makefs/msdos/msdosfs_fat.c

70 #define	SYNCHRONOUS_WRITES(pmp)	1
72 static int	chainalloc(struct msdosfsmount *pmp, u_long start,
75 static int	chainlength(struct msdosfsmount *pmp, u_long start,
77 static void	fatblock(struct msdosfsmount *pmp, u_long ofs, u_long *bnp,
79 static int	fatchain(struct msdosfsmount *pmp, u_long start, u_long count,
83 static void	updatefats(struct msdosfsmount *pmp, struct m_buf *bp,
86 		usemap_alloc(struct msdosfsmount *pmp, u_long cn);
88 		usemap_free(struct msdosfsmount *pmp, u_long cn);
89 static int	clusteralloc1(struct msdosfsmount *pmp, u_long start,
94 fatblock(struct msdosfsmount *pmp, u_long ofs, u_long *bnp, u_long *sizep,
99 	bn = ofs / pmp->pm_fatblocksize * pmp->pm_fatblocksec;
100 	size = MIN(pmp->pm_fatblocksec, pmp->pm_FATsecs - bn)
102 	bn += pmp->pm_fatblk + pmp->pm_curfat * pmp->pm_FATsecs;
109 		*bop = ofs % pmp->pm_fatblocksize;
143 	struct msdosfsmount *pmp = dep->de_pmp;
157 			if (de_cn2off(pmp, findcn) >= dep->de_FileSize) {
159 					*cnp = de_bn2cn(pmp, pmp->pm_rootdirsize);
163 				*bnp = pmp->pm_rootdirblk + de_cn2bn(pmp, findcn);
167 				*sp = MIN(pmp->pm_bpcluster,
168 				    dep->de_FileSize - de_cn2off(pmp, findcn));
181 		*sp = pmp->pm_bpcluster;
198 		if ((cn | ~pmp->pm_fatmask) >= CLUST_RSRVD)
200 		byteoffset = FATOFS(pmp, cn);
201 		fatblock(pmp, byteoffset, &bn, &bsize, &bo);
205 			error = bread((void *)pmp->pm_devvp, bn, bsize,
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);
304  * pmp	 - msdosfsmount structure for filesystem to update
309 updatefats(struct msdosfsmount *pmp, struct m_buf *bp, u_long fatbn)
315 	printf("updatefats(pmp %p, bp %p, fatbn %lu)\n", pmp, bp, fatbn);
318 	if (pmp->pm_flags & MSDOSFS_FATMIRROR) {
329 		if (fatbn != pmp->pm_fatblk || FAT12(pmp))
331 		else if (FAT16(pmp))
335 		for (i = 1; i < pmp->pm_FATs; i++) {
336 			fatbn += pmp->pm_FATsecs;
338 			bpn = getblk((void *)pmp->pm_devvp, fatbn,
346 			if (SYNCHRONOUS_WRITES(pmp))
356 	if (SYNCHRONOUS_WRITES(pmp))
382 usemap_alloc(struct msdosfsmount *pmp, u_long cn)
385 	assert(cn <= pmp->pm_maxcluster);
386 	assert((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0);
387 	assert((pmp->pm_inusemap[cn / N_INUSEBITS] & (1 << (cn % N_INUSEBITS)))
389 	assert(pmp->pm_freeclustercount > 0);
391 	pmp->pm_inusemap[cn / N_INUSEBITS] |= 1U << (cn % N_INUSEBITS);
392 	pmp->pm_freeclustercount--;
393 	pmp->pm_flags |= MSDOSFS_FSIMOD;
397 usemap_free(struct msdosfsmount *pmp, u_long cn)
400 	assert(cn <= pmp->pm_maxcluster);
401 	assert((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0);
402 	assert((pmp->pm_inusemap[cn / N_INUSEBITS] & (1 << (cn % N_INUSEBITS)))
405 	pmp->pm_freeclustercount++;
406 	pmp->pm_flags |= MSDOSFS_FSIMOD;
407 	pmp->pm_inusemap[cn / N_INUSEBITS] &= ~(1U << (cn % N_INUSEBITS));
411 clusterfree(struct msdosfsmount *pmp, u_long cluster)
416 	error = fatentry(FAT_GET_AND_SET, pmp, cluster, &oldcn, MSDOSFSFREE);
424 	usemap_free(pmp, cluster);
431  * pmp		- address of the msdosfsmount structure for the filesystem
447 fatentry(int function, struct msdosfsmount *pmp, u_long cn, u_long *oldcontents,
456 	printf("fatentry(func %d, pmp %p, clust %lu, oldcon %p, newcon %lx)\n",
457 	    function, pmp, cn, oldcontents, newcontents);
486 	if (cn < CLUST_FIRST || cn > pmp->pm_maxcluster)
489 	byteoffset = FATOFS(pmp, cn);
490 	fatblock(pmp, byteoffset, &bn, &bsize, &bo);
491 	error = bread((void *)pmp->pm_devvp, bn, bsize, NOCRED, &bp);
498 		if (FAT32(pmp))
502 		if (FAT12(pmp) & (cn & 1))
504 		readcn &= pmp->pm_fatmask;
506 		if ((readcn | ~pmp->pm_fatmask) >= CLUST_RSRVD)
507 			readcn |= ~pmp->pm_fatmask;
511 		switch (pmp->pm_fatmask) {
537 		updatefats(pmp, bp, bn);
539 		pmp->pm_fmod = 1;
549  * pmp	    - mount point
555 fatchain(struct msdosfsmount *pmp, u_long start, u_long count, u_long fillwith)
562 	printf("fatchain(pmp %p, start %lu, count %lu, fillwith %lx)\n",
563 	    pmp, start, count, fillwith);
568 	if (start < CLUST_FIRST || start + count - 1 > pmp->pm_maxcluster)
572 		byteoffset = FATOFS(pmp, start);
573 		fatblock(pmp, byteoffset, &bn, &bsize, &bo);
574 		error = bread((void *)pmp->pm_devvp, bn, bsize, NOCRED, &bp);
582 			switch (pmp->pm_fatmask) {
603 				readcn &= ~pmp->pm_fatmask;
604 				readcn |= newc & pmp->pm_fatmask;
612 		updatefats(pmp, bp, bn);
614 	pmp->pm_fmod = 1;
621  * pmp	 - mount point
626 chainlength(struct msdosfsmount *pmp, u_long start, u_long count)
632 	if (start > pmp->pm_maxcluster)
634 	max_idx = pmp->pm_maxcluster / N_INUSEBITS;
637 	map = pmp->pm_inusemap[idx];
642 		if (start + len > pmp->pm_maxcluster)
643 			len = pmp->pm_maxcluster - start + 1;
649 		if (start + len > pmp->pm_maxcluster)
650 			len = pmp->pm_maxcluster - start + 1;
656 		map = pmp->pm_inusemap[idx];
664 	if (start + len > pmp->pm_maxcluster)
665 		len = pmp->pm_maxcluster - start + 1;
672  * pmp	      - mount point.
681 chainalloc(struct msdosfsmount *pmp, u_long start, u_long count,
687 	assert((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0);
690 		usemap_alloc(pmp, cl++);
691 	pmp->pm_nxtfree = start + count;
692 	if (pmp->pm_nxtfree > pmp->pm_maxcluster)
693 		pmp->pm_nxtfree = CLUST_FIRST;
694 	pmp->pm_flags |= MSDOSFS_FSIMOD;
695 	error = fatchain(pmp, start, count, fillwith);
698 			usemap_free(pmp, cl++);
715  * pmp	      - mount point.
724 clusteralloc(struct msdosfsmount *pmp, u_long start, u_long count,
729 	error = clusteralloc1(pmp, start, count, fillwith, retcluster, got);
734 clusteralloc1(struct msdosfsmount *pmp, u_long start, u_long count,
745 		if ((len = chainlength(pmp, start, count)) >= count)
746 			return (chainalloc(pmp, start, count, fillwith, retcluster, got));
750 	newst = pmp->pm_nxtfree;
753 	for (cn = newst; cn <= pmp->pm_maxcluster;) {
755 		map = pmp->pm_inusemap[idx];
759 			if ((l = chainlength(pmp, cn, count)) >= count)
760 				return (chainalloc(pmp, cn, count, fillwith, retcluster, got));
772 		map = pmp->pm_inusemap[idx];
776 			if ((l = chainlength(pmp, cn, count)) >= count)
777 				return (chainalloc(pmp, cn, count, fillwith, retcluster, got));
792 		return (chainalloc(pmp, start, len, fillwith, retcluster, got));
794 		return (chainalloc(pmp, foundcn, foundl, fillwith, retcluster, got));
801  * pmp		- address of the msdosfs mount structure for the filesystem
807 freeclusterchain(struct msdosfsmount *pmp, u_long cluster)
814 	while (cluster >= CLUST_FIRST && cluster <= pmp->pm_maxcluster) {
815 		byteoffset = FATOFS(pmp, cluster);
816 		fatblock(pmp, byteoffset, &bn, &bsize, &bo);
819 				updatefats(pmp, bp, lbn);
820 			error = bread((void *)pmp->pm_devvp, bn, bsize,
828 		usemap_free(pmp, cluster);
829 		switch (pmp->pm_fatmask) {
853 		cluster &= pmp->pm_fatmask;
854 		if ((cluster | ~pmp->pm_fatmask) >= CLUST_RSRVD)
855 			cluster |= pmp->pm_fatmask;
858 		updatefats(pmp, bp, bn);
867 fillinusemap(struct msdosfsmount *pmp)
879 	for (cn = 0; cn < (pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS; cn++)
880 		pmp->pm_inusemap[cn] = FULL_RUN;
887 	pmp->pm_freeclustercount = 0;
888 	for (cn = 0; cn <= pmp->pm_maxcluster; cn++) {
889 		byteoffset = FATOFS(pmp, cn);
890 		bo = byteoffset % pmp->pm_fatblocksize;
895 			fatblock(pmp, byteoffset, &bn, &bsize, NULL);
896 			error = bread((void *)pmp->pm_devvp, bn, bsize,
901 		if (FAT32(pmp))
905 		if (FAT12(pmp) && (cn & 1))
907 		readcn &= pmp->pm_fatmask;
913 		if (cn == 0 && readcn != ((pmp->pm_fatmask & 0xffffff00) |
914 		    pmp->pm_bpb.bpbMedia)) {
922 			usemap_free(pmp, cn);
927 	for (cn = pmp->pm_maxcluster + 1; cn < (pmp->pm_maxcluster +
929 		pmp->pm_inusemap[cn / N_INUSEBITS] |= 1U << (cn % N_INUSEBITS);
956 	struct msdosfsmount *pmp = dep->de_pmp;
1000 		error = clusteralloc(pmp, cn, count, CLUST_EOFE, &cn, &got);
1019 			error = fatentry(FAT_SET, pmp,
1023 				clusterfree(pmp, cn);
1038 				bp = getblk((void *)pmp->pm_devvp,
1039 				    cntobn(pmp, cn++),
1040 				    pmp->pm_bpcluster, 0, 0, 0);