86 		usemap_alloc(struct msdosfsmount *pmp, u_long cn);
88 		usemap_free(struct msdosfsmount *pmp, u_long cn);
136 	u_long cn;  in pcbmap()  local
148 	cn = dep->de_StartCluster;  in pcbmap()
155 	if (cn == MSDOSFSROOT) {  in pcbmap()
189 	fc_lookup(dep, findcn, &i, &cn);  in pcbmap()
198 		if ((cn | ~pmp->pm_fatmask) >= CLUST_RSRVD)  in pcbmap()
200 		byteoffset = FATOFS(pmp, cn);  in pcbmap()
213 		prevcn = cn;  in pcbmap()
220 			cn = getulong(bp->b_data + bo);  in pcbmap()
222 			cn = getushort(bp->b_data + bo);  in pcbmap()
224 			cn >>= 4;  in pcbmap()
225 		cn &= pmp->pm_fatmask;  in pcbmap()
233 		if ((cn | ~pmp->pm_fatmask) >= CLUST_RSRVD)  in pcbmap()
234 			cn |= ~pmp->pm_fatmask;  in pcbmap()
237 	if (!MSDOSFSEOF(pmp, cn)) {  in pcbmap()
241 			*bnp = cntobn(pmp, cn);  in pcbmap()
243 			*cnp = cn;  in pcbmap()
244 		fc_setcache(dep, FC_LASTMAP, i, cn);  in pcbmap()
266 	u_long cn;  in fc_lookup()  local
270 		cn = dep->de_fc[i].fc_frcn;  in fc_lookup()
271 		if (cn != FCE_EMPTY && cn <= findcn) {  in fc_lookup()
272 			if (closest == NULL || cn > closest->fc_frcn)  in fc_lookup()
382 usemap_alloc(struct msdosfsmount *pmp, u_long cn)  in usemap_alloc()  argument
385 	assert(cn <= pmp->pm_maxcluster);  in usemap_alloc()
387 	assert((pmp->pm_inusemap[cn / N_INUSEBITS] & (1 << (cn % N_INUSEBITS)))  in usemap_alloc()
391 	pmp->pm_inusemap[cn / N_INUSEBITS] |= 1U << (cn % N_INUSEBITS);  in usemap_alloc()
397 usemap_free(struct msdosfsmount *pmp, u_long cn)  in usemap_free()  argument
400 	assert(cn <= pmp->pm_maxcluster);  in usemap_free()
402 	assert((pmp->pm_inusemap[cn / N_INUSEBITS] & (1 << (cn % N_INUSEBITS)))  in usemap_free()
407 	pmp->pm_inusemap[cn / N_INUSEBITS] &= ~(1U << (cn % N_INUSEBITS));  in usemap_free()
433  * cn		- which cluster is of interest
447 fatentry(int function, struct msdosfsmount *pmp, u_long cn, u_long *oldcontents,  in fatentry()  argument
457 	    function, pmp, cn, oldcontents, newcontents);  in fatentry()
486 	if (cn < CLUST_FIRST || cn > pmp->pm_maxcluster)  in fatentry()
489 	byteoffset = FATOFS(pmp, cn);  in fatentry()
502 		if (FAT12(pmp) & (cn & 1))  in fatentry()
514 			if (cn & 1) {  in fatentry()
738 	u_long len, newst, foundl, cn, l;  in clusteralloc1()  local
753 	for (cn = newst; cn <= pmp->pm_maxcluster;) {  in clusteralloc1()
754 		idx = cn / N_INUSEBITS;  in clusteralloc1()
756 		map |= (1U << (cn % N_INUSEBITS)) - 1;  in clusteralloc1()
758 			cn = idx * N_INUSEBITS + ffs(map ^ FULL_RUN) - 1;  in clusteralloc1()
759 			if ((l = chainlength(pmp, cn, count)) >= count)  in clusteralloc1()
760 				return (chainalloc(pmp, cn, count, fillwith, retcluster, got));  in clusteralloc1()
762 				foundcn = cn;  in clusteralloc1()
765 			cn += l + 1;  in clusteralloc1()
768 		cn += N_INUSEBITS - cn % N_INUSEBITS;  in clusteralloc1()
770 	for (cn = 0; cn < newst;) {  in clusteralloc1()
771 		idx = cn / N_INUSEBITS;  in clusteralloc1()
773 		map |= (1U << (cn % N_INUSEBITS)) - 1;  in clusteralloc1()
775 			cn = idx * N_INUSEBITS + ffs(map ^ FULL_RUN) - 1;  in clusteralloc1()
776 			if ((l = chainlength(pmp, cn, count)) >= count)  in clusteralloc1()
777 				return (chainalloc(pmp, cn, count, fillwith, retcluster, got));  in clusteralloc1()
779 				foundcn = cn;  in clusteralloc1()
782 			cn += l + 1;  in clusteralloc1()
785 		cn += N_INUSEBITS - cn % N_INUSEBITS;  in clusteralloc1()
870 	u_long bn, bo, bsize, byteoffset, cn, readcn;  in fillinusemap()  local
879 	for (cn = 0; cn < (pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS; cn++)  in fillinusemap()
880 		pmp->pm_inusemap[cn] = FULL_RUN;  in fillinusemap()
888 	for (cn = 0; cn <= pmp->pm_maxcluster; cn++) {  in fillinusemap()
889 		byteoffset = FATOFS(pmp, cn);  in fillinusemap()
905 		if (FAT12(pmp) && (cn & 1))  in fillinusemap()
913 		if (cn == 0 && readcn != ((pmp->pm_fatmask & 0xffffff00) |  in fillinusemap()
922 			usemap_free(pmp, cn);  in fillinusemap()
927 	for (cn = pmp->pm_maxcluster + 1; cn < (pmp->pm_maxcluster +  in fillinusemap()
928 	    N_INUSEBITS) / N_INUSEBITS; cn++)  in fillinusemap()
929 		pmp->pm_inusemap[cn / N_INUSEBITS] |= 1U << (cn % N_INUSEBITS);  in fillinusemap()
955 	u_long cn, got;  in m_extendfile()  local
976 		error = pcbmap(dep, 0xffff, 0, &cn, 0);  in m_extendfile()
997 			cn = 0;  in m_extendfile()
999 			cn = dep->de_fc[FC_LASTFC].fc_fsrcn + 1;  in m_extendfile()
1000 		error = clusteralloc(pmp, cn, count, CLUST_EOFE, &cn, &got);  in m_extendfile()
1011 			*ncp = cn;  in m_extendfile()
1016 			dep->de_StartCluster = cn;  in m_extendfile()
1021 					 0, cn);  in m_extendfile()
1023 				clusterfree(pmp, cn);  in m_extendfile()
1033 		fc_setcache(dep, FC_LASTFC, frcn + got - 1, cn + got - 1);  in m_extendfile()
1039 				    cntobn(pmp, cn++),  in m_extendfile()