2 * SPDX-License-Identifier: BSD-4-Clause
4 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
5 * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
7 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by TooLs GmbH.
20 * 4. The name of TooLs GmbH may not be used to endorse or promote products
21 * derived from this software without specific prior written permission.
23 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
27 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
28 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
29 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
30 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
31 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
32 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35 * Written by Paul Popelka (paulp@uts.amdahl.com)
37 * You can do anything you want with this software, just don't say you wrote
38 * it, and don't remove this notice.
40 * This software is provided "as is".
42 * The author supplies this software to be publicly redistributed on the
43 * understanding that the author is not responsible for the correct
44 * functioning of this software in any circumstances and is not liable for
45 * any damages caused by this software.
50 #include <sys/cdefs.h>
51 /* $NetBSD: msdosfs_vfsops.c,v 1.10 2016/01/30 09:59:27 mlelstv Exp $ */
52 __FBSDID("$FreeBSD$");
54 #include <sys/param.h>
55 #include <sys/mount.h>
65 #include <fs/msdosfs/bootsect.h>
66 #include <fs/msdosfs/bpb.h>
67 #include "msdos/direntry.h"
68 #include <fs/msdosfs/denode.h>
69 #include <fs/msdosfs/fat.h>
70 #include <fs/msdosfs/msdosfsmount.h>
72 #include <mkfs_msdos.h>
80 msdosfs_mount(struct vnode *devvp)
82 struct msdosfsmount *pmp = NULL;
84 union bootsector *bsp;
85 struct byte_bpb33 *b33;
86 struct byte_bpb50 *b50;
87 struct byte_bpb710 *b710;
91 unsigned secsize = 512;
93 MSDOSFS_DPRINTF(("%s(bread 0)\n", __func__));
94 if ((error = bread(devvp, 0, secsize, 0, &bp)) != 0)
97 bsp = (union bootsector *)bp->b_data;
98 b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
99 b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
100 b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
102 if (bsp->bs50.bsBootSectSig0 != BOOTSIG0 ||
103 bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
104 MSDOSFS_DPRINTF(("bootsig0 %d bootsig1 %d\n",
105 bsp->bs50.bsBootSectSig0,
106 bsp->bs50.bsBootSectSig1));
112 pmp = ecalloc(1, sizeof(*pmp));
114 * Compute several useful quantities from the bpb in the
115 * bootsector. Copy in the dos 5 variant of the bpb then fix up
116 * the fields that are different between dos 5 and dos 3.3.
118 SecPerClust = b50->bpbSecPerClust;
119 pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
120 pmp->pm_ResSectors = getushort(b50->bpbResSectors);
121 pmp->pm_FATs = b50->bpbFATs;
122 pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
123 pmp->pm_Sectors = getushort(b50->bpbSectors);
124 pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
125 pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
126 pmp->pm_Heads = getushort(b50->bpbHeads);
127 pmp->pm_Media = b50->bpbMedia;
129 MSDOSFS_DPRINTF(("%s(BytesPerSec=%u, ResSectors=%u, FATs=%d, "
130 "RootDirEnts=%u, Sectors=%u, FATsecs=%lu, SecPerTrack=%u, "
131 "Heads=%u, Media=%u)\n",
132 __func__, pmp->pm_BytesPerSec, pmp->pm_ResSectors,
133 pmp->pm_FATs, pmp->pm_RootDirEnts, pmp->pm_Sectors,
134 pmp->pm_FATsecs, pmp->pm_SecPerTrack, pmp->pm_Heads,
137 /* XXX - We should probably check more values here */
138 if (!pmp->pm_BytesPerSec || !SecPerClust
139 || pmp->pm_SecPerTrack > 63) {
140 MSDOSFS_DPRINTF(("bytespersec %d secperclust %d "
141 "secpertrack %d\n", pmp->pm_BytesPerSec,
142 SecPerClust, pmp->pm_SecPerTrack));
147 if (pmp->pm_Sectors == 0) {
148 pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
149 pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
151 pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
152 pmp->pm_HugeSectors = pmp->pm_Sectors;
156 if (pmp->pm_RootDirEnts == 0) {
157 unsigned short vers = getushort(b710->bpbFSVers);
159 * Some say that bsBootSectSig[23] must be zero, but
160 * Windows does not require this and some digital cameras
161 * do not set these to zero. Therefore, do not insist.
163 if (pmp->pm_Sectors || pmp->pm_FATsecs || vers) {
164 MSDOSFS_DPRINTF(("sectors %d fatsecs %lu vers %d\n",
165 pmp->pm_Sectors, pmp->pm_FATsecs, vers));
169 pmp->pm_fatmask = FAT32_MASK;
172 pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
174 /* mirrorring is enabled if the FATMIRROR bit is not set */
175 if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0)
176 pmp->pm_flags |= MSDOSFS_FATMIRROR;
178 pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
180 pmp->pm_flags |= MSDOSFS_FATMIRROR;
182 /* Check that fs has nonzero FAT size */
183 if (pmp->pm_FATsecs == 0) {
184 MSDOSFS_DPRINTF(("FATsecs is 0\n"));
189 pmp->pm_fatblk = pmp->pm_ResSectors;
191 pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
192 pmp->pm_firstcluster = pmp->pm_fatblk
193 + (pmp->pm_FATs * pmp->pm_FATsecs);
194 pmp->pm_fsinfo = getushort(b710->bpbFSInfo);
196 pmp->pm_rootdirblk = pmp->pm_fatblk +
197 (pmp->pm_FATs * pmp->pm_FATsecs);
198 pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
199 + pmp->pm_BytesPerSec - 1)
200 / pmp->pm_BytesPerSec;/* in sectors */
201 pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
204 pmp->pm_maxcluster = ((pmp->pm_HugeSectors - pmp->pm_firstcluster) /
206 pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec;
208 if (pmp->pm_fatmask == 0) {
209 if (pmp->pm_maxcluster
210 <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
212 * This will usually be a floppy disk. This size makes
213 * sure that one FAT entry will not be split across
216 pmp->pm_fatmask = FAT12_MASK;
220 pmp->pm_fatmask = FAT16_MASK;
226 pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
228 pmp->pm_fatblocksize = MAXBSIZE;
230 pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec;
231 pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1;
234 * Compute mask and shift value for isolating cluster relative byte
235 * offsets and cluster numbers from a file offset.
237 pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec;
238 pmp->pm_crbomask = pmp->pm_bpcluster - 1;
239 pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
241 MSDOSFS_DPRINTF(("%s(fatmask=%lu, fatmult=%u, fatdiv=%u, "
242 "fatblocksize=%lu, fatblocksec=%lu, bnshift=%lu, pbcluster=%lu, "
243 "crbomask=%lu, cnshift=%lu)\n",
244 __func__, (unsigned long)pmp->pm_fatmask, pmp->pm_fatmult,
245 pmp->pm_fatdiv, pmp->pm_fatblocksize, pmp->pm_fatblocksec,
246 pmp->pm_bnshift, pmp->pm_bpcluster, pmp->pm_crbomask,
249 * Check for valid cluster size
250 * must be a power of 2
252 if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
253 MSDOSFS_DPRINTF(("bpcluster %lu cnshift %lu\n",
254 pmp->pm_bpcluster, pmp->pm_cnshift));
260 * Release the bootsector buffer.
268 if (pmp->pm_fsinfo) {
272 * XXX If the fsinfo block is stored on media with
273 * 2KB or larger sectors, is the fsinfo structure
274 * padded at the end or in the middle?
276 if ((error = bread(devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
279 fp = (struct fsinfo *)bp->b_data;
280 if (!memcmp(fp->fsisig1, "RRaA", 4)
281 && !memcmp(fp->fsisig2, "rrAa", 4)
282 && !memcmp(fp->fsisig3, "\0\0\125\252", 4))
283 pmp->pm_nxtfree = getulong(fp->fsinxtfree);
291 * Check and validate (or perhaps invalidate?) the fsinfo structure?
294 if (pmp->pm_fsinfo) {
295 if ((pmp->pm_nxtfree == 0xffffffffUL) ||
296 (pmp->pm_nxtfree > pmp->pm_maxcluster))
301 * Allocate memory for the bitmap of allocated clusters, and then
304 pmp->pm_inusemap = ecalloc(sizeof(*pmp->pm_inusemap),
305 ((pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS));
307 * fillinusemap() needs pm_devvp.
310 pmp->pm_devvp = devvp;
313 * Have the inuse map filled in.
315 if ((error = fillinusemap(pmp)) != 0) {
316 MSDOSFS_DPRINTF(("fillinusemap %d\n", error));
324 pmp->pm_flags |= MSDOSFSMNT_RONLY;
329 * If we ever do quotas for DOS filesystems this would be a place
330 * to fill in the info in the msdosfsmount structure. You dolt,
331 * quotas on dos filesystems make no sense because files have no
332 * owners on dos filesystems. of course there is some empty space
333 * in the directory entry where we could put uid's and gid's.
342 if (pmp->pm_inusemap)
343 free(pmp->pm_inusemap);
351 msdosfs_root(struct msdosfsmount *pmp, struct vnode *vp) {
355 *vp = *pmp->pm_devvp;
356 if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep)) != 0) {
365 * If we have an FSInfo block, update it.
368 msdosfs_fsiflush(struct msdosfsmount *pmp)
374 if (pmp->pm_fsinfo == 0 || (pmp->pm_flags & MSDOSFS_FSIMOD) == 0) {
378 error = bread(pmp->pm_devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
384 fp = (struct fsinfo *)bp->b_data;
385 putulong(fp->fsinfree, pmp->pm_freeclustercount);
386 putulong(fp->fsinxtfree, pmp->pm_nxtfree);
387 pmp->pm_flags &= ~MSDOSFS_FSIMOD;