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 /* $FreeBSD$ */
    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/proc.h>
   65 #include <sys/resourcevar.h>
   66 #include <sys/signalvar.h>
   67 #include <sys/stat.h>
   68 #include <sys/unistd.h>
   69 #include <sys/vnode.h>
   70 
   71 #include <vm/vm.h>
   72 #include <vm/vm_extern.h>
   73 
   74 #include <fs/msdosfs/bpb.h>
   75 #include <fs/msdosfs/direntry.h>
   76 #include <fs/msdosfs/denode.h>
   77 #include <fs/msdosfs/fat.h>
   78 #include <fs/msdosfs/msdosfsmount.h>
   79 
   80 #define DOS_FILESIZE_MAX        0xffffffff
   81 
   82 /*
   83  * Prototypes for MSDOSFS vnode operations
   84  */
   85 static vop_create_t     msdosfs_create;
   86 static vop_mknod_t      msdosfs_mknod;
   87 static vop_open_t       msdosfs_open;
   88 static vop_close_t      msdosfs_close;
   89 static vop_access_t     msdosfs_access;
   90 static vop_getattr_t    msdosfs_getattr;
   91 static vop_setattr_t    msdosfs_setattr;
   92 static vop_read_t       msdosfs_read;
   93 static vop_write_t      msdosfs_write;
   94 static vop_fsync_t      msdosfs_fsync;
   95 static vop_remove_t     msdosfs_remove;
   96 static vop_link_t       msdosfs_link;
   97 static vop_rename_t     msdosfs_rename;
   98 static vop_mkdir_t      msdosfs_mkdir;
   99 static vop_rmdir_t      msdosfs_rmdir;
  100 static vop_symlink_t    msdosfs_symlink;
  101 static vop_readdir_t    msdosfs_readdir;
  102 static vop_bmap_t       msdosfs_bmap;
  103 static vop_strategy_t   msdosfs_strategy;
  104 static vop_print_t      msdosfs_print;
  105 static vop_pathconf_t   msdosfs_pathconf;
  106 static vop_vptofh_t     msdosfs_vptofh;
  107 
  108 /*
  109  * Some general notes:
  110  *
  111  * In the ufs filesystem the inodes, superblocks, and indirect blocks are
  112  * read/written using the vnode for the filesystem. Blocks that represent
  113  * the contents of a file are read/written using the vnode for the file
  114  * (including directories when they are read/written as files). This
  115  * presents problems for the dos filesystem because data that should be in
  116  * an inode (if dos had them) resides in the directory itself.  Since we
  117  * must update directory entries without the benefit of having the vnode
  118  * for the directory we must use the vnode for the filesystem.  This means
  119  * that when a directory is actually read/written (via read, write, or
  120  * readdir, or seek) we must use the vnode for the filesystem instead of
  121  * the vnode for the directory as would happen in ufs. This is to insure we
  122  * retreive the correct block from the buffer cache since the hash value is
  123  * based upon the vnode address and the desired block number.
  124  */
  125 
  126 /*
  127  * Create a regular file. On entry the directory to contain the file being
  128  * created is locked.  We must release before we return. We must also free
  129  * the pathname buffer pointed at by cnp->cn_pnbuf, always on error, or
  130  * only if the SAVESTART bit in cn_flags is clear on success.
  131  */
  132 static int
  133 msdosfs_create(ap)
  134         struct vop_create_args /* {
  135                 struct vnode *a_dvp;
  136                 struct vnode **a_vpp;
  137                 struct componentname *a_cnp;
  138                 struct vattr *a_vap;
  139         } */ *ap;
  140 {
  141         struct componentname *cnp = ap->a_cnp;
  142         struct denode ndirent;
  143         struct denode *dep;
  144         struct denode *pdep = VTODE(ap->a_dvp);
  145         struct timespec ts;
  146         int error;
  147 
  148 #ifdef MSDOSFS_DEBUG
  149         printf("msdosfs_create(cnp %p, vap %p\n", cnp, ap->a_vap);
  150 #endif
  151 
  152         /*
  153          * If this is the root directory and there is no space left we
  154          * can't do anything.  This is because the root directory can not
  155          * change size.
  156          */
  157         if (pdep->de_StartCluster == MSDOSFSROOT
  158             && pdep->de_fndoffset >= pdep->de_FileSize) {
  159                 error = ENOSPC;
  160                 goto bad;
  161         }
  162 
  163         /*
  164          * Create a directory entry for the file, then call createde() to
  165          * have it installed. NOTE: DOS files are always executable.  We
  166          * use the absence of the owner write bit to make the file
  167          * readonly.
  168          */
  169 #ifdef DIAGNOSTIC
  170         if ((cnp->cn_flags & HASBUF) == 0)
  171                 panic("msdosfs_create: no name");
  172 #endif
  173         bzero(&ndirent, sizeof(ndirent));
  174         error = uniqdosname(pdep, cnp, ndirent.de_Name);
  175         if (error)
  176                 goto bad;
  177 
  178         ndirent.de_Attributes = (ap->a_vap->va_mode & VWRITE) ?
  179                                 ATTR_ARCHIVE : ATTR_ARCHIVE | ATTR_READONLY;
  180         ndirent.de_LowerCase = 0;
  181         ndirent.de_StartCluster = 0;
  182         ndirent.de_FileSize = 0;
  183         ndirent.de_dev = pdep->de_dev;
  184         ndirent.de_pmp = pdep->de_pmp;
  185         ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE;
  186         getnanotime(&ts);
  187         DETIMES(&ndirent, &ts, &ts, &ts);
  188         error = createde(&ndirent, pdep, &dep, cnp);
  189         if (error)
  190                 goto bad;
  191         *ap->a_vpp = DETOV(dep);
  192         return (0);
  193 
  194 bad:
  195         return (error);
  196 }
  197 
  198 static int
  199 msdosfs_mknod(ap)
  200         struct vop_mknod_args /* {
  201                 struct vnode *a_dvp;
  202                 struct vnode **a_vpp;
  203                 struct componentname *a_cnp;
  204                 struct vattr *a_vap;
  205         } */ *ap;
  206 {
  207 
  208     return (EINVAL);
  209 }
  210 
  211 static int
  212 msdosfs_open(ap)
  213         struct vop_open_args /* {
  214                 struct vnode *a_vp;
  215                 int a_mode;
  216                 struct ucred *a_cred;
  217                 struct thread *a_td;
  218                 struct file *a_fp;
  219         } */ *ap;
  220 {
  221         struct denode *dep = VTODE(ap->a_vp);
  222         vnode_create_vobject(ap->a_vp, dep->de_FileSize, ap->a_td);
  223         return 0;
  224 }
  225 
  226 static int
  227 msdosfs_close(ap)
  228         struct vop_close_args /* {
  229                 struct vnode *a_vp;
  230                 int a_fflag;
  231                 struct ucred *a_cred;
  232                 struct thread *a_td;
  233         } */ *ap;
  234 {
  235         struct vnode *vp = ap->a_vp;
  236         struct denode *dep = VTODE(vp);
  237         struct timespec ts;
  238 
  239         VI_LOCK(vp);
  240         if (vp->v_usecount > 1) {
  241                 getnanotime(&ts);
  242                 DETIMES(dep, &ts, &ts, &ts);
  243         }
  244         VI_UNLOCK(vp);
  245         return 0;
  246 }
  247 
  248 static int
  249 msdosfs_access(ap)
  250         struct vop_access_args /* {
  251                 struct vnode *a_vp;
  252                 int a_mode;
  253                 struct ucred *a_cred;
  254                 struct thread *a_td;
  255         } */ *ap;
  256 {
  257         struct vnode *vp = ap->a_vp;
  258         struct denode *dep = VTODE(ap->a_vp);
  259         struct msdosfsmount *pmp = dep->de_pmp;
  260         mode_t file_mode, mode = ap->a_mode;
  261 
  262         file_mode = (S_IXUSR|S_IXGRP|S_IXOTH) | (S_IRUSR|S_IRGRP|S_IROTH) |
  263             ((dep->de_Attributes & ATTR_READONLY) ? 0 : (S_IWUSR|S_IWGRP|S_IWOTH));
  264         file_mode &= (vp->v_type == VDIR ? pmp->pm_dirmask : pmp->pm_mask);
  265 
  266         /*
  267          * Disallow writing to directories and regular files if the
  268          * filesystem is read-only.
  269          */
  270         if (mode & VWRITE) {
  271                 switch (vp->v_type) {
  272                 case VDIR:
  273                 case VREG:
  274                         if (vp->v_mount->mnt_flag & MNT_RDONLY)
  275                                 return (EROFS);
  276                         break;
  277                 default:
  278                         break;
  279                 }
  280         }
  281 
  282         return (vaccess(vp->v_type, file_mode, pmp->pm_uid, pmp->pm_gid,
  283             ap->a_mode, ap->a_cred, NULL));
  284 }
  285 
  286 static int
  287 msdosfs_getattr(ap)
  288         struct vop_getattr_args /* {
  289                 struct vnode *a_vp;
  290                 struct vattr *a_vap;
  291                 struct ucred *a_cred;
  292                 struct thread *a_td;
  293         } */ *ap;
  294 {
  295         struct denode *dep = VTODE(ap->a_vp);
  296         struct msdosfsmount *pmp = dep->de_pmp;
  297         struct vattr *vap = ap->a_vap;
  298         mode_t mode;
  299         struct timespec ts;
  300         u_long dirsperblk = pmp->pm_BytesPerSec / sizeof(struct direntry);
  301         uint64_t fileid;
  302 
  303         getnanotime(&ts);
  304         DETIMES(dep, &ts, &ts, &ts);
  305         vap->va_fsid = dev2udev(dep->de_dev);
  306         /*
  307          * The following computation of the fileid must be the same as that
  308          * used in msdosfs_readdir() to compute d_fileno. If not, pwd
  309          * doesn't work.
  310          */
  311         if (dep->de_Attributes & ATTR_DIRECTORY) {
  312                 fileid = (uint64_t)cntobn(pmp, dep->de_StartCluster) *
  313                     dirsperblk;
  314                 if (dep->de_StartCluster == MSDOSFSROOT)
  315                         fileid = 1;
  316         } else {
  317                 fileid = (uint64_t)cntobn(pmp, dep->de_dirclust) *
  318                     dirsperblk;
  319                 if (dep->de_dirclust == MSDOSFSROOT)
  320                         fileid = (uint64_t)roottobn(pmp, 0) * dirsperblk;
  321                 fileid += (uoff_t)dep->de_diroffset / sizeof(struct direntry);
  322         }
  323 
  324         if (pmp->pm_flags & MSDOSFS_LARGEFS)
  325                 vap->va_fileid = msdosfs_fileno_map(pmp->pm_mountp, fileid);
  326         else
  327                 vap->va_fileid = (long)fileid;
  328 
  329         if ((dep->de_Attributes & ATTR_READONLY) == 0)
  330                 mode = S_IRWXU|S_IRWXG|S_IRWXO;
  331         else
  332                 mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH;
  333         vap->va_mode = mode & 
  334             (ap->a_vp->v_type == VDIR ? pmp->pm_dirmask : pmp->pm_mask);
  335         vap->va_uid = pmp->pm_uid;
  336         vap->va_gid = pmp->pm_gid;
  337         vap->va_nlink = 1;
  338         vap->va_rdev = NODEV;
  339         vap->va_size = dep->de_FileSize;
  340         fattime2timespec(dep->de_MDate, dep->de_MTime, 0, 0, &vap->va_mtime);
  341         vap->va_ctime = vap->va_mtime;
  342         if (pmp->pm_flags & MSDOSFSMNT_LONGNAME) {
  343                 fattime2timespec(dep->de_ADate, 0, 0, 0, &vap->va_atime);
  344                 fattime2timespec(dep->de_CDate, dep->de_CTime, dep->de_CHun,
  345                     0, &vap->va_birthtime);
  346         } else {
  347                 vap->va_atime = vap->va_mtime;
  348                 vap->va_birthtime.tv_sec = -1;
  349                 vap->va_birthtime.tv_nsec = 0;
  350         }
  351         vap->va_flags = 0;
  352         if ((dep->de_Attributes & ATTR_ARCHIVE) == 0)
  353                 vap->va_flags |= SF_ARCHIVED;
  354         vap->va_gen = 0;
  355         vap->va_blocksize = pmp->pm_bpcluster;
  356         vap->va_bytes =
  357             (dep->de_FileSize + pmp->pm_crbomask) & ~pmp->pm_crbomask;
  358         vap->va_type = ap->a_vp->v_type;
  359         vap->va_filerev = dep->de_modrev;
  360         return (0);
  361 }
  362 
  363 static int
  364 msdosfs_setattr(ap)
  365         struct vop_setattr_args /* {
  366                 struct vnode *a_vp;
  367                 struct vattr *a_vap;
  368                 struct ucred *a_cred;
  369                 struct thread *a_td;
  370         } */ *ap;
  371 {
  372         struct vnode *vp = ap->a_vp;
  373         struct denode *dep = VTODE(ap->a_vp);
  374         struct msdosfsmount *pmp = dep->de_pmp;
  375         struct vattr *vap = ap->a_vap;
  376         struct ucred *cred = ap->a_cred;
  377         int error = 0;
  378 
  379 #ifdef MSDOSFS_DEBUG
  380         printf("msdosfs_setattr(): vp %p, vap %p, cred %p, p %p\n",
  381             ap->a_vp, vap, cred, ap->a_td);
  382 #endif
  383 
  384         /*
  385          * Check for unsettable attributes.
  386          */
  387         if ((vap->va_type != VNON) || (vap->va_nlink != VNOVAL) ||
  388             (vap->va_fsid != VNOVAL) || (vap->va_fileid != VNOVAL) ||
  389             (vap->va_blocksize != VNOVAL) || (vap->va_rdev != VNOVAL) ||
  390             (vap->va_bytes != VNOVAL) || (vap->va_gen != VNOVAL)) {
  391 #ifdef MSDOSFS_DEBUG
  392                 printf("msdosfs_setattr(): returning EINVAL\n");
  393                 printf("    va_type %d, va_nlink %x, va_fsid %lx, va_fileid %lx\n",
  394                     vap->va_type, vap->va_nlink, vap->va_fsid, vap->va_fileid);
  395                 printf("    va_blocksize %lx, va_rdev %x, va_bytes %qx, va_gen %lx\n",
  396                     vap->va_blocksize, vap->va_rdev, vap->va_bytes, vap->va_gen);
  397                 printf("    va_uid %x, va_gid %x\n",
  398                     vap->va_uid, vap->va_gid);
  399 #endif
  400                 return (EINVAL);
  401         }
  402         if (vap->va_flags != VNOVAL) {
  403                 if (vp->v_mount->mnt_flag & MNT_RDONLY)
  404                         return (EROFS);
  405                 if (cred->cr_uid != pmp->pm_uid) {
  406                         error = priv_check_cred(cred, PRIV_VFS_ADMIN, 0);
  407                         if (error)
  408                                 return (error);
  409                 }
  410                 /*
  411                  * We are very inconsistent about handling unsupported
  412                  * attributes.  We ignored the access time and the
  413                  * read and execute bits.  We were strict for the other
  414                  * attributes.
  415                  *
  416                  * Here we are strict, stricter than ufs in not allowing
  417                  * users to attempt to set SF_SETTABLE bits or anyone to
  418                  * set unsupported bits.  However, we ignore attempts to
  419                  * set ATTR_ARCHIVE for directories `cp -pr' from a more
  420                  * sensible filesystem attempts it a lot.
  421                  */
  422                 if (vap->va_flags & SF_SETTABLE) {
  423                         error = priv_check_cred(cred, PRIV_VFS_SYSFLAGS, 0);
  424                         if (error)
  425                                 return (error);
  426                 }
  427                 if (vap->va_flags & ~SF_ARCHIVED)
  428                         return EOPNOTSUPP;
  429                 if (vap->va_flags & SF_ARCHIVED)
  430                         dep->de_Attributes &= ~ATTR_ARCHIVE;
  431                 else if (!(dep->de_Attributes & ATTR_DIRECTORY))
  432                         dep->de_Attributes |= ATTR_ARCHIVE;
  433                 dep->de_flag |= DE_MODIFIED;
  434         }
  435 
  436         if (vap->va_uid != (uid_t)VNOVAL || vap->va_gid != (gid_t)VNOVAL) {
  437                 uid_t uid;
  438                 gid_t gid;
  439 
  440                 if (vp->v_mount->mnt_flag & MNT_RDONLY)
  441                         return (EROFS);
  442                 uid = vap->va_uid;
  443                 if (uid == (uid_t)VNOVAL)
  444                         uid = pmp->pm_uid;
  445                 gid = vap->va_gid;
  446                 if (gid == (gid_t)VNOVAL)
  447                         gid = pmp->pm_gid;
  448                 if (cred->cr_uid != pmp->pm_uid || uid != pmp->pm_uid ||
  449                     (gid != pmp->pm_gid && !groupmember(gid, cred))) {
  450                         error = priv_check_cred(cred, PRIV_VFS_CHOWN, 0);
  451                         if (error)
  452                                 return (error);
  453                 }
  454                 if (uid != pmp->pm_uid || gid != pmp->pm_gid)
  455                         return EINVAL;
  456         }
  457 
  458         if (vap->va_size != VNOVAL) {
  459                 switch (vp->v_type) {
  460                 case VDIR:
  461                         return (EISDIR);
  462                 case VREG:
  463                         /*
  464                          * Truncation is only supported for regular files,
  465                          * Disallow it if the filesystem is read-only.
  466                          */
  467                         if (vp->v_mount->mnt_flag & MNT_RDONLY)
  468                                 return (EROFS);
  469                         break;
  470                 default:
  471                         /*
  472                          * According to POSIX, the result is unspecified
  473                          * for file types other than regular files,
  474                          * directories and shared memory objects.  We
  475                          * don't support any file types except regular
  476                          * files and directories in this file system, so
  477                          * this (default) case is unreachable and can do
  478                          * anything.  Keep falling through to detrunc()
  479                          * for now.
  480                          */
  481                         break;
  482                 }
  483                 error = detrunc(dep, vap->va_size, 0, cred, ap->a_td);
  484                 if (error)
  485                         return error;
  486         }
  487         if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) {
  488                 if (vp->v_mount->mnt_flag & MNT_RDONLY)
  489                         return (EROFS);
  490                 if (vap->va_vaflags & VA_UTIMES_NULL) {
  491                         error = VOP_ACCESS(vp, VADMIN, cred, ap->a_td); 
  492                         if (error)
  493                                 error = VOP_ACCESS(vp, VWRITE, cred,
  494                                     ap->a_td);
  495                 } else
  496                         error = VOP_ACCESS(vp, VADMIN, cred, ap->a_td);
  497                 if (vp->v_type != VDIR) {
  498                         if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95) == 0 &&
  499                             vap->va_atime.tv_sec != VNOVAL) {
  500                                 dep->de_flag &= ~DE_ACCESS;
  501                                 timespec2fattime(&vap->va_atime, 0,
  502                                     &dep->de_ADate, NULL, NULL);
  503                         }
  504                         if (vap->va_mtime.tv_sec != VNOVAL) {
  505                                 dep->de_flag &= ~DE_UPDATE;
  506                                 timespec2fattime(&vap->va_mtime, 0,
  507                                     &dep->de_MDate, &dep->de_MTime, NULL);
  508                         }
  509                         dep->de_Attributes |= ATTR_ARCHIVE;
  510                         dep->de_flag |= DE_MODIFIED;
  511                 }
  512         }
  513         /*
  514          * DOS files only have the ability to have their writability
  515          * attribute set, so we use the owner write bit to set the readonly
  516          * attribute.
  517          */
  518         if (vap->va_mode != (mode_t)VNOVAL) {
  519                 if (vp->v_mount->mnt_flag & MNT_RDONLY)
  520                         return (EROFS);
  521                 if (cred->cr_uid != pmp->pm_uid) {
  522                         error = priv_check_cred(cred, PRIV_VFS_ADMIN, 0);
  523                         if (error)
  524                                 return (error);
  525                 }
  526                 if (vp->v_type != VDIR) {
  527                         /* We ignore the read and execute bits. */
  528                         if (vap->va_mode & VWRITE)
  529                                 dep->de_Attributes &= ~ATTR_READONLY;
  530                         else
  531                                 dep->de_Attributes |= ATTR_READONLY;
  532                         dep->de_Attributes |= ATTR_ARCHIVE;
  533                         dep->de_flag |= DE_MODIFIED;
  534                 }
  535         }
  536         return (deupdat(dep, 1));
  537 }
  538 
  539 static int
  540 msdosfs_read(ap)
  541         struct vop_read_args /* {
  542                 struct vnode *a_vp;
  543                 struct uio *a_uio;
  544                 int a_ioflag;
  545                 struct ucred *a_cred;
  546         } */ *ap;
  547 {
  548         int error = 0;
  549         int blsize;
  550         int isadir;
  551         int orig_resid;
  552         u_int n;
  553         u_long diff;
  554         u_long on;
  555         daddr_t lbn;
  556         daddr_t rablock;
  557         int rasize;
  558         int seqcount;
  559         struct buf *bp;
  560         struct vnode *vp = ap->a_vp;
  561         struct denode *dep = VTODE(vp);
  562         struct msdosfsmount *pmp = dep->de_pmp;
  563         struct uio *uio = ap->a_uio;
  564 
  565         /*
  566          * If they didn't ask for any data, then we are done.
  567          */
  568         orig_resid = uio->uio_resid;
  569         if (orig_resid == 0)
  570                 return (0);
  571 
  572         /*
  573          * The caller is supposed to ensure that
  574          * uio->uio_offset >= 0 and uio->uio_resid >= 0.
  575          * We don't need to check for large offsets as in ffs because
  576          * dep->de_FileSize <= DOS_FILESIZE_MAX < OFF_MAX, so large
  577          * offsets cannot cause overflow even in theory.
  578          */
  579 
  580         seqcount = ap->a_ioflag >> IO_SEQSHIFT;
  581 
  582         isadir = dep->de_Attributes & ATTR_DIRECTORY;
  583         do {
  584                 if (uio->uio_offset >= dep->de_FileSize)
  585                         break;
  586                 lbn = de_cluster(pmp, uio->uio_offset);
  587                 rablock = lbn + 1;
  588                 blsize = pmp->pm_bpcluster;
  589                 on = uio->uio_offset & pmp->pm_crbomask;
  590                 /*
  591                  * If we are operating on a directory file then be sure to
  592                  * do i/o with the vnode for the filesystem instead of the
  593                  * vnode for the directory.
  594                  */
  595                 if (isadir) {
  596                         /* convert cluster # to block # */
  597                         error = pcbmap(dep, lbn, &lbn, 0, &blsize);
  598                         if (error == E2BIG) {
  599                                 error = EINVAL;
  600                                 break;
  601                         } else if (error)
  602                                 break;
  603                         error = bread(pmp->pm_devvp, lbn, blsize, NOCRED, &bp);
  604                 } else if (de_cn2off(pmp, rablock) >= dep->de_FileSize) {
  605                         error = bread(vp, lbn, blsize, NOCRED, &bp);
  606                 } else if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) {
  607                         error = cluster_read(vp, dep->de_FileSize, lbn, blsize,
  608                             NOCRED, on + uio->uio_resid, seqcount, &bp);
  609                 } else if (seqcount > 1) {
  610                         rasize = blsize;
  611                         error = breadn(vp, lbn,
  612                             blsize, &rablock, &rasize, 1, NOCRED, &bp);
  613                 } else {
  614                         error = bread(vp, lbn, blsize, NOCRED, &bp);
  615                 }
  616                 if (error) {
  617                         brelse(bp);
  618                         break;
  619                 }
  620                 diff = pmp->pm_bpcluster - on;
  621                 n = diff > uio->uio_resid ? uio->uio_resid : diff;
  622                 diff = dep->de_FileSize - uio->uio_offset;
  623                 if (diff < n)
  624                         n = diff;
  625                 diff = blsize - bp->b_resid;
  626                 if (diff < n)
  627                         n = diff;
  628                 error = uiomove(bp->b_data + on, (int) n, uio);
  629                 brelse(bp);
  630         } while (error == 0 && uio->uio_resid > 0 && n != 0);
  631         if (!isadir && (error == 0 || uio->uio_resid != orig_resid) &&
  632             (vp->v_mount->mnt_flag & MNT_NOATIME) == 0)
  633                 dep->de_flag |= DE_ACCESS;
  634         return (error);
  635 }
  636 
  637 /*
  638  * Write data to a file or directory.
  639  */
  640 static int
  641 msdosfs_write(ap)
  642         struct vop_write_args /* {
  643                 struct vnode *a_vp;
  644                 struct uio *a_uio;
  645                 int a_ioflag;
  646                 struct ucred *a_cred;
  647         } */ *ap;
  648 {
  649         int n;
  650         int croffset;
  651         int resid;
  652         u_long osize;
  653         int error = 0;
  654         u_long count;
  655         int seqcount;
  656         daddr_t bn, lastcn;
  657         struct buf *bp;
  658         int ioflag = ap->a_ioflag;
  659         struct uio *uio = ap->a_uio;
  660         struct thread *td = uio->uio_td;
  661         struct vnode *vp = ap->a_vp;
  662         struct vnode *thisvp;
  663         struct denode *dep = VTODE(vp);
  664         struct msdosfsmount *pmp = dep->de_pmp;
  665         struct ucred *cred = ap->a_cred;
  666 
  667 #ifdef MSDOSFS_DEBUG
  668         printf("msdosfs_write(vp %p, uio %p, ioflag %x, cred %p\n",
  669             vp, uio, ioflag, cred);
  670         printf("msdosfs_write(): diroff %lu, dirclust %lu, startcluster %lu\n",
  671             dep->de_diroffset, dep->de_dirclust, dep->de_StartCluster);
  672 #endif
  673 
  674         switch (vp->v_type) {
  675         case VREG:
  676                 if (ioflag & IO_APPEND)
  677                         uio->uio_offset = dep->de_FileSize;
  678                 thisvp = vp;
  679                 break;
  680         case VDIR:
  681                 return EISDIR;
  682         default:
  683                 panic("msdosfs_write(): bad file type");
  684         }
  685 
  686         /*
  687          * This is needed (unlike in ffs_write()) because we extend the
  688          * file outside of the loop but we don't want to extend the file
  689          * for writes of 0 bytes.
  690          */
  691         if (uio->uio_resid == 0)
  692                 return (0);
  693 
  694         /*
  695          * The caller is supposed to ensure that
  696          * uio->uio_offset >= 0 and uio->uio_resid >= 0.
  697          */
  698         if ((uoff_t)uio->uio_offset + uio->uio_resid > DOS_FILESIZE_MAX)
  699                 return (EFBIG);
  700 
  701         /*
  702          * If they've exceeded their filesize limit, tell them about it.
  703          */
  704         if (td != NULL) {
  705                 PROC_LOCK(td->td_proc);
  706                 if ((uoff_t)uio->uio_offset + uio->uio_resid >
  707                     lim_cur(td->td_proc, RLIMIT_FSIZE)) {
  708                         psignal(td->td_proc, SIGXFSZ);
  709                         PROC_UNLOCK(td->td_proc);
  710                         return (EFBIG);
  711                 }
  712                 PROC_UNLOCK(td->td_proc);
  713         }
  714 
  715         /*
  716          * If the offset we are starting the write at is beyond the end of
  717          * the file, then they've done a seek.  Unix filesystems allow
  718          * files with holes in them, DOS doesn't so we must fill the hole
  719          * with zeroed blocks.
  720          */
  721         if (uio->uio_offset > dep->de_FileSize) {
  722                 error = deextend(dep, uio->uio_offset, cred);
  723                 if (error)
  724                         return (error);
  725         }
  726 
  727         /*
  728          * Remember some values in case the write fails.
  729          */
  730         resid = uio->uio_resid;
  731         osize = dep->de_FileSize;
  732 
  733         /*
  734          * If we write beyond the end of the file, extend it to its ultimate
  735          * size ahead of the time to hopefully get a contiguous area.
  736          */
  737         if (uio->uio_offset + resid > osize) {
  738                 count = de_clcount(pmp, uio->uio_offset + resid) -
  739                         de_clcount(pmp, osize);
  740                 error = extendfile(dep, count, NULL, NULL, 0);
  741                 if (error &&  (error != ENOSPC || (ioflag & IO_UNIT)))
  742                         goto errexit;
  743                 lastcn = dep->de_fc[FC_LASTFC].fc_frcn;
  744         } else
  745                 lastcn = de_clcount(pmp, osize) - 1;
  746 
  747         seqcount = ioflag >> IO_SEQSHIFT;
  748         do {
  749                 if (de_cluster(pmp, uio->uio_offset) > lastcn) {
  750                         error = ENOSPC;
  751                         break;
  752                 }
  753 
  754                 croffset = uio->uio_offset & pmp->pm_crbomask;
  755                 n = min(uio->uio_resid, pmp->pm_bpcluster - croffset);
  756                 if (uio->uio_offset + n > dep->de_FileSize) {
  757                         dep->de_FileSize = uio->uio_offset + n;
  758                         /* The object size needs to be set before buffer is allocated */
  759                         vnode_pager_setsize(vp, dep->de_FileSize);
  760                 }
  761 
  762                 bn = de_cluster(pmp, uio->uio_offset);
  763                 if ((uio->uio_offset & pmp->pm_crbomask) == 0
  764                     && (de_cluster(pmp, uio->uio_offset + uio->uio_resid)
  765                         > de_cluster(pmp, uio->uio_offset)
  766                         || uio->uio_offset + uio->uio_resid >= dep->de_FileSize)) {
  767                         /*
  768                          * If either the whole cluster gets written,
  769                          * or we write the cluster from its start beyond EOF,
  770                          * then no need to read data from disk.
  771                          */
  772                         bp = getblk(thisvp, bn, pmp->pm_bpcluster, 0, 0, 0);
  773                         vfs_bio_clrbuf(bp);
  774                         /*
  775                          * Do the bmap now, since pcbmap needs buffers
  776                          * for the fat table. (see msdosfs_strategy)
  777                          */
  778                         if (bp->b_blkno == bp->b_lblkno) {
  779                                 error = pcbmap(dep, bp->b_lblkno, &bn, 0, 0);
  780                                 if (error)
  781                                         bp->b_blkno = -1;
  782                                 else
  783                                         bp->b_blkno = bn;
  784                         }
  785                         if (bp->b_blkno == -1) {
  786                                 brelse(bp);
  787                                 if (!error)
  788                                         error = EIO;            /* XXX */
  789                                 break;
  790                         }
  791                 } else {
  792                         /*
  793                          * The block we need to write into exists, so read it in.
  794                          */
  795                         error = bread(thisvp, bn, pmp->pm_bpcluster, cred, &bp);
  796                         if (error) {
  797                                 brelse(bp);
  798                                 break;
  799                         }
  800                 }
  801 
  802                 /*
  803                  * Should these vnode_pager_* functions be done on dir
  804                  * files?
  805                  */
  806 
  807                 /*
  808                  * Copy the data from user space into the buf header.
  809                  */
  810                 error = uiomove(bp->b_data + croffset, n, uio);
  811                 if (error) {
  812                         brelse(bp);
  813                         break;
  814                 }
  815 
  816                 /* Prepare for clustered writes in some else clauses. */
  817                 if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0)
  818                         bp->b_flags |= B_CLUSTEROK;
  819 
  820                 /*
  821                  * If IO_SYNC, then each buffer is written synchronously.
  822                  * Otherwise, if we have a severe page deficiency then
  823                  * write the buffer asynchronously.  Otherwise, if on a
  824                  * cluster boundary then write the buffer asynchronously,
  825                  * combining it with contiguous clusters if permitted and
  826                  * possible, since we don't expect more writes into this
  827                  * buffer soon.  Otherwise, do a delayed write because we
  828                  * expect more writes into this buffer soon.
  829                  */
  830                 if (ioflag & IO_SYNC)
  831                         (void)bwrite(bp);
  832                 else if (vm_page_count_severe() || buf_dirty_count_severe())
  833                         bawrite(bp);
  834                 else if (n + croffset == pmp->pm_bpcluster) {
  835                         if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0)
  836                                 cluster_write(vp, bp, dep->de_FileSize,
  837                                     seqcount);
  838                         else
  839                                 bawrite(bp);
  840                 } else
  841                         bdwrite(bp);
  842                 dep->de_flag |= DE_UPDATE;
  843         } while (error == 0 && uio->uio_resid > 0);
  844 
  845         /*
  846          * If the write failed and they want us to, truncate the file back
  847          * to the size it was before the write was attempted.
  848          */
  849 errexit:
  850         if (error) {
  851                 if (ioflag & IO_UNIT) {
  852                         detrunc(dep, osize, ioflag & IO_SYNC, NOCRED, NULL);
  853                         uio->uio_offset -= resid - uio->uio_resid;
  854                         uio->uio_resid = resid;
  855                 } else {
  856                         detrunc(dep, dep->de_FileSize, ioflag & IO_SYNC, NOCRED, NULL);
  857                         if (uio->uio_resid != resid)
  858                                 error = 0;
  859                 }
  860         } else if (ioflag & IO_SYNC)
  861                 error = deupdat(dep, 1);
  862         return (error);
  863 }
  864 
  865 /*
  866  * Flush the blocks of a file to disk.
  867  *
  868  * This function is worthless for vnodes that represent directories. Maybe we
  869  * could just do a sync if they try an fsync on a directory file.
  870  */
  871 static int
  872 msdosfs_fsync(ap)
  873         struct vop_fsync_args /* {
  874                 struct vnode *a_vp;
  875                 struct ucred *a_cred;
  876                 int a_waitfor;
  877                 struct thread *a_td;
  878         } */ *ap;
  879 {
  880 
  881         vop_stdfsync(ap);
  882         return (deupdat(VTODE(ap->a_vp), ap->a_waitfor == MNT_WAIT));
  883 }
  884 
  885 static int
  886 msdosfs_remove(ap)
  887         struct vop_remove_args /* {
  888                 struct vnode *a_dvp;
  889                 struct vnode *a_vp;
  890                 struct componentname *a_cnp;
  891         } */ *ap;
  892 {
  893         struct denode *dep = VTODE(ap->a_vp);
  894         struct denode *ddep = VTODE(ap->a_dvp);
  895         int error;
  896 
  897         if (ap->a_vp->v_type == VDIR)
  898                 error = EPERM;
  899         else
  900                 error = removede(ddep, dep);
  901 #ifdef MSDOSFS_DEBUG
  902         printf("msdosfs_remove(), dep %p, v_usecount %d\n", dep, ap->a_vp->v_usecount);
  903 #endif
  904         return (error);
  905 }
  906 
  907 /*
  908  * DOS filesystems don't know what links are.
  909  */
  910 static int
  911 msdosfs_link(ap)
  912         struct vop_link_args /* {
  913                 struct vnode *a_tdvp;
  914                 struct vnode *a_vp;
  915                 struct componentname *a_cnp;
  916         } */ *ap;
  917 {
  918         return (EOPNOTSUPP);
  919 }
  920 
  921 /*
  922  * Renames on files require moving the denode to a new hash queue since the
  923  * denode's location is used to compute which hash queue to put the file
  924  * in. Unless it is a rename in place.  For example "mv a b".
  925  *
  926  * What follows is the basic algorithm:
  927  *
  928  * if (file move) {
  929  *      if (dest file exists) {
  930  *              remove dest file
  931  *      }
  932  *      if (dest and src in same directory) {
  933  *              rewrite name in existing directory slot
  934  *      } else {
  935  *              write new entry in dest directory
  936  *              update offset and dirclust in denode
  937  *              move denode to new hash chain
  938  *              clear old directory entry
  939  *      }
  940  * } else {
  941  *      directory move
  942  *      if (dest directory exists) {
  943  *              if (dest is not empty) {
  944  *                      return ENOTEMPTY
  945  *              }
  946  *              remove dest directory
  947  *      }
  948  *      if (dest and src in same directory) {
  949  *              rewrite name in existing entry
  950  *      } else {
  951  *              be sure dest is not a child of src directory
  952  *              write entry in dest directory
  953  *              update "." and ".." in moved directory
  954  *              clear old directory entry for moved directory
  955  *      }
  956  * }
  957  *
  958  * On entry:
  959  *      source's parent directory is unlocked
  960  *      source file or directory is unlocked
  961  *      destination's parent directory is locked
  962  *      destination file or directory is locked if it exists
  963  *
  964  * On exit:
  965  *      all denodes should be released
  966  */
  967 static int
  968 msdosfs_rename(ap)
  969         struct vop_rename_args /* {
  970                 struct vnode *a_fdvp;
  971                 struct vnode *a_fvp;
  972                 struct componentname *a_fcnp;
  973                 struct vnode *a_tdvp;
  974                 struct vnode *a_tvp;
  975                 struct componentname *a_tcnp;
  976         } */ *ap;
  977 {
  978         struct vnode *tdvp = ap->a_tdvp;
  979         struct vnode *fvp = ap->a_fvp;
  980         struct vnode *fdvp = ap->a_fdvp;
  981         struct vnode *tvp = ap->a_tvp;
  982         struct componentname *tcnp = ap->a_tcnp;
  983         struct componentname *fcnp = ap->a_fcnp;
  984         struct thread *td = fcnp->cn_thread;
  985         struct denode *ip, *xp, *dp, *zp;
  986         u_char toname[12], oldname[11];
  987         u_long from_diroffset, to_diroffset;
  988         u_char to_count;
  989         int doingdirectory = 0, newparent = 0;
  990         int error;
  991         u_long cn;
  992         daddr_t bn;
  993         struct denode *fddep;   /* from file's parent directory  */
  994         struct msdosfsmount *pmp;
  995         struct direntry *dotdotp;
  996         struct buf *bp;
  997 
  998         fddep = VTODE(ap->a_fdvp);
  999         pmp = fddep->de_pmp;
 1000 
 1001         pmp = VFSTOMSDOSFS(fdvp->v_mount);
 1002 
 1003 #ifdef DIAGNOSTIC
 1004         if ((tcnp->cn_flags & HASBUF) == 0 ||
 1005             (fcnp->cn_flags & HASBUF) == 0)
 1006                 panic("msdosfs_rename: no name");
 1007 #endif
 1008         /*
 1009          * Check for cross-device rename.
 1010          */
 1011         if (fvp->v_mount != tdvp->v_mount ||
 1012             (tvp && fvp->v_mount != tvp->v_mount)) {
 1013                 error = EXDEV;
 1014 abortit:
 1015                 if (tdvp == tvp)
 1016                         vrele(tdvp);
 1017                 else
 1018                         vput(tdvp);
 1019                 if (tvp)
 1020                         vput(tvp);
 1021                 vrele(fdvp);
 1022                 vrele(fvp);
 1023                 return (error);
 1024         }
 1025 
 1026         /*
 1027          * If source and dest are the same, do nothing.
 1028          */
 1029         if (tvp == fvp) {
 1030                 error = 0;
 1031                 goto abortit;
 1032         }
 1033 
 1034         error = vn_lock(fvp, LK_EXCLUSIVE, td);
 1035         if (error)
 1036                 goto abortit;
 1037         dp = VTODE(fdvp);
 1038         ip = VTODE(fvp);
 1039 
 1040         /*
 1041          * Be sure we are not renaming ".", "..", or an alias of ".". This
 1042          * leads to a crippled directory tree.  It's pretty tough to do a
 1043          * "ls" or "pwd" with the "." directory entry missing, and "cd .."
 1044          * doesn't work if the ".." entry is missing.
 1045          */
 1046         if (ip->de_Attributes & ATTR_DIRECTORY) {
 1047                 /*
 1048                  * Avoid ".", "..", and aliases of "." for obvious reasons.
 1049                  */
 1050                 if ((fcnp->cn_namelen == 1 && fcnp->cn_nameptr[0] == '.') ||
 1051                     dp == ip ||
 1052                     (fcnp->cn_flags & ISDOTDOT) ||
 1053                     (tcnp->cn_flags & ISDOTDOT) ||
 1054                     (ip->de_flag & DE_RENAME)) {
 1055                         VOP_UNLOCK(fvp, 0, td);
 1056                         error = EINVAL;
 1057                         goto abortit;
 1058                 }
 1059                 ip->de_flag |= DE_RENAME;
 1060                 doingdirectory++;
 1061         }
 1062 
 1063         /*
 1064          * When the target exists, both the directory
 1065          * and target vnodes are returned locked.
 1066          */
 1067         dp = VTODE(tdvp);
 1068         xp = tvp ? VTODE(tvp) : NULL;
 1069         /*
 1070          * Remember direntry place to use for destination
 1071          */
 1072         to_diroffset = dp->de_fndoffset;
 1073         to_count = dp->de_fndcnt;
 1074 
 1075         /*
 1076          * If ".." must be changed (ie the directory gets a new
 1077          * parent) then the source directory must not be in the
 1078          * directory heirarchy above the target, as this would
 1079          * orphan everything below the source directory. Also
 1080          * the user must have write permission in the source so
 1081          * as to be able to change "..". We must repeat the call
 1082          * to namei, as the parent directory is unlocked by the
 1083          * call to doscheckpath().
 1084          */
 1085         error = VOP_ACCESS(fvp, VWRITE, tcnp->cn_cred, tcnp->cn_thread);
 1086         VOP_UNLOCK(fvp, 0, td);
 1087         if (VTODE(fdvp)->de_StartCluster != VTODE(tdvp)->de_StartCluster)
 1088                 newparent = 1;
 1089         if (doingdirectory && newparent) {
 1090                 if (error)      /* write access check above */
 1091                         goto bad;
 1092                 if (xp != NULL)
 1093                         vput(tvp);
 1094                 /*
 1095                  * doscheckpath() vput()'s dp,
 1096                  * so we have to do a relookup afterwards
 1097                  */
 1098                 error = doscheckpath(ip, dp);
 1099                 if (error)
 1100                         goto out;
 1101                 if ((tcnp->cn_flags & SAVESTART) == 0)
 1102                         panic("msdosfs_rename: lost to startdir");
 1103                 error = relookup(tdvp, &tvp, tcnp);
 1104                 if (error)
 1105                         goto out;
 1106                 dp = VTODE(tdvp);
 1107                 xp = tvp ? VTODE(tvp) : NULL;
 1108         }
 1109 
 1110         if (xp != NULL) {
 1111                 /*
 1112                  * Target must be empty if a directory and have no links
 1113                  * to it. Also, ensure source and target are compatible
 1114                  * (both directories, or both not directories).
 1115                  */
 1116                 if (xp->de_Attributes & ATTR_DIRECTORY) {
 1117                         if (!dosdirempty(xp)) {
 1118                                 error = ENOTEMPTY;
 1119                                 goto bad;
 1120                         }
 1121                         if (!doingdirectory) {
 1122                                 error = ENOTDIR;
 1123                                 goto bad;
 1124                         }
 1125                         cache_purge(tdvp);
 1126                 } else if (doingdirectory) {
 1127                         error = EISDIR;
 1128                         goto bad;
 1129                 }
 1130                 error = removede(dp, xp);
 1131                 if (error)
 1132                         goto bad;
 1133                 vput(tvp);
 1134                 xp = NULL;
 1135         }
 1136 
 1137         /*
 1138          * Convert the filename in tcnp into a dos filename. We copy this
 1139          * into the denode and directory entry for the destination
 1140          * file/directory.
 1141          */
 1142         error = uniqdosname(VTODE(tdvp), tcnp, toname);
 1143         if (error)
 1144                 goto abortit;
 1145 
 1146         /*
 1147          * Since from wasn't locked at various places above,
 1148          * have to do a relookup here.
 1149          */
 1150         fcnp->cn_flags &= ~MODMASK;
 1151         fcnp->cn_flags |= LOCKPARENT | LOCKLEAF;
 1152         if ((fcnp->cn_flags & SAVESTART) == 0)
 1153                 panic("msdosfs_rename: lost from startdir");
 1154         if (!newparent)
 1155                 VOP_UNLOCK(tdvp, 0, td);
 1156         if (relookup(fdvp, &fvp, fcnp) == 0)
 1157                 vrele(fdvp);
 1158         if (fvp == NULL) {
 1159                 /*
 1160                  * From name has disappeared.
 1161                  */
 1162                 if (doingdirectory)
 1163                         panic("rename: lost dir entry");
 1164                 if (newparent)
 1165                         VOP_UNLOCK(tdvp, 0, td);
 1166                 vrele(tdvp);
 1167                 vrele(ap->a_fvp);
 1168                 return 0;
 1169         }
 1170         xp = VTODE(fvp);
 1171         zp = VTODE(fdvp);
 1172         from_diroffset = zp->de_fndoffset;
 1173 
 1174         /*
 1175          * Ensure that the directory entry still exists and has not
 1176          * changed till now. If the source is a file the entry may
 1177          * have been unlinked or renamed. In either case there is
 1178          * no further work to be done. If the source is a directory
 1179          * then it cannot have been rmdir'ed or renamed; this is
 1180          * prohibited by the DE_RENAME flag.
 1181          */
 1182         if (xp != ip) {
 1183                 if (doingdirectory)
 1184                         panic("rename: lost dir entry");
 1185                 VOP_UNLOCK(fvp, 0, td);
 1186                 if (newparent)
 1187                         VOP_UNLOCK(fdvp, 0, td);
 1188                 vrele(ap->a_fvp);
 1189                 xp = NULL;
 1190         } else {
 1191                 vrele(fvp);
 1192                 xp = NULL;
 1193 
 1194                 /*
 1195                  * First write a new entry in the destination
 1196                  * directory and mark the entry in the source directory
 1197                  * as deleted.  Then move the denode to the correct hash
 1198                  * chain for its new location in the filesystem.  And, if
 1199                  * we moved a directory, then update its .. entry to point
 1200                  * to the new parent directory.
 1201                  */
 1202                 bcopy(ip->de_Name, oldname, 11);
 1203                 bcopy(toname, ip->de_Name, 11); /* update denode */
 1204                 dp->de_fndoffset = to_diroffset;
 1205                 dp->de_fndcnt = to_count;
 1206                 error = createde(ip, dp, (struct denode **)0, tcnp);
 1207                 if (error) {
 1208                         bcopy(oldname, ip->de_Name, 11);
 1209                         if (newparent)
 1210                                 VOP_UNLOCK(fdvp, 0, td);
 1211                         VOP_UNLOCK(fvp, 0, td);
 1212                         goto bad;
 1213                 }
 1214                 ip->de_refcnt++;
 1215                 zp->de_fndoffset = from_diroffset;
 1216                 error = removede(zp, ip);
 1217                 if (error) {
 1218                         /* XXX should downgrade to ro here, fs is corrupt */
 1219                         if (newparent)
 1220                                 VOP_UNLOCK(fdvp, 0, td);
 1221                         VOP_UNLOCK(fvp, 0, td);
 1222                         goto bad;
 1223                 }
 1224                 if (!doingdirectory) {
 1225                         error = pcbmap(dp, de_cluster(pmp, to_diroffset), 0,
 1226                                        &ip->de_dirclust, 0);
 1227                         if (error) {
 1228                                 /* XXX should downgrade to ro here, fs is corrupt */
 1229                                 if (newparent)
 1230                                         VOP_UNLOCK(fdvp, 0, td);
 1231                                 VOP_UNLOCK(fvp, 0, td);
 1232                                 goto bad;
 1233                         }
 1234                         if (ip->de_dirclust == MSDOSFSROOT)
 1235                                 ip->de_diroffset = to_diroffset;
 1236                         else
 1237                                 ip->de_diroffset = to_diroffset & pmp->pm_crbomask;
 1238                 }
 1239                 reinsert(ip);
 1240                 if (newparent)
 1241                         VOP_UNLOCK(fdvp, 0, td);
 1242         }
 1243 
 1244         /*
 1245          * If we moved a directory to a new parent directory, then we must
 1246          * fixup the ".." entry in the moved directory.
 1247          */
 1248         if (doingdirectory && newparent) {
 1249                 cn = ip->de_StartCluster;
 1250                 if (cn == MSDOSFSROOT) {
 1251                         /* this should never happen */
 1252                         panic("msdosfs_rename(): updating .. in root directory?");
 1253                 } else
 1254                         bn = cntobn(pmp, cn);
 1255                 error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster,
 1256                               NOCRED, &bp);
 1257                 if (error) {
 1258                         /* XXX should downgrade to ro here, fs is corrupt */
 1259                         brelse(bp);
 1260                         VOP_UNLOCK(fvp, 0, td);
 1261                         goto bad;
 1262                 }
 1263                 dotdotp = (struct direntry *)bp->b_data + 1;
 1264                 putushort(dotdotp->deStartCluster, dp->de_StartCluster);
 1265                 if (FAT32(pmp))
 1266                         putushort(dotdotp->deHighClust, dp->de_StartCluster >> 16);
 1267                 error = bwrite(bp);
 1268                 if (error) {
 1269                         /* XXX should downgrade to ro here, fs is corrupt */
 1270                         VOP_UNLOCK(fvp, 0, td);
 1271                         goto bad;
 1272                 }
 1273         }
 1274 
 1275         VOP_UNLOCK(fvp, 0, td);
 1276 bad:
 1277         if (xp)
 1278                 vput(tvp);
 1279         vput(tdvp);
 1280 out:
 1281         ip->de_flag &= ~DE_RENAME;
 1282         vrele(fdvp);
 1283         vrele(fvp);
 1284         return (error);
 1285 
 1286 }
 1287 
 1288 static struct {
 1289         struct direntry dot;
 1290         struct direntry dotdot;
 1291 } dosdirtemplate = {
 1292         {       ".       ", "   ",                      /* the . entry */
 1293                 ATTR_DIRECTORY,                         /* file attribute */
 1294                 0,                                      /* reserved */
 1295                 0, { 0, 0 }, { 0, 0 },                  /* create time & date */
 1296                 { 0, 0 },                               /* access date */
 1297                 { 0, 0 },                               /* high bits of start cluster */
 1298                 { 210, 4 }, { 210, 4 },                 /* modify time & date */
 1299                 { 0, 0 },                               /* startcluster */
 1300                 { 0, 0, 0, 0 }                          /* filesize */
 1301         },
 1302         {       "..      ", "   ",                      /* the .. entry */
 1303                 ATTR_DIRECTORY,                         /* file attribute */
 1304                 0,                                      /* reserved */
 1305                 0, { 0, 0 }, { 0, 0 },                  /* create time & date */
 1306                 { 0, 0 },                               /* access date */
 1307                 { 0, 0 },                               /* high bits of start cluster */
 1308                 { 210, 4 }, { 210, 4 },                 /* modify time & date */
 1309                 { 0, 0 },                               /* startcluster */
 1310                 { 0, 0, 0, 0 }                          /* filesize */
 1311         }
 1312 };
 1313 
 1314 static int
 1315 msdosfs_mkdir(ap)
 1316         struct vop_mkdir_args /* {
 1317                 struct vnode *a_dvp;
 1318                 struct vnode **a_vpp;
 1319                 struvt componentname *a_cnp;
 1320                 struct vattr *a_vap;
 1321         } */ *ap;
 1322 {
 1323         struct componentname *cnp = ap->a_cnp;
 1324         struct denode *dep;
 1325         struct denode *pdep = VTODE(ap->a_dvp);
 1326         struct direntry *denp;
 1327         struct msdosfsmount *pmp = pdep->de_pmp;
 1328         struct buf *bp;
 1329         u_long newcluster, pcl;
 1330         int bn;
 1331         int error;
 1332         struct denode ndirent;
 1333         struct timespec ts;
 1334 
 1335         /*
 1336          * If this is the root directory and there is no space left we
 1337          * can't do anything.  This is because the root directory can not
 1338          * change size.
 1339          */
 1340         if (pdep->de_StartCluster == MSDOSFSROOT
 1341             && pdep->de_fndoffset >= pdep->de_FileSize) {
 1342                 error = ENOSPC;
 1343                 goto bad2;
 1344         }
 1345 
 1346         /*
 1347          * Allocate a cluster to hold the about to be created directory.
 1348          */
 1349         error = clusteralloc(pmp, 0, 1, CLUST_EOFE, &newcluster, NULL);
 1350         if (error)
 1351                 goto bad2;
 1352 
 1353         bzero(&ndirent, sizeof(ndirent));
 1354         ndirent.de_pmp = pmp;
 1355         ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE;
 1356         getnanotime(&ts);
 1357         DETIMES(&ndirent, &ts, &ts, &ts);
 1358 
 1359         /*
 1360          * Now fill the cluster with the "." and ".." entries. And write
 1361          * the cluster to disk.  This way it is there for the parent
 1362          * directory to be pointing at if there were a crash.
 1363          */
 1364         bn = cntobn(pmp, newcluster);
 1365         /* always succeeds */
 1366         bp = getblk(pmp->pm_devvp, bn, pmp->pm_bpcluster, 0, 0, 0);
 1367         bzero(bp->b_data, pmp->pm_bpcluster);
 1368         bcopy(&dosdirtemplate, bp->b_data, sizeof dosdirtemplate);
 1369         denp = (struct direntry *)bp->b_data;
 1370         putushort(denp[0].deStartCluster, newcluster);
 1371         putushort(denp[0].deCDate, ndirent.de_CDate);
 1372         putushort(denp[0].deCTime, ndirent.de_CTime);
 1373         denp[0].deCHundredth = ndirent.de_CHun;
 1374         putushort(denp[0].deADate, ndirent.de_ADate);
 1375         putushort(denp[0].deMDate, ndirent.de_MDate);
 1376         putushort(denp[0].deMTime, ndirent.de_MTime);
 1377         pcl = pdep->de_StartCluster;
 1378         if (FAT32(pmp) && pcl == pmp->pm_rootdirblk)
 1379                 pcl = 0;
 1380         putushort(denp[1].deStartCluster, pcl);
 1381         putushort(denp[1].deCDate, ndirent.de_CDate);
 1382         putushort(denp[1].deCTime, ndirent.de_CTime);
 1383         denp[1].deCHundredth = ndirent.de_CHun;
 1384         putushort(denp[1].deADate, ndirent.de_ADate);
 1385         putushort(denp[1].deMDate, ndirent.de_MDate);
 1386         putushort(denp[1].deMTime, ndirent.de_MTime);
 1387         if (FAT32(pmp)) {
 1388                 putushort(denp[0].deHighClust, newcluster >> 16);
 1389                 putushort(denp[1].deHighClust, pdep->de_StartCluster >> 16);
 1390         }
 1391 
 1392         error = bwrite(bp);
 1393         if (error)
 1394                 goto bad;
 1395 
 1396         /*
 1397          * Now build up a directory entry pointing to the newly allocated
 1398          * cluster.  This will be written to an empty slot in the parent
 1399          * directory.
 1400          */
 1401 #ifdef DIAGNOSTIC
 1402         if ((cnp->cn_flags & HASBUF) == 0)
 1403                 panic("msdosfs_mkdir: no name");
 1404 #endif
 1405         error = uniqdosname(pdep, cnp, ndirent.de_Name);
 1406         if (error)
 1407                 goto bad;
 1408 
 1409         ndirent.de_Attributes = ATTR_DIRECTORY;
 1410         ndirent.de_LowerCase = 0;
 1411         ndirent.de_StartCluster = newcluster;
 1412         ndirent.de_FileSize = 0;
 1413         ndirent.de_dev = pdep->de_dev;
 1414         error = createde(&ndirent, pdep, &dep, cnp);
 1415         if (error)
 1416                 goto bad;
 1417         *ap->a_vpp = DETOV(dep);
 1418         return (0);
 1419 
 1420 bad:
 1421         clusterfree(pmp, newcluster, NULL);
 1422 bad2:
 1423         return (error);
 1424 }
 1425 
 1426 static int
 1427 msdosfs_rmdir(ap)
 1428         struct vop_rmdir_args /* {
 1429                 struct vnode *a_dvp;
 1430                 struct vnode *a_vp;
 1431                 struct componentname *a_cnp;
 1432         } */ *ap;
 1433 {
 1434         struct vnode *vp = ap->a_vp;
 1435         struct vnode *dvp = ap->a_dvp;
 1436         struct componentname *cnp = ap->a_cnp;
 1437         struct denode *ip, *dp;
 1438         struct thread *td = cnp->cn_thread;
 1439         int error;
 1440 
 1441         ip = VTODE(vp);
 1442         dp = VTODE(dvp);
 1443 
 1444         /*
 1445          * Verify the directory is empty (and valid).
 1446          * (Rmdir ".." won't be valid since
 1447          *  ".." will contain a reference to
 1448          *  the current directory and thus be
 1449          *  non-empty.)
 1450          */
 1451         error = 0;
 1452         if (!dosdirempty(ip) || ip->de_flag & DE_RENAME) {
 1453                 error = ENOTEMPTY;
 1454                 goto out;
 1455         }
 1456         /*
 1457          * Delete the entry from the directory.  For dos filesystems this
 1458          * gets rid of the directory entry on disk, the in memory copy
 1459          * still exists but the de_refcnt is <= 0.  This prevents it from
 1460          * being found by deget().  When the vput() on dep is done we give
 1461          * up access and eventually msdosfs_reclaim() will be called which
 1462          * will remove it from the denode cache.
 1463          */
 1464         error = removede(dp, ip);
 1465         if (error)
 1466                 goto out;
 1467         /*
 1468          * This is where we decrement the link count in the parent
 1469          * directory.  Since dos filesystems don't do this we just purge
 1470          * the name cache.
 1471          */
 1472         cache_purge(dvp);
 1473         VOP_UNLOCK(dvp, 0, td);
 1474         /*
 1475          * Truncate the directory that is being deleted.
 1476          */
 1477         error = detrunc(ip, (u_long)0, IO_SYNC, cnp->cn_cred, td);
 1478         cache_purge(vp);
 1479 
 1480         vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, td);
 1481 out:
 1482         return (error);
 1483 }
 1484 
 1485 /*
 1486  * DOS filesystems don't know what symlinks are.
 1487  */
 1488 static int
 1489 msdosfs_symlink(ap)
 1490         struct vop_symlink_args /* {
 1491                 struct vnode *a_dvp;
 1492                 struct vnode **a_vpp;
 1493                 struct componentname *a_cnp;
 1494                 struct vattr *a_vap;
 1495                 char *a_target;
 1496         } */ *ap;
 1497 {
 1498         return (EOPNOTSUPP);
 1499 }
 1500 
 1501 static int
 1502 msdosfs_readdir(ap)
 1503         struct vop_readdir_args /* {
 1504                 struct vnode *a_vp;
 1505                 struct uio *a_uio;
 1506                 struct ucred *a_cred;
 1507                 int *a_eofflag;
 1508                 int *a_ncookies;
 1509                 u_long **a_cookies;
 1510         } */ *ap;
 1511 {
 1512         struct mbnambuf nb;
 1513         int error = 0;
 1514         int diff;
 1515         long n;
 1516         int blsize;
 1517         long on;
 1518         u_long cn;
 1519         uint64_t fileno;
 1520         u_long dirsperblk;
 1521         long bias = 0;
 1522         daddr_t bn, lbn;
 1523         struct buf *bp;
 1524         struct denode *dep = VTODE(ap->a_vp);
 1525         struct msdosfsmount *pmp = dep->de_pmp;
 1526         struct direntry *dentp;
 1527         struct dirent dirbuf;
 1528         struct uio *uio = ap->a_uio;
 1529         u_long *cookies = NULL;
 1530         int ncookies = 0;
 1531         off_t offset, off;
 1532         int chksum = -1;
 1533 
 1534 #ifdef MSDOSFS_DEBUG
 1535         printf("msdosfs_readdir(): vp %p, uio %p, cred %p, eofflagp %p\n",
 1536             ap->a_vp, uio, ap->a_cred, ap->a_eofflag);
 1537 #endif
 1538 
 1539         /*
 1540          * msdosfs_readdir() won't operate properly on regular files since
 1541          * it does i/o only with the filesystem vnode, and hence can
 1542          * retrieve the wrong block from the buffer cache for a plain file.
 1543          * So, fail attempts to readdir() on a plain file.
 1544          */
 1545         if ((dep->de_Attributes & ATTR_DIRECTORY) == 0)
 1546                 return (ENOTDIR);
 1547 
 1548         /*
 1549          * To be safe, initialize dirbuf
 1550          */
 1551         bzero(dirbuf.d_name, sizeof(dirbuf.d_name));
 1552 
 1553         /*
 1554          * If the user buffer is smaller than the size of one dos directory
 1555          * entry or the file offset is not a multiple of the size of a
 1556          * directory entry, then we fail the read.
 1557          */
 1558         off = offset = uio->uio_offset;
 1559         if (uio->uio_resid < sizeof(struct direntry) ||
 1560             (offset & (sizeof(struct direntry) - 1)))
 1561                 return (EINVAL);
 1562 
 1563         if (ap->a_ncookies) {
 1564                 ncookies = uio->uio_resid / 16;
 1565                 MALLOC(cookies, u_long *, ncookies * sizeof(u_long), M_TEMP,
 1566                        M_WAITOK);
 1567                 *ap->a_cookies = cookies;
 1568                 *ap->a_ncookies = ncookies;
 1569         }
 1570 
 1571         dirsperblk = pmp->pm_BytesPerSec / sizeof(struct direntry);
 1572 
 1573         /*
 1574          * If they are reading from the root directory then, we simulate
 1575          * the . and .. entries since these don't exist in the root
 1576          * directory.  We also set the offset bias to make up for having to
 1577          * simulate these entries. By this I mean that at file offset 64 we
 1578          * read the first entry in the root directory that lives on disk.
 1579          */
 1580         if (dep->de_StartCluster == MSDOSFSROOT
 1581             || (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk)) {
 1582 #if 0
 1583                 printf("msdosfs_readdir(): going after . or .. in root dir, offset %d\n",
 1584                     offset);
 1585 #endif
 1586                 bias = 2 * sizeof(struct direntry);
 1587                 if (offset < bias) {
 1588                         for (n = (int)offset / sizeof(struct direntry);
 1589                              n < 2; n++) {
 1590                                 if (FAT32(pmp))
 1591                                         fileno = (uint64_t)cntobn(pmp,
 1592                                                                  pmp->pm_rootdirblk)
 1593                                                           * dirsperblk;
 1594                                 else
 1595                                         fileno = 1;
 1596                                 if (pmp->pm_flags & MSDOSFS_LARGEFS) {
 1597                                         dirbuf.d_fileno =
 1598                                             msdosfs_fileno_map(pmp->pm_mountp,
 1599                                             fileno);
 1600                                 } else {
 1601 
 1602                                         dirbuf.d_fileno = (uint32_t)fileno;
 1603                                 }
 1604                                 dirbuf.d_type = DT_DIR;
 1605                                 switch (n) {
 1606                                 case 0:
 1607                                         dirbuf.d_namlen = 1;
 1608                                         strcpy(dirbuf.d_name, ".");
 1609                                         break;
 1610                                 case 1:
 1611                                         dirbuf.d_namlen = 2;
 1612                                         strcpy(dirbuf.d_name, "..");
 1613                                         break;
 1614                                 }
 1615                                 dirbuf.d_reclen = GENERIC_DIRSIZ(&dirbuf);
 1616                                 if (uio->uio_resid < dirbuf.d_reclen)
 1617                                         goto out;
 1618                                 error = uiomove(&dirbuf, dirbuf.d_reclen, uio);
 1619                                 if (error)
 1620                                         goto out;
 1621                                 offset += sizeof(struct direntry);
 1622                                 off = offset;
 1623                                 if (cookies) {
 1624                                         *cookies++ = offset;
 1625                                         if (--ncookies <= 0)
 1626                                                 goto out;
 1627                                 }
 1628                         }
 1629                 }
 1630         }
 1631 
 1632         mbnambuf_init(&nb);
 1633         off = offset;
 1634         while (uio->uio_resid > 0) {
 1635                 lbn = de_cluster(pmp, offset - bias);
 1636                 on = (offset - bias) & pmp->pm_crbomask;
 1637                 n = min(pmp->pm_bpcluster - on, uio->uio_resid);
 1638                 diff = dep->de_FileSize - (offset - bias);
 1639                 if (diff <= 0)
 1640                         break;
 1641                 n = min(n, diff);
 1642                 error = pcbmap(dep, lbn, &bn, &cn, &blsize);
 1643                 if (error)
 1644                         break;
 1645                 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
 1646                 if (error) {
 1647                         brelse(bp);
 1648                         return (error);
 1649                 }
 1650                 n = min(n, blsize - bp->b_resid);
 1651                 if (n == 0) {
 1652                         brelse(bp);
 1653                         return (EIO);
 1654                 }
 1655 
 1656                 /*
 1657                  * Convert from dos directory entries to fs-independent
 1658                  * directory entries.
 1659                  */
 1660                 for (dentp = (struct direntry *)(bp->b_data + on);
 1661                      (char *)dentp < bp->b_data + on + n;
 1662                      dentp++, offset += sizeof(struct direntry)) {
 1663 #if 0
 1664                         printf("rd: dentp %08x prev %08x crnt %08x deName %02x attr %02x\n",
 1665                             dentp, prev, crnt, dentp->deName[0], dentp->deAttributes);
 1666 #endif
 1667                         /*
 1668                          * If this is an unused entry, we can stop.
 1669                          */
 1670                         if (dentp->deName[0] == SLOT_EMPTY) {
 1671                                 brelse(bp);
 1672                                 goto out;
 1673                         }
 1674                         /*
 1675                          * Skip deleted entries.
 1676                          */
 1677                         if (dentp->deName[0] == SLOT_DELETED) {
 1678                                 chksum = -1;
 1679                                 mbnambuf_init(&nb);
 1680                                 continue;
 1681                         }
 1682 
 1683                         /*
 1684                          * Handle Win95 long directory entries
 1685                          */
 1686                         if (dentp->deAttributes == ATTR_WIN95) {
 1687                                 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
 1688                                         continue;
 1689                                 chksum = win2unixfn(&nb,
 1690                                     (struct winentry *)dentp, chksum, pmp);
 1691                                 continue;
 1692                         }
 1693 
 1694                         /*
 1695                          * Skip volume labels
 1696                          */
 1697                         if (dentp->deAttributes & ATTR_VOLUME) {
 1698                                 chksum = -1;
 1699                                 mbnambuf_init(&nb);
 1700                                 continue;
 1701                         }
 1702                         /*
 1703                          * This computation of d_fileno must match
 1704                          * the computation of va_fileid in
 1705                          * msdosfs_getattr.
 1706                          */
 1707                         if (dentp->deAttributes & ATTR_DIRECTORY) {
 1708                                 fileno = getushort(dentp->deStartCluster);
 1709                                 if (FAT32(pmp))
 1710                                         fileno |= getushort(dentp->deHighClust) << 16;
 1711                                 /* if this is the root directory */
 1712                                 if (fileno == MSDOSFSROOT)
 1713                                         if (FAT32(pmp))
 1714                                                 fileno = (uint64_t)cntobn(pmp,
 1715                                                                 pmp->pm_rootdirblk)
 1716                                                          * dirsperblk;
 1717                                         else
 1718                                                 fileno = 1;
 1719                                 else
 1720                                         fileno = (uint64_t)cntobn(pmp, fileno) *
 1721                                             dirsperblk;
 1722                                 dirbuf.d_type = DT_DIR;
 1723                         } else {
 1724                                 fileno = (uoff_t)offset /
 1725                                     sizeof(struct direntry);
 1726                                 dirbuf.d_type = DT_REG;
 1727                         }
 1728                         if (pmp->pm_flags & MSDOSFS_LARGEFS) {
 1729                                 dirbuf.d_fileno =
 1730                                     msdosfs_fileno_map(pmp->pm_mountp, fileno);
 1731                         } else
 1732                                 dirbuf.d_fileno = (uint32_t)fileno;
 1733 
 1734                         if (chksum != winChksum(dentp)) {
 1735                                 dirbuf.d_namlen = dos2unixfn(dentp->deName,
 1736                                     (u_char *)dirbuf.d_name,
 1737                                     dentp->deLowerCase |
 1738                                         ((pmp->pm_flags & MSDOSFSMNT_SHORTNAME) ?
 1739                                         (LCASE_BASE | LCASE_EXT) : 0),
 1740                                     pmp);
 1741                                 mbnambuf_init(&nb);
 1742                         } else
 1743                                 mbnambuf_flush(&nb, &dirbuf);
 1744                         chksum = -1;
 1745                         dirbuf.d_reclen = GENERIC_DIRSIZ(&dirbuf);
 1746                         if (uio->uio_resid < dirbuf.d_reclen) {
 1747                                 brelse(bp);
 1748                                 goto out;
 1749                         }
 1750                         error = uiomove(&dirbuf, dirbuf.d_reclen, uio);
 1751                         if (error) {
 1752                                 brelse(bp);
 1753                                 goto out;
 1754                         }
 1755                         if (cookies) {
 1756                                 *cookies++ = offset + sizeof(struct direntry);
 1757                                 if (--ncookies <= 0) {
 1758                                         brelse(bp);
 1759                                         goto out;
 1760                                 }
 1761                         }
 1762                         off = offset + sizeof(struct direntry);
 1763                 }
 1764                 brelse(bp);
 1765         }
 1766 out:
 1767         /* Subtract unused cookies */
 1768         if (ap->a_ncookies)
 1769                 *ap->a_ncookies -= ncookies;
 1770 
 1771         uio->uio_offset = off;
 1772 
 1773         /*
 1774          * Set the eofflag (NFS uses it)
 1775          */
 1776         if (ap->a_eofflag) {
 1777                 if (dep->de_FileSize - (offset - bias) <= 0)
 1778                         *ap->a_eofflag = 1;
 1779                 else
 1780                         *ap->a_eofflag = 0;
 1781         }
 1782         return (error);
 1783 }
 1784 
 1785 /*-
 1786  * a_vp   - pointer to the file's vnode
 1787  * a_bn   - logical block number within the file (cluster number for us)
 1788  * a_bop  - where to return the bufobj of the special file containing the fs
 1789  * a_bnp  - where to return the "physical" block number corresponding to a_bn
 1790  *          (relative to the special file; units are blocks of size DEV_BSIZE)
 1791  * a_runp - where to return the "run past" a_bn.  This is the count of logical
 1792  *          blocks whose physical blocks (together with a_bn's physical block)
 1793  *          are contiguous.
 1794  * a_runb - where to return the "run before" a_bn.
 1795  */
 1796 static int
 1797 msdosfs_bmap(ap)
 1798         struct vop_bmap_args /* {
 1799                 struct vnode *a_vp;
 1800                 daddr_t a_bn;
 1801                 struct bufobj **a_bop;
 1802                 daddr_t *a_bnp;
 1803                 int *a_runp;
 1804                 int *a_runb;
 1805         } */ *ap;
 1806 {
 1807         struct denode *dep;
 1808         struct mount *mp;
 1809         struct msdosfsmount *pmp;
 1810         struct vnode *vp;
 1811         daddr_t runbn;
 1812         u_long cn;
 1813         int bnpercn, error, maxio, maxrun, run;
 1814 
 1815         vp = ap->a_vp;
 1816         dep = VTODE(vp);
 1817         pmp = dep->de_pmp;
 1818         if (ap->a_bop != NULL)
 1819                 *ap->a_bop = &pmp->pm_devvp->v_bufobj;
 1820         if (ap->a_bnp == NULL)
 1821                 return (0);
 1822         if (ap->a_runp != NULL)
 1823                 *ap->a_runp = 0;
 1824         if (ap->a_runb != NULL)
 1825                 *ap->a_runb = 0;
 1826         cn = ap->a_bn;
 1827         if (cn != ap->a_bn)
 1828                 return (EFBIG);
 1829         error = pcbmap(dep, cn, ap->a_bnp, NULL, NULL);
 1830         if (error != 0 || (ap->a_runp == NULL && ap->a_runb == NULL))
 1831                 return (error);
 1832 
 1833         mp = vp->v_mount;
 1834         maxio = mp->mnt_iosize_max / mp->mnt_stat.f_iosize;
 1835         bnpercn = de_cn2bn(pmp, 1);
 1836         if (ap->a_runp != NULL) {
 1837                 maxrun = ulmin(maxio - 1, pmp->pm_maxcluster - cn);
 1838                 for (run = 1; run <= maxrun; run++) {
 1839                         if (pcbmap(dep, cn + run, &runbn, NULL, NULL) != 0 ||
 1840                             runbn != *ap->a_bnp + run * bnpercn)
 1841                                 break;
 1842                 }
 1843                 *ap->a_runp = run - 1;
 1844         }
 1845         if (ap->a_runb != NULL) {
 1846                 maxrun = ulmin(maxio - 1, cn);
 1847                 for (run = 1; run < maxrun; run++) {
 1848                         if (pcbmap(dep, cn - run, &runbn, NULL, NULL) != 0 ||
 1849                             runbn != *ap->a_bnp - run * bnpercn)
 1850                                 break;
 1851                 }
 1852                 *ap->a_runb = run - 1;
 1853         }
 1854         return (0);
 1855 }
 1856 
 1857 static int
 1858 msdosfs_strategy(ap)
 1859         struct vop_strategy_args /* {
 1860                 struct vnode *a_vp;
 1861                 struct buf *a_bp;
 1862         } */ *ap;
 1863 {
 1864         struct buf *bp = ap->a_bp;
 1865         struct denode *dep = VTODE(ap->a_vp);
 1866         struct bufobj *bo;
 1867         int error = 0;
 1868         daddr_t blkno;
 1869 
 1870         /*
 1871          * If we don't already know the filesystem relative block number
 1872          * then get it using pcbmap().  If pcbmap() returns the block
 1873          * number as -1 then we've got a hole in the file.  DOS filesystems
 1874          * don't allow files with holes, so we shouldn't ever see this.
 1875          */
 1876         if (bp->b_blkno == bp->b_lblkno) {
 1877                 error = pcbmap(dep, bp->b_lblkno, &blkno, 0, 0);
 1878                 bp->b_blkno = blkno;
 1879                 if (error) {
 1880                         bp->b_error = error;
 1881                         bp->b_ioflags |= BIO_ERROR;
 1882                         bufdone(bp);
 1883                         return (0);
 1884                 }
 1885                 if ((long)bp->b_blkno == -1)
 1886                         vfs_bio_clrbuf(bp);
 1887         }
 1888         if (bp->b_blkno == -1) {
 1889                 bufdone(bp);
 1890                 return (0);
 1891         }
 1892         /*
 1893          * Read/write the block from/to the disk that contains the desired
 1894          * file block.
 1895          */
 1896         bp->b_iooffset = dbtob(bp->b_blkno);
 1897         bo = dep->de_pmp->pm_bo;
 1898         BO_STRATEGY(bo, bp);
 1899         return (0);
 1900 }
 1901 
 1902 static int
 1903 msdosfs_print(ap)
 1904         struct vop_print_args /* {
 1905                 struct vnode *vp;
 1906         } */ *ap;
 1907 {
 1908         struct denode *dep = VTODE(ap->a_vp);
 1909 
 1910         printf("\tstartcluster %lu, dircluster %lu, diroffset %lu, ",
 1911                dep->de_StartCluster, dep->de_dirclust, dep->de_diroffset);
 1912         printf("on dev %s\n", devtoname(dep->de_dev));
 1913         return (0);
 1914 }
 1915 
 1916 static int
 1917 msdosfs_pathconf(ap)
 1918         struct vop_pathconf_args /* {
 1919                 struct vnode *a_vp;
 1920                 int a_name;
 1921                 int *a_retval;
 1922         } */ *ap;
 1923 {
 1924         struct msdosfsmount *pmp = VTODE(ap->a_vp)->de_pmp;
 1925 
 1926         switch (ap->a_name) {
 1927         case _PC_LINK_MAX:
 1928                 *ap->a_retval = 1;
 1929                 return (0);
 1930         case _PC_NAME_MAX:
 1931                 *ap->a_retval = pmp->pm_flags & MSDOSFSMNT_LONGNAME ? WIN_MAXLEN : 12;
 1932                 return (0);
 1933         case _PC_PATH_MAX:
 1934                 *ap->a_retval = PATH_MAX;
 1935                 return (0);
 1936         case _PC_CHOWN_RESTRICTED:
 1937                 *ap->a_retval = 1;
 1938                 return (0);
 1939         case _PC_NO_TRUNC:
 1940                 *ap->a_retval = 0;
 1941                 return (0);
 1942         default:
 1943                 return (EINVAL);
 1944         }
 1945         /* NOTREACHED */
 1946 }
 1947 
 1948 static int
 1949 msdosfs_vptofh(ap)
 1950         struct vop_vptofh_args /* {
 1951                 struct vnode *a_vp;
 1952                 struct fid *a_fhp;
 1953         } */ *ap;
 1954 {
 1955         struct denode *dep;
 1956         struct defid *defhp;
 1957 
 1958         dep = VTODE(ap->a_vp);
 1959         defhp = (struct defid *)ap->a_fhp;
 1960         defhp->defid_len = sizeof(struct defid);
 1961         defhp->defid_dirclust = dep->de_dirclust;
 1962         defhp->defid_dirofs = dep->de_diroffset;
 1963         /* defhp->defid_gen = dep->de_gen; */
 1964         return (0);
 1965 }
 1966 
 1967 /* Global vfs data structures for msdosfs */
 1968 struct vop_vector msdosfs_vnodeops = {
 1969         .vop_default =          &default_vnodeops,
 1970 
 1971         .vop_access =           msdosfs_access,
 1972         .vop_bmap =             msdosfs_bmap,
 1973         .vop_cachedlookup =     msdosfs_lookup,
 1974         .vop_open =             msdosfs_open,
 1975         .vop_close =            msdosfs_close,
 1976         .vop_create =           msdosfs_create,
 1977         .vop_fsync =            msdosfs_fsync,
 1978         .vop_getattr =          msdosfs_getattr,
 1979         .vop_inactive =         msdosfs_inactive,
 1980         .vop_link =             msdosfs_link,
 1981         .vop_lookup =           vfs_cache_lookup,
 1982         .vop_mkdir =            msdosfs_mkdir,
 1983         .vop_mknod =            msdosfs_mknod,
 1984         .vop_pathconf =         msdosfs_pathconf,
 1985         .vop_print =            msdosfs_print,
 1986         .vop_read =             msdosfs_read,
 1987         .vop_readdir =          msdosfs_readdir,
 1988         .vop_reclaim =          msdosfs_reclaim,
 1989         .vop_remove =           msdosfs_remove,
 1990         .vop_rename =           msdosfs_rename,
 1991         .vop_rmdir =            msdosfs_rmdir,
 1992         .vop_setattr =          msdosfs_setattr,
 1993         .vop_strategy =         msdosfs_strategy,
 1994         .vop_symlink =          msdosfs_symlink,
 1995         .vop_write =            msdosfs_write,
 1996         .vop_vptofh =           msdosfs_vptofh,
 1997 };

Cache object: d68df1883683f93e3c6206ef02042a52


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