summaryrefslogtreecommitdiff
path: root/fs/gfs2/lops.c
blob: 3010f9edd177dffeb3e270515a15e643e37bdd22 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/mempool.h>
#include <linux/gfs2_ondisk.h>
#include <linux/bio.h>
#include <linux/fs.h>
#include <linux/list_sort.h>

#include "gfs2.h"
#include "incore.h"
#include "inode.h"
#include "glock.h"
#include "log.h"
#include "lops.h"
#include "meta_io.h"
#include "recovery.h"
#include "rgrp.h"
#include "trans.h"
#include "util.h"
#include "trace_gfs2.h"

/**
 * gfs2_pin - Pin a buffer in memory
 * @sdp: The superblock
 * @bh: The buffer to be pinned
 *
 * The log lock must be held when calling this function
 */
void gfs2_pin(struct gfs2_sbd *sdp, struct buffer_head *bh)
{
	struct gfs2_bufdata *bd;

	BUG_ON(!current->journal_info);

	clear_buffer_dirty(bh);
	if (test_set_buffer_pinned(bh))
		gfs2_assert_withdraw(sdp, 0);
	if (!buffer_uptodate(bh))
		gfs2_io_error_bh(sdp, bh);
	bd = bh->b_private;
	/* If this buffer is in the AIL and it has already been written
	 * to in-place disk block, remove it from the AIL.
	 */
	spin_lock(&sdp->sd_ail_lock);
	if (bd->bd_tr)
		list_move(&bd->bd_ail_st_list, &bd->bd_tr->tr_ail2_list);
	spin_unlock(&sdp->sd_ail_lock);
	get_bh(bh);
	atomic_inc(&sdp->sd_log_pinned);
	trace_gfs2_pin(bd, 1);
}

static bool buffer_is_rgrp(const struct gfs2_bufdata *bd)
{
	return bd->bd_gl->gl_name.ln_type == LM_TYPE_RGRP;
}

static void maybe_release_space(struct gfs2_bufdata *bd)
{
	struct gfs2_glock *gl = bd->bd_gl;
	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
	struct gfs2_rgrpd *rgd = gfs2_glock2rgrp(gl);
	unsigned int index = bd->bd_bh->b_blocknr - gl->gl_name.ln_number;
	struct gfs2_bitmap *bi = rgd->rd_bits + index;

	if (bi->bi_clone == NULL)
		return;
	if (sdp->sd_args.ar_discard)
		gfs2_rgrp_send_discards(sdp, rgd->rd_data0, bd->bd_bh, bi, 1, NULL);
	memcpy(bi->bi_clone + bi->bi_offset,
	       bd->bd_bh->b_data + bi->bi_offset, bi->bi_len);
	clear_bit(GBF_FULL, &bi->bi_flags);
	rgd->rd_free_clone = rgd->rd_free;
	rgd->rd_extfail_pt = rgd->rd_free;
}

/**
 * gfs2_unpin - Unpin a buffer
 * @sdp: the filesystem the buffer belongs to
 * @bh: The buffer to unpin
 * @ai:
 * @flags: The inode dirty flags
 *
 */

static void gfs2_unpin(struct gfs2_sbd *sdp, struct buffer_head *bh,
		       struct gfs2_trans *tr)
{
	struct gfs2_bufdata *bd = bh->b_private;

	BUG_ON(!buffer_uptodate(bh));
	BUG_ON(!buffer_pinned(bh));

	lock_buffer(bh);
	mark_buffer_dirty(bh);
	clear_buffer_pinned(bh);

	if (buffer_is_rgrp(bd))
		maybe_release_space(bd);

	spin_lock(&sdp->sd_ail_lock);
	if (bd->bd_tr) {
		list_del(&bd->bd_ail_st_list);
		brelse(bh);
	} else {
		struct gfs2_glock *gl = bd->bd_gl;
		list_add(&bd->bd_ail_gl_list, &gl->gl_ail_list);
		atomic_inc(&gl->gl_ail_count);
	}
	bd->bd_tr = tr;
	list_add(&bd->bd_ail_st_list, &tr->tr_ail1_list);
	spin_unlock(&sdp->sd_ail_lock);

	clear_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
	trace_gfs2_pin(bd, 0);
	unlock_buffer(bh);
	atomic_dec(&sdp->sd_log_pinned);
}

static void gfs2_log_incr_head(struct gfs2_sbd *sdp)
{
	BUG_ON((sdp->sd_log_flush_head == sdp->sd_log_tail) &&
	       (sdp->sd_log_flush_head != sdp->sd_log_head));

	if (++sdp->sd_log_flush_head == sdp->sd_jdesc->jd_blocks)
		sdp->sd_log_flush_head = 0;
}

static u64 gfs2_log_bmap(struct gfs2_sbd *sdp)
{
	unsigned int lbn = sdp->sd_log_flush_head;
	struct gfs2_journal_extent *je;
	u64 block;

	list_for_each_entry(je, &sdp->sd_jdesc->extent_list, list) {
		if ((lbn >= je->lblock) && (lbn < (je->lblock + je->blocks))) {
			block = je->dblock + lbn - je->lblock;
			gfs2_log_incr_head(sdp);
			return block;
		}
	}

	return -1;
}

/**
 * gfs2_end_log_write_bh - end log write of pagecache data with buffers
 * @sdp: The superblock
 * @bvec: The bio_vec
 * @error: The i/o status
 *
 * This finds the relavent buffers and unlocks then and sets the
 * error flag according to the status of the i/o request. This is
 * used when the log is writing data which has an in-place version
 * that is pinned in the pagecache.
 */

static void gfs2_end_log_write_bh(struct gfs2_sbd *sdp, struct bio_vec *bvec,
				  blk_status_t error)
{
	struct buffer_head *bh, *next;
	struct page *page = bvec->bv_page;
	unsigned size;

	bh = page_buffers(page);
	size = bvec->bv_len;
	while (bh_offset(bh) < bvec->bv_offset)
		bh = bh->b_this_page;
	do {
		if (error)
			mark_buffer_write_io_error(bh);
		unlock_buffer(bh);
		next = bh->b_this_page;
		size -= bh->b_size;
		brelse(bh);
		bh = next;
	} while(bh && size);
}

/**
 * gfs2_end_log_write - end of i/o to the log
 * @bio: The bio
 * @error: Status of i/o request
 *
 * Each bio_vec contains either data from the pagecache or data
 * relating to the log itself. Here we iterate over the bio_vec
 * array, processing both kinds of data.
 *
 */

static void gfs2_end_log_write(struct bio *bio)
{
	struct gfs2_sbd *sdp = bio->bi_private;
	struct bio_vec *bvec;
	struct page *page;
	int i;

	if (bio->bi_status)
		fs_err(sdp, "Error %d writing to log\n", bio->bi_status);

	bio_for_each_segment_all(bvec, bio, i) {
		page = bvec->bv_page;
		if (page_has_buffers(page))
			gfs2_end_log_write_bh(sdp, bvec, bio->bi_status);
		else
			mempool_free(page, gfs2_page_pool);
	}

	bio_put(bio);
	if (atomic_dec_and_test(&sdp->sd_log_in_flight))
		wake_up(&sdp->sd_log_flush_wait);
}

/**
 * gfs2_log_flush_bio - Submit any pending log bio
 * @sdp: The superblock
 * @op: REQ_OP
 * @op_flags: req_flag_bits
 *
 * Submit any pending part-built or full bio to the block device. If
 * there is no pending bio, then this is a no-op.
 */

void gfs2_log_flush_bio(struct gfs2_sbd *sdp, int op, int op_flags)
{
	if (sdp->sd_log_bio) {
		atomic_inc(&sdp->sd_log_in_flight);
		bio_set_op_attrs(sdp->sd_log_bio, op, op_flags);
		submit_bio(sdp->sd_log_bio);
		sdp->sd_log_bio = NULL;
	}
}

/**
 * gfs2_log_alloc_bio - Allocate a new bio for log writing
 * @sdp: The superblock
 * @blkno: The next device block number we want to write to
 *
 * This should never be called when there is a cached bio in the
 * super block. When it returns, there will be a cached bio in the
 * super block which will have as many bio_vecs as the device is
 * happy to handle.
 *
 * Returns: Newly allocated bio
 */

static struct bio *gfs2_log_alloc_bio(struct gfs2_sbd *sdp, u64 blkno)
{
	struct super_block *sb = sdp->sd_vfs;
	struct bio *bio;

	BUG_ON(sdp->sd_log_bio);

	bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
	bio->bi_iter.bi_sector = blkno * (sb->s_blocksize >> 9);
	bio->bi_bdev = sb->s_bdev;
	bio->bi_end_io = gfs2_end_log_write;
	bio->bi_private = sdp;

	sdp->sd_log_bio = bio;

	return bio;
}

/**
 * gfs2_log_get_bio - Get cached log bio, or allocate a new one
 * @sdp: The superblock
 * @blkno: The device block number we want to write to
 *
 * If there is a cached bio, then if the next block number is sequential
 * with the previous one, return it, otherwise flush the bio to the
 * device. If there is not a cached bio, or we just flushed it, then
 * allocate a new one.
 *
 * Returns: The bio to use for log writes
 */

static struct bio *gfs2_log_get_bio(struct gfs2_sbd *sdp, u64 blkno)
{
	struct bio *bio = sdp->sd_log_bio;
	u64 nblk;

	if (bio) {
		nblk = bio_end_sector(bio);
		nblk >>= sdp->sd_fsb2bb_shift;
		if (blkno == nblk)
			return bio;
		gfs2_log_flush_bio(sdp, REQ_OP_WRITE, 0);
	}

	return gfs2_log_alloc_bio(sdp, blkno);
}


/**
 * gfs2_log_write - write to log
 * @sdp: the filesystem
 * @page: the page to write
 * @size: the size of the data to write
 * @offset: the offset within the page 
 *
 * Try and add the page segment to the current bio. If that fails,
 * submit the current bio to the device and create a new one, and
 * then add the page segment to that.
 */

static void gfs2_log_write(struct gfs2_sbd *sdp, struct page *page,
			   unsigned size, unsigned offset)
{
	u64 blkno = gfs2_log_bmap(sdp);
	struct bio *bio;
	int ret;

	bio = gfs2_log_get_bio(sdp, blkno);
	ret = bio_add_page(bio, page, size, offset);
	if (ret == 0) {
		gfs2_log_flush_bio(sdp, REQ_OP_WRITE, 0);
		bio = gfs2_log_alloc_bio(sdp, blkno);
		ret = bio_add_page(bio, page, size, offset);
		WARN_ON(ret == 0);
	}
}

/**
 * gfs2_log_write_bh - write a buffer's content to the log
 * @sdp: The super block
 * @bh: The buffer pointing to the in-place location
 * 
 * This writes the content of the buffer to the next available location
 * in the log. The buffer will be unlocked once the i/o to the log has
 * completed.
 */

static void gfs2_log_write_bh(struct gfs2_sbd *sdp, struct buffer_head *bh)
{
	gfs2_log_write(sdp, bh->b_page, bh->b_size, bh_offset(bh));
}

/**
 * gfs2_log_write_page - write one block stored in a page, into the log
 * @sdp: The superblock
 * @page: The struct page
 *
 * This writes the first block-sized part of the page into the log. Note
 * that the page must have been allocated from the gfs2_page_pool mempool
 * and that after this has been called, ownership has been transferred and
 * the page may be freed at any time.
 */

void gfs2_log_write_page(struct gfs2_sbd *sdp, struct page *page)
{
	struct super_block *sb = sdp->sd_vfs;
	gfs2_log_write(sdp, page, sb->s_blocksize, 0);
}

static struct page *gfs2_get_log_desc(struct gfs2_sbd *sdp, u32 ld_type,
				      u32 ld_length, u32 ld_data1)
{
	struct page *page = mempool_alloc(gfs2_page_pool, GFP_NOIO);
	struct gfs2_log_descriptor *ld = page_address(page);
	clear_page(ld);
	ld->ld_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
	ld->ld_header.mh_type = cpu_to_be32(GFS2_METATYPE_LD);
	ld->ld_header.mh_format = cpu_to_be32(GFS2_FORMAT_LD);
	ld->ld_type = cpu_to_be32(ld_type);
	ld->ld_length = cpu_to_be32(ld_length);
	ld->ld_data1 = cpu_to_be32(ld_data1);
	ld->ld_data2 = 0;
	return page;
}

static void gfs2_check_magic(struct buffer_head *bh)
{
	void *kaddr;
	__be32 *ptr;

	clear_buffer_escaped(bh);
	kaddr = kmap_atomic(bh->b_page);
	ptr = kaddr + bh_offset(bh);
	if (*ptr == cpu_to_be32(GFS2_MAGIC))
		set_buffer_escaped(bh);
	kunmap_atomic(kaddr);
}

static int blocknr_cmp(void *priv, struct list_head *a, struct list_head *b)
{
	struct gfs2_bufdata *bda, *bdb;

	bda = list_entry(a, struct gfs2_bufdata, bd_list);
	bdb = list_entry(b, struct gfs2_bufdata, bd_list);

	if (bda->bd_bh->b_blocknr < bdb->bd_bh->b_blocknr)
		return -1;
	if (bda->bd_bh->b_blocknr > bdb->bd_bh->b_blocknr)
		return 1;
	return 0;
}

static void gfs2_before_commit(struct gfs2_sbd *sdp, unsigned int limit,
				unsigned int total, struct list_head *blist,
				bool is_databuf)
{
	struct gfs2_log_descriptor *ld;
	struct gfs2_bufdata *bd1 = NULL, *bd2;
	struct page *page;
	unsigned int num;
	unsigned n;
	__be64 *ptr;

	gfs2_log_lock(sdp);
	list_sort(NULL, blist, blocknr_cmp);
	bd1 = bd2 = list_prepare_entry(bd1, blist, bd_list);
	while(total) {
		num = total;
		if (total > limit)
			num = limit;
		gfs2_log_unlock(sdp);
		page = gfs2_get_log_desc(sdp,
					 is_databuf ? GFS2_LOG_DESC_JDATA :
					 GFS2_LOG_DESC_METADATA, num + 1, num);
		ld = page_address(page);
		gfs2_log_lock(sdp);
		ptr = (__be64 *)(ld + 1);

		n = 0;
		list_for_each_entry_continue(bd1, blist, bd_list) {
			*ptr++ = cpu_to_be64(bd1->bd_bh->b_blocknr);
			if (is_databuf) {
				gfs2_check_magic(bd1->bd_bh);
				*ptr++ = cpu_to_be64(buffer_escaped(bd1->bd_bh) ? 1 : 0);
			}
			if (++n >= num)
				break;
		}

		gfs2_log_unlock(sdp);
		gfs2_log_write_page(sdp, page);
		gfs2_log_lock(sdp);

		n = 0;
		list_for_each_entry_continue(bd2, blist, bd_list) {
			get_bh(bd2->bd_bh);
			gfs2_log_unlock(sdp);
			lock_buffer(bd2->bd_bh);

			if (buffer_escaped(bd2->bd_bh)) {
				void *kaddr;
				page = mempool_alloc(gfs2_page_pool, GFP_NOIO);
				ptr = page_address(page);
				kaddr = kmap_atomic(bd2->bd_bh->b_page);
				memcpy(ptr, kaddr + bh_offset(bd2->bd_bh),
				       bd2->bd_bh->b_size);
				kunmap_atomic(kaddr);
				*(__be32 *)ptr = 0;
				clear_buffer_escaped(bd2->bd_bh);
				unlock_buffer(bd2->bd_bh);
				brelse(bd2->bd_bh);
				gfs2_log_write_page(sdp, page);
			} else {
				gfs2_log_write_bh(sdp, bd2->bd_bh);
			}
			gfs2_log_lock(sdp);
			if (++n >= num)
				break;
		}

		BUG_ON(total < num);
		total -= num;
	}
	gfs2_log_unlock(sdp);
}

static void buf_lo_before_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
{
	unsigned int limit = buf_limit(sdp); /* 503 for 4k blocks */
	unsigned int nbuf;
	if (tr == NULL)
		return;
	nbuf = tr->tr_num_buf_new - tr->tr_num_buf_rm;
	gfs2_before_commit(sdp, limit, nbuf, &tr->tr_buf, 0);
}

static void buf_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
{
	struct list_head *head;
	struct gfs2_bufdata *bd;

	if (tr == NULL)
		return;

	head = &tr->tr_buf;
	while (!list_empty(head)) {
		bd = list_entry(head->next, struct gfs2_bufdata, bd_list);
		list_del_init(&bd->bd_list);
		gfs2_unpin(sdp, bd->bd_bh, tr);
	}
}

static void buf_lo_before_scan(struct gfs2_jdesc *jd,
			       struct gfs2_log_header_host *head, int pass)
{
	if (pass != 0)
		return;

	jd->jd_found_blocks = 0;
	jd->jd_replayed_blocks = 0;
}

static int buf_lo_scan_elements(struct gfs2_jdesc *jd, unsigned int start,
				struct gfs2_log_descriptor *ld, __be64 *ptr,
				int pass)
{
	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
	struct gfs2_glock *gl = ip->i_gl;
	unsigned int blks = be32_to_cpu(ld->ld_data1);
	struct buffer_head *bh_log, *bh_ip;
	u64 blkno;
	int error = 0;

	if (pass != 1 || be32_to_cpu(ld->ld_type) != GFS2_LOG_DESC_METADATA)
		return 0;

	gfs2_replay_incr_blk(jd, &start);

	for (; blks; gfs2_replay_incr_blk(jd, &start), blks--) {
		blkno = be64_to_cpu(*ptr++);

		jd->jd_found_blocks++;

		if (gfs2_revoke_check(jd, blkno, start))
			continue;

		error = gfs2_replay_read_block(jd, start, &bh_log);
		if (error)
			return error;

		bh_ip = gfs2_meta_new(gl, blkno);
		memcpy(bh_ip->b_data, bh_log->b_data, bh_log->b_size);

		if (gfs2_meta_check(sdp, bh_ip))
			error = -EIO;
		else
			mark_buffer_dirty(bh_ip);

		brelse(bh_log);
		brelse(bh_ip);

		if (error)
			break;

		jd->jd_replayed_blocks++;
	}

	return error;
}

/**
 * gfs2_meta_sync - Sync all buffers associated with a glock
 * @gl: The glock
 *
 */

static void gfs2_meta_sync(struct gfs2_glock *gl)
{
	struct address_space *mapping = gfs2_glock2aspace(gl);
	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
	int error;

	if (mapping == NULL)
		mapping = &sdp->sd_aspace;

	filemap_fdatawrite(mapping);
	error = filemap_fdatawait(mapping);

	if (error)
		gfs2_io_error(gl->gl_name.ln_sbd);
}

static void buf_lo_after_scan(struct gfs2_jdesc *jd, int error, int pass)
{
	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);

	if (error) {
		gfs2_meta_sync(ip->i_gl);
		return;
	}
	if (pass != 1)
		return;

	gfs2_meta_sync(ip->i_gl);

	fs_info(sdp, "jid=%u: Replayed %u of %u blocks\n",
	        jd->jd_jid, jd->jd_replayed_blocks, jd->jd_found_blocks);
}

static void revoke_lo_before_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
{
	struct gfs2_meta_header *mh;
	unsigned int offset;
	struct list_head *head = &sdp->sd_log_le_revoke;
	struct gfs2_bufdata *bd;
	struct page *page;
	unsigned int length;

	gfs2_write_revokes(sdp);
	if (!sdp->sd_log_num_revoke)
		return;

	length = gfs2_struct2blk(sdp, sdp->sd_log_num_revoke, sizeof(u64));
	page = gfs2_get_log_desc(sdp, GFS2_LOG_DESC_REVOKE, length, sdp->sd_log_num_revoke);
	offset = sizeof(struct gfs2_log_descriptor);

	list_for_each_entry(bd, head, bd_list) {
		sdp->sd_log_num_revoke--;

		if (offset + sizeof(u64) > sdp->sd_sb.sb_bsize) {

			gfs2_log_write_page(sdp, page);
			page = mempool_alloc(gfs2_page_pool, GFP_NOIO);
			mh = page_address(page);
			clear_page(mh);
			mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
			mh->mh_type = cpu_to_be32(GFS2_METATYPE_LB);
			mh->mh_format = cpu_to_be32(GFS2_FORMAT_LB);
			offset = sizeof(struct gfs2_meta_header);
		}

		*(__be64 *)(page_address(page) + offset) = cpu_to_be64(bd->bd_blkno);
		offset += sizeof(u64);
	}
	gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);

	gfs2_log_write_page(sdp, page);
}

static void revoke_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
{
	struct list_head *head = &sdp->sd_log_le_revoke;
	struct gfs2_bufdata *bd;
	struct gfs2_glock *gl;

	while (!list_empty(head)) {
		bd = list_entry(head->next, struct gfs2_bufdata, bd_list);
		list_del_init(&bd->bd_list);
		gl = bd->bd_gl;
		atomic_dec(&gl->gl_revokes);
		clear_bit(GLF_LFLUSH, &gl->gl_flags);
		kmem_cache_free(gfs2_bufdata_cachep, bd);
	}
}

static void revoke_lo_before_scan(struct gfs2_jdesc *jd,
				  struct gfs2_log_header_host *head, int pass)
{
	if (pass != 0)
		return;

	jd->jd_found_revokes = 0;
	jd->jd_replay_tail = head->lh_tail;
}

static int revoke_lo_scan_elements(struct gfs2_jdesc *jd, unsigned int start,
				   struct gfs2_log_descriptor *ld, __be64 *ptr,
				   int pass)
{
	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
	unsigned int blks = be32_to_cpu(ld->ld_length);
	unsigned int revokes = be32_to_cpu(ld->ld_data1);
	struct buffer_head *bh;
	unsigned int offset;
	u64 blkno;
	int first = 1;
	int error;

	if (pass != 0 || be32_to_cpu(ld->ld_type) != GFS2_LOG_DESC_REVOKE)
		return 0;

	offset = sizeof(struct gfs2_log_descriptor);

	for (; blks; gfs2_replay_incr_blk(jd, &start), blks--) {
		error = gfs2_replay_read_block(jd, start, &bh);
		if (error)
			return error;

		if (!first)
			gfs2_metatype_check(sdp, bh, GFS2_METATYPE_LB);

		while (offset + sizeof(u64) <= sdp->sd_sb.sb_bsize) {
			blkno = be64_to_cpu(*(__be64 *)(bh->b_data + offset));

			error = gfs2_revoke_add(jd, blkno, start);
			if (error < 0) {
				brelse(bh);
				return error;
			}
			else if (error)
				jd->jd_found_revokes++;

			if (!--revokes)
				break;
			offset += sizeof(u64);
		}

		brelse(bh);
		offset = sizeof(struct gfs2_meta_header);
		first = 0;
	}

	return 0;
}

static void revoke_lo_after_scan(struct gfs2_jdesc *jd, int error, int pass)
{
	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);

	if (error) {
		gfs2_revoke_clean(jd);
		return;
	}
	if (pass != 1)
		return;

	fs_info(sdp, "jid=%u: Found %u revoke tags\n",
	        jd->jd_jid, jd->jd_found_revokes);

	gfs2_revoke_clean(jd);
}

/**
 * databuf_lo_before_commit - Scan the data buffers, writing as we go
 *
 */

static void databuf_lo_before_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
{
	unsigned int limit = databuf_limit(sdp);
	unsigned int nbuf;
	if (tr == NULL)
		return;
	nbuf = tr->tr_num_databuf_new - tr->tr_num_databuf_rm;
	gfs2_before_commit(sdp, limit, nbuf, &tr->tr_databuf, 1);
}

static int databuf_lo_scan_elements(struct gfs2_jdesc *jd, unsigned int start,
				    struct gfs2_log_descriptor *ld,
				    __be64 *ptr, int pass)
{
	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
	struct gfs2_glock *gl = ip->i_gl;
	unsigned int blks = be32_to_cpu(ld->ld_data1);
	struct buffer_head *bh_log, *bh_ip;
	u64 blkno;
	u64 esc;
	int error = 0;

	if (pass != 1 || be32_to_cpu(ld->ld_type) != GFS2_LOG_DESC_JDATA)
		return 0;

	gfs2_replay_incr_blk(jd, &start);
	for (; blks; gfs2_replay_incr_blk(jd, &start), blks--) {
		blkno = be64_to_cpu(*ptr++);
		esc = be64_to_cpu(*ptr++);

		jd->jd_found_blocks++;

		if (gfs2_revoke_check(jd, blkno, start))
			continue;

		error = gfs2_replay_read_block(jd, start, &bh_log);
		if (error)
			return error;

		bh_ip = gfs2_meta_new(gl, blkno);
		memcpy(bh_ip->b_data, bh_log->b_data, bh_log->b_size);

		/* Unescape */
		if (esc) {
			__be32 *eptr = (__be32 *)bh_ip->b_data;
			*eptr = cpu_to_be32(GFS2_MAGIC);
		}
		mark_buffer_dirty(bh_ip);

		brelse(bh_log);
		brelse(bh_ip);

		jd->jd_replayed_blocks++;
	}

	return error;
}

/* FIXME: sort out accounting for log blocks etc. */

static void databuf_lo_after_scan(struct gfs2_jdesc *jd, int error, int pass)
{
	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);

	if (error) {
		gfs2_meta_sync(ip->i_gl);
		return;
	}
	if (pass != 1)
		return;

	/* data sync? */
	gfs2_meta_sync(ip->i_gl);

	fs_info(sdp, "jid=%u: Replayed %u of %u data blocks\n",
		jd->jd_jid, jd->jd_replayed_blocks, jd->jd_found_blocks);
}

static void databuf_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
{
	struct list_head *head;
	struct gfs2_bufdata *bd;

	if (tr == NULL)
		return;

	head = &tr->tr_databuf;
	while (!list_empty(head)) {
		bd = list_entry(head->next, struct gfs2_bufdata, bd_list);
		list_del_init(&bd->bd_list);
		gfs2_unpin(sdp, bd->bd_bh, tr);
	}
}


const struct gfs2_log_operations gfs2_buf_lops = {
	.lo_before_commit = buf_lo_before_commit,
	.lo_after_commit = buf_lo_after_commit,
	.lo_before_scan = buf_lo_before_scan,
	.lo_scan_elements = buf_lo_scan_elements,
	.lo_after_scan = buf_lo_after_scan,
	.lo_name = "buf",
};

const struct gfs2_log_operations gfs2_revoke_lops = {
	.lo_before_commit = revoke_lo_before_commit,
	.lo_after_commit = revoke_lo_after_commit,
	.lo_before_scan = revoke_lo_before_scan,
	.lo_scan_elements = revoke_lo_scan_elements,
	.lo_after_scan = revoke_lo_after_scan,
	.lo_name = "revoke",
};

const struct gfs2_log_operations gfs2_databuf_lops = {
	.lo_before_commit = databuf_lo_before_commit,
	.lo_after_commit = databuf_lo_after_commit,
	.lo_scan_elements = databuf_lo_scan_elements,
	.lo_after_scan = databuf_lo_after_scan,
	.lo_name = "databuf",
};

const struct gfs2_log_operations *gfs2_log_ops[] = {
	&gfs2_databuf_lops,
	&gfs2_buf_lops,
	&gfs2_revoke_lops,
	NULL,
};