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1/*
2 * alloc.c - NILFS dat/inode allocator
3 *
4 * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * Originally written by Koji Sato.
17 * Two allocators were unified by Ryusuke Konishi and Amagai Yoshiji.
18 */
19
20#include <linux/types.h>
21#include <linux/buffer_head.h>
22#include <linux/fs.h>
23#include <linux/bitops.h>
24#include <linux/slab.h>
25#include "mdt.h"
26#include "alloc.h"
27
28
29/**
30 * nilfs_palloc_groups_per_desc_block - get the number of groups that a group
31 * descriptor block can maintain
32 * @inode: inode of metadata file using this allocator
33 */
34static inline unsigned long
35nilfs_palloc_groups_per_desc_block(const struct inode *inode)
36{
37 return i_blocksize(inode) /
38 sizeof(struct nilfs_palloc_group_desc);
39}
40
41/**
42 * nilfs_palloc_groups_count - get maximum number of groups
43 * @inode: inode of metadata file using this allocator
44 */
45static inline unsigned long
46nilfs_palloc_groups_count(const struct inode *inode)
47{
48 return 1UL << (BITS_PER_LONG - (inode->i_blkbits + 3 /* log2(8) */));
49}
50
51/**
52 * nilfs_palloc_init_blockgroup - initialize private variables for allocator
53 * @inode: inode of metadata file using this allocator
54 * @entry_size: size of the persistent object
55 */
56int nilfs_palloc_init_blockgroup(struct inode *inode, unsigned int entry_size)
57{
58 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
59
60 mi->mi_bgl = kmalloc(sizeof(*mi->mi_bgl), GFP_NOFS);
61 if (!mi->mi_bgl)
62 return -ENOMEM;
63
64 bgl_lock_init(mi->mi_bgl);
65
66 nilfs_mdt_set_entry_size(inode, entry_size, 0);
67
68 mi->mi_blocks_per_group =
69 DIV_ROUND_UP(nilfs_palloc_entries_per_group(inode),
70 mi->mi_entries_per_block) + 1;
71 /*
72 * Number of blocks in a group including entry blocks
73 * and a bitmap block
74 */
75 mi->mi_blocks_per_desc_block =
76 nilfs_palloc_groups_per_desc_block(inode) *
77 mi->mi_blocks_per_group + 1;
78 /*
79 * Number of blocks per descriptor including the
80 * descriptor block
81 */
82 return 0;
83}
84
85/**
86 * nilfs_palloc_group - get group number and offset from an entry number
87 * @inode: inode of metadata file using this allocator
88 * @nr: serial number of the entry (e.g. inode number)
89 * @offset: pointer to store offset number in the group
90 */
91static unsigned long nilfs_palloc_group(const struct inode *inode, __u64 nr,
92 unsigned long *offset)
93{
94 __u64 group = nr;
95
96 *offset = do_div(group, nilfs_palloc_entries_per_group(inode));
97 return group;
98}
99
100/**
101 * nilfs_palloc_desc_blkoff - get block offset of a group descriptor block
102 * @inode: inode of metadata file using this allocator
103 * @group: group number
104 *
105 * nilfs_palloc_desc_blkoff() returns block offset of the descriptor
106 * block which contains a descriptor of the specified group.
107 */
108static unsigned long
109nilfs_palloc_desc_blkoff(const struct inode *inode, unsigned long group)
110{
111 unsigned long desc_block =
112 group / nilfs_palloc_groups_per_desc_block(inode);
113 return desc_block * NILFS_MDT(inode)->mi_blocks_per_desc_block;
114}
115
116/**
117 * nilfs_palloc_bitmap_blkoff - get block offset of a bitmap block
118 * @inode: inode of metadata file using this allocator
119 * @group: group number
120 *
121 * nilfs_palloc_bitmap_blkoff() returns block offset of the bitmap
122 * block used to allocate/deallocate entries in the specified group.
123 */
124static unsigned long
125nilfs_palloc_bitmap_blkoff(const struct inode *inode, unsigned long group)
126{
127 unsigned long desc_offset =
128 group % nilfs_palloc_groups_per_desc_block(inode);
129 return nilfs_palloc_desc_blkoff(inode, group) + 1 +
130 desc_offset * NILFS_MDT(inode)->mi_blocks_per_group;
131}
132
133/**
134 * nilfs_palloc_group_desc_nfrees - get the number of free entries in a group
135 * @desc: pointer to descriptor structure for the group
136 * @lock: spin lock protecting @desc
137 */
138static unsigned long
139nilfs_palloc_group_desc_nfrees(const struct nilfs_palloc_group_desc *desc,
140 spinlock_t *lock)
141{
142 unsigned long nfree;
143
144 spin_lock(lock);
145 nfree = le32_to_cpu(desc->pg_nfrees);
146 spin_unlock(lock);
147 return nfree;
148}
149
150/**
151 * nilfs_palloc_group_desc_add_entries - adjust count of free entries
152 * @desc: pointer to descriptor structure for the group
153 * @lock: spin lock protecting @desc
154 * @n: delta to be added
155 */
156static u32
157nilfs_palloc_group_desc_add_entries(struct nilfs_palloc_group_desc *desc,
158 spinlock_t *lock, u32 n)
159{
160 u32 nfree;
161
162 spin_lock(lock);
163 le32_add_cpu(&desc->pg_nfrees, n);
164 nfree = le32_to_cpu(desc->pg_nfrees);
165 spin_unlock(lock);
166 return nfree;
167}
168
169/**
170 * nilfs_palloc_entry_blkoff - get block offset of an entry block
171 * @inode: inode of metadata file using this allocator
172 * @nr: serial number of the entry (e.g. inode number)
173 */
174static unsigned long
175nilfs_palloc_entry_blkoff(const struct inode *inode, __u64 nr)
176{
177 unsigned long group, group_offset;
178
179 group = nilfs_palloc_group(inode, nr, &group_offset);
180
181 return nilfs_palloc_bitmap_blkoff(inode, group) + 1 +
182 group_offset / NILFS_MDT(inode)->mi_entries_per_block;
183}
184
185/**
186 * nilfs_palloc_desc_block_init - initialize buffer of a group descriptor block
187 * @inode: inode of metadata file
188 * @bh: buffer head of the buffer to be initialized
189 * @kaddr: kernel address mapped for the page including the buffer
190 */
191static void nilfs_palloc_desc_block_init(struct inode *inode,
192 struct buffer_head *bh, void *kaddr)
193{
194 struct nilfs_palloc_group_desc *desc = kaddr + bh_offset(bh);
195 unsigned long n = nilfs_palloc_groups_per_desc_block(inode);
196 __le32 nfrees;
197
198 nfrees = cpu_to_le32(nilfs_palloc_entries_per_group(inode));
199 while (n-- > 0) {
200 desc->pg_nfrees = nfrees;
201 desc++;
202 }
203}
204
205static int nilfs_palloc_get_block(struct inode *inode, unsigned long blkoff,
206 int create,
207 void (*init_block)(struct inode *,
208 struct buffer_head *,
209 void *),
210 struct buffer_head **bhp,
211 struct nilfs_bh_assoc *prev,
212 spinlock_t *lock)
213{
214 int ret;
215
216 spin_lock(lock);
217 if (prev->bh && blkoff == prev->blkoff) {
218 get_bh(prev->bh);
219 *bhp = prev->bh;
220 spin_unlock(lock);
221 return 0;
222 }
223 spin_unlock(lock);
224
225 ret = nilfs_mdt_get_block(inode, blkoff, create, init_block, bhp);
226 if (!ret) {
227 spin_lock(lock);
228 /*
229 * The following code must be safe for change of the
230 * cache contents during the get block call.
231 */
232 brelse(prev->bh);
233 get_bh(*bhp);
234 prev->bh = *bhp;
235 prev->blkoff = blkoff;
236 spin_unlock(lock);
237 }
238 return ret;
239}
240
241/**
242 * nilfs_palloc_delete_block - delete a block on the persistent allocator file
243 * @inode: inode of metadata file using this allocator
244 * @blkoff: block offset
245 * @prev: nilfs_bh_assoc struct of the last used buffer
246 * @lock: spin lock protecting @prev
247 */
248static int nilfs_palloc_delete_block(struct inode *inode, unsigned long blkoff,
249 struct nilfs_bh_assoc *prev,
250 spinlock_t *lock)
251{
252 spin_lock(lock);
253 if (prev->bh && blkoff == prev->blkoff) {
254 brelse(prev->bh);
255 prev->bh = NULL;
256 }
257 spin_unlock(lock);
258 return nilfs_mdt_delete_block(inode, blkoff);
259}
260
261/**
262 * nilfs_palloc_get_desc_block - get buffer head of a group descriptor block
263 * @inode: inode of metadata file using this allocator
264 * @group: group number
265 * @create: create flag
266 * @bhp: pointer to store the resultant buffer head
267 */
268static int nilfs_palloc_get_desc_block(struct inode *inode,
269 unsigned long group,
270 int create, struct buffer_head **bhp)
271{
272 struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
273
274 return nilfs_palloc_get_block(inode,
275 nilfs_palloc_desc_blkoff(inode, group),
276 create, nilfs_palloc_desc_block_init,
277 bhp, &cache->prev_desc, &cache->lock);
278}
279
280/**
281 * nilfs_palloc_get_bitmap_block - get buffer head of a bitmap block
282 * @inode: inode of metadata file using this allocator
283 * @group: group number
284 * @create: create flag
285 * @bhp: pointer to store the resultant buffer head
286 */
287static int nilfs_palloc_get_bitmap_block(struct inode *inode,
288 unsigned long group,
289 int create, struct buffer_head **bhp)
290{
291 struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
292
293 return nilfs_palloc_get_block(inode,
294 nilfs_palloc_bitmap_blkoff(inode, group),
295 create, NULL, bhp,
296 &cache->prev_bitmap, &cache->lock);
297}
298
299/**
300 * nilfs_palloc_delete_bitmap_block - delete a bitmap block
301 * @inode: inode of metadata file using this allocator
302 * @group: group number
303 */
304static int nilfs_palloc_delete_bitmap_block(struct inode *inode,
305 unsigned long group)
306{
307 struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
308
309 return nilfs_palloc_delete_block(inode,
310 nilfs_palloc_bitmap_blkoff(inode,
311 group),
312 &cache->prev_bitmap, &cache->lock);
313}
314
315/**
316 * nilfs_palloc_get_entry_block - get buffer head of an entry block
317 * @inode: inode of metadata file using this allocator
318 * @nr: serial number of the entry (e.g. inode number)
319 * @create: create flag
320 * @bhp: pointer to store the resultant buffer head
321 */
322int nilfs_palloc_get_entry_block(struct inode *inode, __u64 nr,
323 int create, struct buffer_head **bhp)
324{
325 struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
326
327 return nilfs_palloc_get_block(inode,
328 nilfs_palloc_entry_blkoff(inode, nr),
329 create, NULL, bhp,
330 &cache->prev_entry, &cache->lock);
331}
332
333/**
334 * nilfs_palloc_delete_entry_block - delete an entry block
335 * @inode: inode of metadata file using this allocator
336 * @nr: serial number of the entry
337 */
338static int nilfs_palloc_delete_entry_block(struct inode *inode, __u64 nr)
339{
340 struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
341
342 return nilfs_palloc_delete_block(inode,
343 nilfs_palloc_entry_blkoff(inode, nr),
344 &cache->prev_entry, &cache->lock);
345}
346
347/**
348 * nilfs_palloc_block_get_group_desc - get kernel address of a group descriptor
349 * @inode: inode of metadata file using this allocator
350 * @group: group number
351 * @bh: buffer head of the buffer storing the group descriptor block
352 * @kaddr: kernel address mapped for the page including the buffer
353 */
354static struct nilfs_palloc_group_desc *
355nilfs_palloc_block_get_group_desc(const struct inode *inode,
356 unsigned long group,
357 const struct buffer_head *bh, void *kaddr)
358{
359 return (struct nilfs_palloc_group_desc *)(kaddr + bh_offset(bh)) +
360 group % nilfs_palloc_groups_per_desc_block(inode);
361}
362
363/**
364 * nilfs_palloc_block_get_entry - get kernel address of an entry
365 * @inode: inode of metadata file using this allocator
366 * @nr: serial number of the entry (e.g. inode number)
367 * @bh: buffer head of the buffer storing the entry block
368 * @kaddr: kernel address mapped for the page including the buffer
369 */
370void *nilfs_palloc_block_get_entry(const struct inode *inode, __u64 nr,
371 const struct buffer_head *bh, void *kaddr)
372{
373 unsigned long entry_offset, group_offset;
374
375 nilfs_palloc_group(inode, nr, &group_offset);
376 entry_offset = group_offset % NILFS_MDT(inode)->mi_entries_per_block;
377
378 return kaddr + bh_offset(bh) +
379 entry_offset * NILFS_MDT(inode)->mi_entry_size;
380}
381
382/**
383 * nilfs_palloc_find_available_slot - find available slot in a group
384 * @bitmap: bitmap of the group
385 * @target: offset number of an entry in the group (start point)
386 * @bsize: size in bits
387 * @lock: spin lock protecting @bitmap
388 */
389static int nilfs_palloc_find_available_slot(unsigned char *bitmap,
390 unsigned long target,
391 unsigned int bsize,
392 spinlock_t *lock)
393{
394 int pos, end = bsize;
395
396 if (likely(target < bsize)) {
397 pos = target;
398 do {
399 pos = nilfs_find_next_zero_bit(bitmap, end, pos);
400 if (pos >= end)
401 break;
402 if (!nilfs_set_bit_atomic(lock, pos, bitmap))
403 return pos;
404 } while (++pos < end);
405
406 end = target;
407 }
408
409 /* wrap around */
410 for (pos = 0; pos < end; pos++) {
411 pos = nilfs_find_next_zero_bit(bitmap, end, pos);
412 if (pos >= end)
413 break;
414 if (!nilfs_set_bit_atomic(lock, pos, bitmap))
415 return pos;
416 }
417
418 return -ENOSPC;
419}
420
421/**
422 * nilfs_palloc_rest_groups_in_desc_block - get the remaining number of groups
423 * in a group descriptor block
424 * @inode: inode of metadata file using this allocator
425 * @curr: current group number
426 * @max: maximum number of groups
427 */
428static unsigned long
429nilfs_palloc_rest_groups_in_desc_block(const struct inode *inode,
430 unsigned long curr, unsigned long max)
431{
432 return min_t(unsigned long,
433 nilfs_palloc_groups_per_desc_block(inode) -
434 curr % nilfs_palloc_groups_per_desc_block(inode),
435 max - curr + 1);
436}
437
438/**
439 * nilfs_palloc_count_desc_blocks - count descriptor blocks number
440 * @inode: inode of metadata file using this allocator
441 * @desc_blocks: descriptor blocks number [out]
442 */
443static int nilfs_palloc_count_desc_blocks(struct inode *inode,
444 unsigned long *desc_blocks)
445{
446 __u64 blknum;
447 int ret;
448
449 ret = nilfs_bmap_last_key(NILFS_I(inode)->i_bmap, &blknum);
450 if (likely(!ret))
451 *desc_blocks = DIV_ROUND_UP(
452 (unsigned long)blknum,
453 NILFS_MDT(inode)->mi_blocks_per_desc_block);
454 return ret;
455}
456
457/**
458 * nilfs_palloc_mdt_file_can_grow - check potential opportunity for
459 * MDT file growing
460 * @inode: inode of metadata file using this allocator
461 * @desc_blocks: known current descriptor blocks count
462 */
463static inline bool nilfs_palloc_mdt_file_can_grow(struct inode *inode,
464 unsigned long desc_blocks)
465{
466 return (nilfs_palloc_groups_per_desc_block(inode) * desc_blocks) <
467 nilfs_palloc_groups_count(inode);
468}
469
470/**
471 * nilfs_palloc_count_max_entries - count max number of entries that can be
472 * described by descriptor blocks count
473 * @inode: inode of metadata file using this allocator
474 * @nused: current number of used entries
475 * @nmaxp: max number of entries [out]
476 */
477int nilfs_palloc_count_max_entries(struct inode *inode, u64 nused, u64 *nmaxp)
478{
479 unsigned long desc_blocks = 0;
480 u64 entries_per_desc_block, nmax;
481 int err;
482
483 err = nilfs_palloc_count_desc_blocks(inode, &desc_blocks);
484 if (unlikely(err))
485 return err;
486
487 entries_per_desc_block = (u64)nilfs_palloc_entries_per_group(inode) *
488 nilfs_palloc_groups_per_desc_block(inode);
489 nmax = entries_per_desc_block * desc_blocks;
490
491 if (nused == nmax &&
492 nilfs_palloc_mdt_file_can_grow(inode, desc_blocks))
493 nmax += entries_per_desc_block;
494
495 if (nused > nmax)
496 return -ERANGE;
497
498 *nmaxp = nmax;
499 return 0;
500}
501
502/**
503 * nilfs_palloc_prepare_alloc_entry - prepare to allocate a persistent object
504 * @inode: inode of metadata file using this allocator
505 * @req: nilfs_palloc_req structure exchanged for the allocation
506 */
507int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
508 struct nilfs_palloc_req *req)
509{
510 struct buffer_head *desc_bh, *bitmap_bh;
511 struct nilfs_palloc_group_desc *desc;
512 unsigned char *bitmap;
513 void *desc_kaddr, *bitmap_kaddr;
514 unsigned long group, maxgroup, ngroups;
515 unsigned long group_offset, maxgroup_offset;
516 unsigned long n, entries_per_group;
517 unsigned long i, j;
518 spinlock_t *lock;
519 int pos, ret;
520
521 ngroups = nilfs_palloc_groups_count(inode);
522 maxgroup = ngroups - 1;
523 group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
524 entries_per_group = nilfs_palloc_entries_per_group(inode);
525
526 for (i = 0; i < ngroups; i += n) {
527 if (group >= ngroups) {
528 /* wrap around */
529 group = 0;
530 maxgroup = nilfs_palloc_group(inode, req->pr_entry_nr,
531 &maxgroup_offset) - 1;
532 }
533 ret = nilfs_palloc_get_desc_block(inode, group, 1, &desc_bh);
534 if (ret < 0)
535 return ret;
536 desc_kaddr = kmap(desc_bh->b_page);
537 desc = nilfs_palloc_block_get_group_desc(
538 inode, group, desc_bh, desc_kaddr);
539 n = nilfs_palloc_rest_groups_in_desc_block(inode, group,
540 maxgroup);
541 for (j = 0; j < n; j++, desc++, group++) {
542 lock = nilfs_mdt_bgl_lock(inode, group);
543 if (nilfs_palloc_group_desc_nfrees(desc, lock) > 0) {
544 ret = nilfs_palloc_get_bitmap_block(
545 inode, group, 1, &bitmap_bh);
546 if (ret < 0)
547 goto out_desc;
548 bitmap_kaddr = kmap(bitmap_bh->b_page);
549 bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
550 pos = nilfs_palloc_find_available_slot(
551 bitmap, group_offset,
552 entries_per_group, lock);
553 if (pos >= 0) {
554 /* found a free entry */
555 nilfs_palloc_group_desc_add_entries(
556 desc, lock, -1);
557 req->pr_entry_nr =
558 entries_per_group * group + pos;
559 kunmap(desc_bh->b_page);
560 kunmap(bitmap_bh->b_page);
561
562 req->pr_desc_bh = desc_bh;
563 req->pr_bitmap_bh = bitmap_bh;
564 return 0;
565 }
566 kunmap(bitmap_bh->b_page);
567 brelse(bitmap_bh);
568 }
569
570 group_offset = 0;
571 }
572
573 kunmap(desc_bh->b_page);
574 brelse(desc_bh);
575 }
576
577 /* no entries left */
578 return -ENOSPC;
579
580 out_desc:
581 kunmap(desc_bh->b_page);
582 brelse(desc_bh);
583 return ret;
584}
585
586/**
587 * nilfs_palloc_commit_alloc_entry - finish allocation of a persistent object
588 * @inode: inode of metadata file using this allocator
589 * @req: nilfs_palloc_req structure exchanged for the allocation
590 */
591void nilfs_palloc_commit_alloc_entry(struct inode *inode,
592 struct nilfs_palloc_req *req)
593{
594 mark_buffer_dirty(req->pr_bitmap_bh);
595 mark_buffer_dirty(req->pr_desc_bh);
596 nilfs_mdt_mark_dirty(inode);
597
598 brelse(req->pr_bitmap_bh);
599 brelse(req->pr_desc_bh);
600}
601
602/**
603 * nilfs_palloc_commit_free_entry - finish deallocating a persistent object
604 * @inode: inode of metadata file using this allocator
605 * @req: nilfs_palloc_req structure exchanged for the removal
606 */
607void nilfs_palloc_commit_free_entry(struct inode *inode,
608 struct nilfs_palloc_req *req)
609{
610 struct nilfs_palloc_group_desc *desc;
611 unsigned long group, group_offset;
612 unsigned char *bitmap;
613 void *desc_kaddr, *bitmap_kaddr;
614 spinlock_t *lock;
615
616 group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
617 desc_kaddr = kmap(req->pr_desc_bh->b_page);
618 desc = nilfs_palloc_block_get_group_desc(inode, group,
619 req->pr_desc_bh, desc_kaddr);
620 bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
621 bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
622 lock = nilfs_mdt_bgl_lock(inode, group);
623
624 if (!nilfs_clear_bit_atomic(lock, group_offset, bitmap))
625 nilfs_msg(inode->i_sb, KERN_WARNING,
626 "%s (ino=%lu): entry number %llu already freed",
627 __func__, inode->i_ino,
628 (unsigned long long)req->pr_entry_nr);
629 else
630 nilfs_palloc_group_desc_add_entries(desc, lock, 1);
631
632 kunmap(req->pr_bitmap_bh->b_page);
633 kunmap(req->pr_desc_bh->b_page);
634
635 mark_buffer_dirty(req->pr_desc_bh);
636 mark_buffer_dirty(req->pr_bitmap_bh);
637 nilfs_mdt_mark_dirty(inode);
638
639 brelse(req->pr_bitmap_bh);
640 brelse(req->pr_desc_bh);
641}
642
643/**
644 * nilfs_palloc_abort_alloc_entry - cancel allocation of a persistent object
645 * @inode: inode of metadata file using this allocator
646 * @req: nilfs_palloc_req structure exchanged for the allocation
647 */
648void nilfs_palloc_abort_alloc_entry(struct inode *inode,
649 struct nilfs_palloc_req *req)
650{
651 struct nilfs_palloc_group_desc *desc;
652 void *desc_kaddr, *bitmap_kaddr;
653 unsigned char *bitmap;
654 unsigned long group, group_offset;
655 spinlock_t *lock;
656
657 group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
658 desc_kaddr = kmap(req->pr_desc_bh->b_page);
659 desc = nilfs_palloc_block_get_group_desc(inode, group,
660 req->pr_desc_bh, desc_kaddr);
661 bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
662 bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
663 lock = nilfs_mdt_bgl_lock(inode, group);
664
665 if (!nilfs_clear_bit_atomic(lock, group_offset, bitmap))
666 nilfs_msg(inode->i_sb, KERN_WARNING,
667 "%s (ino=%lu): entry number %llu already freed",
668 __func__, inode->i_ino,
669 (unsigned long long)req->pr_entry_nr);
670 else
671 nilfs_palloc_group_desc_add_entries(desc, lock, 1);
672
673 kunmap(req->pr_bitmap_bh->b_page);
674 kunmap(req->pr_desc_bh->b_page);
675
676 brelse(req->pr_bitmap_bh);
677 brelse(req->pr_desc_bh);
678
679 req->pr_entry_nr = 0;
680 req->pr_bitmap_bh = NULL;
681 req->pr_desc_bh = NULL;
682}
683
684/**
685 * nilfs_palloc_prepare_free_entry - prepare to deallocate a persistent object
686 * @inode: inode of metadata file using this allocator
687 * @req: nilfs_palloc_req structure exchanged for the removal
688 */
689int nilfs_palloc_prepare_free_entry(struct inode *inode,
690 struct nilfs_palloc_req *req)
691{
692 struct buffer_head *desc_bh, *bitmap_bh;
693 unsigned long group, group_offset;
694 int ret;
695
696 group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
697 ret = nilfs_palloc_get_desc_block(inode, group, 1, &desc_bh);
698 if (ret < 0)
699 return ret;
700 ret = nilfs_palloc_get_bitmap_block(inode, group, 1, &bitmap_bh);
701 if (ret < 0) {
702 brelse(desc_bh);
703 return ret;
704 }
705
706 req->pr_desc_bh = desc_bh;
707 req->pr_bitmap_bh = bitmap_bh;
708 return 0;
709}
710
711/**
712 * nilfs_palloc_abort_free_entry - cancel deallocating a persistent object
713 * @inode: inode of metadata file using this allocator
714 * @req: nilfs_palloc_req structure exchanged for the removal
715 */
716void nilfs_palloc_abort_free_entry(struct inode *inode,
717 struct nilfs_palloc_req *req)
718{
719 brelse(req->pr_bitmap_bh);
720 brelse(req->pr_desc_bh);
721
722 req->pr_entry_nr = 0;
723 req->pr_bitmap_bh = NULL;
724 req->pr_desc_bh = NULL;
725}
726
727/**
728 * nilfs_palloc_freev - deallocate a set of persistent objects
729 * @inode: inode of metadata file using this allocator
730 * @entry_nrs: array of entry numbers to be deallocated
731 * @nitems: number of entries stored in @entry_nrs
732 */
733int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
734{
735 struct buffer_head *desc_bh, *bitmap_bh;
736 struct nilfs_palloc_group_desc *desc;
737 unsigned char *bitmap;
738 void *desc_kaddr, *bitmap_kaddr;
739 unsigned long group, group_offset;
740 __u64 group_min_nr, last_nrs[8];
741 const unsigned long epg = nilfs_palloc_entries_per_group(inode);
742 const unsigned int epb = NILFS_MDT(inode)->mi_entries_per_block;
743 unsigned int entry_start, end, pos;
744 spinlock_t *lock;
745 int i, j, k, ret;
746 u32 nfree;
747
748 for (i = 0; i < nitems; i = j) {
749 int change_group = false;
750 int nempties = 0, n = 0;
751
752 group = nilfs_palloc_group(inode, entry_nrs[i], &group_offset);
753 ret = nilfs_palloc_get_desc_block(inode, group, 0, &desc_bh);
754 if (ret < 0)
755 return ret;
756 ret = nilfs_palloc_get_bitmap_block(inode, group, 0,
757 &bitmap_bh);
758 if (ret < 0) {
759 brelse(desc_bh);
760 return ret;
761 }
762
763 /* Get the first entry number of the group */
764 group_min_nr = (__u64)group * epg;
765
766 bitmap_kaddr = kmap(bitmap_bh->b_page);
767 bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
768 lock = nilfs_mdt_bgl_lock(inode, group);
769
770 j = i;
771 entry_start = rounddown(group_offset, epb);
772 do {
773 if (!nilfs_clear_bit_atomic(lock, group_offset,
774 bitmap)) {
775 nilfs_msg(inode->i_sb, KERN_WARNING,
776 "%s (ino=%lu): entry number %llu already freed",
777 __func__, inode->i_ino,
778 (unsigned long long)entry_nrs[j]);
779 } else {
780 n++;
781 }
782
783 j++;
784 if (j >= nitems || entry_nrs[j] < group_min_nr ||
785 entry_nrs[j] >= group_min_nr + epg) {
786 change_group = true;
787 } else {
788 group_offset = entry_nrs[j] - group_min_nr;
789 if (group_offset >= entry_start &&
790 group_offset < entry_start + epb) {
791 /* This entry is in the same block */
792 continue;
793 }
794 }
795
796 /* Test if the entry block is empty or not */
797 end = entry_start + epb;
798 pos = nilfs_find_next_bit(bitmap, end, entry_start);
799 if (pos >= end) {
800 last_nrs[nempties++] = entry_nrs[j - 1];
801 if (nempties >= ARRAY_SIZE(last_nrs))
802 break;
803 }
804
805 if (change_group)
806 break;
807
808 /* Go on to the next entry block */
809 entry_start = rounddown(group_offset, epb);
810 } while (true);
811
812 kunmap(bitmap_bh->b_page);
813 mark_buffer_dirty(bitmap_bh);
814 brelse(bitmap_bh);
815
816 for (k = 0; k < nempties; k++) {
817 ret = nilfs_palloc_delete_entry_block(inode,
818 last_nrs[k]);
819 if (ret && ret != -ENOENT)
820 nilfs_msg(inode->i_sb, KERN_WARNING,
821 "error %d deleting block that object (entry=%llu, ino=%lu) belongs to",
822 ret, (unsigned long long)last_nrs[k],
823 inode->i_ino);
824 }
825
826 desc_kaddr = kmap_atomic(desc_bh->b_page);
827 desc = nilfs_palloc_block_get_group_desc(
828 inode, group, desc_bh, desc_kaddr);
829 nfree = nilfs_palloc_group_desc_add_entries(desc, lock, n);
830 kunmap_atomic(desc_kaddr);
831 mark_buffer_dirty(desc_bh);
832 nilfs_mdt_mark_dirty(inode);
833 brelse(desc_bh);
834
835 if (nfree == nilfs_palloc_entries_per_group(inode)) {
836 ret = nilfs_palloc_delete_bitmap_block(inode, group);
837 if (ret && ret != -ENOENT)
838 nilfs_msg(inode->i_sb, KERN_WARNING,
839 "error %d deleting bitmap block of group=%lu, ino=%lu",
840 ret, group, inode->i_ino);
841 }
842 }
843 return 0;
844}
845
846void nilfs_palloc_setup_cache(struct inode *inode,
847 struct nilfs_palloc_cache *cache)
848{
849 NILFS_MDT(inode)->mi_palloc_cache = cache;
850 spin_lock_init(&cache->lock);
851}
852
853void nilfs_palloc_clear_cache(struct inode *inode)
854{
855 struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
856
857 spin_lock(&cache->lock);
858 brelse(cache->prev_desc.bh);
859 brelse(cache->prev_bitmap.bh);
860 brelse(cache->prev_entry.bh);
861 cache->prev_desc.bh = NULL;
862 cache->prev_bitmap.bh = NULL;
863 cache->prev_entry.bh = NULL;
864 spin_unlock(&cache->lock);
865}
866
867void nilfs_palloc_destroy_cache(struct inode *inode)
868{
869 nilfs_palloc_clear_cache(inode);
870 NILFS_MDT(inode)->mi_palloc_cache = NULL;
871}
1/*
2 * alloc.c - NILFS dat/inode allocator
3 *
4 * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 *
20 * Original code was written by Koji Sato <koji@osrg.net>.
21 * Two allocators were unified by Ryusuke Konishi <ryusuke@osrg.net>,
22 * Amagai Yoshiji <amagai@osrg.net>.
23 */
24
25#include <linux/types.h>
26#include <linux/buffer_head.h>
27#include <linux/fs.h>
28#include <linux/bitops.h>
29#include <linux/slab.h>
30#include "mdt.h"
31#include "alloc.h"
32
33
34/**
35 * nilfs_palloc_groups_per_desc_block - get the number of groups that a group
36 * descriptor block can maintain
37 * @inode: inode of metadata file using this allocator
38 */
39static inline unsigned long
40nilfs_palloc_groups_per_desc_block(const struct inode *inode)
41{
42 return (1UL << inode->i_blkbits) /
43 sizeof(struct nilfs_palloc_group_desc);
44}
45
46/**
47 * nilfs_palloc_groups_count - get maximum number of groups
48 * @inode: inode of metadata file using this allocator
49 */
50static inline unsigned long
51nilfs_palloc_groups_count(const struct inode *inode)
52{
53 return 1UL << (BITS_PER_LONG - (inode->i_blkbits + 3 /* log2(8) */));
54}
55
56/**
57 * nilfs_palloc_init_blockgroup - initialize private variables for allocator
58 * @inode: inode of metadata file using this allocator
59 * @entry_size: size of the persistent object
60 */
61int nilfs_palloc_init_blockgroup(struct inode *inode, unsigned entry_size)
62{
63 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
64
65 mi->mi_bgl = kmalloc(sizeof(*mi->mi_bgl), GFP_NOFS);
66 if (!mi->mi_bgl)
67 return -ENOMEM;
68
69 bgl_lock_init(mi->mi_bgl);
70
71 nilfs_mdt_set_entry_size(inode, entry_size, 0);
72
73 mi->mi_blocks_per_group =
74 DIV_ROUND_UP(nilfs_palloc_entries_per_group(inode),
75 mi->mi_entries_per_block) + 1;
76 /* Number of blocks in a group including entry blocks and
77 a bitmap block */
78 mi->mi_blocks_per_desc_block =
79 nilfs_palloc_groups_per_desc_block(inode) *
80 mi->mi_blocks_per_group + 1;
81 /* Number of blocks per descriptor including the
82 descriptor block */
83 return 0;
84}
85
86/**
87 * nilfs_palloc_group - get group number and offset from an entry number
88 * @inode: inode of metadata file using this allocator
89 * @nr: serial number of the entry (e.g. inode number)
90 * @offset: pointer to store offset number in the group
91 */
92static unsigned long nilfs_palloc_group(const struct inode *inode, __u64 nr,
93 unsigned long *offset)
94{
95 __u64 group = nr;
96
97 *offset = do_div(group, nilfs_palloc_entries_per_group(inode));
98 return group;
99}
100
101/**
102 * nilfs_palloc_desc_blkoff - get block offset of a group descriptor block
103 * @inode: inode of metadata file using this allocator
104 * @group: group number
105 *
106 * nilfs_palloc_desc_blkoff() returns block offset of the descriptor
107 * block which contains a descriptor of the specified group.
108 */
109static unsigned long
110nilfs_palloc_desc_blkoff(const struct inode *inode, unsigned long group)
111{
112 unsigned long desc_block =
113 group / nilfs_palloc_groups_per_desc_block(inode);
114 return desc_block * NILFS_MDT(inode)->mi_blocks_per_desc_block;
115}
116
117/**
118 * nilfs_palloc_bitmap_blkoff - get block offset of a bitmap block
119 * @inode: inode of metadata file using this allocator
120 * @group: group number
121 *
122 * nilfs_palloc_bitmap_blkoff() returns block offset of the bitmap
123 * block used to allocate/deallocate entries in the specified group.
124 */
125static unsigned long
126nilfs_palloc_bitmap_blkoff(const struct inode *inode, unsigned long group)
127{
128 unsigned long desc_offset =
129 group % nilfs_palloc_groups_per_desc_block(inode);
130 return nilfs_palloc_desc_blkoff(inode, group) + 1 +
131 desc_offset * NILFS_MDT(inode)->mi_blocks_per_group;
132}
133
134/**
135 * nilfs_palloc_group_desc_nfrees - get the number of free entries in a group
136 * @inode: inode of metadata file using this allocator
137 * @group: group number
138 * @desc: pointer to descriptor structure for the group
139 */
140static unsigned long
141nilfs_palloc_group_desc_nfrees(struct inode *inode, unsigned long group,
142 const struct nilfs_palloc_group_desc *desc)
143{
144 unsigned long nfree;
145
146 spin_lock(nilfs_mdt_bgl_lock(inode, group));
147 nfree = le32_to_cpu(desc->pg_nfrees);
148 spin_unlock(nilfs_mdt_bgl_lock(inode, group));
149 return nfree;
150}
151
152/**
153 * nilfs_palloc_group_desc_add_entries - adjust count of free entries
154 * @inode: inode of metadata file using this allocator
155 * @group: group number
156 * @desc: pointer to descriptor structure for the group
157 * @n: delta to be added
158 */
159static void
160nilfs_palloc_group_desc_add_entries(struct inode *inode,
161 unsigned long group,
162 struct nilfs_palloc_group_desc *desc,
163 u32 n)
164{
165 spin_lock(nilfs_mdt_bgl_lock(inode, group));
166 le32_add_cpu(&desc->pg_nfrees, n);
167 spin_unlock(nilfs_mdt_bgl_lock(inode, group));
168}
169
170/**
171 * nilfs_palloc_entry_blkoff - get block offset of an entry block
172 * @inode: inode of metadata file using this allocator
173 * @nr: serial number of the entry (e.g. inode number)
174 */
175static unsigned long
176nilfs_palloc_entry_blkoff(const struct inode *inode, __u64 nr)
177{
178 unsigned long group, group_offset;
179
180 group = nilfs_palloc_group(inode, nr, &group_offset);
181
182 return nilfs_palloc_bitmap_blkoff(inode, group) + 1 +
183 group_offset / NILFS_MDT(inode)->mi_entries_per_block;
184}
185
186/**
187 * nilfs_palloc_desc_block_init - initialize buffer of a group descriptor block
188 * @inode: inode of metadata file
189 * @bh: buffer head of the buffer to be initialized
190 * @kaddr: kernel address mapped for the page including the buffer
191 */
192static void nilfs_palloc_desc_block_init(struct inode *inode,
193 struct buffer_head *bh, void *kaddr)
194{
195 struct nilfs_palloc_group_desc *desc = kaddr + bh_offset(bh);
196 unsigned long n = nilfs_palloc_groups_per_desc_block(inode);
197 __le32 nfrees;
198
199 nfrees = cpu_to_le32(nilfs_palloc_entries_per_group(inode));
200 while (n-- > 0) {
201 desc->pg_nfrees = nfrees;
202 desc++;
203 }
204}
205
206static int nilfs_palloc_get_block(struct inode *inode, unsigned long blkoff,
207 int create,
208 void (*init_block)(struct inode *,
209 struct buffer_head *,
210 void *),
211 struct buffer_head **bhp,
212 struct nilfs_bh_assoc *prev,
213 spinlock_t *lock)
214{
215 int ret;
216
217 spin_lock(lock);
218 if (prev->bh && blkoff == prev->blkoff) {
219 get_bh(prev->bh);
220 *bhp = prev->bh;
221 spin_unlock(lock);
222 return 0;
223 }
224 spin_unlock(lock);
225
226 ret = nilfs_mdt_get_block(inode, blkoff, create, init_block, bhp);
227 if (!ret) {
228 spin_lock(lock);
229 /*
230 * The following code must be safe for change of the
231 * cache contents during the get block call.
232 */
233 brelse(prev->bh);
234 get_bh(*bhp);
235 prev->bh = *bhp;
236 prev->blkoff = blkoff;
237 spin_unlock(lock);
238 }
239 return ret;
240}
241
242/**
243 * nilfs_palloc_get_desc_block - get buffer head of a group descriptor block
244 * @inode: inode of metadata file using this allocator
245 * @group: group number
246 * @create: create flag
247 * @bhp: pointer to store the resultant buffer head
248 */
249static int nilfs_palloc_get_desc_block(struct inode *inode,
250 unsigned long group,
251 int create, struct buffer_head **bhp)
252{
253 struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
254
255 return nilfs_palloc_get_block(inode,
256 nilfs_palloc_desc_blkoff(inode, group),
257 create, nilfs_palloc_desc_block_init,
258 bhp, &cache->prev_desc, &cache->lock);
259}
260
261/**
262 * nilfs_palloc_get_bitmap_block - get buffer head of a bitmap block
263 * @inode: inode of metadata file using this allocator
264 * @group: group number
265 * @create: create flag
266 * @bhp: pointer to store the resultant buffer head
267 */
268static int nilfs_palloc_get_bitmap_block(struct inode *inode,
269 unsigned long group,
270 int create, struct buffer_head **bhp)
271{
272 struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
273
274 return nilfs_palloc_get_block(inode,
275 nilfs_palloc_bitmap_blkoff(inode, group),
276 create, NULL, bhp,
277 &cache->prev_bitmap, &cache->lock);
278}
279
280/**
281 * nilfs_palloc_get_entry_block - get buffer head of an entry block
282 * @inode: inode of metadata file using this allocator
283 * @nr: serial number of the entry (e.g. inode number)
284 * @create: create flag
285 * @bhp: pointer to store the resultant buffer head
286 */
287int nilfs_palloc_get_entry_block(struct inode *inode, __u64 nr,
288 int create, struct buffer_head **bhp)
289{
290 struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
291
292 return nilfs_palloc_get_block(inode,
293 nilfs_palloc_entry_blkoff(inode, nr),
294 create, NULL, bhp,
295 &cache->prev_entry, &cache->lock);
296}
297
298/**
299 * nilfs_palloc_block_get_group_desc - get kernel address of a group descriptor
300 * @inode: inode of metadata file using this allocator
301 * @group: group number
302 * @bh: buffer head of the buffer storing the group descriptor block
303 * @kaddr: kernel address mapped for the page including the buffer
304 */
305static struct nilfs_palloc_group_desc *
306nilfs_palloc_block_get_group_desc(const struct inode *inode,
307 unsigned long group,
308 const struct buffer_head *bh, void *kaddr)
309{
310 return (struct nilfs_palloc_group_desc *)(kaddr + bh_offset(bh)) +
311 group % nilfs_palloc_groups_per_desc_block(inode);
312}
313
314/**
315 * nilfs_palloc_block_get_entry - get kernel address of an entry
316 * @inode: inode of metadata file using this allocator
317 * @nr: serial number of the entry (e.g. inode number)
318 * @bh: buffer head of the buffer storing the entry block
319 * @kaddr: kernel address mapped for the page including the buffer
320 */
321void *nilfs_palloc_block_get_entry(const struct inode *inode, __u64 nr,
322 const struct buffer_head *bh, void *kaddr)
323{
324 unsigned long entry_offset, group_offset;
325
326 nilfs_palloc_group(inode, nr, &group_offset);
327 entry_offset = group_offset % NILFS_MDT(inode)->mi_entries_per_block;
328
329 return kaddr + bh_offset(bh) +
330 entry_offset * NILFS_MDT(inode)->mi_entry_size;
331}
332
333/**
334 * nilfs_palloc_find_available_slot - find available slot in a group
335 * @inode: inode of metadata file using this allocator
336 * @group: group number
337 * @target: offset number of an entry in the group (start point)
338 * @bitmap: bitmap of the group
339 * @bsize: size in bits
340 */
341static int nilfs_palloc_find_available_slot(struct inode *inode,
342 unsigned long group,
343 unsigned long target,
344 unsigned char *bitmap,
345 int bsize)
346{
347 int curr, pos, end, i;
348
349 if (target > 0) {
350 end = (target + BITS_PER_LONG - 1) & ~(BITS_PER_LONG - 1);
351 if (end > bsize)
352 end = bsize;
353 pos = nilfs_find_next_zero_bit(bitmap, end, target);
354 if (pos < end &&
355 !nilfs_set_bit_atomic(
356 nilfs_mdt_bgl_lock(inode, group), pos, bitmap))
357 return pos;
358 } else
359 end = 0;
360
361 for (i = 0, curr = end;
362 i < bsize;
363 i += BITS_PER_LONG, curr += BITS_PER_LONG) {
364 /* wrap around */
365 if (curr >= bsize)
366 curr = 0;
367 while (*((unsigned long *)bitmap + curr / BITS_PER_LONG)
368 != ~0UL) {
369 end = curr + BITS_PER_LONG;
370 if (end > bsize)
371 end = bsize;
372 pos = nilfs_find_next_zero_bit(bitmap, end, curr);
373 if ((pos < end) &&
374 !nilfs_set_bit_atomic(
375 nilfs_mdt_bgl_lock(inode, group), pos,
376 bitmap))
377 return pos;
378 }
379 }
380 return -ENOSPC;
381}
382
383/**
384 * nilfs_palloc_rest_groups_in_desc_block - get the remaining number of groups
385 * in a group descriptor block
386 * @inode: inode of metadata file using this allocator
387 * @curr: current group number
388 * @max: maximum number of groups
389 */
390static unsigned long
391nilfs_palloc_rest_groups_in_desc_block(const struct inode *inode,
392 unsigned long curr, unsigned long max)
393{
394 return min_t(unsigned long,
395 nilfs_palloc_groups_per_desc_block(inode) -
396 curr % nilfs_palloc_groups_per_desc_block(inode),
397 max - curr + 1);
398}
399
400/**
401 * nilfs_palloc_count_desc_blocks - count descriptor blocks number
402 * @inode: inode of metadata file using this allocator
403 * @desc_blocks: descriptor blocks number [out]
404 */
405static int nilfs_palloc_count_desc_blocks(struct inode *inode,
406 unsigned long *desc_blocks)
407{
408 unsigned long blknum;
409 int ret;
410
411 ret = nilfs_bmap_last_key(NILFS_I(inode)->i_bmap, &blknum);
412 if (likely(!ret))
413 *desc_blocks = DIV_ROUND_UP(
414 blknum, NILFS_MDT(inode)->mi_blocks_per_desc_block);
415 return ret;
416}
417
418/**
419 * nilfs_palloc_mdt_file_can_grow - check potential opportunity for
420 * MDT file growing
421 * @inode: inode of metadata file using this allocator
422 * @desc_blocks: known current descriptor blocks count
423 */
424static inline bool nilfs_palloc_mdt_file_can_grow(struct inode *inode,
425 unsigned long desc_blocks)
426{
427 return (nilfs_palloc_groups_per_desc_block(inode) * desc_blocks) <
428 nilfs_palloc_groups_count(inode);
429}
430
431/**
432 * nilfs_palloc_count_max_entries - count max number of entries that can be
433 * described by descriptor blocks count
434 * @inode: inode of metadata file using this allocator
435 * @nused: current number of used entries
436 * @nmaxp: max number of entries [out]
437 */
438int nilfs_palloc_count_max_entries(struct inode *inode, u64 nused, u64 *nmaxp)
439{
440 unsigned long desc_blocks = 0;
441 u64 entries_per_desc_block, nmax;
442 int err;
443
444 err = nilfs_palloc_count_desc_blocks(inode, &desc_blocks);
445 if (unlikely(err))
446 return err;
447
448 entries_per_desc_block = (u64)nilfs_palloc_entries_per_group(inode) *
449 nilfs_palloc_groups_per_desc_block(inode);
450 nmax = entries_per_desc_block * desc_blocks;
451
452 if (nused == nmax &&
453 nilfs_palloc_mdt_file_can_grow(inode, desc_blocks))
454 nmax += entries_per_desc_block;
455
456 if (nused > nmax)
457 return -ERANGE;
458
459 *nmaxp = nmax;
460 return 0;
461}
462
463/**
464 * nilfs_palloc_prepare_alloc_entry - prepare to allocate a persistent object
465 * @inode: inode of metadata file using this allocator
466 * @req: nilfs_palloc_req structure exchanged for the allocation
467 */
468int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
469 struct nilfs_palloc_req *req)
470{
471 struct buffer_head *desc_bh, *bitmap_bh;
472 struct nilfs_palloc_group_desc *desc;
473 unsigned char *bitmap;
474 void *desc_kaddr, *bitmap_kaddr;
475 unsigned long group, maxgroup, ngroups;
476 unsigned long group_offset, maxgroup_offset;
477 unsigned long n, entries_per_group, groups_per_desc_block;
478 unsigned long i, j;
479 int pos, ret;
480
481 ngroups = nilfs_palloc_groups_count(inode);
482 maxgroup = ngroups - 1;
483 group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
484 entries_per_group = nilfs_palloc_entries_per_group(inode);
485 groups_per_desc_block = nilfs_palloc_groups_per_desc_block(inode);
486
487 for (i = 0; i < ngroups; i += n) {
488 if (group >= ngroups) {
489 /* wrap around */
490 group = 0;
491 maxgroup = nilfs_palloc_group(inode, req->pr_entry_nr,
492 &maxgroup_offset) - 1;
493 }
494 ret = nilfs_palloc_get_desc_block(inode, group, 1, &desc_bh);
495 if (ret < 0)
496 return ret;
497 desc_kaddr = kmap(desc_bh->b_page);
498 desc = nilfs_palloc_block_get_group_desc(
499 inode, group, desc_bh, desc_kaddr);
500 n = nilfs_palloc_rest_groups_in_desc_block(inode, group,
501 maxgroup);
502 for (j = 0; j < n; j++, desc++, group++) {
503 if (nilfs_palloc_group_desc_nfrees(inode, group, desc)
504 > 0) {
505 ret = nilfs_palloc_get_bitmap_block(
506 inode, group, 1, &bitmap_bh);
507 if (ret < 0)
508 goto out_desc;
509 bitmap_kaddr = kmap(bitmap_bh->b_page);
510 bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
511 pos = nilfs_palloc_find_available_slot(
512 inode, group, group_offset, bitmap,
513 entries_per_group);
514 if (pos >= 0) {
515 /* found a free entry */
516 nilfs_palloc_group_desc_add_entries(
517 inode, group, desc, -1);
518 req->pr_entry_nr =
519 entries_per_group * group + pos;
520 kunmap(desc_bh->b_page);
521 kunmap(bitmap_bh->b_page);
522
523 req->pr_desc_bh = desc_bh;
524 req->pr_bitmap_bh = bitmap_bh;
525 return 0;
526 }
527 kunmap(bitmap_bh->b_page);
528 brelse(bitmap_bh);
529 }
530
531 group_offset = 0;
532 }
533
534 kunmap(desc_bh->b_page);
535 brelse(desc_bh);
536 }
537
538 /* no entries left */
539 return -ENOSPC;
540
541 out_desc:
542 kunmap(desc_bh->b_page);
543 brelse(desc_bh);
544 return ret;
545}
546
547/**
548 * nilfs_palloc_commit_alloc_entry - finish allocation of a persistent object
549 * @inode: inode of metadata file using this allocator
550 * @req: nilfs_palloc_req structure exchanged for the allocation
551 */
552void nilfs_palloc_commit_alloc_entry(struct inode *inode,
553 struct nilfs_palloc_req *req)
554{
555 mark_buffer_dirty(req->pr_bitmap_bh);
556 mark_buffer_dirty(req->pr_desc_bh);
557 nilfs_mdt_mark_dirty(inode);
558
559 brelse(req->pr_bitmap_bh);
560 brelse(req->pr_desc_bh);
561}
562
563/**
564 * nilfs_palloc_commit_free_entry - finish deallocating a persistent object
565 * @inode: inode of metadata file using this allocator
566 * @req: nilfs_palloc_req structure exchanged for the removal
567 */
568void nilfs_palloc_commit_free_entry(struct inode *inode,
569 struct nilfs_palloc_req *req)
570{
571 struct nilfs_palloc_group_desc *desc;
572 unsigned long group, group_offset;
573 unsigned char *bitmap;
574 void *desc_kaddr, *bitmap_kaddr;
575
576 group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
577 desc_kaddr = kmap(req->pr_desc_bh->b_page);
578 desc = nilfs_palloc_block_get_group_desc(inode, group,
579 req->pr_desc_bh, desc_kaddr);
580 bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
581 bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
582
583 if (!nilfs_clear_bit_atomic(nilfs_mdt_bgl_lock(inode, group),
584 group_offset, bitmap))
585 printk(KERN_WARNING "%s: entry number %llu already freed\n",
586 __func__, (unsigned long long)req->pr_entry_nr);
587 else
588 nilfs_palloc_group_desc_add_entries(inode, group, desc, 1);
589
590 kunmap(req->pr_bitmap_bh->b_page);
591 kunmap(req->pr_desc_bh->b_page);
592
593 mark_buffer_dirty(req->pr_desc_bh);
594 mark_buffer_dirty(req->pr_bitmap_bh);
595 nilfs_mdt_mark_dirty(inode);
596
597 brelse(req->pr_bitmap_bh);
598 brelse(req->pr_desc_bh);
599}
600
601/**
602 * nilfs_palloc_abort_alloc_entry - cancel allocation of a persistent object
603 * @inode: inode of metadata file using this allocator
604 * @req: nilfs_palloc_req structure exchanged for the allocation
605 */
606void nilfs_palloc_abort_alloc_entry(struct inode *inode,
607 struct nilfs_palloc_req *req)
608{
609 struct nilfs_palloc_group_desc *desc;
610 void *desc_kaddr, *bitmap_kaddr;
611 unsigned char *bitmap;
612 unsigned long group, group_offset;
613
614 group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
615 desc_kaddr = kmap(req->pr_desc_bh->b_page);
616 desc = nilfs_palloc_block_get_group_desc(inode, group,
617 req->pr_desc_bh, desc_kaddr);
618 bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
619 bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
620 if (!nilfs_clear_bit_atomic(nilfs_mdt_bgl_lock(inode, group),
621 group_offset, bitmap))
622 printk(KERN_WARNING "%s: entry number %llu already freed\n",
623 __func__, (unsigned long long)req->pr_entry_nr);
624 else
625 nilfs_palloc_group_desc_add_entries(inode, group, desc, 1);
626
627 kunmap(req->pr_bitmap_bh->b_page);
628 kunmap(req->pr_desc_bh->b_page);
629
630 brelse(req->pr_bitmap_bh);
631 brelse(req->pr_desc_bh);
632
633 req->pr_entry_nr = 0;
634 req->pr_bitmap_bh = NULL;
635 req->pr_desc_bh = NULL;
636}
637
638/**
639 * nilfs_palloc_prepare_free_entry - prepare to deallocate a persistent object
640 * @inode: inode of metadata file using this allocator
641 * @req: nilfs_palloc_req structure exchanged for the removal
642 */
643int nilfs_palloc_prepare_free_entry(struct inode *inode,
644 struct nilfs_palloc_req *req)
645{
646 struct buffer_head *desc_bh, *bitmap_bh;
647 unsigned long group, group_offset;
648 int ret;
649
650 group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
651 ret = nilfs_palloc_get_desc_block(inode, group, 1, &desc_bh);
652 if (ret < 0)
653 return ret;
654 ret = nilfs_palloc_get_bitmap_block(inode, group, 1, &bitmap_bh);
655 if (ret < 0) {
656 brelse(desc_bh);
657 return ret;
658 }
659
660 req->pr_desc_bh = desc_bh;
661 req->pr_bitmap_bh = bitmap_bh;
662 return 0;
663}
664
665/**
666 * nilfs_palloc_abort_free_entry - cancel deallocating a persistent object
667 * @inode: inode of metadata file using this allocator
668 * @req: nilfs_palloc_req structure exchanged for the removal
669 */
670void nilfs_palloc_abort_free_entry(struct inode *inode,
671 struct nilfs_palloc_req *req)
672{
673 brelse(req->pr_bitmap_bh);
674 brelse(req->pr_desc_bh);
675
676 req->pr_entry_nr = 0;
677 req->pr_bitmap_bh = NULL;
678 req->pr_desc_bh = NULL;
679}
680
681/**
682 * nilfs_palloc_group_is_in - judge if an entry is in a group
683 * @inode: inode of metadata file using this allocator
684 * @group: group number
685 * @nr: serial number of the entry (e.g. inode number)
686 */
687static int
688nilfs_palloc_group_is_in(struct inode *inode, unsigned long group, __u64 nr)
689{
690 __u64 first, last;
691
692 first = group * nilfs_palloc_entries_per_group(inode);
693 last = first + nilfs_palloc_entries_per_group(inode) - 1;
694 return (nr >= first) && (nr <= last);
695}
696
697/**
698 * nilfs_palloc_freev - deallocate a set of persistent objects
699 * @inode: inode of metadata file using this allocator
700 * @entry_nrs: array of entry numbers to be deallocated
701 * @nitems: number of entries stored in @entry_nrs
702 */
703int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
704{
705 struct buffer_head *desc_bh, *bitmap_bh;
706 struct nilfs_palloc_group_desc *desc;
707 unsigned char *bitmap;
708 void *desc_kaddr, *bitmap_kaddr;
709 unsigned long group, group_offset;
710 int i, j, n, ret;
711
712 for (i = 0; i < nitems; i = j) {
713 group = nilfs_palloc_group(inode, entry_nrs[i], &group_offset);
714 ret = nilfs_palloc_get_desc_block(inode, group, 0, &desc_bh);
715 if (ret < 0)
716 return ret;
717 ret = nilfs_palloc_get_bitmap_block(inode, group, 0,
718 &bitmap_bh);
719 if (ret < 0) {
720 brelse(desc_bh);
721 return ret;
722 }
723 desc_kaddr = kmap(desc_bh->b_page);
724 desc = nilfs_palloc_block_get_group_desc(
725 inode, group, desc_bh, desc_kaddr);
726 bitmap_kaddr = kmap(bitmap_bh->b_page);
727 bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
728 for (j = i, n = 0;
729 (j < nitems) && nilfs_palloc_group_is_in(inode, group,
730 entry_nrs[j]);
731 j++) {
732 nilfs_palloc_group(inode, entry_nrs[j], &group_offset);
733 if (!nilfs_clear_bit_atomic(
734 nilfs_mdt_bgl_lock(inode, group),
735 group_offset, bitmap)) {
736 printk(KERN_WARNING
737 "%s: entry number %llu already freed\n",
738 __func__,
739 (unsigned long long)entry_nrs[j]);
740 } else {
741 n++;
742 }
743 }
744 nilfs_palloc_group_desc_add_entries(inode, group, desc, n);
745
746 kunmap(bitmap_bh->b_page);
747 kunmap(desc_bh->b_page);
748
749 mark_buffer_dirty(desc_bh);
750 mark_buffer_dirty(bitmap_bh);
751 nilfs_mdt_mark_dirty(inode);
752
753 brelse(bitmap_bh);
754 brelse(desc_bh);
755 }
756 return 0;
757}
758
759void nilfs_palloc_setup_cache(struct inode *inode,
760 struct nilfs_palloc_cache *cache)
761{
762 NILFS_MDT(inode)->mi_palloc_cache = cache;
763 spin_lock_init(&cache->lock);
764}
765
766void nilfs_palloc_clear_cache(struct inode *inode)
767{
768 struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
769
770 spin_lock(&cache->lock);
771 brelse(cache->prev_desc.bh);
772 brelse(cache->prev_bitmap.bh);
773 brelse(cache->prev_entry.bh);
774 cache->prev_desc.bh = NULL;
775 cache->prev_bitmap.bh = NULL;
776 cache->prev_entry.bh = NULL;
777 spin_unlock(&cache->lock);
778}
779
780void nilfs_palloc_destroy_cache(struct inode *inode)
781{
782 nilfs_palloc_clear_cache(inode);
783 NILFS_MDT(inode)->mi_palloc_cache = NULL;
784}