags;              /* see FS_ flags below */
  436         int32_t  fs_contigsumsize;      /* size of cluster summary array */ 
  437         int32_t  fs_maxsymlinklen;      /* max length of an internal symlink */
  438         int32_t  fs_old_inodefmt;       /* format of on-disk inodes */
  439         u_int64_t fs_maxfilesize;       /* maximum representable file size */
  440         int64_t  fs_qbmask;             /* ~fs_bmask for use with 64-bit size */
  441         int64_t  fs_qfmask;             /* ~fs_fmask for use with 64-bit size */
  442         int32_t  fs_state;              /* validate fs_clean field */
  443         int32_t  fs_old_postblformat;   /* format of positional layout tables */
  444         int32_t  fs_old_nrpos;          /* number of rotational positions */
  445         int32_t  fs_spare5[2];          /* old fs_postbloff */
  446                                         /* old fs_rotbloff */
  447         int32_t  fs_magic;              /* magic number */
  448 };
  449 
  450 /* Sanity checking. */
  451 #ifdef CTASSERT
  452 CTASSERT(sizeof(struct fs) == 1376);
  453 #endif
  454 
  455 /*
  456  * Filesystem identification
  457  */
  458 #define FS_UFS1_MAGIC   0x011954        /* UFS1 fast filesystem magic number */
  459 #define FS_UFS2_MAGIC   0x19540119      /* UFS2 fast filesystem magic number */
  460 #define FS_BAD_MAGIC    0x19960408      /* UFS incomplete newfs magic number */
  461 #define FS_42INODEFMT   -1              /* 4.2BSD inode format */
  462 #define FS_44INODEFMT   2               /* 4.4BSD inode format */
  463 
  464 /*
  465  * Preference for optimization.
  466  */
  467 #define FS_OPTTIME      0       /* minimize allocation time */
  468 #define FS_OPTSPACE     1       /* minimize disk fragmentation */
  469 
  470 /*
  471  * Filesystem flags.
  472  *
  473  * The FS_UNCLEAN flag is set by the kernel when the filesystem was
  474  * mounted with fs_clean set to zero. The FS_DOSOFTDEP flag indicates
  475  * that the filesystem should be managed by the soft updates code.
  476  * Note that the FS_NEEDSFSCK flag is set and cleared by the fsck
  477  * utility. It is set when background fsck finds an unexpected
  478  * inconsistency which requires a traditional foreground fsck to be
  479  * run. Such inconsistencies should only be found after an uncorrectable
  480  * disk error. The FS_NEEDSFSCK can also be set when a mounted filesystem
  481  * discovers an internal inconsistency such as freeing a freed inode.
  482  * A foreground fsck will clear the FS_NEEDSFSCK flag when it has
  483  * successfully cleaned up the filesystem. The kernel uses this
  484  * flag to enforce that inconsistent filesystems be mounted read-only.
  485  *
  486  * The FS_METACKHASH flag when set indicates that the kernel maintains
  487  * one or more check hashes. The actual set of supported check hashes
  488  * is stored in the fs_metackhash field. Kernels that do not support
  489  * check hashes clear the FS_METACKHASH flag to indicate that the
  490  * check hashes need to be rebuilt (by fsck) before they can be used.
  491  *
  492  * When a filesystem is mounted, any flags not included in FS_SUPPORTED
  493  * are cleared. This lets newer features know that the filesystem has
  494  * been run on an older version of the filesystem and thus that data
  495  * structures associated with those features are out-of-date and need
  496  * to be rebuilt.
  497  *
  498  * FS_ACLS indicates that POSIX.1e ACLs are administratively enabled
  499  * for the file system, so they should be loaded from extended attributes,
  500  * observed for access control purposes, and be administered by object
  501  * owners.  FS_NFS4ACLS indicates that NFSv4 ACLs are administratively
  502  * enabled.  This flag is mutually exclusive with FS_ACLS.  FS_MULTILABEL
  503  * indicates that the TrustedBSD MAC Framework should attempt to back MAC
  504  * labels into extended attributes on the file system rather than maintain
  505  * a single mount label for all objects.
  506  */
  507 #define FS_UNCLEAN      0x00000001 /* filesystem not clean at mount */
  508 #define FS_DOSOFTDEP    0x00000002 /* filesystem using soft dependencies */
  509 #define FS_NEEDSFSCK    0x00000004 /* filesystem needs sync fsck before mount */
  510 #define FS_SUJ          0x00000008 /* Filesystem using softupdate journal */
  511 #define FS_ACLS         0x00000010 /* file system has POSIX.1e ACLs enabled */
  512 #define FS_MULTILABEL   0x00000020 /* file system is MAC multi-label */
  513 #define FS_GJOURNAL     0x00000040 /* gjournaled file system */
  514 #define FS_FLAGS_UPDATED 0x0000080 /* flags have been moved to new location */
  515 #define FS_NFS4ACLS     0x00000100 /* file system has NFSv4 ACLs enabled */
  516 #define FS_METACKHASH   0x00000200 /* kernel supports metadata check hashes */
  517 #define FS_TRIM         0x00000400 /* issue BIO_DELETE for deleted blocks */
  518 #define FS_SUPPORTED    0x00FFFFFF /* supported flags, others cleared at mount*/
  519 /*
  520  * Things that we may someday support, but currently do not.
  521  * These flags are all cleared so we know if we ran on a kernel
  522  * that does not support them.
  523  */
  524 #define FS_INDEXDIRS    0x01000000 /* kernel supports indexed directories */
  525 #define FS_VARBLKSIZE   0x02000000 /* kernel supports variable block sizes */
  526 #define FS_COOLOPT1     0x04000000 /* kernel supports cool option 1 */
  527 #define FS_COOLOPT2     0x08000000 /* kernel supports cool option 2 */
  528 #define FS_COOLOPT3     0x10000000 /* kernel supports cool option 3 */
  529 #define FS_COOLOPT4     0x20000000 /* kernel supports cool option 4 */
  530 #define FS_COOLOPT5     0x40000000 /* kernel supports cool option 5 */
  531 #define FS_COOLOPT6     0x80000000 /* kernel supports cool option 6 */
  532 
  533 /*
  534  * The fs_metackhash field indicates the types of metadata check-hash
  535  * that are maintained for a filesystem. Not all filesystems check-hash
  536  * all metadata.
  537  */
  538 #define CK_SUPERBLOCK   0x0001  /* the superblock */
  539 #define CK_CYLGRP       0x0002  /* the cylinder groups */
  540 #define CK_INODE        0x0004  /* inodes */
  541 #define CK_INDIR        0x0008  /* indirect blocks */
  542 #define CK_DIR          0x0010  /* directory contents */
  543 #define CK_SUPPORTED    0x0007  /* supported flags, others cleared at mount */
  544 /*
  545  * The BX_FSPRIV buffer b_xflags are used to track types of data in buffers.
  546  */
  547 #define BX_SUPERBLOCK   0x00010000      /* superblock */
  548 #define BX_CYLGRP       0x00020000      /* cylinder groups */
  549 #define BX_INODE        0x00040000      /* inodes */
  550 #define BX_INDIR        0x00080000      /* indirect blocks */
  551 #define BX_DIR          0x00100000      /* directory contents */
  552 
  553 #define PRINT_UFS_BUF_XFLAGS "\2\25dir\24indir\23inode\22cylgrp\21superblock"
  554 
  555 /*
  556  * Macros to access bits in the fs_active array.
  557  */
  558 #define ACTIVECGNUM(fs, cg)     ((fs)->fs_active[(cg) / (NBBY * sizeof(int))])
  559 #define ACTIVECGOFF(cg)         (1 << ((cg) % (NBBY * sizeof(int))))
  560 #define ACTIVESET(fs, cg)       do {                                    \
  561         if ((fs)->fs_active)                                            \
  562                 ACTIVECGNUM((fs), (cg)) |= ACTIVECGOFF((cg));           \
  563 } while (0)
  564 #define ACTIVECLEAR(fs, cg)     do {                                    \
  565         if ((fs)->fs_active)                                            \
  566                 ACTIVECGNUM((fs), (cg)) &= ~ACTIVECGOFF((cg));          \
  567 } while (0)
  568 
  569 /*
  570  * The size of a cylinder group is calculated by CGSIZE. The maximum size
  571  * is limited by the fact that cylinder groups are at most one block.
  572  * Its size is derived from the size of the maps maintained in the
  573  * cylinder group and the (struct cg) size.
  574  */
  575 #define CGSIZE(fs) \
  576     /* base cg */       (sizeof(struct cg) + sizeof(int32_t) + \
  577     /* old btotoff */   (fs)->fs_old_cpg * sizeof(int32_t) + \
  578     /* old boff */      (fs)->fs_old_cpg * sizeof(u_int16_t) + \
  579     /* inode map */     howmany((fs)->fs_ipg, NBBY) + \
  580     /* block map */     howmany((fs)->fs_fpg, NBBY) +\
  581     /* if present */    ((fs)->fs_contigsumsize <= 0 ? 0 : \
  582     /* cluster sum */   (fs)->fs_contigsumsize * sizeof(int32_t) + \
  583     /* cluster map */   howmany(fragstoblks(fs, (fs)->fs_fpg), NBBY)))
  584 
  585 /*
  586  * The minimal number of cylinder groups that should be created.
  587  */
  588 #define MINCYLGRPS      4
  589 
  590 /*
  591  * Convert cylinder group to base address of its global summary info.
  592  */
  593 #define fs_cs(fs, indx) fs_csp[indx]
  594 
  595 /*
  596  * Cylinder group block for a filesystem.
  597  */
  598 #define CG_MAGIC        0x090255
  599 struct cg {
  600         int32_t  cg_firstfield;         /* historic cyl groups linked list */
  601         int32_t  cg_magic;              /* magic number */
  602         int32_t  cg_old_time;           /* time last written */
  603         u_int32_t cg_cgx;               /* we are the cgx'th cylinder group */
  604         int16_t  cg_old_ncyl;           /* number of cyl's this cg */
  605         int16_t  cg_old_niblk;          /* number of inode blocks this cg */
  606         u_int32_t cg_ndblk;             /* number of data blocks this cg */
  607         struct   csum cg_cs;            /* cylinder summary information */
  608         u_int32_t cg_rotor;             /* position of last used block */
  609         u_int32_t cg_frotor;            /* position of last used frag */
  610         u_int32_t cg_irotor;            /* position of last used inode */
  611         u_int32_t cg_frsum[MAXFRAG];    /* counts of available frags */
  612         int32_t  cg_old_btotoff;        /* (int32) block totals per cylinder */
  613         int32_t  cg_old_boff;           /* (u_int16) free block positions */
  614         u_int32_t cg_iusedoff;          /* (u_int8) used inode map */
  615         u_int32_t cg_freeoff;           /* (u_int8) free block map */
  616         u_int32_t cg_nextfreeoff;       /* (u_int8) next available space */
  617         u_int32_t cg_clustersumoff;     /* (u_int32) counts of avail clusters */
  618         u_int32_t cg_clusteroff;                /* (u_int8) free cluster map */
  619         u_int32_t cg_nclusterblks;      /* number of clusters this cg */
  620         u_int32_t cg_niblk;             /* number of inode blocks this cg */
  621         u_int32_t cg_initediblk;                /* last initialized inode */
  622         u_int32_t cg_unrefs;            /* number of unreferenced inodes */
  623         int32_t  cg_sparecon32[1];      /* reserved for future use */
  624         u_int32_t cg_ckhash;            /* check-hash of this cg */
  625         ufs_time_t cg_time;             /* time last written */
  626         int64_t  cg_sparecon64[3];      /* reserved for future use */
  627         u_int8_t cg_space[1];           /* space for cylinder group maps */
  628 /* actually longer */
  629 };
  630 
  631 /*
  632  * Macros for access to cylinder group array structures
  633  */
  634 #define cg_chkmagic(cgp) ((cgp)->cg_magic == CG_MAGIC)
  635 #define cg_inosused(cgp) \
  636     ((u_int8_t *)((u_int8_t *)(cgp) + (cgp)->cg_iusedoff))
  637 #define cg_blksfree(cgp) \
  638     ((u_int8_t *)((u_int8_t *)(cgp) + (cgp)->cg_freeoff))
  639 #define cg_clustersfree(cgp) \
  640     ((u_int8_t *)((u_int8_t *)(cgp) + (cgp)->cg_clusteroff))
  641 #define cg_clustersum(cgp) \
  642     ((int32_t *)((uintptr_t)(cgp) + (cgp)->cg_clustersumoff))
  643 
  644 /*
  645  * Turn filesystem block numbers into disk block addresses.
  646  * This maps filesystem blocks to device size blocks.
  647  */
  648 #define fsbtodb(fs, b)  ((daddr_t)(b) << (fs)->fs_fsbtodb)
  649 #define dbtofsb(fs, b)  ((b) >> (fs)->fs_fsbtodb)
  650 
  651 /*
  652  * Cylinder group macros to locate things in cylinder groups.
  653  * They calc filesystem addresses of cylinder group data structures.
  654  */
  655 #define cgbase(fs, c)   (((ufs2_daddr_t)(fs)->fs_fpg) * (c))
  656 #define cgdata(fs, c)   (cgdmin(fs, c) + (fs)->fs_metaspace)    /* data zone */
  657 #define cgmeta(fs, c)   (cgdmin(fs, c))                         /* meta data */
  658 #define cgdmin(fs, c)   (cgstart(fs, c) + (fs)->fs_dblkno)      /* 1st data */
  659 #define cgimin(fs, c)   (cgstart(fs, c) + (fs)->fs_iblkno)      /* inode blk */
  660 #define cgsblock(fs, c) (cgstart(fs, c) + (fs)->fs_sblkno)      /* super blk */
  661 #define cgtod(fs, c)    (cgstart(fs, c) + (fs)->fs_cblkno)      /* cg block */
  662 #define cgstart(fs, c)                                                  \
  663        ((fs)->fs_magic == FS_UFS2_MAGIC ? cgbase(fs, c) :               \
  664        (cgbase(fs, c) + (fs)->fs_old_cgoffset * ((c) & ~((fs)->fs_old_cgmask))))
  665 
  666 /*
  667  * Macros for handling inode numbers:
  668  *     inode number to filesystem block offset.
  669  *     inode number to cylinder group number.
  670  *     inode number to filesystem block address.
  671  */
  672 #define ino_to_cg(fs, x)        (((ino_t)(x)) / (fs)->fs_ipg)
  673 #define ino_to_fsba(fs, x)                                              \
  674         ((ufs2_daddr_t)(cgimin(fs, ino_to_cg(fs, (ino_t)(x))) +         \
  675             (blkstofrags((fs), ((((ino_t)(x)) % (fs)->fs_ipg) / INOPB(fs))))))
  676 #define ino_to_fsbo(fs, x)      (((ino_t)(x)) % INOPB(fs))
  677 
  678 /*
  679  * Give cylinder group number for a filesystem block.
  680  * Give cylinder group block number for a filesystem block.
  681  */
  682 #define dtog(fs, d)     ((d) / (fs)->fs_fpg)
  683 #define dtogd(fs, d)    ((d) % (fs)->fs_fpg)
  684 
  685 /*
  686  * Extract the bits for a block from a map.
  687  * Compute the cylinder and rotational position of a cyl block addr.
  688  */
  689 #define blkmap(fs, map, loc) \
  690     (((map)[(loc) / NBBY] >> ((loc) % NBBY)) & (0xff >> (NBBY - (fs)->fs_frag)))
  691 
  692 /*
  693  * The following macros optimize certain frequently calculated
  694  * quantities by using shifts and masks in place of divisions
  695  * modulos and multiplications.
  696  */
  697 #define blkoff(fs, loc)         /* calculates (loc % fs->fs_bsize) */ \
  698         ((loc) & (fs)->fs_qbmask)
  699 #define fragoff(fs, loc)        /* calculates (loc % fs->fs_fsize) */ \
  700         ((loc) & (fs)->fs_qfmask)
  701 #define lfragtosize(fs, frag)   /* calculates ((off_t)frag * fs->fs_fsize) */ \
  702         (((off_t)(frag)) << (fs)->fs_fshift)
  703 #define lblktosize(fs, blk)     /* calculates ((off_t)blk * fs->fs_bsize) */ \
  704         (((off_t)(blk)) << (fs)->fs_bshift)
  705 /* Use this only when `blk' is known to be small, e.g., < UFS_NDADDR. */
  706 #define smalllblktosize(fs, blk)    /* calculates (blk * fs->fs_bsize) */ \
  707         ((blk) << (fs)->fs_bshift)
  708 #define lblkno(fs, loc)         /* calculates (loc / fs->fs_bsize) */ \
  709         ((loc) >> (fs)->fs_bshift)
  710 #define numfrags(fs, loc)       /* calculates (loc / fs->fs_fsize) */ \
  711         ((loc) >> (fs)->fs_fshift)
  712 #define blkroundup(fs, size)    /* calculates roundup(size, fs->fs_bsize) */ \
  713         (((size) + (fs)->fs_qbmask) & (fs)->fs_bmask)
  714 #define fragroundup(fs, size)   /* calculates roundup(size, fs->fs_fsize) */ \
  715         (((size) + (fs)->fs_qfmask) & (fs)->fs_fmask)
  716 #define fragstoblks(fs, frags)  /* calculates (frags / fs->fs_frag) */ \
  717         ((frags) >> (fs)->fs_fragshift)
  718 #define blkstofrags(fs, blks)   /* calculates (blks * fs->fs_frag) */ \
  719         ((blks) << (fs)->fs_fragshift)
  720 #define fragnum(fs, fsb)        /* calculates (fsb % fs->fs_frag) */ \
  721         ((fsb) & ((fs)->fs_frag - 1))
  722 #define blknum(fs, fsb)         /* calculates rounddown(fsb, fs->fs_frag) */ \
  723         ((fsb) &~ ((fs)->fs_frag - 1))
  724 
  725 /*
  726  * Determine the number of available frags given a
  727  * percentage to hold in reserve.
  728  */
  729 #define freespace(fs, percentreserved) \
  730         (blkstofrags((fs), (fs)->fs_cstotal.cs_nbfree) + \
  731         (fs)->fs_cstotal.cs_nffree - \
  732         (((off_t)((fs)->fs_dsize)) * (percentreserved) / 100))
  733 
  734 /*
  735  * Determining the size of a file block in the filesystem.
  736  */
  737 #define blksize(fs, ip, lbn) \
  738         (((lbn) >= UFS_NDADDR || (ip)->i_size >= \
  739             (uint64_t)smalllblktosize(fs, (lbn) + 1)) \
  740             ? (fs)->fs_bsize \
  741             : (fragroundup(fs, blkoff(fs, (ip)->i_size))))
  742 #define sblksize(fs, size, lbn) \
  743         (((lbn) >= UFS_NDADDR || (size) >= ((lbn) + 1) << (fs)->fs_bshift) \
  744           ? (fs)->fs_bsize \
  745           : (fragroundup(fs, blkoff(fs, (size)))))
  746 
  747 /*
  748  * Number of indirects in a filesystem block.
  749  */
  750 #define NINDIR(fs)      ((fs)->fs_nindir)
  751 
  752 /*
  753  * Indirect lbns are aligned on UFS_NDADDR addresses where single indirects
  754  * are the negated address of the lowest lbn reachable, double indirects
  755  * are this lbn - 1 and triple indirects are this lbn - 2.  This yields
  756  * an unusual bit order to determine level.
  757  */
  758 static inline int
  759 lbn_level(ufs_lbn_t lbn)
  760 {
  761         if (lbn >= 0)
  762                 return 0;
  763         switch (lbn & 0x3) {
  764         case 0:
  765                 return (0);
  766         case 1:
  767                 break;
  768         case 2:
  769                 return (2);
  770         case 3:
  771                 return (1);
  772         default:
  773                 break;
  774         }
  775         return (-1);
  776 }
  777 
  778 static inline ufs_lbn_t
  779 lbn_offset(struct fs *fs, int level)
  780 {
  781         ufs_lbn_t res;
  782 
  783         for (res = 1; level > 0; level--)
  784                 res *= NINDIR(fs);
  785         return (res);
  786 }
  787 
  788 /*
  789  * Number of inodes in a secondary storage block/fragment.
  790  */
  791 #define INOPB(fs)       ((fs)->fs_inopb)
  792 #define INOPF(fs)       ((fs)->fs_inopb >> (fs)->fs_fragshift)
  793 
  794 /*
  795  * Softdep journal record format.
  796  */
  797 
  798 #define JOP_ADDREF      1       /* Add a reference to an inode. */
  799 #define JOP_REMREF      2       /* Remove a reference from an inode. */
  800 #define JOP_NEWBLK      3       /* Allocate a block. */
  801 #define JOP_FREEBLK     4       /* Free a block or a tree of blocks. */
  802 #define JOP_MVREF       5       /* Move a reference from one off to another. */
  803 #define JOP_TRUNC       6       /* Partial truncation record. */
  804 #define JOP_SYNC        7       /* fsync() complete record. */
  805 
  806 #define JREC_SIZE       32      /* Record and segment header size. */
  807 
  808 #define SUJ_MIN         (4 * 1024 * 1024)       /* Minimum journal size */
  809 #define SUJ_FILE        ".sujournal"            /* Journal file name */
  810 
  811 /*
  812  * Size of the segment record header.  There is at most one for each disk
  813  * block in the journal.  The segment header is followed by an array of
  814  * records.  fsck depends on the first element in each record being 'op'
  815  * and the second being 'ino'.  Segments may span multiple disk blocks but
  816  * the header is present on each.
  817  */
  818 struct jsegrec {
  819         uint64_t        jsr_seq;        /* Our sequence number */
  820         uint64_t        jsr_oldest;     /* Oldest valid sequence number */
  821         uint16_t        jsr_cnt;        /* Count of valid records */
  822         uint16_t        jsr_blocks;     /* Count of device bsize blocks. */
  823         uint32_t        jsr_crc;        /* 32bit crc of the valid space */
  824         ufs_time_t      jsr_time;       /* timestamp for mount instance */
  825 };
  826 
  827 /*
  828  * Reference record.  Records a single link count modification.
  829  */
  830 struct jrefrec {
  831         uint32_t        jr_op;
  832         uint32_t        jr_ino;
  833         uint32_t        jr_parent;
  834         uint16_t        jr_nlink;
  835         uint16_t        jr_mode;
  836         int64_t         jr_diroff;
  837         uint64_t        jr_unused;
  838 };
  839 
  840 /*
  841  * Move record.  Records a reference moving within a directory block.  The
  842  * nlink is unchanged but we must search both locations.
  843  */
  844 struct jmvrec {
  845         uint32_t        jm_op;
  846         uint32_t        jm_ino;
  847         uint32_t        jm_parent;
  848         uint16_t        jm_unused;
  849         int64_t         jm_oldoff;
  850         int64_t         jm_newoff;
  851 };
  852 
  853 /*
  854  * Block record.  A set of frags or tree of blocks starting at an indirect are
  855  * freed or a set of frags are allocated.
  856  */
  857 struct jblkrec {
  858         uint32_t        jb_op;
  859         uint32_t        jb_ino;
  860         ufs2_daddr_t    jb_blkno;
  861         ufs_lbn_t       jb_lbn;
  862         uint16_t        jb_frags;
  863         uint16_t        jb_oldfrags;
  864         uint32_t        jb_unused;
  865 };
  866 
  867 /*
  868  * Truncation record.  Records a partial truncation so that it may be
  869  * completed at check time.  Also used for sync records.
  870  */
  871 struct jtrncrec {
  872         uint32_t        jt_op;
  873         uint32_t        jt_ino;
  874         int64_t         jt_size;
  875         uint32_t        jt_extsize;
  876         uint32_t        jt_pad[3];
  877 };
  878 
  879 union jrec {
  880         struct jsegrec  rec_jsegrec;
  881         struct jrefrec  rec_jrefrec;
  882         struct jmvrec   rec_jmvrec;
  883         struct jblkrec  rec_jblkrec;
  884         struct jtrncrec rec_jtrncrec;
  885 };
  886 
  887 #ifdef CTASSERT
  888 CTASSERT(sizeof(struct jsegrec) == JREC_SIZE);
  889 CTASSERT(sizeof(struct jrefrec) == JREC_SIZE);
  890 CTASSERT(sizeof(struct jmvrec) == JREC_SIZE);
  891 CTASSERT(sizeof(struct jblkrec) == JREC_SIZE);
  892 CTASSERT(sizeof(struct jtrncrec) == JREC_SIZE);
  893 CTASSERT(sizeof(union jrec) == JREC_SIZE);
  894 #endif
  895 
  896 extern int inside[], around[];
  897 extern u_char *fragtbl[];
  898 
  899 /*
  900  * IOCTLs used for filesystem write suspension.
  901  */
  902 #define UFSSUSPEND      _IOW('U', 1, fsid_t)
  903 #define UFSRESUME       _IO('U', 2)
  904 
  905 #endif

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