FreeBSD/Linux Kernel Cross Reference
sys/fs/msdosfs/msdosfs_denode.c

     /* $FreeBSD$ */
     /*      $NetBSD: msdosfs_denode.c,v 1.28 1998/02/10 14:10:00 mrg 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
     */
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/mount.h>
    #include <sys/malloc.h>
    #include <sys/bio.h>
    #include <sys/buf.h>
    #include <sys/vnode.h>
    #include <sys/mutex.h>
    
    #include <vm/vm.h>
    #include <vm/vm_extern.h>
    
    #include <fs/msdosfs/bpb.h>
    #include <fs/msdosfs/msdosfsmount.h>
    #include <fs/msdosfs/direntry.h>
    #include <fs/msdosfs/denode.h>
    #include <fs/msdosfs/fat.h>
    
    static MALLOC_DEFINE(M_MSDOSFSNODE, "MSDOSFS node", "MSDOSFS vnode private part");
    
    static int
    de_vncmpf(struct vnode *vp, void *arg)
    {
            struct denode *de;
            uint64_t *a;
    
            a = arg;
            de = VTODE(vp);
            return (de->de_inode != *a);
    }
    
    /*
     * If deget() succeeds it returns with the gotten denode locked().
     *
     * pmp       - address of msdosfsmount structure of the filesystem containing
     *             the denode of interest.  The address of
     *             the msdosfsmount structure are used.
     * dirclust  - which cluster bp contains, if dirclust is 0 (root directory)
     *             diroffset is relative to the beginning of the root directory,
     *             otherwise it is cluster relative.
     * diroffset - offset past begin of cluster of denode we want
     * depp      - returns the address of the gotten denode.
     */
    int
    deget(pmp, dirclust, diroffset, depp)
            struct msdosfsmount *pmp;       /* so we know the maj/min number */
            u_long dirclust;                /* cluster this dir entry came from */
            u_long diroffset;               /* index of entry within the cluster */
           struct denode **depp;           /* returns the addr of the gotten denode */
   {
           int error;
           uint64_t inode;
           struct mount *mntp = pmp->pm_mountp;
           struct direntry *direntptr;
           struct denode *ldep;
           struct vnode *nvp, *xvp;
           struct buf *bp;
   
   #ifdef MSDOSFS_DEBUG
           printf("deget(pmp %p, dirclust %lu, diroffset %lx, depp %p)\n",
               pmp, dirclust, diroffset, depp);
   #endif
   
           /*
            * On FAT32 filesystems, root is a (more or less) normal
            * directory
            */
           if (FAT32(pmp) && dirclust == MSDOSFSROOT)
                   dirclust = pmp->pm_rootdirblk;
   
           /*
            * See if the denode is in the denode cache. Use the location of
            * the directory entry to compute the hash value. For subdir use
            * address of "." entry. For root dir (if not FAT32) use cluster
            * MSDOSFSROOT, offset MSDOSFSROOT_OFS
            *
            * NOTE: The check for de_refcnt > 0 below insures the denode being
            * examined does not represent an unlinked but still open file.
            * These files are not to be accessible even when the directory
            * entry that represented the file happens to be reused while the
            * deleted file is still open.
            */
           inode = (uint64_t)pmp->pm_bpcluster * dirclust + diroffset;
   
           error = vfs_hash_get(mntp, inode, LK_EXCLUSIVE, curthread, &nvp,
               de_vncmpf, &inode);
           if (error)
                   return(error);
           if (nvp != NULL) {
                   *depp = VTODE(nvp);
                   KASSERT((*depp)->de_dirclust == dirclust, ("wrong dirclust"));
                   KASSERT((*depp)->de_diroffset == diroffset, ("wrong diroffset"));
                   return (0);
           }
   
           /*
            * Do the MALLOC before the getnewvnode since doing so afterward
            * might cause a bogus v_data pointer to get dereferenced
            * elsewhere if MALLOC should block.
            */
           MALLOC(ldep, struct denode *, sizeof(struct denode), M_MSDOSFSNODE, M_WAITOK);
   
           /*
            * Directory entry was not in cache, have to create a vnode and
            * copy it from the passed disk buffer.
            */
           /* getnewvnode() does a VREF() on the vnode */
           error = getnewvnode("msdosfs", mntp, &msdosfs_vnodeops, &nvp);
           if (error) {
                   *depp = NULL;
                   FREE(ldep, M_MSDOSFSNODE);
                   return error;
           }
           bzero((caddr_t)ldep, sizeof *ldep);
           nvp->v_data = ldep;
           ldep->de_vnode = nvp;
           ldep->de_flag = 0;
           ldep->de_dirclust = dirclust;
           ldep->de_diroffset = diroffset;
           ldep->de_inode = inode;
           fc_purge(ldep, 0);      /* init the fat cache for this denode */
   
           error = vfs_hash_insert(nvp, inode, LK_EXCLUSIVE, curthread, &xvp,
               de_vncmpf, &inode);
           if (error) {
                   *depp = NULL;
                   return (error);
           }
           if (xvp != NULL) {
                   /* XXX: Not sure this is right */
                   nvp = xvp;
                   ldep->de_vnode = nvp;
           }
   
           ldep->de_pmp = pmp;
           ldep->de_refcnt = 1;
           /*
            * Copy the directory entry into the denode area of the vnode.
            */
           if ((dirclust == MSDOSFSROOT
                || (FAT32(pmp) && dirclust == pmp->pm_rootdirblk))
               && diroffset == MSDOSFSROOT_OFS) {
                   /*
                    * Directory entry for the root directory. There isn't one,
                    * so we manufacture one. We should probably rummage
                    * through the root directory and find a label entry (if it
                    * exists), and then use the time and date from that entry
                    * as the time and date for the root denode.
                    */
                   nvp->v_vflag |= VV_ROOT; /* should be further down XXX */
   
                   ldep->de_Attributes = ATTR_DIRECTORY;
                   ldep->de_LowerCase = 0;
                   if (FAT32(pmp))
                           ldep->de_StartCluster = pmp->pm_rootdirblk;
                           /* de_FileSize will be filled in further down */
                   else {
                           ldep->de_StartCluster = MSDOSFSROOT;
                           ldep->de_FileSize = pmp->pm_rootdirsize * DEV_BSIZE;
                   }
                   /*
                    * fill in time and date so that dos2unixtime() doesn't
                    * spit up when called from msdosfs_getattr() with root
                    * denode
                    */
                   ldep->de_CHun = 0;
                   ldep->de_CTime = 0x0000;        /* 00:00:00      */
                   ldep->de_CDate = (0 << DD_YEAR_SHIFT) | (1 << DD_MONTH_SHIFT)
                       | (1 << DD_DAY_SHIFT);
                   /* Jan 1, 1980   */
                   ldep->de_ADate = ldep->de_CDate;
                   ldep->de_MTime = ldep->de_CTime;
                   ldep->de_MDate = ldep->de_CDate;
                   /* leave the other fields as garbage */
           } else {
                   error = readep(pmp, dirclust, diroffset, &bp, &direntptr);
                   if (error) {
                           /*
                            * The denode does not contain anything useful, so
                            * it would be wrong to leave it on its hash chain.
                            * Arrange for vput() to just forget about it.
                            */
                           ldep->de_Name[0] = SLOT_DELETED;
   
                           vput(nvp);
                           *depp = NULL;
                           return (error);
                   }
                   DE_INTERNALIZE(ldep, direntptr);
                   brelse(bp);
           }
   
           /*
            * Fill in a few fields of the vnode and finish filling in the
            * denode.  Then return the address of the found denode.
            */
           if (ldep->de_Attributes & ATTR_DIRECTORY) {
                   /*
                    * Since DOS directory entries that describe directories
                    * have 0 in the filesize field, we take this opportunity
                    * to find out the length of the directory and plug it into
                    * the denode structure.
                    */
                   u_long size;
   
                   /*
                    * XXX Sometimes, these arrives that . entry have cluster
                    * number 0, when it shouldn't.  Use real cluster number
                    * instead of what is written in directory entry.
                    */
                   if ((diroffset == 0) && (ldep->de_StartCluster != dirclust)) {
                           printf("deget(): . entry at clust %ld != %ld\n",
                                           dirclust, ldep->de_StartCluster);
                           ldep->de_StartCluster = dirclust;
                   }
   
                   nvp->v_type = VDIR;
                   if (ldep->de_StartCluster != MSDOSFSROOT) {
                           error = pcbmap(ldep, 0xffff, 0, &size, 0);
                           if (error == E2BIG) {
                                   ldep->de_FileSize = de_cn2off(pmp, size);
                                   error = 0;
                           } else
                                   printf("deget(): pcbmap returned %d\n", error);
                   }
           } else
                   nvp->v_type = VREG;
           ldep->de_modrev = init_va_filerev();
           *depp = ldep;
           return (0);
   }
   
   int
   deupdat(dep, waitfor)
           struct denode *dep;
           int waitfor;
   {
           int error;
           struct buf *bp;
           struct direntry *dirp;
           struct timespec ts;
   
           if (DETOV(dep)->v_mount->mnt_flag & MNT_RDONLY)
                   return (0);
           getnanotime(&ts);
           DETIMES(dep, &ts, &ts, &ts);
           if ((dep->de_flag & DE_MODIFIED) == 0)
                   return (0);
           dep->de_flag &= ~DE_MODIFIED;
           if (dep->de_Attributes & ATTR_DIRECTORY)
                   return (0);
           if (dep->de_refcnt <= 0)
                   return (0);
           error = readde(dep, &bp, &dirp);
           if (error)
                   return (error);
           DE_EXTERNALIZE(dirp, dep);
           if (waitfor)
                   return (bwrite(bp));
           else {
                   bdwrite(bp);
                   return (0);
           }
   }
   
   /*
    * Truncate the file described by dep to the length specified by length.
    */
   int
   detrunc(dep, length, flags, cred, td)
           struct denode *dep;
           u_long length;
           int flags;
           struct ucred *cred;
           struct thread *td;
   {
           int error;
           int allerror;
           u_long eofentry;
           u_long chaintofree;
           daddr_t bn;
           int boff;
           int isadir = dep->de_Attributes & ATTR_DIRECTORY;
           struct buf *bp;
           struct msdosfsmount *pmp = dep->de_pmp;
   
   #ifdef MSDOSFS_DEBUG
           printf("detrunc(): file %s, length %lu, flags %x\n", dep->de_Name, length, flags);
   #endif
   
           /*
            * Disallow attempts to truncate the root directory since it is of
            * fixed size.  That's just the way dos filesystems are.  We use
            * the VROOT bit in the vnode because checking for the directory
            * bit and a startcluster of 0 in the denode is not adequate to
            * recognize the root directory at this point in a file or
            * directory's life.
            */
           if ((DETOV(dep)->v_vflag & VV_ROOT) && !FAT32(pmp)) {
                   printf("detrunc(): can't truncate root directory, clust %ld, offset %ld\n",
                       dep->de_dirclust, dep->de_diroffset);
                   return (EINVAL);
           }
   
   
           if (dep->de_FileSize < length) {
                   vnode_pager_setsize(DETOV(dep), length);
                   return deextend(dep, length, cred);
           }
   
           /*
            * If the desired length is 0 then remember the starting cluster of
            * the file and set the StartCluster field in the directory entry
            * to 0.  If the desired length is not zero, then get the number of
            * the last cluster in the shortened file.  Then get the number of
            * the first cluster in the part of the file that is to be freed.
            * Then set the next cluster pointer in the last cluster of the
            * file to CLUST_EOFE.
            */
           if (length == 0) {
                   chaintofree = dep->de_StartCluster;
                   dep->de_StartCluster = 0;
                   eofentry = ~0;
           } else {
                   error = pcbmap(dep, de_clcount(pmp, length) - 1, 0, 
                                  &eofentry, 0);
                   if (error) {
   #ifdef MSDOSFS_DEBUG
                           printf("detrunc(): pcbmap fails %d\n", error);
   #endif
                           return (error);
                   }
           }
   
           fc_purge(dep, de_clcount(pmp, length));
   
           /*
            * If the new length is not a multiple of the cluster size then we
            * must zero the tail end of the new last cluster in case it
            * becomes part of the file again because of a seek.
            */
           if ((boff = length & pmp->pm_crbomask) != 0) {
                   if (isadir) {
                           bn = cntobn(pmp, eofentry);
                           error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster,
                               NOCRED, &bp);
                           if (error) {
                                   brelse(bp);
   #ifdef MSDOSFS_DEBUG
                                   printf("detrunc(): bread fails %d\n", error);
   #endif
                                   return (error);
                           }
                           bzero(bp->b_data + boff, pmp->pm_bpcluster - boff);
                           if (flags & IO_SYNC)
                                   bwrite(bp);
                           else
                                   bdwrite(bp);
                   }
           }
   
           /*
            * Write out the updated directory entry.  Even if the update fails
            * we free the trailing clusters.
            */
           dep->de_FileSize = length;
           if (!isadir)
                   dep->de_flag |= DE_UPDATE|DE_MODIFIED;
           allerror = vtruncbuf(DETOV(dep), cred, td, length, pmp->pm_bpcluster);
   #ifdef MSDOSFS_DEBUG
           if (allerror)
                   printf("detrunc(): vtruncbuf error %d\n", allerror);
   #endif
           error = deupdat(dep, 1);
           if (error && (allerror == 0))
                   allerror = error;
   #ifdef MSDOSFS_DEBUG
           printf("detrunc(): allerror %d, eofentry %lu\n",
                  allerror, eofentry);
   #endif
   
           /*
            * If we need to break the cluster chain for the file then do it
            * now.
            */
           if (eofentry != ~0) {
                   error = fatentry(FAT_GET_AND_SET, pmp, eofentry,
                                    &chaintofree, CLUST_EOFE);
                   if (error) {
   #ifdef MSDOSFS_DEBUG
                           printf("detrunc(): fatentry errors %d\n", error);
   #endif
                           return (error);
                   }
                   fc_setcache(dep, FC_LASTFC, de_cluster(pmp, length - 1),
                               eofentry);
           }
   
           /*
            * Now free the clusters removed from the file because of the
            * truncation.
            */
           if (chaintofree != 0 && !MSDOSFSEOF(pmp, chaintofree))
                   freeclusterchain(pmp, chaintofree);
   
           return (allerror);
   }
   
   /*
    * Extend the file described by dep to length specified by length.
    */
   int
   deextend(dep, length, cred)
           struct denode *dep;
           u_long length;
           struct ucred *cred;
   {
           struct msdosfsmount *pmp = dep->de_pmp;
           u_long count;
           int error;
   
           /*
            * The root of a DOS filesystem cannot be extended.
            */
           if ((DETOV(dep)->v_vflag & VV_ROOT) && !FAT32(pmp))
                   return (EINVAL);
   
           /*
            * Directories cannot be extended.
            */
           if (dep->de_Attributes & ATTR_DIRECTORY)
                   return (EISDIR);
   
           if (length <= dep->de_FileSize)
                   panic("deextend: file too large");
   
           /*
            * Compute the number of clusters to allocate.
            */
           count = de_clcount(pmp, length) - de_clcount(pmp, dep->de_FileSize);
           if (count > 0) {
                   if (count > pmp->pm_freeclustercount)
                           return (ENOSPC);
                   error = extendfile(dep, count, NULL, NULL, DE_CLEAR);
                   if (error) {
                           /* truncate the added clusters away again */
                           (void) detrunc(dep, dep->de_FileSize, 0, cred, NULL);
                           return (error);
                   }
           }
           dep->de_FileSize = length;
           dep->de_flag |= DE_UPDATE|DE_MODIFIED;
           return (deupdat(dep, 1));
   }
   
   /*
    * Move a denode to its correct hash queue after the file it represents has
    * been moved to a new directory.
    */
   void
   reinsert(dep)
           struct denode *dep;
   {
           struct vnode *vp;
   
           /*
            * Fix up the denode cache.  If the denode is for a directory,
            * there is nothing to do since the hash is based on the starting
            * cluster of the directory file and that hasn't changed.  If for a
            * file the hash is based on the location of the directory entry,
            * so we must remove it from the cache and re-enter it with the
            * hash based on the new location of the directory entry.
            */
   #if 0
           if (dep->de_Attributes & ATTR_DIRECTORY)
                   return;
   #endif
           vp = DETOV(dep);
           dep->de_inode = (uint64_t)dep->de_pmp->pm_bpcluster * dep->de_dirclust +
                dep->de_diroffset;
           vfs_hash_rehash(vp, dep->de_inode);
   }
   
   int
   msdosfs_reclaim(ap)
           struct vop_reclaim_args /* {
                   struct vnode *a_vp;
           } */ *ap;
   {
           struct vnode *vp = ap->a_vp;
           struct denode *dep = VTODE(vp);
   
   #ifdef MSDOSFS_DEBUG
           printf("msdosfs_reclaim(): dep %p, file %s, refcnt %ld\n",
               dep, dep->de_Name, dep->de_refcnt);
   #endif
   
           if (prtactive && vrefcnt(vp) != 0)
                   vprint("msdosfs_reclaim(): pushing active", vp);
           /*
            * Destroy the vm object and flush associated pages.
            */
           vnode_destroy_vobject(vp);
           /*
            * Remove the denode from its hash chain.
            */
           vfs_hash_remove(vp);
           /*
            * Purge old data structures associated with the denode.
            */
   #if 0 /* XXX */
           dep->de_flag = 0;
   #endif
           FREE(dep, M_MSDOSFSNODE);
           vp->v_data = NULL;
   
           return (0);
   }
   
   int
   msdosfs_inactive(ap)
           struct vop_inactive_args /* {
                   struct vnode *a_vp;
                   struct thread *a_td;
           } */ *ap;
   {
           struct vnode *vp = ap->a_vp;
           struct denode *dep = VTODE(vp);
           struct thread *td = ap->a_td;
           int error = 0;
   
   #ifdef MSDOSFS_DEBUG
           printf("msdosfs_inactive(): dep %p, de_Name[0] %x\n", dep, dep->de_Name[0]);
   #endif
   
           if (prtactive && vrefcnt(vp) != 0)
                   vprint("msdosfs_inactive(): pushing active", vp);
   
           /*
            * Ignore denodes related to stale file handles.
            */
           if (dep->de_Name[0] == SLOT_DELETED)
                   goto out;
   
           /*
            * If the file has been deleted and it is on a read/write
            * filesystem, then truncate the file, and mark the directory slot
            * as empty.  (This may not be necessary for the dos filesystem.)
            */
   #ifdef MSDOSFS_DEBUG
           printf("msdosfs_inactive(): dep %p, refcnt %ld, mntflag %x, MNT_RDONLY %x\n",
                  dep, dep->de_refcnt, vp->v_mount->mnt_flag, MNT_RDONLY);
   #endif
           if (dep->de_refcnt <= 0 && (vp->v_mount->mnt_flag & MNT_RDONLY) == 0) {
                   error = detrunc(dep, (u_long) 0, 0, NOCRED, td);
                   dep->de_flag |= DE_UPDATE;
                   dep->de_Name[0] = SLOT_DELETED;
           }
           deupdat(dep, 0);
   
   out:
           /*
            * If we are done with the denode, reclaim it
            * so that it can be reused immediately.
            */
   #ifdef MSDOSFS_DEBUG
           printf("msdosfs_inactive(): v_usecount %d, de_Name[0] %x\n",
                  vrefcnt(vp), dep->de_Name[0]);
   #endif
           if (dep->de_Name[0] == SLOT_DELETED)
                   vrecycle(vp, td);
           return (error);
   }

Cache object: c97087bccbee345b43dfa3f24b3a621f