1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *   Copyright (C) International Business Machines Corp., 2000-2004
4  *   Portions Copyright (C) Tino Reichardt, 2012
5  */
6 
7 #include <linux/fs.h>
8 #include <linux/slab.h>
9 #include "jfs_incore.h"
10 #include "jfs_superblock.h"
11 #include "jfs_dmap.h"
12 #include "jfs_imap.h"
13 #include "jfs_lock.h"
14 #include "jfs_metapage.h"
15 #include "jfs_debug.h"
16 #include "jfs_discard.h"
17 
18 /*
19  *	SERIALIZATION of the Block Allocation Map.
20  *
21  *	the working state of the block allocation map is accessed in
22  *	two directions:
23  *
24  *	1) allocation and free requests that start at the dmap
25  *	   level and move up through the dmap control pages (i.e.
26  *	   the vast majority of requests).
27  *
28  *	2) allocation requests that start at dmap control page
29  *	   level and work down towards the dmaps.
30  *
31  *	the serialization scheme used here is as follows.
32  *
33  *	requests which start at the bottom are serialized against each
34  *	other through buffers and each requests holds onto its buffers
35  *	as it works it way up from a single dmap to the required level
36  *	of dmap control page.
37  *	requests that start at the top are serialized against each other
38  *	and request that start from the bottom by the multiple read/single
39  *	write inode lock of the bmap inode. requests starting at the top
40  *	take this lock in write mode while request starting at the bottom
41  *	take the lock in read mode.  a single top-down request may proceed
42  *	exclusively while multiple bottoms-up requests may proceed
43  *	simultaneously (under the protection of busy buffers).
44  *
45  *	in addition to information found in dmaps and dmap control pages,
46  *	the working state of the block allocation map also includes read/
47  *	write information maintained in the bmap descriptor (i.e. total
48  *	free block count, allocation group level free block counts).
49  *	a single exclusive lock (BMAP_LOCK) is used to guard this information
50  *	in the face of multiple-bottoms up requests.
51  *	(lock ordering: IREAD_LOCK, BMAP_LOCK);
52  *
53  *	accesses to the persistent state of the block allocation map (limited
54  *	to the persistent bitmaps in dmaps) is guarded by (busy) buffers.
55  */
56 
57 #define BMAP_LOCK_INIT(bmp)	mutex_init(&bmp->db_bmaplock)
58 #define BMAP_LOCK(bmp)		mutex_lock(&bmp->db_bmaplock)
59 #define BMAP_UNLOCK(bmp)	mutex_unlock(&bmp->db_bmaplock)
60 
61 /*
62  * forward references
63  */
64 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
65 			int nblocks);
66 static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval);
67 static int dbBackSplit(dmtree_t * tp, int leafno);
68 static int dbJoin(dmtree_t * tp, int leafno, int newval);
69 static void dbAdjTree(dmtree_t * tp, int leafno, int newval);
70 static int dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc,
71 		    int level);
72 static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results);
73 static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
74 		       int nblocks);
75 static int dbAllocNear(struct bmap * bmp, struct dmap * dp, s64 blkno,
76 		       int nblocks,
77 		       int l2nb, s64 * results);
78 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
79 		       int nblocks);
80 static int dbAllocDmapLev(struct bmap * bmp, struct dmap * dp, int nblocks,
81 			  int l2nb,
82 			  s64 * results);
83 static int dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb,
84 		     s64 * results);
85 static int dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno,
86 		      s64 * results);
87 static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks);
88 static int dbFindBits(u32 word, int l2nb);
89 static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno);
90 static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx);
91 static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
92 		      int nblocks);
93 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
94 		      int nblocks);
95 static int dbMaxBud(u8 * cp);
96 static int blkstol2(s64 nb);
97 
98 static int cntlz(u32 value);
99 static int cnttz(u32 word);
100 
101 static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
102 			 int nblocks);
103 static int dbInitDmap(struct dmap * dp, s64 blkno, int nblocks);
104 static int dbInitDmapTree(struct dmap * dp);
105 static int dbInitTree(struct dmaptree * dtp);
106 static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i);
107 static int dbGetL2AGSize(s64 nblocks);
108 
109 /*
110  *	buddy table
111  *
112  * table used for determining buddy sizes within characters of
113  * dmap bitmap words.  the characters themselves serve as indexes
114  * into the table, with the table elements yielding the maximum
115  * binary buddy of free bits within the character.
116  */
117 static const s8 budtab[256] = {
118 	3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
119 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
120 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
121 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
122 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
123 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
124 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
125 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
126 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
127 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
128 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
129 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
130 	2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
131 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
132 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
133 	2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1
134 };
135 
136 /*
137  * NAME:	dbMount()
138  *
139  * FUNCTION:	initializate the block allocation map.
140  *
141  *		memory is allocated for the in-core bmap descriptor and
142  *		the in-core descriptor is initialized from disk.
143  *
144  * PARAMETERS:
145  *	ipbmap	- pointer to in-core inode for the block map.
146  *
147  * RETURN VALUES:
148  *	0	- success
149  *	-ENOMEM	- insufficient memory
150  *	-EIO	- i/o error
151  *	-EINVAL - wrong bmap data
152  */
dbMount(struct inode * ipbmap)153 int dbMount(struct inode *ipbmap)
154 {
155 	struct bmap *bmp;
156 	struct dbmap_disk *dbmp_le;
157 	struct metapage *mp;
158 	int i;
159 
160 	/*
161 	 * allocate/initialize the in-memory bmap descriptor
162 	 */
163 	/* allocate memory for the in-memory bmap descriptor */
164 	bmp = kmalloc(sizeof(struct bmap), GFP_KERNEL);
165 	if (bmp == NULL)
166 		return -ENOMEM;
167 
168 	/* read the on-disk bmap descriptor. */
169 	mp = read_metapage(ipbmap,
170 			   BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
171 			   PSIZE, 0);
172 	if (mp == NULL) {
173 		kfree(bmp);
174 		return -EIO;
175 	}
176 
177 	/* copy the on-disk bmap descriptor to its in-memory version. */
178 	dbmp_le = (struct dbmap_disk *) mp->data;
179 	bmp->db_mapsize = le64_to_cpu(dbmp_le->dn_mapsize);
180 	bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree);
181 	bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage);
182 	bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag);
183 	if (!bmp->db_numag) {
184 		release_metapage(mp);
185 		kfree(bmp);
186 		return -EINVAL;
187 	}
188 
189 	bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel);
190 	bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag);
191 	bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref);
192 	bmp->db_aglevel = le32_to_cpu(dbmp_le->dn_aglevel);
193 	bmp->db_agheight = le32_to_cpu(dbmp_le->dn_agheight);
194 	bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);
195 	bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart);
196 	bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size);
197 	for (i = 0; i < MAXAG; i++)
198 		bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]);
199 	bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize);
200 	bmp->db_maxfreebud = dbmp_le->dn_maxfreebud;
201 
202 	/* release the buffer. */
203 	release_metapage(mp);
204 
205 	/* bind the bmap inode and the bmap descriptor to each other. */
206 	bmp->db_ipbmap = ipbmap;
207 	JFS_SBI(ipbmap->i_sb)->bmap = bmp;
208 
209 	memset(bmp->db_active, 0, sizeof(bmp->db_active));
210 
211 	/*
212 	 * allocate/initialize the bmap lock
213 	 */
214 	BMAP_LOCK_INIT(bmp);
215 
216 	return (0);
217 }
218 
219 
220 /*
221  * NAME:	dbUnmount()
222  *
223  * FUNCTION:	terminate the block allocation map in preparation for
224  *		file system unmount.
225  *
226  *		the in-core bmap descriptor is written to disk and
227  *		the memory for this descriptor is freed.
228  *
229  * PARAMETERS:
230  *	ipbmap	- pointer to in-core inode for the block map.
231  *
232  * RETURN VALUES:
233  *	0	- success
234  *	-EIO	- i/o error
235  */
dbUnmount(struct inode * ipbmap,int mounterror)236 int dbUnmount(struct inode *ipbmap, int mounterror)
237 {
238 	struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
239 
240 	if (!(mounterror || isReadOnly(ipbmap)))
241 		dbSync(ipbmap);
242 
243 	/*
244 	 * Invalidate the page cache buffers
245 	 */
246 	truncate_inode_pages(ipbmap->i_mapping, 0);
247 
248 	/* free the memory for the in-memory bmap. */
249 	kfree(bmp);
250 
251 	return (0);
252 }
253 
254 /*
255  *	dbSync()
256  */
dbSync(struct inode * ipbmap)257 int dbSync(struct inode *ipbmap)
258 {
259 	struct dbmap_disk *dbmp_le;
260 	struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
261 	struct metapage *mp;
262 	int i;
263 
264 	/*
265 	 * write bmap global control page
266 	 */
267 	/* get the buffer for the on-disk bmap descriptor. */
268 	mp = read_metapage(ipbmap,
269 			   BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
270 			   PSIZE, 0);
271 	if (mp == NULL) {
272 		jfs_err("dbSync: read_metapage failed!");
273 		return -EIO;
274 	}
275 	/* copy the in-memory version of the bmap to the on-disk version */
276 	dbmp_le = (struct dbmap_disk *) mp->data;
277 	dbmp_le->dn_mapsize = cpu_to_le64(bmp->db_mapsize);
278 	dbmp_le->dn_nfree = cpu_to_le64(bmp->db_nfree);
279 	dbmp_le->dn_l2nbperpage = cpu_to_le32(bmp->db_l2nbperpage);
280 	dbmp_le->dn_numag = cpu_to_le32(bmp->db_numag);
281 	dbmp_le->dn_maxlevel = cpu_to_le32(bmp->db_maxlevel);
282 	dbmp_le->dn_maxag = cpu_to_le32(bmp->db_maxag);
283 	dbmp_le->dn_agpref = cpu_to_le32(bmp->db_agpref);
284 	dbmp_le->dn_aglevel = cpu_to_le32(bmp->db_aglevel);
285 	dbmp_le->dn_agheight = cpu_to_le32(bmp->db_agheight);
286 	dbmp_le->dn_agwidth = cpu_to_le32(bmp->db_agwidth);
287 	dbmp_le->dn_agstart = cpu_to_le32(bmp->db_agstart);
288 	dbmp_le->dn_agl2size = cpu_to_le32(bmp->db_agl2size);
289 	for (i = 0; i < MAXAG; i++)
290 		dbmp_le->dn_agfree[i] = cpu_to_le64(bmp->db_agfree[i]);
291 	dbmp_le->dn_agsize = cpu_to_le64(bmp->db_agsize);
292 	dbmp_le->dn_maxfreebud = bmp->db_maxfreebud;
293 
294 	/* write the buffer */
295 	write_metapage(mp);
296 
297 	/*
298 	 * write out dirty pages of bmap
299 	 */
300 	filemap_write_and_wait(ipbmap->i_mapping);
301 
302 	diWriteSpecial(ipbmap, 0);
303 
304 	return (0);
305 }
306 
307 /*
308  * NAME:	dbFree()
309  *
310  * FUNCTION:	free the specified block range from the working block
311  *		allocation map.
312  *
313  *		the blocks will be free from the working map one dmap
314  *		at a time.
315  *
316  * PARAMETERS:
317  *	ip	- pointer to in-core inode;
318  *	blkno	- starting block number to be freed.
319  *	nblocks	- number of blocks to be freed.
320  *
321  * RETURN VALUES:
322  *	0	- success
323  *	-EIO	- i/o error
324  */
dbFree(struct inode * ip,s64 blkno,s64 nblocks)325 int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
326 {
327 	struct metapage *mp;
328 	struct dmap *dp;
329 	int nb, rc;
330 	s64 lblkno, rem;
331 	struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
332 	struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
333 	struct super_block *sb = ipbmap->i_sb;
334 
335 	IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
336 
337 	/* block to be freed better be within the mapsize. */
338 	if (unlikely((blkno == 0) || (blkno + nblocks > bmp->db_mapsize))) {
339 		IREAD_UNLOCK(ipbmap);
340 		printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
341 		       (unsigned long long) blkno,
342 		       (unsigned long long) nblocks);
343 		jfs_error(ip->i_sb, "block to be freed is outside the map\n");
344 		return -EIO;
345 	}
346 
347 	/**
348 	 * TRIM the blocks, when mounted with discard option
349 	 */
350 	if (JFS_SBI(sb)->flag & JFS_DISCARD)
351 		if (JFS_SBI(sb)->minblks_trim <= nblocks)
352 			jfs_issue_discard(ipbmap, blkno, nblocks);
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, "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 	if (mp)
389 		write_metapage(mp);
390 
391 	IREAD_UNLOCK(ipbmap);
392 
393 	return (0);
394 }
395 
396 
397 /*
398  * NAME:	dbUpdatePMap()
399  *
400  * FUNCTION:	update the allocation state (free or allocate) of the
401  *		specified block range in the persistent block allocation map.
402  *
403  *		the blocks will be updated in the persistent map one
404  *		dmap at a time.
405  *
406  * PARAMETERS:
407  *	ipbmap	- pointer to in-core inode for the block map.
408  *	free	- 'true' if block range is to be freed from the persistent
409  *		  map; 'false' if it is to be allocated.
410  *	blkno	- starting block number of the range.
411  *	nblocks	- number of contiguous blocks in the range.
412  *	tblk	- transaction block;
413  *
414  * RETURN VALUES:
415  *	0	- success
416  *	-EIO	- i/o error
417  */
418 int
dbUpdatePMap(struct inode * ipbmap,int free,s64 blkno,s64 nblocks,struct tblock * tblk)419 dbUpdatePMap(struct inode *ipbmap,
420 	     int free, s64 blkno, s64 nblocks, struct tblock * tblk)
421 {
422 	int nblks, dbitno, wbitno, rbits;
423 	int word, nbits, nwords;
424 	struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
425 	s64 lblkno, rem, lastlblkno;
426 	u32 mask;
427 	struct dmap *dp;
428 	struct metapage *mp;
429 	struct jfs_log *log;
430 	int lsn, difft, diffp;
431 	unsigned long flags;
432 
433 	/* the blocks better be within the mapsize. */
434 	if (blkno + nblocks > bmp->db_mapsize) {
435 		printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
436 		       (unsigned long long) blkno,
437 		       (unsigned long long) nblocks);
438 		jfs_error(ipbmap->i_sb, "blocks are outside the map\n");
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
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, "the hint is outside the map\n");
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 /*
873  * NAME:	dbReAlloc()
874  *
875  * FUNCTION:	attempt to extend a current allocation by a specified
876  *		number of blocks.
877  *
878  *		this routine attempts to satisfy the allocation request
879  *		by first trying to extend the existing allocation in
880  *		place by allocating the additional blocks as the blocks
881  *		immediately following the current allocation.  if these
882  *		blocks are not available, this routine will attempt to
883  *		allocate a new set of contiguous blocks large enough
884  *		to cover the existing allocation plus the additional
885  *		number of blocks required.
886  *
887  * PARAMETERS:
888  *	ip	    -  pointer to in-core inode requiring allocation.
889  *	blkno	    -  starting block of the current allocation.
890  *	nblocks	    -  number of contiguous blocks within the current
891  *		       allocation.
892  *	addnblocks  -  number of blocks to add to the allocation.
893  *	results	-      on successful return, set to the starting block number
894  *		       of the existing allocation if the existing allocation
895  *		       was extended in place or to a newly allocated contiguous
896  *		       range if the existing allocation could not be extended
897  *		       in place.
898  *
899  * RETURN VALUES:
900  *	0	- success
901  *	-ENOSPC	- insufficient disk resources
902  *	-EIO	- i/o error
903  */
904 int
dbReAlloc(struct inode * ip,s64 blkno,s64 nblocks,s64 addnblocks,s64 * results)905 dbReAlloc(struct inode *ip,
906 	  s64 blkno, s64 nblocks, s64 addnblocks, s64 * results)
907 {
908 	int rc;
909 
910 	/* try to extend the allocation in place.
911 	 */
912 	if ((rc = dbExtend(ip, blkno, nblocks, addnblocks)) == 0) {
913 		*results = blkno;
914 		return (0);
915 	} else {
916 		if (rc != -ENOSPC)
917 			return (rc);
918 	}
919 
920 	/* could not extend the allocation in place, so allocate a
921 	 * new set of blocks for the entire request (i.e. try to get
922 	 * a range of contiguous blocks large enough to cover the
923 	 * existing allocation plus the additional blocks.)
924 	 */
925 	return (dbAlloc
926 		(ip, blkno + nblocks - 1, addnblocks + nblocks, results));
927 }
928 
929 
930 /*
931  * NAME:	dbExtend()
932  *
933  * FUNCTION:	attempt to extend a current allocation by a specified
934  *		number of blocks.
935  *
936  *		this routine attempts to satisfy the allocation request
937  *		by first trying to extend the existing allocation in
938  *		place by allocating the additional blocks as the blocks
939  *		immediately following the current allocation.
940  *
941  * PARAMETERS:
942  *	ip	    -  pointer to in-core inode requiring allocation.
943  *	blkno	    -  starting block of the current allocation.
944  *	nblocks	    -  number of contiguous blocks within the current
945  *		       allocation.
946  *	addnblocks  -  number of blocks to add to the allocation.
947  *
948  * RETURN VALUES:
949  *	0	- success
950  *	-ENOSPC	- insufficient disk resources
951  *	-EIO	- i/o error
952  */
dbExtend(struct inode * ip,s64 blkno,s64 nblocks,s64 addnblocks)953 static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks)
954 {
955 	struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
956 	s64 lblkno, lastblkno, extblkno;
957 	uint rel_block;
958 	struct metapage *mp;
959 	struct dmap *dp;
960 	int rc;
961 	struct inode *ipbmap = sbi->ipbmap;
962 	struct bmap *bmp;
963 
964 	/*
965 	 * We don't want a non-aligned extent to cross a page boundary
966 	 */
967 	if (((rel_block = blkno & (sbi->nbperpage - 1))) &&
968 	    (rel_block + nblocks + addnblocks > sbi->nbperpage))
969 		return -ENOSPC;
970 
971 	/* get the last block of the current allocation */
972 	lastblkno = blkno + nblocks - 1;
973 
974 	/* determine the block number of the block following
975 	 * the existing allocation.
976 	 */
977 	extblkno = lastblkno + 1;
978 
979 	IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
980 
981 	/* better be within the file system */
982 	bmp = sbi->bmap;
983 	if (lastblkno < 0 || lastblkno >= bmp->db_mapsize) {
984 		IREAD_UNLOCK(ipbmap);
985 		jfs_error(ip->i_sb, "the block is outside the filesystem\n");
986 		return -EIO;
987 	}
988 
989 	/* we'll attempt to extend the current allocation in place by
990 	 * allocating the additional blocks as the blocks immediately
991 	 * following the current allocation.  we only try to extend the
992 	 * current allocation in place if the number of additional blocks
993 	 * can fit into a dmap, the last block of the current allocation
994 	 * is not the last block of the file system, and the start of the
995 	 * inplace extension is not on an allocation group boundary.
996 	 */
997 	if (addnblocks > BPERDMAP || extblkno >= bmp->db_mapsize ||
998 	    (extblkno & (bmp->db_agsize - 1)) == 0) {
999 		IREAD_UNLOCK(ipbmap);
1000 		return -ENOSPC;
1001 	}
1002 
1003 	/* get the buffer for the dmap containing the first block
1004 	 * of the extension.
1005 	 */
1006 	lblkno = BLKTODMAP(extblkno, bmp->db_l2nbperpage);
1007 	mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
1008 	if (mp == NULL) {
1009 		IREAD_UNLOCK(ipbmap);
1010 		return -EIO;
1011 	}
1012 
1013 	dp = (struct dmap *) mp->data;
1014 
1015 	/* try to allocate the blocks immediately following the
1016 	 * current allocation.
1017 	 */
1018 	rc = dbAllocNext(bmp, dp, extblkno, (int) addnblocks);
1019 
1020 	IREAD_UNLOCK(ipbmap);
1021 
1022 	/* were we successful ? */
1023 	if (rc == 0)
1024 		write_metapage(mp);
1025 	else
1026 		/* we were not successful */
1027 		release_metapage(mp);
1028 
1029 	return (rc);
1030 }
1031 
1032 
1033 /*
1034  * NAME:	dbAllocNext()
1035  *
1036  * FUNCTION:	attempt to allocate the blocks of the specified block
1037  *		range within a dmap.
1038  *
1039  * PARAMETERS:
1040  *	bmp	-  pointer to bmap descriptor
1041  *	dp	-  pointer to dmap.
1042  *	blkno	-  starting block number of the range.
1043  *	nblocks	-  number of contiguous free blocks of the range.
1044  *
1045  * RETURN VALUES:
1046  *	0	- success
1047  *	-ENOSPC	- insufficient disk resources
1048  *	-EIO	- i/o error
1049  *
1050  * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1051  */
dbAllocNext(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)1052 static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
1053 		       int nblocks)
1054 {
1055 	int dbitno, word, rembits, nb, nwords, wbitno, nw;
1056 	int l2size;
1057 	s8 *leaf;
1058 	u32 mask;
1059 
1060 	if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1061 		jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n");
1062 		return -EIO;
1063 	}
1064 
1065 	/* pick up a pointer to the leaves of the dmap tree.
1066 	 */
1067 	leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1068 
1069 	/* determine the bit number and word within the dmap of the
1070 	 * starting block.
1071 	 */
1072 	dbitno = blkno & (BPERDMAP - 1);
1073 	word = dbitno >> L2DBWORD;
1074 
1075 	/* check if the specified block range is contained within
1076 	 * this dmap.
1077 	 */
1078 	if (dbitno + nblocks > BPERDMAP)
1079 		return -ENOSPC;
1080 
1081 	/* check if the starting leaf indicates that anything
1082 	 * is free.
1083 	 */
1084 	if (leaf[word] == NOFREE)
1085 		return -ENOSPC;
1086 
1087 	/* check the dmaps words corresponding to block range to see
1088 	 * if the block range is free.  not all bits of the first and
1089 	 * last words may be contained within the block range.  if this
1090 	 * is the case, we'll work against those words (i.e. partial first
1091 	 * and/or last) on an individual basis (a single pass) and examine
1092 	 * the actual bits to determine if they are free.  a single pass
1093 	 * will be used for all dmap words fully contained within the
1094 	 * specified range.  within this pass, the leaves of the dmap
1095 	 * tree will be examined to determine if the blocks are free. a
1096 	 * single leaf may describe the free space of multiple dmap
1097 	 * words, so we may visit only a subset of the actual leaves
1098 	 * corresponding to the dmap words of the block range.
1099 	 */
1100 	for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
1101 		/* determine the bit number within the word and
1102 		 * the number of bits within the word.
1103 		 */
1104 		wbitno = dbitno & (DBWORD - 1);
1105 		nb = min(rembits, DBWORD - wbitno);
1106 
1107 		/* check if only part of the word is to be examined.
1108 		 */
1109 		if (nb < DBWORD) {
1110 			/* check if the bits are free.
1111 			 */
1112 			mask = (ONES << (DBWORD - nb) >> wbitno);
1113 			if ((mask & ~le32_to_cpu(dp->wmap[word])) != mask)
1114 				return -ENOSPC;
1115 
1116 			word += 1;
1117 		} else {
1118 			/* one or more dmap words are fully contained
1119 			 * within the block range.  determine how many
1120 			 * words and how many bits.
1121 			 */
1122 			nwords = rembits >> L2DBWORD;
1123 			nb = nwords << L2DBWORD;
1124 
1125 			/* now examine the appropriate leaves to determine
1126 			 * if the blocks are free.
1127 			 */
1128 			while (nwords > 0) {
1129 				/* does the leaf describe any free space ?
1130 				 */
1131 				if (leaf[word] < BUDMIN)
1132 					return -ENOSPC;
1133 
1134 				/* determine the l2 number of bits provided
1135 				 * by this leaf.
1136 				 */
1137 				l2size =
1138 				    min_t(int, leaf[word], NLSTOL2BSZ(nwords));
1139 
1140 				/* determine how many words were handled.
1141 				 */
1142 				nw = BUDSIZE(l2size, BUDMIN);
1143 
1144 				nwords -= nw;
1145 				word += nw;
1146 			}
1147 		}
1148 	}
1149 
1150 	/* allocate the blocks.
1151 	 */
1152 	return (dbAllocDmap(bmp, dp, blkno, nblocks));
1153 }
1154 
1155 
1156 /*
1157  * NAME:	dbAllocNear()
1158  *
1159  * FUNCTION:	attempt to allocate a number of contiguous free blocks near
1160  *		a specified block (hint) within a dmap.
1161  *
1162  *		starting with the dmap leaf that covers the hint, we'll
1163  *		check the next four contiguous leaves for sufficient free
1164  *		space.  if sufficient free space is found, we'll allocate
1165  *		the desired free space.
1166  *
1167  * PARAMETERS:
1168  *	bmp	-  pointer to bmap descriptor
1169  *	dp	-  pointer to dmap.
1170  *	blkno	-  block number to allocate near.
1171  *	nblocks	-  actual number of contiguous free blocks desired.
1172  *	l2nb	-  log2 number of contiguous free blocks desired.
1173  *	results	-  on successful return, set to the starting block number
1174  *		   of the newly allocated range.
1175  *
1176  * RETURN VALUES:
1177  *	0	- success
1178  *	-ENOSPC	- insufficient disk resources
1179  *	-EIO	- i/o error
1180  *
1181  * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1182  */
1183 static int
dbAllocNear(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks,int l2nb,s64 * results)1184 dbAllocNear(struct bmap * bmp,
1185 	    struct dmap * dp, s64 blkno, int nblocks, int l2nb, s64 * results)
1186 {
1187 	int word, lword, rc;
1188 	s8 *leaf;
1189 
1190 	if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1191 		jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n");
1192 		return -EIO;
1193 	}
1194 
1195 	leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1196 
1197 	/* determine the word within the dmap that holds the hint
1198 	 * (i.e. blkno).  also, determine the last word in the dmap
1199 	 * that we'll include in our examination.
1200 	 */
1201 	word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
1202 	lword = min(word + 4, LPERDMAP);
1203 
1204 	/* examine the leaves for sufficient free space.
1205 	 */
1206 	for (; word < lword; word++) {
1207 		/* does the leaf describe sufficient free space ?
1208 		 */
1209 		if (leaf[word] < l2nb)
1210 			continue;
1211 
1212 		/* determine the block number within the file system
1213 		 * of the first block described by this dmap word.
1214 		 */
1215 		blkno = le64_to_cpu(dp->start) + (word << L2DBWORD);
1216 
1217 		/* if not all bits of the dmap word are free, get the
1218 		 * starting bit number within the dmap word of the required
1219 		 * string of free bits and adjust the block number with the
1220 		 * value.
1221 		 */
1222 		if (leaf[word] < BUDMIN)
1223 			blkno +=
1224 			    dbFindBits(le32_to_cpu(dp->wmap[word]), l2nb);
1225 
1226 		/* allocate the blocks.
1227 		 */
1228 		if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1229 			*results = blkno;
1230 
1231 		return (rc);
1232 	}
1233 
1234 	return -ENOSPC;
1235 }
1236 
1237 
1238 /*
1239  * NAME:	dbAllocAG()
1240  *
1241  * FUNCTION:	attempt to allocate the specified number of contiguous
1242  *		free blocks within the specified allocation group.
1243  *
1244  *		unless the allocation group size is equal to the number
1245  *		of blocks per dmap, the dmap control pages will be used to
1246  *		find the required free space, if available.  we start the
1247  *		search at the highest dmap control page level which
1248  *		distinctly describes the allocation group's free space
1249  *		(i.e. the highest level at which the allocation group's
1250  *		free space is not mixed in with that of any other group).
1251  *		in addition, we start the search within this level at a
1252  *		height of the dmapctl dmtree at which the nodes distinctly
1253  *		describe the allocation group's free space.  at this height,
1254  *		the allocation group's free space may be represented by 1
1255  *		or two sub-trees, depending on the allocation group size.
1256  *		we search the top nodes of these subtrees left to right for
1257  *		sufficient free space.  if sufficient free space is found,
1258  *		the subtree is searched to find the leftmost leaf that
1259  *		has free space.  once we have made it to the leaf, we
1260  *		move the search to the next lower level dmap control page
1261  *		corresponding to this leaf.  we continue down the dmap control
1262  *		pages until we find the dmap that contains or starts the
1263  *		sufficient free space and we allocate at this dmap.
1264  *
1265  *		if the allocation group size is equal to the dmap size,
1266  *		we'll start at the dmap corresponding to the allocation
1267  *		group and attempt the allocation at this level.
1268  *
1269  *		the dmap control page search is also not performed if the
1270  *		allocation group is completely free and we go to the first
1271  *		dmap of the allocation group to do the allocation.  this is
1272  *		done because the allocation group may be part (not the first
1273  *		part) of a larger binary buddy system, causing the dmap
1274  *		control pages to indicate no free space (NOFREE) within
1275  *		the allocation group.
1276  *
1277  * PARAMETERS:
1278  *	bmp	-  pointer to bmap descriptor
1279  *	agno	- allocation group number.
1280  *	nblocks	-  actual number of contiguous free blocks desired.
1281  *	l2nb	-  log2 number of contiguous free blocks desired.
1282  *	results	-  on successful return, set to the starting block number
1283  *		   of the newly allocated range.
1284  *
1285  * RETURN VALUES:
1286  *	0	- success
1287  *	-ENOSPC	- insufficient disk resources
1288  *	-EIO	- i/o error
1289  *
1290  * note: IWRITE_LOCK(ipmap) held on entry/exit;
1291  */
1292 static int
dbAllocAG(struct bmap * bmp,int agno,s64 nblocks,int l2nb,s64 * results)1293 dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, s64 * results)
1294 {
1295 	struct metapage *mp;
1296 	struct dmapctl *dcp;
1297 	int rc, ti, i, k, m, n, agperlev;
1298 	s64 blkno, lblkno;
1299 	int budmin;
1300 
1301 	/* allocation request should not be for more than the
1302 	 * allocation group size.
1303 	 */
1304 	if (l2nb > bmp->db_agl2size) {
1305 		jfs_error(bmp->db_ipbmap->i_sb,
1306 			  "allocation request is larger than the allocation group size\n");
1307 		return -EIO;
1308 	}
1309 
1310 	/* determine the starting block number of the allocation
1311 	 * group.
1312 	 */
1313 	blkno = (s64) agno << bmp->db_agl2size;
1314 
1315 	/* check if the allocation group size is the minimum allocation
1316 	 * group size or if the allocation group is completely free. if
1317 	 * the allocation group size is the minimum size of BPERDMAP (i.e.
1318 	 * 1 dmap), there is no need to search the dmap control page (below)
1319 	 * that fully describes the allocation group since the allocation
1320 	 * group is already fully described by a dmap.  in this case, we
1321 	 * just call dbAllocCtl() to search the dmap tree and allocate the
1322 	 * required space if available.
1323 	 *
1324 	 * if the allocation group is completely free, dbAllocCtl() is
1325 	 * also called to allocate the required space.  this is done for
1326 	 * two reasons.  first, it makes no sense searching the dmap control
1327 	 * pages for free space when we know that free space exists.  second,
1328 	 * the dmap control pages may indicate that the allocation group
1329 	 * has no free space if the allocation group is part (not the first
1330 	 * part) of a larger binary buddy system.
1331 	 */
1332 	if (bmp->db_agsize == BPERDMAP
1333 	    || bmp->db_agfree[agno] == bmp->db_agsize) {
1334 		rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1335 		if ((rc == -ENOSPC) &&
1336 		    (bmp->db_agfree[agno] == bmp->db_agsize)) {
1337 			printk(KERN_ERR "blkno = %Lx, blocks = %Lx\n",
1338 			       (unsigned long long) blkno,
1339 			       (unsigned long long) nblocks);
1340 			jfs_error(bmp->db_ipbmap->i_sb,
1341 				  "dbAllocCtl failed in free AG\n");
1342 		}
1343 		return (rc);
1344 	}
1345 
1346 	/* the buffer for the dmap control page that fully describes the
1347 	 * allocation group.
1348 	 */
1349 	lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, bmp->db_aglevel);
1350 	mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1351 	if (mp == NULL)
1352 		return -EIO;
1353 	dcp = (struct dmapctl *) mp->data;
1354 	budmin = dcp->budmin;
1355 
1356 	if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1357 		jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n");
1358 		release_metapage(mp);
1359 		return -EIO;
1360 	}
1361 
1362 	/* search the subtree(s) of the dmap control page that describes
1363 	 * the allocation group, looking for sufficient free space.  to begin,
1364 	 * determine how many allocation groups are represented in a dmap
1365 	 * control page at the control page level (i.e. L0, L1, L2) that
1366 	 * fully describes an allocation group. next, determine the starting
1367 	 * tree index of this allocation group within the control page.
1368 	 */
1369 	agperlev =
1370 	    (1 << (L2LPERCTL - (bmp->db_agheight << 1))) / bmp->db_agwidth;
1371 	ti = bmp->db_agstart + bmp->db_agwidth * (agno & (agperlev - 1));
1372 
1373 	/* dmap control page trees fan-out by 4 and a single allocation
1374 	 * group may be described by 1 or 2 subtrees within the ag level
1375 	 * dmap control page, depending upon the ag size. examine the ag's
1376 	 * subtrees for sufficient free space, starting with the leftmost
1377 	 * subtree.
1378 	 */
1379 	for (i = 0; i < bmp->db_agwidth; i++, ti++) {
1380 		/* is there sufficient free space ?
1381 		 */
1382 		if (l2nb > dcp->stree[ti])
1383 			continue;
1384 
1385 		/* sufficient free space found in a subtree. now search down
1386 		 * the subtree to find the leftmost leaf that describes this
1387 		 * free space.
1388 		 */
1389 		for (k = bmp->db_agheight; k > 0; k--) {
1390 			for (n = 0, m = (ti << 2) + 1; n < 4; n++) {
1391 				if (l2nb <= dcp->stree[m + n]) {
1392 					ti = m + n;
1393 					break;
1394 				}
1395 			}
1396 			if (n == 4) {
1397 				jfs_error(bmp->db_ipbmap->i_sb,
1398 					  "failed descending stree\n");
1399 				release_metapage(mp);
1400 				return -EIO;
1401 			}
1402 		}
1403 
1404 		/* determine the block number within the file system
1405 		 * that corresponds to this leaf.
1406 		 */
1407 		if (bmp->db_aglevel == 2)
1408 			blkno = 0;
1409 		else if (bmp->db_aglevel == 1)
1410 			blkno &= ~(MAXL1SIZE - 1);
1411 		else		/* bmp->db_aglevel == 0 */
1412 			blkno &= ~(MAXL0SIZE - 1);
1413 
1414 		blkno +=
1415 		    ((s64) (ti - le32_to_cpu(dcp->leafidx))) << budmin;
1416 
1417 		/* release the buffer in preparation for going down
1418 		 * the next level of dmap control pages.
1419 		 */
1420 		release_metapage(mp);
1421 
1422 		/* check if we need to continue to search down the lower
1423 		 * level dmap control pages.  we need to if the number of
1424 		 * blocks required is less than maximum number of blocks
1425 		 * described at the next lower level.
1426 		 */
1427 		if (l2nb < budmin) {
1428 
1429 			/* search the lower level dmap control pages to get
1430 			 * the starting block number of the dmap that
1431 			 * contains or starts off the free space.
1432 			 */
1433 			if ((rc =
1434 			     dbFindCtl(bmp, l2nb, bmp->db_aglevel - 1,
1435 				       &blkno))) {
1436 				if (rc == -ENOSPC) {
1437 					jfs_error(bmp->db_ipbmap->i_sb,
1438 						  "control page inconsistent\n");
1439 					return -EIO;
1440 				}
1441 				return (rc);
1442 			}
1443 		}
1444 
1445 		/* allocate the blocks.
1446 		 */
1447 		rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1448 		if (rc == -ENOSPC) {
1449 			jfs_error(bmp->db_ipbmap->i_sb,
1450 				  "unable to allocate blocks\n");
1451 			rc = -EIO;
1452 		}
1453 		return (rc);
1454 	}
1455 
1456 	/* no space in the allocation group.  release the buffer and
1457 	 * return -ENOSPC.
1458 	 */
1459 	release_metapage(mp);
1460 
1461 	return -ENOSPC;
1462 }
1463 
1464 
1465 /*
1466  * NAME:	dbAllocAny()
1467  *
1468  * FUNCTION:	attempt to allocate the specified number of contiguous
1469  *		free blocks anywhere in the file system.
1470  *
1471  *		dbAllocAny() attempts to find the sufficient free space by
1472  *		searching down the dmap control pages, starting with the
1473  *		highest level (i.e. L0, L1, L2) control page.  if free space
1474  *		large enough to satisfy the desired free space is found, the
1475  *		desired free space is allocated.
1476  *
1477  * PARAMETERS:
1478  *	bmp	-  pointer to bmap descriptor
1479  *	nblocks	 -  actual number of contiguous free blocks desired.
1480  *	l2nb	 -  log2 number of contiguous free blocks desired.
1481  *	results	-  on successful return, set to the starting block number
1482  *		   of the newly allocated range.
1483  *
1484  * RETURN VALUES:
1485  *	0	- success
1486  *	-ENOSPC	- insufficient disk resources
1487  *	-EIO	- i/o error
1488  *
1489  * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1490  */
dbAllocAny(struct bmap * bmp,s64 nblocks,int l2nb,s64 * results)1491 static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results)
1492 {
1493 	int rc;
1494 	s64 blkno = 0;
1495 
1496 	/* starting with the top level dmap control page, search
1497 	 * down the dmap control levels for sufficient free space.
1498 	 * if free space is found, dbFindCtl() returns the starting
1499 	 * block number of the dmap that contains or starts off the
1500 	 * range of free space.
1501 	 */
1502 	if ((rc = dbFindCtl(bmp, l2nb, bmp->db_maxlevel, &blkno)))
1503 		return (rc);
1504 
1505 	/* allocate the blocks.
1506 	 */
1507 	rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1508 	if (rc == -ENOSPC) {
1509 		jfs_error(bmp->db_ipbmap->i_sb, "unable to allocate blocks\n");
1510 		return -EIO;
1511 	}
1512 	return (rc);
1513 }
1514 
1515 
1516 /*
1517  * NAME:	dbDiscardAG()
1518  *
1519  * FUNCTION:	attempt to discard (TRIM) all free blocks of specific AG
1520  *
1521  *		algorithm:
1522  *		1) allocate blocks, as large as possible and save them
1523  *		   while holding IWRITE_LOCK on ipbmap
1524  *		2) trim all these saved block/length values
1525  *		3) mark the blocks free again
1526  *
1527  *		benefit:
1528  *		- we work only on one ag at some time, minimizing how long we
1529  *		  need to lock ipbmap
1530  *		- reading / writing the fs is possible most time, even on
1531  *		  trimming
1532  *
1533  *		downside:
1534  *		- we write two times to the dmapctl and dmap pages
1535  *		- but for me, this seems the best way, better ideas?
1536  *		/TR 2012
1537  *
1538  * PARAMETERS:
1539  *	ip	- pointer to in-core inode
1540  *	agno	- ag to trim
1541  *	minlen	- minimum value of contiguous blocks
1542  *
1543  * RETURN VALUES:
1544  *	s64	- actual number of blocks trimmed
1545  */
dbDiscardAG(struct inode * ip,int agno,s64 minlen)1546 s64 dbDiscardAG(struct inode *ip, int agno, s64 minlen)
1547 {
1548 	struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
1549 	struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
1550 	s64 nblocks, blkno;
1551 	u64 trimmed = 0;
1552 	int rc, l2nb;
1553 	struct super_block *sb = ipbmap->i_sb;
1554 
1555 	struct range2trim {
1556 		u64 blkno;
1557 		u64 nblocks;
1558 	} *totrim, *tt;
1559 
1560 	/* max blkno / nblocks pairs to trim */
1561 	int count = 0, range_cnt;
1562 	u64 max_ranges;
1563 
1564 	/* prevent others from writing new stuff here, while trimming */
1565 	IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
1566 
1567 	nblocks = bmp->db_agfree[agno];
1568 	max_ranges = nblocks;
1569 	do_div(max_ranges, minlen);
1570 	range_cnt = min_t(u64, max_ranges + 1, 32 * 1024);
1571 	totrim = kmalloc_array(range_cnt, sizeof(struct range2trim), GFP_NOFS);
1572 	if (totrim == NULL) {
1573 		jfs_error(bmp->db_ipbmap->i_sb, "no memory for trim array\n");
1574 		IWRITE_UNLOCK(ipbmap);
1575 		return 0;
1576 	}
1577 
1578 	tt = totrim;
1579 	while (nblocks >= minlen) {
1580 		l2nb = BLKSTOL2(nblocks);
1581 
1582 		/* 0 = okay, -EIO = fatal, -ENOSPC -> try smaller block */
1583 		rc = dbAllocAG(bmp, agno, nblocks, l2nb, &blkno);
1584 		if (rc == 0) {
1585 			tt->blkno = blkno;
1586 			tt->nblocks = nblocks;
1587 			tt++; count++;
1588 
1589 			/* the whole ag is free, trim now */
1590 			if (bmp->db_agfree[agno] == 0)
1591 				break;
1592 
1593 			/* give a hint for the next while */
1594 			nblocks = bmp->db_agfree[agno];
1595 			continue;
1596 		} else if (rc == -ENOSPC) {
1597 			/* search for next smaller log2 block */
1598 			l2nb = BLKSTOL2(nblocks) - 1;
1599 			nblocks = 1LL << l2nb;
1600 		} else {
1601 			/* Trim any already allocated blocks */
1602 			jfs_error(bmp->db_ipbmap->i_sb, "-EIO\n");
1603 			break;
1604 		}
1605 
1606 		/* check, if our trim array is full */
1607 		if (unlikely(count >= range_cnt - 1))
1608 			break;
1609 	}
1610 	IWRITE_UNLOCK(ipbmap);
1611 
1612 	tt->nblocks = 0; /* mark the current end */
1613 	for (tt = totrim; tt->nblocks != 0; tt++) {
1614 		/* when mounted with online discard, dbFree() will
1615 		 * call jfs_issue_discard() itself */
1616 		if (!(JFS_SBI(sb)->flag & JFS_DISCARD))
1617 			jfs_issue_discard(ip, tt->blkno, tt->nblocks);
1618 		dbFree(ip, tt->blkno, tt->nblocks);
1619 		trimmed += tt->nblocks;
1620 	}
1621 	kfree(totrim);
1622 
1623 	return trimmed;
1624 }
1625 
1626 /*
1627  * NAME:	dbFindCtl()
1628  *
1629  * FUNCTION:	starting at a specified dmap control page level and block
1630  *		number, search down the dmap control levels for a range of
1631  *		contiguous free blocks large enough to satisfy an allocation
1632  *		request for the specified number of free blocks.
1633  *
1634  *		if sufficient contiguous free blocks are found, this routine
1635  *		returns the starting block number within a dmap page that
1636  *		contains or starts a range of contiqious free blocks that
1637  *		is sufficient in size.
1638  *
1639  * PARAMETERS:
1640  *	bmp	-  pointer to bmap descriptor
1641  *	level	-  starting dmap control page level.
1642  *	l2nb	-  log2 number of contiguous free blocks desired.
1643  *	*blkno	-  on entry, starting block number for conducting the search.
1644  *		   on successful return, the first block within a dmap page
1645  *		   that contains or starts a range of contiguous free blocks.
1646  *
1647  * RETURN VALUES:
1648  *	0	- success
1649  *	-ENOSPC	- insufficient disk resources
1650  *	-EIO	- i/o error
1651  *
1652  * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1653  */
dbFindCtl(struct bmap * bmp,int l2nb,int level,s64 * blkno)1654 static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno)
1655 {
1656 	int rc, leafidx, lev;
1657 	s64 b, lblkno;
1658 	struct dmapctl *dcp;
1659 	int budmin;
1660 	struct metapage *mp;
1661 
1662 	/* starting at the specified dmap control page level and block
1663 	 * number, search down the dmap control levels for the starting
1664 	 * block number of a dmap page that contains or starts off
1665 	 * sufficient free blocks.
1666 	 */
1667 	for (lev = level, b = *blkno; lev >= 0; lev--) {
1668 		/* get the buffer of the dmap control page for the block
1669 		 * number and level (i.e. L0, L1, L2).
1670 		 */
1671 		lblkno = BLKTOCTL(b, bmp->db_l2nbperpage, lev);
1672 		mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1673 		if (mp == NULL)
1674 			return -EIO;
1675 		dcp = (struct dmapctl *) mp->data;
1676 		budmin = dcp->budmin;
1677 
1678 		if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1679 			jfs_error(bmp->db_ipbmap->i_sb,
1680 				  "Corrupt dmapctl page\n");
1681 			release_metapage(mp);
1682 			return -EIO;
1683 		}
1684 
1685 		/* search the tree within the dmap control page for
1686 		 * sufficient free space.  if sufficient free space is found,
1687 		 * dbFindLeaf() returns the index of the leaf at which
1688 		 * free space was found.
1689 		 */
1690 		rc = dbFindLeaf((dmtree_t *) dcp, l2nb, &leafidx);
1691 
1692 		/* release the buffer.
1693 		 */
1694 		release_metapage(mp);
1695 
1696 		/* space found ?
1697 		 */
1698 		if (rc) {
1699 			if (lev != level) {
1700 				jfs_error(bmp->db_ipbmap->i_sb,
1701 					  "dmap inconsistent\n");
1702 				return -EIO;
1703 			}
1704 			return -ENOSPC;
1705 		}
1706 
1707 		/* adjust the block number to reflect the location within
1708 		 * the dmap control page (i.e. the leaf) at which free
1709 		 * space was found.
1710 		 */
1711 		b += (((s64) leafidx) << budmin);
1712 
1713 		/* we stop the search at this dmap control page level if
1714 		 * the number of blocks required is greater than or equal
1715 		 * to the maximum number of blocks described at the next
1716 		 * (lower) level.
1717 		 */
1718 		if (l2nb >= budmin)
1719 			break;
1720 	}
1721 
1722 	*blkno = b;
1723 	return (0);
1724 }
1725 
1726 
1727 /*
1728  * NAME:	dbAllocCtl()
1729  *
1730  * FUNCTION:	attempt to allocate a specified number of contiguous
1731  *		blocks starting within a specific dmap.
1732  *
1733  *		this routine is called by higher level routines that search
1734  *		the dmap control pages above the actual dmaps for contiguous
1735  *		free space.  the result of successful searches by these
1736  *		routines are the starting block numbers within dmaps, with
1737  *		the dmaps themselves containing the desired contiguous free
1738  *		space or starting a contiguous free space of desired size
1739  *		that is made up of the blocks of one or more dmaps. these
1740  *		calls should not fail due to insufficent resources.
1741  *
1742  *		this routine is called in some cases where it is not known
1743  *		whether it will fail due to insufficient resources.  more
1744  *		specifically, this occurs when allocating from an allocation
1745  *		group whose size is equal to the number of blocks per dmap.
1746  *		in this case, the dmap control pages are not examined prior
1747  *		to calling this routine (to save pathlength) and the call
1748  *		might fail.
1749  *
1750  *		for a request size that fits within a dmap, this routine relies
1751  *		upon the dmap's dmtree to find the requested contiguous free
1752  *		space.  for request sizes that are larger than a dmap, the
1753  *		requested free space will start at the first block of the
1754  *		first dmap (i.e. blkno).
1755  *
1756  * PARAMETERS:
1757  *	bmp	-  pointer to bmap descriptor
1758  *	nblocks	 -  actual number of contiguous free blocks to allocate.
1759  *	l2nb	 -  log2 number of contiguous free blocks to allocate.
1760  *	blkno	 -  starting block number of the dmap to start the allocation
1761  *		    from.
1762  *	results	-  on successful return, set to the starting block number
1763  *		   of the newly allocated range.
1764  *
1765  * RETURN VALUES:
1766  *	0	- success
1767  *	-ENOSPC	- insufficient disk resources
1768  *	-EIO	- i/o error
1769  *
1770  * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1771  */
1772 static int
dbAllocCtl(struct bmap * bmp,s64 nblocks,int l2nb,s64 blkno,s64 * results)1773 dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results)
1774 {
1775 	int rc, nb;
1776 	s64 b, lblkno, n;
1777 	struct metapage *mp;
1778 	struct dmap *dp;
1779 
1780 	/* check if the allocation request is confined to a single dmap.
1781 	 */
1782 	if (l2nb <= L2BPERDMAP) {
1783 		/* get the buffer for the dmap.
1784 		 */
1785 		lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
1786 		mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1787 		if (mp == NULL)
1788 			return -EIO;
1789 		dp = (struct dmap *) mp->data;
1790 
1791 		/* try to allocate the blocks.
1792 		 */
1793 		rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results);
1794 		if (rc == 0)
1795 			mark_metapage_dirty(mp);
1796 
1797 		release_metapage(mp);
1798 
1799 		return (rc);
1800 	}
1801 
1802 	/* allocation request involving multiple dmaps. it must start on
1803 	 * a dmap boundary.
1804 	 */
1805 	assert((blkno & (BPERDMAP - 1)) == 0);
1806 
1807 	/* allocate the blocks dmap by dmap.
1808 	 */
1809 	for (n = nblocks, b = blkno; n > 0; n -= nb, b += nb) {
1810 		/* get the buffer for the dmap.
1811 		 */
1812 		lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1813 		mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1814 		if (mp == NULL) {
1815 			rc = -EIO;
1816 			goto backout;
1817 		}
1818 		dp = (struct dmap *) mp->data;
1819 
1820 		/* the dmap better be all free.
1821 		 */
1822 		if (dp->tree.stree[ROOT] != L2BPERDMAP) {
1823 			release_metapage(mp);
1824 			jfs_error(bmp->db_ipbmap->i_sb,
1825 				  "the dmap is not all free\n");
1826 			rc = -EIO;
1827 			goto backout;
1828 		}
1829 
1830 		/* determine how many blocks to allocate from this dmap.
1831 		 */
1832 		nb = min_t(s64, n, BPERDMAP);
1833 
1834 		/* allocate the blocks from the dmap.
1835 		 */
1836 		if ((rc = dbAllocDmap(bmp, dp, b, nb))) {
1837 			release_metapage(mp);
1838 			goto backout;
1839 		}
1840 
1841 		/* write the buffer.
1842 		 */
1843 		write_metapage(mp);
1844 	}
1845 
1846 	/* set the results (starting block number) and return.
1847 	 */
1848 	*results = blkno;
1849 	return (0);
1850 
1851 	/* something failed in handling an allocation request involving
1852 	 * multiple dmaps.  we'll try to clean up by backing out any
1853 	 * allocation that has already happened for this request.  if
1854 	 * we fail in backing out the allocation, we'll mark the file
1855 	 * system to indicate that blocks have been leaked.
1856 	 */
1857       backout:
1858 
1859 	/* try to backout the allocations dmap by dmap.
1860 	 */
1861 	for (n = nblocks - n, b = blkno; n > 0;
1862 	     n -= BPERDMAP, b += BPERDMAP) {
1863 		/* get the buffer for this dmap.
1864 		 */
1865 		lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1866 		mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1867 		if (mp == NULL) {
1868 			/* could not back out.  mark the file system
1869 			 * to indicate that we have leaked blocks.
1870 			 */
1871 			jfs_error(bmp->db_ipbmap->i_sb,
1872 				  "I/O Error: Block Leakage\n");
1873 			continue;
1874 		}
1875 		dp = (struct dmap *) mp->data;
1876 
1877 		/* free the blocks is this dmap.
1878 		 */
1879 		if (dbFreeDmap(bmp, dp, b, BPERDMAP)) {
1880 			/* could not back out.  mark the file system
1881 			 * to indicate that we have leaked blocks.
1882 			 */
1883 			release_metapage(mp);
1884 			jfs_error(bmp->db_ipbmap->i_sb, "Block Leakage\n");
1885 			continue;
1886 		}
1887 
1888 		/* write the buffer.
1889 		 */
1890 		write_metapage(mp);
1891 	}
1892 
1893 	return (rc);
1894 }
1895 
1896 
1897 /*
1898  * NAME:	dbAllocDmapLev()
1899  *
1900  * FUNCTION:	attempt to allocate a specified number of contiguous blocks
1901  *		from a specified dmap.
1902  *
1903  *		this routine checks if the contiguous blocks are available.
1904  *		if so, nblocks of blocks are allocated; otherwise, ENOSPC is
1905  *		returned.
1906  *
1907  * PARAMETERS:
1908  *	mp	-  pointer to bmap descriptor
1909  *	dp	-  pointer to dmap to attempt to allocate blocks from.
1910  *	l2nb	-  log2 number of contiguous block desired.
1911  *	nblocks	-  actual number of contiguous block desired.
1912  *	results	-  on successful return, set to the starting block number
1913  *		   of the newly allocated range.
1914  *
1915  * RETURN VALUES:
1916  *	0	- success
1917  *	-ENOSPC	- insufficient disk resources
1918  *	-EIO	- i/o error
1919  *
1920  * serialization: IREAD_LOCK(ipbmap), e.g., from dbAlloc(), or
1921  *	IWRITE_LOCK(ipbmap), e.g., dbAllocCtl(), held on entry/exit;
1922  */
1923 static int
dbAllocDmapLev(struct bmap * bmp,struct dmap * dp,int nblocks,int l2nb,s64 * results)1924 dbAllocDmapLev(struct bmap * bmp,
1925 	       struct dmap * dp, int nblocks, int l2nb, s64 * results)
1926 {
1927 	s64 blkno;
1928 	int leafidx, rc;
1929 
1930 	/* can't be more than a dmaps worth of blocks */
1931 	assert(l2nb <= L2BPERDMAP);
1932 
1933 	/* search the tree within the dmap page for sufficient
1934 	 * free space.  if sufficient free space is found, dbFindLeaf()
1935 	 * returns the index of the leaf at which free space was found.
1936 	 */
1937 	if (dbFindLeaf((dmtree_t *) & dp->tree, l2nb, &leafidx))
1938 		return -ENOSPC;
1939 
1940 	/* determine the block number within the file system corresponding
1941 	 * to the leaf at which free space was found.
1942 	 */
1943 	blkno = le64_to_cpu(dp->start) + (leafidx << L2DBWORD);
1944 
1945 	/* if not all bits of the dmap word are free, get the starting
1946 	 * bit number within the dmap word of the required string of free
1947 	 * bits and adjust the block number with this value.
1948 	 */
1949 	if (dp->tree.stree[leafidx + LEAFIND] < BUDMIN)
1950 		blkno += dbFindBits(le32_to_cpu(dp->wmap[leafidx]), l2nb);
1951 
1952 	/* allocate the blocks */
1953 	if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1954 		*results = blkno;
1955 
1956 	return (rc);
1957 }
1958 
1959 
1960 /*
1961  * NAME:	dbAllocDmap()
1962  *
1963  * FUNCTION:	adjust the disk allocation map to reflect the allocation
1964  *		of a specified block range within a dmap.
1965  *
1966  *		this routine allocates the specified blocks from the dmap
1967  *		through a call to dbAllocBits(). if the allocation of the
1968  *		block range causes the maximum string of free blocks within
1969  *		the dmap to change (i.e. the value of the root of the dmap's
1970  *		dmtree), this routine will cause this change to be reflected
1971  *		up through the appropriate levels of the dmap control pages
1972  *		by a call to dbAdjCtl() for the L0 dmap control page that
1973  *		covers this dmap.
1974  *
1975  * PARAMETERS:
1976  *	bmp	-  pointer to bmap descriptor
1977  *	dp	-  pointer to dmap to allocate the block range from.
1978  *	blkno	-  starting block number of the block to be allocated.
1979  *	nblocks	-  number of blocks to be allocated.
1980  *
1981  * RETURN VALUES:
1982  *	0	- success
1983  *	-EIO	- i/o error
1984  *
1985  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
1986  */
dbAllocDmap(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)1987 static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
1988 		       int nblocks)
1989 {
1990 	s8 oldroot;
1991 	int rc;
1992 
1993 	/* save the current value of the root (i.e. maximum free string)
1994 	 * of the dmap tree.
1995 	 */
1996 	oldroot = dp->tree.stree[ROOT];
1997 
1998 	/* allocate the specified (blocks) bits */
1999 	dbAllocBits(bmp, dp, blkno, nblocks);
2000 
2001 	/* if the root has not changed, done. */
2002 	if (dp->tree.stree[ROOT] == oldroot)
2003 		return (0);
2004 
2005 	/* root changed. bubble the change up to the dmap control pages.
2006 	 * if the adjustment of the upper level control pages fails,
2007 	 * backout the bit allocation (thus making everything consistent).
2008 	 */
2009 	if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 1, 0)))
2010 		dbFreeBits(bmp, dp, blkno, nblocks);
2011 
2012 	return (rc);
2013 }
2014 
2015 
2016 /*
2017  * NAME:	dbFreeDmap()
2018  *
2019  * FUNCTION:	adjust the disk allocation map to reflect the allocation
2020  *		of a specified block range within a dmap.
2021  *
2022  *		this routine frees the specified blocks from the dmap through
2023  *		a call to dbFreeBits(). if the deallocation of the block range
2024  *		causes the maximum string of free blocks within the dmap to
2025  *		change (i.e. the value of the root of the dmap's dmtree), this
2026  *		routine will cause this change to be reflected up through the
2027  *		appropriate levels of the dmap control pages by a call to
2028  *		dbAdjCtl() for the L0 dmap control page that covers this dmap.
2029  *
2030  * PARAMETERS:
2031  *	bmp	-  pointer to bmap descriptor
2032  *	dp	-  pointer to dmap to free the block range from.
2033  *	blkno	-  starting block number of the block to be freed.
2034  *	nblocks	-  number of blocks to be freed.
2035  *
2036  * RETURN VALUES:
2037  *	0	- success
2038  *	-EIO	- i/o error
2039  *
2040  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2041  */
dbFreeDmap(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)2042 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
2043 		      int nblocks)
2044 {
2045 	s8 oldroot;
2046 	int rc = 0, word;
2047 
2048 	/* save the current value of the root (i.e. maximum free string)
2049 	 * of the dmap tree.
2050 	 */
2051 	oldroot = dp->tree.stree[ROOT];
2052 
2053 	/* free the specified (blocks) bits */
2054 	rc = dbFreeBits(bmp, dp, blkno, nblocks);
2055 
2056 	/* if error or the root has not changed, done. */
2057 	if (rc || (dp->tree.stree[ROOT] == oldroot))
2058 		return (rc);
2059 
2060 	/* root changed. bubble the change up to the dmap control pages.
2061 	 * if the adjustment of the upper level control pages fails,
2062 	 * backout the deallocation.
2063 	 */
2064 	if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 0, 0))) {
2065 		word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
2066 
2067 		/* as part of backing out the deallocation, we will have
2068 		 * to back split the dmap tree if the deallocation caused
2069 		 * the freed blocks to become part of a larger binary buddy
2070 		 * system.
2071 		 */
2072 		if (dp->tree.stree[word] == NOFREE)
2073 			dbBackSplit((dmtree_t *) & dp->tree, word);
2074 
2075 		dbAllocBits(bmp, dp, blkno, nblocks);
2076 	}
2077 
2078 	return (rc);
2079 }
2080 
2081 
2082 /*
2083  * NAME:	dbAllocBits()
2084  *
2085  * FUNCTION:	allocate a specified block range from a dmap.
2086  *
2087  *		this routine updates the dmap to reflect the working
2088  *		state allocation of the specified block range. it directly
2089  *		updates the bits of the working map and causes the adjustment
2090  *		of the binary buddy system described by the dmap's dmtree
2091  *		leaves to reflect the bits allocated.  it also causes the
2092  *		dmap's dmtree, as a whole, to reflect the allocated range.
2093  *
2094  * PARAMETERS:
2095  *	bmp	-  pointer to bmap descriptor
2096  *	dp	-  pointer to dmap to allocate bits from.
2097  *	blkno	-  starting block number of the bits to be allocated.
2098  *	nblocks	-  number of bits to be allocated.
2099  *
2100  * RETURN VALUES: none
2101  *
2102  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2103  */
dbAllocBits(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)2104 static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2105 			int nblocks)
2106 {
2107 	int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2108 	dmtree_t *tp = (dmtree_t *) & dp->tree;
2109 	int size;
2110 	s8 *leaf;
2111 
2112 	/* pick up a pointer to the leaves of the dmap tree */
2113 	leaf = dp->tree.stree + LEAFIND;
2114 
2115 	/* determine the bit number and word within the dmap of the
2116 	 * starting block.
2117 	 */
2118 	dbitno = blkno & (BPERDMAP - 1);
2119 	word = dbitno >> L2DBWORD;
2120 
2121 	/* block range better be within the dmap */
2122 	assert(dbitno + nblocks <= BPERDMAP);
2123 
2124 	/* allocate the bits of the dmap's words corresponding to the block
2125 	 * range. not all bits of the first and last words may be contained
2126 	 * within the block range.  if this is the case, we'll work against
2127 	 * those words (i.e. partial first and/or last) on an individual basis
2128 	 * (a single pass), allocating the bits of interest by hand and
2129 	 * updating the leaf corresponding to the dmap word. a single pass
2130 	 * will be used for all dmap words fully contained within the
2131 	 * specified range.  within this pass, the bits of all fully contained
2132 	 * dmap words will be marked as free in a single shot and the leaves
2133 	 * will be updated. a single leaf may describe the free space of
2134 	 * multiple dmap words, so we may update only a subset of the actual
2135 	 * leaves corresponding to the dmap words of the block range.
2136 	 */
2137 	for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2138 		/* determine the bit number within the word and
2139 		 * the number of bits within the word.
2140 		 */
2141 		wbitno = dbitno & (DBWORD - 1);
2142 		nb = min(rembits, DBWORD - wbitno);
2143 
2144 		/* check if only part of a word is to be allocated.
2145 		 */
2146 		if (nb < DBWORD) {
2147 			/* allocate (set to 1) the appropriate bits within
2148 			 * this dmap word.
2149 			 */
2150 			dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
2151 						      >> wbitno);
2152 
2153 			/* update the leaf for this dmap word. in addition
2154 			 * to setting the leaf value to the binary buddy max
2155 			 * of the updated dmap word, dbSplit() will split
2156 			 * the binary system of the leaves if need be.
2157 			 */
2158 			dbSplit(tp, word, BUDMIN,
2159 				dbMaxBud((u8 *) & dp->wmap[word]));
2160 
2161 			word += 1;
2162 		} else {
2163 			/* one or more dmap words are fully contained
2164 			 * within the block range.  determine how many
2165 			 * words and allocate (set to 1) the bits of these
2166 			 * words.
2167 			 */
2168 			nwords = rembits >> L2DBWORD;
2169 			memset(&dp->wmap[word], (int) ONES, nwords * 4);
2170 
2171 			/* determine how many bits.
2172 			 */
2173 			nb = nwords << L2DBWORD;
2174 
2175 			/* now update the appropriate leaves to reflect
2176 			 * the allocated words.
2177 			 */
2178 			for (; nwords > 0; nwords -= nw) {
2179 				if (leaf[word] < BUDMIN) {
2180 					jfs_error(bmp->db_ipbmap->i_sb,
2181 						  "leaf page corrupt\n");
2182 					break;
2183 				}
2184 
2185 				/* determine what the leaf value should be
2186 				 * updated to as the minimum of the l2 number
2187 				 * of bits being allocated and the l2 number
2188 				 * of bits currently described by this leaf.
2189 				 */
2190 				size = min_t(int, leaf[word],
2191 					     NLSTOL2BSZ(nwords));
2192 
2193 				/* update the leaf to reflect the allocation.
2194 				 * in addition to setting the leaf value to
2195 				 * NOFREE, dbSplit() will split the binary
2196 				 * system of the leaves to reflect the current
2197 				 * allocation (size).
2198 				 */
2199 				dbSplit(tp, word, size, NOFREE);
2200 
2201 				/* get the number of dmap words handled */
2202 				nw = BUDSIZE(size, BUDMIN);
2203 				word += nw;
2204 			}
2205 		}
2206 	}
2207 
2208 	/* update the free count for this dmap */
2209 	le32_add_cpu(&dp->nfree, -nblocks);
2210 
2211 	BMAP_LOCK(bmp);
2212 
2213 	/* if this allocation group is completely free,
2214 	 * update the maximum allocation group number if this allocation
2215 	 * group is the new max.
2216 	 */
2217 	agno = blkno >> bmp->db_agl2size;
2218 	if (agno > bmp->db_maxag)
2219 		bmp->db_maxag = agno;
2220 
2221 	/* update the free count for the allocation group and map */
2222 	bmp->db_agfree[agno] -= nblocks;
2223 	bmp->db_nfree -= nblocks;
2224 
2225 	BMAP_UNLOCK(bmp);
2226 }
2227 
2228 
2229 /*
2230  * NAME:	dbFreeBits()
2231  *
2232  * FUNCTION:	free a specified block range from a dmap.
2233  *
2234  *		this routine updates the dmap to reflect the working
2235  *		state allocation of the specified block range. it directly
2236  *		updates the bits of the working map and causes the adjustment
2237  *		of the binary buddy system described by the dmap's dmtree
2238  *		leaves to reflect the bits freed.  it also causes the dmap's
2239  *		dmtree, as a whole, to reflect the deallocated range.
2240  *
2241  * PARAMETERS:
2242  *	bmp	-  pointer to bmap descriptor
2243  *	dp	-  pointer to dmap to free bits from.
2244  *	blkno	-  starting block number of the bits to be freed.
2245  *	nblocks	-  number of bits to be freed.
2246  *
2247  * RETURN VALUES: 0 for success
2248  *
2249  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2250  */
dbFreeBits(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)2251 static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2252 		       int nblocks)
2253 {
2254 	int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2255 	dmtree_t *tp = (dmtree_t *) & dp->tree;
2256 	int rc = 0;
2257 	int size;
2258 
2259 	/* determine the bit number and word within the dmap of the
2260 	 * starting block.
2261 	 */
2262 	dbitno = blkno & (BPERDMAP - 1);
2263 	word = dbitno >> L2DBWORD;
2264 
2265 	/* block range better be within the dmap.
2266 	 */
2267 	assert(dbitno + nblocks <= BPERDMAP);
2268 
2269 	/* free the bits of the dmaps words corresponding to the block range.
2270 	 * not all bits of the first and last words may be contained within
2271 	 * the block range.  if this is the case, we'll work against those
2272 	 * words (i.e. partial first and/or last) on an individual basis
2273 	 * (a single pass), freeing the bits of interest by hand and updating
2274 	 * the leaf corresponding to the dmap word. a single pass will be used
2275 	 * for all dmap words fully contained within the specified range.
2276 	 * within this pass, the bits of all fully contained dmap words will
2277 	 * be marked as free in a single shot and the leaves will be updated. a
2278 	 * single leaf may describe the free space of multiple dmap words,
2279 	 * so we may update only a subset of the actual leaves corresponding
2280 	 * to the dmap words of the block range.
2281 	 *
2282 	 * dbJoin() is used to update leaf values and will join the binary
2283 	 * buddy system of the leaves if the new leaf values indicate this
2284 	 * should be done.
2285 	 */
2286 	for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2287 		/* determine the bit number within the word and
2288 		 * the number of bits within the word.
2289 		 */
2290 		wbitno = dbitno & (DBWORD - 1);
2291 		nb = min(rembits, DBWORD - wbitno);
2292 
2293 		/* check if only part of a word is to be freed.
2294 		 */
2295 		if (nb < DBWORD) {
2296 			/* free (zero) the appropriate bits within this
2297 			 * dmap word.
2298 			 */
2299 			dp->wmap[word] &=
2300 			    cpu_to_le32(~(ONES << (DBWORD - nb)
2301 					  >> wbitno));
2302 
2303 			/* update the leaf for this dmap word.
2304 			 */
2305 			rc = dbJoin(tp, word,
2306 				    dbMaxBud((u8 *) & dp->wmap[word]));
2307 			if (rc)
2308 				return rc;
2309 
2310 			word += 1;
2311 		} else {
2312 			/* one or more dmap words are fully contained
2313 			 * within the block range.  determine how many
2314 			 * words and free (zero) the bits of these words.
2315 			 */
2316 			nwords = rembits >> L2DBWORD;
2317 			memset(&dp->wmap[word], 0, nwords * 4);
2318 
2319 			/* determine how many bits.
2320 			 */
2321 			nb = nwords << L2DBWORD;
2322 
2323 			/* now update the appropriate leaves to reflect
2324 			 * the freed words.
2325 			 */
2326 			for (; nwords > 0; nwords -= nw) {
2327 				/* determine what the leaf value should be
2328 				 * updated to as the minimum of the l2 number
2329 				 * of bits being freed and the l2 (max) number
2330 				 * of bits that can be described by this leaf.
2331 				 */
2332 				size =
2333 				    min(LITOL2BSZ
2334 					(word, L2LPERDMAP, BUDMIN),
2335 					NLSTOL2BSZ(nwords));
2336 
2337 				/* update the leaf.
2338 				 */
2339 				rc = dbJoin(tp, word, size);
2340 				if (rc)
2341 					return rc;
2342 
2343 				/* get the number of dmap words handled.
2344 				 */
2345 				nw = BUDSIZE(size, BUDMIN);
2346 				word += nw;
2347 			}
2348 		}
2349 	}
2350 
2351 	/* update the free count for this dmap.
2352 	 */
2353 	le32_add_cpu(&dp->nfree, nblocks);
2354 
2355 	BMAP_LOCK(bmp);
2356 
2357 	/* update the free count for the allocation group and
2358 	 * map.
2359 	 */
2360 	agno = blkno >> bmp->db_agl2size;
2361 	bmp->db_nfree += nblocks;
2362 	bmp->db_agfree[agno] += nblocks;
2363 
2364 	/* check if this allocation group is not completely free and
2365 	 * if it is currently the maximum (rightmost) allocation group.
2366 	 * if so, establish the new maximum allocation group number by
2367 	 * searching left for the first allocation group with allocation.
2368 	 */
2369 	if ((bmp->db_agfree[agno] == bmp->db_agsize && agno == bmp->db_maxag) ||
2370 	    (agno == bmp->db_numag - 1 &&
2371 	     bmp->db_agfree[agno] == (bmp-> db_mapsize & (BPERDMAP - 1)))) {
2372 		while (bmp->db_maxag > 0) {
2373 			bmp->db_maxag -= 1;
2374 			if (bmp->db_agfree[bmp->db_maxag] !=
2375 			    bmp->db_agsize)
2376 				break;
2377 		}
2378 
2379 		/* re-establish the allocation group preference if the
2380 		 * current preference is right of the maximum allocation
2381 		 * group.
2382 		 */
2383 		if (bmp->db_agpref > bmp->db_maxag)
2384 			bmp->db_agpref = bmp->db_maxag;
2385 	}
2386 
2387 	BMAP_UNLOCK(bmp);
2388 
2389 	return 0;
2390 }
2391 
2392 
2393 /*
2394  * NAME:	dbAdjCtl()
2395  *
2396  * FUNCTION:	adjust a dmap control page at a specified level to reflect
2397  *		the change in a lower level dmap or dmap control page's
2398  *		maximum string of free blocks (i.e. a change in the root
2399  *		of the lower level object's dmtree) due to the allocation
2400  *		or deallocation of a range of blocks with a single dmap.
2401  *
2402  *		on entry, this routine is provided with the new value of
2403  *		the lower level dmap or dmap control page root and the
2404  *		starting block number of the block range whose allocation
2405  *		or deallocation resulted in the root change.  this range
2406  *		is respresented by a single leaf of the current dmapctl
2407  *		and the leaf will be updated with this value, possibly
2408  *		causing a binary buddy system within the leaves to be
2409  *		split or joined.  the update may also cause the dmapctl's
2410  *		dmtree to be updated.
2411  *
2412  *		if the adjustment of the dmap control page, itself, causes its
2413  *		root to change, this change will be bubbled up to the next dmap
2414  *		control level by a recursive call to this routine, specifying
2415  *		the new root value and the next dmap control page level to
2416  *		be adjusted.
2417  * PARAMETERS:
2418  *	bmp	-  pointer to bmap descriptor
2419  *	blkno	-  the first block of a block range within a dmap.  it is
2420  *		   the allocation or deallocation of this block range that
2421  *		   requires the dmap control page to be adjusted.
2422  *	newval	-  the new value of the lower level dmap or dmap control
2423  *		   page root.
2424  *	alloc	-  'true' if adjustment is due to an allocation.
2425  *	level	-  current level of dmap control page (i.e. L0, L1, L2) to
2426  *		   be adjusted.
2427  *
2428  * RETURN VALUES:
2429  *	0	- success
2430  *	-EIO	- i/o error
2431  *
2432  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2433  */
2434 static int
dbAdjCtl(struct bmap * bmp,s64 blkno,int newval,int alloc,int level)2435 dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, int level)
2436 {
2437 	struct metapage *mp;
2438 	s8 oldroot;
2439 	int oldval;
2440 	s64 lblkno;
2441 	struct dmapctl *dcp;
2442 	int rc, leafno, ti;
2443 
2444 	/* get the buffer for the dmap control page for the specified
2445 	 * block number and control page level.
2446 	 */
2447 	lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, level);
2448 	mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
2449 	if (mp == NULL)
2450 		return -EIO;
2451 	dcp = (struct dmapctl *) mp->data;
2452 
2453 	if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
2454 		jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n");
2455 		release_metapage(mp);
2456 		return -EIO;
2457 	}
2458 
2459 	/* determine the leaf number corresponding to the block and
2460 	 * the index within the dmap control tree.
2461 	 */
2462 	leafno = BLKTOCTLLEAF(blkno, dcp->budmin);
2463 	ti = leafno + le32_to_cpu(dcp->leafidx);
2464 
2465 	/* save the current leaf value and the current root level (i.e.
2466 	 * maximum l2 free string described by this dmapctl).
2467 	 */
2468 	oldval = dcp->stree[ti];
2469 	oldroot = dcp->stree[ROOT];
2470 
2471 	/* check if this is a control page update for an allocation.
2472 	 * if so, update the leaf to reflect the new leaf value using
2473 	 * dbSplit(); otherwise (deallocation), use dbJoin() to update
2474 	 * the leaf with the new value.  in addition to updating the
2475 	 * leaf, dbSplit() will also split the binary buddy system of
2476 	 * the leaves, if required, and bubble new values within the
2477 	 * dmapctl tree, if required.  similarly, dbJoin() will join
2478 	 * the binary buddy system of leaves and bubble new values up
2479 	 * the dmapctl tree as required by the new leaf value.
2480 	 */
2481 	if (alloc) {
2482 		/* check if we are in the middle of a binary buddy
2483 		 * system.  this happens when we are performing the
2484 		 * first allocation out of an allocation group that
2485 		 * is part (not the first part) of a larger binary
2486 		 * buddy system.  if we are in the middle, back split
2487 		 * the system prior to calling dbSplit() which assumes
2488 		 * that it is at the front of a binary buddy system.
2489 		 */
2490 		if (oldval == NOFREE) {
2491 			rc = dbBackSplit((dmtree_t *) dcp, leafno);
2492 			if (rc) {
2493 				release_metapage(mp);
2494 				return rc;
2495 			}
2496 			oldval = dcp->stree[ti];
2497 		}
2498 		dbSplit((dmtree_t *) dcp, leafno, dcp->budmin, newval);
2499 	} else {
2500 		rc = dbJoin((dmtree_t *) dcp, leafno, newval);
2501 		if (rc) {
2502 			release_metapage(mp);
2503 			return rc;
2504 		}
2505 	}
2506 
2507 	/* check if the root of the current dmap control page changed due
2508 	 * to the update and if the current dmap control page is not at
2509 	 * the current top level (i.e. L0, L1, L2) of the map.  if so (i.e.
2510 	 * root changed and this is not the top level), call this routine
2511 	 * again (recursion) for the next higher level of the mapping to
2512 	 * reflect the change in root for the current dmap control page.
2513 	 */
2514 	if (dcp->stree[ROOT] != oldroot) {
2515 		/* are we below the top level of the map.  if so,
2516 		 * bubble the root up to the next higher level.
2517 		 */
2518 		if (level < bmp->db_maxlevel) {
2519 			/* bubble up the new root of this dmap control page to
2520 			 * the next level.
2521 			 */
2522 			if ((rc =
2523 			     dbAdjCtl(bmp, blkno, dcp->stree[ROOT], alloc,
2524 				      level + 1))) {
2525 				/* something went wrong in bubbling up the new
2526 				 * root value, so backout the changes to the
2527 				 * current dmap control page.
2528 				 */
2529 				if (alloc) {
2530 					dbJoin((dmtree_t *) dcp, leafno,
2531 					       oldval);
2532 				} else {
2533 					/* the dbJoin() above might have
2534 					 * caused a larger binary buddy system
2535 					 * to form and we may now be in the
2536 					 * middle of it.  if this is the case,
2537 					 * back split the buddies.
2538 					 */
2539 					if (dcp->stree[ti] == NOFREE)
2540 						dbBackSplit((dmtree_t *)
2541 							    dcp, leafno);
2542 					dbSplit((dmtree_t *) dcp, leafno,
2543 						dcp->budmin, oldval);
2544 				}
2545 
2546 				/* release the buffer and return the error.
2547 				 */
2548 				release_metapage(mp);
2549 				return (rc);
2550 			}
2551 		} else {
2552 			/* we're at the top level of the map. update
2553 			 * the bmap control page to reflect the size
2554 			 * of the maximum free buddy system.
2555 			 */
2556 			assert(level == bmp->db_maxlevel);
2557 			if (bmp->db_maxfreebud != oldroot) {
2558 				jfs_error(bmp->db_ipbmap->i_sb,
2559 					  "the maximum free buddy is not the old root\n");
2560 			}
2561 			bmp->db_maxfreebud = dcp->stree[ROOT];
2562 		}
2563 	}
2564 
2565 	/* write the buffer.
2566 	 */
2567 	write_metapage(mp);
2568 
2569 	return (0);
2570 }
2571 
2572 
2573 /*
2574  * NAME:	dbSplit()
2575  *
2576  * FUNCTION:	update the leaf of a dmtree with a new value, splitting
2577  *		the leaf from the binary buddy system of the dmtree's
2578  *		leaves, as required.
2579  *
2580  * PARAMETERS:
2581  *	tp	- pointer to the tree containing the leaf.
2582  *	leafno	- the number of the leaf to be updated.
2583  *	splitsz	- the size the binary buddy system starting at the leaf
2584  *		  must be split to, specified as the log2 number of blocks.
2585  *	newval	- the new value for the leaf.
2586  *
2587  * RETURN VALUES: none
2588  *
2589  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2590  */
dbSplit(dmtree_t * tp,int leafno,int splitsz,int newval)2591 static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval)
2592 {
2593 	int budsz;
2594 	int cursz;
2595 	s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2596 
2597 	/* check if the leaf needs to be split.
2598 	 */
2599 	if (leaf[leafno] > tp->dmt_budmin) {
2600 		/* the split occurs by cutting the buddy system in half
2601 		 * at the specified leaf until we reach the specified
2602 		 * size.  pick up the starting split size (current size
2603 		 * - 1 in l2) and the corresponding buddy size.
2604 		 */
2605 		cursz = leaf[leafno] - 1;
2606 		budsz = BUDSIZE(cursz, tp->dmt_budmin);
2607 
2608 		/* split until we reach the specified size.
2609 		 */
2610 		while (cursz >= splitsz) {
2611 			/* update the buddy's leaf with its new value.
2612 			 */
2613 			dbAdjTree(tp, leafno ^ budsz, cursz);
2614 
2615 			/* on to the next size and buddy.
2616 			 */
2617 			cursz -= 1;
2618 			budsz >>= 1;
2619 		}
2620 	}
2621 
2622 	/* adjust the dmap tree to reflect the specified leaf's new
2623 	 * value.
2624 	 */
2625 	dbAdjTree(tp, leafno, newval);
2626 }
2627 
2628 
2629 /*
2630  * NAME:	dbBackSplit()
2631  *
2632  * FUNCTION:	back split the binary buddy system of dmtree leaves
2633  *		that hold a specified leaf until the specified leaf
2634  *		starts its own binary buddy system.
2635  *
2636  *		the allocators typically perform allocations at the start
2637  *		of binary buddy systems and dbSplit() is used to accomplish
2638  *		any required splits.  in some cases, however, allocation
2639  *		may occur in the middle of a binary system and requires a
2640  *		back split, with the split proceeding out from the middle of
2641  *		the system (less efficient) rather than the start of the
2642  *		system (more efficient).  the cases in which a back split
2643  *		is required are rare and are limited to the first allocation
2644  *		within an allocation group which is a part (not first part)
2645  *		of a larger binary buddy system and a few exception cases
2646  *		in which a previous join operation must be backed out.
2647  *
2648  * PARAMETERS:
2649  *	tp	- pointer to the tree containing the leaf.
2650  *	leafno	- the number of the leaf to be updated.
2651  *
2652  * RETURN VALUES: none
2653  *
2654  * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2655  */
dbBackSplit(dmtree_t * tp,int leafno)2656 static int dbBackSplit(dmtree_t * tp, int leafno)
2657 {
2658 	int budsz, bud, w, bsz, size;
2659 	int cursz;
2660 	s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2661 
2662 	/* leaf should be part (not first part) of a binary
2663 	 * buddy system.
2664 	 */
2665 	assert(leaf[leafno] == NOFREE);
2666 
2667 	/* the back split is accomplished by iteratively finding the leaf
2668 	 * that starts the buddy system that contains the specified leaf and
2669 	 * splitting that system in two.  this iteration continues until
2670 	 * the specified leaf becomes the start of a buddy system.
2671 	 *
2672 	 * determine maximum possible l2 size for the specified leaf.
2673 	 */
2674 	size =
2675 	    LITOL2BSZ(leafno, le32_to_cpu(tp->dmt_l2nleafs),
2676 		      tp->dmt_budmin);
2677 
2678 	/* determine the number of leaves covered by this size.  this
2679 	 * is the buddy size that we will start with as we search for
2680 	 * the buddy system that contains the specified leaf.
2681 	 */
2682 	budsz = BUDSIZE(size, tp->dmt_budmin);
2683 
2684 	/* back split.
2685 	 */
2686 	while (leaf[leafno] == NOFREE) {
2687 		/* find the leftmost buddy leaf.
2688 		 */
2689 		for (w = leafno, bsz = budsz;; bsz <<= 1,
2690 		     w = (w < bud) ? w : bud) {
2691 			if (bsz >= le32_to_cpu(tp->dmt_nleafs)) {
2692 				jfs_err("JFS: block map error in dbBackSplit");
2693 				return -EIO;
2694 			}
2695 
2696 			/* determine the buddy.
2697 			 */
2698 			bud = w ^ bsz;
2699 
2700 			/* check if this buddy is the start of the system.
2701 			 */
2702 			if (leaf[bud] != NOFREE) {
2703 				/* split the leaf at the start of the
2704 				 * system in two.
2705 				 */
2706 				cursz = leaf[bud] - 1;
2707 				dbSplit(tp, bud, cursz, cursz);
2708 				break;
2709 			}
2710 		}
2711 	}
2712 
2713 	if (leaf[leafno] != size) {
2714 		jfs_err("JFS: wrong leaf value in dbBackSplit");
2715 		return -EIO;
2716 	}
2717 	return 0;
2718 }
2719 
2720 
2721 /*
2722  * NAME:	dbJoin()
2723  *
2724  * FUNCTION:	update the leaf of a dmtree with a new value, joining
2725  *		the leaf with other leaves of the dmtree into a multi-leaf
2726  *		binary buddy system, as required.
2727  *
2728  * PARAMETERS:
2729  *	tp	- pointer to the tree containing the leaf.
2730  *	leafno	- the number of the leaf to be updated.
2731  *	newval	- the new value for the leaf.
2732  *
2733  * RETURN VALUES: none
2734  */
dbJoin(dmtree_t * tp,int leafno,int newval)2735 static int dbJoin(dmtree_t * tp, int leafno, int newval)
2736 {
2737 	int budsz, buddy;
2738 	s8 *leaf;
2739 
2740 	/* can the new leaf value require a join with other leaves ?
2741 	 */
2742 	if (newval >= tp->dmt_budmin) {
2743 		/* pickup a pointer to the leaves of the tree.
2744 		 */
2745 		leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2746 
2747 		/* try to join the specified leaf into a large binary
2748 		 * buddy system.  the join proceeds by attempting to join
2749 		 * the specified leafno with its buddy (leaf) at new value.
2750 		 * if the join occurs, we attempt to join the left leaf
2751 		 * of the joined buddies with its buddy at new value + 1.
2752 		 * we continue to join until we find a buddy that cannot be
2753 		 * joined (does not have a value equal to the size of the
2754 		 * last join) or until all leaves have been joined into a
2755 		 * single system.
2756 		 *
2757 		 * get the buddy size (number of words covered) of
2758 		 * the new value.
2759 		 */
2760 		budsz = BUDSIZE(newval, tp->dmt_budmin);
2761 
2762 		/* try to join.
2763 		 */
2764 		while (budsz < le32_to_cpu(tp->dmt_nleafs)) {
2765 			/* get the buddy leaf.
2766 			 */
2767 			buddy = leafno ^ budsz;
2768 
2769 			/* if the leaf's new value is greater than its
2770 			 * buddy's value, we join no more.
2771 			 */
2772 			if (newval > leaf[buddy])
2773 				break;
2774 
2775 			/* It shouldn't be less */
2776 			if (newval < leaf[buddy])
2777 				return -EIO;
2778 
2779 			/* check which (leafno or buddy) is the left buddy.
2780 			 * the left buddy gets to claim the blocks resulting
2781 			 * from the join while the right gets to claim none.
2782 			 * the left buddy is also eligible to participate in
2783 			 * a join at the next higher level while the right
2784 			 * is not.
2785 			 *
2786 			 */
2787 			if (leafno < buddy) {
2788 				/* leafno is the left buddy.
2789 				 */
2790 				dbAdjTree(tp, buddy, NOFREE);
2791 			} else {
2792 				/* buddy is the left buddy and becomes
2793 				 * leafno.
2794 				 */
2795 				dbAdjTree(tp, leafno, NOFREE);
2796 				leafno = buddy;
2797 			}
2798 
2799 			/* on to try the next join.
2800 			 */
2801 			newval += 1;
2802 			budsz <<= 1;
2803 		}
2804 	}
2805 
2806 	/* update the leaf value.
2807 	 */
2808 	dbAdjTree(tp, leafno, newval);
2809 
2810 	return 0;
2811 }
2812 
2813 
2814 /*
2815  * NAME:	dbAdjTree()
2816  *
2817  * FUNCTION:	update a leaf of a dmtree with a new value, adjusting
2818  *		the dmtree, as required, to reflect the new leaf value.
2819  *		the combination of any buddies must already be done before
2820  *		this is called.
2821  *
2822  * PARAMETERS:
2823  *	tp	- pointer to the tree to be adjusted.
2824  *	leafno	- the number of the leaf to be updated.
2825  *	newval	- the new value for the leaf.
2826  *
2827  * RETURN VALUES: none
2828  */
dbAdjTree(dmtree_t * tp,int leafno,int newval)2829 static void dbAdjTree(dmtree_t * tp, int leafno, int newval)
2830 {
2831 	int lp, pp, k;
2832 	int max;
2833 
2834 	/* pick up the index of the leaf for this leafno.
2835 	 */
2836 	lp = leafno + le32_to_cpu(tp->dmt_leafidx);
2837 
2838 	/* is the current value the same as the old value ?  if so,
2839 	 * there is nothing to do.
2840 	 */
2841 	if (tp->dmt_stree[lp] == newval)
2842 		return;
2843 
2844 	/* set the new value.
2845 	 */
2846 	tp->dmt_stree[lp] = newval;
2847 
2848 	/* bubble the new value up the tree as required.
2849 	 */
2850 	for (k = 0; k < le32_to_cpu(tp->dmt_height); k++) {
2851 		/* get the index of the first leaf of the 4 leaf
2852 		 * group containing the specified leaf (leafno).
2853 		 */
2854 		lp = ((lp - 1) & ~0x03) + 1;
2855 
2856 		/* get the index of the parent of this 4 leaf group.
2857 		 */
2858 		pp = (lp - 1) >> 2;
2859 
2860 		/* determine the maximum of the 4 leaves.
2861 		 */
2862 		max = TREEMAX(&tp->dmt_stree[lp]);
2863 
2864 		/* if the maximum of the 4 is the same as the
2865 		 * parent's value, we're done.
2866 		 */
2867 		if (tp->dmt_stree[pp] == max)
2868 			break;
2869 
2870 		/* parent gets new value.
2871 		 */
2872 		tp->dmt_stree[pp] = max;
2873 
2874 		/* parent becomes leaf for next go-round.
2875 		 */
2876 		lp = pp;
2877 	}
2878 }
2879 
2880 
2881 /*
2882  * NAME:	dbFindLeaf()
2883  *
2884  * FUNCTION:	search a dmtree_t for sufficient free blocks, returning
2885  *		the index of a leaf describing the free blocks if
2886  *		sufficient free blocks are found.
2887  *
2888  *		the search starts at the top of the dmtree_t tree and
2889  *		proceeds down the tree to the leftmost leaf with sufficient
2890  *		free space.
2891  *
2892  * PARAMETERS:
2893  *	tp	- pointer to the tree to be searched.
2894  *	l2nb	- log2 number of free blocks to search for.
2895  *	leafidx	- return pointer to be set to the index of the leaf
2896  *		  describing at least l2nb free blocks if sufficient
2897  *		  free blocks are found.
2898  *
2899  * RETURN VALUES:
2900  *	0	- success
2901  *	-ENOSPC	- insufficient free blocks.
2902  */
dbFindLeaf(dmtree_t * tp,int l2nb,int * leafidx)2903 static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx)
2904 {
2905 	int ti, n = 0, k, x = 0;
2906 
2907 	/* first check the root of the tree to see if there is
2908 	 * sufficient free space.
2909 	 */
2910 	if (l2nb > tp->dmt_stree[ROOT])
2911 		return -ENOSPC;
2912 
2913 	/* sufficient free space available. now search down the tree
2914 	 * starting at the next level for the leftmost leaf that
2915 	 * describes sufficient free space.
2916 	 */
2917 	for (k = le32_to_cpu(tp->dmt_height), ti = 1;
2918 	     k > 0; k--, ti = ((ti + n) << 2) + 1) {
2919 		/* search the four nodes at this level, starting from
2920 		 * the left.
2921 		 */
2922 		for (x = ti, n = 0; n < 4; n++) {
2923 			/* sufficient free space found.  move to the next
2924 			 * level (or quit if this is the last level).
2925 			 */
2926 			if (l2nb <= tp->dmt_stree[x + n])
2927 				break;
2928 		}
2929 
2930 		/* better have found something since the higher
2931 		 * levels of the tree said it was here.
2932 		 */
2933 		assert(n < 4);
2934 	}
2935 
2936 	/* set the return to the leftmost leaf describing sufficient
2937 	 * free space.
2938 	 */
2939 	*leafidx = x + n - le32_to_cpu(tp->dmt_leafidx);
2940 
2941 	return (0);
2942 }
2943 
2944 
2945 /*
2946  * NAME:	dbFindBits()
2947  *
2948  * FUNCTION:	find a specified number of binary buddy free bits within a
2949  *		dmap bitmap word value.
2950  *
2951  *		this routine searches the bitmap value for (1 << l2nb) free
2952  *		bits at (1 << l2nb) alignments within the value.
2953  *
2954  * PARAMETERS:
2955  *	word	-  dmap bitmap word value.
2956  *	l2nb	-  number of free bits specified as a log2 number.
2957  *
2958  * RETURN VALUES:
2959  *	starting bit number of free bits.
2960  */
dbFindBits(u32 word,int l2nb)2961 static int dbFindBits(u32 word, int l2nb)
2962 {
2963 	int bitno, nb;
2964 	u32 mask;
2965 
2966 	/* get the number of bits.
2967 	 */
2968 	nb = 1 << l2nb;
2969 	assert(nb <= DBWORD);
2970 
2971 	/* complement the word so we can use a mask (i.e. 0s represent
2972 	 * free bits) and compute the mask.
2973 	 */
2974 	word = ~word;
2975 	mask = ONES << (DBWORD - nb);
2976 
2977 	/* scan the word for nb free bits at nb alignments.
2978 	 */
2979 	for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) {
2980 		if ((mask & word) == mask)
2981 			break;
2982 	}
2983 
2984 	ASSERT(bitno < 32);
2985 
2986 	/* return the bit number.
2987 	 */
2988 	return (bitno);
2989 }
2990 
2991 
2992 /*
2993  * NAME:	dbMaxBud(u8 *cp)
2994  *
2995  * FUNCTION:	determine the largest binary buddy string of free
2996  *		bits within 32-bits of the map.
2997  *
2998  * PARAMETERS:
2999  *	cp	-  pointer to the 32-bit value.
3000  *
3001  * RETURN VALUES:
3002  *	largest binary buddy of free bits within a dmap word.
3003  */
dbMaxBud(u8 * cp)3004 static int dbMaxBud(u8 * cp)
3005 {
3006 	signed char tmp1, tmp2;
3007 
3008 	/* check if the wmap word is all free. if so, the
3009 	 * free buddy size is BUDMIN.
3010 	 */
3011 	if (*((uint *) cp) == 0)
3012 		return (BUDMIN);
3013 
3014 	/* check if the wmap word is half free. if so, the
3015 	 * free buddy size is BUDMIN-1.
3016 	 */
3017 	if (*((u16 *) cp) == 0 || *((u16 *) cp + 1) == 0)
3018 		return (BUDMIN - 1);
3019 
3020 	/* not all free or half free. determine the free buddy
3021 	 * size thru table lookup using quarters of the wmap word.
3022 	 */
3023 	tmp1 = max(budtab[cp[2]], budtab[cp[3]]);
3024 	tmp2 = max(budtab[cp[0]], budtab[cp[1]]);
3025 	return (max(tmp1, tmp2));
3026 }
3027 
3028 
3029 /*
3030  * NAME:	cnttz(uint word)
3031  *
3032  * FUNCTION:	determine the number of trailing zeros within a 32-bit
3033  *		value.
3034  *
3035  * PARAMETERS:
3036  *	value	-  32-bit value to be examined.
3037  *
3038  * RETURN VALUES:
3039  *	count of trailing zeros
3040  */
cnttz(u32 word)3041 static int cnttz(u32 word)
3042 {
3043 	int n;
3044 
3045 	for (n = 0; n < 32; n++, word >>= 1) {
3046 		if (word & 0x01)
3047 			break;
3048 	}
3049 
3050 	return (n);
3051 }
3052 
3053 
3054 /*
3055  * NAME:	cntlz(u32 value)
3056  *
3057  * FUNCTION:	determine the number of leading zeros within a 32-bit
3058  *		value.
3059  *
3060  * PARAMETERS:
3061  *	value	-  32-bit value to be examined.
3062  *
3063  * RETURN VALUES:
3064  *	count of leading zeros
3065  */
cntlz(u32 value)3066 static int cntlz(u32 value)
3067 {
3068 	int n;
3069 
3070 	for (n = 0; n < 32; n++, value <<= 1) {
3071 		if (value & HIGHORDER)
3072 			break;
3073 	}
3074 	return (n);
3075 }
3076 
3077 
3078 /*
3079  * NAME:	blkstol2(s64 nb)
3080  *
3081  * FUNCTION:	convert a block count to its log2 value. if the block
3082  *		count is not a l2 multiple, it is rounded up to the next
3083  *		larger l2 multiple.
3084  *
3085  * PARAMETERS:
3086  *	nb	-  number of blocks
3087  *
3088  * RETURN VALUES:
3089  *	log2 number of blocks
3090  */
blkstol2(s64 nb)3091 static int blkstol2(s64 nb)
3092 {
3093 	int l2nb;
3094 	s64 mask;		/* meant to be signed */
3095 
3096 	mask = (s64) 1 << (64 - 1);
3097 
3098 	/* count the leading bits.
3099 	 */
3100 	for (l2nb = 0; l2nb < 64; l2nb++, mask >>= 1) {
3101 		/* leading bit found.
3102 		 */
3103 		if (nb & mask) {
3104 			/* determine the l2 value.
3105 			 */
3106 			l2nb = (64 - 1) - l2nb;
3107 
3108 			/* check if we need to round up.
3109 			 */
3110 			if (~mask & nb)
3111 				l2nb++;
3112 
3113 			return (l2nb);
3114 		}
3115 	}
3116 	assert(0);
3117 	return 0;		/* fix compiler warning */
3118 }
3119 
3120 
3121 /*
3122  * NAME:	dbAllocBottomUp()
3123  *
3124  * FUNCTION:	alloc the specified block range from the working block
3125  *		allocation map.
3126  *
3127  *		the blocks will be alloc from the working map one dmap
3128  *		at a time.
3129  *
3130  * PARAMETERS:
3131  *	ip	-  pointer to in-core inode;
3132  *	blkno	-  starting block number to be freed.
3133  *	nblocks	-  number of blocks to be freed.
3134  *
3135  * RETURN VALUES:
3136  *	0	- success
3137  *	-EIO	- i/o error
3138  */
dbAllocBottomUp(struct inode * ip,s64 blkno,s64 nblocks)3139 int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks)
3140 {
3141 	struct metapage *mp;
3142 	struct dmap *dp;
3143 	int nb, rc;
3144 	s64 lblkno, rem;
3145 	struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
3146 	struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
3147 
3148 	IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
3149 
3150 	/* block to be allocated better be within the mapsize. */
3151 	ASSERT(nblocks <= bmp->db_mapsize - blkno);
3152 
3153 	/*
3154 	 * allocate the blocks a dmap at a time.
3155 	 */
3156 	mp = NULL;
3157 	for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
3158 		/* release previous dmap if any */
3159 		if (mp) {
3160 			write_metapage(mp);
3161 		}
3162 
3163 		/* get the buffer for the current dmap. */
3164 		lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
3165 		mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
3166 		if (mp == NULL) {
3167 			IREAD_UNLOCK(ipbmap);
3168 			return -EIO;
3169 		}
3170 		dp = (struct dmap *) mp->data;
3171 
3172 		/* determine the number of blocks to be allocated from
3173 		 * this dmap.
3174 		 */
3175 		nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
3176 
3177 		/* allocate the blocks. */
3178 		if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) {
3179 			release_metapage(mp);
3180 			IREAD_UNLOCK(ipbmap);
3181 			return (rc);
3182 		}
3183 	}
3184 
3185 	/* write the last buffer. */
3186 	write_metapage(mp);
3187 
3188 	IREAD_UNLOCK(ipbmap);
3189 
3190 	return (0);
3191 }
3192 
3193 
dbAllocDmapBU(struct bmap * bmp,struct dmap * dp,s64 blkno,int nblocks)3194 static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
3195 			 int nblocks)
3196 {
3197 	int rc;
3198 	int dbitno, word, rembits, nb, nwords, wbitno, agno;
3199 	s8 oldroot;
3200 	struct dmaptree *tp = (struct dmaptree *) & dp->tree;
3201 
3202 	/* save the current value of the root (i.e. maximum free string)
3203 	 * of the dmap tree.
3204 	 */
3205 	oldroot = tp->stree[ROOT];
3206 
3207 	/* determine the bit number and word within the dmap of the
3208 	 * starting block.
3209 	 */
3210 	dbitno = blkno & (BPERDMAP - 1);
3211 	word = dbitno >> L2DBWORD;
3212 
3213 	/* block range better be within the dmap */
3214 	assert(dbitno + nblocks <= BPERDMAP);
3215 
3216 	/* allocate the bits of the dmap's words corresponding to the block
3217 	 * range. not all bits of the first and last words may be contained
3218 	 * within the block range.  if this is the case, we'll work against
3219 	 * those words (i.e. partial first and/or last) on an individual basis
3220 	 * (a single pass), allocating the bits of interest by hand and
3221 	 * updating the leaf corresponding to the dmap word. a single pass
3222 	 * will be used for all dmap words fully contained within the
3223 	 * specified range.  within this pass, the bits of all fully contained
3224 	 * dmap words will be marked as free in a single shot and the leaves
3225 	 * will be updated. a single leaf may describe the free space of
3226 	 * multiple dmap words, so we may update only a subset of the actual
3227 	 * leaves corresponding to the dmap words of the block range.
3228 	 */
3229 	for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
3230 		/* determine the bit number within the word and
3231 		 * the number of bits within the word.
3232 		 */
3233 		wbitno = dbitno & (DBWORD - 1);
3234 		nb = min(rembits, DBWORD - wbitno);
3235 
3236 		/* check if only part of a word is to be allocated.
3237 		 */
3238 		if (nb < DBWORD) {
3239 			/* allocate (set to 1) the appropriate bits within
3240 			 * this dmap word.
3241 			 */
3242 			dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
3243 						      >> wbitno);
3244 
3245 			word++;
3246 		} else {
3247 			/* one or more dmap words are fully contained
3248 			 * within the block range.  determine how many
3249 			 * words and allocate (set to 1) the bits of these
3250 			 * words.
3251 			 */
3252 			nwords = rembits >> L2DBWORD;
3253 			memset(&dp->wmap[word], (int) ONES, nwords * 4);
3254 
3255 			/* determine how many bits */
3256 			nb = nwords << L2DBWORD;
3257 			word += nwords;
3258 		}
3259 	}
3260 
3261 	/* update the free count for this dmap */
3262 	le32_add_cpu(&dp->nfree, -nblocks);
3263 
3264 	/* reconstruct summary tree */
3265 	dbInitDmapTree(dp);
3266 
3267 	BMAP_LOCK(bmp);
3268 
3269 	/* if this allocation group is completely free,
3270 	 * update the highest active allocation group number
3271 	 * if this allocation group is the new max.
3272 	 */
3273 	agno = blkno >> bmp->db_agl2size;
3274 	if (agno > bmp->db_maxag)
3275 		bmp->db_maxag = agno;
3276 
3277 	/* update the free count for the allocation group and map */
3278 	bmp->db_agfree[agno] -= nblocks;
3279 	bmp->db_nfree -= nblocks;
3280 
3281 	BMAP_UNLOCK(bmp);
3282 
3283 	/* if the root has not changed, done. */
3284 	if (tp->stree[ROOT] == oldroot)
3285 		return (0);
3286 
3287 	/* root changed. bubble the change up to the dmap control pages.
3288 	 * if the adjustment of the upper level control pages fails,
3289 	 * backout the bit allocation (thus making everything consistent).
3290 	 */
3291 	if ((rc = dbAdjCtl(bmp, blkno, tp->stree[ROOT], 1, 0)))
3292 		dbFreeBits(bmp, dp, blkno, nblocks);
3293 
3294 	return (rc);
3295 }
3296 
3297 
3298 /*
3299  * NAME:	dbExtendFS()
3300  *
3301  * FUNCTION:	extend bmap from blkno for nblocks;
3302  *		dbExtendFS() updates bmap ready for dbAllocBottomUp();
3303  *
3304  * L2
3305  *  |
3306  *   L1---------------------------------L1
3307  *    |					 |
3308  *     L0---------L0---------L0		  L0---------L0---------L0
3309  *      |	   |	      |		   |	      |		 |
3310  *	 d0,...,dn  d0,...,dn  d0,...,dn    d0,...,dn  d0,...,dn  d0,.,dm;
3311  * L2L1L0d0,...,dnL0d0,...,dnL0d0,...,dnL1L0d0,...,dnL0d0,...,dnL0d0,..dm
3312  *
3313  * <---old---><----------------------------extend----------------------->
3314  */
dbExtendFS(struct inode * ipbmap,s64 blkno,s64 nblocks)3315 int dbExtendFS(struct inode *ipbmap, s64 blkno,	s64 nblocks)
3316 {
3317 	struct jfs_sb_info *sbi = JFS_SBI(ipbmap->i_sb);
3318 	int nbperpage = sbi->nbperpage;
3319 	int i, i0 = true, j, j0 = true, k, n;
3320 	s64 newsize;
3321 	s64 p;
3322 	struct metapage *mp, *l2mp, *l1mp = NULL, *l0mp = NULL;
3323 	struct dmapctl *l2dcp, *l1dcp, *l0dcp;
3324 	struct dmap *dp;
3325 	s8 *l0leaf, *l1leaf, *l2leaf;
3326 	struct bmap *bmp = sbi->bmap;
3327 	int agno, l2agsize, oldl2agsize;
3328 	s64 ag_rem;
3329 
3330 	newsize = blkno + nblocks;
3331 
3332 	jfs_info("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld",
3333 		 (long long) blkno, (long long) nblocks, (long long) newsize);
3334 
3335 	/*
3336 	 *	initialize bmap control page.
3337 	 *
3338 	 * all the data in bmap control page should exclude
3339 	 * the mkfs hidden dmap page.
3340 	 */
3341 
3342 	/* update mapsize */
3343 	bmp->db_mapsize = newsize;
3344 	bmp->db_maxlevel = BMAPSZTOLEV(bmp->db_mapsize);
3345 
3346 	/* compute new AG size */
3347 	l2agsize = dbGetL2AGSize(newsize);
3348 	oldl2agsize = bmp->db_agl2size;
3349 
3350 	bmp->db_agl2size = l2agsize;
3351 	bmp->db_agsize = 1 << l2agsize;
3352 
3353 	/* compute new number of AG */
3354 	agno = bmp->db_numag;
3355 	bmp->db_numag = newsize >> l2agsize;
3356 	bmp->db_numag += ((u32) newsize % (u32) bmp->db_agsize) ? 1 : 0;
3357 
3358 	/*
3359 	 *	reconfigure db_agfree[]
3360 	 * from old AG configuration to new AG configuration;
3361 	 *
3362 	 * coalesce contiguous k (newAGSize/oldAGSize) AGs;
3363 	 * i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn;
3364 	 * note: new AG size = old AG size * (2**x).
3365 	 */
3366 	if (l2agsize == oldl2agsize)
3367 		goto extend;
3368 	k = 1 << (l2agsize - oldl2agsize);
3369 	ag_rem = bmp->db_agfree[0];	/* save agfree[0] */
3370 	for (i = 0, n = 0; i < agno; n++) {
3371 		bmp->db_agfree[n] = 0;	/* init collection point */
3372 
3373 		/* coalesce contiguous k AGs; */
3374 		for (j = 0; j < k && i < agno; j++, i++) {
3375 			/* merge AGi to AGn */
3376 			bmp->db_agfree[n] += bmp->db_agfree[i];
3377 		}
3378 	}
3379 	bmp->db_agfree[0] += ag_rem;	/* restore agfree[0] */
3380 
3381 	for (; n < MAXAG; n++)
3382 		bmp->db_agfree[n] = 0;
3383 
3384 	/*
3385 	 * update highest active ag number
3386 	 */
3387 
3388 	bmp->db_maxag = bmp->db_maxag / k;
3389 
3390 	/*
3391 	 *	extend bmap
3392 	 *
3393 	 * update bit maps and corresponding level control pages;
3394 	 * global control page db_nfree, db_agfree[agno], db_maxfreebud;
3395 	 */
3396       extend:
3397 	/* get L2 page */
3398 	p = BMAPBLKNO + nbperpage;	/* L2 page */
3399 	l2mp = read_metapage(ipbmap, p, PSIZE, 0);
3400 	if (!l2mp) {
3401 		jfs_error(ipbmap->i_sb, "L2 page could not be read\n");
3402 		return -EIO;
3403 	}
3404 	l2dcp = (struct dmapctl *) l2mp->data;
3405 
3406 	/* compute start L1 */
3407 	k = blkno >> L2MAXL1SIZE;
3408 	l2leaf = l2dcp->stree + CTLLEAFIND + k;
3409 	p = BLKTOL1(blkno, sbi->l2nbperpage);	/* L1 page */
3410 
3411 	/*
3412 	 * extend each L1 in L2
3413 	 */
3414 	for (; k < LPERCTL; k++, p += nbperpage) {
3415 		/* get L1 page */
3416 		if (j0) {
3417 			/* read in L1 page: (blkno & (MAXL1SIZE - 1)) */
3418 			l1mp = read_metapage(ipbmap, p, PSIZE, 0);
3419 			if (l1mp == NULL)
3420 				goto errout;
3421 			l1dcp = (struct dmapctl *) l1mp->data;
3422 
3423 			/* compute start L0 */
3424 			j = (blkno & (MAXL1SIZE - 1)) >> L2MAXL0SIZE;
3425 			l1leaf = l1dcp->stree + CTLLEAFIND + j;
3426 			p = BLKTOL0(blkno, sbi->l2nbperpage);
3427 			j0 = false;
3428 		} else {
3429 			/* assign/init L1 page */
3430 			l1mp = get_metapage(ipbmap, p, PSIZE, 0);
3431 			if (l1mp == NULL)
3432 				goto errout;
3433 
3434 			l1dcp = (struct dmapctl *) l1mp->data;
3435 
3436 			/* compute start L0 */
3437 			j = 0;
3438 			l1leaf = l1dcp->stree + CTLLEAFIND;
3439 			p += nbperpage;	/* 1st L0 of L1.k */
3440 		}
3441 
3442 		/*
3443 		 * extend each L0 in L1
3444 		 */
3445 		for (; j < LPERCTL; j++) {
3446 			/* get L0 page */
3447 			if (i0) {
3448 				/* read in L0 page: (blkno & (MAXL0SIZE - 1)) */
3449 
3450 				l0mp = read_metapage(ipbmap, p, PSIZE, 0);
3451 				if (l0mp == NULL)
3452 					goto errout;
3453 				l0dcp = (struct dmapctl *) l0mp->data;
3454 
3455 				/* compute start dmap */
3456 				i = (blkno & (MAXL0SIZE - 1)) >>
3457 				    L2BPERDMAP;
3458 				l0leaf = l0dcp->stree + CTLLEAFIND + i;
3459 				p = BLKTODMAP(blkno,
3460 					      sbi->l2nbperpage);
3461 				i0 = false;
3462 			} else {
3463 				/* assign/init L0 page */
3464 				l0mp = get_metapage(ipbmap, p, PSIZE, 0);
3465 				if (l0mp == NULL)
3466 					goto errout;
3467 
3468 				l0dcp = (struct dmapctl *) l0mp->data;
3469 
3470 				/* compute start dmap */
3471 				i = 0;
3472 				l0leaf = l0dcp->stree + CTLLEAFIND;
3473 				p += nbperpage;	/* 1st dmap of L0.j */
3474 			}
3475 
3476 			/*
3477 			 * extend each dmap in L0
3478 			 */
3479 			for (; i < LPERCTL; i++) {
3480 				/*
3481 				 * reconstruct the dmap page, and
3482 				 * initialize corresponding parent L0 leaf
3483 				 */
3484 				if ((n = blkno & (BPERDMAP - 1))) {
3485 					/* read in dmap page: */
3486 					mp = read_metapage(ipbmap, p,
3487 							   PSIZE, 0);
3488 					if (mp == NULL)
3489 						goto errout;
3490 					n = min(nblocks, (s64)BPERDMAP - n);
3491 				} else {
3492 					/* assign/init dmap page */
3493 					mp = read_metapage(ipbmap, p,
3494 							   PSIZE, 0);
3495 					if (mp == NULL)
3496 						goto errout;
3497 
3498 					n = min_t(s64, nblocks, BPERDMAP);
3499 				}
3500 
3501 				dp = (struct dmap *) mp->data;
3502 				*l0leaf = dbInitDmap(dp, blkno, n);
3503 
3504 				bmp->db_nfree += n;
3505 				agno = le64_to_cpu(dp->start) >> l2agsize;
3506 				bmp->db_agfree[agno] += n;
3507 
3508 				write_metapage(mp);
3509 
3510 				l0leaf++;
3511 				p += nbperpage;
3512 
3513 				blkno += n;
3514 				nblocks -= n;
3515 				if (nblocks == 0)
3516 					break;
3517 			}	/* for each dmap in a L0 */
3518 
3519 			/*
3520 			 * build current L0 page from its leaves, and
3521 			 * initialize corresponding parent L1 leaf
3522 			 */
3523 			*l1leaf = dbInitDmapCtl(l0dcp, 0, ++i);
3524 			write_metapage(l0mp);
3525 			l0mp = NULL;
3526 
3527 			if (nblocks)
3528 				l1leaf++;	/* continue for next L0 */
3529 			else {
3530 				/* more than 1 L0 ? */
3531 				if (j > 0)
3532 					break;	/* build L1 page */
3533 				else {
3534 					/* summarize in global bmap page */
3535 					bmp->db_maxfreebud = *l1leaf;
3536 					release_metapage(l1mp);
3537 					release_metapage(l2mp);
3538 					goto finalize;
3539 				}
3540 			}
3541 		}		/* for each L0 in a L1 */
3542 
3543 		/*
3544 		 * build current L1 page from its leaves, and
3545 		 * initialize corresponding parent L2 leaf
3546 		 */
3547 		*l2leaf = dbInitDmapCtl(l1dcp, 1, ++j);
3548 		write_metapage(l1mp);
3549 		l1mp = NULL;
3550 
3551 		if (nblocks)
3552 			l2leaf++;	/* continue for next L1 */
3553 		else {
3554 			/* more than 1 L1 ? */
3555 			if (k > 0)
3556 				break;	/* build L2 page */
3557 			else {
3558 				/* summarize in global bmap page */
3559 				bmp->db_maxfreebud = *l2leaf;
3560 				release_metapage(l2mp);
3561 				goto finalize;
3562 			}
3563 		}
3564 	}			/* for each L1 in a L2 */
3565 
3566 	jfs_error(ipbmap->i_sb, "function has not returned as expected\n");
3567 errout:
3568 	if (l0mp)
3569 		release_metapage(l0mp);
3570 	if (l1mp)
3571 		release_metapage(l1mp);
3572 	release_metapage(l2mp);
3573 	return -EIO;
3574 
3575 	/*
3576 	 *	finalize bmap control page
3577 	 */
3578 finalize:
3579 
3580 	return 0;
3581 }
3582 
3583 
3584 /*
3585  *	dbFinalizeBmap()
3586  */
dbFinalizeBmap(struct inode * ipbmap)3587 void dbFinalizeBmap(struct inode *ipbmap)
3588 {
3589 	struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
3590 	int actags, inactags, l2nl;
3591 	s64 ag_rem, actfree, inactfree, avgfree;
3592 	int i, n;
3593 
3594 	/*
3595 	 *	finalize bmap control page
3596 	 */
3597 //finalize:
3598 	/*
3599 	 * compute db_agpref: preferred ag to allocate from
3600 	 * (the leftmost ag with average free space in it);
3601 	 */
3602 //agpref:
3603 	/* get the number of active ags and inactive ags */
3604 	actags = bmp->db_maxag + 1;
3605 	inactags = bmp->db_numag - actags;
3606 	ag_rem = bmp->db_mapsize & (bmp->db_agsize - 1);	/* ??? */
3607 
3608 	/* determine how many blocks are in the inactive allocation
3609 	 * groups. in doing this, we must account for the fact that
3610 	 * the rightmost group might be a partial group (i.e. file
3611 	 * system size is not a multiple of the group size).
3612 	 */
3613 	inactfree = (inactags && ag_rem) ?
3614 	    ((inactags - 1) << bmp->db_agl2size) + ag_rem
3615 	    : inactags << bmp->db_agl2size;
3616 
3617 	/* determine how many free blocks are in the active
3618 	 * allocation groups plus the average number of free blocks
3619 	 * within the active ags.
3620 	 */
3621 	actfree = bmp->db_nfree - inactfree;
3622 	avgfree = (u32) actfree / (u32) actags;
3623 
3624 	/* if the preferred allocation group has not average free space.
3625 	 * re-establish the preferred group as the leftmost
3626 	 * group with average free space.
3627 	 */
3628 	if (bmp->db_agfree[bmp->db_agpref] < avgfree) {
3629 		for (bmp->db_agpref = 0; bmp->db_agpref < actags;
3630 		     bmp->db_agpref++) {
3631 			if (bmp->db_agfree[bmp->db_agpref] >= avgfree)
3632 				break;
3633 		}
3634 		if (bmp->db_agpref >= bmp->db_numag) {
3635 			jfs_error(ipbmap->i_sb,
3636 				  "cannot find ag with average freespace\n");
3637 		}
3638 	}
3639 
3640 	/*
3641 	 * compute db_aglevel, db_agheight, db_width, db_agstart:
3642 	 * an ag is covered in aglevel dmapctl summary tree,
3643 	 * at agheight level height (from leaf) with agwidth number of nodes
3644 	 * each, which starts at agstart index node of the smmary tree node
3645 	 * array;
3646 	 */
3647 	bmp->db_aglevel = BMAPSZTOLEV(bmp->db_agsize);
3648 	l2nl =
3649 	    bmp->db_agl2size - (L2BPERDMAP + bmp->db_aglevel * L2LPERCTL);
3650 	bmp->db_agheight = l2nl >> 1;
3651 	bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheight << 1));
3652 	for (i = 5 - bmp->db_agheight, bmp->db_agstart = 0, n = 1; i > 0;
3653 	     i--) {
3654 		bmp->db_agstart += n;
3655 		n <<= 2;
3656 	}
3657 
3658 }
3659 
3660 
3661 /*
3662  * NAME:	dbInitDmap()/ujfs_idmap_page()
3663  *
3664  * FUNCTION:	initialize working/persistent bitmap of the dmap page
3665  *		for the specified number of blocks:
3666  *
3667  *		at entry, the bitmaps had been initialized as free (ZEROS);
3668  *		The number of blocks will only account for the actually
3669  *		existing blocks. Blocks which don't actually exist in
3670  *		the aggregate will be marked as allocated (ONES);
3671  *
3672  * PARAMETERS:
3673  *	dp	- pointer to page of map
3674  *	nblocks	- number of blocks this page
3675  *
3676  * RETURNS: NONE
3677  */
dbInitDmap(struct dmap * dp,s64 Blkno,int nblocks)3678 static int dbInitDmap(struct dmap * dp, s64 Blkno, int nblocks)
3679 {
3680 	int blkno, w, b, r, nw, nb, i;
3681 
3682 	/* starting block number within the dmap */
3683 	blkno = Blkno & (BPERDMAP - 1);
3684 
3685 	if (blkno == 0) {
3686 		dp->nblocks = dp->nfree = cpu_to_le32(nblocks);
3687 		dp->start = cpu_to_le64(Blkno);
3688 
3689 		if (nblocks == BPERDMAP) {
3690 			memset(&dp->wmap[0], 0, LPERDMAP * 4);
3691 			memset(&dp->pmap[0], 0, LPERDMAP * 4);
3692 			goto initTree;
3693 		}
3694 	} else {
3695 		le32_add_cpu(&dp->nblocks, nblocks);
3696 		le32_add_cpu(&dp->nfree, nblocks);
3697 	}
3698 
3699 	/* word number containing start block number */
3700 	w = blkno >> L2DBWORD;
3701 
3702 	/*
3703 	 * free the bits corresponding to the block range (ZEROS):
3704 	 * note: not all bits of the first and last words may be contained
3705 	 * within the block range.
3706 	 */
3707 	for (r = nblocks; r > 0; r -= nb, blkno += nb) {
3708 		/* number of bits preceding range to be freed in the word */
3709 		b = blkno & (DBWORD - 1);
3710 		/* number of bits to free in the word */
3711 		nb = min(r, DBWORD - b);
3712 
3713 		/* is partial word to be freed ? */
3714 		if (nb < DBWORD) {
3715 			/* free (set to 0) from the bitmap word */
3716 			dp->wmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3717 						     >> b));
3718 			dp->pmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3719 						     >> b));
3720 
3721 			/* skip the word freed */
3722 			w++;
3723 		} else {
3724 			/* free (set to 0) contiguous bitmap words */
3725 			nw = r >> L2DBWORD;
3726 			memset(&dp->wmap[w], 0, nw * 4);
3727 			memset(&dp->pmap[w], 0, nw * 4);
3728 
3729 			/* skip the words freed */
3730 			nb = nw << L2DBWORD;
3731 			w += nw;
3732 		}
3733 	}
3734 
3735 	/*
3736 	 * mark bits following the range to be freed (non-existing
3737 	 * blocks) as allocated (ONES)
3738 	 */
3739 
3740 	if (blkno == BPERDMAP)
3741 		goto initTree;
3742 
3743 	/* the first word beyond the end of existing blocks */
3744 	w = blkno >> L2DBWORD;
3745 
3746 	/* does nblocks fall on a 32-bit boundary ? */
3747 	b = blkno & (DBWORD - 1);
3748 	if (b) {
3749 		/* mark a partial word allocated */
3750 		dp->wmap[w] = dp->pmap[w] = cpu_to_le32(ONES >> b);
3751 		w++;
3752 	}
3753 
3754 	/* set the rest of the words in the page to allocated (ONES) */
3755 	for (i = w; i < LPERDMAP; i++)
3756 		dp->pmap[i] = dp->wmap[i] = cpu_to_le32(ONES);
3757 
3758 	/*
3759 	 * init tree
3760 	 */
3761       initTree:
3762 	return (dbInitDmapTree(dp));
3763 }
3764 
3765 
3766 /*
3767  * NAME:	dbInitDmapTree()/ujfs_complete_dmap()
3768  *
3769  * FUNCTION:	initialize summary tree of the specified dmap:
3770  *
3771  *		at entry, bitmap of the dmap has been initialized;
3772  *
3773  * PARAMETERS:
3774  *	dp	- dmap to complete
3775  *	blkno	- starting block number for this dmap
3776  *	treemax	- will be filled in with max free for this dmap
3777  *
3778  * RETURNS:	max free string at the root of the tree
3779  */
dbInitDmapTree(struct dmap * dp)3780 static int dbInitDmapTree(struct dmap * dp)
3781 {
3782 	struct dmaptree *tp;
3783 	s8 *cp;
3784 	int i;
3785 
3786 	/* init fixed info of tree */
3787 	tp = &dp->tree;
3788 	tp->nleafs = cpu_to_le32(LPERDMAP);
3789 	tp->l2nleafs = cpu_to_le32(L2LPERDMAP);
3790 	tp->leafidx = cpu_to_le32(LEAFIND);
3791 	tp->height = cpu_to_le32(4);
3792 	tp->budmin = BUDMIN;
3793 
3794 	/* init each leaf from corresponding wmap word:
3795 	 * note: leaf is set to NOFREE(-1) if all blocks of corresponding
3796 	 * bitmap word are allocated.
3797 	 */
3798 	cp = tp->stree + le32_to_cpu(tp->leafidx);
3799 	for (i = 0; i < LPERDMAP; i++)
3800 		*cp++ = dbMaxBud((u8 *) & dp->wmap[i]);
3801 
3802 	/* build the dmap's binary buddy summary tree */
3803 	return (dbInitTree(tp));
3804 }
3805 
3806 
3807 /*
3808  * NAME:	dbInitTree()/ujfs_adjtree()
3809  *
3810  * FUNCTION:	initialize binary buddy summary tree of a dmap or dmapctl.
3811  *
3812  *		at entry, the leaves of the tree has been initialized
3813  *		from corresponding bitmap word or root of summary tree
3814  *		of the child control page;
3815  *		configure binary buddy system at the leaf level, then
3816  *		bubble up the values of the leaf nodes up the tree.
3817  *
3818  * PARAMETERS:
3819  *	cp	- Pointer to the root of the tree
3820  *	l2leaves- Number of leaf nodes as a power of 2
3821  *	l2min	- Number of blocks that can be covered by a leaf
3822  *		  as a power of 2
3823  *
3824  * RETURNS: max free string at the root of the tree
3825  */
dbInitTree(struct dmaptree * dtp)3826 static int dbInitTree(struct dmaptree * dtp)
3827 {
3828 	int l2max, l2free, bsize, nextb, i;
3829 	int child, parent, nparent;
3830 	s8 *tp, *cp, *cp1;
3831 
3832 	tp = dtp->stree;
3833 
3834 	/* Determine the maximum free string possible for the leaves */
3835 	l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin;
3836 
3837 	/*
3838 	 * configure the leaf levevl into binary buddy system
3839 	 *
3840 	 * Try to combine buddies starting with a buddy size of 1
3841 	 * (i.e. two leaves). At a buddy size of 1 two buddy leaves
3842 	 * can be combined if both buddies have a maximum free of l2min;
3843 	 * the combination will result in the left-most buddy leaf having
3844 	 * a maximum free of l2min+1.
3845 	 * After processing all buddies for a given size, process buddies
3846 	 * at the next higher buddy size (i.e. current size * 2) and
3847 	 * the next maximum free (current free + 1).
3848 	 * This continues until the maximum possible buddy combination
3849 	 * yields maximum free.
3850 	 */
3851 	for (l2free = dtp->budmin, bsize = 1; l2free < l2max;
3852 	     l2free++, bsize = nextb) {
3853 		/* get next buddy size == current buddy pair size */
3854 		nextb = bsize << 1;
3855 
3856 		/* scan each adjacent buddy pair at current buddy size */
3857 		for (i = 0, cp = tp + le32_to_cpu(dtp->leafidx);
3858 		     i < le32_to_cpu(dtp->nleafs);
3859 		     i += nextb, cp += nextb) {
3860 			/* coalesce if both adjacent buddies are max free */
3861 			if (*cp == l2free && *(cp + bsize) == l2free) {
3862 				*cp = l2free + 1;	/* left take right */
3863 				*(cp + bsize) = -1;	/* right give left */
3864 			}
3865 		}
3866 	}
3867 
3868 	/*
3869 	 * bubble summary information of leaves up the tree.
3870 	 *
3871 	 * Starting at the leaf node level, the four nodes described by
3872 	 * the higher level parent node are compared for a maximum free and
3873 	 * this maximum becomes the value of the parent node.
3874 	 * when all lower level nodes are processed in this fashion then
3875 	 * move up to the next level (parent becomes a lower level node) and
3876 	 * continue the process for that level.
3877 	 */
3878 	for (child = le32_to_cpu(dtp->leafidx),
3879 	     nparent = le32_to_cpu(dtp->nleafs) >> 2;
3880 	     nparent > 0; nparent >>= 2, child = parent) {
3881 		/* get index of 1st node of parent level */
3882 		parent = (child - 1) >> 2;
3883 
3884 		/* set the value of the parent node as the maximum
3885 		 * of the four nodes of the current level.
3886 		 */
3887 		for (i = 0, cp = tp + child, cp1 = tp + parent;
3888 		     i < nparent; i++, cp += 4, cp1++)
3889 			*cp1 = TREEMAX(cp);
3890 	}
3891 
3892 	return (*tp);
3893 }
3894 
3895 
3896 /*
3897  *	dbInitDmapCtl()
3898  *
3899  * function: initialize dmapctl page
3900  */
dbInitDmapCtl(struct dmapctl * dcp,int level,int i)3901 static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i)
3902 {				/* start leaf index not covered by range */
3903 	s8 *cp;
3904 
3905 	dcp->nleafs = cpu_to_le32(LPERCTL);
3906 	dcp->l2nleafs = cpu_to_le32(L2LPERCTL);
3907 	dcp->leafidx = cpu_to_le32(CTLLEAFIND);
3908 	dcp->height = cpu_to_le32(5);
3909 	dcp->budmin = L2BPERDMAP + L2LPERCTL * level;
3910 
3911 	/*
3912 	 * initialize the leaves of current level that were not covered
3913 	 * by the specified input block range (i.e. the leaves have no
3914 	 * low level dmapctl or dmap).
3915 	 */
3916 	cp = &dcp->stree[CTLLEAFIND + i];
3917 	for (; i < LPERCTL; i++)
3918 		*cp++ = NOFREE;
3919 
3920 	/* build the dmap's binary buddy summary tree */
3921 	return (dbInitTree((struct dmaptree *) dcp));
3922 }
3923 
3924 
3925 /*
3926  * NAME:	dbGetL2AGSize()/ujfs_getagl2size()
3927  *
3928  * FUNCTION:	Determine log2(allocation group size) from aggregate size
3929  *
3930  * PARAMETERS:
3931  *	nblocks	- Number of blocks in aggregate
3932  *
3933  * RETURNS: log2(allocation group size) in aggregate blocks
3934  */
dbGetL2AGSize(s64 nblocks)3935 static int dbGetL2AGSize(s64 nblocks)
3936 {
3937 	s64 sz;
3938 	s64 m;
3939 	int l2sz;
3940 
3941 	if (nblocks < BPERDMAP * MAXAG)
3942 		return (L2BPERDMAP);
3943 
3944 	/* round up aggregate size to power of 2 */
3945 	m = ((u64) 1 << (64 - 1));
3946 	for (l2sz = 64; l2sz >= 0; l2sz--, m >>= 1) {
3947 		if (m & nblocks)
3948 			break;
3949 	}
3950 
3951 	sz = (s64) 1 << l2sz;
3952 	if (sz < nblocks)
3953 		l2sz += 1;
3954 
3955 	/* agsize = roundupSize/max_number_of_ag */
3956 	return (l2sz - L2MAXAG);
3957 }
3958 
3959 
3960 /*
3961  * NAME:	dbMapFileSizeToMapSize()
3962  *
3963  * FUNCTION:	compute number of blocks the block allocation map file
3964  *		can cover from the map file size;
3965  *
3966  * RETURNS:	Number of blocks which can be covered by this block map file;
3967  */
3968 
3969 /*
3970  * maximum number of map pages at each level including control pages
3971  */
3972 #define MAXL0PAGES	(1 + LPERCTL)
3973 #define MAXL1PAGES	(1 + LPERCTL * MAXL0PAGES)
3974 
3975 /*
3976  * convert number of map pages to the zero origin top dmapctl level
3977  */
3978 #define BMAPPGTOLEV(npages)	\
3979 	(((npages) <= 3 + MAXL0PAGES) ? 0 : \
3980 	 ((npages) <= 2 + MAXL1PAGES) ? 1 : 2)
3981 
dbMapFileSizeToMapSize(struct inode * ipbmap)3982 s64 dbMapFileSizeToMapSize(struct inode * ipbmap)
3983 {
3984 	struct super_block *sb = ipbmap->i_sb;
3985 	s64 nblocks;
3986 	s64 npages, ndmaps;
3987 	int level, i;
3988 	int complete, factor;
3989 
3990 	nblocks = ipbmap->i_size >> JFS_SBI(sb)->l2bsize;
3991 	npages = nblocks >> JFS_SBI(sb)->l2nbperpage;
3992 	level = BMAPPGTOLEV(npages);
3993 
3994 	/* At each level, accumulate the number of dmap pages covered by
3995 	 * the number of full child levels below it;
3996 	 * repeat for the last incomplete child level.
3997 	 */
3998 	ndmaps = 0;
3999 	npages--;		/* skip the first global control page */
4000 	/* skip higher level control pages above top level covered by map */
4001 	npages -= (2 - level);
4002 	npages--;		/* skip top level's control page */
4003 	for (i = level; i >= 0; i--) {
4004 		factor =
4005 		    (i == 2) ? MAXL1PAGES : ((i == 1) ? MAXL0PAGES : 1);
4006 		complete = (u32) npages / factor;
4007 		ndmaps += complete * ((i == 2) ? LPERCTL * LPERCTL :
4008 				      ((i == 1) ? LPERCTL : 1));
4009 
4010 		/* pages in last/incomplete child */
4011 		npages = (u32) npages % factor;
4012 		/* skip incomplete child's level control page */
4013 		npages--;
4014 	}
4015 
4016 	/* convert the number of dmaps into the number of blocks
4017 	 * which can be covered by the dmaps;
4018 	 */
4019 	nblocks = ndmaps << L2BPERDMAP;
4020 
4021 	return (nblocks);
4022 }
4023