fs/msdosfs/msdosfs_fat.c

63 static int	chainalloc(struct msdosfsmount *pmp, u_long start,
66 static int	chainlength(struct msdosfsmount *pmp, u_long start,
68 static void	fatblock(struct msdosfsmount *pmp, u_long ofs, u_long *bnp,
70 static int	fatchain(struct msdosfsmount *pmp, u_long start, u_long count,
74 static void	updatefats(struct msdosfsmount *pmp, struct buf *bp,
77 		usemap_alloc(struct msdosfsmount *pmp, u_long cn);
79 		usemap_free(struct msdosfsmount *pmp, u_long cn);
80 static int	clusteralloc1(struct msdosfsmount *pmp, u_long start,
85 fatblock(pmp, ofs, bnp, sizep, bop)
86 	struct msdosfsmount *pmp;
94 	bn = ofs / pmp->pm_fatblocksize * pmp->pm_fatblocksec;
95 	size = min(pmp->pm_fatblocksec, pmp->pm_FATsecs - bn)
97 	bn += pmp->pm_fatblk + pmp->pm_curfat * pmp->pm_FATsecs;
104 		*bop = ofs % pmp->pm_fatblocksize;
142 	struct msdosfsmount *pmp = dep->de_pmp;
158 			if (de_cn2off(pmp, findcn) >= dep->de_FileSize) {
160 					*cnp = de_bn2cn(pmp, pmp->pm_rootdirsize);
164 				*bnp = pmp->pm_rootdirblk + de_cn2bn(pmp, findcn);
168 				*sp = min(pmp->pm_bpcluster,
169 				    dep->de_FileSize - de_cn2off(pmp, findcn));
182 		*sp = pmp->pm_bpcluster;
199 		if ((cn | ~pmp->pm_fatmask) >= CLUST_RSRVD)
201 		byteoffset = FATOFS(pmp, cn);
202 		fatblock(pmp, byteoffset, &bn, &bsize, &bo);
206 			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);
314  * pmp	 - msdosfsmount structure for filesystem to update
319 updatefats(pmp, bp, fatbn)
320 	struct msdosfsmount *pmp;
328 	printf("updatefats(pmp %p, bp %p, fatbn %lu)\n", pmp, bp, fatbn);
331 	if (pmp->pm_flags & MSDOSFS_FATMIRROR) {
342 		if (fatbn != pmp->pm_fatblk || FAT12(pmp))
344 		else if (FAT16(pmp))
348 		for (i = 1; i < pmp->pm_FATs; i++) {
349 			fatbn += pmp->pm_FATsecs;
351 			bpn = getblk(pmp->pm_devvp, fatbn, bp->b_bcount,
359 			if (pmp->pm_mountp->mnt_flag & MNT_SYNCHRONOUS)
369 	if (pmp->pm_mountp->mnt_flag & MNT_SYNCHRONOUS)
395 usemap_alloc(pmp, cn)
396 	struct msdosfsmount *pmp;
400 	MSDOSFS_ASSERT_MP_LOCKED(pmp);
402 	KASSERT((pmp->pm_inusemap[cn / N_INUSEBITS] & (1 << (cn % N_INUSEBITS)))
404 		(unsigned)pmp->pm_inusemap[cn / N_INUSEBITS]));
405 	pmp->pm_inusemap[cn / N_INUSEBITS] |= 1 << (cn % N_INUSEBITS);
406 	KASSERT(pmp->pm_freeclustercount > 0, ("usemap_alloc: too little"));
407 	pmp->pm_freeclustercount--;
408 	pmp->pm_flags |= MSDOSFS_FSIMOD;
412 usemap_free(pmp, cn)
413 	struct msdosfsmount *pmp;
417 	MSDOSFS_ASSERT_MP_LOCKED(pmp);
418 	pmp->pm_freeclustercount++;
419 	pmp->pm_flags |= MSDOSFS_FSIMOD;
420 	KASSERT((pmp->pm_inusemap[cn / N_INUSEBITS] & (1 << (cn % N_INUSEBITS)))
422 		(unsigned)pmp->pm_inusemap[cn / N_INUSEBITS]));
423 	pmp->pm_inusemap[cn / N_INUSEBITS] &= ~(1 << (cn % N_INUSEBITS));
427 clusterfree(pmp, cluster, oldcnp)
428 	struct msdosfsmount *pmp;
435 	error = fatentry(FAT_GET_AND_SET, pmp, cluster, &oldcn, MSDOSFSFREE);
443 	MSDOSFS_LOCK_MP(pmp);
444 	usemap_free(pmp, cluster);
445 	MSDOSFS_UNLOCK_MP(pmp);
455  * pmp		- address of the msdosfsmount structure for the filesystem
471 fatentry(function, pmp, cn, oldcontents, newcontents)
473 	struct msdosfsmount *pmp;
484 	printf("fatentry(func %d, pmp %p, clust %lu, oldcon %p, newcon %lx)\n",
485 	    function, pmp, cn, oldcontents, newcontents);
514 	if (cn < CLUST_FIRST || cn > pmp->pm_maxcluster)
517 	byteoffset = FATOFS(pmp, cn);
518 	fatblock(pmp, byteoffset, &bn, &bsize, &bo);
519 	error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
526 		if (FAT32(pmp))
530 		if (FAT12(pmp) & (cn & 1))
532 		readcn &= pmp->pm_fatmask;
534 		if ((readcn | ~pmp->pm_fatmask) >= CLUST_RSRVD)
535 			readcn |= ~pmp->pm_fatmask;
539 		switch (pmp->pm_fatmask) {
565 		updatefats(pmp, bp, bn);
567 		pmp->pm_fmod = 1;
577  * pmp	    - mount point
583 fatchain(pmp, start, count, fillwith)
584 	struct msdosfsmount *pmp;
594 	printf("fatchain(pmp %p, start %lu, count %lu, fillwith %lx)\n",
595 	    pmp, start, count, fillwith);
600 	if (start < CLUST_FIRST || start + count - 1 > pmp->pm_maxcluster)
604 		byteoffset = FATOFS(pmp, start);
605 		fatblock(pmp, byteoffset, &bn, &bsize, &bo);
606 		error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
614 			switch (pmp->pm_fatmask) {
635 				readcn &= ~pmp->pm_fatmask;
636 				readcn |= newc & pmp->pm_fatmask;
644 		updatefats(pmp, bp, bn);
646 	pmp->pm_fmod = 1;
653  * pmp	 - mount point
658 chainlength(pmp, start, count)
659 	struct msdosfsmount *pmp;
667 	MSDOSFS_ASSERT_MP_LOCKED(pmp);
669 	max_idx = pmp->pm_maxcluster / N_INUSEBITS;
672 	map = pmp->pm_inusemap[idx];
684 		map = pmp->pm_inusemap[idx];
697  * pmp	      - mount point.
706 chainalloc(pmp, start, count, fillwith, retcluster, got)
707 	struct msdosfsmount *pmp;
717 	MSDOSFS_ASSERT_MP_LOCKED(pmp);
720 		usemap_alloc(pmp, cl++);
721 	pmp->pm_nxtfree = start + count;
722 	if (pmp->pm_nxtfree > pmp->pm_maxcluster)
723 		pmp->pm_nxtfree = CLUST_FIRST;
724 	pmp->pm_flags |= MSDOSFS_FSIMOD;
725 	error = fatchain(pmp, start, count, fillwith);
742  * pmp	      - mount point.
751 clusteralloc(struct msdosfsmount *pmp, u_long start, u_long count,
756 	MSDOSFS_LOCK_MP(pmp);
757 	error = clusteralloc1(pmp, start, count, fillwith, retcluster, got);
758 	MSDOSFS_UNLOCK_MP(pmp);
763 clusteralloc1(struct msdosfsmount *pmp, u_long start, u_long count,
771 	MSDOSFS_ASSERT_MP_LOCKED(pmp);
777 		if ((len = chainlength(pmp, start, count)) >= count)
778 			return (chainalloc(pmp, start, count, fillwith, retcluster, got));
782 	newst = pmp->pm_nxtfree;
785 	for (cn = newst; cn <= pmp->pm_maxcluster;) {
787 		map = pmp->pm_inusemap[idx];
791 			if ((l = chainlength(pmp, cn, count)) >= count)
792 				return (chainalloc(pmp, cn, count, fillwith, retcluster, got));
804 		map = pmp->pm_inusemap[idx];
808 			if ((l = chainlength(pmp, cn, count)) >= count)
809 				return (chainalloc(pmp, cn, count, fillwith, retcluster, got));
824 		return (chainalloc(pmp, start, len, fillwith, retcluster, got));
826 		return (chainalloc(pmp, foundcn, foundl, fillwith, retcluster, got));
833  * pmp		- address of the msdosfs mount structure for the filesystem
839 freeclusterchain(pmp, cluster)
840 	struct msdosfsmount *pmp;
848 	MSDOSFS_LOCK_MP(pmp);
849 	while (cluster >= CLUST_FIRST && cluster <= pmp->pm_maxcluster) {
850 		byteoffset = FATOFS(pmp, cluster);
851 		fatblock(pmp, byteoffset, &bn, &bsize, &bo);
854 				updatefats(pmp, bp, lbn);
855 			error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
858 				MSDOSFS_UNLOCK_MP(pmp);
863 		usemap_free(pmp, cluster);
864 		switch (pmp->pm_fatmask) {
888 		cluster &= pmp->pm_fatmask;
889 		if ((cluster | ~pmp->pm_fatmask) >= CLUST_RSRVD)
890 			cluster |= pmp->pm_fatmask;
893 		updatefats(pmp, bp, bn);
894 	MSDOSFS_UNLOCK_MP(pmp);
903 fillinusemap(pmp)
904 	struct msdosfsmount *pmp;
911 	MSDOSFS_ASSERT_MP_LOCKED(pmp);
917 	for (cn = 0; cn < (pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS; cn++)
918 		pmp->pm_inusemap[cn] = (u_int)-1;
925 	pmp->pm_freeclustercount = 0;
926 	for (cn = CLUST_FIRST; cn <= pmp->pm_maxcluster; cn++) {
927 		byteoffset = FATOFS(pmp, cn);
928 		bo = byteoffset % pmp->pm_fatblocksize;
933 			fatblock(pmp, byteoffset, &bn, &bsize, NULL);
934 			error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
940 		if (FAT32(pmp))
944 		if (FAT12(pmp) && (cn & 1))
946 		readcn &= pmp->pm_fatmask;
949 			usemap_free(pmp, cn);
982 	struct msdosfsmount *pmp = dep->de_pmp;
1027 		error = clusteralloc(pmp, cn, count, CLUST_EOFE, &cn, &got);
1046 			error = fatentry(FAT_SET, pmp,
1050 				clusterfree(pmp, cn, NULL);
1068 					bp = getblk(pmp->pm_devvp,
1069 					    cntobn(pmp, cn++),
1070 					    pmp->pm_bpcluster, 0, 0, 0);
1074 					    pmp->pm_bpcluster, 0, 0, 0);
1111  *	pmp	The MS-DOS volume to mark
1121 markvoldirty(struct msdosfsmount *pmp, int dirty)
1131 	if (FAT12(pmp))
1135 	if (pmp->pm_flags & MSDOSFSMNT_RONLY)
1142 	byteoffset = FATOFS(pmp, 1);
1143 	fatblock(pmp, byteoffset, &bn, &bsize, &bo);
1144 	error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
1155 	if (FAT32(pmp)) {