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1/*
2 * fs/logfs/segment.c - Handling the Object Store
3 *
4 * As should be obvious for Linux kernel code, license is GPLv2
5 *
6 * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
7 *
8 * Object store or ostore makes up the complete device with exception of
9 * the superblock and journal areas. Apart from its own metadata it stores
10 * three kinds of objects: inodes, dentries and blocks, both data and indirect.
11 */
12#include "logfs.h"
13#include <linux/slab.h>
14
15static int logfs_mark_segment_bad(struct super_block *sb, u32 segno)
16{
17 struct logfs_super *super = logfs_super(sb);
18 struct btree_head32 *head = &super->s_reserved_segments;
19 int err;
20
21 err = btree_insert32(head, segno, (void *)1, GFP_NOFS);
22 if (err)
23 return err;
24 logfs_super(sb)->s_bad_segments++;
25 /* FIXME: write to journal */
26 return 0;
27}
28
29int logfs_erase_segment(struct super_block *sb, u32 segno, int ensure_erase)
30{
31 struct logfs_super *super = logfs_super(sb);
32
33 super->s_gec++;
34
35 return super->s_devops->erase(sb, (u64)segno << super->s_segshift,
36 super->s_segsize, ensure_erase);
37}
38
39static s64 logfs_get_free_bytes(struct logfs_area *area, size_t bytes)
40{
41 s32 ofs;
42
43 logfs_open_area(area, bytes);
44
45 ofs = area->a_used_bytes;
46 area->a_used_bytes += bytes;
47 BUG_ON(area->a_used_bytes >= logfs_super(area->a_sb)->s_segsize);
48
49 return dev_ofs(area->a_sb, area->a_segno, ofs);
50}
51
52static struct page *get_mapping_page(struct super_block *sb, pgoff_t index,
53 int use_filler)
54{
55 struct logfs_super *super = logfs_super(sb);
56 struct address_space *mapping = super->s_mapping_inode->i_mapping;
57 filler_t *filler = super->s_devops->readpage;
58 struct page *page;
59
60 BUG_ON(mapping_gfp_mask(mapping) & __GFP_FS);
61 if (use_filler)
62 page = read_cache_page(mapping, index, filler, sb);
63 else {
64 page = find_or_create_page(mapping, index, GFP_NOFS);
65 unlock_page(page);
66 }
67 return page;
68}
69
70int __logfs_buf_write(struct logfs_area *area, u64 ofs, void *buf, size_t len,
71 int use_filler)
72{
73 pgoff_t index = ofs >> PAGE_SHIFT;
74 struct page *page;
75 long offset = ofs & (PAGE_SIZE-1);
76 long copylen;
77
78 /* Only logfs_wbuf_recover may use len==0 */
79 BUG_ON(!len && !use_filler);
80 do {
81 copylen = min((ulong)len, PAGE_SIZE - offset);
82
83 page = get_mapping_page(area->a_sb, index, use_filler);
84 if (IS_ERR(page))
85 return PTR_ERR(page);
86 BUG_ON(!page); /* FIXME: reserve a pool */
87 SetPageUptodate(page);
88 memcpy(page_address(page) + offset, buf, copylen);
89
90 if (!PagePrivate(page)) {
91 SetPagePrivate(page);
92 page_cache_get(page);
93 }
94 page_cache_release(page);
95
96 buf += copylen;
97 len -= copylen;
98 offset = 0;
99 index++;
100 } while (len);
101 return 0;
102}
103
104static void pad_partial_page(struct logfs_area *area)
105{
106 struct super_block *sb = area->a_sb;
107 struct page *page;
108 u64 ofs = dev_ofs(sb, area->a_segno, area->a_used_bytes);
109 pgoff_t index = ofs >> PAGE_SHIFT;
110 long offset = ofs & (PAGE_SIZE-1);
111 u32 len = PAGE_SIZE - offset;
112
113 if (len % PAGE_SIZE) {
114 page = get_mapping_page(sb, index, 0);
115 BUG_ON(!page); /* FIXME: reserve a pool */
116 memset(page_address(page) + offset, 0xff, len);
117 if (!PagePrivate(page)) {
118 SetPagePrivate(page);
119 page_cache_get(page);
120 }
121 page_cache_release(page);
122 }
123}
124
125static void pad_full_pages(struct logfs_area *area)
126{
127 struct super_block *sb = area->a_sb;
128 struct logfs_super *super = logfs_super(sb);
129 u64 ofs = dev_ofs(sb, area->a_segno, area->a_used_bytes);
130 u32 len = super->s_segsize - area->a_used_bytes;
131 pgoff_t index = PAGE_CACHE_ALIGN(ofs) >> PAGE_CACHE_SHIFT;
132 pgoff_t no_indizes = len >> PAGE_CACHE_SHIFT;
133 struct page *page;
134
135 while (no_indizes) {
136 page = get_mapping_page(sb, index, 0);
137 BUG_ON(!page); /* FIXME: reserve a pool */
138 SetPageUptodate(page);
139 memset(page_address(page), 0xff, PAGE_CACHE_SIZE);
140 if (!PagePrivate(page)) {
141 SetPagePrivate(page);
142 page_cache_get(page);
143 }
144 page_cache_release(page);
145 index++;
146 no_indizes--;
147 }
148}
149
150/*
151 * bdev_writeseg will write full pages. Memset the tail to prevent data leaks.
152 * Also make sure we allocate (and memset) all pages for final writeout.
153 */
154static void pad_wbuf(struct logfs_area *area, int final)
155{
156 pad_partial_page(area);
157 if (final)
158 pad_full_pages(area);
159}
160
161/*
162 * We have to be careful with the alias tree. Since lookup is done by bix,
163 * it needs to be normalized, so 14, 15, 16, etc. all match when dealing with
164 * indirect blocks. So always use it through accessor functions.
165 */
166static void *alias_tree_lookup(struct super_block *sb, u64 ino, u64 bix,
167 level_t level)
168{
169 struct btree_head128 *head = &logfs_super(sb)->s_object_alias_tree;
170 pgoff_t index = logfs_pack_index(bix, level);
171
172 return btree_lookup128(head, ino, index);
173}
174
175static int alias_tree_insert(struct super_block *sb, u64 ino, u64 bix,
176 level_t level, void *val)
177{
178 struct btree_head128 *head = &logfs_super(sb)->s_object_alias_tree;
179 pgoff_t index = logfs_pack_index(bix, level);
180
181 return btree_insert128(head, ino, index, val, GFP_NOFS);
182}
183
184static int btree_write_alias(struct super_block *sb, struct logfs_block *block,
185 write_alias_t *write_one_alias)
186{
187 struct object_alias_item *item;
188 int err;
189
190 list_for_each_entry(item, &block->item_list, list) {
191 err = write_alias_journal(sb, block->ino, block->bix,
192 block->level, item->child_no, item->val);
193 if (err)
194 return err;
195 }
196 return 0;
197}
198
199static struct logfs_block_ops btree_block_ops = {
200 .write_block = btree_write_block,
201 .free_block = __free_block,
202 .write_alias = btree_write_alias,
203};
204
205int logfs_load_object_aliases(struct super_block *sb,
206 struct logfs_obj_alias *oa, int count)
207{
208 struct logfs_super *super = logfs_super(sb);
209 struct logfs_block *block;
210 struct object_alias_item *item;
211 u64 ino, bix;
212 level_t level;
213 int i, err;
214
215 super->s_flags |= LOGFS_SB_FLAG_OBJ_ALIAS;
216 count /= sizeof(*oa);
217 for (i = 0; i < count; i++) {
218 item = mempool_alloc(super->s_alias_pool, GFP_NOFS);
219 if (!item)
220 return -ENOMEM;
221 memset(item, 0, sizeof(*item));
222
223 super->s_no_object_aliases++;
224 item->val = oa[i].val;
225 item->child_no = be16_to_cpu(oa[i].child_no);
226
227 ino = be64_to_cpu(oa[i].ino);
228 bix = be64_to_cpu(oa[i].bix);
229 level = LEVEL(oa[i].level);
230
231 log_aliases("logfs_load_object_aliases(%llx, %llx, %x, %x) %llx\n",
232 ino, bix, level, item->child_no,
233 be64_to_cpu(item->val));
234 block = alias_tree_lookup(sb, ino, bix, level);
235 if (!block) {
236 block = __alloc_block(sb, ino, bix, level);
237 block->ops = &btree_block_ops;
238 err = alias_tree_insert(sb, ino, bix, level, block);
239 BUG_ON(err); /* mempool empty */
240 }
241 if (test_and_set_bit(item->child_no, block->alias_map)) {
242 printk(KERN_ERR"LogFS: Alias collision detected\n");
243 return -EIO;
244 }
245 list_move_tail(&block->alias_list, &super->s_object_alias);
246 list_add(&item->list, &block->item_list);
247 }
248 return 0;
249}
250
251static void kill_alias(void *_block, unsigned long ignore0,
252 u64 ignore1, u64 ignore2, size_t ignore3)
253{
254 struct logfs_block *block = _block;
255 struct super_block *sb = block->sb;
256 struct logfs_super *super = logfs_super(sb);
257 struct object_alias_item *item;
258
259 while (!list_empty(&block->item_list)) {
260 item = list_entry(block->item_list.next, typeof(*item), list);
261 list_del(&item->list);
262 mempool_free(item, super->s_alias_pool);
263 }
264 block->ops->free_block(sb, block);
265}
266
267static int obj_type(struct inode *inode, level_t level)
268{
269 if (level == 0) {
270 if (S_ISDIR(inode->i_mode))
271 return OBJ_DENTRY;
272 if (inode->i_ino == LOGFS_INO_MASTER)
273 return OBJ_INODE;
274 }
275 return OBJ_BLOCK;
276}
277
278static int obj_len(struct super_block *sb, int obj_type)
279{
280 switch (obj_type) {
281 case OBJ_DENTRY:
282 return sizeof(struct logfs_disk_dentry);
283 case OBJ_INODE:
284 return sizeof(struct logfs_disk_inode);
285 case OBJ_BLOCK:
286 return sb->s_blocksize;
287 default:
288 BUG();
289 }
290}
291
292static int __logfs_segment_write(struct inode *inode, void *buf,
293 struct logfs_shadow *shadow, int type, int len, int compr)
294{
295 struct logfs_area *area;
296 struct super_block *sb = inode->i_sb;
297 s64 ofs;
298 struct logfs_object_header h;
299 int acc_len;
300
301 if (shadow->gc_level == 0)
302 acc_len = len;
303 else
304 acc_len = obj_len(sb, type);
305
306 area = get_area(sb, shadow->gc_level);
307 ofs = logfs_get_free_bytes(area, len + LOGFS_OBJECT_HEADERSIZE);
308 LOGFS_BUG_ON(ofs <= 0, sb);
309 /*
310 * Order is important. logfs_get_free_bytes(), by modifying the
311 * segment file, may modify the content of the very page we're about
312 * to write now. Which is fine, as long as the calculated crc and
313 * written data still match. So do the modifications _before_
314 * calculating the crc.
315 */
316
317 h.len = cpu_to_be16(len);
318 h.type = type;
319 h.compr = compr;
320 h.ino = cpu_to_be64(inode->i_ino);
321 h.bix = cpu_to_be64(shadow->bix);
322 h.crc = logfs_crc32(&h, sizeof(h) - 4, 4);
323 h.data_crc = logfs_crc32(buf, len, 0);
324
325 logfs_buf_write(area, ofs, &h, sizeof(h));
326 logfs_buf_write(area, ofs + LOGFS_OBJECT_HEADERSIZE, buf, len);
327
328 shadow->new_ofs = ofs;
329 shadow->new_len = acc_len + LOGFS_OBJECT_HEADERSIZE;
330
331 return 0;
332}
333
334static s64 logfs_segment_write_compress(struct inode *inode, void *buf,
335 struct logfs_shadow *shadow, int type, int len)
336{
337 struct super_block *sb = inode->i_sb;
338 void *compressor_buf = logfs_super(sb)->s_compressed_je;
339 ssize_t compr_len;
340 int ret;
341
342 mutex_lock(&logfs_super(sb)->s_journal_mutex);
343 compr_len = logfs_compress(buf, compressor_buf, len, len);
344
345 if (compr_len >= 0) {
346 ret = __logfs_segment_write(inode, compressor_buf, shadow,
347 type, compr_len, COMPR_ZLIB);
348 } else {
349 ret = __logfs_segment_write(inode, buf, shadow, type, len,
350 COMPR_NONE);
351 }
352 mutex_unlock(&logfs_super(sb)->s_journal_mutex);
353 return ret;
354}
355
356/**
357 * logfs_segment_write - write data block to object store
358 * @inode: inode containing data
359 *
360 * Returns an errno or zero.
361 */
362int logfs_segment_write(struct inode *inode, struct page *page,
363 struct logfs_shadow *shadow)
364{
365 struct super_block *sb = inode->i_sb;
366 struct logfs_super *super = logfs_super(sb);
367 int do_compress, type, len;
368 int ret;
369 void *buf;
370
371 super->s_flags |= LOGFS_SB_FLAG_DIRTY;
372 BUG_ON(super->s_flags & LOGFS_SB_FLAG_SHUTDOWN);
373 do_compress = logfs_inode(inode)->li_flags & LOGFS_IF_COMPRESSED;
374 if (shadow->gc_level != 0) {
375 /* temporarily disable compression for indirect blocks */
376 do_compress = 0;
377 }
378
379 type = obj_type(inode, shrink_level(shadow->gc_level));
380 len = obj_len(sb, type);
381 buf = kmap(page);
382 if (do_compress)
383 ret = logfs_segment_write_compress(inode, buf, shadow, type,
384 len);
385 else
386 ret = __logfs_segment_write(inode, buf, shadow, type, len,
387 COMPR_NONE);
388 kunmap(page);
389
390 log_segment("logfs_segment_write(%llx, %llx, %x) %llx->%llx %x->%x\n",
391 shadow->ino, shadow->bix, shadow->gc_level,
392 shadow->old_ofs, shadow->new_ofs,
393 shadow->old_len, shadow->new_len);
394 /* this BUG_ON did catch a locking bug. useful */
395 BUG_ON(!(shadow->new_ofs & (super->s_segsize - 1)));
396 return ret;
397}
398
399int wbuf_read(struct super_block *sb, u64 ofs, size_t len, void *buf)
400{
401 pgoff_t index = ofs >> PAGE_SHIFT;
402 struct page *page;
403 long offset = ofs & (PAGE_SIZE-1);
404 long copylen;
405
406 while (len) {
407 copylen = min((ulong)len, PAGE_SIZE - offset);
408
409 page = get_mapping_page(sb, index, 1);
410 if (IS_ERR(page))
411 return PTR_ERR(page);
412 memcpy(buf, page_address(page) + offset, copylen);
413 page_cache_release(page);
414
415 buf += copylen;
416 len -= copylen;
417 offset = 0;
418 index++;
419 }
420 return 0;
421}
422
423/*
424 * The "position" of indirect blocks is ambiguous. It can be the position
425 * of any data block somewhere behind this indirect block. So we need to
426 * normalize the positions through logfs_block_mask() before comparing.
427 */
428static int check_pos(struct super_block *sb, u64 pos1, u64 pos2, level_t level)
429{
430 return (pos1 & logfs_block_mask(sb, level)) !=
431 (pos2 & logfs_block_mask(sb, level));
432}
433
434#if 0
435static int read_seg_header(struct super_block *sb, u64 ofs,
436 struct logfs_segment_header *sh)
437{
438 __be32 crc;
439 int err;
440
441 err = wbuf_read(sb, ofs, sizeof(*sh), sh);
442 if (err)
443 return err;
444 crc = logfs_crc32(sh, sizeof(*sh), 4);
445 if (crc != sh->crc) {
446 printk(KERN_ERR"LOGFS: header crc error at %llx: expected %x, "
447 "got %x\n", ofs, be32_to_cpu(sh->crc),
448 be32_to_cpu(crc));
449 return -EIO;
450 }
451 return 0;
452}
453#endif
454
455static int read_obj_header(struct super_block *sb, u64 ofs,
456 struct logfs_object_header *oh)
457{
458 __be32 crc;
459 int err;
460
461 err = wbuf_read(sb, ofs, sizeof(*oh), oh);
462 if (err)
463 return err;
464 crc = logfs_crc32(oh, sizeof(*oh) - 4, 4);
465 if (crc != oh->crc) {
466 printk(KERN_ERR"LOGFS: header crc error at %llx: expected %x, "
467 "got %x\n", ofs, be32_to_cpu(oh->crc),
468 be32_to_cpu(crc));
469 return -EIO;
470 }
471 return 0;
472}
473
474static void move_btree_to_page(struct inode *inode, struct page *page,
475 __be64 *data)
476{
477 struct super_block *sb = inode->i_sb;
478 struct logfs_super *super = logfs_super(sb);
479 struct btree_head128 *head = &super->s_object_alias_tree;
480 struct logfs_block *block;
481 struct object_alias_item *item, *next;
482
483 if (!(super->s_flags & LOGFS_SB_FLAG_OBJ_ALIAS))
484 return;
485
486 block = btree_remove128(head, inode->i_ino, page->index);
487 if (!block)
488 return;
489
490 log_blockmove("move_btree_to_page(%llx, %llx, %x)\n",
491 block->ino, block->bix, block->level);
492 list_for_each_entry_safe(item, next, &block->item_list, list) {
493 data[item->child_no] = item->val;
494 list_del(&item->list);
495 mempool_free(item, super->s_alias_pool);
496 }
497 block->page = page;
498
499 if (!PagePrivate(page)) {
500 SetPagePrivate(page);
501 page_cache_get(page);
502 set_page_private(page, (unsigned long) block);
503 }
504 block->ops = &indirect_block_ops;
505 initialize_block_counters(page, block, data, 0);
506}
507
508/*
509 * This silences a false, yet annoying gcc warning. I hate it when my editor
510 * jumps into bitops.h each time I recompile this file.
511 * TODO: Complain to gcc folks about this and upgrade compiler.
512 */
513static unsigned long fnb(const unsigned long *addr,
514 unsigned long size, unsigned long offset)
515{
516 return find_next_bit(addr, size, offset);
517}
518
519void move_page_to_btree(struct page *page)
520{
521 struct logfs_block *block = logfs_block(page);
522 struct super_block *sb = block->sb;
523 struct logfs_super *super = logfs_super(sb);
524 struct object_alias_item *item;
525 unsigned long pos;
526 __be64 *child;
527 int err;
528
529 if (super->s_flags & LOGFS_SB_FLAG_SHUTDOWN) {
530 block->ops->free_block(sb, block);
531 return;
532 }
533 log_blockmove("move_page_to_btree(%llx, %llx, %x)\n",
534 block->ino, block->bix, block->level);
535 super->s_flags |= LOGFS_SB_FLAG_OBJ_ALIAS;
536
537 for (pos = 0; ; pos++) {
538 pos = fnb(block->alias_map, LOGFS_BLOCK_FACTOR, pos);
539 if (pos >= LOGFS_BLOCK_FACTOR)
540 break;
541
542 item = mempool_alloc(super->s_alias_pool, GFP_NOFS);
543 BUG_ON(!item); /* mempool empty */
544 memset(item, 0, sizeof(*item));
545
546 child = kmap_atomic(page);
547 item->val = child[pos];
548 kunmap_atomic(child);
549 item->child_no = pos;
550 list_add(&item->list, &block->item_list);
551 }
552 block->page = NULL;
553
554 if (PagePrivate(page)) {
555 ClearPagePrivate(page);
556 page_cache_release(page);
557 set_page_private(page, 0);
558 }
559 block->ops = &btree_block_ops;
560 err = alias_tree_insert(block->sb, block->ino, block->bix, block->level,
561 block);
562 BUG_ON(err); /* mempool empty */
563 ClearPageUptodate(page);
564}
565
566static int __logfs_segment_read(struct inode *inode, void *buf,
567 u64 ofs, u64 bix, level_t level)
568{
569 struct super_block *sb = inode->i_sb;
570 void *compressor_buf = logfs_super(sb)->s_compressed_je;
571 struct logfs_object_header oh;
572 __be32 crc;
573 u16 len;
574 int err, block_len;
575
576 block_len = obj_len(sb, obj_type(inode, level));
577 err = read_obj_header(sb, ofs, &oh);
578 if (err)
579 goto out_err;
580
581 err = -EIO;
582 if (be64_to_cpu(oh.ino) != inode->i_ino
583 || check_pos(sb, be64_to_cpu(oh.bix), bix, level)) {
584 printk(KERN_ERR"LOGFS: (ino, bix) don't match at %llx: "
585 "expected (%lx, %llx), got (%llx, %llx)\n",
586 ofs, inode->i_ino, bix,
587 be64_to_cpu(oh.ino), be64_to_cpu(oh.bix));
588 goto out_err;
589 }
590
591 len = be16_to_cpu(oh.len);
592
593 switch (oh.compr) {
594 case COMPR_NONE:
595 err = wbuf_read(sb, ofs + LOGFS_OBJECT_HEADERSIZE, len, buf);
596 if (err)
597 goto out_err;
598 crc = logfs_crc32(buf, len, 0);
599 if (crc != oh.data_crc) {
600 printk(KERN_ERR"LOGFS: uncompressed data crc error at "
601 "%llx: expected %x, got %x\n", ofs,
602 be32_to_cpu(oh.data_crc),
603 be32_to_cpu(crc));
604 goto out_err;
605 }
606 break;
607 case COMPR_ZLIB:
608 mutex_lock(&logfs_super(sb)->s_journal_mutex);
609 err = wbuf_read(sb, ofs + LOGFS_OBJECT_HEADERSIZE, len,
610 compressor_buf);
611 if (err) {
612 mutex_unlock(&logfs_super(sb)->s_journal_mutex);
613 goto out_err;
614 }
615 crc = logfs_crc32(compressor_buf, len, 0);
616 if (crc != oh.data_crc) {
617 printk(KERN_ERR"LOGFS: compressed data crc error at "
618 "%llx: expected %x, got %x\n", ofs,
619 be32_to_cpu(oh.data_crc),
620 be32_to_cpu(crc));
621 mutex_unlock(&logfs_super(sb)->s_journal_mutex);
622 goto out_err;
623 }
624 err = logfs_uncompress(compressor_buf, buf, len, block_len);
625 mutex_unlock(&logfs_super(sb)->s_journal_mutex);
626 if (err) {
627 printk(KERN_ERR"LOGFS: uncompress error at %llx\n", ofs);
628 goto out_err;
629 }
630 break;
631 default:
632 LOGFS_BUG(sb);
633 err = -EIO;
634 goto out_err;
635 }
636 return 0;
637
638out_err:
639 logfs_set_ro(sb);
640 printk(KERN_ERR"LOGFS: device is read-only now\n");
641 LOGFS_BUG(sb);
642 return err;
643}
644
645/**
646 * logfs_segment_read - read data block from object store
647 * @inode: inode containing data
648 * @buf: data buffer
649 * @ofs: physical data offset
650 * @bix: block index
651 * @level: block level
652 *
653 * Returns 0 on success or a negative errno.
654 */
655int logfs_segment_read(struct inode *inode, struct page *page,
656 u64 ofs, u64 bix, level_t level)
657{
658 int err;
659 void *buf;
660
661 if (PageUptodate(page))
662 return 0;
663
664 ofs &= ~LOGFS_FULLY_POPULATED;
665
666 buf = kmap(page);
667 err = __logfs_segment_read(inode, buf, ofs, bix, level);
668 if (!err) {
669 move_btree_to_page(inode, page, buf);
670 SetPageUptodate(page);
671 }
672 kunmap(page);
673 log_segment("logfs_segment_read(%lx, %llx, %x) %llx (%d)\n",
674 inode->i_ino, bix, level, ofs, err);
675 return err;
676}
677
678int logfs_segment_delete(struct inode *inode, struct logfs_shadow *shadow)
679{
680 struct super_block *sb = inode->i_sb;
681 struct logfs_super *super = logfs_super(sb);
682 struct logfs_object_header h;
683 u16 len;
684 int err;
685
686 super->s_flags |= LOGFS_SB_FLAG_DIRTY;
687 BUG_ON(super->s_flags & LOGFS_SB_FLAG_SHUTDOWN);
688 BUG_ON(shadow->old_ofs & LOGFS_FULLY_POPULATED);
689 if (!shadow->old_ofs)
690 return 0;
691
692 log_segment("logfs_segment_delete(%llx, %llx, %x) %llx->%llx %x->%x\n",
693 shadow->ino, shadow->bix, shadow->gc_level,
694 shadow->old_ofs, shadow->new_ofs,
695 shadow->old_len, shadow->new_len);
696 err = read_obj_header(sb, shadow->old_ofs, &h);
697 LOGFS_BUG_ON(err, sb);
698 LOGFS_BUG_ON(be64_to_cpu(h.ino) != inode->i_ino, sb);
699 LOGFS_BUG_ON(check_pos(sb, shadow->bix, be64_to_cpu(h.bix),
700 shrink_level(shadow->gc_level)), sb);
701
702 if (shadow->gc_level == 0)
703 len = be16_to_cpu(h.len);
704 else
705 len = obj_len(sb, h.type);
706 shadow->old_len = len + sizeof(h);
707 return 0;
708}
709
710void freeseg(struct super_block *sb, u32 segno)
711{
712 struct logfs_super *super = logfs_super(sb);
713 struct address_space *mapping = super->s_mapping_inode->i_mapping;
714 struct page *page;
715 u64 ofs, start, end;
716
717 start = dev_ofs(sb, segno, 0);
718 end = dev_ofs(sb, segno + 1, 0);
719 for (ofs = start; ofs < end; ofs += PAGE_SIZE) {
720 page = find_get_page(mapping, ofs >> PAGE_SHIFT);
721 if (!page)
722 continue;
723 if (PagePrivate(page)) {
724 ClearPagePrivate(page);
725 page_cache_release(page);
726 }
727 page_cache_release(page);
728 }
729}
730
731int logfs_open_area(struct logfs_area *area, size_t bytes)
732{
733 struct super_block *sb = area->a_sb;
734 struct logfs_super *super = logfs_super(sb);
735 int err, closed = 0;
736
737 if (area->a_is_open && area->a_used_bytes + bytes <= super->s_segsize)
738 return 0;
739
740 if (area->a_is_open) {
741 u64 ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes);
742 u32 len = super->s_segsize - area->a_written_bytes;
743
744 log_gc("logfs_close_area(%x)\n", area->a_segno);
745 pad_wbuf(area, 1);
746 super->s_devops->writeseg(area->a_sb, ofs, len);
747 freeseg(sb, area->a_segno);
748 closed = 1;
749 }
750
751 area->a_used_bytes = 0;
752 area->a_written_bytes = 0;
753again:
754 area->a_ops->get_free_segment(area);
755 area->a_ops->get_erase_count(area);
756
757 log_gc("logfs_open_area(%x, %x)\n", area->a_segno, area->a_level);
758 err = area->a_ops->erase_segment(area);
759 if (err) {
760 printk(KERN_WARNING "LogFS: Error erasing segment %x\n",
761 area->a_segno);
762 logfs_mark_segment_bad(sb, area->a_segno);
763 goto again;
764 }
765 area->a_is_open = 1;
766 return closed;
767}
768
769void logfs_sync_area(struct logfs_area *area)
770{
771 struct super_block *sb = area->a_sb;
772 struct logfs_super *super = logfs_super(sb);
773 u64 ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes);
774 u32 len = (area->a_used_bytes - area->a_written_bytes);
775
776 if (super->s_writesize)
777 len &= ~(super->s_writesize - 1);
778 if (len == 0)
779 return;
780 pad_wbuf(area, 0);
781 super->s_devops->writeseg(sb, ofs, len);
782 area->a_written_bytes += len;
783}
784
785void logfs_sync_segments(struct super_block *sb)
786{
787 struct logfs_super *super = logfs_super(sb);
788 int i;
789
790 for_each_area(i)
791 logfs_sync_area(super->s_area[i]);
792}
793
794/*
795 * Pick a free segment to be used for this area. Effectively takes a
796 * candidate from the free list (not really a candidate anymore).
797 */
798static void ostore_get_free_segment(struct logfs_area *area)
799{
800 struct super_block *sb = area->a_sb;
801 struct logfs_super *super = logfs_super(sb);
802
803 if (super->s_free_list.count == 0) {
804 printk(KERN_ERR"LOGFS: ran out of free segments\n");
805 LOGFS_BUG(sb);
806 }
807
808 area->a_segno = get_best_cand(sb, &super->s_free_list, NULL);
809}
810
811static void ostore_get_erase_count(struct logfs_area *area)
812{
813 struct logfs_segment_entry se;
814 u32 ec_level;
815
816 logfs_get_segment_entry(area->a_sb, area->a_segno, &se);
817 BUG_ON(se.ec_level == cpu_to_be32(BADSEG) ||
818 se.valid == cpu_to_be32(RESERVED));
819
820 ec_level = be32_to_cpu(se.ec_level);
821 area->a_erase_count = (ec_level >> 4) + 1;
822}
823
824static int ostore_erase_segment(struct logfs_area *area)
825{
826 struct super_block *sb = area->a_sb;
827 struct logfs_segment_header sh;
828 u64 ofs;
829 int err;
830
831 err = logfs_erase_segment(sb, area->a_segno, 0);
832 if (err)
833 return err;
834
835 sh.pad = 0;
836 sh.type = SEG_OSTORE;
837 sh.level = (__force u8)area->a_level;
838 sh.segno = cpu_to_be32(area->a_segno);
839 sh.ec = cpu_to_be32(area->a_erase_count);
840 sh.gec = cpu_to_be64(logfs_super(sb)->s_gec);
841 sh.crc = logfs_crc32(&sh, sizeof(sh), 4);
842
843 logfs_set_segment_erased(sb, area->a_segno, area->a_erase_count,
844 area->a_level);
845
846 ofs = dev_ofs(sb, area->a_segno, 0);
847 area->a_used_bytes = sizeof(sh);
848 logfs_buf_write(area, ofs, &sh, sizeof(sh));
849 return 0;
850}
851
852static const struct logfs_area_ops ostore_area_ops = {
853 .get_free_segment = ostore_get_free_segment,
854 .get_erase_count = ostore_get_erase_count,
855 .erase_segment = ostore_erase_segment,
856};
857
858static void free_area(struct logfs_area *area)
859{
860 if (area)
861 freeseg(area->a_sb, area->a_segno);
862 kfree(area);
863}
864
865void free_areas(struct super_block *sb)
866{
867 struct logfs_super *super = logfs_super(sb);
868 int i;
869
870 for_each_area(i)
871 free_area(super->s_area[i]);
872 free_area(super->s_journal_area);
873}
874
875static struct logfs_area *alloc_area(struct super_block *sb)
876{
877 struct logfs_area *area;
878
879 area = kzalloc(sizeof(*area), GFP_KERNEL);
880 if (!area)
881 return NULL;
882
883 area->a_sb = sb;
884 return area;
885}
886
887static void map_invalidatepage(struct page *page, unsigned long l)
888{
889 BUG();
890}
891
892static int map_releasepage(struct page *page, gfp_t g)
893{
894 /* Don't release these pages */
895 return 0;
896}
897
898static const struct address_space_operations mapping_aops = {
899 .invalidatepage = map_invalidatepage,
900 .releasepage = map_releasepage,
901 .set_page_dirty = __set_page_dirty_nobuffers,
902};
903
904int logfs_init_mapping(struct super_block *sb)
905{
906 struct logfs_super *super = logfs_super(sb);
907 struct address_space *mapping;
908 struct inode *inode;
909
910 inode = logfs_new_meta_inode(sb, LOGFS_INO_MAPPING);
911 if (IS_ERR(inode))
912 return PTR_ERR(inode);
913 super->s_mapping_inode = inode;
914 mapping = inode->i_mapping;
915 mapping->a_ops = &mapping_aops;
916 /* Would it be possible to use __GFP_HIGHMEM as well? */
917 mapping_set_gfp_mask(mapping, GFP_NOFS);
918 return 0;
919}
920
921int logfs_init_areas(struct super_block *sb)
922{
923 struct logfs_super *super = logfs_super(sb);
924 int i = -1;
925
926 super->s_alias_pool = mempool_create_kmalloc_pool(600,
927 sizeof(struct object_alias_item));
928 if (!super->s_alias_pool)
929 return -ENOMEM;
930
931 super->s_journal_area = alloc_area(sb);
932 if (!super->s_journal_area)
933 goto err;
934
935 for_each_area(i) {
936 super->s_area[i] = alloc_area(sb);
937 if (!super->s_area[i])
938 goto err;
939 super->s_area[i]->a_level = GC_LEVEL(i);
940 super->s_area[i]->a_ops = &ostore_area_ops;
941 }
942 btree_init_mempool128(&super->s_object_alias_tree,
943 super->s_btree_pool);
944 return 0;
945
946err:
947 for (i--; i >= 0; i--)
948 free_area(super->s_area[i]);
949 free_area(super->s_journal_area);
950 logfs_mempool_destroy(super->s_alias_pool);
951 return -ENOMEM;
952}
953
954void logfs_cleanup_areas(struct super_block *sb)
955{
956 struct logfs_super *super = logfs_super(sb);
957
958 btree_grim_visitor128(&super->s_object_alias_tree, 0, kill_alias);
959}