Source to pcfs/pcfs_vnops.c


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/*
 *  Written by Paul Popelka ([email protected])
 *
 *  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
 *
 *	pcfs_vnops.c,v 1.3.2.1 1993/08/05 02:37:23 cgd Exp
 */

#include "param.h"
#include "systm.h"
#include "namei.h"
#include "resourcevar.h"	/* defines plimit structure in proc struct */
#include "kernel.h"
#include "file.h"		/* define FWRITE ... */
#include "stat.h"
#include "buf.h"
#include "proc.h"
#include "mount.h"
#include "vnode.h"
#include "specdev.h"		/* defines plimit structure in the proc struct */
#include "malloc.h"

#include "dir.h"		/* defines dirent structure		*/

#include "bpb.h"
#include "direntry.h"
#include "denode.h"
#include "pcfsmount.h"
#include "fat.h"
/*
 *  Some general notes:
 *
 *  In the ufs filesystem the inodes, superblocks, and indirect
 *  blocks are read/written using the vnode for the filesystem.
 *  Blocks that represent the contents of a file are read/written
 *  using the vnode for the file (including directories when
 *  they are read/written as files).
 *  This presents problems for the dos filesystem because data
 *  that should be in an inode (if dos had them) resides in the
 *  directory itself.  Since we must update directory entries
 *  without the benefit of having the vnode for the directory
 *  we must use the vnode for the filesystem.  This means that
 *  when a directory is actually read/written (via read, write,
 *  or readdir, or seek) we must use the vnode for the filesystem
 *  instead of the vnode for the directory as would happen in ufs.
 *  This is to insure we retreive the correct block from the
 *  buffer cache since the hash value is based upon the vnode
 *  address and the desired block number.
 */

/*
 *  Create a regular file.
 *  On entry the directory to contain the file being
 *  created is locked.  We must release before we
 *  return.
 *  We must also free the pathname buffer pointed at
 *  by ndp->ni_pnbuf, always on error, or only if the
 *  SAVESTART bit in ni_nameiop is clear on success.
 */
int
pcfs_create(ndp, vap, p)
	struct nameidata *ndp;
	struct vattr *vap;
	struct proc *p;
{
	struct denode ndirent;
	struct direntry *ndirp = &ndirent.de_de;
	struct denode *dep;
	struct denode *pdep = VTODE(ndp->ni_dvp);
	int error;
#if defined(PCFSDEBUG)
printf("pcfs_create(ndp %08x, vap %08x, p %08x\n", ndp, vap, p);
#endif /* defined(PCFSDEBUG) */

/*
 *  Create a directory entry for the file, then call
 *  createde() to have it installed.
 *  NOTE: DOS files are always executable.  We use the
 *  absence of the owner write bit to make the file readonly.
 */
	bzero(&ndirent, sizeof(ndirent));
	unix2dostime(&time, (union dosdate *)&ndirp->deDate,
		(union dostime *)&ndirp->deTime);
	unix2dosfn((u_char *)ndp->ni_ptr, ndirp->deName, ndp->ni_namelen);
	ndirp->deAttributes = (vap->va_mode & VWRITE) ? 0 : ATTR_READONLY;
	ndirp->deStartCluster = 0;
	ndirp->deFileSize = 0;
	ndirent.de_pmp = pdep->de_pmp;
	ndirent.de_dev = pdep->de_dev;
	ndirent.de_devvp = pdep->de_devvp;
	if ((error = createde(&ndirent, ndp, &dep)) == 0) {
		ndp->ni_vp = DETOV(dep);
		if ((ndp->ni_nameiop & SAVESTART) == 0)
			free(ndp->ni_pnbuf, M_NAMEI);
	} else {
		free(ndp->ni_pnbuf, M_NAMEI);
	}
	deput(pdep);		/* release parent dir	*/
	return error;
}

int
pcfs_mknod(ndp, vap, cred, p)
	struct nameidata *ndp;
	struct vattr *vap;
	struct ucred *cred;
	struct proc *p;
{
	int error;

	switch (vap->va_type) {
	case VDIR:
		error = pcfs_mkdir(ndp, vap, p);
		break;

/*
 *  pcfs_create() sets ndp->ni_vp.
 */
	case VREG:
		error = pcfs_create(ndp, vap, p);
		break;

	default:
		error = EINVAL;
		break;
	}
	return error;
}

int
pcfs_open(vp, mode, cred, p)
	struct vnode *vp;
	int mode;
	struct ucred *cred;
	struct proc *p;
{
	return 0;
}

int
pcfs_close(vp, fflag, cred, p)
	struct vnode *vp;
	int fflag;
	struct ucred *cred;
	struct proc *p;
{
	struct denode *dep = VTODE(vp);

	if (vp->v_usecount > 1  &&  !(dep->de_flag & DELOCKED))
		DETIMES(dep, &time);
	return 0;
}

int
pcfs_access(vp, mode, cred, p)
	struct vnode *vp;
	int mode;
	struct ucred *cred;
	struct proc *p;
{
	int dosmode;
	struct denode *dep = VTODE(vp);

/*
 *  Root gets to do anything.  Even execute a file
 *  without the x-bit on?  But, for dos filesystems
 *  every file is executable.  I may regret this.
 */
	if (cred->cr_uid == 0)
		return 0;

/*
 *  mode is filled with a combination of VREAD, VWRITE,
 *  and/or VEXEC bits turned on.  In an octal number these
 *  are the Y in 0Y00.
 *
 *  Since the dos filesystem doesn't have the concept of
 *  file ownership we just give everybody read and execute
 *  access and write access if the readonly bit is off.
 */
	dosmode = VEXEC | VREAD |
		((dep->de_Attributes & ATTR_READONLY) ? 0 : VWRITE);
	return ((dosmode & mode) != 0) ? 0 : EACCES;
}

int
pcfs_getattr(vp, vap, cred, p)
	struct vnode *vp;
	struct vattr *vap;
	struct ucred *cred;
	struct proc *p;
{
	u_int cn;
	struct denode *dep = VTODE(vp);

	DETIMES(dep, &time);
	vap->va_fsid = dep->de_dev;
	/* The following computation of the fileid must be the
	 * same as that used in pcfs_readdir() to compute d_fileno.
	 * If not, pwd doesn't work. */
	if (dep->de_Attributes & ATTR_DIRECTORY) {
		if ((cn = dep->de_StartCluster) == PCFSROOT)
			cn = 1;
	} else {
		if ((cn = dep->de_dirclust) == PCFSROOT)
			cn = 1;
		cn = (cn << 16) | (dep->de_diroffset & 0xffff);
	}
	vap->va_fileid = cn;
	vap->va_mode = (dep->de_Attributes & ATTR_READONLY) ? 0555 : 0777;
	if (dep->de_Attributes & ATTR_DIRECTORY)
		vap->va_mode |= S_IFDIR;
	vap->va_nlink = 1;
	vap->va_gid = 0;
	vap->va_uid = 0;
	vap->va_rdev = 0;
	vap->va_size = dep->de_FileSize;
	vap->va_size_rsv = 0;
	dos2unixtime((union dosdate *)&dep->de_Date,
		(union dostime *)&dep->de_Time, &vap->va_atime);
	vap->va_atime.tv_usec = 0;
	vap->va_mtime.tv_sec = vap->va_atime.tv_sec;
	vap->va_mtime.tv_usec = 0;
	vap->va_ctime.tv_sec = vap->va_atime.tv_sec;
	vap->va_ctime.tv_usec = 0;
	vap->va_flags = dep->de_flag;
	vap->va_gen = 0;
	vap->va_blocksize = dep->de_pmp->pm_bpcluster;
	vap->va_bytes = (dep->de_FileSize + dep->de_pmp->pm_crbomask) &
		~(dep->de_pmp->pm_crbomask);
	vap->va_bytes_rsv = 0;
	vap->va_type = vp->v_type;
	return 0;
}

int
pcfs_setattr(vp, vap, cred, p)
	struct vnode *vp;
	struct vattr *vap;
	struct ucred *cred;
	struct proc *p;
{
	int error = 0;
	struct denode *dep = VTODE(vp);

#if defined(PCFSDEBUG)
printf("pcfs_setattr(): vp %08x, vap %08x, cred %08x, p %08x\n",
	vp, vap, cred, p);
#endif /* defined(PCFSDEBUG) */
	if ((vap->va_type != VNON)  ||
	    (vap->va_nlink != VNOVAL)  ||
	    (vap->va_fsid != VNOVAL)  ||
	    (vap->va_fileid != VNOVAL)  ||
	    (vap->va_blocksize != VNOVAL)  ||
	    (vap->va_rdev != VNOVAL)  ||
	    (vap->va_bytes != VNOVAL)  ||
	    (vap->va_gen != VNOVAL)  ||
#if 0
	    (vap->va_uid != (u_short)VNOVAL)  ||
	    (vap->va_gid != (u_short)VNOVAL)  ||
	    (vap->va_atime.tv_sec != VNOVAL)  ||
#endif
	    0) {
#if defined(PCFSDEBUG)
printf("pcfs_setattr(): returning EINVAL\n");
printf("    va_type %d, va_nlink %x, va_fsid %x, va_fileid %x\n",
	vap->va_type, vap->va_nlink, vap->va_fsid, vap->va_fileid);
printf("    va_blocksize %x, va_rdev %x, va_bytes %x, va_gen %x\n",
	vap->va_blocksize, vap->va_rdev, vap->va_bytes, vap->va_gen);
printf("    va_uid %x, va_gid %x, va_atime.tv_sec %x\n",
	vap->va_uid, vap->va_gid, vap->va_atime.tv_sec);
#endif /* defined(PCFSDEBUG) */
		return EINVAL;
	}

	if (vap->va_size != VNOVAL) {
		if (vp->v_type == VDIR)
			return EISDIR;
		if (error = detrunc(dep, vap->va_size, 0))
			return error;
	}
	if (vap->va_mtime.tv_sec != VNOVAL) {
		dep->de_flag |= DEUPD;
		if (error = deupdat(dep, &vap->va_mtime, 1))
			return error;
	}

/*
 *  DOS files only have the ability to have thier
 *  writability attribute set, so we use the owner
 *  write bit to set the readonly attribute.
 */
	if (vap->va_mode != (u_short)VNOVAL) {
		/* We ignore the read and execute bits */
		if (vap->va_mode & VWRITE)
			dep->de_Attributes &= ~ATTR_READONLY;
		else
			dep->de_Attributes |= ATTR_READONLY;
		dep->de_flag |= DEUPD;
	}

	if (vap->va_flags != VNOVAL) {
		if (error = suser(cred, &p->p_acflag))
			return error;
		if (cred->cr_uid == 0)
			dep->de_flag = vap->va_flags;
		else {
			dep->de_flag &= 0xffff0000;
			dep->de_flag |= (vap->va_flags & 0xffff);
		}
		dep->de_flag |= DEUPD;
	}
	return error;
}


int
pcfs_read(vp, uio, ioflag, cred)
	struct vnode *vp;
	struct uio *uio;
	int ioflag;
	struct ucred *cred;
{
	int error = 0;
	int diff;
	int isadir;
	long n;
	long on;
	daddr_t bn;
	daddr_t lbn;
	daddr_t rablock;
	struct buf *bp;
	struct denode *dep = VTODE(vp);
	struct pcfsmount *pmp = dep->de_pmp;

/*
 *  If they didn't ask for any data, then we
 *  are done.
 */
	if (uio->uio_resid == 0)
		return 0;
	if (uio->uio_offset < 0)
		return EINVAL;

	isadir = dep->de_Attributes & ATTR_DIRECTORY;
	do {
		lbn = uio->uio_offset >> pmp->pm_cnshift;
		on  = uio->uio_offset &  pmp->pm_crbomask;
		n = MIN((u_long)(pmp->pm_bpcluster - on), uio->uio_resid);
		diff = dep->de_FileSize - uio->uio_offset;
		if (diff <= 0)
			return 0;
		/* convert cluster # to block # if a directory */
		if (isadir) {
			error = pcbmap(dep, lbn, &lbn, 0);
			if (error)
				return error;
		}
		if (diff < n)
			n = diff;
/*
 *  If we are operating on a directory file then be
 *  sure to do i/o with the vnode for the filesystem
 *  instead of the vnode for the directory.
 */
		if (isadir) {
			error = bread(pmp->pm_devvp, lbn, pmp->pm_bpcluster,
				NOCRED, &bp);
		} else {
			rablock = lbn + 1;
			if (vp->v_lastr + 1 == lbn  &&
			    rablock * pmp->pm_bpcluster < dep->de_FileSize) {
				error = breada(vp, lbn, pmp->pm_bpcluster,
					rablock, pmp->pm_bpcluster, NOCRED, &bp);
			} else {
				error = bread(vp, lbn, pmp->pm_bpcluster, NOCRED,
					&bp);
			}
			vp->v_lastr = lbn;
		}
		if (error) {
			brelse(bp);
			return error;
		}
		n = MIN(n, pmp->pm_bpcluster - bp->b_resid);
		error = uiomove(bp->b_un.b_addr + on, (int)n, uio);
/*
 *  If we have read everything from this block or
 *  have read to end of file then we are done with
 *  this block.  Mark it to say the buffer can be reused if
 *  need be.
 */
#if 0
		if (n + on == pmp->pm_bpcluster  ||
		    uio->uio_offset == dep->de_FileSize)
			bp->b_flags |= B_AGE;
#endif
		brelse(bp);
	} while (error == 0  &&  uio->uio_resid > 0  && n != 0);
	return error;
}

/*
 *  Write data to a file or directory.
 */
int
pcfs_write(vp, uio, ioflag, cred)
	struct vnode *vp;
	struct uio *uio;
	int ioflag;
	struct ucred *cred;
{
	int n;
	int croffset;
	int resid;
	int osize;
	int error;
	u_long cluster;
	u_long nextcluster;
	u_long lastcluster;
	daddr_t bn;
	struct buf *bp;
	struct proc *p = uio->uio_procp;
	struct denode *dep = VTODE(vp);
	struct pcfsmount *pmp = dep->de_pmp;

#if defined(PCFSDEBUG)
printf("pcfs_write(vp %08x, uio %08x, ioflag %08x, cred %08x\n",
	vp, uio, ioflag, cred);
printf("pcfs_write(): diroff %d, dirclust %d, startcluster %d\n",
	dep->de_diroffset, dep->de_dirclust, dep->de_StartCluster);
#endif /* defined(PCFSDEBUG) */

	switch (vp->v_type) {
	case VREG:
		if (ioflag & IO_APPEND)
			uio->uio_offset = dep->de_FileSize;
		break;

	case VDIR:
		/* In pcfs, directory updates don't use pcfs_write */
		panic("pcfs_write(): directory update");
		break;

	default:
		panic("pcfs_write(): bad file type");
		break;
	}

	if (uio->uio_offset < 0)
		return EINVAL;
	if (uio->uio_resid == 0)
		return 0;

/*
 *  If they've exceeded their filesize limit, tell them about it.
 */
	if (vp->v_type == VREG  &&  p  &&
	    ((uio->uio_offset + uio->uio_resid) >
	     p->p_rlimit[RLIMIT_FSIZE].rlim_cur)) {
		psignal(p, SIGXFSZ);
		return EFBIG;
	}

/*
 *  If the offset we are starting the write at is beyond the
 *  end of the file, then they've done a seek.  Unix filesystems
 *  allow files with holes in them, DOS doesn't so we must
 *  fill the hole with zeroed blocks.
 */
	if (uio->uio_offset > dep->de_FileSize) {
		error = pcfsextend(vp, uio->uio_offset);
		if (error)
			return error;
	}

/*
 *  Remember some values in case the write fails.
 */
	resid = uio->uio_resid;
	osize = dep->de_FileSize;

	do {
		bn = uio->uio_offset >> pmp->pm_cnshift;
		croffset = uio->uio_offset & pmp->pm_crbomask;
		n = MIN(uio->uio_resid, pmp->pm_bpcluster-croffset);
/*
 *  If we are appending to the file and we are on a
 *  cluster boundary, then allocate a new cluster
 *  and chain it onto the file.
 */
		if (uio->uio_offset == dep->de_FileSize  &&
		    (uio->uio_offset & pmp->pm_crbomask) == 0) {
			if (error = extendfile(dep, &bp, 0))
				break;
		} else {
/*
 *  The block we need to write into exists,
 *  so just read it in.
 */
			if (n == pmp->pm_bpcluster)
				/* We will overwrite the whole block, so 
				 * dont read it*/
				bp = getblk(vp, bn, pmp->pm_bpcluster);
			else {
				error = bread(vp, bn, pmp->pm_bpcluster, cred, &bp);
				if (error) {
					brelse(bp);
					return error;
				}
			}
		}
		if (uio->uio_offset+n > dep->de_FileSize) {
			dep->de_FileSize = uio->uio_offset + n;
			vnode_pager_setsize(vp, dep->de_FileSize);
		}
		(void) vnode_pager_uncache(vp);

/*
 *  Copy the data from user space into the buf header.
 */
		error = uiomove(bp->b_un.b_addr+croffset, n, uio);

/*
 *  If they want this synchronous then write it and wait
 *  for it.  Otherwise, if on a cluster boundary write it
 *  asynchronously so we can move on to the next block
 *  without delay.  Otherwise do a delayed write because
 *  we may want to write somemore into the block later.
 */
		if (ioflag & IO_SYNC)
			(void) bwrite(bp);
		else
		if (n + croffset == pmp->pm_bpcluster) {
			bp->b_flags |= B_AGE;
			bawrite(bp);
		} else
			bdwrite(bp);
		dep->de_flag |= DEUPD;
	} while (error == 0  &&  uio->uio_resid > 0);

/*
 *  If the write failed and they want us to, truncate
 *  the file back to the size it was before the write
 *  was attempted.
 */
	if (error && (ioflag & IO_UNIT)) {
		detrunc(dep, osize, ioflag & IO_SYNC);
		uio->uio_offset -= resid - uio->uio_resid;
		uio->uio_resid   = resid;
	}
	if (!error && (ioflag & IO_UNIT))
		error = deupdat(dep, &time, 1);
	return error;
}

int
pcfs_ioctl(vp, com, data, fflag, cred, p)
	struct vnode *vp;
	int com;
	caddr_t data;
	struct ucred *cred;
	struct proc *p;
{
	return ENOTTY;
}

int
pcfs_select(vp, which, fflags, cred, p)
	struct vnode *vp;
	int which;
	int fflags;
	struct ucred *cred;
	struct proc *p;
{
	return 1;		/* DOS filesystems never block? */
}

int
pcfs_mmap(vp, fflags, cred, p)
	struct vnode *vp;
	int fflags;
	struct ucred *cred;
	struct proc *p;
{
	return EINVAL;
}

/*
 *  Flush the blocks of a file to disk.
 *
 *  This function is worthless for vnodes that represent
 *  directories.
 *  Maybe we could just do a sync if they try an fsync
 *  on a directory file.
 */
int
pcfs_fsync(vp, fflags, cred, waitfor, p)
	struct vnode *vp;
	int fflags;
	struct ucred *cred;
	int waitfor;
	struct proc *p;
{
	struct denode *dep = VTODE(vp);

	if (fflags & FWRITE)
		dep->de_flag |= DEUPD;

	vflushbuf(vp, waitfor == MNT_WAIT ? B_SYNC : 0);
	return deupdat(dep, &time, waitfor == MNT_WAIT);
}

/*
 *  Since the dos filesystem does not allow files with
 *  holes in them we must fill the file with zeroed
 *  blocks when a write past the end of file happens.
 */
int
pcfsextend(vp, newoff)
	struct vnode *vp;
	off_t newoff;
{
	int error = 0;
	off_t foff;
	struct buf *bp;
	struct denode *dep = VTODE(vp);
	struct pcfsmount *pmp = dep->de_pmp;

#ifdef DIAGNOSTIC
	if (dep->de_Attributes & ATTR_DIRECTORY)
		/* should not happen */
		return EISDIR;
#endif

/*
 *  Compute the offset of the first byte after the
 *  last block in the file.
 *  If writing beyond the end of file then fill the
 *  file with zeroed blocks up to the seek address.
 */
	foff = (dep->de_FileSize + (pmp->pm_bpcluster-1)) & ~pmp->pm_crbomask;
	if (newoff <= foff)
		return 0;

/*
 *  Allocate and chain together as many clusters as
 *  are needed to get to newoff.
 */
	while (foff < newoff) {
		if (error = extendfile(dep, &bp, 0))
			return error;
		bdwrite(bp);
		foff += pmp->pm_bpcluster;
		dep->de_FileSize += pmp->pm_bpcluster;
	}
	dep->de_FileSize = newoff;
	dep->de_flag |= DEUPD;
	return deupdat(dep, &time);
}

/*
 * Seek on a file
 *
 * Nothing to do, so just return.
 */
int
pcfs_seek(vp, oldoff, newoff, cred)
	struct vnode *vp;
	off_t oldoff;
	off_t newoff;
	struct ucred *cred;
{
	return 0;
}

int
pcfs_remove(ndp, p)
	struct nameidata *ndp;
	struct proc *p;
{
	int error;
	struct denode *dep = VTODE(ndp->ni_vp);
	struct denode *ddep = VTODE(ndp->ni_dvp);

	error = removede(ndp);
#if defined(PCFSDEBUG)
printf("pcfs_remove(), dep %08x, v_usecount %d\n", dep, ndp->ni_vp->v_usecount);
#endif /* defined(PCFSDEBUG) */
	if (ddep == dep)
		vrele(DETOV(dep));
	else
		deput(dep);	/* causes pcfs_inactive() to be called via vrele() */
	deput(ddep);
	return error;
}

/*
 *  DOS filesystems don't know what links are.
 */
int
pcfs_link(vp, ndp, p)
	struct vnode *vp;
	struct nameidata *ndp;
	struct proc *p;
{
	return EINVAL;
}

/*
 *  Renames on files require moving the denode to
 *  a new hash queue since the denode's location is
 *  used to compute which hash queue to put the file in.
 *  Unless it is a rename in place.  For example "mv a b".
 *
 *  What follows is the basic algorithm:
 *
 *	if (file move) {
 *		if (dest file exists) {
 *			remove dest file
 *		}
 *		if (dest and src in same directory) {
 *			rewrite name in existing directory slot
 *		} else {
 *			write new entry in dest directory
 *			update offset and dirclust in denode
 *			move denode to new hash chain
 *			clear old directory entry
 *		}
 *	} else {  directory move
 *		if (dest directory exists) {
 *			if (dest is not empty) {
 *				return ENOTEMPTY
 *			}
 *			remove dest directory
 *		}
 *		if (dest and src in same directory) {
 *			rewrite name in existing entry
 *		} else {
 *			be sure dest is not a child of src directory
 *			write entry in dest directory
 *			update "." and ".." in moved directory
 *			update offset and dirclust in denode
 *			move denode to new hash chain
 *			clear old directory entry for moved directory
 *		}
 *	}
 *
 *  On entry:
 *    source's parent directory is unlocked
 *    source file or directory is unlocked
 *    destination's parent directory is locked
 *    destination file or directory is locked if it exists
 *
 *  On exit:
 *    all denodes should be released
 *  Notes:
 *    I'm not sure how the memory containing the pathnames
 *    pointed at by the nameidata structures is freed, there
 *    may be some memory bleeding for each rename done.
 */
int
pcfs_rename(fndp, tndp, p)
	struct nameidata *fndp;
	struct nameidata *tndp;
	struct proc *p;
{
	u_char toname[11];
	int error;
	int newparent = 0;
	int sourceisadirectory = 0;
	u_long to_dirclust;
	u_long to_diroffset;
	u_long cn;
	daddr_t bn;
	struct denode *fddep;	/* from file's parent directory	*/
	struct denode *fdep;	/* from file or directory	*/
	struct denode *tddep;	/* to file's parent directory	*/
	struct denode *tdep;	/* to file or directory		*/
	struct pcfsmount *pmp;
	struct direntry *dotdotp;
	struct direntry *ep;
	struct buf *bp;

#if defined(PCFSDEBUG)
printf("pcfs_rename(fndp %08x, tndp %08x, p %08x\n", fndp, tndp, p);
#endif /* defined(PCFSDEBUG) */
	fddep = VTODE(fndp->ni_dvp);
	fdep  = VTODE(fndp->ni_vp);
	tddep = VTODE(tndp->ni_dvp);
	tdep  = tndp->ni_vp ? VTODE(tndp->ni_vp) : NULL;
	pmp = fddep->de_pmp;

/*
 *  Convert the filename in tdnp into a dos filename.
 *  We copy this into the denode and directory entry
 *  for the destination file/directory.
 */
	unix2dosfn((u_char *)tndp->ni_ptr, toname, tndp->ni_namelen);

/*
 *  At this point this is the lock state of the denodes:
 *   fddep referenced
 *   fdep  referenced
 *   tddep locked
 *   tdep  locked if it exists
 */

/*
 *  Be sure we are not renaming ".", "..", or an alias of ".".
 *  This leads to a crippled directory tree.  It's pretty tough
 *  to do a "ls" or "pwd" with the "." directory entry missing,
 *  and "cd .." doesn't work if the ".." entry is missing.
 */
	if (fdep->de_Attributes & ATTR_DIRECTORY) {
		if ((fndp->ni_namelen == 1  &&  fndp->ni_ptr[0] == '.')  ||
		    fddep == fdep  || /* won't happen ? */
		    fndp->ni_isdotdot) {
			VOP_ABORTOP(tndp);
			vput(tndp->ni_dvp);
			if (tndp->ni_vp)
				vput(tndp->ni_vp);
			VOP_ABORTOP(fndp);
			vrele(fndp->ni_dvp);
			vrele(fndp->ni_vp);
			return EINVAL;
		}
		sourceisadirectory = 1;
	}

/*
 *  If we are renaming a directory, and the directory
 *  is being moved to another directory, then we must
 *  be sure the destination directory is not in the
 *  subtree of the source directory.  This could orphan
 *  everything under the source directory.
 *  doscheckpath() unlocks the destination's parent
 *  directory so we must look it up again to relock it.
 */
	if (fddep->de_StartCluster != tddep->de_StartCluster)
		newparent = 1;
	if (sourceisadirectory && newparent) {
		if (tdep) {
			deput(tdep);
			tdep = NULL;
		}
		/* doscheckpath() deput()'s tddep */
		error = doscheckpath(fdep, tddep, tndp->ni_cred);
		tddep = NULL;
		if (error)
			goto bad;
		if ((tndp->ni_nameiop & SAVESTART) == 0)
			panic("pcfs_rename(): lost to startdir");
		if (error = lookup(tndp, p))
			goto bad;
		tddep = VTODE(tndp->ni_dvp);
		tdep  = tndp->ni_vp ? VTODE(tndp->ni_vp) : NULL;
	}

/*
 *  If the destination exists, then be sure its type (file or dir)
 *  matches that of the source.  And, if it is a directory make
 *  sure it is empty.  Then delete the destination.
 */
	if (tdep) {
		if (tdep->de_Attributes & ATTR_DIRECTORY) {
			if (!sourceisadirectory) {
				error = ENOTDIR;
				goto bad;
			}
			if (!dosdirempty(tdep)) {
				error = ENOTEMPTY;
				goto bad;
			}
		} else {	/* destination is file */
			if (sourceisadirectory) {
				error = EISDIR;
				goto bad;
			}
		}
		to_dirclust = tdep->de_dirclust;
		to_diroffset = tdep->de_diroffset;
		if (error = removede(tndp))
			goto bad;
		deput(tdep);
		tdep = NULL;

/*
 *  Remember where the slot was for createde().
 */
		tndp->ni_pcfs.pcfs_count = 1;
		tndp->ni_pcfs.pcfs_cluster = to_dirclust;
		tndp->ni_pcfs.pcfs_offset  = to_diroffset;
	}

/*
 *  If the source and destination are in the same
 *  directory then just read in the directory entry,
 *  change the name in the directory entry and
 *  write it back to disk.
 */
	if (newparent == 0) {
		/* tddep and fddep point to the same denode here */
		DELOCK(fdep);		/* tddep is already locked */
		if (error = readde(fdep, &bp, &ep)) {
			DEUNLOCK(fdep);
			goto bad;
		}
		bcopy(toname, ep->deName, 11);
		if (error = bwrite(bp)) {
			DEUNLOCK(fdep);
			goto bad;
		}
		bcopy(toname, fdep->de_Name, 11);	/* update denode */
/*
 *  fdep locked
 *  fddep and tddep point to the same denode which is locked
 *  tdep is unlocked and unreferenced
 */
	} else {
		u_long dirsize;
/*
 *  If the source and destination are in different
 *  directories, then mark the entry in the source
 *  directory as deleted and write a new entry in the
 *  destination directory.  Then move the denode to
 *  the correct hash chain for its new location in
 *  the filesystem.  And, if we moved a directory,
 *  then update its .. entry to point to the new
 *  parent directory.
 *  If we moved a directory will also insure that
 *  the directory entry on disk has a filesize of
 *  zero.
 */
		DELOCK(fdep);
		bcopy(toname, fdep->de_Name, 11);	/* update denode */
		if (fdep->de_Attributes & ATTR_DIRECTORY) {
			dirsize = fdep->de_FileSize;
			fdep->de_FileSize = 0;
		}
		error = createde(fdep, tndp, (struct denode **)0);
		if (fdep->de_Attributes & ATTR_DIRECTORY) {
			fdep->de_FileSize = dirsize;
		}
		if (error) {
			/* should put back filename */
			DEUNLOCK(fdep);
			goto bad;
		}
		DELOCK(fddep);
		error = markdeleted (pmp,
				     fndp->ni_pcfs.pcfs_cluster,
				     fndp->ni_pcfs.pcfs_offset);
		if (error) {
			DEUNLOCK(fdep);
			DEUNLOCK(fddep);
			goto bad;
		}
		if (!(fdep->de_Attributes & ATTR_DIRECTORY)) {
			fdep->de_dirclust = tndp->ni_pcfs.pcfs_cluster;
			fdep->de_diroffset = tndp->ni_pcfs.pcfs_offset;
			reinsert(fdep);
		}
		DEUNLOCK(fddep);
	}
	/* fdep is still locked here */

/*
 *  If we moved a directory to a new parent directory,
 *  then we must fixup the ".." entry in the moved
 *  directory.
 */
	if (sourceisadirectory  &&  newparent) {
		cn = fdep->de_StartCluster;
		if (cn == PCFSROOT)
			/* this should never happen */
			panic("pcfs_rename(): updating .. in root directory?\n");
		error = readep(pmp, cn, 1, &bp, &dotdotp);
		if (error) {
			/* should really panic here, fs is corrupt */
			DEUNLOCK(fdep);
			goto bad;
		}
		dotdotp->deStartCluster = tddep->de_StartCluster;
		error = bwrite(bp);
		DEUNLOCK(fdep);
		if (error)
			/* should really panic here, fs is corrupt */
			goto bad;
	}
	else
		DEUNLOCK(fdep);
bad:;
	vrele(DETOV(fdep));
	vrele(DETOV(fddep));
	if (tdep)
		vput(DETOV(tdep));
	if (tddep)
		vput(DETOV(tddep));
	return error;
}

struct {
	struct direntry dot;
	struct direntry dotdot;
} dosdirtemplate = {
	".       ", "   ",		/* the . entry */
	ATTR_DIRECTORY,			/* file attribute */
	0,0,0,0,0,0,0,0,0,0,		/* resevered */
	1234, 1234,			/* time and date */
	0,				/* startcluster */
	0,				/* filesize */
	"..      ", "   ",		/* the .. entry */
	ATTR_DIRECTORY,			/* file attribute */
	0,0,0,0,0,0,0,0,0,0,		/* resevered */
	1234, 1234,			/* time and date */
	0,				/* startcluster */
	0,				/* filesize */
};

int
pcfs_mkdir(ndp, vap, p)
	struct nameidata *ndp;
	struct vattr *vap;
	struct proc *p;
{
	int bn;
	int error;
	u_long newcluster;
	struct denode *pdep;
	struct denode *ndep;
	struct vnode *pvp;
	struct direntry *denp;
	struct denode ndirent;
	struct pcfsmount *pmp;
	struct buf *bp;

	pvp = ndp->ni_dvp;
	pdep = VTODE(pvp);

/*
 *  If this is the root directory and there is no space left
 *  we can't do anything.  This is because the root directory
 *  can not change size.
 */
	if (pdep->de_StartCluster == PCFSROOT  &&  ndp->ni_pcfs.pcfs_count == 0) {
		free(ndp->ni_pnbuf, M_NAMEI);
		deput(pdep);
		return ENOSPC;
	}

	pmp = pdep->de_pmp;

/*
 *  Allocate a cluster to hold the about to be created directory.
 */
	if (error = clusteralloc(pmp, &newcluster, CLUST_EOFE)) {
		free(ndp->ni_pnbuf, M_NAMEI);
		deput(pdep);
		return error;
	}

/*
 *  Now fill the cluster with the "." and ".." entries.
 *  And write the cluster to disk.  This way it is there
 *  for the parent directory to be pointing at if there
 *  were a crash.
 */
	bn = cntobn(pmp, newcluster);
	bp = getblk(pmp->pm_devvp, bn, pmp->pm_bpcluster); /* always succeeds */
	clrbuf(bp);
	bcopy(&dosdirtemplate, bp->b_un.b_addr, sizeof dosdirtemplate);
	denp = (struct direntry *)bp->b_un.b_addr;
	denp->deStartCluster = newcluster;
	unix2dostime(&time, (union dosdate *)&denp->deDate,
		(union dostime *)&denp->deTime);
	denp++;
	denp->deStartCluster = pdep->de_StartCluster;
	unix2dostime(&time, (union dosdate *)&denp->deDate,
		(union dostime *)&denp->deTime);
	if (error = bwrite(bp)) {
		clusterfree(pmp, newcluster, NULL);
		free(ndp->ni_pnbuf, M_NAMEI);
		deput(pdep);
		return error;
	}

/*
 *  Now build up a directory entry pointing to the newly
 *  allocated cluster.  This will be written to an empty
 *  slot in the parent directory.
 */
	ndep = &ndirent;
	bzero(ndep, sizeof(*ndep));
	unix2dosfn((u_char *)ndp->ni_ptr, ndep->de_Name, ndp->ni_namelen);
	unix2dostime(&time, (union dosdate *)&ndep->de_Date,
		(union dostime *)&ndep->de_Time);
	ndep->de_StartCluster = newcluster;
	ndep->de_Attributes = ATTR_DIRECTORY;
	ndep->de_pmp = pmp;	/* createde() needs this	*/

	error = createde(ndep, ndp, &ndep);
	if (error) {
		clusterfree(pmp, newcluster, NULL);
	} else {
		ndp->ni_vp = DETOV(ndep);
	}
	free(ndp->ni_pnbuf, M_NAMEI);
#if defined(PCFSDEBUG)
printf("pcfs_mkdir(): deput(%08x), vnode %08x\n", pdep, DETOV(pdep));
#endif /* defined(PCFSDEBUG) */
	deput(pdep);
	return error;
}

int
pcfs_rmdir(ndp, p)
	struct nameidata *ndp;
	struct proc *p;
{
	struct denode *ddep;
	struct denode *dep;
	int error = 0;

	ddep = VTODE(ndp->ni_dvp);	/* parent dir of dir to delete	*/
	dep  = VTODE(ndp->ni_vp);	/* directory to delete	*/

/*
 *  Don't let "rmdir ." go thru.
 */
	if (ddep == dep) {
		vrele(DETOV(dep));
		deput(dep);
		return EINVAL;
	}

/*
 *  Be sure the directory being deleted is empty.
 */
	if (dosdirempty(dep) == 0) {
		error = ENOTEMPTY;
		goto out;
	}

/*
 *  Delete the entry from the directory.  For dos filesystems
 *  this gets rid of the directory entry on disk, the in memory
 *  copy still exists but the de_refcnt is <= 0.  This prevents
 *  it from being found by deget().  When the deput() on dep is
 *  done we give up access and eventually pcfs_reclaim() will
 *  be called which will remove it from the denode cache.
 */
	if (error = removede(ndp))
		goto out;

/*
 *  This is where we decrement the link count in the parent
 *  directory.  Since dos filesystems don't do this we just
 *  purge the name cache and let go of the parent directory
 *  denode.
 */
	cache_purge(DETOV(ddep));
	deput(ddep);
	ndp->ni_dvp = NULL;	/* getting rid of parent dir pointer? */

/*
 *  Truncate the directory that is being deleted.
 */
	error = detrunc(dep, (u_long)0, IO_SYNC);
	cache_purge(DETOV(dep));

out:;
	if (ndp->ni_dvp)
		deput(ddep);
	deput(dep);
	return error;
}

/*
 *  DOS filesystems don't know what symlinks are.
 */
int
pcfs_symlink(ndp, vap, target, p)
	struct nameidata *ndp;
	struct vattr *vap;
	char *target;
	struct proc *p;
{
	return EINVAL;
}

/*
 *  Dummy dirents to simulate the "." and ".." entries
 *  of the root directory in a dos filesystem.  Dos doesn't
 *  provide these.
 *  Note that each entry must be the same size as a dos
 *  directory entry (32 bytes).
 */
struct dos_dirent {
	u_long d_fileno;
	u_short d_reclen;
	u_short d_namlen;
	u_char d_name[24];
} rootdots[2] = {
    {
	1,				/* d_fileno			*/
	sizeof(struct direntry),	/* d_reclen			*/
	1,				/* d_namlen			*/
	"."				/* d_name			*/
    },
    {
	1,				/* d_fileno			*/
	sizeof(struct direntry),	/* d_reclen			*/
	2,				/* d_namlen			*/
	".."				/* d_name			*/
    }
};

int
pcfs_readdir(vp, uio, cred, eofflagp)
	struct vnode *vp;
	struct uio *uio;
	struct ucred *cred;
	int *eofflagp;
{
	int error = 0;
	int diff;
	char pushout;
	long n;
	long on;
	long lost;
	long count;
	u_long cn;
	u_long fileno;
	long bias = 0;
	daddr_t bn;
	daddr_t lbn;
	struct buf *bp;
	struct denode *dep = VTODE(vp);
	struct pcfsmount *pmp = dep->de_pmp;
	struct direntry *dentp;
	struct dirent *prev;
	struct dirent *crnt;
	u_char dirbuf[512];	/* holds converted dos directories */
int i=0;

#if defined(PCFSDEBUG)
printf("pcfs_readdir(): vp %08x, uio %08x, cred %08x, eofflagp %08x\n",
	vp, uio, cred, eofflagp);
#endif /* defined(PCFSDEBUG) */

/*
 *  pcfs_readdir() won't operate properly on regular files
 *  since it does i/o only with the the filesystem vnode,
 *  and hence can retrieve the wrong block from the buffer
 *  cache for a plain file.  So, fail attempts to readdir()
 *  on a plain file.
 */
	if ((dep->de_Attributes & ATTR_DIRECTORY) == 0)
		return ENOTDIR;

/*
 *  If the user buffer is smaller than the size of one dos
 *  directory entry or the file offset is not a multiple of
 *  the size of a directory entry, then we fail the read.
 */
	count = uio->uio_resid & ~(sizeof(struct direntry)-1);
	lost  = uio->uio_resid - count;
	if (count < sizeof(struct direntry)  ||
	    (uio->uio_offset & (sizeof(struct direntry)-1)))
		return EINVAL;
	uio->uio_resid = count;
	uio->uio_iov->iov_len = count;

/*
 *  If they are reading from the root directory then,
 *  we simulate the . and .. entries since these don't
 *  exist in the root directory.  We also set the offset
 *  bias to make up for having to simulate these entries.
 *  By this I mean that at file offset 64 we read the first entry
 *  in the root directory that lives on disk.
 */
	if (dep->de_StartCluster == PCFSROOT) {
/*printf("pcfs_readdir(): going after . or .. in root dir, offset %d\n",
	uio->uio_offset);*/
		bias = 2*sizeof(struct direntry);
		if (uio->uio_offset < 2*sizeof(struct direntry)) {
			error = uiomove((char *)rootdots + uio->uio_offset,
				sizeof rootdots - uio->uio_offset, uio);
			if (error)
				goto out;
		}
	}
	do {
		lbn = (uio->uio_offset-bias) >> pmp->pm_cnshift;
		on  = (uio->uio_offset-bias) &  pmp->pm_crbomask;
		n = MIN((u_long)(pmp->pm_bpcluster - on), uio->uio_resid);
		diff = dep->de_FileSize - (uio->uio_offset - bias);
		if (diff <= 0)
			return 0;
		if (diff < n)
			n = diff;
		error = pcbmap(dep, lbn, &bn, &cn);
		if (error)
			break;
		error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster, NOCRED, &bp);
		if (error) {
			brelse(bp);
			return error;
		}
		n = MIN(n, pmp->pm_bpcluster - bp->b_resid);

/*
 *  code to convert from dos directory entries to ufs directory entries
 */
		pushout = 0;
		dentp = (struct direntry *)(bp->b_un.b_addr + on);
		prev = 0;
		crnt = (struct dirent *)dirbuf;
		while ((char *)dentp < bp->b_un.b_addr + on + n) {
/*printf("rd: dentp %08x prev %08x crnt %08x deName %02x attr %02x\n",
	dentp, prev, crnt, dentp->deName[0], dentp->deAttributes);*/
/*
 *  If we have an empty entry or a slot from a deleted
 *  file, or a volume label entry just concatenate its
 *  space onto the end of the previous entry or,
 *  manufacture an empty entry if there is no previous
 *  entry.
 */
			if (dentp->deName[0] == SLOT_EMPTY  ||
			    dentp->deName[0] == SLOT_DELETED  ||
			    (dentp->deAttributes & ATTR_VOLUME)) {
				if (prev) {
					prev->d_reclen += sizeof(struct direntry);
				} else {
					prev = crnt;
					prev->d_fileno = 0;
					prev->d_reclen = sizeof(struct direntry);
					prev->d_namlen = 0;
					prev->d_name[0] = 0;
				}
			} else {
				/* this computation of d_fileno must match
				 * the computation of va_fileid in pcfs_getattr */
				if (dentp->deAttributes & ATTR_DIRECTORY) {
					/* if this is the root directory */
					if ((fileno = dentp->deStartCluster) == PCFSROOT)
						fileno = 1;
				} else {
					/* if the file's dirent lives in root dir */
					if ((fileno = cn) == PCFSROOT)
						fileno = 1;
					fileno = (fileno << 16) |
						((dentp - (struct direntry *)bp->b_un.b_addr) & 0xffff);
				}
				crnt->d_fileno = fileno;
				crnt->d_reclen = sizeof(struct direntry);
				crnt->d_namlen = dos2unixfn(dentp->deName,
					(u_char *)crnt->d_name);
/*printf("readdir: file %s, fileno %08x, attr %02x, start %08x\n",
	crnt->d_name, crnt->d_fileno, dentp->deAttributes, dentp->deStartCluster);*/
				prev = crnt;
			}
			crnt = (struct dirent *)((char *)crnt + sizeof(struct direntry));
			pushout = 1;

/*
 *  If our intermediate buffer is full then copy
 *  its contents to user space.
 */
			if ((u_char *)crnt >= &dirbuf[sizeof dirbuf]) {
				pushout = 0;
				error = uiomove(dirbuf, sizeof(dirbuf), uio);
				if (error)
					break;
				prev = 0;
				crnt = (struct dirent *)dirbuf;
			}
			dentp++;
		}
		if (pushout) {
			pushout = 0;
			error = uiomove(dirbuf, (char *)crnt - (char *)dirbuf,
				uio);
		}

/*
 *  If we have read everything from this block or
 *  have read to end of file then we are done with
 *  this block.  Mark it to say the buffer can be reused if
 *  need be.
 */
#if 0
		if (n + on == pmp->pm_bpcluster  ||
		    (uio->uio_offset-bias) == dep->de_FileSize)
			bp->b_flags |= B_AGE;
#endif
		brelse(bp);
	} while (error == 0  &&  uio->uio_resid > 0  && n != 0);
out:;
	uio->uio_resid += lost;

/*
 *  I don't know why we bother setting this eofflag, getdirentries()
 *  in vfs_syscalls.c doesn't bother to look at it when we return.
 *	But nfsrv_readdir does. 
 */
	if (dep->de_FileSize - uio->uio_offset - bias <= 0)
		*eofflagp = 1;
	else
		*eofflagp = 0;
	return error;
}

/*
 *  DOS filesystems don't know what symlinks are.
 */
int
pcfs_readlink(vp, uio, cred)
	struct vnode *vp;
	struct uio *uio;
	struct ucred *cred;
{
	return EINVAL;
}

int
pcfs_abortop(ndp)
	struct nameidata *ndp;
{
	if ((ndp->ni_nameiop & (HASBUF | SAVESTART)) == HASBUF)
		FREE(ndp->ni_pnbuf, M_NAMEI);
	return 0;
}

int
pcfs_lock(vp)
	struct vnode *vp;
{
	struct denode *dep = VTODE(vp);

	DELOCK(dep);
	return 0;
}

int
pcfs_unlock(vp)
	struct vnode *vp;
{
	struct denode *dep = VTODE(vp);

	if (!(dep->de_flag & DELOCKED))
		panic("pcfs_unlock: denode not locked");
	DEUNLOCK(dep);
	return 0;
}

int
pcfs_islocked(vp)
	struct vnode *vp;
{
	return VTODE(vp)->de_flag & DELOCKED ? 1 : 0;
}

/*
 *  vp - address of vnode file the file
 *  bn - which cluster we are interested in mapping to
 *    a filesystem block number.
 *  vpp - returns the vnode for the block special file
 *    holding the filesystem containing the file of interest
 *  bnp - address of where to return the filesystem
 *    relative block number
 */
int
pcfs_bmap(vp, bn, vpp, bnp)
	struct vnode *vp;
	daddr_t bn;
	struct vnode **vpp;
	daddr_t *bnp;
{
	struct denode *dep = VTODE(vp);
	struct pcfsmount *pmp = dep->de_pmp;

	if (vpp != NULL)
		*vpp = dep->de_devvp;
	if (bnp == NULL)
		return 0;
	return pcbmap(dep, bn << (pmp->pm_cnshift - pmp->pm_bnshift), bnp, 0);
}

int
pcfs_strategy(bp)
	struct buf *bp;
{
	struct denode *dep = VTODE(bp->b_vp);
	struct pcfsmount *pmp = dep->de_pmp;
	struct vnode *vp;
	int error;

	if (bp->b_vp->v_type == VBLK  ||  bp->b_vp->v_type == VCHR)
		panic("pcfs_strategy: spec");
/*
 *  If we don't already know the filesystem relative
 *  block number then get it using pcbmap().  If pcbmap()
 *  returns the block number as -1 then we've got a hole
 *  in the file.  DOS filesystems don't allow files with
 *  holes, so we shouldn't ever see this.
 */
	if (bp->b_blkno == bp->b_lblkno) {
		if (error = pcbmap(dep, bp->b_lblkno, &bp->b_blkno, 0))
			return error;
		if ((long)bp->b_blkno == -1)
			clrbuf(bp);
	}
	if ((long)bp->b_blkno == -1) {
		biodone(bp);
		return 0;
	}
#ifdef DIAGNOSTIC
#endif /* defined(DIAGNOSTIC) */
/*
 *  Read/write the block from/to the disk that contains the desired
 *  file block.
 */
	vp = dep->de_devvp;
	bp->b_dev = vp->v_rdev;
	(*(vp->v_op->vop_strategy))(bp);
	return 0;
}

int
pcfs_print(vp)
	struct vnode *vp;
{
	struct denode *dep = VTODE(vp);

	printf("tag VT_MSDOSFS, startcluster %d, dircluster %d, diroffset %d ",
		dep->de_StartCluster, dep->de_dirclust, dep->de_diroffset);
	printf(" dev %d, %d, %s\n",
		major(dep->de_dev), minor(dep->de_dev),
		dep->de_flag & DELOCKED ? "(LOCKED)" : "");
	if (dep->de_spare0) {
		printf("    owner pid %d", dep->de_spare0);
		if (dep->de_spare1)
			printf(" waiting pid %d", dep->de_spare1);
		printf("\n");
	}
}

int