text: /* $FreeBSD: releng/11.0/sys/fs/msdosfs/denode.h 234605 2012-04-23 13:21:28Z trasz $ */
  /*	$NetBSD: denode.h,v 1.25 1997/11/17 15:36:28 ws Exp $	*/
  
  /*-
   * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
   * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
   * All rights reserved.
   * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *	This product includes software developed by TooLs GmbH.
   * 4. The name of TooLs GmbH may not be used to endorse or promote products
   *    derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
   * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
   * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
   * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
   * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
   * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  /*-
   * 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
   */
  
  /*
   * This is the pc filesystem specific portion of the vnode structure.
   *
   * To describe a file uniquely the de_dirclust, de_diroffset, and
   * de_StartCluster fields are used.
   *
   * de_dirclust contains the cluster number of the directory cluster
   *	containing the entry for a file or directory.
   * de_diroffset is the index into the cluster for the entry describing
   *	a file or directory.
   * de_StartCluster is the number of the first cluster of the file or directory.
   *
   * Now to describe the quirks of the pc filesystem.
   * - Clusters 0 and 1 are reserved.
   * - The first allocatable cluster is 2.
   * - The root directory is of fixed size and all blocks that make it up
   *   are contiguous.
   * - Cluster 0 refers to the root directory when it is found in the
   *   startcluster field of a directory entry that points to another directory.
   * - Cluster 0 implies a 0 length file when found in the start cluster field
   *   of a directory entry that points to a file.
   * - You can't use the cluster number 0 to derive the address of the root
   *   directory.
   * - Multiple directory entries can point to a directory. The entry in the
   *   parent directory points to a child directory.  Any directories in the
   *   child directory contain a ".." entry that points back to the parent.
   *   The child directory itself contains a "." entry that points to itself.
   * - The root directory does not contain a "." or ".." entry.
   * - Directory entries for directories are never changed once they are created
   *   (except when removed).  The size stays 0, and the last modification time
   *   is never changed.  This is because so many directory entries can point to
   *   the physical clusters that make up a directory.  It would lead to an
   *   update nightmare.
   * - The length field in a directory entry pointing to a directory contains 0
   *   (always).  The only way to find the end of a directory is to follow the
   *   cluster chain until the "last cluster" marker is found.
   *
   * My extensions to make this house of cards work.  These apply only to the in
   * memory copy of the directory entry.
   * - A reference count for each denode will be kept since dos doesn't keep such
   *   things.
   */
  
  /*
   * Internal pseudo-offset for (nonexistent) directory entry for the root
   * dir in the root dir
   */
  #define	MSDOSFSROOT_OFS	0x1fffffff
  
  /*
   * The fat cache structure. fc_fsrcn is the filesystem relative cluster
   * number that corresponds to the file relative cluster number in this
   * structure (fc_frcn).
   */
  struct fatcache {
  	u_long fc_frcn;		/* file relative cluster number */
  	u_long fc_fsrcn;	/* filesystem relative cluster number */
  };
  
  /*
   * The fat entry cache as it stands helps make extending files a "quick"
   * operation by avoiding having to scan the fat to discover the last
   * cluster of the file. The cache also helps sequential reads by
   * remembering the last cluster read from the file.  This also prevents us
   * from having to rescan the fat to find the next cluster to read.  This
   * cache is probably pretty worthless if a file is opened by multiple
   * processes.
   */
  #define	FC_SIZE		3	/* number of entries in the cache */
  #define	FC_LASTMAP	0	/* entry the last call to pcbmap() resolved
  				 * to */
  #define	FC_LASTFC	1	/* entry for the last cluster in the file */
  #define	FC_NEXTTOLASTFC	2	/* entry for a close to the last cluster in
  				 * the file */
  
  #define	FCE_EMPTY	0xffffffff	/* doesn't represent an actual cluster # */
  
  /*
   * Set a slot in the fat cache.
   */
  #define	fc_setcache(dep, slot, frcn, fsrcn) \
  	(dep)->de_fc[(slot)].fc_frcn = (frcn); \
  	(dep)->de_fc[(slot)].fc_fsrcn = (fsrcn);
  
  /*
   * This is the in memory variant of a dos directory entry.  It is usually
   * contained within a vnode.
   */
  struct denode {
  	struct vnode *de_vnode;	/* addr of vnode we are part of */
  	u_long de_flag;		/* flag bits */
  	u_long de_dirclust;	/* cluster of the directory file containing this entry */
  	u_long de_diroffset;	/* offset of this entry in the directory cluster */
  	u_long de_fndoffset;	/* offset of found dir entry */
  	int de_fndcnt;		/* number of slots before de_fndoffset */
  	long de_refcnt;		/* reference count */
  	struct msdosfsmount *de_pmp;	/* addr of our mount struct */
  	u_char de_Name[12];	/* name, from DOS directory entry */
  	u_char de_Attributes;	/* attributes, from directory entry */
  	u_char de_LowerCase;	/* NT VFAT lower case flags */
  	u_char de_CHun;		/* Hundredth of second of CTime*/
  	u_short de_CTime;	/* creation time */
  	u_short de_CDate;	/* creation date */
  	u_short de_ADate;	/* access date */
  	u_short de_MTime;	/* modification time */
  	u_short de_MDate;	/* modification date */
  	u_long de_StartCluster; /* starting cluster of file */
  	u_long de_FileSize;	/* size of file in bytes */
  	struct fatcache de_fc[FC_SIZE];	/* fat cache */
  	u_quad_t de_modrev;	/* Revision level for lease. */
  	u_int64_t de_inode;	/* Inode number (really byte offset of direntry) */
  };
  
  /*
   * Values for the de_flag field of the denode.
   */
  #define	DE_UPDATE	0x0004	/* Modification time update request */
  #define	DE_CREATE	0x0008	/* Creation time update */
  #define	DE_ACCESS	0x0010	/* Access time update */
  #define	DE_MODIFIED	0x0020	/* Denode has been modified */
  #define	DE_RENAME	0x0040	/* Denode is in the process of being renamed */
  
  
  /*
   * Transfer directory entries between internal and external form.
   * dep is a struct denode * (internal form),
   * dp is a struct direntry * (external form).
   */
  #define DE_INTERNALIZE32(dep, dp)			\
  	 ((dep)->de_StartCluster |= getushort((dp)->deHighClust) << 16)
  #define DE_INTERNALIZE(dep, dp)				\
  	(bcopy((dp)->deName, (dep)->de_Name, 11),	\
  	 (dep)->de_Attributes = (dp)->deAttributes,	\
  	 (dep)->de_LowerCase = (dp)->deLowerCase,	\
  	 (dep)->de_CHun = (dp)->deCHundredth,		\
  	 (dep)->de_CTime = getushort((dp)->deCTime),	\
  	 (dep)->de_CDate = getushort((dp)->deCDate),	\
  	 (dep)->de_ADate = getushort((dp)->deADate),	\
  	 (dep)->de_MTime = getushort((dp)->deMTime),	\
  	 (dep)->de_MDate = getushort((dp)->deMDate),	\
  	 (dep)->de_StartCluster = getushort((dp)->deStartCluster), \
  	 (dep)->de_FileSize = getulong((dp)->deFileSize), \
  	 (FAT32((dep)->de_pmp) ? DE_INTERNALIZE32((dep), (dp)) : 0))
  
  #define DE_EXTERNALIZE(dp, dep)				\
  	(bcopy((dep)->de_Name, (dp)->deName, 11),	\
  	 (dp)->deAttributes = (dep)->de_Attributes,	\
  	 (dp)->deLowerCase = (dep)->de_LowerCase,	\
  	 (dp)->deCHundredth = (dep)->de_CHun,		\
  	 putushort((dp)->deCTime, (dep)->de_CTime),	\
  	 putushort((dp)->deCDate, (dep)->de_CDate),	\
  	 putushort((dp)->deADate, (dep)->de_ADate),	\
  	 putushort((dp)->deMTime, (dep)->de_MTime),	\
  	 putushort((dp)->deMDate, (dep)->de_MDate),	\
  	 putushort((dp)->deStartCluster, (dep)->de_StartCluster), \
  	 putulong((dp)->deFileSize,			\
  	     ((dep)->de_Attributes & ATTR_DIRECTORY) ? 0 : (dep)->de_FileSize), \
  	 putushort((dp)->deHighClust, (dep)->de_StartCluster >> 16))
  
  #ifdef _KERNEL
  
  #define	VTODE(vp)	((struct denode *)(vp)->v_data)
  #define	DETOV(de)	((de)->de_vnode)
  
  #define	DETIMES(dep, acc, mod, cre) do {				\
  	if ((dep)->de_flag & DE_UPDATE) {				\
  		(dep)->de_flag |= DE_MODIFIED;				\
  		timespec2fattime((mod), 0, &(dep)->de_MDate,		\
  		    &(dep)->de_MTime, NULL);				\
  		(dep)->de_Attributes |= ATTR_ARCHIVE;			\
  	}								\
  	if ((dep)->de_pmp->pm_flags & MSDOSFSMNT_NOWIN95) {		\
  		(dep)->de_flag &= ~(DE_UPDATE | DE_CREATE | DE_ACCESS);	\
  		break;							\
  	}								\
  	if ((dep)->de_flag & DE_ACCESS) {				\
  		u_int16_t adate;					\
  									\
  		timespec2fattime((acc), 0, &adate, NULL, NULL);		\
  		if (adate != (dep)->de_ADate) {				\
  			(dep)->de_flag |= DE_MODIFIED;			\
  			(dep)->de_ADate = adate;			\
  		}							\
  	}								\
  	if ((dep)->de_flag & DE_CREATE) {				\
  		timespec2fattime((cre), 0, &(dep)->de_CDate,		\
  		    &(dep)->de_CTime, &(dep)->de_CHun);			\
  		(dep)->de_flag |= DE_MODIFIED;				\
  	}								\
  	(dep)->de_flag &= ~(DE_UPDATE | DE_CREATE | DE_ACCESS);		\
  } while (0)
  
  /*
   * This overlays the fid structure (see mount.h)
   */
  struct defid {
  	u_short defid_len;	/* length of structure */
  	u_short defid_pad;	/* force long alignment */
  
  	u_int32_t defid_dirclust; /* cluster this dir entry came from */
  	u_int32_t defid_dirofs;	/* offset of entry within the cluster */
  #if 0
  	u_int32_t defid_gen;	/* generation number */
  #endif
  };
  
  extern struct vop_vector msdosfs_vnodeops;
  
  int msdosfs_lookup(struct vop_cachedlookup_args *);
  int msdosfs_inactive(struct vop_inactive_args *);
  int msdosfs_reclaim(struct vop_reclaim_args *);
  
  /*
   * Internal service routine prototypes.
   */
  int deget(struct msdosfsmount *, u_long, u_long, struct denode **);
  int uniqdosname(struct denode *, struct componentname *, u_char *);
  int findwin95(struct denode *);
  
  int readep(struct msdosfsmount *pmp, u_long dirclu, u_long dirofs,  struct buf **bpp, struct direntry **epp);
  int readde(struct denode *dep, struct buf **bpp, struct direntry **epp);
  int deextend(struct denode *dep, u_long length, struct ucred *cred);
  int fillinusemap(struct msdosfsmount *pmp);
  void reinsert(struct denode *dep);
  int dosdirempty(struct denode *dep);
  int createde(struct denode *dep, struct denode *ddep, struct denode **depp, struct componentname *cnp);
  int deupdat(struct denode *dep, int waitfor);
  int removede(struct denode *pdep, struct denode *dep);
  int detrunc(struct denode *dep, u_long length, int flags, struct ucred *cred);
  int doscheckpath( struct denode *source, struct denode *target);
  #endif	/* _KERNEL */
  