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5eb563f5
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1/*
2 * mdt.c - meta data file for NILFS
3 *
4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
4b420ab4 16 * Written by Ryusuke Konishi.
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17 */
18
19#include <linux/buffer_head.h>
20#include <linux/mpage.h>
21#include <linux/mm.h>
22#include <linux/writeback.h>
23#include <linux/backing-dev.h>
24#include <linux/swap.h>
5a0e3ad6 25#include <linux/slab.h>
5eb563f5 26#include "nilfs.h"
05d0e94b 27#include "btnode.h"
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28#include "segment.h"
29#include "page.h"
30#include "mdt.h"
2d19961d 31#include "alloc.h" /* nilfs_palloc_destroy_cache() */
5eb563f5 32
a9cd207c 33#include <trace/events/nilfs2.h>
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34
35#define NILFS_MDT_MAX_RA_BLOCKS (16 - 1)
36
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37
38static int
39nilfs_mdt_insert_new_block(struct inode *inode, unsigned long block,
40 struct buffer_head *bh,
41 void (*init_block)(struct inode *,
42 struct buffer_head *, void *))
43{
44 struct nilfs_inode_info *ii = NILFS_I(inode);
45 void *kaddr;
46 int ret;
47
48 /* Caller exclude read accesses using page lock */
49
50 /* set_buffer_new(bh); */
51 bh->b_blocknr = 0;
52
53 ret = nilfs_bmap_insert(ii->i_bmap, block, (unsigned long)bh);
54 if (unlikely(ret))
55 return ret;
56
57 set_buffer_mapped(bh);
58
7b9c0976 59 kaddr = kmap_atomic(bh->b_page);
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60 memset(kaddr + bh_offset(bh), 0, 1 << inode->i_blkbits);
61 if (init_block)
62 init_block(inode, bh, kaddr);
63 flush_dcache_page(bh->b_page);
7b9c0976 64 kunmap_atomic(kaddr);
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65
66 set_buffer_uptodate(bh);
5fc7b141 67 mark_buffer_dirty(bh);
5eb563f5 68 nilfs_mdt_mark_dirty(inode);
a9cd207c
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69
70 trace_nilfs2_mdt_insert_new_block(inode, inode->i_ino, block);
71
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72 return 0;
73}
74
75static int nilfs_mdt_create_block(struct inode *inode, unsigned long block,
76 struct buffer_head **out_bh,
77 void (*init_block)(struct inode *,
78 struct buffer_head *,
79 void *))
80{
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81 struct super_block *sb = inode->i_sb;
82 struct nilfs_transaction_info ti;
83 struct buffer_head *bh;
84 int err;
85
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86 nilfs_transaction_begin(sb, &ti, 0);
87
88 err = -ENOMEM;
89 bh = nilfs_grab_buffer(inode, inode->i_mapping, block, 0);
90 if (unlikely(!bh))
91 goto failed_unlock;
92
93 err = -EEXIST;
14351104 94 if (buffer_uptodate(bh))
5eb563f5 95 goto failed_bh;
14351104 96
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97 wait_on_buffer(bh);
98 if (buffer_uptodate(bh))
99 goto failed_bh;
5eb563f5 100
090fd5b1 101 bh->b_bdev = sb->s_bdev;
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102 err = nilfs_mdt_insert_new_block(inode, block, bh, init_block);
103 if (likely(!err)) {
104 get_bh(bh);
105 *out_bh = bh;
106 }
107
108 failed_bh:
109 unlock_page(bh->b_page);
09cbfeaf 110 put_page(bh->b_page);
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111 brelse(bh);
112
113 failed_unlock:
47420c79
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114 if (likely(!err))
115 err = nilfs_transaction_commit(sb);
116 else
117 nilfs_transaction_abort(sb);
090fd5b1 118
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119 return err;
120}
121
122static int
123nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff,
124 int mode, struct buffer_head **out_bh)
125{
126 struct buffer_head *bh;
0f3fe33b 127 __u64 blknum = 0;
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128 int ret = -ENOMEM;
129
130 bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
131 if (unlikely(!bh))
132 goto failed;
133
134 ret = -EEXIST; /* internal code */
135 if (buffer_uptodate(bh))
136 goto out;
137
138 if (mode == READA) {
139 if (!trylock_buffer(bh)) {
140 ret = -EBUSY;
141 goto failed_bh;
142 }
1f5abe7e 143 } else /* mode == READ */
5eb563f5 144 lock_buffer(bh);
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145
146 if (buffer_uptodate(bh)) {
147 unlock_buffer(bh);
148 goto out;
149 }
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150
151 ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum);
152 if (unlikely(ret)) {
153 unlock_buffer(bh);
154 goto failed_bh;
5eb563f5 155 }
c6e07188 156 map_bh(bh, inode->i_sb, (sector_t)blknum);
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157
158 bh->b_end_io = end_buffer_read_sync;
159 get_bh(bh);
160 submit_bh(mode, bh);
161 ret = 0;
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162
163 trace_nilfs2_mdt_submit_block(inode, inode->i_ino, blkoff, mode);
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164 out:
165 get_bh(bh);
166 *out_bh = bh;
167
168 failed_bh:
169 unlock_page(bh->b_page);
09cbfeaf 170 put_page(bh->b_page);
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171 brelse(bh);
172 failed:
173 return ret;
174}
175
176static int nilfs_mdt_read_block(struct inode *inode, unsigned long block,
b34a6506 177 int readahead, struct buffer_head **out_bh)
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178{
179 struct buffer_head *first_bh, *bh;
180 unsigned long blkoff;
181 int i, nr_ra_blocks = NILFS_MDT_MAX_RA_BLOCKS;
182 int err;
183
184 err = nilfs_mdt_submit_block(inode, block, READ, &first_bh);
185 if (err == -EEXIST) /* internal code */
186 goto out;
187
188 if (unlikely(err))
189 goto failed;
190
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191 if (readahead) {
192 blkoff = block + 1;
193 for (i = 0; i < nr_ra_blocks; i++, blkoff++) {
194 err = nilfs_mdt_submit_block(inode, blkoff, READA, &bh);
195 if (likely(!err || err == -EEXIST))
196 brelse(bh);
197 else if (err != -EBUSY)
198 break;
199 /* abort readahead if bmap lookup failed */
200 if (!buffer_locked(first_bh))
201 goto out_no_wait;
202 }
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203 }
204
205 wait_on_buffer(first_bh);
206
207 out_no_wait:
208 err = -EIO;
209 if (!buffer_uptodate(first_bh))
210 goto failed_bh;
211 out:
212 *out_bh = first_bh;
213 return 0;
214
215 failed_bh:
216 brelse(first_bh);
217 failed:
218 return err;
219}
220
221/**
222 * nilfs_mdt_get_block - read or create a buffer on meta data file.
223 * @inode: inode of the meta data file
224 * @blkoff: block offset
225 * @create: create flag
226 * @init_block: initializer used for newly allocated block
227 * @out_bh: output of a pointer to the buffer_head
228 *
229 * nilfs_mdt_get_block() looks up the specified buffer and tries to create
230 * a new buffer if @create is not zero. On success, the returned buffer is
231 * assured to be either existing or formatted using a buffer lock on success.
232 * @out_bh is substituted only when zero is returned.
233 *
234 * Return Value: On success, it returns 0. On error, the following negative
235 * error code is returned.
236 *
237 * %-ENOMEM - Insufficient memory available.
238 *
239 * %-EIO - I/O error
240 *
241 * %-ENOENT - the specified block does not exist (hole block)
242 *
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243 * %-EROFS - Read only filesystem (for create mode)
244 */
245int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create,
246 void (*init_block)(struct inode *,
247 struct buffer_head *, void *),
248 struct buffer_head **out_bh)
249{
250 int ret;
251
252 /* Should be rewritten with merging nilfs_mdt_read_block() */
253 retry:
b34a6506 254 ret = nilfs_mdt_read_block(inode, blkoff, !create, out_bh);
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255 if (!create || ret != -ENOENT)
256 return ret;
257
258 ret = nilfs_mdt_create_block(inode, blkoff, out_bh, init_block);
259 if (unlikely(ret == -EEXIST)) {
260 /* create = 0; */ /* limit read-create loop retries */
261 goto retry;
262 }
263 return ret;
264}
265
fa33915c
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266/**
267 * nilfs_mdt_find_block - find and get a buffer on meta data file.
268 * @inode: inode of the meta data file
269 * @start: start block offset (inclusive)
270 * @end: end block offset (inclusive)
271 * @blkoff: block offset
272 * @out_bh: place to store a pointer to buffer_head struct
273 *
274 * nilfs_mdt_find_block() looks up an existing block in range of
275 * [@start, @end] and stores pointer to a buffer head of the block to
276 * @out_bh, and block offset to @blkoff, respectively. @out_bh and
277 * @blkoff are substituted only when zero is returned.
278 *
279 * Return Value: On success, it returns 0. On error, the following negative
280 * error code is returned.
281 *
282 * %-ENOMEM - Insufficient memory available.
283 *
284 * %-EIO - I/O error
285 *
286 * %-ENOENT - no block was found in the range
287 */
288int nilfs_mdt_find_block(struct inode *inode, unsigned long start,
289 unsigned long end, unsigned long *blkoff,
290 struct buffer_head **out_bh)
291{
292 __u64 next;
293 int ret;
294
295 if (unlikely(start > end))
296 return -ENOENT;
297
298 ret = nilfs_mdt_read_block(inode, start, true, out_bh);
299 if (!ret) {
300 *blkoff = start;
301 goto out;
302 }
303 if (unlikely(ret != -ENOENT || start == ULONG_MAX))
304 goto out;
305
306 ret = nilfs_bmap_seek_key(NILFS_I(inode)->i_bmap, start + 1, &next);
307 if (!ret) {
308 if (next <= end) {
309 ret = nilfs_mdt_read_block(inode, next, true, out_bh);
310 if (!ret)
311 *blkoff = next;
312 } else {
313 ret = -ENOENT;
314 }
315 }
316out:
317 return ret;
318}
319
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320/**
321 * nilfs_mdt_delete_block - make a hole on the meta data file.
322 * @inode: inode of the meta data file
323 * @block: block offset
324 *
325 * Return Value: On success, zero is returned.
326 * On error, one of the following negative error code is returned.
327 *
328 * %-ENOMEM - Insufficient memory available.
329 *
330 * %-EIO - I/O error
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331 */
332int nilfs_mdt_delete_block(struct inode *inode, unsigned long block)
333{
334 struct nilfs_inode_info *ii = NILFS_I(inode);
335 int err;
336
337 err = nilfs_bmap_delete(ii->i_bmap, block);
84338237 338 if (!err || err == -ENOENT) {
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339 nilfs_mdt_mark_dirty(inode);
340 nilfs_mdt_forget_block(inode, block);
341 }
342 return err;
343}
344
345/**
346 * nilfs_mdt_forget_block - discard dirty state and try to remove the page
347 * @inode: inode of the meta data file
348 * @block: block offset
349 *
350 * nilfs_mdt_forget_block() clears a dirty flag of the specified buffer, and
351 * tries to release the page including the buffer from a page cache.
352 *
353 * Return Value: On success, 0 is returned. On error, one of the following
354 * negative error code is returned.
355 *
356 * %-EBUSY - page has an active buffer.
357 *
358 * %-ENOENT - page cache has no page addressed by the offset.
359 */
360int nilfs_mdt_forget_block(struct inode *inode, unsigned long block)
361{
362 pgoff_t index = (pgoff_t)block >>
09cbfeaf 363 (PAGE_SHIFT - inode->i_blkbits);
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364 struct page *page;
365 unsigned long first_block;
366 int ret = 0;
367 int still_dirty;
368
369 page = find_lock_page(inode->i_mapping, index);
370 if (!page)
371 return -ENOENT;
372
373 wait_on_page_writeback(page);
374
375 first_block = (unsigned long)index <<
09cbfeaf 376 (PAGE_SHIFT - inode->i_blkbits);
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377 if (page_has_buffers(page)) {
378 struct buffer_head *bh;
379
380 bh = nilfs_page_get_nth_block(page, block - first_block);
381 nilfs_forget_buffer(bh);
382 }
383 still_dirty = PageDirty(page);
384 unlock_page(page);
09cbfeaf 385 put_page(page);
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386
387 if (still_dirty ||
388 invalidate_inode_pages2_range(inode->i_mapping, index, index) != 0)
389 ret = -EBUSY;
390 return ret;
391}
392
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393int nilfs_mdt_fetch_dirty(struct inode *inode)
394{
395 struct nilfs_inode_info *ii = NILFS_I(inode);
396
397 if (nilfs_bmap_test_and_clear_dirty(ii->i_bmap)) {
398 set_bit(NILFS_I_DIRTY, &ii->i_state);
399 return 1;
400 }
401 return test_bit(NILFS_I_DIRTY, &ii->i_state);
402}
403
404static int
405nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
406{
8c26c4e2 407 struct inode *inode = page->mapping->host;
ebdfed4d 408 struct super_block *sb;
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409 int err = 0;
410
8c26c4e2
VD
411 if (inode && (inode->i_sb->s_flags & MS_RDONLY)) {
412 /*
413 * It means that filesystem was remounted in read-only
414 * mode because of error or metadata corruption. But we
415 * have dirty pages that try to be flushed in background.
416 * So, here we simply discard this dirty page.
417 */
418 nilfs_clear_dirty_page(page, false);
419 unlock_page(page);
420 return -EROFS;
421 }
422
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423 redirty_page_for_writepage(wbc, page);
424 unlock_page(page);
425
ebdfed4d
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426 if (!inode)
427 return 0;
428
429 sb = inode->i_sb;
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430
431 if (wbc->sync_mode == WB_SYNC_ALL)
432 err = nilfs_construct_segment(sb);
433 else if (wbc->for_reclaim)
434 nilfs_flush_segment(sb, inode->i_ino);
435
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436 return err;
437}
438
439
7f09410b 440static const struct address_space_operations def_mdt_aops = {
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441 .writepage = nilfs_mdt_write_page,
442};
443
6e1d5dcc 444static const struct inode_operations def_mdt_iops;
828c0950 445static const struct file_operations def_mdt_fops;
5eb563f5 446
5e19a995 447
f1e89c86 448int nilfs_mdt_init(struct inode *inode, gfp_t gfp_mask, size_t objsz)
5e19a995
RK
449{
450 struct nilfs_mdt_info *mi;
451
452 mi = kzalloc(max(sizeof(*mi), objsz), GFP_NOFS);
453 if (!mi)
454 return -ENOMEM;
455
5e19a995
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456 init_rwsem(&mi->mi_sem);
457 inode->i_private = mi;
458
459 inode->i_mode = S_IFREG;
460 mapping_set_gfp_mask(inode->i_mapping, gfp_mask);
f1e89c86
RK
461
462 inode->i_op = &def_mdt_iops;
463 inode->i_fop = &def_mdt_fops;
464 inode->i_mapping->a_ops = &def_mdt_aops;
5e19a995
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465
466 return 0;
467}
468
2d19961d
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469/**
470 * nilfs_mdt_clear - do cleanup for the metadata file
471 * @inode: inode of the metadata file
472 */
473void nilfs_mdt_clear(struct inode *inode)
474{
475 struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
476
477 if (mdi->mi_palloc_cache)
478 nilfs_palloc_destroy_cache(inode);
479}
480
481/**
482 * nilfs_mdt_destroy - release resources used by the metadata file
483 * @inode: inode of the metadata file
484 */
485void nilfs_mdt_destroy(struct inode *inode)
486{
487 struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
488
489 kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
490 kfree(mdi);
491}
492
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493void nilfs_mdt_set_entry_size(struct inode *inode, unsigned entry_size,
494 unsigned header_size)
495{
496 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
497
498 mi->mi_entry_size = entry_size;
499 mi->mi_entries_per_block = (1 << inode->i_blkbits) / entry_size;
500 mi->mi_first_entry_offset = DIV_ROUND_UP(header_size, entry_size);
501}
502
ebdfed4d
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503/**
504 * nilfs_mdt_setup_shadow_map - setup shadow map and bind it to metadata file
505 * @inode: inode of the metadata file
506 * @shadow: shadow mapping
507 */
508int nilfs_mdt_setup_shadow_map(struct inode *inode,
509 struct nilfs_shadow_map *shadow)
510{
511 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
ebdfed4d
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512
513 INIT_LIST_HEAD(&shadow->frozen_buffers);
2aa15890 514 address_space_init_once(&shadow->frozen_data);
b83ae6d4 515 nilfs_mapping_init(&shadow->frozen_data, inode);
2aa15890 516 address_space_init_once(&shadow->frozen_btnodes);
b83ae6d4 517 nilfs_mapping_init(&shadow->frozen_btnodes, inode);
ebdfed4d
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518 mi->mi_shadow = shadow;
519 return 0;
520}
521
522/**
523 * nilfs_mdt_save_to_shadow_map - copy bmap and dirty pages to shadow map
524 * @inode: inode of the metadata file
525 */
526int nilfs_mdt_save_to_shadow_map(struct inode *inode)
527{
528 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
529 struct nilfs_inode_info *ii = NILFS_I(inode);
530 struct nilfs_shadow_map *shadow = mi->mi_shadow;
531 int ret;
532
533 ret = nilfs_copy_dirty_pages(&shadow->frozen_data, inode->i_mapping);
534 if (ret)
535 goto out;
536
537 ret = nilfs_copy_dirty_pages(&shadow->frozen_btnodes,
538 &ii->i_btnode_cache);
539 if (ret)
540 goto out;
541
542 nilfs_bmap_save(ii->i_bmap, &shadow->bmap_store);
543 out:
544 return ret;
545}
546
b1f6a4f2
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547int nilfs_mdt_freeze_buffer(struct inode *inode, struct buffer_head *bh)
548{
549 struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
550 struct buffer_head *bh_frozen;
551 struct page *page;
552 int blkbits = inode->i_blkbits;
b1f6a4f2
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553
554 page = grab_cache_page(&shadow->frozen_data, bh->b_page->index);
555 if (!page)
a7a8447e 556 return -ENOMEM;
b1f6a4f2
RK
557
558 if (!page_has_buffers(page))
559 create_empty_buffers(page, 1 << blkbits, 0);
560
561 bh_frozen = nilfs_page_get_nth_block(page, bh_offset(bh) >> blkbits);
a7a8447e
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562
563 if (!buffer_uptodate(bh_frozen))
564 nilfs_copy_buffer(bh_frozen, bh);
565 if (list_empty(&bh_frozen->b_assoc_buffers)) {
566 list_add_tail(&bh_frozen->b_assoc_buffers,
567 &shadow->frozen_buffers);
568 set_buffer_nilfs_redirected(bh);
569 } else {
570 brelse(bh_frozen); /* already frozen */
b1f6a4f2 571 }
a7a8447e 572
b1f6a4f2 573 unlock_page(page);
09cbfeaf 574 put_page(page);
a7a8447e 575 return 0;
b1f6a4f2
RK
576}
577
578struct buffer_head *
579nilfs_mdt_get_frozen_buffer(struct inode *inode, struct buffer_head *bh)
580{
581 struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
582 struct buffer_head *bh_frozen = NULL;
583 struct page *page;
584 int n;
585
586 page = find_lock_page(&shadow->frozen_data, bh->b_page->index);
587 if (page) {
588 if (page_has_buffers(page)) {
589 n = bh_offset(bh) >> inode->i_blkbits;
590 bh_frozen = nilfs_page_get_nth_block(page, n);
591 }
592 unlock_page(page);
09cbfeaf 593 put_page(page);
b1f6a4f2
RK
594 }
595 return bh_frozen;
596}
597
598static void nilfs_release_frozen_buffers(struct nilfs_shadow_map *shadow)
599{
600 struct list_head *head = &shadow->frozen_buffers;
601 struct buffer_head *bh;
602
603 while (!list_empty(head)) {
604 bh = list_first_entry(head, struct buffer_head,
605 b_assoc_buffers);
606 list_del_init(&bh->b_assoc_buffers);
607 brelse(bh); /* drop ref-count to make it releasable */
608 }
609}
610
ebdfed4d
RK
611/**
612 * nilfs_mdt_restore_from_shadow_map - restore dirty pages and bmap state
613 * @inode: inode of the metadata file
614 */
615void nilfs_mdt_restore_from_shadow_map(struct inode *inode)
616{
617 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
618 struct nilfs_inode_info *ii = NILFS_I(inode);
619 struct nilfs_shadow_map *shadow = mi->mi_shadow;
620
621 down_write(&mi->mi_sem);
622
623 if (mi->mi_palloc_cache)
624 nilfs_palloc_clear_cache(inode);
625
8c26c4e2 626 nilfs_clear_dirty_pages(inode->i_mapping, true);
ebdfed4d
RK
627 nilfs_copy_back_pages(inode->i_mapping, &shadow->frozen_data);
628
8c26c4e2 629 nilfs_clear_dirty_pages(&ii->i_btnode_cache, true);
ebdfed4d
RK
630 nilfs_copy_back_pages(&ii->i_btnode_cache, &shadow->frozen_btnodes);
631
632 nilfs_bmap_restore(ii->i_bmap, &shadow->bmap_store);
633
634 up_write(&mi->mi_sem);
635}
636
637/**
638 * nilfs_mdt_clear_shadow_map - truncate pages in shadow map caches
639 * @inode: inode of the metadata file
640 */
641void nilfs_mdt_clear_shadow_map(struct inode *inode)
642{
643 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
644 struct nilfs_shadow_map *shadow = mi->mi_shadow;
645
646 down_write(&mi->mi_sem);
b1f6a4f2 647 nilfs_release_frozen_buffers(shadow);
ebdfed4d
RK
648 truncate_inode_pages(&shadow->frozen_data, 0);
649 truncate_inode_pages(&shadow->frozen_btnodes, 0);
650 up_write(&mi->mi_sem);
651}