The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/fs/msdosfs/msdosfs_vfsops.c

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    1 /* $FreeBSD$ */
    2 /*      $NetBSD: msdosfs_vfsops.c,v 1.51 1997/11/17 15:36:58 ws Exp $   */
    3 
    4 /*-
    5  * SPDX-License-Identifier: BSD-4-Clause
    6  *
    7  * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
    8  * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
    9  * All rights reserved.
   10  * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
   11  *
   12  * Redistribution and use in source and binary forms, with or without
   13  * modification, are permitted provided that the following conditions
   14  * are met:
   15  * 1. Redistributions of source code must retain the above copyright
   16  *    notice, this list of conditions and the following disclaimer.
   17  * 2. Redistributions in binary form must reproduce the above copyright
   18  *    notice, this list of conditions and the following disclaimer in the
   19  *    documentation and/or other materials provided with the distribution.
   20  * 3. All advertising materials mentioning features or use of this software
   21  *    must display the following acknowledgement:
   22  *      This product includes software developed by TooLs GmbH.
   23  * 4. The name of TooLs GmbH may not be used to endorse or promote products
   24  *    derived from this software without specific prior written permission.
   25  *
   26  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
   27  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   28  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   29  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   31  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
   32  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
   33  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
   34  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
   35  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   36  */
   37 /*-
   38  * Written by Paul Popelka (paulp@uts.amdahl.com)
   39  *
   40  * You can do anything you want with this software, just don't say you wrote
   41  * it, and don't remove this notice.
   42  *
   43  * This software is provided "as is".
   44  *
   45  * The author supplies this software to be publicly redistributed on the
   46  * understanding that the author is not responsible for the correct
   47  * functioning of this software in any circumstances and is not liable for
   48  * any damages caused by this software.
   49  *
   50  * October 1992
   51  */
   52 
   53 #include <sys/param.h>
   54 #include <sys/systm.h>
   55 #include <sys/buf.h>
   56 #include <sys/conf.h>
   57 #include <sys/fcntl.h>
   58 #include <sys/iconv.h>
   59 #include <sys/kernel.h>
   60 #include <sys/lock.h>
   61 #include <sys/malloc.h>
   62 #include <sys/mount.h>
   63 #include <sys/mutex.h>
   64 #include <sys/namei.h>
   65 #include <sys/priv.h>
   66 #include <sys/proc.h>
   67 #include <sys/stat.h>
   68 #include <sys/vnode.h>
   69 
   70 #include <geom/geom.h>
   71 #include <geom/geom_vfs.h>
   72 
   73 #include <fs/msdosfs/bootsect.h>
   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 #ifdef MSDOSFS_DEBUG
   81 #include <sys/rwlock.h>
   82 #endif
   83 
   84 static const char msdosfs_lock_msg[] = "fatlk";
   85 
   86 /* Mount options that we support. */
   87 static const char *msdosfs_opts[] = {
   88         "async", "noatime", "noclusterr", "noclusterw",
   89         "export", "force", "from", "sync",
   90         "cs_dos", "cs_local", "cs_win", "dirmask",
   91         "gid", "kiconv", "longname",
   92         "longnames", "mask", "shortname", "shortnames",
   93         "uid", "win95", "nowin95",
   94         NULL
   95 };
   96 
   97 #if 1 /*def PC98*/
   98 /*
   99  * XXX - The boot signature formatted by NEC PC-98 DOS looks like a
  100  *       garbage or a random value :-{
  101  *       If you want to use that broken-signatured media, define the
  102  *       following symbol even though PC/AT.
  103  *       (ex. mount PC-98 DOS formatted FD on PC/AT)
  104  */
  105 #define MSDOSFS_NOCHECKSIG
  106 #endif
  107 
  108 MALLOC_DEFINE(M_MSDOSFSMNT, "msdosfs_mount", "MSDOSFS mount structure");
  109 static MALLOC_DEFINE(M_MSDOSFSFAT, "msdosfs_fat", "MSDOSFS file allocation table");
  110 
  111 struct iconv_functions *msdosfs_iconv;
  112 
  113 static int      update_mp(struct mount *mp, struct thread *td);
  114 static int      mountmsdosfs(struct vnode *devvp, struct mount *mp);
  115 static vfs_fhtovp_t     msdosfs_fhtovp;
  116 static vfs_mount_t      msdosfs_mount;
  117 static vfs_root_t       msdosfs_root;
  118 static vfs_statfs_t     msdosfs_statfs;
  119 static vfs_sync_t       msdosfs_sync;
  120 static vfs_unmount_t    msdosfs_unmount;
  121 
  122 /* Maximum length of a character set name (arbitrary). */
  123 #define MAXCSLEN        64
  124 
  125 static int
  126 update_mp(struct mount *mp, struct thread *td)
  127 {
  128         struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
  129         void *dos, *win, *local;
  130         int error, v;
  131 
  132         if (!vfs_getopt(mp->mnt_optnew, "kiconv", NULL, NULL)) {
  133                 if (msdosfs_iconv != NULL) {
  134                         error = vfs_getopt(mp->mnt_optnew,
  135                             "cs_win", &win, NULL);
  136                         if (!error)
  137                                 error = vfs_getopt(mp->mnt_optnew,
  138                                     "cs_local", &local, NULL);
  139                         if (!error)
  140                                 error = vfs_getopt(mp->mnt_optnew,
  141                                     "cs_dos", &dos, NULL);
  142                         if (!error) {
  143                                 msdosfs_iconv->open(win, local, &pmp->pm_u2w);
  144                                 msdosfs_iconv->open(local, win, &pmp->pm_w2u);
  145                                 msdosfs_iconv->open(dos, local, &pmp->pm_u2d);
  146                                 msdosfs_iconv->open(local, dos, &pmp->pm_d2u);
  147                         }
  148                         if (error != 0)
  149                                 return (error);
  150                 } else {
  151                         pmp->pm_w2u = NULL;
  152                         pmp->pm_u2w = NULL;
  153                         pmp->pm_d2u = NULL;
  154                         pmp->pm_u2d = NULL;
  155                 }
  156         }
  157 
  158         if (vfs_scanopt(mp->mnt_optnew, "gid", "%d", &v) == 1)
  159                 pmp->pm_gid = v;
  160         if (vfs_scanopt(mp->mnt_optnew, "uid", "%d", &v) == 1)
  161                 pmp->pm_uid = v;
  162         if (vfs_scanopt(mp->mnt_optnew, "mask", "%d", &v) == 1)
  163                 pmp->pm_mask = v & ALLPERMS;
  164         if (vfs_scanopt(mp->mnt_optnew, "dirmask", "%d", &v) == 1)
  165                 pmp->pm_dirmask = v & ALLPERMS;
  166         vfs_flagopt(mp->mnt_optnew, "shortname",
  167             &pmp->pm_flags, MSDOSFSMNT_SHORTNAME);
  168         vfs_flagopt(mp->mnt_optnew, "shortnames",
  169             &pmp->pm_flags, MSDOSFSMNT_SHORTNAME);
  170         vfs_flagopt(mp->mnt_optnew, "longname",
  171             &pmp->pm_flags, MSDOSFSMNT_LONGNAME);
  172         vfs_flagopt(mp->mnt_optnew, "longnames",
  173             &pmp->pm_flags, MSDOSFSMNT_LONGNAME);
  174         vfs_flagopt(mp->mnt_optnew, "kiconv",
  175             &pmp->pm_flags, MSDOSFSMNT_KICONV);
  176 
  177         if (vfs_getopt(mp->mnt_optnew, "nowin95", NULL, NULL) == 0)
  178                 pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
  179         else
  180                 pmp->pm_flags &= ~MSDOSFSMNT_NOWIN95;
  181 
  182         if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
  183                 pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
  184         else
  185                 pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
  186         return 0;
  187 }
  188 
  189 static int
  190 msdosfs_cmount(struct mntarg *ma, void *data, uint64_t flags)
  191 {
  192         struct msdosfs_args args;
  193         int error;
  194 
  195         if (data == NULL)
  196                 return (EINVAL);
  197         error = copyin(data, &args, sizeof args);
  198         if (error)
  199                 return (error);
  200 
  201         ma = mount_argsu(ma, "from", args.fspec, MAXPATHLEN);
  202         ma = mount_arg(ma, "export", &args.export, sizeof(args.export));
  203         ma = mount_argf(ma, "uid", "%d", args.uid);
  204         ma = mount_argf(ma, "gid", "%d", args.gid);
  205         ma = mount_argf(ma, "mask", "%d", args.mask);
  206         ma = mount_argf(ma, "dirmask", "%d", args.dirmask);
  207 
  208         ma = mount_argb(ma, args.flags & MSDOSFSMNT_SHORTNAME, "noshortname");
  209         ma = mount_argb(ma, args.flags & MSDOSFSMNT_LONGNAME, "nolongname");
  210         ma = mount_argb(ma, !(args.flags & MSDOSFSMNT_NOWIN95), "nowin95");
  211         ma = mount_argb(ma, args.flags & MSDOSFSMNT_KICONV, "nokiconv");
  212 
  213         ma = mount_argsu(ma, "cs_win", args.cs_win, MAXCSLEN);
  214         ma = mount_argsu(ma, "cs_dos", args.cs_dos, MAXCSLEN);
  215         ma = mount_argsu(ma, "cs_local", args.cs_local, MAXCSLEN);
  216 
  217         error = kernel_mount(ma, flags);
  218 
  219         return (error);
  220 }
  221 
  222 /*
  223  * mp - path - addr in user space of mount point (ie /usr or whatever)
  224  * data - addr in user space of mount params including the name of the block
  225  * special file to treat as a filesystem.
  226  */
  227 static int
  228 msdosfs_mount(struct mount *mp)
  229 {
  230         struct vnode *devvp;      /* vnode for blk device to mount */
  231         struct thread *td;
  232         /* msdosfs specific mount control block */
  233         struct msdosfsmount *pmp = NULL;
  234         struct nameidata ndp;
  235         int error, flags;
  236         accmode_t accmode;
  237         char *from;
  238 
  239         td = curthread;
  240         if (vfs_filteropt(mp->mnt_optnew, msdosfs_opts))
  241                 return (EINVAL);
  242 
  243         /*
  244          * If updating, check whether changing from read-only to
  245          * read/write; if there is no device name, that's all we do.
  246          */
  247         if (mp->mnt_flag & MNT_UPDATE) {
  248                 pmp = VFSTOMSDOSFS(mp);
  249                 if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) &&
  250                     vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0)) {
  251                         if ((error = vn_start_write(NULL, &mp, V_WAIT)) != 0)
  252                                 return (error);
  253                         error = vfs_write_suspend_umnt(mp);
  254                         if (error != 0)
  255                                 return (error);
  256 
  257                         flags = WRITECLOSE;
  258                         if (mp->mnt_flag & MNT_FORCE)
  259                                 flags |= FORCECLOSE;
  260                         error = vflush(mp, 0, flags, td);
  261                         if (error != 0) {
  262                                 vfs_write_resume(mp, 0);
  263                                 return (error);
  264                         }
  265 
  266                         /*
  267                          * Now the volume is clean.  Mark it so while the
  268                          * device is still rw.
  269                          */
  270                         error = markvoldirty(pmp, 0);
  271                         if (error != 0) {
  272                                 vfs_write_resume(mp, 0);
  273                                 (void)markvoldirty(pmp, 1);
  274                                 return (error);
  275                         }
  276 
  277                         /* Downgrade the device from rw to ro. */
  278                         g_topology_lock();
  279                         error = g_access(pmp->pm_cp, 0, -1, 0);
  280                         g_topology_unlock();
  281                         if (error) {
  282                                 vfs_write_resume(mp, 0);
  283                                 (void)markvoldirty(pmp, 1);
  284                                 return (error);
  285                         }
  286 
  287                         /*
  288                          * Backing out after an error was painful in the
  289                          * above.  Now we are committed to succeeding.
  290                          */
  291                         pmp->pm_fmod = 0;
  292                         pmp->pm_flags |= MSDOSFSMNT_RONLY;
  293                         MNT_ILOCK(mp);
  294                         mp->mnt_flag |= MNT_RDONLY;
  295                         MNT_IUNLOCK(mp);
  296                         vfs_write_resume(mp, 0);
  297                 } else if ((pmp->pm_flags & MSDOSFSMNT_RONLY) &&
  298                     !vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0)) {
  299                         /*
  300                          * If upgrade to read-write by non-root, then verify
  301                          * that user has necessary permissions on the device.
  302                          */
  303                         devvp = pmp->pm_devvp;
  304                         vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
  305                         error = VOP_ACCESS(devvp, VREAD | VWRITE,
  306                             td->td_ucred, td);
  307                         if (error)
  308                                 error = priv_check(td, PRIV_VFS_MOUNT_PERM);
  309                         if (error) {
  310                                 VOP_UNLOCK(devvp);
  311                                 return (error);
  312                         }
  313                         VOP_UNLOCK(devvp);
  314                         g_topology_lock();
  315                         error = g_access(pmp->pm_cp, 0, 1, 0);
  316                         g_topology_unlock();
  317                         if (error)
  318                                 return (error);
  319 
  320                         /* Now that the volume is modifiable, mark it dirty. */
  321                         error = markvoldirty_upgrade(pmp, true, true);
  322                         if (error) {
  323                                 /*
  324                                  * If dirtying the superblock failed, drop GEOM
  325                                  * 'w' refs (we're still RO).
  326                                  */
  327                                 g_topology_lock();
  328                                 (void)g_access(pmp->pm_cp, 0, -1, 0);
  329                                 g_topology_unlock();
  330 
  331                                 return (error);
  332                         }
  333 
  334                         pmp->pm_fmod = 1;
  335                         pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
  336                         MNT_ILOCK(mp);
  337                         mp->mnt_flag &= ~MNT_RDONLY;
  338                         MNT_IUNLOCK(mp);
  339                 }
  340         }
  341         /*
  342          * Not an update, or updating the name: look up the name
  343          * and verify that it refers to a sensible disk device.
  344          */
  345         if (vfs_getopt(mp->mnt_optnew, "from", (void **)&from, NULL))
  346                 return (EINVAL);
  347         NDINIT(&ndp, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, from, td);
  348         error = namei(&ndp);
  349         if (error)
  350                 return (error);
  351         devvp = ndp.ni_vp;
  352         NDFREE(&ndp, NDF_ONLY_PNBUF);
  353 
  354         if (!vn_isdisk_error(devvp, &error)) {
  355                 vput(devvp);
  356                 return (error);
  357         }
  358         /*
  359          * If mount by non-root, then verify that user has necessary
  360          * permissions on the device.
  361          */
  362         accmode = VREAD;
  363         if ((mp->mnt_flag & MNT_RDONLY) == 0)
  364                 accmode |= VWRITE;
  365         error = VOP_ACCESS(devvp, accmode, td->td_ucred, td);
  366         if (error)
  367                 error = priv_check(td, PRIV_VFS_MOUNT_PERM);
  368         if (error) {
  369                 vput(devvp);
  370                 return (error);
  371         }
  372         if ((mp->mnt_flag & MNT_UPDATE) == 0) {
  373                 error = mountmsdosfs(devvp, mp);
  374 #ifdef MSDOSFS_DEBUG            /* only needed for the printf below */
  375                 pmp = VFSTOMSDOSFS(mp);
  376 #endif
  377         } else {
  378                 vput(devvp);
  379                 if (devvp != pmp->pm_devvp)
  380                         return (EINVAL);        /* XXX needs translation */
  381         }
  382         if (error) {
  383                 vrele(devvp);
  384                 return (error);
  385         }
  386 
  387         error = update_mp(mp, td);
  388         if (error) {
  389                 if ((mp->mnt_flag & MNT_UPDATE) == 0)
  390                         msdosfs_unmount(mp, MNT_FORCE);
  391                 return error;
  392         }
  393 
  394         vfs_mountedfrom(mp, from);
  395 #ifdef MSDOSFS_DEBUG
  396         printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
  397 #endif
  398         return (0);
  399 }
  400 
  401 static int
  402 mountmsdosfs(struct vnode *devvp, struct mount *mp)
  403 {
  404         struct msdosfsmount *pmp;
  405         struct buf *bp;
  406         struct cdev *dev;
  407         union bootsector *bsp;
  408         struct byte_bpb33 *b33;
  409         struct byte_bpb50 *b50;
  410         struct byte_bpb710 *b710;
  411         uint8_t SecPerClust;
  412         u_long clusters;
  413         int ronly, error;
  414         struct g_consumer *cp;
  415         struct bufobj *bo;
  416 
  417         bp = NULL;              /* This and pmp both used in error_exit. */
  418         pmp = NULL;
  419         ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
  420 
  421         dev = devvp->v_rdev;
  422         if (atomic_cmpset_acq_ptr((uintptr_t *)&dev->si_mountpt, 0,
  423             (uintptr_t)mp) == 0) {
  424                 VOP_UNLOCK(devvp);
  425                 return (EBUSY);
  426         }
  427         g_topology_lock();
  428         error = g_vfs_open(devvp, &cp, "msdosfs", ronly ? 0 : 1);
  429         g_topology_unlock();
  430         if (error != 0) {
  431                 atomic_store_rel_ptr((uintptr_t *)&dev->si_mountpt, 0);
  432                 VOP_UNLOCK(devvp);
  433                 return (error);
  434         }
  435         dev_ref(dev);
  436         bo = &devvp->v_bufobj;
  437         VOP_UNLOCK(devvp);
  438         if (dev->si_iosize_max != 0)
  439                 mp->mnt_iosize_max = dev->si_iosize_max;
  440         if (mp->mnt_iosize_max > maxphys)
  441                 mp->mnt_iosize_max = maxphys;
  442 
  443         /*
  444          * Read the boot sector of the filesystem, and then check the
  445          * boot signature.  If not a dos boot sector then error out.
  446          *
  447          * NOTE: 8192 is a magic size that works for ffs.
  448          */
  449         error = bread(devvp, 0, 8192, NOCRED, &bp);
  450         if (error)
  451                 goto error_exit;
  452         bp->b_flags |= B_AGE;
  453         bsp = (union bootsector *)bp->b_data;
  454         b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
  455         b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
  456         b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
  457 
  458 #ifndef MSDOSFS_NOCHECKSIG
  459         if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
  460             || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
  461                 error = EINVAL;
  462                 goto error_exit;
  463         }
  464 #endif
  465 
  466         pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK | M_ZERO);
  467         pmp->pm_mountp = mp;
  468         pmp->pm_cp = cp;
  469         pmp->pm_bo = bo;
  470 
  471         lockinit(&pmp->pm_fatlock, 0, msdosfs_lock_msg, 0, 0);
  472 
  473         /*
  474          * Initialize ownerships and permissions, since nothing else will
  475          * initialize them iff we are mounting root.
  476          */
  477         pmp->pm_uid = UID_ROOT;
  478         pmp->pm_gid = GID_WHEEL;
  479         pmp->pm_mask = pmp->pm_dirmask = S_IXUSR | S_IXGRP | S_IXOTH |
  480             S_IRUSR | S_IRGRP | S_IROTH | S_IWUSR;
  481 
  482         /*
  483          * Compute several useful quantities from the bpb in the
  484          * bootsector.  Copy in the dos 5 variant of the bpb then fix up
  485          * the fields that are different between dos 5 and dos 3.3.
  486          */
  487         SecPerClust = b50->bpbSecPerClust;
  488         pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
  489         if (pmp->pm_BytesPerSec < DEV_BSIZE) {
  490                 error = EINVAL;
  491                 goto error_exit;
  492         }
  493         pmp->pm_ResSectors = getushort(b50->bpbResSectors);
  494         pmp->pm_FATs = b50->bpbFATs;
  495         pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
  496         pmp->pm_Sectors = getushort(b50->bpbSectors);
  497         pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
  498         pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
  499         pmp->pm_Heads = getushort(b50->bpbHeads);
  500         pmp->pm_Media = b50->bpbMedia;
  501 
  502         /* calculate the ratio of sector size to DEV_BSIZE */
  503         pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;
  504 
  505         /*
  506          * We don't check pm_Heads nor pm_SecPerTrack, because
  507          * these may not be set for EFI file systems. We don't
  508          * use these anyway, so we're unaffected if they are
  509          * invalid.
  510          */
  511         if (!pmp->pm_BytesPerSec || !SecPerClust) {
  512                 error = EINVAL;
  513                 goto error_exit;
  514         }
  515 
  516         if (pmp->pm_Sectors == 0) {
  517                 pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
  518                 pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
  519         } else {
  520                 pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
  521                 pmp->pm_HugeSectors = pmp->pm_Sectors;
  522         }
  523 
  524         if (pmp->pm_RootDirEnts == 0) {
  525                 if (pmp->pm_FATsecs
  526                     || getushort(b710->bpbFSVers)) {
  527                         error = EINVAL;
  528 #ifdef MSDOSFS_DEBUG
  529                         printf("mountmsdosfs(): bad FAT32 filesystem\n");
  530 #endif
  531                         goto error_exit;
  532                 }
  533                 pmp->pm_fatmask = FAT32_MASK;
  534                 pmp->pm_fatmult = 4;
  535                 pmp->pm_fatdiv = 1;
  536                 pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
  537                 if (getushort(b710->bpbExtFlags) & FATMIRROR)
  538                         pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
  539                 else
  540                         pmp->pm_flags |= MSDOSFS_FATMIRROR;
  541         } else
  542                 pmp->pm_flags |= MSDOSFS_FATMIRROR;
  543 
  544         /*
  545          * Check a few values (could do some more):
  546          * - logical sector size: power of 2, >= block size
  547          * - sectors per cluster: power of 2, >= 1
  548          * - number of sectors:   >= 1, <= size of partition
  549          * - number of FAT sectors: >= 1
  550          */
  551         if ( (SecPerClust == 0)
  552           || (SecPerClust & (SecPerClust - 1))
  553           || (pmp->pm_BytesPerSec < DEV_BSIZE)
  554           || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
  555           || (pmp->pm_HugeSectors == 0)
  556           || (pmp->pm_FATsecs == 0)
  557           || (SecPerClust * pmp->pm_BlkPerSec > MAXBSIZE / DEV_BSIZE)
  558         ) {
  559                 error = EINVAL;
  560                 goto error_exit;
  561         }
  562 
  563         pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
  564         pmp->pm_HiddenSects *= pmp->pm_BlkPerSec;       /* XXX not used? */
  565         pmp->pm_FATsecs     *= pmp->pm_BlkPerSec;
  566         SecPerClust         *= pmp->pm_BlkPerSec;
  567 
  568         pmp->pm_fatblk = pmp->pm_ResSectors * pmp->pm_BlkPerSec;
  569 
  570         if (FAT32(pmp)) {
  571                 pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
  572                 pmp->pm_firstcluster = pmp->pm_fatblk
  573                         + (pmp->pm_FATs * pmp->pm_FATsecs);
  574                 pmp->pm_fsinfo = getushort(b710->bpbFSInfo) * pmp->pm_BlkPerSec;
  575         } else {
  576                 pmp->pm_rootdirblk = pmp->pm_fatblk +
  577                         (pmp->pm_FATs * pmp->pm_FATsecs);
  578                 pmp->pm_rootdirsize = howmany(pmp->pm_RootDirEnts *
  579                         sizeof(struct direntry), DEV_BSIZE); /* in blocks */
  580                 pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
  581         }
  582 
  583         pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
  584             SecPerClust + 1;
  585         pmp->pm_fatsize = pmp->pm_FATsecs * DEV_BSIZE;  /* XXX not used? */
  586 
  587         if (pmp->pm_fatmask == 0) {
  588                 if (pmp->pm_maxcluster
  589                     <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
  590                         /*
  591                          * This will usually be a floppy disk. This size makes
  592                          * sure that one FAT entry will not be split across
  593                          * multiple blocks.
  594                          */
  595                         pmp->pm_fatmask = FAT12_MASK;
  596                         pmp->pm_fatmult = 3;
  597                         pmp->pm_fatdiv = 2;
  598                 } else {
  599                         pmp->pm_fatmask = FAT16_MASK;
  600                         pmp->pm_fatmult = 2;
  601                         pmp->pm_fatdiv = 1;
  602                 }
  603         }
  604 
  605         clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
  606         if (pmp->pm_maxcluster >= clusters) {
  607 #ifdef MSDOSFS_DEBUG
  608                 printf("Warning: number of clusters (%ld) exceeds FAT "
  609                     "capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
  610 #endif
  611                 pmp->pm_maxcluster = clusters - 1;
  612         }
  613 
  614         if (FAT12(pmp))
  615                 pmp->pm_fatblocksize = 3 * 512;
  616         else
  617                 pmp->pm_fatblocksize = PAGE_SIZE;
  618         pmp->pm_fatblocksize = roundup(pmp->pm_fatblocksize,
  619             pmp->pm_BytesPerSec);
  620         pmp->pm_fatblocksec = pmp->pm_fatblocksize / DEV_BSIZE;
  621         pmp->pm_bnshift = ffs(DEV_BSIZE) - 1;
  622 
  623         /*
  624          * Compute mask and shift value for isolating cluster relative byte
  625          * offsets and cluster numbers from a file offset.
  626          */
  627         pmp->pm_bpcluster = SecPerClust * DEV_BSIZE;
  628         pmp->pm_crbomask = pmp->pm_bpcluster - 1;
  629         pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
  630 
  631         /*
  632          * Check for valid cluster size
  633          * must be a power of 2
  634          */
  635         if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
  636                 error = EINVAL;
  637                 goto error_exit;
  638         }
  639 
  640         /*
  641          * Release the bootsector buffer.
  642          */
  643         brelse(bp);
  644         bp = NULL;
  645 
  646         /*
  647          * Check the fsinfo sector if we have one.  Silently fix up our
  648          * in-core copy of fp->fsinxtfree if it is unknown (0xffffffff)
  649          * or too large.  Ignore fp->fsinfree for now, since we need to
  650          * read the entire FAT anyway to fill the inuse map.
  651          */
  652         if (pmp->pm_fsinfo) {
  653                 struct fsinfo *fp;
  654 
  655                 if ((error = bread(devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
  656                     NOCRED, &bp)) != 0)
  657                         goto error_exit;
  658                 fp = (struct fsinfo *)bp->b_data;
  659                 if (!bcmp(fp->fsisig1, "RRaA", 4)
  660                     && !bcmp(fp->fsisig2, "rrAa", 4)
  661                     && !bcmp(fp->fsisig3, "\0\0\125\252", 4)) {
  662                         pmp->pm_nxtfree = getulong(fp->fsinxtfree);
  663                         if (pmp->pm_nxtfree > pmp->pm_maxcluster)
  664                                 pmp->pm_nxtfree = CLUST_FIRST;
  665                 } else
  666                         pmp->pm_fsinfo = 0;
  667                 brelse(bp);
  668                 bp = NULL;
  669         }
  670 
  671         /*
  672          * Finish initializing pmp->pm_nxtfree (just in case the first few
  673          * sectors aren't properly reserved in the FAT).  This completes
  674          * the fixup for fp->fsinxtfree, and fixes up the zero-initialized
  675          * value if there is no fsinfo.  We will use pmp->pm_nxtfree
  676          * internally even if there is no fsinfo.
  677          */
  678         if (pmp->pm_nxtfree < CLUST_FIRST)
  679                 pmp->pm_nxtfree = CLUST_FIRST;
  680 
  681         /*
  682          * Allocate memory for the bitmap of allocated clusters, and then
  683          * fill it in.
  684          */
  685         pmp->pm_inusemap = malloc(howmany(pmp->pm_maxcluster + 1, N_INUSEBITS)
  686                                   * sizeof(*pmp->pm_inusemap),
  687                                   M_MSDOSFSFAT, M_WAITOK);
  688 
  689         /*
  690          * fillinusemap() needs pm_devvp.
  691          */
  692         pmp->pm_devvp = devvp;
  693         pmp->pm_dev = dev;
  694 
  695         /*
  696          * Have the inuse map filled in.
  697          */
  698         MSDOSFS_LOCK_MP(pmp);
  699         error = fillinusemap(pmp);
  700         MSDOSFS_UNLOCK_MP(pmp);
  701         if (error != 0)
  702                 goto error_exit;
  703 
  704         /*
  705          * If they want FAT updates to be synchronous then let them suffer
  706          * the performance degradation in exchange for the on disk copy of
  707          * the FAT being correct just about all the time.  I suppose this
  708          * would be a good thing to turn on if the kernel is still flakey.
  709          */
  710         if (mp->mnt_flag & MNT_SYNCHRONOUS)
  711                 pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
  712 
  713         /*
  714          * Finish up.
  715          */
  716         if (ronly)
  717                 pmp->pm_flags |= MSDOSFSMNT_RONLY;
  718         else {
  719                 if ((error = markvoldirty(pmp, 1)) != 0)
  720                         goto error_exit;
  721                 pmp->pm_fmod = 1;
  722         }
  723         mp->mnt_data =  pmp;
  724         mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
  725         mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
  726         MNT_ILOCK(mp);
  727         mp->mnt_flag |= MNT_LOCAL;
  728         mp->mnt_kern_flag |= MNTK_USES_BCACHE | MNTK_NO_IOPF;
  729         MNT_IUNLOCK(mp);
  730 
  731         return (0);
  732 
  733 error_exit:
  734         if (bp)
  735                 brelse(bp);
  736         if (cp != NULL) {
  737                 g_topology_lock();
  738                 g_vfs_close(cp);
  739                 g_topology_unlock();
  740         }
  741         if (pmp) {
  742                 lockdestroy(&pmp->pm_fatlock);
  743                 free(pmp->pm_inusemap, M_MSDOSFSFAT);
  744                 free(pmp, M_MSDOSFSMNT);
  745                 mp->mnt_data = NULL;
  746         }
  747         atomic_store_rel_ptr((uintptr_t *)&dev->si_mountpt, 0);
  748         dev_rel(dev);
  749         return (error);
  750 }
  751 
  752 /*
  753  * Unmount the filesystem described by mp.
  754  */
  755 static int
  756 msdosfs_unmount(struct mount *mp, int mntflags)
  757 {
  758         struct msdosfsmount *pmp;
  759         int error, flags;
  760         bool susp;
  761 
  762         error = flags = 0;
  763         pmp = VFSTOMSDOSFS(mp);
  764         susp = (pmp->pm_flags & MSDOSFSMNT_RONLY) == 0;
  765 
  766         if (susp) {
  767                 error = vfs_write_suspend_umnt(mp);
  768                 if (error != 0)
  769                         return (error);
  770         }
  771 
  772         if ((mntflags & MNT_FORCE) != 0)
  773                 flags |= FORCECLOSE;
  774         error = vflush(mp, 0, flags, curthread);
  775         if (error != 0 && error != ENXIO) {
  776                 if (susp)
  777                         vfs_write_resume(mp, VR_START_WRITE);
  778                 return (error);
  779         }
  780         if (susp) {
  781                 error = markvoldirty(pmp, 0);
  782                 if (error != 0 && error != ENXIO) {
  783                         if (susp)
  784                                 vfs_write_resume(mp, VR_START_WRITE);
  785                         (void)markvoldirty(pmp, 1);
  786                         return (error);
  787                 }
  788         }
  789         if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
  790                 if (pmp->pm_w2u)
  791                         msdosfs_iconv->close(pmp->pm_w2u);
  792                 if (pmp->pm_u2w)
  793                         msdosfs_iconv->close(pmp->pm_u2w);
  794                 if (pmp->pm_d2u)
  795                         msdosfs_iconv->close(pmp->pm_d2u);
  796                 if (pmp->pm_u2d)
  797                         msdosfs_iconv->close(pmp->pm_u2d);
  798         }
  799 
  800 #ifdef MSDOSFS_DEBUG
  801         {
  802                 struct vnode *vp = pmp->pm_devvp;
  803                 struct bufobj *bo;
  804 
  805                 bo = &vp->v_bufobj;
  806                 BO_LOCK(bo);
  807                 VI_LOCK(vp);
  808                 vn_printf(vp,
  809                     "msdosfs_umount(): just before calling VOP_CLOSE()\n");
  810                 printf("freef %p, freeb %p, mount %p\n",
  811                     TAILQ_NEXT(vp, v_vnodelist), vp->v_vnodelist.tqe_prev,
  812                     vp->v_mount);
  813                 printf("cleanblkhd %p, dirtyblkhd %p, numoutput %d, type %d\n",
  814                     TAILQ_FIRST(&vp->v_bufobj.bo_clean.bv_hd),
  815                     TAILQ_FIRST(&vp->v_bufobj.bo_dirty.bv_hd),
  816                     vp->v_bufobj.bo_numoutput, vp->v_type);
  817                 VI_UNLOCK(vp);
  818                 BO_UNLOCK(bo);
  819         }
  820 #endif
  821         if (susp)
  822                 vfs_write_resume(mp, VR_START_WRITE);
  823 
  824         g_topology_lock();
  825         g_vfs_close(pmp->pm_cp);
  826         g_topology_unlock();
  827         atomic_store_rel_ptr((uintptr_t *)&pmp->pm_dev->si_mountpt, 0);
  828         vrele(pmp->pm_devvp);
  829         dev_rel(pmp->pm_dev);
  830         free(pmp->pm_inusemap, M_MSDOSFSFAT);
  831         lockdestroy(&pmp->pm_fatlock);
  832         free(pmp, M_MSDOSFSMNT);
  833         mp->mnt_data = NULL;
  834         MNT_ILOCK(mp);
  835         mp->mnt_flag &= ~MNT_LOCAL;
  836         MNT_IUNLOCK(mp);
  837         return (error);
  838 }
  839 
  840 static int
  841 msdosfs_root(struct mount *mp, int flags, struct vnode **vpp)
  842 {
  843         struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
  844         struct denode *ndep;
  845         int error;
  846 
  847 #ifdef MSDOSFS_DEBUG
  848         printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
  849 #endif
  850         error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep);
  851         if (error)
  852                 return (error);
  853         *vpp = DETOV(ndep);
  854         return (0);
  855 }
  856 
  857 static int
  858 msdosfs_statfs(struct mount *mp, struct statfs *sbp)
  859 {
  860         struct msdosfsmount *pmp;
  861 
  862         pmp = VFSTOMSDOSFS(mp);
  863         sbp->f_bsize = pmp->pm_bpcluster;
  864         sbp->f_iosize = pmp->pm_bpcluster;
  865         sbp->f_blocks = pmp->pm_maxcluster + 1;
  866         sbp->f_bfree = pmp->pm_freeclustercount;
  867         sbp->f_bavail = pmp->pm_freeclustercount;
  868         sbp->f_files = pmp->pm_RootDirEnts;     /* XXX */
  869         sbp->f_ffree = 0;       /* what to put in here? */
  870         return (0);
  871 }
  872 
  873 /*
  874  * If we have an FSInfo block, update it.
  875  */
  876 static int
  877 msdosfs_fsiflush(struct msdosfsmount *pmp, int waitfor)
  878 {
  879         struct fsinfo *fp;
  880         struct buf *bp;
  881         int error;
  882 
  883         MSDOSFS_LOCK_MP(pmp);
  884         if (pmp->pm_fsinfo == 0 || (pmp->pm_flags & MSDOSFS_FSIMOD) == 0) {
  885                 error = 0;
  886                 goto unlock;
  887         }
  888         error = bread(pmp->pm_devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
  889             NOCRED, &bp);
  890         if (error != 0) {
  891                 goto unlock;
  892         }
  893         fp = (struct fsinfo *)bp->b_data;
  894         putulong(fp->fsinfree, pmp->pm_freeclustercount);
  895         putulong(fp->fsinxtfree, pmp->pm_nxtfree);
  896         pmp->pm_flags &= ~MSDOSFS_FSIMOD;
  897         if (waitfor == MNT_WAIT)
  898                 error = bwrite(bp);
  899         else
  900                 bawrite(bp);
  901 unlock:
  902         MSDOSFS_UNLOCK_MP(pmp);
  903         return (error);
  904 }
  905 
  906 static int
  907 msdosfs_sync(struct mount *mp, int waitfor)
  908 {
  909         struct vnode *vp, *nvp;
  910         struct thread *td;
  911         struct denode *dep;
  912         struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
  913         int error, allerror = 0;
  914 
  915         td = curthread;
  916 
  917         /*
  918          * If we ever switch to not updating all of the FATs all the time,
  919          * this would be the place to update them from the first one.
  920          */
  921         if (pmp->pm_fmod != 0) {
  922                 if (pmp->pm_flags & MSDOSFSMNT_RONLY)
  923                         panic("msdosfs_sync: rofs mod");
  924                 else {
  925                         /* update FATs here */
  926                 }
  927         }
  928         /*
  929          * Write back each (modified) denode.
  930          */
  931 loop:
  932         MNT_VNODE_FOREACH_ALL(vp, mp, nvp) {
  933                 if (vp->v_type == VNON) {
  934                         VI_UNLOCK(vp);
  935                         continue;
  936                 }
  937                 dep = VTODE(vp);
  938                 if ((dep->de_flag &
  939                     (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0 &&
  940                     (vp->v_bufobj.bo_dirty.bv_cnt == 0 ||
  941                     waitfor == MNT_LAZY)) {
  942                         VI_UNLOCK(vp);
  943                         continue;
  944                 }
  945                 error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK);
  946                 if (error) {
  947                         if (error == ENOENT) {
  948                                 MNT_VNODE_FOREACH_ALL_ABORT(mp, nvp);
  949                                 goto loop;
  950                         }
  951                         continue;
  952                 }
  953                 error = VOP_FSYNC(vp, waitfor, td);
  954                 if (error)
  955                         allerror = error;
  956                 VOP_UNLOCK(vp);
  957                 vrele(vp);
  958         }
  959 
  960         /*
  961          * Flush filesystem control info.
  962          */
  963         if (waitfor != MNT_LAZY) {
  964                 vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY);
  965                 error = VOP_FSYNC(pmp->pm_devvp, waitfor, td);
  966                 if (error)
  967                         allerror = error;
  968                 VOP_UNLOCK(pmp->pm_devvp);
  969         }
  970 
  971         error = msdosfs_fsiflush(pmp, waitfor);
  972         if (error != 0)
  973                 allerror = error;
  974 
  975         if (allerror == 0 && waitfor == MNT_SUSPEND) {
  976                 MNT_ILOCK(mp);
  977                 mp->mnt_kern_flag |= MNTK_SUSPEND2 | MNTK_SUSPENDED;
  978                 MNT_IUNLOCK(mp);
  979         }
  980         return (allerror);
  981 }
  982 
  983 static int
  984 msdosfs_fhtovp(struct mount *mp, struct fid *fhp, int flags, struct vnode **vpp)
  985 {
  986         struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
  987         struct defid *defhp = (struct defid *) fhp;
  988         struct denode *dep;
  989         int error;
  990 
  991         error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
  992         if (error) {
  993                 *vpp = NULLVP;
  994                 return (error);
  995         }
  996         *vpp = DETOV(dep);
  997         vnode_create_vobject(*vpp, dep->de_FileSize, curthread);
  998         return (0);
  999 }
 1000 
 1001 static struct vfsops msdosfs_vfsops = {
 1002         .vfs_fhtovp =           msdosfs_fhtovp,
 1003         .vfs_mount =            msdosfs_mount,
 1004         .vfs_cmount =           msdosfs_cmount,
 1005         .vfs_root =             msdosfs_root,
 1006         .vfs_statfs =           msdosfs_statfs,
 1007         .vfs_sync =             msdosfs_sync,
 1008         .vfs_unmount =          msdosfs_unmount,
 1009 };
 1010 
 1011 VFS_SET(msdosfs_vfsops, msdosfs, 0);
 1012 MODULE_VERSION(msdosfs, 1);

Cache object: 242967fd7cd6a11324daaf66837b1c2d


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