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/8.0/sys/fs/msdosfs/msdosfs_vnops.c 193924 2009-06-10 14:24:31Z kib $ */
    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_pmp = pdep->de_pmp;
  184         ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE;
  185         getnanotime(&ts);
  186         DETIMES(&ndirent, &ts, &ts, &ts);
  187         error = createde(&ndirent, pdep, &dep, cnp);
  188         if (error)
  189                 goto bad;
  190         *ap->a_vpp = DETOV(dep);
  191         return (0);
  192 
  193 bad:
  194         return (error);
  195 }
  196 
  197 static int
  198 msdosfs_mknod(ap)
  199         struct vop_mknod_args /* {
  200                 struct vnode *a_dvp;
  201                 struct vnode **a_vpp;
  202                 struct componentname *a_cnp;
  203                 struct vattr *a_vap;
  204         } */ *ap;
  205 {
  206 
  207     return (EINVAL);
  208 }
  209 
  210 static int
  211 msdosfs_open(ap)
  212         struct vop_open_args /* {
  213                 struct vnode *a_vp;
  214                 int a_mode;
  215                 struct ucred *a_cred;
  216                 struct thread *a_td;
  217                 struct file *a_fp;
  218         } */ *ap;
  219 {
  220         struct denode *dep = VTODE(ap->a_vp);
  221         vnode_create_vobject(ap->a_vp, dep->de_FileSize, ap->a_td);
  222         return 0;
  223 }
  224 
  225 static int
  226 msdosfs_close(ap)
  227         struct vop_close_args /* {
  228                 struct vnode *a_vp;
  229                 int a_fflag;
  230                 struct ucred *a_cred;
  231                 struct thread *a_td;
  232         } */ *ap;
  233 {
  234         struct vnode *vp = ap->a_vp;
  235         struct denode *dep = VTODE(vp);
  236         struct timespec ts;
  237 
  238         VI_LOCK(vp);
  239         if (vp->v_usecount > 1) {
  240                 getnanotime(&ts);
  241                 DETIMES(dep, &ts, &ts, &ts);
  242         }
  243         VI_UNLOCK(vp);
  244         return 0;
  245 }
  246 
  247 static int
  248 msdosfs_access(ap)
  249         struct vop_access_args /* {
  250                 struct vnode *a_vp;
  251                 accmode_t a_accmode;
  252                 struct ucred *a_cred;
  253                 struct thread *a_td;
  254         } */ *ap;
  255 {
  256         struct vnode *vp = ap->a_vp;
  257         struct denode *dep = VTODE(ap->a_vp);
  258         struct msdosfsmount *pmp = dep->de_pmp;
  259         mode_t file_mode;
  260         accmode_t accmode = ap->a_accmode;
  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 (accmode & 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_accmode, 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         } */ *ap;
  293 {
  294         struct denode *dep = VTODE(ap->a_vp);
  295         struct msdosfsmount *pmp = dep->de_pmp;
  296         struct vattr *vap = ap->a_vap;
  297         mode_t mode;
  298         struct timespec ts;
  299         u_long dirsperblk = pmp->pm_BytesPerSec / sizeof(struct direntry);
  300         uint64_t fileid;
  301 
  302         getnanotime(&ts);
  303         DETIMES(dep, &ts, &ts, &ts);
  304         vap->va_fsid = dev2udev(pmp->pm_dev);
  305         /*
  306          * The following computation of the fileid must be the same as that
  307          * used in msdosfs_readdir() to compute d_fileno. If not, pwd
  308          * doesn't work.
  309          */
  310         if (dep->de_Attributes & ATTR_DIRECTORY) {
  311                 fileid = (uint64_t)cntobn(pmp, dep->de_StartCluster) *
  312                     dirsperblk;
  313                 if (dep->de_StartCluster == MSDOSFSROOT)
  314                         fileid = 1;
  315         } else {
  316                 fileid = (uint64_t)cntobn(pmp, dep->de_dirclust) *
  317                     dirsperblk;
  318                 if (dep->de_dirclust == MSDOSFSROOT)
  319                         fileid = (uint64_t)roottobn(pmp, 0) * dirsperblk;
  320                 fileid += (uoff_t)dep->de_diroffset / sizeof(struct direntry);
  321         }
  322 
  323         if (pmp->pm_flags & MSDOSFS_LARGEFS)
  324                 vap->va_fileid = msdosfs_fileno_map(pmp->pm_mountp, fileid);
  325         else
  326                 vap->va_fileid = (long)fileid;
  327 
  328         if ((dep->de_Attributes & ATTR_READONLY) == 0)
  329                 mode = S_IRWXU|S_IRWXG|S_IRWXO;
  330         else
  331                 mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH;
  332         vap->va_mode = mode & 
  333             (ap->a_vp->v_type == VDIR ? pmp->pm_dirmask : pmp->pm_mask);
  334         vap->va_uid = pmp->pm_uid;
  335         vap->va_gid = pmp->pm_gid;
  336         vap->va_nlink = 1;
  337         vap->va_rdev = NODEV;
  338         vap->va_size = dep->de_FileSize;
  339         fattime2timespec(dep->de_MDate, dep->de_MTime, 0, 0, &vap->va_mtime);
  340         vap->va_ctime = vap->va_mtime;
  341         if (pmp->pm_flags & MSDOSFSMNT_LONGNAME) {
  342                 fattime2timespec(dep->de_ADate, 0, 0, 0, &vap->va_atime);
  343                 fattime2timespec(dep->de_CDate, dep->de_CTime, dep->de_CHun,
  344                     0, &vap->va_birthtime);
  345         } else {
  346                 vap->va_atime = vap->va_mtime;
  347                 vap->va_birthtime.tv_sec = -1;
  348                 vap->va_birthtime.tv_nsec = 0;
  349         }
  350         vap->va_flags = 0;
  351         if ((dep->de_Attributes & ATTR_ARCHIVE) == 0)
  352                 vap->va_flags |= SF_ARCHIVED;
  353         vap->va_gen = 0;
  354         vap->va_blocksize = pmp->pm_bpcluster;
  355         vap->va_bytes =
  356             (dep->de_FileSize + pmp->pm_crbomask) & ~pmp->pm_crbomask;
  357         vap->va_type = ap->a_vp->v_type;
  358         vap->va_filerev = dep->de_modrev;
  359         return (0);
  360 }
  361 
  362 static int
  363 msdosfs_setattr(ap)
  364         struct vop_setattr_args /* {
  365                 struct vnode *a_vp;
  366                 struct vattr *a_vap;
  367                 struct ucred *a_cred;
  368         } */ *ap;
  369 {
  370         struct vnode *vp = ap->a_vp;
  371         struct denode *dep = VTODE(ap->a_vp);
  372         struct msdosfsmount *pmp = dep->de_pmp;
  373         struct vattr *vap = ap->a_vap;
  374         struct ucred *cred = ap->a_cred;
  375         struct thread *td = curthread;
  376         int error = 0;
  377 
  378 #ifdef MSDOSFS_DEBUG
  379         printf("msdosfs_setattr(): vp %p, vap %p, cred %p\n",
  380             ap->a_vp, vap, cred);
  381 #endif
  382 
  383         /*
  384          * Check for unsettable attributes.
  385          */
  386         if ((vap->va_type != VNON) || (vap->va_nlink != VNOVAL) ||
  387             (vap->va_fsid != VNOVAL) || (vap->va_fileid != VNOVAL) ||
  388             (vap->va_blocksize != VNOVAL) || (vap->va_rdev != VNOVAL) ||
  389             (vap->va_bytes != VNOVAL) || (vap->va_gen != VNOVAL)) {
  390 #ifdef MSDOSFS_DEBUG
  391                 printf("msdosfs_setattr(): returning EINVAL\n");
  392                 printf("    va_type %d, va_nlink %x, va_fsid %lx, va_fileid %lx\n",
  393                     vap->va_type, vap->va_nlink, vap->va_fsid, vap->va_fileid);
  394                 printf("    va_blocksize %lx, va_rdev %x, va_bytes %qx, va_gen %lx\n",
  395                     vap->va_blocksize, vap->va_rdev, vap->va_bytes, vap->va_gen);
  396                 printf("    va_uid %x, va_gid %x\n",
  397                     vap->va_uid, vap->va_gid);
  398 #endif
  399                 return (EINVAL);
  400         }
  401         if (vap->va_flags != VNOVAL) {
  402                 if (vp->v_mount->mnt_flag & MNT_RDONLY)
  403                         return (EROFS);
  404                 if (cred->cr_uid != pmp->pm_uid) {
  405                         error = priv_check_cred(cred, PRIV_VFS_ADMIN, 0);
  406                         if (error)
  407                                 return (error);
  408                 }
  409                 /*
  410                  * We are very inconsistent about handling unsupported
  411                  * attributes.  We ignored the access time and the
  412                  * read and execute bits.  We were strict for the other
  413                  * attributes.
  414                  *
  415                  * Here we are strict, stricter than ufs in not allowing
  416                  * users to attempt to set SF_SETTABLE bits or anyone to
  417                  * set unsupported bits.  However, we ignore attempts to
  418                  * set ATTR_ARCHIVE for directories `cp -pr' from a more
  419                  * sensible filesystem attempts it a lot.
  420                  */
  421                 if (vap->va_flags & SF_SETTABLE) {
  422                         error = priv_check_cred(cred, PRIV_VFS_SYSFLAGS, 0);
  423                         if (error)
  424                                 return (error);
  425                 }
  426                 if (vap->va_flags & ~SF_ARCHIVED)
  427                         return EOPNOTSUPP;
  428                 if (vap->va_flags & SF_ARCHIVED)
  429                         dep->de_Attributes &= ~ATTR_ARCHIVE;
  430                 else if (!(dep->de_Attributes & ATTR_DIRECTORY))
  431                         dep->de_Attributes |= ATTR_ARCHIVE;
  432                 dep->de_flag |= DE_MODIFIED;
  433         }
  434 
  435         if (vap->va_uid != (uid_t)VNOVAL || vap->va_gid != (gid_t)VNOVAL) {
  436                 uid_t uid;
  437                 gid_t gid;
  438 
  439                 if (vp->v_mount->mnt_flag & MNT_RDONLY)
  440                         return (EROFS);
  441                 uid = vap->va_uid;
  442                 if (uid == (uid_t)VNOVAL)
  443                         uid = pmp->pm_uid;
  444                 gid = vap->va_gid;
  445                 if (gid == (gid_t)VNOVAL)
  446                         gid = pmp->pm_gid;
  447                 if (cred->cr_uid != pmp->pm_uid || uid != pmp->pm_uid ||
  448                     (gid != pmp->pm_gid && !groupmember(gid, cred))) {
  449                         error = priv_check_cred(cred, PRIV_VFS_CHOWN, 0);
  450                         if (error)
  451                                 return (error);
  452                 }
  453                 if (uid != pmp->pm_uid || gid != pmp->pm_gid)
  454                         return EINVAL;
  455         }
  456 
  457         if (vap->va_size != VNOVAL) {
  458                 switch (vp->v_type) {
  459                 case VDIR:
  460                         return (EISDIR);
  461                 case VREG:
  462                         /*
  463                          * Truncation is only supported for regular files,
  464                          * Disallow it if the filesystem is read-only.
  465                          */
  466                         if (vp->v_mount->mnt_flag & MNT_RDONLY)
  467                                 return (EROFS);
  468                         break;
  469                 default:
  470                         /*
  471                          * According to POSIX, the result is unspecified
  472                          * for file types other than regular files,
  473                          * directories and shared memory objects.  We
  474                          * don't support any file types except regular
  475                          * files and directories in this file system, so
  476                          * this (default) case is unreachable and can do
  477                          * anything.  Keep falling through to detrunc()
  478                          * for now.
  479                          */
  480                         break;
  481                 }
  482                 error = detrunc(dep, vap->va_size, 0, cred, td);
  483                 if (error)
  484                         return error;
  485         }
  486         if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) {
  487                 if (vp->v_mount->mnt_flag & MNT_RDONLY)
  488                         return (EROFS);
  489                 if (vap->va_vaflags & VA_UTIMES_NULL) {
  490                         error = VOP_ACCESS(vp, VADMIN, cred, td); 
  491                         if (error)
  492                                 error = VOP_ACCESS(vp, VWRITE, cred, td);
  493                 } else
  494                         error = VOP_ACCESS(vp, VADMIN, cred, td);
  495                 if (vp->v_type != VDIR) {
  496                         if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95) == 0 &&
  497                             vap->va_atime.tv_sec != VNOVAL) {
  498                                 dep->de_flag &= ~DE_ACCESS;
  499                                 timespec2fattime(&vap->va_atime, 0,
  500                                     &dep->de_ADate, NULL, NULL);
  501                         }
  502                         if (vap->va_mtime.tv_sec != VNOVAL) {
  503                                 dep->de_flag &= ~DE_UPDATE;
  504                                 timespec2fattime(&vap->va_mtime, 0,
  505                                     &dep->de_MDate, &dep->de_MTime, NULL);
  506                         }
  507                         dep->de_Attributes |= ATTR_ARCHIVE;
  508                         dep->de_flag |= DE_MODIFIED;
  509                 }
  510         }
  511         /*
  512          * DOS files only have the ability to have their writability
  513          * attribute set, so we use the owner write bit to set the readonly
  514          * attribute.
  515          */
  516         if (vap->va_mode != (mode_t)VNOVAL) {
  517                 if (vp->v_mount->mnt_flag & MNT_RDONLY)
  518                         return (EROFS);
  519                 if (cred->cr_uid != pmp->pm_uid) {
  520                         error = priv_check_cred(cred, PRIV_VFS_ADMIN, 0);
  521                         if (error)
  522                                 return (error);
  523                 }
  524                 if (vp->v_type != VDIR) {
  525                         /* We ignore the read and execute bits. */
  526                         if (vap->va_mode & VWRITE)
  527                                 dep->de_Attributes &= ~ATTR_READONLY;
  528                         else
  529                                 dep->de_Attributes |= ATTR_READONLY;
  530                         dep->de_Attributes |= ATTR_ARCHIVE;
  531                         dep->de_flag |= DE_MODIFIED;
  532                 }
  533         }
  534         return (deupdat(dep, 0));
  535 }
  536 
  537 static int
  538 msdosfs_read(ap)
  539         struct vop_read_args /* {
  540                 struct vnode *a_vp;
  541                 struct uio *a_uio;
  542                 int a_ioflag;
  543                 struct ucred *a_cred;
  544         } */ *ap;
  545 {
  546         int error = 0;
  547         int blsize;
  548         int isadir;
  549         int orig_resid;
  550         u_int n;
  551         u_long diff;
  552         u_long on;
  553         daddr_t lbn;
  554         daddr_t rablock;
  555         int rasize;
  556         int seqcount;
  557         struct buf *bp;
  558         struct vnode *vp = ap->a_vp;
  559         struct denode *dep = VTODE(vp);
  560         struct msdosfsmount *pmp = dep->de_pmp;
  561         struct uio *uio = ap->a_uio;
  562 
  563         /*
  564          * If they didn't ask for any data, then we are done.
  565          */
  566         orig_resid = uio->uio_resid;
  567         if (orig_resid == 0)
  568                 return (0);
  569 
  570         /*
  571          * The caller is supposed to ensure that
  572          * uio->uio_offset >= 0 and uio->uio_resid >= 0.
  573          * We don't need to check for large offsets as in ffs because
  574          * dep->de_FileSize <= DOS_FILESIZE_MAX < OFF_MAX, so large
  575          * offsets cannot cause overflow even in theory.
  576          */
  577 
  578         seqcount = ap->a_ioflag >> IO_SEQSHIFT;
  579 
  580         isadir = dep->de_Attributes & ATTR_DIRECTORY;
  581         do {
  582                 if (uio->uio_offset >= dep->de_FileSize)
  583                         break;
  584                 lbn = de_cluster(pmp, uio->uio_offset);
  585                 rablock = lbn + 1;
  586                 blsize = pmp->pm_bpcluster;
  587                 on = uio->uio_offset & pmp->pm_crbomask;
  588                 /*
  589                  * If we are operating on a directory file then be sure to
  590                  * do i/o with the vnode for the filesystem instead of the
  591                  * vnode for the directory.
  592                  */
  593                 if (isadir) {
  594                         /* convert cluster # to block # */
  595                         error = pcbmap(dep, lbn, &lbn, 0, &blsize);
  596                         if (error == E2BIG) {
  597                                 error = EINVAL;
  598                                 break;
  599                         } else if (error)
  600                                 break;
  601                         error = bread(pmp->pm_devvp, lbn, blsize, NOCRED, &bp);
  602                 } else if (de_cn2off(pmp, rablock) >= dep->de_FileSize) {
  603                         error = bread(vp, lbn, blsize, NOCRED, &bp);
  604                 } else if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) {
  605                         error = cluster_read(vp, dep->de_FileSize, lbn, blsize,
  606                             NOCRED, on + uio->uio_resid, seqcount, &bp);
  607                 } else if (seqcount > 1) {
  608                         rasize = blsize;
  609                         error = breadn(vp, lbn,
  610                             blsize, &rablock, &rasize, 1, NOCRED, &bp);
  611                 } else {
  612                         error = bread(vp, lbn, blsize, NOCRED, &bp);
  613                 }
  614                 if (error) {
  615                         brelse(bp);
  616                         break;
  617                 }
  618                 diff = pmp->pm_bpcluster - on;
  619                 n = diff > uio->uio_resid ? uio->uio_resid : diff;
  620                 diff = dep->de_FileSize - uio->uio_offset;
  621                 if (diff < n)
  622                         n = diff;
  623                 diff = blsize - bp->b_resid;
  624                 if (diff < n)
  625                         n = diff;
  626                 error = uiomove(bp->b_data + on, (int) n, uio);
  627                 brelse(bp);
  628         } while (error == 0 && uio->uio_resid > 0 && n != 0);
  629         if (!isadir && (error == 0 || uio->uio_resid != orig_resid) &&
  630             (vp->v_mount->mnt_flag & MNT_NOATIME) == 0)
  631                 dep->de_flag |= DE_ACCESS;
  632         return (error);
  633 }
  634 
  635 /*
  636  * Write data to a file or directory.
  637  */
  638 static int
  639 msdosfs_write(ap)
  640         struct vop_write_args /* {
  641                 struct vnode *a_vp;
  642                 struct uio *a_uio;
  643                 int a_ioflag;
  644                 struct ucred *a_cred;
  645         } */ *ap;
  646 {
  647         int n;
  648         int croffset;
  649         int resid;
  650         u_long osize;
  651         int error = 0;
  652         u_long count;
  653         int seqcount;
  654         daddr_t bn, lastcn;
  655         struct buf *bp;
  656         int ioflag = ap->a_ioflag;
  657         struct uio *uio = ap->a_uio;
  658         struct thread *td = uio->uio_td;
  659         struct vnode *vp = ap->a_vp;
  660         struct vnode *thisvp;
  661         struct denode *dep = VTODE(vp);
  662         struct msdosfsmount *pmp = dep->de_pmp;
  663         struct ucred *cred = ap->a_cred;
  664 
  665 #ifdef MSDOSFS_DEBUG
  666         printf("msdosfs_write(vp %p, uio %p, ioflag %x, cred %p\n",
  667             vp, uio, ioflag, cred);
  668         printf("msdosfs_write(): diroff %lu, dirclust %lu, startcluster %lu\n",
  669             dep->de_diroffset, dep->de_dirclust, dep->de_StartCluster);
  670 #endif
  671 
  672         switch (vp->v_type) {
  673         case VREG:
  674                 if (ioflag & IO_APPEND)
  675                         uio->uio_offset = dep->de_FileSize;
  676                 thisvp = vp;
  677                 break;
  678         case VDIR:
  679                 return EISDIR;
  680         default:
  681                 panic("msdosfs_write(): bad file type");
  682         }
  683 
  684         /*
  685          * This is needed (unlike in ffs_write()) because we extend the
  686          * file outside of the loop but we don't want to extend the file
  687          * for writes of 0 bytes.
  688          */
  689         if (uio->uio_resid == 0)
  690                 return (0);
  691 
  692         /*
  693          * The caller is supposed to ensure that
  694          * uio->uio_offset >= 0 and uio->uio_resid >= 0.
  695          */
  696         if ((uoff_t)uio->uio_offset + uio->uio_resid > DOS_FILESIZE_MAX)
  697                 return (EFBIG);
  698 
  699         /*
  700          * If they've exceeded their filesize limit, tell them about it.
  701          */
  702         if (td != NULL) {
  703                 PROC_LOCK(td->td_proc);
  704                 if ((uoff_t)uio->uio_offset + uio->uio_resid >
  705                     lim_cur(td->td_proc, RLIMIT_FSIZE)) {
  706                         psignal(td->td_proc, SIGXFSZ);
  707                         PROC_UNLOCK(td->td_proc);
  708                         return (EFBIG);
  709                 }
  710                 PROC_UNLOCK(td->td_proc);
  711         }
  712 
  713         /*
  714          * If the offset we are starting the write at is beyond the end of
  715          * the file, then they've done a seek.  Unix filesystems allow
  716          * files with holes in them, DOS doesn't so we must fill the hole
  717          * with zeroed blocks.
  718          */
  719         if (uio->uio_offset > dep->de_FileSize) {
  720                 error = deextend(dep, uio->uio_offset, cred);
  721                 if (error)
  722                         return (error);
  723         }
  724 
  725         /*
  726          * Remember some values in case the write fails.
  727          */
  728         resid = uio->uio_resid;
  729         osize = dep->de_FileSize;
  730 
  731         /*
  732          * If we write beyond the end of the file, extend it to its ultimate
  733          * size ahead of the time to hopefully get a contiguous area.
  734          */
  735         if (uio->uio_offset + resid > osize) {
  736                 count = de_clcount(pmp, uio->uio_offset + resid) -
  737                         de_clcount(pmp, osize);
  738                 error = extendfile(dep, count, NULL, NULL, 0);
  739                 if (error &&  (error != ENOSPC || (ioflag & IO_UNIT)))
  740                         goto errexit;
  741                 lastcn = dep->de_fc[FC_LASTFC].fc_frcn;
  742         } else
  743                 lastcn = de_clcount(pmp, osize) - 1;
  744 
  745         seqcount = ioflag >> IO_SEQSHIFT;
  746         do {
  747                 if (de_cluster(pmp, uio->uio_offset) > lastcn) {
  748                         error = ENOSPC;
  749                         break;
  750                 }
  751 
  752                 croffset = uio->uio_offset & pmp->pm_crbomask;
  753                 n = min(uio->uio_resid, pmp->pm_bpcluster - croffset);
  754                 if (uio->uio_offset + n > dep->de_FileSize) {
  755                         dep->de_FileSize = uio->uio_offset + n;
  756                         /* The object size needs to be set before buffer is allocated */
  757                         vnode_pager_setsize(vp, dep->de_FileSize);
  758                 }
  759 
  760                 bn = de_cluster(pmp, uio->uio_offset);
  761                 if ((uio->uio_offset & pmp->pm_crbomask) == 0
  762                     && (de_cluster(pmp, uio->uio_offset + uio->uio_resid)
  763                         > de_cluster(pmp, uio->uio_offset)
  764                         || uio->uio_offset + uio->uio_resid >= dep->de_FileSize)) {
  765                         /*
  766                          * If either the whole cluster gets written,
  767                          * or we write the cluster from its start beyond EOF,
  768                          * then no need to read data from disk.
  769                          */
  770                         bp = getblk(thisvp, bn, pmp->pm_bpcluster, 0, 0, 0);
  771                         vfs_bio_clrbuf(bp);
  772                         /*
  773                          * Do the bmap now, since pcbmap needs buffers
  774                          * for the fat table. (see msdosfs_strategy)
  775                          */
  776                         if (bp->b_blkno == bp->b_lblkno) {
  777                                 error = pcbmap(dep, bp->b_lblkno, &bn, 0, 0);
  778                                 if (error)
  779                                         bp->b_blkno = -1;
  780                                 else
  781                                         bp->b_blkno = bn;
  782                         }
  783                         if (bp->b_blkno == -1) {
  784                                 brelse(bp);
  785                                 if (!error)
  786                                         error = EIO;            /* XXX */
  787                                 break;
  788                         }
  789                 } else {
  790                         /*
  791                          * The block we need to write into exists, so read it in.
  792                          */
  793                         error = bread(thisvp, bn, pmp->pm_bpcluster, cred, &bp);
  794                         if (error) {
  795                                 brelse(bp);
  796                                 break;
  797                         }
  798                 }
  799 
  800                 /*
  801                  * Should these vnode_pager_* functions be done on dir
  802                  * files?
  803                  */
  804 
  805                 /*
  806                  * Copy the data from user space into the buf header.
  807                  */
  808                 error = uiomove(bp->b_data + croffset, n, uio);
  809                 if (error) {
  810                         brelse(bp);
  811                         break;
  812                 }
  813 
  814                 /* Prepare for clustered writes in some else clauses. */
  815                 if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0)
  816                         bp->b_flags |= B_CLUSTEROK;
  817 
  818                 /*
  819                  * If IO_SYNC, then each buffer is written synchronously.
  820                  * Otherwise, if we have a severe page deficiency then
  821                  * write the buffer asynchronously.  Otherwise, if on a
  822                  * cluster boundary then write the buffer asynchronously,
  823                  * combining it with contiguous clusters if permitted and
  824                  * possible, since we don't expect more writes into this
  825                  * buffer soon.  Otherwise, do a delayed write because we
  826                  * expect more writes into this buffer soon.
  827                  */
  828                 if (ioflag & IO_SYNC)
  829                         (void)bwrite(bp);
  830                 else if (vm_page_count_severe() || buf_dirty_count_severe())
  831                         bawrite(bp);
  832                 else if (n + croffset == pmp->pm_bpcluster) {
  833                         if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0)
  834                                 cluster_write(vp, bp, dep->de_FileSize,
  835                                     seqcount);
  836                         else
  837                                 bawrite(bp);
  838                 } else
  839                         bdwrite(bp);
  840                 dep->de_flag |= DE_UPDATE;
  841         } while (error == 0 && uio->uio_resid > 0);
  842 
  843         /*
  844          * If the write failed and they want us to, truncate the file back
  845          * to the size it was before the write was attempted.
  846          */
  847 errexit:
  848         if (error) {
  849                 if (ioflag & IO_UNIT) {
  850                         detrunc(dep, osize, ioflag & IO_SYNC, NOCRED, NULL);
  851                         uio->uio_offset -= resid - uio->uio_resid;
  852                         uio->uio_resid = resid;
  853                 } else {
  854                         detrunc(dep, dep->de_FileSize, ioflag & IO_SYNC, NOCRED, NULL);
  855                         if (uio->uio_resid != resid)
  856                                 error = 0;
  857                 }
  858         } else if (ioflag & IO_SYNC)
  859                 error = deupdat(dep, 1);
  860         return (error);
  861 }
  862 
  863 /*
  864  * Flush the blocks of a file to disk.
  865  *
  866  * This function is worthless for vnodes that represent directories. Maybe we
  867  * could just do a sync if they try an fsync on a directory file.
  868  */
  869 static int
  870 msdosfs_fsync(ap)
  871         struct vop_fsync_args /* {
  872                 struct vnode *a_vp;
  873                 struct ucred *a_cred;
  874                 int a_waitfor;
  875                 struct thread *a_td;
  876         } */ *ap;
  877 {
  878 
  879         vop_stdfsync(ap);
  880         return (deupdat(VTODE(ap->a_vp), ap->a_waitfor == MNT_WAIT));
  881 }
  882 
  883 static int
  884 msdosfs_remove(ap)
  885         struct vop_remove_args /* {
  886                 struct vnode *a_dvp;
  887                 struct vnode *a_vp;
  888                 struct componentname *a_cnp;
  889         } */ *ap;
  890 {
  891         struct denode *dep = VTODE(ap->a_vp);
  892         struct denode *ddep = VTODE(ap->a_dvp);
  893         int error;
  894 
  895         if (ap->a_vp->v_type == VDIR)
  896                 error = EPERM;
  897         else
  898                 error = removede(ddep, dep);
  899 #ifdef MSDOSFS_DEBUG
  900         printf("msdosfs_remove(), dep %p, v_usecount %d\n", dep, ap->a_vp->v_usecount);
  901 #endif
  902         return (error);
  903 }
  904 
  905 /*
  906  * DOS filesystems don't know what links are.
  907  */
  908 static int
  909 msdosfs_link(ap)
  910         struct vop_link_args /* {
  911                 struct vnode *a_tdvp;
  912                 struct vnode *a_vp;
  913                 struct componentname *a_cnp;
  914         } */ *ap;
  915 {
  916         return (EOPNOTSUPP);
  917 }
  918 
  919 /*
  920  * Renames on files require moving the denode to a new hash queue since the
  921  * denode's location is used to compute which hash queue to put the file
  922  * in. Unless it is a rename in place.  For example "mv a b".
  923  *
  924  * What follows is the basic algorithm:
  925  *
  926  * if (file move) {
  927  *      if (dest file exists) {
  928  *              remove dest file
  929  *      }
  930  *      if (dest and src in same directory) {
  931  *              rewrite name in existing directory slot
  932  *      } else {
  933  *              write new entry in dest directory
  934  *              update offset and dirclust in denode
  935  *              move denode to new hash chain
  936  *              clear old directory entry
  937  *      }
  938  * } else {
  939  *      directory move
  940  *      if (dest directory exists) {
  941  *              if (dest is not empty) {
  942  *                      return ENOTEMPTY
  943  *              }
  944  *              remove dest directory
  945  *      }
  946  *      if (dest and src in same directory) {
  947  *              rewrite name in existing entry
  948  *      } else {
  949  *              be sure dest is not a child of src directory
  950  *              write entry in dest directory
  951  *              update "." and ".." in moved directory
  952  *              clear old directory entry for moved directory
  953  *      }
  954  * }
  955  *
  956  * On entry:
  957  *      source's parent directory is unlocked
  958  *      source file or directory is unlocked
  959  *      destination's parent directory is locked
  960  *      destination file or directory is locked if it exists
  961  *
  962  * On exit:
  963  *      all denodes should be released
  964  */
  965 static int
  966 msdosfs_rename(ap)
  967         struct vop_rename_args /* {
  968                 struct vnode *a_fdvp;
  969                 struct vnode *a_fvp;
  970                 struct componentname *a_fcnp;
  971                 struct vnode *a_tdvp;
  972                 struct vnode *a_tvp;
  973                 struct componentname *a_tcnp;
  974         } */ *ap;
  975 {
  976         struct vnode *tdvp = ap->a_tdvp;
  977         struct vnode *fvp = ap->a_fvp;
  978         struct vnode *fdvp = ap->a_fdvp;
  979         struct vnode *tvp = ap->a_tvp;
  980         struct componentname *tcnp = ap->a_tcnp;
  981         struct componentname *fcnp = ap->a_fcnp;
  982         struct denode *ip, *xp, *dp, *zp;
  983         u_char toname[12], oldname[11];
  984         u_long from_diroffset, to_diroffset;
  985         u_char to_count;
  986         int doingdirectory = 0, newparent = 0;
  987         int error;
  988         u_long cn;
  989         daddr_t bn;
  990         struct denode *fddep;   /* from file's parent directory  */
  991         struct msdosfsmount *pmp;
  992         struct direntry *dotdotp;
  993         struct buf *bp;
  994 
  995         fddep = VTODE(ap->a_fdvp);
  996         pmp = fddep->de_pmp;
  997 
  998         pmp = VFSTOMSDOSFS(fdvp->v_mount);
  999 
 1000 #ifdef DIAGNOSTIC
 1001         if ((tcnp->cn_flags & HASBUF) == 0 ||
 1002             (fcnp->cn_flags & HASBUF) == 0)
 1003                 panic("msdosfs_rename: no name");
 1004 #endif
 1005         /*
 1006          * Check for cross-device rename.
 1007          */
 1008         if (fvp->v_mount != tdvp->v_mount ||
 1009             (tvp && fvp->v_mount != tvp->v_mount)) {
 1010                 error = EXDEV;
 1011 abortit:
 1012                 if (tdvp == tvp)
 1013                         vrele(tdvp);
 1014                 else
 1015                         vput(tdvp);
 1016                 if (tvp)
 1017                         vput(tvp);
 1018                 vrele(fdvp);
 1019                 vrele(fvp);
 1020                 return (error);
 1021         }
 1022 
 1023         /*
 1024          * If source and dest are the same, do nothing.
 1025          */
 1026         if (tvp == fvp) {
 1027                 error = 0;
 1028                 goto abortit;
 1029         }
 1030 
 1031         error = vn_lock(fvp, LK_EXCLUSIVE);
 1032         if (error)
 1033                 goto abortit;
 1034         dp = VTODE(fdvp);
 1035         ip = VTODE(fvp);
 1036 
 1037         /*
 1038          * Be sure we are not renaming ".", "..", or an alias of ".". This
 1039          * leads to a crippled directory tree.  It's pretty tough to do a
 1040          * "ls" or "pwd" with the "." directory entry missing, and "cd .."
 1041          * doesn't work if the ".." entry is missing.
 1042          */
 1043         if (ip->de_Attributes & ATTR_DIRECTORY) {
 1044                 /*
 1045                  * Avoid ".", "..", and aliases of "." for obvious reasons.
 1046                  */
 1047                 if ((fcnp->cn_namelen == 1 && fcnp->cn_nameptr[0] == '.') ||
 1048                     dp == ip ||
 1049                     (fcnp->cn_flags & ISDOTDOT) ||
 1050                     (tcnp->cn_flags & ISDOTDOT) ||
 1051                     (ip->de_flag & DE_RENAME)) {
 1052                         VOP_UNLOCK(fvp, 0);
 1053                         error = EINVAL;
 1054                         goto abortit;
 1055                 }
 1056                 ip->de_flag |= DE_RENAME;
 1057                 doingdirectory++;
 1058         }
 1059 
 1060         /*
 1061          * When the target exists, both the directory
 1062          * and target vnodes are returned locked.
 1063          */
 1064         dp = VTODE(tdvp);
 1065         xp = tvp ? VTODE(tvp) : NULL;
 1066         /*
 1067          * Remember direntry place to use for destination
 1068          */
 1069         to_diroffset = dp->de_fndoffset;
 1070         to_count = dp->de_fndcnt;
 1071 
 1072         /*
 1073          * If ".." must be changed (ie the directory gets a new
 1074          * parent) then the source directory must not be in the
 1075          * directory heirarchy above the target, as this would
 1076          * orphan everything below the source directory. Also
 1077          * the user must have write permission in the source so
 1078          * as to be able to change "..". We must repeat the call
 1079          * to namei, as the parent directory is unlocked by the
 1080          * call to doscheckpath().
 1081          */
 1082         error = VOP_ACCESS(fvp, VWRITE, tcnp->cn_cred, tcnp->cn_thread);
 1083         VOP_UNLOCK(fvp, 0);
 1084         if (VTODE(fdvp)->de_StartCluster != VTODE(tdvp)->de_StartCluster)
 1085                 newparent = 1;
 1086         if (doingdirectory && newparent) {
 1087                 if (error)      /* write access check above */
 1088                         goto bad;
 1089                 if (xp != NULL)
 1090                         vput(tvp);
 1091                 /*
 1092                  * doscheckpath() vput()'s dp,
 1093                  * so we have to do a relookup afterwards
 1094                  */
 1095                 error = doscheckpath(ip, dp);
 1096                 if (error)
 1097                         goto out;
 1098                 if ((tcnp->cn_flags & SAVESTART) == 0)
 1099                         panic("msdosfs_rename: lost to startdir");
 1100                 error = relookup(tdvp, &tvp, tcnp);
 1101                 if (error)
 1102                         goto out;
 1103                 dp = VTODE(tdvp);
 1104                 xp = tvp ? VTODE(tvp) : NULL;
 1105         }
 1106 
 1107         if (xp != NULL) {
 1108                 /*
 1109                  * Target must be empty if a directory and have no links
 1110                  * to it. Also, ensure source and target are compatible
 1111                  * (both directories, or both not directories).
 1112                  */
 1113                 if (xp->de_Attributes & ATTR_DIRECTORY) {
 1114                         if (!dosdirempty(xp)) {
 1115                                 error = ENOTEMPTY;
 1116                                 goto bad;
 1117                         }
 1118                         if (!doingdirectory) {
 1119                                 error = ENOTDIR;
 1120                                 goto bad;
 1121                         }
 1122                         cache_purge(tdvp);
 1123                 } else if (doingdirectory) {
 1124                         error = EISDIR;
 1125                         goto bad;
 1126                 }
 1127                 error = removede(dp, xp);
 1128                 if (error)
 1129                         goto bad;
 1130                 vput(tvp);
 1131                 xp = NULL;
 1132         }
 1133 
 1134         /*
 1135          * Convert the filename in tcnp into a dos filename. We copy this
 1136          * into the denode and directory entry for the destination
 1137          * file/directory.
 1138          */
 1139         error = uniqdosname(VTODE(tdvp), tcnp, toname);
 1140         if (error)
 1141                 goto abortit;
 1142 
 1143         /*
 1144          * Since from wasn't locked at various places above,
 1145          * have to do a relookup here.
 1146          */
 1147         fcnp->cn_flags &= ~MODMASK;
 1148         fcnp->cn_flags |= LOCKPARENT | LOCKLEAF;
 1149         if ((fcnp->cn_flags & SAVESTART) == 0)
 1150                 panic("msdosfs_rename: lost from startdir");
 1151         if (!newparent)
 1152                 VOP_UNLOCK(tdvp, 0);
 1153         if (relookup(fdvp, &fvp, fcnp) == 0)
 1154                 vrele(fdvp);
 1155         if (fvp == NULL) {
 1156                 /*
 1157                  * From name has disappeared.
 1158                  */
 1159                 if (doingdirectory)
 1160                         panic("rename: lost dir entry");
 1161                 if (newparent)
 1162                         VOP_UNLOCK(tdvp, 0);
 1163                 vrele(tdvp);
 1164                 vrele(ap->a_fvp);
 1165                 return 0;
 1166         }
 1167         xp = VTODE(fvp);
 1168         zp = VTODE(fdvp);
 1169         from_diroffset = zp->de_fndoffset;
 1170 
 1171         /*
 1172          * Ensure that the directory entry still exists and has not
 1173          * changed till now. If the source is a file the entry may
 1174          * have been unlinked or renamed. In either case there is
 1175          * no further work to be done. If the source is a directory
 1176          * then it cannot have been rmdir'ed or renamed; this is
 1177          * prohibited by the DE_RENAME flag.
 1178          */
 1179         if (xp != ip) {
 1180                 if (doingdirectory)
 1181                         panic("rename: lost dir entry");
 1182                 VOP_UNLOCK(fvp, 0);
 1183                 if (newparent)
 1184                         VOP_UNLOCK(fdvp, 0);
 1185                 vrele(ap->a_fvp);
 1186                 xp = NULL;
 1187         } else {
 1188                 vrele(fvp);
 1189                 xp = NULL;
 1190 
 1191                 /*
 1192                  * First write a new entry in the destination
 1193                  * directory and mark the entry in the source directory
 1194                  * as deleted.  Then move the denode to the correct hash
 1195                  * chain for its new location in the filesystem.  And, if
 1196                  * we moved a directory, then update its .. entry to point
 1197                  * to the new parent directory.
 1198                  */
 1199                 bcopy(ip->de_Name, oldname, 11);
 1200                 bcopy(toname, ip->de_Name, 11); /* update denode */
 1201                 dp->de_fndoffset = to_diroffset;
 1202                 dp->de_fndcnt = to_count;
 1203                 error = createde(ip, dp, (struct denode **)0, tcnp);
 1204                 if (error) {
 1205                         bcopy(oldname, ip->de_Name, 11);
 1206                         if (newparent)
 1207                                 VOP_UNLOCK(fdvp, 0);
 1208                         VOP_UNLOCK(fvp, 0);
 1209                         goto bad;
 1210                 }
 1211                 ip->de_refcnt++;
 1212                 zp->de_fndoffset = from_diroffset;
 1213                 error = removede(zp, ip);
 1214                 if (error) {
 1215                         /* XXX should downgrade to ro here, fs is corrupt */
 1216                         if (newparent)
 1217                                 VOP_UNLOCK(fdvp, 0);
 1218                         VOP_UNLOCK(fvp, 0);
 1219                         goto bad;
 1220                 }
 1221                 if (!doingdirectory) {
 1222                         error = pcbmap(dp, de_cluster(pmp, to_diroffset), 0,
 1223                                        &ip->de_dirclust, 0);
 1224                         if (error) {
 1225                                 /* XXX should downgrade to ro here, fs is corrupt */
 1226                                 if (newparent)
 1227                                         VOP_UNLOCK(fdvp, 0);
 1228                                 VOP_UNLOCK(fvp, 0);
 1229                                 goto bad;
 1230                         }
 1231                         if (ip->de_dirclust == MSDOSFSROOT)
 1232                                 ip->de_diroffset = to_diroffset;
 1233                         else
 1234                                 ip->de_diroffset = to_diroffset & pmp->pm_crbomask;
 1235                 }
 1236                 reinsert(ip);
 1237                 if (newparent)
 1238                         VOP_UNLOCK(fdvp, 0);
 1239         }
 1240 
 1241         /*
 1242          * If we moved a directory to a new parent directory, then we must
 1243          * fixup the ".." entry in the moved directory.
 1244          */
 1245         if (doingdirectory && newparent) {
 1246                 cn = ip->de_StartCluster;
 1247                 if (cn == MSDOSFSROOT) {
 1248                         /* this should never happen */
 1249                         panic("msdosfs_rename(): updating .. in root directory?");
 1250                 } else
 1251                         bn = cntobn(pmp, cn);
 1252                 error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster,
 1253                               NOCRED, &bp);
 1254                 if (error) {
 1255                         /* XXX should downgrade to ro here, fs is corrupt */
 1256                         brelse(bp);
 1257                         VOP_UNLOCK(fvp, 0);
 1258                         goto bad;
 1259                 }
 1260                 dotdotp = (struct direntry *)bp->b_data + 1;
 1261                 putushort(dotdotp->deStartCluster, dp->de_StartCluster);
 1262                 if (FAT32(pmp))
 1263                         putushort(dotdotp->deHighClust, dp->de_StartCluster >> 16);
 1264                 if (fvp->v_mount->mnt_flag & MNT_ASYNC)
 1265                         bdwrite(bp);
 1266                 else if ((error = bwrite(bp)) != 0) {
 1267                         /* XXX should downgrade to ro here, fs is corrupt */
 1268                         VOP_UNLOCK(fvp, 0);
 1269                         goto bad;
 1270                 }
 1271         }
 1272 
 1273         VOP_UNLOCK(fvp, 0);
 1274 bad:
 1275         if (xp)
 1276                 vput(tvp);
 1277         vput(tdvp);
 1278 out:
 1279         ip->de_flag &= ~DE_RENAME;
 1280         vrele(fdvp);
 1281         vrele(fvp);
 1282         return (error);
 1283 
 1284 }
 1285 
 1286 static struct {
 1287         struct direntry dot;
 1288         struct direntry dotdot;
 1289 } dosdirtemplate = {
 1290         {       ".       ", "   ",                      /* the . entry */
 1291                 ATTR_DIRECTORY,                         /* file attribute */
 1292                 0,                                      /* reserved */
 1293                 0, { 0, 0 }, { 0, 0 },                  /* create time & date */
 1294                 { 0, 0 },                               /* access date */
 1295                 { 0, 0 },                               /* high bits of start cluster */
 1296                 { 210, 4 }, { 210, 4 },                 /* modify time & date */
 1297                 { 0, 0 },                               /* startcluster */
 1298                 { 0, 0, 0, 0 }                          /* filesize */
 1299         },
 1300         {       "..      ", "   ",                      /* the .. entry */
 1301                 ATTR_DIRECTORY,                         /* file attribute */
 1302                 0,                                      /* reserved */
 1303                 0, { 0, 0 }, { 0, 0 },                  /* create time & date */
 1304                 { 0, 0 },                               /* access date */
 1305                 { 0, 0 },                               /* high bits of start cluster */
 1306                 { 210, 4 }, { 210, 4 },                 /* modify time & date */
 1307                 { 0, 0 },                               /* startcluster */
 1308                 { 0, 0, 0, 0 }                          /* filesize */
 1309         }
 1310 };
 1311 
 1312 static int
 1313 msdosfs_mkdir(ap)
 1314         struct vop_mkdir_args /* {
 1315                 struct vnode *a_dvp;
 1316                 struct vnode **a_vpp;
 1317                 struvt componentname *a_cnp;
 1318                 struct vattr *a_vap;
 1319         } */ *ap;
 1320 {
 1321         struct componentname *cnp = ap->a_cnp;
 1322         struct denode *dep;
 1323         struct denode *pdep = VTODE(ap->a_dvp);
 1324         struct direntry *denp;
 1325         struct msdosfsmount *pmp = pdep->de_pmp;
 1326         struct buf *bp;
 1327         u_long newcluster, pcl;
 1328         int bn;
 1329         int error;
 1330         struct denode ndirent;
 1331         struct timespec ts;
 1332 
 1333         /*
 1334          * If this is the root directory and there is no space left we
 1335          * can't do anything.  This is because the root directory can not
 1336          * change size.
 1337          */
 1338         if (pdep->de_StartCluster == MSDOSFSROOT
 1339             && pdep->de_fndoffset >= pdep->de_FileSize) {
 1340                 error = ENOSPC;
 1341                 goto bad2;
 1342         }
 1343 
 1344         /*
 1345          * Allocate a cluster to hold the about to be created directory.
 1346          */
 1347         error = clusteralloc(pmp, 0, 1, CLUST_EOFE, &newcluster, NULL);
 1348         if (error)
 1349                 goto bad2;
 1350 
 1351         bzero(&ndirent, sizeof(ndirent));
 1352         ndirent.de_pmp = pmp;
 1353         ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE;
 1354         getnanotime(&ts);
 1355         DETIMES(&ndirent, &ts, &ts, &ts);
 1356 
 1357         /*
 1358          * Now fill the cluster with the "." and ".." entries. And write
 1359          * the cluster to disk.  This way it is there for the parent
 1360          * directory to be pointing at if there were a crash.
 1361          */
 1362         bn = cntobn(pmp, newcluster);
 1363         /* always succeeds */
 1364         bp = getblk(pmp->pm_devvp, bn, pmp->pm_bpcluster, 0, 0, 0);
 1365         bzero(bp->b_data, pmp->pm_bpcluster);
 1366         bcopy(&dosdirtemplate, bp->b_data, sizeof dosdirtemplate);
 1367         denp = (struct direntry *)bp->b_data;
 1368         putushort(denp[0].deStartCluster, newcluster);
 1369         putushort(denp[0].deCDate, ndirent.de_CDate);
 1370         putushort(denp[0].deCTime, ndirent.de_CTime);
 1371         denp[0].deCHundredth = ndirent.de_CHun;
 1372         putushort(denp[0].deADate, ndirent.de_ADate);
 1373         putushort(denp[0].deMDate, ndirent.de_MDate);
 1374         putushort(denp[0].deMTime, ndirent.de_MTime);
 1375         pcl = pdep->de_StartCluster;
 1376         if (FAT32(pmp) && pcl == pmp->pm_rootdirblk)
 1377                 pcl = 0;
 1378         putushort(denp[1].deStartCluster, pcl);
 1379         putushort(denp[1].deCDate, ndirent.de_CDate);
 1380         putushort(denp[1].deCTime, ndirent.de_CTime);
 1381         denp[1].deCHundredth = ndirent.de_CHun;
 1382         putushort(denp[1].deADate, ndirent.de_ADate);
 1383         putushort(denp[1].deMDate, ndirent.de_MDate);
 1384         putushort(denp[1].deMTime, ndirent.de_MTime);
 1385         if (FAT32(pmp)) {
 1386                 putushort(denp[0].deHighClust, newcluster >> 16);
 1387                 putushort(denp[1].deHighClust, pdep->de_StartCluster >> 16);
 1388         }
 1389 
 1390         if (ap->a_dvp->v_mount->mnt_flag & MNT_ASYNC)
 1391                 bdwrite(bp);
 1392         else if ((error = bwrite(bp)) != 0)
 1393                 goto bad;
 1394 
 1395         /*
 1396          * Now build up a directory entry pointing to the newly allocated
 1397          * cluster.  This will be written to an empty slot in the parent
 1398          * directory.
 1399          */
 1400 #ifdef DIAGNOSTIC
 1401         if ((cnp->cn_flags & HASBUF) == 0)
 1402                 panic("msdosfs_mkdir: no name");
 1403 #endif
 1404         error = uniqdosname(pdep, cnp, ndirent.de_Name);
 1405         if (error)
 1406                 goto bad;
 1407 
 1408         ndirent.de_Attributes = ATTR_DIRECTORY;
 1409         ndirent.de_LowerCase = 0;
 1410         ndirent.de_StartCluster = newcluster;
 1411         ndirent.de_FileSize = 0;
 1412         error = createde(&ndirent, pdep, &dep, cnp);
 1413         if (error)
 1414                 goto bad;
 1415         *ap->a_vpp = DETOV(dep);
 1416         return (0);
 1417 
 1418 bad:
 1419         clusterfree(pmp, newcluster, NULL);
 1420 bad2:
 1421         return (error);
 1422 }
 1423 
 1424 static int
 1425 msdosfs_rmdir(ap)
 1426         struct vop_rmdir_args /* {
 1427                 struct vnode *a_dvp;
 1428                 struct vnode *a_vp;
 1429                 struct componentname *a_cnp;
 1430         } */ *ap;
 1431 {
 1432         struct vnode *vp = ap->a_vp;
 1433         struct vnode *dvp = ap->a_dvp;
 1434         struct componentname *cnp = ap->a_cnp;
 1435         struct denode *ip, *dp;
 1436         struct thread *td = cnp->cn_thread;
 1437         int error;
 1438 
 1439         ip = VTODE(vp);
 1440         dp = VTODE(dvp);
 1441 
 1442         /*
 1443          * Verify the directory is empty (and valid).
 1444          * (Rmdir ".." won't be valid since
 1445          *  ".." will contain a reference to
 1446          *  the current directory and thus be
 1447          *  non-empty.)
 1448          */
 1449         error = 0;
 1450         if (!dosdirempty(ip) || ip->de_flag & DE_RENAME) {
 1451                 error = ENOTEMPTY;
 1452                 goto out;
 1453         }
 1454         /*
 1455          * Delete the entry from the directory.  For dos filesystems this
 1456          * gets rid of the directory entry on disk, the in memory copy
 1457          * still exists but the de_refcnt is <= 0.  This prevents it from
 1458          * being found by deget().  When the vput() on dep is done we give
 1459          * up access and eventually msdosfs_reclaim() will be called which
 1460          * will remove it from the denode cache.
 1461          */
 1462         error = removede(dp, ip);
 1463         if (error)
 1464                 goto out;
 1465         /*
 1466          * This is where we decrement the link count in the parent
 1467          * directory.  Since dos filesystems don't do this we just purge
 1468          * the name cache.
 1469          */
 1470         cache_purge(dvp);
 1471         VOP_UNLOCK(dvp, 0);
 1472         /*
 1473          * Truncate the directory that is being deleted.
 1474          */
 1475         error = detrunc(ip, (u_long)0, IO_SYNC, cnp->cn_cred, td);
 1476         cache_purge(vp);
 1477 
 1478         vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
 1479 out:
 1480         return (error);
 1481 }
 1482 
 1483 /*
 1484  * DOS filesystems don't know what symlinks are.
 1485  */
 1486 static int
 1487 msdosfs_symlink(ap)
 1488         struct vop_symlink_args /* {
 1489                 struct vnode *a_dvp;
 1490                 struct vnode **a_vpp;
 1491                 struct componentname *a_cnp;
 1492                 struct vattr *a_vap;
 1493                 char *a_target;
 1494         } */ *ap;
 1495 {
 1496         return (EOPNOTSUPP);
 1497 }
 1498 
 1499 static int
 1500 msdosfs_readdir(ap)
 1501         struct vop_readdir_args /* {
 1502                 struct vnode *a_vp;
 1503                 struct uio *a_uio;
 1504                 struct ucred *a_cred;
 1505                 int *a_eofflag;
 1506                 int *a_ncookies;
 1507                 u_long **a_cookies;
 1508         } */ *ap;
 1509 {
 1510         struct mbnambuf nb;
 1511         int error = 0;
 1512         int diff;
 1513         long n;
 1514         int blsize;
 1515         long on;
 1516         u_long cn;
 1517         uint64_t fileno;
 1518         u_long dirsperblk;
 1519         long bias = 0;
 1520         daddr_t bn, lbn;
 1521         struct buf *bp;
 1522         struct denode *dep = VTODE(ap->a_vp);
 1523         struct msdosfsmount *pmp = dep->de_pmp;
 1524         struct direntry *dentp;
 1525         struct dirent dirbuf;
 1526         struct uio *uio = ap->a_uio;
 1527         u_long *cookies = NULL;
 1528         int ncookies = 0;
 1529         off_t offset, off;
 1530         int chksum = -1;
 1531 
 1532 #ifdef MSDOSFS_DEBUG
 1533         printf("msdosfs_readdir(): vp %p, uio %p, cred %p, eofflagp %p\n",
 1534             ap->a_vp, uio, ap->a_cred, ap->a_eofflag);
 1535 #endif
 1536 
 1537         /*
 1538          * msdosfs_readdir() won't operate properly on regular files since
 1539          * it does i/o only with the the filesystem vnode, and hence can
 1540          * retrieve the wrong block from the buffer cache for a plain file.
 1541          * So, fail attempts to readdir() on a plain file.
 1542          */
 1543         if ((dep->de_Attributes & ATTR_DIRECTORY) == 0)
 1544                 return (ENOTDIR);
 1545 
 1546         /*
 1547          * To be safe, initialize dirbuf
 1548          */
 1549         bzero(dirbuf.d_name, sizeof(dirbuf.d_name));
 1550 
 1551         /*
 1552          * If the user buffer is smaller than the size of one dos directory
 1553          * entry or the file offset is not a multiple of the size of a
 1554          * directory entry, then we fail the read.
 1555          */
 1556         off = offset = uio->uio_offset;
 1557         if (uio->uio_resid < sizeof(struct direntry) ||
 1558             (offset & (sizeof(struct direntry) - 1)))
 1559                 return (EINVAL);
 1560 
 1561         if (ap->a_ncookies) {
 1562                 ncookies = uio->uio_resid / 16;
 1563                 cookies = malloc(ncookies * sizeof(u_long), M_TEMP,
 1564                        M_WAITOK);
 1565                 *ap->a_cookies = cookies;
 1566                 *ap->a_ncookies = ncookies;
 1567         }
 1568 
 1569         dirsperblk = pmp->pm_BytesPerSec / sizeof(struct direntry);
 1570 
 1571         /*
 1572          * If they are reading from the root directory then, we simulate
 1573          * the . and .. entries since these don't exist in the root
 1574          * directory.  We also set the offset bias to make up for having to
 1575          * simulate these entries. By this I mean that at file offset 64 we
 1576          * read the first entry in the root directory that lives on disk.
 1577          */
 1578         if (dep->de_StartCluster == MSDOSFSROOT
 1579             || (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk)) {
 1580 #if 0
 1581                 printf("msdosfs_readdir(): going after . or .. in root dir, offset %d\n",
 1582                     offset);
 1583 #endif
 1584                 bias = 2 * sizeof(struct direntry);
 1585                 if (offset < bias) {
 1586                         for (n = (int)offset / sizeof(struct direntry);
 1587                              n < 2; n++) {
 1588                                 if (FAT32(pmp))
 1589                                         fileno = (uint64_t)cntobn(pmp,
 1590                                                                  pmp->pm_rootdirblk)
 1591                                                           * dirsperblk;
 1592                                 else
 1593                                         fileno = 1;
 1594                                 if (pmp->pm_flags & MSDOSFS_LARGEFS) {
 1595                                         dirbuf.d_fileno =
 1596                                             msdosfs_fileno_map(pmp->pm_mountp,
 1597                                             fileno);
 1598                                 } else {
 1599 
 1600                                         dirbuf.d_fileno = (uint32_t)fileno;
 1601                                 }
 1602                                 dirbuf.d_type = DT_DIR;
 1603                                 switch (n) {
 1604                                 case 0:
 1605                                         dirbuf.d_namlen = 1;
 1606                                         strcpy(dirbuf.d_name, ".");
 1607                                         break;
 1608                                 case 1:
 1609                                         dirbuf.d_namlen = 2;
 1610                                         strcpy(dirbuf.d_name, "..");
 1611                                         break;
 1612                                 }
 1613                                 dirbuf.d_reclen = GENERIC_DIRSIZ(&dirbuf);
 1614                                 if (uio->uio_resid < dirbuf.d_reclen)
 1615                                         goto out;
 1616                                 error = uiomove(&dirbuf, dirbuf.d_reclen, uio);
 1617                                 if (error)
 1618                                         goto out;
 1619                                 offset += sizeof(struct direntry);
 1620                                 off = offset;
 1621                                 if (cookies) {
 1622                                         *cookies++ = offset;
 1623                                         if (--ncookies <= 0)
 1624                                                 goto out;
 1625                                 }
 1626                         }
 1627                 }
 1628         }
 1629 
 1630         mbnambuf_init(&nb);
 1631         off = offset;
 1632         while (uio->uio_resid > 0) {
 1633                 lbn = de_cluster(pmp, offset - bias);
 1634                 on = (offset - bias) & pmp->pm_crbomask;
 1635                 n = min(pmp->pm_bpcluster - on, uio->uio_resid);
 1636                 diff = dep->de_FileSize - (offset - bias);
 1637                 if (diff <= 0)
 1638                         break;
 1639                 n = min(n, diff);
 1640                 error = pcbmap(dep, lbn, &bn, &cn, &blsize);
 1641                 if (error)
 1642                         break;
 1643                 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
 1644                 if (error) {
 1645                         brelse(bp);
 1646                         return (error);
 1647                 }
 1648                 n = min(n, blsize - bp->b_resid);
 1649                 if (n == 0) {
 1650                         brelse(bp);
 1651                         return (EIO);
 1652                 }
 1653 
 1654                 /*
 1655                  * Convert from dos directory entries to fs-independent
 1656                  * directory entries.
 1657                  */
 1658                 for (dentp = (struct direntry *)(bp->b_data + on);
 1659                      (char *)dentp < bp->b_data + on + n;
 1660                      dentp++, offset += sizeof(struct direntry)) {
 1661 #if 0
 1662                         printf("rd: dentp %08x prev %08x crnt %08x deName %02x attr %02x\n",
 1663                             dentp, prev, crnt, dentp->deName[0], dentp->deAttributes);
 1664 #endif
 1665                         /*
 1666                          * If this is an unused entry, we can stop.
 1667                          */
 1668                         if (dentp->deName[0] == SLOT_EMPTY) {
 1669                                 brelse(bp);
 1670                                 goto out;
 1671                         }
 1672                         /*
 1673                          * Skip deleted entries.
 1674                          */
 1675                         if (dentp->deName[0] == SLOT_DELETED) {
 1676                                 chksum = -1;
 1677                                 mbnambuf_init(&nb);
 1678                                 continue;
 1679                         }
 1680 
 1681                         /*
 1682                          * Handle Win95 long directory entries
 1683                          */
 1684                         if (dentp->deAttributes == ATTR_WIN95) {
 1685                                 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME)
 1686                                         continue;
 1687                                 chksum = win2unixfn(&nb,
 1688                                     (struct winentry *)dentp, chksum, pmp);
 1689                                 continue;
 1690                         }
 1691 
 1692                         /*
 1693                          * Skip volume labels
 1694                          */
 1695                         if (dentp->deAttributes & ATTR_VOLUME) {
 1696                                 chksum = -1;
 1697                                 mbnambuf_init(&nb);
 1698                                 continue;
 1699                         }
 1700                         /*
 1701                          * This computation of d_fileno must match
 1702                          * the computation of va_fileid in
 1703                          * msdosfs_getattr.
 1704                          */
 1705                         if (dentp->deAttributes & ATTR_DIRECTORY) {
 1706                                 fileno = getushort(dentp->deStartCluster);
 1707                                 if (FAT32(pmp))
 1708                                         fileno |= getushort(dentp->deHighClust) << 16;
 1709                                 /* if this is the root directory */
 1710                                 if (fileno == MSDOSFSROOT)
 1711                                         if (FAT32(pmp))
 1712                                                 fileno = (uint64_t)cntobn(pmp,
 1713                                                                 pmp->pm_rootdirblk)
 1714                                                          * dirsperblk;
 1715                                         else
 1716                                                 fileno = 1;
 1717                                 else
 1718                                         fileno = (uint64_t)cntobn(pmp, fileno) *
 1719                                             dirsperblk;
 1720                                 dirbuf.d_type = DT_DIR;
 1721                         } else {
 1722                                 fileno = (uoff_t)offset /
 1723                                     sizeof(struct direntry);
 1724                                 dirbuf.d_type = DT_REG;
 1725                         }
 1726                         if (pmp->pm_flags & MSDOSFS_LARGEFS) {
 1727                                 dirbuf.d_fileno =
 1728                                     msdosfs_fileno_map(pmp->pm_mountp, fileno);
 1729                         } else
 1730                                 dirbuf.d_fileno = (uint32_t)fileno;
 1731 
 1732                         if (chksum != winChksum(dentp)) {
 1733                                 dirbuf.d_namlen = dos2unixfn(dentp->deName,
 1734                                     (u_char *)dirbuf.d_name,
 1735                                     dentp->deLowerCase |
 1736                                         ((pmp->pm_flags & MSDOSFSMNT_SHORTNAME) ?
 1737                                         (LCASE_BASE | LCASE_EXT) : 0),
 1738                                     pmp);
 1739                                 mbnambuf_init(&nb);
 1740                         } else
 1741                                 mbnambuf_flush(&nb, &dirbuf);
 1742                         chksum = -1;
 1743                         dirbuf.d_reclen = GENERIC_DIRSIZ(&dirbuf);
 1744                         if (uio->uio_resid < dirbuf.d_reclen) {
 1745                                 brelse(bp);
 1746                                 goto out;
 1747                         }
 1748                         error = uiomove(&dirbuf, dirbuf.d_reclen, uio);
 1749                         if (error) {
 1750                                 brelse(bp);
 1751                                 goto out;
 1752                         }
 1753                         if (cookies) {
 1754                                 *cookies++ = offset + sizeof(struct direntry);
 1755                                 if (--ncookies <= 0) {
 1756                                         brelse(bp);
 1757                                         goto out;
 1758                                 }
 1759                         }
 1760                         off = offset + sizeof(struct direntry);
 1761                 }
 1762                 brelse(bp);
 1763         }
 1764 out:
 1765         /* Subtract unused cookies */
 1766         if (ap->a_ncookies)
 1767                 *ap->a_ncookies -= ncookies;
 1768 
 1769         uio->uio_offset = off;
 1770 
 1771         /*
 1772          * Set the eofflag (NFS uses it)
 1773          */
 1774         if (ap->a_eofflag) {
 1775                 if (dep->de_FileSize - (offset - bias) <= 0)
 1776                         *ap->a_eofflag = 1;
 1777                 else
 1778                         *ap->a_eofflag = 0;
 1779         }
 1780         return (error);
 1781 }
 1782 
 1783 /*-
 1784  * a_vp   - pointer to the file's vnode
 1785  * a_bn   - logical block number within the file (cluster number for us)
 1786  * a_bop  - where to return the bufobj of the special file containing the fs
 1787  * a_bnp  - where to return the "physical" block number corresponding to a_bn
 1788  *          (relative to the special file; units are blocks of size DEV_BSIZE)
 1789  * a_runp - where to return the "run past" a_bn.  This is the count of logical
 1790  *          blocks whose physical blocks (together with a_bn's physical block)
 1791  *          are contiguous.
 1792  * a_runb - where to return the "run before" a_bn.
 1793  */
 1794 static int
 1795 msdosfs_bmap(ap)
 1796         struct vop_bmap_args /* {
 1797                 struct vnode *a_vp;
 1798                 daddr_t a_bn;
 1799                 struct bufobj **a_bop;
 1800                 daddr_t *a_bnp;
 1801                 int *a_runp;
 1802                 int *a_runb;
 1803         } */ *ap;
 1804 {
 1805         struct denode *dep;
 1806         struct mount *mp;
 1807         struct msdosfsmount *pmp;
 1808         struct vnode *vp;
 1809         daddr_t runbn;
 1810         u_long cn;
 1811         int bnpercn, error, maxio, maxrun, run;
 1812 
 1813         vp = ap->a_vp;
 1814         dep = VTODE(vp);
 1815         pmp = dep->de_pmp;
 1816         if (ap->a_bop != NULL)
 1817                 *ap->a_bop = &pmp->pm_devvp->v_bufobj;
 1818         if (ap->a_bnp == NULL)
 1819                 return (0);
 1820         if (ap->a_runp != NULL)
 1821                 *ap->a_runp = 0;
 1822         if (ap->a_runb != NULL)
 1823                 *ap->a_runb = 0;
 1824         cn = ap->a_bn;
 1825         if (cn != ap->a_bn)
 1826                 return (EFBIG);
 1827         error = pcbmap(dep, cn, ap->a_bnp, NULL, NULL);
 1828         if (error != 0 || (ap->a_runp == NULL && ap->a_runb == NULL))
 1829                 return (error);
 1830 
 1831         mp = vp->v_mount;
 1832         maxio = mp->mnt_iosize_max / mp->mnt_stat.f_iosize;
 1833         bnpercn = de_cn2bn(pmp, 1);
 1834         if (ap->a_runp != NULL) {
 1835                 maxrun = ulmin(maxio - 1, pmp->pm_maxcluster - cn);
 1836                 for (run = 1; run <= maxrun; run++) {
 1837                         if (pcbmap(dep, cn + run, &runbn, NULL, NULL) != 0 ||
 1838                             runbn != *ap->a_bnp + run * bnpercn)
 1839                                 break;
 1840                 }
 1841                 *ap->a_runp = run - 1;
 1842         }
 1843         if (ap->a_runb != NULL) {
 1844                 maxrun = ulmin(maxio - 1, cn);
 1845                 for (run = 1; run < maxrun; run++) {
 1846                         if (pcbmap(dep, cn - run, &runbn, NULL, NULL) != 0 ||
 1847                             runbn != *ap->a_bnp - run * bnpercn)
 1848                                 break;
 1849                 }
 1850                 *ap->a_runb = run - 1;
 1851         }
 1852         return (0);
 1853 }
 1854 
 1855 static int
 1856 msdosfs_strategy(ap)
 1857         struct vop_strategy_args /* {
 1858                 struct vnode *a_vp;
 1859                 struct buf *a_bp;
 1860         } */ *ap;
 1861 {
 1862         struct buf *bp = ap->a_bp;
 1863         struct denode *dep = VTODE(ap->a_vp);
 1864         struct bufobj *bo;
 1865         int error = 0;
 1866         daddr_t blkno;
 1867 
 1868         /*
 1869          * If we don't already know the filesystem relative block number
 1870          * then get it using pcbmap().  If pcbmap() returns the block
 1871          * number as -1 then we've got a hole in the file.  DOS filesystems
 1872          * don't allow files with holes, so we shouldn't ever see this.
 1873          */
 1874         if (bp->b_blkno == bp->b_lblkno) {
 1875                 error = pcbmap(dep, bp->b_lblkno, &blkno, 0, 0);
 1876                 bp->b_blkno = blkno;
 1877                 if (error) {
 1878                         bp->b_error = error;
 1879                         bp->b_ioflags |= BIO_ERROR;
 1880                         bufdone(bp);
 1881                         return (0);
 1882                 }
 1883                 if ((long)bp->b_blkno == -1)
 1884                         vfs_bio_clrbuf(bp);
 1885         }
 1886         if (bp->b_blkno == -1) {
 1887                 bufdone(bp);
 1888                 return (0);
 1889         }
 1890         /*
 1891          * Read/write the block from/to the disk that contains the desired
 1892          * file block.
 1893          */
 1894         bp->b_iooffset = dbtob(bp->b_blkno);
 1895         bo = dep->de_pmp->pm_bo;
 1896         BO_STRATEGY(bo, bp);
 1897         return (0);
 1898 }
 1899 
 1900 static int
 1901 msdosfs_print(ap)
 1902         struct vop_print_args /* {
 1903                 struct vnode *vp;
 1904         } */ *ap;
 1905 {
 1906         struct denode *dep = VTODE(ap->a_vp);
 1907 
 1908         printf("\tstartcluster %lu, dircluster %lu, diroffset %lu, ",
 1909                dep->de_StartCluster, dep->de_dirclust, dep->de_diroffset);
 1910         printf("on dev %s\n", devtoname(dep->de_pmp->pm_dev));
 1911         return (0);
 1912 }
 1913 
 1914 static int
 1915 msdosfs_pathconf(ap)
 1916         struct vop_pathconf_args /* {
 1917                 struct vnode *a_vp;
 1918                 int a_name;
 1919                 int *a_retval;
 1920         } */ *ap;
 1921 {
 1922         struct msdosfsmount *pmp = VTODE(ap->a_vp)->de_pmp;
 1923 
 1924         switch (ap->a_name) {
 1925         case _PC_LINK_MAX:
 1926                 *ap->a_retval = 1;
 1927                 return (0);
 1928         case _PC_NAME_MAX:
 1929                 *ap->a_retval = pmp->pm_flags & MSDOSFSMNT_LONGNAME ? WIN_MAXLEN : 12;
 1930                 return (0);
 1931         case _PC_PATH_MAX:
 1932                 *ap->a_retval = PATH_MAX;
 1933                 return (0);
 1934         case _PC_CHOWN_RESTRICTED:
 1935                 *ap->a_retval = 1;
 1936                 return (0);
 1937         case _PC_NO_TRUNC:
 1938                 *ap->a_retval = 0;
 1939                 return (0);
 1940         default:
 1941                 return (EINVAL);
 1942         }
 1943         /* NOTREACHED */
 1944 }
 1945 
 1946 static int
 1947 msdosfs_vptofh(ap)
 1948         struct vop_vptofh_args /* {
 1949                 struct vnode *a_vp;
 1950                 struct fid *a_fhp;
 1951         } */ *ap;
 1952 {
 1953         struct denode *dep;
 1954         struct defid *defhp;
 1955 
 1956         dep = VTODE(ap->a_vp);
 1957         defhp = (struct defid *)ap->a_fhp;
 1958         defhp->defid_len = sizeof(struct defid);
 1959         defhp->defid_dirclust = dep->de_dirclust;
 1960         defhp->defid_dirofs = dep->de_diroffset;
 1961         /* defhp->defid_gen = dep->de_gen; */
 1962         return (0);
 1963 }
 1964 
 1965 /* Global vfs data structures for msdosfs */
 1966 struct vop_vector msdosfs_vnodeops = {
 1967         .vop_default =          &default_vnodeops,
 1968 
 1969         .vop_access =           msdosfs_access,
 1970         .vop_bmap =             msdosfs_bmap,
 1971         .vop_cachedlookup =     msdosfs_lookup,
 1972         .vop_open =             msdosfs_open,
 1973         .vop_close =            msdosfs_close,
 1974         .vop_create =           msdosfs_create,
 1975         .vop_fsync =            msdosfs_fsync,
 1976         .vop_getattr =          msdosfs_getattr,
 1977         .vop_inactive =         msdosfs_inactive,
 1978         .vop_link =             msdosfs_link,
 1979         .vop_lookup =           vfs_cache_lookup,
 1980         .vop_mkdir =            msdosfs_mkdir,
 1981         .vop_mknod =            msdosfs_mknod,
 1982         .vop_pathconf =         msdosfs_pathconf,
 1983         .vop_print =            msdosfs_print,
 1984         .vop_read =             msdosfs_read,
 1985         .vop_readdir =          msdosfs_readdir,
 1986         .vop_reclaim =          msdosfs_reclaim,
 1987         .vop_remove =           msdosfs_remove,
 1988         .vop_rename =           msdosfs_rename,
 1989         .vop_rmdir =            msdosfs_rmdir,
 1990         .vop_setattr =          msdosfs_setattr,
 1991         .vop_strategy =         msdosfs_strategy,
 1992         .vop_symlink =          msdosfs_symlink,
 1993         .vop_write =            msdosfs_write,
 1994         .vop_vptofh =           msdosfs_vptofh,
 1995 };

Cache object: fe4c879809e1305ba89079db46dd194e


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