sys/fs/msdosfs/msdosfsmount.h

/*
 * Written by Paul Popelka (paulp@uts.amdahl.com)
 *
 * You can do anything you want with this software, just don't say you wrote
 * it, and don't remove this notice.
 *
 * This software is provided "as is".
 *
 * The author supplies this software to be publicly redistributed on the
 * understanding that the author is not responsible for the correct
 * functioning of this software in any circumstances and is not liable for
 * any damages caused by this software.
 *
 * October 1992
 *
 *      from NetBSD:    msdosfsmount.h,v 1.1 1993/08/13 11:35:41 cgd Exp
 *      $Id$
 */

/*
 * Layout of the mount control block for a msdos file system.
 */
struct msdosfsmount {
        struct mount *pm_mountp;/* vfs mount struct for this fs */
        dev_t pm_dev;           /* block special device mounted */
        struct vnode *pm_devvp; /* vnode for block device mntd */
        struct bpb50 pm_bpb;    /* BIOS parameter blk for this fs */
        u_long pm_fatblk;       /* block # of first FAT */
        u_long pm_rootdirblk;   /* block # of root directory */
        u_long pm_rootdirsize;  /* size in blocks (not clusters) */
        u_long pm_firstcluster; /* block number of first cluster */
        u_long pm_nmbrofclusters;       /* # of clusters in filesystem */
        u_long pm_maxcluster;   /* maximum cluster number */
        u_long pm_freeclustercount;     /* number of free clusters */
        u_long pm_lookhere;     /* start free cluster search here */
        u_long pm_bnshift;      /* shift file offset right this amount to get a block number */
        u_long pm_brbomask;     /* and a file offset with this mask to get block rel offset */
        u_long pm_cnshift;      /* shift file offset right this amount to get a cluster number */
        u_long pm_crbomask;     /* and a file offset with this mask to get cluster rel offset */
        u_long pm_bpcluster;    /* bytes per cluster */
        u_long pm_depclust;     /* directory entries per cluster */
        u_long pm_fmod;         /* ~0 if fs is modified, this can rollover to 0 */
        u_long pm_fatblocksize; /* size of fat blocks in bytes */
        u_long pm_fatblocksec;  /* size of fat blocks in sectors */
        u_long pm_fatsize;      /* size of fat in bytes */
        u_char *pm_inusemap;    /* ptr to bitmap of in-use clusters */
        char pm_ronly;          /* read only if non-zero */
        char pm_waitonfat;      /* wait for writes of the fat to complt, when 0 use bdwrite, else use bwrite */
};

/*
 * How to compute pm_cnshift and pm_crbomask.
 *
 * pm_crbomask = (pm_SectPerClust * pm_BytesPerSect) - 1
 * if (bytesperclust == * 0)
 *      return EBADBLKSZ;
 * bit = 1;
 * for (i = 0; i < 32; i++) {
 *      if (bit & bytesperclust) {
 *              if (bit ^ bytesperclust)
 *                      return EBADBLKSZ;
 *              pm_cnshift = * i;
 *              break;
 *      }
 *      bit <<= 1;
 * }
 */

/*
 * Shorthand for fields in the bpb contained in the msdosfsmount structure.
 */
#define pm_BytesPerSec  pm_bpb.bpbBytesPerSec
#define pm_SectPerClust pm_bpb.bpbSecPerClust
#define pm_ResSectors   pm_bpb.bpbResSectors
#define pm_FATs         pm_bpb.bpbFATs
#define pm_RootDirEnts  pm_bpb.bpbRootDirEnts
#define pm_Sectors      pm_bpb.bpbSectors
#define pm_Media        pm_bpb.bpbMedia
#define pm_FATsecs      pm_bpb.bpbFATsecs
#define pm_SecPerTrack  pm_bpb.bpbSecPerTrack
#define pm_Heads        pm_bpb.bpbHeads
#define pm_HiddenSects  pm_bpb.bpbHiddenSecs
#define pm_HugeSectors  pm_bpb.bpbHugeSectors

/*
 * Map a cluster number into a filesystem relative block number.
 */
#define cntobn(pmp, cn) \
        ((((cn)-CLUST_FIRST) * (pmp)->pm_SectPerClust) + (pmp)->pm_firstcluster)

/*
 * Map a filesystem relative block number back into a cluster number.
 */
#define bntocn(pmp, bn) \
        ((((bn) - pmp->pm_firstcluster)/ (pmp)->pm_SectPerClust) + CLUST_FIRST)

/*
 * Calculate block number for directory entry in root dir, offset dirofs
 */
#define roottobn(pmp, dirofs) \
        (((dirofs) / (pmp)->pm_depclust) * (pmp)->pm_SectPerClust \
        + (pmp)->pm_rootdirblk)

/*
 * Calculate block number for directory entry at cluster dirclu, offset
 * dirofs
 */
#define detobn(pmp, dirclu, dirofs) \
        ((dirclu) == MSDOSFSROOT \
         ? roottobn((pmp), (dirofs)) \
         : cntobn((pmp), (dirclu)))

/*
 * Convert pointer to buffer -> pointer to direntry
 */
#define bptoep(pmp, bp, dirofs) \
        ((struct direntry *)((bp)->b_un.b_addr) \
         + (dirofs) % (pmp)->pm_depclust)


/*
 * Prototypes for MSDOSFS virtual filesystem operations
 */
int msdosfs_mount __P((struct mount * mp, char *path, caddr_t data, struct nameidata * ndp, struct proc * p));
int msdosfs_start __P((struct mount * mp, int flags, struct proc * p));
int msdosfs_unmount __P((struct mount * mp, int mntflags, struct proc * p));
int msdosfs_root __P((struct mount * mp, struct vnode ** vpp));
int msdosfs_quotactl __P((struct mount * mp, int cmds, int uid  /* should be uid_t */, caddr_t arg, struct proc * p));
int msdosfs_statfs __P((struct mount * mp, struct statfs * sbp, struct proc * p));
int msdosfs_sync __P((struct mount * mp, int waitfor));
int msdosfs_fhtovp __P((struct mount * mp, struct fid * fhp, struct vnode ** vpp));
int msdosfs_vptofh __P((struct vnode * vp, struct fid * fhp));
int msdosfs_init __P(());