1/*
2 *  linux/fs/hpfs/alloc.c
3 *
4 *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
5 *
6 *  HPFS bitmap operations
7 */
8
9#include "hpfs_fn.h"
10
11static void hpfs_claim_alloc(struct super_block *s, secno sec)
12{
13	struct hpfs_sb_info *sbi = hpfs_sb(s);
14	if (sbi->sb_n_free != (unsigned)-1) {
15		if (unlikely(!sbi->sb_n_free)) {
16			hpfs_error(s, "free count underflow, allocating sector %08x", sec);
17			sbi->sb_n_free = -1;
18			return;
19		}
20		sbi->sb_n_free--;
21	}
22}
23
24static void hpfs_claim_free(struct super_block *s, secno sec)
25{
26	struct hpfs_sb_info *sbi = hpfs_sb(s);
27	if (sbi->sb_n_free != (unsigned)-1) {
28		if (unlikely(sbi->sb_n_free >= sbi->sb_fs_size)) {
29			hpfs_error(s, "free count overflow, freeing sector %08x", sec);
30			sbi->sb_n_free = -1;
31			return;
32		}
33		sbi->sb_n_free++;
34	}
35}
36
37static void hpfs_claim_dirband_alloc(struct super_block *s, secno sec)
38{
39	struct hpfs_sb_info *sbi = hpfs_sb(s);
40	if (sbi->sb_n_free_dnodes != (unsigned)-1) {
41		if (unlikely(!sbi->sb_n_free_dnodes)) {
42			hpfs_error(s, "dirband free count underflow, allocating sector %08x", sec);
43			sbi->sb_n_free_dnodes = -1;
44			return;
45		}
46		sbi->sb_n_free_dnodes--;
47	}
48}
49
50static void hpfs_claim_dirband_free(struct super_block *s, secno sec)
51{
52	struct hpfs_sb_info *sbi = hpfs_sb(s);
53	if (sbi->sb_n_free_dnodes != (unsigned)-1) {
54		if (unlikely(sbi->sb_n_free_dnodes >= sbi->sb_dirband_size / 4)) {
55			hpfs_error(s, "dirband free count overflow, freeing sector %08x", sec);
56			sbi->sb_n_free_dnodes = -1;
57			return;
58		}
59		sbi->sb_n_free_dnodes++;
60	}
61}
62
63/*
64 * Check if a sector is allocated in bitmap
65 * This is really slow. Turned on only if chk==2
66 */
67
68static int chk_if_allocated(struct super_block *s, secno sec, char *msg)
69{
70	struct quad_buffer_head qbh;
71	__le32 *bmp;
72	if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "chk"))) goto fail;
73	if ((le32_to_cpu(bmp[(sec & 0x3fff) >> 5]) >> (sec & 0x1f)) & 1) {
74		hpfs_error(s, "sector '%s' - %08x not allocated in bitmap", msg, sec);
75		goto fail1;
76	}
77	hpfs_brelse4(&qbh);
78	if (sec >= hpfs_sb(s)->sb_dirband_start && sec < hpfs_sb(s)->sb_dirband_start + hpfs_sb(s)->sb_dirband_size) {
79		unsigned ssec = (sec - hpfs_sb(s)->sb_dirband_start) / 4;
80		if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) goto fail;
81		if ((le32_to_cpu(bmp[ssec >> 5]) >> (ssec & 0x1f)) & 1) {
82			hpfs_error(s, "sector '%s' - %08x not allocated in directory bitmap", msg, sec);
83			goto fail1;
84		}
85		hpfs_brelse4(&qbh);
86	}
87	return 0;
88	fail1:
89	hpfs_brelse4(&qbh);
90	fail:
91	return 1;
92}
93
94/*
95 * Check if sector(s) have proper number and additionally check if they're
96 * allocated in bitmap.
97 */
98
99int hpfs_chk_sectors(struct super_block *s, secno start, int len, char *msg)
100{
101	if (start + len < start || start < 0x12 ||
102	    start + len > hpfs_sb(s)->sb_fs_size) {
103	    	hpfs_error(s, "sector(s) '%s' badly placed at %08x", msg, start);
104		return 1;
105	}
106	if (hpfs_sb(s)->sb_chk>=2) {
107		int i;
108		for (i = 0; i < len; i++)
109			if (chk_if_allocated(s, start + i, msg)) return 1;
110	}
111	return 0;
112}
113
114static secno alloc_in_bmp(struct super_block *s, secno near, unsigned n, unsigned forward)
115{
116	struct quad_buffer_head qbh;
117	__le32 *bmp;
118	unsigned bs = near & ~0x3fff;
119	unsigned nr = (near & 0x3fff) & ~(n - 1);
120	/*unsigned mnr;*/
121	unsigned i, q;
122	int a, b;
123	secno ret = 0;
124	if (n != 1 && n != 4) {
125		hpfs_error(s, "Bad allocation size: %d", n);
126		return 0;
127	}
128	if (bs != ~0x3fff) {
129		if (!(bmp = hpfs_map_bitmap(s, near >> 14, &qbh, "aib"))) goto uls;
130	} else {
131		if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) goto uls;
132	}
133	if (!tstbits(bmp, nr, n + forward)) {
134		ret = bs + nr;
135		goto rt;
136	}
137	q = nr + n; b = 0;
138	while ((a = tstbits(bmp, q, n + forward)) != 0) {
139		q += a;
140		if (n != 1) q = ((q-1)&~(n-1))+n;
141		if (!b) {
142			if (q>>5 != nr>>5) {
143				b = 1;
144				q = nr & 0x1f;
145			}
146		} else if (q > nr) break;
147	}
148	if (!a) {
149		ret = bs + q;
150		goto rt;
151	}
152	nr >>= 5;
153	/*for (i = nr + 1; i != nr; i++, i &= 0x1ff) */
154	i = nr;
155	do {
156		if (!le32_to_cpu(bmp[i])) goto cont;
157		if (n + forward >= 0x3f && le32_to_cpu(bmp[i]) != 0xffffffff) goto cont;
158		q = i<<5;
159		if (i > 0) {
160			unsigned k = le32_to_cpu(bmp[i-1]);
161			while (k & 0x80000000) {
162				q--; k <<= 1;
163			}
164		}
165		if (n != 1) q = ((q-1)&~(n-1))+n;
166		while ((a = tstbits(bmp, q, n + forward)) != 0) {
167			q += a;
168			if (n != 1) q = ((q-1)&~(n-1))+n;
169			if (q>>5 > i) break;
170		}
171		if (!a) {
172			ret = bs + q;
173			goto rt;
174		}
175		cont:
176		i++, i &= 0x1ff;
177	} while (i != nr);
178	rt:
179	if (ret) {
180		if (hpfs_sb(s)->sb_chk && ((ret >> 14) != (bs >> 14) || (le32_to_cpu(bmp[(ret & 0x3fff) >> 5]) | ~(((1 << n) - 1) << (ret & 0x1f))) != 0xffffffff)) {
181			hpfs_error(s, "Allocation doesn't work! Wanted %d, allocated at %08x", n, ret);
182			ret = 0;
183			goto b;
184		}
185		bmp[(ret & 0x3fff) >> 5] &= cpu_to_le32(~(((1 << n) - 1) << (ret & 0x1f)));
186		hpfs_mark_4buffers_dirty(&qbh);
187	}
188	b:
189	hpfs_brelse4(&qbh);
190	uls:
191	return ret;
192}
193
194/*
195 * Allocation strategy:	1) search place near the sector specified
196 *			2) search bitmap where free sectors last found
197 *			3) search all bitmaps
198 *			4) search all bitmaps ignoring number of pre-allocated
199 *				sectors
200 */
201
202secno hpfs_alloc_sector(struct super_block *s, secno near, unsigned n, int forward)
203{
204	secno sec;
205	int i;
206	unsigned n_bmps;
207	struct hpfs_sb_info *sbi = hpfs_sb(s);
208	int f_p = 0;
209	int near_bmp;
210	if (forward < 0) {
211		forward = -forward;
212		f_p = 1;
213	}
214	n_bmps = (sbi->sb_fs_size + 0x4000 - 1) >> 14;
215	if (near && near < sbi->sb_fs_size) {
216		if ((sec = alloc_in_bmp(s, near, n, f_p ? forward : forward/4))) goto ret;
217		near_bmp = near >> 14;
218	} else near_bmp = n_bmps / 2;
219	/*
220	if (b != -1) {
221		if ((sec = alloc_in_bmp(s, b<<14, n, f_p ? forward : forward/2))) {
222			b &= 0x0fffffff;
223			goto ret;
224		}
225		if (b > 0x10000000) if ((sec = alloc_in_bmp(s, (b&0xfffffff)<<14, n, f_p ? forward : 0))) goto ret;
226	*/
227	if (!f_p) if (forward > sbi->sb_max_fwd_alloc) forward = sbi->sb_max_fwd_alloc;
228	less_fwd:
229	for (i = 0; i < n_bmps; i++) {
230		if (near_bmp+i < n_bmps && ((sec = alloc_in_bmp(s, (near_bmp+i) << 14, n, forward)))) {
231			sbi->sb_c_bitmap = near_bmp+i;
232			goto ret;
233		}
234		if (!forward) {
235			if (near_bmp-i-1 >= 0 && ((sec = alloc_in_bmp(s, (near_bmp-i-1) << 14, n, forward)))) {
236				sbi->sb_c_bitmap = near_bmp-i-1;
237				goto ret;
238			}
239		} else {
240			if (near_bmp+i >= n_bmps && ((sec = alloc_in_bmp(s, (near_bmp+i-n_bmps) << 14, n, forward)))) {
241				sbi->sb_c_bitmap = near_bmp+i-n_bmps;
242				goto ret;
243			}
244		}
245		if (i == 1 && sbi->sb_c_bitmap != -1 && ((sec = alloc_in_bmp(s, (sbi->sb_c_bitmap) << 14, n, forward)))) {
246			goto ret;
247		}
248	}
249	if (!f_p) {
250		if (forward) {
251			sbi->sb_max_fwd_alloc = forward * 3 / 4;
252			forward /= 2;
253			goto less_fwd;
254		}
255	}
256	sec = 0;
257	ret:
258	if (sec) {
259		i = 0;
260		do
261			hpfs_claim_alloc(s, sec + i);
262		while (unlikely(++i < n));
263	}
264	if (sec && f_p) {
265		for (i = 0; i < forward; i++) {
266			if (!hpfs_alloc_if_possible(s, sec + n + i)) {
267				hpfs_error(s, "Prealloc doesn't work! Wanted %d, allocated at %08x, can't allocate %d", forward, sec, i);
268				sec = 0;
269				break;
270			}
271		}
272	}
273	return sec;
274}
275
276static secno alloc_in_dirband(struct super_block *s, secno near)
277{
278	unsigned nr = near;
279	secno sec;
280	struct hpfs_sb_info *sbi = hpfs_sb(s);
281	if (nr < sbi->sb_dirband_start)
282		nr = sbi->sb_dirband_start;
283	if (nr >= sbi->sb_dirband_start + sbi->sb_dirband_size)
284		nr = sbi->sb_dirband_start + sbi->sb_dirband_size - 4;
285	nr -= sbi->sb_dirband_start;
286	nr >>= 2;
287	sec = alloc_in_bmp(s, (~0x3fff) | nr, 1, 0);
288	if (!sec) return 0;
289	hpfs_claim_dirband_alloc(s, sec);
290	return ((sec & 0x3fff) << 2) + sbi->sb_dirband_start;
291}
292
293/* Alloc sector if it's free */
294
295int hpfs_alloc_if_possible(struct super_block *s, secno sec)
296{
297	struct quad_buffer_head qbh;
298	__le32 *bmp;
299	if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "aip"))) goto end;
300	if (le32_to_cpu(bmp[(sec & 0x3fff) >> 5]) & (1 << (sec & 0x1f))) {
301		bmp[(sec & 0x3fff) >> 5] &= cpu_to_le32(~(1 << (sec & 0x1f)));
302		hpfs_mark_4buffers_dirty(&qbh);
303		hpfs_brelse4(&qbh);
304		hpfs_claim_alloc(s, sec);
305		return 1;
306	}
307	hpfs_brelse4(&qbh);
308	end:
309	return 0;
310}
311
312/* Free sectors in bitmaps */
313
314void hpfs_free_sectors(struct super_block *s, secno sec, unsigned n)
315{
316	struct quad_buffer_head qbh;
317	__le32 *bmp;
318	struct hpfs_sb_info *sbi = hpfs_sb(s);
319	/*pr_info("2 - ");*/
320	if (!n) return;
321	if (sec < 0x12) {
322		hpfs_error(s, "Trying to free reserved sector %08x", sec);
323		return;
324	}
325	sbi->sb_max_fwd_alloc += n > 0xffff ? 0xffff : n;
326	if (sbi->sb_max_fwd_alloc > 0xffffff) sbi->sb_max_fwd_alloc = 0xffffff;
327	new_map:
328	if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "free"))) {
329		return;
330	}
331	new_tst:
332	if ((le32_to_cpu(bmp[(sec & 0x3fff) >> 5]) >> (sec & 0x1f) & 1)) {
333		hpfs_error(s, "sector %08x not allocated", sec);
334		hpfs_brelse4(&qbh);
335		return;
336	}
337	bmp[(sec & 0x3fff) >> 5] |= cpu_to_le32(1 << (sec & 0x1f));
338	hpfs_claim_free(s, sec);
339	if (!--n) {
340		hpfs_mark_4buffers_dirty(&qbh);
341		hpfs_brelse4(&qbh);
342		return;
343	}
344	if (!(++sec & 0x3fff)) {
345		hpfs_mark_4buffers_dirty(&qbh);
346		hpfs_brelse4(&qbh);
347		goto new_map;
348	}
349	goto new_tst;
350}
351
352/*
353 * Check if there are at least n free dnodes on the filesystem.
354 * Called before adding to dnode. If we run out of space while
355 * splitting dnodes, it would corrupt dnode tree.
356 */
357
358int hpfs_check_free_dnodes(struct super_block *s, int n)
359{
360	int n_bmps = (hpfs_sb(s)->sb_fs_size + 0x4000 - 1) >> 14;
361	int b = hpfs_sb(s)->sb_c_bitmap & 0x0fffffff;
362	int i, j;
363	__le32 *bmp;
364	struct quad_buffer_head qbh;
365	if ((bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
366		for (j = 0; j < 512; j++) {
367			unsigned k;
368			if (!le32_to_cpu(bmp[j])) continue;
369			for (k = le32_to_cpu(bmp[j]); k; k >>= 1) if (k & 1) if (!--n) {
370				hpfs_brelse4(&qbh);
371				return 0;
372			}
373		}
374	}
375	hpfs_brelse4(&qbh);
376	i = 0;
377	if (hpfs_sb(s)->sb_c_bitmap != -1) {
378		bmp = hpfs_map_bitmap(s, b, &qbh, "chkdn1");
379		goto chk_bmp;
380	}
381	chk_next:
382	if (i == b) i++;
383	if (i >= n_bmps) return 1;
384	bmp = hpfs_map_bitmap(s, i, &qbh, "chkdn2");
385	chk_bmp:
386	if (bmp) {
387		for (j = 0; j < 512; j++) {
388			u32 k;
389			if (!le32_to_cpu(bmp[j])) continue;
390			for (k = 0xf; k; k <<= 4)
391				if ((le32_to_cpu(bmp[j]) & k) == k) {
392					if (!--n) {
393						hpfs_brelse4(&qbh);
394						return 0;
395					}
396				}
397		}
398		hpfs_brelse4(&qbh);
399	}
400	i++;
401	goto chk_next;
402}
403
404void hpfs_free_dnode(struct super_block *s, dnode_secno dno)
405{
406	if (hpfs_sb(s)->sb_chk) if (dno & 3) {
407		hpfs_error(s, "hpfs_free_dnode: dnode %08x not aligned", dno);
408		return;
409	}
410	if (dno < hpfs_sb(s)->sb_dirband_start ||
411	    dno >= hpfs_sb(s)->sb_dirband_start + hpfs_sb(s)->sb_dirband_size) {
412		hpfs_free_sectors(s, dno, 4);
413	} else {
414		struct quad_buffer_head qbh;
415		__le32 *bmp;
416		unsigned ssec = (dno - hpfs_sb(s)->sb_dirband_start) / 4;
417		if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
418			return;
419		}
420		bmp[ssec >> 5] |= cpu_to_le32(1 << (ssec & 0x1f));
421		hpfs_mark_4buffers_dirty(&qbh);
422		hpfs_brelse4(&qbh);
423		hpfs_claim_dirband_free(s, dno);
424	}
425}
426
427struct dnode *hpfs_alloc_dnode(struct super_block *s, secno near,
428			 dnode_secno *dno, struct quad_buffer_head *qbh)
429{
430	struct dnode *d;
431	if (hpfs_get_free_dnodes(s) > FREE_DNODES_ADD) {
432		if (!(*dno = alloc_in_dirband(s, near)))
433			if (!(*dno = hpfs_alloc_sector(s, near, 4, 0))) return NULL;
434	} else {
435		if (!(*dno = hpfs_alloc_sector(s, near, 4, 0)))
436			if (!(*dno = alloc_in_dirband(s, near))) return NULL;
437	}
438	if (!(d = hpfs_get_4sectors(s, *dno, qbh))) {
439		hpfs_free_dnode(s, *dno);
440		return NULL;
441	}
442	memset(d, 0, 2048);
443	d->magic = cpu_to_le32(DNODE_MAGIC);
444	d->first_free = cpu_to_le32(52);
445	d->dirent[0] = 32;
446	d->dirent[2] = 8;
447	d->dirent[30] = 1;
448	d->dirent[31] = 255;
449	d->self = cpu_to_le32(*dno);
450	return d;
451}
452
453struct fnode *hpfs_alloc_fnode(struct super_block *s, secno near, fnode_secno *fno,
454			  struct buffer_head **bh)
455{
456	struct fnode *f;
457	if (!(*fno = hpfs_alloc_sector(s, near, 1, FNODE_ALLOC_FWD))) return NULL;
458	if (!(f = hpfs_get_sector(s, *fno, bh))) {
459		hpfs_free_sectors(s, *fno, 1);
460		return NULL;
461	}
462	memset(f, 0, 512);
463	f->magic = cpu_to_le32(FNODE_MAGIC);
464	f->ea_offs = cpu_to_le16(0xc4);
465	f->btree.n_free_nodes = 8;
466	f->btree.first_free = cpu_to_le16(8);
467	return f;
468}
469
470struct anode *hpfs_alloc_anode(struct super_block *s, secno near, anode_secno *ano,
471			  struct buffer_head **bh)
472{
473	struct anode *a;
474	if (!(*ano = hpfs_alloc_sector(s, near, 1, ANODE_ALLOC_FWD))) return NULL;
475	if (!(a = hpfs_get_sector(s, *ano, bh))) {
476		hpfs_free_sectors(s, *ano, 1);
477		return NULL;
478	}
479	memset(a, 0, 512);
480	a->magic = cpu_to_le32(ANODE_MAGIC);
481	a->self = cpu_to_le32(*ano);
482	a->btree.n_free_nodes = 40;
483	a->btree.n_used_nodes = 0;
484	a->btree.first_free = cpu_to_le16(8);
485	return a;
486}
487
488static unsigned find_run(__le32 *bmp, unsigned *idx)
489{
490	unsigned len;
491	while (tstbits(bmp, *idx, 1)) {
492		(*idx)++;
493		if (unlikely(*idx >= 0x4000))
494			return 0;
495	}
496	len = 1;
497	while (!tstbits(bmp, *idx + len, 1))
498		len++;
499	return len;
500}
501
502static int do_trim(struct super_block *s, secno start, unsigned len, secno limit_start, secno limit_end, unsigned minlen, unsigned *result)
503{
504	int err;
505	secno end;
506	if (fatal_signal_pending(current))
507		return -EINTR;
508	end = start + len;
509	if (start < limit_start)
510		start = limit_start;
511	if (end > limit_end)
512		end = limit_end;
513	if (start >= end)
514		return 0;
515	if (end - start < minlen)
516		return 0;
517	err = sb_issue_discard(s, start, end - start, GFP_NOFS, 0);
518	if (err)
519		return err;
520	*result += end - start;
521	return 0;
522}
523
524int hpfs_trim_fs(struct super_block *s, u64 start, u64 end, u64 minlen, unsigned *result)
525{
526	int err = 0;
527	struct hpfs_sb_info *sbi = hpfs_sb(s);
528	unsigned idx, len, start_bmp, end_bmp;
529	__le32 *bmp;
530	struct quad_buffer_head qbh;
531
532	*result = 0;
533	if (!end || end > sbi->sb_fs_size)
534		end = sbi->sb_fs_size;
535	if (start >= sbi->sb_fs_size)
536		return 0;
537	if (minlen > 0x4000)
538		return 0;
539	if (start < sbi->sb_dirband_start + sbi->sb_dirband_size && end > sbi->sb_dirband_start) {
540		hpfs_lock(s);
541		if (s->s_flags & MS_RDONLY) {
542			err = -EROFS;
543			goto unlock_1;
544		}
545		if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
546			err = -EIO;
547			goto unlock_1;
548		}
549		idx = 0;
550		while ((len = find_run(bmp, &idx)) && !err) {
551			err = do_trim(s, sbi->sb_dirband_start + idx * 4, len * 4, start, end, minlen, result);
552			idx += len;
553		}
554		hpfs_brelse4(&qbh);
555unlock_1:
556		hpfs_unlock(s);
557	}
558	start_bmp = start >> 14;
559	end_bmp = (end + 0x3fff) >> 14;
560	while (start_bmp < end_bmp && !err) {
561		hpfs_lock(s);
562		if (s->s_flags & MS_RDONLY) {
563			err = -EROFS;
564			goto unlock_2;
565		}
566		if (!(bmp = hpfs_map_bitmap(s, start_bmp, &qbh, "trim"))) {
567			err = -EIO;
568			goto unlock_2;
569		}
570		idx = 0;
571		while ((len = find_run(bmp, &idx)) && !err) {
572			err = do_trim(s, (start_bmp << 14) + idx, len, start, end, minlen, result);
573			idx += len;
574		}
575		hpfs_brelse4(&qbh);
576unlock_2:
577		hpfs_unlock(s);
578		start_bmp++;
579	}
580	return err;
581}
582