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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 * Written by Ryusuke Konishi.
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>
25#include <linux/slab.h>
26#include "nilfs.h"
27#include "btnode.h"
28#include "segment.h"
29#include "page.h"
30#include "mdt.h"
31#include "alloc.h" /* nilfs_palloc_destroy_cache() */
32
33#include <trace/events/nilfs2.h>
34
35#define NILFS_MDT_MAX_RA_BLOCKS (16 - 1)
36
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
59 kaddr = kmap_atomic(bh->b_page);
60 memset(kaddr + bh_offset(bh), 0, i_blocksize(inode));
61 if (init_block)
62 init_block(inode, bh, kaddr);
63 flush_dcache_page(bh->b_page);
64 kunmap_atomic(kaddr);
65
66 set_buffer_uptodate(bh);
67 mark_buffer_dirty(bh);
68 nilfs_mdt_mark_dirty(inode);
69
70 trace_nilfs2_mdt_insert_new_block(inode, inode->i_ino, block);
71
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{
81 struct super_block *sb = inode->i_sb;
82 struct nilfs_transaction_info ti;
83 struct buffer_head *bh;
84 int err;
85
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;
94 if (buffer_uptodate(bh))
95 goto failed_bh;
96
97 wait_on_buffer(bh);
98 if (buffer_uptodate(bh))
99 goto failed_bh;
100
101 bh->b_bdev = sb->s_bdev;
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);
110 put_page(bh->b_page);
111 brelse(bh);
112
113 failed_unlock:
114 if (likely(!err))
115 err = nilfs_transaction_commit(sb);
116 else
117 nilfs_transaction_abort(sb);
118
119 return err;
120}
121
122static int
123nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff,
124 int mode, int mode_flags, struct buffer_head **out_bh)
125{
126 struct buffer_head *bh;
127 __u64 blknum = 0;
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_flags & REQ_RAHEAD) {
139 if (!trylock_buffer(bh)) {
140 ret = -EBUSY;
141 goto failed_bh;
142 }
143 } else /* mode == READ */
144 lock_buffer(bh);
145
146 if (buffer_uptodate(bh)) {
147 unlock_buffer(bh);
148 goto out;
149 }
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;
155 }
156 map_bh(bh, inode->i_sb, (sector_t)blknum);
157
158 bh->b_end_io = end_buffer_read_sync;
159 get_bh(bh);
160 submit_bh(mode, mode_flags, bh);
161 ret = 0;
162
163 trace_nilfs2_mdt_submit_block(inode, inode->i_ino, blkoff, mode);
164 out:
165 get_bh(bh);
166 *out_bh = bh;
167
168 failed_bh:
169 unlock_page(bh->b_page);
170 put_page(bh->b_page);
171 brelse(bh);
172 failed:
173 return ret;
174}
175
176static int nilfs_mdt_read_block(struct inode *inode, unsigned long block,
177 int readahead, struct buffer_head **out_bh)
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, REQ_OP_READ, 0, &first_bh);
185 if (err == -EEXIST) /* internal code */
186 goto out;
187
188 if (unlikely(err))
189 goto failed;
190
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, REQ_OP_READ,
195 REQ_RAHEAD, &bh);
196 if (likely(!err || err == -EEXIST))
197 brelse(bh);
198 else if (err != -EBUSY)
199 break;
200 /* abort readahead if bmap lookup failed */
201 if (!buffer_locked(first_bh))
202 goto out_no_wait;
203 }
204 }
205
206 wait_on_buffer(first_bh);
207
208 out_no_wait:
209 err = -EIO;
210 if (!buffer_uptodate(first_bh)) {
211 nilfs_msg(inode->i_sb, KERN_ERR,
212 "I/O error reading meta-data file (ino=%lu, block-offset=%lu)",
213 inode->i_ino, block);
214 goto failed_bh;
215 }
216 out:
217 *out_bh = first_bh;
218 return 0;
219
220 failed_bh:
221 brelse(first_bh);
222 failed:
223 return err;
224}
225
226/**
227 * nilfs_mdt_get_block - read or create a buffer on meta data file.
228 * @inode: inode of the meta data file
229 * @blkoff: block offset
230 * @create: create flag
231 * @init_block: initializer used for newly allocated block
232 * @out_bh: output of a pointer to the buffer_head
233 *
234 * nilfs_mdt_get_block() looks up the specified buffer and tries to create
235 * a new buffer if @create is not zero. On success, the returned buffer is
236 * assured to be either existing or formatted using a buffer lock on success.
237 * @out_bh is substituted only when zero is returned.
238 *
239 * Return Value: On success, it returns 0. On error, the following negative
240 * error code is returned.
241 *
242 * %-ENOMEM - Insufficient memory available.
243 *
244 * %-EIO - I/O error
245 *
246 * %-ENOENT - the specified block does not exist (hole block)
247 *
248 * %-EROFS - Read only filesystem (for create mode)
249 */
250int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create,
251 void (*init_block)(struct inode *,
252 struct buffer_head *, void *),
253 struct buffer_head **out_bh)
254{
255 int ret;
256
257 /* Should be rewritten with merging nilfs_mdt_read_block() */
258 retry:
259 ret = nilfs_mdt_read_block(inode, blkoff, !create, out_bh);
260 if (!create || ret != -ENOENT)
261 return ret;
262
263 ret = nilfs_mdt_create_block(inode, blkoff, out_bh, init_block);
264 if (unlikely(ret == -EEXIST)) {
265 /* create = 0; */ /* limit read-create loop retries */
266 goto retry;
267 }
268 return ret;
269}
270
271/**
272 * nilfs_mdt_find_block - find and get a buffer on meta data file.
273 * @inode: inode of the meta data file
274 * @start: start block offset (inclusive)
275 * @end: end block offset (inclusive)
276 * @blkoff: block offset
277 * @out_bh: place to store a pointer to buffer_head struct
278 *
279 * nilfs_mdt_find_block() looks up an existing block in range of
280 * [@start, @end] and stores pointer to a buffer head of the block to
281 * @out_bh, and block offset to @blkoff, respectively. @out_bh and
282 * @blkoff are substituted only when zero is returned.
283 *
284 * Return Value: On success, it returns 0. On error, the following negative
285 * error code is returned.
286 *
287 * %-ENOMEM - Insufficient memory available.
288 *
289 * %-EIO - I/O error
290 *
291 * %-ENOENT - no block was found in the range
292 */
293int nilfs_mdt_find_block(struct inode *inode, unsigned long start,
294 unsigned long end, unsigned long *blkoff,
295 struct buffer_head **out_bh)
296{
297 __u64 next;
298 int ret;
299
300 if (unlikely(start > end))
301 return -ENOENT;
302
303 ret = nilfs_mdt_read_block(inode, start, true, out_bh);
304 if (!ret) {
305 *blkoff = start;
306 goto out;
307 }
308 if (unlikely(ret != -ENOENT || start == ULONG_MAX))
309 goto out;
310
311 ret = nilfs_bmap_seek_key(NILFS_I(inode)->i_bmap, start + 1, &next);
312 if (!ret) {
313 if (next <= end) {
314 ret = nilfs_mdt_read_block(inode, next, true, out_bh);
315 if (!ret)
316 *blkoff = next;
317 } else {
318 ret = -ENOENT;
319 }
320 }
321out:
322 return ret;
323}
324
325/**
326 * nilfs_mdt_delete_block - make a hole on the meta data file.
327 * @inode: inode of the meta data file
328 * @block: block offset
329 *
330 * Return Value: On success, zero is returned.
331 * On error, one of the following negative error code is returned.
332 *
333 * %-ENOMEM - Insufficient memory available.
334 *
335 * %-EIO - I/O error
336 */
337int nilfs_mdt_delete_block(struct inode *inode, unsigned long block)
338{
339 struct nilfs_inode_info *ii = NILFS_I(inode);
340 int err;
341
342 err = nilfs_bmap_delete(ii->i_bmap, block);
343 if (!err || err == -ENOENT) {
344 nilfs_mdt_mark_dirty(inode);
345 nilfs_mdt_forget_block(inode, block);
346 }
347 return err;
348}
349
350/**
351 * nilfs_mdt_forget_block - discard dirty state and try to remove the page
352 * @inode: inode of the meta data file
353 * @block: block offset
354 *
355 * nilfs_mdt_forget_block() clears a dirty flag of the specified buffer, and
356 * tries to release the page including the buffer from a page cache.
357 *
358 * Return Value: On success, 0 is returned. On error, one of the following
359 * negative error code is returned.
360 *
361 * %-EBUSY - page has an active buffer.
362 *
363 * %-ENOENT - page cache has no page addressed by the offset.
364 */
365int nilfs_mdt_forget_block(struct inode *inode, unsigned long block)
366{
367 pgoff_t index = (pgoff_t)block >>
368 (PAGE_SHIFT - inode->i_blkbits);
369 struct page *page;
370 unsigned long first_block;
371 int ret = 0;
372 int still_dirty;
373
374 page = find_lock_page(inode->i_mapping, index);
375 if (!page)
376 return -ENOENT;
377
378 wait_on_page_writeback(page);
379
380 first_block = (unsigned long)index <<
381 (PAGE_SHIFT - inode->i_blkbits);
382 if (page_has_buffers(page)) {
383 struct buffer_head *bh;
384
385 bh = nilfs_page_get_nth_block(page, block - first_block);
386 nilfs_forget_buffer(bh);
387 }
388 still_dirty = PageDirty(page);
389 unlock_page(page);
390 put_page(page);
391
392 if (still_dirty ||
393 invalidate_inode_pages2_range(inode->i_mapping, index, index) != 0)
394 ret = -EBUSY;
395 return ret;
396}
397
398int nilfs_mdt_fetch_dirty(struct inode *inode)
399{
400 struct nilfs_inode_info *ii = NILFS_I(inode);
401
402 if (nilfs_bmap_test_and_clear_dirty(ii->i_bmap)) {
403 set_bit(NILFS_I_DIRTY, &ii->i_state);
404 return 1;
405 }
406 return test_bit(NILFS_I_DIRTY, &ii->i_state);
407}
408
409static int
410nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
411{
412 struct inode *inode = page->mapping->host;
413 struct super_block *sb;
414 int err = 0;
415
416 if (inode && sb_rdonly(inode->i_sb)) {
417 /*
418 * It means that filesystem was remounted in read-only
419 * mode because of error or metadata corruption. But we
420 * have dirty pages that try to be flushed in background.
421 * So, here we simply discard this dirty page.
422 */
423 nilfs_clear_dirty_page(page, false);
424 unlock_page(page);
425 return -EROFS;
426 }
427
428 redirty_page_for_writepage(wbc, page);
429 unlock_page(page);
430
431 if (!inode)
432 return 0;
433
434 sb = inode->i_sb;
435
436 if (wbc->sync_mode == WB_SYNC_ALL)
437 err = nilfs_construct_segment(sb);
438 else if (wbc->for_reclaim)
439 nilfs_flush_segment(sb, inode->i_ino);
440
441 return err;
442}
443
444
445static const struct address_space_operations def_mdt_aops = {
446 .writepage = nilfs_mdt_write_page,
447};
448
449static const struct inode_operations def_mdt_iops;
450static const struct file_operations def_mdt_fops;
451
452
453int nilfs_mdt_init(struct inode *inode, gfp_t gfp_mask, size_t objsz)
454{
455 struct nilfs_mdt_info *mi;
456
457 mi = kzalloc(max(sizeof(*mi), objsz), GFP_NOFS);
458 if (!mi)
459 return -ENOMEM;
460
461 init_rwsem(&mi->mi_sem);
462 inode->i_private = mi;
463
464 inode->i_mode = S_IFREG;
465 mapping_set_gfp_mask(inode->i_mapping, gfp_mask);
466
467 inode->i_op = &def_mdt_iops;
468 inode->i_fop = &def_mdt_fops;
469 inode->i_mapping->a_ops = &def_mdt_aops;
470
471 return 0;
472}
473
474/**
475 * nilfs_mdt_clear - do cleanup for the metadata file
476 * @inode: inode of the metadata file
477 */
478void nilfs_mdt_clear(struct inode *inode)
479{
480 struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
481
482 if (mdi->mi_palloc_cache)
483 nilfs_palloc_destroy_cache(inode);
484}
485
486/**
487 * nilfs_mdt_destroy - release resources used by the metadata file
488 * @inode: inode of the metadata file
489 */
490void nilfs_mdt_destroy(struct inode *inode)
491{
492 struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
493
494 kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
495 kfree(mdi);
496}
497
498void nilfs_mdt_set_entry_size(struct inode *inode, unsigned int entry_size,
499 unsigned int header_size)
500{
501 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
502
503 mi->mi_entry_size = entry_size;
504 mi->mi_entries_per_block = i_blocksize(inode) / entry_size;
505 mi->mi_first_entry_offset = DIV_ROUND_UP(header_size, entry_size);
506}
507
508/**
509 * nilfs_mdt_setup_shadow_map - setup shadow map and bind it to metadata file
510 * @inode: inode of the metadata file
511 * @shadow: shadow mapping
512 */
513int nilfs_mdt_setup_shadow_map(struct inode *inode,
514 struct nilfs_shadow_map *shadow)
515{
516 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
517
518 INIT_LIST_HEAD(&shadow->frozen_buffers);
519 address_space_init_once(&shadow->frozen_data);
520 nilfs_mapping_init(&shadow->frozen_data, inode);
521 address_space_init_once(&shadow->frozen_btnodes);
522 nilfs_mapping_init(&shadow->frozen_btnodes, inode);
523 mi->mi_shadow = shadow;
524 return 0;
525}
526
527/**
528 * nilfs_mdt_save_to_shadow_map - copy bmap and dirty pages to shadow map
529 * @inode: inode of the metadata file
530 */
531int nilfs_mdt_save_to_shadow_map(struct inode *inode)
532{
533 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
534 struct nilfs_inode_info *ii = NILFS_I(inode);
535 struct nilfs_shadow_map *shadow = mi->mi_shadow;
536 int ret;
537
538 ret = nilfs_copy_dirty_pages(&shadow->frozen_data, inode->i_mapping);
539 if (ret)
540 goto out;
541
542 ret = nilfs_copy_dirty_pages(&shadow->frozen_btnodes,
543 &ii->i_btnode_cache);
544 if (ret)
545 goto out;
546
547 nilfs_bmap_save(ii->i_bmap, &shadow->bmap_store);
548 out:
549 return ret;
550}
551
552int nilfs_mdt_freeze_buffer(struct inode *inode, struct buffer_head *bh)
553{
554 struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
555 struct buffer_head *bh_frozen;
556 struct page *page;
557 int blkbits = inode->i_blkbits;
558
559 page = grab_cache_page(&shadow->frozen_data, bh->b_page->index);
560 if (!page)
561 return -ENOMEM;
562
563 if (!page_has_buffers(page))
564 create_empty_buffers(page, 1 << blkbits, 0);
565
566 bh_frozen = nilfs_page_get_nth_block(page, bh_offset(bh) >> blkbits);
567
568 if (!buffer_uptodate(bh_frozen))
569 nilfs_copy_buffer(bh_frozen, bh);
570 if (list_empty(&bh_frozen->b_assoc_buffers)) {
571 list_add_tail(&bh_frozen->b_assoc_buffers,
572 &shadow->frozen_buffers);
573 set_buffer_nilfs_redirected(bh);
574 } else {
575 brelse(bh_frozen); /* already frozen */
576 }
577
578 unlock_page(page);
579 put_page(page);
580 return 0;
581}
582
583struct buffer_head *
584nilfs_mdt_get_frozen_buffer(struct inode *inode, struct buffer_head *bh)
585{
586 struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
587 struct buffer_head *bh_frozen = NULL;
588 struct page *page;
589 int n;
590
591 page = find_lock_page(&shadow->frozen_data, bh->b_page->index);
592 if (page) {
593 if (page_has_buffers(page)) {
594 n = bh_offset(bh) >> inode->i_blkbits;
595 bh_frozen = nilfs_page_get_nth_block(page, n);
596 }
597 unlock_page(page);
598 put_page(page);
599 }
600 return bh_frozen;
601}
602
603static void nilfs_release_frozen_buffers(struct nilfs_shadow_map *shadow)
604{
605 struct list_head *head = &shadow->frozen_buffers;
606 struct buffer_head *bh;
607
608 while (!list_empty(head)) {
609 bh = list_first_entry(head, struct buffer_head,
610 b_assoc_buffers);
611 list_del_init(&bh->b_assoc_buffers);
612 brelse(bh); /* drop ref-count to make it releasable */
613 }
614}
615
616/**
617 * nilfs_mdt_restore_from_shadow_map - restore dirty pages and bmap state
618 * @inode: inode of the metadata file
619 */
620void nilfs_mdt_restore_from_shadow_map(struct inode *inode)
621{
622 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
623 struct nilfs_inode_info *ii = NILFS_I(inode);
624 struct nilfs_shadow_map *shadow = mi->mi_shadow;
625
626 down_write(&mi->mi_sem);
627
628 if (mi->mi_palloc_cache)
629 nilfs_palloc_clear_cache(inode);
630
631 nilfs_clear_dirty_pages(inode->i_mapping, true);
632 nilfs_copy_back_pages(inode->i_mapping, &shadow->frozen_data);
633
634 nilfs_clear_dirty_pages(&ii->i_btnode_cache, true);
635 nilfs_copy_back_pages(&ii->i_btnode_cache, &shadow->frozen_btnodes);
636
637 nilfs_bmap_restore(ii->i_bmap, &shadow->bmap_store);
638
639 up_write(&mi->mi_sem);
640}
641
642/**
643 * nilfs_mdt_clear_shadow_map - truncate pages in shadow map caches
644 * @inode: inode of the metadata file
645 */
646void nilfs_mdt_clear_shadow_map(struct inode *inode)
647{
648 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
649 struct nilfs_shadow_map *shadow = mi->mi_shadow;
650
651 down_write(&mi->mi_sem);
652 nilfs_release_frozen_buffers(shadow);
653 truncate_inode_pages(&shadow->frozen_data, 0);
654 truncate_inode_pages(&shadow->frozen_btnodes, 0);
655 up_write(&mi->mi_sem);
656}
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_msg(inode->i_sb, KERN_ERR,
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}