fs/msdosfs/msdosfs_fat.c

67 static int	chainalloc(struct msdosfsmount *pmp, u_long start,
70 static int	chainlength(struct msdosfsmount *pmp, u_long start,
72 static void	fatblock(struct msdosfsmount *pmp, u_long ofs, u_long *bnp,
74 static int	fatchain(struct msdosfsmount *pmp, u_long start, u_long count,
78 static void	updatefats(struct msdosfsmount *pmp, struct buf *bp,
81 		usemap_alloc(struct msdosfsmount *pmp, u_long cn);
82 static int	usemap_free(struct msdosfsmount *pmp, u_long cn);
83 static int	clusteralloc1(struct msdosfsmount *pmp, u_long start,
88 fatblock(struct msdosfsmount *pmp, u_long ofs, u_long *bnp, u_long *sizep,
93 	fatblocksec = pmp->pm_fatblocksec;
94 	if (FAT12(pmp) && fatblocksec % 3 != 0) {
99 	bn = ofs / pmp->pm_fatblocksize * pmp->pm_fatblocksec;
100 	size = roundup(ulmin(fatblocksec, pmp->pm_FATsecs - bn) * DEV_BSIZE,
101 	    pmp->pm_BlkPerSec * DEV_BSIZE);
102 	bn += pmp->pm_fatblk + pmp->pm_curfat * pmp->pm_FATsecs;
109 		*bop = ofs % pmp->pm_fatblocksize;
143 	struct msdosfsmount *pmp = dep->de_pmp;
159 			if (de_cn2off(pmp, findcn) >= dep->de_FileSize) {
161 					*cnp = de_bn2cn(pmp, pmp->pm_rootdirsize);
165 				*bnp = pmp->pm_rootdirblk + de_cn2bn(pmp, findcn);
169 				*sp = min(pmp->pm_bpcluster,
170 				    dep->de_FileSize - de_cn2off(pmp, findcn));
183 		*sp = pmp->pm_bpcluster;
200 		if ((cn | ~pmp->pm_fatmask) >= CLUST_RSRVD)
202 		byteoffset = FATOFS(pmp, cn);
203 		fatblock(pmp, byteoffset, &bn, &bsize, &bo);
207 			error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
219 		if (FAT32(pmp))
223 		if (FAT12(pmp) && (prevcn & 1))
225 		cn &= pmp->pm_fatmask;
233 		if ((cn | ~pmp->pm_fatmask) >= CLUST_RSRVD)
234 			cn |= ~pmp->pm_fatmask;
237 	if (!MSDOSFSEOF(pmp, cn)) {
241 			*bnp = cntobn(pmp, cn);
308  * pmp	 - msdosfsmount structure for filesystem to update
313 updatefats(struct msdosfsmount *pmp, struct buf *bp, u_long fatbn)
319 	printf("updatefats(pmp %p, bp %p, fatbn %lu)\n", pmp, bp, fatbn);
322 	if (pmp->pm_flags & MSDOSFS_FATMIRROR) {
333 		if (fatbn != pmp->pm_fatblk || FAT12(pmp))
335 		else if (FAT16(pmp))
339 		for (i = 1; i < pmp->pm_FATs; i++) {
340 			fatbn += pmp->pm_FATsecs;
342 			bpn = getblk(pmp->pm_devvp, fatbn, bp->b_bcount,
350 			if (pmp->pm_mountp->mnt_flag & MNT_SYNCHRONOUS)
360 	if (pmp->pm_mountp->mnt_flag & MNT_SYNCHRONOUS)
386 usemap_alloc(struct msdosfsmount *pmp, u_long cn)
389 	MSDOSFS_ASSERT_MP_LOCKED(pmp);
391 	KASSERT(cn <= pmp->pm_maxcluster, ("cn too large %lu %lu", cn,
392 	    pmp->pm_maxcluster));
393 	KASSERT((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0,
395 	KASSERT((pmp->pm_inusemap[cn / N_INUSEBITS] &
398 	    (unsigned)pmp->pm_inusemap[cn / N_INUSEBITS]));
399 	pmp->pm_inusemap[cn / N_INUSEBITS] |= 1U << (cn % N_INUSEBITS);
400 	KASSERT(pmp->pm_freeclustercount > 0, ("usemap_alloc: too little"));
401 	pmp->pm_freeclustercount--;
402 	pmp->pm_flags |= MSDOSFS_FSIMOD;
406 usemap_free(struct msdosfsmount *pmp, u_long cn)
409 	MSDOSFS_ASSERT_MP_LOCKED(pmp);
411 	KASSERT(cn <= pmp->pm_maxcluster, ("cn too large %lu %lu", cn,
412 	    pmp->pm_maxcluster));
413 	KASSERT((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0,
415 	if ((pmp->pm_inusemap[cn / N_INUSEBITS] &
418 		    pmp->pm_mountp->mnt_stat.f_mntonname, cn, cn % N_INUSEBITS,
419 		    (unsigned)pmp->pm_inusemap[cn / N_INUSEBITS]);
420 		msdosfs_integrity_error(pmp);
423 	pmp->pm_freeclustercount++;
424 	pmp->pm_flags |= MSDOSFS_FSIMOD;
425 	pmp->pm_inusemap[cn / N_INUSEBITS] &= ~(1U << (cn % N_INUSEBITS));
430 clusterfree(struct msdosfsmount *pmp, u_long cluster)
435 	error = fatentry(FAT_GET_AND_SET, pmp, cluster, &oldcn, MSDOSFSFREE);
443 	MSDOSFS_LOCK_MP(pmp);
444 	error = usemap_free(pmp, cluster);
445 	MSDOSFS_UNLOCK_MP(pmp);
452  * pmp		- address of the msdosfsmount structure for the filesystem
468 fatentry(int function, struct msdosfsmount *pmp, u_long cn, u_long *oldcontents,
477 	printf("fatentry(func %d, pmp %p, clust %lu, oldcon %p, newcon %lx)\n",
478 	    function, pmp, cn, oldcontents, newcontents);
507 	if (cn < CLUST_FIRST || cn > pmp->pm_maxcluster)
510 	byteoffset = FATOFS(pmp, cn);
511 	fatblock(pmp, byteoffset, &bn, &bsize, &bo);
512 	error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
518 		if (FAT32(pmp))
522 		if (FAT12(pmp) & (cn & 1))
524 		readcn &= pmp->pm_fatmask;
526 		if ((readcn | ~pmp->pm_fatmask) >= CLUST_RSRVD)
527 			readcn |= ~pmp->pm_fatmask;
531 		switch (pmp->pm_fatmask) {
557 		updatefats(pmp, bp, bn);
559 		pmp->pm_fmod = 1;
569  * pmp	    - mount point
575 fatchain(struct msdosfsmount *pmp, u_long start, u_long count, u_long fillwith)
582 	printf("fatchain(pmp %p, start %lu, count %lu, fillwith %lx)\n",
583 	    pmp, start, count, fillwith);
588 	if (start < CLUST_FIRST || start + count - 1 > pmp->pm_maxcluster)
592 		byteoffset = FATOFS(pmp, start);
593 		fatblock(pmp, byteoffset, &bn, &bsize, &bo);
594 		error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
601 			switch (pmp->pm_fatmask) {
622 				readcn &= ~pmp->pm_fatmask;
623 				readcn |= newc & pmp->pm_fatmask;
631 		updatefats(pmp, bp, bn);
633 	pmp->pm_fmod = 1;
640  * pmp	 - mount point
645 chainlength(struct msdosfsmount *pmp, u_long start, u_long count)
651 	MSDOSFS_ASSERT_MP_LOCKED(pmp);
653 	if (start > pmp->pm_maxcluster)
655 	max_idx = pmp->pm_maxcluster / N_INUSEBITS;
658 	map = pmp->pm_inusemap[idx];
663 		if (start + len > pmp->pm_maxcluster)
664 			len = pmp->pm_maxcluster - start + 1;
670 		if (start + len > pmp->pm_maxcluster)
671 			len = pmp->pm_maxcluster - start + 1;
677 		map = pmp->pm_inusemap[idx];
685 	if (start + len > pmp->pm_maxcluster)
686 		len = pmp->pm_maxcluster - start + 1;
693  * pmp	      - mount point.
702 chainalloc(struct msdosfsmount *pmp, u_long start, u_long count,
708 	MSDOSFS_ASSERT_MP_LOCKED(pmp);
709 	KASSERT((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0,
713 		usemap_alloc(pmp, cl++);
714 	pmp->pm_nxtfree = start + count;
715 	if (pmp->pm_nxtfree > pmp->pm_maxcluster)
716 		pmp->pm_nxtfree = CLUST_FIRST;
717 	pmp->pm_flags |= MSDOSFS_FSIMOD;
718 	error = fatchain(pmp, start, count, fillwith);
721 			(void)usemap_free(pmp, cl++);
738  * pmp	      - mount point.
747 clusteralloc(struct msdosfsmount *pmp, u_long start, u_long count,
752 	MSDOSFS_LOCK_MP(pmp);
753 	error = clusteralloc1(pmp, start, count, fillwith, retcluster, got);
754 	MSDOSFS_UNLOCK_MP(pmp);
759 clusteralloc1(struct msdosfsmount *pmp, u_long start, u_long count,
767 	MSDOSFS_ASSERT_MP_LOCKED(pmp);
773 		if ((len = chainlength(pmp, start, count)) >= count)
774 			return (chainalloc(pmp, start, count, fillwith, retcluster, got));
778 	newst = pmp->pm_nxtfree;
781 	for (cn = newst; cn <= pmp->pm_maxcluster;) {
783 		map = pmp->pm_inusemap[idx];
787 			if ((l = chainlength(pmp, cn, count)) >= count)
788 				return (chainalloc(pmp, cn, count, fillwith, retcluster, got));
800 		map = pmp->pm_inusemap[idx];
804 			if ((l = chainlength(pmp, cn, count)) >= count)
805 				return (chainalloc(pmp, cn, count, fillwith, retcluster, got));
820 		return (chainalloc(pmp, start, len, fillwith, retcluster, got));
822 		return (chainalloc(pmp, foundcn, foundl, fillwith, retcluster, got));
828  * pmp		- address of the msdosfs mount structure for the filesystem
834 freeclusterchain(struct msdosfsmount *pmp, u_long cluster)
841 	MSDOSFS_LOCK_MP(pmp);
842 	while (cluster >= CLUST_FIRST && cluster <= pmp->pm_maxcluster) {
843 		byteoffset = FATOFS(pmp, cluster);
844 		fatblock(pmp, byteoffset, &bn, &bsize, &bo);
847 				updatefats(pmp, bp, lbn);
848 			error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
850 				MSDOSFS_UNLOCK_MP(pmp);
855 		error = usemap_free(pmp, cluster);
857 			updatefats(pmp, bp, lbn);
858 			MSDOSFS_UNLOCK_MP(pmp);
861 		switch (pmp->pm_fatmask) {
885 		cluster &= pmp->pm_fatmask;
886 		if ((cluster | ~pmp->pm_fatmask) >= CLUST_RSRVD)
887 			cluster |= pmp->pm_fatmask;
890 		updatefats(pmp, bp, bn);
891 	MSDOSFS_UNLOCK_MP(pmp);
900 fillinusemap(struct msdosfsmount *pmp)
906 	MSDOSFS_ASSERT_MP_LOCKED(pmp);
913 	for (cn = 0; cn < (pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS; cn++)
914 		pmp->pm_inusemap[cn] = FULL_RUN;
921 	pmp->pm_freeclustercount = 0;
922 	for (cn = 0; cn <= pmp->pm_maxcluster; cn++) {
923 		byteoffset = FATOFS(pmp, cn);
924 		bo = byteoffset % pmp->pm_fatblocksize;
929 			fatblock(pmp, byteoffset, &bn, &bsize, NULL);
930 			error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
934 		if (FAT32(pmp))
938 		if (FAT12(pmp) && (cn & 1))
940 		readcn &= pmp->pm_fatmask;
946 		if (cn == 0 && readcn != ((pmp->pm_fatmask & 0xffffff00) |
947 		    pmp->pm_bpb.bpbMedia)) {
955 			error = usemap_free(pmp, cn);
965 	for (cn = pmp->pm_maxcluster + 1; cn < (pmp->pm_maxcluster +
967 		pmp->pm_inusemap[cn / N_INUSEBITS] |= 1U << (cn % N_INUSEBITS);
994 	struct msdosfsmount *pmp = dep->de_pmp;
1039 		error = clusteralloc(pmp, cn, count, CLUST_EOFE, &cn, &got);
1058 			error = fatentry(FAT_SET, pmp,
1062 				clusterfree(pmp, cn);
1080 					bp = getblk(pmp->pm_devvp,
1081 					    cntobn(pmp, cn++),
1082 					    pmp->pm_bpcluster, 0, 0, 0);
1086 					    pmp->pm_bpcluster, 0, 0, 0);
1127  *	pmp	The MS-DOS volume to mark
1137 markvoldirty_upgrade(struct msdosfsmount *pmp, bool dirty, bool rw_upgrade)
1147 	if (FAT12(pmp))
1154 	if ((pmp->pm_flags & MSDOSFSMNT_RONLY) != 0 && !rw_upgrade)
1161 	byteoffset = FATOFS(pmp, 1);
1162 	fatblock(pmp, byteoffset, &bn, &bsize, &bo);
1163 	error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
1172 	if (FAT32(pmp)) {