Loading...
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * 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 struct folio *folio = bh->b_folio;
37 void *from;
38 int ret;
39
40 /* Caller exclude read accesses using page lock */
41
42 /* set_buffer_new(bh); */
43 bh->b_blocknr = 0;
44
45 ret = nilfs_bmap_insert(ii->i_bmap, block, (unsigned long)bh);
46 if (unlikely(ret))
47 return ret;
48
49 set_buffer_mapped(bh);
50
51 /* Initialize block (block size > PAGE_SIZE not yet supported) */
52 from = kmap_local_folio(folio, offset_in_folio(folio, bh->b_data));
53 memset(from, 0, bh->b_size);
54 if (init_block)
55 init_block(inode, bh, from);
56 kunmap_local(from);
57
58 flush_dcache_folio(folio);
59
60 set_buffer_uptodate(bh);
61 mark_buffer_dirty(bh);
62 nilfs_mdt_mark_dirty(inode);
63
64 trace_nilfs2_mdt_insert_new_block(inode, inode->i_ino, block);
65
66 return 0;
67}
68
69static int nilfs_mdt_create_block(struct inode *inode, unsigned long block,
70 struct buffer_head **out_bh,
71 void (*init_block)(struct inode *,
72 struct buffer_head *,
73 void *))
74{
75 struct super_block *sb = inode->i_sb;
76 struct nilfs_transaction_info ti;
77 struct buffer_head *bh;
78 int err;
79
80 nilfs_transaction_begin(sb, &ti, 0);
81
82 err = -ENOMEM;
83 bh = nilfs_grab_buffer(inode, inode->i_mapping, block, 0);
84 if (unlikely(!bh))
85 goto failed_unlock;
86
87 err = -EEXIST;
88 if (buffer_uptodate(bh))
89 goto failed_bh;
90
91 wait_on_buffer(bh);
92 if (buffer_uptodate(bh))
93 goto failed_bh;
94
95 err = nilfs_mdt_insert_new_block(inode, block, bh, init_block);
96 if (likely(!err)) {
97 get_bh(bh);
98 *out_bh = bh;
99 }
100
101 failed_bh:
102 folio_unlock(bh->b_folio);
103 folio_put(bh->b_folio);
104 brelse(bh);
105
106 failed_unlock:
107 if (likely(!err))
108 err = nilfs_transaction_commit(sb);
109 else
110 nilfs_transaction_abort(sb);
111
112 return err;
113}
114
115static int
116nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff, blk_opf_t opf,
117 struct buffer_head **out_bh)
118{
119 struct buffer_head *bh;
120 __u64 blknum = 0;
121 int ret = -ENOMEM;
122
123 bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
124 if (unlikely(!bh))
125 goto failed;
126
127 ret = -EEXIST; /* internal code */
128 if (buffer_uptodate(bh))
129 goto out;
130
131 if (opf & REQ_RAHEAD) {
132 if (!trylock_buffer(bh)) {
133 ret = -EBUSY;
134 goto failed_bh;
135 }
136 } else /* opf == REQ_OP_READ */
137 lock_buffer(bh);
138
139 if (buffer_uptodate(bh)) {
140 unlock_buffer(bh);
141 goto out;
142 }
143
144 ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum);
145 if (unlikely(ret)) {
146 unlock_buffer(bh);
147 goto failed_bh;
148 }
149 map_bh(bh, inode->i_sb, (sector_t)blknum);
150
151 bh->b_end_io = end_buffer_read_sync;
152 get_bh(bh);
153 submit_bh(opf, bh);
154 ret = 0;
155
156 trace_nilfs2_mdt_submit_block(inode, inode->i_ino, blkoff,
157 opf & REQ_OP_MASK);
158 out:
159 get_bh(bh);
160 *out_bh = bh;
161
162 failed_bh:
163 folio_unlock(bh->b_folio);
164 folio_put(bh->b_folio);
165 brelse(bh);
166 failed:
167 return ret;
168}
169
170static int nilfs_mdt_read_block(struct inode *inode, unsigned long block,
171 int readahead, struct buffer_head **out_bh)
172{
173 struct buffer_head *first_bh, *bh;
174 unsigned long blkoff;
175 int i, nr_ra_blocks = NILFS_MDT_MAX_RA_BLOCKS;
176 int err;
177
178 err = nilfs_mdt_submit_block(inode, block, REQ_OP_READ, &first_bh);
179 if (err == -EEXIST) /* internal code */
180 goto out;
181
182 if (unlikely(err))
183 goto failed;
184
185 if (readahead) {
186 blkoff = block + 1;
187 for (i = 0; i < nr_ra_blocks; i++, blkoff++) {
188 err = nilfs_mdt_submit_block(inode, blkoff,
189 REQ_OP_READ | REQ_RAHEAD, &bh);
190 if (likely(!err || err == -EEXIST))
191 brelse(bh);
192 else if (err != -EBUSY)
193 break;
194 /* abort readahead if bmap lookup failed */
195 if (!buffer_locked(first_bh))
196 goto out_no_wait;
197 }
198 }
199
200 wait_on_buffer(first_bh);
201
202 out_no_wait:
203 err = -EIO;
204 if (!buffer_uptodate(first_bh)) {
205 nilfs_err(inode->i_sb,
206 "I/O error reading meta-data file (ino=%lu, block-offset=%lu)",
207 inode->i_ino, block);
208 goto failed_bh;
209 }
210 out:
211 *out_bh = first_bh;
212 return 0;
213
214 failed_bh:
215 brelse(first_bh);
216 failed:
217 return err;
218}
219
220/**
221 * nilfs_mdt_get_block - read or create a buffer on meta data file.
222 * @inode: inode of the meta data file
223 * @blkoff: block offset
224 * @create: create flag
225 * @init_block: initializer used for newly allocated block
226 * @out_bh: output of a pointer to the buffer_head
227 *
228 * nilfs_mdt_get_block() looks up the specified buffer and tries to create
229 * a new buffer if @create is not zero. On success, the returned buffer is
230 * assured to be either existing or formatted using a buffer lock on success.
231 * @out_bh is substituted only when zero is returned.
232 *
233 * Return Value: On success, it returns 0. On error, the following negative
234 * error code is returned.
235 *
236 * %-ENOMEM - Insufficient memory available.
237 *
238 * %-EIO - I/O error
239 *
240 * %-ENOENT - the specified block does not exist (hole block)
241 *
242 * %-EROFS - Read only filesystem (for create mode)
243 */
244int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create,
245 void (*init_block)(struct inode *,
246 struct buffer_head *, void *),
247 struct buffer_head **out_bh)
248{
249 int ret;
250
251 /* Should be rewritten with merging nilfs_mdt_read_block() */
252 retry:
253 ret = nilfs_mdt_read_block(inode, blkoff, !create, out_bh);
254 if (!create || ret != -ENOENT)
255 return ret;
256
257 ret = nilfs_mdt_create_block(inode, blkoff, out_bh, init_block);
258 if (unlikely(ret == -EEXIST)) {
259 /* create = 0; */ /* limit read-create loop retries */
260 goto retry;
261 }
262 return ret;
263}
264
265/**
266 * nilfs_mdt_find_block - find and get a buffer on meta data file.
267 * @inode: inode of the meta data file
268 * @start: start block offset (inclusive)
269 * @end: end block offset (inclusive)
270 * @blkoff: block offset
271 * @out_bh: place to store a pointer to buffer_head struct
272 *
273 * nilfs_mdt_find_block() looks up an existing block in range of
274 * [@start, @end] and stores pointer to a buffer head of the block to
275 * @out_bh, and block offset to @blkoff, respectively. @out_bh and
276 * @blkoff are substituted only when zero is returned.
277 *
278 * Return Value: On success, it returns 0. On error, the following negative
279 * error code is returned.
280 *
281 * %-ENOMEM - Insufficient memory available.
282 *
283 * %-EIO - I/O error
284 *
285 * %-ENOENT - no block was found in the range
286 */
287int nilfs_mdt_find_block(struct inode *inode, unsigned long start,
288 unsigned long end, unsigned long *blkoff,
289 struct buffer_head **out_bh)
290{
291 __u64 next;
292 int ret;
293
294 if (unlikely(start > end))
295 return -ENOENT;
296
297 ret = nilfs_mdt_read_block(inode, start, true, out_bh);
298 if (!ret) {
299 *blkoff = start;
300 goto out;
301 }
302 if (unlikely(ret != -ENOENT || start == ULONG_MAX))
303 goto out;
304
305 ret = nilfs_bmap_seek_key(NILFS_I(inode)->i_bmap, start + 1, &next);
306 if (!ret) {
307 if (next <= end) {
308 ret = nilfs_mdt_read_block(inode, next, true, out_bh);
309 if (!ret)
310 *blkoff = next;
311 } else {
312 ret = -ENOENT;
313 }
314 }
315out:
316 return ret;
317}
318
319/**
320 * nilfs_mdt_delete_block - make a hole on the meta data file.
321 * @inode: inode of the meta data file
322 * @block: block offset
323 *
324 * Return Value: On success, zero is returned.
325 * On error, one of the following negative error code is returned.
326 *
327 * %-ENOMEM - Insufficient memory available.
328 *
329 * %-EIO - I/O error
330 */
331int nilfs_mdt_delete_block(struct inode *inode, unsigned long block)
332{
333 struct nilfs_inode_info *ii = NILFS_I(inode);
334 int err;
335
336 err = nilfs_bmap_delete(ii->i_bmap, block);
337 if (!err || err == -ENOENT) {
338 nilfs_mdt_mark_dirty(inode);
339 nilfs_mdt_forget_block(inode, block);
340 }
341 return err;
342}
343
344/**
345 * nilfs_mdt_forget_block - discard dirty state and try to remove the page
346 * @inode: inode of the meta data file
347 * @block: block offset
348 *
349 * nilfs_mdt_forget_block() clears a dirty flag of the specified buffer, and
350 * tries to release the page including the buffer from a page cache.
351 *
352 * Return Value: On success, 0 is returned. On error, one of the following
353 * negative error code is returned.
354 *
355 * %-EBUSY - page has an active buffer.
356 *
357 * %-ENOENT - page cache has no page addressed by the offset.
358 */
359int nilfs_mdt_forget_block(struct inode *inode, unsigned long block)
360{
361 pgoff_t index = block >> (PAGE_SHIFT - inode->i_blkbits);
362 struct folio *folio;
363 struct buffer_head *bh;
364 int ret = 0;
365 int still_dirty;
366
367 folio = filemap_lock_folio(inode->i_mapping, index);
368 if (IS_ERR(folio))
369 return -ENOENT;
370
371 folio_wait_writeback(folio);
372
373 bh = folio_buffers(folio);
374 if (bh) {
375 unsigned long first_block = index <<
376 (PAGE_SHIFT - inode->i_blkbits);
377 bh = get_nth_bh(bh, block - first_block);
378 nilfs_forget_buffer(bh);
379 }
380 still_dirty = folio_test_dirty(folio);
381 folio_unlock(folio);
382 folio_put(folio);
383
384 if (still_dirty ||
385 invalidate_inode_pages2_range(inode->i_mapping, index, index) != 0)
386 ret = -EBUSY;
387 return ret;
388}
389
390int nilfs_mdt_fetch_dirty(struct inode *inode)
391{
392 struct nilfs_inode_info *ii = NILFS_I(inode);
393
394 if (nilfs_bmap_test_and_clear_dirty(ii->i_bmap)) {
395 set_bit(NILFS_I_DIRTY, &ii->i_state);
396 return 1;
397 }
398 return test_bit(NILFS_I_DIRTY, &ii->i_state);
399}
400
401static int nilfs_mdt_write_folio(struct folio *folio,
402 struct writeback_control *wbc)
403{
404 struct inode *inode = folio->mapping->host;
405 struct super_block *sb;
406 int err = 0;
407
408 if (inode && sb_rdonly(inode->i_sb)) {
409 /*
410 * It means that filesystem was remounted in read-only
411 * mode because of error or metadata corruption. But we
412 * have dirty folios that try to be flushed in background.
413 * So, here we simply discard this dirty folio.
414 */
415 nilfs_clear_folio_dirty(folio);
416 folio_unlock(folio);
417 return -EROFS;
418 }
419
420 folio_redirty_for_writepage(wbc, folio);
421 folio_unlock(folio);
422
423 if (!inode)
424 return 0;
425
426 sb = inode->i_sb;
427
428 if (wbc->sync_mode == WB_SYNC_ALL)
429 err = nilfs_construct_segment(sb);
430 else if (wbc->for_reclaim)
431 nilfs_flush_segment(sb, inode->i_ino);
432
433 return err;
434}
435
436static int nilfs_mdt_writeback(struct address_space *mapping,
437 struct writeback_control *wbc)
438{
439 struct folio *folio = NULL;
440 int error;
441
442 while ((folio = writeback_iter(mapping, wbc, folio, &error)))
443 error = nilfs_mdt_write_folio(folio, wbc);
444
445 return error;
446}
447
448static const struct address_space_operations def_mdt_aops = {
449 .dirty_folio = block_dirty_folio,
450 .invalidate_folio = block_invalidate_folio,
451 .writepages = nilfs_mdt_writeback,
452 .migrate_folio = buffer_migrate_folio_norefs,
453};
454
455static const struct inode_operations def_mdt_iops;
456static const struct file_operations def_mdt_fops;
457
458
459int nilfs_mdt_init(struct inode *inode, gfp_t gfp_mask, size_t objsz)
460{
461 struct nilfs_mdt_info *mi;
462
463 mi = kzalloc(max(sizeof(*mi), objsz), GFP_NOFS);
464 if (!mi)
465 return -ENOMEM;
466
467 init_rwsem(&mi->mi_sem);
468 inode->i_private = mi;
469
470 inode->i_mode = S_IFREG;
471 mapping_set_gfp_mask(inode->i_mapping, gfp_mask);
472
473 inode->i_op = &def_mdt_iops;
474 inode->i_fop = &def_mdt_fops;
475 inode->i_mapping->a_ops = &def_mdt_aops;
476
477 return 0;
478}
479
480/**
481 * nilfs_mdt_clear - do cleanup for the metadata file
482 * @inode: inode of the metadata file
483 */
484void nilfs_mdt_clear(struct inode *inode)
485{
486 struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
487 struct nilfs_shadow_map *shadow = mdi->mi_shadow;
488
489 if (mdi->mi_palloc_cache)
490 nilfs_palloc_destroy_cache(inode);
491
492 if (shadow) {
493 struct inode *s_inode = shadow->inode;
494
495 shadow->inode = NULL;
496 iput(s_inode);
497 mdi->mi_shadow = NULL;
498 }
499}
500
501/**
502 * nilfs_mdt_destroy - release resources used by the metadata file
503 * @inode: inode of the metadata file
504 */
505void nilfs_mdt_destroy(struct inode *inode)
506{
507 struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
508
509 kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
510 kfree(mdi);
511}
512
513void nilfs_mdt_set_entry_size(struct inode *inode, unsigned int entry_size,
514 unsigned int header_size)
515{
516 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
517
518 mi->mi_entry_size = entry_size;
519 mi->mi_entries_per_block = i_blocksize(inode) / entry_size;
520 mi->mi_first_entry_offset = DIV_ROUND_UP(header_size, entry_size);
521}
522
523/**
524 * nilfs_mdt_setup_shadow_map - setup shadow map and bind it to metadata file
525 * @inode: inode of the metadata file
526 * @shadow: shadow mapping
527 */
528int nilfs_mdt_setup_shadow_map(struct inode *inode,
529 struct nilfs_shadow_map *shadow)
530{
531 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
532 struct inode *s_inode;
533
534 INIT_LIST_HEAD(&shadow->frozen_buffers);
535
536 s_inode = nilfs_iget_for_shadow(inode);
537 if (IS_ERR(s_inode))
538 return PTR_ERR(s_inode);
539
540 shadow->inode = s_inode;
541 mi->mi_shadow = shadow;
542 return 0;
543}
544
545/**
546 * nilfs_mdt_save_to_shadow_map - copy bmap and dirty pages to shadow map
547 * @inode: inode of the metadata file
548 */
549int nilfs_mdt_save_to_shadow_map(struct inode *inode)
550{
551 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
552 struct nilfs_inode_info *ii = NILFS_I(inode);
553 struct nilfs_shadow_map *shadow = mi->mi_shadow;
554 struct inode *s_inode = shadow->inode;
555 int ret;
556
557 ret = nilfs_copy_dirty_pages(s_inode->i_mapping, inode->i_mapping);
558 if (ret)
559 goto out;
560
561 ret = nilfs_copy_dirty_pages(NILFS_I(s_inode)->i_assoc_inode->i_mapping,
562 ii->i_assoc_inode->i_mapping);
563 if (ret)
564 goto out;
565
566 nilfs_bmap_save(ii->i_bmap, &shadow->bmap_store);
567 out:
568 return ret;
569}
570
571int nilfs_mdt_freeze_buffer(struct inode *inode, struct buffer_head *bh)
572{
573 struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
574 struct buffer_head *bh_frozen;
575 struct folio *folio;
576 int blkbits = inode->i_blkbits;
577
578 folio = filemap_grab_folio(shadow->inode->i_mapping,
579 bh->b_folio->index);
580 if (IS_ERR(folio))
581 return PTR_ERR(folio);
582
583 bh_frozen = folio_buffers(folio);
584 if (!bh_frozen)
585 bh_frozen = create_empty_buffers(folio, 1 << blkbits, 0);
586
587 bh_frozen = get_nth_bh(bh_frozen,
588 offset_in_folio(folio, bh->b_data) >> blkbits);
589
590 if (!buffer_uptodate(bh_frozen))
591 nilfs_copy_buffer(bh_frozen, bh);
592 if (list_empty(&bh_frozen->b_assoc_buffers)) {
593 list_add_tail(&bh_frozen->b_assoc_buffers,
594 &shadow->frozen_buffers);
595 set_buffer_nilfs_redirected(bh);
596 } else {
597 brelse(bh_frozen); /* already frozen */
598 }
599
600 folio_unlock(folio);
601 folio_put(folio);
602 return 0;
603}
604
605struct buffer_head *
606nilfs_mdt_get_frozen_buffer(struct inode *inode, struct buffer_head *bh)
607{
608 struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
609 struct buffer_head *bh_frozen = NULL;
610 struct folio *folio;
611 int n;
612
613 folio = filemap_lock_folio(shadow->inode->i_mapping,
614 bh->b_folio->index);
615 if (!IS_ERR(folio)) {
616 bh_frozen = folio_buffers(folio);
617 if (bh_frozen) {
618 n = offset_in_folio(folio, bh->b_data) >>
619 inode->i_blkbits;
620 bh_frozen = get_nth_bh(bh_frozen, n);
621 }
622 folio_unlock(folio);
623 folio_put(folio);
624 }
625 return bh_frozen;
626}
627
628static void nilfs_release_frozen_buffers(struct nilfs_shadow_map *shadow)
629{
630 struct list_head *head = &shadow->frozen_buffers;
631 struct buffer_head *bh;
632
633 while (!list_empty(head)) {
634 bh = list_first_entry(head, struct buffer_head,
635 b_assoc_buffers);
636 list_del_init(&bh->b_assoc_buffers);
637 brelse(bh); /* drop ref-count to make it releasable */
638 }
639}
640
641/**
642 * nilfs_mdt_restore_from_shadow_map - restore dirty pages and bmap state
643 * @inode: inode of the metadata file
644 */
645void nilfs_mdt_restore_from_shadow_map(struct inode *inode)
646{
647 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
648 struct nilfs_inode_info *ii = NILFS_I(inode);
649 struct nilfs_shadow_map *shadow = mi->mi_shadow;
650
651 down_write(&mi->mi_sem);
652
653 if (mi->mi_palloc_cache)
654 nilfs_palloc_clear_cache(inode);
655
656 nilfs_clear_dirty_pages(inode->i_mapping);
657 nilfs_copy_back_pages(inode->i_mapping, shadow->inode->i_mapping);
658
659 nilfs_clear_dirty_pages(ii->i_assoc_inode->i_mapping);
660 nilfs_copy_back_pages(ii->i_assoc_inode->i_mapping,
661 NILFS_I(shadow->inode)->i_assoc_inode->i_mapping);
662
663 nilfs_bmap_restore(ii->i_bmap, &shadow->bmap_store);
664
665 up_write(&mi->mi_sem);
666}
667
668/**
669 * nilfs_mdt_clear_shadow_map - truncate pages in shadow map caches
670 * @inode: inode of the metadata file
671 */
672void nilfs_mdt_clear_shadow_map(struct inode *inode)
673{
674 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
675 struct nilfs_shadow_map *shadow = mi->mi_shadow;
676 struct inode *shadow_btnc_inode = NILFS_I(shadow->inode)->i_assoc_inode;
677
678 down_write(&mi->mi_sem);
679 nilfs_release_frozen_buffers(shadow);
680 truncate_inode_pages(shadow->inode->i_mapping, 0);
681 truncate_inode_pages(shadow_btnc_inode->i_mapping, 0);
682 up_write(&mi->mi_sem);
683}
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 = page->mapping->host;
379 struct super_block *sb;
380 int err = 0;
381
382 if (inode && (inode->i_sb->s_flags & MS_RDONLY)) {
383 /*
384 * It means that filesystem was remounted in read-only
385 * mode because of error or metadata corruption. But we
386 * have dirty pages that try to be flushed in background.
387 * So, here we simply discard this dirty page.
388 */
389 nilfs_clear_dirty_page(page, false);
390 unlock_page(page);
391 return -EROFS;
392 }
393
394 redirty_page_for_writepage(wbc, page);
395 unlock_page(page);
396
397 if (!inode)
398 return 0;
399
400 sb = inode->i_sb;
401
402 if (wbc->sync_mode == WB_SYNC_ALL)
403 err = nilfs_construct_segment(sb);
404 else if (wbc->for_reclaim)
405 nilfs_flush_segment(sb, inode->i_ino);
406
407 return err;
408}
409
410
411static const struct address_space_operations def_mdt_aops = {
412 .writepage = nilfs_mdt_write_page,
413};
414
415static const struct inode_operations def_mdt_iops;
416static const struct file_operations def_mdt_fops;
417
418
419int nilfs_mdt_init(struct inode *inode, gfp_t gfp_mask, size_t objsz)
420{
421 struct nilfs_mdt_info *mi;
422
423 mi = kzalloc(max(sizeof(*mi), objsz), GFP_NOFS);
424 if (!mi)
425 return -ENOMEM;
426
427 init_rwsem(&mi->mi_sem);
428 inode->i_private = mi;
429
430 inode->i_mode = S_IFREG;
431 mapping_set_gfp_mask(inode->i_mapping, gfp_mask);
432 inode->i_mapping->backing_dev_info = inode->i_sb->s_bdi;
433
434 inode->i_op = &def_mdt_iops;
435 inode->i_fop = &def_mdt_fops;
436 inode->i_mapping->a_ops = &def_mdt_aops;
437
438 return 0;
439}
440
441void nilfs_mdt_set_entry_size(struct inode *inode, unsigned entry_size,
442 unsigned header_size)
443{
444 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
445
446 mi->mi_entry_size = entry_size;
447 mi->mi_entries_per_block = (1 << inode->i_blkbits) / entry_size;
448 mi->mi_first_entry_offset = DIV_ROUND_UP(header_size, entry_size);
449}
450
451/**
452 * nilfs_mdt_setup_shadow_map - setup shadow map and bind it to metadata file
453 * @inode: inode of the metadata file
454 * @shadow: shadow mapping
455 */
456int nilfs_mdt_setup_shadow_map(struct inode *inode,
457 struct nilfs_shadow_map *shadow)
458{
459 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
460 struct backing_dev_info *bdi = inode->i_sb->s_bdi;
461
462 INIT_LIST_HEAD(&shadow->frozen_buffers);
463 address_space_init_once(&shadow->frozen_data);
464 nilfs_mapping_init(&shadow->frozen_data, inode, bdi);
465 address_space_init_once(&shadow->frozen_btnodes);
466 nilfs_mapping_init(&shadow->frozen_btnodes, inode, bdi);
467 mi->mi_shadow = shadow;
468 return 0;
469}
470
471/**
472 * nilfs_mdt_save_to_shadow_map - copy bmap and dirty pages to shadow map
473 * @inode: inode of the metadata file
474 */
475int nilfs_mdt_save_to_shadow_map(struct inode *inode)
476{
477 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
478 struct nilfs_inode_info *ii = NILFS_I(inode);
479 struct nilfs_shadow_map *shadow = mi->mi_shadow;
480 int ret;
481
482 ret = nilfs_copy_dirty_pages(&shadow->frozen_data, inode->i_mapping);
483 if (ret)
484 goto out;
485
486 ret = nilfs_copy_dirty_pages(&shadow->frozen_btnodes,
487 &ii->i_btnode_cache);
488 if (ret)
489 goto out;
490
491 nilfs_bmap_save(ii->i_bmap, &shadow->bmap_store);
492 out:
493 return ret;
494}
495
496int nilfs_mdt_freeze_buffer(struct inode *inode, struct buffer_head *bh)
497{
498 struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
499 struct buffer_head *bh_frozen;
500 struct page *page;
501 int blkbits = inode->i_blkbits;
502
503 page = grab_cache_page(&shadow->frozen_data, bh->b_page->index);
504 if (!page)
505 return -ENOMEM;
506
507 if (!page_has_buffers(page))
508 create_empty_buffers(page, 1 << blkbits, 0);
509
510 bh_frozen = nilfs_page_get_nth_block(page, bh_offset(bh) >> blkbits);
511
512 if (!buffer_uptodate(bh_frozen))
513 nilfs_copy_buffer(bh_frozen, bh);
514 if (list_empty(&bh_frozen->b_assoc_buffers)) {
515 list_add_tail(&bh_frozen->b_assoc_buffers,
516 &shadow->frozen_buffers);
517 set_buffer_nilfs_redirected(bh);
518 } else {
519 brelse(bh_frozen); /* already frozen */
520 }
521
522 unlock_page(page);
523 page_cache_release(page);
524 return 0;
525}
526
527struct buffer_head *
528nilfs_mdt_get_frozen_buffer(struct inode *inode, struct buffer_head *bh)
529{
530 struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
531 struct buffer_head *bh_frozen = NULL;
532 struct page *page;
533 int n;
534
535 page = find_lock_page(&shadow->frozen_data, bh->b_page->index);
536 if (page) {
537 if (page_has_buffers(page)) {
538 n = bh_offset(bh) >> inode->i_blkbits;
539 bh_frozen = nilfs_page_get_nth_block(page, n);
540 }
541 unlock_page(page);
542 page_cache_release(page);
543 }
544 return bh_frozen;
545}
546
547static void nilfs_release_frozen_buffers(struct nilfs_shadow_map *shadow)
548{
549 struct list_head *head = &shadow->frozen_buffers;
550 struct buffer_head *bh;
551
552 while (!list_empty(head)) {
553 bh = list_first_entry(head, struct buffer_head,
554 b_assoc_buffers);
555 list_del_init(&bh->b_assoc_buffers);
556 brelse(bh); /* drop ref-count to make it releasable */
557 }
558}
559
560/**
561 * nilfs_mdt_restore_from_shadow_map - restore dirty pages and bmap state
562 * @inode: inode of the metadata file
563 */
564void nilfs_mdt_restore_from_shadow_map(struct inode *inode)
565{
566 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
567 struct nilfs_inode_info *ii = NILFS_I(inode);
568 struct nilfs_shadow_map *shadow = mi->mi_shadow;
569
570 down_write(&mi->mi_sem);
571
572 if (mi->mi_palloc_cache)
573 nilfs_palloc_clear_cache(inode);
574
575 nilfs_clear_dirty_pages(inode->i_mapping, true);
576 nilfs_copy_back_pages(inode->i_mapping, &shadow->frozen_data);
577
578 nilfs_clear_dirty_pages(&ii->i_btnode_cache, true);
579 nilfs_copy_back_pages(&ii->i_btnode_cache, &shadow->frozen_btnodes);
580
581 nilfs_bmap_restore(ii->i_bmap, &shadow->bmap_store);
582
583 up_write(&mi->mi_sem);
584}
585
586/**
587 * nilfs_mdt_clear_shadow_map - truncate pages in shadow map caches
588 * @inode: inode of the metadata file
589 */
590void nilfs_mdt_clear_shadow_map(struct inode *inode)
591{
592 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
593 struct nilfs_shadow_map *shadow = mi->mi_shadow;
594
595 down_write(&mi->mi_sem);
596 nilfs_release_frozen_buffers(shadow);
597 truncate_inode_pages(&shadow->frozen_data, 0);
598 truncate_inode_pages(&shadow->frozen_btnodes, 0);
599 up_write(&mi->mi_sem);
600}