1 /*
2  *   Copyright (C) International Business Machines Corp., 2000-2004
3  *
4  *   This program is free software;  you can redistribute it and/or modify
5  *   it under the terms of the GNU General Public License as published by
6  *   the Free Software Foundation; either version 2 of the License, or
7  *   (at your option) any later version.
8  *
9  *   This program is distributed in the hope that it will be useful,
10  *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
11  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
12  *   the GNU General Public License for more details.
13  *
14  *   You should have received a copy of the GNU General Public License
15  *   along with this program;  if not, write to the Free Software
16  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17  */
18 
19 #include <linux/fs.h>
20 #include <linux/slab.h>
21 #include "jfs_incore.h"
22 #include "jfs_superblock.h"
23 #include "jfs_dmap.h"
24 #include "jfs_imap.h"
25 #include "jfs_lock.h"
26 #include "jfs_metapage.h"
27 #include "jfs_debug.h"
28 
29 /*
30  *	SERIALIZATION of the Block Allocation Map.
31  *
32  *	the working state of the block allocation map is accessed in
33  *	two directions:
34  *
35  *	1) allocation and free requests that start at the dmap
36  *	   level and move up through the dmap control pages (i.e.
37  *	   the vast majority of requests).
38  *
39  *	2) allocation requests that start at dmap control page
40  *	   level and work down towards the dmaps.
41  *
42  *	the serialization scheme used here is as follows.
43  *
44  *	requests which start at the bottom are serialized against each
45  *	other through buffers and each requests holds onto its buffers
46  *	as it works it way up from a single dmap to the required level
47  *	of dmap control page.
48  *	requests that start at the top are serialized against each other
49  *	and request that start from the bottom by the multiple read/single
50  *	write inode lock of the bmap inode. requests starting at the top
51  *	take this lock in write mode while request starting at the bottom
52  *	take the lock in read mode.  a single top-down request may proceed
53  *	exclusively while multiple bottoms-up requests may proceed
54  *	simultaneously (under the protection of busy buffers).
55  *
56  *	in addition to information found in dmaps and dmap control pages,
57  *	the working state of the block allocation map also includes read/
58  *	write information maintained in the bmap descriptor (i.e. total
59  *	free block count, allocation group level free block counts).
60  *	a single exclusive lock (BMAP_LOCK) is used to guard this information
61  *	in the face of multiple-bottoms up requests.
62  *	(lock ordering: IREAD_LOCK, BMAP_LOCK);
63  *
64  *	accesses to the persistent state of the block allocation map (limited
65  *	to the persistent bitmaps in dmaps) is guarded by (busy) buffers.
66  */
67 
68 #define BMAP_LOCK_INIT(bmp)	mutex_init(&bmp->db_bmaplock)
69 #define BMAP_LOCK(bmp)		mutex_lock(&bmp->db_bmaplock)
70 #define BMAP_UNLOCK(bmp)	mutex_unlock(&bmp->db_bmaplock)
71 
72 /*
73  * forward references
74  */
75 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
76 			int nblocks);
77 static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval);
78 static int dbBackSplit(dmtree_t * tp, int leafno);
79 static int dbJoin(dmtree_t * tp, int leafno, int newval);
80 static void dbAdjTree(dmtree_t * tp, int leafno, int newval);
81 static int dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc,
82 		    int level);
83 static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results);
84 static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
85 		       int nblocks);
86 static int dbAllocNear(struct bmap * bmp, struct dmap * dp, s64 blkno,
87 		       int nblocks,
88 		       int l2nb, s64 * results);
89 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
90 		       int nblocks);
91 static int dbAllocDmapLev(struct bmap * bmp, struct dmap * dp, int nblocks,
92 			  int l2nb,
93 			  s64 * results);
94 static int dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb,
95 		     s64 * results);
96 static int dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno,
97 		      s64 * results);
98 static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks);
99 static int dbFindBits(u32 word, int l2nb);
100 static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno);
101 static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx);
102 static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
103 		      int nblocks);
104 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
105 		      int nblocks);
106 static int dbMaxBud(u8 * cp);
107 s64 dbMapFileSizeToMapSize(struct inode *ipbmap);
108 static int blkstol2(s64 nb);
109 
110 static int cntlz(u32 value);
111 static int cnttz(u32 word);
112 
113 static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
114 			 int nblocks);
115 static int dbInitDmap(struct dmap * dp, s64 blkno, int nblocks);
116 static int dbInitDmapTree(struct dmap * dp);
117 static int dbInitTree(struct dmaptree * dtp);
118 static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i);
119 static int dbGetL2AGSize(s64 nblocks);
120 
121 /*
122  *	buddy table
123  *
124  * table used for determining buddy sizes within characters of
125  * dmap bitmap words.  the characters themselves serve as indexes
126  * into the table, with the table elements yielding the maximum
127  * binary buddy of free bits within the character.
128  */
129 static const s8 budtab[256] = {
130 	3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
131 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
132 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
133 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
134 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
135 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
136 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
137 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
138 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
139 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
140 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
141 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
142 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
143 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
144 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
145 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1
146 };
147 
148 
149 /*
150  * NAME:	dbMount()
151  *
152  * FUNCTION:	initializate the block allocation map.
153  *
154  *		memory is allocated for the in-core bmap descriptor and
155  *		the in-core descriptor is initialized from disk.
156  *
157  * PARAMETERS:
158  *	ipbmap	- pointer to in-core inode for the block map.
159  *
160  * RETURN VALUES:
161  *	0	- success
162  *	-ENOMEM	- insufficient memory
163  *	-EIO	- i/o error
164  */
dbMount(struct inode * ipbmap)165 int dbMount(struct inode *ipbmap)
166 {
167 	struct bmap *bmp;
168 	struct dbmap_disk *dbmp_le;
169 	struct metapage *mp;
170 	int i;
171 
172 	/*
173 	 * allocate/initialize the in-memory bmap descriptor
174 	 */
175 	/* allocate memory for the in-memory bmap descriptor */
176 	bmp = kmalloc(sizeof(struct bmap), GFP_KERNEL);
177 	if (bmp == NULL)
178 		return -ENOMEM;
179 
180 	/* read the on-disk bmap descriptor. */
181 	mp = read_metapage(ipbmap,
182 			   BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
183 			   PSIZE, 0);
184 	if (mp == NULL) {
185 		kfree(bmp);
186 		return -EIO;
187 	}
188 
189 	/* copy the on-disk bmap descriptor to its in-memory version. */
190 	dbmp_le = (struct dbmap_disk *) mp->data;
191 	bmp->db_mapsize = le64_to_cpu(dbmp_le->dn_mapsize);
192 	bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree);
193 	bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage);
194 	bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag);
195 	bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel);
196 	bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag);
197 	bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref);
198 	bmp->db_aglevel = le32_to_cpu(dbmp_le->dn_aglevel);
199 	bmp->db_agheight = le32_to_cpu(dbmp_le->dn_agheight);
200 	bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);
201 	bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart);
202 	bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size);
203 	for (i = 0; i < MAXAG; i++)
204 		bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]);
205 	bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize);
206 	bmp->db_maxfreebud = dbmp_le->dn_maxfreebud;
207 
208 	/* release the buffer. */
209 	release_metapage(mp);
210 
211 	/* bind the bmap inode and the bmap descriptor to each other. */
212 	bmp->db_ipbmap = ipbmap;
213 	JFS_SBI(ipbmap->i_sb)->bmap = bmp;
214 
215 	memset(bmp->db_active, 0, sizeof(bmp->db_active));
216 
217 	/*
218 	 * allocate/initialize the bmap lock
219 	 */
220 	BMAP_LOCK_INIT(bmp);
221 
222 	return (0);
223 }
224 
225 
226 /*
227  * NAME:	dbUnmount()
228  *
229  * FUNCTION:	terminate the block allocation map in preparation for
230  *		file system unmount.
231  *
232  *		the in-core bmap descriptor is written to disk and
233  *		the memory for this descriptor is freed.
234  *
235  * PARAMETERS:
236  *	ipbmap	- pointer to in-core inode for the block map.
237  *
238  * RETURN VALUES:
239  *	0	- success
240  *	-EIO	- i/o error
241  */
dbUnmount(struct inode * ipbmap,int mounterror)242 int dbUnmount(struct inode *ipbmap, int mounterror)
243 {
244 	struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
245 
246 	if (!(mounterror || isReadOnly(ipbmap)))
247 		dbSync(ipbmap);
248 
249 	/*
250 	 * Invalidate the page cache buffers
251 	 */
252 	truncate_inode_pages(ipbmap->i_mapping, 0);
253 
254 	/* free the memory for the in-memory bmap. */
255 	kfree(bmp);
256 
257 	return (0);
258 }
259 
260 /*
261  *	dbSync()
262  */
dbSync(struct inode * ipbmap)263 int dbSync(struct inode *ipbmap)
264 {
265 	struct dbmap_disk *dbmp_le;
266 	struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
267 	struct metapage *mp;
268 	int i;
269 
270 	/*
271 	 * write bmap global control page
272 	 */
273 	/* get the buffer for the on-disk bmap descriptor. */
274 	mp = read_metapage(ipbmap,
275 			   BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
276 			   PSIZE, 0);
277 	if (mp == NULL) {
278 		jfs_err("dbSync: read_metapage failed!");
279 		return -EIO;
280 	}
281 	/* copy the in-memory version of the bmap to the on-disk version */
282 	dbmp_le = (struct dbmap_disk *) mp->data;
283 	dbmp_le->dn_mapsize = cpu_to_le64(bmp->db_mapsize);
284 	dbmp_le->dn_nfree = cpu_to_le64(bmp->db_nfree);
285 	dbmp_le->dn_l2nbperpage = cpu_to_le32(bmp->db_l2nbperpage);
286 	dbmp_le->dn_numag = cpu_to_le32(bmp->db_numag);
287 	dbmp_le->dn_maxlevel = cpu_to_le32(bmp->db_maxlevel);
288 	dbmp_le->dn_maxag = cpu_to_le32(bmp->db_maxag);
289 	dbmp_le->dn_agpref = cpu_to_le32(bmp->db_agpref);
290 	dbmp_le->dn_aglevel = cpu_to_le32(bmp->db_aglevel);
291 	dbmp_le->dn_agheight = cpu_to_le32(bmp->db_agheight);
292 	dbmp_le->dn_agwidth = cpu_to_le32(bmp->db_agwidth);
293 	dbmp_le->dn_agstart = cpu_to_le32(bmp->db_agstart);
294 	dbmp_le->dn_agl2size = cpu_to_le32(bmp->db_agl2size);
295 	for (i = 0; i < MAXAG; i++)
296 		dbmp_le->dn_agfree[i] = cpu_to_le64(bmp->db_agfree[i]);
297 	dbmp_le->dn_agsize = cpu_to_le64(bmp->db_agsize);
298 	dbmp_le->dn_maxfreebud = bmp->db_maxfreebud;
299 
300 	/* write the buffer */
301 	write_metapage(mp);
302 
303 	/*
304 	 * write out dirty pages of bmap
305 	 */
306 	filemap_write_and_wait(ipbmap->i_mapping);
307 
308 	diWriteSpecial(ipbmap, 0);
309 
310 	return (0);
311 }
312 
313 
314 /*
315  * NAME:	dbFree()
316  *
317  * FUNCTION:	free the specified block range from the working block
318  *		allocation map.
319  *
320  *		the blocks will be free from the working map one dmap
321  *		at a time.
322  *
323  * PARAMETERS:
324  *	ip	- pointer to in-core inode;
325  *	blkno	- starting block number to be freed.
326  *	nblocks	- number of blocks to be freed.
327  *
328  * RETURN VALUES:
329  *	0	- success
330  *	-EIO	- i/o error
331  */
dbFree(struct inode * ip,s64 blkno,s64 nblocks)332 int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
333 {
334 	struct metapage *mp;
335 	struct dmap *dp;
336 	int nb, rc;
337 	s64 lblkno, rem;
338 	struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
339 	struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
340 
341 	IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
342 
343 	/* block to be freed better be within the mapsize. */
344 	if (unlikely((blkno == 0) || (blkno + nblocks > bmp->db_mapsize))) {
345 		IREAD_UNLOCK(ipbmap);
346 		printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
347 		       (unsigned long long) blkno,
348 		       (unsigned long long) nblocks);
349 		jfs_error(ip->i_sb,
350 			  "dbFree: block to be freed is outside the map");
351 		return -EIO;
352 	}
353 
354 	/*
355 	 * free the blocks a dmap at a time.
356 	 */
357 	mp = NULL;
358 	for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
359 		/* release previous dmap if any */
360 		if (mp) {
361 			write_metapage(mp);
362 		}
363 
364 		/* get the buffer for the current dmap. */
365 		lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
366 		mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
367 		if (mp == NULL) {
368 			IREAD_UNLOCK(ipbmap);
369 			return -EIO;
370 		}
371 		dp = (struct dmap *) mp->data;
372 
373 		/* determine the number of blocks to be freed from
374 		 * this dmap.
375 		 */
376 		nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
377 
378 		/* free the blocks. */
379 		if ((rc = dbFreeDmap(bmp, dp, blkno, nb))) {
380 			jfs_error(ip->i_sb, "dbFree: error in block map\n");
381 			release_metapage(mp);
382 			IREAD_UNLOCK(ipbmap);
383 			return (rc);
384 		}
385 	}
386 
387 	/* write the last buffer. */
388 	write_metapage(mp);
389 
390 	IREAD_UNLOCK(ipbmap);
391 
392 	return (0);
393 }
394 
395 
396 /*
397  * NAME:	dbUpdatePMap()
398  *
399  * FUNCTION:	update the allocation state (free or allocate) of the
400  *		specified block range in the persistent block allocation map.
401  *
402  *		the blocks will be updated in the persistent map one
403  *		dmap at a time.
404  *
405  * PARAMETERS:
406  *	ipbmap	- pointer to in-core inode for the block map.
407  *	free	- 'true' if block range is to be freed from the persistent
408  *		  map; 'false' if it is to be allocated.
409  *	blkno	- starting block number of the range.
410  *	nblocks	- number of contiguous blocks in the range.
411  *	tblk	- transaction block;
412  *
413  * RETURN VALUES:
414  *	0	- success
415  *	-EIO	- i/o error
416  */
417 int
dbUpdatePMap(struct inode * ipbmap,int free,s64 blkno,s64 nblocks,struct tblock * tblk)418 dbUpdatePMap(struct inode *ipbmap,
419 	     int free, s64 blkno, s64 nblocks, struct tblock * tblk)
420 {
421 	int nblks, dbitno, wbitno, rbits;
422 	int word, nbits, nwords;
423 	struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
424 	s64 lblkno, rem, lastlblkno;
425 	u32 mask;
426 	struct dmap *dp;
427 	struct metapage *mp;
428 	struct jfs_log *log;
429 	int lsn, difft, diffp;
430 	unsigned long flags;
431 
432 	/* the blocks better be within the mapsize. */
433 	if (blkno + nblocks > bmp->db_mapsize) {
434 		printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
435 		       (unsigned long long) blkno,
436 		       (unsigned long long) nblocks);
437 		jfs_error(ipbmap->i_sb,
438 			  "dbUpdatePMap: blocks are outside the map");
439 		return -EIO;
440 	}
441 
442 	/* compute delta of transaction lsn from log syncpt */
443 	lsn = tblk->lsn;
444 	log = (struct jfs_log *) JFS_SBI(tblk->sb)->log;
445 	logdiff(difft, lsn, log);
446 
447 	/*
448 	 * update the block state a dmap at a time.
449 	 */
450 	mp = NULL;
451 	lastlblkno = 0;
452 	for (rem = nblocks; rem > 0; rem -= nblks, blkno += nblks) {
453 		/* get the buffer for the current dmap. */
454 		lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
455 		if (lblkno != lastlblkno) {
456 			if (mp) {
457 				write_metapage(mp);
458 			}
459 
460 			mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE,
461 					   0);
462 			if (mp == NULL)
463 				return -EIO;
464 			metapage_wait_for_io(mp);
465 		}
466 		dp = (struct dmap *) mp->data;
467 
468 		/* determine the bit number and word within the dmap of
469 		 * the starting block.  also determine how many blocks
470 		 * are to be updated within this dmap.
471 		 */
472 		dbitno = blkno & (BPERDMAP - 1);
473 		word = dbitno >> L2DBWORD;
474 		nblks = min(rem, (s64)BPERDMAP - dbitno);
475 
476 		/* update the bits of the dmap words. the first and last
477 		 * words may only have a subset of their bits updated. if
478 		 * this is the case, we'll work against that word (i.e.
479 		 * partial first and/or last) only in a single pass.  a
480 		 * single pass will also be used to update all words that
481 		 * are to have all their bits updated.
482 		 */
483 		for (rbits = nblks; rbits > 0;
484 		     rbits -= nbits, dbitno += nbits) {
485 			/* determine the bit number within the word and
486 			 * the number of bits within the word.
487 			 */
488 			wbitno = dbitno & (DBWORD - 1);
489 			nbits = min(rbits, DBWORD - wbitno);
490 
491 			/* check if only part of the word is to be updated. */
492 			if (nbits < DBWORD) {
493 				/* update (free or allocate) the bits
494 				 * in this word.
495 				 */
496 				mask =
497 				    (ONES << (DBWORD - nbits) >> wbitno);
498 				if (free)
499 					dp->pmap[word] &=
500 					    cpu_to_le32(~mask);
501 				else
502 					dp->pmap[word] |=
503 					    cpu_to_le32(mask);
504 
505 				word += 1;
506 			} else {
507 				/* one or more words are to have all
508 				 * their bits updated.  determine how
509 				 * many words and how many bits.
510 				 */
511 				nwords = rbits >> L2DBWORD;
512 				nbits = nwords << L2DBWORD;
513 
514 				/* update (free or allocate) the bits
515 				 * in these words.
516 				 */
517 				if (free)
518 					memset(&dp->pmap[word], 0,
519 					       nwords * 4);
520 				else
521 					memset(&dp->pmap[word], (int) ONES,
522 					       nwords * 4);
523 
524 				word += nwords;
525 			}
526 		}
527 
528 		/*
529 		 * update dmap lsn
530 		 */
531 		if (lblkno == lastlblkno)
532 			continue;
533 
534 		lastlblkno = lblkno;
535 
536 		LOGSYNC_LOCK(log, flags);
537 		if (mp->lsn != 0) {
538 			/* inherit older/smaller lsn */
539 			logdiff(diffp, mp->lsn, log);
540 			if (difft < diffp) {
541 				mp->lsn = lsn;
542 
543 				/* move bp after tblock in logsync list */
544 				list_move(&mp->synclist, &tblk->synclist);
545 			}
546 
547 			/* inherit younger/larger clsn */
548 			logdiff(difft, tblk->clsn, log);
549 			logdiff(diffp, mp->clsn, log);
550 			if (difft > diffp)
551 				mp->clsn = tblk->clsn;
552 		} else {
553 			mp->log = log;
554 			mp->lsn = lsn;
555 
556 			/* insert bp after tblock in logsync list */
557 			log->count++;
558 			list_add(&mp->synclist, &tblk->synclist);
559 
560 			mp->clsn = tblk->clsn;
561 		}
562 		LOGSYNC_UNLOCK(log, flags);
563 	}
564 
565 	/* write the last buffer. */
566 	if (mp) {
567 		write_metapage(mp);
568 	}
569 
570 	return (0);
571 }
572 
573 
574 /*
575  * NAME:	dbNextAG()
576  *
577  * FUNCTION:	find the preferred allocation group for new allocations.
578  *
579  *		Within the allocation groups, we maintain a preferred
580  *		allocation group which consists of a group with at least
581  *		average free space.  It is the preferred group that we target
582  *		new inode allocation towards.  The tie-in between inode
583  *		allocation and block allocation occurs as we allocate the
584  *		first (data) block of an inode and specify the inode (block)
585  *		as the allocation hint for this block.
586  *
587  *		We try to avoid having more than one open file growing in
588  *		an allocation group, as this will lead to fragmentation.
589  *		This differs from the old OS/2 method of trying to keep
590  *		empty ags around for large allocations.
591  *
592  * PARAMETERS:
593  *	ipbmap	- pointer to in-core inode for the block map.
594  *
595  * RETURN VALUES:
596  *	the preferred allocation group number.
597  */
dbNextAG(struct inode * ipbmap)598 int dbNextAG(struct inode *ipbmap)
599 {
600 	s64 avgfree;
601 	int agpref;
602 	s64 hwm = 0;
603 	int i;
604 	int next_best = -1;
605 	struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
606 
607 	BMAP_LOCK(bmp);
608 
609 	/* determine the average number of free blocks within the ags. */
610 	avgfree = (u32)bmp->db_nfree / bmp->db_numag;
611 
612 	/*
613 	 * if the current preferred ag does not have an active allocator
614 	 * and has at least average freespace, return it
615 	 */
616 	agpref = bmp->db_agpref;
617 	if ((atomic_read(&bmp->db_active[agpref]) == 0) &&
618 	    (bmp->db_agfree[agpref] >= avgfree))
619 		goto unlock;
620 
621 	/* From the last preferred ag, find the next one with at least
622 	 * average free space.
623 	 */
624 	for (i = 0 ; i < bmp->db_numag; i++, agpref++) {
625 		if (agpref == bmp->db_numag)
626 			agpref = 0;
627 
628 		if (atomic_read(&bmp->db_active[agpref]))
629 			/* open file is currently growing in this ag */
630 			continue;
631 		if (bmp->db_agfree[agpref] >= avgfree) {
632 			/* Return this one */
633 			bmp->db_agpref = agpref;
634 			goto unlock;
635 		} else if (bmp->db_agfree[agpref] > hwm) {
636 			/* Less than avg. freespace, but best so far */
637 			hwm = bmp->db_agfree[agpref];
638 			next_best = agpref;
639 		}
640 	}
641 
642 	/*
643 	 * If no inactive ag was found with average freespace, use the
644 	 * next best
645 	 */
646 	if (next_best != -1)
647 		bmp->db_agpref = next_best;
648 	/* else leave db_agpref unchanged */
649 unlock:
650 	BMAP_UNLOCK(bmp);
651 
652 	/* return the preferred group.
653 	 */
654 	return (bmp->db_agpref);
655 }
656 
657 /*
658  * NAME:	dbAlloc()
659  *
660  * FUNCTION:	attempt to allocate a specified number of contiguous free
661  *		blocks from the working allocation block map.
662  *
663  *		the block allocation policy uses hints and a multi-step
664  *		approach.
665  *
666  *		for allocation requests smaller than the number of blocks
667  *		per dmap, we first try to allocate the new blocks
668  *		immediately following the hint.  if these blocks are not
669  *		available, we try to allocate blocks near the hint.  if
670  *		no blocks near the hint are available, we next try to
671  *		allocate within the same dmap as contains the hint.
672  *
673  *		if no blocks are available in the dmap or the allocation
674  *		request is larger than the dmap size, we try to allocate
675  *		within the same allocation group as contains the hint. if
676  *		this does not succeed, we finally try to allocate anywhere
677  *		within the aggregate.
678  *
679  *		we also try to allocate anywhere within the aggregate for
680  *		for allocation requests larger than the allocation group
681  *		size or requests that specify no hint value.
682  *
683  * PARAMETERS:
684  *	ip	- pointer to in-core inode;
685  *	hint	- allocation hint.
686  *	nblocks	- number of contiguous blocks in the range.
687  *	results	- on successful return, set to the starting block number
688  *		  of the newly allocated contiguous range.
689  *
690  * RETURN VALUES:
691  *	0	- success
692  *	-ENOSPC	- insufficient disk resources
693  *	-EIO	- i/o error
694  */
dbAlloc(struct inode * ip,s64 hint,s64 nblocks,s64 * results)695 int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results)
696 {
697 	int rc, agno;
698 	struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
699 	struct bmap *bmp;
700 	struct metapage *mp;
701 	s64 lblkno, blkno;
702 	struct dmap *dp;
703 	int l2nb;
704 	s64 mapSize;
705 	int writers;
706 
707 	/* assert that nblocks is valid */
708 	assert(nblocks > 0);
709 
710 	/* get the log2 number of blocks to be allocated.
711 	 * if the number of blocks is not a log2 multiple,
712 	 * it will be rounded up to the next log2 multiple.
713 	 */
714 	l2nb = BLKSTOL2(nblocks);
715 
716 	bmp = JFS_SBI(ip->i_sb)->bmap;
717 
718 	mapSize = bmp->db_mapsize;
719 
720 	/* the hint should be within the map */
721 	if (hint >= mapSize) {
722 		jfs_error(ip->i_sb, "dbAlloc: the hint is outside the map");
723 		return -EIO;
724 	}
725 
726 	/* if the number of blocks to be allocated is greater than the
727 	 * allocation group size, try to allocate anywhere.
728 	 */
729 	if (l2nb > bmp->db_agl2size) {
730 		IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
731 
732 		rc = dbAllocAny(bmp, nblocks, l2nb, results);
733 
734 		goto write_unlock;
735 	}
736 
737 	/*
738 	 * If no hint, let dbNextAG recommend an allocation group
739 	 */
740 	if (hint == 0)
741 		goto pref_ag;
742 
743 	/* we would like to allocate close to the hint.  adjust the
744 	 * hint to the block following the hint since the allocators
745 	 * will start looking for free space starting at this point.
746 	 */
747 	blkno = hint + 1;
748 
749 	if (blkno >= bmp->db_mapsize)
750 		goto pref_ag;
751 
752 	agno = blkno >> bmp->db_agl2size;
753 
754 	/* check if blkno crosses over into a new allocation group.
755 	 * if so, check if we should allow allocations within this
756 	 * allocation group.
757 	 */
758 	if ((blkno & (bmp->db_agsize - 1)) == 0)
759 		/* check if the AG is currently being written to.
760 		 * if so, call dbNextAG() to find a non-busy
761 		 * AG with sufficient free space.
762 		 */
763 		if (atomic_read(&bmp->db_active[agno]))
764 			goto pref_ag;
765 
766 	/* check if the allocation request size can be satisfied from a
767 	 * single dmap.  if so, try to allocate from the dmap containing
768 	 * the hint using a tiered strategy.
769 	 */
770 	if (nblocks <= BPERDMAP) {
771 		IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
772 
773 		/* get the buffer for the dmap containing the hint.
774 		 */
775 		rc = -EIO;
776 		lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
777 		mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
778 		if (mp == NULL)
779 			goto read_unlock;
780 
781 		dp = (struct dmap *) mp->data;
782 
783 		/* first, try to satisfy the allocation request with the
784 		 * blocks beginning at the hint.
785 		 */
786 		if ((rc = dbAllocNext(bmp, dp, blkno, (int) nblocks))
787 		    != -ENOSPC) {
788 			if (rc == 0) {
789 				*results = blkno;
790 				mark_metapage_dirty(mp);
791 			}
792 
793 			release_metapage(mp);
794 			goto read_unlock;
795 		}
796 
797 		writers = atomic_read(&bmp->db_active[agno]);
798 		if ((writers > 1) ||
799 		    ((writers == 1) && (JFS_IP(ip)->active_ag != agno))) {
800 			/*
801 			 * Someone else is writing in this allocation
802 			 * group.  To avoid fragmenting, try another ag
803 			 */
804 			release_metapage(mp);
805 			IREAD_UNLOCK(ipbmap);
806 			goto pref_ag;
807 		}
808 
809 		/* next, try to satisfy the allocation request with blocks
810 		 * near the hint.
811 		 */
812 		if ((rc =
813 		     dbAllocNear(bmp, dp, blkno, (int) nblocks, l2nb, results))
814 		    != -ENOSPC) {
815 			if (rc == 0)
816 				mark_metapage_dirty(mp);
817 
818 			release_metapage(mp);
819 			goto read_unlock;
820 		}
821 
822 		/* try to satisfy the allocation request with blocks within
823 		 * the same dmap as the hint.
824 		 */
825 		if ((rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results))
826 		    != -ENOSPC) {
827 			if (rc == 0)
828 				mark_metapage_dirty(mp);
829 
830 			release_metapage(mp);
831 			goto read_unlock;
832 		}
833 
834 		release_metapage(mp);
835 		IREAD_UNLOCK(ipbmap);
836 	}
837 
838 	/* try to satisfy the allocation request with blocks within
839 	 * the same allocation group as the hint.
840 	 */
841 	IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
842 	if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) != -ENOSPC)
843 		goto write_unlock;
844 
845 	IWRITE_UNLOCK(ipbmap);
846 
847 
848       pref_ag:
849 	/*
850 	 * Let dbNextAG recommend a preferred allocation group
851 	 */
852 	agno = dbNextAG(ipbmap);
853 	IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
854 
855 	/* Try to allocate within this allocation group.  if that fails, try to
856 	 * allocate anywhere in the map.
857 	 */
858 	if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) == -ENOSPC)
859 		rc = dbAllocAny(bmp, nblocks, l2nb, results);
860 
861       write_unlock:
862 	IWRITE_UNLOCK(ipbmap);
863 
864 	return (rc);
865 
866       read_unlock:
867 	IREAD_UNLOCK(ipbmap);
868 
869 	return (rc);
870 }
871 
872 #ifdef _NOTYET
873 /*
874  * NAME:	dbAllocExact()
875  *
876  * FUNCTION:	try to allocate the requested extent;
877  *
878  * PARAMETERS:
879  *	ip	- pointer to in-core inode;
880  *	blkno	- extent address;
881  *	nblocks	- extent length;
882  *
883  * RETURN VALUES:
884  *	0	- success
885  *	-ENOSPC	- insufficient disk resources
886  *	-EIO	- i/o error
887  */
dbAllocExact(struct inode * ip,s64 blkno,int nblocks)888 int dbAllocExact(struct inode *ip, s64 blkno, int nblocks)
889 {
890 	int rc;
891 	struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
892 	struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
893 	struct dmap *dp;
894 	s64 lblkno;
895 	struct metapage *mp;
896 
897 	IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
898 
899 	/*
900 	 * validate extent request:
901 	 *
902 	 * note: defragfs policy:
903 	 *  max 64 blocks will be moved.
904 	 *  allocation request size must be satisfied from a single dmap.
905 	 */
906 	if (nblocks <= 0 || nblocks > BPERDMAP || blkno >= bmp->db_mapsize) {
907 		IREAD_UNLOCK(ipbmap);
908 		return -EINVAL;
909 	}
910 
911 	if (nblocks > ((s64) 1 << bmp->db_maxfreebud)) {
912 		/* the free space is no longer available */
913 		IREAD_UNLOCK(ipbmap);
914 		return -ENOSPC;
915 	}
916 
917 	/* read in the dmap covering the extent */
918 	lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
919 	mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
920 	if (mp == NULL) {
921 		IREAD_UNLOCK(ipbmap);
922 		return -EIO;
923 	}
924 	dp = (struct dmap *) mp->data;
925 
926 	/* try to allocate the requested extent */
927 	rc = dbAllocNext(bmp, dp, blkno, nblocks);
928 
929 	IREAD_UNLOCK(ipbmap);
930 
931 	if (rc == 0)
932 		mark_metapage_dirty(mp);
933 
934 	release_metapage(mp);
935 
936 	return (rc);
937 }
938 #endif /* _NOTYET */
939 
940 /*
941  * NAME:	dbReAlloc()
942  *
943  * FUNCTION:	attempt to extend a current allocation by a specified
944  *		number of blocks.
945  *
946  *		this routine attempts to satisfy the allocation request
947  *		by first trying to extend the existing allocation in
948  *		place by allocating the additional blocks as the blocks
949  *		immediately following the current allocation.  if these
950  *		blocks are not available, this routine will attempt to
951  *		allocate a new set of contiguous blocks large enough
952  *		to cover the existing allocation plus the additional
953  *		number of blocks required.
954  *
955  * PARAMETERS:
956  *	ip	    -  pointer to in-core inode requiring allocation.
957  *	blkno	    -  starting block of the current allocation.
958  *	nblocks	    -  number of contiguous blocks within the current
959  *		       allocation.
960  *	addnblocks  -  number of blocks to add to the allocation.
961  *	results	-      on successful return, set to the starting block number
962  *		       of the existing allocation if the existing allocation
963  *		       was extended in place or to a newly allocated contiguous
964  *		       range if the existing allocation could not be extended
965  *		       in place.
966  *
967  * RETURN VALUES:
968  *	0	- success
969  *	-ENOSPC	- insufficient disk resources
970  *	-EIO	- i/o error
971  */
972 int
dbReAlloc(struct inode * ip,s64 blkno,s64 nblocks,s64 addnblocks,s64 * results)973 dbReAlloc(struct inode *ip,
974 	  s64 blkno, s64 nblocks, s64 addnblocks, s64 * results)
975 {
976 	int rc;
977 
978 	/* try to extend the allocation in place.
979 	 */
980 	if ((rc = dbExtend(ip, blkno, nblocks, addnblocks)) == 0) {
981 		*results = blkno;
982 		return (0);
983 	} else {
984 		if (rc != -ENOSPC)
985 			return (rc);
986 	}
987 
988 	/* could not extend the allocation in place, so allocate a
989 	 * new set of blocks for the entire request (i.e. try to get
990 	 * a range of contiguous blocks large enough to cover the
991 	 * existing allocation plus the additional blocks.)
992 	 */
993 	return (dbAlloc
994 		(ip, blkno + nblocks - 1, addnblocks + nblocks, results));
995 }
996 
997 
998 /*
999  * NAME:	dbExtend()
1000  *
1001  * FUNCTION:	attempt to extend a current allocation by a specified
1002  *		number of blocks.
1003  *
1004  *		this routine attempts to satisfy the allocation request
1005  *		by first trying to extend the existing allocation in
1006  *		place by allocating the additional blocks as the blocks
1007  *		immediately following the current allocation.
1008  *
1009  * PARAMETERS:
1010  *	ip	    -  pointer to in-core inode requiring allocation.
1011  *	blkno	    -  starting block of the current allocation.
1012  *	nblocks	    -  number of contiguous blocks within the current
1013  *		       allocation.
1014  *	addnblocks  -  number of blocks to add to the allocation.
1015  *
1016  * RETURN VALUES:
1017  *	0	- success
1018  *	-ENOSPC	- insufficient disk resources
1019  *	-EIO	- i/o error
1020  */
dbExtend(struct inode * ip,s64 blkno,s64 nblocks,s64 addnblocks)1021 static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks)
1022 {
1023 	struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
1024 	s64 lblkno, lastblkno, extblkno;
1025 	uint rel_block;
1026 	struct metapage *mp;
1027 	struct dmap *dp;
1028 	int rc;
1029 	struct inode *ipbmap = sbi->ipbmap;
1030 	struct bmap *bmp;
1031 
1032 	/*
1033 	 * We don't want a non-aligned extent to cross a page boundary
1034 	 */
1035 	if (((rel_block = blkno & (sbi->nbperpage - 1))) &&
1036 	    (rel_block + nblocks + addnblocks > sbi->nbperpage))
1037 		return -ENOSPC;
1038 
1039 	/* get the last block of the current allocation */
1040 	lastblkno = blkno + nblocks - 1;
1041 
1042 	/* determine the block number of the block following
1043 	 * the existing allocation.
1044 	 */
1045 	extblkno = lastblkno + 1;
1046 
1047 	IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
1048 
1049 	/* better be within the file system */
1050 	bmp = sbi->bmap;
1051 	if (lastblkno < 0 || lastblkno >= bmp->db_mapsize) {
1052 		IREAD_UNLOCK(ipbmap);
1053 		jfs_error(ip->i_sb,
1054 			  "dbExtend: the block is outside the filesystem");
1055 		return -EIO;
1056 	}
1057 
1058 	/* we'll attempt to extend the current allocation in place by
1059 	 * allocating the additional blocks as the blocks immediately
1060 	 * following the current allocation.  we only try to extend the
1061 	 * current allocation in place if the number of additional blocks
1062 	 * can fit into a dmap, the last block of the current allocation
1063 	 * is not the last block of the file system, and the start of the
1064 	 * inplace extension is not on an allocation group boundary.
1065 	 */
1066 	if (addnblocks > BPERDMAP || extblkno >= bmp->db_mapsize ||
1067 	    (extblkno & (bmp->db_agsize - 1)) == 0) {
1068 		IREAD_UNLOCK(ipbmap);
1069 		return -ENOSPC;
1070 	}
1071 
1072 	/* get the buffer for the dmap containing the first block
1073 	 * of the extension.
1074 	 */
1075 	lblkno = BLKTODMAP(extblkno, bmp->db_l2nbperpage);
1076 	mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
1077 	if (mp == NULL) {
1078 		IREAD_UNLOCK(ipbmap);
1079 		return -EIO;
1080 	}
1081 
1082 	dp = (struct dmap *) mp->data;
1083 
1084 	/* try to allocate the blocks immediately following the
1085 	 * current allocation.
1086 	 */
1087 	rc = dbAllocNext(bmp, dp, extblkno, (int) addnblocks);
1088 
1089 	IREAD_UNLOCK(ipbmap);
1090 
1091 	/* were we successful ? */
1092 	if (rc == 0)
1093 		write_metapage(mp);
1094 	else
1095 		/* we were not successful */
1096 		release_metapage(mp);
1097 
1098 
1099 	return (rc);
1100 }
1101 
1102 
1103 /*
1104  * NAME:	dbAllocNext()
1105  *
1106  * FUNCTION:	attempt to allocate the blocks of the specified block
1107  *		range within a dmap.
1108  *
1109  * PARAMETERS:
1110  *	bmp	-  pointer to bmap descriptor
1111  *	dp	-  pointer to dmap.
1112  *	blkno	-  starting block number of the range.
1113  *	nblocks	-  number of contiguous free blocks of the range.
1114  *
1115  * RETURN VALUES:
1116  *	0	- success
1117  *	-ENOSPC	- insufficient disk resources
1118  *	-EIO	- i/o error
1119  *
1120  * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1121  */
dbAllocNext(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)1122 static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
1123 		       int nblocks)
1124 {
1125 	int dbitno, word, rembits, nb, nwords, wbitno, nw;
1126 	int l2size;
1127 	s8 *leaf;
1128 	u32 mask;
1129 
1130 	if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1131 		jfs_error(bmp->db_ipbmap->i_sb,
1132 			  "dbAllocNext: Corrupt dmap page");
1133 		return -EIO;
1134 	}
1135 
1136 	/* pick up a pointer to the leaves of the dmap tree.
1137 	 */
1138 	leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1139 
1140 	/* determine the bit number and word within the dmap of the
1141 	 * starting block.
1142 	 */
1143 	dbitno = blkno & (BPERDMAP - 1);
1144 	word = dbitno >> L2DBWORD;
1145 
1146 	/* check if the specified block range is contained within
1147 	 * this dmap.
1148 	 */
1149 	if (dbitno + nblocks > BPERDMAP)
1150 		return -ENOSPC;
1151 
1152 	/* check if the starting leaf indicates that anything
1153 	 * is free.
1154 	 */
1155 	if (leaf[word] == NOFREE)
1156 		return -ENOSPC;
1157 
1158 	/* check the dmaps words corresponding to block range to see
1159 	 * if the block range is free.  not all bits of the first and
1160 	 * last words may be contained within the block range.  if this
1161 	 * is the case, we'll work against those words (i.e. partial first
1162 	 * and/or last) on an individual basis (a single pass) and examine
1163 	 * the actual bits to determine if they are free.  a single pass
1164 	 * will be used for all dmap words fully contained within the
1165 	 * specified range.  within this pass, the leaves of the dmap
1166 	 * tree will be examined to determine if the blocks are free. a
1167 	 * single leaf may describe the free space of multiple dmap
1168 	 * words, so we may visit only a subset of the actual leaves
1169 	 * corresponding to the dmap words of the block range.
1170 	 */
1171 	for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
1172 		/* determine the bit number within the word and
1173 		 * the number of bits within the word.
1174 		 */
1175 		wbitno = dbitno & (DBWORD - 1);
1176 		nb = min(rembits, DBWORD - wbitno);
1177 
1178 		/* check if only part of the word is to be examined.
1179 		 */
1180 		if (nb < DBWORD) {
1181 			/* check if the bits are free.
1182 			 */
1183 			mask = (ONES << (DBWORD - nb) >> wbitno);
1184 			if ((mask & ~le32_to_cpu(dp->wmap[word])) != mask)
1185 				return -ENOSPC;
1186 
1187 			word += 1;
1188 		} else {
1189 			/* one or more dmap words are fully contained
1190 			 * within the block range.  determine how many
1191 			 * words and how many bits.
1192 			 */
1193 			nwords = rembits >> L2DBWORD;
1194 			nb = nwords << L2DBWORD;
1195 
1196 			/* now examine the appropriate leaves to determine
1197 			 * if the blocks are free.
1198 			 */
1199 			while (nwords > 0) {
1200 				/* does the leaf describe any free space ?
1201 				 */
1202 				if (leaf[word] < BUDMIN)
1203 					return -ENOSPC;
1204 
1205 				/* determine the l2 number of bits provided
1206 				 * by this leaf.
1207 				 */
1208 				l2size =
1209 				    min((int)leaf[word], NLSTOL2BSZ(nwords));
1210 
1211 				/* determine how many words were handled.
1212 				 */
1213 				nw = BUDSIZE(l2size, BUDMIN);
1214 
1215 				nwords -= nw;
1216 				word += nw;
1217 			}
1218 		}
1219 	}
1220 
1221 	/* allocate the blocks.
1222 	 */
1223 	return (dbAllocDmap(bmp, dp, blkno, nblocks));
1224 }
1225 
1226 
1227 /*
1228  * NAME:	dbAllocNear()
1229  *
1230  * FUNCTION:	attempt to allocate a number of contiguous free blocks near
1231  *		a specified block (hint) within a dmap.
1232  *
1233  *		starting with the dmap leaf that covers the hint, we'll
1234  *		check the next four contiguous leaves for sufficient free
1235  *		space.  if sufficient free space is found, we'll allocate
1236  *		the desired free space.
1237  *
1238  * PARAMETERS:
1239  *	bmp	-  pointer to bmap descriptor
1240  *	dp	-  pointer to dmap.
1241  *	blkno	-  block number to allocate near.
1242  *	nblocks	-  actual number of contiguous free blocks desired.
1243  *	l2nb	-  log2 number of contiguous free blocks desired.
1244  *	results	-  on successful return, set to the starting block number
1245  *		   of the newly allocated range.
1246  *
1247  * RETURN VALUES:
1248  *	0	- success
1249  *	-ENOSPC	- insufficient disk resources
1250  *	-EIO	- i/o error
1251  *
1252  * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1253  */
1254 static int
dbAllocNear(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks,int l2nb,s64 * results)1255 dbAllocNear(struct bmap * bmp,
1256 	    struct dmap * dp, s64 blkno, int nblocks, int l2nb, s64 * results)
1257 {
1258 	int word, lword, rc;
1259 	s8 *leaf;
1260 
1261 	if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1262 		jfs_error(bmp->db_ipbmap->i_sb,
1263 			  "dbAllocNear: Corrupt dmap page");
1264 		return -EIO;
1265 	}
1266 
1267 	leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1268 
1269 	/* determine the word within the dmap that holds the hint
1270 	 * (i.e. blkno).  also, determine the last word in the dmap
1271 	 * that we'll include in our examination.
1272 	 */
1273 	word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
1274 	lword = min(word + 4, LPERDMAP);
1275 
1276 	/* examine the leaves for sufficient free space.
1277 	 */
1278 	for (; word < lword; word++) {
1279 		/* does the leaf describe sufficient free space ?
1280 		 */
1281 		if (leaf[word] < l2nb)
1282 			continue;
1283 
1284 		/* determine the block number within the file system
1285 		 * of the first block described by this dmap word.
1286 		 */
1287 		blkno = le64_to_cpu(dp->start) + (word << L2DBWORD);
1288 
1289 		/* if not all bits of the dmap word are free, get the
1290 		 * starting bit number within the dmap word of the required
1291 		 * string of free bits and adjust the block number with the
1292 		 * value.
1293 		 */
1294 		if (leaf[word] < BUDMIN)
1295 			blkno +=
1296 			    dbFindBits(le32_to_cpu(dp->wmap[word]), l2nb);
1297 
1298 		/* allocate the blocks.
1299 		 */
1300 		if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1301 			*results = blkno;
1302 
1303 		return (rc);
1304 	}
1305 
1306 	return -ENOSPC;
1307 }
1308 
1309 
1310 /*
1311  * NAME:	dbAllocAG()
1312  *
1313  * FUNCTION:	attempt to allocate the specified number of contiguous
1314  *		free blocks within the specified allocation group.
1315  *
1316  *		unless the allocation group size is equal to the number
1317  *		of blocks per dmap, the dmap control pages will be used to
1318  *		find the required free space, if available.  we start the
1319  *		search at the highest dmap control page level which
1320  *		distinctly describes the allocation group's free space
1321  *		(i.e. the highest level at which the allocation group's
1322  *		free space is not mixed in with that of any other group).
1323  *		in addition, we start the search within this level at a
1324  *		height of the dmapctl dmtree at which the nodes distinctly
1325  *		describe the allocation group's free space.  at this height,
1326  *		the allocation group's free space may be represented by 1
1327  *		or two sub-trees, depending on the allocation group size.
1328  *		we search the top nodes of these subtrees left to right for
1329  *		sufficient free space.  if sufficient free space is found,
1330  *		the subtree is searched to find the leftmost leaf that
1331  *		has free space.  once we have made it to the leaf, we
1332  *		move the search to the next lower level dmap control page
1333  *		corresponding to this leaf.  we continue down the dmap control
1334  *		pages until we find the dmap that contains or starts the
1335  *		sufficient free space and we allocate at this dmap.
1336  *
1337  *		if the allocation group size is equal to the dmap size,
1338  *		we'll start at the dmap corresponding to the allocation
1339  *		group and attempt the allocation at this level.
1340  *
1341  *		the dmap control page search is also not performed if the
1342  *		allocation group is completely free and we go to the first
1343  *		dmap of the allocation group to do the allocation.  this is
1344  *		done because the allocation group may be part (not the first
1345  *		part) of a larger binary buddy system, causing the dmap
1346  *		control pages to indicate no free space (NOFREE) within
1347  *		the allocation group.
1348  *
1349  * PARAMETERS:
1350  *	bmp	-  pointer to bmap descriptor
1351  *	agno	- allocation group number.
1352  *	nblocks	-  actual number of contiguous free blocks desired.
1353  *	l2nb	-  log2 number of contiguous free blocks desired.
1354  *	results	-  on successful return, set to the starting block number
1355  *		   of the newly allocated range.
1356  *
1357  * RETURN VALUES:
1358  *	0	- success
1359  *	-ENOSPC	- insufficient disk resources
1360  *	-EIO	- i/o error
1361  *
1362  * note: IWRITE_LOCK(ipmap) held on entry/exit;
1363  */
1364 static int
dbAllocAG(struct bmap * bmp,int agno,s64 nblocks,int l2nb,s64 * results)1365 dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, s64 * results)
1366 {
1367 	struct metapage *mp;
1368 	struct dmapctl *dcp;
1369 	int rc, ti, i, k, m, n, agperlev;
1370 	s64 blkno, lblkno;
1371 	int budmin;
1372 
1373 	/* allocation request should not be for more than the
1374 	 * allocation group size.
1375 	 */
1376 	if (l2nb > bmp->db_agl2size) {
1377 		jfs_error(bmp->db_ipbmap->i_sb,
1378 			  "dbAllocAG: allocation request is larger than the "
1379 			  "allocation group size");
1380 		return -EIO;
1381 	}
1382 
1383 	/* determine the starting block number of the allocation
1384 	 * group.
1385 	 */
1386 	blkno = (s64) agno << bmp->db_agl2size;
1387 
1388 	/* check if the allocation group size is the minimum allocation
1389 	 * group size or if the allocation group is completely free. if
1390 	 * the allocation group size is the minimum size of BPERDMAP (i.e.
1391 	 * 1 dmap), there is no need to search the dmap control page (below)
1392 	 * that fully describes the allocation group since the allocation
1393 	 * group is already fully described by a dmap.  in this case, we
1394 	 * just call dbAllocCtl() to search the dmap tree and allocate the
1395 	 * required space if available.
1396 	 *
1397 	 * if the allocation group is completely free, dbAllocCtl() is
1398 	 * also called to allocate the required space.  this is done for
1399 	 * two reasons.  first, it makes no sense searching the dmap control
1400 	 * pages for free space when we know that free space exists.  second,
1401 	 * the dmap control pages may indicate that the allocation group
1402 	 * has no free space if the allocation group is part (not the first
1403 	 * part) of a larger binary buddy system.
1404 	 */
1405 	if (bmp->db_agsize == BPERDMAP
1406 	    || bmp->db_agfree[agno] == bmp->db_agsize) {
1407 		rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1408 		if ((rc == -ENOSPC) &&
1409 		    (bmp->db_agfree[agno] == bmp->db_agsize)) {
1410 			printk(KERN_ERR "blkno = %Lx, blocks = %Lx\n",
1411 			       (unsigned long long) blkno,
1412 			       (unsigned long long) nblocks);
1413 			jfs_error(bmp->db_ipbmap->i_sb,
1414 				  "dbAllocAG: dbAllocCtl failed in free AG");
1415 		}
1416 		return (rc);
1417 	}
1418 
1419 	/* the buffer for the dmap control page that fully describes the
1420 	 * allocation group.
1421 	 */
1422 	lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, bmp->db_aglevel);
1423 	mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1424 	if (mp == NULL)
1425 		return -EIO;
1426 	dcp = (struct dmapctl *) mp->data;
1427 	budmin = dcp->budmin;
1428 
1429 	if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1430 		jfs_error(bmp->db_ipbmap->i_sb,
1431 			  "dbAllocAG: Corrupt dmapctl page");
1432 		release_metapage(mp);
1433 		return -EIO;
1434 	}
1435 
1436 	/* search the subtree(s) of the dmap control page that describes
1437 	 * the allocation group, looking for sufficient free space.  to begin,
1438 	 * determine how many allocation groups are represented in a dmap
1439 	 * control page at the control page level (i.e. L0, L1, L2) that
1440 	 * fully describes an allocation group. next, determine the starting
1441 	 * tree index of this allocation group within the control page.
1442 	 */
1443 	agperlev =
1444 	    (1 << (L2LPERCTL - (bmp->db_agheight << 1))) / bmp->db_agwidth;
1445 	ti = bmp->db_agstart + bmp->db_agwidth * (agno & (agperlev - 1));
1446 
1447 	/* dmap control page trees fan-out by 4 and a single allocation
1448 	 * group may be described by 1 or 2 subtrees within the ag level
1449 	 * dmap control page, depending upon the ag size. examine the ag's
1450 	 * subtrees for sufficient free space, starting with the leftmost
1451 	 * subtree.
1452 	 */
1453 	for (i = 0; i < bmp->db_agwidth; i++, ti++) {
1454 		/* is there sufficient free space ?
1455 		 */
1456 		if (l2nb > dcp->stree[ti])
1457 			continue;
1458 
1459 		/* sufficient free space found in a subtree. now search down
1460 		 * the subtree to find the leftmost leaf that describes this
1461 		 * free space.
1462 		 */
1463 		for (k = bmp->db_agheight; k > 0; k--) {
1464 			for (n = 0, m = (ti << 2) + 1; n < 4; n++) {
1465 				if (l2nb <= dcp->stree[m + n]) {
1466 					ti = m + n;
1467 					break;
1468 				}
1469 			}
1470 			if (n == 4) {
1471 				jfs_error(bmp->db_ipbmap->i_sb,
1472 					  "dbAllocAG: failed descending stree");
1473 				release_metapage(mp);
1474 				return -EIO;
1475 			}
1476 		}
1477 
1478 		/* determine the block number within the file system
1479 		 * that corresponds to this leaf.
1480 		 */
1481 		if (bmp->db_aglevel == 2)
1482 			blkno = 0;
1483 		else if (bmp->db_aglevel == 1)
1484 			blkno &= ~(MAXL1SIZE - 1);
1485 		else		/* bmp->db_aglevel == 0 */
1486 			blkno &= ~(MAXL0SIZE - 1);
1487 
1488 		blkno +=
1489 		    ((s64) (ti - le32_to_cpu(dcp->leafidx))) << budmin;
1490 
1491 		/* release the buffer in preparation for going down
1492 		 * the next level of dmap control pages.
1493 		 */
1494 		release_metapage(mp);
1495 
1496 		/* check if we need to continue to search down the lower
1497 		 * level dmap control pages.  we need to if the number of
1498 		 * blocks required is less than maximum number of blocks
1499 		 * described at the next lower level.
1500 		 */
1501 		if (l2nb < budmin) {
1502 
1503 			/* search the lower level dmap control pages to get
1504 			 * the starting block number of the dmap that
1505 			 * contains or starts off the free space.
1506 			 */
1507 			if ((rc =
1508 			     dbFindCtl(bmp, l2nb, bmp->db_aglevel - 1,
1509 				       &blkno))) {
1510 				if (rc == -ENOSPC) {
1511 					jfs_error(bmp->db_ipbmap->i_sb,
1512 						  "dbAllocAG: control page "
1513 						  "inconsistent");
1514 					return -EIO;
1515 				}
1516 				return (rc);
1517 			}
1518 		}
1519 
1520 		/* allocate the blocks.
1521 		 */
1522 		rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1523 		if (rc == -ENOSPC) {
1524 			jfs_error(bmp->db_ipbmap->i_sb,
1525 				  "dbAllocAG: unable to allocate blocks");
1526 			rc = -EIO;
1527 		}
1528 		return (rc);
1529 	}
1530 
1531 	/* no space in the allocation group.  release the buffer and
1532 	 * return -ENOSPC.
1533 	 */
1534 	release_metapage(mp);
1535 
1536 	return -ENOSPC;
1537 }
1538 
1539 
1540 /*
1541  * NAME:	dbAllocAny()
1542  *
1543  * FUNCTION:	attempt to allocate the specified number of contiguous
1544  *		free blocks anywhere in the file system.
1545  *
1546  *		dbAllocAny() attempts to find the sufficient free space by
1547  *		searching down the dmap control pages, starting with the
1548  *		highest level (i.e. L0, L1, L2) control page.  if free space
1549  *		large enough to satisfy the desired free space is found, the
1550  *		desired free space is allocated.
1551  *
1552  * PARAMETERS:
1553  *	bmp	-  pointer to bmap descriptor
1554  *	nblocks	 -  actual number of contiguous free blocks desired.
1555  *	l2nb	 -  log2 number of contiguous free blocks desired.
1556  *	results	-  on successful return, set to the starting block number
1557  *		   of the newly allocated range.
1558  *
1559  * RETURN VALUES:
1560  *	0	- success
1561  *	-ENOSPC	- insufficient disk resources
1562  *	-EIO	- i/o error
1563  *
1564  * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1565  */
dbAllocAny(struct bmap * bmp,s64 nblocks,int l2nb,s64 * results)1566 static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results)
1567 {
1568 	int rc;
1569 	s64 blkno = 0;
1570 
1571 	/* starting with the top level dmap control page, search
1572 	 * down the dmap control levels for sufficient free space.
1573 	 * if free space is found, dbFindCtl() returns the starting
1574 	 * block number of the dmap that contains or starts off the
1575 	 * range of free space.
1576 	 */
1577 	if ((rc = dbFindCtl(bmp, l2nb, bmp->db_maxlevel, &blkno)))
1578 		return (rc);
1579 
1580 	/* allocate the blocks.
1581 	 */
1582 	rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1583 	if (rc == -ENOSPC) {
1584 		jfs_error(bmp->db_ipbmap->i_sb,
1585 			  "dbAllocAny: unable to allocate blocks");
1586 		return -EIO;
1587 	}
1588 	return (rc);
1589 }
1590 
1591 
1592 /*
1593  * NAME:	dbFindCtl()
1594  *
1595  * FUNCTION:	starting at a specified dmap control page level and block
1596  *		number, search down the dmap control levels for a range of
1597  *		contiguous free blocks large enough to satisfy an allocation
1598  *		request for the specified number of free blocks.
1599  *
1600  *		if sufficient contiguous free blocks are found, this routine
1601  *		returns the starting block number within a dmap page that
1602  *		contains or starts a range of contiqious free blocks that
1603  *		is sufficient in size.
1604  *
1605  * PARAMETERS:
1606  *	bmp	-  pointer to bmap descriptor
1607  *	level	-  starting dmap control page level.
1608  *	l2nb	-  log2 number of contiguous free blocks desired.
1609  *	*blkno	-  on entry, starting block number for conducting the search.
1610  *		   on successful return, the first block within a dmap page
1611  *		   that contains or starts a range of contiguous free blocks.
1612  *
1613  * RETURN VALUES:
1614  *	0	- success
1615  *	-ENOSPC	- insufficient disk resources
1616  *	-EIO	- i/o error
1617  *
1618  * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1619  */
dbFindCtl(struct bmap * bmp,int l2nb,int level,s64 * blkno)1620 static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno)
1621 {
1622 	int rc, leafidx, lev;
1623 	s64 b, lblkno;
1624 	struct dmapctl *dcp;
1625 	int budmin;
1626 	struct metapage *mp;
1627 
1628 	/* starting at the specified dmap control page level and block
1629 	 * number, search down the dmap control levels for the starting
1630 	 * block number of a dmap page that contains or starts off
1631 	 * sufficient free blocks.
1632 	 */
1633 	for (lev = level, b = *blkno; lev >= 0; lev--) {
1634 		/* get the buffer of the dmap control page for the block
1635 		 * number and level (i.e. L0, L1, L2).
1636 		 */
1637 		lblkno = BLKTOCTL(b, bmp->db_l2nbperpage, lev);
1638 		mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1639 		if (mp == NULL)
1640 			return -EIO;
1641 		dcp = (struct dmapctl *) mp->data;
1642 		budmin = dcp->budmin;
1643 
1644 		if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1645 			jfs_error(bmp->db_ipbmap->i_sb,
1646 				  "dbFindCtl: Corrupt dmapctl page");
1647 			release_metapage(mp);
1648 			return -EIO;
1649 		}
1650 
1651 		/* search the tree within the dmap control page for
1652 		 * sufficient free space.  if sufficient free space is found,
1653 		 * dbFindLeaf() returns the index of the leaf at which
1654 		 * free space was found.
1655 		 */
1656 		rc = dbFindLeaf((dmtree_t *) dcp, l2nb, &leafidx);
1657 
1658 		/* release the buffer.
1659 		 */
1660 		release_metapage(mp);
1661 
1662 		/* space found ?
1663 		 */
1664 		if (rc) {
1665 			if (lev != level) {
1666 				jfs_error(bmp->db_ipbmap->i_sb,
1667 					  "dbFindCtl: dmap inconsistent");
1668 				return -EIO;
1669 			}
1670 			return -ENOSPC;
1671 		}
1672 
1673 		/* adjust the block number to reflect the location within
1674 		 * the dmap control page (i.e. the leaf) at which free
1675 		 * space was found.
1676 		 */
1677 		b += (((s64) leafidx) << budmin);
1678 
1679 		/* we stop the search at this dmap control page level if
1680 		 * the number of blocks required is greater than or equal
1681 		 * to the maximum number of blocks described at the next
1682 		 * (lower) level.
1683 		 */
1684 		if (l2nb >= budmin)
1685 			break;
1686 	}
1687 
1688 	*blkno = b;
1689 	return (0);
1690 }
1691 
1692 
1693 /*
1694  * NAME:	dbAllocCtl()
1695  *
1696  * FUNCTION:	attempt to allocate a specified number of contiguous
1697  *		blocks starting within a specific dmap.
1698  *
1699  *		this routine is called by higher level routines that search
1700  *		the dmap control pages above the actual dmaps for contiguous
1701  *		free space.  the result of successful searches by these
1702  *		routines are the starting block numbers within dmaps, with
1703  *		the dmaps themselves containing the desired contiguous free
1704  *		space or starting a contiguous free space of desired size
1705  *		that is made up of the blocks of one or more dmaps. these
1706  *		calls should not fail due to insufficent resources.
1707  *
1708  *		this routine is called in some cases where it is not known
1709  *		whether it will fail due to insufficient resources.  more
1710  *		specifically, this occurs when allocating from an allocation
1711  *		group whose size is equal to the number of blocks per dmap.
1712  *		in this case, the dmap control pages are not examined prior
1713  *		to calling this routine (to save pathlength) and the call
1714  *		might fail.
1715  *
1716  *		for a request size that fits within a dmap, this routine relies
1717  *		upon the dmap's dmtree to find the requested contiguous free
1718  *		space.  for request sizes that are larger than a dmap, the
1719  *		requested free space will start at the first block of the
1720  *		first dmap (i.e. blkno).
1721  *
1722  * PARAMETERS:
1723  *	bmp	-  pointer to bmap descriptor
1724  *	nblocks	 -  actual number of contiguous free blocks to allocate.
1725  *	l2nb	 -  log2 number of contiguous free blocks to allocate.
1726  *	blkno	 -  starting block number of the dmap to start the allocation
1727  *		    from.
1728  *	results	-  on successful return, set to the starting block number
1729  *		   of the newly allocated range.
1730  *
1731  * RETURN VALUES:
1732  *	0	- success
1733  *	-ENOSPC	- insufficient disk resources
1734  *	-EIO	- i/o error
1735  *
1736  * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1737  */
1738 static int
dbAllocCtl(struct bmap * bmp,s64 nblocks,int l2nb,s64 blkno,s64 * results)1739 dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results)
1740 {
1741 	int rc, nb;
1742 	s64 b, lblkno, n;
1743 	struct metapage *mp;
1744 	struct dmap *dp;
1745 
1746 	/* check if the allocation request is confined to a single dmap.
1747 	 */
1748 	if (l2nb <= L2BPERDMAP) {
1749 		/* get the buffer for the dmap.
1750 		 */
1751 		lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
1752 		mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1753 		if (mp == NULL)
1754 			return -EIO;
1755 		dp = (struct dmap *) mp->data;
1756 
1757 		/* try to allocate the blocks.
1758 		 */
1759 		rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results);
1760 		if (rc == 0)
1761 			mark_metapage_dirty(mp);
1762 
1763 		release_metapage(mp);
1764 
1765 		return (rc);
1766 	}
1767 
1768 	/* allocation request involving multiple dmaps. it must start on
1769 	 * a dmap boundary.
1770 	 */
1771 	assert((blkno & (BPERDMAP - 1)) == 0);
1772 
1773 	/* allocate the blocks dmap by dmap.
1774 	 */
1775 	for (n = nblocks, b = blkno; n > 0; n -= nb, b += nb) {
1776 		/* get the buffer for the dmap.
1777 		 */
1778 		lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1779 		mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1780 		if (mp == NULL) {
1781 			rc = -EIO;
1782 			goto backout;
1783 		}
1784 		dp = (struct dmap *) mp->data;
1785 
1786 		/* the dmap better be all free.
1787 		 */
1788 		if (dp->tree.stree[ROOT] != L2BPERDMAP) {
1789 			release_metapage(mp);
1790 			jfs_error(bmp->db_ipbmap->i_sb,
1791 				  "dbAllocCtl: the dmap is not all free");
1792 			rc = -EIO;
1793 			goto backout;
1794 		}
1795 
1796 		/* determine how many blocks to allocate from this dmap.
1797 		 */
1798 		nb = min(n, (s64)BPERDMAP);
1799 
1800 		/* allocate the blocks from the dmap.
1801 		 */
1802 		if ((rc = dbAllocDmap(bmp, dp, b, nb))) {
1803 			release_metapage(mp);
1804 			goto backout;
1805 		}
1806 
1807 		/* write the buffer.
1808 		 */
1809 		write_metapage(mp);
1810 	}
1811 
1812 	/* set the results (starting block number) and return.
1813 	 */
1814 	*results = blkno;
1815 	return (0);
1816 
1817 	/* something failed in handling an allocation request involving
1818 	 * multiple dmaps.  we'll try to clean up by backing out any
1819 	 * allocation that has already happened for this request.  if
1820 	 * we fail in backing out the allocation, we'll mark the file
1821 	 * system to indicate that blocks have been leaked.
1822 	 */
1823       backout:
1824 
1825 	/* try to backout the allocations dmap by dmap.
1826 	 */
1827 	for (n = nblocks - n, b = blkno; n > 0;
1828 	     n -= BPERDMAP, b += BPERDMAP) {
1829 		/* get the buffer for this dmap.
1830 		 */
1831 		lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1832 		mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1833 		if (mp == NULL) {
1834 			/* could not back out.  mark the file system
1835 			 * to indicate that we have leaked blocks.
1836 			 */
1837 			jfs_error(bmp->db_ipbmap->i_sb,
1838 				  "dbAllocCtl: I/O Error: Block Leakage.");
1839 			continue;
1840 		}
1841 		dp = (struct dmap *) mp->data;
1842 
1843 		/* free the blocks is this dmap.
1844 		 */
1845 		if (dbFreeDmap(bmp, dp, b, BPERDMAP)) {
1846 			/* could not back out.  mark the file system
1847 			 * to indicate that we have leaked blocks.
1848 			 */
1849 			release_metapage(mp);
1850 			jfs_error(bmp->db_ipbmap->i_sb,
1851 				  "dbAllocCtl: Block Leakage.");
1852 			continue;
1853 		}
1854 
1855 		/* write the buffer.
1856 		 */
1857 		write_metapage(mp);
1858 	}
1859 
1860 	return (rc);
1861 }
1862 
1863 
1864 /*
1865  * NAME:	dbAllocDmapLev()
1866  *
1867  * FUNCTION:	attempt to allocate a specified number of contiguous blocks
1868  *		from a specified dmap.
1869  *
1870  *		this routine checks if the contiguous blocks are available.
1871  *		if so, nblocks of blocks are allocated; otherwise, ENOSPC is
1872  *		returned.
1873  *
1874  * PARAMETERS:
1875  *	mp	-  pointer to bmap descriptor
1876  *	dp	-  pointer to dmap to attempt to allocate blocks from.
1877  *	l2nb	-  log2 number of contiguous block desired.
1878  *	nblocks	-  actual number of contiguous block desired.
1879  *	results	-  on successful return, set to the starting block number
1880  *		   of the newly allocated range.
1881  *
1882  * RETURN VALUES:
1883  *	0	- success
1884  *	-ENOSPC	- insufficient disk resources
1885  *	-EIO	- i/o error
1886  *
1887  * serialization: IREAD_LOCK(ipbmap), e.g., from dbAlloc(), or
1888  *	IWRITE_LOCK(ipbmap), e.g., dbAllocCtl(), held on entry/exit;
1889  */
1890 static int
dbAllocDmapLev(struct bmap * bmp,struct dmap * dp,int nblocks,int l2nb,s64 * results)1891 dbAllocDmapLev(struct bmap * bmp,
1892 	       struct dmap * dp, int nblocks, int l2nb, s64 * results)
1893 {
1894 	s64 blkno;
1895 	int leafidx, rc;
1896 
1897 	/* can't be more than a dmaps worth of blocks */
1898 	assert(l2nb <= L2BPERDMAP);
1899 
1900 	/* search the tree within the dmap page for sufficient
1901 	 * free space.  if sufficient free space is found, dbFindLeaf()
1902 	 * returns the index of the leaf at which free space was found.
1903 	 */
1904 	if (dbFindLeaf((dmtree_t *) & dp->tree, l2nb, &leafidx))
1905 		return -ENOSPC;
1906 
1907 	/* determine the block number within the file system corresponding
1908 	 * to the leaf at which free space was found.
1909 	 */
1910 	blkno = le64_to_cpu(dp->start) + (leafidx << L2DBWORD);
1911 
1912 	/* if not all bits of the dmap word are free, get the starting
1913 	 * bit number within the dmap word of the required string of free
1914 	 * bits and adjust the block number with this value.
1915 	 */
1916 	if (dp->tree.stree[leafidx + LEAFIND] < BUDMIN)
1917 		blkno += dbFindBits(le32_to_cpu(dp->wmap[leafidx]), l2nb);
1918 
1919 	/* allocate the blocks */
1920 	if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1921 		*results = blkno;
1922 
1923 	return (rc);
1924 }
1925 
1926 
1927 /*
1928  * NAME:	dbAllocDmap()
1929  *
1930  * FUNCTION:	adjust the disk allocation map to reflect the allocation
1931  *		of a specified block range within a dmap.
1932  *
1933  *		this routine allocates the specified blocks from the dmap
1934  *		through a call to dbAllocBits(). if the allocation of the
1935  *		block range causes the maximum string of free blocks within
1936  *		the dmap to change (i.e. the value of the root of the dmap's
1937  *		dmtree), this routine will cause this change to be reflected
1938  *		up through the appropriate levels of the dmap control pages
1939  *		by a call to dbAdjCtl() for the L0 dmap control page that
1940  *		covers this dmap.
1941  *
1942  * PARAMETERS:
1943  *	bmp	-  pointer to bmap descriptor
1944  *	dp	-  pointer to dmap to allocate the block range from.
1945  *	blkno	-  starting block number of the block to be allocated.
1946  *	nblocks	-  number of blocks to be allocated.
1947  *
1948  * RETURN VALUES:
1949  *	0	- success
1950  *	-EIO	- i/o error
1951  *
1952  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
1953  */
dbAllocDmap(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)1954 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
1955 		       int nblocks)
1956 {
1957 	s8 oldroot;
1958 	int rc;
1959 
1960 	/* save the current value of the root (i.e. maximum free string)
1961 	 * of the dmap tree.
1962 	 */
1963 	oldroot = dp->tree.stree[ROOT];
1964 
1965 	/* allocate the specified (blocks) bits */
1966 	dbAllocBits(bmp, dp, blkno, nblocks);
1967 
1968 	/* if the root has not changed, done. */
1969 	if (dp->tree.stree[ROOT] == oldroot)
1970 		return (0);
1971 
1972 	/* root changed. bubble the change up to the dmap control pages.
1973 	 * if the adjustment of the upper level control pages fails,
1974 	 * backout the bit allocation (thus making everything consistent).
1975 	 */
1976 	if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 1, 0)))
1977 		dbFreeBits(bmp, dp, blkno, nblocks);
1978 
1979 	return (rc);
1980 }
1981 
1982 
1983 /*
1984  * NAME:	dbFreeDmap()
1985  *
1986  * FUNCTION:	adjust the disk allocation map to reflect the allocation
1987  *		of a specified block range within a dmap.
1988  *
1989  *		this routine frees the specified blocks from the dmap through
1990  *		a call to dbFreeBits(). if the deallocation of the block range
1991  *		causes the maximum string of free blocks within the dmap to
1992  *		change (i.e. the value of the root of the dmap's dmtree), this
1993  *		routine will cause this change to be reflected up through the
1994  *		appropriate levels of the dmap control pages by a call to
1995  *		dbAdjCtl() for the L0 dmap control page that covers this dmap.
1996  *
1997  * PARAMETERS:
1998  *	bmp	-  pointer to bmap descriptor
1999  *	dp	-  pointer to dmap to free the block range from.
2000  *	blkno	-  starting block number of the block to be freed.
2001  *	nblocks	-  number of blocks to be freed.
2002  *
2003  * RETURN VALUES:
2004  *	0	- success
2005  *	-EIO	- i/o error
2006  *
2007  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2008  */
dbFreeDmap(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)2009 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
2010 		      int nblocks)
2011 {
2012 	s8 oldroot;
2013 	int rc = 0, word;
2014 
2015 	/* save the current value of the root (i.e. maximum free string)
2016 	 * of the dmap tree.
2017 	 */
2018 	oldroot = dp->tree.stree[ROOT];
2019 
2020 	/* free the specified (blocks) bits */
2021 	rc = dbFreeBits(bmp, dp, blkno, nblocks);
2022 
2023 	/* if error or the root has not changed, done. */
2024 	if (rc || (dp->tree.stree[ROOT] == oldroot))
2025 		return (rc);
2026 
2027 	/* root changed. bubble the change up to the dmap control pages.
2028 	 * if the adjustment of the upper level control pages fails,
2029 	 * backout the deallocation.
2030 	 */
2031 	if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 0, 0))) {
2032 		word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
2033 
2034 		/* as part of backing out the deallocation, we will have
2035 		 * to back split the dmap tree if the deallocation caused
2036 		 * the freed blocks to become part of a larger binary buddy
2037 		 * system.
2038 		 */
2039 		if (dp->tree.stree[word] == NOFREE)
2040 			dbBackSplit((dmtree_t *) & dp->tree, word);
2041 
2042 		dbAllocBits(bmp, dp, blkno, nblocks);
2043 	}
2044 
2045 	return (rc);
2046 }
2047 
2048 
2049 /*
2050  * NAME:	dbAllocBits()
2051  *
2052  * FUNCTION:	allocate a specified block range from a dmap.
2053  *
2054  *		this routine updates the dmap to reflect the working
2055  *		state allocation of the specified block range. it directly
2056  *		updates the bits of the working map and causes the adjustment
2057  *		of the binary buddy system described by the dmap's dmtree
2058  *		leaves to reflect the bits allocated.  it also causes the
2059  *		dmap's dmtree, as a whole, to reflect the allocated range.
2060  *
2061  * PARAMETERS:
2062  *	bmp	-  pointer to bmap descriptor
2063  *	dp	-  pointer to dmap to allocate bits from.
2064  *	blkno	-  starting block number of the bits to be allocated.
2065  *	nblocks	-  number of bits to be allocated.
2066  *
2067  * RETURN VALUES: none
2068  *
2069  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2070  */
dbAllocBits(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)2071 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2072 			int nblocks)
2073 {
2074 	int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2075 	dmtree_t *tp = (dmtree_t *) & dp->tree;
2076 	int size;
2077 	s8 *leaf;
2078 
2079 	/* pick up a pointer to the leaves of the dmap tree */
2080 	leaf = dp->tree.stree + LEAFIND;
2081 
2082 	/* determine the bit number and word within the dmap of the
2083 	 * starting block.
2084 	 */
2085 	dbitno = blkno & (BPERDMAP - 1);
2086 	word = dbitno >> L2DBWORD;
2087 
2088 	/* block range better be within the dmap */
2089 	assert(dbitno + nblocks <= BPERDMAP);
2090 
2091 	/* allocate the bits of the dmap's words corresponding to the block
2092 	 * range. not all bits of the first and last words may be contained
2093 	 * within the block range.  if this is the case, we'll work against
2094 	 * those words (i.e. partial first and/or last) on an individual basis
2095 	 * (a single pass), allocating the bits of interest by hand and
2096 	 * updating the leaf corresponding to the dmap word. a single pass
2097 	 * will be used for all dmap words fully contained within the
2098 	 * specified range.  within this pass, the bits of all fully contained
2099 	 * dmap words will be marked as free in a single shot and the leaves
2100 	 * will be updated. a single leaf may describe the free space of
2101 	 * multiple dmap words, so we may update only a subset of the actual
2102 	 * leaves corresponding to the dmap words of the block range.
2103 	 */
2104 	for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2105 		/* determine the bit number within the word and
2106 		 * the number of bits within the word.
2107 		 */
2108 		wbitno = dbitno & (DBWORD - 1);
2109 		nb = min(rembits, DBWORD - wbitno);
2110 
2111 		/* check if only part of a word is to be allocated.
2112 		 */
2113 		if (nb < DBWORD) {
2114 			/* allocate (set to 1) the appropriate bits within
2115 			 * this dmap word.
2116 			 */
2117 			dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
2118 						      >> wbitno);
2119 
2120 			/* update the leaf for this dmap word. in addition
2121 			 * to setting the leaf value to the binary buddy max
2122 			 * of the updated dmap word, dbSplit() will split
2123 			 * the binary system of the leaves if need be.
2124 			 */
2125 			dbSplit(tp, word, BUDMIN,
2126 				dbMaxBud((u8 *) & dp->wmap[word]));
2127 
2128 			word += 1;
2129 		} else {
2130 			/* one or more dmap words are fully contained
2131 			 * within the block range.  determine how many
2132 			 * words and allocate (set to 1) the bits of these
2133 			 * words.
2134 			 */
2135 			nwords = rembits >> L2DBWORD;
2136 			memset(&dp->wmap[word], (int) ONES, nwords * 4);
2137 
2138 			/* determine how many bits.
2139 			 */
2140 			nb = nwords << L2DBWORD;
2141 
2142 			/* now update the appropriate leaves to reflect
2143 			 * the allocated words.
2144 			 */
2145 			for (; nwords > 0; nwords -= nw) {
2146 				if (leaf[word] < BUDMIN) {
2147 					jfs_error(bmp->db_ipbmap->i_sb,
2148 						  "dbAllocBits: leaf page "
2149 						  "corrupt");
2150 					break;
2151 				}
2152 
2153 				/* determine what the leaf value should be
2154 				 * updated to as the minimum of the l2 number
2155 				 * of bits being allocated and the l2 number
2156 				 * of bits currently described by this leaf.
2157 				 */
2158 				size = min((int)leaf[word], NLSTOL2BSZ(nwords));
2159 
2160 				/* update the leaf to reflect the allocation.
2161 				 * in addition to setting the leaf value to
2162 				 * NOFREE, dbSplit() will split the binary
2163 				 * system of the leaves to reflect the current
2164 				 * allocation (size).
2165 				 */
2166 				dbSplit(tp, word, size, NOFREE);
2167 
2168 				/* get the number of dmap words handled */
2169 				nw = BUDSIZE(size, BUDMIN);
2170 				word += nw;
2171 			}
2172 		}
2173 	}
2174 
2175 	/* update the free count for this dmap */
2176 	le32_add_cpu(&dp->nfree, -nblocks);
2177 
2178 	BMAP_LOCK(bmp);
2179 
2180 	/* if this allocation group is completely free,
2181 	 * update the maximum allocation group number if this allocation
2182 	 * group is the new max.
2183 	 */
2184 	agno = blkno >> bmp->db_agl2size;
2185 	if (agno > bmp->db_maxag)
2186 		bmp->db_maxag = agno;
2187 
2188 	/* update the free count for the allocation group and map */
2189 	bmp->db_agfree[agno] -= nblocks;
2190 	bmp->db_nfree -= nblocks;
2191 
2192 	BMAP_UNLOCK(bmp);
2193 }
2194 
2195 
2196 /*
2197  * NAME:	dbFreeBits()
2198  *
2199  * FUNCTION:	free a specified block range from a dmap.
2200  *
2201  *		this routine updates the dmap to reflect the working
2202  *		state allocation of the specified block range. it directly
2203  *		updates the bits of the working map and causes the adjustment
2204  *		of the binary buddy system described by the dmap's dmtree
2205  *		leaves to reflect the bits freed.  it also causes the dmap's
2206  *		dmtree, as a whole, to reflect the deallocated range.
2207  *
2208  * PARAMETERS:
2209  *	bmp	-  pointer to bmap descriptor
2210  *	dp	-  pointer to dmap to free bits from.
2211  *	blkno	-  starting block number of the bits to be freed.
2212  *	nblocks	-  number of bits to be freed.
2213  *
2214  * RETURN VALUES: 0 for success
2215  *
2216  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2217  */
dbFreeBits(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)2218 static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2219 		       int nblocks)
2220 {
2221 	int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2222 	dmtree_t *tp = (dmtree_t *) & dp->tree;
2223 	int rc = 0;
2224 	int size;
2225 
2226 	/* determine the bit number and word within the dmap of the
2227 	 * starting block.
2228 	 */
2229 	dbitno = blkno & (BPERDMAP - 1);
2230 	word = dbitno >> L2DBWORD;
2231 
2232 	/* block range better be within the dmap.
2233 	 */
2234 	assert(dbitno + nblocks <= BPERDMAP);
2235 
2236 	/* free the bits of the dmaps words corresponding to the block range.
2237 	 * not all bits of the first and last words may be contained within
2238 	 * the block range.  if this is the case, we'll work against those
2239 	 * words (i.e. partial first and/or last) on an individual basis
2240 	 * (a single pass), freeing the bits of interest by hand and updating
2241 	 * the leaf corresponding to the dmap word. a single pass will be used
2242 	 * for all dmap words fully contained within the specified range.
2243 	 * within this pass, the bits of all fully contained dmap words will
2244 	 * be marked as free in a single shot and the leaves will be updated. a
2245 	 * single leaf may describe the free space of multiple dmap words,
2246 	 * so we may update only a subset of the actual leaves corresponding
2247 	 * to the dmap words of the block range.
2248 	 *
2249 	 * dbJoin() is used to update leaf values and will join the binary
2250 	 * buddy system of the leaves if the new leaf values indicate this
2251 	 * should be done.
2252 	 */
2253 	for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2254 		/* determine the bit number within the word and
2255 		 * the number of bits within the word.
2256 		 */
2257 		wbitno = dbitno & (DBWORD - 1);
2258 		nb = min(rembits, DBWORD - wbitno);
2259 
2260 		/* check if only part of a word is to be freed.
2261 		 */
2262 		if (nb < DBWORD) {
2263 			/* free (zero) the appropriate bits within this
2264 			 * dmap word.
2265 			 */
2266 			dp->wmap[word] &=
2267 			    cpu_to_le32(~(ONES << (DBWORD - nb)
2268 					  >> wbitno));
2269 
2270 			/* update the leaf for this dmap word.
2271 			 */
2272 			rc = dbJoin(tp, word,
2273 				    dbMaxBud((u8 *) & dp->wmap[word]));
2274 			if (rc)
2275 				return rc;
2276 
2277 			word += 1;
2278 		} else {
2279 			/* one or more dmap words are fully contained
2280 			 * within the block range.  determine how many
2281 			 * words and free (zero) the bits of these words.
2282 			 */
2283 			nwords = rembits >> L2DBWORD;
2284 			memset(&dp->wmap[word], 0, nwords * 4);
2285 
2286 			/* determine how many bits.
2287 			 */
2288 			nb = nwords << L2DBWORD;
2289 
2290 			/* now update the appropriate leaves to reflect
2291 			 * the freed words.
2292 			 */
2293 			for (; nwords > 0; nwords -= nw) {
2294 				/* determine what the leaf value should be
2295 				 * updated to as the minimum of the l2 number
2296 				 * of bits being freed and the l2 (max) number
2297 				 * of bits that can be described by this leaf.
2298 				 */
2299 				size =
2300 				    min(LITOL2BSZ
2301 					(word, L2LPERDMAP, BUDMIN),
2302 					NLSTOL2BSZ(nwords));
2303 
2304 				/* update the leaf.
2305 				 */
2306 				rc = dbJoin(tp, word, size);
2307 				if (rc)
2308 					return rc;
2309 
2310 				/* get the number of dmap words handled.
2311 				 */
2312 				nw = BUDSIZE(size, BUDMIN);
2313 				word += nw;
2314 			}
2315 		}
2316 	}
2317 
2318 	/* update the free count for this dmap.
2319 	 */
2320 	le32_add_cpu(&dp->nfree, nblocks);
2321 
2322 	BMAP_LOCK(bmp);
2323 
2324 	/* update the free count for the allocation group and
2325 	 * map.
2326 	 */
2327 	agno = blkno >> bmp->db_agl2size;
2328 	bmp->db_nfree += nblocks;
2329 	bmp->db_agfree[agno] += nblocks;
2330 
2331 	/* check if this allocation group is not completely free and
2332 	 * if it is currently the maximum (rightmost) allocation group.
2333 	 * if so, establish the new maximum allocation group number by
2334 	 * searching left for the first allocation group with allocation.
2335 	 */
2336 	if ((bmp->db_agfree[agno] == bmp->db_agsize && agno == bmp->db_maxag) ||
2337 	    (agno == bmp->db_numag - 1 &&
2338 	     bmp->db_agfree[agno] == (bmp-> db_mapsize & (BPERDMAP - 1)))) {
2339 		while (bmp->db_maxag > 0) {
2340 			bmp->db_maxag -= 1;
2341 			if (bmp->db_agfree[bmp->db_maxag] !=
2342 			    bmp->db_agsize)
2343 				break;
2344 		}
2345 
2346 		/* re-establish the allocation group preference if the
2347 		 * current preference is right of the maximum allocation
2348 		 * group.
2349 		 */
2350 		if (bmp->db_agpref > bmp->db_maxag)
2351 			bmp->db_agpref = bmp->db_maxag;
2352 	}
2353 
2354 	BMAP_UNLOCK(bmp);
2355 
2356 	return 0;
2357 }
2358 
2359 
2360 /*
2361  * NAME:	dbAdjCtl()
2362  *
2363  * FUNCTION:	adjust a dmap control page at a specified level to reflect
2364  *		the change in a lower level dmap or dmap control page's
2365  *		maximum string of free blocks (i.e. a change in the root
2366  *		of the lower level object's dmtree) due to the allocation
2367  *		or deallocation of a range of blocks with a single dmap.
2368  *
2369  *		on entry, this routine is provided with the new value of
2370  *		the lower level dmap or dmap control page root and the
2371  *		starting block number of the block range whose allocation
2372  *		or deallocation resulted in the root change.  this range
2373  *		is respresented by a single leaf of the current dmapctl
2374  *		and the leaf will be updated with this value, possibly
2375  *		causing a binary buddy system within the leaves to be
2376  *		split or joined.  the update may also cause the dmapctl's
2377  *		dmtree to be updated.
2378  *
2379  *		if the adjustment of the dmap control page, itself, causes its
2380  *		root to change, this change will be bubbled up to the next dmap
2381  *		control level by a recursive call to this routine, specifying
2382  *		the new root value and the next dmap control page level to
2383  *		be adjusted.
2384  * PARAMETERS:
2385  *	bmp	-  pointer to bmap descriptor
2386  *	blkno	-  the first block of a block range within a dmap.  it is
2387  *		   the allocation or deallocation of this block range that
2388  *		   requires the dmap control page to be adjusted.
2389  *	newval	-  the new value of the lower level dmap or dmap control
2390  *		   page root.
2391  *	alloc	-  'true' if adjustment is due to an allocation.
2392  *	level	-  current level of dmap control page (i.e. L0, L1, L2) to
2393  *		   be adjusted.
2394  *
2395  * RETURN VALUES:
2396  *	0	- success
2397  *	-EIO	- i/o error
2398  *
2399  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2400  */
2401 static int
dbAdjCtl(struct bmap * bmp,s64 blkno,int newval,int alloc,int level)2402 dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, int level)
2403 {
2404 	struct metapage *mp;
2405 	s8 oldroot;
2406 	int oldval;
2407 	s64 lblkno;
2408 	struct dmapctl *dcp;
2409 	int rc, leafno, ti;
2410 
2411 	/* get the buffer for the dmap control page for the specified
2412 	 * block number and control page level.
2413 	 */
2414 	lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, level);
2415 	mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
2416 	if (mp == NULL)
2417 		return -EIO;
2418 	dcp = (struct dmapctl *) mp->data;
2419 
2420 	if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
2421 		jfs_error(bmp->db_ipbmap->i_sb,
2422 			  "dbAdjCtl: Corrupt dmapctl page");
2423 		release_metapage(mp);
2424 		return -EIO;
2425 	}
2426 
2427 	/* determine the leaf number corresponding to the block and
2428 	 * the index within the dmap control tree.
2429 	 */
2430 	leafno = BLKTOCTLLEAF(blkno, dcp->budmin);
2431 	ti = leafno + le32_to_cpu(dcp->leafidx);
2432 
2433 	/* save the current leaf value and the current root level (i.e.
2434 	 * maximum l2 free string described by this dmapctl).
2435 	 */
2436 	oldval = dcp->stree[ti];
2437 	oldroot = dcp->stree[ROOT];
2438 
2439 	/* check if this is a control page update for an allocation.
2440 	 * if so, update the leaf to reflect the new leaf value using
2441 	 * dbSplit(); otherwise (deallocation), use dbJoin() to update
2442 	 * the leaf with the new value.  in addition to updating the
2443 	 * leaf, dbSplit() will also split the binary buddy system of
2444 	 * the leaves, if required, and bubble new values within the
2445 	 * dmapctl tree, if required.  similarly, dbJoin() will join
2446 	 * the binary buddy system of leaves and bubble new values up
2447 	 * the dmapctl tree as required by the new leaf value.
2448 	 */
2449 	if (alloc) {
2450 		/* check if we are in the middle of a binary buddy
2451 		 * system.  this happens when we are performing the
2452 		 * first allocation out of an allocation group that
2453 		 * is part (not the first part) of a larger binary
2454 		 * buddy system.  if we are in the middle, back split
2455 		 * the system prior to calling dbSplit() which assumes
2456 		 * that it is at the front of a binary buddy system.
2457 		 */
2458 		if (oldval == NOFREE) {
2459 			rc = dbBackSplit((dmtree_t *) dcp, leafno);
2460 			if (rc)
2461 				return rc;
2462 			oldval = dcp->stree[ti];
2463 		}
2464 		dbSplit((dmtree_t *) dcp, leafno, dcp->budmin, newval);
2465 	} else {
2466 		rc = dbJoin((dmtree_t *) dcp, leafno, newval);
2467 		if (rc)
2468 			return rc;
2469 	}
2470 
2471 	/* check if the root of the current dmap control page changed due
2472 	 * to the update and if the current dmap control page is not at
2473 	 * the current top level (i.e. L0, L1, L2) of the map.  if so (i.e.
2474 	 * root changed and this is not the top level), call this routine
2475 	 * again (recursion) for the next higher level of the mapping to
2476 	 * reflect the change in root for the current dmap control page.
2477 	 */
2478 	if (dcp->stree[ROOT] != oldroot) {
2479 		/* are we below the top level of the map.  if so,
2480 		 * bubble the root up to the next higher level.
2481 		 */
2482 		if (level < bmp->db_maxlevel) {
2483 			/* bubble up the new root of this dmap control page to
2484 			 * the next level.
2485 			 */
2486 			if ((rc =
2487 			     dbAdjCtl(bmp, blkno, dcp->stree[ROOT], alloc,
2488 				      level + 1))) {
2489 				/* something went wrong in bubbling up the new
2490 				 * root value, so backout the changes to the
2491 				 * current dmap control page.
2492 				 */
2493 				if (alloc) {
2494 					dbJoin((dmtree_t *) dcp, leafno,
2495 					       oldval);
2496 				} else {
2497 					/* the dbJoin() above might have
2498 					 * caused a larger binary buddy system
2499 					 * to form and we may now be in the
2500 					 * middle of it.  if this is the case,
2501 					 * back split the buddies.
2502 					 */
2503 					if (dcp->stree[ti] == NOFREE)
2504 						dbBackSplit((dmtree_t *)
2505 							    dcp, leafno);
2506 					dbSplit((dmtree_t *) dcp, leafno,
2507 						dcp->budmin, oldval);
2508 				}
2509 
2510 				/* release the buffer and return the error.
2511 				 */
2512 				release_metapage(mp);
2513 				return (rc);
2514 			}
2515 		} else {
2516 			/* we're at the top level of the map. update
2517 			 * the bmap control page to reflect the size
2518 			 * of the maximum free buddy system.
2519 			 */
2520 			assert(level == bmp->db_maxlevel);
2521 			if (bmp->db_maxfreebud != oldroot) {
2522 				jfs_error(bmp->db_ipbmap->i_sb,
2523 					  "dbAdjCtl: the maximum free buddy is "
2524 					  "not the old root");
2525 			}
2526 			bmp->db_maxfreebud = dcp->stree[ROOT];
2527 		}
2528 	}
2529 
2530 	/* write the buffer.
2531 	 */
2532 	write_metapage(mp);
2533 
2534 	return (0);
2535 }
2536 
2537 
2538 /*
2539  * NAME:	dbSplit()
2540  *
2541  * FUNCTION:	update the leaf of a dmtree with a new value, splitting
2542  *		the leaf from the binary buddy system of the dmtree's
2543  *		leaves, as required.
2544  *
2545  * PARAMETERS:
2546  *	tp	- pointer to the tree containing the leaf.
2547  *	leafno	- the number of the leaf to be updated.
2548  *	splitsz	- the size the binary buddy system starting at the leaf
2549  *		  must be split to, specified as the log2 number of blocks.
2550  *	newval	- the new value for the leaf.
2551  *
2552  * RETURN VALUES: none
2553  *
2554  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2555  */
dbSplit(dmtree_t * tp,int leafno,int splitsz,int newval)2556 static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval)
2557 {
2558 	int budsz;
2559 	int cursz;
2560 	s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2561 
2562 	/* check if the leaf needs to be split.
2563 	 */
2564 	if (leaf[leafno] > tp->dmt_budmin) {
2565 		/* the split occurs by cutting the buddy system in half
2566 		 * at the specified leaf until we reach the specified
2567 		 * size.  pick up the starting split size (current size
2568 		 * - 1 in l2) and the corresponding buddy size.
2569 		 */
2570 		cursz = leaf[leafno] - 1;
2571 		budsz = BUDSIZE(cursz, tp->dmt_budmin);
2572 
2573 		/* split until we reach the specified size.
2574 		 */
2575 		while (cursz >= splitsz) {
2576 			/* update the buddy's leaf with its new value.
2577 			 */
2578 			dbAdjTree(tp, leafno ^ budsz, cursz);
2579 
2580 			/* on to the next size and buddy.
2581 			 */
2582 			cursz -= 1;
2583 			budsz >>= 1;
2584 		}
2585 	}
2586 
2587 	/* adjust the dmap tree to reflect the specified leaf's new
2588 	 * value.
2589 	 */
2590 	dbAdjTree(tp, leafno, newval);
2591 }
2592 
2593 
2594 /*
2595  * NAME:	dbBackSplit()
2596  *
2597  * FUNCTION:	back split the binary buddy system of dmtree leaves
2598  *		that hold a specified leaf until the specified leaf
2599  *		starts its own binary buddy system.
2600  *
2601  *		the allocators typically perform allocations at the start
2602  *		of binary buddy systems and dbSplit() is used to accomplish
2603  *		any required splits.  in some cases, however, allocation
2604  *		may occur in the middle of a binary system and requires a
2605  *		back split, with the split proceeding out from the middle of
2606  *		the system (less efficient) rather than the start of the
2607  *		system (more efficient).  the cases in which a back split
2608  *		is required are rare and are limited to the first allocation
2609  *		within an allocation group which is a part (not first part)
2610  *		of a larger binary buddy system and a few exception cases
2611  *		in which a previous join operation must be backed out.
2612  *
2613  * PARAMETERS:
2614  *	tp	- pointer to the tree containing the leaf.
2615  *	leafno	- the number of the leaf to be updated.
2616  *
2617  * RETURN VALUES: none
2618  *
2619  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2620  */
dbBackSplit(dmtree_t * tp,int leafno)2621 static int dbBackSplit(dmtree_t * tp, int leafno)
2622 {
2623 	int budsz, bud, w, bsz, size;
2624 	int cursz;
2625 	s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2626 
2627 	/* leaf should be part (not first part) of a binary
2628 	 * buddy system.
2629 	 */
2630 	assert(leaf[leafno] == NOFREE);
2631 
2632 	/* the back split is accomplished by iteratively finding the leaf
2633 	 * that starts the buddy system that contains the specified leaf and
2634 	 * splitting that system in two.  this iteration continues until
2635 	 * the specified leaf becomes the start of a buddy system.
2636 	 *
2637 	 * determine maximum possible l2 size for the specified leaf.
2638 	 */
2639 	size =
2640 	    LITOL2BSZ(leafno, le32_to_cpu(tp->dmt_l2nleafs),
2641 		      tp->dmt_budmin);
2642 
2643 	/* determine the number of leaves covered by this size.  this
2644 	 * is the buddy size that we will start with as we search for
2645 	 * the buddy system that contains the specified leaf.
2646 	 */
2647 	budsz = BUDSIZE(size, tp->dmt_budmin);
2648 
2649 	/* back split.
2650 	 */
2651 	while (leaf[leafno] == NOFREE) {
2652 		/* find the leftmost buddy leaf.
2653 		 */
2654 		for (w = leafno, bsz = budsz;; bsz <<= 1,
2655 		     w = (w < bud) ? w : bud) {
2656 			if (bsz >= le32_to_cpu(tp->dmt_nleafs)) {
2657 				jfs_err("JFS: block map error in dbBackSplit");
2658 				return -EIO;
2659 			}
2660 
2661 			/* determine the buddy.
2662 			 */
2663 			bud = w ^ bsz;
2664 
2665 			/* check if this buddy is the start of the system.
2666 			 */
2667 			if (leaf[bud] != NOFREE) {
2668 				/* split the leaf at the start of the
2669 				 * system in two.
2670 				 */
2671 				cursz = leaf[bud] - 1;
2672 				dbSplit(tp, bud, cursz, cursz);
2673 				break;
2674 			}
2675 		}
2676 	}
2677 
2678 	if (leaf[leafno] != size) {
2679 		jfs_err("JFS: wrong leaf value in dbBackSplit");
2680 		return -EIO;
2681 	}
2682 	return 0;
2683 }
2684 
2685 
2686 /*
2687  * NAME:	dbJoin()
2688  *
2689  * FUNCTION:	update the leaf of a dmtree with a new value, joining
2690  *		the leaf with other leaves of the dmtree into a multi-leaf
2691  *		binary buddy system, as required.
2692  *
2693  * PARAMETERS:
2694  *	tp	- pointer to the tree containing the leaf.
2695  *	leafno	- the number of the leaf to be updated.
2696  *	newval	- the new value for the leaf.
2697  *
2698  * RETURN VALUES: none
2699  */
dbJoin(dmtree_t * tp,int leafno,int newval)2700 static int dbJoin(dmtree_t * tp, int leafno, int newval)
2701 {
2702 	int budsz, buddy;
2703 	s8 *leaf;
2704 
2705 	/* can the new leaf value require a join with other leaves ?
2706 	 */
2707 	if (newval >= tp->dmt_budmin) {
2708 		/* pickup a pointer to the leaves of the tree.
2709 		 */
2710 		leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2711 
2712 		/* try to join the specified leaf into a large binary
2713 		 * buddy system.  the join proceeds by attempting to join
2714 		 * the specified leafno with its buddy (leaf) at new value.
2715 		 * if the join occurs, we attempt to join the left leaf
2716 		 * of the joined buddies with its buddy at new value + 1.
2717 		 * we continue to join until we find a buddy that cannot be
2718 		 * joined (does not have a value equal to the size of the
2719 		 * last join) or until all leaves have been joined into a
2720 		 * single system.
2721 		 *
2722 		 * get the buddy size (number of words covered) of
2723 		 * the new value.
2724 		 */
2725 		budsz = BUDSIZE(newval, tp->dmt_budmin);
2726 
2727 		/* try to join.
2728 		 */
2729 		while (budsz < le32_to_cpu(tp->dmt_nleafs)) {
2730 			/* get the buddy leaf.
2731 			 */
2732 			buddy = leafno ^ budsz;
2733 
2734 			/* if the leaf's new value is greater than its
2735 			 * buddy's value, we join no more.
2736 			 */
2737 			if (newval > leaf[buddy])
2738 				break;
2739 
2740 			/* It shouldn't be less */
2741 			if (newval < leaf[buddy])
2742 				return -EIO;
2743 
2744 			/* check which (leafno or buddy) is the left buddy.
2745 			 * the left buddy gets to claim the blocks resulting
2746 			 * from the join while the right gets to claim none.
2747 			 * the left buddy is also eligible to participate in
2748 			 * a join at the next higher level while the right
2749 			 * is not.
2750 			 *
2751 			 */
2752 			if (leafno < buddy) {
2753 				/* leafno is the left buddy.
2754 				 */
2755 				dbAdjTree(tp, buddy, NOFREE);
2756 			} else {
2757 				/* buddy is the left buddy and becomes
2758 				 * leafno.
2759 				 */
2760 				dbAdjTree(tp, leafno, NOFREE);
2761 				leafno = buddy;
2762 			}
2763 
2764 			/* on to try the next join.
2765 			 */
2766 			newval += 1;
2767 			budsz <<= 1;
2768 		}
2769 	}
2770 
2771 	/* update the leaf value.
2772 	 */
2773 	dbAdjTree(tp, leafno, newval);
2774 
2775 	return 0;
2776 }
2777 
2778 
2779 /*
2780  * NAME:	dbAdjTree()
2781  *
2782  * FUNCTION:	update a leaf of a dmtree with a new value, adjusting
2783  *		the dmtree, as required, to reflect the new leaf value.
2784  *		the combination of any buddies must already be done before
2785  *		this is called.
2786  *
2787  * PARAMETERS:
2788  *	tp	- pointer to the tree to be adjusted.
2789  *	leafno	- the number of the leaf to be updated.
2790  *	newval	- the new value for the leaf.
2791  *
2792  * RETURN VALUES: none
2793  */
dbAdjTree(dmtree_t * tp,int leafno,int newval)2794 static void dbAdjTree(dmtree_t * tp, int leafno, int newval)
2795 {
2796 	int lp, pp, k;
2797 	int max;
2798 
2799 	/* pick up the index of the leaf for this leafno.
2800 	 */
2801 	lp = leafno + le32_to_cpu(tp->dmt_leafidx);
2802 
2803 	/* is the current value the same as the old value ?  if so,
2804 	 * there is nothing to do.
2805 	 */
2806 	if (tp->dmt_stree[lp] == newval)
2807 		return;
2808 
2809 	/* set the new value.
2810 	 */
2811 	tp->dmt_stree[lp] = newval;
2812 
2813 	/* bubble the new value up the tree as required.
2814 	 */
2815 	for (k = 0; k < le32_to_cpu(tp->dmt_height); k++) {
2816 		/* get the index of the first leaf of the 4 leaf
2817 		 * group containing the specified leaf (leafno).
2818 		 */
2819 		lp = ((lp - 1) & ~0x03) + 1;
2820 
2821 		/* get the index of the parent of this 4 leaf group.
2822 		 */
2823 		pp = (lp - 1) >> 2;
2824 
2825 		/* determine the maximum of the 4 leaves.
2826 		 */
2827 		max = TREEMAX(&tp->dmt_stree[lp]);
2828 
2829 		/* if the maximum of the 4 is the same as the
2830 		 * parent's value, we're done.
2831 		 */
2832 		if (tp->dmt_stree[pp] == max)
2833 			break;
2834 
2835 		/* parent gets new value.
2836 		 */
2837 		tp->dmt_stree[pp] = max;
2838 
2839 		/* parent becomes leaf for next go-round.
2840 		 */
2841 		lp = pp;
2842 	}
2843 }
2844 
2845 
2846 /*
2847  * NAME:	dbFindLeaf()
2848  *
2849  * FUNCTION:	search a dmtree_t for sufficient free blocks, returning
2850  *		the index of a leaf describing the free blocks if
2851  *		sufficient free blocks are found.
2852  *
2853  *		the search starts at the top of the dmtree_t tree and
2854  *		proceeds down the tree to the leftmost leaf with sufficient
2855  *		free space.
2856  *
2857  * PARAMETERS:
2858  *	tp	- pointer to the tree to be searched.
2859  *	l2nb	- log2 number of free blocks to search for.
2860  *	leafidx	- return pointer to be set to the index of the leaf
2861  *		  describing at least l2nb free blocks if sufficient
2862  *		  free blocks are found.
2863  *
2864  * RETURN VALUES:
2865  *	0	- success
2866  *	-ENOSPC	- insufficient free blocks.
2867  */
dbFindLeaf(dmtree_t * tp,int l2nb,int * leafidx)2868 static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx)
2869 {
2870 	int ti, n = 0, k, x = 0;
2871 
2872 	/* first check the root of the tree to see if there is
2873 	 * sufficient free space.
2874 	 */
2875 	if (l2nb > tp->dmt_stree[ROOT])
2876 		return -ENOSPC;
2877 
2878 	/* sufficient free space available. now search down the tree
2879 	 * starting at the next level for the leftmost leaf that
2880 	 * describes sufficient free space.
2881 	 */
2882 	for (k = le32_to_cpu(tp->dmt_height), ti = 1;
2883 	     k > 0; k--, ti = ((ti + n) << 2) + 1) {
2884 		/* search the four nodes at this level, starting from
2885 		 * the left.
2886 		 */
2887 		for (x = ti, n = 0; n < 4; n++) {
2888 			/* sufficient free space found.  move to the next
2889 			 * level (or quit if this is the last level).
2890 			 */
2891 			if (l2nb <= tp->dmt_stree[x + n])
2892 				break;
2893 		}
2894 
2895 		/* better have found something since the higher
2896 		 * levels of the tree said it was here.
2897 		 */
2898 		assert(n < 4);
2899 	}
2900 
2901 	/* set the return to the leftmost leaf describing sufficient
2902 	 * free space.
2903 	 */
2904 	*leafidx = x + n - le32_to_cpu(tp->dmt_leafidx);
2905 
2906 	return (0);
2907 }
2908 
2909 
2910 /*
2911  * NAME:	dbFindBits()
2912  *
2913  * FUNCTION:	find a specified number of binary buddy free bits within a
2914  *		dmap bitmap word value.
2915  *
2916  *		this routine searches the bitmap value for (1 << l2nb) free
2917  *		bits at (1 << l2nb) alignments within the value.
2918  *
2919  * PARAMETERS:
2920  *	word	-  dmap bitmap word value.
2921  *	l2nb	-  number of free bits specified as a log2 number.
2922  *
2923  * RETURN VALUES:
2924  *	starting bit number of free bits.
2925  */
dbFindBits(u32 word,int l2nb)2926 static int dbFindBits(u32 word, int l2nb)
2927 {
2928 	int bitno, nb;
2929 	u32 mask;
2930 
2931 	/* get the number of bits.
2932 	 */
2933 	nb = 1 << l2nb;
2934 	assert(nb <= DBWORD);
2935 
2936 	/* complement the word so we can use a mask (i.e. 0s represent
2937 	 * free bits) and compute the mask.
2938 	 */
2939 	word = ~word;
2940 	mask = ONES << (DBWORD - nb);
2941 
2942 	/* scan the word for nb free bits at nb alignments.
2943 	 */
2944 	for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) {
2945 		if ((mask & word) == mask)
2946 			break;
2947 	}
2948 
2949 	ASSERT(bitno < 32);
2950 
2951 	/* return the bit number.
2952 	 */
2953 	return (bitno);
2954 }
2955 
2956 
2957 /*
2958  * NAME:	dbMaxBud(u8 *cp)
2959  *
2960  * FUNCTION:	determine the largest binary buddy string of free
2961  *		bits within 32-bits of the map.
2962  *
2963  * PARAMETERS:
2964  *	cp	-  pointer to the 32-bit value.
2965  *
2966  * RETURN VALUES:
2967  *	largest binary buddy of free bits within a dmap word.
2968  */
dbMaxBud(u8 * cp)2969 static int dbMaxBud(u8 * cp)
2970 {
2971 	signed char tmp1, tmp2;
2972 
2973 	/* check if the wmap word is all free. if so, the
2974 	 * free buddy size is BUDMIN.
2975 	 */
2976 	if (*((uint *) cp) == 0)
2977 		return (BUDMIN);
2978 
2979 	/* check if the wmap word is half free. if so, the
2980 	 * free buddy size is BUDMIN-1.
2981 	 */
2982 	if (*((u16 *) cp) == 0 || *((u16 *) cp + 1) == 0)
2983 		return (BUDMIN - 1);
2984 
2985 	/* not all free or half free. determine the free buddy
2986 	 * size thru table lookup using quarters of the wmap word.
2987 	 */
2988 	tmp1 = max(budtab[cp[2]], budtab[cp[3]]);
2989 	tmp2 = max(budtab[cp[0]], budtab[cp[1]]);
2990 	return (max(tmp1, tmp2));
2991 }
2992 
2993 
2994 /*
2995  * NAME:	cnttz(uint word)
2996  *
2997  * FUNCTION:	determine the number of trailing zeros within a 32-bit
2998  *		value.
2999  *
3000  * PARAMETERS:
3001  *	value	-  32-bit value to be examined.
3002  *
3003  * RETURN VALUES:
3004  *	count of trailing zeros
3005  */
cnttz(u32 word)3006 static int cnttz(u32 word)
3007 {
3008 	int n;
3009 
3010 	for (n = 0; n < 32; n++, word >>= 1) {
3011 		if (word & 0x01)
3012 			break;
3013 	}
3014 
3015 	return (n);
3016 }
3017 
3018 
3019 /*
3020  * NAME:	cntlz(u32 value)
3021  *
3022  * FUNCTION:	determine the number of leading zeros within a 32-bit
3023  *		value.
3024  *
3025  * PARAMETERS:
3026  *	value	-  32-bit value to be examined.
3027  *
3028  * RETURN VALUES:
3029  *	count of leading zeros
3030  */
cntlz(u32 value)3031 static int cntlz(u32 value)
3032 {
3033 	int n;
3034 
3035 	for (n = 0; n < 32; n++, value <<= 1) {
3036 		if (value & HIGHORDER)
3037 			break;
3038 	}
3039 	return (n);
3040 }
3041 
3042 
3043 /*
3044  * NAME:	blkstol2(s64 nb)
3045  *
3046  * FUNCTION:	convert a block count to its log2 value. if the block
3047  *		count is not a l2 multiple, it is rounded up to the next
3048  *		larger l2 multiple.
3049  *
3050  * PARAMETERS:
3051  *	nb	-  number of blocks
3052  *
3053  * RETURN VALUES:
3054  *	log2 number of blocks
3055  */
blkstol2(s64 nb)3056 static int blkstol2(s64 nb)
3057 {
3058 	int l2nb;
3059 	s64 mask;		/* meant to be signed */
3060 
3061 	mask = (s64) 1 << (64 - 1);
3062 
3063 	/* count the leading bits.
3064 	 */
3065 	for (l2nb = 0; l2nb < 64; l2nb++, mask >>= 1) {
3066 		/* leading bit found.
3067 		 */
3068 		if (nb & mask) {
3069 			/* determine the l2 value.
3070 			 */
3071 			l2nb = (64 - 1) - l2nb;
3072 
3073 			/* check if we need to round up.
3074 			 */
3075 			if (~mask & nb)
3076 				l2nb++;
3077 
3078 			return (l2nb);
3079 		}
3080 	}
3081 	assert(0);
3082 	return 0;		/* fix compiler warning */
3083 }
3084 
3085 
3086 /*
3087  * NAME:	dbAllocBottomUp()
3088  *
3089  * FUNCTION:	alloc the specified block range from the working block
3090  *		allocation map.
3091  *
3092  *		the blocks will be alloc from the working map one dmap
3093  *		at a time.
3094  *
3095  * PARAMETERS:
3096  *	ip	-  pointer to in-core inode;
3097  *	blkno	-  starting block number to be freed.
3098  *	nblocks	-  number of blocks to be freed.
3099  *
3100  * RETURN VALUES:
3101  *	0	- success
3102  *	-EIO	- i/o error
3103  */
dbAllocBottomUp(struct inode * ip,s64 blkno,s64 nblocks)3104 int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks)
3105 {
3106 	struct metapage *mp;
3107 	struct dmap *dp;
3108 	int nb, rc;
3109 	s64 lblkno, rem;
3110 	struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
3111 	struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
3112 
3113 	IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
3114 
3115 	/* block to be allocated better be within the mapsize. */
3116 	ASSERT(nblocks <= bmp->db_mapsize - blkno);
3117 
3118 	/*
3119 	 * allocate the blocks a dmap at a time.
3120 	 */
3121 	mp = NULL;
3122 	for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
3123 		/* release previous dmap if any */
3124 		if (mp) {
3125 			write_metapage(mp);
3126 		}
3127 
3128 		/* get the buffer for the current dmap. */
3129 		lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
3130 		mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
3131 		if (mp == NULL) {
3132 			IREAD_UNLOCK(ipbmap);
3133 			return -EIO;
3134 		}
3135 		dp = (struct dmap *) mp->data;
3136 
3137 		/* determine the number of blocks to be allocated from
3138 		 * this dmap.
3139 		 */
3140 		nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
3141 
3142 		/* allocate the blocks. */
3143 		if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) {
3144 			release_metapage(mp);
3145 			IREAD_UNLOCK(ipbmap);
3146 			return (rc);
3147 		}
3148 	}
3149 
3150 	/* write the last buffer. */
3151 	write_metapage(mp);
3152 
3153 	IREAD_UNLOCK(ipbmap);
3154 
3155 	return (0);
3156 }
3157 
3158 
dbAllocDmapBU(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)3159 static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
3160 			 int nblocks)
3161 {
3162 	int rc;
3163 	int dbitno, word, rembits, nb, nwords, wbitno, agno;
3164 	s8 oldroot;
3165 	struct dmaptree *tp = (struct dmaptree *) & dp->tree;
3166 
3167 	/* save the current value of the root (i.e. maximum free string)
3168 	 * of the dmap tree.
3169 	 */
3170 	oldroot = tp->stree[ROOT];
3171 
3172 	/* determine the bit number and word within the dmap of the
3173 	 * starting block.
3174 	 */
3175 	dbitno = blkno & (BPERDMAP - 1);
3176 	word = dbitno >> L2DBWORD;
3177 
3178 	/* block range better be within the dmap */
3179 	assert(dbitno + nblocks <= BPERDMAP);
3180 
3181 	/* allocate the bits of the dmap's words corresponding to the block
3182 	 * range. not all bits of the first and last words may be contained
3183 	 * within the block range.  if this is the case, we'll work against
3184 	 * those words (i.e. partial first and/or last) on an individual basis
3185 	 * (a single pass), allocating the bits of interest by hand and
3186 	 * updating the leaf corresponding to the dmap word. a single pass
3187 	 * will be used for all dmap words fully contained within the
3188 	 * specified range.  within this pass, the bits of all fully contained
3189 	 * dmap words will be marked as free in a single shot and the leaves
3190 	 * will be updated. a single leaf may describe the free space of
3191 	 * multiple dmap words, so we may update only a subset of the actual
3192 	 * leaves corresponding to the dmap words of the block range.
3193 	 */
3194 	for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
3195 		/* determine the bit number within the word and
3196 		 * the number of bits within the word.
3197 		 */
3198 		wbitno = dbitno & (DBWORD - 1);
3199 		nb = min(rembits, DBWORD - wbitno);
3200 
3201 		/* check if only part of a word is to be allocated.
3202 		 */
3203 		if (nb < DBWORD) {
3204 			/* allocate (set to 1) the appropriate bits within
3205 			 * this dmap word.
3206 			 */
3207 			dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
3208 						      >> wbitno);
3209 
3210 			word++;
3211 		} else {
3212 			/* one or more dmap words are fully contained
3213 			 * within the block range.  determine how many
3214 			 * words and allocate (set to 1) the bits of these
3215 			 * words.
3216 			 */
3217 			nwords = rembits >> L2DBWORD;
3218 			memset(&dp->wmap[word], (int) ONES, nwords * 4);
3219 
3220 			/* determine how many bits */
3221 			nb = nwords << L2DBWORD;
3222 			word += nwords;
3223 		}
3224 	}
3225 
3226 	/* update the free count for this dmap */
3227 	le32_add_cpu(&dp->nfree, -nblocks);
3228 
3229 	/* reconstruct summary tree */
3230 	dbInitDmapTree(dp);
3231 
3232 	BMAP_LOCK(bmp);
3233 
3234 	/* if this allocation group is completely free,
3235 	 * update the highest active allocation group number
3236 	 * if this allocation group is the new max.
3237 	 */
3238 	agno = blkno >> bmp->db_agl2size;
3239 	if (agno > bmp->db_maxag)
3240 		bmp->db_maxag = agno;
3241 
3242 	/* update the free count for the allocation group and map */
3243 	bmp->db_agfree[agno] -= nblocks;
3244 	bmp->db_nfree -= nblocks;
3245 
3246 	BMAP_UNLOCK(bmp);
3247 
3248 	/* if the root has not changed, done. */
3249 	if (tp->stree[ROOT] == oldroot)
3250 		return (0);
3251 
3252 	/* root changed. bubble the change up to the dmap control pages.
3253 	 * if the adjustment of the upper level control pages fails,
3254 	 * backout the bit allocation (thus making everything consistent).
3255 	 */
3256 	if ((rc = dbAdjCtl(bmp, blkno, tp->stree[ROOT], 1, 0)))
3257 		dbFreeBits(bmp, dp, blkno, nblocks);
3258 
3259 	return (rc);
3260 }
3261 
3262 
3263 /*
3264  * NAME:	dbExtendFS()
3265  *
3266  * FUNCTION:	extend bmap from blkno for nblocks;
3267  *		dbExtendFS() updates bmap ready for dbAllocBottomUp();
3268  *
3269  * L2
3270  *  |
3271  *   L1---------------------------------L1
3272  *    |					 |
3273  *     L0---------L0---------L0		  L0---------L0---------L0
3274  *      |	   |	      |		   |	      |		 |
3275  *	 d0,...,dn  d0,...,dn  d0,...,dn    d0,...,dn  d0,...,dn  d0,.,dm;
3276  * L2L1L0d0,...,dnL0d0,...,dnL0d0,...,dnL1L0d0,...,dnL0d0,...,dnL0d0,..dm
3277  *
3278  * <---old---><----------------------------extend----------------------->
3279  */
dbExtendFS(struct inode * ipbmap,s64 blkno,s64 nblocks)3280 int dbExtendFS(struct inode *ipbmap, s64 blkno,	s64 nblocks)
3281 {
3282 	struct jfs_sb_info *sbi = JFS_SBI(ipbmap->i_sb);
3283 	int nbperpage = sbi->nbperpage;
3284 	int i, i0 = true, j, j0 = true, k, n;
3285 	s64 newsize;
3286 	s64 p;
3287 	struct metapage *mp, *l2mp, *l1mp = NULL, *l0mp = NULL;
3288 	struct dmapctl *l2dcp, *l1dcp, *l0dcp;
3289 	struct dmap *dp;
3290 	s8 *l0leaf, *l1leaf, *l2leaf;
3291 	struct bmap *bmp = sbi->bmap;
3292 	int agno, l2agsize, oldl2agsize;
3293 	s64 ag_rem;
3294 
3295 	newsize = blkno + nblocks;
3296 
3297 	jfs_info("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld",
3298 		 (long long) blkno, (long long) nblocks, (long long) newsize);
3299 
3300 	/*
3301 	 *	initialize bmap control page.
3302 	 *
3303 	 * all the data in bmap control page should exclude
3304 	 * the mkfs hidden dmap page.
3305 	 */
3306 
3307 	/* update mapsize */
3308 	bmp->db_mapsize = newsize;
3309 	bmp->db_maxlevel = BMAPSZTOLEV(bmp->db_mapsize);
3310 
3311 	/* compute new AG size */
3312 	l2agsize = dbGetL2AGSize(newsize);
3313 	oldl2agsize = bmp->db_agl2size;
3314 
3315 	bmp->db_agl2size = l2agsize;
3316 	bmp->db_agsize = 1 << l2agsize;
3317 
3318 	/* compute new number of AG */
3319 	agno = bmp->db_numag;
3320 	bmp->db_numag = newsize >> l2agsize;
3321 	bmp->db_numag += ((u32) newsize % (u32) bmp->db_agsize) ? 1 : 0;
3322 
3323 	/*
3324 	 *	reconfigure db_agfree[]
3325 	 * from old AG configuration to new AG configuration;
3326 	 *
3327 	 * coalesce contiguous k (newAGSize/oldAGSize) AGs;
3328 	 * i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn;
3329 	 * note: new AG size = old AG size * (2**x).
3330 	 */
3331 	if (l2agsize == oldl2agsize)
3332 		goto extend;
3333 	k = 1 << (l2agsize - oldl2agsize);
3334 	ag_rem = bmp->db_agfree[0];	/* save agfree[0] */
3335 	for (i = 0, n = 0; i < agno; n++) {
3336 		bmp->db_agfree[n] = 0;	/* init collection point */
3337 
3338 		/* coalesce contiguous k AGs; */
3339 		for (j = 0; j < k && i < agno; j++, i++) {
3340 			/* merge AGi to AGn */
3341 			bmp->db_agfree[n] += bmp->db_agfree[i];
3342 		}
3343 	}
3344 	bmp->db_agfree[0] += ag_rem;	/* restore agfree[0] */
3345 
3346 	for (; n < MAXAG; n++)
3347 		bmp->db_agfree[n] = 0;
3348 
3349 	/*
3350 	 * update highest active ag number
3351 	 */
3352 
3353 	bmp->db_maxag = bmp->db_maxag / k;
3354 
3355 	/*
3356 	 *	extend bmap
3357 	 *
3358 	 * update bit maps and corresponding level control pages;
3359 	 * global control page db_nfree, db_agfree[agno], db_maxfreebud;
3360 	 */
3361       extend:
3362 	/* get L2 page */
3363 	p = BMAPBLKNO + nbperpage;	/* L2 page */
3364 	l2mp = read_metapage(ipbmap, p, PSIZE, 0);
3365 	if (!l2mp) {
3366 		jfs_error(ipbmap->i_sb, "dbExtendFS: L2 page could not be read");
3367 		return -EIO;
3368 	}
3369 	l2dcp = (struct dmapctl *) l2mp->data;
3370 
3371 	/* compute start L1 */
3372 	k = blkno >> L2MAXL1SIZE;
3373 	l2leaf = l2dcp->stree + CTLLEAFIND + k;
3374 	p = BLKTOL1(blkno, sbi->l2nbperpage);	/* L1 page */
3375 
3376 	/*
3377 	 * extend each L1 in L2
3378 	 */
3379 	for (; k < LPERCTL; k++, p += nbperpage) {
3380 		/* get L1 page */
3381 		if (j0) {
3382 			/* read in L1 page: (blkno & (MAXL1SIZE - 1)) */
3383 			l1mp = read_metapage(ipbmap, p, PSIZE, 0);
3384 			if (l1mp == NULL)
3385 				goto errout;
3386 			l1dcp = (struct dmapctl *) l1mp->data;
3387 
3388 			/* compute start L0 */
3389 			j = (blkno & (MAXL1SIZE - 1)) >> L2MAXL0SIZE;
3390 			l1leaf = l1dcp->stree + CTLLEAFIND + j;
3391 			p = BLKTOL0(blkno, sbi->l2nbperpage);
3392 			j0 = false;
3393 		} else {
3394 			/* assign/init L1 page */
3395 			l1mp = get_metapage(ipbmap, p, PSIZE, 0);
3396 			if (l1mp == NULL)
3397 				goto errout;
3398 
3399 			l1dcp = (struct dmapctl *) l1mp->data;
3400 
3401 			/* compute start L0 */
3402 			j = 0;
3403 			l1leaf = l1dcp->stree + CTLLEAFIND;
3404 			p += nbperpage;	/* 1st L0 of L1.k */
3405 		}
3406 
3407 		/*
3408 		 * extend each L0 in L1
3409 		 */
3410 		for (; j < LPERCTL; j++) {
3411 			/* get L0 page */
3412 			if (i0) {
3413 				/* read in L0 page: (blkno & (MAXL0SIZE - 1)) */
3414 
3415 				l0mp = read_metapage(ipbmap, p, PSIZE, 0);
3416 				if (l0mp == NULL)
3417 					goto errout;
3418 				l0dcp = (struct dmapctl *) l0mp->data;
3419 
3420 				/* compute start dmap */
3421 				i = (blkno & (MAXL0SIZE - 1)) >>
3422 				    L2BPERDMAP;
3423 				l0leaf = l0dcp->stree + CTLLEAFIND + i;
3424 				p = BLKTODMAP(blkno,
3425 					      sbi->l2nbperpage);
3426 				i0 = false;
3427 			} else {
3428 				/* assign/init L0 page */
3429 				l0mp = get_metapage(ipbmap, p, PSIZE, 0);
3430 				if (l0mp == NULL)
3431 					goto errout;
3432 
3433 				l0dcp = (struct dmapctl *) l0mp->data;
3434 
3435 				/* compute start dmap */
3436 				i = 0;
3437 				l0leaf = l0dcp->stree + CTLLEAFIND;
3438 				p += nbperpage;	/* 1st dmap of L0.j */
3439 			}
3440 
3441 			/*
3442 			 * extend each dmap in L0
3443 			 */
3444 			for (; i < LPERCTL; i++) {
3445 				/*
3446 				 * reconstruct the dmap page, and
3447 				 * initialize corresponding parent L0 leaf
3448 				 */
3449 				if ((n = blkno & (BPERDMAP - 1))) {
3450 					/* read in dmap page: */
3451 					mp = read_metapage(ipbmap, p,
3452 							   PSIZE, 0);
3453 					if (mp == NULL)
3454 						goto errout;
3455 					n = min(nblocks, (s64)BPERDMAP - n);
3456 				} else {
3457 					/* assign/init dmap page */
3458 					mp = read_metapage(ipbmap, p,
3459 							   PSIZE, 0);
3460 					if (mp == NULL)
3461 						goto errout;
3462 
3463 					n = min(nblocks, (s64)BPERDMAP);
3464 				}
3465 
3466 				dp = (struct dmap *) mp->data;
3467 				*l0leaf = dbInitDmap(dp, blkno, n);
3468 
3469 				bmp->db_nfree += n;
3470 				agno = le64_to_cpu(dp->start) >> l2agsize;
3471 				bmp->db_agfree[agno] += n;
3472 
3473 				write_metapage(mp);
3474 
3475 				l0leaf++;
3476 				p += nbperpage;
3477 
3478 				blkno += n;
3479 				nblocks -= n;
3480 				if (nblocks == 0)
3481 					break;
3482 			}	/* for each dmap in a L0 */
3483 
3484 			/*
3485 			 * build current L0 page from its leaves, and
3486 			 * initialize corresponding parent L1 leaf
3487 			 */
3488 			*l1leaf = dbInitDmapCtl(l0dcp, 0, ++i);
3489 			write_metapage(l0mp);
3490 			l0mp = NULL;
3491 
3492 			if (nblocks)
3493 				l1leaf++;	/* continue for next L0 */
3494 			else {
3495 				/* more than 1 L0 ? */
3496 				if (j > 0)
3497 					break;	/* build L1 page */
3498 				else {
3499 					/* summarize in global bmap page */
3500 					bmp->db_maxfreebud = *l1leaf;
3501 					release_metapage(l1mp);
3502 					release_metapage(l2mp);
3503 					goto finalize;
3504 				}
3505 			}
3506 		}		/* for each L0 in a L1 */
3507 
3508 		/*
3509 		 * build current L1 page from its leaves, and
3510 		 * initialize corresponding parent L2 leaf
3511 		 */
3512 		*l2leaf = dbInitDmapCtl(l1dcp, 1, ++j);
3513 		write_metapage(l1mp);
3514 		l1mp = NULL;
3515 
3516 		if (nblocks)
3517 			l2leaf++;	/* continue for next L1 */
3518 		else {
3519 			/* more than 1 L1 ? */
3520 			if (k > 0)
3521 				break;	/* build L2 page */
3522 			else {
3523 				/* summarize in global bmap page */
3524 				bmp->db_maxfreebud = *l2leaf;
3525 				release_metapage(l2mp);
3526 				goto finalize;
3527 			}
3528 		}
3529 	}			/* for each L1 in a L2 */
3530 
3531 	jfs_error(ipbmap->i_sb,
3532 		  "dbExtendFS: function has not returned as expected");
3533 errout:
3534 	if (l0mp)
3535 		release_metapage(l0mp);
3536 	if (l1mp)
3537 		release_metapage(l1mp);
3538 	release_metapage(l2mp);
3539 	return -EIO;
3540 
3541 	/*
3542 	 *	finalize bmap control page
3543 	 */
3544 finalize:
3545 
3546 	return 0;
3547 }
3548 
3549 
3550 /*
3551  *	dbFinalizeBmap()
3552  */
dbFinalizeBmap(struct inode * ipbmap)3553 void dbFinalizeBmap(struct inode *ipbmap)
3554 {
3555 	struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
3556 	int actags, inactags, l2nl;
3557 	s64 ag_rem, actfree, inactfree, avgfree;
3558 	int i, n;
3559 
3560 	/*
3561 	 *	finalize bmap control page
3562 	 */
3563 //finalize:
3564 	/*
3565 	 * compute db_agpref: preferred ag to allocate from
3566 	 * (the leftmost ag with average free space in it);
3567 	 */
3568 //agpref:
3569 	/* get the number of active ags and inacitve ags */
3570 	actags = bmp->db_maxag + 1;
3571 	inactags = bmp->db_numag - actags;
3572 	ag_rem = bmp->db_mapsize & (bmp->db_agsize - 1);	/* ??? */
3573 
3574 	/* determine how many blocks are in the inactive allocation
3575 	 * groups. in doing this, we must account for the fact that
3576 	 * the rightmost group might be a partial group (i.e. file
3577 	 * system size is not a multiple of the group size).
3578 	 */
3579 	inactfree = (inactags && ag_rem) ?
3580 	    ((inactags - 1) << bmp->db_agl2size) + ag_rem
3581 	    : inactags << bmp->db_agl2size;
3582 
3583 	/* determine how many free blocks are in the active
3584 	 * allocation groups plus the average number of free blocks
3585 	 * within the active ags.
3586 	 */
3587 	actfree = bmp->db_nfree - inactfree;
3588 	avgfree = (u32) actfree / (u32) actags;
3589 
3590 	/* if the preferred allocation group has not average free space.
3591 	 * re-establish the preferred group as the leftmost
3592 	 * group with average free space.
3593 	 */
3594 	if (bmp->db_agfree[bmp->db_agpref] < avgfree) {
3595 		for (bmp->db_agpref = 0; bmp->db_agpref < actags;
3596 		     bmp->db_agpref++) {
3597 			if (bmp->db_agfree[bmp->db_agpref] >= avgfree)
3598 				break;
3599 		}
3600 		if (bmp->db_agpref >= bmp->db_numag) {
3601 			jfs_error(ipbmap->i_sb,
3602 				  "cannot find ag with average freespace");
3603 		}
3604 	}
3605 
3606 	/*
3607 	 * compute db_aglevel, db_agheight, db_width, db_agstart:
3608 	 * an ag is covered in aglevel dmapctl summary tree,
3609 	 * at agheight level height (from leaf) with agwidth number of nodes
3610 	 * each, which starts at agstart index node of the smmary tree node
3611 	 * array;
3612 	 */
3613 	bmp->db_aglevel = BMAPSZTOLEV(bmp->db_agsize);
3614 	l2nl =
3615 	    bmp->db_agl2size - (L2BPERDMAP + bmp->db_aglevel * L2LPERCTL);
3616 	bmp->db_agheight = l2nl >> 1;
3617 	bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheight << 1));
3618 	for (i = 5 - bmp->db_agheight, bmp->db_agstart = 0, n = 1; i > 0;
3619 	     i--) {
3620 		bmp->db_agstart += n;
3621 		n <<= 2;
3622 	}
3623 
3624 }
3625 
3626 
3627 /*
3628  * NAME:	dbInitDmap()/ujfs_idmap_page()
3629  *
3630  * FUNCTION:	initialize working/persistent bitmap of the dmap page
3631  *		for the specified number of blocks:
3632  *
3633  *		at entry, the bitmaps had been initialized as free (ZEROS);
3634  *		The number of blocks will only account for the actually
3635  *		existing blocks. Blocks which don't actually exist in
3636  *		the aggregate will be marked as allocated (ONES);
3637  *
3638  * PARAMETERS:
3639  *	dp	- pointer to page of map
3640  *	nblocks	- number of blocks this page
3641  *
3642  * RETURNS: NONE
3643  */
dbInitDmap(struct dmap * dp,s64 Blkno,int nblocks)3644 static int dbInitDmap(struct dmap * dp, s64 Blkno, int nblocks)
3645 {
3646 	int blkno, w, b, r, nw, nb, i;
3647 
3648 	/* starting block number within the dmap */
3649 	blkno = Blkno & (BPERDMAP - 1);
3650 
3651 	if (blkno == 0) {
3652 		dp->nblocks = dp->nfree = cpu_to_le32(nblocks);
3653 		dp->start = cpu_to_le64(Blkno);
3654 
3655 		if (nblocks == BPERDMAP) {
3656 			memset(&dp->wmap[0], 0, LPERDMAP * 4);
3657 			memset(&dp->pmap[0], 0, LPERDMAP * 4);
3658 			goto initTree;
3659 		}
3660 	} else {
3661 		le32_add_cpu(&dp->nblocks, nblocks);
3662 		le32_add_cpu(&dp->nfree, nblocks);
3663 	}
3664 
3665 	/* word number containing start block number */
3666 	w = blkno >> L2DBWORD;
3667 
3668 	/*
3669 	 * free the bits corresponding to the block range (ZEROS):
3670 	 * note: not all bits of the first and last words may be contained
3671 	 * within the block range.
3672 	 */
3673 	for (r = nblocks; r > 0; r -= nb, blkno += nb) {
3674 		/* number of bits preceding range to be freed in the word */
3675 		b = blkno & (DBWORD - 1);
3676 		/* number of bits to free in the word */
3677 		nb = min(r, DBWORD - b);
3678 
3679 		/* is partial word to be freed ? */
3680 		if (nb < DBWORD) {
3681 			/* free (set to 0) from the bitmap word */
3682 			dp->wmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3683 						     >> b));
3684 			dp->pmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3685 						     >> b));
3686 
3687 			/* skip the word freed */
3688 			w++;
3689 		} else {
3690 			/* free (set to 0) contiguous bitmap words */
3691 			nw = r >> L2DBWORD;
3692 			memset(&dp->wmap[w], 0, nw * 4);
3693 			memset(&dp->pmap[w], 0, nw * 4);
3694 
3695 			/* skip the words freed */
3696 			nb = nw << L2DBWORD;
3697 			w += nw;
3698 		}
3699 	}
3700 
3701 	/*
3702 	 * mark bits following the range to be freed (non-existing
3703 	 * blocks) as allocated (ONES)
3704 	 */
3705 
3706 	if (blkno == BPERDMAP)
3707 		goto initTree;
3708 
3709 	/* the first word beyond the end of existing blocks */
3710 	w = blkno >> L2DBWORD;
3711 
3712 	/* does nblocks fall on a 32-bit boundary ? */
3713 	b = blkno & (DBWORD - 1);
3714 	if (b) {
3715 		/* mark a partial word allocated */
3716 		dp->wmap[w] = dp->pmap[w] = cpu_to_le32(ONES >> b);
3717 		w++;
3718 	}
3719 
3720 	/* set the rest of the words in the page to allocated (ONES) */
3721 	for (i = w; i < LPERDMAP; i++)
3722 		dp->pmap[i] = dp->wmap[i] = cpu_to_le32(ONES);
3723 
3724 	/*
3725 	 * init tree
3726 	 */
3727       initTree:
3728 	return (dbInitDmapTree(dp));
3729 }
3730 
3731 
3732 /*
3733  * NAME:	dbInitDmapTree()/ujfs_complete_dmap()
3734  *
3735  * FUNCTION:	initialize summary tree of the specified dmap:
3736  *
3737  *		at entry, bitmap of the dmap has been initialized;
3738  *
3739  * PARAMETERS:
3740  *	dp	- dmap to complete
3741  *	blkno	- starting block number for this dmap
3742  *	treemax	- will be filled in with max free for this dmap
3743  *
3744  * RETURNS:	max free string at the root of the tree
3745  */
dbInitDmapTree(struct dmap * dp)3746 static int dbInitDmapTree(struct dmap * dp)
3747 {
3748 	struct dmaptree *tp;
3749 	s8 *cp;
3750 	int i;
3751 
3752 	/* init fixed info of tree */
3753 	tp = &dp->tree;
3754 	tp->nleafs = cpu_to_le32(LPERDMAP);
3755 	tp->l2nleafs = cpu_to_le32(L2LPERDMAP);
3756 	tp->leafidx = cpu_to_le32(LEAFIND);
3757 	tp->height = cpu_to_le32(4);
3758 	tp->budmin = BUDMIN;
3759 
3760 	/* init each leaf from corresponding wmap word:
3761 	 * note: leaf is set to NOFREE(-1) if all blocks of corresponding
3762 	 * bitmap word are allocated.
3763 	 */
3764 	cp = tp->stree + le32_to_cpu(tp->leafidx);
3765 	for (i = 0; i < LPERDMAP; i++)
3766 		*cp++ = dbMaxBud((u8 *) & dp->wmap[i]);
3767 
3768 	/* build the dmap's binary buddy summary tree */
3769 	return (dbInitTree(tp));
3770 }
3771 
3772 
3773 /*
3774  * NAME:	dbInitTree()/ujfs_adjtree()
3775  *
3776  * FUNCTION:	initialize binary buddy summary tree of a dmap or dmapctl.
3777  *
3778  *		at entry, the leaves of the tree has been initialized
3779  *		from corresponding bitmap word or root of summary tree
3780  *		of the child control page;
3781  *		configure binary buddy system at the leaf level, then
3782  *		bubble up the values of the leaf nodes up the tree.
3783  *
3784  * PARAMETERS:
3785  *	cp	- Pointer to the root of the tree
3786  *	l2leaves- Number of leaf nodes as a power of 2
3787  *	l2min	- Number of blocks that can be covered by a leaf
3788  *		  as a power of 2
3789  *
3790  * RETURNS: max free string at the root of the tree
3791  */
dbInitTree(struct dmaptree * dtp)3792 static int dbInitTree(struct dmaptree * dtp)
3793 {
3794 	int l2max, l2free, bsize, nextb, i;
3795 	int child, parent, nparent;
3796 	s8 *tp, *cp, *cp1;
3797 
3798 	tp = dtp->stree;
3799 
3800 	/* Determine the maximum free string possible for the leaves */
3801 	l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin;
3802 
3803 	/*
3804 	 * configure the leaf levevl into binary buddy system
3805 	 *
3806 	 * Try to combine buddies starting with a buddy size of 1
3807 	 * (i.e. two leaves). At a buddy size of 1 two buddy leaves
3808 	 * can be combined if both buddies have a maximum free of l2min;
3809 	 * the combination will result in the left-most buddy leaf having
3810 	 * a maximum free of l2min+1.
3811 	 * After processing all buddies for a given size, process buddies
3812 	 * at the next higher buddy size (i.e. current size * 2) and
3813 	 * the next maximum free (current free + 1).
3814 	 * This continues until the maximum possible buddy combination
3815 	 * yields maximum free.
3816 	 */
3817 	for (l2free = dtp->budmin, bsize = 1; l2free < l2max;
3818 	     l2free++, bsize = nextb) {
3819 		/* get next buddy size == current buddy pair size */
3820 		nextb = bsize << 1;
3821 
3822 		/* scan each adjacent buddy pair at current buddy size */
3823 		for (i = 0, cp = tp + le32_to_cpu(dtp->leafidx);
3824 		     i < le32_to_cpu(dtp->nleafs);
3825 		     i += nextb, cp += nextb) {
3826 			/* coalesce if both adjacent buddies are max free */
3827 			if (*cp == l2free && *(cp + bsize) == l2free) {
3828 				*cp = l2free + 1;	/* left take right */
3829 				*(cp + bsize) = -1;	/* right give left */
3830 			}
3831 		}
3832 	}
3833 
3834 	/*
3835 	 * bubble summary information of leaves up the tree.
3836 	 *
3837 	 * Starting at the leaf node level, the four nodes described by
3838 	 * the higher level parent node are compared for a maximum free and
3839 	 * this maximum becomes the value of the parent node.
3840 	 * when all lower level nodes are processed in this fashion then
3841 	 * move up to the next level (parent becomes a lower level node) and
3842 	 * continue the process for that level.
3843 	 */
3844 	for (child = le32_to_cpu(dtp->leafidx),
3845 	     nparent = le32_to_cpu(dtp->nleafs) >> 2;
3846 	     nparent > 0; nparent >>= 2, child = parent) {
3847 		/* get index of 1st node of parent level */
3848 		parent = (child - 1) >> 2;
3849 
3850 		/* set the value of the parent node as the maximum
3851 		 * of the four nodes of the current level.
3852 		 */
3853 		for (i = 0, cp = tp + child, cp1 = tp + parent;
3854 		     i < nparent; i++, cp += 4, cp1++)
3855 			*cp1 = TREEMAX(cp);
3856 	}
3857 
3858 	return (*tp);
3859 }
3860 
3861 
3862 /*
3863  *	dbInitDmapCtl()
3864  *
3865  * function: initialize dmapctl page
3866  */
dbInitDmapCtl(struct dmapctl * dcp,int level,int i)3867 static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i)
3868 {				/* start leaf index not covered by range */
3869 	s8 *cp;
3870 
3871 	dcp->nleafs = cpu_to_le32(LPERCTL);
3872 	dcp->l2nleafs = cpu_to_le32(L2LPERCTL);
3873 	dcp->leafidx = cpu_to_le32(CTLLEAFIND);
3874 	dcp->height = cpu_to_le32(5);
3875 	dcp->budmin = L2BPERDMAP + L2LPERCTL * level;
3876 
3877 	/*
3878 	 * initialize the leaves of current level that were not covered
3879 	 * by the specified input block range (i.e. the leaves have no
3880 	 * low level dmapctl or dmap).
3881 	 */
3882 	cp = &dcp->stree[CTLLEAFIND + i];
3883 	for (; i < LPERCTL; i++)
3884 		*cp++ = NOFREE;
3885 
3886 	/* build the dmap's binary buddy summary tree */
3887 	return (dbInitTree((struct dmaptree *) dcp));
3888 }
3889 
3890 
3891 /*
3892  * NAME:	dbGetL2AGSize()/ujfs_getagl2size()
3893  *
3894  * FUNCTION:	Determine log2(allocation group size) from aggregate size
3895  *
3896  * PARAMETERS:
3897  *	nblocks	- Number of blocks in aggregate
3898  *
3899  * RETURNS: log2(allocation group size) in aggregate blocks
3900  */
dbGetL2AGSize(s64 nblocks)3901 static int dbGetL2AGSize(s64 nblocks)
3902 {
3903 	s64 sz;
3904 	s64 m;
3905 	int l2sz;
3906 
3907 	if (nblocks < BPERDMAP * MAXAG)
3908 		return (L2BPERDMAP);
3909 
3910 	/* round up aggregate size to power of 2 */
3911 	m = ((u64) 1 << (64 - 1));
3912 	for (l2sz = 64; l2sz >= 0; l2sz--, m >>= 1) {
3913 		if (m & nblocks)
3914 			break;
3915 	}
3916 
3917 	sz = (s64) 1 << l2sz;
3918 	if (sz < nblocks)
3919 		l2sz += 1;
3920 
3921 	/* agsize = roundupSize/max_number_of_ag */
3922 	return (l2sz - L2MAXAG);
3923 }
3924 
3925 
3926 /*
3927  * NAME:	dbMapFileSizeToMapSize()
3928  *
3929  * FUNCTION:	compute number of blocks the block allocation map file
3930  *		can cover from the map file size;
3931  *
3932  * RETURNS:	Number of blocks which can be covered by this block map file;
3933  */
3934 
3935 /*
3936  * maximum number of map pages at each level including control pages
3937  */
3938 #define MAXL0PAGES	(1 + LPERCTL)
3939 #define MAXL1PAGES	(1 + LPERCTL * MAXL0PAGES)
3940 #define MAXL2PAGES	(1 + LPERCTL * MAXL1PAGES)
3941 
3942 /*
3943  * convert number of map pages to the zero origin top dmapctl level
3944  */
3945 #define BMAPPGTOLEV(npages)	\
3946 	(((npages) <= 3 + MAXL0PAGES) ? 0 : \
3947 	 ((npages) <= 2 + MAXL1PAGES) ? 1 : 2)
3948 
dbMapFileSizeToMapSize(struct inode * ipbmap)3949 s64 dbMapFileSizeToMapSize(struct inode * ipbmap)
3950 {
3951 	struct super_block *sb = ipbmap->i_sb;
3952 	s64 nblocks;
3953 	s64 npages, ndmaps;
3954 	int level, i;
3955 	int complete, factor;
3956 
3957 	nblocks = ipbmap->i_size >> JFS_SBI(sb)->l2bsize;
3958 	npages = nblocks >> JFS_SBI(sb)->l2nbperpage;
3959 	level = BMAPPGTOLEV(npages);
3960 
3961 	/* At each level, accumulate the number of dmap pages covered by
3962 	 * the number of full child levels below it;
3963 	 * repeat for the last incomplete child level.
3964 	 */
3965 	ndmaps = 0;
3966 	npages--;		/* skip the first global control page */
3967 	/* skip higher level control pages above top level covered by map */
3968 	npages -= (2 - level);
3969 	npages--;		/* skip top level's control page */
3970 	for (i = level; i >= 0; i--) {
3971 		factor =
3972 		    (i == 2) ? MAXL1PAGES : ((i == 1) ? MAXL0PAGES : 1);
3973 		complete = (u32) npages / factor;
3974 		ndmaps += complete * ((i == 2) ? LPERCTL * LPERCTL :
3975 				      ((i == 1) ? LPERCTL : 1));
3976 
3977 		/* pages in last/incomplete child */
3978 		npages = (u32) npages % factor;
3979 		/* skip incomplete child's level control page */
3980 		npages--;
3981 	}
3982 
3983 	/* convert the number of dmaps into the number of blocks
3984 	 * which can be covered by the dmaps;
3985 	 */
3986 	nblocks = ndmaps << L2BPERDMAP;
3987 
3988 	return (nblocks);
3989 }
3990