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