2 * mdt.c - meta data file for NILFS
4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
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.
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.
16 * Written by Ryusuke Konishi.
19 #include <linux/buffer_head.h>
20 #include <linux/mpage.h>
22 #include <linux/writeback.h>
23 #include <linux/backing-dev.h>
24 #include <linux/swap.h>
25 #include <linux/slab.h>
31 #include "alloc.h" /* nilfs_palloc_destroy_cache() */
33 #include <trace/events/nilfs2.h>
35 #define NILFS_MDT_MAX_RA_BLOCKS (16 - 1)
39 nilfs_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 *))
44 struct nilfs_inode_info *ii = NILFS_I(inode);
48 /* Caller exclude read accesses using page lock */
50 /* set_buffer_new(bh); */
53 ret = nilfs_bmap_insert(ii->i_bmap, block, (unsigned long)bh);
57 set_buffer_mapped(bh);
59 kaddr = kmap_atomic(bh->b_page);
60 memset(kaddr + bh_offset(bh), 0, 1 << inode->i_blkbits);
62 init_block(inode, bh, kaddr);
63 flush_dcache_page(bh->b_page);
66 set_buffer_uptodate(bh);
67 mark_buffer_dirty(bh);
68 nilfs_mdt_mark_dirty(inode);
70 trace_nilfs2_mdt_insert_new_block(inode, inode->i_ino, block);
75 static int nilfs_mdt_create_block(struct inode *inode, unsigned long block,
76 struct buffer_head **out_bh,
77 void (*init_block)(struct inode *,
81 struct super_block *sb = inode->i_sb;
82 struct nilfs_transaction_info ti;
83 struct buffer_head *bh;
86 nilfs_transaction_begin(sb, &ti, 0);
89 bh = nilfs_grab_buffer(inode, inode->i_mapping, block, 0);
94 if (buffer_uptodate(bh))
98 if (buffer_uptodate(bh))
101 bh->b_bdev = sb->s_bdev;
102 err = nilfs_mdt_insert_new_block(inode, block, bh, init_block);
109 unlock_page(bh->b_page);
110 put_page(bh->b_page);
115 err = nilfs_transaction_commit(sb);
117 nilfs_transaction_abort(sb);
123 nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff,
124 int mode, struct buffer_head **out_bh)
126 struct buffer_head *bh;
130 bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
134 ret = -EEXIST; /* internal code */
135 if (buffer_uptodate(bh))
139 if (!trylock_buffer(bh)) {
143 } else /* mode == READ */
146 if (buffer_uptodate(bh)) {
151 ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum);
156 map_bh(bh, inode->i_sb, (sector_t)blknum);
158 bh->b_end_io = end_buffer_read_sync;
163 trace_nilfs2_mdt_submit_block(inode, inode->i_ino, blkoff, mode);
169 unlock_page(bh->b_page);
170 put_page(bh->b_page);
176 static int nilfs_mdt_read_block(struct inode *inode, unsigned long block,
177 int readahead, struct buffer_head **out_bh)
179 struct buffer_head *first_bh, *bh;
180 unsigned long blkoff;
181 int i, nr_ra_blocks = NILFS_MDT_MAX_RA_BLOCKS;
184 err = nilfs_mdt_submit_block(inode, block, READ, &first_bh);
185 if (err == -EEXIST) /* internal code */
193 for (i = 0; i < nr_ra_blocks; i++, blkoff++) {
194 err = nilfs_mdt_submit_block(inode, blkoff, READA, &bh);
195 if (likely(!err || err == -EEXIST))
197 else if (err != -EBUSY)
199 /* abort readahead if bmap lookup failed */
200 if (!buffer_locked(first_bh))
205 wait_on_buffer(first_bh);
209 if (!buffer_uptodate(first_bh))
222 * nilfs_mdt_get_block - read or create a buffer on meta data file.
223 * @inode: inode of the meta data file
224 * @blkoff: block offset
225 * @create: create flag
226 * @init_block: initializer used for newly allocated block
227 * @out_bh: output of a pointer to the buffer_head
229 * nilfs_mdt_get_block() looks up the specified buffer and tries to create
230 * a new buffer if @create is not zero. On success, the returned buffer is
231 * assured to be either existing or formatted using a buffer lock on success.
232 * @out_bh is substituted only when zero is returned.
234 * Return Value: On success, it returns 0. On error, the following negative
235 * error code is returned.
237 * %-ENOMEM - Insufficient memory available.
241 * %-ENOENT - the specified block does not exist (hole block)
243 * %-EROFS - Read only filesystem (for create mode)
245 int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create,
246 void (*init_block)(struct inode *,
247 struct buffer_head *, void *),
248 struct buffer_head **out_bh)
252 /* Should be rewritten with merging nilfs_mdt_read_block() */
254 ret = nilfs_mdt_read_block(inode, blkoff, !create, out_bh);
255 if (!create || ret != -ENOENT)
258 ret = nilfs_mdt_create_block(inode, blkoff, out_bh, init_block);
259 if (unlikely(ret == -EEXIST)) {
260 /* create = 0; */ /* limit read-create loop retries */
267 * nilfs_mdt_find_block - find and get a buffer on meta data file.
268 * @inode: inode of the meta data file
269 * @start: start block offset (inclusive)
270 * @end: end block offset (inclusive)
271 * @blkoff: block offset
272 * @out_bh: place to store a pointer to buffer_head struct
274 * nilfs_mdt_find_block() looks up an existing block in range of
275 * [@start, @end] and stores pointer to a buffer head of the block to
276 * @out_bh, and block offset to @blkoff, respectively. @out_bh and
277 * @blkoff are substituted only when zero is returned.
279 * Return Value: On success, it returns 0. On error, the following negative
280 * error code is returned.
282 * %-ENOMEM - Insufficient memory available.
286 * %-ENOENT - no block was found in the range
288 int nilfs_mdt_find_block(struct inode *inode, unsigned long start,
289 unsigned long end, unsigned long *blkoff,
290 struct buffer_head **out_bh)
295 if (unlikely(start > end))
298 ret = nilfs_mdt_read_block(inode, start, true, out_bh);
303 if (unlikely(ret != -ENOENT || start == ULONG_MAX))
306 ret = nilfs_bmap_seek_key(NILFS_I(inode)->i_bmap, start + 1, &next);
309 ret = nilfs_mdt_read_block(inode, next, true, out_bh);
321 * nilfs_mdt_delete_block - make a hole on the meta data file.
322 * @inode: inode of the meta data file
323 * @block: block offset
325 * Return Value: On success, zero is returned.
326 * On error, one of the following negative error code is returned.
328 * %-ENOMEM - Insufficient memory available.
332 int nilfs_mdt_delete_block(struct inode *inode, unsigned long block)
334 struct nilfs_inode_info *ii = NILFS_I(inode);
337 err = nilfs_bmap_delete(ii->i_bmap, block);
338 if (!err || err == -ENOENT) {
339 nilfs_mdt_mark_dirty(inode);
340 nilfs_mdt_forget_block(inode, block);
346 * nilfs_mdt_forget_block - discard dirty state and try to remove the page
347 * @inode: inode of the meta data file
348 * @block: block offset
350 * nilfs_mdt_forget_block() clears a dirty flag of the specified buffer, and
351 * tries to release the page including the buffer from a page cache.
353 * Return Value: On success, 0 is returned. On error, one of the following
354 * negative error code is returned.
356 * %-EBUSY - page has an active buffer.
358 * %-ENOENT - page cache has no page addressed by the offset.
360 int nilfs_mdt_forget_block(struct inode *inode, unsigned long block)
362 pgoff_t index = (pgoff_t)block >>
363 (PAGE_SHIFT - inode->i_blkbits);
365 unsigned long first_block;
369 page = find_lock_page(inode->i_mapping, index);
373 wait_on_page_writeback(page);
375 first_block = (unsigned long)index <<
376 (PAGE_SHIFT - inode->i_blkbits);
377 if (page_has_buffers(page)) {
378 struct buffer_head *bh;
380 bh = nilfs_page_get_nth_block(page, block - first_block);
381 nilfs_forget_buffer(bh);
383 still_dirty = PageDirty(page);
388 invalidate_inode_pages2_range(inode->i_mapping, index, index) != 0)
393 int nilfs_mdt_fetch_dirty(struct inode *inode)
395 struct nilfs_inode_info *ii = NILFS_I(inode);
397 if (nilfs_bmap_test_and_clear_dirty(ii->i_bmap)) {
398 set_bit(NILFS_I_DIRTY, &ii->i_state);
401 return test_bit(NILFS_I_DIRTY, &ii->i_state);
405 nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
407 struct inode *inode = page->mapping->host;
408 struct super_block *sb;
411 if (inode && (inode->i_sb->s_flags & MS_RDONLY)) {
413 * It means that filesystem was remounted in read-only
414 * mode because of error or metadata corruption. But we
415 * have dirty pages that try to be flushed in background.
416 * So, here we simply discard this dirty page.
418 nilfs_clear_dirty_page(page, false);
423 redirty_page_for_writepage(wbc, page);
431 if (wbc->sync_mode == WB_SYNC_ALL)
432 err = nilfs_construct_segment(sb);
433 else if (wbc->for_reclaim)
434 nilfs_flush_segment(sb, inode->i_ino);
440 static const struct address_space_operations def_mdt_aops = {
441 .writepage = nilfs_mdt_write_page,
444 static const struct inode_operations def_mdt_iops;
445 static const struct file_operations def_mdt_fops;
448 int nilfs_mdt_init(struct inode *inode, gfp_t gfp_mask, size_t objsz)
450 struct nilfs_mdt_info *mi;
452 mi = kzalloc(max(sizeof(*mi), objsz), GFP_NOFS);
456 init_rwsem(&mi->mi_sem);
457 inode->i_private = mi;
459 inode->i_mode = S_IFREG;
460 mapping_set_gfp_mask(inode->i_mapping, gfp_mask);
462 inode->i_op = &def_mdt_iops;
463 inode->i_fop = &def_mdt_fops;
464 inode->i_mapping->a_ops = &def_mdt_aops;
470 * nilfs_mdt_clear - do cleanup for the metadata file
471 * @inode: inode of the metadata file
473 void nilfs_mdt_clear(struct inode *inode)
475 struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
477 if (mdi->mi_palloc_cache)
478 nilfs_palloc_destroy_cache(inode);
482 * nilfs_mdt_destroy - release resources used by the metadata file
483 * @inode: inode of the metadata file
485 void nilfs_mdt_destroy(struct inode *inode)
487 struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
489 kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
493 void nilfs_mdt_set_entry_size(struct inode *inode, unsigned int entry_size,
494 unsigned int header_size)
496 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
498 mi->mi_entry_size = entry_size;
499 mi->mi_entries_per_block = (1 << inode->i_blkbits) / entry_size;
500 mi->mi_first_entry_offset = DIV_ROUND_UP(header_size, entry_size);
504 * nilfs_mdt_setup_shadow_map - setup shadow map and bind it to metadata file
505 * @inode: inode of the metadata file
506 * @shadow: shadow mapping
508 int nilfs_mdt_setup_shadow_map(struct inode *inode,
509 struct nilfs_shadow_map *shadow)
511 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
513 INIT_LIST_HEAD(&shadow->frozen_buffers);
514 address_space_init_once(&shadow->frozen_data);
515 nilfs_mapping_init(&shadow->frozen_data, inode);
516 address_space_init_once(&shadow->frozen_btnodes);
517 nilfs_mapping_init(&shadow->frozen_btnodes, inode);
518 mi->mi_shadow = shadow;
523 * nilfs_mdt_save_to_shadow_map - copy bmap and dirty pages to shadow map
524 * @inode: inode of the metadata file
526 int nilfs_mdt_save_to_shadow_map(struct inode *inode)
528 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
529 struct nilfs_inode_info *ii = NILFS_I(inode);
530 struct nilfs_shadow_map *shadow = mi->mi_shadow;
533 ret = nilfs_copy_dirty_pages(&shadow->frozen_data, inode->i_mapping);
537 ret = nilfs_copy_dirty_pages(&shadow->frozen_btnodes,
538 &ii->i_btnode_cache);
542 nilfs_bmap_save(ii->i_bmap, &shadow->bmap_store);
547 int nilfs_mdt_freeze_buffer(struct inode *inode, struct buffer_head *bh)
549 struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
550 struct buffer_head *bh_frozen;
552 int blkbits = inode->i_blkbits;
554 page = grab_cache_page(&shadow->frozen_data, bh->b_page->index);
558 if (!page_has_buffers(page))
559 create_empty_buffers(page, 1 << blkbits, 0);
561 bh_frozen = nilfs_page_get_nth_block(page, bh_offset(bh) >> blkbits);
563 if (!buffer_uptodate(bh_frozen))
564 nilfs_copy_buffer(bh_frozen, bh);
565 if (list_empty(&bh_frozen->b_assoc_buffers)) {
566 list_add_tail(&bh_frozen->b_assoc_buffers,
567 &shadow->frozen_buffers);
568 set_buffer_nilfs_redirected(bh);
570 brelse(bh_frozen); /* already frozen */
579 nilfs_mdt_get_frozen_buffer(struct inode *inode, struct buffer_head *bh)
581 struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
582 struct buffer_head *bh_frozen = NULL;
586 page = find_lock_page(&shadow->frozen_data, bh->b_page->index);
588 if (page_has_buffers(page)) {
589 n = bh_offset(bh) >> inode->i_blkbits;
590 bh_frozen = nilfs_page_get_nth_block(page, n);
598 static void nilfs_release_frozen_buffers(struct nilfs_shadow_map *shadow)
600 struct list_head *head = &shadow->frozen_buffers;
601 struct buffer_head *bh;
603 while (!list_empty(head)) {
604 bh = list_first_entry(head, struct buffer_head,
606 list_del_init(&bh->b_assoc_buffers);
607 brelse(bh); /* drop ref-count to make it releasable */
612 * nilfs_mdt_restore_from_shadow_map - restore dirty pages and bmap state
613 * @inode: inode of the metadata file
615 void nilfs_mdt_restore_from_shadow_map(struct inode *inode)
617 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
618 struct nilfs_inode_info *ii = NILFS_I(inode);
619 struct nilfs_shadow_map *shadow = mi->mi_shadow;
621 down_write(&mi->mi_sem);
623 if (mi->mi_palloc_cache)
624 nilfs_palloc_clear_cache(inode);
626 nilfs_clear_dirty_pages(inode->i_mapping, true);
627 nilfs_copy_back_pages(inode->i_mapping, &shadow->frozen_data);
629 nilfs_clear_dirty_pages(&ii->i_btnode_cache, true);
630 nilfs_copy_back_pages(&ii->i_btnode_cache, &shadow->frozen_btnodes);
632 nilfs_bmap_restore(ii->i_bmap, &shadow->bmap_store);
634 up_write(&mi->mi_sem);
638 * nilfs_mdt_clear_shadow_map - truncate pages in shadow map caches
639 * @inode: inode of the metadata file
641 void nilfs_mdt_clear_shadow_map(struct inode *inode)
643 struct nilfs_mdt_info *mi = NILFS_MDT(inode);
644 struct nilfs_shadow_map *shadow = mi->mi_shadow;
646 down_write(&mi->mi_sem);
647 nilfs_release_frozen_buffers(shadow);
648 truncate_inode_pages(&shadow->frozen_data, 0);
649 truncate_inode_pages(&shadow->frozen_btnodes, 0);
650 up_write(&mi->mi_sem);