xref: /openbmc/linux/fs/gfs2/lops.c (revision bc015cb8)
1 /*
2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
3  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
4  *
5  * This copyrighted material is made available to anyone wishing to use,
6  * modify, copy, or redistribute it subject to the terms and conditions
7  * of the GNU General Public License version 2.
8  */
9 
10 #include <linux/sched.h>
11 #include <linux/slab.h>
12 #include <linux/spinlock.h>
13 #include <linux/completion.h>
14 #include <linux/buffer_head.h>
15 #include <linux/gfs2_ondisk.h>
16 #include <linux/bio.h>
17 #include <linux/fs.h>
18 
19 #include "gfs2.h"
20 #include "incore.h"
21 #include "inode.h"
22 #include "glock.h"
23 #include "log.h"
24 #include "lops.h"
25 #include "meta_io.h"
26 #include "recovery.h"
27 #include "rgrp.h"
28 #include "trans.h"
29 #include "util.h"
30 #include "trace_gfs2.h"
31 
32 /**
33  * gfs2_pin - Pin a buffer in memory
34  * @sdp: The superblock
35  * @bh: The buffer to be pinned
36  *
37  * The log lock must be held when calling this function
38  */
39 static void gfs2_pin(struct gfs2_sbd *sdp, struct buffer_head *bh)
40 {
41 	struct gfs2_bufdata *bd;
42 
43 	gfs2_assert_withdraw(sdp, test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags));
44 
45 	clear_buffer_dirty(bh);
46 	if (test_set_buffer_pinned(bh))
47 		gfs2_assert_withdraw(sdp, 0);
48 	if (!buffer_uptodate(bh))
49 		gfs2_io_error_bh(sdp, bh);
50 	bd = bh->b_private;
51 	/* If this buffer is in the AIL and it has already been written
52 	 * to in-place disk block, remove it from the AIL.
53 	 */
54 	if (bd->bd_ail)
55 		list_move(&bd->bd_ail_st_list, &bd->bd_ail->ai_ail2_list);
56 	get_bh(bh);
57 	atomic_inc(&sdp->sd_log_pinned);
58 	trace_gfs2_pin(bd, 1);
59 }
60 
61 /**
62  * gfs2_unpin - Unpin a buffer
63  * @sdp: the filesystem the buffer belongs to
64  * @bh: The buffer to unpin
65  * @ai:
66  *
67  */
68 
69 static void gfs2_unpin(struct gfs2_sbd *sdp, struct buffer_head *bh,
70 		       struct gfs2_ail *ai)
71 {
72 	struct gfs2_bufdata *bd = bh->b_private;
73 
74 	gfs2_assert_withdraw(sdp, buffer_uptodate(bh));
75 
76 	if (!buffer_pinned(bh))
77 		gfs2_assert_withdraw(sdp, 0);
78 
79 	lock_buffer(bh);
80 	mark_buffer_dirty(bh);
81 	clear_buffer_pinned(bh);
82 
83 	gfs2_log_lock(sdp);
84 	if (bd->bd_ail) {
85 		list_del(&bd->bd_ail_st_list);
86 		brelse(bh);
87 	} else {
88 		struct gfs2_glock *gl = bd->bd_gl;
89 		list_add(&bd->bd_ail_gl_list, &gl->gl_ail_list);
90 		atomic_inc(&gl->gl_ail_count);
91 	}
92 	bd->bd_ail = ai;
93 	list_add(&bd->bd_ail_st_list, &ai->ai_ail1_list);
94 	if (test_and_clear_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags))
95 		gfs2_glock_schedule_for_reclaim(bd->bd_gl);
96 	trace_gfs2_pin(bd, 0);
97 	gfs2_log_unlock(sdp);
98 	unlock_buffer(bh);
99 	atomic_dec(&sdp->sd_log_pinned);
100 }
101 
102 
103 static inline struct gfs2_log_descriptor *bh_log_desc(struct buffer_head *bh)
104 {
105 	return (struct gfs2_log_descriptor *)bh->b_data;
106 }
107 
108 static inline __be64 *bh_log_ptr(struct buffer_head *bh)
109 {
110 	struct gfs2_log_descriptor *ld = bh_log_desc(bh);
111 	return (__force __be64 *)(ld + 1);
112 }
113 
114 static inline __be64 *bh_ptr_end(struct buffer_head *bh)
115 {
116 	return (__force __be64 *)(bh->b_data + bh->b_size);
117 }
118 
119 
120 static struct buffer_head *gfs2_get_log_desc(struct gfs2_sbd *sdp, u32 ld_type)
121 {
122 	struct buffer_head *bh = gfs2_log_get_buf(sdp);
123 	struct gfs2_log_descriptor *ld = bh_log_desc(bh);
124 	ld->ld_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
125 	ld->ld_header.mh_type = cpu_to_be32(GFS2_METATYPE_LD);
126 	ld->ld_header.mh_format = cpu_to_be32(GFS2_FORMAT_LD);
127 	ld->ld_type = cpu_to_be32(ld_type);
128 	ld->ld_length = 0;
129 	ld->ld_data1 = 0;
130 	ld->ld_data2 = 0;
131 	memset(ld->ld_reserved, 0, sizeof(ld->ld_reserved));
132 	return bh;
133 }
134 
135 static void buf_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
136 {
137 	struct gfs2_bufdata *bd = container_of(le, struct gfs2_bufdata, bd_le);
138 	struct gfs2_meta_header *mh;
139 	struct gfs2_trans *tr;
140 
141 	lock_buffer(bd->bd_bh);
142 	gfs2_log_lock(sdp);
143 	if (!list_empty(&bd->bd_list_tr))
144 		goto out;
145 	tr = current->journal_info;
146 	tr->tr_touched = 1;
147 	tr->tr_num_buf++;
148 	list_add(&bd->bd_list_tr, &tr->tr_list_buf);
149 	if (!list_empty(&le->le_list))
150 		goto out;
151 	set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
152 	set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
153 	gfs2_meta_check(sdp, bd->bd_bh);
154 	gfs2_pin(sdp, bd->bd_bh);
155 	mh = (struct gfs2_meta_header *)bd->bd_bh->b_data;
156 	mh->__pad0 = cpu_to_be64(0);
157 	mh->mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
158 	sdp->sd_log_num_buf++;
159 	list_add(&le->le_list, &sdp->sd_log_le_buf);
160 	tr->tr_num_buf_new++;
161 out:
162 	gfs2_log_unlock(sdp);
163 	unlock_buffer(bd->bd_bh);
164 }
165 
166 static void buf_lo_before_commit(struct gfs2_sbd *sdp)
167 {
168 	struct buffer_head *bh;
169 	struct gfs2_log_descriptor *ld;
170 	struct gfs2_bufdata *bd1 = NULL, *bd2;
171 	unsigned int total;
172 	unsigned int limit;
173 	unsigned int num;
174 	unsigned n;
175 	__be64 *ptr;
176 
177 	limit = buf_limit(sdp);
178 	/* for 4k blocks, limit = 503 */
179 
180 	gfs2_log_lock(sdp);
181 	total = sdp->sd_log_num_buf;
182 	bd1 = bd2 = list_prepare_entry(bd1, &sdp->sd_log_le_buf, bd_le.le_list);
183 	while(total) {
184 		num = total;
185 		if (total > limit)
186 			num = limit;
187 		gfs2_log_unlock(sdp);
188 		bh = gfs2_get_log_desc(sdp, GFS2_LOG_DESC_METADATA);
189 		gfs2_log_lock(sdp);
190 		ld = bh_log_desc(bh);
191 		ptr = bh_log_ptr(bh);
192 		ld->ld_length = cpu_to_be32(num + 1);
193 		ld->ld_data1 = cpu_to_be32(num);
194 
195 		n = 0;
196 		list_for_each_entry_continue(bd1, &sdp->sd_log_le_buf,
197 					     bd_le.le_list) {
198 			*ptr++ = cpu_to_be64(bd1->bd_bh->b_blocknr);
199 			if (++n >= num)
200 				break;
201 		}
202 
203 		gfs2_log_unlock(sdp);
204 		submit_bh(WRITE_SYNC_PLUG, bh);
205 		gfs2_log_lock(sdp);
206 
207 		n = 0;
208 		list_for_each_entry_continue(bd2, &sdp->sd_log_le_buf,
209 					     bd_le.le_list) {
210 			get_bh(bd2->bd_bh);
211 			gfs2_log_unlock(sdp);
212 			lock_buffer(bd2->bd_bh);
213 			bh = gfs2_log_fake_buf(sdp, bd2->bd_bh);
214 			submit_bh(WRITE_SYNC_PLUG, bh);
215 			gfs2_log_lock(sdp);
216 			if (++n >= num)
217 				break;
218 		}
219 
220 		BUG_ON(total < num);
221 		total -= num;
222 	}
223 	gfs2_log_unlock(sdp);
224 }
225 
226 static void buf_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
227 {
228 	struct list_head *head = &sdp->sd_log_le_buf;
229 	struct gfs2_bufdata *bd;
230 
231 	while (!list_empty(head)) {
232 		bd = list_entry(head->next, struct gfs2_bufdata, bd_le.le_list);
233 		list_del_init(&bd->bd_le.le_list);
234 		sdp->sd_log_num_buf--;
235 
236 		gfs2_unpin(sdp, bd->bd_bh, ai);
237 	}
238 	gfs2_assert_warn(sdp, !sdp->sd_log_num_buf);
239 }
240 
241 static void buf_lo_before_scan(struct gfs2_jdesc *jd,
242 			       struct gfs2_log_header_host *head, int pass)
243 {
244 	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
245 
246 	if (pass != 0)
247 		return;
248 
249 	sdp->sd_found_blocks = 0;
250 	sdp->sd_replayed_blocks = 0;
251 }
252 
253 static int buf_lo_scan_elements(struct gfs2_jdesc *jd, unsigned int start,
254 				struct gfs2_log_descriptor *ld, __be64 *ptr,
255 				int pass)
256 {
257 	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
258 	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
259 	struct gfs2_glock *gl = ip->i_gl;
260 	unsigned int blks = be32_to_cpu(ld->ld_data1);
261 	struct buffer_head *bh_log, *bh_ip;
262 	u64 blkno;
263 	int error = 0;
264 
265 	if (pass != 1 || be32_to_cpu(ld->ld_type) != GFS2_LOG_DESC_METADATA)
266 		return 0;
267 
268 	gfs2_replay_incr_blk(sdp, &start);
269 
270 	for (; blks; gfs2_replay_incr_blk(sdp, &start), blks--) {
271 		blkno = be64_to_cpu(*ptr++);
272 
273 		sdp->sd_found_blocks++;
274 
275 		if (gfs2_revoke_check(sdp, blkno, start))
276 			continue;
277 
278 		error = gfs2_replay_read_block(jd, start, &bh_log);
279 		if (error)
280 			return error;
281 
282 		bh_ip = gfs2_meta_new(gl, blkno);
283 		memcpy(bh_ip->b_data, bh_log->b_data, bh_log->b_size);
284 
285 		if (gfs2_meta_check(sdp, bh_ip))
286 			error = -EIO;
287 		else
288 			mark_buffer_dirty(bh_ip);
289 
290 		brelse(bh_log);
291 		brelse(bh_ip);
292 
293 		if (error)
294 			break;
295 
296 		sdp->sd_replayed_blocks++;
297 	}
298 
299 	return error;
300 }
301 
302 static void buf_lo_after_scan(struct gfs2_jdesc *jd, int error, int pass)
303 {
304 	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
305 	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
306 
307 	if (error) {
308 		gfs2_meta_sync(ip->i_gl);
309 		return;
310 	}
311 	if (pass != 1)
312 		return;
313 
314 	gfs2_meta_sync(ip->i_gl);
315 
316 	fs_info(sdp, "jid=%u: Replayed %u of %u blocks\n",
317 	        jd->jd_jid, sdp->sd_replayed_blocks, sdp->sd_found_blocks);
318 }
319 
320 static void revoke_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
321 {
322 	struct gfs2_trans *tr;
323 
324 	tr = current->journal_info;
325 	tr->tr_touched = 1;
326 	tr->tr_num_revoke++;
327 	sdp->sd_log_num_revoke++;
328 	list_add(&le->le_list, &sdp->sd_log_le_revoke);
329 }
330 
331 static void revoke_lo_before_commit(struct gfs2_sbd *sdp)
332 {
333 	struct gfs2_log_descriptor *ld;
334 	struct gfs2_meta_header *mh;
335 	struct buffer_head *bh;
336 	unsigned int offset;
337 	struct list_head *head = &sdp->sd_log_le_revoke;
338 	struct gfs2_bufdata *bd;
339 
340 	if (!sdp->sd_log_num_revoke)
341 		return;
342 
343 	bh = gfs2_get_log_desc(sdp, GFS2_LOG_DESC_REVOKE);
344 	ld = bh_log_desc(bh);
345 	ld->ld_length = cpu_to_be32(gfs2_struct2blk(sdp, sdp->sd_log_num_revoke,
346 						    sizeof(u64)));
347 	ld->ld_data1 = cpu_to_be32(sdp->sd_log_num_revoke);
348 	offset = sizeof(struct gfs2_log_descriptor);
349 
350 	while (!list_empty(head)) {
351 		bd = list_entry(head->next, struct gfs2_bufdata, bd_le.le_list);
352 		list_del_init(&bd->bd_le.le_list);
353 		sdp->sd_log_num_revoke--;
354 
355 		if (offset + sizeof(u64) > sdp->sd_sb.sb_bsize) {
356 			submit_bh(WRITE_SYNC_PLUG, bh);
357 
358 			bh = gfs2_log_get_buf(sdp);
359 			mh = (struct gfs2_meta_header *)bh->b_data;
360 			mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
361 			mh->mh_type = cpu_to_be32(GFS2_METATYPE_LB);
362 			mh->mh_format = cpu_to_be32(GFS2_FORMAT_LB);
363 			offset = sizeof(struct gfs2_meta_header);
364 		}
365 
366 		*(__be64 *)(bh->b_data + offset) = cpu_to_be64(bd->bd_blkno);
367 		kmem_cache_free(gfs2_bufdata_cachep, bd);
368 
369 		offset += sizeof(u64);
370 	}
371 	gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
372 
373 	submit_bh(WRITE_SYNC_PLUG, bh);
374 }
375 
376 static void revoke_lo_before_scan(struct gfs2_jdesc *jd,
377 				  struct gfs2_log_header_host *head, int pass)
378 {
379 	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
380 
381 	if (pass != 0)
382 		return;
383 
384 	sdp->sd_found_revokes = 0;
385 	sdp->sd_replay_tail = head->lh_tail;
386 }
387 
388 static int revoke_lo_scan_elements(struct gfs2_jdesc *jd, unsigned int start,
389 				   struct gfs2_log_descriptor *ld, __be64 *ptr,
390 				   int pass)
391 {
392 	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
393 	unsigned int blks = be32_to_cpu(ld->ld_length);
394 	unsigned int revokes = be32_to_cpu(ld->ld_data1);
395 	struct buffer_head *bh;
396 	unsigned int offset;
397 	u64 blkno;
398 	int first = 1;
399 	int error;
400 
401 	if (pass != 0 || be32_to_cpu(ld->ld_type) != GFS2_LOG_DESC_REVOKE)
402 		return 0;
403 
404 	offset = sizeof(struct gfs2_log_descriptor);
405 
406 	for (; blks; gfs2_replay_incr_blk(sdp, &start), blks--) {
407 		error = gfs2_replay_read_block(jd, start, &bh);
408 		if (error)
409 			return error;
410 
411 		if (!first)
412 			gfs2_metatype_check(sdp, bh, GFS2_METATYPE_LB);
413 
414 		while (offset + sizeof(u64) <= sdp->sd_sb.sb_bsize) {
415 			blkno = be64_to_cpu(*(__be64 *)(bh->b_data + offset));
416 
417 			error = gfs2_revoke_add(sdp, blkno, start);
418 			if (error < 0) {
419 				brelse(bh);
420 				return error;
421 			}
422 			else if (error)
423 				sdp->sd_found_revokes++;
424 
425 			if (!--revokes)
426 				break;
427 			offset += sizeof(u64);
428 		}
429 
430 		brelse(bh);
431 		offset = sizeof(struct gfs2_meta_header);
432 		first = 0;
433 	}
434 
435 	return 0;
436 }
437 
438 static void revoke_lo_after_scan(struct gfs2_jdesc *jd, int error, int pass)
439 {
440 	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
441 
442 	if (error) {
443 		gfs2_revoke_clean(sdp);
444 		return;
445 	}
446 	if (pass != 1)
447 		return;
448 
449 	fs_info(sdp, "jid=%u: Found %u revoke tags\n",
450 	        jd->jd_jid, sdp->sd_found_revokes);
451 
452 	gfs2_revoke_clean(sdp);
453 }
454 
455 static void rg_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
456 {
457 	struct gfs2_rgrpd *rgd;
458 	struct gfs2_trans *tr = current->journal_info;
459 
460 	tr->tr_touched = 1;
461 
462 	rgd = container_of(le, struct gfs2_rgrpd, rd_le);
463 
464 	gfs2_log_lock(sdp);
465 	if (!list_empty(&le->le_list)){
466 		gfs2_log_unlock(sdp);
467 		return;
468 	}
469 	gfs2_rgrp_bh_hold(rgd);
470 	sdp->sd_log_num_rg++;
471 	list_add(&le->le_list, &sdp->sd_log_le_rg);
472 	gfs2_log_unlock(sdp);
473 }
474 
475 static void rg_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
476 {
477 	struct list_head *head = &sdp->sd_log_le_rg;
478 	struct gfs2_rgrpd *rgd;
479 
480 	while (!list_empty(head)) {
481 		rgd = list_entry(head->next, struct gfs2_rgrpd, rd_le.le_list);
482 		list_del_init(&rgd->rd_le.le_list);
483 		sdp->sd_log_num_rg--;
484 
485 		gfs2_rgrp_repolish_clones(rgd);
486 		gfs2_rgrp_bh_put(rgd);
487 	}
488 	gfs2_assert_warn(sdp, !sdp->sd_log_num_rg);
489 }
490 
491 /**
492  * databuf_lo_add - Add a databuf to the transaction.
493  *
494  * This is used in two distinct cases:
495  * i) In ordered write mode
496  *    We put the data buffer on a list so that we can ensure that its
497  *    synced to disk at the right time
498  * ii) In journaled data mode
499  *    We need to journal the data block in the same way as metadata in
500  *    the functions above. The difference is that here we have a tag
501  *    which is two __be64's being the block number (as per meta data)
502  *    and a flag which says whether the data block needs escaping or
503  *    not. This means we need a new log entry for each 251 or so data
504  *    blocks, which isn't an enormous overhead but twice as much as
505  *    for normal metadata blocks.
506  */
507 static void databuf_lo_add(struct gfs2_sbd *sdp, struct gfs2_log_element *le)
508 {
509 	struct gfs2_bufdata *bd = container_of(le, struct gfs2_bufdata, bd_le);
510 	struct gfs2_trans *tr = current->journal_info;
511 	struct address_space *mapping = bd->bd_bh->b_page->mapping;
512 	struct gfs2_inode *ip = GFS2_I(mapping->host);
513 
514 	lock_buffer(bd->bd_bh);
515 	gfs2_log_lock(sdp);
516 	if (tr) {
517 		if (!list_empty(&bd->bd_list_tr))
518 			goto out;
519 		tr->tr_touched = 1;
520 		if (gfs2_is_jdata(ip)) {
521 			tr->tr_num_buf++;
522 			list_add(&bd->bd_list_tr, &tr->tr_list_buf);
523 		}
524 	}
525 	if (!list_empty(&le->le_list))
526 		goto out;
527 
528 	set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
529 	set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
530 	if (gfs2_is_jdata(ip)) {
531 		gfs2_pin(sdp, bd->bd_bh);
532 		tr->tr_num_databuf_new++;
533 		sdp->sd_log_num_databuf++;
534 		list_add_tail(&le->le_list, &sdp->sd_log_le_databuf);
535 	} else {
536 		list_add_tail(&le->le_list, &sdp->sd_log_le_ordered);
537 	}
538 out:
539 	gfs2_log_unlock(sdp);
540 	unlock_buffer(bd->bd_bh);
541 }
542 
543 static void gfs2_check_magic(struct buffer_head *bh)
544 {
545 	void *kaddr;
546 	__be32 *ptr;
547 
548 	clear_buffer_escaped(bh);
549 	kaddr = kmap_atomic(bh->b_page, KM_USER0);
550 	ptr = kaddr + bh_offset(bh);
551 	if (*ptr == cpu_to_be32(GFS2_MAGIC))
552 		set_buffer_escaped(bh);
553 	kunmap_atomic(kaddr, KM_USER0);
554 }
555 
556 static void gfs2_write_blocks(struct gfs2_sbd *sdp, struct buffer_head *bh,
557 			      struct list_head *list, struct list_head *done,
558 			      unsigned int n)
559 {
560 	struct buffer_head *bh1;
561 	struct gfs2_log_descriptor *ld;
562 	struct gfs2_bufdata *bd;
563 	__be64 *ptr;
564 
565 	if (!bh)
566 		return;
567 
568 	ld = bh_log_desc(bh);
569 	ld->ld_length = cpu_to_be32(n + 1);
570 	ld->ld_data1 = cpu_to_be32(n);
571 
572 	ptr = bh_log_ptr(bh);
573 
574 	get_bh(bh);
575 	submit_bh(WRITE_SYNC_PLUG, bh);
576 	gfs2_log_lock(sdp);
577 	while(!list_empty(list)) {
578 		bd = list_entry(list->next, struct gfs2_bufdata, bd_le.le_list);
579 		list_move_tail(&bd->bd_le.le_list, done);
580 		get_bh(bd->bd_bh);
581 		while (be64_to_cpu(*ptr) != bd->bd_bh->b_blocknr) {
582 			gfs2_log_incr_head(sdp);
583 			ptr += 2;
584 		}
585 		gfs2_log_unlock(sdp);
586 		lock_buffer(bd->bd_bh);
587 		if (buffer_escaped(bd->bd_bh)) {
588 			void *kaddr;
589 			bh1 = gfs2_log_get_buf(sdp);
590 			kaddr = kmap_atomic(bd->bd_bh->b_page, KM_USER0);
591 			memcpy(bh1->b_data, kaddr + bh_offset(bd->bd_bh),
592 			       bh1->b_size);
593 			kunmap_atomic(kaddr, KM_USER0);
594 			*(__be32 *)bh1->b_data = 0;
595 			clear_buffer_escaped(bd->bd_bh);
596 			unlock_buffer(bd->bd_bh);
597 			brelse(bd->bd_bh);
598 		} else {
599 			bh1 = gfs2_log_fake_buf(sdp, bd->bd_bh);
600 		}
601 		submit_bh(WRITE_SYNC_PLUG, bh1);
602 		gfs2_log_lock(sdp);
603 		ptr += 2;
604 	}
605 	gfs2_log_unlock(sdp);
606 	brelse(bh);
607 }
608 
609 /**
610  * databuf_lo_before_commit - Scan the data buffers, writing as we go
611  *
612  */
613 
614 static void databuf_lo_before_commit(struct gfs2_sbd *sdp)
615 {
616 	struct gfs2_bufdata *bd = NULL;
617 	struct buffer_head *bh = NULL;
618 	unsigned int n = 0;
619 	__be64 *ptr = NULL, *end = NULL;
620 	LIST_HEAD(processed);
621 	LIST_HEAD(in_progress);
622 
623 	gfs2_log_lock(sdp);
624 	while (!list_empty(&sdp->sd_log_le_databuf)) {
625 		if (ptr == end) {
626 			gfs2_log_unlock(sdp);
627 			gfs2_write_blocks(sdp, bh, &in_progress, &processed, n);
628 			n = 0;
629 			bh = gfs2_get_log_desc(sdp, GFS2_LOG_DESC_JDATA);
630 			ptr = bh_log_ptr(bh);
631 			end = bh_ptr_end(bh) - 1;
632 			gfs2_log_lock(sdp);
633 			continue;
634 		}
635 		bd = list_entry(sdp->sd_log_le_databuf.next, struct gfs2_bufdata, bd_le.le_list);
636 		list_move_tail(&bd->bd_le.le_list, &in_progress);
637 		gfs2_check_magic(bd->bd_bh);
638 		*ptr++ = cpu_to_be64(bd->bd_bh->b_blocknr);
639 		*ptr++ = cpu_to_be64(buffer_escaped(bh) ? 1 : 0);
640 		n++;
641 	}
642 	gfs2_log_unlock(sdp);
643 	gfs2_write_blocks(sdp, bh, &in_progress, &processed, n);
644 	gfs2_log_lock(sdp);
645 	list_splice(&processed, &sdp->sd_log_le_databuf);
646 	gfs2_log_unlock(sdp);
647 }
648 
649 static int databuf_lo_scan_elements(struct gfs2_jdesc *jd, unsigned int start,
650 				    struct gfs2_log_descriptor *ld,
651 				    __be64 *ptr, int pass)
652 {
653 	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
654 	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
655 	struct gfs2_glock *gl = ip->i_gl;
656 	unsigned int blks = be32_to_cpu(ld->ld_data1);
657 	struct buffer_head *bh_log, *bh_ip;
658 	u64 blkno;
659 	u64 esc;
660 	int error = 0;
661 
662 	if (pass != 1 || be32_to_cpu(ld->ld_type) != GFS2_LOG_DESC_JDATA)
663 		return 0;
664 
665 	gfs2_replay_incr_blk(sdp, &start);
666 	for (; blks; gfs2_replay_incr_blk(sdp, &start), blks--) {
667 		blkno = be64_to_cpu(*ptr++);
668 		esc = be64_to_cpu(*ptr++);
669 
670 		sdp->sd_found_blocks++;
671 
672 		if (gfs2_revoke_check(sdp, blkno, start))
673 			continue;
674 
675 		error = gfs2_replay_read_block(jd, start, &bh_log);
676 		if (error)
677 			return error;
678 
679 		bh_ip = gfs2_meta_new(gl, blkno);
680 		memcpy(bh_ip->b_data, bh_log->b_data, bh_log->b_size);
681 
682 		/* Unescape */
683 		if (esc) {
684 			__be32 *eptr = (__be32 *)bh_ip->b_data;
685 			*eptr = cpu_to_be32(GFS2_MAGIC);
686 		}
687 		mark_buffer_dirty(bh_ip);
688 
689 		brelse(bh_log);
690 		brelse(bh_ip);
691 		if (error)
692 			break;
693 
694 		sdp->sd_replayed_blocks++;
695 	}
696 
697 	return error;
698 }
699 
700 /* FIXME: sort out accounting for log blocks etc. */
701 
702 static void databuf_lo_after_scan(struct gfs2_jdesc *jd, int error, int pass)
703 {
704 	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
705 	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
706 
707 	if (error) {
708 		gfs2_meta_sync(ip->i_gl);
709 		return;
710 	}
711 	if (pass != 1)
712 		return;
713 
714 	/* data sync? */
715 	gfs2_meta_sync(ip->i_gl);
716 
717 	fs_info(sdp, "jid=%u: Replayed %u of %u data blocks\n",
718 		jd->jd_jid, sdp->sd_replayed_blocks, sdp->sd_found_blocks);
719 }
720 
721 static void databuf_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
722 {
723 	struct list_head *head = &sdp->sd_log_le_databuf;
724 	struct gfs2_bufdata *bd;
725 
726 	while (!list_empty(head)) {
727 		bd = list_entry(head->next, struct gfs2_bufdata, bd_le.le_list);
728 		list_del_init(&bd->bd_le.le_list);
729 		sdp->sd_log_num_databuf--;
730 		gfs2_unpin(sdp, bd->bd_bh, ai);
731 	}
732 	gfs2_assert_warn(sdp, !sdp->sd_log_num_databuf);
733 }
734 
735 
736 const struct gfs2_log_operations gfs2_buf_lops = {
737 	.lo_add = buf_lo_add,
738 	.lo_before_commit = buf_lo_before_commit,
739 	.lo_after_commit = buf_lo_after_commit,
740 	.lo_before_scan = buf_lo_before_scan,
741 	.lo_scan_elements = buf_lo_scan_elements,
742 	.lo_after_scan = buf_lo_after_scan,
743 	.lo_name = "buf",
744 };
745 
746 const struct gfs2_log_operations gfs2_revoke_lops = {
747 	.lo_add = revoke_lo_add,
748 	.lo_before_commit = revoke_lo_before_commit,
749 	.lo_before_scan = revoke_lo_before_scan,
750 	.lo_scan_elements = revoke_lo_scan_elements,
751 	.lo_after_scan = revoke_lo_after_scan,
752 	.lo_name = "revoke",
753 };
754 
755 const struct gfs2_log_operations gfs2_rg_lops = {
756 	.lo_add = rg_lo_add,
757 	.lo_after_commit = rg_lo_after_commit,
758 	.lo_name = "rg",
759 };
760 
761 const struct gfs2_log_operations gfs2_databuf_lops = {
762 	.lo_add = databuf_lo_add,
763 	.lo_before_commit = databuf_lo_before_commit,
764 	.lo_after_commit = databuf_lo_after_commit,
765 	.lo_scan_elements = databuf_lo_scan_elements,
766 	.lo_after_scan = databuf_lo_after_scan,
767 	.lo_name = "databuf",
768 };
769 
770 const struct gfs2_log_operations *gfs2_log_ops[] = {
771 	&gfs2_databuf_lops,
772 	&gfs2_buf_lops,
773 	&gfs2_rg_lops,
774 	&gfs2_revoke_lops,
775 	NULL,
776 };
777 
778