xref: /linux/fs/jfs/jfs_metapage.c (revision cb787f4ac0c2e439ea8d7e6387b925f74576bdf8)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *   Copyright (C) International Business Machines Corp., 2000-2005
4  *   Portions Copyright (C) Christoph Hellwig, 2001-2002
5  */
6 
7 #include <linux/blkdev.h>
8 #include <linux/fs.h>
9 #include <linux/mm.h>
10 #include <linux/module.h>
11 #include <linux/bio.h>
12 #include <linux/slab.h>
13 #include <linux/init.h>
14 #include <linux/buffer_head.h>
15 #include <linux/mempool.h>
16 #include <linux/seq_file.h>
17 #include <linux/writeback.h>
18 #include "jfs_incore.h"
19 #include "jfs_superblock.h"
20 #include "jfs_filsys.h"
21 #include "jfs_metapage.h"
22 #include "jfs_txnmgr.h"
23 #include "jfs_debug.h"
24 
25 #ifdef CONFIG_JFS_STATISTICS
26 static struct {
27 	uint	pagealloc;	/* # of page allocations */
28 	uint	pagefree;	/* # of page frees */
29 	uint	lockwait;	/* # of sleeping lock_metapage() calls */
30 } mpStat;
31 #endif
32 
33 #define metapage_locked(mp) test_bit(META_locked, &(mp)->flag)
34 #define trylock_metapage(mp) test_and_set_bit_lock(META_locked, &(mp)->flag)
35 
36 static inline void unlock_metapage(struct metapage *mp)
37 {
38 	clear_bit_unlock(META_locked, &mp->flag);
39 	wake_up(&mp->wait);
40 }
41 
42 static inline void __lock_metapage(struct metapage *mp)
43 {
44 	DECLARE_WAITQUEUE(wait, current);
45 	INCREMENT(mpStat.lockwait);
46 	add_wait_queue_exclusive(&mp->wait, &wait);
47 	do {
48 		set_current_state(TASK_UNINTERRUPTIBLE);
49 		if (metapage_locked(mp)) {
50 			folio_unlock(mp->folio);
51 			io_schedule();
52 			folio_lock(mp->folio);
53 		}
54 	} while (trylock_metapage(mp));
55 	__set_current_state(TASK_RUNNING);
56 	remove_wait_queue(&mp->wait, &wait);
57 }
58 
59 /*
60  * Must have mp->folio locked
61  */
62 static inline void lock_metapage(struct metapage *mp)
63 {
64 	if (trylock_metapage(mp))
65 		__lock_metapage(mp);
66 }
67 
68 #define METAPOOL_MIN_PAGES 32
69 static struct kmem_cache *metapage_cache;
70 static mempool_t *metapage_mempool;
71 
72 #define MPS_PER_PAGE (PAGE_SIZE >> L2PSIZE)
73 
74 #if MPS_PER_PAGE > 1
75 
76 struct meta_anchor {
77 	int mp_count;
78 	atomic_t io_count;
79 	blk_status_t status;
80 	struct metapage *mp[MPS_PER_PAGE];
81 };
82 
83 static inline struct metapage *folio_to_mp(struct folio *folio, int offset)
84 {
85 	struct meta_anchor *anchor = folio->private;
86 
87 	if (!anchor)
88 		return NULL;
89 	return anchor->mp[offset >> L2PSIZE];
90 }
91 
92 static inline int insert_metapage(struct folio *folio, struct metapage *mp)
93 {
94 	struct meta_anchor *a;
95 	int index;
96 	int l2mp_blocks;	/* log2 blocks per metapage */
97 
98 	a = folio->private;
99 	if (!a) {
100 		a = kzalloc(sizeof(struct meta_anchor), GFP_NOFS);
101 		if (!a)
102 			return -ENOMEM;
103 		folio_attach_private(folio, a);
104 		kmap(&folio->page);
105 	}
106 
107 	if (mp) {
108 		l2mp_blocks = L2PSIZE - folio->mapping->host->i_blkbits;
109 		index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
110 		a->mp_count++;
111 		a->mp[index] = mp;
112 	}
113 
114 	return 0;
115 }
116 
117 static inline void remove_metapage(struct folio *folio, struct metapage *mp)
118 {
119 	struct meta_anchor *a = folio->private;
120 	int l2mp_blocks = L2PSIZE - folio->mapping->host->i_blkbits;
121 	int index;
122 
123 	index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
124 
125 	BUG_ON(a->mp[index] != mp);
126 
127 	a->mp[index] = NULL;
128 	if (--a->mp_count == 0) {
129 		kfree(a);
130 		folio_detach_private(folio);
131 		kunmap(&folio->page);
132 	}
133 }
134 
135 static inline void inc_io(struct folio *folio)
136 {
137 	struct meta_anchor *anchor = folio->private;
138 
139 	atomic_inc(&anchor->io_count);
140 }
141 
142 static inline void dec_io(struct folio *folio, blk_status_t status,
143 		void (*handler)(struct folio *, blk_status_t))
144 {
145 	struct meta_anchor *anchor = folio->private;
146 
147 	if (anchor->status == BLK_STS_OK)
148 		anchor->status = status;
149 
150 	if (atomic_dec_and_test(&anchor->io_count))
151 		handler(folio, anchor->status);
152 }
153 
154 #else
155 static inline struct metapage *folio_to_mp(struct folio *folio, int offset)
156 {
157 	return folio->private;
158 }
159 
160 static inline int insert_metapage(struct folio *folio, struct metapage *mp)
161 {
162 	if (mp) {
163 		folio_attach_private(folio, mp);
164 		kmap(&folio->page);
165 	}
166 	return 0;
167 }
168 
169 static inline void remove_metapage(struct folio *folio, struct metapage *mp)
170 {
171 	folio_detach_private(folio);
172 	kunmap(&folio->page);
173 }
174 
175 #define inc_io(folio) do {} while(0)
176 #define dec_io(folio, status, handler) handler(folio, status)
177 
178 #endif
179 
180 static inline struct metapage *alloc_metapage(gfp_t gfp_mask)
181 {
182 	struct metapage *mp = mempool_alloc(metapage_mempool, gfp_mask);
183 
184 	if (mp) {
185 		mp->lid = 0;
186 		mp->lsn = 0;
187 		mp->data = NULL;
188 		mp->clsn = 0;
189 		mp->log = NULL;
190 		init_waitqueue_head(&mp->wait);
191 	}
192 	return mp;
193 }
194 
195 static inline void free_metapage(struct metapage *mp)
196 {
197 	mempool_free(mp, metapage_mempool);
198 }
199 
200 int __init metapage_init(void)
201 {
202 	/*
203 	 * Allocate the metapage structures
204 	 */
205 	metapage_cache = kmem_cache_create("jfs_mp", sizeof(struct metapage),
206 					   0, 0, NULL);
207 	if (metapage_cache == NULL)
208 		return -ENOMEM;
209 
210 	metapage_mempool = mempool_create_slab_pool(METAPOOL_MIN_PAGES,
211 						    metapage_cache);
212 
213 	if (metapage_mempool == NULL) {
214 		kmem_cache_destroy(metapage_cache);
215 		return -ENOMEM;
216 	}
217 
218 	return 0;
219 }
220 
221 void metapage_exit(void)
222 {
223 	mempool_destroy(metapage_mempool);
224 	kmem_cache_destroy(metapage_cache);
225 }
226 
227 static inline void drop_metapage(struct folio *folio, struct metapage *mp)
228 {
229 	if (mp->count || mp->nohomeok || test_bit(META_dirty, &mp->flag) ||
230 	    test_bit(META_io, &mp->flag))
231 		return;
232 	remove_metapage(folio, mp);
233 	INCREMENT(mpStat.pagefree);
234 	free_metapage(mp);
235 }
236 
237 /*
238  * Metapage address space operations
239  */
240 
241 static sector_t metapage_get_blocks(struct inode *inode, sector_t lblock,
242 				    int *len)
243 {
244 	int rc = 0;
245 	int xflag;
246 	s64 xaddr;
247 	sector_t file_blocks = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
248 			       inode->i_blkbits;
249 
250 	if (lblock >= file_blocks)
251 		return 0;
252 	if (lblock + *len > file_blocks)
253 		*len = file_blocks - lblock;
254 
255 	if (inode->i_ino) {
256 		rc = xtLookup(inode, (s64)lblock, *len, &xflag, &xaddr, len, 0);
257 		if ((rc == 0) && *len)
258 			lblock = (sector_t)xaddr;
259 		else
260 			lblock = 0;
261 	} /* else no mapping */
262 
263 	return lblock;
264 }
265 
266 static void last_read_complete(struct folio *folio, blk_status_t status)
267 {
268 	if (status)
269 		printk(KERN_ERR "Read error %d at %#llx\n", status,
270 				folio_pos(folio));
271 
272 	folio_end_read(folio, status == 0);
273 }
274 
275 static void metapage_read_end_io(struct bio *bio)
276 {
277 	struct folio *folio = bio->bi_private;
278 
279 	dec_io(folio, bio->bi_status, last_read_complete);
280 	bio_put(bio);
281 }
282 
283 static void remove_from_logsync(struct metapage *mp)
284 {
285 	struct jfs_log *log = mp->log;
286 	unsigned long flags;
287 /*
288  * This can race.  Recheck that log hasn't been set to null, and after
289  * acquiring logsync lock, recheck lsn
290  */
291 	if (!log)
292 		return;
293 
294 	LOGSYNC_LOCK(log, flags);
295 	if (mp->lsn) {
296 		mp->log = NULL;
297 		mp->lsn = 0;
298 		mp->clsn = 0;
299 		log->count--;
300 		list_del(&mp->synclist);
301 	}
302 	LOGSYNC_UNLOCK(log, flags);
303 }
304 
305 static void last_write_complete(struct folio *folio, blk_status_t status)
306 {
307 	struct metapage *mp;
308 	unsigned int offset;
309 
310 	if (status) {
311 		int err = blk_status_to_errno(status);
312 		printk(KERN_ERR "metapage_write_end_io: I/O error\n");
313 		mapping_set_error(folio->mapping, err);
314 	}
315 
316 	for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
317 		mp = folio_to_mp(folio, offset);
318 		if (mp && test_bit(META_io, &mp->flag)) {
319 			if (mp->lsn)
320 				remove_from_logsync(mp);
321 			clear_bit(META_io, &mp->flag);
322 		}
323 		/*
324 		 * I'd like to call drop_metapage here, but I don't think it's
325 		 * safe unless I have the page locked
326 		 */
327 	}
328 	folio_end_writeback(folio);
329 }
330 
331 static void metapage_write_end_io(struct bio *bio)
332 {
333 	struct folio *folio = bio->bi_private;
334 
335 	BUG_ON(!folio->private);
336 
337 	dec_io(folio, bio->bi_status, last_write_complete);
338 	bio_put(bio);
339 }
340 
341 static int metapage_write_folio(struct folio *folio,
342 		struct writeback_control *wbc, void *unused)
343 {
344 	struct bio *bio = NULL;
345 	int block_offset;	/* block offset of mp within page */
346 	struct inode *inode = folio->mapping->host;
347 	int blocks_per_mp = JFS_SBI(inode->i_sb)->nbperpage;
348 	int len;
349 	int xlen;
350 	struct metapage *mp;
351 	int redirty = 0;
352 	sector_t lblock;
353 	int nr_underway = 0;
354 	sector_t pblock;
355 	sector_t next_block = 0;
356 	sector_t page_start;
357 	unsigned long bio_bytes = 0;
358 	unsigned long bio_offset = 0;
359 	int offset;
360 	int bad_blocks = 0;
361 
362 	page_start = folio_pos(folio) >> inode->i_blkbits;
363 	BUG_ON(!folio_test_locked(folio));
364 	BUG_ON(folio_test_writeback(folio));
365 	folio_start_writeback(folio);
366 
367 	for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
368 		mp = folio_to_mp(folio, offset);
369 
370 		if (!mp || !test_bit(META_dirty, &mp->flag))
371 			continue;
372 
373 		if (mp->nohomeok && !test_bit(META_forcewrite, &mp->flag)) {
374 			redirty = 1;
375 			/*
376 			 * Make sure this page isn't blocked indefinitely.
377 			 * If the journal isn't undergoing I/O, push it
378 			 */
379 			if (mp->log && !(mp->log->cflag & logGC_PAGEOUT))
380 				jfs_flush_journal(mp->log, 0);
381 			continue;
382 		}
383 
384 		clear_bit(META_dirty, &mp->flag);
385 		set_bit(META_io, &mp->flag);
386 		block_offset = offset >> inode->i_blkbits;
387 		lblock = page_start + block_offset;
388 		if (bio) {
389 			if (xlen && lblock == next_block) {
390 				/* Contiguous, in memory & on disk */
391 				len = min(xlen, blocks_per_mp);
392 				xlen -= len;
393 				bio_bytes += len << inode->i_blkbits;
394 				continue;
395 			}
396 			/* Not contiguous */
397 			bio_add_folio_nofail(bio, folio, bio_bytes, bio_offset);
398 			/*
399 			 * Increment counter before submitting i/o to keep
400 			 * count from hitting zero before we're through
401 			 */
402 			inc_io(folio);
403 			if (!bio->bi_iter.bi_size)
404 				goto dump_bio;
405 			submit_bio(bio);
406 			nr_underway++;
407 			bio = NULL;
408 		} else
409 			inc_io(folio);
410 		xlen = (folio_size(folio) - offset) >> inode->i_blkbits;
411 		pblock = metapage_get_blocks(inode, lblock, &xlen);
412 		if (!pblock) {
413 			printk(KERN_ERR "JFS: metapage_get_blocks failed\n");
414 			/*
415 			 * We already called inc_io(), but can't cancel it
416 			 * with dec_io() until we're done with the page
417 			 */
418 			bad_blocks++;
419 			continue;
420 		}
421 		len = min(xlen, (int)JFS_SBI(inode->i_sb)->nbperpage);
422 
423 		bio = bio_alloc(inode->i_sb->s_bdev, 1, REQ_OP_WRITE, GFP_NOFS);
424 		bio->bi_iter.bi_sector = pblock << (inode->i_blkbits - 9);
425 		bio->bi_end_io = metapage_write_end_io;
426 		bio->bi_private = folio;
427 
428 		/* Don't call bio_add_page yet, we may add to this vec */
429 		bio_offset = offset;
430 		bio_bytes = len << inode->i_blkbits;
431 
432 		xlen -= len;
433 		next_block = lblock + len;
434 	}
435 	if (bio) {
436 		bio_add_folio_nofail(bio, folio, bio_bytes, bio_offset);
437 		if (!bio->bi_iter.bi_size)
438 			goto dump_bio;
439 
440 		submit_bio(bio);
441 		nr_underway++;
442 	}
443 	if (redirty)
444 		folio_redirty_for_writepage(wbc, folio);
445 
446 	folio_unlock(folio);
447 
448 	if (bad_blocks)
449 		goto err_out;
450 
451 	if (nr_underway == 0)
452 		folio_end_writeback(folio);
453 
454 	return 0;
455 dump_bio:
456 	print_hex_dump(KERN_ERR, "JFS: dump of bio: ", DUMP_PREFIX_ADDRESS, 16,
457 		       4, bio, sizeof(*bio), 0);
458 	bio_put(bio);
459 	folio_unlock(folio);
460 	dec_io(folio, BLK_STS_OK, last_write_complete);
461 err_out:
462 	while (bad_blocks--)
463 		dec_io(folio, BLK_STS_OK, last_write_complete);
464 	return -EIO;
465 }
466 
467 static int metapage_writepages(struct address_space *mapping,
468 		struct writeback_control *wbc)
469 {
470 	struct blk_plug plug;
471 	int err;
472 
473 	blk_start_plug(&plug);
474 	err = write_cache_pages(mapping, wbc, metapage_write_folio, NULL);
475 	blk_finish_plug(&plug);
476 
477 	return err;
478 }
479 
480 static int metapage_read_folio(struct file *fp, struct folio *folio)
481 {
482 	struct inode *inode = folio->mapping->host;
483 	struct bio *bio = NULL;
484 	int block_offset;
485 	int blocks_per_page = i_blocks_per_folio(inode, folio);
486 	sector_t page_start;	/* address of page in fs blocks */
487 	sector_t pblock;
488 	int xlen;
489 	unsigned int len;
490 	int offset;
491 
492 	BUG_ON(!folio_test_locked(folio));
493 	page_start = folio_pos(folio) >> inode->i_blkbits;
494 
495 	block_offset = 0;
496 	while (block_offset < blocks_per_page) {
497 		xlen = blocks_per_page - block_offset;
498 		pblock = metapage_get_blocks(inode, page_start + block_offset,
499 					     &xlen);
500 		if (pblock) {
501 			if (!folio->private)
502 				insert_metapage(folio, NULL);
503 			inc_io(folio);
504 			if (bio)
505 				submit_bio(bio);
506 
507 			bio = bio_alloc(inode->i_sb->s_bdev, 1, REQ_OP_READ,
508 					GFP_NOFS);
509 			bio->bi_iter.bi_sector =
510 				pblock << (inode->i_blkbits - 9);
511 			bio->bi_end_io = metapage_read_end_io;
512 			bio->bi_private = folio;
513 			len = xlen << inode->i_blkbits;
514 			offset = block_offset << inode->i_blkbits;
515 			bio_add_folio_nofail(bio, folio, len, offset);
516 			block_offset += xlen;
517 		} else
518 			block_offset++;
519 	}
520 	if (bio)
521 		submit_bio(bio);
522 	else
523 		folio_unlock(folio);
524 
525 	return 0;
526 }
527 
528 static bool metapage_release_folio(struct folio *folio, gfp_t gfp_mask)
529 {
530 	struct metapage *mp;
531 	bool ret = true;
532 	int offset;
533 
534 	for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
535 		mp = folio_to_mp(folio, offset);
536 
537 		if (!mp)
538 			continue;
539 
540 		jfs_info("metapage_release_folio: mp = 0x%p", mp);
541 		if (mp->count || mp->nohomeok ||
542 		    test_bit(META_dirty, &mp->flag)) {
543 			jfs_info("count = %ld, nohomeok = %d", mp->count,
544 				 mp->nohomeok);
545 			ret = false;
546 			continue;
547 		}
548 		if (mp->lsn)
549 			remove_from_logsync(mp);
550 		remove_metapage(folio, mp);
551 		INCREMENT(mpStat.pagefree);
552 		free_metapage(mp);
553 	}
554 	return ret;
555 }
556 
557 static void metapage_invalidate_folio(struct folio *folio, size_t offset,
558 				    size_t length)
559 {
560 	BUG_ON(offset || length < folio_size(folio));
561 
562 	BUG_ON(folio_test_writeback(folio));
563 
564 	metapage_release_folio(folio, 0);
565 }
566 
567 const struct address_space_operations jfs_metapage_aops = {
568 	.read_folio	= metapage_read_folio,
569 	.writepages	= metapage_writepages,
570 	.release_folio	= metapage_release_folio,
571 	.invalidate_folio = metapage_invalidate_folio,
572 	.dirty_folio	= filemap_dirty_folio,
573 };
574 
575 struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
576 				unsigned int size, int absolute,
577 				unsigned long new)
578 {
579 	int l2BlocksPerPage;
580 	int l2bsize;
581 	struct address_space *mapping;
582 	struct metapage *mp = NULL;
583 	struct folio *folio;
584 	unsigned long page_index;
585 	unsigned long page_offset;
586 
587 	jfs_info("__get_metapage: ino = %ld, lblock = 0x%lx, abs=%d",
588 		 inode->i_ino, lblock, absolute);
589 
590 	l2bsize = inode->i_blkbits;
591 	l2BlocksPerPage = PAGE_SHIFT - l2bsize;
592 	page_index = lblock >> l2BlocksPerPage;
593 	page_offset = (lblock - (page_index << l2BlocksPerPage)) << l2bsize;
594 	if ((page_offset + size) > PAGE_SIZE) {
595 		jfs_err("MetaData crosses page boundary!!");
596 		jfs_err("lblock = %lx, size  = %d", lblock, size);
597 		dump_stack();
598 		return NULL;
599 	}
600 	if (absolute)
601 		mapping = JFS_SBI(inode->i_sb)->direct_inode->i_mapping;
602 	else {
603 		/*
604 		 * If an nfs client tries to read an inode that is larger
605 		 * than any existing inodes, we may try to read past the
606 		 * end of the inode map
607 		 */
608 		if ((lblock << inode->i_blkbits) >= inode->i_size)
609 			return NULL;
610 		mapping = inode->i_mapping;
611 	}
612 
613 	if (new && (PSIZE == PAGE_SIZE)) {
614 		folio = filemap_grab_folio(mapping, page_index);
615 		if (IS_ERR(folio)) {
616 			jfs_err("filemap_grab_folio failed!");
617 			return NULL;
618 		}
619 		folio_mark_uptodate(folio);
620 	} else {
621 		folio = read_mapping_folio(mapping, page_index, NULL);
622 		if (IS_ERR(folio)) {
623 			jfs_err("read_mapping_page failed!");
624 			return NULL;
625 		}
626 		folio_lock(folio);
627 	}
628 
629 	mp = folio_to_mp(folio, page_offset);
630 	if (mp) {
631 		if (mp->logical_size != size) {
632 			jfs_error(inode->i_sb,
633 				  "get_mp->logical_size != size\n");
634 			jfs_err("logical_size = %d, size = %d",
635 				mp->logical_size, size);
636 			dump_stack();
637 			goto unlock;
638 		}
639 		mp->count++;
640 		lock_metapage(mp);
641 		if (test_bit(META_discard, &mp->flag)) {
642 			if (!new) {
643 				jfs_error(inode->i_sb,
644 					  "using a discarded metapage\n");
645 				discard_metapage(mp);
646 				goto unlock;
647 			}
648 			clear_bit(META_discard, &mp->flag);
649 		}
650 	} else {
651 		INCREMENT(mpStat.pagealloc);
652 		mp = alloc_metapage(GFP_NOFS);
653 		if (!mp)
654 			goto unlock;
655 		mp->folio = folio;
656 		mp->sb = inode->i_sb;
657 		mp->flag = 0;
658 		mp->xflag = COMMIT_PAGE;
659 		mp->count = 1;
660 		mp->nohomeok = 0;
661 		mp->logical_size = size;
662 		mp->data = folio_address(folio) + page_offset;
663 		mp->index = lblock;
664 		if (unlikely(insert_metapage(folio, mp))) {
665 			free_metapage(mp);
666 			goto unlock;
667 		}
668 		lock_metapage(mp);
669 	}
670 
671 	if (new) {
672 		jfs_info("zeroing mp = 0x%p", mp);
673 		memset(mp->data, 0, PSIZE);
674 	}
675 
676 	folio_unlock(folio);
677 	jfs_info("__get_metapage: returning = 0x%p data = 0x%p", mp, mp->data);
678 	return mp;
679 
680 unlock:
681 	folio_unlock(folio);
682 	return NULL;
683 }
684 
685 void grab_metapage(struct metapage * mp)
686 {
687 	jfs_info("grab_metapage: mp = 0x%p", mp);
688 	folio_get(mp->folio);
689 	folio_lock(mp->folio);
690 	mp->count++;
691 	lock_metapage(mp);
692 	folio_unlock(mp->folio);
693 }
694 
695 static int metapage_write_one(struct folio *folio)
696 {
697 	struct address_space *mapping = folio->mapping;
698 	struct writeback_control wbc = {
699 		.sync_mode = WB_SYNC_ALL,
700 		.nr_to_write = folio_nr_pages(folio),
701 	};
702 	int ret = 0;
703 
704 	BUG_ON(!folio_test_locked(folio));
705 
706 	folio_wait_writeback(folio);
707 
708 	if (folio_clear_dirty_for_io(folio)) {
709 		folio_get(folio);
710 		ret = metapage_write_folio(folio, &wbc, NULL);
711 		if (ret == 0)
712 			folio_wait_writeback(folio);
713 		folio_put(folio);
714 	} else {
715 		folio_unlock(folio);
716 	}
717 
718 	if (!ret)
719 		ret = filemap_check_errors(mapping);
720 	return ret;
721 }
722 
723 void force_metapage(struct metapage *mp)
724 {
725 	struct folio *folio = mp->folio;
726 	jfs_info("force_metapage: mp = 0x%p", mp);
727 	set_bit(META_forcewrite, &mp->flag);
728 	clear_bit(META_sync, &mp->flag);
729 	folio_get(folio);
730 	folio_lock(folio);
731 	folio_mark_dirty(folio);
732 	if (metapage_write_one(folio))
733 		jfs_error(mp->sb, "metapage_write_one() failed\n");
734 	clear_bit(META_forcewrite, &mp->flag);
735 	folio_put(folio);
736 }
737 
738 void hold_metapage(struct metapage *mp)
739 {
740 	folio_lock(mp->folio);
741 }
742 
743 void put_metapage(struct metapage *mp)
744 {
745 	if (mp->count || mp->nohomeok) {
746 		/* Someone else will release this */
747 		folio_unlock(mp->folio);
748 		return;
749 	}
750 	folio_get(mp->folio);
751 	mp->count++;
752 	lock_metapage(mp);
753 	folio_unlock(mp->folio);
754 	release_metapage(mp);
755 }
756 
757 void release_metapage(struct metapage * mp)
758 {
759 	struct folio *folio = mp->folio;
760 	jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag);
761 
762 	folio_lock(folio);
763 	unlock_metapage(mp);
764 
765 	assert(mp->count);
766 	if (--mp->count || mp->nohomeok) {
767 		folio_unlock(folio);
768 		folio_put(folio);
769 		return;
770 	}
771 
772 	if (test_bit(META_dirty, &mp->flag)) {
773 		folio_mark_dirty(folio);
774 		if (test_bit(META_sync, &mp->flag)) {
775 			clear_bit(META_sync, &mp->flag);
776 			if (metapage_write_one(folio))
777 				jfs_error(mp->sb, "metapage_write_one() failed\n");
778 			folio_lock(folio);
779 		}
780 	} else if (mp->lsn)	/* discard_metapage doesn't remove it */
781 		remove_from_logsync(mp);
782 
783 	/* Try to keep metapages from using up too much memory */
784 	drop_metapage(folio, mp);
785 
786 	folio_unlock(folio);
787 	folio_put(folio);
788 }
789 
790 void __invalidate_metapages(struct inode *ip, s64 addr, int len)
791 {
792 	sector_t lblock;
793 	int l2BlocksPerPage = PAGE_SHIFT - ip->i_blkbits;
794 	int BlocksPerPage = 1 << l2BlocksPerPage;
795 	/* All callers are interested in block device's mapping */
796 	struct address_space *mapping =
797 		JFS_SBI(ip->i_sb)->direct_inode->i_mapping;
798 	struct metapage *mp;
799 	unsigned int offset;
800 
801 	/*
802 	 * Mark metapages to discard.  They will eventually be
803 	 * released, but should not be written.
804 	 */
805 	for (lblock = addr & ~(BlocksPerPage - 1); lblock < addr + len;
806 	     lblock += BlocksPerPage) {
807 		struct folio *folio = filemap_lock_folio(mapping,
808 				lblock >> l2BlocksPerPage);
809 		if (IS_ERR(folio))
810 			continue;
811 		for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
812 			mp = folio_to_mp(folio, offset);
813 			if (!mp)
814 				continue;
815 			if (mp->index < addr)
816 				continue;
817 			if (mp->index >= addr + len)
818 				break;
819 
820 			clear_bit(META_dirty, &mp->flag);
821 			set_bit(META_discard, &mp->flag);
822 			if (mp->lsn)
823 				remove_from_logsync(mp);
824 		}
825 		folio_unlock(folio);
826 		folio_put(folio);
827 	}
828 }
829 
830 #ifdef CONFIG_JFS_STATISTICS
831 int jfs_mpstat_proc_show(struct seq_file *m, void *v)
832 {
833 	seq_printf(m,
834 		       "JFS Metapage statistics\n"
835 		       "=======================\n"
836 		       "page allocations = %d\n"
837 		       "page frees = %d\n"
838 		       "lock waits = %d\n",
839 		       mpStat.pagealloc,
840 		       mpStat.pagefree,
841 		       mpStat.lockwait);
842 	return 0;
843 }
844 #endif
845