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  * 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/buf.h>
   54 #include <sys/conf.h>
   55 #include <sys/fcntl.h>
   56 #include <sys/iconv.h>
   57 #include <sys/kernel.h>
   58 #include <sys/lock.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/stat.h>
   66 #include <sys/vnode.h>
   67 
   68 #include <geom/geom.h>
   69 #include <geom/geom_vfs.h>
   70 
   71 #include <fs/msdosfs/bootsect.h>
   72 #include <fs/msdosfs/bpb.h>
   73 #include <fs/msdosfs/direntry.h>
   74 #include <fs/msdosfs/denode.h>
   75 #include <fs/msdosfs/fat.h>
   76 #include <fs/msdosfs/msdosfsmount.h>
   77 
   78 static const char msdosfs_lock_msg[] = "fatlk";
   79 
   80 /* Mount options that we support. */
   81 static const char *msdosfs_opts[] = {
   82         "async", "noatime", "noclusterr", "noclusterw",
   83         "export", "force", "from", "sync",
   84         "cs_dos", "cs_local", "cs_win", "dirmask",
   85         "gid", "kiconv", "large", "longname",
   86         "longnames", "mask", "shortname", "shortnames",
   87         "uid", "win95", "nowin95",
   88         NULL
   89 };
   90 
   91 #if 1 /*def PC98*/
   92 /*
   93  * XXX - The boot signature formatted by NEC PC-98 DOS looks like a
   94  *       garbage or a random value :-{
   95  *       If you want to use that broken-signatured media, define the
   96  *       following symbol even though PC/AT.
   97  *       (ex. mount PC-98 DOS formatted FD on PC/AT)
   98  */
   99 #define MSDOSFS_NOCHECKSIG
  100 #endif
  101 
  102 MALLOC_DEFINE(M_MSDOSFSMNT, "msdosfs_mount", "MSDOSFS mount structure");
  103 static MALLOC_DEFINE(M_MSDOSFSFAT, "msdosfs_fat", "MSDOSFS file allocation table");
  104 
  105 struct iconv_functions *msdosfs_iconv;
  106 
  107 static int      update_mp(struct mount *mp, struct thread *td);
  108 static int      mountmsdosfs(struct vnode *devvp, struct mount *mp);
  109 static vfs_fhtovp_t     msdosfs_fhtovp;
  110 static vfs_mount_t      msdosfs_mount;
  111 static vfs_root_t       msdosfs_root;
  112 static vfs_statfs_t     msdosfs_statfs;
  113 static vfs_sync_t       msdosfs_sync;
  114 static vfs_unmount_t    msdosfs_unmount;
  115 
  116 /* Maximum length of a character set name (arbitrary). */
  117 #define MAXCSLEN        64
  118 
  119 static int
  120 update_mp(struct mount *mp, struct thread *td)
  121 {
  122         struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
  123         void *dos, *win, *local;
  124         int error, v;
  125 
  126         if (!vfs_getopt(mp->mnt_optnew, "kiconv", NULL, NULL)) {
  127                 if (msdosfs_iconv != NULL) {
  128                         error = vfs_getopt(mp->mnt_optnew,
  129                             "cs_win", &win, NULL);
  130                         if (!error)
  131                                 error = vfs_getopt(mp->mnt_optnew,
  132                                     "cs_local", &local, NULL);
  133                         if (!error)
  134                                 error = vfs_getopt(mp->mnt_optnew,
  135                                     "cs_dos", &dos, NULL);
  136                         if (!error) {
  137                                 msdosfs_iconv->open(win, local, &pmp->pm_u2w);
  138                                 msdosfs_iconv->open(local, win, &pmp->pm_w2u);
  139                                 msdosfs_iconv->open(dos, local, &pmp->pm_u2d);
  140                                 msdosfs_iconv->open(local, dos, &pmp->pm_d2u);
  141                         }
  142                         if (error != 0)
  143                                 return (error);
  144                 } else {
  145                         pmp->pm_w2u = NULL;
  146                         pmp->pm_u2w = NULL;
  147                         pmp->pm_d2u = NULL;
  148                         pmp->pm_u2d = NULL;
  149                 }
  150         }
  151 
  152         if (vfs_scanopt(mp->mnt_optnew, "gid", "%d", &v) == 1)
  153                 pmp->pm_gid = v;
  154         if (vfs_scanopt(mp->mnt_optnew, "uid", "%d", &v) == 1)
  155                 pmp->pm_uid = v;
  156         if (vfs_scanopt(mp->mnt_optnew, "mask", "%d", &v) == 1)
  157                 pmp->pm_mask = v & ALLPERMS;
  158         if (vfs_scanopt(mp->mnt_optnew, "dirmask", "%d", &v) == 1)
  159                 pmp->pm_dirmask = v & ALLPERMS;
  160         vfs_flagopt(mp->mnt_optnew, "shortname",
  161             &pmp->pm_flags, MSDOSFSMNT_SHORTNAME);
  162         vfs_flagopt(mp->mnt_optnew, "shortnames",
  163             &pmp->pm_flags, MSDOSFSMNT_SHORTNAME);
  164         vfs_flagopt(mp->mnt_optnew, "longname",
  165             &pmp->pm_flags, MSDOSFSMNT_LONGNAME);
  166         vfs_flagopt(mp->mnt_optnew, "longnames",
  167             &pmp->pm_flags, MSDOSFSMNT_LONGNAME);
  168         vfs_flagopt(mp->mnt_optnew, "kiconv",
  169             &pmp->pm_flags, MSDOSFSMNT_KICONV);
  170 
  171         if (vfs_getopt(mp->mnt_optnew, "nowin95", NULL, NULL) == 0)
  172                 pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
  173         else
  174                 pmp->pm_flags &= ~MSDOSFSMNT_NOWIN95;
  175 
  176         if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
  177                 pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
  178         else if (!(pmp->pm_flags &
  179             (MSDOSFSMNT_SHORTNAME | MSDOSFSMNT_LONGNAME))) {
  180                 struct vnode *rootvp;
  181 
  182                 /*
  183                  * Try to divine whether to support Win'95 long filenames
  184                  */
  185                 if (FAT32(pmp))
  186                         pmp->pm_flags |= MSDOSFSMNT_LONGNAME;
  187                 else {
  188                         if ((error =
  189                             msdosfs_root(mp, LK_EXCLUSIVE, &rootvp)) != 0)
  190                                 return error;
  191                         pmp->pm_flags |= findwin95(VTODE(rootvp)) ?
  192                             MSDOSFSMNT_LONGNAME : MSDOSFSMNT_SHORTNAME;
  193                         vput(rootvp);
  194                 }
  195         }
  196         return 0;
  197 }
  198 
  199 static int
  200 msdosfs_cmount(struct mntarg *ma, void *data, uint64_t flags)
  201 {
  202         struct msdosfs_args args;
  203         struct export_args exp;
  204         int error;
  205 
  206         if (data == NULL)
  207                 return (EINVAL);
  208         error = copyin(data, &args, sizeof args);
  209         if (error)
  210                 return (error);
  211         vfs_oexport_conv(&args.export, &exp);
  212 
  213         ma = mount_argsu(ma, "from", args.fspec, MAXPATHLEN);
  214         ma = mount_arg(ma, "export", &exp, sizeof(exp));
  215         ma = mount_argf(ma, "uid", "%d", args.uid);
  216         ma = mount_argf(ma, "gid", "%d", args.gid);
  217         ma = mount_argf(ma, "mask", "%d", args.mask);
  218         ma = mount_argf(ma, "dirmask", "%d", args.dirmask);
  219 
  220         ma = mount_argb(ma, args.flags & MSDOSFSMNT_SHORTNAME, "noshortname");
  221         ma = mount_argb(ma, args.flags & MSDOSFSMNT_LONGNAME, "nolongname");
  222         ma = mount_argb(ma, !(args.flags & MSDOSFSMNT_NOWIN95), "nowin95");
  223         ma = mount_argb(ma, args.flags & MSDOSFSMNT_KICONV, "nokiconv");
  224 
  225         ma = mount_argsu(ma, "cs_win", args.cs_win, MAXCSLEN);
  226         ma = mount_argsu(ma, "cs_dos", args.cs_dos, MAXCSLEN);
  227         ma = mount_argsu(ma, "cs_local", args.cs_local, MAXCSLEN);
  228 
  229         error = kernel_mount(ma, flags);
  230 
  231         return (error);
  232 }
  233 
  234 /*
  235  * mp - path - addr in user space of mount point (ie /usr or whatever)
  236  * data - addr in user space of mount params including the name of the block
  237  * special file to treat as a filesystem.
  238  */
  239 static int
  240 msdosfs_mount(struct mount *mp)
  241 {
  242         struct vnode *devvp;      /* vnode for blk device to mount */
  243         struct thread *td;
  244         /* msdosfs specific mount control block */
  245         struct msdosfsmount *pmp = NULL;
  246         struct nameidata ndp;
  247         int error, flags;
  248         accmode_t accmode;
  249         char *from;
  250 
  251         td = curthread;
  252         if (vfs_filteropt(mp->mnt_optnew, msdosfs_opts))
  253                 return (EINVAL);
  254 
  255         /*
  256          * If updating, check whether changing from read-only to
  257          * read/write; if there is no device name, that's all we do.
  258          */
  259         if (mp->mnt_flag & MNT_UPDATE) {
  260                 pmp = VFSTOMSDOSFS(mp);
  261                 if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0)) {
  262                         /*
  263                          * Forbid export requests if filesystem has
  264                          * MSDOSFS_LARGEFS flag set.
  265                          */
  266                         if ((pmp->pm_flags & MSDOSFS_LARGEFS) != 0) {
  267                                 vfs_mount_error(mp,
  268                                     "MSDOSFS_LARGEFS flag set, cannot export");
  269                                 return (EOPNOTSUPP);
  270                         }
  271                 }
  272                 if (!(pmp->pm_flags & MSDOSFSMNT_RONLY) &&
  273                     vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0)) {
  274                         error = VFS_SYNC(mp, MNT_WAIT);
  275                         if (error)
  276                                 return (error);
  277                         flags = WRITECLOSE;
  278                         if (mp->mnt_flag & MNT_FORCE)
  279                                 flags |= FORCECLOSE;
  280                         error = vflush(mp, 0, flags, td);
  281                         if (error)
  282                                 return (error);
  283 
  284                         /*
  285                          * Now the volume is clean.  Mark it so while the
  286                          * device is still rw.
  287                          */
  288                         error = markvoldirty(pmp, 0);
  289                         if (error) {
  290                                 (void)markvoldirty(pmp, 1);
  291                                 return (error);
  292                         }
  293 
  294                         /* Downgrade the device from rw to ro. */
  295                         DROP_GIANT();
  296                         g_topology_lock();
  297                         error = g_access(pmp->pm_cp, 0, -1, 0);
  298                         g_topology_unlock();
  299                         PICKUP_GIANT();
  300                         if (error) {
  301                                 (void)markvoldirty(pmp, 1);
  302                                 return (error);
  303                         }
  304 
  305                         /*
  306                          * Backing out after an error was painful in the
  307                          * above.  Now we are committed to succeeding.
  308                          */
  309                         pmp->pm_fmod = 0;
  310                         pmp->pm_flags |= MSDOSFSMNT_RONLY;
  311                         MNT_ILOCK(mp);
  312                         mp->mnt_flag |= MNT_RDONLY;
  313                         MNT_IUNLOCK(mp);
  314                 } else if ((pmp->pm_flags & MSDOSFSMNT_RONLY) &&
  315                     !vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0)) {
  316                         /*
  317                          * If upgrade to read-write by non-root, then verify
  318                          * that user has necessary permissions on the device.
  319                          */
  320                         devvp = pmp->pm_devvp;
  321                         vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
  322                         error = VOP_ACCESS(devvp, VREAD | VWRITE,
  323                             td->td_ucred, td);
  324                         if (error)
  325                                 error = priv_check(td, PRIV_VFS_MOUNT_PERM);
  326                         if (error) {
  327                                 VOP_UNLOCK(devvp, 0);
  328                                 return (error);
  329                         }
  330                         VOP_UNLOCK(devvp, 0);
  331                         DROP_GIANT();
  332                         g_topology_lock();
  333                         error = g_access(pmp->pm_cp, 0, 1, 0);
  334                         g_topology_unlock();
  335                         PICKUP_GIANT();
  336                         if (error)
  337                                 return (error);
  338 
  339                         pmp->pm_fmod = 1;
  340                         pmp->pm_flags &= ~MSDOSFSMNT_RONLY;
  341                         MNT_ILOCK(mp);
  342                         mp->mnt_flag &= ~MNT_RDONLY;
  343                         MNT_IUNLOCK(mp);
  344 
  345                         /* Now that the volume is modifiable, mark it dirty. */
  346                         error = markvoldirty(pmp, 1);
  347                         if (error)
  348                                 return (error); 
  349                 }
  350         }
  351         /*
  352          * Not an update, or updating the name: look up the name
  353          * and verify that it refers to a sensible disk device.
  354          */
  355         if (vfs_getopt(mp->mnt_optnew, "from", (void **)&from, NULL))
  356                 return (EINVAL);
  357         NDINIT(&ndp, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, from, td);
  358         error = namei(&ndp);
  359         if (error)
  360                 return (error);
  361         devvp = ndp.ni_vp;
  362         NDFREE(&ndp, NDF_ONLY_PNBUF);
  363 
  364         if (!vn_isdisk(devvp, &error)) {
  365                 vput(devvp);
  366                 return (error);
  367         }
  368         /*
  369          * If mount by non-root, then verify that user has necessary
  370          * permissions on the device.
  371          */
  372         accmode = VREAD;
  373         if ((mp->mnt_flag & MNT_RDONLY) == 0)
  374                 accmode |= VWRITE;
  375         error = VOP_ACCESS(devvp, accmode, td->td_ucred, td);
  376         if (error)
  377                 error = priv_check(td, PRIV_VFS_MOUNT_PERM);
  378         if (error) {
  379                 vput(devvp);
  380                 return (error);
  381         }
  382         if ((mp->mnt_flag & MNT_UPDATE) == 0) {
  383                 error = mountmsdosfs(devvp, mp);
  384 #ifdef MSDOSFS_DEBUG            /* only needed for the printf below */
  385                 pmp = VFSTOMSDOSFS(mp);
  386 #endif
  387         } else {
  388                 vput(devvp);
  389                 if (devvp != pmp->pm_devvp)
  390                         return (EINVAL);        /* XXX needs translation */
  391         }
  392         if (error) {
  393                 vrele(devvp);
  394                 return (error);
  395         }
  396 
  397         error = update_mp(mp, td);
  398         if (error) {
  399                 if ((mp->mnt_flag & MNT_UPDATE) == 0)
  400                         msdosfs_unmount(mp, MNT_FORCE);
  401                 return error;
  402         }
  403 
  404         if (devvp->v_type == VCHR && devvp->v_rdev != NULL)
  405                 devvp->v_rdev->si_mountpt = mp;
  406         vfs_mountedfrom(mp, from);
  407 #ifdef MSDOSFS_DEBUG
  408         printf("msdosfs_mount(): mp %p, pmp %p, inusemap %p\n", mp, pmp, pmp->pm_inusemap);
  409 #endif
  410         return (0);
  411 }
  412 
  413 static int
  414 mountmsdosfs(struct vnode *devvp, struct mount *mp)
  415 {
  416         struct msdosfsmount *pmp;
  417         struct buf *bp;
  418         struct cdev *dev;
  419         union bootsector *bsp;
  420         struct byte_bpb33 *b33;
  421         struct byte_bpb50 *b50;
  422         struct byte_bpb710 *b710;
  423         u_int8_t SecPerClust;
  424         u_long clusters;
  425         int ronly, error;
  426         struct g_consumer *cp;
  427         struct bufobj *bo;
  428 
  429         bp = NULL;              /* This and pmp both used in error_exit. */
  430         pmp = NULL;
  431         ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
  432 
  433         dev = devvp->v_rdev;
  434         dev_ref(dev);
  435         DROP_GIANT();
  436         g_topology_lock();
  437         error = g_vfs_open(devvp, &cp, "msdosfs", ronly ? 0 : 1);
  438         g_topology_unlock();
  439         PICKUP_GIANT();
  440         VOP_UNLOCK(devvp, 0);
  441         if (error)
  442                 goto error_exit;
  443 
  444         bo = &devvp->v_bufobj;
  445 
  446         /*
  447          * Read the boot sector of the filesystem, and then check the
  448          * boot signature.  If not a dos boot sector then error out.
  449          *
  450          * NOTE: 8192 is a magic size that works for ffs.
  451          */
  452         error = bread(devvp, 0, 8192, NOCRED, &bp);
  453         if (error)
  454                 goto error_exit;
  455         bp->b_flags |= B_AGE;
  456         bsp = (union bootsector *)bp->b_data;
  457         b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
  458         b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
  459         b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
  460 
  461 #ifndef MSDOSFS_NOCHECKSIG
  462         if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
  463             || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
  464                 error = EINVAL;
  465                 goto error_exit;
  466         }
  467 #endif
  468 
  469         pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK | M_ZERO);
  470         pmp->pm_mountp = mp;
  471         pmp->pm_cp = cp;
  472         pmp->pm_bo = bo;
  473 
  474         lockinit(&pmp->pm_fatlock, 0, msdosfs_lock_msg, 0, 0);
  475 
  476         /*
  477          * Initialize ownerships and permissions, since nothing else will
  478          * initialize them iff we are mounting root.
  479          */
  480         pmp->pm_uid = UID_ROOT;
  481         pmp->pm_gid = GID_WHEEL;
  482         pmp->pm_mask = pmp->pm_dirmask = S_IXUSR | S_IXGRP | S_IXOTH |
  483             S_IRUSR | S_IRGRP | S_IROTH | S_IWUSR;
  484 
  485         /*
  486          * Experimental support for large MS-DOS filesystems.
  487          * WARNING: This uses at least 32 bytes of kernel memory (which is not
  488          * reclaimed until the FS is unmounted) for each file on disk to map
  489          * between the 32-bit inode numbers used by VFS and the 64-bit
  490          * pseudo-inode numbers used internally by msdosfs. This is only
  491          * safe to use in certain controlled situations (e.g. read-only FS
  492          * with less than 1 million files).
  493          * Since the mappings do not persist across unmounts (or reboots), these
  494          * filesystems are not suitable for exporting through NFS, or any other
  495          * application that requires fixed inode numbers.
  496          */
  497         vfs_flagopt(mp->mnt_optnew, "large", &pmp->pm_flags, MSDOSFS_LARGEFS);
  498 
  499         /*
  500          * Compute several useful quantities from the bpb in the
  501          * bootsector.  Copy in the dos 5 variant of the bpb then fix up
  502          * the fields that are different between dos 5 and dos 3.3.
  503          */
  504         SecPerClust = b50->bpbSecPerClust;
  505         pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
  506         if (pmp->pm_BytesPerSec < DEV_BSIZE) {
  507                 error = EINVAL;
  508                 goto error_exit;
  509         }
  510         pmp->pm_ResSectors = getushort(b50->bpbResSectors);
  511         pmp->pm_FATs = b50->bpbFATs;
  512         pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
  513         pmp->pm_Sectors = getushort(b50->bpbSectors);
  514         pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
  515         pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
  516         pmp->pm_Heads = getushort(b50->bpbHeads);
  517         pmp->pm_Media = b50->bpbMedia;
  518 
  519         /* calculate the ratio of sector size to DEV_BSIZE */
  520         pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;
  521 
  522         /*
  523          * We don't check pm_Heads nor pm_SecPerTrack, because
  524          * these may not be set for EFI file systems. We don't
  525          * use these anyway, so we're unaffected if they are
  526          * invalid.
  527          */
  528         if (!pmp->pm_BytesPerSec || !SecPerClust) {
  529                 error = EINVAL;
  530                 goto error_exit;
  531         }
  532 
  533         if (pmp->pm_Sectors == 0) {
  534                 pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
  535                 pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
  536         } else {
  537                 pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
  538                 pmp->pm_HugeSectors = pmp->pm_Sectors;
  539         }
  540         if (!(pmp->pm_flags & MSDOSFS_LARGEFS)) {
  541                 if (pmp->pm_HugeSectors > 0xffffffff /
  542                     (pmp->pm_BytesPerSec / sizeof(struct direntry)) + 1) {
  543                         /*
  544                          * We cannot deal currently with this size of disk
  545                          * due to fileid limitations (see msdosfs_getattr and
  546                          * msdosfs_readdir)
  547                          */
  548                         error = EINVAL;
  549                         vfs_mount_error(mp,
  550                             "Disk too big, try '-o large' mount option");
  551                         goto error_exit;
  552                 }
  553         }
  554 
  555         if (pmp->pm_RootDirEnts == 0) {
  556                 if (pmp->pm_FATsecs
  557                     || getushort(b710->bpbFSVers)) {
  558                         error = EINVAL;
  559 #ifdef MSDOSFS_DEBUG
  560                         printf("mountmsdosfs(): bad FAT32 filesystem\n");
  561 #endif
  562                         goto error_exit;
  563                 }
  564                 pmp->pm_fatmask = FAT32_MASK;
  565                 pmp->pm_fatmult = 4;
  566                 pmp->pm_fatdiv = 1;
  567                 pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
  568                 if (getushort(b710->bpbExtFlags) & FATMIRROR)
  569                         pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
  570                 else
  571                         pmp->pm_flags |= MSDOSFS_FATMIRROR;
  572         } else
  573                 pmp->pm_flags |= MSDOSFS_FATMIRROR;
  574 
  575         /*
  576          * Check a few values (could do some more):
  577          * - logical sector size: power of 2, >= block size
  578          * - sectors per cluster: power of 2, >= 1
  579          * - number of sectors:   >= 1, <= size of partition
  580          * - number of FAT sectors: >= 1
  581          */
  582         if ( (SecPerClust == 0)
  583           || (SecPerClust & (SecPerClust - 1))
  584           || (pmp->pm_BytesPerSec < DEV_BSIZE)
  585           || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
  586           || (pmp->pm_HugeSectors == 0)
  587           || (pmp->pm_FATsecs == 0)
  588           || (SecPerClust * pmp->pm_BlkPerSec > MAXBSIZE / DEV_BSIZE)
  589         ) {
  590                 error = EINVAL;
  591                 goto error_exit;
  592         }
  593 
  594         pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
  595         pmp->pm_HiddenSects *= pmp->pm_BlkPerSec;       /* XXX not used? */
  596         pmp->pm_FATsecs     *= pmp->pm_BlkPerSec;
  597         SecPerClust         *= pmp->pm_BlkPerSec;
  598 
  599         pmp->pm_fatblk = pmp->pm_ResSectors * pmp->pm_BlkPerSec;
  600 
  601         if (FAT32(pmp)) {
  602                 pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
  603                 pmp->pm_firstcluster = pmp->pm_fatblk
  604                         + (pmp->pm_FATs * pmp->pm_FATsecs);
  605                 pmp->pm_fsinfo = getushort(b710->bpbFSInfo) * pmp->pm_BlkPerSec;
  606         } else {
  607                 pmp->pm_rootdirblk = pmp->pm_fatblk +
  608                         (pmp->pm_FATs * pmp->pm_FATsecs);
  609                 pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
  610                                        + DEV_BSIZE - 1)
  611                         / DEV_BSIZE; /* in blocks */
  612                 pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
  613         }
  614 
  615         pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
  616             SecPerClust + 1;
  617         pmp->pm_fatsize = pmp->pm_FATsecs * DEV_BSIZE;  /* XXX not used? */
  618 
  619         if (pmp->pm_fatmask == 0) {
  620                 if (pmp->pm_maxcluster
  621                     <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
  622                         /*
  623                          * This will usually be a floppy disk. This size makes
  624                          * sure that one fat entry will not be split across
  625                          * multiple blocks.
  626                          */
  627                         pmp->pm_fatmask = FAT12_MASK;
  628                         pmp->pm_fatmult = 3;
  629                         pmp->pm_fatdiv = 2;
  630                 } else {
  631                         pmp->pm_fatmask = FAT16_MASK;
  632                         pmp->pm_fatmult = 2;
  633                         pmp->pm_fatdiv = 1;
  634                 }
  635         }
  636 
  637         clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
  638         if (pmp->pm_maxcluster >= clusters) {
  639 #ifdef MSDOSFS_DEBUG
  640                 printf("Warning: number of clusters (%ld) exceeds FAT "
  641                     "capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
  642 #endif
  643                 pmp->pm_maxcluster = clusters - 1;
  644         }
  645 
  646         if (FAT12(pmp))
  647                 pmp->pm_fatblocksize = 3 * 512;
  648         else
  649                 pmp->pm_fatblocksize = PAGE_SIZE;
  650         pmp->pm_fatblocksize = roundup(pmp->pm_fatblocksize,
  651             pmp->pm_BytesPerSec);
  652         pmp->pm_fatblocksec = pmp->pm_fatblocksize / DEV_BSIZE;
  653         pmp->pm_bnshift = ffs(DEV_BSIZE) - 1;
  654 
  655         /*
  656          * Compute mask and shift value for isolating cluster relative byte
  657          * offsets and cluster numbers from a file offset.
  658          */
  659         pmp->pm_bpcluster = SecPerClust * DEV_BSIZE;
  660         pmp->pm_crbomask = pmp->pm_bpcluster - 1;
  661         pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
  662 
  663         /*
  664          * Check for valid cluster size
  665          * must be a power of 2
  666          */
  667         if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
  668                 error = EINVAL;
  669                 goto error_exit;
  670         }
  671 
  672         /*
  673          * Release the bootsector buffer.
  674          */
  675         brelse(bp);
  676         bp = NULL;
  677 
  678         /*
  679          * Check the fsinfo sector if we have one.  Silently fix up our
  680          * in-core copy of fp->fsinxtfree if it is unknown (0xffffffff)
  681          * or too large.  Ignore fp->fsinfree for now, since we need to
  682          * read the entire FAT anyway to fill the inuse map.
  683          */
  684         if (pmp->pm_fsinfo) {
  685                 struct fsinfo *fp;
  686 
  687                 if ((error = bread(devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
  688                     NOCRED, &bp)) != 0)
  689                         goto error_exit;
  690                 fp = (struct fsinfo *)bp->b_data;
  691                 if (!bcmp(fp->fsisig1, "RRaA", 4)
  692                     && !bcmp(fp->fsisig2, "rrAa", 4)
  693                     && !bcmp(fp->fsisig3, "\0\0\125\252", 4)) {
  694                         pmp->pm_nxtfree = getulong(fp->fsinxtfree);
  695                         if (pmp->pm_nxtfree > pmp->pm_maxcluster)
  696                                 pmp->pm_nxtfree = CLUST_FIRST;
  697                 } else
  698                         pmp->pm_fsinfo = 0;
  699                 brelse(bp);
  700                 bp = NULL;
  701         }
  702 
  703         /*
  704          * Finish initializing pmp->pm_nxtfree (just in case the first few
  705          * sectors aren't properly reserved in the FAT).  This completes
  706          * the fixup for fp->fsinxtfree, and fixes up the zero-initialized
  707          * value if there is no fsinfo.  We will use pmp->pm_nxtfree
  708          * internally even if there is no fsinfo.
  709          */
  710         if (pmp->pm_nxtfree < CLUST_FIRST)
  711                 pmp->pm_nxtfree = CLUST_FIRST;
  712 
  713         /*
  714          * Allocate memory for the bitmap of allocated clusters, and then
  715          * fill it in.
  716          */
  717         pmp->pm_inusemap = malloc(howmany(pmp->pm_maxcluster + 1, N_INUSEBITS)
  718                                   * sizeof(*pmp->pm_inusemap),
  719                                   M_MSDOSFSFAT, M_WAITOK);
  720 
  721         /*
  722          * fillinusemap() needs pm_devvp.
  723          */
  724         pmp->pm_devvp = devvp;
  725         pmp->pm_dev = dev;
  726 
  727         /*
  728          * Have the inuse map filled in.
  729          */
  730         MSDOSFS_LOCK_MP(pmp);
  731         error = fillinusemap(pmp);
  732         MSDOSFS_UNLOCK_MP(pmp);
  733         if (error != 0)
  734                 goto error_exit;
  735 
  736         /*
  737          * If they want fat updates to be synchronous then let them suffer
  738          * the performance degradation in exchange for the on disk copy of
  739          * the fat being correct just about all the time.  I suppose this
  740          * would be a good thing to turn on if the kernel is still flakey.
  741          */
  742         if (mp->mnt_flag & MNT_SYNCHRONOUS)
  743                 pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
  744 
  745         /*
  746          * Finish up.
  747          */
  748         if (ronly)
  749                 pmp->pm_flags |= MSDOSFSMNT_RONLY;
  750         else {
  751                 if ((error = markvoldirty(pmp, 1)) != 0) {
  752                         (void)markvoldirty(pmp, 0);
  753                         goto error_exit;
  754                 }
  755                 pmp->pm_fmod = 1;
  756         }
  757         mp->mnt_data =  pmp;
  758         mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
  759         mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
  760         MNT_ILOCK(mp);
  761         mp->mnt_flag |= MNT_LOCAL;
  762         mp->mnt_kern_flag |= MNTK_MPSAFE;
  763         MNT_IUNLOCK(mp);
  764 
  765         if (pmp->pm_flags & MSDOSFS_LARGEFS)
  766                 msdosfs_fileno_init(mp);
  767 
  768         return 0;
  769 
  770 error_exit:
  771         if (bp)
  772                 brelse(bp);
  773         if (cp != NULL) {
  774                 DROP_GIANT();
  775                 g_topology_lock();
  776                 g_vfs_close(cp);
  777                 g_topology_unlock();
  778                 PICKUP_GIANT();
  779         }
  780         if (pmp) {
  781                 lockdestroy(&pmp->pm_fatlock);
  782                 if (pmp->pm_inusemap)
  783                         free(pmp->pm_inusemap, M_MSDOSFSFAT);
  784                 free(pmp, M_MSDOSFSMNT);
  785                 mp->mnt_data = NULL;
  786         }
  787         dev_rel(dev);
  788         return (error);
  789 }
  790 
  791 /*
  792  * Unmount the filesystem described by mp.
  793  */
  794 static int
  795 msdosfs_unmount(struct mount *mp, int mntflags)
  796 {
  797         struct msdosfsmount *pmp;
  798         int error, flags;
  799 
  800         flags = 0;
  801         if (mntflags & MNT_FORCE)
  802                 flags |= FORCECLOSE;
  803         error = vflush(mp, 0, flags, curthread);
  804         if (error && error != ENXIO)
  805                 return error;
  806         pmp = VFSTOMSDOSFS(mp);
  807         if ((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0) {
  808                 error = markvoldirty(pmp, 0);
  809                 if (error && error != ENXIO) {
  810                         (void)markvoldirty(pmp, 1);
  811                         return (error);
  812                 }
  813         }
  814         if (pmp->pm_flags & MSDOSFSMNT_KICONV && msdosfs_iconv) {
  815                 if (pmp->pm_w2u)
  816                         msdosfs_iconv->close(pmp->pm_w2u);
  817                 if (pmp->pm_u2w)
  818                         msdosfs_iconv->close(pmp->pm_u2w);
  819                 if (pmp->pm_d2u)
  820                         msdosfs_iconv->close(pmp->pm_d2u);
  821                 if (pmp->pm_u2d)
  822                         msdosfs_iconv->close(pmp->pm_u2d);
  823         }
  824 
  825 #ifdef MSDOSFS_DEBUG
  826         {
  827                 struct vnode *vp = pmp->pm_devvp;
  828                 struct bufobj *bo;
  829 
  830                 bo = &vp->v_bufobj;
  831                 BO_LOCK(bo);
  832                 VI_LOCK(vp);
  833                 vn_printf(vp,
  834                     "msdosfs_umount(): just before calling VOP_CLOSE()\n");
  835                 printf("freef %p, freeb %p, mount %p\n",
  836                     TAILQ_NEXT(vp, v_actfreelist), vp->v_actfreelist.tqe_prev,
  837                     vp->v_mount);
  838                 printf("cleanblkhd %p, dirtyblkhd %p, numoutput %ld, type %d\n",
  839                     TAILQ_FIRST(&vp->v_bufobj.bo_clean.bv_hd),
  840                     TAILQ_FIRST(&vp->v_bufobj.bo_dirty.bv_hd),
  841                     vp->v_bufobj.bo_numoutput, vp->v_type);
  842                 VI_UNLOCK(vp);
  843                 BO_UNLOCK(bo);
  844         }
  845 #endif
  846         DROP_GIANT();
  847         if (pmp->pm_devvp->v_type == VCHR && pmp->pm_devvp->v_rdev != NULL)
  848                 pmp->pm_devvp->v_rdev->si_mountpt = NULL;
  849         g_topology_lock();
  850         g_vfs_close(pmp->pm_cp);
  851         g_topology_unlock();
  852         PICKUP_GIANT();
  853         vrele(pmp->pm_devvp);
  854         dev_rel(pmp->pm_dev);
  855         free(pmp->pm_inusemap, M_MSDOSFSFAT);
  856         if (pmp->pm_flags & MSDOSFS_LARGEFS)
  857                 msdosfs_fileno_free(mp);
  858         lockdestroy(&pmp->pm_fatlock);
  859         free(pmp, M_MSDOSFSMNT);
  860         mp->mnt_data = NULL;
  861         MNT_ILOCK(mp);
  862         mp->mnt_flag &= ~MNT_LOCAL;
  863         MNT_IUNLOCK(mp);
  864         return (error);
  865 }
  866 
  867 static int
  868 msdosfs_root(struct mount *mp, int flags, struct vnode **vpp)
  869 {
  870         struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
  871         struct denode *ndep;
  872         int error;
  873 
  874 #ifdef MSDOSFS_DEBUG
  875         printf("msdosfs_root(); mp %p, pmp %p\n", mp, pmp);
  876 #endif
  877         error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep);
  878         if (error)
  879                 return (error);
  880         *vpp = DETOV(ndep);
  881         return (0);
  882 }
  883 
  884 static int
  885 msdosfs_statfs(struct mount *mp, struct statfs *sbp)
  886 {
  887         struct msdosfsmount *pmp;
  888 
  889         pmp = VFSTOMSDOSFS(mp);
  890         sbp->f_bsize = pmp->pm_bpcluster;
  891         sbp->f_iosize = pmp->pm_bpcluster;
  892         sbp->f_blocks = pmp->pm_maxcluster + 1;
  893         sbp->f_bfree = pmp->pm_freeclustercount;
  894         sbp->f_bavail = pmp->pm_freeclustercount;
  895         sbp->f_files = pmp->pm_RootDirEnts;     /* XXX */
  896         sbp->f_ffree = 0;       /* what to put in here? */
  897         return (0);
  898 }
  899 
  900 /*
  901  * If we have an FSInfo block, update it.
  902  */
  903 static int
  904 msdosfs_fsiflush(struct msdosfsmount *pmp, int waitfor)
  905 {
  906         struct fsinfo *fp;
  907         struct buf *bp;
  908         int error;
  909 
  910         MSDOSFS_LOCK_MP(pmp);
  911         if (pmp->pm_fsinfo == 0 || (pmp->pm_flags & MSDOSFS_FSIMOD) == 0) {
  912                 error = 0;
  913                 goto unlock;
  914         }
  915         error = bread(pmp->pm_devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
  916             NOCRED, &bp);
  917         if (error != 0) {
  918                 brelse(bp);
  919                 goto unlock;
  920         }
  921         fp = (struct fsinfo *)bp->b_data;
  922         putulong(fp->fsinfree, pmp->pm_freeclustercount);
  923         putulong(fp->fsinxtfree, pmp->pm_nxtfree);
  924         pmp->pm_flags &= ~MSDOSFS_FSIMOD;
  925         if (waitfor == MNT_WAIT)
  926                 error = bwrite(bp);
  927         else
  928                 bawrite(bp);
  929 unlock:
  930         MSDOSFS_UNLOCK_MP(pmp);
  931         return (error);
  932 }
  933 
  934 static int
  935 msdosfs_sync(struct mount *mp, int waitfor)
  936 {
  937         struct vnode *vp, *nvp;
  938         struct thread *td;
  939         struct denode *dep;
  940         struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
  941         int error, allerror = 0;
  942 
  943         td = curthread;
  944 
  945         /*
  946          * If we ever switch to not updating all of the fats all the time,
  947          * this would be the place to update them from the first one.
  948          */
  949         if (pmp->pm_fmod != 0) {
  950                 if (pmp->pm_flags & MSDOSFSMNT_RONLY)
  951                         panic("msdosfs_sync: rofs mod");
  952                 else {
  953                         /* update fats here */
  954                 }
  955         }
  956         /*
  957          * Write back each (modified) denode.
  958          */
  959 loop:
  960         MNT_VNODE_FOREACH_ALL(vp, mp, nvp) {
  961                 if (vp->v_type == VNON) {
  962                         VI_UNLOCK(vp);
  963                         continue;
  964                 }
  965                 dep = VTODE(vp);
  966                 if ((dep->de_flag &
  967                     (DE_ACCESS | DE_CREATE | DE_UPDATE | DE_MODIFIED)) == 0 &&
  968                     (vp->v_bufobj.bo_dirty.bv_cnt == 0 ||
  969                     waitfor == MNT_LAZY)) {
  970                         VI_UNLOCK(vp);
  971                         continue;
  972                 }
  973                 error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, td);
  974                 if (error) {
  975                         if (error == ENOENT)
  976                                 goto loop;
  977                         continue;
  978                 }
  979                 error = VOP_FSYNC(vp, waitfor, td);
  980                 if (error)
  981                         allerror = error;
  982                 VOP_UNLOCK(vp, 0);
  983                 vrele(vp);
  984         }
  985 
  986         /*
  987          * Flush filesystem control info.
  988          */
  989         if (waitfor != MNT_LAZY) {
  990                 vn_lock(pmp->pm_devvp, LK_EXCLUSIVE | LK_RETRY);
  991                 error = VOP_FSYNC(pmp->pm_devvp, waitfor, td);
  992                 if (error)
  993                         allerror = error;
  994                 VOP_UNLOCK(pmp->pm_devvp, 0);
  995         }
  996 
  997         error = msdosfs_fsiflush(pmp, waitfor);
  998         if (error != 0)
  999                 allerror = error;
 1000         return (allerror);
 1001 }
 1002 
 1003 static int
 1004 msdosfs_fhtovp(struct mount *mp, struct fid *fhp, int flags, struct vnode **vpp)
 1005 {
 1006         struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
 1007         struct defid *defhp = (struct defid *) fhp;
 1008         struct denode *dep;
 1009         int error;
 1010 
 1011         error = deget(pmp, defhp->defid_dirclust, defhp->defid_dirofs, &dep);
 1012         if (error) {
 1013                 *vpp = NULLVP;
 1014                 return (error);
 1015         }
 1016         *vpp = DETOV(dep);
 1017         vnode_create_vobject(*vpp, dep->de_FileSize, curthread);
 1018         return (0);
 1019 }
 1020 
 1021 static struct vfsops msdosfs_vfsops = {
 1022         .vfs_fhtovp =           msdosfs_fhtovp,
 1023         .vfs_mount =            msdosfs_mount,
 1024         .vfs_cmount =           msdosfs_cmount,
 1025         .vfs_root =             msdosfs_root,
 1026         .vfs_statfs =           msdosfs_statfs,
 1027         .vfs_sync =             msdosfs_sync,
 1028         .vfs_unmount =          msdosfs_unmount,
 1029 };
 1030 
 1031 VFS_SET(msdosfs_vfsops, msdosfs, 0);
 1032 MODULE_VERSION(msdosfs, 1);

Cache object: 10a61e173b5c3f623ec10da9e696ae5e


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