The Design and Implementation of the FreeBSD Operating System, Second Edition
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sys/fs/msdosfs/msdosfs_vnops.c

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    1 /* $FreeBSD: releng/9.0/sys/fs/msdosfs/msdosfs_vnops.c 218909 2011-02-21 09:01:34Z brucec $ */
    2 /*      $NetBSD: msdosfs_vnops.c,v 1.68 1998/02/10 14:10:04 mrg Exp $   */
    3 
    4 /*-
    5  * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
    6  * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
    7  * All rights reserved.
    8  * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 3. All advertising materials mentioning features or use of this software
   19  *    must display the following acknowledgement:
   20  *      This product includes software developed by TooLs GmbH.
   21  * 4. The name of TooLs GmbH may not be used to endorse or promote products
   22  *    derived from this software without specific prior written permission.
   23  *
   24  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
   25  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   26  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   27  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   29  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
   30  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
   31  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
   32  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
   33  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   34  */
   35 /*-
   36  * Written by Paul Popelka (paulp@uts.amdahl.com)
   37  *
   38  * You can do anything you want with this software, just don't say you wrote
   39  * it, and don't remove this notice.
   40  *
   41  * This software is provided "as is".
   42  *
   43  * The author supplies this software to be publicly redistributed on the
   44  * understanding that the author is not responsible for the correct
   45  * functioning of this software in any circumstances and is not liable for
   46  * any damages caused by this software.
   47  *
   48  * October 1992
   49  */
   50 
   51 #include <sys/param.h>
   52 #include <sys/systm.h>
   53 #include <sys/bio.h>
   54 #include <sys/buf.h>
   55 #include <sys/clock.h>
   56 #include <sys/dirent.h>
   57 #include <sys/lock.h>
   58 #include <sys/lockf.h>
   59 #include <sys/malloc.h>
   60 #include <sys/mount.h>
   61 #include <sys/mutex.h>
   62 #include <sys/namei.h>
   63 #include <sys/priv.h>
   64 #include <sys/stat.h>
   65 #include <sys/unistd.h>
   66 #include <sys/vnode.h>
   67 
   68 #include <vm/vm.h>
   69 #include <vm/vm_extern.h>
   70 
   71 #include <fs/msdosfs/bpb.h>
   72 #include <fs/msdosfs/direntry.h>
   73 #include <fs/msdosfs/denode.h>
   74 #include <fs/msdosfs/fat.h>
   75 #include <fs/msdosfs/msdosfsmount.h>
   76 
   77 #define DOS_FILESIZE_MAX        0xffffffff
   78 
   79 /*
   80  * Prototypes for MSDOSFS vnode operations
   81  */
   82 static vop_create_t     msdosfs_create;
   83 static vop_mknod_t      msdosfs_mknod;
   84 static vop_open_t       msdosfs_open;
   85 static vop_close_t      msdosfs_close;
   86 static vop_access_t     msdosfs_access;
   87 static vop_getattr_t    msdosfs_getattr;
   88 static vop_setattr_t    msdosfs_setattr;
   89 static vop_read_t       msdosfs_read;
   90 static vop_write_t      msdosfs_write;
   91 static vop_fsync_t      msdosfs_fsync;
   92 static vop_remove_t     msdosfs_remove;
   93 static vop_link_t       msdosfs_link;
   94 static vop_rename_t     msdosfs_rename;
   95 static vop_mkdir_t      msdosfs_mkdir;
   96 static vop_rmdir_t      msdosfs_rmdir;
   97 static vop_symlink_t    msdosfs_symlink;
   98 static vop_readdir_t    msdosfs_readdir;
   99 static vop_bmap_t       msdosfs_bmap;
  100 static vop_strategy_t   msdosfs_strategy;
  101 static vop_print_t      msdosfs_print;
  102 static vop_pathconf_t   msdosfs_pathconf;
  103 static vop_vptofh_t     msdosfs_vptofh;
  104 
  105 /*
  106  * Some general notes:
  107  *
  108  * In the ufs filesystem the inodes, superblocks, and indirect blocks are
  109  * read/written using the vnode for the filesystem. Blocks that represent
  110  * the contents of a file are read/written using the vnode for the file
  111  * (including directories when they are read/written as files). This
  112  * presents problems for the dos filesystem because data that should be in
  113  * an inode (if dos had them) resides in the directory itself.  Since we
  114  * must update directory entries without the benefit of having the vnode
  115  * for the directory we must use the vnode for the filesystem.  This means
  116  * that when a directory is actually read/written (via read, write, or
  117  * readdir, or seek) we must use the vnode for the filesystem instead of
  118  * the vnode for the directory as would happen in ufs. This is to insure we
  119  * retreive the correct block from the buffer cache since the hash value is
  120  * based upon the vnode address and the desired block number.
  121  */
  122 
  123 /*
  124  * Create a regular file. On entry the directory to contain the file being
  125  * created is locked.  We must release before we return. We must also free
  126  * the pathname buffer pointed at by cnp->cn_pnbuf, always on error, or
  127  * only if the SAVESTART bit in cn_flags is clear on success.
  128  */
  129 static int
  130 msdosfs_create(ap)
  131         struct vop_create_args /* {
  132                 struct vnode *a_dvp;
  133                 struct vnode **a_vpp;
  134                 struct componentname *a_cnp;
  135                 struct vattr *a_vap;
  136         } */ *ap;
  137 {
  138         struct componentname *cnp = ap->a_cnp;
  139         struct denode ndirent;
  140         struct denode *dep;
  141         struct denode *pdep = VTODE(ap->a_dvp);
  142         struct timespec ts;
  143         int error;
  144 
  145 #ifdef MSDOSFS_DEBUG
  146         printf("msdosfs_create(cnp %p, vap %p\n", cnp, ap->a_vap);
  147 #endif
  148 
  149         /*
  150          * If this is the root directory and there is no space left we
  151          * can't do anything.  This is because the root directory can not
  152          * change size.
  153          */
  154         if (pdep->de_StartCluster == MSDOSFSROOT
  155             && pdep->de_fndoffset >= pdep->de_FileSize) {
  156                 error = ENOSPC;
  157                 goto bad;
  158         }
  159 
  160         /*
  161          * Create a directory entry for the file, then call createde() to
  162          * have it installed. NOTE: DOS files are always executable.  We
  163          * use the absence of the owner write bit to make the file
  164          * readonly.
  165          */
  166 #ifdef DIAGNOSTIC
  167         if ((cnp->cn_flags & HASBUF) == 0)
  168                 panic("msdosfs_create: no name");
  169 #endif
  170         bzero(&ndirent, sizeof(ndirent));
  171         error = uniqdosname(pdep, cnp, ndirent.de_Name);
  172         if (error)
  173                 goto bad;
  174 
  175         ndirent.de_Attributes = (ap->a_vap->va_mode & VWRITE) ?
  176                                 ATTR_ARCHIVE : ATTR_ARCHIVE | ATTR_READONLY;
  177         ndirent.de_LowerCase = 0;
  178         ndirent.de_StartCluster = 0;
  179         ndirent.de_FileSize = 0;
  180         ndirent.de_pmp = pdep->de_pmp;
  181         ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE;
  182         getnanotime(&ts);
  183         DETIMES(&ndirent, &ts, &ts, &ts);
  184         error = createde(&ndirent, pdep, &dep, cnp);
  185         if (error)
  186                 goto bad;
  187         *ap->a_vpp = DETOV(dep);
  188         return (0);
  189 
  190 bad:
  191         return (error);
  192 }
  193 
  194 static int
  195 msdosfs_mknod(ap)
  196         struct vop_mknod_args /* {
  197                 struct vnode *a_dvp;
  198                 struct vnode **a_vpp;
  199                 struct componentname *a_cnp;
  200                 struct vattr *a_vap;
  201         } */ *ap;
  202 {
  203 
  204     return (EINVAL);
  205 }
  206 
  207 static int
  208 msdosfs_open(ap)
  209         struct vop_open_args /* {
  210                 struct vnode *a_vp;
  211                 int a_mode;
  212                 struct ucred *a_cred;
  213                 struct thread *a_td;
  214                 struct file *a_fp;
  215         } */ *ap;
  216 {
  217         struct denode *dep = VTODE(ap->a_vp);
  218         vnode_create_vobject(ap->a_vp, dep->de_FileSize, ap->a_td);
  219         return 0;
  220 }
  221 
  222 static int
  223 msdosfs_close(ap)
  224         struct vop_close_args /* {
  225                 struct vnode *a_vp;
  226                 int a_fflag;
  227                 struct ucred *a_cred;
  228                 struct thread *a_td;
  229         } */ *ap;
  230 {
  231         struct vnode *vp = ap->a_vp;
  232         struct denode *dep = VTODE(vp);
  233         struct timespec ts;
  234 
  235         VI_LOCK(vp);
  236         if (vp->v_usecount > 1) {
  237                 getnanotime(&ts);
  238                 DETIMES(dep, &ts, &ts, &ts);
  239         }
  240         VI_UNLOCK(vp);
  241         return 0;
  242 }
  243 
  244 static int
  245 msdosfs_access(ap)
  246         struct vop_access_args /* {
  247                 struct vnode *a_vp;
  248                 accmode_t a_accmode;
  249                 struct ucred *a_cred;
  250                 struct thread *a_td;
  251         } */ *ap;
  252 {
  253         struct vnode *vp = ap->a_vp;
  254         struct denode *dep = VTODE(ap->a_vp);
  255         struct msdosfsmount *pmp = dep->de_pmp;
  256         mode_t file_mode;
  257         accmode_t accmode = ap->a_accmode;
  258 
  259         file_mode = (S_IXUSR|S_IXGRP|S_IXOTH) | (S_IRUSR|S_IRGRP|S_IROTH) |
  260             ((dep->de_Attributes & ATTR_READONLY) ? 0 : (S_IWUSR|S_IWGRP|S_IWOTH));
  261         file_mode &= (vp->v_type == VDIR ? pmp->pm_dirmask : pmp->pm_mask);
  262 
  263         /*
  264          * Disallow writing to directories and regular files if the
  265          * filesystem is read-only.
  266          */
  267         if (accmode & VWRITE) {
  268                 switch (vp->v_type) {
  269                 case VDIR:
  270                 case VREG:
  271                         if (vp->v_mount->mnt_flag & MNT_RDONLY)
  272                                 return (EROFS);
  273                         break;
  274                 default:
  275                         break;
  276                 }
  277         }
  278 
  279         return (vaccess(vp->v_type, file_mode, pmp->pm_uid, pmp->pm_gid,
  280             ap->a_accmode, ap->a_cred, NULL));
  281 }
  282 
  283 static int
  284 msdosfs_getattr(ap)
  285         struct vop_getattr_args /* {
  286                 struct vnode *a_vp;
  287                 struct vattr *a_vap;
  288                 struct ucred *a_cred;
  289         } */ *ap;
  290 {
  291         struct denode *dep = VTODE(ap->a_vp);
  292         struct msdosfsmount *pmp = dep->de_pmp;
  293         struct vattr *vap = ap->a_vap;
  294         mode_t mode;
  295         struct timespec ts;
  296         u_long dirsperblk = pmp->pm_BytesPerSec / sizeof(struct direntry);
  297         uint64_t fileid;
  298 
  299         getnanotime(&ts);
  300         DETIMES(dep, &ts, &ts, &ts);
  301         vap->va_fsid = dev2udev(pmp->pm_dev);
  302         /*
  303          * The following computation of the fileid must be the same as that
  304          * used in msdosfs_readdir() to compute d_fileno. If not, pwd
  305          * doesn't work.
  306          */
  307         if (dep->de_Attributes & ATTR_DIRECTORY) {
  308                 fileid = (uint64_t)cntobn(pmp, dep->de_StartCluster) *
  309                     dirsperblk;
  310                 if (dep->de_StartCluster == MSDOSFSROOT)
  311                         fileid = 1;
  312         } else {
  313                 fileid = (uint64_t)cntobn(pmp, dep->de_dirclust) *
  314                     dirsperblk;
  315                 if (dep->de_dirclust == MSDOSFSROOT)
  316                         fileid = (uint64_t)roottobn(pmp, 0) * dirsperblk;
  317                 fileid += (uoff_t)dep->de_diroffset / sizeof(struct direntry);
  318         }
  319 
  320         if (pmp->pm_flags & MSDOSFS_LARGEFS)
  321                 vap->va_fileid = msdosfs_fileno_map(pmp->pm_mountp, fileid);
  322         else
  323                 vap->va_fileid = (long)fileid;
  324 
  325         if ((dep->de_Attributes & ATTR_READONLY) == 0)
  326                 mode = S_IRWXU|S_IRWXG|S_IRWXO;
  327         else
  328                 mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH;
  329         vap->va_mode = mode & 
  330             (ap->a_vp->v_type == VDIR ? pmp->pm_dirmask : pmp->pm_mask);
  331         vap->va_uid = pmp->pm_uid;
  332         vap->va_gid = pmp->pm_gid;
  333         vap->va_nlink = 1;
  334         vap->va_rdev = NODEV;
  335         vap->va_size = dep->de_FileSize;
  336         fattime2timespec(dep->de_MDate, dep->de_MTime, 0, 0, &vap->va_mtime);
  337         vap->va_ctime = vap->va_mtime;
  338         if (pmp->pm_flags & MSDOSFSMNT_LONGNAME) {
  339                 fattime2timespec(dep->de_ADate, 0, 0, 0, &vap->va_atime);
  340                 fattime2timespec(dep->de_CDate, dep->de_CTime, dep->de_CHun,
  341                     0, &vap->va_birthtime);
  342         } else {
  343                 vap->va_atime = vap->va_mtime;
  344                 vap->va_birthtime.tv_sec = -1;
  345                 vap->va_birthtime.tv_nsec = 0;
  346         }
  347         vap->va_flags = 0;
  348         if ((dep->de_Attributes & ATTR_ARCHIVE) == 0)
  349                 vap->va_flags |= SF_ARCHIVED;
  350         vap->va_gen = 0;
  351         vap->va_blocksize = pmp->pm_bpcluster;
  352         vap->va_bytes =
  353             (dep->de_FileSize + pmp->pm_crbomask) & ~pmp->pm_crbomask;
  354         vap->va_type = ap->a_vp->v_type;
  355         vap->va_filerev = dep->de_modrev;
  356         return (0);
  357 }
  358 
  359 static int
  360 msdosfs_setattr(ap)
  361         struct vop_setattr_args /* {
  362                 struct vnode *a_vp;
  363                 struct vattr *a_vap;
  364                 struct ucred *a_cred;
  365         } */ *ap;
  366 {
  367         struct vnode *vp = ap->a_vp;
  368         struct denode *dep = VTODE(ap->a_vp);
  369         struct msdosfsmount *pmp = dep->de_pmp;
  370         struct vattr *vap = ap->a_vap;
  371         struct ucred *cred = ap->a_cred;
  372         struct thread *td = curthread;
  373         int error = 0;
  374 
  375 #ifdef MSDOSFS_DEBUG
  376         printf("msdosfs_setattr(): vp %p, vap %p, cred %p\n",
  377             ap->a_vp, vap, cred);
  378 #endif
  379 
  380         /*
  381          * Check for unsettable attributes.
  382          */
  383         if ((vap->va_type != VNON) || (vap->va_nlink != VNOVAL) ||
  384             (vap->va_fsid != VNOVAL) || (vap->va_fileid != VNOVAL) ||
  385             (vap->va_blocksize != VNOVAL) || (vap->va_rdev != VNOVAL) ||
  386             (vap->va_bytes != VNOVAL) || (vap->va_gen != VNOVAL)) {
  387 #ifdef MSDOSFS_DEBUG
  388                 printf("msdosfs_setattr(): returning EINVAL\n");
  389                 printf("    va_type %d, va_nlink %x, va_fsid %lx, va_fileid %lx\n",
  390                     vap->va_type, vap->va_nlink, vap->va_fsid, vap->va_fileid);
  391                 printf("    va_blocksize %lx, va_rdev %x, va_bytes %qx, va_gen %lx\n",
  392                     vap->va_blocksize, vap->va_rdev, vap->va_bytes, vap->va_gen);
  393                 printf("    va_uid %x, va_gid %x\n",
  394                     vap->va_uid, vap->va_gid);
  395 #endif
  396                 return (EINVAL);
  397         }
  398         if (vap->va_flags != VNOVAL) {
  399                 if (vp->v_mount->mnt_flag & MNT_RDONLY)
  400                         return (EROFS);
  401                 if (cred->cr_uid != pmp->pm_uid) {
  402                         error = priv_check_cred(cred, PRIV_VFS_ADMIN, 0);
  403                         if (error)
  404                                 return (error);
  405                 }
  406                 /*
  407                  * We are very inconsistent about handling unsupported
  408                  * attributes.  We ignored the access time and the
  409                  * read and execute bits.  We were strict for the other
  410                  * attributes.
  411                  *
  412                  * Here we are strict, stricter than ufs in not allowing
  413                  * users to attempt to set SF_SETTABLE bits or anyone to
  414                  * set unsupported bits.  However, we ignore attempts to
  415                  * set ATTR_ARCHIVE for directories `cp -pr' from a more
  416                  * sensible filesystem attempts it a lot.
  417                  */
  418                 if (vap->va_flags & SF_SETTABLE) {
  419                         error = priv_check_cred(cred, PRIV_VFS_SYSFLAGS, 0);
  420                         if (error)
  421                                 return (error);
  422                 }
  423                 if (vap->va_flags & ~SF_ARCHIVED)
  424                         return EOPNOTSUPP;
  425                 if (vap->va_flags & SF_ARCHIVED)
  426                         dep->de_Attributes &= ~ATTR_ARCHIVE;
  427                 else if (!(dep->de_Attributes & ATTR_DIRECTORY))
  428                         dep->de_Attributes |= ATTR_ARCHIVE;
  429                 dep->de_flag |= DE_MODIFIED;
  430         }
  431 
  432         if (vap->va_uid != (uid_t)VNOVAL || vap->va_gid != (gid_t)VNOVAL) {
  433                 uid_t uid;
  434                 gid_t gid;
  435 
  436                 if (vp->v_mount->mnt_flag & MNT_RDONLY)
  437                         return (EROFS);
  438                 uid = vap->va_uid;
  439                 if (uid == (uid_t)VNOVAL)
  440                         uid = pmp->pm_uid;
  441                 gid = vap->va_gid;
  442                 if (gid == (gid_t)VNOVAL)
  443                         gid = pmp->pm_gid;
  444                 if (cred->cr_uid != pmp->pm_uid || uid != pmp->pm_uid ||
  445                     (gid != pmp->pm_gid && !groupmember(gid, cred))) {
  446                         error = priv_check_cred(cred, PRIV_VFS_CHOWN, 0);
  447                         if (error)
  448                                 return (error);
  449                 }
  450                 if (uid != pmp->pm_uid || gid != pmp->pm_gid)
  451                         return EINVAL;
  452         }
  453 
  454         if (vap->va_size != VNOVAL) {
  455                 switch (vp->v_type) {
  456                 case VDIR:
  457                         return (EISDIR);
  458                 case VREG:
  459                         /*
  460                          * Truncation is only supported for regular files,
  461                          * Disallow it if the filesystem is read-only.
  462                          */
  463                         if (vp->v_mount->mnt_flag & MNT_RDONLY)
  464                                 return (EROFS);
  465                         break;
  466                 default:
  467                         /*
  468                          * According to POSIX, the result is unspecified
  469                          * for file types other than regular files,
  470                          * directories and shared memory objects.  We
  471                          * don't support any file types except regular
  472                          * files and directories in this file system, so
  473                          * this (default) case is unreachable and can do
  474                          * anything.  Keep falling through to detrunc()
  475                          * for now.
  476                          */
  477                         break;
  478                 }
  479                 error = detrunc(dep, vap->va_size, 0, cred, td);
  480                 if (error)
  481                         return error;
  482         }
  483         if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) {
  484                 if (vp->v_mount->mnt_flag & MNT_RDONLY)
  485                         return (EROFS);
  486                 if (vap->va_vaflags & VA_UTIMES_NULL) {
  487                         error = VOP_ACCESS(vp, VADMIN, cred, td); 
  488                         if (error)
  489                                 error = VOP_ACCESS(vp, VWRITE, cred, td);
  490                 } else
  491                         error = VOP_ACCESS(vp, VADMIN, cred, td);
  492                 if (vp->v_type != VDIR) {
  493                         if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95) == 0 &&
  494                             vap->va_atime.tv_sec != VNOVAL) {
  495                                 dep->de_flag &= ~DE_ACCESS;
  496                                 timespec2fattime(&vap->va_atime, 0,
  497                                     &dep->de_ADate, NULL, NULL);
  498                         }
  499                         if (vap->va_mtime.tv_sec != VNOVAL) {
  500                                 dep->de_flag &= ~DE_UPDATE;
  501                                 timespec2fattime(&vap->va_mtime, 0,
  502                                     &dep->de_MDate, &dep->de_MTime, NULL);
  503                         }
  504                         dep->de_Attributes |= ATTR_ARCHIVE;
  505                         dep->de_flag |= DE_MODIFIED;
  506                 }
  507         }
  508         /*
  509          * DOS files only have the ability to have their writability
  510          * attribute set, so we use the owner write bit to set the readonly
  511          * attribute.
  512          */
  513         if (vap->va_mode != (mode_t)VNOVAL) {
  514                 if (vp->v_mount->mnt_flag & MNT_RDONLY)
  515                         return (EROFS);
  516                 if (cred->cr_uid != pmp->pm_uid) {
  517                         error = priv_check_cred(cred, PRIV_VFS_ADMIN, 0);
  518                         if (error)
  519                                 return (error);
  520                 }
  521                 if (vp->v_type != VDIR) {
  522                         /* We ignore the read and execute bits. */
  523                         if (vap->va_mode & VWRITE)
  524                                 dep->de_Attributes &= ~ATTR_READONLY;
  525                         else
  526                                 dep->de_Attributes |= ATTR_READONLY;
  527                         dep->de_Attributes |= ATTR_ARCHIVE;
  528                         dep->de_flag |= DE_MODIFIED;
  529                 }
  530         }
  531         return (deupdat(dep, 0));
  532 }
  533 
  534 static int
  535 msdosfs_read(ap)
  536         struct vop_read_args /* {
  537                 struct vnode *a_vp;
  538                 struct uio *a_uio;
  539                 int a_ioflag;
  540                 struct ucred *a_cred;
  541         } */ *ap;
  542 {
  543         int error = 0;
  544         int blsize;
  545         int isadir;
  546         int orig_resid;
  547         u_int n;
  548         u_long diff;
  549         u_long on;
  550         daddr_t lbn;
  551         daddr_t rablock;
  552         int rasize;
  553         int seqcount;
  554         struct buf *bp;
  555         struct vnode *vp = ap->a_vp;
  556         struct denode *dep = VTODE(vp);
  557         struct msdosfsmount *pmp = dep->de_pmp;
  558         struct uio *uio = ap->a_uio;
  559 
  560         /*
  561          * If they didn't ask for any data, then we are done.
  562          */
  563         orig_resid = uio->uio_resid;
  564         if (orig_resid == 0)
  565                 return (0);
  566 
  567         /*
  568          * The caller is supposed to ensure that
  569          * uio->uio_offset >= 0 and uio->uio_resid >= 0.
  570          * We don't need to check for large offsets as in ffs because
  571          * dep->de_FileSize <= DOS_FILESIZE_MAX < OFF_MAX, so large
  572          * offsets cannot cause overflow even in theory.
  573          */
  574 
  575         seqcount = ap->a_ioflag >> IO_SEQSHIFT;
  576 
  577         isadir = dep->de_Attributes & ATTR_DIRECTORY;
  578         do {
  579                 if (uio->uio_offset >= dep->de_FileSize)
  580                         break;
  581                 lbn = de_cluster(pmp, uio->uio_offset);
  582                 rablock = lbn + 1;
  583                 blsize = pmp->pm_bpcluster;
  584                 on = uio->uio_offset & pmp->pm_crbomask;
  585                 /*
  586                  * If we are operating on a directory file then be sure to
  587                  * do i/o with the vnode for the filesystem instead of the
  588                  * vnode for the directory.
  589                  */
  590                 if (isadir) {
  591                         /* convert cluster # to block # */
  592                         error = pcbmap(dep, lbn, &lbn, 0, &blsize);
  593                         if (error == E2BIG) {
  594                                 error = EINVAL;
  595                                 break;
  596                         } else if (error)
  597                                 break;
  598                         error = bread(pmp->pm_devvp, lbn, blsize, NOCRED, &bp);
  599                 } else if (de_cn2off(pmp, rablock) >= dep->de_FileSize) {
  600                         error = bread(vp, lbn, blsize, NOCRED, &bp);
  601                 } else if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) {
  602                         error = cluster_read(vp, dep->de_FileSize, lbn, blsize,
  603                             NOCRED, on + uio->uio_resid, seqcount, &bp);
  604                 } else if (seqcount > 1) {
  605                         rasize = blsize;
  606                         error = breadn(vp, lbn,
  607                             blsize, &rablock, &rasize, 1, NOCRED, &bp);
  608                 } else {
  609                         error = bread(vp, lbn, blsize, NOCRED, &bp);
  610                 }
  611                 if (error) {
  612                         brelse(bp);
  613                         break;
  614                 }
  615                 diff = pmp->pm_bpcluster - on;
  616                 n = diff > uio->uio_resid ? uio->uio_resid : diff;
  617                 diff = dep->de_FileSize - uio->uio_offset;
  618                 if (diff < n)
  619                         n = diff;
  620                 diff = blsize - bp->b_resid;
  621                 if (diff < n)
  622                         n = diff;
  623                 error = uiomove(bp->b_data + on, (int) n, uio);
  624                 brelse(bp);
  625         } while (error == 0 && uio->uio_resid > 0 && n != 0);
  626         if (!isadir && (error == 0 || uio->uio_resid != orig_resid) &&
  627             (vp->v_mount->mnt_flag & MNT_NOATIME) == 0)
  628                 dep->de_flag |= DE_ACCESS;
  629         return (error);
  630 }
  631 
  632 /*
  633  * Write data to a file or directory.
  634  */
  635 static int
  636 msdosfs_write(ap)
  637         struct vop_write_args /* {
  638                 struct vnode *a_vp;
  639                 struct uio *a_uio;
  640                 int a_ioflag;
  641                 struct ucred *a_cred;
  642         } */ *ap;
  643 {
  644         int n;
  645         int croffset;
  646         int resid;
  647         u_long osize;
  648         int error = 0;
  649         u_long count;
  650         int seqcount;
  651         daddr_t bn, lastcn;
  652         struct buf *bp;
  653         int ioflag = ap->a_ioflag;
  654         struct uio *uio = ap->a_uio;
  655         struct vnode *vp = ap->a_vp;
  656         struct vnode *thisvp;
  657         struct denode *dep = VTODE(vp);
  658         struct msdosfsmount *pmp = dep->de_pmp;
  659         struct ucred *cred = ap->a_cred;
  660 
  661 #ifdef MSDOSFS_DEBUG
  662         printf("msdosfs_write(vp %p, uio %p, ioflag %x, cred %p\n",
  663             vp, uio, ioflag, cred);
  664         printf("msdosfs_write(): diroff %lu, dirclust %lu, startcluster %lu\n",
  665             dep->de_diroffset, dep->de_dirclust, dep->de_StartCluster);
  666 #endif
  667 
  668         switch (vp->v_type) {
  669         case VREG:
  670                 if (ioflag & IO_APPEND)
  671                         uio->uio_offset = dep->de_FileSize;
  672                 thisvp = vp;
  673                 break;
  674         case VDIR:
  675                 return EISDIR;
  676         default:
  677                 panic("msdosfs_write(): bad file type");
  678         }
  679 
  680         /*
  681          * This is needed (unlike in ffs_write()) because we extend the
  682          * file outside of the loop but we don't want to extend the file
  683          * for writes of 0 bytes.
  684          */
  685         if (uio->uio_resid == 0)
  686                 return (0);
  687 
  688         /*
  689          * The caller is supposed to ensure that
  690          * uio->uio_offset >= 0 and uio->uio_resid >= 0.
  691          */
  692         if ((uoff_t)uio->uio_offset + uio->uio_resid > DOS_FILESIZE_MAX)
  693                 return (EFBIG);
  694 
  695         /*
  696          * If they've exceeded their filesize limit, tell them about it.
  697          */
  698         if (vn_rlimit_fsize(vp, uio, uio->uio_td))
  699                 return (EFBIG);
  700 
  701         /*
  702          * If the offset we are starting the write at is beyond the end of
  703          * the file, then they've done a seek.  Unix filesystems allow
  704          * files with holes in them, DOS doesn't so we must fill the hole
  705          * with zeroed blocks.
  706          */
  707         if (uio->uio_offset > dep->de_FileSize) {
  708                 error = deextend(dep, uio->uio_offset, cred);
  709                 if (error)
  710                         return (error);
  711         }
  712 
  713         /*
  714          * Remember some values in case the write fails.
  715          */
  716         resid = uio->uio_resid;
  717         osize = dep->de_FileSize;
  718 
  719         /*
  720          * If we write beyond the end of the file, extend it to its ultimate
  721          * size ahead of the time to hopefully get a contiguous area.
  722          */
  723         if (uio->uio_offset + resid > osize) {
  724                 count = de_clcount(pmp, uio->uio_offset + resid) -
  725                         de_clcount(pmp, osize);
  726                 error = extendfile(dep, count, NULL, NULL, 0);
  727                 if (error &&  (error != ENOSPC || (ioflag & IO_UNIT)))
  728                         goto errexit;
  729                 lastcn = dep->de_fc[FC_LASTFC].fc_frcn;
  730         } else
  731                 lastcn = de_clcount(pmp, osize) - 1;
  732 
  733         seqcount = ioflag >> IO_SEQSHIFT;
  734         do {
  735                 if (de_cluster(pmp, uio->uio_offset) > lastcn) {
  736                         error = ENOSPC;
  737                         break;
  738                 }
  739 
  740                 croffset = uio->uio_offset & pmp->pm_crbomask;
  741                 n = min(uio->uio_resid, pmp->pm_bpcluster - croffset);
  742                 if (uio->uio_offset + n > dep->de_FileSize) {
  743                         dep->de_FileSize = uio->uio_offset + n;
  744                         /* The object size needs to be set before buffer is allocated */
  745                         vnode_pager_setsize(vp, dep->de_FileSize);
  746                 }
  747 
  748                 bn = de_cluster(pmp, uio->uio_offset);
  749                 if ((uio->uio_offset & pmp->pm_crbomask) == 0
  750                     && (de_cluster(pmp, uio->uio_offset + uio->uio_resid)
  751                         > de_cluster(pmp, uio->uio_offset)
  752                         || uio->uio_offset + uio->uio_resid >= dep->de_FileSize)) {
  753                         /*
  754                          * If either the whole cluster gets written,
  755                          * or we write the cluster from its start beyond EOF,
  756                          * then no need to read data from disk.
  757                          */
  758                         bp = getblk(thisvp, bn, pmp->pm_bpcluster, 0, 0, 0);
  759                         vfs_bio_clrbuf(bp);
  760                         /*
  761                          * Do the bmap now, since pcbmap needs buffers
  762                          * for the fat table. (see msdosfs_strategy)
  763                          */
  764                         if (bp->b_blkno == bp->b_lblkno) {
  765                                 error = pcbmap(dep, bp->b_lblkno, &bn, 0, 0);
  766                                 if (error)
  767                                         bp->b_blkno = -1;
  768                                 else
  769                                         bp->b_blkno = bn;
  770                         }
  771                         if (bp->b_blkno == -1) {
  772                                 brelse(bp);
  773                                 if (!error)
  774                                         error = EIO;            /* XXX */
  775                                 break;
  776                         }
  777                 } else {
  778                         /*
  779                          * The block we need to write into exists, so read it in.
  780                          */
  781                         error = bread(thisvp, bn, pmp->pm_bpcluster, cred, &bp);
  782                         if (error) {
  783                                 brelse(bp);
  784                                 break;
  785                         }
  786                 }
  787 
  788                 /*
  789                  * Should these vnode_pager_* functions be done on dir
  790                  * files?
  791                  */
  792 
  793                 /*
  794                  * Copy the data from user space into the buf header.
  795                  */
  796                 error = uiomove(bp->b_data + croffset, n, uio);
  797                 if (error) {
  798                         brelse(bp);
  799                         break;
  800                 }
  801 
  802                 /* Prepare for clustered writes in some else clauses. */
  803                 if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0)
  804                         bp->b_flags |= B_CLUSTEROK;
  805 
  806                 /*
  807                  * If IO_SYNC, then each buffer is written synchronously.
  808                  * Otherwise, if we have a severe page deficiency then
  809                  * write the buffer asynchronously.  Otherwise, if on a
  810                  * cluster boundary then write the buffer asynchronously,
  811                  * combining it with contiguous clusters if permitted and
  812                  * possible, since we don't expect more writes into this
  813                  * buffer soon.  Otherwise, do a delayed write because we
  814                  * expect more writes into this buffer soon.
  815                  */
  816                 if (ioflag & IO_SYNC)
  817                         (void)bwrite(bp);
  818                 else if (vm_page_count_severe() || buf_dirty_count_severe())
  819                         bawrite(bp);
  820                 else if (n + croffset == pmp->pm_bpcluster) {
  821                         if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0)
  822                                 cluster_write(vp, bp, dep->de_FileSize,
  823                                     seqcount);
  824                         else
  825                                 bawrite(bp);
  826                 } else
  827                         bdwrite(bp);
  828                 dep->de_flag |= DE_UPDATE;
  829         } while (error == 0 && uio->uio_resid > 0);
  830 
  831         /*
  832          * If the write failed and they want us to, truncate the file back
  833          * to the size it was before the write was attempted.
  834          */
  835 errexit:
  836         if (error) {
  837                 if (ioflag & IO_UNIT) {
  838                         detrunc(dep, osize, ioflag & IO_SYNC, NOCRED, NULL);
  839                         uio->uio_offset -= resid - uio->uio_resid;
  840                         uio->uio_resid = resid;
  841                 } else {
  842                         detrunc(dep, dep->de_FileSize, ioflag & IO_SYNC, NOCRED, NULL);
  843                         if (uio->uio_resid != resid)
  844                                 error = 0;
  845                 }
  846         } else if (ioflag & IO_SYNC)
  847                 error = deupdat(dep, 1);
  848         return (error);
  849 }
  850 
  851 /*
  852  * Flush the blocks of a file to disk.
  853  *
  854  * This function is worthless for vnodes that represent directories. Maybe we
  855  * could just do a sync if they try an fsync on a directory file.
  856  */
  857 static int
  858 msdosfs_fsync(ap)
  859         struct vop_fsync_args /* {
  860                 struct vnode *a_vp;
  861                 struct ucred *a_cred;
  862                 int a_waitfor;
  863                 struct thread *a_td;
  864         } */ *ap;
  865 {
  866 
  867         vop_stdfsync(ap);
  868         return (deupdat(VTODE(ap->a_vp), ap->a_waitfor == MNT_WAIT));
  869 }
  870 
  871 static int
  872 msdosfs_remove(ap)
  873         struct vop_remove_args /* {
  874                 struct vnode *a_dvp;
  875                 struct vnode *a_vp;
  876                 struct componentname *a_cnp;
  877         } */ *ap;
  878 {
  879         struct denode *dep = VTODE(ap->a_vp);
  880         struct denode *ddep = VTODE(ap->a_dvp);
  881         int error;
  882 
  883         if (ap->a_vp->v_type == VDIR)
  884                 error = EPERM;
  885         else
  886                 error = removede(ddep, dep);
  887 #ifdef MSDOSFS_DEBUG
  888         printf("msdosfs_remove(), dep %p, v_usecount %d\n", dep, ap->a_vp->v_usecount);
  889 #endif
  890         return (error);
  891 }
  892 
  893 /*
  894  * DOS filesystems don't know what links are.
  895  */
  896 static int
  897 msdosfs_link(ap)
  898         struct vop_link_args /* {
  899                 struct vnode *a_tdvp;
  900                 struct vnode *a_vp;
  901                 struct componentname *a_cnp;
  902         } */ *ap;
  903 {
  904         return (EOPNOTSUPP);
  905 }
  906 
  907 /*
  908  * Renames on files require moving the denode to a new hash queue since the
  909  * denode's location is used to compute which hash queue to put the file
  910  * in. Unless it is a rename in place.  For example "mv a b".
  911  *
  912  * What follows is the basic algorithm:
  913  *
  914  * if (file move) {
  915  *      if (dest file exists) {
  916  *              remove dest file
  917  *      }
  918  *      if (dest and src in same directory) {
  919  *              rewrite name in existing directory slot
  920  *      } else {
  921  *              write new entry in dest directory
  922  *              update offset and dirclust in denode
  923  *              move denode to new hash chain
  924  *              clear old directory entry
  925  *      }
  926  * } else {
  927  *      directory move
  928  *      if (dest directory exists) {
  929  *              if (dest is not empty) {
  930  *                      return ENOTEMPTY
  931  *              }
  932  *              remove dest directory
  933  *      }
  934  *      if (dest and src in same directory) {
  935  *              rewrite name in existing entry
  936  *      } else {
  937  *              be sure dest is not a child of src directory
  938  *              write entry in dest directory
  939  *              update "." and ".." in moved directory
  940  *              clear old directory entry for moved directory
  941  *      }
  942  * }
  943  *
  944  * On entry:
  945  *      source's parent directory is unlocked
  946  *      source file or directory is unlocked
  947  *      destination's parent directory is locked
  948  *      destination file or directory is locked if it exists
  949  *
  950  * On exit:
  951  *      all denodes should be released
  952  */
  953 static int
  954 msdosfs_rename(ap)
  955         struct vop_rename_args /* {
  956                 struct vnode *a_fdvp;
  957                 struct vnode *a_fvp;
  958                 struct componentname *a_fcnp;
  959                 struct vnode *a_tdvp;
  960                 struct vnode *a_tvp;
  961                 struct componentname *a_tcnp;
  962         } */ *ap;
  963 {
  964         struct vnode *tdvp = ap->a_tdvp;
  965         struct vnode *fvp = ap->a_fvp;
  966         struct vnode *fdvp = ap->a_fdvp;
  967         struct vnode *tvp = ap->a_tvp;
  968         struct componentname *tcnp = ap->a_tcnp;
  969         struct componentname *fcnp = ap->a_fcnp;
  970         struct denode *ip, *xp, *dp, *zp;
  971         u_char toname[12], oldname[11];
  972         u_long from_diroffset, to_diroffset;
  973         u_char to_count;
  974         int doingdirectory = 0, newparent = 0;
  975         int error;
  976         u_long cn;
  977         daddr_t bn;
  978         struct denode *fddep;   /* from file's parent directory  */
  979         struct msdosfsmount *pmp;
  980         struct direntry *dotdotp;
  981         struct buf *bp;
  982 
  983         fddep = VTODE(ap->a_fdvp);
  984         pmp = fddep->de_pmp;
  985 
  986         pmp = VFSTOMSDOSFS(fdvp->v_mount);
  987 
  988 #ifdef DIAGNOSTIC
  989         if ((tcnp->cn_flags & HASBUF) == 0 ||
  990             (fcnp->cn_flags & HASBUF) == 0)
  991                 panic("msdosfs_rename: no name");
  992 #endif
  993         /*
  994          * Check for cross-device rename.
  995          */
  996         if (fvp->v_mount != tdvp->v_mount ||
  997             (tvp && fvp->v_mount != tvp->v_mount)) {
  998                 error = EXDEV;
  999 abortit:
 1000                 if (tdvp == tvp)
 1001                         vrele(tdvp);
 1002                 else
 1003                         vput(tdvp);
 1004                 if (tvp)
 1005                         vput(tvp);
 1006                 vrele(fdvp);
 1007                 vrele(fvp);
 1008                 return (error);
 1009         }
 1010 
 1011         /*
 1012          * If source and dest are the same, do nothing.
 1013          */
 1014         if (tvp == fvp) {
 1015                 error = 0;
 1016                 goto abortit;
 1017         }
 1018 
 1019         error = vn_lock(fvp, LK_EXCLUSIVE);
 1020         if (error)
 1021                 goto abortit;
 1022         dp = VTODE(fdvp);
 1023         ip = VTODE(fvp);
 1024 
 1025         /*
 1026          * Be sure we are not renaming ".", "..", or an alias of ".". This
 1027          * leads to a crippled directory tree.  It's pretty tough to do a
 1028          * "ls" or "pwd" with the "." directory entry missing, and "cd .."
 1029          * doesn't work if the ".." entry is missing.
 1030          */
 1031         if (ip->de_Attributes & ATTR_DIRECTORY) {
 1032                 /*
 1033                  * Avoid ".", "..", and aliases of "." for obvious reasons.
 1034                  */
 1035                 if ((fcnp->cn_namelen == 1 && fcnp->cn_nameptr[0] == '.') ||
 1036                     dp == ip ||
 1037                     (fcnp->cn_flags & ISDOTDOT) ||
 1038                     (tcnp->cn_flags & ISDOTDOT) ||
 1039                     (ip->de_flag & DE_RENAME)) {
 1040                         VOP_UNLOCK(fvp, 0);
 1041                         error = EINVAL;
 1042                         goto abortit;
 1043                 }
 1044                 ip->de_flag |= DE_RENAME;
 1045                 doingdirectory++;
 1046         }
 1047 
 1048         /*
 1049          * When the target exists, both the directory
 1050          * and target vnodes are returned locked.
 1051          */
 1052         dp = VTODE(tdvp);
 1053         xp = tvp ? VTODE(tvp) : NULL;
 1054         /*
 1055          * Remember direntry place to use for destination
 1056          */
 1057         to_diroffset = dp->de_fndoffset;
 1058         to_count = dp->de_fndcnt;
 1059 
 1060         /*
 1061          * If ".." must be changed (ie the directory gets a new
 1062          * parent) then the source directory must not be in the
 1063          * directory hierarchy above the target, as this would
 1064          * orphan everything below the source directory. Also
 1065          * the user must have write permission in the source so
 1066          * as to be able to change "..". We must repeat the call
 1067          * to namei, as the parent directory is unlocked by the
 1068          * call to doscheckpath().
 1069          */
 1070         error = VOP_ACCESS(fvp, VWRITE, tcnp->cn_cred, tcnp->cn_thread);
 1071         VOP_UNLOCK(fvp, 0);
 1072         if (VTODE(fdvp)->de_StartCluster != VTODE(tdvp)->de_StartCluster)
 1073                 newparent = 1;
 1074         if (doingdirectory && newparent) {
 1075                 if (error)      /* write access check above */
 1076                         goto bad;
 1077                 if (xp != NULL)
 1078                         vput(tvp);
 1079                 /*
 1080                  * doscheckpath() vput()'s dp,
 1081                  * so we have to do a relookup afterwards
 1082                  */
 1083                 error = doscheckpath(ip, dp);
 1084                 if (error)
 1085                         goto out;
 1086                 if ((tcnp->cn_flags & SAVESTART) == 0)
 1087                         panic("msdosfs_rename: lost to startdir");
 1088                 error = relookup(tdvp, &tvp, tcnp);
 1089                 if (error)
 1090                         goto out;
 1091                 dp = VTODE(tdvp);
 1092                 xp = tvp ? VTODE(tvp) : NULL;
 1093         }
 1094 
 1095         if (xp != NULL) {
 1096                 /*
 1097                  * Target must be empty if a directory and have no links
 1098                  * to it. Also, ensure source and target are compatible
 1099                  * (both directories, or both not directories).
 1100                  */
 1101                 if (xp->de_Attributes & ATTR_DIRECTORY) {
 1102                         if (!dosdirempty(xp)) {
 1103                                 error = ENOTEMPTY;
 1104                                 goto bad;
 1105                         }
 1106                         if (!doingdirectory) {
 1107                                 error = ENOTDIR;
 1108                                 goto bad;
 1109                         }
 1110                         cache_purge(tdvp);
 1111                 } else if (doingdirectory) {
 1112                         error = EISDIR;
 1113                         goto bad;
 1114                 }
 1115                 error = removede(dp, xp);
 1116                 if (error)
 1117                         goto bad;
 1118                 vput(tvp);
 1119                 xp = NULL;
 1120         }
 1121 
 1122         /*
 1123          * Convert the filename in tcnp into a dos filename. We copy this
 1124          * into the denode and directory entry for the destination
 1125          * file/directory.
 1126          */
 1127         error = uniqdosname(VTODE(tdvp), tcnp, toname);
 1128         if (error)
 1129                 goto abortit;
 1130 
 1131         /*
 1132          * Since from wasn't locked at various places above,
 1133          * have to do a relookup here.
 1134          */
 1135         fcnp->cn_flags &= ~MODMASK;
 1136         fcnp->cn_flags |= LOCKPARENT | LOCKLEAF;
 1137         if ((fcnp->cn_flags & SAVESTART) == 0)
 1138                 panic("msdosfs_rename: lost from startdir");
 1139         if (!newparent)
 1140                 VOP_UNLOCK(tdvp, 0);
 1141         if (relookup(fdvp, &fvp, fcnp) == 0)
 1142                 vrele(fdvp);
 1143         if (fvp == NULL) {
 1144                 /*
 1145                  * From name has disappeared.
 1146                  */
 1147                 if (doingdirectory)
 1148                         panic("rename: lost dir entry");
 1149                 if (newparent)
 1150                         VOP_UNLOCK(tdvp, 0);
 1151                 vrele(tdvp);
 1152                 vrele(ap->a_fvp);
 1153                 return 0;
 1154         }
 1155         xp = VTODE(fvp);
 1156         zp = VTODE(fdvp);
 1157         from_diroffset = zp->de_fndoffset;
 1158 
 1159         /*
 1160          * Ensure that the directory entry still exists and has not
 1161          * changed till now. If the source is a file the entry may
 1162          * have been unlinked or renamed. In either case there is
 1163          * no further work to be done. If the source is a directory
 1164          * then it cannot have been rmdir'ed or renamed; this is
 1165          * prohibited by the DE_RENAME flag.
 1166          */
 1167         if (xp != ip) {
 1168                 if (doingdirectory)
 1169                         panic("rename: lost dir entry");
 1170                 VOP_UNLOCK(fvp, 0);
 1171                 if (newparent)
 1172                         VOP_UNLOCK(fdvp, 0);
 1173                 vrele(ap->a_fvp);
 1174                 xp = NULL;
 1175         } else {
 1176                 vrele(fvp);
 1177                 xp = NULL;
 1178 
 1179                 /*
 1180                  * First write a new entry in the destination
 1181                  * directory and mark the entry in the source directory
 1182                  * as deleted.  Then move the denode to the correct hash
 1183                  * chain for its new location in the filesystem.  And, if
 1184                  * we moved a directory, then update its .. entry to point
 1185                  * to the new parent directory.
 1186                  */
 1187                 bcopy(ip->de_Name, oldname, 11);
 1188                 bcopy(toname, ip->de_Name, 11); /* update denode */
 1189                 dp->de_fndoffset = to_diroffset;
 1190                 dp->de_fndcnt = to_count;
 1191                 error = createde(ip, dp, (struct denode **)0, tcnp);
 1192                 if (error) {
 1193                         bcopy(oldname, ip->de_Name, 11);
 1194                         if (newparent)
 1195                                 VOP_UNLOCK(fdvp, 0);
 1196                         VOP_UNLOCK(fvp, 0);
 1197                         goto bad;
 1198                 }
 1199                 ip->de_refcnt++;
 1200                 zp->de_fndoffset = from_diroffset;
 1201                 error = removede(zp, ip);
 1202                 if (error) {
 1203                         /* XXX should downgrade to ro here, fs is corrupt */
 1204                         if (newparent)
 1205                                 VOP_UNLOCK(fdvp, 0);
 1206                         VOP_UNLOCK(fvp, 0);
 1207                         goto bad;
 1208                 }
 1209                 if (!doingdirectory) {
 1210                         error = pcbmap(dp, de_cluster(pmp, to_diroffset), 0,
 1211                                        &ip->de_dirclust, 0);
 1212                         if (error) {
 1213                                 /* XXX should downgrade to ro here, fs is corrupt */
 1214                                 if (newparent)
 1215                                         VOP_UNLOCK(fdvp, 0);
 1216                                 VOP_UNLOCK(fvp, 0);
 1217                                 goto bad;
 1218                         }
 1219                         if (ip->de_dirclust == MSDOSFSROOT)
 1220                                 ip->de_diroffset = to_diroffset;
 1221                         else
 1222                                 ip->de_diroffset = to_diroffset & pmp->pm_crbomask;
 1223                 }
 1224                 reinsert(ip);
 1225                 if (newparent)
 1226                         VOP_UNLOCK(fdvp, 0);
 1227         }
 1228 
 1229         /*
 1230          * If we moved a directory to a new parent directory, then we must
 1231          * fixup the ".." entry in the moved directory.
 1232          */
 1233         if (doingdirectory && newparent) {
 1234                 cn = ip->de_StartCluster;
 1235                 if (cn == MSDOSFSROOT) {
 1236                         /* this should never happen */
 1237                         panic("msdosfs_rename(): updating .. in root directory?");
 1238                 } else
 1239                         bn = cntobn(pmp, cn);
 1240                 error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster,
 1241                               NOCRED, &bp);
 1242                 if (error) {
 1243                         /* XXX should downgrade to ro here, fs is corrupt */
 1244                         brelse(bp);
 1245                         VOP_UNLOCK(fvp, 0);
 1246                         goto bad;
 1247                 }
 1248                 dotdotp = (struct direntry *)bp->b_data + 1;
 1249                 putushort(dotdotp->deStartCluster, dp->de_StartCluster);
 1250                 if (FAT32(pmp))
 1251                         putushort(dotdotp->deHighClust, dp->de_StartCluster >> 16);
 1252                 if (fvp->v_mount->mnt_flag & MNT_ASYNC)
 1253                         bdwrite(bp);
 1254                 else if ((error = bwrite(bp)) != 0) {
 1255                         /* XXX should downgrade to ro here, fs is corrupt */
 1256                         VOP_UNLOCK(fvp, 0);
 1257                         goto bad;
 1258                 }
 1259         }
 1260 
 1261         /*
 1262          * The msdosfs lookup is case insensitive. Several aliases may
 1263          * be inserted for a single directory entry. As a consequnce,
 1264          * name cache purge done by lookup for fvp when DELETE op for
 1265          * namei is specified, might be not enough to expunge all
 1266          * namecache entries that were installed for this direntry.
 1267          */
 1268         cache_purge(fvp);
 1269         VOP_UNLOCK(fvp, 0);
 1270 bad:
 1271         if (xp)
 1272                 vput(tvp);
 1273         vput(tdvp);
 1274 out:
 1275         ip->de_flag &= ~DE_RENAME;
 1276         vrele(fdvp);
 1277         vrele(fvp);
 1278         return (error);
 1279 
 1280 }
 1281 
 1282 static struct {
 1283         struct direntry dot;
 1284         struct direntry dotdot;
 1285 } dosdirtemplate = {
 1286         {       ".          ",                          /* the . entry */
 1287                 ATTR_DIRECTORY,                         /* file attribute */
 1288                 0,                                      /* reserved */
 1289                 0, { 0, 0 }, { 0, 0 },                  /* create time & date */
 1290                 { 0, 0 },                               /* access date */
 1291                 { 0, 0 },                               /* high bits of start cluster */
 1292                 { 210, 4 }, { 210, 4 },                 /* modify time & date */
 1293                 { 0, 0 },                               /* startcluster */
 1294                 { 0, 0, 0, 0 }                          /* filesize */
 1295         },
 1296         {       "..         ",                          /* the .. entry */
 1297                 ATTR_DIRECTORY,                         /* file attribute */
 1298                 0,                                      /* reserved */
 1299                 0, { 0, 0 }, { 0, 0 },                  /* create time & date */
 1300                 { 0, 0 },                               /* access date */
 1301                 { 0, 0 },                               /* high bits of start cluster */
 1302                 { 210, 4 }, { 210, 4 },                 /* modify time & date */
 1303                 { 0, 0 },                               /* startcluster */
 1304                 { 0, 0, 0, 0 }                          /* filesize */
 1305         }
 1306 };
 1307 
 1308 static int
 1309 msdosfs_mkdir(ap)
 1310         struct vop_mkdir_args /* {
 1311                 struct vnode *a_dvp;
 1312                 struct vnode **a_vpp;
 1313                 struvt componentname *a_cnp;
 1314                 struct vattr *a_vap;
 1315         } */ *ap;
 1316 {
 1317         struct componentname *cnp = ap->a_cnp;
 1318         struct denode *dep;
 1319         struct denode *pdep = VTODE(ap->a_dvp);
 1320         struct direntry *denp;
 1321         struct msdosfsmount *pmp = pdep->de_pmp;
 1322         struct buf *bp;
 1323         u_long newcluster, pcl;
 1324         int bn;
 1325         int error;
 1326         struct denode ndirent;
 1327         struct timespec ts;
 1328 
 1329         /*
 1330          * If this is the root directory and there is no space left we
 1331          * can't do anything.  This is because the root directory can not
 1332          * change size.
 1333          */
 1334         if (pdep->de_StartCluster == MSDOSFSROOT
 1335             && pdep->de_fndoffset >= pdep->de_FileSize) {
 1336                 error = ENOSPC;
 1337                 goto bad2;
 1338         }
 1339 
 1340         /*
 1341          * Allocate a cluster to hold the about to be created directory.
 1342          */
 1343         error = clusteralloc(pmp, 0, 1, CLUST_EOFE, &newcluster, NULL);
 1344         if (error)
 1345                 goto bad2;
 1346 
 1347         bzero(&ndirent, sizeof(ndirent));
 1348         ndirent.de_pmp = pmp;
 1349         ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE;
 1350         getnanotime(&ts);
 1351         DETIMES(&ndirent, &ts, &ts, &ts);
 1352 
 1353         /*
 1354          * Now fill the cluster with the "." and ".." entries. And write
 1355          * the cluster to disk.  This way it is there for the parent
 1356          * directory to be pointing at if there were a crash.
 1357          */
 1358         bn = cntobn(pmp, newcluster);
 1359         /* always succeeds */
 1360         bp = getblk(pmp->pm_devvp, bn, pmp->pm_bpcluster, 0, 0, 0);
 1361         bzero(bp->b_data, pmp->pm_bpcluster);
 1362         bcopy(&dosdirtemplate, bp->b_data, sizeof dosdirtemplate);
 1363         denp = (struct direntry *)bp->b_data;
 1364         putushort(denp[0].deStartCluster, newcluster);
 1365         putushort(denp[0].deCDate, ndirent.de_CDate);
 1366         putushort(denp[0].deCTime, ndirent.de_CTime);
 1367         denp[0].deCHundredth = ndirent.de_CHun;
 1368         putushort(denp[0].deADate, ndirent.de_ADate);
 1369         putushort(denp[0].deMDate, ndirent.de_MDate);
 1370         putushort(denp[0].deMTime, ndirent.de_MTime);
 1371         pcl = pdep->de_StartCluster;
 1372         if (FAT32(pmp) && pcl == pmp->pm_rootdirblk)
 1373                 pcl = 0;
 1374         putushort(denp[1].deStartCluster, pcl);
 1375         putushort(denp[1].deCDate, ndirent.de_CDate);
 1376         putushort(denp[1].deCTime, ndirent.de_CTime);
 1377         denp[1].deCHundredth = ndirent.de_CHun;
 1378         putushort(denp[1].deADate, ndirent.de_ADate);
 1379         putushort(denp[1].deMDate, ndirent.de_MDate);
 1380         putushort(denp[1].deMTime, ndirent.de_MTime);
 1381         if (FAT32(pmp)) {
 1382                 putushort(denp[0].deHighClust, newcluster >> 16);
 1383                 putushort(denp[1].deHighClust, pdep->de_StartCluster >> 16);
 1384         }
 1385 
 1386         if (ap->a_dvp->v_mount->mnt_flag & MNT_ASYNC)
 1387                 bdwrite(bp);
 1388         else if ((error = bwrite(bp)) != 0)
 1389                 goto bad;
 1390 
 1391         /*
 1392          * Now build up a directory entry pointing to the newly allocated
 1393          * cluster.  This will be written to an empty slot in the parent
 1394          * directory.
 1395          */
 1396 #ifdef DIAGNOSTIC
 1397         if ((cnp->cn_flags & HASBUF) == 0)
 1398                 panic("msdosfs_mkdir: no name");
 1399 #endif
 1400         error = uniqdosname(pdep, cnp, ndirent.de_Name);
 1401         if (error)
 1402                 goto bad;
 1403 
 1404         ndirent.de_Attributes = ATTR_DIRECTORY;
 1405         ndirent.de_LowerCase = 0;
 1406         ndirent.de_StartCluster = newcluster;
 1407         ndirent.de_FileSize = 0;
 1408         error = createde(&ndirent, pdep, &dep, cnp);
 1409         if (error)
 1410                 goto bad;
 1411         *ap->a_vpp = DETOV(dep);
 1412         return (0);
 1413 
 1414 bad:
 1415         clusterfree(pmp, newcluster, NULL);
 1416 bad2:
 1417         return (error);
 1418 }
 1419 
 1420 static int
 1421 msdosfs_rmdir(ap)
 1422         struct vop_rmdir_args /* {
 1423                 struct vnode *a_dvp;
 1424                 struct vnode *a_vp;
 1425                 struct componentname *a_cnp;
 1426         } */ *ap;
 1427 {
 1428         struct vnode *vp = ap->a_vp;
 1429         struct vnode *dvp = ap->a_dvp;
 1430         struct componentname *cnp = ap->a_cnp;
 1431         struct denode *ip, *dp;
 1432         struct thread *td = cnp->cn_thread;
 1433         int error;
 1434 
 1435         ip = VTODE(vp);
 1436         dp = VTODE(dvp);
 1437 
 1438         /*
 1439          * Verify the directory is empty (and valid).
 1440          * (Rmdir ".." won't be valid since
 1441          *  ".." will contain a reference to
 1442          *  the current directory and thus be
 1443          *  non-empty.)
 1444          */
 1445         error = 0;
 1446         if (!dosdirempty(ip) || ip->de_flag & DE_RENAME) {
 1447                 error = ENOTEMPTY;
 1448                 goto out;
 1449         }
 1450         /*
 1451          * Delete the entry from the directory.  For dos filesystems this
 1452          * gets rid of the directory entry on disk, the in memory copy
 1453          * still exists but the de_refcnt is <= 0.  This prevents it from
 1454          * being found by deget().  When the vput() on dep is done we give
 1455          * up access and eventually msdosfs_reclaim() will be called which
 1456          * will remove it from the denode cache.
 1457          */
 1458         error = removede(dp, ip);
 1459         if (error)
 1460                 goto out;
 1461         /*
 1462          * This is where we decrement the link count in the parent
 1463          * directory.  Since dos filesystems don't do this we just purge
 1464          * the name cache.
 1465          */
 1466         cache_purge(dvp);
 1467         /*
 1468          * Truncate the directory that is being deleted.
 1469          */
 1470         error = detrunc(ip, (u_long)0, IO_SYNC, cnp->cn_cred, td);
 1471         cache_purge(vp);
 1472 
 1473 out:
 1474         return (error);
 1475 }
 1476 
 1477 /*
 1478  * DOS filesystems don't know what symlinks are.
 1479  */
 1480 static int
 1481 msdosfs_symlink(ap)
 1482         struct vop_symlink_args /* {
 1483                 struct vnode *a_dvp;
 1484                 struct vnode **a_vpp;
 1485                 struct componentname *a_cnp;
 1486                 struct vattr *a_vap;
 1487                 char *a_target;
 1488         } */ *ap;
 1489 {
 1490         return (EOPNOTSUPP);
 1491 }
 1492 
 1493 static int
 1494 msdosfs_readdir(ap)
 1495         struct vop_readdir_args /* {
 1496                 struct vnode *a_vp;
 1497                 struct uio *a_uio;
 1498                 struct ucred *a_cred;
 1499                 int *a_eofflag;
 1500                 int *a_ncookies;
 1501                 u_long **a_cookies;
 1502         } */ *ap;
 1503 {
 1504         struct mbnambuf nb;
 1505         int error = 0;
 1506         int diff;
 1507         long n;
 1508         int blsize;
 1509         long on;
 1510         u_long cn;
 1511         uint64_t fileno;
 1512         u_long dirsperblk;
 1513         long bias = 0;
 1514         daddr_t bn, lbn;
 1515         struct buf *bp;
 1516         struct denode *dep = VTODE(ap->a_vp);
 1517         struct msdosfsmount *pmp = dep->de_pmp;
 1518         struct direntry *dentp;
 1519         struct dirent dirbuf;
 1520         struct uio *uio = ap->a_uio;
 1521         u_long *cookies = NULL;
 1522         int ncookies = 0;
 1523         off_t offset, off;
 1524         int chksum = -1;
 1525 
 1526 #ifdef MSDOSFS_DEBUG
 1527         printf("msdosfs_readdir(): vp %p, uio %p, cred %p, eofflagp %p\n",
 1528             ap->a_vp, uio, ap->a_cred, ap->a_eofflag);
 1529 #endif
 1530 
 1531         /*
 1532          * msdosfs_readdir() won't operate properly on regular files since
 1533          * it does i/o only with the filesystem vnode, and hence can
 1534          * retrieve the wrong block from the buffer cache for a plain file.
 1535          * So, fail attempts to readdir() on a plain file.
 1536          */
 1537         if ((dep->de_Attributes & ATTR_DIRECTORY) == 0)
 1538                 return (ENOTDIR);
 1539 
 1540         /*
 1541          * To be safe, initialize dirbuf
 1542          */
 1543         bzero(dirbuf.d_name, sizeof(dirbuf.d_name));
 1544 
 1545         /*
 1546          * If the user buffer is smaller than the size of one dos directory
 1547          * entry or the file offset is not a multiple of the size of a
 1548          * directory entry, then we fail the read.
 1549          */
 1550         off = offset = uio->uio_offset;
 1551         if (uio->uio_resid < sizeof(struct direntry) ||
 1552             (offset & (sizeof(struct direntry) - 1)))
 1553                 return (EINVAL);
 1554 
 1555         if (ap->a_ncookies) {
 1556                 ncookies = uio->uio_resid / 16;
 1557                 cookies = malloc(ncookies * sizeof(u_long), M_TEMP,
 1558                        M_WAITOK);
 1559                 *ap->a_cookies = cookies;
 1560                 *ap->a_ncookies = ncookies;
 1561         }
 1562 
 1563         dirsperblk = pmp->pm_BytesPerSec / sizeof(struct direntry);
 1564 
 1565         /*
 1566          * If they are reading from the root directory then, we simulate
 1567          * the . and .. entries since these don't exist in the root
 1568          * directory.  We also set the offset bias to make up for having to
 1569          * simulate these entries. By this I mean that at file offset 64 we
 1570          * read the first entry in the root directory that lives on disk.
 1571          */
 1572         if (dep->de_StartCluster == MSDOSFSROOT
 1573             || (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk)) {
 1574 #if 0
 1575                 printf("msdosfs_readdir(): going after . or .. in root dir, offset %d\n",
 1576                     offset);
 1577 #endif
 1578                 bias = 2 * sizeof(struct direntry);
 1579                 if (offset < bias) {
 1580                         for (n = (int)offset / sizeof(struct direntry);
 1581                              n < 2; n++) {
 1582                                 if (FAT32(pmp))
 1583                                         fileno = (uint64_t)cntobn(pmp,
 1584                                                                  pmp->pm_rootdirblk)
 1585                                                           * dirsperblk;
 1586                                 else
 1587                                         fileno = 1;
 1588                                 if (pmp->pm_flags & MSDOSFS_LARGEFS) {
 1589                                         dirbuf.d_fileno =
 1590                                             msdosfs_fileno_map(pmp->pm_mountp,
 1591                                             fileno);
 1592                                 } else {
 1593 
 1594                                         dirbuf.d_fileno = (uint32_t)fileno;
 1595                                 }
 1596                                 dirbuf.d_type = DT_DIR;
 1597                                 switch (n) {
 1598                                 case 0:
 1599                                         dirbuf.d_namlen = 1;
 1600                                         strcpy(dirbuf.d_name, ".");
 1601                                         break;
 1602                                 case 1:
 1603                                         dirbuf.d_namlen = 2;
 1604                                         strcpy(dirbuf.d_name, "..");
 1605                                         break;
 1606                                 }
 1607                                 dirbuf.d_reclen = GENERIC_DIRSIZ(&dirbuf);
 1608                                 if (uio->uio_resid < dirbuf.d_reclen)
 1609                                         goto out;
 1610                                 error = uiomove(&dirbuf, dirbuf.d_reclen, uio);
 1611                                 if (error)
 1612                                         goto out;
 1613                                 offset += sizeof(struct direntry);
 1614                                 off = offset;
 1615                                 if (cookies) {
 1616                                         *cookies++ = offset;
 1617                                         if (--ncookies <= 0)
 1618                                                 goto out;
 1619                                 }
 1620                         }
 1621                 }
 1622         }
 1623 
 1624         mbnambuf_init(&nb);
 1625         off = offset;
 1626         while (uio->uio_resid > 0) {
 1627                 lbn = de_cluster(pmp, offset - bias);
 1628                 on = (offset - bias) & pmp->pm_crbomask;
 1629                 n = min(pmp->pm_bpcluster - on, uio->uio_resid);
 1630                 diff = dep->de_FileSize - (offset - bias);
 1631                 if (diff <= 0)
 1632                         break;
 1633                 n = min(n, diff);
 1634                 error = pcbmap(dep, lbn, &bn, &cn, &blsize);
 1635                 if (error)
 1636                         break;
 1637                 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
 1638                 if (error) {
 1639                         brelse(bp);
 1640                         return (error);
 1641                 }
 1642                 n = min(n, blsize - bp->b_resid);
 1643                 if (n == 0) {
 1644                         brelse(bp);
 1645                         return (EIO);
 1646                 }
 1647 
 1648                 /*
 1649                  * Convert from dos directory entries to fs-independent
 1650                  * directory entries.
 1651                  */
 1652                 for (dentp = (struct direntry *)(bp->b_data + on);
 1653                      (char *)dentp < bp->b_data + on + n;
 1654                      dentp++, offset += sizeof(struct direntry)) {
 1655 #if 0
 1656                         printf("rd: dentp %08x prev %08x crnt %08x deName %02x attr %02x\n",
 1657                             dentp, prev, crnt, dentp->deName[0], dentp->deAttributes);
 1658 #endif
 1659                         /*
 1660                          * If this is an unused entry, we can stop.
 1661                          */
 1662                         if (dentp->deName[0] == SLOT_EMPTY) {
 1663                                 brelse(bp);
 1664                                 goto out;
 1665                         }
 1666                         /*
 1667                          * Skip deleted entries.
 1668                          */
 1669                         if (dentp->deName[0] == SLOT_DELETED) {
 1670                                 chksum = -1;
 1671                                 mbnambuf_init(&nb);
 1672                                 continue;
 1673                         }
 1674 
 1675                         /*
 1676                          * Handle Win95 long directory entries
 1677                          */
 1678                         if (dentp->deAttributes == ATTR_WIN95) {
 1679                                 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
 1680                                         continue;
 1681                                 chksum = win2unixfn(&nb,
 1682                                     (struct winentry *)dentp, chksum, pmp);
 1683                                 continue;
 1684                         }
 1685 
 1686                         /*
 1687                          * Skip volume labels
 1688                          */
 1689                         if (dentp->deAttributes & ATTR_VOLUME) {
 1690                                 chksum = -1;
 1691                                 mbnambuf_init(&nb);
 1692                                 continue;
 1693                         }
 1694                         /*
 1695                          * This computation of d_fileno must match
 1696                          * the computation of va_fileid in
 1697                          * msdosfs_getattr.
 1698                          */
 1699                         if (dentp->deAttributes & ATTR_DIRECTORY) {
 1700                                 fileno = getushort(dentp->deStartCluster);
 1701                                 if (FAT32(pmp))
 1702                                         fileno |= getushort(dentp->deHighClust) << 16;
 1703                                 /* if this is the root directory */
 1704                                 if (fileno == MSDOSFSROOT)
 1705                                         if (FAT32(pmp))
 1706                                                 fileno = (uint64_t)cntobn(pmp,
 1707                                                                 pmp->pm_rootdirblk)
 1708                                                          * dirsperblk;
 1709                                         else
 1710                                                 fileno = 1;
 1711                                 else
 1712                                         fileno = (uint64_t)cntobn(pmp, fileno) *
 1713                                             dirsperblk;
 1714                                 dirbuf.d_type = DT_DIR;
 1715                         } else {
 1716                                 fileno = (uoff_t)offset /
 1717                                     sizeof(struct direntry);
 1718                                 dirbuf.d_type = DT_REG;
 1719                         }
 1720                         if (pmp->pm_flags & MSDOSFS_LARGEFS) {
 1721                                 dirbuf.d_fileno =
 1722                                     msdosfs_fileno_map(pmp->pm_mountp, fileno);
 1723                         } else
 1724                                 dirbuf.d_fileno = (uint32_t)fileno;
 1725 
 1726                         if (chksum != winChksum(dentp->deName)) {
 1727                                 dirbuf.d_namlen = dos2unixfn(dentp->deName,
 1728                                     (u_char *)dirbuf.d_name,
 1729                                     dentp->deLowerCase |
 1730                                         ((pmp->pm_flags & MSDOSFSMNT_SHORTNAME) ?
 1731                                         (LCASE_BASE | LCASE_EXT) : 0),
 1732                                     pmp);
 1733                                 mbnambuf_init(&nb);
 1734                         } else
 1735                                 mbnambuf_flush(&nb, &dirbuf);
 1736                         chksum = -1;
 1737                         dirbuf.d_reclen = GENERIC_DIRSIZ(&dirbuf);
 1738                         if (uio->uio_resid < dirbuf.d_reclen) {
 1739                                 brelse(bp);
 1740                                 goto out;
 1741                         }
 1742                         error = uiomove(&dirbuf, dirbuf.d_reclen, uio);
 1743                         if (error) {
 1744                                 brelse(bp);
 1745                                 goto out;
 1746                         }
 1747                         if (cookies) {
 1748                                 *cookies++ = offset + sizeof(struct direntry);
 1749                                 if (--ncookies <= 0) {
 1750                                         brelse(bp);
 1751                                         goto out;
 1752                                 }
 1753                         }
 1754                         off = offset + sizeof(struct direntry);
 1755                 }
 1756                 brelse(bp);
 1757         }
 1758 out:
 1759         /* Subtract unused cookies */
 1760         if (ap->a_ncookies)
 1761                 *ap->a_ncookies -= ncookies;
 1762 
 1763         uio->uio_offset = off;
 1764 
 1765         /*
 1766          * Set the eofflag (NFS uses it)
 1767          */
 1768         if (ap->a_eofflag) {
 1769                 if (dep->de_FileSize - (offset - bias) <= 0)
 1770                         *ap->a_eofflag = 1;
 1771                 else
 1772                         *ap->a_eofflag = 0;
 1773         }
 1774         return (error);
 1775 }
 1776 
 1777 /*-
 1778  * a_vp   - pointer to the file's vnode
 1779  * a_bn   - logical block number within the file (cluster number for us)
 1780  * a_bop  - where to return the bufobj of the special file containing the fs
 1781  * a_bnp  - where to return the "physical" block number corresponding to a_bn
 1782  *          (relative to the special file; units are blocks of size DEV_BSIZE)
 1783  * a_runp - where to return the "run past" a_bn.  This is the count of logical
 1784  *          blocks whose physical blocks (together with a_bn's physical block)
 1785  *          are contiguous.
 1786  * a_runb - where to return the "run before" a_bn.
 1787  */
 1788 static int
 1789 msdosfs_bmap(ap)
 1790         struct vop_bmap_args /* {
 1791                 struct vnode *a_vp;
 1792                 daddr_t a_bn;
 1793                 struct bufobj **a_bop;
 1794                 daddr_t *a_bnp;
 1795                 int *a_runp;
 1796                 int *a_runb;
 1797         } */ *ap;
 1798 {
 1799         struct denode *dep;
 1800         struct mount *mp;
 1801         struct msdosfsmount *pmp;
 1802         struct vnode *vp;
 1803         daddr_t runbn;
 1804         u_long cn;
 1805         int bnpercn, error, maxio, maxrun, run;
 1806 
 1807         vp = ap->a_vp;
 1808         dep = VTODE(vp);
 1809         pmp = dep->de_pmp;
 1810         if (ap->a_bop != NULL)
 1811                 *ap->a_bop = &pmp->pm_devvp->v_bufobj;
 1812         if (ap->a_bnp == NULL)
 1813                 return (0);
 1814         if (ap->a_runp != NULL)
 1815                 *ap->a_runp = 0;
 1816         if (ap->a_runb != NULL)
 1817                 *ap->a_runb = 0;
 1818         cn = ap->a_bn;
 1819         if (cn != ap->a_bn)
 1820                 return (EFBIG);
 1821         error = pcbmap(dep, cn, ap->a_bnp, NULL, NULL);
 1822         if (error != 0 || (ap->a_runp == NULL && ap->a_runb == NULL))
 1823                 return (error);
 1824 
 1825         mp = vp->v_mount;
 1826         maxio = mp->mnt_iosize_max / mp->mnt_stat.f_iosize;
 1827         bnpercn = de_cn2bn(pmp, 1);
 1828         if (ap->a_runp != NULL) {
 1829                 maxrun = ulmin(maxio - 1, pmp->pm_maxcluster - cn);
 1830                 for (run = 1; run <= maxrun; run++) {
 1831                         if (pcbmap(dep, cn + run, &runbn, NULL, NULL) != 0 ||
 1832                             runbn != *ap->a_bnp + run * bnpercn)
 1833                                 break;
 1834                 }
 1835                 *ap->a_runp = run - 1;
 1836         }
 1837         if (ap->a_runb != NULL) {
 1838                 maxrun = ulmin(maxio - 1, cn);
 1839                 for (run = 1; run < maxrun; run++) {
 1840                         if (pcbmap(dep, cn - run, &runbn, NULL, NULL) != 0 ||
 1841                             runbn != *ap->a_bnp - run * bnpercn)
 1842                                 break;
 1843                 }
 1844                 *ap->a_runb = run - 1;
 1845         }
 1846         return (0);
 1847 }
 1848 
 1849 static int
 1850 msdosfs_strategy(ap)
 1851         struct vop_strategy_args /* {
 1852                 struct vnode *a_vp;
 1853                 struct buf *a_bp;
 1854         } */ *ap;
 1855 {
 1856         struct buf *bp = ap->a_bp;
 1857         struct denode *dep = VTODE(ap->a_vp);
 1858         struct bufobj *bo;
 1859         int error = 0;
 1860         daddr_t blkno;
 1861 
 1862         /*
 1863          * If we don't already know the filesystem relative block number
 1864          * then get it using pcbmap().  If pcbmap() returns the block
 1865          * number as -1 then we've got a hole in the file.  DOS filesystems
 1866          * don't allow files with holes, so we shouldn't ever see this.
 1867          */
 1868         if (bp->b_blkno == bp->b_lblkno) {
 1869                 error = pcbmap(dep, bp->b_lblkno, &blkno, 0, 0);
 1870                 bp->b_blkno = blkno;
 1871                 if (error) {
 1872                         bp->b_error = error;
 1873                         bp->b_ioflags |= BIO_ERROR;
 1874                         bufdone(bp);
 1875                         return (0);
 1876                 }
 1877                 if ((long)bp->b_blkno == -1)
 1878                         vfs_bio_clrbuf(bp);
 1879         }
 1880         if (bp->b_blkno == -1) {
 1881                 bufdone(bp);
 1882                 return (0);
 1883         }
 1884         /*
 1885          * Read/write the block from/to the disk that contains the desired
 1886          * file block.
 1887          */
 1888         bp->b_iooffset = dbtob(bp->b_blkno);
 1889         bo = dep->de_pmp->pm_bo;
 1890         BO_STRATEGY(bo, bp);
 1891         return (0);
 1892 }
 1893 
 1894 static int
 1895 msdosfs_print(ap)
 1896         struct vop_print_args /* {
 1897                 struct vnode *vp;
 1898         } */ *ap;
 1899 {
 1900         struct denode *dep = VTODE(ap->a_vp);
 1901 
 1902         printf("\tstartcluster %lu, dircluster %lu, diroffset %lu, ",
 1903                dep->de_StartCluster, dep->de_dirclust, dep->de_diroffset);
 1904         printf("on dev %s\n", devtoname(dep->de_pmp->pm_dev));
 1905         return (0);
 1906 }
 1907 
 1908 static int
 1909 msdosfs_pathconf(ap)
 1910         struct vop_pathconf_args /* {
 1911                 struct vnode *a_vp;
 1912                 int a_name;
 1913                 int *a_retval;
 1914         } */ *ap;
 1915 {
 1916         struct msdosfsmount *pmp = VTODE(ap->a_vp)->de_pmp;
 1917 
 1918         switch (ap->a_name) {
 1919         case _PC_LINK_MAX:
 1920                 *ap->a_retval = 1;
 1921                 return (0);
 1922         case _PC_NAME_MAX:
 1923                 *ap->a_retval = pmp->pm_flags & MSDOSFSMNT_LONGNAME ? WIN_MAXLEN : 12;
 1924                 return (0);
 1925         case _PC_PATH_MAX:
 1926                 *ap->a_retval = PATH_MAX;
 1927                 return (0);
 1928         case _PC_CHOWN_RESTRICTED:
 1929                 *ap->a_retval = 1;
 1930                 return (0);
 1931         case _PC_NO_TRUNC:
 1932                 *ap->a_retval = 0;
 1933                 return (0);
 1934         default:
 1935                 return (EINVAL);
 1936         }
 1937         /* NOTREACHED */
 1938 }
 1939 
 1940 static int
 1941 msdosfs_vptofh(ap)
 1942         struct vop_vptofh_args /* {
 1943                 struct vnode *a_vp;
 1944                 struct fid *a_fhp;
 1945         } */ *ap;
 1946 {
 1947         struct denode *dep;
 1948         struct defid *defhp;
 1949 
 1950         dep = VTODE(ap->a_vp);
 1951         defhp = (struct defid *)ap->a_fhp;
 1952         defhp->defid_len = sizeof(struct defid);
 1953         defhp->defid_dirclust = dep->de_dirclust;
 1954         defhp->defid_dirofs = dep->de_diroffset;
 1955         /* defhp->defid_gen = dep->de_gen; */
 1956         return (0);
 1957 }
 1958 
 1959 /* Global vfs data structures for msdosfs */
 1960 struct vop_vector msdosfs_vnodeops = {
 1961         .vop_default =          &default_vnodeops,
 1962 
 1963         .vop_access =           msdosfs_access,
 1964         .vop_bmap =             msdosfs_bmap,
 1965         .vop_cachedlookup =     msdosfs_lookup,
 1966         .vop_open =             msdosfs_open,
 1967         .vop_close =            msdosfs_close,
 1968         .vop_create =           msdosfs_create,
 1969         .vop_fsync =            msdosfs_fsync,
 1970         .vop_getattr =          msdosfs_getattr,
 1971         .vop_inactive =         msdosfs_inactive,
 1972         .vop_link =             msdosfs_link,
 1973         .vop_lookup =           vfs_cache_lookup,
 1974         .vop_mkdir =            msdosfs_mkdir,
 1975         .vop_mknod =            msdosfs_mknod,
 1976         .vop_pathconf =         msdosfs_pathconf,
 1977         .vop_print =            msdosfs_print,
 1978         .vop_read =             msdosfs_read,
 1979         .vop_readdir =          msdosfs_readdir,
 1980         .vop_reclaim =          msdosfs_reclaim,
 1981         .vop_remove =           msdosfs_remove,
 1982         .vop_rename =           msdosfs_rename,
 1983         .vop_rmdir =            msdosfs_rmdir,
 1984         .vop_setattr =          msdosfs_setattr,
 1985         .vop_strategy =         msdosfs_strategy,
 1986         .vop_symlink =          msdosfs_symlink,
 1987         .vop_write =            msdosfs_write,
 1988         .vop_vptofh =           msdosfs_vptofh,
 1989 };

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