xref: /linux/fs/ufs/balloc.c (revision 60e13231561b3a4c5269bfa1ef6c0569ad6f28ec)
1 /*
2  *  linux/fs/ufs/balloc.c
3  *
4  * Copyright (C) 1998
5  * Daniel Pirkl <daniel.pirkl@email.cz>
6  * Charles University, Faculty of Mathematics and Physics
7  *
8  * UFS2 write support Evgeniy Dushistov <dushistov@mail.ru>, 2007
9  */
10 
11 #include <linux/fs.h>
12 #include <linux/stat.h>
13 #include <linux/time.h>
14 #include <linux/string.h>
15 #include <linux/buffer_head.h>
16 #include <linux/capability.h>
17 #include <linux/bitops.h>
18 #include <asm/byteorder.h>
19 
20 #include "ufs_fs.h"
21 #include "ufs.h"
22 #include "swab.h"
23 #include "util.h"
24 
25 #define INVBLOCK ((u64)-1L)
26 
27 static u64 ufs_add_fragments(struct inode *, u64, unsigned, unsigned, int *);
28 static u64 ufs_alloc_fragments(struct inode *, unsigned, u64, unsigned, int *);
29 static u64 ufs_alloccg_block(struct inode *, struct ufs_cg_private_info *, u64, int *);
30 static u64 ufs_bitmap_search (struct super_block *, struct ufs_cg_private_info *, u64, unsigned);
31 static unsigned char ufs_fragtable_8fpb[], ufs_fragtable_other[];
32 static void ufs_clusteracct(struct super_block *, struct ufs_cg_private_info *, unsigned, int);
33 
34 /*
35  * Free 'count' fragments from fragment number 'fragment'
36  */
37 void ufs_free_fragments(struct inode *inode, u64 fragment, unsigned count)
38 {
39 	struct super_block * sb;
40 	struct ufs_sb_private_info * uspi;
41 	struct ufs_super_block_first * usb1;
42 	struct ufs_cg_private_info * ucpi;
43 	struct ufs_cylinder_group * ucg;
44 	unsigned cgno, bit, end_bit, bbase, blkmap, i;
45 	u64 blkno;
46 
47 	sb = inode->i_sb;
48 	uspi = UFS_SB(sb)->s_uspi;
49 	usb1 = ubh_get_usb_first(uspi);
50 
51 	UFSD("ENTER, fragment %llu, count %u\n",
52 	     (unsigned long long)fragment, count);
53 
54 	if (ufs_fragnum(fragment) + count > uspi->s_fpg)
55 		ufs_error (sb, "ufs_free_fragments", "internal error");
56 
57 	lock_super(sb);
58 
59 	cgno = ufs_dtog(uspi, fragment);
60 	bit = ufs_dtogd(uspi, fragment);
61 	if (cgno >= uspi->s_ncg) {
62 		ufs_panic (sb, "ufs_free_fragments", "freeing blocks are outside device");
63 		goto failed;
64 	}
65 
66 	ucpi = ufs_load_cylinder (sb, cgno);
67 	if (!ucpi)
68 		goto failed;
69 	ucg = ubh_get_ucg (UCPI_UBH(ucpi));
70 	if (!ufs_cg_chkmagic(sb, ucg)) {
71 		ufs_panic (sb, "ufs_free_fragments", "internal error, bad magic number on cg %u", cgno);
72 		goto failed;
73 	}
74 
75 	end_bit = bit + count;
76 	bbase = ufs_blknum (bit);
77 	blkmap = ubh_blkmap (UCPI_UBH(ucpi), ucpi->c_freeoff, bbase);
78 	ufs_fragacct (sb, blkmap, ucg->cg_frsum, -1);
79 	for (i = bit; i < end_bit; i++) {
80 		if (ubh_isclr (UCPI_UBH(ucpi), ucpi->c_freeoff, i))
81 			ubh_setbit (UCPI_UBH(ucpi), ucpi->c_freeoff, i);
82 		else
83 			ufs_error (sb, "ufs_free_fragments",
84 				   "bit already cleared for fragment %u", i);
85 	}
86 
87 	fs32_add(sb, &ucg->cg_cs.cs_nffree, count);
88 	uspi->cs_total.cs_nffree += count;
89 	fs32_add(sb, &UFS_SB(sb)->fs_cs(cgno).cs_nffree, count);
90 	blkmap = ubh_blkmap (UCPI_UBH(ucpi), ucpi->c_freeoff, bbase);
91 	ufs_fragacct(sb, blkmap, ucg->cg_frsum, 1);
92 
93 	/*
94 	 * Trying to reassemble free fragments into block
95 	 */
96 	blkno = ufs_fragstoblks (bbase);
97 	if (ubh_isblockset(UCPI_UBH(ucpi), ucpi->c_freeoff, blkno)) {
98 		fs32_sub(sb, &ucg->cg_cs.cs_nffree, uspi->s_fpb);
99 		uspi->cs_total.cs_nffree -= uspi->s_fpb;
100 		fs32_sub(sb, &UFS_SB(sb)->fs_cs(cgno).cs_nffree, uspi->s_fpb);
101 		if ((UFS_SB(sb)->s_flags & UFS_CG_MASK) == UFS_CG_44BSD)
102 			ufs_clusteracct (sb, ucpi, blkno, 1);
103 		fs32_add(sb, &ucg->cg_cs.cs_nbfree, 1);
104 		uspi->cs_total.cs_nbfree++;
105 		fs32_add(sb, &UFS_SB(sb)->fs_cs(cgno).cs_nbfree, 1);
106 		if (uspi->fs_magic != UFS2_MAGIC) {
107 			unsigned cylno = ufs_cbtocylno (bbase);
108 
109 			fs16_add(sb, &ubh_cg_blks(ucpi, cylno,
110 						  ufs_cbtorpos(bbase)), 1);
111 			fs32_add(sb, &ubh_cg_blktot(ucpi, cylno), 1);
112 		}
113 	}
114 
115 	ubh_mark_buffer_dirty (USPI_UBH(uspi));
116 	ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
117 	if (sb->s_flags & MS_SYNCHRONOUS)
118 		ubh_sync_block(UCPI_UBH(ucpi));
119 	sb->s_dirt = 1;
120 
121 	unlock_super (sb);
122 	UFSD("EXIT\n");
123 	return;
124 
125 failed:
126 	unlock_super (sb);
127 	UFSD("EXIT (FAILED)\n");
128 	return;
129 }
130 
131 /*
132  * Free 'count' fragments from fragment number 'fragment' (free whole blocks)
133  */
134 void ufs_free_blocks(struct inode *inode, u64 fragment, unsigned count)
135 {
136 	struct super_block * sb;
137 	struct ufs_sb_private_info * uspi;
138 	struct ufs_super_block_first * usb1;
139 	struct ufs_cg_private_info * ucpi;
140 	struct ufs_cylinder_group * ucg;
141 	unsigned overflow, cgno, bit, end_bit, i;
142 	u64 blkno;
143 
144 	sb = inode->i_sb;
145 	uspi = UFS_SB(sb)->s_uspi;
146 	usb1 = ubh_get_usb_first(uspi);
147 
148 	UFSD("ENTER, fragment %llu, count %u\n",
149 	     (unsigned long long)fragment, count);
150 
151 	if ((fragment & uspi->s_fpbmask) || (count & uspi->s_fpbmask)) {
152 		ufs_error (sb, "ufs_free_blocks", "internal error, "
153 			   "fragment %llu, count %u\n",
154 			   (unsigned long long)fragment, count);
155 		goto failed;
156 	}
157 
158 	lock_super(sb);
159 
160 do_more:
161 	overflow = 0;
162 	cgno = ufs_dtog(uspi, fragment);
163 	bit = ufs_dtogd(uspi, fragment);
164 	if (cgno >= uspi->s_ncg) {
165 		ufs_panic (sb, "ufs_free_blocks", "freeing blocks are outside device");
166 		goto failed_unlock;
167 	}
168 	end_bit = bit + count;
169 	if (end_bit > uspi->s_fpg) {
170 		overflow = bit + count - uspi->s_fpg;
171 		count -= overflow;
172 		end_bit -= overflow;
173 	}
174 
175 	ucpi = ufs_load_cylinder (sb, cgno);
176 	if (!ucpi)
177 		goto failed_unlock;
178 	ucg = ubh_get_ucg (UCPI_UBH(ucpi));
179 	if (!ufs_cg_chkmagic(sb, ucg)) {
180 		ufs_panic (sb, "ufs_free_blocks", "internal error, bad magic number on cg %u", cgno);
181 		goto failed_unlock;
182 	}
183 
184 	for (i = bit; i < end_bit; i += uspi->s_fpb) {
185 		blkno = ufs_fragstoblks(i);
186 		if (ubh_isblockset(UCPI_UBH(ucpi), ucpi->c_freeoff, blkno)) {
187 			ufs_error(sb, "ufs_free_blocks", "freeing free fragment");
188 		}
189 		ubh_setblock(UCPI_UBH(ucpi), ucpi->c_freeoff, blkno);
190 		if ((UFS_SB(sb)->s_flags & UFS_CG_MASK) == UFS_CG_44BSD)
191 			ufs_clusteracct (sb, ucpi, blkno, 1);
192 
193 		fs32_add(sb, &ucg->cg_cs.cs_nbfree, 1);
194 		uspi->cs_total.cs_nbfree++;
195 		fs32_add(sb, &UFS_SB(sb)->fs_cs(cgno).cs_nbfree, 1);
196 
197 		if (uspi->fs_magic != UFS2_MAGIC) {
198 			unsigned cylno = ufs_cbtocylno(i);
199 
200 			fs16_add(sb, &ubh_cg_blks(ucpi, cylno,
201 						  ufs_cbtorpos(i)), 1);
202 			fs32_add(sb, &ubh_cg_blktot(ucpi, cylno), 1);
203 		}
204 	}
205 
206 	ubh_mark_buffer_dirty (USPI_UBH(uspi));
207 	ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
208 	if (sb->s_flags & MS_SYNCHRONOUS)
209 		ubh_sync_block(UCPI_UBH(ucpi));
210 
211 	if (overflow) {
212 		fragment += count;
213 		count = overflow;
214 		goto do_more;
215 	}
216 
217 	sb->s_dirt = 1;
218 	unlock_super (sb);
219 	UFSD("EXIT\n");
220 	return;
221 
222 failed_unlock:
223 	unlock_super (sb);
224 failed:
225 	UFSD("EXIT (FAILED)\n");
226 	return;
227 }
228 
229 /*
230  * Modify inode page cache in such way:
231  * have - blocks with b_blocknr equal to oldb...oldb+count-1
232  * get - blocks with b_blocknr equal to newb...newb+count-1
233  * also we suppose that oldb...oldb+count-1 blocks
234  * situated at the end of file.
235  *
236  * We can come here from ufs_writepage or ufs_prepare_write,
237  * locked_page is argument of these functions, so we already lock it.
238  */
239 static void ufs_change_blocknr(struct inode *inode, sector_t beg,
240 			       unsigned int count, sector_t oldb,
241 			       sector_t newb, struct page *locked_page)
242 {
243 	const unsigned blks_per_page =
244 		1 << (PAGE_CACHE_SHIFT - inode->i_blkbits);
245 	const unsigned mask = blks_per_page - 1;
246 	struct address_space * const mapping = inode->i_mapping;
247 	pgoff_t index, cur_index, last_index;
248 	unsigned pos, j, lblock;
249 	sector_t end, i;
250 	struct page *page;
251 	struct buffer_head *head, *bh;
252 
253 	UFSD("ENTER, ino %lu, count %u, oldb %llu, newb %llu\n",
254 	      inode->i_ino, count,
255 	     (unsigned long long)oldb, (unsigned long long)newb);
256 
257 	BUG_ON(!locked_page);
258 	BUG_ON(!PageLocked(locked_page));
259 
260 	cur_index = locked_page->index;
261 	end = count + beg;
262 	last_index = end >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
263 	for (i = beg; i < end; i = (i | mask) + 1) {
264 		index = i >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
265 
266 		if (likely(cur_index != index)) {
267 			page = ufs_get_locked_page(mapping, index);
268 			if (!page)/* it was truncated */
269 				continue;
270 			if (IS_ERR(page)) {/* or EIO */
271 				ufs_error(inode->i_sb, __func__,
272 					  "read of page %llu failed\n",
273 					  (unsigned long long)index);
274 				continue;
275 			}
276 		} else
277 			page = locked_page;
278 
279 		head = page_buffers(page);
280 		bh = head;
281 		pos = i & mask;
282 		for (j = 0; j < pos; ++j)
283 			bh = bh->b_this_page;
284 
285 
286 		if (unlikely(index == last_index))
287 			lblock = end & mask;
288 		else
289 			lblock = blks_per_page;
290 
291 		do {
292 			if (j >= lblock)
293 				break;
294 			pos = (i - beg) + j;
295 
296 			if (!buffer_mapped(bh))
297 					map_bh(bh, inode->i_sb, oldb + pos);
298 			if (!buffer_uptodate(bh)) {
299 				ll_rw_block(READ, 1, &bh);
300 				wait_on_buffer(bh);
301 				if (!buffer_uptodate(bh)) {
302 					ufs_error(inode->i_sb, __func__,
303 						  "read of block failed\n");
304 					break;
305 				}
306 			}
307 
308 			UFSD(" change from %llu to %llu, pos %u\n",
309 			     (unsigned long long)(pos + oldb),
310 			     (unsigned long long)(pos + newb), pos);
311 
312 			bh->b_blocknr = newb + pos;
313 			unmap_underlying_metadata(bh->b_bdev,
314 						  bh->b_blocknr);
315 			mark_buffer_dirty(bh);
316 			++j;
317 			bh = bh->b_this_page;
318 		} while (bh != head);
319 
320 		if (likely(cur_index != index))
321 			ufs_put_locked_page(page);
322  	}
323 	UFSD("EXIT\n");
324 }
325 
326 static void ufs_clear_frags(struct inode *inode, sector_t beg, unsigned int n,
327 			    int sync)
328 {
329 	struct buffer_head *bh;
330 	sector_t end = beg + n;
331 
332 	for (; beg < end; ++beg) {
333 		bh = sb_getblk(inode->i_sb, beg);
334 		lock_buffer(bh);
335 		memset(bh->b_data, 0, inode->i_sb->s_blocksize);
336 		set_buffer_uptodate(bh);
337 		mark_buffer_dirty(bh);
338 		unlock_buffer(bh);
339 		if (IS_SYNC(inode) || sync)
340 			sync_dirty_buffer(bh);
341 		brelse(bh);
342 	}
343 }
344 
345 u64 ufs_new_fragments(struct inode *inode, void *p, u64 fragment,
346 			   u64 goal, unsigned count, int *err,
347 			   struct page *locked_page)
348 {
349 	struct super_block * sb;
350 	struct ufs_sb_private_info * uspi;
351 	struct ufs_super_block_first * usb1;
352 	unsigned cgno, oldcount, newcount;
353 	u64 tmp, request, result;
354 
355 	UFSD("ENTER, ino %lu, fragment %llu, goal %llu, count %u\n",
356 	     inode->i_ino, (unsigned long long)fragment,
357 	     (unsigned long long)goal, count);
358 
359 	sb = inode->i_sb;
360 	uspi = UFS_SB(sb)->s_uspi;
361 	usb1 = ubh_get_usb_first(uspi);
362 	*err = -ENOSPC;
363 
364 	lock_super (sb);
365 	tmp = ufs_data_ptr_to_cpu(sb, p);
366 
367 	if (count + ufs_fragnum(fragment) > uspi->s_fpb) {
368 		ufs_warning(sb, "ufs_new_fragments", "internal warning"
369 			    " fragment %llu, count %u",
370 			    (unsigned long long)fragment, count);
371 		count = uspi->s_fpb - ufs_fragnum(fragment);
372 	}
373 	oldcount = ufs_fragnum (fragment);
374 	newcount = oldcount + count;
375 
376 	/*
377 	 * Somebody else has just allocated our fragments
378 	 */
379 	if (oldcount) {
380 		if (!tmp) {
381 			ufs_error(sb, "ufs_new_fragments", "internal error, "
382 				  "fragment %llu, tmp %llu\n",
383 				  (unsigned long long)fragment,
384 				  (unsigned long long)tmp);
385 			unlock_super(sb);
386 			return INVBLOCK;
387 		}
388 		if (fragment < UFS_I(inode)->i_lastfrag) {
389 			UFSD("EXIT (ALREADY ALLOCATED)\n");
390 			unlock_super (sb);
391 			return 0;
392 		}
393 	}
394 	else {
395 		if (tmp) {
396 			UFSD("EXIT (ALREADY ALLOCATED)\n");
397 			unlock_super(sb);
398 			return 0;
399 		}
400 	}
401 
402 	/*
403 	 * There is not enough space for user on the device
404 	 */
405 	if (!capable(CAP_SYS_RESOURCE) && ufs_freespace(uspi, UFS_MINFREE) <= 0) {
406 		unlock_super (sb);
407 		UFSD("EXIT (FAILED)\n");
408 		return 0;
409 	}
410 
411 	if (goal >= uspi->s_size)
412 		goal = 0;
413 	if (goal == 0)
414 		cgno = ufs_inotocg (inode->i_ino);
415 	else
416 		cgno = ufs_dtog(uspi, goal);
417 
418 	/*
419 	 * allocate new fragment
420 	 */
421 	if (oldcount == 0) {
422 		result = ufs_alloc_fragments (inode, cgno, goal, count, err);
423 		if (result) {
424 			ufs_cpu_to_data_ptr(sb, p, result);
425 			*err = 0;
426 			UFS_I(inode)->i_lastfrag =
427 				max(UFS_I(inode)->i_lastfrag, fragment + count);
428 			ufs_clear_frags(inode, result + oldcount,
429 					newcount - oldcount, locked_page != NULL);
430 		}
431 		unlock_super(sb);
432 		UFSD("EXIT, result %llu\n", (unsigned long long)result);
433 		return result;
434 	}
435 
436 	/*
437 	 * resize block
438 	 */
439 	result = ufs_add_fragments (inode, tmp, oldcount, newcount, err);
440 	if (result) {
441 		*err = 0;
442 		UFS_I(inode)->i_lastfrag = max(UFS_I(inode)->i_lastfrag,
443 						fragment + count);
444 		ufs_clear_frags(inode, result + oldcount, newcount - oldcount,
445 				locked_page != NULL);
446 		unlock_super(sb);
447 		UFSD("EXIT, result %llu\n", (unsigned long long)result);
448 		return result;
449 	}
450 
451 	/*
452 	 * allocate new block and move data
453 	 */
454 	switch (fs32_to_cpu(sb, usb1->fs_optim)) {
455 	    case UFS_OPTSPACE:
456 		request = newcount;
457 		if (uspi->s_minfree < 5 || uspi->cs_total.cs_nffree
458 		    > uspi->s_dsize * uspi->s_minfree / (2 * 100))
459 			break;
460 		usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME);
461 		break;
462 	    default:
463 		usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME);
464 
465 	    case UFS_OPTTIME:
466 		request = uspi->s_fpb;
467 		if (uspi->cs_total.cs_nffree < uspi->s_dsize *
468 		    (uspi->s_minfree - 2) / 100)
469 			break;
470 		usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME);
471 		break;
472 	}
473 	result = ufs_alloc_fragments (inode, cgno, goal, request, err);
474 	if (result) {
475 		ufs_clear_frags(inode, result + oldcount, newcount - oldcount,
476 				locked_page != NULL);
477 		ufs_change_blocknr(inode, fragment - oldcount, oldcount,
478 				   uspi->s_sbbase + tmp,
479 				   uspi->s_sbbase + result, locked_page);
480 		ufs_cpu_to_data_ptr(sb, p, result);
481 		*err = 0;
482 		UFS_I(inode)->i_lastfrag = max(UFS_I(inode)->i_lastfrag,
483 						fragment + count);
484 		unlock_super(sb);
485 		if (newcount < request)
486 			ufs_free_fragments (inode, result + newcount, request - newcount);
487 		ufs_free_fragments (inode, tmp, oldcount);
488 		UFSD("EXIT, result %llu\n", (unsigned long long)result);
489 		return result;
490 	}
491 
492 	unlock_super(sb);
493 	UFSD("EXIT (FAILED)\n");
494 	return 0;
495 }
496 
497 static u64 ufs_add_fragments(struct inode *inode, u64 fragment,
498 			     unsigned oldcount, unsigned newcount, int *err)
499 {
500 	struct super_block * sb;
501 	struct ufs_sb_private_info * uspi;
502 	struct ufs_super_block_first * usb1;
503 	struct ufs_cg_private_info * ucpi;
504 	struct ufs_cylinder_group * ucg;
505 	unsigned cgno, fragno, fragoff, count, fragsize, i;
506 
507 	UFSD("ENTER, fragment %llu, oldcount %u, newcount %u\n",
508 	     (unsigned long long)fragment, oldcount, newcount);
509 
510 	sb = inode->i_sb;
511 	uspi = UFS_SB(sb)->s_uspi;
512 	usb1 = ubh_get_usb_first (uspi);
513 	count = newcount - oldcount;
514 
515 	cgno = ufs_dtog(uspi, fragment);
516 	if (fs32_to_cpu(sb, UFS_SB(sb)->fs_cs(cgno).cs_nffree) < count)
517 		return 0;
518 	if ((ufs_fragnum (fragment) + newcount) > uspi->s_fpb)
519 		return 0;
520 	ucpi = ufs_load_cylinder (sb, cgno);
521 	if (!ucpi)
522 		return 0;
523 	ucg = ubh_get_ucg (UCPI_UBH(ucpi));
524 	if (!ufs_cg_chkmagic(sb, ucg)) {
525 		ufs_panic (sb, "ufs_add_fragments",
526 			"internal error, bad magic number on cg %u", cgno);
527 		return 0;
528 	}
529 
530 	fragno = ufs_dtogd(uspi, fragment);
531 	fragoff = ufs_fragnum (fragno);
532 	for (i = oldcount; i < newcount; i++)
533 		if (ubh_isclr (UCPI_UBH(ucpi), ucpi->c_freeoff, fragno + i))
534 			return 0;
535 	/*
536 	 * Block can be extended
537 	 */
538 	ucg->cg_time = cpu_to_fs32(sb, get_seconds());
539 	for (i = newcount; i < (uspi->s_fpb - fragoff); i++)
540 		if (ubh_isclr (UCPI_UBH(ucpi), ucpi->c_freeoff, fragno + i))
541 			break;
542 	fragsize = i - oldcount;
543 	if (!fs32_to_cpu(sb, ucg->cg_frsum[fragsize]))
544 		ufs_panic (sb, "ufs_add_fragments",
545 			"internal error or corrupted bitmap on cg %u", cgno);
546 	fs32_sub(sb, &ucg->cg_frsum[fragsize], 1);
547 	if (fragsize != count)
548 		fs32_add(sb, &ucg->cg_frsum[fragsize - count], 1);
549 	for (i = oldcount; i < newcount; i++)
550 		ubh_clrbit (UCPI_UBH(ucpi), ucpi->c_freeoff, fragno + i);
551 
552 	fs32_sub(sb, &ucg->cg_cs.cs_nffree, count);
553 	fs32_sub(sb, &UFS_SB(sb)->fs_cs(cgno).cs_nffree, count);
554 	uspi->cs_total.cs_nffree -= count;
555 
556 	ubh_mark_buffer_dirty (USPI_UBH(uspi));
557 	ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
558 	if (sb->s_flags & MS_SYNCHRONOUS)
559 		ubh_sync_block(UCPI_UBH(ucpi));
560 	sb->s_dirt = 1;
561 
562 	UFSD("EXIT, fragment %llu\n", (unsigned long long)fragment);
563 
564 	return fragment;
565 }
566 
567 #define UFS_TEST_FREE_SPACE_CG \
568 	ucg = (struct ufs_cylinder_group *) UFS_SB(sb)->s_ucg[cgno]->b_data; \
569 	if (fs32_to_cpu(sb, ucg->cg_cs.cs_nbfree)) \
570 		goto cg_found; \
571 	for (k = count; k < uspi->s_fpb; k++) \
572 		if (fs32_to_cpu(sb, ucg->cg_frsum[k])) \
573 			goto cg_found;
574 
575 static u64 ufs_alloc_fragments(struct inode *inode, unsigned cgno,
576 			       u64 goal, unsigned count, int *err)
577 {
578 	struct super_block * sb;
579 	struct ufs_sb_private_info * uspi;
580 	struct ufs_super_block_first * usb1;
581 	struct ufs_cg_private_info * ucpi;
582 	struct ufs_cylinder_group * ucg;
583 	unsigned oldcg, i, j, k, allocsize;
584 	u64 result;
585 
586 	UFSD("ENTER, ino %lu, cgno %u, goal %llu, count %u\n",
587 	     inode->i_ino, cgno, (unsigned long long)goal, count);
588 
589 	sb = inode->i_sb;
590 	uspi = UFS_SB(sb)->s_uspi;
591 	usb1 = ubh_get_usb_first(uspi);
592 	oldcg = cgno;
593 
594 	/*
595 	 * 1. searching on preferred cylinder group
596 	 */
597 	UFS_TEST_FREE_SPACE_CG
598 
599 	/*
600 	 * 2. quadratic rehash
601 	 */
602 	for (j = 1; j < uspi->s_ncg; j *= 2) {
603 		cgno += j;
604 		if (cgno >= uspi->s_ncg)
605 			cgno -= uspi->s_ncg;
606 		UFS_TEST_FREE_SPACE_CG
607 	}
608 
609 	/*
610 	 * 3. brute force search
611 	 * We start at i = 2 ( 0 is checked at 1.step, 1 at 2.step )
612 	 */
613 	cgno = (oldcg + 1) % uspi->s_ncg;
614 	for (j = 2; j < uspi->s_ncg; j++) {
615 		cgno++;
616 		if (cgno >= uspi->s_ncg)
617 			cgno = 0;
618 		UFS_TEST_FREE_SPACE_CG
619 	}
620 
621 	UFSD("EXIT (FAILED)\n");
622 	return 0;
623 
624 cg_found:
625 	ucpi = ufs_load_cylinder (sb, cgno);
626 	if (!ucpi)
627 		return 0;
628 	ucg = ubh_get_ucg (UCPI_UBH(ucpi));
629 	if (!ufs_cg_chkmagic(sb, ucg))
630 		ufs_panic (sb, "ufs_alloc_fragments",
631 			"internal error, bad magic number on cg %u", cgno);
632 	ucg->cg_time = cpu_to_fs32(sb, get_seconds());
633 
634 	if (count == uspi->s_fpb) {
635 		result = ufs_alloccg_block (inode, ucpi, goal, err);
636 		if (result == INVBLOCK)
637 			return 0;
638 		goto succed;
639 	}
640 
641 	for (allocsize = count; allocsize < uspi->s_fpb; allocsize++)
642 		if (fs32_to_cpu(sb, ucg->cg_frsum[allocsize]) != 0)
643 			break;
644 
645 	if (allocsize == uspi->s_fpb) {
646 		result = ufs_alloccg_block (inode, ucpi, goal, err);
647 		if (result == INVBLOCK)
648 			return 0;
649 		goal = ufs_dtogd(uspi, result);
650 		for (i = count; i < uspi->s_fpb; i++)
651 			ubh_setbit (UCPI_UBH(ucpi), ucpi->c_freeoff, goal + i);
652 		i = uspi->s_fpb - count;
653 
654 		fs32_add(sb, &ucg->cg_cs.cs_nffree, i);
655 		uspi->cs_total.cs_nffree += i;
656 		fs32_add(sb, &UFS_SB(sb)->fs_cs(cgno).cs_nffree, i);
657 		fs32_add(sb, &ucg->cg_frsum[i], 1);
658 		goto succed;
659 	}
660 
661 	result = ufs_bitmap_search (sb, ucpi, goal, allocsize);
662 	if (result == INVBLOCK)
663 		return 0;
664 	for (i = 0; i < count; i++)
665 		ubh_clrbit (UCPI_UBH(ucpi), ucpi->c_freeoff, result + i);
666 
667 	fs32_sub(sb, &ucg->cg_cs.cs_nffree, count);
668 	uspi->cs_total.cs_nffree -= count;
669 	fs32_sub(sb, &UFS_SB(sb)->fs_cs(cgno).cs_nffree, count);
670 	fs32_sub(sb, &ucg->cg_frsum[allocsize], 1);
671 
672 	if (count != allocsize)
673 		fs32_add(sb, &ucg->cg_frsum[allocsize - count], 1);
674 
675 succed:
676 	ubh_mark_buffer_dirty (USPI_UBH(uspi));
677 	ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
678 	if (sb->s_flags & MS_SYNCHRONOUS)
679 		ubh_sync_block(UCPI_UBH(ucpi));
680 	sb->s_dirt = 1;
681 
682 	result += cgno * uspi->s_fpg;
683 	UFSD("EXIT3, result %llu\n", (unsigned long long)result);
684 	return result;
685 }
686 
687 static u64 ufs_alloccg_block(struct inode *inode,
688 			     struct ufs_cg_private_info *ucpi,
689 			     u64 goal, int *err)
690 {
691 	struct super_block * sb;
692 	struct ufs_sb_private_info * uspi;
693 	struct ufs_super_block_first * usb1;
694 	struct ufs_cylinder_group * ucg;
695 	u64 result, blkno;
696 
697 	UFSD("ENTER, goal %llu\n", (unsigned long long)goal);
698 
699 	sb = inode->i_sb;
700 	uspi = UFS_SB(sb)->s_uspi;
701 	usb1 = ubh_get_usb_first(uspi);
702 	ucg = ubh_get_ucg(UCPI_UBH(ucpi));
703 
704 	if (goal == 0) {
705 		goal = ucpi->c_rotor;
706 		goto norot;
707 	}
708 	goal = ufs_blknum (goal);
709 	goal = ufs_dtogd(uspi, goal);
710 
711 	/*
712 	 * If the requested block is available, use it.
713 	 */
714 	if (ubh_isblockset(UCPI_UBH(ucpi), ucpi->c_freeoff, ufs_fragstoblks(goal))) {
715 		result = goal;
716 		goto gotit;
717 	}
718 
719 norot:
720 	result = ufs_bitmap_search (sb, ucpi, goal, uspi->s_fpb);
721 	if (result == INVBLOCK)
722 		return INVBLOCK;
723 	ucpi->c_rotor = result;
724 gotit:
725 	blkno = ufs_fragstoblks(result);
726 	ubh_clrblock (UCPI_UBH(ucpi), ucpi->c_freeoff, blkno);
727 	if ((UFS_SB(sb)->s_flags & UFS_CG_MASK) == UFS_CG_44BSD)
728 		ufs_clusteracct (sb, ucpi, blkno, -1);
729 
730 	fs32_sub(sb, &ucg->cg_cs.cs_nbfree, 1);
731 	uspi->cs_total.cs_nbfree--;
732 	fs32_sub(sb, &UFS_SB(sb)->fs_cs(ucpi->c_cgx).cs_nbfree, 1);
733 
734 	if (uspi->fs_magic != UFS2_MAGIC) {
735 		unsigned cylno = ufs_cbtocylno((unsigned)result);
736 
737 		fs16_sub(sb, &ubh_cg_blks(ucpi, cylno,
738 					  ufs_cbtorpos((unsigned)result)), 1);
739 		fs32_sub(sb, &ubh_cg_blktot(ucpi, cylno), 1);
740 	}
741 
742 	UFSD("EXIT, result %llu\n", (unsigned long long)result);
743 
744 	return result;
745 }
746 
747 static unsigned ubh_scanc(struct ufs_sb_private_info *uspi,
748 			  struct ufs_buffer_head *ubh,
749 			  unsigned begin, unsigned size,
750 			  unsigned char *table, unsigned char mask)
751 {
752 	unsigned rest, offset;
753 	unsigned char *cp;
754 
755 
756 	offset = begin & ~uspi->s_fmask;
757 	begin >>= uspi->s_fshift;
758 	for (;;) {
759 		if ((offset + size) < uspi->s_fsize)
760 			rest = size;
761 		else
762 			rest = uspi->s_fsize - offset;
763 		size -= rest;
764 		cp = ubh->bh[begin]->b_data + offset;
765 		while ((table[*cp++] & mask) == 0 && --rest)
766 			;
767 		if (rest || !size)
768 			break;
769 		begin++;
770 		offset = 0;
771 	}
772 	return (size + rest);
773 }
774 
775 /*
776  * Find a block of the specified size in the specified cylinder group.
777  * @sp: pointer to super block
778  * @ucpi: pointer to cylinder group info
779  * @goal: near which block we want find new one
780  * @count: specified size
781  */
782 static u64 ufs_bitmap_search(struct super_block *sb,
783 			     struct ufs_cg_private_info *ucpi,
784 			     u64 goal, unsigned count)
785 {
786 	/*
787 	 * Bit patterns for identifying fragments in the block map
788 	 * used as ((map & mask_arr) == want_arr)
789 	 */
790 	static const int mask_arr[9] = {
791 		0x3, 0x7, 0xf, 0x1f, 0x3f, 0x7f, 0xff, 0x1ff, 0x3ff
792 	};
793 	static const int want_arr[9] = {
794 		0x0, 0x2, 0x6, 0xe, 0x1e, 0x3e, 0x7e, 0xfe, 0x1fe
795 	};
796 	struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
797 	struct ufs_super_block_first *usb1;
798 	struct ufs_cylinder_group *ucg;
799 	unsigned start, length, loc;
800 	unsigned pos, want, blockmap, mask, end;
801 	u64 result;
802 
803 	UFSD("ENTER, cg %u, goal %llu, count %u\n", ucpi->c_cgx,
804 	     (unsigned long long)goal, count);
805 
806 	usb1 = ubh_get_usb_first (uspi);
807 	ucg = ubh_get_ucg(UCPI_UBH(ucpi));
808 
809 	if (goal)
810 		start = ufs_dtogd(uspi, goal) >> 3;
811 	else
812 		start = ucpi->c_frotor >> 3;
813 
814 	length = ((uspi->s_fpg + 7) >> 3) - start;
815 	loc = ubh_scanc(uspi, UCPI_UBH(ucpi), ucpi->c_freeoff + start, length,
816 		(uspi->s_fpb == 8) ? ufs_fragtable_8fpb : ufs_fragtable_other,
817 		1 << (count - 1 + (uspi->s_fpb & 7)));
818 	if (loc == 0) {
819 		length = start + 1;
820 		loc = ubh_scanc(uspi, UCPI_UBH(ucpi), ucpi->c_freeoff, length,
821 				(uspi->s_fpb == 8) ? ufs_fragtable_8fpb :
822 				ufs_fragtable_other,
823 				1 << (count - 1 + (uspi->s_fpb & 7)));
824 		if (loc == 0) {
825 			ufs_error(sb, "ufs_bitmap_search",
826 				  "bitmap corrupted on cg %u, start %u,"
827 				  " length %u, count %u, freeoff %u\n",
828 				  ucpi->c_cgx, start, length, count,
829 				  ucpi->c_freeoff);
830 			return INVBLOCK;
831 		}
832 		start = 0;
833 	}
834 	result = (start + length - loc) << 3;
835 	ucpi->c_frotor = result;
836 
837 	/*
838 	 * found the byte in the map
839 	 */
840 
841 	for (end = result + 8; result < end; result += uspi->s_fpb) {
842 		blockmap = ubh_blkmap(UCPI_UBH(ucpi), ucpi->c_freeoff, result);
843 		blockmap <<= 1;
844 		mask = mask_arr[count];
845 		want = want_arr[count];
846 		for (pos = 0; pos <= uspi->s_fpb - count; pos++) {
847 			if ((blockmap & mask) == want) {
848 				UFSD("EXIT, result %llu\n",
849 				     (unsigned long long)result);
850 				return result + pos;
851  			}
852 			mask <<= 1;
853 			want <<= 1;
854  		}
855  	}
856 
857 	ufs_error(sb, "ufs_bitmap_search", "block not in map on cg %u\n",
858 		  ucpi->c_cgx);
859 	UFSD("EXIT (FAILED)\n");
860 	return INVBLOCK;
861 }
862 
863 static void ufs_clusteracct(struct super_block * sb,
864 	struct ufs_cg_private_info * ucpi, unsigned blkno, int cnt)
865 {
866 	struct ufs_sb_private_info * uspi;
867 	int i, start, end, forw, back;
868 
869 	uspi = UFS_SB(sb)->s_uspi;
870 	if (uspi->s_contigsumsize <= 0)
871 		return;
872 
873 	if (cnt > 0)
874 		ubh_setbit(UCPI_UBH(ucpi), ucpi->c_clusteroff, blkno);
875 	else
876 		ubh_clrbit(UCPI_UBH(ucpi), ucpi->c_clusteroff, blkno);
877 
878 	/*
879 	 * Find the size of the cluster going forward.
880 	 */
881 	start = blkno + 1;
882 	end = start + uspi->s_contigsumsize;
883 	if ( end >= ucpi->c_nclusterblks)
884 		end = ucpi->c_nclusterblks;
885 	i = ubh_find_next_zero_bit (UCPI_UBH(ucpi), ucpi->c_clusteroff, end, start);
886 	if (i > end)
887 		i = end;
888 	forw = i - start;
889 
890 	/*
891 	 * Find the size of the cluster going backward.
892 	 */
893 	start = blkno - 1;
894 	end = start - uspi->s_contigsumsize;
895 	if (end < 0 )
896 		end = -1;
897 	i = ubh_find_last_zero_bit (UCPI_UBH(ucpi), ucpi->c_clusteroff, start, end);
898 	if ( i < end)
899 		i = end;
900 	back = start - i;
901 
902 	/*
903 	 * Account for old cluster and the possibly new forward and
904 	 * back clusters.
905 	 */
906 	i = back + forw + 1;
907 	if (i > uspi->s_contigsumsize)
908 		i = uspi->s_contigsumsize;
909 	fs32_add(sb, (__fs32*)ubh_get_addr(UCPI_UBH(ucpi), ucpi->c_clustersumoff + (i << 2)), cnt);
910 	if (back > 0)
911 		fs32_sub(sb, (__fs32*)ubh_get_addr(UCPI_UBH(ucpi), ucpi->c_clustersumoff + (back << 2)), cnt);
912 	if (forw > 0)
913 		fs32_sub(sb, (__fs32*)ubh_get_addr(UCPI_UBH(ucpi), ucpi->c_clustersumoff + (forw << 2)), cnt);
914 }
915 
916 
917 static unsigned char ufs_fragtable_8fpb[] = {
918 	0x00, 0x01, 0x01, 0x02, 0x01, 0x01, 0x02, 0x04, 0x01, 0x01, 0x01, 0x03, 0x02, 0x03, 0x04, 0x08,
919 	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05, 0x02, 0x03, 0x03, 0x02, 0x04, 0x05, 0x08, 0x10,
920 	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05, 0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
921 	0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06, 0x04, 0x05, 0x05, 0x06, 0x08, 0x09, 0x10, 0x20,
922 	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05, 0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
923 	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05, 0x03, 0x03, 0x03, 0x03, 0x05, 0x05, 0x09, 0x11,
924 	0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06, 0x03, 0x03, 0x03, 0x03, 0x02, 0x03, 0x06, 0x0A,
925 	0x04, 0x05, 0x05, 0x06, 0x05, 0x05, 0x06, 0x04, 0x08, 0x09, 0x09, 0x0A, 0x10, 0x11, 0x20, 0x40,
926 	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05, 0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
927 	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05, 0x03, 0x03, 0x03, 0x03, 0x05, 0x05, 0x09, 0x11,
928 	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05, 0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
929 	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x07, 0x05, 0x05, 0x05, 0x07, 0x09, 0x09, 0x11, 0x21,
930 	0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06, 0x03, 0x03, 0x03, 0x03, 0x02, 0x03, 0x06, 0x0A,
931 	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x07, 0x02, 0x03, 0x03, 0x02, 0x06, 0x07, 0x0A, 0x12,
932 	0x04, 0x05, 0x05, 0x06, 0x05, 0x05, 0x06, 0x04, 0x05, 0x05, 0x05, 0x07, 0x06, 0x07, 0x04, 0x0C,
933 	0x08, 0x09, 0x09, 0x0A, 0x09, 0x09, 0x0A, 0x0C, 0x10, 0x11, 0x11, 0x12, 0x20, 0x21, 0x40, 0x80,
934 };
935 
936 static unsigned char ufs_fragtable_other[] = {
937 	0x00, 0x16, 0x16, 0x2A, 0x16, 0x16, 0x26, 0x4E, 0x16, 0x16, 0x16, 0x3E, 0x2A, 0x3E, 0x4E, 0x8A,
938 	0x16, 0x16, 0x16, 0x3E, 0x16, 0x16, 0x36, 0x5E, 0x16, 0x16, 0x16, 0x3E, 0x3E, 0x3E, 0x5E, 0x9E,
939 	0x16, 0x16, 0x16, 0x3E, 0x16, 0x16, 0x36, 0x5E, 0x16, 0x16, 0x16, 0x3E, 0x3E, 0x3E, 0x5E, 0x9E,
940 	0x2A, 0x3E, 0x3E, 0x2A, 0x3E, 0x3E, 0x2E, 0x6E, 0x3E, 0x3E, 0x3E, 0x3E, 0x2A, 0x3E, 0x6E, 0xAA,
941 	0x16, 0x16, 0x16, 0x3E, 0x16, 0x16, 0x36, 0x5E, 0x16, 0x16, 0x16, 0x3E, 0x3E, 0x3E, 0x5E, 0x9E,
942 	0x16, 0x16, 0x16, 0x3E, 0x16, 0x16, 0x36, 0x5E, 0x16, 0x16, 0x16, 0x3E, 0x3E, 0x3E, 0x5E, 0x9E,
943 	0x26, 0x36, 0x36, 0x2E, 0x36, 0x36, 0x26, 0x6E, 0x36, 0x36, 0x36, 0x3E, 0x2E, 0x3E, 0x6E, 0xAE,
944 	0x4E, 0x5E, 0x5E, 0x6E, 0x5E, 0x5E, 0x6E, 0x4E, 0x5E, 0x5E, 0x5E, 0x7E, 0x6E, 0x7E, 0x4E, 0xCE,
945 	0x16, 0x16, 0x16, 0x3E, 0x16, 0x16, 0x36, 0x5E, 0x16, 0x16, 0x16, 0x3E, 0x3E, 0x3E, 0x5E, 0x9E,
946 	0x16, 0x16, 0x16, 0x3E, 0x16, 0x16, 0x36, 0x5E, 0x16, 0x16, 0x16, 0x3E, 0x3E, 0x3E, 0x5E, 0x9E,
947 	0x16, 0x16, 0x16, 0x3E, 0x16, 0x16, 0x36, 0x5E, 0x16, 0x16, 0x16, 0x3E, 0x3E, 0x3E, 0x5E, 0x9E,
948 	0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x7E, 0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x7E, 0xBE,
949 	0x2A, 0x3E, 0x3E, 0x2A, 0x3E, 0x3E, 0x2E, 0x6E, 0x3E, 0x3E, 0x3E, 0x3E, 0x2A, 0x3E, 0x6E, 0xAA,
950 	0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x7E,	0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x7E, 0xBE,
951 	0x4E, 0x5E, 0x5E, 0x6E, 0x5E, 0x5E, 0x6E, 0x4E, 0x5E, 0x5E, 0x5E, 0x7E, 0x6E, 0x7E, 0x4E, 0xCE,
952 	0x8A, 0x9E, 0x9E, 0xAA, 0x9E, 0x9E, 0xAE, 0xCE, 0x9E, 0x9E, 0x9E, 0xBE, 0xAA, 0xBE, 0xCE, 0x8A,
953 };
954