sys/pcfs/pcfs_vfsops.c

/*
 *  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
 *
 *      $Id$
 */

#include "param.h"
#include "systm.h"
#include "namei.h"
#include "proc.h"
#include "kernel.h"
#include "vnode.h"
#include "specdev.h"    /* defines v_rdev       */
#include "mount.h"
#include "buf.h"
#include "file.h"
#include "malloc.h"

#include "bpb.h"
#include "bootsect.h"
#include "direntry.h"
#include "denode.h"
#include "pcfsmount.h"
#include "fat.h"

int pcfsdoforce = 0;    /* 1 = force unmount */

/*
 *  mp -
 *  path - addr in user space of mount point (ie /usr or whatever)
 *  data - addr in user space of mount params including the
 *         name of the block special file to treat as a filesystem.
 *  ndp  -
 *  p    -
 */
int
pcfs_mount(mp, path, data, ndp, p)
        struct mount *mp;
        char *path;
        caddr_t data;
        struct nameidata *ndp;
        struct proc *p;
{
        struct vnode *devvp;    /* vnode for blk device to mount        */
        struct pcfs_args args;  /* will hold data from mount request    */
        struct pcfsmount *pmp;  /* pcfs specific mount control block    */
        int error;
        u_int size;

/*
 *  Copy in the args for the mount request.
 */
        if (error = copyin(data, (caddr_t)&args, sizeof(struct pcfs_args)))
                return error;

/*
 *  Check to see if they want it to be an exportable
 *  filesystem via nfs.  And, if they do, should it
 *  be read only, and what uid is root to be mapped
 *  to.
 */
        if ((args.exflags & MNT_EXPORTED)  ||  (mp->mnt_flag & MNT_EXPORTED)) {
                if (args.exflags & MNT_EXPORTED)
                        mp->mnt_flag |= MNT_EXPORTED;
                else
                        mp->mnt_flag &= ~MNT_EXPORTED;
                if (args.exflags & MNT_EXRDONLY)
                        mp->mnt_flag |= MNT_EXRDONLY;
                else
                        mp->mnt_flag &= ~MNT_EXRDONLY;
                mp->mnt_exroot = args.exroot;
        }

/*
 *  If they just want to update then be sure we can
 *  do what is asked.  Can't change a filesystem from
 *  read/write to read only.  Why?
 *  And if they've supplied a new device file name then we
 *  continue, otherwise return.
 */
        if (mp->mnt_flag & MNT_UPDATE) {
                pmp = (struct pcfsmount *)mp->mnt_data;
                if (pmp->pm_ronly  &&  (mp->mnt_flag & MNT_RDONLY) == 0)
                        pmp->pm_ronly = 0;
                if (args.fspec == 0)
                        return 0;
        }

/*
 *  Now, lookup the name of the block device this
 *  mount or name update request is to apply to.
 */
        ndp->ni_nameiop = LOOKUP | FOLLOW;
        ndp->ni_segflg  = UIO_USERSPACE;
        ndp->ni_dirp    = args.fspec;
        if (error = namei(ndp, p))
                return error;

/*
 *  Be sure they've given us a block device to treat
 *  as a filesystem.  And, that its major number is
 *  within the bdevsw table.
 */
        devvp = ndp->ni_vp;
        if (devvp->v_type != VBLK) {
                vrele(devvp);           /* namei() acquires this?       */
                return ENOTBLK;
        }
        if (major(devvp->v_rdev) >= nblkdev) {
                vrele(devvp);
                return ENXIO;
        }

/*
 *  If this is an update, then make sure the vnode
 *  for the block special device is the same as the
 *  one our filesystem is in.
 */
        if (mp->mnt_flag & MNT_UPDATE) {
                if (devvp != pmp->pm_devvp)
                        error = EINVAL;
                else
                        vrele(devvp);
        } else {

/*
 *  Well, it's not an update, it's a real mount request.
 *  Time to get dirty.
 */
                error = mountpcfs(devvp, mp, p);
        }
        if (error) {
                vrele(devvp);
                return error;
        }

/*
 *  Copy in the name of the directory the filesystem
 *  is to be mounted on.
 *  Then copy in the name of the block special file
 *  representing the filesystem being mounted.
 *  And we clear the remainder of the character strings
 *  to be tidy.
 *  Then, we try to fill in the filesystem stats structure
 *  as best we can with whatever applies from a dos file
 *  system.
 */
        pmp = (struct pcfsmount *)mp->mnt_data;
        copyinstr(path, (caddr_t)mp->mnt_stat.f_mntonname,
                sizeof(mp->mnt_stat.f_mntonname)-1, &size);
        bzero(mp->mnt_stat.f_mntonname + size,
                sizeof(mp->mnt_stat.f_mntonname) - size);
        copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN-1, &size);
        bzero(mp->mnt_stat.f_mntfromname + size,
                MNAMELEN - size);
        (void)pcfs_statfs(mp, &mp->mnt_stat, p);
#if defined(PCFSDEBUG)
printf("pcfs_mount(): mp %x, pmp %x, inusemap %x\n", mp, pmp, pmp->pm_inusemap);
#endif /* defined(PCFSDEBUG) */
        return 0;
}

int
mountpcfs(devvp, mp, p)
        struct vnode *devvp;
        struct mount *mp;
        struct proc *p;
{
        int i;
        int bpc;
        int bit;
        int error = 0;
        int needclose;
        int ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
        dev_t dev = devvp->v_rdev;
        union bootsector *bsp;
        struct pcfsmount *pmp = NULL;
        struct buf *bp0 = NULL;
        struct byte_bpb33 *b33;
        struct byte_bpb50 *b50;

/*
 *  Multiple mounts of the same block special file
 *  aren't allowed.  Make sure no one else has the
 *  special file open.  And flush any old buffers
 *  from this filesystem.  Presumably this prevents
 *  us from running into buffers that are the wrong
 *  blocksize.
 *  NOTE: mountedon() is a part of the ufs filesystem.
 *  If the ufs filesystem is not gen'ed into the system
 *  we will get an unresolved reference.
 */
        if (error = mountedon(devvp)) {
                return error;
        }
        if (vcount(devvp) > 1)
                return EBUSY;
        vinvalbuf(devvp, 1);

/*
 *  Now open the block special file.
 */
        if (error = VOP_OPEN(devvp, ronly ? FREAD : FREAD|FWRITE, NOCRED, p))
                return error;
        needclose = 1;
#if defined(HDSUPPORT)
/*
 *  Put this in when we support reading dos filesystems
 *  from partitioned harddisks.
 */
        if (VOP_IOCTL(devvp, DIOCGPART, &pcfspart, FREAD, NOCRED, p) == 0) {
        }
#endif /* defined(HDSUPPORT) */

/*
 *  Read the boot sector of the filesystem, and then
 *  check the boot signature.  If not a dos boot sector
 *  then error out.  We could also add some checking on
 *  the bsOemName field.  So far I've seen the following
 *  values:
 *    "IBM  3.3"
 *    "MSDOS3.3"
 *    "MSDOS5.0"
 */
        if (error = bread(devvp, 0, 512, NOCRED, &bp0))
                goto error_exit;
        bp0->b_flags |= B_AGE;
        bsp = (union bootsector *)bp0->b_un.b_addr;
        b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
        b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
        if (bsp->bs50.bsBootSectSig != BOOTSIG) {
                error = EINVAL;
                goto error_exit;
        }

        pmp = malloc(sizeof *pmp, M_PCFSMNT, M_WAITOK);
        pmp->pm_inusemap = NULL;
        pmp->pm_mountp = mp;

/*
 *  Compute several useful quantities from the bpb in
 *  the bootsector.  Copy in the dos 5 variant of the
 *  bpb then fix up the fields that are different between
 *  dos 5 and dos 3.3.
 */
        pmp->pm_BytesPerSec  = getushort(b50->bpbBytesPerSec);
        pmp->pm_SectPerClust = b50->bpbSecPerClust;
        pmp->pm_ResSectors   = getushort(b50->bpbResSectors);
        pmp->pm_FATs         = b50->bpbFATs;
        pmp->pm_RootDirEnts  = getushort(b50->bpbRootDirEnts);
        pmp->pm_Sectors      = getushort(b50->bpbSectors);
        pmp->pm_Media        = b50->bpbMedia;
        pmp->pm_FATsecs      = getushort(b50->bpbFATsecs);
        pmp->pm_SecPerTrack  = getushort(b50->bpbSecPerTrack);
        pmp->pm_Heads        = getushort(b50->bpbHeads);
        if (pmp->pm_Sectors == 0) {
                pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
                pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
        } else {
                pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
                pmp->pm_HugeSectors = pmp->pm_Sectors;
        }
        pmp->pm_fatblk = pmp->pm_ResSectors;
        pmp->pm_rootdirblk = pmp->pm_fatblk +
                (pmp->pm_FATs * pmp->pm_FATsecs);
        pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry))
                                        /
                                pmp->pm_BytesPerSec; /* in sectors */
        pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
        pmp->pm_nmbrofclusters = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
                pmp->pm_SectPerClust;
        pmp->pm_maxcluster = pmp->pm_nmbrofclusters + 1;
        pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec;
        if (FAT12(pmp))
                /* This will usually be a floppy disk.
                 * This size makes sure that one fat entry will not be split
                 * across multiple blocks. */
                pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
        else
                /* This will usually be a hard disk.
                 * Reading or writing one block should be quite fast. */
                pmp->pm_fatblocksize = MAXBSIZE;
        pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec;

        if ((pmp->pm_rootdirsize % pmp->pm_SectPerClust) != 0)
                printf("mountpcfs(): root directory is not a multiple of the clustersize in length\n");

/*
 *  Compute mask and shift value for isolating cluster relative
 *  byte offsets and cluster numbers from a file offset.
 */
        bpc = pmp->pm_SectPerClust * pmp->pm_BytesPerSec;
        pmp->pm_bpcluster = bpc;
        pmp->pm_depclust  = bpc/sizeof(struct direntry);
        pmp->pm_crbomask = bpc - 1;
        if (bpc == 0) {
                error = EINVAL;
                goto error_exit;
        }
        bit = 1;
        for (i = 0; i < 32; i++) {
                if (bit & bpc) {
                        if (bit ^ bpc) {
                                error = EINVAL;
                                goto error_exit;
                        }
                        pmp->pm_cnshift = i;
                        break;
                }
                bit <<= 1;
        }

        pmp->pm_brbomask = 0x01ff;      /* 512 byte blocks only (so far) */
        pmp->pm_bnshift = 9;            /* shift right 9 bits to get bn */

/*
 *  Release the bootsector buffer.
 */
        brelse(bp0);
        bp0 = NULL;

/*
 *  Allocate memory for the bitmap of allocated clusters,
 *  and then fill it in.
 */
        pmp->pm_inusemap = malloc((pmp->pm_maxcluster >> 3) + 1,
                M_PCFSFAT, M_WAITOK);

/*
 *  fillinusemap() needs pm_devvp.
 */
        pmp->pm_dev = dev;
        pmp->pm_devvp = devvp;

/*
 *  Have the inuse map filled in.
 */
        error = fillinusemap(pmp);
        if (error)
                goto error_exit;

/*
 *  If they want fat updates to be synchronous then let
 *  them suffer the performance degradation in exchange
 *  for the on disk copy of the fat being correct just
 *  about all the time.  I suppose this would be a good
 *  thing to turn on if the kernel is still flakey.
 */
        pmp->pm_waitonfat = mp->mnt_flag & MNT_SYNCHRONOUS;

/*
 *  Finish up.
 */
        pmp->pm_ronly = ronly;
        if (ronly == 0)
                pmp->pm_fmod = 1;
        mp->mnt_data = (qaddr_t)pmp;
        mp->mnt_stat.f_fsid.val[0] = (long)dev;
        mp->mnt_stat.f_fsid.val[1] = MOUNT_MSDOS;
        mp->mnt_flag |= MNT_LOCAL;
#if defined(QUOTA)
/*
 *  If we ever do quotas for DOS filesystems this would
 *  be a place to fill in the info in the pcfsmount
 *  structure.
 *  You dolt, quotas on dos filesystems make no sense
 *  because files have no owners on dos filesystems.
 *  of course there is some empty space in the directory
 *  entry where we could put uid's and gid's.
 */
#endif /* defined(QUOTA) */
        devvp->v_specflags |= SI_MOUNTEDON;

        return 0;

error_exit:;
        if (bp0)
                brelse(bp0);
        if (needclose)
                (void)VOP_CLOSE(devvp, ronly ? FREAD : FREAD|FWRITE,
                        NOCRED, p);
        if (pmp) {
                if (pmp->pm_inusemap)
                        free((caddr_t)pmp->pm_inusemap, M_PCFSFAT);
                free((caddr_t)pmp, M_PCFSMNT);
                mp->mnt_data = (qaddr_t)0;
        }
        return error;
}

int
pcfs_start(mp, flags, p)
        struct mount *mp;
        int flags;
        struct proc *p;
{
        return 0;
}

/*
 *  Unmount the filesystem described by mp.
 */
int
pcfs_unmount(mp, mntflags, p)
        struct mount *mp;
        int mntflags;
        struct proc *p;
{
        int flags = 0;
        int error;
        struct pcfsmount *pmp = (struct pcfsmount *)mp->mnt_data;
        struct vnode *vp = pmp->pm_devvp;

        if (mntflags & MNT_FORCE) {
                if (!pcfsdoforce)
                        return EINVAL;
                flags |= FORCECLOSE;
        }
        mntflushbuf(mp, 0);
        if (mntinvalbuf(mp))
                return EBUSY;
#if defined(QUOTA)
#endif /* defined(QUOTA) */
        if (error = vflush(mp, NULLVP, flags))
                return error;
        pmp->pm_devvp->v_specflags &= ~SI_MOUNTEDON;
#if defined(PCFSDEBUG)
printf("pcfs_umount(): just before calling VOP_CLOSE()\n");
printf("flag %08x, usecount %d, writecount %d, holdcnt %d\n",
        vp->v_flag, vp->v_usecount, vp->v_writecount, vp->v_holdcnt);
printf("lastr %d, id %d, mount %08x, op %08x\n",
        vp->v_lastr, vp->v_id, vp->v_mount, vp->v_op);
printf("freef %08x, freeb %08x, mountf %08x, mountb %08x\n",
        vp->v_freef, vp->v_freeb, vp->v_mountf, vp->v_mountb);
printf("cleanblkhd %08x, dirtyblkhd %08x, numoutput %d, type %d\n",
        vp->v_cleanblkhd, vp->v_dirtyblkhd, vp->v_numoutput, vp->v_type);
printf("union %08x, tag %d, data[0] %08x, data[1] %08x\n",
        vp->v_socket, vp->v_tag, vp->v_data[0], vp->v_data[1]);
#endif /* defined(PCFSDEBUG) */
        error = VOP_CLOSE(pmp->pm_devvp, pmp->pm_ronly ? FREAD : FREAD|FWRITE,
                NOCRED, p);
        vrele(pmp->pm_devvp);
        free((caddr_t)pmp->pm_inusemap, M_PCFSFAT);
        free((caddr_t)pmp, M_PCFSMNT);
        mp->mnt_data = (qaddr_t)0;
        mp->mnt_flag &= ~MNT_LOCAL;
        return error;
}

int
pcfs_root(mp, vpp)
        struct mount *mp;
        struct vnode **vpp;
{
        struct denode *ndep;
        struct pcfsmount *pmp = (struct pcfsmount *)(mp->mnt_data);
        int error;

        error = deget(pmp, PCFSROOT, PCFSROOT_OFS, NULL, &ndep);
#if defined(PCFSDEBUG)
printf("pcfs_root(); mp %08x, pmp %08x, ndep %08x, vp %08x\n",
 mp, pmp, ndep, DETOV(ndep));
#endif /* defined(PCFSDEBUG) */
        if (error == 0)
                *vpp = DETOV(ndep);
        return error;
}

int
pcfs_quotactl(mp, cmds, uid, arg, p)
        struct mount *mp;
        int cmds;
        uid_t uid;
        caddr_t arg;
        struct proc *p;
{
#if defined(QUOTA)
#else
        return EOPNOTSUPP;
#endif /* defined(QUOTA) */
}

int
pcfs_statfs(mp, sbp, p)
        struct mount *mp;
        struct statfs *sbp;
        struct proc *p;
{
        struct pcfsmount *pmp = (struct pcfsmount *)mp->mnt_data;

/*
 *  Fill in the stat block.
 */
        sbp->f_type   = MOUNT_MSDOS;
        sbp->f_fsize  = pmp->pm_bpcluster;
        sbp->f_bsize  = pmp->pm_bpcluster;
        sbp->f_blocks = pmp->pm_nmbrofclusters;
        sbp->f_bfree  = pmp->pm_freeclustercount;
        sbp->f_bavail = pmp->pm_freeclustercount;
        sbp->f_files  = pmp->pm_RootDirEnts;
        sbp->f_ffree  = 0;              /* what to put in here? */

/*
 *  Copy the mounted on and mounted from names into
 *  the passed in stat block, if it is not the one
 *  in the mount structure.
 */
        if (sbp != &mp->mnt_stat) {
                bcopy((caddr_t)mp->mnt_stat.f_mntonname,
                        (caddr_t)&sbp->f_mntonname[0], MNAMELEN);
                bcopy((caddr_t)mp->mnt_stat.f_mntfromname,
                        (caddr_t)&sbp->f_mntfromname[0], MNAMELEN);
        }
        return 0;
}

int
pcfs_sync(mp, waitfor)
        struct mount *mp;
        int waitfor;
{
        struct vnode *vp;
        struct denode *dep;
        struct pcfsmount *pmp;
        int error;
        int allerror = 0;

        pmp = (struct pcfsmount *)mp->mnt_data;

/*
 *  If we ever switch to not updating all of the fats
 *  all the time, this would be the place to update them
 *  from the first one.
 */
        if (pmp->pm_fmod) {
                if (pmp->pm_ronly) {
                        printf("pcfs_sync(): writing to readonly filesystem\n");
                        return EINVAL;
                } else {
                        /* update fats here */
                }
        }

/*
 *  Go thru in memory denodes and write them out along
 *  with unwritten file blocks.
 */
loop:
        for (vp = mp->mnt_mounth; vp; vp = vp->v_mountf) {
                if (vp->v_mount != mp)  /* not ours anymore     */
                        goto loop;
                if (VOP_ISLOCKED(vp))   /* file is busy         */
                        continue;
                dep = VTODE(vp);
                if ((dep->de_flag & DEUPD) == 0  &&  vp->v_dirtyblkhd == NULL)
                        continue;
                if (vget(vp))           /* not there anymore?   */
                        goto loop;
                if (vp->v_dirtyblkhd)   /* flush dirty file blocks */
                        vflushbuf(vp, 0);
                if ((dep->de_flag & DEUPD)  &&
                    (error = deupdat(dep, &time, 0)))
                        allerror = error;
                vput(vp);               /* done with this one   */
        }

/*
 *  Flush filesystem control info.
 */
        vflushbuf(pmp->pm_devvp, waitfor == MNT_WAIT ? B_SYNC : 0);
        return allerror;
}

int
pcfs_fhtovp (mp, fhp, vpp)
        struct mount *mp;
        struct fid *fhp;
        struct vnode **vpp;
{
        struct pcfsmount *pmp = (struct pcfsmount *)mp->mnt_data;
        struct defid *defhp = (struct defid *)fhp;
        struct denode *dep;
        int error;

        error = deget (pmp, defhp->defid_dirclust, defhp->defid_dirofs,
                        NULL, &dep);
        if (error)
                return (error);
        *vpp = DETOV (dep);
        return (0);
}


int
pcfs_vptofh (vp, fhp)
        struct vnode *vp;
        struct fid *fhp;
{
        struct denode *dep = VTODE(vp);
        struct defid *defhp = (struct defid *)fhp;

        defhp->defid_len = sizeof(struct defid);
        defhp->defid_dirclust = dep->de_dirclust;
        defhp->defid_dirofs = dep->de_diroffset;
/*      defhp->defid_gen = ip->i_gen; */
        return (0);
}

struct vfsops pcfs_vfsops = {
        pcfs_mount,
        pcfs_start,
        pcfs_unmount,
        pcfs_root,
        pcfs_quotactl,
        pcfs_statfs,
        pcfs_sync,
        pcfs_fhtovp,
        pcfs_vptofh,
        pcfs_init
};