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Merge tag 'for-linus-20130628' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowe...
[linux-2.6.git] / fs / logfs / readwrite.c
blob9a59cbade2fb5254b2602ba8baf212676d62bca3
1 /*
2 * fs/logfs/readwrite.c
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 *
9 * Actually contains five sets of very similar functions:
10 * read read blocks from a file
11 * seek_hole find next hole
12 * seek_data find next data block
13 * valid check whether a block still belongs to a file
14 * write write blocks to a file
15 * delete delete a block (for directories and ifile)
16 * rewrite move existing blocks of a file to a new location (gc helper)
17 * truncate truncate a file
18 */
19 #include "logfs.h"
20 #include <linux/sched.h>
21 #include <linux/slab.h>
22
23 static u64 adjust_bix(u64 bix, level_t level)
24 {
25 switch (level) {
26 case 0:
27 return bix;
28 case LEVEL(1):
29 return max_t(u64, bix, I0_BLOCKS);
30 case LEVEL(2):
31 return max_t(u64, bix, I1_BLOCKS);
32 case LEVEL(3):
33 return max_t(u64, bix, I2_BLOCKS);
34 case LEVEL(4):
35 return max_t(u64, bix, I3_BLOCKS);
36 case LEVEL(5):
37 return max_t(u64, bix, I4_BLOCKS);
38 default:
39 WARN_ON(1);
40 return bix;
41 }
42 }
43
44 static inline u64 maxbix(u8 height)
45 {
46 return 1ULL << (LOGFS_BLOCK_BITS * height);
47 }
48
49 /**
50 * The inode address space is cut in two halves. Lower half belongs to data
51 * pages, upper half to indirect blocks. If the high bit (INDIRECT_BIT) is
52 * set, the actual block index (bix) and level can be derived from the page
53 * index.
54 *
55 * The lowest three bits of the block index are set to 0 after packing and
56 * unpacking. Since the lowest n bits (9 for 4KiB blocksize) are ignored
57 * anyway this is harmless.
58 */
59 #define ARCH_SHIFT (BITS_PER_LONG - 32)
60 #define INDIRECT_BIT (0x80000000UL << ARCH_SHIFT)
61 #define LEVEL_SHIFT (28 + ARCH_SHIFT)
62 static inline pgoff_t first_indirect_block(void)
63 {
64 return INDIRECT_BIT | (1ULL << LEVEL_SHIFT);
65 }
66
67 pgoff_t logfs_pack_index(u64 bix, level_t level)
68 {
69 pgoff_t index;
70
71 BUG_ON(bix >= INDIRECT_BIT);
72 if (level == 0)
73 return bix;
74
75 index = INDIRECT_BIT;
76 index |= (__force long)level << LEVEL_SHIFT;
77 index |= bix >> ((__force u8)level * LOGFS_BLOCK_BITS);
78 return index;
79 }
80
81 void logfs_unpack_index(pgoff_t index, u64 *bix, level_t *level)
82 {
83 u8 __level;
84
85 if (!(index & INDIRECT_BIT)) {
86 *bix = index;
87 *level = 0;
88 return;
89 }
90
91 __level = (index & ~INDIRECT_BIT) >> LEVEL_SHIFT;
92 *level = LEVEL(__level);
93 *bix = (index << (__level * LOGFS_BLOCK_BITS)) & ~INDIRECT_BIT;
94 *bix = adjust_bix(*bix, *level);
95 return;
96 }
97 #undef ARCH_SHIFT
98 #undef INDIRECT_BIT
99 #undef LEVEL_SHIFT
100
101 /*
102 * Time is stored as nanoseconds since the epoch.
103 */
104 static struct timespec be64_to_timespec(__be64 betime)
105 {
106 return ns_to_timespec(be64_to_cpu(betime));
107 }
108
109 static __be64 timespec_to_be64(struct timespec tsp)
110 {
111 return cpu_to_be64((u64)tsp.tv_sec * NSEC_PER_SEC + tsp.tv_nsec);
112 }
113
114 static void logfs_disk_to_inode(struct logfs_disk_inode *di, struct inode*inode)
115 {
116 struct logfs_inode *li = logfs_inode(inode);
117 int i;
118
119 inode->i_mode = be16_to_cpu(di->di_mode);
120 li->li_height = di->di_height;
121 li->li_flags = be32_to_cpu(di->di_flags);
122 i_uid_write(inode, be32_to_cpu(di->di_uid));
123 i_gid_write(inode, be32_to_cpu(di->di_gid));
124 inode->i_size = be64_to_cpu(di->di_size);
125 logfs_set_blocks(inode, be64_to_cpu(di->di_used_bytes));
126 inode->i_atime = be64_to_timespec(di->di_atime);
127 inode->i_ctime = be64_to_timespec(di->di_ctime);
128 inode->i_mtime = be64_to_timespec(di->di_mtime);
129 set_nlink(inode, be32_to_cpu(di->di_refcount));
130 inode->i_generation = be32_to_cpu(di->di_generation);
131
132 switch (inode->i_mode & S_IFMT) {
133 case S_IFSOCK: /* fall through */
134 case S_IFBLK: /* fall through */
135 case S_IFCHR: /* fall through */
136 case S_IFIFO:
137 inode->i_rdev = be64_to_cpu(di->di_data[0]);
138 break;
139 case S_IFDIR: /* fall through */
140 case S_IFREG: /* fall through */
141 case S_IFLNK:
142 for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
143 li->li_data[i] = be64_to_cpu(di->di_data[i]);
144 break;
145 default:
146 BUG();
147 }
148 }
149
150 static void logfs_inode_to_disk(struct inode *inode, struct logfs_disk_inode*di)
151 {
152 struct logfs_inode *li = logfs_inode(inode);
153 int i;
154
155 di->di_mode = cpu_to_be16(inode->i_mode);
156 di->di_height = li->li_height;
157 di->di_pad = 0;
158 di->di_flags = cpu_to_be32(li->li_flags);
159 di->di_uid = cpu_to_be32(i_uid_read(inode));
160 di->di_gid = cpu_to_be32(i_gid_read(inode));
161 di->di_size = cpu_to_be64(i_size_read(inode));
162 di->di_used_bytes = cpu_to_be64(li->li_used_bytes);
163 di->di_atime = timespec_to_be64(inode->i_atime);
164 di->di_ctime = timespec_to_be64(inode->i_ctime);
165 di->di_mtime = timespec_to_be64(inode->i_mtime);
166 di->di_refcount = cpu_to_be32(inode->i_nlink);
167 di->di_generation = cpu_to_be32(inode->i_generation);
168
169 switch (inode->i_mode & S_IFMT) {
170 case S_IFSOCK: /* fall through */
171 case S_IFBLK: /* fall through */
172 case S_IFCHR: /* fall through */
173 case S_IFIFO:
174 di->di_data[0] = cpu_to_be64(inode->i_rdev);
175 break;
176 case S_IFDIR: /* fall through */
177 case S_IFREG: /* fall through */
178 case S_IFLNK:
179 for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
180 di->di_data[i] = cpu_to_be64(li->li_data[i]);
181 break;
182 default:
183 BUG();
184 }
185 }
186
187 static void __logfs_set_blocks(struct inode *inode)
188 {
189 struct super_block *sb = inode->i_sb;
190 struct logfs_inode *li = logfs_inode(inode);
191
192 inode->i_blocks = ULONG_MAX;
193 if (li->li_used_bytes >> sb->s_blocksize_bits < ULONG_MAX)
194 inode->i_blocks = ALIGN(li->li_used_bytes, 512) >> 9;
195 }
196
197 void logfs_set_blocks(struct inode *inode, u64 bytes)
198 {
199 struct logfs_inode *li = logfs_inode(inode);
200
201 li->li_used_bytes = bytes;
202 __logfs_set_blocks(inode);
203 }
204
205 static void prelock_page(struct super_block *sb, struct page *page, int lock)
206 {
207 struct logfs_super *super = logfs_super(sb);
208
209 BUG_ON(!PageLocked(page));
210 if (lock) {
211 BUG_ON(PagePreLocked(page));
212 SetPagePreLocked(page);
213 } else {
214 /* We are in GC path. */
215 if (PagePreLocked(page))
216 super->s_lock_count++;
217 else
218 SetPagePreLocked(page);
219 }
220 }
221
222 static void preunlock_page(struct super_block *sb, struct page *page, int lock)
223 {
224 struct logfs_super *super = logfs_super(sb);
225
226 BUG_ON(!PageLocked(page));
227 if (lock)
228 ClearPagePreLocked(page);
229 else {
230 /* We are in GC path. */
231 BUG_ON(!PagePreLocked(page));
232 if (super->s_lock_count)
233 super->s_lock_count--;
234 else
235 ClearPagePreLocked(page);
236 }
237 }
238
239 /*
240 * Logfs is prone to an AB-BA deadlock where one task tries to acquire
241 * s_write_mutex with a locked page and GC tries to get that page while holding
242 * s_write_mutex.
243 * To solve this issue logfs will ignore the page lock iff the page in question
244 * is waiting for s_write_mutex. We annotate this fact by setting PG_pre_locked
245 * in addition to PG_locked.
246 */
247 void logfs_get_wblocks(struct super_block *sb, struct page *page, int lock)
248 {
249 struct logfs_super *super = logfs_super(sb);
250
251 if (page)
252 prelock_page(sb, page, lock);
253
254 if (lock) {
255 mutex_lock(&super->s_write_mutex);
256 logfs_gc_pass(sb);
257 /* FIXME: We also have to check for shadowed space
258 * and mempool fill grade */
259 }
260 }
261
262 void logfs_put_wblocks(struct super_block *sb, struct page *page, int lock)
263 {
264 struct logfs_super *super = logfs_super(sb);
265
266 if (page)
267 preunlock_page(sb, page, lock);
268 /* Order matters - we must clear PG_pre_locked before releasing
269 * s_write_mutex or we could race against another task. */
270 if (lock)
271 mutex_unlock(&super->s_write_mutex);
272 }
273
274 static struct page *logfs_get_read_page(struct inode *inode, u64 bix,
275 level_t level)
276 {
277 return find_or_create_page(inode->i_mapping,
278 logfs_pack_index(bix, level), GFP_NOFS);
279 }
280
281 static void logfs_put_read_page(struct page *page)
282 {
283 unlock_page(page);
284 page_cache_release(page);
285 }
286
287 static void logfs_lock_write_page(struct page *page)
288 {
289 int loop = 0;
290
291 while (unlikely(!trylock_page(page))) {
292 if (loop++ > 0x1000) {
293 /* Has been observed once so far... */
294 printk(KERN_ERR "stack at %p\n", &loop);
295 BUG();
296 }
297 if (PagePreLocked(page)) {
298 /* Holder of page lock is waiting for us, it
299 * is safe to use this page. */
300 break;
301 }
302 /* Some other process has this page locked and has
303 * nothing to do with us. Wait for it to finish.
304 */
305 schedule();
306 }
307 BUG_ON(!PageLocked(page));
308 }
309
310 static struct page *logfs_get_write_page(struct inode *inode, u64 bix,
311 level_t level)
312 {
313 struct address_space *mapping = inode->i_mapping;
314 pgoff_t index = logfs_pack_index(bix, level);
315 struct page *page;
316 int err;
317
318 repeat:
319 page = find_get_page(mapping, index);
320 if (!page) {
321 page = __page_cache_alloc(GFP_NOFS);
322 if (!page)
323 return NULL;
324 err = add_to_page_cache_lru(page, mapping, index, GFP_NOFS);
325 if (unlikely(err)) {
326 page_cache_release(page);
327 if (err == -EEXIST)
328 goto repeat;
329 return NULL;
330 }
331 } else logfs_lock_write_page(page);
332 BUG_ON(!PageLocked(page));
333 return page;
334 }
335
336 static void logfs_unlock_write_page(struct page *page)
337 {
338 if (!PagePreLocked(page))
339 unlock_page(page);
340 }
341
342 static void logfs_put_write_page(struct page *page)
343 {
344 logfs_unlock_write_page(page);
345 page_cache_release(page);
346 }
347
348 static struct page *logfs_get_page(struct inode *inode, u64 bix, level_t level,
349 int rw)
350 {
351 if (rw == READ)
352 return logfs_get_read_page(inode, bix, level);
353 else
354 return logfs_get_write_page(inode, bix, level);
355 }
356
357 static void logfs_put_page(struct page *page, int rw)
358 {
359 if (rw == READ)
360 logfs_put_read_page(page);
361 else
362 logfs_put_write_page(page);
363 }
364
365 static unsigned long __get_bits(u64 val, int skip, int no)
366 {
367 u64 ret = val;
368
369 ret >>= skip * no;
370 ret <<= 64 - no;
371 ret >>= 64 - no;
372 return ret;
373 }
374
375 static unsigned long get_bits(u64 val, level_t skip)
376 {
377 return __get_bits(val, (__force int)skip, LOGFS_BLOCK_BITS);
378 }
379
380 static inline void init_shadow_tree(struct super_block *sb,
381 struct shadow_tree *tree)
382 {
383 struct logfs_super *super = logfs_super(sb);
384
385 btree_init_mempool64(&tree->new, super->s_btree_pool);
386 btree_init_mempool64(&tree->old, super->s_btree_pool);
387 }
388
389 static void indirect_write_block(struct logfs_block *block)
390 {
391 struct page *page;
392 struct inode *inode;
393 int ret;
394
395 page = block->page;
396 inode = page->mapping->host;
397 logfs_lock_write_page(page);
398 ret = logfs_write_buf(inode, page, 0);
399 logfs_unlock_write_page(page);
400 /*
401 * This needs some rework. Unless you want your filesystem to run
402 * completely synchronously (you don't), the filesystem will always
403 * report writes as 'successful' before the actual work has been
404 * done. The actual work gets done here and this is where any errors
405 * will show up. And there isn't much we can do about it, really.
406 *
407 * Some attempts to fix the errors (move from bad blocks, retry io,...)
408 * have already been done, so anything left should be either a broken
409 * device or a bug somewhere in logfs itself. Being relatively new,
410 * the odds currently favor a bug, so for now the line below isn't
411 * entirely tasteles.
412 */
413 BUG_ON(ret);
414 }
415
416 static void inode_write_block(struct logfs_block *block)
417 {
418 struct inode *inode;
419 int ret;
420
421 inode = block->inode;
422 if (inode->i_ino == LOGFS_INO_MASTER)
423 logfs_write_anchor(inode->i_sb);
424 else {
425 ret = __logfs_write_inode(inode, NULL, 0);
426 /* see indirect_write_block comment */
427 BUG_ON(ret);
428 }
429 }
430
431 /*
432 * This silences a false, yet annoying gcc warning. I hate it when my editor
433 * jumps into bitops.h each time I recompile this file.
434 * TODO: Complain to gcc folks about this and upgrade compiler.
435 */
436 static unsigned long fnb(const unsigned long *addr,
437 unsigned long size, unsigned long offset)
438 {
439 return find_next_bit(addr, size, offset);
440 }
441
442 static __be64 inode_val0(struct inode *inode)
443 {
444 struct logfs_inode *li = logfs_inode(inode);
445 u64 val;
446
447 /*
448 * Explicit shifting generates good code, but must match the format
449 * of the structure. Add some paranoia just in case.
450 */
451 BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_mode) != 0);
452 BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_height) != 2);
453 BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_flags) != 4);
454
455 val = (u64)inode->i_mode << 48 |
456 (u64)li->li_height << 40 |
457 (u64)li->li_flags;
458 return cpu_to_be64(val);
459 }
460
461 static int inode_write_alias(struct super_block *sb,
462 struct logfs_block *block, write_alias_t *write_one_alias)
463 {
464 struct inode *inode = block->inode;
465 struct logfs_inode *li = logfs_inode(inode);
466 unsigned long pos;
467 u64 ino , bix;
468 __be64 val;
469 level_t level;
470 int err;
471
472 for (pos = 0; ; pos++) {
473 pos = fnb(block->alias_map, LOGFS_BLOCK_FACTOR, pos);
474 if (pos >= LOGFS_EMBEDDED_FIELDS + INODE_POINTER_OFS)
475 return 0;
476
477 switch (pos) {
478 case INODE_HEIGHT_OFS:
479 val = inode_val0(inode);
480 break;
481 case INODE_USED_OFS:
482 val = cpu_to_be64(li->li_used_bytes);
483 break;
484 case INODE_SIZE_OFS:
485 val = cpu_to_be64(i_size_read(inode));
486 break;
487 case INODE_POINTER_OFS ... INODE_POINTER_OFS + LOGFS_EMBEDDED_FIELDS - 1:
488 val = cpu_to_be64(li->li_data[pos - INODE_POINTER_OFS]);
489 break;
490 default:
491 BUG();
492 }
493
494 ino = LOGFS_INO_MASTER;
495 bix = inode->i_ino;
496 level = LEVEL(0);
497 err = write_one_alias(sb, ino, bix, level, pos, val);
498 if (err)
499 return err;
500 }
501 }
502
503 static int indirect_write_alias(struct super_block *sb,
504 struct logfs_block *block, write_alias_t *write_one_alias)
505 {
506 unsigned long pos;
507 struct page *page = block->page;
508 u64 ino , bix;
509 __be64 *child, val;
510 level_t level;
511 int err;
512
513 for (pos = 0; ; pos++) {
514 pos = fnb(block->alias_map, LOGFS_BLOCK_FACTOR, pos);
515 if (pos >= LOGFS_BLOCK_FACTOR)
516 return 0;
517
518 ino = page->mapping->host->i_ino;
519 logfs_unpack_index(page->index, &bix, &level);
520 child = kmap_atomic(page);
521 val = child[pos];
522 kunmap_atomic(child);
523 err = write_one_alias(sb, ino, bix, level, pos, val);
524 if (err)
525 return err;
526 }
527 }
528
529 int logfs_write_obj_aliases_pagecache(struct super_block *sb)
530 {
531 struct logfs_super *super = logfs_super(sb);
532 struct logfs_block *block;
533 int err;
534
535 list_for_each_entry(block, &super->s_object_alias, alias_list) {
536 err = block->ops->write_alias(sb, block, write_alias_journal);
537 if (err)
538 return err;
539 }
540 return 0;
541 }
542
543 void __free_block(struct super_block *sb, struct logfs_block *block)
544 {
545 BUG_ON(!list_empty(&block->item_list));
546 list_del(&block->alias_list);
547 mempool_free(block, logfs_super(sb)->s_block_pool);
548 }
549
550 static void inode_free_block(struct super_block *sb, struct logfs_block *block)
551 {
552 struct inode *inode = block->inode;
553
554 logfs_inode(inode)->li_block = NULL;
555 __free_block(sb, block);
556 }
557
558 static void indirect_free_block(struct super_block *sb,
559 struct logfs_block *block)
560 {
561 struct page *page = block->page;
562
563 if (PagePrivate(page)) {
564 ClearPagePrivate(page);
565 page_cache_release(page);
566 set_page_private(page, 0);
567 }
568 __free_block(sb, block);
569 }
570
571
572 static struct logfs_block_ops inode_block_ops = {
573 .write_block = inode_write_block,
574 .free_block = inode_free_block,
575 .write_alias = inode_write_alias,
576 };
577
578 struct logfs_block_ops indirect_block_ops = {
579 .write_block = indirect_write_block,
580 .free_block = indirect_free_block,
581 .write_alias = indirect_write_alias,
582 };
583
584 struct logfs_block *__alloc_block(struct super_block *sb,
585 u64 ino, u64 bix, level_t level)
586 {
587 struct logfs_super *super = logfs_super(sb);
588 struct logfs_block *block;
589
590 block = mempool_alloc(super->s_block_pool, GFP_NOFS);
591 memset(block, 0, sizeof(*block));
592 INIT_LIST_HEAD(&block->alias_list);
593 INIT_LIST_HEAD(&block->item_list);
594 block->sb = sb;
595 block->ino = ino;
596 block->bix = bix;
597 block->level = level;
598 return block;
599 }
600
601 static void alloc_inode_block(struct inode *inode)
602 {
603 struct logfs_inode *li = logfs_inode(inode);
604 struct logfs_block *block;
605
606 if (li->li_block)
607 return;
608
609 block = __alloc_block(inode->i_sb, LOGFS_INO_MASTER, inode->i_ino, 0);
610 block->inode = inode;
611 li->li_block = block;
612 block->ops = &inode_block_ops;
613 }
614
615 void initialize_block_counters(struct page *page, struct logfs_block *block,
616 __be64 *array, int page_is_empty)
617 {
618 u64 ptr;
619 int i, start;
620
621 block->partial = 0;
622 block->full = 0;
623 start = 0;
624 if (page->index < first_indirect_block()) {
625 /* Counters are pointless on level 0 */
626 return;
627 }
628 if (page->index == first_indirect_block()) {
629 /* Skip unused pointers */
630 start = I0_BLOCKS;
631 block->full = I0_BLOCKS;
632 }
633 if (!page_is_empty) {
634 for (i = start; i < LOGFS_BLOCK_FACTOR; i++) {
635 ptr = be64_to_cpu(array[i]);
636 if (ptr)
637 block->partial++;
638 if (ptr & LOGFS_FULLY_POPULATED)
639 block->full++;
640 }
641 }
642 }
643
644 static void alloc_data_block(struct inode *inode, struct page *page)
645 {
646 struct logfs_block *block;
647 u64 bix;
648 level_t level;
649
650 if (PagePrivate(page))
651 return;
652
653 logfs_unpack_index(page->index, &bix, &level);
654 block = __alloc_block(inode->i_sb, inode->i_ino, bix, level);
655 block->page = page;
656
657 SetPagePrivate(page);
658 page_cache_get(page);
659 set_page_private(page, (unsigned long) block);
660
661 block->ops = &indirect_block_ops;
662 }
663
664 static void alloc_indirect_block(struct inode *inode, struct page *page,
665 int page_is_empty)
666 {
667 struct logfs_block *block;
668 __be64 *array;
669
670 if (PagePrivate(page))
671 return;
672
673 alloc_data_block(inode, page);
674
675 block = logfs_block(page);
676 array = kmap_atomic(page);
677 initialize_block_counters(page, block, array, page_is_empty);
678 kunmap_atomic(array);
679 }
680
681 static void block_set_pointer(struct page *page, int index, u64 ptr)
682 {
683 struct logfs_block *block = logfs_block(page);
684 __be64 *array;
685 u64 oldptr;
686
687 BUG_ON(!block);
688 array = kmap_atomic(page);
689 oldptr = be64_to_cpu(array[index]);
690 array[index] = cpu_to_be64(ptr);
691 kunmap_atomic(array);
692 SetPageUptodate(page);
693
694 block->full += !!(ptr & LOGFS_FULLY_POPULATED)
695 - !!(oldptr & LOGFS_FULLY_POPULATED);
696 block->partial += !!ptr - !!oldptr;
697 }
698
699 static u64 block_get_pointer(struct page *page, int index)
700 {
701 __be64 *block;
702 u64 ptr;
703
704 block = kmap_atomic(page);
705 ptr = be64_to_cpu(block[index]);
706 kunmap_atomic(block);
707 return ptr;
708 }
709
710 static int logfs_read_empty(struct page *page)
711 {
712 zero_user_segment(page, 0, PAGE_CACHE_SIZE);
713 return 0;
714 }
715
716 static int logfs_read_direct(struct inode *inode, struct page *page)
717 {
718 struct logfs_inode *li = logfs_inode(inode);
719 pgoff_t index = page->index;
720 u64 block;
721
722 block = li->li_data[index];
723 if (!block)
724 return logfs_read_empty(page);
725
726 return logfs_segment_read(inode, page, block, index, 0);
727 }
728
729 static int logfs_read_loop(struct inode *inode, struct page *page,
730 int rw_context)
731 {
732 struct logfs_inode *li = logfs_inode(inode);
733 u64 bix, bofs = li->li_data[INDIRECT_INDEX];
734 level_t level, target_level;
735 int ret;
736 struct page *ipage;
737
738 logfs_unpack_index(page->index, &bix, &target_level);
739 if (!bofs)
740 return logfs_read_empty(page);
741
742 if (bix >= maxbix(li->li_height))
743 return logfs_read_empty(page);
744
745 for (level = LEVEL(li->li_height);
746 (__force u8)level > (__force u8)target_level;
747 level = SUBLEVEL(level)){
748 ipage = logfs_get_page(inode, bix, level, rw_context);
749 if (!ipage)
750 return -ENOMEM;
751
752 ret = logfs_segment_read(inode, ipage, bofs, bix, level);
753 if (ret) {
754 logfs_put_read_page(ipage);
755 return ret;
756 }
757
758 bofs = block_get_pointer(ipage, get_bits(bix, SUBLEVEL(level)));
759 logfs_put_page(ipage, rw_context);
760 if (!bofs)
761 return logfs_read_empty(page);
762 }
763
764 return logfs_segment_read(inode, page, bofs, bix, 0);
765 }
766
767 static int logfs_read_block(struct inode *inode, struct page *page,
768 int rw_context)
769 {
770 pgoff_t index = page->index;
771
772 if (index < I0_BLOCKS)
773 return logfs_read_direct(inode, page);
774 return logfs_read_loop(inode, page, rw_context);
775 }
776
777 static int logfs_exist_loop(struct inode *inode, u64 bix)
778 {
779 struct logfs_inode *li = logfs_inode(inode);
780 u64 bofs = li->li_data[INDIRECT_INDEX];
781 level_t level;
782 int ret;
783 struct page *ipage;
784
785 if (!bofs)
786 return 0;
787 if (bix >= maxbix(li->li_height))
788 return 0;
789
790 for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)) {
791 ipage = logfs_get_read_page(inode, bix, level);
792 if (!ipage)
793 return -ENOMEM;
794
795 ret = logfs_segment_read(inode, ipage, bofs, bix, level);
796 if (ret) {
797 logfs_put_read_page(ipage);
798 return ret;
799 }
800
801 bofs = block_get_pointer(ipage, get_bits(bix, SUBLEVEL(level)));
802 logfs_put_read_page(ipage);
803 if (!bofs)
804 return 0;
805 }
806
807 return 1;
808 }
809
810 int logfs_exist_block(struct inode *inode, u64 bix)
811 {
812 struct logfs_inode *li = logfs_inode(inode);
813
814 if (bix < I0_BLOCKS)
815 return !!li->li_data[bix];
816 return logfs_exist_loop(inode, bix);
817 }
818
819 static u64 seek_holedata_direct(struct inode *inode, u64 bix, int data)
820 {
821 struct logfs_inode *li = logfs_inode(inode);
822
823 for (; bix < I0_BLOCKS; bix++)
824 if (data ^ (li->li_data[bix] == 0))
825 return bix;
826 return I0_BLOCKS;
827 }
828
829 static u64 seek_holedata_loop(struct inode *inode, u64 bix, int data)
830 {
831 struct logfs_inode *li = logfs_inode(inode);
832 __be64 *rblock;
833 u64 increment, bofs = li->li_data[INDIRECT_INDEX];
834 level_t level;
835 int ret, slot;
836 struct page *page;
837
838 BUG_ON(!bofs);
839
840 for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)) {
841 increment = 1 << (LOGFS_BLOCK_BITS * ((__force u8)level-1));
842 page = logfs_get_read_page(inode, bix, level);
843 if (!page)
844 return bix;
845
846 ret = logfs_segment_read(inode, page, bofs, bix, level);
847 if (ret) {
848 logfs_put_read_page(page);
849 return bix;
850 }
851
852 slot = get_bits(bix, SUBLEVEL(level));
853 rblock = kmap_atomic(page);
854 while (slot < LOGFS_BLOCK_FACTOR) {
855 if (data && (rblock[slot] != 0))
856 break;
857 if (!data && !(be64_to_cpu(rblock[slot]) & LOGFS_FULLY_POPULATED))
858 break;
859 slot++;
860 bix += increment;
861 bix &= ~(increment - 1);
862 }
863 if (slot >= LOGFS_BLOCK_FACTOR) {
864 kunmap_atomic(rblock);
865 logfs_put_read_page(page);
866 return bix;
867 }
868 bofs = be64_to_cpu(rblock[slot]);
869 kunmap_atomic(rblock);
870 logfs_put_read_page(page);
871 if (!bofs) {
872 BUG_ON(data);
873 return bix;
874 }
875 }
876 return bix;
877 }
878
879 /**
880 * logfs_seek_hole - find next hole starting at a given block index
881 * @inode: inode to search in
882 * @bix: block index to start searching
883 *
884 * Returns next hole. If the file doesn't contain any further holes, the
885 * block address next to eof is returned instead.
886 */
887 u64 logfs_seek_hole(struct inode *inode, u64 bix)
888 {
889 struct logfs_inode *li = logfs_inode(inode);
890
891 if (bix < I0_BLOCKS) {
892 bix = seek_holedata_direct(inode, bix, 0);
893 if (bix < I0_BLOCKS)
894 return bix;
895 }
896
897 if (!li->li_data[INDIRECT_INDEX])
898 return bix;
899 else if (li->li_data[INDIRECT_INDEX] & LOGFS_FULLY_POPULATED)
900 bix = maxbix(li->li_height);
901 else if (bix >= maxbix(li->li_height))
902 return bix;
903 else {
904 bix = seek_holedata_loop(inode, bix, 0);
905 if (bix < maxbix(li->li_height))
906 return bix;
907 /* Should not happen anymore. But if some port writes semi-
908 * corrupt images (as this one used to) we might run into it.
909 */
910 WARN_ON_ONCE(bix == maxbix(li->li_height));
911 }
912
913 return bix;
914 }
915
916 static u64 __logfs_seek_data(struct inode *inode, u64 bix)
917 {
918 struct logfs_inode *li = logfs_inode(inode);
919
920 if (bix < I0_BLOCKS) {
921 bix = seek_holedata_direct(inode, bix, 1);
922 if (bix < I0_BLOCKS)
923 return bix;
924 }
925
926 if (bix < maxbix(li->li_height)) {
927 if (!li->li_data[INDIRECT_INDEX])
928 bix = maxbix(li->li_height);
929 else
930 return seek_holedata_loop(inode, bix, 1);
931 }
932
933 return bix;
934 }
935
936 /**
937 * logfs_seek_data - find next data block after a given block index
938 * @inode: inode to search in
939 * @bix: block index to start searching
940 *
941 * Returns next data block. If the file doesn't contain any further data
942 * blocks, the last block in the file is returned instead.
943 */
944 u64 logfs_seek_data(struct inode *inode, u64 bix)
945 {
946 struct super_block *sb = inode->i_sb;
947 u64 ret, end;
948
949 ret = __logfs_seek_data(inode, bix);
950 end = i_size_read(inode) >> sb->s_blocksize_bits;
951 if (ret >= end)
952 ret = max(bix, end);
953 return ret;
954 }
955
956 static int logfs_is_valid_direct(struct logfs_inode *li, u64 bix, u64 ofs)
957 {
958 return pure_ofs(li->li_data[bix]) == ofs;
959 }
960
961 static int __logfs_is_valid_loop(struct inode *inode, u64 bix,
962 u64 ofs, u64 bofs)
963 {
964 struct logfs_inode *li = logfs_inode(inode);
965 level_t level;
966 int ret;
967 struct page *page;
968
969 for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)){
970 page = logfs_get_write_page(inode, bix, level);
971 BUG_ON(!page);
972
973 ret = logfs_segment_read(inode, page, bofs, bix, level);
974 if (ret) {
975 logfs_put_write_page(page);
976 return 0;
977 }
978
979 bofs = block_get_pointer(page, get_bits(bix, SUBLEVEL(level)));
980 logfs_put_write_page(page);
981 if (!bofs)
982 return 0;
983
984 if (pure_ofs(bofs) == ofs)
985 return 1;
986 }
987 return 0;
988 }
989
990 static int logfs_is_valid_loop(struct inode *inode, u64 bix, u64 ofs)
991 {
992 struct logfs_inode *li = logfs_inode(inode);
993 u64 bofs = li->li_data[INDIRECT_INDEX];
994
995 if (!bofs)
996 return 0;
997
998 if (bix >= maxbix(li->li_height))
999 return 0;
1000
1001 if (pure_ofs(bofs) == ofs)
1002 return 1;
1003
1004 return __logfs_is_valid_loop(inode, bix, ofs, bofs);
1005 }
1006
1007 static int __logfs_is_valid_block(struct inode *inode, u64 bix, u64 ofs)
1008 {
1009 struct logfs_inode *li = logfs_inode(inode);
1010
1011 if ((inode->i_nlink == 0) && atomic_read(&inode->i_count) == 1)
1012 return 0;
1013
1014 if (bix < I0_BLOCKS)
1015 return logfs_is_valid_direct(li, bix, ofs);
1016 return logfs_is_valid_loop(inode, bix, ofs);
1017 }
1018
1019 /**
1020 * logfs_is_valid_block - check whether this block is still valid
1021 *
1022 * @sb - superblock
1023 * @ofs - block physical offset
1024 * @ino - block inode number
1025 * @bix - block index
1026 * @level - block level
1027 *
1028 * Returns 0 if the block is invalid, 1 if it is valid and 2 if it will
1029 * become invalid once the journal is written.
1030 */
1031 int logfs_is_valid_block(struct super_block *sb, u64 ofs, u64 ino, u64 bix,
1032 gc_level_t gc_level)
1033 {
1034 struct logfs_super *super = logfs_super(sb);
1035 struct inode *inode;
1036 int ret, cookie;
1037
1038 /* Umount closes a segment with free blocks remaining. Those
1039 * blocks are by definition invalid. */
1040 if (ino == -1)
1041 return 0;
1042
1043 LOGFS_BUG_ON((u64)(u_long)ino != ino, sb);
1044
1045 inode = logfs_safe_iget(sb, ino, &cookie);
1046 if (IS_ERR(inode))
1047 goto invalid;
1048
1049 ret = __logfs_is_valid_block(inode, bix, ofs);
1050 logfs_safe_iput(inode, cookie);
1051 if (ret)
1052 return ret;
1053
1054 invalid:
1055 /* Block is nominally invalid, but may still sit in the shadow tree,
1056 * waiting for a journal commit.
1057 */
1058 if (btree_lookup64(&super->s_shadow_tree.old, ofs))
1059 return 2;
1060 return 0;
1061 }
1062
1063 int logfs_readpage_nolock(struct page *page)
1064 {
1065 struct inode *inode = page->mapping->host;
1066 int ret = -EIO;
1067
1068 ret = logfs_read_block(inode, page, READ);
1069
1070 if (ret) {
1071 ClearPageUptodate(page);
1072 SetPageError(page);
1073 } else {
1074 SetPageUptodate(page);
1075 ClearPageError(page);
1076 }
1077 flush_dcache_page(page);
1078
1079 return ret;
1080 }
1081
1082 static int logfs_reserve_bytes(struct inode *inode, int bytes)
1083 {
1084 struct logfs_super *super = logfs_super(inode->i_sb);
1085 u64 available = super->s_free_bytes + super->s_dirty_free_bytes
1086 - super->s_dirty_used_bytes - super->s_dirty_pages;
1087
1088 if (!bytes)
1089 return 0;
1090
1091 if (available < bytes)
1092 return -ENOSPC;
1093
1094 if (available < bytes + super->s_root_reserve &&
1095 !capable(CAP_SYS_RESOURCE))
1096 return -ENOSPC;
1097
1098 return 0;
1099 }
1100
1101 int get_page_reserve(struct inode *inode, struct page *page)
1102 {
1103 struct logfs_super *super = logfs_super(inode->i_sb);
1104 struct logfs_block *block = logfs_block(page);
1105 int ret;
1106
1107 if (block && block->reserved_bytes)
1108 return 0;
1109
1110 logfs_get_wblocks(inode->i_sb, page, WF_LOCK);
1111 while ((ret = logfs_reserve_bytes(inode, 6 * LOGFS_MAX_OBJECTSIZE)) &&
1112 !list_empty(&super->s_writeback_list)) {
1113 block = list_entry(super->s_writeback_list.next,
1114 struct logfs_block, alias_list);
1115 block->ops->write_block(block);
1116 }
1117 if (!ret) {
1118 alloc_data_block(inode, page);
1119 block = logfs_block(page);
1120 block->reserved_bytes += 6 * LOGFS_MAX_OBJECTSIZE;
1121 super->s_dirty_pages += 6 * LOGFS_MAX_OBJECTSIZE;
1122 list_move_tail(&block->alias_list, &super->s_writeback_list);
1123 }
1124 logfs_put_wblocks(inode->i_sb, page, WF_LOCK);
1125 return ret;
1126 }
1127
1128 /*
1129 * We are protected by write lock. Push victims up to superblock level
1130 * and release transaction when appropriate.
1131 */
1132 /* FIXME: This is currently called from the wrong spots. */
1133 static void logfs_handle_transaction(struct inode *inode,
1134 struct logfs_transaction *ta)
1135 {
1136 struct logfs_super *super = logfs_super(inode->i_sb);
1137
1138 if (!ta)
1139 return;
1140 logfs_inode(inode)->li_block->ta = NULL;
1141
1142 if (inode->i_ino != LOGFS_INO_MASTER) {
1143 BUG(); /* FIXME: Yes, this needs more thought */
1144 /* just remember the transaction until inode is written */
1145 //BUG_ON(logfs_inode(inode)->li_transaction);
1146 //logfs_inode(inode)->li_transaction = ta;
1147 return;
1148 }
1149
1150 switch (ta->state) {
1151 case CREATE_1: /* fall through */
1152 case UNLINK_1:
1153 BUG_ON(super->s_victim_ino);
1154 super->s_victim_ino = ta->ino;
1155 break;
1156 case CREATE_2: /* fall through */
1157 case UNLINK_2:
1158 BUG_ON(super->s_victim_ino != ta->ino);
1159 super->s_victim_ino = 0;
1160 /* transaction ends here - free it */
1161 kfree(ta);
1162 break;
1163 case CROSS_RENAME_1:
1164 BUG_ON(super->s_rename_dir);
1165 BUG_ON(super->s_rename_pos);
1166 super->s_rename_dir = ta->dir;
1167 super->s_rename_pos = ta->pos;
1168 break;
1169 case CROSS_RENAME_2:
1170 BUG_ON(super->s_rename_dir != ta->dir);
1171 BUG_ON(super->s_rename_pos != ta->pos);
1172 super->s_rename_dir = 0;
1173 super->s_rename_pos = 0;
1174 kfree(ta);
1175 break;
1176 case TARGET_RENAME_1:
1177 BUG_ON(super->s_rename_dir);
1178 BUG_ON(super->s_rename_pos);
1179 BUG_ON(super->s_victim_ino);
1180 super->s_rename_dir = ta->dir;
1181 super->s_rename_pos = ta->pos;
1182 super->s_victim_ino = ta->ino;
1183 break;
1184 case TARGET_RENAME_2:
1185 BUG_ON(super->s_rename_dir != ta->dir);
1186 BUG_ON(super->s_rename_pos != ta->pos);
1187 BUG_ON(super->s_victim_ino != ta->ino);
1188 super->s_rename_dir = 0;
1189 super->s_rename_pos = 0;
1190 break;
1191 case TARGET_RENAME_3:
1192 BUG_ON(super->s_rename_dir);
1193 BUG_ON(super->s_rename_pos);
1194 BUG_ON(super->s_victim_ino != ta->ino);
1195 super->s_victim_ino = 0;
1196 kfree(ta);
1197 break;
1198 default:
1199 BUG();
1200 }
1201 }
1202
1203 /*
1204 * Not strictly a reservation, but rather a check that we still have enough
1205 * space to satisfy the write.
1206 */
1207 static int logfs_reserve_blocks(struct inode *inode, int blocks)
1208 {
1209 return logfs_reserve_bytes(inode, blocks * LOGFS_MAX_OBJECTSIZE);
1210 }
1211
1212 struct write_control {
1213 u64 ofs;
1214 long flags;
1215 };
1216
1217 static struct logfs_shadow *alloc_shadow(struct inode *inode, u64 bix,
1218 level_t level, u64 old_ofs)
1219 {
1220 struct logfs_super *super = logfs_super(inode->i_sb);
1221 struct logfs_shadow *shadow;
1222
1223 shadow = mempool_alloc(super->s_shadow_pool, GFP_NOFS);
1224 memset(shadow, 0, sizeof(*shadow));
1225 shadow->ino = inode->i_ino;
1226 shadow->bix = bix;
1227 shadow->gc_level = expand_level(inode->i_ino, level);
1228 shadow->old_ofs = old_ofs & ~LOGFS_FULLY_POPULATED;
1229 return shadow;
1230 }
1231
1232 static void free_shadow(struct inode *inode, struct logfs_shadow *shadow)
1233 {
1234 struct logfs_super *super = logfs_super(inode->i_sb);
1235
1236 mempool_free(shadow, super->s_shadow_pool);
1237 }
1238
1239 static void mark_segment(struct shadow_tree *tree, u32 segno)
1240 {
1241 int err;
1242
1243 if (!btree_lookup32(&tree->segment_map, segno)) {
1244 err = btree_insert32(&tree->segment_map, segno, (void *)1,
1245 GFP_NOFS);
1246 BUG_ON(err);
1247 tree->no_shadowed_segments++;
1248 }
1249 }
1250
1251 /**
1252 * fill_shadow_tree - Propagate shadow tree changes due to a write
1253 * @inode: Inode owning the page
1254 * @page: Struct page that was written
1255 * @shadow: Shadow for the current write
1256 *
1257 * Writes in logfs can result in two semi-valid objects. The old object
1258 * is still valid as long as it can be reached by following pointers on
1259 * the medium. Only when writes propagate all the way up to the journal
1260 * has the new object safely replaced the old one.
1261 *
1262 * To handle this problem, a struct logfs_shadow is used to represent
1263 * every single write. It is attached to the indirect block, which is
1264 * marked dirty. When the indirect block is written, its shadows are
1265 * handed up to the next indirect block (or inode). Untimately they
1266 * will reach the master inode and be freed upon journal commit.
1267 *
1268 * This function handles a single step in the propagation. It adds the
1269 * shadow for the current write to the tree, along with any shadows in
1270 * the page's tree, in case it was an indirect block. If a page is
1271 * written, the inode parameter is left NULL, if an inode is written,
1272 * the page parameter is left NULL.
1273 */
1274 static void fill_shadow_tree(struct inode *inode, struct page *page,
1275 struct logfs_shadow *shadow)
1276 {
1277 struct logfs_super *super = logfs_super(inode->i_sb);
1278 struct logfs_block *block = logfs_block(page);
1279 struct shadow_tree *tree = &super->s_shadow_tree;
1280
1281 if (PagePrivate(page)) {
1282 if (block->alias_map)
1283 super->s_no_object_aliases -= bitmap_weight(
1284 block->alias_map, LOGFS_BLOCK_FACTOR);
1285 logfs_handle_transaction(inode, block->ta);
1286 block->ops->free_block(inode->i_sb, block);
1287 }
1288 if (shadow) {
1289 if (shadow->old_ofs)
1290 btree_insert64(&tree->old, shadow->old_ofs, shadow,
1291 GFP_NOFS);
1292 else
1293 btree_insert64(&tree->new, shadow->new_ofs, shadow,
1294 GFP_NOFS);
1295
1296 super->s_dirty_used_bytes += shadow->new_len;
1297 super->s_dirty_free_bytes += shadow->old_len;
1298 mark_segment(tree, shadow->old_ofs >> super->s_segshift);
1299 mark_segment(tree, shadow->new_ofs >> super->s_segshift);
1300 }
1301 }
1302
1303 static void logfs_set_alias(struct super_block *sb, struct logfs_block *block,
1304 long child_no)
1305 {
1306 struct logfs_super *super = logfs_super(sb);
1307
1308 if (block->inode && block->inode->i_ino == LOGFS_INO_MASTER) {
1309 /* Aliases in the master inode are pointless. */
1310 return;
1311 }
1312
1313 if (!test_bit(child_no, block->alias_map)) {
1314 set_bit(child_no, block->alias_map);
1315 super->s_no_object_aliases++;
1316 }
1317 list_move_tail(&block->alias_list, &super->s_object_alias);
1318 }
1319
1320 /*
1321 * Object aliases can and often do change the size and occupied space of a
1322 * file. So not only do we have to change the pointers, we also have to
1323 * change inode->i_size and li->li_used_bytes. Which is done by setting
1324 * another two object aliases for the inode itself.
1325 */
1326 static void set_iused(struct inode *inode, struct logfs_shadow *shadow)
1327 {
1328 struct logfs_inode *li = logfs_inode(inode);
1329
1330 if (shadow->new_len == shadow->old_len)
1331 return;
1332
1333 alloc_inode_block(inode);
1334 li->li_used_bytes += shadow->new_len - shadow->old_len;
1335 __logfs_set_blocks(inode);
1336 logfs_set_alias(inode->i_sb, li->li_block, INODE_USED_OFS);
1337 logfs_set_alias(inode->i_sb, li->li_block, INODE_SIZE_OFS);
1338 }
1339
1340 static int logfs_write_i0(struct inode *inode, struct page *page,
1341 struct write_control *wc)
1342 {
1343 struct logfs_shadow *shadow;
1344 u64 bix;
1345 level_t level;
1346 int full, err = 0;
1347
1348 logfs_unpack_index(page->index, &bix, &level);
1349 if (wc->ofs == 0)
1350 if (logfs_reserve_blocks(inode, 1))
1351 return -ENOSPC;
1352
1353 shadow = alloc_shadow(inode, bix, level, wc->ofs);
1354 if (wc->flags & WF_WRITE)
1355 err = logfs_segment_write(inode, page, shadow);
1356 if (wc->flags & WF_DELETE)
1357 logfs_segment_delete(inode, shadow);
1358 if (err) {
1359 free_shadow(inode, shadow);
1360 return err;
1361 }
1362
1363 set_iused(inode, shadow);
1364 full = 1;
1365 if (level != 0) {
1366 alloc_indirect_block(inode, page, 0);
1367 full = logfs_block(page)->full == LOGFS_BLOCK_FACTOR;
1368 }
1369 fill_shadow_tree(inode, page, shadow);
1370 wc->ofs = shadow->new_ofs;
1371 if (wc->ofs && full)
1372 wc->ofs |= LOGFS_FULLY_POPULATED;
1373 return 0;
1374 }
1375
1376 static int logfs_write_direct(struct inode *inode, struct page *page,
1377 long flags)
1378 {
1379 struct logfs_inode *li = logfs_inode(inode);
1380 struct write_control wc = {
1381 .ofs = li->li_data[page->index],
1382 .flags = flags,
1383 };
1384 int err;
1385
1386 alloc_inode_block(inode);
1387
1388 err = logfs_write_i0(inode, page, &wc);
1389 if (err)
1390 return err;
1391
1392 li->li_data[page->index] = wc.ofs;
1393 logfs_set_alias(inode->i_sb, li->li_block,
1394 page->index + INODE_POINTER_OFS);
1395 return 0;
1396 }
1397
1398 static int ptr_change(u64 ofs, struct page *page)
1399 {
1400 struct logfs_block *block = logfs_block(page);
1401 int empty0, empty1, full0, full1;
1402
1403 empty0 = ofs == 0;
1404 empty1 = block->partial == 0;
1405 if (empty0 != empty1)
1406 return 1;
1407
1408 /* The !! is necessary to shrink result to int */
1409 full0 = !!(ofs & LOGFS_FULLY_POPULATED);
1410 full1 = block->full == LOGFS_BLOCK_FACTOR;
1411 if (full0 != full1)
1412 return 1;
1413 return 0;
1414 }
1415
1416 static int __logfs_write_rec(struct inode *inode, struct page *page,
1417 struct write_control *this_wc,
1418 pgoff_t bix, level_t target_level, level_t level)
1419 {
1420 int ret, page_empty = 0;
1421 int child_no = get_bits(bix, SUBLEVEL(level));
1422 struct page *ipage;
1423 struct write_control child_wc = {
1424 .flags = this_wc->flags,
1425 };
1426
1427 ipage = logfs_get_write_page(inode, bix, level);
1428 if (!ipage)
1429 return -ENOMEM;
1430
1431 if (this_wc->ofs) {
1432 ret = logfs_segment_read(inode, ipage, this_wc->ofs, bix, level);
1433 if (ret)
1434 goto out;
1435 } else if (!PageUptodate(ipage)) {
1436 page_empty = 1;
1437 logfs_read_empty(ipage);
1438 }
1439
1440 child_wc.ofs = block_get_pointer(ipage, child_no);
1441
1442 if ((__force u8)level-1 > (__force u8)target_level)
1443 ret = __logfs_write_rec(inode, page, &child_wc, bix,
1444 target_level, SUBLEVEL(level));
1445 else
1446 ret = logfs_write_i0(inode, page, &child_wc);
1447
1448 if (ret)
1449 goto out;
1450
1451 alloc_indirect_block(inode, ipage, page_empty);
1452 block_set_pointer(ipage, child_no, child_wc.ofs);
1453 /* FIXME: first condition seems superfluous */
1454 if (child_wc.ofs || logfs_block(ipage)->partial)
1455 this_wc->flags |= WF_WRITE;
1456 /* the condition on this_wc->ofs ensures that we won't consume extra
1457 * space for indirect blocks in the future, which we cannot reserve */
1458 if (!this_wc->ofs || ptr_change(this_wc->ofs, ipage))
1459 ret = logfs_write_i0(inode, ipage, this_wc);
1460 else
1461 logfs_set_alias(inode->i_sb, logfs_block(ipage), child_no);
1462 out:
1463 logfs_put_write_page(ipage);
1464 return ret;
1465 }
1466
1467 static int logfs_write_rec(struct inode *inode, struct page *page,
1468 pgoff_t bix, level_t target_level, long flags)
1469 {
1470 struct logfs_inode *li = logfs_inode(inode);
1471 struct write_control wc = {
1472 .ofs = li->li_data[INDIRECT_INDEX],
1473 .flags = flags,
1474 };
1475 int ret;
1476
1477 alloc_inode_block(inode);
1478
1479 if (li->li_height > (__force u8)target_level)
1480 ret = __logfs_write_rec(inode, page, &wc, bix, target_level,
1481 LEVEL(li->li_height));
1482 else
1483 ret = logfs_write_i0(inode, page, &wc);
1484 if (ret)
1485 return ret;
1486
1487 if (li->li_data[INDIRECT_INDEX] != wc.ofs) {
1488 li->li_data[INDIRECT_INDEX] = wc.ofs;
1489 logfs_set_alias(inode->i_sb, li->li_block,
1490 INDIRECT_INDEX + INODE_POINTER_OFS);
1491 }
1492 return ret;
1493 }
1494
1495 void logfs_add_transaction(struct inode *inode, struct logfs_transaction *ta)
1496 {
1497 alloc_inode_block(inode);
1498 logfs_inode(inode)->li_block->ta = ta;
1499 }
1500
1501 void logfs_del_transaction(struct inode *inode, struct logfs_transaction *ta)
1502 {
1503 struct logfs_block *block = logfs_inode(inode)->li_block;
1504
1505 if (block && block->ta)
1506 block->ta = NULL;
1507 }
1508
1509 static int grow_inode(struct inode *inode, u64 bix, level_t level)
1510 {
1511 struct logfs_inode *li = logfs_inode(inode);
1512 u8 height = (__force u8)level;
1513 struct page *page;
1514 struct write_control wc = {
1515 .flags = WF_WRITE,
1516 };
1517 int err;
1518
1519 BUG_ON(height > 5 || li->li_height > 5);
1520 while (height > li->li_height || bix >= maxbix(li->li_height)) {
1521 page = logfs_get_write_page(inode, I0_BLOCKS + 1,
1522 LEVEL(li->li_height + 1));
1523 if (!page)
1524 return -ENOMEM;
1525 logfs_read_empty(page);
1526 alloc_indirect_block(inode, page, 1);
1527 block_set_pointer(page, 0, li->li_data[INDIRECT_INDEX]);
1528 err = logfs_write_i0(inode, page, &wc);
1529 logfs_put_write_page(page);
1530 if (err)
1531 return err;
1532 li->li_data[INDIRECT_INDEX] = wc.ofs;
1533 wc.ofs = 0;
1534 li->li_height++;
1535 logfs_set_alias(inode->i_sb, li->li_block, INODE_HEIGHT_OFS);
1536 }
1537 return 0;
1538 }
1539
1540 static int __logfs_write_buf(struct inode *inode, struct page *page, long flags)
1541 {
1542 struct logfs_super *super = logfs_super(inode->i_sb);
1543 pgoff_t index = page->index;
1544 u64 bix;
1545 level_t level;
1546 int err;
1547
1548 flags |= WF_WRITE | WF_DELETE;
1549 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
1550
1551 logfs_unpack_index(index, &bix, &level);
1552 if (logfs_block(page) && logfs_block(page)->reserved_bytes)
1553 super->s_dirty_pages -= logfs_block(page)->reserved_bytes;
1554
1555 if (index < I0_BLOCKS)
1556 return logfs_write_direct(inode, page, flags);
1557
1558 bix = adjust_bix(bix, level);
1559 err = grow_inode(inode, bix, level);
1560 if (err)
1561 return err;
1562 return logfs_write_rec(inode, page, bix, level, flags);
1563 }
1564
1565 int logfs_write_buf(struct inode *inode, struct page *page, long flags)
1566 {
1567 struct super_block *sb = inode->i_sb;
1568 int ret;
1569
1570 logfs_get_wblocks(sb, page, flags & WF_LOCK);
1571 ret = __logfs_write_buf(inode, page, flags);
1572 logfs_put_wblocks(sb, page, flags & WF_LOCK);
1573 return ret;
1574 }
1575
1576 static int __logfs_delete(struct inode *inode, struct page *page)
1577 {
1578 long flags = WF_DELETE;
1579 int err;
1580
1581 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
1582
1583 if (page->index < I0_BLOCKS)
1584 return logfs_write_direct(inode, page, flags);
1585 err = grow_inode(inode, page->index, 0);
1586 if (err)
1587 return err;
1588 return logfs_write_rec(inode, page, page->index, 0, flags);
1589 }
1590
1591 int logfs_delete(struct inode *inode, pgoff_t index,
1592 struct shadow_tree *shadow_tree)
1593 {
1594 struct super_block *sb = inode->i_sb;
1595 struct page *page;
1596 int ret;
1597
1598 page = logfs_get_read_page(inode, index, 0);
1599 if (!page)
1600 return -ENOMEM;
1601
1602 logfs_get_wblocks(sb, page, 1);
1603 ret = __logfs_delete(inode, page);
1604 logfs_put_wblocks(sb, page, 1);
1605
1606 logfs_put_read_page(page);
1607
1608 return ret;
1609 }
1610
1611 int logfs_rewrite_block(struct inode *inode, u64 bix, u64 ofs,
1612 gc_level_t gc_level, long flags)
1613 {
1614 level_t level = shrink_level(gc_level);
1615 struct page *page;
1616 int err;
1617
1618 page = logfs_get_write_page(inode, bix, level);
1619 if (!page)
1620 return -ENOMEM;
1621
1622 err = logfs_segment_read(inode, page, ofs, bix, level);
1623 if (!err) {
1624 if (level != 0)
1625 alloc_indirect_block(inode, page, 0);
1626 err = logfs_write_buf(inode, page, flags);
1627 if (!err && shrink_level(gc_level) == 0) {
1628 /* Rewrite cannot mark the inode dirty but has to
1629 * write it immediately.
1630 * Q: Can't we just create an alias for the inode
1631 * instead? And if not, why not?
1632 */
1633 if (inode->i_ino == LOGFS_INO_MASTER)
1634 logfs_write_anchor(inode->i_sb);
1635 else {
1636 err = __logfs_write_inode(inode, page, flags);
1637 }
1638 }
1639 }
1640 logfs_put_write_page(page);
1641 return err;
1642 }
1643
1644 static int truncate_data_block(struct inode *inode, struct page *page,
1645 u64 ofs, struct logfs_shadow *shadow, u64 size)
1646 {
1647 loff_t pageofs = page->index << inode->i_sb->s_blocksize_bits;
1648 u64 bix;
1649 level_t level;
1650 int err;
1651
1652 /* Does truncation happen within this page? */
1653 if (size <= pageofs || size - pageofs >= PAGE_SIZE)
1654 return 0;
1655
1656 logfs_unpack_index(page->index, &bix, &level);
1657 BUG_ON(level != 0);
1658
1659 err = logfs_segment_read(inode, page, ofs, bix, level);
1660 if (err)
1661 return err;
1662
1663 zero_user_segment(page, size - pageofs, PAGE_CACHE_SIZE);
1664 return logfs_segment_write(inode, page, shadow);
1665 }
1666
1667 static int logfs_truncate_i0(struct inode *inode, struct page *page,
1668 struct write_control *wc, u64 size)
1669 {
1670 struct logfs_shadow *shadow;
1671 u64 bix;
1672 level_t level;
1673 int err = 0;
1674
1675 logfs_unpack_index(page->index, &bix, &level);
1676 BUG_ON(level != 0);
1677 shadow = alloc_shadow(inode, bix, level, wc->ofs);
1678
1679 err = truncate_data_block(inode, page, wc->ofs, shadow, size);
1680 if (err) {
1681 free_shadow(inode, shadow);
1682 return err;
1683 }
1684
1685 logfs_segment_delete(inode, shadow);
1686 set_iused(inode, shadow);
1687 fill_shadow_tree(inode, page, shadow);
1688 wc->ofs = shadow->new_ofs;
1689 return 0;
1690 }
1691
1692 static int logfs_truncate_direct(struct inode *inode, u64 size)
1693 {
1694 struct logfs_inode *li = logfs_inode(inode);
1695 struct write_control wc;
1696 struct page *page;
1697 int e;
1698 int err;
1699
1700 alloc_inode_block(inode);
1701
1702 for (e = I0_BLOCKS - 1; e >= 0; e--) {
1703 if (size > (e+1) * LOGFS_BLOCKSIZE)
1704 break;
1705
1706 wc.ofs = li->li_data[e];
1707 if (!wc.ofs)
1708 continue;
1709
1710 page = logfs_get_write_page(inode, e, 0);
1711 if (!page)
1712 return -ENOMEM;
1713 err = logfs_segment_read(inode, page, wc.ofs, e, 0);
1714 if (err) {
1715 logfs_put_write_page(page);
1716 return err;
1717 }
1718 err = logfs_truncate_i0(inode, page, &wc, size);
1719 logfs_put_write_page(page);
1720 if (err)
1721 return err;
1722
1723 li->li_data[e] = wc.ofs;
1724 }
1725 return 0;
1726 }
1727
1728 /* FIXME: these need to become per-sb once we support different blocksizes */
1729 static u64 __logfs_step[] = {
1730 1,
1731 I1_BLOCKS,
1732 I2_BLOCKS,
1733 I3_BLOCKS,
1734 };
1735
1736 static u64 __logfs_start_index[] = {
1737 I0_BLOCKS,
1738 I1_BLOCKS,
1739 I2_BLOCKS,
1740 I3_BLOCKS
1741 };
1742
1743 static inline u64 logfs_step(level_t level)
1744 {
1745 return __logfs_step[(__force u8)level];
1746 }
1747
1748 static inline u64 logfs_factor(u8 level)
1749 {
1750 return __logfs_step[level] * LOGFS_BLOCKSIZE;
1751 }
1752
1753 static inline u64 logfs_start_index(level_t level)
1754 {
1755 return __logfs_start_index[(__force u8)level];
1756 }
1757
1758 static void logfs_unpack_raw_index(pgoff_t index, u64 *bix, level_t *level)
1759 {
1760 logfs_unpack_index(index, bix, level);
1761 if (*bix <= logfs_start_index(SUBLEVEL(*level)))
1762 *bix = 0;
1763 }
1764
1765 static int __logfs_truncate_rec(struct inode *inode, struct page *ipage,
1766 struct write_control *this_wc, u64 size)
1767 {
1768 int truncate_happened = 0;
1769 int e, err = 0;
1770 u64 bix, child_bix, next_bix;
1771 level_t level;
1772 struct page *page;
1773 struct write_control child_wc = { /* FIXME: flags */ };
1774
1775 logfs_unpack_raw_index(ipage->index, &bix, &level);
1776 err = logfs_segment_read(inode, ipage, this_wc->ofs, bix, level);
1777 if (err)
1778 return err;
1779
1780 for (e = LOGFS_BLOCK_FACTOR - 1; e >= 0; e--) {
1781 child_bix = bix + e * logfs_step(SUBLEVEL(level));
1782 next_bix = child_bix + logfs_step(SUBLEVEL(level));
1783 if (size > next_bix * LOGFS_BLOCKSIZE)
1784 break;
1785
1786 child_wc.ofs = pure_ofs(block_get_pointer(ipage, e));
1787 if (!child_wc.ofs)
1788 continue;
1789
1790 page = logfs_get_write_page(inode, child_bix, SUBLEVEL(level));
1791 if (!page)
1792 return -ENOMEM;
1793
1794 if ((__force u8)level > 1)
1795 err = __logfs_truncate_rec(inode, page, &child_wc, size);
1796 else
1797 err = logfs_truncate_i0(inode, page, &child_wc, size);
1798 logfs_put_write_page(page);
1799 if (err)
1800 return err;
1801
1802 truncate_happened = 1;
1803 alloc_indirect_block(inode, ipage, 0);
1804 block_set_pointer(ipage, e, child_wc.ofs);
1805 }
1806
1807 if (!truncate_happened) {
1808 printk("ineffectual truncate (%lx, %lx, %llx)\n", inode->i_ino, ipage->index, size);
1809 return 0;
1810 }
1811
1812 this_wc->flags = WF_DELETE;
1813 if (logfs_block(ipage)->partial)
1814 this_wc->flags |= WF_WRITE;
1815
1816 return logfs_write_i0(inode, ipage, this_wc);
1817 }
1818
1819 static int logfs_truncate_rec(struct inode *inode, u64 size)
1820 {
1821 struct logfs_inode *li = logfs_inode(inode);
1822 struct write_control wc = {
1823 .ofs = li->li_data[INDIRECT_INDEX],
1824 };
1825 struct page *page;
1826 int err;
1827
1828 alloc_inode_block(inode);
1829
1830 if (!wc.ofs)
1831 return 0;
1832
1833 page = logfs_get_write_page(inode, 0, LEVEL(li->li_height));
1834 if (!page)
1835 return -ENOMEM;
1836
1837 err = __logfs_truncate_rec(inode, page, &wc, size);
1838 logfs_put_write_page(page);
1839 if (err)
1840 return err;
1841
1842 if (li->li_data[INDIRECT_INDEX] != wc.ofs)
1843 li->li_data[INDIRECT_INDEX] = wc.ofs;
1844 return 0;
1845 }
1846
1847 static int __logfs_truncate(struct inode *inode, u64 size)
1848 {
1849 int ret;
1850
1851 if (size >= logfs_factor(logfs_inode(inode)->li_height))
1852 return 0;
1853
1854 ret = logfs_truncate_rec(inode, size);
1855 if (ret)
1856 return ret;
1857
1858 return logfs_truncate_direct(inode, size);
1859 }
1860
1861 /*
1862 * Truncate, by changing the segment file, can consume a fair amount
1863 * of resources. So back off from time to time and do some GC.
1864 * 8 or 2048 blocks should be well within safety limits even if
1865 * every single block resided in a different segment.
1866 */
1867 #define TRUNCATE_STEP (8 * 1024 * 1024)
1868 int logfs_truncate(struct inode *inode, u64 target)
1869 {
1870 struct super_block *sb = inode->i_sb;
1871 u64 size = i_size_read(inode);
1872 int err = 0;
1873
1874 size = ALIGN(size, TRUNCATE_STEP);
1875 while (size > target) {
1876 if (size > TRUNCATE_STEP)
1877 size -= TRUNCATE_STEP;
1878 else
1879 size = 0;
1880 if (size < target)
1881 size = target;
1882
1883 logfs_get_wblocks(sb, NULL, 1);
1884 err = __logfs_truncate(inode, size);
1885 if (!err)
1886 err = __logfs_write_inode(inode, NULL, 0);
1887 logfs_put_wblocks(sb, NULL, 1);
1888 }
1889
1890 if (!err) {
1891 err = inode_newsize_ok(inode, target);
1892 if (err)
1893 goto out;
1894
1895 truncate_setsize(inode, target);
1896 }
1897
1898 out:
1899 /* I don't trust error recovery yet. */
1900 WARN_ON(err);
1901 return err;
1902 }
1903
1904 static void move_page_to_inode(struct inode *inode, struct page *page)
1905 {
1906 struct logfs_inode *li = logfs_inode(inode);
1907 struct logfs_block *block = logfs_block(page);
1908
1909 if (!block)
1910 return;
1911
1912 log_blockmove("move_page_to_inode(%llx, %llx, %x)\n",
1913 block->ino, block->bix, block->level);
1914 BUG_ON(li->li_block);
1915 block->ops = &inode_block_ops;
1916 block->inode = inode;
1917 li->li_block = block;
1918
1919 block->page = NULL;
1920 if (PagePrivate(page)) {
1921 ClearPagePrivate(page);
1922 page_cache_release(page);
1923 set_page_private(page, 0);
1924 }
1925 }
1926
1927 static void move_inode_to_page(struct page *page, struct inode *inode)
1928 {
1929 struct logfs_inode *li = logfs_inode(inode);
1930 struct logfs_block *block = li->li_block;
1931
1932 if (!block)
1933 return;
1934
1935 log_blockmove("move_inode_to_page(%llx, %llx, %x)\n",
1936 block->ino, block->bix, block->level);
1937 BUG_ON(PagePrivate(page));
1938 block->ops = &indirect_block_ops;
1939 block->page = page;
1940
1941 if (!PagePrivate(page)) {
1942 SetPagePrivate(page);
1943 page_cache_get(page);
1944 set_page_private(page, (unsigned long) block);
1945 }
1946
1947 block->inode = NULL;
1948 li->li_block = NULL;
1949 }
1950
1951 int logfs_read_inode(struct inode *inode)
1952 {
1953 struct super_block *sb = inode->i_sb;
1954 struct logfs_super *super = logfs_super(sb);
1955 struct inode *master_inode = super->s_master_inode;
1956 struct page *page;
1957 struct logfs_disk_inode *di;
1958 u64 ino = inode->i_ino;
1959
1960 if (ino << sb->s_blocksize_bits > i_size_read(master_inode))
1961 return -ENODATA;
1962 if (!logfs_exist_block(master_inode, ino))
1963 return -ENODATA;
1964
1965 page = read_cache_page(master_inode->i_mapping, ino,
1966 (filler_t *)logfs_readpage, NULL);
1967 if (IS_ERR(page))
1968 return PTR_ERR(page);
1969
1970 di = kmap_atomic(page);
1971 logfs_disk_to_inode(di, inode);
1972 kunmap_atomic(di);
1973 move_page_to_inode(inode, page);
1974 page_cache_release(page);
1975 return 0;
1976 }
1977
1978 /* Caller must logfs_put_write_page(page); */
1979 static struct page *inode_to_page(struct inode *inode)
1980 {
1981 struct inode *master_inode = logfs_super(inode->i_sb)->s_master_inode;
1982 struct logfs_disk_inode *di;
1983 struct page *page;
1984
1985 BUG_ON(inode->i_ino == LOGFS_INO_MASTER);
1986
1987 page = logfs_get_write_page(master_inode, inode->i_ino, 0);
1988 if (!page)
1989 return NULL;
1990
1991 di = kmap_atomic(page);
1992 logfs_inode_to_disk(inode, di);
1993 kunmap_atomic(di);
1994 move_inode_to_page(page, inode);
1995 return page;
1996 }
1997
1998 static int do_write_inode(struct inode *inode)
1999 {
2000 struct super_block *sb = inode->i_sb;
2001 struct inode *master_inode = logfs_super(sb)->s_master_inode;
2002 loff_t size = (inode->i_ino + 1) << inode->i_sb->s_blocksize_bits;
2003 struct page *page;
2004 int err;
2005
2006 BUG_ON(inode->i_ino == LOGFS_INO_MASTER);
2007 /* FIXME: lock inode */
2008
2009 if (i_size_read(master_inode) < size)
2010 i_size_write(master_inode, size);
2011
2012 /* TODO: Tell vfs this inode is clean now */
2013
2014 page = inode_to_page(inode);
2015 if (!page)
2016 return -ENOMEM;
2017
2018 /* FIXME: transaction is part of logfs_block now. Is that enough? */
2019 err = logfs_write_buf(master_inode, page, 0);
2020 if (err)
2021 move_page_to_inode(inode, page);
2022
2023 logfs_put_write_page(page);
2024 return err;
2025 }
2026
2027 static void logfs_mod_segment_entry(struct super_block *sb, u32 segno,
2028 int write,
2029 void (*change_se)(struct logfs_segment_entry *, long),
2030 long arg)
2031 {
2032 struct logfs_super *super = logfs_super(sb);
2033 struct inode *inode;
2034 struct page *page;
2035 struct logfs_segment_entry *se;
2036 pgoff_t page_no;
2037 int child_no;
2038
2039 page_no = segno >> (sb->s_blocksize_bits - 3);
2040 child_no = segno & ((sb->s_blocksize >> 3) - 1);
2041
2042 inode = super->s_segfile_inode;
2043 page = logfs_get_write_page(inode, page_no, 0);
2044 BUG_ON(!page); /* FIXME: We need some reserve page for this case */
2045 if (!PageUptodate(page))
2046 logfs_read_block(inode, page, WRITE);
2047
2048 if (write)
2049 alloc_indirect_block(inode, page, 0);
2050 se = kmap_atomic(page);
2051 change_se(se + child_no, arg);
2052 if (write) {
2053 logfs_set_alias(sb, logfs_block(page), child_no);
2054 BUG_ON((int)be32_to_cpu(se[child_no].valid) > super->s_segsize);
2055 }
2056 kunmap_atomic(se);
2057
2058 logfs_put_write_page(page);
2059 }
2060
2061 static void __get_segment_entry(struct logfs_segment_entry *se, long _target)
2062 {
2063 struct logfs_segment_entry *target = (void *)_target;
2064
2065 *target = *se;
2066 }
2067
2068 void logfs_get_segment_entry(struct super_block *sb, u32 segno,
2069 struct logfs_segment_entry *se)
2070 {
2071 logfs_mod_segment_entry(sb, segno, 0, __get_segment_entry, (long)se);
2072 }
2073
2074 static void __set_segment_used(struct logfs_segment_entry *se, long increment)
2075 {
2076 u32 valid;
2077
2078 valid = be32_to_cpu(se->valid);
2079 valid += increment;
2080 se->valid = cpu_to_be32(valid);
2081 }
2082
2083 void logfs_set_segment_used(struct super_block *sb, u64 ofs, int increment)
2084 {
2085 struct logfs_super *super = logfs_super(sb);
2086 u32 segno = ofs >> super->s_segshift;
2087
2088 if (!increment)
2089 return;
2090
2091 logfs_mod_segment_entry(sb, segno, 1, __set_segment_used, increment);
2092 }
2093
2094 static void __set_segment_erased(struct logfs_segment_entry *se, long ec_level)
2095 {
2096 se->ec_level = cpu_to_be32(ec_level);
2097 }
2098
2099 void logfs_set_segment_erased(struct super_block *sb, u32 segno, u32 ec,
2100 gc_level_t gc_level)
2101 {
2102 u32 ec_level = ec << 4 | (__force u8)gc_level;
2103
2104 logfs_mod_segment_entry(sb, segno, 1, __set_segment_erased, ec_level);
2105 }
2106
2107 static void __set_segment_reserved(struct logfs_segment_entry *se, long ignore)
2108 {
2109 se->valid = cpu_to_be32(RESERVED);
2110 }
2111
2112 void logfs_set_segment_reserved(struct super_block *sb, u32 segno)
2113 {
2114 logfs_mod_segment_entry(sb, segno, 1, __set_segment_reserved, 0);
2115 }
2116
2117 static void __set_segment_unreserved(struct logfs_segment_entry *se,
2118 long ec_level)
2119 {
2120 se->valid = 0;
2121 se->ec_level = cpu_to_be32(ec_level);
2122 }
2123
2124 void logfs_set_segment_unreserved(struct super_block *sb, u32 segno, u32 ec)
2125 {
2126 u32 ec_level = ec << 4;
2127
2128 logfs_mod_segment_entry(sb, segno, 1, __set_segment_unreserved,
2129 ec_level);
2130 }
2131
2132 int __logfs_write_inode(struct inode *inode, struct page *page, long flags)
2133 {
2134 struct super_block *sb = inode->i_sb;
2135 int ret;
2136
2137 logfs_get_wblocks(sb, page, flags & WF_LOCK);
2138 ret = do_write_inode(inode);
2139 logfs_put_wblocks(sb, page, flags & WF_LOCK);
2140 return ret;
2141 }
2142
2143 static int do_delete_inode(struct inode *inode)
2144 {
2145 struct super_block *sb = inode->i_sb;
2146 struct inode *master_inode = logfs_super(sb)->s_master_inode;
2147 struct page *page;
2148 int ret;
2149
2150 page = logfs_get_write_page(master_inode, inode->i_ino, 0);
2151 if (!page)
2152 return -ENOMEM;
2153
2154 move_inode_to_page(page, inode);
2155
2156 logfs_get_wblocks(sb, page, 1);
2157 ret = __logfs_delete(master_inode, page);
2158 logfs_put_wblocks(sb, page, 1);
2159
2160 logfs_put_write_page(page);
2161 return ret;
2162 }
2163
2164 /*
2165 * ZOMBIE inodes have already been deleted before and should remain dead,
2166 * if it weren't for valid checking. No need to kill them again here.
2167 */
2168 void logfs_evict_inode(struct inode *inode)
2169 {
2170 struct super_block *sb = inode->i_sb;
2171 struct logfs_inode *li = logfs_inode(inode);
2172 struct logfs_block *block = li->li_block;
2173 struct page *page;
2174
2175 if (!inode->i_nlink) {
2176 if (!(li->li_flags & LOGFS_IF_ZOMBIE)) {
2177 li->li_flags |= LOGFS_IF_ZOMBIE;
2178 if (i_size_read(inode) > 0)
2179 logfs_truncate(inode, 0);
2180 do_delete_inode(inode);
2181 }
2182 }
2183 truncate_inode_pages(&inode->i_data, 0);
2184 clear_inode(inode);
2185
2186 /* Cheaper version of write_inode. All changes are concealed in
2187 * aliases, which are moved back. No write to the medium happens.
2188 */
2189 /* Only deleted files may be dirty at this point */
2190 BUG_ON(inode->i_state & I_DIRTY && inode->i_nlink);
2191 if (!block)
2192 return;
2193 if ((logfs_super(sb)->s_flags & LOGFS_SB_FLAG_SHUTDOWN)) {
2194 block->ops->free_block(inode->i_sb, block);
2195 return;
2196 }
2197
2198 page = inode_to_page(inode);
2199 BUG_ON(!page); /* FIXME: Use emergency page */
2200 logfs_put_write_page(page);
2201 }
2202
2203 void btree_write_block(struct logfs_block *block)
2204 {
2205 struct inode *inode;
2206 struct page *page;
2207 int err, cookie;
2208
2209 inode = logfs_safe_iget(block->sb, block->ino, &cookie);
2210 page = logfs_get_write_page(inode, block->bix, block->level);
2211
2212 err = logfs_readpage_nolock(page);
2213 BUG_ON(err);
2214 BUG_ON(!PagePrivate(page));
2215 BUG_ON(logfs_block(page) != block);
2216 err = __logfs_write_buf(inode, page, 0);
2217 BUG_ON(err);
2218 BUG_ON(PagePrivate(page) || page->private);
2219
2220 logfs_put_write_page(page);
2221 logfs_safe_iput(inode, cookie);
2222 }
2223
2224 /**
2225 * logfs_inode_write - write inode or dentry objects
2226 *
2227 * @inode: parent inode (ifile or directory)
2228 * @buf: object to write (inode or dentry)
2229 * @n: object size
2230 * @_pos: object number (file position in blocks/objects)
2231 * @flags: write flags
2232 * @lock: 0 if write lock is already taken, 1 otherwise
2233 * @shadow_tree: shadow below this inode
2234 *
2235 * FIXME: All caller of this put a 200-300 byte variable on the stack,
2236 * only to call here and do a memcpy from that stack variable. A good
2237 * example of wasted performance and stack space.
2238 */
2239 int logfs_inode_write(struct inode *inode, const void *buf, size_t count,
2240 loff_t bix, long flags, struct shadow_tree *shadow_tree)
2241 {
2242 loff_t pos = bix << inode->i_sb->s_blocksize_bits;
2243 int err;
2244 struct page *page;
2245 void *pagebuf;
2246
2247 BUG_ON(pos & (LOGFS_BLOCKSIZE-1));
2248 BUG_ON(count > LOGFS_BLOCKSIZE);
2249 page = logfs_get_write_page(inode, bix, 0);
2250 if (!page)
2251 return -ENOMEM;
2252
2253 pagebuf = kmap_atomic(page);
2254 memcpy(pagebuf, buf, count);
2255 flush_dcache_page(page);
2256 kunmap_atomic(pagebuf);
2257
2258 if (i_size_read(inode) < pos + LOGFS_BLOCKSIZE)
2259 i_size_write(inode, pos + LOGFS_BLOCKSIZE);
2260
2261 err = logfs_write_buf(inode, page, flags);
2262 logfs_put_write_page(page);
2263 return err;
2264 }
2265
2266 int logfs_open_segfile(struct super_block *sb)
2267 {
2268 struct logfs_super *super = logfs_super(sb);
2269 struct inode *inode;
2270
2271 inode = logfs_read_meta_inode(sb, LOGFS_INO_SEGFILE);
2272 if (IS_ERR(inode))
2273 return PTR_ERR(inode);
2274 super->s_segfile_inode = inode;
2275 return 0;
2276 }
2277
2278 int logfs_init_rw(struct super_block *sb)
2279 {
2280 struct logfs_super *super = logfs_super(sb);
2281 int min_fill = 3 * super->s_no_blocks;
2282
2283 INIT_LIST_HEAD(&super->s_object_alias);
2284 INIT_LIST_HEAD(&super->s_writeback_list);
2285 mutex_init(&super->s_write_mutex);
2286 super->s_block_pool = mempool_create_kmalloc_pool(min_fill,
2287 sizeof(struct logfs_block));
2288 super->s_shadow_pool = mempool_create_kmalloc_pool(min_fill,
2289 sizeof(struct logfs_shadow));
2290 return 0;
2291 }
2292
2293 void logfs_cleanup_rw(struct super_block *sb)
2294 {
2295 struct logfs_super *super = logfs_super(sb);
2296
2297 logfs_mempool_destroy(super->s_block_pool);
2298 logfs_mempool_destroy(super->s_shadow_pool);
2299 }
Linus' kernel tree