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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Copyright (C) International Business Machines Corp., 2000-2004
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
Dave Kleikamp63f83c92006-10-02 09:55:27 -05006 * the Free Software Foundation; either version 2 of the License, or
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 * (at your option) any later version.
Dave Kleikamp63f83c92006-10-02 09:55:27 -05008 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07009 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
12 * the GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
Dave Kleikamp63f83c92006-10-02 09:55:27 -050015 * along with this program; if not, write to the Free Software
Linus Torvalds1da177e2005-04-16 15:20:36 -070016 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17 */
18
19#include <linux/fs.h>
20#include "jfs_incore.h"
21#include "jfs_superblock.h"
22#include "jfs_dmap.h"
23#include "jfs_imap.h"
24#include "jfs_lock.h"
25#include "jfs_metapage.h"
26#include "jfs_debug.h"
27
28/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070029 * SERIALIZATION of the Block Allocation Map.
30 *
31 * the working state of the block allocation map is accessed in
32 * two directions:
Dave Kleikamp63f83c92006-10-02 09:55:27 -050033 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070034 * 1) allocation and free requests that start at the dmap
35 * level and move up through the dmap control pages (i.e.
36 * the vast majority of requests).
Linus Torvalds1da177e2005-04-16 15:20:36 -070037 *
Dave Kleikamp63f83c92006-10-02 09:55:27 -050038 * 2) allocation requests that start at dmap control page
39 * level and work down towards the dmaps.
40 *
41 * the serialization scheme used here is as follows.
42 *
43 * requests which start at the bottom are serialized against each
44 * other through buffers and each requests holds onto its buffers
45 * as it works it way up from a single dmap to the required level
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 * of dmap control page.
47 * requests that start at the top are serialized against each other
48 * and request that start from the bottom by the multiple read/single
49 * write inode lock of the bmap inode. requests starting at the top
50 * take this lock in write mode while request starting at the bottom
51 * take the lock in read mode. a single top-down request may proceed
Dave Kleikamp63f83c92006-10-02 09:55:27 -050052 * exclusively while multiple bottoms-up requests may proceed
53 * simultaneously (under the protection of busy buffers).
54 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070055 * in addition to information found in dmaps and dmap control pages,
56 * the working state of the block allocation map also includes read/
57 * write information maintained in the bmap descriptor (i.e. total
58 * free block count, allocation group level free block counts).
59 * a single exclusive lock (BMAP_LOCK) is used to guard this information
60 * in the face of multiple-bottoms up requests.
61 * (lock ordering: IREAD_LOCK, BMAP_LOCK);
Dave Kleikamp63f83c92006-10-02 09:55:27 -050062 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 * accesses to the persistent state of the block allocation map (limited
64 * to the persistent bitmaps in dmaps) is guarded by (busy) buffers.
65 */
66
Ingo Molnar1de87442006-01-24 15:22:50 -060067#define BMAP_LOCK_INIT(bmp) mutex_init(&bmp->db_bmaplock)
68#define BMAP_LOCK(bmp) mutex_lock(&bmp->db_bmaplock)
69#define BMAP_UNLOCK(bmp) mutex_unlock(&bmp->db_bmaplock)
Linus Torvalds1da177e2005-04-16 15:20:36 -070070
71/*
72 * forward references
73 */
74static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
75 int nblocks);
76static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval);
Dave Kleikampb6a47fd2005-10-11 09:06:59 -050077static int dbBackSplit(dmtree_t * tp, int leafno);
Dave Kleikamp56d12542005-07-15 09:43:36 -050078static int dbJoin(dmtree_t * tp, int leafno, int newval);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079static void dbAdjTree(dmtree_t * tp, int leafno, int newval);
80static int dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc,
81 int level);
82static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results);
83static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
84 int nblocks);
85static int dbAllocNear(struct bmap * bmp, struct dmap * dp, s64 blkno,
86 int nblocks,
87 int l2nb, s64 * results);
88static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
89 int nblocks);
90static int dbAllocDmapLev(struct bmap * bmp, struct dmap * dp, int nblocks,
91 int l2nb,
92 s64 * results);
93static int dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb,
94 s64 * results);
95static int dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno,
96 s64 * results);
97static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks);
98static int dbFindBits(u32 word, int l2nb);
99static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno);
100static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx);
Dave Kleikamp56d12542005-07-15 09:43:36 -0500101static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
102 int nblocks);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
104 int nblocks);
105static int dbMaxBud(u8 * cp);
106s64 dbMapFileSizeToMapSize(struct inode *ipbmap);
107static int blkstol2(s64 nb);
108
109static int cntlz(u32 value);
110static int cnttz(u32 word);
111
112static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
113 int nblocks);
114static int dbInitDmap(struct dmap * dp, s64 blkno, int nblocks);
115static int dbInitDmapTree(struct dmap * dp);
116static int dbInitTree(struct dmaptree * dtp);
117static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i);
118static int dbGetL2AGSize(s64 nblocks);
119
120/*
121 * buddy table
122 *
Dave Kleikamp63f83c92006-10-02 09:55:27 -0500123 * table used for determining buddy sizes within characters of
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 * dmap bitmap words. the characters themselves serve as indexes
125 * into the table, with the table elements yielding the maximum
126 * binary buddy of free bits within the character.
127 */
Arjan van de Ven4d5dbd02005-11-29 08:28:58 -0600128static const s8 budtab[256] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
130 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
131 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
132 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
133 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
134 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
135 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
136 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
137 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
138 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
139 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
140 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
141 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
142 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
143 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
144 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1
145};
146
147
148/*
Dave Kleikamp63f83c92006-10-02 09:55:27 -0500149 * NAME: dbMount()
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 *
151 * FUNCTION: initializate the block allocation map.
152 *
153 * memory is allocated for the in-core bmap descriptor and
154 * the in-core descriptor is initialized from disk.
155 *
156 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500157 * ipbmap - pointer to in-core inode for the block map.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158 *
159 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500160 * 0 - success
161 * -ENOMEM - insufficient memory
162 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 */
164int dbMount(struct inode *ipbmap)
165{
166 struct bmap *bmp;
167 struct dbmap_disk *dbmp_le;
168 struct metapage *mp;
169 int i;
170
171 /*
172 * allocate/initialize the in-memory bmap descriptor
173 */
174 /* allocate memory for the in-memory bmap descriptor */
175 bmp = kmalloc(sizeof(struct bmap), GFP_KERNEL);
176 if (bmp == NULL)
177 return -ENOMEM;
178
179 /* read the on-disk bmap descriptor. */
180 mp = read_metapage(ipbmap,
181 BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
182 PSIZE, 0);
183 if (mp == NULL) {
184 kfree(bmp);
185 return -EIO;
186 }
187
188 /* copy the on-disk bmap descriptor to its in-memory version. */
189 dbmp_le = (struct dbmap_disk *) mp->data;
190 bmp->db_mapsize = le64_to_cpu(dbmp_le->dn_mapsize);
191 bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree);
192 bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage);
193 bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag);
194 bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel);
195 bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag);
196 bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref);
197 bmp->db_aglevel = le32_to_cpu(dbmp_le->dn_aglevel);
198 bmp->db_agheigth = le32_to_cpu(dbmp_le->dn_agheigth);
199 bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);
200 bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart);
201 bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size);
202 for (i = 0; i < MAXAG; i++)
203 bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]);
204 bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize);
205 bmp->db_maxfreebud = dbmp_le->dn_maxfreebud;
206
207 /* release the buffer. */
208 release_metapage(mp);
209
210 /* bind the bmap inode and the bmap descriptor to each other. */
211 bmp->db_ipbmap = ipbmap;
212 JFS_SBI(ipbmap->i_sb)->bmap = bmp;
213
214 memset(bmp->db_active, 0, sizeof(bmp->db_active));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215
216 /*
217 * allocate/initialize the bmap lock
218 */
219 BMAP_LOCK_INIT(bmp);
220
221 return (0);
222}
223
224
225/*
Dave Kleikamp63f83c92006-10-02 09:55:27 -0500226 * NAME: dbUnmount()
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 *
228 * FUNCTION: terminate the block allocation map in preparation for
229 * file system unmount.
230 *
Dave Kleikamp63f83c92006-10-02 09:55:27 -0500231 * the in-core bmap descriptor is written to disk and
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 * the memory for this descriptor is freed.
233 *
234 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500235 * ipbmap - pointer to in-core inode for the block map.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 *
237 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500238 * 0 - success
239 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 */
241int dbUnmount(struct inode *ipbmap, int mounterror)
242{
243 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244
245 if (!(mounterror || isReadOnly(ipbmap)))
246 dbSync(ipbmap);
247
248 /*
249 * Invalidate the page cache buffers
250 */
251 truncate_inode_pages(ipbmap->i_mapping, 0);
252
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 /* free the memory for the in-memory bmap. */
254 kfree(bmp);
255
256 return (0);
257}
258
259/*
260 * dbSync()
261 */
262int dbSync(struct inode *ipbmap)
263{
264 struct dbmap_disk *dbmp_le;
265 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
266 struct metapage *mp;
267 int i;
268
269 /*
270 * write bmap global control page
271 */
272 /* get the buffer for the on-disk bmap descriptor. */
273 mp = read_metapage(ipbmap,
274 BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
275 PSIZE, 0);
276 if (mp == NULL) {
277 jfs_err("dbSync: read_metapage failed!");
278 return -EIO;
279 }
280 /* copy the in-memory version of the bmap to the on-disk version */
281 dbmp_le = (struct dbmap_disk *) mp->data;
282 dbmp_le->dn_mapsize = cpu_to_le64(bmp->db_mapsize);
283 dbmp_le->dn_nfree = cpu_to_le64(bmp->db_nfree);
284 dbmp_le->dn_l2nbperpage = cpu_to_le32(bmp->db_l2nbperpage);
285 dbmp_le->dn_numag = cpu_to_le32(bmp->db_numag);
286 dbmp_le->dn_maxlevel = cpu_to_le32(bmp->db_maxlevel);
287 dbmp_le->dn_maxag = cpu_to_le32(bmp->db_maxag);
288 dbmp_le->dn_agpref = cpu_to_le32(bmp->db_agpref);
289 dbmp_le->dn_aglevel = cpu_to_le32(bmp->db_aglevel);
290 dbmp_le->dn_agheigth = cpu_to_le32(bmp->db_agheigth);
291 dbmp_le->dn_agwidth = cpu_to_le32(bmp->db_agwidth);
292 dbmp_le->dn_agstart = cpu_to_le32(bmp->db_agstart);
293 dbmp_le->dn_agl2size = cpu_to_le32(bmp->db_agl2size);
294 for (i = 0; i < MAXAG; i++)
295 dbmp_le->dn_agfree[i] = cpu_to_le64(bmp->db_agfree[i]);
296 dbmp_le->dn_agsize = cpu_to_le64(bmp->db_agsize);
297 dbmp_le->dn_maxfreebud = bmp->db_maxfreebud;
298
299 /* write the buffer */
300 write_metapage(mp);
301
302 /*
303 * write out dirty pages of bmap
304 */
OGAWA Hirofumi28fd1292006-01-08 01:02:14 -0800305 filemap_write_and_wait(ipbmap->i_mapping);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 diWriteSpecial(ipbmap, 0);
308
309 return (0);
310}
311
312
313/*
Dave Kleikamp63f83c92006-10-02 09:55:27 -0500314 * NAME: dbFree()
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 *
316 * FUNCTION: free the specified block range from the working block
317 * allocation map.
318 *
319 * the blocks will be free from the working map one dmap
320 * at a time.
321 *
322 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500323 * ip - pointer to in-core inode;
324 * blkno - starting block number to be freed.
325 * nblocks - number of blocks to be freed.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 *
327 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500328 * 0 - success
329 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 */
331int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
332{
333 struct metapage *mp;
334 struct dmap *dp;
335 int nb, rc;
336 s64 lblkno, rem;
337 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
338 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
339
Dave Kleikamp82d5b9a2007-01-09 14:14:48 -0600340 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341
342 /* block to be freed better be within the mapsize. */
343 if (unlikely((blkno == 0) || (blkno + nblocks > bmp->db_mapsize))) {
344 IREAD_UNLOCK(ipbmap);
345 printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
346 (unsigned long long) blkno,
347 (unsigned long long) nblocks);
348 jfs_error(ip->i_sb,
349 "dbFree: block to be freed is outside the map");
350 return -EIO;
351 }
352
353 /*
354 * free the blocks a dmap at a time.
355 */
356 mp = NULL;
357 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
358 /* release previous dmap if any */
359 if (mp) {
360 write_metapage(mp);
361 }
362
363 /* get the buffer for the current dmap. */
364 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
365 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
366 if (mp == NULL) {
367 IREAD_UNLOCK(ipbmap);
368 return -EIO;
369 }
370 dp = (struct dmap *) mp->data;
371
372 /* determine the number of blocks to be freed from
373 * this dmap.
374 */
375 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
376
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377 /* free the blocks. */
378 if ((rc = dbFreeDmap(bmp, dp, blkno, nb))) {
Dave Kleikamp56d12542005-07-15 09:43:36 -0500379 jfs_error(ip->i_sb, "dbFree: error in block map\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 release_metapage(mp);
381 IREAD_UNLOCK(ipbmap);
382 return (rc);
383 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 }
385
386 /* write the last buffer. */
387 write_metapage(mp);
388
389 IREAD_UNLOCK(ipbmap);
390
391 return (0);
392}
393
394
395/*
396 * NAME: dbUpdatePMap()
397 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500398 * FUNCTION: update the allocation state (free or allocate) of the
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 * specified block range in the persistent block allocation map.
Dave Kleikamp63f83c92006-10-02 09:55:27 -0500400 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 * the blocks will be updated in the persistent map one
402 * dmap at a time.
403 *
404 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500405 * ipbmap - pointer to in-core inode for the block map.
406 * free - 'true' if block range is to be freed from the persistent
407 * map; 'false' if it is to be allocated.
408 * blkno - starting block number of the range.
409 * nblocks - number of contiguous blocks in the range.
410 * tblk - transaction block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411 *
412 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500413 * 0 - success
414 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 */
416int
417dbUpdatePMap(struct inode *ipbmap,
418 int free, s64 blkno, s64 nblocks, struct tblock * tblk)
419{
420 int nblks, dbitno, wbitno, rbits;
421 int word, nbits, nwords;
422 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
423 s64 lblkno, rem, lastlblkno;
424 u32 mask;
425 struct dmap *dp;
426 struct metapage *mp;
427 struct jfs_log *log;
428 int lsn, difft, diffp;
Dave Kleikamp7fab4792005-05-02 12:25:02 -0600429 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430
431 /* the blocks better be within the mapsize. */
432 if (blkno + nblocks > bmp->db_mapsize) {
433 printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
434 (unsigned long long) blkno,
435 (unsigned long long) nblocks);
436 jfs_error(ipbmap->i_sb,
437 "dbUpdatePMap: blocks are outside the map");
438 return -EIO;
439 }
440
441 /* compute delta of transaction lsn from log syncpt */
442 lsn = tblk->lsn;
443 log = (struct jfs_log *) JFS_SBI(tblk->sb)->log;
444 logdiff(difft, lsn, log);
445
446 /*
447 * update the block state a dmap at a time.
448 */
449 mp = NULL;
450 lastlblkno = 0;
451 for (rem = nblocks; rem > 0; rem -= nblks, blkno += nblks) {
452 /* get the buffer for the current dmap. */
453 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
454 if (lblkno != lastlblkno) {
455 if (mp) {
456 write_metapage(mp);
457 }
458
459 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE,
460 0);
461 if (mp == NULL)
462 return -EIO;
Dave Kleikamp7fab4792005-05-02 12:25:02 -0600463 metapage_wait_for_io(mp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 }
465 dp = (struct dmap *) mp->data;
466
467 /* determine the bit number and word within the dmap of
468 * the starting block. also determine how many blocks
469 * are to be updated within this dmap.
470 */
471 dbitno = blkno & (BPERDMAP - 1);
472 word = dbitno >> L2DBWORD;
473 nblks = min(rem, (s64)BPERDMAP - dbitno);
474
475 /* update the bits of the dmap words. the first and last
476 * words may only have a subset of their bits updated. if
477 * this is the case, we'll work against that word (i.e.
Dave Kleikamp63f83c92006-10-02 09:55:27 -0500478 * partial first and/or last) only in a single pass. a
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 * single pass will also be used to update all words that
480 * are to have all their bits updated.
481 */
482 for (rbits = nblks; rbits > 0;
483 rbits -= nbits, dbitno += nbits) {
484 /* determine the bit number within the word and
485 * the number of bits within the word.
486 */
487 wbitno = dbitno & (DBWORD - 1);
488 nbits = min(rbits, DBWORD - wbitno);
489
490 /* check if only part of the word is to be updated. */
491 if (nbits < DBWORD) {
492 /* update (free or allocate) the bits
493 * in this word.
494 */
495 mask =
496 (ONES << (DBWORD - nbits) >> wbitno);
497 if (free)
498 dp->pmap[word] &=
499 cpu_to_le32(~mask);
500 else
501 dp->pmap[word] |=
502 cpu_to_le32(mask);
503
504 word += 1;
505 } else {
506 /* one or more words are to have all
507 * their bits updated. determine how
508 * many words and how many bits.
509 */
510 nwords = rbits >> L2DBWORD;
511 nbits = nwords << L2DBWORD;
512
513 /* update (free or allocate) the bits
514 * in these words.
515 */
516 if (free)
517 memset(&dp->pmap[word], 0,
518 nwords * 4);
519 else
520 memset(&dp->pmap[word], (int) ONES,
521 nwords * 4);
522
523 word += nwords;
524 }
525 }
526
527 /*
528 * update dmap lsn
529 */
530 if (lblkno == lastlblkno)
531 continue;
532
533 lastlblkno = lblkno;
534
Dave Kleikampbe0bf7d2006-03-08 10:59:15 -0600535 LOGSYNC_LOCK(log, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536 if (mp->lsn != 0) {
537 /* inherit older/smaller lsn */
538 logdiff(diffp, mp->lsn, log);
539 if (difft < diffp) {
540 mp->lsn = lsn;
541
542 /* move bp after tblock in logsync list */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 list_move(&mp->synclist, &tblk->synclist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544 }
545
546 /* inherit younger/larger clsn */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547 logdiff(difft, tblk->clsn, log);
548 logdiff(diffp, mp->clsn, log);
549 if (difft > diffp)
550 mp->clsn = tblk->clsn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 } else {
552 mp->log = log;
553 mp->lsn = lsn;
554
555 /* insert bp after tblock in logsync list */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 log->count++;
557 list_add(&mp->synclist, &tblk->synclist);
558
559 mp->clsn = tblk->clsn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 }
Dave Kleikampbe0bf7d2006-03-08 10:59:15 -0600561 LOGSYNC_UNLOCK(log, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 }
563
564 /* write the last buffer. */
565 if (mp) {
566 write_metapage(mp);
567 }
568
569 return (0);
570}
571
572
573/*
574 * NAME: dbNextAG()
575 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500576 * FUNCTION: find the preferred allocation group for new allocations.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 *
578 * Within the allocation groups, we maintain a preferred
579 * allocation group which consists of a group with at least
580 * average free space. It is the preferred group that we target
581 * new inode allocation towards. The tie-in between inode
582 * allocation and block allocation occurs as we allocate the
583 * first (data) block of an inode and specify the inode (block)
584 * as the allocation hint for this block.
585 *
586 * We try to avoid having more than one open file growing in
587 * an allocation group, as this will lead to fragmentation.
588 * This differs from the old OS/2 method of trying to keep
589 * empty ags around for large allocations.
590 *
591 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500592 * ipbmap - pointer to in-core inode for the block map.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 *
594 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500595 * the preferred allocation group number.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 */
597int dbNextAG(struct inode *ipbmap)
598{
599 s64 avgfree;
600 int agpref;
601 s64 hwm = 0;
602 int i;
603 int next_best = -1;
604 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
605
606 BMAP_LOCK(bmp);
607
608 /* determine the average number of free blocks within the ags. */
609 avgfree = (u32)bmp->db_nfree / bmp->db_numag;
610
611 /*
612 * if the current preferred ag does not have an active allocator
613 * and has at least average freespace, return it
614 */
615 agpref = bmp->db_agpref;
616 if ((atomic_read(&bmp->db_active[agpref]) == 0) &&
617 (bmp->db_agfree[agpref] >= avgfree))
618 goto unlock;
619
620 /* From the last preferred ag, find the next one with at least
621 * average free space.
622 */
623 for (i = 0 ; i < bmp->db_numag; i++, agpref++) {
624 if (agpref == bmp->db_numag)
625 agpref = 0;
626
627 if (atomic_read(&bmp->db_active[agpref]))
628 /* open file is currently growing in this ag */
629 continue;
630 if (bmp->db_agfree[agpref] >= avgfree) {
631 /* Return this one */
632 bmp->db_agpref = agpref;
633 goto unlock;
634 } else if (bmp->db_agfree[agpref] > hwm) {
635 /* Less than avg. freespace, but best so far */
636 hwm = bmp->db_agfree[agpref];
637 next_best = agpref;
638 }
639 }
640
641 /*
642 * If no inactive ag was found with average freespace, use the
643 * next best
644 */
645 if (next_best != -1)
646 bmp->db_agpref = next_best;
647 /* else leave db_agpref unchanged */
648unlock:
649 BMAP_UNLOCK(bmp);
650
651 /* return the preferred group.
652 */
653 return (bmp->db_agpref);
654}
655
656/*
657 * NAME: dbAlloc()
658 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500659 * FUNCTION: attempt to allocate a specified number of contiguous free
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 * blocks from the working allocation block map.
661 *
662 * the block allocation policy uses hints and a multi-step
663 * approach.
664 *
Dave Kleikamp63f83c92006-10-02 09:55:27 -0500665 * for allocation requests smaller than the number of blocks
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 * per dmap, we first try to allocate the new blocks
667 * immediately following the hint. if these blocks are not
668 * available, we try to allocate blocks near the hint. if
Dave Kleikamp63f83c92006-10-02 09:55:27 -0500669 * no blocks near the hint are available, we next try to
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670 * allocate within the same dmap as contains the hint.
671 *
672 * if no blocks are available in the dmap or the allocation
673 * request is larger than the dmap size, we try to allocate
674 * within the same allocation group as contains the hint. if
675 * this does not succeed, we finally try to allocate anywhere
676 * within the aggregate.
677 *
678 * we also try to allocate anywhere within the aggregate for
679 * for allocation requests larger than the allocation group
680 * size or requests that specify no hint value.
681 *
682 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500683 * ip - pointer to in-core inode;
684 * hint - allocation hint.
685 * nblocks - number of contiguous blocks in the range.
686 * results - on successful return, set to the starting block number
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687 * of the newly allocated contiguous range.
688 *
689 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500690 * 0 - success
691 * -ENOSPC - insufficient disk resources
692 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693 */
694int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results)
695{
696 int rc, agno;
697 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
698 struct bmap *bmp;
699 struct metapage *mp;
700 s64 lblkno, blkno;
701 struct dmap *dp;
702 int l2nb;
703 s64 mapSize;
704 int writers;
705
706 /* assert that nblocks is valid */
707 assert(nblocks > 0);
708
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 /* get the log2 number of blocks to be allocated.
Dave Kleikamp63f83c92006-10-02 09:55:27 -0500710 * if the number of blocks is not a log2 multiple,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711 * it will be rounded up to the next log2 multiple.
712 */
713 l2nb = BLKSTOL2(nblocks);
714
715 bmp = JFS_SBI(ip->i_sb)->bmap;
716
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717 mapSize = bmp->db_mapsize;
718
719 /* the hint should be within the map */
720 if (hint >= mapSize) {
721 jfs_error(ip->i_sb, "dbAlloc: the hint is outside the map");
722 return -EIO;
723 }
724
725 /* if the number of blocks to be allocated is greater than the
726 * allocation group size, try to allocate anywhere.
727 */
728 if (l2nb > bmp->db_agl2size) {
Dave Kleikamp82d5b9a2007-01-09 14:14:48 -0600729 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730
731 rc = dbAllocAny(bmp, nblocks, l2nb, results);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732
733 goto write_unlock;
734 }
735
736 /*
737 * If no hint, let dbNextAG recommend an allocation group
738 */
739 if (hint == 0)
740 goto pref_ag;
741
742 /* we would like to allocate close to the hint. adjust the
743 * hint to the block following the hint since the allocators
744 * will start looking for free space starting at this point.
745 */
746 blkno = hint + 1;
747
748 if (blkno >= bmp->db_mapsize)
749 goto pref_ag;
750
751 agno = blkno >> bmp->db_agl2size;
752
753 /* check if blkno crosses over into a new allocation group.
754 * if so, check if we should allow allocations within this
755 * allocation group.
756 */
757 if ((blkno & (bmp->db_agsize - 1)) == 0)
758 /* check if the AG is currenly being written to.
759 * if so, call dbNextAG() to find a non-busy
760 * AG with sufficient free space.
761 */
762 if (atomic_read(&bmp->db_active[agno]))
763 goto pref_ag;
764
765 /* check if the allocation request size can be satisfied from a
766 * single dmap. if so, try to allocate from the dmap containing
767 * the hint using a tiered strategy.
768 */
769 if (nblocks <= BPERDMAP) {
Dave Kleikamp82d5b9a2007-01-09 14:14:48 -0600770 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771
772 /* get the buffer for the dmap containing the hint.
773 */
774 rc = -EIO;
775 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
776 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
777 if (mp == NULL)
778 goto read_unlock;
779
780 dp = (struct dmap *) mp->data;
781
782 /* first, try to satisfy the allocation request with the
783 * blocks beginning at the hint.
784 */
785 if ((rc = dbAllocNext(bmp, dp, blkno, (int) nblocks))
786 != -ENOSPC) {
787 if (rc == 0) {
788 *results = blkno;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789 mark_metapage_dirty(mp);
790 }
791
792 release_metapage(mp);
793 goto read_unlock;
794 }
795
796 writers = atomic_read(&bmp->db_active[agno]);
797 if ((writers > 1) ||
798 ((writers == 1) && (JFS_IP(ip)->active_ag != agno))) {
799 /*
800 * Someone else is writing in this allocation
801 * group. To avoid fragmenting, try another ag
802 */
803 release_metapage(mp);
804 IREAD_UNLOCK(ipbmap);
805 goto pref_ag;
806 }
807
808 /* next, try to satisfy the allocation request with blocks
809 * near the hint.
810 */
811 if ((rc =
812 dbAllocNear(bmp, dp, blkno, (int) nblocks, l2nb, results))
813 != -ENOSPC) {
Dave Kleikampb38a3ab2005-06-27 15:35:37 -0500814 if (rc == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 mark_metapage_dirty(mp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816
817 release_metapage(mp);
818 goto read_unlock;
819 }
820
821 /* try to satisfy the allocation request with blocks within
822 * the same dmap as the hint.
823 */
824 if ((rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results))
825 != -ENOSPC) {
Dave Kleikampb38a3ab2005-06-27 15:35:37 -0500826 if (rc == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827 mark_metapage_dirty(mp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828
829 release_metapage(mp);
830 goto read_unlock;
831 }
832
833 release_metapage(mp);
834 IREAD_UNLOCK(ipbmap);
835 }
836
837 /* try to satisfy the allocation request with blocks within
838 * the same allocation group as the hint.
839 */
Dave Kleikamp82d5b9a2007-01-09 14:14:48 -0600840 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
Dave Kleikampb38a3ab2005-06-27 15:35:37 -0500841 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) != -ENOSPC)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 goto write_unlock;
Dave Kleikampb38a3ab2005-06-27 15:35:37 -0500843
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 IWRITE_UNLOCK(ipbmap);
845
846
847 pref_ag:
848 /*
849 * Let dbNextAG recommend a preferred allocation group
850 */
851 agno = dbNextAG(ipbmap);
Dave Kleikamp82d5b9a2007-01-09 14:14:48 -0600852 IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853
854 /* Try to allocate within this allocation group. if that fails, try to
855 * allocate anywhere in the map.
856 */
857 if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) == -ENOSPC)
858 rc = dbAllocAny(bmp, nblocks, l2nb, results);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859
860 write_unlock:
861 IWRITE_UNLOCK(ipbmap);
862
863 return (rc);
864
865 read_unlock:
866 IREAD_UNLOCK(ipbmap);
867
868 return (rc);
869}
870
871#ifdef _NOTYET
872/*
873 * NAME: dbAllocExact()
874 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500875 * FUNCTION: try to allocate the requested extent;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 *
877 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500878 * ip - pointer to in-core inode;
879 * blkno - extent address;
880 * nblocks - extent length;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881 *
882 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500883 * 0 - success
884 * -ENOSPC - insufficient disk resources
885 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886 */
887int dbAllocExact(struct inode *ip, s64 blkno, int nblocks)
888{
889 int rc;
890 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
891 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
892 struct dmap *dp;
893 s64 lblkno;
894 struct metapage *mp;
895
Dave Kleikamp82d5b9a2007-01-09 14:14:48 -0600896 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897
898 /*
899 * validate extent request:
900 *
901 * note: defragfs policy:
Dave Kleikamp63f83c92006-10-02 09:55:27 -0500902 * max 64 blocks will be moved.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903 * allocation request size must be satisfied from a single dmap.
904 */
905 if (nblocks <= 0 || nblocks > BPERDMAP || blkno >= bmp->db_mapsize) {
906 IREAD_UNLOCK(ipbmap);
907 return -EINVAL;
908 }
909
910 if (nblocks > ((s64) 1 << bmp->db_maxfreebud)) {
911 /* the free space is no longer available */
912 IREAD_UNLOCK(ipbmap);
913 return -ENOSPC;
914 }
915
916 /* read in the dmap covering the extent */
917 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
918 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
919 if (mp == NULL) {
920 IREAD_UNLOCK(ipbmap);
921 return -EIO;
922 }
923 dp = (struct dmap *) mp->data;
924
925 /* try to allocate the requested extent */
926 rc = dbAllocNext(bmp, dp, blkno, nblocks);
927
928 IREAD_UNLOCK(ipbmap);
929
Dave Kleikampb38a3ab2005-06-27 15:35:37 -0500930 if (rc == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931 mark_metapage_dirty(mp);
Dave Kleikampb38a3ab2005-06-27 15:35:37 -0500932
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 release_metapage(mp);
934
935 return (rc);
936}
937#endif /* _NOTYET */
938
939/*
940 * NAME: dbReAlloc()
941 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500942 * FUNCTION: attempt to extend a current allocation by a specified
Linus Torvalds1da177e2005-04-16 15:20:36 -0700943 * number of blocks.
944 *
945 * this routine attempts to satisfy the allocation request
946 * by first trying to extend the existing allocation in
947 * place by allocating the additional blocks as the blocks
948 * immediately following the current allocation. if these
949 * blocks are not available, this routine will attempt to
950 * allocate a new set of contiguous blocks large enough
951 * to cover the existing allocation plus the additional
952 * number of blocks required.
953 *
954 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500955 * ip - pointer to in-core inode requiring allocation.
956 * blkno - starting block of the current allocation.
957 * nblocks - number of contiguous blocks within the current
Linus Torvalds1da177e2005-04-16 15:20:36 -0700958 * allocation.
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500959 * addnblocks - number of blocks to add to the allocation.
960 * results - on successful return, set to the starting block number
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961 * of the existing allocation if the existing allocation
962 * was extended in place or to a newly allocated contiguous
963 * range if the existing allocation could not be extended
964 * in place.
965 *
966 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -0500967 * 0 - success
968 * -ENOSPC - insufficient disk resources
969 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970 */
971int
972dbReAlloc(struct inode *ip,
973 s64 blkno, s64 nblocks, s64 addnblocks, s64 * results)
974{
975 int rc;
976
977 /* try to extend the allocation in place.
978 */
979 if ((rc = dbExtend(ip, blkno, nblocks, addnblocks)) == 0) {
980 *results = blkno;
981 return (0);
982 } else {
983 if (rc != -ENOSPC)
984 return (rc);
985 }
986
987 /* could not extend the allocation in place, so allocate a
988 * new set of blocks for the entire request (i.e. try to get
989 * a range of contiguous blocks large enough to cover the
990 * existing allocation plus the additional blocks.)
991 */
992 return (dbAlloc
993 (ip, blkno + nblocks - 1, addnblocks + nblocks, results));
994}
995
996
997/*
998 * NAME: dbExtend()
999 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001000 * FUNCTION: attempt to extend a current allocation by a specified
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001 * number of blocks.
1002 *
1003 * this routine attempts to satisfy the allocation request
1004 * by first trying to extend the existing allocation in
1005 * place by allocating the additional blocks as the blocks
1006 * immediately following the current allocation.
1007 *
1008 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001009 * ip - pointer to in-core inode requiring allocation.
1010 * blkno - starting block of the current allocation.
1011 * nblocks - number of contiguous blocks within the current
Linus Torvalds1da177e2005-04-16 15:20:36 -07001012 * allocation.
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001013 * addnblocks - number of blocks to add to the allocation.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 *
1015 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001016 * 0 - success
1017 * -ENOSPC - insufficient disk resources
1018 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019 */
1020static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks)
1021{
1022 struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
1023 s64 lblkno, lastblkno, extblkno;
1024 uint rel_block;
1025 struct metapage *mp;
1026 struct dmap *dp;
1027 int rc;
1028 struct inode *ipbmap = sbi->ipbmap;
1029 struct bmap *bmp;
1030
1031 /*
1032 * We don't want a non-aligned extent to cross a page boundary
1033 */
1034 if (((rel_block = blkno & (sbi->nbperpage - 1))) &&
1035 (rel_block + nblocks + addnblocks > sbi->nbperpage))
1036 return -ENOSPC;
1037
1038 /* get the last block of the current allocation */
1039 lastblkno = blkno + nblocks - 1;
1040
1041 /* determine the block number of the block following
1042 * the existing allocation.
1043 */
1044 extblkno = lastblkno + 1;
1045
Dave Kleikamp82d5b9a2007-01-09 14:14:48 -06001046 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001047
1048 /* better be within the file system */
1049 bmp = sbi->bmap;
1050 if (lastblkno < 0 || lastblkno >= bmp->db_mapsize) {
1051 IREAD_UNLOCK(ipbmap);
1052 jfs_error(ip->i_sb,
1053 "dbExtend: the block is outside the filesystem");
1054 return -EIO;
1055 }
1056
1057 /* we'll attempt to extend the current allocation in place by
1058 * allocating the additional blocks as the blocks immediately
1059 * following the current allocation. we only try to extend the
1060 * current allocation in place if the number of additional blocks
1061 * can fit into a dmap, the last block of the current allocation
1062 * is not the last block of the file system, and the start of the
1063 * inplace extension is not on an allocation group boundary.
1064 */
1065 if (addnblocks > BPERDMAP || extblkno >= bmp->db_mapsize ||
1066 (extblkno & (bmp->db_agsize - 1)) == 0) {
1067 IREAD_UNLOCK(ipbmap);
1068 return -ENOSPC;
1069 }
1070
1071 /* get the buffer for the dmap containing the first block
1072 * of the extension.
1073 */
1074 lblkno = BLKTODMAP(extblkno, bmp->db_l2nbperpage);
1075 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
1076 if (mp == NULL) {
1077 IREAD_UNLOCK(ipbmap);
1078 return -EIO;
1079 }
1080
Linus Torvalds1da177e2005-04-16 15:20:36 -07001081 dp = (struct dmap *) mp->data;
1082
1083 /* try to allocate the blocks immediately following the
1084 * current allocation.
1085 */
1086 rc = dbAllocNext(bmp, dp, extblkno, (int) addnblocks);
1087
1088 IREAD_UNLOCK(ipbmap);
1089
1090 /* were we successful ? */
Dave Kleikampb38a3ab2005-06-27 15:35:37 -05001091 if (rc == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092 write_metapage(mp);
Dave Kleikampb38a3ab2005-06-27 15:35:37 -05001093 else
Linus Torvalds1da177e2005-04-16 15:20:36 -07001094 /* we were not successful */
1095 release_metapage(mp);
1096
1097
1098 return (rc);
1099}
1100
1101
1102/*
1103 * NAME: dbAllocNext()
1104 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001105 * FUNCTION: attempt to allocate the blocks of the specified block
Linus Torvalds1da177e2005-04-16 15:20:36 -07001106 * range within a dmap.
1107 *
1108 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001109 * bmp - pointer to bmap descriptor
1110 * dp - pointer to dmap.
1111 * blkno - starting block number of the range.
1112 * nblocks - number of contiguous free blocks of the range.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113 *
1114 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001115 * 0 - success
1116 * -ENOSPC - insufficient disk resources
1117 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118 *
1119 * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1120 */
1121static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
1122 int nblocks)
1123{
1124 int dbitno, word, rembits, nb, nwords, wbitno, nw;
1125 int l2size;
1126 s8 *leaf;
1127 u32 mask;
1128
1129 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1130 jfs_error(bmp->db_ipbmap->i_sb,
1131 "dbAllocNext: Corrupt dmap page");
1132 return -EIO;
1133 }
1134
1135 /* pick up a pointer to the leaves of the dmap tree.
1136 */
1137 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1138
1139 /* determine the bit number and word within the dmap of the
1140 * starting block.
1141 */
1142 dbitno = blkno & (BPERDMAP - 1);
1143 word = dbitno >> L2DBWORD;
1144
1145 /* check if the specified block range is contained within
1146 * this dmap.
1147 */
1148 if (dbitno + nblocks > BPERDMAP)
1149 return -ENOSPC;
1150
1151 /* check if the starting leaf indicates that anything
1152 * is free.
1153 */
1154 if (leaf[word] == NOFREE)
1155 return -ENOSPC;
1156
1157 /* check the dmaps words corresponding to block range to see
1158 * if the block range is free. not all bits of the first and
1159 * last words may be contained within the block range. if this
1160 * is the case, we'll work against those words (i.e. partial first
1161 * and/or last) on an individual basis (a single pass) and examine
1162 * the actual bits to determine if they are free. a single pass
1163 * will be used for all dmap words fully contained within the
1164 * specified range. within this pass, the leaves of the dmap
1165 * tree will be examined to determine if the blocks are free. a
1166 * single leaf may describe the free space of multiple dmap
1167 * words, so we may visit only a subset of the actual leaves
1168 * corresponding to the dmap words of the block range.
1169 */
1170 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
1171 /* determine the bit number within the word and
1172 * the number of bits within the word.
1173 */
1174 wbitno = dbitno & (DBWORD - 1);
1175 nb = min(rembits, DBWORD - wbitno);
1176
1177 /* check if only part of the word is to be examined.
1178 */
1179 if (nb < DBWORD) {
1180 /* check if the bits are free.
1181 */
1182 mask = (ONES << (DBWORD - nb) >> wbitno);
1183 if ((mask & ~le32_to_cpu(dp->wmap[word])) != mask)
1184 return -ENOSPC;
1185
1186 word += 1;
1187 } else {
1188 /* one or more dmap words are fully contained
1189 * within the block range. determine how many
1190 * words and how many bits.
1191 */
1192 nwords = rembits >> L2DBWORD;
1193 nb = nwords << L2DBWORD;
1194
1195 /* now examine the appropriate leaves to determine
1196 * if the blocks are free.
1197 */
1198 while (nwords > 0) {
1199 /* does the leaf describe any free space ?
1200 */
1201 if (leaf[word] < BUDMIN)
1202 return -ENOSPC;
1203
1204 /* determine the l2 number of bits provided
1205 * by this leaf.
1206 */
1207 l2size =
1208 min((int)leaf[word], NLSTOL2BSZ(nwords));
1209
1210 /* determine how many words were handled.
1211 */
1212 nw = BUDSIZE(l2size, BUDMIN);
1213
1214 nwords -= nw;
1215 word += nw;
1216 }
1217 }
1218 }
1219
1220 /* allocate the blocks.
1221 */
1222 return (dbAllocDmap(bmp, dp, blkno, nblocks));
1223}
1224
1225
1226/*
1227 * NAME: dbAllocNear()
1228 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001229 * FUNCTION: attempt to allocate a number of contiguous free blocks near
Linus Torvalds1da177e2005-04-16 15:20:36 -07001230 * a specified block (hint) within a dmap.
1231 *
1232 * starting with the dmap leaf that covers the hint, we'll
1233 * check the next four contiguous leaves for sufficient free
1234 * space. if sufficient free space is found, we'll allocate
1235 * the desired free space.
1236 *
1237 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001238 * bmp - pointer to bmap descriptor
1239 * dp - pointer to dmap.
1240 * blkno - block number to allocate near.
1241 * nblocks - actual number of contiguous free blocks desired.
1242 * l2nb - log2 number of contiguous free blocks desired.
1243 * results - on successful return, set to the starting block number
Linus Torvalds1da177e2005-04-16 15:20:36 -07001244 * of the newly allocated range.
1245 *
1246 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001247 * 0 - success
1248 * -ENOSPC - insufficient disk resources
1249 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -07001250 *
1251 * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1252 */
1253static int
1254dbAllocNear(struct bmap * bmp,
1255 struct dmap * dp, s64 blkno, int nblocks, int l2nb, s64 * results)
1256{
1257 int word, lword, rc;
1258 s8 *leaf;
1259
1260 if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1261 jfs_error(bmp->db_ipbmap->i_sb,
1262 "dbAllocNear: Corrupt dmap page");
1263 return -EIO;
1264 }
1265
1266 leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1267
1268 /* determine the word within the dmap that holds the hint
1269 * (i.e. blkno). also, determine the last word in the dmap
1270 * that we'll include in our examination.
1271 */
1272 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
1273 lword = min(word + 4, LPERDMAP);
1274
1275 /* examine the leaves for sufficient free space.
1276 */
1277 for (; word < lword; word++) {
1278 /* does the leaf describe sufficient free space ?
1279 */
1280 if (leaf[word] < l2nb)
1281 continue;
1282
1283 /* determine the block number within the file system
1284 * of the first block described by this dmap word.
1285 */
1286 blkno = le64_to_cpu(dp->start) + (word << L2DBWORD);
1287
1288 /* if not all bits of the dmap word are free, get the
1289 * starting bit number within the dmap word of the required
1290 * string of free bits and adjust the block number with the
1291 * value.
1292 */
1293 if (leaf[word] < BUDMIN)
1294 blkno +=
1295 dbFindBits(le32_to_cpu(dp->wmap[word]), l2nb);
1296
1297 /* allocate the blocks.
1298 */
1299 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1300 *results = blkno;
1301
1302 return (rc);
1303 }
1304
1305 return -ENOSPC;
1306}
1307
1308
1309/*
1310 * NAME: dbAllocAG()
1311 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001312 * FUNCTION: attempt to allocate the specified number of contiguous
Linus Torvalds1da177e2005-04-16 15:20:36 -07001313 * free blocks within the specified allocation group.
1314 *
1315 * unless the allocation group size is equal to the number
1316 * of blocks per dmap, the dmap control pages will be used to
1317 * find the required free space, if available. we start the
1318 * search at the highest dmap control page level which
1319 * distinctly describes the allocation group's free space
1320 * (i.e. the highest level at which the allocation group's
1321 * free space is not mixed in with that of any other group).
1322 * in addition, we start the search within this level at a
1323 * height of the dmapctl dmtree at which the nodes distinctly
1324 * describe the allocation group's free space. at this height,
1325 * the allocation group's free space may be represented by 1
1326 * or two sub-trees, depending on the allocation group size.
1327 * we search the top nodes of these subtrees left to right for
1328 * sufficient free space. if sufficient free space is found,
Dave Kleikamp63f83c92006-10-02 09:55:27 -05001329 * the subtree is searched to find the leftmost leaf that
Linus Torvalds1da177e2005-04-16 15:20:36 -07001330 * has free space. once we have made it to the leaf, we
1331 * move the search to the next lower level dmap control page
1332 * corresponding to this leaf. we continue down the dmap control
1333 * pages until we find the dmap that contains or starts the
1334 * sufficient free space and we allocate at this dmap.
1335 *
1336 * if the allocation group size is equal to the dmap size,
1337 * we'll start at the dmap corresponding to the allocation
1338 * group and attempt the allocation at this level.
1339 *
1340 * the dmap control page search is also not performed if the
1341 * allocation group is completely free and we go to the first
1342 * dmap of the allocation group to do the allocation. this is
1343 * done because the allocation group may be part (not the first
1344 * part) of a larger binary buddy system, causing the dmap
1345 * control pages to indicate no free space (NOFREE) within
1346 * the allocation group.
1347 *
1348 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001349 * bmp - pointer to bmap descriptor
Linus Torvalds1da177e2005-04-16 15:20:36 -07001350 * agno - allocation group number.
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001351 * nblocks - actual number of contiguous free blocks desired.
1352 * l2nb - log2 number of contiguous free blocks desired.
1353 * results - on successful return, set to the starting block number
Linus Torvalds1da177e2005-04-16 15:20:36 -07001354 * of the newly allocated range.
1355 *
1356 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001357 * 0 - success
1358 * -ENOSPC - insufficient disk resources
1359 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -07001360 *
1361 * note: IWRITE_LOCK(ipmap) held on entry/exit;
1362 */
1363static int
1364dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, s64 * results)
1365{
1366 struct metapage *mp;
1367 struct dmapctl *dcp;
1368 int rc, ti, i, k, m, n, agperlev;
1369 s64 blkno, lblkno;
1370 int budmin;
1371
1372 /* allocation request should not be for more than the
1373 * allocation group size.
1374 */
1375 if (l2nb > bmp->db_agl2size) {
1376 jfs_error(bmp->db_ipbmap->i_sb,
1377 "dbAllocAG: allocation request is larger than the "
1378 "allocation group size");
1379 return -EIO;
1380 }
1381
1382 /* determine the starting block number of the allocation
1383 * group.
1384 */
1385 blkno = (s64) agno << bmp->db_agl2size;
1386
1387 /* check if the allocation group size is the minimum allocation
1388 * group size or if the allocation group is completely free. if
1389 * the allocation group size is the minimum size of BPERDMAP (i.e.
1390 * 1 dmap), there is no need to search the dmap control page (below)
1391 * that fully describes the allocation group since the allocation
1392 * group is already fully described by a dmap. in this case, we
1393 * just call dbAllocCtl() to search the dmap tree and allocate the
Dave Kleikamp63f83c92006-10-02 09:55:27 -05001394 * required space if available.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001395 *
1396 * if the allocation group is completely free, dbAllocCtl() is
1397 * also called to allocate the required space. this is done for
1398 * two reasons. first, it makes no sense searching the dmap control
1399 * pages for free space when we know that free space exists. second,
1400 * the dmap control pages may indicate that the allocation group
1401 * has no free space if the allocation group is part (not the first
1402 * part) of a larger binary buddy system.
1403 */
1404 if (bmp->db_agsize == BPERDMAP
1405 || bmp->db_agfree[agno] == bmp->db_agsize) {
1406 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1407 if ((rc == -ENOSPC) &&
1408 (bmp->db_agfree[agno] == bmp->db_agsize)) {
1409 printk(KERN_ERR "blkno = %Lx, blocks = %Lx\n",
1410 (unsigned long long) blkno,
1411 (unsigned long long) nblocks);
1412 jfs_error(bmp->db_ipbmap->i_sb,
1413 "dbAllocAG: dbAllocCtl failed in free AG");
1414 }
1415 return (rc);
1416 }
1417
1418 /* the buffer for the dmap control page that fully describes the
1419 * allocation group.
1420 */
1421 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, bmp->db_aglevel);
1422 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1423 if (mp == NULL)
1424 return -EIO;
1425 dcp = (struct dmapctl *) mp->data;
1426 budmin = dcp->budmin;
1427
1428 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1429 jfs_error(bmp->db_ipbmap->i_sb,
1430 "dbAllocAG: Corrupt dmapctl page");
1431 release_metapage(mp);
1432 return -EIO;
1433 }
1434
1435 /* search the subtree(s) of the dmap control page that describes
1436 * the allocation group, looking for sufficient free space. to begin,
1437 * determine how many allocation groups are represented in a dmap
1438 * control page at the control page level (i.e. L0, L1, L2) that
1439 * fully describes an allocation group. next, determine the starting
1440 * tree index of this allocation group within the control page.
1441 */
1442 agperlev =
1443 (1 << (L2LPERCTL - (bmp->db_agheigth << 1))) / bmp->db_agwidth;
1444 ti = bmp->db_agstart + bmp->db_agwidth * (agno & (agperlev - 1));
1445
Dave Kleikamp63f83c92006-10-02 09:55:27 -05001446 /* dmap control page trees fan-out by 4 and a single allocation
Linus Torvalds1da177e2005-04-16 15:20:36 -07001447 * group may be described by 1 or 2 subtrees within the ag level
1448 * dmap control page, depending upon the ag size. examine the ag's
1449 * subtrees for sufficient free space, starting with the leftmost
1450 * subtree.
1451 */
1452 for (i = 0; i < bmp->db_agwidth; i++, ti++) {
1453 /* is there sufficient free space ?
1454 */
1455 if (l2nb > dcp->stree[ti])
1456 continue;
1457
1458 /* sufficient free space found in a subtree. now search down
1459 * the subtree to find the leftmost leaf that describes this
1460 * free space.
1461 */
1462 for (k = bmp->db_agheigth; k > 0; k--) {
1463 for (n = 0, m = (ti << 2) + 1; n < 4; n++) {
1464 if (l2nb <= dcp->stree[m + n]) {
1465 ti = m + n;
1466 break;
1467 }
1468 }
1469 if (n == 4) {
1470 jfs_error(bmp->db_ipbmap->i_sb,
1471 "dbAllocAG: failed descending stree");
1472 release_metapage(mp);
1473 return -EIO;
1474 }
1475 }
1476
1477 /* determine the block number within the file system
1478 * that corresponds to this leaf.
1479 */
1480 if (bmp->db_aglevel == 2)
1481 blkno = 0;
1482 else if (bmp->db_aglevel == 1)
1483 blkno &= ~(MAXL1SIZE - 1);
1484 else /* bmp->db_aglevel == 0 */
1485 blkno &= ~(MAXL0SIZE - 1);
1486
1487 blkno +=
1488 ((s64) (ti - le32_to_cpu(dcp->leafidx))) << budmin;
1489
1490 /* release the buffer in preparation for going down
1491 * the next level of dmap control pages.
1492 */
1493 release_metapage(mp);
1494
1495 /* check if we need to continue to search down the lower
1496 * level dmap control pages. we need to if the number of
1497 * blocks required is less than maximum number of blocks
1498 * described at the next lower level.
1499 */
1500 if (l2nb < budmin) {
1501
1502 /* search the lower level dmap control pages to get
Michael Opdenacker59c51592007-05-09 08:57:56 +02001503 * the starting block number of the dmap that
Linus Torvalds1da177e2005-04-16 15:20:36 -07001504 * contains or starts off the free space.
1505 */
1506 if ((rc =
1507 dbFindCtl(bmp, l2nb, bmp->db_aglevel - 1,
1508 &blkno))) {
1509 if (rc == -ENOSPC) {
1510 jfs_error(bmp->db_ipbmap->i_sb,
1511 "dbAllocAG: control page "
1512 "inconsistent");
1513 return -EIO;
1514 }
1515 return (rc);
1516 }
1517 }
1518
1519 /* allocate the blocks.
1520 */
1521 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1522 if (rc == -ENOSPC) {
1523 jfs_error(bmp->db_ipbmap->i_sb,
1524 "dbAllocAG: unable to allocate blocks");
1525 rc = -EIO;
1526 }
1527 return (rc);
1528 }
1529
1530 /* no space in the allocation group. release the buffer and
1531 * return -ENOSPC.
1532 */
1533 release_metapage(mp);
1534
1535 return -ENOSPC;
1536}
1537
1538
1539/*
1540 * NAME: dbAllocAny()
1541 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001542 * FUNCTION: attempt to allocate the specified number of contiguous
Linus Torvalds1da177e2005-04-16 15:20:36 -07001543 * free blocks anywhere in the file system.
1544 *
1545 * dbAllocAny() attempts to find the sufficient free space by
1546 * searching down the dmap control pages, starting with the
1547 * highest level (i.e. L0, L1, L2) control page. if free space
1548 * large enough to satisfy the desired free space is found, the
1549 * desired free space is allocated.
1550 *
1551 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001552 * bmp - pointer to bmap descriptor
1553 * nblocks - actual number of contiguous free blocks desired.
1554 * l2nb - log2 number of contiguous free blocks desired.
1555 * results - on successful return, set to the starting block number
Linus Torvalds1da177e2005-04-16 15:20:36 -07001556 * of the newly allocated range.
1557 *
1558 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001559 * 0 - success
1560 * -ENOSPC - insufficient disk resources
1561 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -07001562 *
1563 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1564 */
1565static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results)
1566{
1567 int rc;
1568 s64 blkno = 0;
1569
1570 /* starting with the top level dmap control page, search
1571 * down the dmap control levels for sufficient free space.
1572 * if free space is found, dbFindCtl() returns the starting
1573 * block number of the dmap that contains or starts off the
1574 * range of free space.
1575 */
1576 if ((rc = dbFindCtl(bmp, l2nb, bmp->db_maxlevel, &blkno)))
1577 return (rc);
1578
1579 /* allocate the blocks.
1580 */
1581 rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1582 if (rc == -ENOSPC) {
1583 jfs_error(bmp->db_ipbmap->i_sb,
1584 "dbAllocAny: unable to allocate blocks");
1585 return -EIO;
1586 }
1587 return (rc);
1588}
1589
1590
1591/*
1592 * NAME: dbFindCtl()
1593 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001594 * FUNCTION: starting at a specified dmap control page level and block
Linus Torvalds1da177e2005-04-16 15:20:36 -07001595 * number, search down the dmap control levels for a range of
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001596 * contiguous free blocks large enough to satisfy an allocation
Linus Torvalds1da177e2005-04-16 15:20:36 -07001597 * request for the specified number of free blocks.
1598 *
1599 * if sufficient contiguous free blocks are found, this routine
1600 * returns the starting block number within a dmap page that
1601 * contains or starts a range of contiqious free blocks that
1602 * is sufficient in size.
1603 *
1604 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001605 * bmp - pointer to bmap descriptor
1606 * level - starting dmap control page level.
1607 * l2nb - log2 number of contiguous free blocks desired.
1608 * *blkno - on entry, starting block number for conducting the search.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001609 * on successful return, the first block within a dmap page
1610 * that contains or starts a range of contiguous free blocks.
1611 *
1612 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001613 * 0 - success
1614 * -ENOSPC - insufficient disk resources
1615 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -07001616 *
1617 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1618 */
1619static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno)
1620{
1621 int rc, leafidx, lev;
1622 s64 b, lblkno;
1623 struct dmapctl *dcp;
1624 int budmin;
1625 struct metapage *mp;
1626
1627 /* starting at the specified dmap control page level and block
1628 * number, search down the dmap control levels for the starting
Dave Kleikamp63f83c92006-10-02 09:55:27 -05001629 * block number of a dmap page that contains or starts off
Linus Torvalds1da177e2005-04-16 15:20:36 -07001630 * sufficient free blocks.
1631 */
1632 for (lev = level, b = *blkno; lev >= 0; lev--) {
1633 /* get the buffer of the dmap control page for the block
1634 * number and level (i.e. L0, L1, L2).
1635 */
1636 lblkno = BLKTOCTL(b, bmp->db_l2nbperpage, lev);
1637 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1638 if (mp == NULL)
1639 return -EIO;
1640 dcp = (struct dmapctl *) mp->data;
1641 budmin = dcp->budmin;
1642
1643 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1644 jfs_error(bmp->db_ipbmap->i_sb,
1645 "dbFindCtl: Corrupt dmapctl page");
1646 release_metapage(mp);
1647 return -EIO;
1648 }
1649
1650 /* search the tree within the dmap control page for
1651 * sufficent free space. if sufficient free space is found,
1652 * dbFindLeaf() returns the index of the leaf at which
1653 * free space was found.
1654 */
1655 rc = dbFindLeaf((dmtree_t *) dcp, l2nb, &leafidx);
1656
1657 /* release the buffer.
1658 */
1659 release_metapage(mp);
1660
1661 /* space found ?
1662 */
1663 if (rc) {
1664 if (lev != level) {
1665 jfs_error(bmp->db_ipbmap->i_sb,
1666 "dbFindCtl: dmap inconsistent");
1667 return -EIO;
1668 }
1669 return -ENOSPC;
1670 }
1671
1672 /* adjust the block number to reflect the location within
Dave Kleikamp63f83c92006-10-02 09:55:27 -05001673 * the dmap control page (i.e. the leaf) at which free
Linus Torvalds1da177e2005-04-16 15:20:36 -07001674 * space was found.
1675 */
1676 b += (((s64) leafidx) << budmin);
1677
1678 /* we stop the search at this dmap control page level if
1679 * the number of blocks required is greater than or equal
1680 * to the maximum number of blocks described at the next
1681 * (lower) level.
1682 */
1683 if (l2nb >= budmin)
1684 break;
1685 }
1686
1687 *blkno = b;
1688 return (0);
1689}
1690
1691
1692/*
1693 * NAME: dbAllocCtl()
1694 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001695 * FUNCTION: attempt to allocate a specified number of contiguous
Dave Kleikamp63f83c92006-10-02 09:55:27 -05001696 * blocks starting within a specific dmap.
1697 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001698 * this routine is called by higher level routines that search
1699 * the dmap control pages above the actual dmaps for contiguous
1700 * free space. the result of successful searches by these
Dave Kleikamp63f83c92006-10-02 09:55:27 -05001701 * routines are the starting block numbers within dmaps, with
Linus Torvalds1da177e2005-04-16 15:20:36 -07001702 * the dmaps themselves containing the desired contiguous free
1703 * space or starting a contiguous free space of desired size
1704 * that is made up of the blocks of one or more dmaps. these
1705 * calls should not fail due to insufficent resources.
1706 *
1707 * this routine is called in some cases where it is not known
1708 * whether it will fail due to insufficient resources. more
1709 * specifically, this occurs when allocating from an allocation
1710 * group whose size is equal to the number of blocks per dmap.
1711 * in this case, the dmap control pages are not examined prior
1712 * to calling this routine (to save pathlength) and the call
1713 * might fail.
1714 *
1715 * for a request size that fits within a dmap, this routine relies
1716 * upon the dmap's dmtree to find the requested contiguous free
1717 * space. for request sizes that are larger than a dmap, the
1718 * requested free space will start at the first block of the
1719 * first dmap (i.e. blkno).
1720 *
1721 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001722 * bmp - pointer to bmap descriptor
1723 * nblocks - actual number of contiguous free blocks to allocate.
1724 * l2nb - log2 number of contiguous free blocks to allocate.
1725 * blkno - starting block number of the dmap to start the allocation
Linus Torvalds1da177e2005-04-16 15:20:36 -07001726 * from.
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001727 * results - on successful return, set to the starting block number
Linus Torvalds1da177e2005-04-16 15:20:36 -07001728 * of the newly allocated range.
1729 *
1730 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001731 * 0 - success
1732 * -ENOSPC - insufficient disk resources
1733 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -07001734 *
1735 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1736 */
1737static int
1738dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results)
1739{
1740 int rc, nb;
1741 s64 b, lblkno, n;
1742 struct metapage *mp;
1743 struct dmap *dp;
1744
1745 /* check if the allocation request is confined to a single dmap.
1746 */
1747 if (l2nb <= L2BPERDMAP) {
1748 /* get the buffer for the dmap.
1749 */
1750 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
1751 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1752 if (mp == NULL)
1753 return -EIO;
1754 dp = (struct dmap *) mp->data;
1755
1756 /* try to allocate the blocks.
1757 */
1758 rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results);
1759 if (rc == 0)
1760 mark_metapage_dirty(mp);
1761
1762 release_metapage(mp);
1763
1764 return (rc);
1765 }
1766
1767 /* allocation request involving multiple dmaps. it must start on
1768 * a dmap boundary.
1769 */
1770 assert((blkno & (BPERDMAP - 1)) == 0);
1771
1772 /* allocate the blocks dmap by dmap.
1773 */
1774 for (n = nblocks, b = blkno; n > 0; n -= nb, b += nb) {
1775 /* get the buffer for the dmap.
1776 */
1777 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1778 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1779 if (mp == NULL) {
1780 rc = -EIO;
1781 goto backout;
1782 }
1783 dp = (struct dmap *) mp->data;
1784
1785 /* the dmap better be all free.
1786 */
1787 if (dp->tree.stree[ROOT] != L2BPERDMAP) {
1788 release_metapage(mp);
1789 jfs_error(bmp->db_ipbmap->i_sb,
1790 "dbAllocCtl: the dmap is not all free");
1791 rc = -EIO;
1792 goto backout;
1793 }
1794
1795 /* determine how many blocks to allocate from this dmap.
1796 */
1797 nb = min(n, (s64)BPERDMAP);
1798
1799 /* allocate the blocks from the dmap.
1800 */
1801 if ((rc = dbAllocDmap(bmp, dp, b, nb))) {
1802 release_metapage(mp);
1803 goto backout;
1804 }
1805
1806 /* write the buffer.
1807 */
1808 write_metapage(mp);
1809 }
1810
1811 /* set the results (starting block number) and return.
1812 */
1813 *results = blkno;
1814 return (0);
1815
1816 /* something failed in handling an allocation request involving
1817 * multiple dmaps. we'll try to clean up by backing out any
1818 * allocation that has already happened for this request. if
1819 * we fail in backing out the allocation, we'll mark the file
1820 * system to indicate that blocks have been leaked.
1821 */
1822 backout:
1823
1824 /* try to backout the allocations dmap by dmap.
1825 */
1826 for (n = nblocks - n, b = blkno; n > 0;
1827 n -= BPERDMAP, b += BPERDMAP) {
1828 /* get the buffer for this dmap.
1829 */
1830 lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1831 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1832 if (mp == NULL) {
1833 /* could not back out. mark the file system
1834 * to indicate that we have leaked blocks.
1835 */
1836 jfs_error(bmp->db_ipbmap->i_sb,
1837 "dbAllocCtl: I/O Error: Block Leakage.");
1838 continue;
1839 }
1840 dp = (struct dmap *) mp->data;
1841
1842 /* free the blocks is this dmap.
1843 */
1844 if (dbFreeDmap(bmp, dp, b, BPERDMAP)) {
1845 /* could not back out. mark the file system
1846 * to indicate that we have leaked blocks.
1847 */
1848 release_metapage(mp);
1849 jfs_error(bmp->db_ipbmap->i_sb,
1850 "dbAllocCtl: Block Leakage.");
1851 continue;
1852 }
1853
1854 /* write the buffer.
1855 */
1856 write_metapage(mp);
1857 }
1858
1859 return (rc);
1860}
1861
1862
1863/*
1864 * NAME: dbAllocDmapLev()
1865 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001866 * FUNCTION: attempt to allocate a specified number of contiguous blocks
Linus Torvalds1da177e2005-04-16 15:20:36 -07001867 * from a specified dmap.
Dave Kleikamp63f83c92006-10-02 09:55:27 -05001868 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001869 * this routine checks if the contiguous blocks are available.
1870 * if so, nblocks of blocks are allocated; otherwise, ENOSPC is
1871 * returned.
1872 *
1873 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001874 * mp - pointer to bmap descriptor
1875 * dp - pointer to dmap to attempt to allocate blocks from.
1876 * l2nb - log2 number of contiguous block desired.
1877 * nblocks - actual number of contiguous block desired.
1878 * results - on successful return, set to the starting block number
Linus Torvalds1da177e2005-04-16 15:20:36 -07001879 * of the newly allocated range.
1880 *
1881 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001882 * 0 - success
1883 * -ENOSPC - insufficient disk resources
1884 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -07001885 *
Dave Kleikamp63f83c92006-10-02 09:55:27 -05001886 * serialization: IREAD_LOCK(ipbmap), e.g., from dbAlloc(), or
Linus Torvalds1da177e2005-04-16 15:20:36 -07001887 * IWRITE_LOCK(ipbmap), e.g., dbAllocCtl(), held on entry/exit;
1888 */
1889static int
1890dbAllocDmapLev(struct bmap * bmp,
1891 struct dmap * dp, int nblocks, int l2nb, s64 * results)
1892{
1893 s64 blkno;
1894 int leafidx, rc;
1895
1896 /* can't be more than a dmaps worth of blocks */
1897 assert(l2nb <= L2BPERDMAP);
1898
1899 /* search the tree within the dmap page for sufficient
1900 * free space. if sufficient free space is found, dbFindLeaf()
1901 * returns the index of the leaf at which free space was found.
1902 */
1903 if (dbFindLeaf((dmtree_t *) & dp->tree, l2nb, &leafidx))
1904 return -ENOSPC;
1905
1906 /* determine the block number within the file system corresponding
1907 * to the leaf at which free space was found.
1908 */
1909 blkno = le64_to_cpu(dp->start) + (leafidx << L2DBWORD);
1910
1911 /* if not all bits of the dmap word are free, get the starting
1912 * bit number within the dmap word of the required string of free
1913 * bits and adjust the block number with this value.
1914 */
1915 if (dp->tree.stree[leafidx + LEAFIND] < BUDMIN)
1916 blkno += dbFindBits(le32_to_cpu(dp->wmap[leafidx]), l2nb);
1917
1918 /* allocate the blocks */
1919 if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1920 *results = blkno;
1921
1922 return (rc);
1923}
1924
1925
1926/*
1927 * NAME: dbAllocDmap()
1928 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001929 * FUNCTION: adjust the disk allocation map to reflect the allocation
Linus Torvalds1da177e2005-04-16 15:20:36 -07001930 * of a specified block range within a dmap.
1931 *
1932 * this routine allocates the specified blocks from the dmap
1933 * through a call to dbAllocBits(). if the allocation of the
1934 * block range causes the maximum string of free blocks within
1935 * the dmap to change (i.e. the value of the root of the dmap's
1936 * dmtree), this routine will cause this change to be reflected
1937 * up through the appropriate levels of the dmap control pages
1938 * by a call to dbAdjCtl() for the L0 dmap control page that
1939 * covers this dmap.
1940 *
1941 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001942 * bmp - pointer to bmap descriptor
1943 * dp - pointer to dmap to allocate the block range from.
1944 * blkno - starting block number of the block to be allocated.
1945 * nblocks - number of blocks to be allocated.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001946 *
1947 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001948 * 0 - success
1949 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -07001950 *
1951 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
1952 */
1953static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
1954 int nblocks)
1955{
1956 s8 oldroot;
1957 int rc;
1958
1959 /* save the current value of the root (i.e. maximum free string)
1960 * of the dmap tree.
1961 */
1962 oldroot = dp->tree.stree[ROOT];
1963
1964 /* allocate the specified (blocks) bits */
1965 dbAllocBits(bmp, dp, blkno, nblocks);
1966
1967 /* if the root has not changed, done. */
1968 if (dp->tree.stree[ROOT] == oldroot)
1969 return (0);
1970
1971 /* root changed. bubble the change up to the dmap control pages.
1972 * if the adjustment of the upper level control pages fails,
1973 * backout the bit allocation (thus making everything consistent).
1974 */
1975 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 1, 0)))
1976 dbFreeBits(bmp, dp, blkno, nblocks);
1977
1978 return (rc);
1979}
1980
1981
1982/*
1983 * NAME: dbFreeDmap()
1984 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001985 * FUNCTION: adjust the disk allocation map to reflect the allocation
Linus Torvalds1da177e2005-04-16 15:20:36 -07001986 * of a specified block range within a dmap.
1987 *
1988 * this routine frees the specified blocks from the dmap through
1989 * a call to dbFreeBits(). if the deallocation of the block range
1990 * causes the maximum string of free blocks within the dmap to
1991 * change (i.e. the value of the root of the dmap's dmtree), this
1992 * routine will cause this change to be reflected up through the
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001993 * appropriate levels of the dmap control pages by a call to
Linus Torvalds1da177e2005-04-16 15:20:36 -07001994 * dbAdjCtl() for the L0 dmap control page that covers this dmap.
1995 *
1996 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05001997 * bmp - pointer to bmap descriptor
1998 * dp - pointer to dmap to free the block range from.
1999 * blkno - starting block number of the block to be freed.
2000 * nblocks - number of blocks to be freed.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002001 *
2002 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002003 * 0 - success
2004 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -07002005 *
2006 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2007 */
2008static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
2009 int nblocks)
2010{
2011 s8 oldroot;
Dave Kleikamp56d12542005-07-15 09:43:36 -05002012 int rc = 0, word;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002013
2014 /* save the current value of the root (i.e. maximum free string)
2015 * of the dmap tree.
2016 */
2017 oldroot = dp->tree.stree[ROOT];
2018
2019 /* free the specified (blocks) bits */
Dave Kleikamp56d12542005-07-15 09:43:36 -05002020 rc = dbFreeBits(bmp, dp, blkno, nblocks);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002021
Dave Kleikamp56d12542005-07-15 09:43:36 -05002022 /* if error or the root has not changed, done. */
2023 if (rc || (dp->tree.stree[ROOT] == oldroot))
2024 return (rc);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002025
2026 /* root changed. bubble the change up to the dmap control pages.
2027 * if the adjustment of the upper level control pages fails,
Dave Kleikamp63f83c92006-10-02 09:55:27 -05002028 * backout the deallocation.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002029 */
2030 if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 0, 0))) {
2031 word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
2032
2033 /* as part of backing out the deallocation, we will have
2034 * to back split the dmap tree if the deallocation caused
2035 * the freed blocks to become part of a larger binary buddy
2036 * system.
2037 */
2038 if (dp->tree.stree[word] == NOFREE)
2039 dbBackSplit((dmtree_t *) & dp->tree, word);
2040
2041 dbAllocBits(bmp, dp, blkno, nblocks);
2042 }
2043
2044 return (rc);
2045}
2046
2047
2048/*
2049 * NAME: dbAllocBits()
2050 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002051 * FUNCTION: allocate a specified block range from a dmap.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002052 *
2053 * this routine updates the dmap to reflect the working
2054 * state allocation of the specified block range. it directly
2055 * updates the bits of the working map and causes the adjustment
2056 * of the binary buddy system described by the dmap's dmtree
2057 * leaves to reflect the bits allocated. it also causes the
2058 * dmap's dmtree, as a whole, to reflect the allocated range.
2059 *
2060 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002061 * bmp - pointer to bmap descriptor
2062 * dp - pointer to dmap to allocate bits from.
2063 * blkno - starting block number of the bits to be allocated.
2064 * nblocks - number of bits to be allocated.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002065 *
2066 * RETURN VALUES: none
2067 *
2068 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2069 */
2070static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2071 int nblocks)
2072{
2073 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2074 dmtree_t *tp = (dmtree_t *) & dp->tree;
2075 int size;
2076 s8 *leaf;
2077
2078 /* pick up a pointer to the leaves of the dmap tree */
2079 leaf = dp->tree.stree + LEAFIND;
2080
2081 /* determine the bit number and word within the dmap of the
2082 * starting block.
2083 */
2084 dbitno = blkno & (BPERDMAP - 1);
2085 word = dbitno >> L2DBWORD;
2086
2087 /* block range better be within the dmap */
2088 assert(dbitno + nblocks <= BPERDMAP);
2089
2090 /* allocate the bits of the dmap's words corresponding to the block
2091 * range. not all bits of the first and last words may be contained
2092 * within the block range. if this is the case, we'll work against
2093 * those words (i.e. partial first and/or last) on an individual basis
2094 * (a single pass), allocating the bits of interest by hand and
2095 * updating the leaf corresponding to the dmap word. a single pass
2096 * will be used for all dmap words fully contained within the
2097 * specified range. within this pass, the bits of all fully contained
2098 * dmap words will be marked as free in a single shot and the leaves
2099 * will be updated. a single leaf may describe the free space of
2100 * multiple dmap words, so we may update only a subset of the actual
2101 * leaves corresponding to the dmap words of the block range.
2102 */
2103 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2104 /* determine the bit number within the word and
2105 * the number of bits within the word.
2106 */
2107 wbitno = dbitno & (DBWORD - 1);
2108 nb = min(rembits, DBWORD - wbitno);
2109
2110 /* check if only part of a word is to be allocated.
2111 */
2112 if (nb < DBWORD) {
2113 /* allocate (set to 1) the appropriate bits within
2114 * this dmap word.
2115 */
2116 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
2117 >> wbitno);
2118
2119 /* update the leaf for this dmap word. in addition
2120 * to setting the leaf value to the binary buddy max
2121 * of the updated dmap word, dbSplit() will split
2122 * the binary system of the leaves if need be.
2123 */
2124 dbSplit(tp, word, BUDMIN,
2125 dbMaxBud((u8 *) & dp->wmap[word]));
2126
2127 word += 1;
2128 } else {
2129 /* one or more dmap words are fully contained
2130 * within the block range. determine how many
2131 * words and allocate (set to 1) the bits of these
2132 * words.
2133 */
2134 nwords = rembits >> L2DBWORD;
2135 memset(&dp->wmap[word], (int) ONES, nwords * 4);
2136
2137 /* determine how many bits.
2138 */
2139 nb = nwords << L2DBWORD;
2140
2141 /* now update the appropriate leaves to reflect
2142 * the allocated words.
2143 */
2144 for (; nwords > 0; nwords -= nw) {
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002145 if (leaf[word] < BUDMIN) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002146 jfs_error(bmp->db_ipbmap->i_sb,
2147 "dbAllocBits: leaf page "
2148 "corrupt");
2149 break;
2150 }
2151
2152 /* determine what the leaf value should be
2153 * updated to as the minimum of the l2 number
2154 * of bits being allocated and the l2 number
2155 * of bits currently described by this leaf.
2156 */
2157 size = min((int)leaf[word], NLSTOL2BSZ(nwords));
2158
2159 /* update the leaf to reflect the allocation.
2160 * in addition to setting the leaf value to
2161 * NOFREE, dbSplit() will split the binary
2162 * system of the leaves to reflect the current
2163 * allocation (size).
2164 */
2165 dbSplit(tp, word, size, NOFREE);
2166
2167 /* get the number of dmap words handled */
2168 nw = BUDSIZE(size, BUDMIN);
2169 word += nw;
2170 }
2171 }
2172 }
2173
2174 /* update the free count for this dmap */
2175 dp->nfree = cpu_to_le32(le32_to_cpu(dp->nfree) - nblocks);
2176
2177 BMAP_LOCK(bmp);
2178
2179 /* if this allocation group is completely free,
2180 * update the maximum allocation group number if this allocation
2181 * group is the new max.
2182 */
2183 agno = blkno >> bmp->db_agl2size;
2184 if (agno > bmp->db_maxag)
2185 bmp->db_maxag = agno;
2186
2187 /* update the free count for the allocation group and map */
2188 bmp->db_agfree[agno] -= nblocks;
2189 bmp->db_nfree -= nblocks;
2190
2191 BMAP_UNLOCK(bmp);
2192}
2193
2194
2195/*
2196 * NAME: dbFreeBits()
2197 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002198 * FUNCTION: free a specified block range from a dmap.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002199 *
2200 * this routine updates the dmap to reflect the working
2201 * state allocation of the specified block range. it directly
2202 * updates the bits of the working map and causes the adjustment
2203 * of the binary buddy system described by the dmap's dmtree
2204 * leaves to reflect the bits freed. it also causes the dmap's
2205 * dmtree, as a whole, to reflect the deallocated range.
2206 *
2207 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002208 * bmp - pointer to bmap descriptor
2209 * dp - pointer to dmap to free bits from.
2210 * blkno - starting block number of the bits to be freed.
2211 * nblocks - number of bits to be freed.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002212 *
Dave Kleikamp56d12542005-07-15 09:43:36 -05002213 * RETURN VALUES: 0 for success
Linus Torvalds1da177e2005-04-16 15:20:36 -07002214 *
2215 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2216 */
Dave Kleikamp56d12542005-07-15 09:43:36 -05002217static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002218 int nblocks)
2219{
2220 int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2221 dmtree_t *tp = (dmtree_t *) & dp->tree;
Dave Kleikamp56d12542005-07-15 09:43:36 -05002222 int rc = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002223 int size;
2224
2225 /* determine the bit number and word within the dmap of the
2226 * starting block.
2227 */
2228 dbitno = blkno & (BPERDMAP - 1);
2229 word = dbitno >> L2DBWORD;
2230
2231 /* block range better be within the dmap.
2232 */
2233 assert(dbitno + nblocks <= BPERDMAP);
2234
2235 /* free the bits of the dmaps words corresponding to the block range.
2236 * not all bits of the first and last words may be contained within
2237 * the block range. if this is the case, we'll work against those
2238 * words (i.e. partial first and/or last) on an individual basis
2239 * (a single pass), freeing the bits of interest by hand and updating
2240 * the leaf corresponding to the dmap word. a single pass will be used
Dave Kleikamp63f83c92006-10-02 09:55:27 -05002241 * for all dmap words fully contained within the specified range.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002242 * within this pass, the bits of all fully contained dmap words will
2243 * be marked as free in a single shot and the leaves will be updated. a
2244 * single leaf may describe the free space of multiple dmap words,
2245 * so we may update only a subset of the actual leaves corresponding
2246 * to the dmap words of the block range.
2247 *
2248 * dbJoin() is used to update leaf values and will join the binary
2249 * buddy system of the leaves if the new leaf values indicate this
2250 * should be done.
2251 */
2252 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2253 /* determine the bit number within the word and
2254 * the number of bits within the word.
2255 */
2256 wbitno = dbitno & (DBWORD - 1);
2257 nb = min(rembits, DBWORD - wbitno);
2258
2259 /* check if only part of a word is to be freed.
2260 */
2261 if (nb < DBWORD) {
2262 /* free (zero) the appropriate bits within this
Dave Kleikamp63f83c92006-10-02 09:55:27 -05002263 * dmap word.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002264 */
2265 dp->wmap[word] &=
2266 cpu_to_le32(~(ONES << (DBWORD - nb)
2267 >> wbitno));
2268
2269 /* update the leaf for this dmap word.
2270 */
Dave Kleikamp56d12542005-07-15 09:43:36 -05002271 rc = dbJoin(tp, word,
2272 dbMaxBud((u8 *) & dp->wmap[word]));
2273 if (rc)
2274 return rc;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002275
2276 word += 1;
2277 } else {
2278 /* one or more dmap words are fully contained
2279 * within the block range. determine how many
2280 * words and free (zero) the bits of these words.
2281 */
2282 nwords = rembits >> L2DBWORD;
2283 memset(&dp->wmap[word], 0, nwords * 4);
2284
2285 /* determine how many bits.
2286 */
2287 nb = nwords << L2DBWORD;
2288
2289 /* now update the appropriate leaves to reflect
2290 * the freed words.
2291 */
2292 for (; nwords > 0; nwords -= nw) {
2293 /* determine what the leaf value should be
2294 * updated to as the minimum of the l2 number
2295 * of bits being freed and the l2 (max) number
2296 * of bits that can be described by this leaf.
2297 */
2298 size =
2299 min(LITOL2BSZ
2300 (word, L2LPERDMAP, BUDMIN),
2301 NLSTOL2BSZ(nwords));
2302
2303 /* update the leaf.
2304 */
Dave Kleikamp56d12542005-07-15 09:43:36 -05002305 rc = dbJoin(tp, word, size);
2306 if (rc)
2307 return rc;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002308
2309 /* get the number of dmap words handled.
2310 */
2311 nw = BUDSIZE(size, BUDMIN);
2312 word += nw;
2313 }
2314 }
2315 }
2316
2317 /* update the free count for this dmap.
2318 */
2319 dp->nfree = cpu_to_le32(le32_to_cpu(dp->nfree) + nblocks);
2320
2321 BMAP_LOCK(bmp);
2322
Dave Kleikamp63f83c92006-10-02 09:55:27 -05002323 /* update the free count for the allocation group and
Linus Torvalds1da177e2005-04-16 15:20:36 -07002324 * map.
2325 */
2326 agno = blkno >> bmp->db_agl2size;
2327 bmp->db_nfree += nblocks;
2328 bmp->db_agfree[agno] += nblocks;
2329
2330 /* check if this allocation group is not completely free and
2331 * if it is currently the maximum (rightmost) allocation group.
2332 * if so, establish the new maximum allocation group number by
2333 * searching left for the first allocation group with allocation.
2334 */
2335 if ((bmp->db_agfree[agno] == bmp->db_agsize && agno == bmp->db_maxag) ||
2336 (agno == bmp->db_numag - 1 &&
2337 bmp->db_agfree[agno] == (bmp-> db_mapsize & (BPERDMAP - 1)))) {
2338 while (bmp->db_maxag > 0) {
2339 bmp->db_maxag -= 1;
2340 if (bmp->db_agfree[bmp->db_maxag] !=
2341 bmp->db_agsize)
2342 break;
2343 }
2344
2345 /* re-establish the allocation group preference if the
2346 * current preference is right of the maximum allocation
2347 * group.
2348 */
2349 if (bmp->db_agpref > bmp->db_maxag)
2350 bmp->db_agpref = bmp->db_maxag;
2351 }
2352
2353 BMAP_UNLOCK(bmp);
Dave Kleikamp56d12542005-07-15 09:43:36 -05002354
2355 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002356}
2357
2358
2359/*
2360 * NAME: dbAdjCtl()
2361 *
2362 * FUNCTION: adjust a dmap control page at a specified level to reflect
2363 * the change in a lower level dmap or dmap control page's
2364 * maximum string of free blocks (i.e. a change in the root
2365 * of the lower level object's dmtree) due to the allocation
2366 * or deallocation of a range of blocks with a single dmap.
2367 *
2368 * on entry, this routine is provided with the new value of
2369 * the lower level dmap or dmap control page root and the
2370 * starting block number of the block range whose allocation
2371 * or deallocation resulted in the root change. this range
2372 * is respresented by a single leaf of the current dmapctl
2373 * and the leaf will be updated with this value, possibly
Dave Kleikamp63f83c92006-10-02 09:55:27 -05002374 * causing a binary buddy system within the leaves to be
Linus Torvalds1da177e2005-04-16 15:20:36 -07002375 * split or joined. the update may also cause the dmapctl's
2376 * dmtree to be updated.
2377 *
2378 * if the adjustment of the dmap control page, itself, causes its
2379 * root to change, this change will be bubbled up to the next dmap
2380 * control level by a recursive call to this routine, specifying
2381 * the new root value and the next dmap control page level to
2382 * be adjusted.
2383 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002384 * bmp - pointer to bmap descriptor
2385 * blkno - the first block of a block range within a dmap. it is
Linus Torvalds1da177e2005-04-16 15:20:36 -07002386 * the allocation or deallocation of this block range that
2387 * requires the dmap control page to be adjusted.
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002388 * newval - the new value of the lower level dmap or dmap control
Linus Torvalds1da177e2005-04-16 15:20:36 -07002389 * page root.
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002390 * alloc - 'true' if adjustment is due to an allocation.
2391 * level - current level of dmap control page (i.e. L0, L1, L2) to
Linus Torvalds1da177e2005-04-16 15:20:36 -07002392 * be adjusted.
2393 *
2394 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002395 * 0 - success
2396 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -07002397 *
2398 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2399 */
2400static int
2401dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, int level)
2402{
2403 struct metapage *mp;
2404 s8 oldroot;
2405 int oldval;
2406 s64 lblkno;
2407 struct dmapctl *dcp;
2408 int rc, leafno, ti;
2409
2410 /* get the buffer for the dmap control page for the specified
2411 * block number and control page level.
2412 */
2413 lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, level);
2414 mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
2415 if (mp == NULL)
2416 return -EIO;
2417 dcp = (struct dmapctl *) mp->data;
2418
2419 if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
2420 jfs_error(bmp->db_ipbmap->i_sb,
2421 "dbAdjCtl: Corrupt dmapctl page");
2422 release_metapage(mp);
2423 return -EIO;
2424 }
2425
2426 /* determine the leaf number corresponding to the block and
2427 * the index within the dmap control tree.
2428 */
2429 leafno = BLKTOCTLLEAF(blkno, dcp->budmin);
2430 ti = leafno + le32_to_cpu(dcp->leafidx);
2431
2432 /* save the current leaf value and the current root level (i.e.
2433 * maximum l2 free string described by this dmapctl).
2434 */
2435 oldval = dcp->stree[ti];
2436 oldroot = dcp->stree[ROOT];
2437
2438 /* check if this is a control page update for an allocation.
2439 * if so, update the leaf to reflect the new leaf value using
2440 * dbSplit(); otherwise (deallocation), use dbJoin() to udpate
2441 * the leaf with the new value. in addition to updating the
2442 * leaf, dbSplit() will also split the binary buddy system of
2443 * the leaves, if required, and bubble new values within the
2444 * dmapctl tree, if required. similarly, dbJoin() will join
2445 * the binary buddy system of leaves and bubble new values up
2446 * the dmapctl tree as required by the new leaf value.
2447 */
2448 if (alloc) {
2449 /* check if we are in the middle of a binary buddy
2450 * system. this happens when we are performing the
2451 * first allocation out of an allocation group that
2452 * is part (not the first part) of a larger binary
2453 * buddy system. if we are in the middle, back split
2454 * the system prior to calling dbSplit() which assumes
2455 * that it is at the front of a binary buddy system.
2456 */
2457 if (oldval == NOFREE) {
Dave Kleikampb6a47fd2005-10-11 09:06:59 -05002458 rc = dbBackSplit((dmtree_t *) dcp, leafno);
2459 if (rc)
2460 return rc;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002461 oldval = dcp->stree[ti];
2462 }
2463 dbSplit((dmtree_t *) dcp, leafno, dcp->budmin, newval);
2464 } else {
Dave Kleikamp56d12542005-07-15 09:43:36 -05002465 rc = dbJoin((dmtree_t *) dcp, leafno, newval);
2466 if (rc)
2467 return rc;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002468 }
2469
2470 /* check if the root of the current dmap control page changed due
2471 * to the update and if the current dmap control page is not at
2472 * the current top level (i.e. L0, L1, L2) of the map. if so (i.e.
2473 * root changed and this is not the top level), call this routine
2474 * again (recursion) for the next higher level of the mapping to
2475 * reflect the change in root for the current dmap control page.
2476 */
2477 if (dcp->stree[ROOT] != oldroot) {
2478 /* are we below the top level of the map. if so,
2479 * bubble the root up to the next higher level.
2480 */
2481 if (level < bmp->db_maxlevel) {
2482 /* bubble up the new root of this dmap control page to
2483 * the next level.
2484 */
2485 if ((rc =
2486 dbAdjCtl(bmp, blkno, dcp->stree[ROOT], alloc,
2487 level + 1))) {
2488 /* something went wrong in bubbling up the new
2489 * root value, so backout the changes to the
2490 * current dmap control page.
2491 */
2492 if (alloc) {
2493 dbJoin((dmtree_t *) dcp, leafno,
2494 oldval);
2495 } else {
2496 /* the dbJoin() above might have
2497 * caused a larger binary buddy system
2498 * to form and we may now be in the
2499 * middle of it. if this is the case,
2500 * back split the buddies.
2501 */
2502 if (dcp->stree[ti] == NOFREE)
2503 dbBackSplit((dmtree_t *)
2504 dcp, leafno);
2505 dbSplit((dmtree_t *) dcp, leafno,
2506 dcp->budmin, oldval);
2507 }
2508
2509 /* release the buffer and return the error.
2510 */
2511 release_metapage(mp);
2512 return (rc);
2513 }
2514 } else {
2515 /* we're at the top level of the map. update
2516 * the bmap control page to reflect the size
2517 * of the maximum free buddy system.
2518 */
2519 assert(level == bmp->db_maxlevel);
2520 if (bmp->db_maxfreebud != oldroot) {
2521 jfs_error(bmp->db_ipbmap->i_sb,
2522 "dbAdjCtl: the maximum free buddy is "
2523 "not the old root");
2524 }
2525 bmp->db_maxfreebud = dcp->stree[ROOT];
2526 }
2527 }
2528
2529 /* write the buffer.
2530 */
2531 write_metapage(mp);
2532
2533 return (0);
2534}
2535
2536
2537/*
2538 * NAME: dbSplit()
2539 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002540 * FUNCTION: update the leaf of a dmtree with a new value, splitting
Linus Torvalds1da177e2005-04-16 15:20:36 -07002541 * the leaf from the binary buddy system of the dmtree's
2542 * leaves, as required.
2543 *
2544 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002545 * tp - pointer to the tree containing the leaf.
2546 * leafno - the number of the leaf to be updated.
2547 * splitsz - the size the binary buddy system starting at the leaf
Linus Torvalds1da177e2005-04-16 15:20:36 -07002548 * must be split to, specified as the log2 number of blocks.
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002549 * newval - the new value for the leaf.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002550 *
2551 * RETURN VALUES: none
2552 *
2553 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2554 */
2555static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval)
2556{
2557 int budsz;
2558 int cursz;
2559 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2560
2561 /* check if the leaf needs to be split.
2562 */
2563 if (leaf[leafno] > tp->dmt_budmin) {
2564 /* the split occurs by cutting the buddy system in half
2565 * at the specified leaf until we reach the specified
2566 * size. pick up the starting split size (current size
2567 * - 1 in l2) and the corresponding buddy size.
2568 */
2569 cursz = leaf[leafno] - 1;
2570 budsz = BUDSIZE(cursz, tp->dmt_budmin);
2571
2572 /* split until we reach the specified size.
2573 */
2574 while (cursz >= splitsz) {
2575 /* update the buddy's leaf with its new value.
2576 */
2577 dbAdjTree(tp, leafno ^ budsz, cursz);
2578
2579 /* on to the next size and buddy.
2580 */
2581 cursz -= 1;
2582 budsz >>= 1;
2583 }
2584 }
2585
Dave Kleikamp63f83c92006-10-02 09:55:27 -05002586 /* adjust the dmap tree to reflect the specified leaf's new
Linus Torvalds1da177e2005-04-16 15:20:36 -07002587 * value.
2588 */
2589 dbAdjTree(tp, leafno, newval);
2590}
2591
2592
2593/*
2594 * NAME: dbBackSplit()
2595 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002596 * FUNCTION: back split the binary buddy system of dmtree leaves
Linus Torvalds1da177e2005-04-16 15:20:36 -07002597 * that hold a specified leaf until the specified leaf
2598 * starts its own binary buddy system.
2599 *
2600 * the allocators typically perform allocations at the start
2601 * of binary buddy systems and dbSplit() is used to accomplish
2602 * any required splits. in some cases, however, allocation
2603 * may occur in the middle of a binary system and requires a
2604 * back split, with the split proceeding out from the middle of
2605 * the system (less efficient) rather than the start of the
2606 * system (more efficient). the cases in which a back split
2607 * is required are rare and are limited to the first allocation
2608 * within an allocation group which is a part (not first part)
2609 * of a larger binary buddy system and a few exception cases
2610 * in which a previous join operation must be backed out.
2611 *
2612 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002613 * tp - pointer to the tree containing the leaf.
2614 * leafno - the number of the leaf to be updated.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002615 *
2616 * RETURN VALUES: none
2617 *
2618 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2619 */
Dave Kleikampb6a47fd2005-10-11 09:06:59 -05002620static int dbBackSplit(dmtree_t * tp, int leafno)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002621{
2622 int budsz, bud, w, bsz, size;
2623 int cursz;
2624 s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2625
2626 /* leaf should be part (not first part) of a binary
2627 * buddy system.
2628 */
2629 assert(leaf[leafno] == NOFREE);
2630
2631 /* the back split is accomplished by iteratively finding the leaf
2632 * that starts the buddy system that contains the specified leaf and
2633 * splitting that system in two. this iteration continues until
Dave Kleikamp63f83c92006-10-02 09:55:27 -05002634 * the specified leaf becomes the start of a buddy system.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002635 *
2636 * determine maximum possible l2 size for the specified leaf.
2637 */
2638 size =
2639 LITOL2BSZ(leafno, le32_to_cpu(tp->dmt_l2nleafs),
2640 tp->dmt_budmin);
2641
2642 /* determine the number of leaves covered by this size. this
2643 * is the buddy size that we will start with as we search for
2644 * the buddy system that contains the specified leaf.
2645 */
2646 budsz = BUDSIZE(size, tp->dmt_budmin);
2647
2648 /* back split.
2649 */
2650 while (leaf[leafno] == NOFREE) {
2651 /* find the leftmost buddy leaf.
2652 */
2653 for (w = leafno, bsz = budsz;; bsz <<= 1,
2654 w = (w < bud) ? w : bud) {
Dave Kleikampb6a47fd2005-10-11 09:06:59 -05002655 if (bsz >= le32_to_cpu(tp->dmt_nleafs)) {
2656 jfs_err("JFS: block map error in dbBackSplit");
2657 return -EIO;
2658 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002659
2660 /* determine the buddy.
2661 */
2662 bud = w ^ bsz;
2663
2664 /* check if this buddy is the start of the system.
2665 */
2666 if (leaf[bud] != NOFREE) {
2667 /* split the leaf at the start of the
2668 * system in two.
2669 */
2670 cursz = leaf[bud] - 1;
2671 dbSplit(tp, bud, cursz, cursz);
2672 break;
2673 }
2674 }
2675 }
2676
Dave Kleikampb6a47fd2005-10-11 09:06:59 -05002677 if (leaf[leafno] != size) {
2678 jfs_err("JFS: wrong leaf value in dbBackSplit");
2679 return -EIO;
2680 }
2681 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002682}
2683
2684
2685/*
2686 * NAME: dbJoin()
2687 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002688 * FUNCTION: update the leaf of a dmtree with a new value, joining
Linus Torvalds1da177e2005-04-16 15:20:36 -07002689 * the leaf with other leaves of the dmtree into a multi-leaf
2690 * binary buddy system, as required.
2691 *
2692 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002693 * tp - pointer to the tree containing the leaf.
2694 * leafno - the number of the leaf to be updated.
2695 * newval - the new value for the leaf.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002696 *
2697 * RETURN VALUES: none
2698 */
Dave Kleikamp56d12542005-07-15 09:43:36 -05002699static int dbJoin(dmtree_t * tp, int leafno, int newval)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002700{
2701 int budsz, buddy;
2702 s8 *leaf;
2703
2704 /* can the new leaf value require a join with other leaves ?
2705 */
2706 if (newval >= tp->dmt_budmin) {
2707 /* pickup a pointer to the leaves of the tree.
2708 */
2709 leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2710
2711 /* try to join the specified leaf into a large binary
2712 * buddy system. the join proceeds by attempting to join
2713 * the specified leafno with its buddy (leaf) at new value.
2714 * if the join occurs, we attempt to join the left leaf
2715 * of the joined buddies with its buddy at new value + 1.
2716 * we continue to join until we find a buddy that cannot be
2717 * joined (does not have a value equal to the size of the
2718 * last join) or until all leaves have been joined into a
2719 * single system.
2720 *
2721 * get the buddy size (number of words covered) of
2722 * the new value.
2723 */
2724 budsz = BUDSIZE(newval, tp->dmt_budmin);
2725
2726 /* try to join.
2727 */
2728 while (budsz < le32_to_cpu(tp->dmt_nleafs)) {
2729 /* get the buddy leaf.
2730 */
2731 buddy = leafno ^ budsz;
2732
2733 /* if the leaf's new value is greater than its
2734 * buddy's value, we join no more.
2735 */
2736 if (newval > leaf[buddy])
2737 break;
2738
Dave Kleikamp56d12542005-07-15 09:43:36 -05002739 /* It shouldn't be less */
2740 if (newval < leaf[buddy])
2741 return -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002742
2743 /* check which (leafno or buddy) is the left buddy.
2744 * the left buddy gets to claim the blocks resulting
2745 * from the join while the right gets to claim none.
2746 * the left buddy is also eligable to participate in
2747 * a join at the next higher level while the right
2748 * is not.
2749 *
2750 */
2751 if (leafno < buddy) {
2752 /* leafno is the left buddy.
2753 */
2754 dbAdjTree(tp, buddy, NOFREE);
2755 } else {
2756 /* buddy is the left buddy and becomes
2757 * leafno.
2758 */
2759 dbAdjTree(tp, leafno, NOFREE);
2760 leafno = buddy;
2761 }
2762
2763 /* on to try the next join.
2764 */
2765 newval += 1;
2766 budsz <<= 1;
2767 }
2768 }
2769
2770 /* update the leaf value.
2771 */
2772 dbAdjTree(tp, leafno, newval);
Dave Kleikamp56d12542005-07-15 09:43:36 -05002773
2774 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002775}
2776
2777
2778/*
2779 * NAME: dbAdjTree()
2780 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002781 * FUNCTION: update a leaf of a dmtree with a new value, adjusting
Linus Torvalds1da177e2005-04-16 15:20:36 -07002782 * the dmtree, as required, to reflect the new leaf value.
2783 * the combination of any buddies must already be done before
2784 * this is called.
2785 *
2786 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002787 * tp - pointer to the tree to be adjusted.
2788 * leafno - the number of the leaf to be updated.
2789 * newval - the new value for the leaf.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002790 *
2791 * RETURN VALUES: none
2792 */
2793static void dbAdjTree(dmtree_t * tp, int leafno, int newval)
2794{
2795 int lp, pp, k;
2796 int max;
2797
2798 /* pick up the index of the leaf for this leafno.
2799 */
2800 lp = leafno + le32_to_cpu(tp->dmt_leafidx);
2801
2802 /* is the current value the same as the old value ? if so,
2803 * there is nothing to do.
2804 */
2805 if (tp->dmt_stree[lp] == newval)
2806 return;
2807
2808 /* set the new value.
2809 */
2810 tp->dmt_stree[lp] = newval;
2811
2812 /* bubble the new value up the tree as required.
2813 */
2814 for (k = 0; k < le32_to_cpu(tp->dmt_height); k++) {
2815 /* get the index of the first leaf of the 4 leaf
2816 * group containing the specified leaf (leafno).
2817 */
2818 lp = ((lp - 1) & ~0x03) + 1;
2819
2820 /* get the index of the parent of this 4 leaf group.
2821 */
2822 pp = (lp - 1) >> 2;
2823
2824 /* determine the maximum of the 4 leaves.
2825 */
2826 max = TREEMAX(&tp->dmt_stree[lp]);
2827
2828 /* if the maximum of the 4 is the same as the
2829 * parent's value, we're done.
2830 */
2831 if (tp->dmt_stree[pp] == max)
2832 break;
2833
2834 /* parent gets new value.
2835 */
2836 tp->dmt_stree[pp] = max;
2837
2838 /* parent becomes leaf for next go-round.
2839 */
2840 lp = pp;
2841 }
2842}
2843
2844
2845/*
2846 * NAME: dbFindLeaf()
2847 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002848 * FUNCTION: search a dmtree_t for sufficient free blocks, returning
Dave Kleikamp63f83c92006-10-02 09:55:27 -05002849 * the index of a leaf describing the free blocks if
Linus Torvalds1da177e2005-04-16 15:20:36 -07002850 * sufficient free blocks are found.
2851 *
2852 * the search starts at the top of the dmtree_t tree and
2853 * proceeds down the tree to the leftmost leaf with sufficient
2854 * free space.
2855 *
2856 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002857 * tp - pointer to the tree to be searched.
2858 * l2nb - log2 number of free blocks to search for.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002859 * leafidx - return pointer to be set to the index of the leaf
2860 * describing at least l2nb free blocks if sufficient
2861 * free blocks are found.
2862 *
2863 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002864 * 0 - success
2865 * -ENOSPC - insufficient free blocks.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002866 */
2867static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx)
2868{
2869 int ti, n = 0, k, x = 0;
2870
2871 /* first check the root of the tree to see if there is
2872 * sufficient free space.
2873 */
2874 if (l2nb > tp->dmt_stree[ROOT])
2875 return -ENOSPC;
2876
2877 /* sufficient free space available. now search down the tree
2878 * starting at the next level for the leftmost leaf that
2879 * describes sufficient free space.
2880 */
2881 for (k = le32_to_cpu(tp->dmt_height), ti = 1;
2882 k > 0; k--, ti = ((ti + n) << 2) + 1) {
2883 /* search the four nodes at this level, starting from
2884 * the left.
2885 */
2886 for (x = ti, n = 0; n < 4; n++) {
2887 /* sufficient free space found. move to the next
2888 * level (or quit if this is the last level).
2889 */
2890 if (l2nb <= tp->dmt_stree[x + n])
2891 break;
2892 }
2893
2894 /* better have found something since the higher
2895 * levels of the tree said it was here.
2896 */
2897 assert(n < 4);
2898 }
2899
2900 /* set the return to the leftmost leaf describing sufficient
2901 * free space.
2902 */
2903 *leafidx = x + n - le32_to_cpu(tp->dmt_leafidx);
2904
2905 return (0);
2906}
2907
2908
2909/*
2910 * NAME: dbFindBits()
2911 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002912 * FUNCTION: find a specified number of binary buddy free bits within a
Linus Torvalds1da177e2005-04-16 15:20:36 -07002913 * dmap bitmap word value.
2914 *
2915 * this routine searches the bitmap value for (1 << l2nb) free
2916 * bits at (1 << l2nb) alignments within the value.
2917 *
2918 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002919 * word - dmap bitmap word value.
2920 * l2nb - number of free bits specified as a log2 number.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002921 *
2922 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002923 * starting bit number of free bits.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002924 */
2925static int dbFindBits(u32 word, int l2nb)
2926{
2927 int bitno, nb;
2928 u32 mask;
2929
2930 /* get the number of bits.
2931 */
2932 nb = 1 << l2nb;
2933 assert(nb <= DBWORD);
2934
2935 /* complement the word so we can use a mask (i.e. 0s represent
2936 * free bits) and compute the mask.
2937 */
2938 word = ~word;
2939 mask = ONES << (DBWORD - nb);
2940
2941 /* scan the word for nb free bits at nb alignments.
2942 */
2943 for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) {
2944 if ((mask & word) == mask)
2945 break;
2946 }
2947
2948 ASSERT(bitno < 32);
2949
2950 /* return the bit number.
2951 */
2952 return (bitno);
2953}
2954
2955
2956/*
2957 * NAME: dbMaxBud(u8 *cp)
2958 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002959 * FUNCTION: determine the largest binary buddy string of free
Linus Torvalds1da177e2005-04-16 15:20:36 -07002960 * bits within 32-bits of the map.
2961 *
2962 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002963 * cp - pointer to the 32-bit value.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002964 *
2965 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002966 * largest binary buddy of free bits within a dmap word.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002967 */
2968static int dbMaxBud(u8 * cp)
2969{
2970 signed char tmp1, tmp2;
2971
2972 /* check if the wmap word is all free. if so, the
2973 * free buddy size is BUDMIN.
2974 */
2975 if (*((uint *) cp) == 0)
2976 return (BUDMIN);
2977
2978 /* check if the wmap word is half free. if so, the
2979 * free buddy size is BUDMIN-1.
2980 */
2981 if (*((u16 *) cp) == 0 || *((u16 *) cp + 1) == 0)
2982 return (BUDMIN - 1);
2983
2984 /* not all free or half free. determine the free buddy
2985 * size thru table lookup using quarters of the wmap word.
2986 */
2987 tmp1 = max(budtab[cp[2]], budtab[cp[3]]);
2988 tmp2 = max(budtab[cp[0]], budtab[cp[1]]);
2989 return (max(tmp1, tmp2));
2990}
2991
2992
2993/*
2994 * NAME: cnttz(uint word)
2995 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05002996 * FUNCTION: determine the number of trailing zeros within a 32-bit
Linus Torvalds1da177e2005-04-16 15:20:36 -07002997 * value.
2998 *
2999 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003000 * value - 32-bit value to be examined.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003001 *
3002 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003003 * count of trailing zeros
Linus Torvalds1da177e2005-04-16 15:20:36 -07003004 */
3005static int cnttz(u32 word)
3006{
3007 int n;
3008
3009 for (n = 0; n < 32; n++, word >>= 1) {
3010 if (word & 0x01)
3011 break;
3012 }
3013
3014 return (n);
3015}
3016
3017
3018/*
3019 * NAME: cntlz(u32 value)
3020 *
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003021 * FUNCTION: determine the number of leading zeros within a 32-bit
Linus Torvalds1da177e2005-04-16 15:20:36 -07003022 * value.
3023 *
3024 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003025 * value - 32-bit value to be examined.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003026 *
3027 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003028 * count of leading zeros
Linus Torvalds1da177e2005-04-16 15:20:36 -07003029 */
3030static int cntlz(u32 value)
3031{
3032 int n;
3033
3034 for (n = 0; n < 32; n++, value <<= 1) {
3035 if (value & HIGHORDER)
3036 break;
3037 }
3038 return (n);
3039}
3040
3041
3042/*
3043 * NAME: blkstol2(s64 nb)
3044 *
3045 * FUNCTION: convert a block count to its log2 value. if the block
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003046 * count is not a l2 multiple, it is rounded up to the next
Linus Torvalds1da177e2005-04-16 15:20:36 -07003047 * larger l2 multiple.
3048 *
3049 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003050 * nb - number of blocks
Linus Torvalds1da177e2005-04-16 15:20:36 -07003051 *
3052 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003053 * log2 number of blocks
Linus Torvalds1da177e2005-04-16 15:20:36 -07003054 */
Dave Kleikamp6cb12692005-09-15 23:25:41 -05003055static int blkstol2(s64 nb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003056{
3057 int l2nb;
3058 s64 mask; /* meant to be signed */
3059
3060 mask = (s64) 1 << (64 - 1);
3061
3062 /* count the leading bits.
3063 */
3064 for (l2nb = 0; l2nb < 64; l2nb++, mask >>= 1) {
3065 /* leading bit found.
3066 */
3067 if (nb & mask) {
3068 /* determine the l2 value.
3069 */
3070 l2nb = (64 - 1) - l2nb;
3071
3072 /* check if we need to round up.
3073 */
3074 if (~mask & nb)
3075 l2nb++;
3076
3077 return (l2nb);
3078 }
3079 }
3080 assert(0);
3081 return 0; /* fix compiler warning */
3082}
3083
3084
3085/*
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003086 * NAME: dbAllocBottomUp()
Linus Torvalds1da177e2005-04-16 15:20:36 -07003087 *
3088 * FUNCTION: alloc the specified block range from the working block
3089 * allocation map.
3090 *
3091 * the blocks will be alloc from the working map one dmap
3092 * at a time.
3093 *
3094 * PARAMETERS:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003095 * ip - pointer to in-core inode;
3096 * blkno - starting block number to be freed.
3097 * nblocks - number of blocks to be freed.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003098 *
3099 * RETURN VALUES:
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003100 * 0 - success
3101 * -EIO - i/o error
Linus Torvalds1da177e2005-04-16 15:20:36 -07003102 */
3103int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks)
3104{
3105 struct metapage *mp;
3106 struct dmap *dp;
3107 int nb, rc;
3108 s64 lblkno, rem;
3109 struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
3110 struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
3111
Dave Kleikamp82d5b9a2007-01-09 14:14:48 -06003112 IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003113
3114 /* block to be allocated better be within the mapsize. */
3115 ASSERT(nblocks <= bmp->db_mapsize - blkno);
3116
3117 /*
3118 * allocate the blocks a dmap at a time.
3119 */
3120 mp = NULL;
3121 for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
3122 /* release previous dmap if any */
3123 if (mp) {
3124 write_metapage(mp);
3125 }
3126
3127 /* get the buffer for the current dmap. */
3128 lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
3129 mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
3130 if (mp == NULL) {
3131 IREAD_UNLOCK(ipbmap);
3132 return -EIO;
3133 }
3134 dp = (struct dmap *) mp->data;
3135
3136 /* determine the number of blocks to be allocated from
3137 * this dmap.
3138 */
3139 nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
3140
Linus Torvalds1da177e2005-04-16 15:20:36 -07003141 /* allocate the blocks. */
3142 if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) {
3143 release_metapage(mp);
3144 IREAD_UNLOCK(ipbmap);
3145 return (rc);
3146 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07003147 }
3148
3149 /* write the last buffer. */
3150 write_metapage(mp);
3151
3152 IREAD_UNLOCK(ipbmap);
3153
3154 return (0);
3155}
3156
3157
3158static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
3159 int nblocks)
3160{
3161 int rc;
3162 int dbitno, word, rembits, nb, nwords, wbitno, agno;
3163 s8 oldroot, *leaf;
3164 struct dmaptree *tp = (struct dmaptree *) & dp->tree;
3165
3166 /* save the current value of the root (i.e. maximum free string)
3167 * of the dmap tree.
3168 */
3169 oldroot = tp->stree[ROOT];
3170
3171 /* pick up a pointer to the leaves of the dmap tree */
3172 leaf = tp->stree + LEAFIND;
3173
3174 /* determine the bit number and word within the dmap of the
3175 * starting block.
3176 */
3177 dbitno = blkno & (BPERDMAP - 1);
3178 word = dbitno >> L2DBWORD;
3179
3180 /* block range better be within the dmap */
3181 assert(dbitno + nblocks <= BPERDMAP);
3182
3183 /* allocate the bits of the dmap's words corresponding to the block
3184 * range. not all bits of the first and last words may be contained
3185 * within the block range. if this is the case, we'll work against
3186 * those words (i.e. partial first and/or last) on an individual basis
3187 * (a single pass), allocating the bits of interest by hand and
3188 * updating the leaf corresponding to the dmap word. a single pass
3189 * will be used for all dmap words fully contained within the
3190 * specified range. within this pass, the bits of all fully contained
3191 * dmap words will be marked as free in a single shot and the leaves
3192 * will be updated. a single leaf may describe the free space of
3193 * multiple dmap words, so we may update only a subset of the actual
3194 * leaves corresponding to the dmap words of the block range.
3195 */
3196 for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
3197 /* determine the bit number within the word and
3198 * the number of bits within the word.
3199 */
3200 wbitno = dbitno & (DBWORD - 1);
3201 nb = min(rembits, DBWORD - wbitno);
3202
3203 /* check if only part of a word is to be allocated.
3204 */
3205 if (nb < DBWORD) {
3206 /* allocate (set to 1) the appropriate bits within
3207 * this dmap word.
3208 */
3209 dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
3210 >> wbitno);
3211
3212 word++;
3213 } else {
3214 /* one or more dmap words are fully contained
3215 * within the block range. determine how many
3216 * words and allocate (set to 1) the bits of these
3217 * words.
3218 */
3219 nwords = rembits >> L2DBWORD;
3220 memset(&dp->wmap[word], (int) ONES, nwords * 4);
3221
3222 /* determine how many bits */
3223 nb = nwords << L2DBWORD;
3224 word += nwords;
3225 }
3226 }
3227
3228 /* update the free count for this dmap */
3229 dp->nfree = cpu_to_le32(le32_to_cpu(dp->nfree) - nblocks);
3230
3231 /* reconstruct summary tree */
3232 dbInitDmapTree(dp);
3233
3234 BMAP_LOCK(bmp);
3235
3236 /* if this allocation group is completely free,
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003237 * update the highest active allocation group number
Linus Torvalds1da177e2005-04-16 15:20:36 -07003238 * if this allocation group is the new max.
3239 */
3240 agno = blkno >> bmp->db_agl2size;
3241 if (agno > bmp->db_maxag)
3242 bmp->db_maxag = agno;
3243
3244 /* update the free count for the allocation group and map */
3245 bmp->db_agfree[agno] -= nblocks;
3246 bmp->db_nfree -= nblocks;
3247
3248 BMAP_UNLOCK(bmp);
3249
3250 /* if the root has not changed, done. */
3251 if (tp->stree[ROOT] == oldroot)
3252 return (0);
3253
3254 /* root changed. bubble the change up to the dmap control pages.
3255 * if the adjustment of the upper level control pages fails,
3256 * backout the bit allocation (thus making everything consistent).
3257 */
3258 if ((rc = dbAdjCtl(bmp, blkno, tp->stree[ROOT], 1, 0)))
3259 dbFreeBits(bmp, dp, blkno, nblocks);
3260
3261 return (rc);
3262}
3263
3264
3265/*
3266 * NAME: dbExtendFS()
3267 *
3268 * FUNCTION: extend bmap from blkno for nblocks;
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003269 * dbExtendFS() updates bmap ready for dbAllocBottomUp();
Linus Torvalds1da177e2005-04-16 15:20:36 -07003270 *
3271 * L2
3272 * |
3273 * L1---------------------------------L1
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003274 * | |
3275 * L0---------L0---------L0 L0---------L0---------L0
3276 * | | | | | |
3277 * d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,.,dm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003278 * L2L1L0d0,...,dnL0d0,...,dnL0d0,...,dnL1L0d0,...,dnL0d0,...,dnL0d0,..dm
3279 *
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003280 * <---old---><----------------------------extend----------------------->
Linus Torvalds1da177e2005-04-16 15:20:36 -07003281 */
3282int dbExtendFS(struct inode *ipbmap, s64 blkno, s64 nblocks)
3283{
3284 struct jfs_sb_info *sbi = JFS_SBI(ipbmap->i_sb);
3285 int nbperpage = sbi->nbperpage;
Richard Knutsson4d817152006-09-30 23:27:14 -07003286 int i, i0 = true, j, j0 = true, k, n;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003287 s64 newsize;
3288 s64 p;
3289 struct metapage *mp, *l2mp, *l1mp = NULL, *l0mp = NULL;
3290 struct dmapctl *l2dcp, *l1dcp, *l0dcp;
3291 struct dmap *dp;
3292 s8 *l0leaf, *l1leaf, *l2leaf;
3293 struct bmap *bmp = sbi->bmap;
3294 int agno, l2agsize, oldl2agsize;
3295 s64 ag_rem;
3296
3297 newsize = blkno + nblocks;
3298
3299 jfs_info("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld",
3300 (long long) blkno, (long long) nblocks, (long long) newsize);
3301
3302 /*
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003303 * initialize bmap control page.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003304 *
3305 * all the data in bmap control page should exclude
3306 * the mkfs hidden dmap page.
3307 */
3308
3309 /* update mapsize */
3310 bmp->db_mapsize = newsize;
3311 bmp->db_maxlevel = BMAPSZTOLEV(bmp->db_mapsize);
3312
3313 /* compute new AG size */
3314 l2agsize = dbGetL2AGSize(newsize);
3315 oldl2agsize = bmp->db_agl2size;
3316
3317 bmp->db_agl2size = l2agsize;
3318 bmp->db_agsize = 1 << l2agsize;
3319
3320 /* compute new number of AG */
3321 agno = bmp->db_numag;
3322 bmp->db_numag = newsize >> l2agsize;
3323 bmp->db_numag += ((u32) newsize % (u32) bmp->db_agsize) ? 1 : 0;
3324
3325 /*
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003326 * reconfigure db_agfree[]
Linus Torvalds1da177e2005-04-16 15:20:36 -07003327 * from old AG configuration to new AG configuration;
3328 *
3329 * coalesce contiguous k (newAGSize/oldAGSize) AGs;
3330 * i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn;
3331 * note: new AG size = old AG size * (2**x).
3332 */
3333 if (l2agsize == oldl2agsize)
3334 goto extend;
3335 k = 1 << (l2agsize - oldl2agsize);
3336 ag_rem = bmp->db_agfree[0]; /* save agfree[0] */
3337 for (i = 0, n = 0; i < agno; n++) {
3338 bmp->db_agfree[n] = 0; /* init collection point */
3339
3340 /* coalesce cotiguous k AGs; */
3341 for (j = 0; j < k && i < agno; j++, i++) {
3342 /* merge AGi to AGn */
3343 bmp->db_agfree[n] += bmp->db_agfree[i];
3344 }
3345 }
3346 bmp->db_agfree[0] += ag_rem; /* restore agfree[0] */
3347
3348 for (; n < MAXAG; n++)
3349 bmp->db_agfree[n] = 0;
3350
3351 /*
3352 * update highest active ag number
3353 */
3354
3355 bmp->db_maxag = bmp->db_maxag / k;
3356
3357 /*
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003358 * extend bmap
Linus Torvalds1da177e2005-04-16 15:20:36 -07003359 *
3360 * update bit maps and corresponding level control pages;
3361 * global control page db_nfree, db_agfree[agno], db_maxfreebud;
3362 */
3363 extend:
3364 /* get L2 page */
3365 p = BMAPBLKNO + nbperpage; /* L2 page */
3366 l2mp = read_metapage(ipbmap, p, PSIZE, 0);
3367 if (!l2mp) {
3368 jfs_error(ipbmap->i_sb, "dbExtendFS: L2 page could not be read");
3369 return -EIO;
3370 }
3371 l2dcp = (struct dmapctl *) l2mp->data;
3372
3373 /* compute start L1 */
3374 k = blkno >> L2MAXL1SIZE;
3375 l2leaf = l2dcp->stree + CTLLEAFIND + k;
3376 p = BLKTOL1(blkno, sbi->l2nbperpage); /* L1 page */
3377
3378 /*
3379 * extend each L1 in L2
3380 */
3381 for (; k < LPERCTL; k++, p += nbperpage) {
3382 /* get L1 page */
3383 if (j0) {
3384 /* read in L1 page: (blkno & (MAXL1SIZE - 1)) */
3385 l1mp = read_metapage(ipbmap, p, PSIZE, 0);
3386 if (l1mp == NULL)
3387 goto errout;
3388 l1dcp = (struct dmapctl *) l1mp->data;
3389
3390 /* compute start L0 */
3391 j = (blkno & (MAXL1SIZE - 1)) >> L2MAXL0SIZE;
3392 l1leaf = l1dcp->stree + CTLLEAFIND + j;
3393 p = BLKTOL0(blkno, sbi->l2nbperpage);
Richard Knutsson4d817152006-09-30 23:27:14 -07003394 j0 = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003395 } else {
3396 /* assign/init L1 page */
3397 l1mp = get_metapage(ipbmap, p, PSIZE, 0);
3398 if (l1mp == NULL)
3399 goto errout;
3400
3401 l1dcp = (struct dmapctl *) l1mp->data;
3402
3403 /* compute start L0 */
3404 j = 0;
3405 l1leaf = l1dcp->stree + CTLLEAFIND;
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003406 p += nbperpage; /* 1st L0 of L1.k */
Linus Torvalds1da177e2005-04-16 15:20:36 -07003407 }
3408
3409 /*
3410 * extend each L0 in L1
3411 */
3412 for (; j < LPERCTL; j++) {
3413 /* get L0 page */
3414 if (i0) {
3415 /* read in L0 page: (blkno & (MAXL0SIZE - 1)) */
3416
3417 l0mp = read_metapage(ipbmap, p, PSIZE, 0);
3418 if (l0mp == NULL)
3419 goto errout;
3420 l0dcp = (struct dmapctl *) l0mp->data;
3421
3422 /* compute start dmap */
3423 i = (blkno & (MAXL0SIZE - 1)) >>
3424 L2BPERDMAP;
3425 l0leaf = l0dcp->stree + CTLLEAFIND + i;
3426 p = BLKTODMAP(blkno,
3427 sbi->l2nbperpage);
Richard Knutsson4d817152006-09-30 23:27:14 -07003428 i0 = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003429 } else {
3430 /* assign/init L0 page */
3431 l0mp = get_metapage(ipbmap, p, PSIZE, 0);
3432 if (l0mp == NULL)
3433 goto errout;
3434
3435 l0dcp = (struct dmapctl *) l0mp->data;
3436
3437 /* compute start dmap */
3438 i = 0;
3439 l0leaf = l0dcp->stree + CTLLEAFIND;
3440 p += nbperpage; /* 1st dmap of L0.j */
3441 }
3442
3443 /*
3444 * extend each dmap in L0
3445 */
3446 for (; i < LPERCTL; i++) {
3447 /*
3448 * reconstruct the dmap page, and
3449 * initialize corresponding parent L0 leaf
3450 */
3451 if ((n = blkno & (BPERDMAP - 1))) {
3452 /* read in dmap page: */
3453 mp = read_metapage(ipbmap, p,
3454 PSIZE, 0);
3455 if (mp == NULL)
3456 goto errout;
3457 n = min(nblocks, (s64)BPERDMAP - n);
3458 } else {
3459 /* assign/init dmap page */
3460 mp = read_metapage(ipbmap, p,
3461 PSIZE, 0);
3462 if (mp == NULL)
3463 goto errout;
3464
3465 n = min(nblocks, (s64)BPERDMAP);
3466 }
3467
3468 dp = (struct dmap *) mp->data;
3469 *l0leaf = dbInitDmap(dp, blkno, n);
3470
3471 bmp->db_nfree += n;
3472 agno = le64_to_cpu(dp->start) >> l2agsize;
3473 bmp->db_agfree[agno] += n;
3474
3475 write_metapage(mp);
3476
3477 l0leaf++;
3478 p += nbperpage;
3479
3480 blkno += n;
3481 nblocks -= n;
3482 if (nblocks == 0)
3483 break;
3484 } /* for each dmap in a L0 */
3485
3486 /*
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003487 * build current L0 page from its leaves, and
Linus Torvalds1da177e2005-04-16 15:20:36 -07003488 * initialize corresponding parent L1 leaf
3489 */
3490 *l1leaf = dbInitDmapCtl(l0dcp, 0, ++i);
3491 write_metapage(l0mp);
3492 l0mp = NULL;
3493
3494 if (nblocks)
3495 l1leaf++; /* continue for next L0 */
3496 else {
3497 /* more than 1 L0 ? */
3498 if (j > 0)
3499 break; /* build L1 page */
3500 else {
3501 /* summarize in global bmap page */
3502 bmp->db_maxfreebud = *l1leaf;
3503 release_metapage(l1mp);
3504 release_metapage(l2mp);
3505 goto finalize;
3506 }
3507 }
3508 } /* for each L0 in a L1 */
3509
3510 /*
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003511 * build current L1 page from its leaves, and
Linus Torvalds1da177e2005-04-16 15:20:36 -07003512 * initialize corresponding parent L2 leaf
3513 */
3514 *l2leaf = dbInitDmapCtl(l1dcp, 1, ++j);
3515 write_metapage(l1mp);
3516 l1mp = NULL;
3517
3518 if (nblocks)
3519 l2leaf++; /* continue for next L1 */
3520 else {
3521 /* more than 1 L1 ? */
3522 if (k > 0)
3523 break; /* build L2 page */
3524 else {
3525 /* summarize in global bmap page */
3526 bmp->db_maxfreebud = *l2leaf;
3527 release_metapage(l2mp);
3528 goto finalize;
3529 }
3530 }
3531 } /* for each L1 in a L2 */
3532
3533 jfs_error(ipbmap->i_sb,
3534 "dbExtendFS: function has not returned as expected");
3535errout:
3536 if (l0mp)
3537 release_metapage(l0mp);
3538 if (l1mp)
3539 release_metapage(l1mp);
3540 release_metapage(l2mp);
3541 return -EIO;
3542
3543 /*
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003544 * finalize bmap control page
Linus Torvalds1da177e2005-04-16 15:20:36 -07003545 */
3546finalize:
3547
3548 return 0;
3549}
3550
3551
3552/*
3553 * dbFinalizeBmap()
3554 */
3555void dbFinalizeBmap(struct inode *ipbmap)
3556{
3557 struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
3558 int actags, inactags, l2nl;
3559 s64 ag_rem, actfree, inactfree, avgfree;
3560 int i, n;
3561
3562 /*
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003563 * finalize bmap control page
Linus Torvalds1da177e2005-04-16 15:20:36 -07003564 */
3565//finalize:
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003566 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -07003567 * compute db_agpref: preferred ag to allocate from
3568 * (the leftmost ag with average free space in it);
3569 */
3570//agpref:
3571 /* get the number of active ags and inacitve ags */
3572 actags = bmp->db_maxag + 1;
3573 inactags = bmp->db_numag - actags;
3574 ag_rem = bmp->db_mapsize & (bmp->db_agsize - 1); /* ??? */
3575
3576 /* determine how many blocks are in the inactive allocation
3577 * groups. in doing this, we must account for the fact that
3578 * the rightmost group might be a partial group (i.e. file
3579 * system size is not a multiple of the group size).
3580 */
3581 inactfree = (inactags && ag_rem) ?
3582 ((inactags - 1) << bmp->db_agl2size) + ag_rem
3583 : inactags << bmp->db_agl2size;
3584
3585 /* determine how many free blocks are in the active
3586 * allocation groups plus the average number of free blocks
3587 * within the active ags.
3588 */
3589 actfree = bmp->db_nfree - inactfree;
3590 avgfree = (u32) actfree / (u32) actags;
3591
3592 /* if the preferred allocation group has not average free space.
3593 * re-establish the preferred group as the leftmost
3594 * group with average free space.
3595 */
3596 if (bmp->db_agfree[bmp->db_agpref] < avgfree) {
3597 for (bmp->db_agpref = 0; bmp->db_agpref < actags;
3598 bmp->db_agpref++) {
3599 if (bmp->db_agfree[bmp->db_agpref] >= avgfree)
3600 break;
3601 }
3602 if (bmp->db_agpref >= bmp->db_numag) {
3603 jfs_error(ipbmap->i_sb,
3604 "cannot find ag with average freespace");
3605 }
3606 }
3607
3608 /*
3609 * compute db_aglevel, db_agheigth, db_width, db_agstart:
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003610 * an ag is covered in aglevel dmapctl summary tree,
3611 * at agheight level height (from leaf) with agwidth number of nodes
3612 * each, which starts at agstart index node of the smmary tree node
Linus Torvalds1da177e2005-04-16 15:20:36 -07003613 * array;
3614 */
3615 bmp->db_aglevel = BMAPSZTOLEV(bmp->db_agsize);
3616 l2nl =
3617 bmp->db_agl2size - (L2BPERDMAP + bmp->db_aglevel * L2LPERCTL);
3618 bmp->db_agheigth = l2nl >> 1;
3619 bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheigth << 1));
3620 for (i = 5 - bmp->db_agheigth, bmp->db_agstart = 0, n = 1; i > 0;
3621 i--) {
3622 bmp->db_agstart += n;
3623 n <<= 2;
3624 }
3625
3626}
3627
3628
3629/*
3630 * NAME: dbInitDmap()/ujfs_idmap_page()
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003631 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07003632 * FUNCTION: initialize working/persistent bitmap of the dmap page
3633 * for the specified number of blocks:
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003634 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07003635 * at entry, the bitmaps had been initialized as free (ZEROS);
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003636 * The number of blocks will only account for the actually
3637 * existing blocks. Blocks which don't actually exist in
Linus Torvalds1da177e2005-04-16 15:20:36 -07003638 * the aggregate will be marked as allocated (ONES);
3639 *
3640 * PARAMETERS:
3641 * dp - pointer to page of map
3642 * nblocks - number of blocks this page
3643 *
3644 * RETURNS: NONE
3645 */
3646static int dbInitDmap(struct dmap * dp, s64 Blkno, int nblocks)
3647{
3648 int blkno, w, b, r, nw, nb, i;
3649
3650 /* starting block number within the dmap */
3651 blkno = Blkno & (BPERDMAP - 1);
3652
3653 if (blkno == 0) {
3654 dp->nblocks = dp->nfree = cpu_to_le32(nblocks);
3655 dp->start = cpu_to_le64(Blkno);
3656
3657 if (nblocks == BPERDMAP) {
3658 memset(&dp->wmap[0], 0, LPERDMAP * 4);
3659 memset(&dp->pmap[0], 0, LPERDMAP * 4);
3660 goto initTree;
3661 }
3662 } else {
3663 dp->nblocks =
3664 cpu_to_le32(le32_to_cpu(dp->nblocks) + nblocks);
3665 dp->nfree = cpu_to_le32(le32_to_cpu(dp->nfree) + nblocks);
3666 }
3667
3668 /* word number containing start block number */
3669 w = blkno >> L2DBWORD;
3670
3671 /*
3672 * free the bits corresponding to the block range (ZEROS):
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003673 * note: not all bits of the first and last words may be contained
Linus Torvalds1da177e2005-04-16 15:20:36 -07003674 * within the block range.
3675 */
3676 for (r = nblocks; r > 0; r -= nb, blkno += nb) {
3677 /* number of bits preceding range to be freed in the word */
3678 b = blkno & (DBWORD - 1);
3679 /* number of bits to free in the word */
3680 nb = min(r, DBWORD - b);
3681
3682 /* is partial word to be freed ? */
3683 if (nb < DBWORD) {
3684 /* free (set to 0) from the bitmap word */
3685 dp->wmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3686 >> b));
3687 dp->pmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3688 >> b));
3689
3690 /* skip the word freed */
3691 w++;
3692 } else {
3693 /* free (set to 0) contiguous bitmap words */
3694 nw = r >> L2DBWORD;
3695 memset(&dp->wmap[w], 0, nw * 4);
3696 memset(&dp->pmap[w], 0, nw * 4);
3697
3698 /* skip the words freed */
3699 nb = nw << L2DBWORD;
3700 w += nw;
3701 }
3702 }
3703
3704 /*
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003705 * mark bits following the range to be freed (non-existing
Linus Torvalds1da177e2005-04-16 15:20:36 -07003706 * blocks) as allocated (ONES)
3707 */
3708
3709 if (blkno == BPERDMAP)
3710 goto initTree;
3711
3712 /* the first word beyond the end of existing blocks */
3713 w = blkno >> L2DBWORD;
3714
3715 /* does nblocks fall on a 32-bit boundary ? */
3716 b = blkno & (DBWORD - 1);
3717 if (b) {
3718 /* mark a partial word allocated */
3719 dp->wmap[w] = dp->pmap[w] = cpu_to_le32(ONES >> b);
3720 w++;
3721 }
3722
3723 /* set the rest of the words in the page to allocated (ONES) */
3724 for (i = w; i < LPERDMAP; i++)
3725 dp->pmap[i] = dp->wmap[i] = cpu_to_le32(ONES);
3726
3727 /*
3728 * init tree
3729 */
3730 initTree:
3731 return (dbInitDmapTree(dp));
3732}
3733
3734
3735/*
3736 * NAME: dbInitDmapTree()/ujfs_complete_dmap()
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003737 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07003738 * FUNCTION: initialize summary tree of the specified dmap:
3739 *
3740 * at entry, bitmap of the dmap has been initialized;
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003741 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07003742 * PARAMETERS:
3743 * dp - dmap to complete
3744 * blkno - starting block number for this dmap
3745 * treemax - will be filled in with max free for this dmap
3746 *
3747 * RETURNS: max free string at the root of the tree
3748 */
3749static int dbInitDmapTree(struct dmap * dp)
3750{
3751 struct dmaptree *tp;
3752 s8 *cp;
3753 int i;
3754
3755 /* init fixed info of tree */
3756 tp = &dp->tree;
3757 tp->nleafs = cpu_to_le32(LPERDMAP);
3758 tp->l2nleafs = cpu_to_le32(L2LPERDMAP);
3759 tp->leafidx = cpu_to_le32(LEAFIND);
3760 tp->height = cpu_to_le32(4);
3761 tp->budmin = BUDMIN;
3762
3763 /* init each leaf from corresponding wmap word:
3764 * note: leaf is set to NOFREE(-1) if all blocks of corresponding
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003765 * bitmap word are allocated.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003766 */
3767 cp = tp->stree + le32_to_cpu(tp->leafidx);
3768 for (i = 0; i < LPERDMAP; i++)
3769 *cp++ = dbMaxBud((u8 *) & dp->wmap[i]);
3770
3771 /* build the dmap's binary buddy summary tree */
3772 return (dbInitTree(tp));
3773}
3774
3775
3776/*
3777 * NAME: dbInitTree()/ujfs_adjtree()
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003778 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07003779 * FUNCTION: initialize binary buddy summary tree of a dmap or dmapctl.
3780 *
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003781 * at entry, the leaves of the tree has been initialized
Linus Torvalds1da177e2005-04-16 15:20:36 -07003782 * from corresponding bitmap word or root of summary tree
3783 * of the child control page;
3784 * configure binary buddy system at the leaf level, then
3785 * bubble up the values of the leaf nodes up the tree.
3786 *
3787 * PARAMETERS:
3788 * cp - Pointer to the root of the tree
3789 * l2leaves- Number of leaf nodes as a power of 2
3790 * l2min - Number of blocks that can be covered by a leaf
3791 * as a power of 2
3792 *
3793 * RETURNS: max free string at the root of the tree
3794 */
3795static int dbInitTree(struct dmaptree * dtp)
3796{
3797 int l2max, l2free, bsize, nextb, i;
3798 int child, parent, nparent;
3799 s8 *tp, *cp, *cp1;
3800
3801 tp = dtp->stree;
3802
3803 /* Determine the maximum free string possible for the leaves */
3804 l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin;
3805
3806 /*
3807 * configure the leaf levevl into binary buddy system
3808 *
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003809 * Try to combine buddies starting with a buddy size of 1
3810 * (i.e. two leaves). At a buddy size of 1 two buddy leaves
3811 * can be combined if both buddies have a maximum free of l2min;
3812 * the combination will result in the left-most buddy leaf having
3813 * a maximum free of l2min+1.
3814 * After processing all buddies for a given size, process buddies
3815 * at the next higher buddy size (i.e. current size * 2) and
3816 * the next maximum free (current free + 1).
3817 * This continues until the maximum possible buddy combination
Linus Torvalds1da177e2005-04-16 15:20:36 -07003818 * yields maximum free.
3819 */
3820 for (l2free = dtp->budmin, bsize = 1; l2free < l2max;
3821 l2free++, bsize = nextb) {
3822 /* get next buddy size == current buddy pair size */
3823 nextb = bsize << 1;
3824
3825 /* scan each adjacent buddy pair at current buddy size */
3826 for (i = 0, cp = tp + le32_to_cpu(dtp->leafidx);
3827 i < le32_to_cpu(dtp->nleafs);
3828 i += nextb, cp += nextb) {
3829 /* coalesce if both adjacent buddies are max free */
3830 if (*cp == l2free && *(cp + bsize) == l2free) {
3831 *cp = l2free + 1; /* left take right */
3832 *(cp + bsize) = -1; /* right give left */
3833 }
3834 }
3835 }
3836
3837 /*
3838 * bubble summary information of leaves up the tree.
3839 *
3840 * Starting at the leaf node level, the four nodes described by
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003841 * the higher level parent node are compared for a maximum free and
3842 * this maximum becomes the value of the parent node.
3843 * when all lower level nodes are processed in this fashion then
3844 * move up to the next level (parent becomes a lower level node) and
Linus Torvalds1da177e2005-04-16 15:20:36 -07003845 * continue the process for that level.
3846 */
3847 for (child = le32_to_cpu(dtp->leafidx),
3848 nparent = le32_to_cpu(dtp->nleafs) >> 2;
3849 nparent > 0; nparent >>= 2, child = parent) {
3850 /* get index of 1st node of parent level */
3851 parent = (child - 1) >> 2;
3852
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003853 /* set the value of the parent node as the maximum
Linus Torvalds1da177e2005-04-16 15:20:36 -07003854 * of the four nodes of the current level.
3855 */
3856 for (i = 0, cp = tp + child, cp1 = tp + parent;
3857 i < nparent; i++, cp += 4, cp1++)
3858 *cp1 = TREEMAX(cp);
3859 }
3860
3861 return (*tp);
3862}
3863
3864
3865/*
3866 * dbInitDmapCtl()
3867 *
3868 * function: initialize dmapctl page
3869 */
3870static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i)
3871{ /* start leaf index not covered by range */
3872 s8 *cp;
3873
3874 dcp->nleafs = cpu_to_le32(LPERCTL);
3875 dcp->l2nleafs = cpu_to_le32(L2LPERCTL);
3876 dcp->leafidx = cpu_to_le32(CTLLEAFIND);
3877 dcp->height = cpu_to_le32(5);
3878 dcp->budmin = L2BPERDMAP + L2LPERCTL * level;
3879
3880 /*
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003881 * initialize the leaves of current level that were not covered
3882 * by the specified input block range (i.e. the leaves have no
Linus Torvalds1da177e2005-04-16 15:20:36 -07003883 * low level dmapctl or dmap).
3884 */
3885 cp = &dcp->stree[CTLLEAFIND + i];
3886 for (; i < LPERCTL; i++)
3887 *cp++ = NOFREE;
3888
3889 /* build the dmap's binary buddy summary tree */
3890 return (dbInitTree((struct dmaptree *) dcp));
3891}
3892
3893
3894/*
3895 * NAME: dbGetL2AGSize()/ujfs_getagl2size()
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003896 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07003897 * FUNCTION: Determine log2(allocation group size) from aggregate size
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003898 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07003899 * PARAMETERS:
3900 * nblocks - Number of blocks in aggregate
3901 *
3902 * RETURNS: log2(allocation group size) in aggregate blocks
3903 */
3904static int dbGetL2AGSize(s64 nblocks)
3905{
3906 s64 sz;
3907 s64 m;
3908 int l2sz;
3909
3910 if (nblocks < BPERDMAP * MAXAG)
3911 return (L2BPERDMAP);
3912
3913 /* round up aggregate size to power of 2 */
3914 m = ((u64) 1 << (64 - 1));
3915 for (l2sz = 64; l2sz >= 0; l2sz--, m >>= 1) {
3916 if (m & nblocks)
3917 break;
3918 }
3919
3920 sz = (s64) 1 << l2sz;
3921 if (sz < nblocks)
3922 l2sz += 1;
3923
3924 /* agsize = roundupSize/max_number_of_ag */
3925 return (l2sz - L2MAXAG);
3926}
3927
3928
3929/*
3930 * NAME: dbMapFileSizeToMapSize()
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003931 *
3932 * FUNCTION: compute number of blocks the block allocation map file
Linus Torvalds1da177e2005-04-16 15:20:36 -07003933 * can cover from the map file size;
3934 *
3935 * RETURNS: Number of blocks which can be covered by this block map file;
3936 */
3937
3938/*
3939 * maximum number of map pages at each level including control pages
3940 */
3941#define MAXL0PAGES (1 + LPERCTL)
3942#define MAXL1PAGES (1 + LPERCTL * MAXL0PAGES)
3943#define MAXL2PAGES (1 + LPERCTL * MAXL1PAGES)
3944
3945/*
3946 * convert number of map pages to the zero origin top dmapctl level
3947 */
3948#define BMAPPGTOLEV(npages) \
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003949 (((npages) <= 3 + MAXL0PAGES) ? 0 : \
3950 ((npages) <= 2 + MAXL1PAGES) ? 1 : 2)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003951
3952s64 dbMapFileSizeToMapSize(struct inode * ipbmap)
3953{
3954 struct super_block *sb = ipbmap->i_sb;
3955 s64 nblocks;
3956 s64 npages, ndmaps;
3957 int level, i;
3958 int complete, factor;
3959
3960 nblocks = ipbmap->i_size >> JFS_SBI(sb)->l2bsize;
3961 npages = nblocks >> JFS_SBI(sb)->l2nbperpage;
3962 level = BMAPPGTOLEV(npages);
3963
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003964 /* At each level, accumulate the number of dmap pages covered by
Linus Torvalds1da177e2005-04-16 15:20:36 -07003965 * the number of full child levels below it;
3966 * repeat for the last incomplete child level.
3967 */
3968 ndmaps = 0;
3969 npages--; /* skip the first global control page */
3970 /* skip higher level control pages above top level covered by map */
3971 npages -= (2 - level);
3972 npages--; /* skip top level's control page */
3973 for (i = level; i >= 0; i--) {
3974 factor =
3975 (i == 2) ? MAXL1PAGES : ((i == 1) ? MAXL0PAGES : 1);
3976 complete = (u32) npages / factor;
Dave Kleikampf720e3b2007-06-06 15:28:35 -05003977 ndmaps += complete * ((i == 2) ? LPERCTL * LPERCTL :
3978 ((i == 1) ? LPERCTL : 1));
Linus Torvalds1da177e2005-04-16 15:20:36 -07003979
3980 /* pages in last/incomplete child */
3981 npages = (u32) npages % factor;
3982 /* skip incomplete child's level control page */
3983 npages--;
3984 }
3985
Dave Kleikamp63f83c92006-10-02 09:55:27 -05003986 /* convert the number of dmaps into the number of blocks
Linus Torvalds1da177e2005-04-16 15:20:36 -07003987 * which can be covered by the dmaps;
3988 */
3989 nblocks = ndmaps << L2BPERDMAP;
3990
3991 return (nblocks);
3992}