FreeBSD/Linux Kernel Cross Reference
sys/fs/msdosfs/denode.h

     /* $FreeBSD$ */
     /*      $NetBSD: denode.h,v 1.25 1997/11/17 15:36:28 ws Exp $   */
     
     /*-
      * SPDX-License-Identifier: BSD-4-Clause
      *
      * 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
     */
    #ifndef _FS_MSDOSFS_DENODE_H_
    #define _FS_MSDOSFS_DENODE_H_
    
    /*
     * 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 */
           struct vn_clusterw de_clusterw; /* buffer clustering information */
           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. */
           uint64_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 */
   
   /* Maximum size of a file on a FAT filesystem */
   #define MSDOSFS_FILESIZE_MAX    0xFFFFFFFFLL
   
   /*
    * 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)                         \
           (memcpy((dep)->de_Name, (dp)->deName, 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)                         \
           (memcpy((dp)->deName, (dep)->de_Name, 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))
   
   #if defined(_KERNEL) || defined(MAKEFS)
   
   #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) {                               \
                   uint16_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 */
   
           uint32_t defid_dirclust; /* cluster this dir entry came from */
           uint32_t defid_dirofs;  /* offset of entry within the cluster */
   #if 0
           uint32_t defid_gen;     /* generation number */
   #endif
   };
   
   extern struct vop_vector msdosfs_vnodeops;
   
   #ifdef _KERNEL
   int msdosfs_lookup(struct vop_cachedlookup_args *);
   int msdosfs_inactive(struct vop_inactive_args *);
   int msdosfs_reclaim(struct vop_reclaim_args *);
   int msdosfs_lookup_ino(struct vnode *vdp, struct vnode **vpp,
       struct componentname *cnp, daddr_t *scnp, u_long *blkoffp);
   #endif
   
   /*
    * Internal service routine prototypes.
    */
   struct componentname;
   int deget(struct msdosfsmount *, u_long, u_long, int, struct denode **);
   int uniqdosname(struct denode *, struct componentname *, u_char *);
   
   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,
       daddr_t *wait_scn);
   #endif  /* _KERNEL || MAKEFS */
   #endif  /* !_FS_MSDOSFS_DENODE_H_ */

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