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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 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 *
20 * Written by Ryusuke Konishi <ryusuke@osrg.net>
21 */
22
23#include <linux/buffer_head.h>
24#include <linux/mpage.h>
25#include <linux/mm.h>
26#include <linux/writeback.h>
27#include <linux/backing-dev.h>
28#include <linux/swap.h>
29#include <linux/slab.h>
30#include "nilfs.h"
31#include "btnode.h"
32#include "segment.h"
33#include "page.h"
34#include "mdt.h"
35
36
37#define NILFS_MDT_MAX_RA_BLOCKS (16 - 1)
38
39
40static int
41nilfs_mdt_insert_new_block(struct inode *inode, unsigned long block,
42 struct buffer_head *bh,
43 void (*init_block)(struct inode *,
44 struct buffer_head *, void *))
45{
46 struct nilfs_inode_info *ii = NILFS_I(inode);
47 void *kaddr;
48 int ret;
49
50 /* Caller exclude read accesses using page lock */
51
52 /* set_buffer_new(bh); */
53 bh->b_blocknr = 0;
54
55 ret = nilfs_bmap_insert(ii->i_bmap, block, (unsigned long)bh);
56 if (unlikely(ret))
57 return ret;
58
59 set_buffer_mapped(bh);
60
61 kaddr = kmap_atomic(bh->b_page);
62 memset(kaddr + bh_offset(bh), 0, 1 << inode->i_blkbits);
63 if (init_block)
64 init_block(inode, bh, kaddr);
65 flush_dcache_page(bh->b_page);
66 kunmap_atomic(kaddr);
67
68 set_buffer_uptodate(bh);
69 mark_buffer_dirty(bh);
70 nilfs_mdt_mark_dirty(inode);
71 return 0;
72}
73
74static int nilfs_mdt_create_block(struct inode *inode, unsigned long block,
75 struct buffer_head **out_bh,
76 void (*init_block)(struct inode *,
77 struct buffer_head *,
78 void *))
79{
80 struct super_block *sb = inode->i_sb;
81 struct nilfs_transaction_info ti;
82 struct buffer_head *bh;
83 int err;
84
85 nilfs_transaction_begin(sb, &ti, 0);
86
87 err = -ENOMEM;
88 bh = nilfs_grab_buffer(inode, inode->i_mapping, block, 0);
89 if (unlikely(!bh))
90 goto failed_unlock;
91
92 err = -EEXIST;
93 if (buffer_uptodate(bh))
94 goto failed_bh;
95
96 wait_on_buffer(bh);
97 if (buffer_uptodate(bh))
98 goto failed_bh;
99
100 bh->b_bdev = sb->s_bdev;
101 err = nilfs_mdt_insert_new_block(inode, block, bh, init_block);
102 if (likely(!err)) {
103 get_bh(bh);
104 *out_bh = bh;
105 }
106
107 failed_bh:
108 unlock_page(bh->b_page);
109 page_cache_release(bh->b_page);
110 brelse(bh);
111
112 failed_unlock:
113 if (likely(!err))
114 err = nilfs_transaction_commit(sb);
115 else
116 nilfs_transaction_abort(sb);
117
118 return err;
119}
120
121static int
122nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff,
123 int mode, struct buffer_head **out_bh)
124{
125 struct buffer_head *bh;
126 __u64 blknum = 0;
127 int ret = -ENOMEM;
128
129 bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
130 if (unlikely(!bh))
131 goto failed;
132
133 ret = -EEXIST; /* internal code */
134 if (buffer_uptodate(bh))
135 goto out;
136
137 if (mode == READA) {
138 if (!trylock_buffer(bh)) {
139 ret = -EBUSY;
140 goto failed_bh;
141 }
142 } else /* mode == READ */
143 lock_buffer(bh);
144
145 if (buffer_uptodate(bh)) {
146 unlock_buffer(bh);
147 goto out;
148 }
149
150 ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum);
151 if (unlikely(ret)) {
152 unlock_buffer(bh);
153 goto failed_bh;
154 }
155 map_bh(bh, inode->i_sb, (sector_t)blknum);
156
157 bh->b_end_io = end_buffer_read_sync;
158 get_bh(bh);
159 submit_bh(mode, bh);
160 ret = 0;
161 out:
162 get_bh(bh);
163 *out_bh = bh;
164
165 failed_bh:
166 unlock_page(bh->b_page);
167 page_cache_release(bh->b_page);
168 brelse(bh);
169 failed:
170 return ret;
171}
172
173static int nilfs_mdt_read_block(struct inode *inode, unsigned long block,
174 int readahead, struct buffer_head **out_bh)
175{
176 struct buffer_head *first_bh, *bh;
177 unsigned long blkoff;
178 int i, nr_ra_blocks = NILFS_MDT_MAX_RA_BLOCKS;
179 int err;
180
181 err = nilfs_mdt_submit_block(inode, block, READ, &first_bh);
182 if (err == -EEXIST) /* internal code */
183 goto out;
184
185 if (unlikely(err))
186 goto failed;
187
188 if (readahead) {
189 blkoff = block + 1;
190 for (i = 0; i < nr_ra_blocks; i++, blkoff++) {
191 err = nilfs_mdt_submit_block(inode, blkoff, READA, &bh);
192 if (likely(!err || err == -EEXIST))
193 brelse(bh);
194 else if (err != -EBUSY)
195 break;
196 /* abort readahead if bmap lookup failed */
197 if (!buffer_locked(first_bh))
198 goto out_no_wait;
199 }
200 }
201
202 wait_on_buffer(first_bh);
203
204 out_no_wait:
205 err = -EIO;
206 if (!buffer_uptodate(first_bh))
207 goto failed_bh;
208 out:
209 *out_bh = first_bh;
210 return 0;
211
212 failed_bh:
213 brelse(first_bh);
214 failed:
215 return err;
216}
217
218/**
219 * nilfs_mdt_get_block - read or create a buffer on meta data file.
220 * @inode: inode of the meta data file
221 * @blkoff: block offset
222 * @create: create flag
223 * @init_block: initializer used for newly allocated block
224 * @out_bh: output of a pointer to the buffer_head
225 *
226 * nilfs_mdt_get_block() looks up the specified buffer and tries to create
227 * a new buffer if @create is not zero. On success, the returned buffer is
228 * assured to be either existing or formatted using a buffer lock on success.
229 * @out_bh is substituted only when zero is returned.
230 *
231 * Return Value: On success, it returns 0. On error, the following negative
232 * error code is returned.
233 *
234 * %-ENOMEM - Insufficient memory available.
235 *
236 * %-EIO - I/O error
237 *
238 * %-ENOENT - the specified block does not exist (hole block)
239 *
240 * %-EROFS - Read only filesystem (for create mode)
241 */
242int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create,
243 void (*init_block)(struct inode *,
244 struct buffer_head *, void *),
245 struct buffer_head **out_bh)
246{
247 int ret;
248
249 /* Should be rewritten with merging nilfs_mdt_read_block() */
250 retry:
251 ret = nilfs_mdt_read_block(inode, blkoff, !create, out_bh);
252 if (!create || ret != -ENOENT)
253 return ret;
254
255 ret = nilfs_mdt_create_block(inode, blkoff, out_bh, init_block);
256 if (unlikely(ret == -EEXIST)) {
257 /* create = 0; */ /* limit read-create loop retries */
258 goto retry;
259 }
260 return ret;
261}
262
263/**
264 * nilfs_mdt_delete_block - make a hole on the meta data file.
265 * @inode: inode of the meta data file
266 * @block: block offset
267 *
268 * Return Value: On success, zero is returned.
269 * On error, one of the following negative error code is returned.
270 *
271 * %-ENOMEM - Insufficient memory available.
272 *
273 * %-EIO - I/O error
274 */
275int nilfs_mdt_delete_block(struct inode *inode, unsigned long block)
276{
277 struct nilfs_inode_info *ii = NILFS_I(inode);
278 int err;
279
280 err = nilfs_bmap_delete(ii->i_bmap, block);
281 if (!err || err == -ENOENT) {
282 nilfs_mdt_mark_dirty(inode);
283 nilfs_mdt_forget_block(inode, block);
284 }
285 return err;
286}
287
288/**
289 * nilfs_mdt_forget_block - discard dirty state and try to remove the page
290 * @inode: inode of the meta data file
291 * @block: block offset
292 *
293 * nilfs_mdt_forget_block() clears a dirty flag of the specified buffer, and
294 * tries to release the page including the buffer from a page cache.
295 *
296 * Return Value: On success, 0 is returned. On error, one of the following
297 * negative error code is returned.
298 *
299 * %-EBUSY - page has an active buffer.
300 *
301 * %-ENOENT - page cache has no page addressed by the offset.
302 */
303int nilfs_mdt_forget_block(struct inode *inode, unsigned long block)
304{
305 pgoff_t index = (pgoff_t)block >>
306 (PAGE_CACHE_SHIFT - inode->i_blkbits);
307 struct page *page;
308 unsigned long first_block;
309 int ret = 0;
310 int still_dirty;
311
312 page = find_lock_page(inode->i_mapping, index);
313 if (!page)
314 return -ENOENT;
315
316 wait_on_page_writeback(page);
317
318 first_block = (unsigned long)index <<
319 (PAGE_CACHE_SHIFT - inode->i_blkbits);
320 if (page_has_buffers(page)) {
321 struct buffer_head *bh;
322
323 bh = nilfs_page_get_nth_block(page, block - first_block);
324 nilfs_forget_buffer(bh);
325 }
326 still_dirty = PageDirty(page);
327 unlock_page(page);
328 page_cache_release(page);
329
330 if (still_dirty ||
331 invalidate_inode_pages2_range(inode->i_mapping, index, index) != 0)
332 ret = -EBUSY;
333 return ret;
334}
335
336/**
337 * nilfs_mdt_mark_block_dirty - mark a block on the meta data file dirty.
338 * @inode: inode of the meta data file
339 * @block: block offset
340 *
341 * Return Value: On success, it returns 0. On error, the following negative
342 * error code is returned.
343 *
344 * %-ENOMEM - Insufficient memory available.
345 *
346 * %-EIO - I/O error
347 *
348 * %-ENOENT - the specified block does not exist (hole block)
349 */
350int nilfs_mdt_mark_block_dirty(struct inode *inode, unsigned long block)
351{
352 struct buffer_head *bh;
353 int err;
354
355 err = nilfs_mdt_read_block(inode, block, 0, &bh);
356 if (unlikely(err))
357 return err;
358 mark_buffer_dirty(bh);
359 nilfs_mdt_mark_dirty(inode);
360 brelse(bh);
361 return 0;
362}
363
364int nilfs_mdt_fetch_dirty(struct inode *inode)
365{
366 struct nilfs_inode_info *ii = NILFS_I(inode);
367
368 if (nilfs_bmap_test_and_clear_dirty(ii->i_bmap)) {
369 set_bit(NILFS_I_DIRTY, &ii->i_state);
370 return 1;
371 }
372 return test_bit(NILFS_I_DIRTY, &ii->i_state);
373}
374
375static int
376nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
377{
378 struct inode *inode;
379 struct super_block *sb;
380 int err = 0;
381
382 redirty_page_for_writepage(wbc, page);
383 unlock_page(page);
384
385 inode = page->mapping->host;
386 if (!inode)
387 return 0;
388
389 sb = inode->i_sb;
390
391 if (wbc->sync_mode == WB_SYNC_ALL)
392 err = nilfs_construct_segment(sb);
393 else if (wbc->for_reclaim)
394 nilfs_flush_segment(sb, inode->i_ino);
395
396 return err;
397}
398
399
400static const struct address_space_operations def_mdt_aops = {
401 .writepage = nilfs_mdt_write_page,
402};
403
404static const struct inode_operations def_mdt_iops;
405static const struct file_operations def_mdt_fops;
406
407
408int nilfs_mdt_init(struct inode *inode, gfp_t gfp_mask, size_t objsz)
409{
410 struct nilfs_mdt_info *mi;
411
412 mi = kzalloc(max(sizeof(*mi), objsz), GFP_NOFS);
413 if (!mi)
414 return -ENOMEM;
415
416 init_rwsem(&mi->mi_sem);
417 inode->i_private = mi;
418
419 inode->i_mode = S_IFREG;
420 mapping_set_gfp_mask(inode->i_mapping, gfp_mask);
421 inode->i_mapping->backing_dev_info = inode->i_sb->s_bdi;
422
423 inode->i_op = &def_mdt_iops;
424 inode->i_fop = &def_mdt_fops;
425 inode->i_mapping->a_ops = &def_mdt_aops;
426
427 return 0;
428}
429
430void nilfs_mdt_set_entry_size(struct inode *inode, unsigned entry_size,
431 unsigned header_size)
432{
433 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
434
435 mi->mi_entry_size = entry_size;
436 mi->mi_entries_per_block = (1 << inode->i_blkbits) / entry_size;
437 mi->mi_first_entry_offset = DIV_ROUND_UP(header_size, entry_size);
438}
439
440/**
441 * nilfs_mdt_setup_shadow_map - setup shadow map and bind it to metadata file
442 * @inode: inode of the metadata file
443 * @shadow: shadow mapping
444 */
445int nilfs_mdt_setup_shadow_map(struct inode *inode,
446 struct nilfs_shadow_map *shadow)
447{
448 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
449 struct backing_dev_info *bdi = inode->i_sb->s_bdi;
450
451 INIT_LIST_HEAD(&shadow->frozen_buffers);
452 address_space_init_once(&shadow->frozen_data);
453 nilfs_mapping_init(&shadow->frozen_data, inode, bdi);
454 address_space_init_once(&shadow->frozen_btnodes);
455 nilfs_mapping_init(&shadow->frozen_btnodes, inode, bdi);
456 mi->mi_shadow = shadow;
457 return 0;
458}
459
460/**
461 * nilfs_mdt_save_to_shadow_map - copy bmap and dirty pages to shadow map
462 * @inode: inode of the metadata file
463 */
464int nilfs_mdt_save_to_shadow_map(struct inode *inode)
465{
466 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
467 struct nilfs_inode_info *ii = NILFS_I(inode);
468 struct nilfs_shadow_map *shadow = mi->mi_shadow;
469 int ret;
470
471 ret = nilfs_copy_dirty_pages(&shadow->frozen_data, inode->i_mapping);
472 if (ret)
473 goto out;
474
475 ret = nilfs_copy_dirty_pages(&shadow->frozen_btnodes,
476 &ii->i_btnode_cache);
477 if (ret)
478 goto out;
479
480 nilfs_bmap_save(ii->i_bmap, &shadow->bmap_store);
481 out:
482 return ret;
483}
484
485int nilfs_mdt_freeze_buffer(struct inode *inode, struct buffer_head *bh)
486{
487 struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
488 struct buffer_head *bh_frozen;
489 struct page *page;
490 int blkbits = inode->i_blkbits;
491
492 page = grab_cache_page(&shadow->frozen_data, bh->b_page->index);
493 if (!page)
494 return -ENOMEM;
495
496 if (!page_has_buffers(page))
497 create_empty_buffers(page, 1 << blkbits, 0);
498
499 bh_frozen = nilfs_page_get_nth_block(page, bh_offset(bh) >> blkbits);
500
501 if (!buffer_uptodate(bh_frozen))
502 nilfs_copy_buffer(bh_frozen, bh);
503 if (list_empty(&bh_frozen->b_assoc_buffers)) {
504 list_add_tail(&bh_frozen->b_assoc_buffers,
505 &shadow->frozen_buffers);
506 set_buffer_nilfs_redirected(bh);
507 } else {
508 brelse(bh_frozen); /* already frozen */
509 }
510
511 unlock_page(page);
512 page_cache_release(page);
513 return 0;
514}
515
516struct buffer_head *
517nilfs_mdt_get_frozen_buffer(struct inode *inode, struct buffer_head *bh)
518{
519 struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
520 struct buffer_head *bh_frozen = NULL;
521 struct page *page;
522 int n;
523
524 page = find_lock_page(&shadow->frozen_data, bh->b_page->index);
525 if (page) {
526 if (page_has_buffers(page)) {
527 n = bh_offset(bh) >> inode->i_blkbits;
528 bh_frozen = nilfs_page_get_nth_block(page, n);
529 }
530 unlock_page(page);
531 page_cache_release(page);
532 }
533 return bh_frozen;
534}
535
536static void nilfs_release_frozen_buffers(struct nilfs_shadow_map *shadow)
537{
538 struct list_head *head = &shadow->frozen_buffers;
539 struct buffer_head *bh;
540
541 while (!list_empty(head)) {
542 bh = list_first_entry(head, struct buffer_head,
543 b_assoc_buffers);
544 list_del_init(&bh->b_assoc_buffers);
545 brelse(bh); /* drop ref-count to make it releasable */
546 }
547}
548
549/**
550 * nilfs_mdt_restore_from_shadow_map - restore dirty pages and bmap state
551 * @inode: inode of the metadata file
552 */
553void nilfs_mdt_restore_from_shadow_map(struct inode *inode)
554{
555 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
556 struct nilfs_inode_info *ii = NILFS_I(inode);
557 struct nilfs_shadow_map *shadow = mi->mi_shadow;
558
559 down_write(&mi->mi_sem);
560
561 if (mi->mi_palloc_cache)
562 nilfs_palloc_clear_cache(inode);
563
564 nilfs_clear_dirty_pages(inode->i_mapping);
565 nilfs_copy_back_pages(inode->i_mapping, &shadow->frozen_data);
566
567 nilfs_clear_dirty_pages(&ii->i_btnode_cache);
568 nilfs_copy_back_pages(&ii->i_btnode_cache, &shadow->frozen_btnodes);
569
570 nilfs_bmap_restore(ii->i_bmap, &shadow->bmap_store);
571
572 up_write(&mi->mi_sem);
573}
574
575/**
576 * nilfs_mdt_clear_shadow_map - truncate pages in shadow map caches
577 * @inode: inode of the metadata file
578 */
579void nilfs_mdt_clear_shadow_map(struct inode *inode)
580{
581 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
582 struct nilfs_shadow_map *shadow = mi->mi_shadow;
583
584 down_write(&mi->mi_sem);
585 nilfs_release_frozen_buffers(shadow);
586 truncate_inode_pages(&shadow->frozen_data, 0);
587 truncate_inode_pages(&shadow->frozen_btnodes, 0);
588 up_write(&mi->mi_sem);
589}
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * mdt.c - meta data file for NILFS
4 *
5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6 *
7 * Written by Ryusuke Konishi.
8 */
9
10#include <linux/buffer_head.h>
11#include <linux/mpage.h>
12#include <linux/mm.h>
13#include <linux/writeback.h>
14#include <linux/backing-dev.h>
15#include <linux/swap.h>
16#include <linux/slab.h>
17#include "nilfs.h"
18#include "btnode.h"
19#include "segment.h"
20#include "page.h"
21#include "mdt.h"
22#include "alloc.h" /* nilfs_palloc_destroy_cache() */
23
24#include <trace/events/nilfs2.h>
25
26#define NILFS_MDT_MAX_RA_BLOCKS (16 - 1)
27
28
29static int
30nilfs_mdt_insert_new_block(struct inode *inode, unsigned long block,
31 struct buffer_head *bh,
32 void (*init_block)(struct inode *,
33 struct buffer_head *, void *))
34{
35 struct nilfs_inode_info *ii = NILFS_I(inode);
36 void *kaddr;
37 int ret;
38
39 /* Caller exclude read accesses using page lock */
40
41 /* set_buffer_new(bh); */
42 bh->b_blocknr = 0;
43
44 ret = nilfs_bmap_insert(ii->i_bmap, block, (unsigned long)bh);
45 if (unlikely(ret))
46 return ret;
47
48 set_buffer_mapped(bh);
49
50 kaddr = kmap_atomic(bh->b_page);
51 memset(kaddr + bh_offset(bh), 0, i_blocksize(inode));
52 if (init_block)
53 init_block(inode, bh, kaddr);
54 flush_dcache_page(bh->b_page);
55 kunmap_atomic(kaddr);
56
57 set_buffer_uptodate(bh);
58 mark_buffer_dirty(bh);
59 nilfs_mdt_mark_dirty(inode);
60
61 trace_nilfs2_mdt_insert_new_block(inode, inode->i_ino, block);
62
63 return 0;
64}
65
66static int nilfs_mdt_create_block(struct inode *inode, unsigned long block,
67 struct buffer_head **out_bh,
68 void (*init_block)(struct inode *,
69 struct buffer_head *,
70 void *))
71{
72 struct super_block *sb = inode->i_sb;
73 struct nilfs_transaction_info ti;
74 struct buffer_head *bh;
75 int err;
76
77 nilfs_transaction_begin(sb, &ti, 0);
78
79 err = -ENOMEM;
80 bh = nilfs_grab_buffer(inode, inode->i_mapping, block, 0);
81 if (unlikely(!bh))
82 goto failed_unlock;
83
84 err = -EEXIST;
85 if (buffer_uptodate(bh))
86 goto failed_bh;
87
88 wait_on_buffer(bh);
89 if (buffer_uptodate(bh))
90 goto failed_bh;
91
92 bh->b_bdev = sb->s_bdev;
93 err = nilfs_mdt_insert_new_block(inode, block, bh, init_block);
94 if (likely(!err)) {
95 get_bh(bh);
96 *out_bh = bh;
97 }
98
99 failed_bh:
100 unlock_page(bh->b_page);
101 put_page(bh->b_page);
102 brelse(bh);
103
104 failed_unlock:
105 if (likely(!err))
106 err = nilfs_transaction_commit(sb);
107 else
108 nilfs_transaction_abort(sb);
109
110 return err;
111}
112
113static int
114nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff,
115 int mode, int mode_flags, struct buffer_head **out_bh)
116{
117 struct buffer_head *bh;
118 __u64 blknum = 0;
119 int ret = -ENOMEM;
120
121 bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
122 if (unlikely(!bh))
123 goto failed;
124
125 ret = -EEXIST; /* internal code */
126 if (buffer_uptodate(bh))
127 goto out;
128
129 if (mode_flags & REQ_RAHEAD) {
130 if (!trylock_buffer(bh)) {
131 ret = -EBUSY;
132 goto failed_bh;
133 }
134 } else /* mode == READ */
135 lock_buffer(bh);
136
137 if (buffer_uptodate(bh)) {
138 unlock_buffer(bh);
139 goto out;
140 }
141
142 ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum);
143 if (unlikely(ret)) {
144 unlock_buffer(bh);
145 goto failed_bh;
146 }
147 map_bh(bh, inode->i_sb, (sector_t)blknum);
148
149 bh->b_end_io = end_buffer_read_sync;
150 get_bh(bh);
151 submit_bh(mode, mode_flags, bh);
152 ret = 0;
153
154 trace_nilfs2_mdt_submit_block(inode, inode->i_ino, blkoff, mode);
155 out:
156 get_bh(bh);
157 *out_bh = bh;
158
159 failed_bh:
160 unlock_page(bh->b_page);
161 put_page(bh->b_page);
162 brelse(bh);
163 failed:
164 return ret;
165}
166
167static int nilfs_mdt_read_block(struct inode *inode, unsigned long block,
168 int readahead, struct buffer_head **out_bh)
169{
170 struct buffer_head *first_bh, *bh;
171 unsigned long blkoff;
172 int i, nr_ra_blocks = NILFS_MDT_MAX_RA_BLOCKS;
173 int err;
174
175 err = nilfs_mdt_submit_block(inode, block, REQ_OP_READ, 0, &first_bh);
176 if (err == -EEXIST) /* internal code */
177 goto out;
178
179 if (unlikely(err))
180 goto failed;
181
182 if (readahead) {
183 blkoff = block + 1;
184 for (i = 0; i < nr_ra_blocks; i++, blkoff++) {
185 err = nilfs_mdt_submit_block(inode, blkoff, REQ_OP_READ,
186 REQ_RAHEAD, &bh);
187 if (likely(!err || err == -EEXIST))
188 brelse(bh);
189 else if (err != -EBUSY)
190 break;
191 /* abort readahead if bmap lookup failed */
192 if (!buffer_locked(first_bh))
193 goto out_no_wait;
194 }
195 }
196
197 wait_on_buffer(first_bh);
198
199 out_no_wait:
200 err = -EIO;
201 if (!buffer_uptodate(first_bh)) {
202 nilfs_err(inode->i_sb,
203 "I/O error reading meta-data file (ino=%lu, block-offset=%lu)",
204 inode->i_ino, block);
205 goto failed_bh;
206 }
207 out:
208 *out_bh = first_bh;
209 return 0;
210
211 failed_bh:
212 brelse(first_bh);
213 failed:
214 return err;
215}
216
217/**
218 * nilfs_mdt_get_block - read or create a buffer on meta data file.
219 * @inode: inode of the meta data file
220 * @blkoff: block offset
221 * @create: create flag
222 * @init_block: initializer used for newly allocated block
223 * @out_bh: output of a pointer to the buffer_head
224 *
225 * nilfs_mdt_get_block() looks up the specified buffer and tries to create
226 * a new buffer if @create is not zero. On success, the returned buffer is
227 * assured to be either existing or formatted using a buffer lock on success.
228 * @out_bh is substituted only when zero is returned.
229 *
230 * Return Value: On success, it returns 0. On error, the following negative
231 * error code is returned.
232 *
233 * %-ENOMEM - Insufficient memory available.
234 *
235 * %-EIO - I/O error
236 *
237 * %-ENOENT - the specified block does not exist (hole block)
238 *
239 * %-EROFS - Read only filesystem (for create mode)
240 */
241int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create,
242 void (*init_block)(struct inode *,
243 struct buffer_head *, void *),
244 struct buffer_head **out_bh)
245{
246 int ret;
247
248 /* Should be rewritten with merging nilfs_mdt_read_block() */
249 retry:
250 ret = nilfs_mdt_read_block(inode, blkoff, !create, out_bh);
251 if (!create || ret != -ENOENT)
252 return ret;
253
254 ret = nilfs_mdt_create_block(inode, blkoff, out_bh, init_block);
255 if (unlikely(ret == -EEXIST)) {
256 /* create = 0; */ /* limit read-create loop retries */
257 goto retry;
258 }
259 return ret;
260}
261
262/**
263 * nilfs_mdt_find_block - find and get a buffer on meta data file.
264 * @inode: inode of the meta data file
265 * @start: start block offset (inclusive)
266 * @end: end block offset (inclusive)
267 * @blkoff: block offset
268 * @out_bh: place to store a pointer to buffer_head struct
269 *
270 * nilfs_mdt_find_block() looks up an existing block in range of
271 * [@start, @end] and stores pointer to a buffer head of the block to
272 * @out_bh, and block offset to @blkoff, respectively. @out_bh and
273 * @blkoff are substituted only when zero is returned.
274 *
275 * Return Value: On success, it returns 0. On error, the following negative
276 * error code is returned.
277 *
278 * %-ENOMEM - Insufficient memory available.
279 *
280 * %-EIO - I/O error
281 *
282 * %-ENOENT - no block was found in the range
283 */
284int nilfs_mdt_find_block(struct inode *inode, unsigned long start,
285 unsigned long end, unsigned long *blkoff,
286 struct buffer_head **out_bh)
287{
288 __u64 next;
289 int ret;
290
291 if (unlikely(start > end))
292 return -ENOENT;
293
294 ret = nilfs_mdt_read_block(inode, start, true, out_bh);
295 if (!ret) {
296 *blkoff = start;
297 goto out;
298 }
299 if (unlikely(ret != -ENOENT || start == ULONG_MAX))
300 goto out;
301
302 ret = nilfs_bmap_seek_key(NILFS_I(inode)->i_bmap, start + 1, &next);
303 if (!ret) {
304 if (next <= end) {
305 ret = nilfs_mdt_read_block(inode, next, true, out_bh);
306 if (!ret)
307 *blkoff = next;
308 } else {
309 ret = -ENOENT;
310 }
311 }
312out:
313 return ret;
314}
315
316/**
317 * nilfs_mdt_delete_block - make a hole on the meta data file.
318 * @inode: inode of the meta data file
319 * @block: block offset
320 *
321 * Return Value: On success, zero is returned.
322 * On error, one of the following negative error code is returned.
323 *
324 * %-ENOMEM - Insufficient memory available.
325 *
326 * %-EIO - I/O error
327 */
328int nilfs_mdt_delete_block(struct inode *inode, unsigned long block)
329{
330 struct nilfs_inode_info *ii = NILFS_I(inode);
331 int err;
332
333 err = nilfs_bmap_delete(ii->i_bmap, block);
334 if (!err || err == -ENOENT) {
335 nilfs_mdt_mark_dirty(inode);
336 nilfs_mdt_forget_block(inode, block);
337 }
338 return err;
339}
340
341/**
342 * nilfs_mdt_forget_block - discard dirty state and try to remove the page
343 * @inode: inode of the meta data file
344 * @block: block offset
345 *
346 * nilfs_mdt_forget_block() clears a dirty flag of the specified buffer, and
347 * tries to release the page including the buffer from a page cache.
348 *
349 * Return Value: On success, 0 is returned. On error, one of the following
350 * negative error code is returned.
351 *
352 * %-EBUSY - page has an active buffer.
353 *
354 * %-ENOENT - page cache has no page addressed by the offset.
355 */
356int nilfs_mdt_forget_block(struct inode *inode, unsigned long block)
357{
358 pgoff_t index = (pgoff_t)block >>
359 (PAGE_SHIFT - inode->i_blkbits);
360 struct page *page;
361 unsigned long first_block;
362 int ret = 0;
363 int still_dirty;
364
365 page = find_lock_page(inode->i_mapping, index);
366 if (!page)
367 return -ENOENT;
368
369 wait_on_page_writeback(page);
370
371 first_block = (unsigned long)index <<
372 (PAGE_SHIFT - inode->i_blkbits);
373 if (page_has_buffers(page)) {
374 struct buffer_head *bh;
375
376 bh = nilfs_page_get_nth_block(page, block - first_block);
377 nilfs_forget_buffer(bh);
378 }
379 still_dirty = PageDirty(page);
380 unlock_page(page);
381 put_page(page);
382
383 if (still_dirty ||
384 invalidate_inode_pages2_range(inode->i_mapping, index, index) != 0)
385 ret = -EBUSY;
386 return ret;
387}
388
389int nilfs_mdt_fetch_dirty(struct inode *inode)
390{
391 struct nilfs_inode_info *ii = NILFS_I(inode);
392
393 if (nilfs_bmap_test_and_clear_dirty(ii->i_bmap)) {
394 set_bit(NILFS_I_DIRTY, &ii->i_state);
395 return 1;
396 }
397 return test_bit(NILFS_I_DIRTY, &ii->i_state);
398}
399
400static int
401nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
402{
403 struct inode *inode = page->mapping->host;
404 struct super_block *sb;
405 int err = 0;
406
407 if (inode && sb_rdonly(inode->i_sb)) {
408 /*
409 * It means that filesystem was remounted in read-only
410 * mode because of error or metadata corruption. But we
411 * have dirty pages that try to be flushed in background.
412 * So, here we simply discard this dirty page.
413 */
414 nilfs_clear_dirty_page(page, false);
415 unlock_page(page);
416 return -EROFS;
417 }
418
419 redirty_page_for_writepage(wbc, page);
420 unlock_page(page);
421
422 if (!inode)
423 return 0;
424
425 sb = inode->i_sb;
426
427 if (wbc->sync_mode == WB_SYNC_ALL)
428 err = nilfs_construct_segment(sb);
429 else if (wbc->for_reclaim)
430 nilfs_flush_segment(sb, inode->i_ino);
431
432 return err;
433}
434
435
436static const struct address_space_operations def_mdt_aops = {
437 .writepage = nilfs_mdt_write_page,
438};
439
440static const struct inode_operations def_mdt_iops;
441static const struct file_operations def_mdt_fops;
442
443
444int nilfs_mdt_init(struct inode *inode, gfp_t gfp_mask, size_t objsz)
445{
446 struct nilfs_mdt_info *mi;
447
448 mi = kzalloc(max(sizeof(*mi), objsz), GFP_NOFS);
449 if (!mi)
450 return -ENOMEM;
451
452 init_rwsem(&mi->mi_sem);
453 inode->i_private = mi;
454
455 inode->i_mode = S_IFREG;
456 mapping_set_gfp_mask(inode->i_mapping, gfp_mask);
457
458 inode->i_op = &def_mdt_iops;
459 inode->i_fop = &def_mdt_fops;
460 inode->i_mapping->a_ops = &def_mdt_aops;
461
462 return 0;
463}
464
465/**
466 * nilfs_mdt_clear - do cleanup for the metadata file
467 * @inode: inode of the metadata file
468 */
469void nilfs_mdt_clear(struct inode *inode)
470{
471 struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
472
473 if (mdi->mi_palloc_cache)
474 nilfs_palloc_destroy_cache(inode);
475}
476
477/**
478 * nilfs_mdt_destroy - release resources used by the metadata file
479 * @inode: inode of the metadata file
480 */
481void nilfs_mdt_destroy(struct inode *inode)
482{
483 struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
484
485 kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
486 kfree(mdi);
487}
488
489void nilfs_mdt_set_entry_size(struct inode *inode, unsigned int entry_size,
490 unsigned int header_size)
491{
492 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
493
494 mi->mi_entry_size = entry_size;
495 mi->mi_entries_per_block = i_blocksize(inode) / entry_size;
496 mi->mi_first_entry_offset = DIV_ROUND_UP(header_size, entry_size);
497}
498
499/**
500 * nilfs_mdt_setup_shadow_map - setup shadow map and bind it to metadata file
501 * @inode: inode of the metadata file
502 * @shadow: shadow mapping
503 */
504int nilfs_mdt_setup_shadow_map(struct inode *inode,
505 struct nilfs_shadow_map *shadow)
506{
507 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
508
509 INIT_LIST_HEAD(&shadow->frozen_buffers);
510 address_space_init_once(&shadow->frozen_data);
511 nilfs_mapping_init(&shadow->frozen_data, inode);
512 address_space_init_once(&shadow->frozen_btnodes);
513 nilfs_mapping_init(&shadow->frozen_btnodes, inode);
514 mi->mi_shadow = shadow;
515 return 0;
516}
517
518/**
519 * nilfs_mdt_save_to_shadow_map - copy bmap and dirty pages to shadow map
520 * @inode: inode of the metadata file
521 */
522int nilfs_mdt_save_to_shadow_map(struct inode *inode)
523{
524 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
525 struct nilfs_inode_info *ii = NILFS_I(inode);
526 struct nilfs_shadow_map *shadow = mi->mi_shadow;
527 int ret;
528
529 ret = nilfs_copy_dirty_pages(&shadow->frozen_data, inode->i_mapping);
530 if (ret)
531 goto out;
532
533 ret = nilfs_copy_dirty_pages(&shadow->frozen_btnodes,
534 &ii->i_btnode_cache);
535 if (ret)
536 goto out;
537
538 nilfs_bmap_save(ii->i_bmap, &shadow->bmap_store);
539 out:
540 return ret;
541}
542
543int nilfs_mdt_freeze_buffer(struct inode *inode, struct buffer_head *bh)
544{
545 struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
546 struct buffer_head *bh_frozen;
547 struct page *page;
548 int blkbits = inode->i_blkbits;
549
550 page = grab_cache_page(&shadow->frozen_data, bh->b_page->index);
551 if (!page)
552 return -ENOMEM;
553
554 if (!page_has_buffers(page))
555 create_empty_buffers(page, 1 << blkbits, 0);
556
557 bh_frozen = nilfs_page_get_nth_block(page, bh_offset(bh) >> blkbits);
558
559 if (!buffer_uptodate(bh_frozen))
560 nilfs_copy_buffer(bh_frozen, bh);
561 if (list_empty(&bh_frozen->b_assoc_buffers)) {
562 list_add_tail(&bh_frozen->b_assoc_buffers,
563 &shadow->frozen_buffers);
564 set_buffer_nilfs_redirected(bh);
565 } else {
566 brelse(bh_frozen); /* already frozen */
567 }
568
569 unlock_page(page);
570 put_page(page);
571 return 0;
572}
573
574struct buffer_head *
575nilfs_mdt_get_frozen_buffer(struct inode *inode, struct buffer_head *bh)
576{
577 struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
578 struct buffer_head *bh_frozen = NULL;
579 struct page *page;
580 int n;
581
582 page = find_lock_page(&shadow->frozen_data, bh->b_page->index);
583 if (page) {
584 if (page_has_buffers(page)) {
585 n = bh_offset(bh) >> inode->i_blkbits;
586 bh_frozen = nilfs_page_get_nth_block(page, n);
587 }
588 unlock_page(page);
589 put_page(page);
590 }
591 return bh_frozen;
592}
593
594static void nilfs_release_frozen_buffers(struct nilfs_shadow_map *shadow)
595{
596 struct list_head *head = &shadow->frozen_buffers;
597 struct buffer_head *bh;
598
599 while (!list_empty(head)) {
600 bh = list_first_entry(head, struct buffer_head,
601 b_assoc_buffers);
602 list_del_init(&bh->b_assoc_buffers);
603 brelse(bh); /* drop ref-count to make it releasable */
604 }
605}
606
607/**
608 * nilfs_mdt_restore_from_shadow_map - restore dirty pages and bmap state
609 * @inode: inode of the metadata file
610 */
611void nilfs_mdt_restore_from_shadow_map(struct inode *inode)
612{
613 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
614 struct nilfs_inode_info *ii = NILFS_I(inode);
615 struct nilfs_shadow_map *shadow = mi->mi_shadow;
616
617 down_write(&mi->mi_sem);
618
619 if (mi->mi_palloc_cache)
620 nilfs_palloc_clear_cache(inode);
621
622 nilfs_clear_dirty_pages(inode->i_mapping, true);
623 nilfs_copy_back_pages(inode->i_mapping, &shadow->frozen_data);
624
625 nilfs_clear_dirty_pages(&ii->i_btnode_cache, true);
626 nilfs_copy_back_pages(&ii->i_btnode_cache, &shadow->frozen_btnodes);
627
628 nilfs_bmap_restore(ii->i_bmap, &shadow->bmap_store);
629
630 up_write(&mi->mi_sem);
631}
632
633/**
634 * nilfs_mdt_clear_shadow_map - truncate pages in shadow map caches
635 * @inode: inode of the metadata file
636 */
637void nilfs_mdt_clear_shadow_map(struct inode *inode)
638{
639 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
640 struct nilfs_shadow_map *shadow = mi->mi_shadow;
641
642 down_write(&mi->mi_sem);
643 nilfs_release_frozen_buffers(shadow);
644 truncate_inode_pages(&shadow->frozen_data, 0);
645 truncate_inode_pages(&shadow->frozen_btnodes, 0);
646 up_write(&mi->mi_sem);
647}