GFS2: Wait for unlock completion on umount
[linux-2.6.git] / fs / gfs2 / log.c
1 /*
2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
3  * Copyright (C) 2004-2007 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/crc32.h>
17 #include <linux/delay.h>
18 #include <linux/kthread.h>
19 #include <linux/freezer.h>
20 #include <linux/bio.h>
21
22 #include "gfs2.h"
23 #include "incore.h"
24 #include "bmap.h"
25 #include "glock.h"
26 #include "log.h"
27 #include "lops.h"
28 #include "meta_io.h"
29 #include "util.h"
30 #include "dir.h"
31 #include "trace_gfs2.h"
32
33 #define PULL 1
34
35 /**
36  * gfs2_struct2blk - compute stuff
37  * @sdp: the filesystem
38  * @nstruct: the number of structures
39  * @ssize: the size of the structures
40  *
41  * Compute the number of log descriptor blocks needed to hold a certain number
42  * of structures of a certain size.
43  *
44  * Returns: the number of blocks needed (minimum is always 1)
45  */
46
47 unsigned int gfs2_struct2blk(struct gfs2_sbd *sdp, unsigned int nstruct,
48                              unsigned int ssize)
49 {
50         unsigned int blks;
51         unsigned int first, second;
52
53         blks = 1;
54         first = (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_log_descriptor)) / ssize;
55
56         if (nstruct > first) {
57                 second = (sdp->sd_sb.sb_bsize -
58                           sizeof(struct gfs2_meta_header)) / ssize;
59                 blks += DIV_ROUND_UP(nstruct - first, second);
60         }
61
62         return blks;
63 }
64
65 /**
66  * gfs2_remove_from_ail - Remove an entry from the ail lists, updating counters
67  * @mapping: The associated mapping (maybe NULL)
68  * @bd: The gfs2_bufdata to remove
69  *
70  * The log lock _must_ be held when calling this function
71  *
72  */
73
74 void gfs2_remove_from_ail(struct gfs2_bufdata *bd)
75 {
76         bd->bd_ail = NULL;
77         list_del_init(&bd->bd_ail_st_list);
78         list_del_init(&bd->bd_ail_gl_list);
79         atomic_dec(&bd->bd_gl->gl_ail_count);
80         brelse(bd->bd_bh);
81 }
82
83 /**
84  * gfs2_ail1_start_one - Start I/O on a part of the AIL
85  * @sdp: the filesystem
86  * @tr: the part of the AIL
87  *
88  */
89
90 static void gfs2_ail1_start_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
91 __releases(&sdp->sd_log_lock)
92 __acquires(&sdp->sd_log_lock)
93 {
94         struct gfs2_bufdata *bd, *s;
95         struct buffer_head *bh;
96         int retry;
97
98         do {
99                 retry = 0;
100
101                 list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list,
102                                                  bd_ail_st_list) {
103                         bh = bd->bd_bh;
104
105                         gfs2_assert(sdp, bd->bd_ail == ai);
106
107                         if (!buffer_busy(bh)) {
108                                 if (!buffer_uptodate(bh))
109                                         gfs2_io_error_bh(sdp, bh);
110                                 list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list);
111                                 continue;
112                         }
113
114                         if (!buffer_dirty(bh))
115                                 continue;
116
117                         list_move(&bd->bd_ail_st_list, &ai->ai_ail1_list);
118
119                         get_bh(bh);
120                         gfs2_log_unlock(sdp);
121                         lock_buffer(bh);
122                         if (test_clear_buffer_dirty(bh)) {
123                                 bh->b_end_io = end_buffer_write_sync;
124                                 submit_bh(WRITE_SYNC_PLUG, bh);
125                         } else {
126                                 unlock_buffer(bh);
127                                 brelse(bh);
128                         }
129                         gfs2_log_lock(sdp);
130
131                         retry = 1;
132                         break;
133                 }
134         } while (retry);
135 }
136
137 /**
138  * gfs2_ail1_empty_one - Check whether or not a trans in the AIL has been synced
139  * @sdp: the filesystem
140  * @ai: the AIL entry
141  *
142  */
143
144 static int gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai, int flags)
145 {
146         struct gfs2_bufdata *bd, *s;
147         struct buffer_head *bh;
148
149         list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list,
150                                          bd_ail_st_list) {
151                 bh = bd->bd_bh;
152
153                 gfs2_assert(sdp, bd->bd_ail == ai);
154
155                 if (buffer_busy(bh)) {
156                         if (flags & DIO_ALL)
157                                 continue;
158                         else
159                                 break;
160                 }
161
162                 if (!buffer_uptodate(bh))
163                         gfs2_io_error_bh(sdp, bh);
164
165                 list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list);
166         }
167
168         return list_empty(&ai->ai_ail1_list);
169 }
170
171 static void gfs2_ail1_start(struct gfs2_sbd *sdp, int flags)
172 {
173         struct list_head *head;
174         u64 sync_gen;
175         struct list_head *first;
176         struct gfs2_ail *first_ai, *ai, *tmp;
177         int done = 0;
178
179         gfs2_log_lock(sdp);
180         head = &sdp->sd_ail1_list;
181         if (list_empty(head)) {
182                 gfs2_log_unlock(sdp);
183                 return;
184         }
185         sync_gen = sdp->sd_ail_sync_gen++;
186
187         first = head->prev;
188         first_ai = list_entry(first, struct gfs2_ail, ai_list);
189         first_ai->ai_sync_gen = sync_gen;
190         gfs2_ail1_start_one(sdp, first_ai); /* This may drop log lock */
191
192         if (flags & DIO_ALL)
193                 first = NULL;
194
195         while(!done) {
196                 if (first && (head->prev != first ||
197                               gfs2_ail1_empty_one(sdp, first_ai, 0)))
198                         break;
199
200                 done = 1;
201                 list_for_each_entry_safe_reverse(ai, tmp, head, ai_list) {
202                         if (ai->ai_sync_gen >= sync_gen)
203                                 continue;
204                         ai->ai_sync_gen = sync_gen;
205                         gfs2_ail1_start_one(sdp, ai); /* This may drop log lock */
206                         done = 0;
207                         break;
208                 }
209         }
210
211         gfs2_log_unlock(sdp);
212 }
213
214 static int gfs2_ail1_empty(struct gfs2_sbd *sdp, int flags)
215 {
216         struct gfs2_ail *ai, *s;
217         int ret;
218
219         gfs2_log_lock(sdp);
220
221         list_for_each_entry_safe_reverse(ai, s, &sdp->sd_ail1_list, ai_list) {
222                 if (gfs2_ail1_empty_one(sdp, ai, flags))
223                         list_move(&ai->ai_list, &sdp->sd_ail2_list);
224                 else if (!(flags & DIO_ALL))
225                         break;
226         }
227
228         ret = list_empty(&sdp->sd_ail1_list);
229
230         gfs2_log_unlock(sdp);
231
232         return ret;
233 }
234
235
236 /**
237  * gfs2_ail2_empty_one - Check whether or not a trans in the AIL has been synced
238  * @sdp: the filesystem
239  * @ai: the AIL entry
240  *
241  */
242
243 static void gfs2_ail2_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
244 {
245         struct list_head *head = &ai->ai_ail2_list;
246         struct gfs2_bufdata *bd;
247
248         while (!list_empty(head)) {
249                 bd = list_entry(head->prev, struct gfs2_bufdata,
250                                 bd_ail_st_list);
251                 gfs2_assert(sdp, bd->bd_ail == ai);
252                 gfs2_remove_from_ail(bd);
253         }
254 }
255
256 static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
257 {
258         struct gfs2_ail *ai, *safe;
259         unsigned int old_tail = sdp->sd_log_tail;
260         int wrap = (new_tail < old_tail);
261         int a, b, rm;
262
263         gfs2_log_lock(sdp);
264
265         list_for_each_entry_safe(ai, safe, &sdp->sd_ail2_list, ai_list) {
266                 a = (old_tail <= ai->ai_first);
267                 b = (ai->ai_first < new_tail);
268                 rm = (wrap) ? (a || b) : (a && b);
269                 if (!rm)
270                         continue;
271
272                 gfs2_ail2_empty_one(sdp, ai);
273                 list_del(&ai->ai_list);
274                 gfs2_assert_warn(sdp, list_empty(&ai->ai_ail1_list));
275                 gfs2_assert_warn(sdp, list_empty(&ai->ai_ail2_list));
276                 kfree(ai);
277         }
278
279         gfs2_log_unlock(sdp);
280 }
281
282 /**
283  * gfs2_log_reserve - Make a log reservation
284  * @sdp: The GFS2 superblock
285  * @blks: The number of blocks to reserve
286  *
287  * Note that we never give out the last few blocks of the journal. Thats
288  * due to the fact that there is a small number of header blocks
289  * associated with each log flush. The exact number can't be known until
290  * flush time, so we ensure that we have just enough free blocks at all
291  * times to avoid running out during a log flush.
292  *
293  * Returns: errno
294  */
295
296 int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks)
297 {
298         unsigned int try = 0;
299         unsigned reserved_blks = 6 * (4096 / sdp->sd_vfs->s_blocksize);
300
301         if (gfs2_assert_warn(sdp, blks) ||
302             gfs2_assert_warn(sdp, blks <= sdp->sd_jdesc->jd_blocks))
303                 return -EINVAL;
304
305         mutex_lock(&sdp->sd_log_reserve_mutex);
306         gfs2_log_lock(sdp);
307         while(atomic_read(&sdp->sd_log_blks_free) <= (blks + reserved_blks)) {
308                 gfs2_log_unlock(sdp);
309                 gfs2_ail1_empty(sdp, 0);
310                 gfs2_log_flush(sdp, NULL);
311
312                 if (try++)
313                         gfs2_ail1_start(sdp, 0);
314                 gfs2_log_lock(sdp);
315         }
316         atomic_sub(blks, &sdp->sd_log_blks_free);
317         trace_gfs2_log_blocks(sdp, -blks);
318         gfs2_log_unlock(sdp);
319         mutex_unlock(&sdp->sd_log_reserve_mutex);
320
321         down_read(&sdp->sd_log_flush_lock);
322
323         return 0;
324 }
325
326 /**
327  * gfs2_log_release - Release a given number of log blocks
328  * @sdp: The GFS2 superblock
329  * @blks: The number of blocks
330  *
331  */
332
333 void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks)
334 {
335
336         gfs2_log_lock(sdp);
337         atomic_add(blks, &sdp->sd_log_blks_free);
338         trace_gfs2_log_blocks(sdp, blks);
339         gfs2_assert_withdraw(sdp,
340                              atomic_read(&sdp->sd_log_blks_free) <= sdp->sd_jdesc->jd_blocks);
341         gfs2_log_unlock(sdp);
342         up_read(&sdp->sd_log_flush_lock);
343 }
344
345 static u64 log_bmap(struct gfs2_sbd *sdp, unsigned int lbn)
346 {
347         struct gfs2_journal_extent *je;
348
349         list_for_each_entry(je, &sdp->sd_jdesc->extent_list, extent_list) {
350                 if (lbn >= je->lblock && lbn < je->lblock + je->blocks)
351                         return je->dblock + lbn - je->lblock;
352         }
353
354         return -1;
355 }
356
357 /**
358  * log_distance - Compute distance between two journal blocks
359  * @sdp: The GFS2 superblock
360  * @newer: The most recent journal block of the pair
361  * @older: The older journal block of the pair
362  *
363  *   Compute the distance (in the journal direction) between two
364  *   blocks in the journal
365  *
366  * Returns: the distance in blocks
367  */
368
369 static inline unsigned int log_distance(struct gfs2_sbd *sdp, unsigned int newer,
370                                         unsigned int older)
371 {
372         int dist;
373
374         dist = newer - older;
375         if (dist < 0)
376                 dist += sdp->sd_jdesc->jd_blocks;
377
378         return dist;
379 }
380
381 /**
382  * calc_reserved - Calculate the number of blocks to reserve when
383  *                 refunding a transaction's unused buffers.
384  * @sdp: The GFS2 superblock
385  *
386  * This is complex.  We need to reserve room for all our currently used
387  * metadata buffers (e.g. normal file I/O rewriting file time stamps) and 
388  * all our journaled data buffers for journaled files (e.g. files in the 
389  * meta_fs like rindex, or files for which chattr +j was done.)
390  * If we don't reserve enough space, gfs2_log_refund and gfs2_log_flush
391  * will count it as free space (sd_log_blks_free) and corruption will follow.
392  *
393  * We can have metadata bufs and jdata bufs in the same journal.  So each
394  * type gets its own log header, for which we need to reserve a block.
395  * In fact, each type has the potential for needing more than one header 
396  * in cases where we have more buffers than will fit on a journal page.
397  * Metadata journal entries take up half the space of journaled buffer entries.
398  * Thus, metadata entries have buf_limit (502) and journaled buffers have
399  * databuf_limit (251) before they cause a wrap around.
400  *
401  * Also, we need to reserve blocks for revoke journal entries and one for an
402  * overall header for the lot.
403  *
404  * Returns: the number of blocks reserved
405  */
406 static unsigned int calc_reserved(struct gfs2_sbd *sdp)
407 {
408         unsigned int reserved = 0;
409         unsigned int mbuf_limit, metabufhdrs_needed;
410         unsigned int dbuf_limit, databufhdrs_needed;
411         unsigned int revokes = 0;
412
413         mbuf_limit = buf_limit(sdp);
414         metabufhdrs_needed = (sdp->sd_log_commited_buf +
415                               (mbuf_limit - 1)) / mbuf_limit;
416         dbuf_limit = databuf_limit(sdp);
417         databufhdrs_needed = (sdp->sd_log_commited_databuf +
418                               (dbuf_limit - 1)) / dbuf_limit;
419
420         if (sdp->sd_log_commited_revoke)
421                 revokes = gfs2_struct2blk(sdp, sdp->sd_log_commited_revoke,
422                                           sizeof(u64));
423
424         reserved = sdp->sd_log_commited_buf + metabufhdrs_needed +
425                 sdp->sd_log_commited_databuf + databufhdrs_needed +
426                 revokes;
427         /* One for the overall header */
428         if (reserved)
429                 reserved++;
430         return reserved;
431 }
432
433 static unsigned int current_tail(struct gfs2_sbd *sdp)
434 {
435         struct gfs2_ail *ai;
436         unsigned int tail;
437
438         gfs2_log_lock(sdp);
439
440         if (list_empty(&sdp->sd_ail1_list)) {
441                 tail = sdp->sd_log_head;
442         } else {
443                 ai = list_entry(sdp->sd_ail1_list.prev, struct gfs2_ail, ai_list);
444                 tail = ai->ai_first;
445         }
446
447         gfs2_log_unlock(sdp);
448
449         return tail;
450 }
451
452 void gfs2_log_incr_head(struct gfs2_sbd *sdp)
453 {
454         if (sdp->sd_log_flush_head == sdp->sd_log_tail)
455                 BUG_ON(sdp->sd_log_flush_head != sdp->sd_log_head);
456
457         if (++sdp->sd_log_flush_head == sdp->sd_jdesc->jd_blocks) {
458                 sdp->sd_log_flush_head = 0;
459                 sdp->sd_log_flush_wrapped = 1;
460         }
461 }
462
463 /**
464  * gfs2_log_write_endio - End of I/O for a log buffer
465  * @bh: The buffer head
466  * @uptodate: I/O Status
467  *
468  */
469
470 static void gfs2_log_write_endio(struct buffer_head *bh, int uptodate)
471 {
472         struct gfs2_sbd *sdp = bh->b_private;
473         bh->b_private = NULL;
474
475         end_buffer_write_sync(bh, uptodate);
476         if (atomic_dec_and_test(&sdp->sd_log_in_flight))
477                 wake_up(&sdp->sd_log_flush_wait);
478 }
479
480 /**
481  * gfs2_log_get_buf - Get and initialize a buffer to use for log control data
482  * @sdp: The GFS2 superblock
483  *
484  * Returns: the buffer_head
485  */
486
487 struct buffer_head *gfs2_log_get_buf(struct gfs2_sbd *sdp)
488 {
489         u64 blkno = log_bmap(sdp, sdp->sd_log_flush_head);
490         struct buffer_head *bh;
491
492         bh = sb_getblk(sdp->sd_vfs, blkno);
493         lock_buffer(bh);
494         memset(bh->b_data, 0, bh->b_size);
495         set_buffer_uptodate(bh);
496         clear_buffer_dirty(bh);
497         gfs2_log_incr_head(sdp);
498         atomic_inc(&sdp->sd_log_in_flight);
499         bh->b_private = sdp;
500         bh->b_end_io = gfs2_log_write_endio;
501
502         return bh;
503 }
504
505 /**
506  * gfs2_fake_write_endio - 
507  * @bh: The buffer head
508  * @uptodate: The I/O Status
509  *
510  */
511
512 static void gfs2_fake_write_endio(struct buffer_head *bh, int uptodate)
513 {
514         struct buffer_head *real_bh = bh->b_private;
515         struct gfs2_bufdata *bd = real_bh->b_private;
516         struct gfs2_sbd *sdp = bd->bd_gl->gl_sbd;
517
518         end_buffer_write_sync(bh, uptodate);
519         free_buffer_head(bh);
520         unlock_buffer(real_bh);
521         brelse(real_bh);
522         if (atomic_dec_and_test(&sdp->sd_log_in_flight))
523                 wake_up(&sdp->sd_log_flush_wait);
524 }
525
526 /**
527  * gfs2_log_fake_buf - Build a fake buffer head to write metadata buffer to log
528  * @sdp: the filesystem
529  * @data: the data the buffer_head should point to
530  *
531  * Returns: the log buffer descriptor
532  */
533
534 struct buffer_head *gfs2_log_fake_buf(struct gfs2_sbd *sdp,
535                                       struct buffer_head *real)
536 {
537         u64 blkno = log_bmap(sdp, sdp->sd_log_flush_head);
538         struct buffer_head *bh;
539
540         bh = alloc_buffer_head(GFP_NOFS | __GFP_NOFAIL);
541         atomic_set(&bh->b_count, 1);
542         bh->b_state = (1 << BH_Mapped) | (1 << BH_Uptodate) | (1 << BH_Lock);
543         set_bh_page(bh, real->b_page, bh_offset(real));
544         bh->b_blocknr = blkno;
545         bh->b_size = sdp->sd_sb.sb_bsize;
546         bh->b_bdev = sdp->sd_vfs->s_bdev;
547         bh->b_private = real;
548         bh->b_end_io = gfs2_fake_write_endio;
549
550         gfs2_log_incr_head(sdp);
551         atomic_inc(&sdp->sd_log_in_flight);
552
553         return bh;
554 }
555
556 static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail)
557 {
558         unsigned int dist = log_distance(sdp, new_tail, sdp->sd_log_tail);
559
560         ail2_empty(sdp, new_tail);
561
562         gfs2_log_lock(sdp);
563         atomic_add(dist, &sdp->sd_log_blks_free);
564         trace_gfs2_log_blocks(sdp, dist);
565         gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <= sdp->sd_jdesc->jd_blocks);
566         gfs2_log_unlock(sdp);
567
568         sdp->sd_log_tail = new_tail;
569 }
570
571 /**
572  * log_write_header - Get and initialize a journal header buffer
573  * @sdp: The GFS2 superblock
574  *
575  * Returns: the initialized log buffer descriptor
576  */
577
578 static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull)
579 {
580         u64 blkno = log_bmap(sdp, sdp->sd_log_flush_head);
581         struct buffer_head *bh;
582         struct gfs2_log_header *lh;
583         unsigned int tail;
584         u32 hash;
585
586         bh = sb_getblk(sdp->sd_vfs, blkno);
587         lock_buffer(bh);
588         memset(bh->b_data, 0, bh->b_size);
589         set_buffer_uptodate(bh);
590         clear_buffer_dirty(bh);
591
592         gfs2_ail1_empty(sdp, 0);
593         tail = current_tail(sdp);
594
595         lh = (struct gfs2_log_header *)bh->b_data;
596         memset(lh, 0, sizeof(struct gfs2_log_header));
597         lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
598         lh->lh_header.mh_type = cpu_to_be32(GFS2_METATYPE_LH);
599         lh->lh_header.__pad0 = cpu_to_be64(0);
600         lh->lh_header.mh_format = cpu_to_be32(GFS2_FORMAT_LH);
601         lh->lh_header.mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
602         lh->lh_sequence = cpu_to_be64(sdp->sd_log_sequence++);
603         lh->lh_flags = cpu_to_be32(flags);
604         lh->lh_tail = cpu_to_be32(tail);
605         lh->lh_blkno = cpu_to_be32(sdp->sd_log_flush_head);
606         hash = gfs2_disk_hash(bh->b_data, sizeof(struct gfs2_log_header));
607         lh->lh_hash = cpu_to_be32(hash);
608
609         bh->b_end_io = end_buffer_write_sync;
610         if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags))
611                 goto skip_barrier;
612         get_bh(bh);
613         submit_bh(WRITE_SYNC | (1 << BIO_RW_BARRIER) | (1 << BIO_RW_META), bh);
614         wait_on_buffer(bh);
615         if (buffer_eopnotsupp(bh)) {
616                 clear_buffer_eopnotsupp(bh);
617                 set_buffer_uptodate(bh);
618                 set_bit(SDF_NOBARRIERS, &sdp->sd_flags);
619                 lock_buffer(bh);
620 skip_barrier:
621                 get_bh(bh);
622                 submit_bh(WRITE_SYNC | (1 << BIO_RW_META), bh);
623                 wait_on_buffer(bh);
624         }
625         if (!buffer_uptodate(bh))
626                 gfs2_io_error_bh(sdp, bh);
627         brelse(bh);
628
629         if (sdp->sd_log_tail != tail)
630                 log_pull_tail(sdp, tail);
631         else
632                 gfs2_assert_withdraw(sdp, !pull);
633
634         sdp->sd_log_idle = (tail == sdp->sd_log_flush_head);
635         gfs2_log_incr_head(sdp);
636 }
637
638 static void log_flush_commit(struct gfs2_sbd *sdp)
639 {
640         DEFINE_WAIT(wait);
641
642         if (atomic_read(&sdp->sd_log_in_flight)) {
643                 do {
644                         prepare_to_wait(&sdp->sd_log_flush_wait, &wait,
645                                         TASK_UNINTERRUPTIBLE);
646                         if (atomic_read(&sdp->sd_log_in_flight))
647                                 io_schedule();
648                 } while(atomic_read(&sdp->sd_log_in_flight));
649                 finish_wait(&sdp->sd_log_flush_wait, &wait);
650         }
651
652         log_write_header(sdp, 0, 0);
653 }
654
655 static void gfs2_ordered_write(struct gfs2_sbd *sdp)
656 {
657         struct gfs2_bufdata *bd;
658         struct buffer_head *bh;
659         LIST_HEAD(written);
660
661         gfs2_log_lock(sdp);
662         while (!list_empty(&sdp->sd_log_le_ordered)) {
663                 bd = list_entry(sdp->sd_log_le_ordered.next, struct gfs2_bufdata, bd_le.le_list);
664                 list_move(&bd->bd_le.le_list, &written);
665                 bh = bd->bd_bh;
666                 if (!buffer_dirty(bh))
667                         continue;
668                 get_bh(bh);
669                 gfs2_log_unlock(sdp);
670                 lock_buffer(bh);
671                 if (buffer_mapped(bh) && test_clear_buffer_dirty(bh)) {
672                         bh->b_end_io = end_buffer_write_sync;
673                         submit_bh(WRITE_SYNC_PLUG, bh);
674                 } else {
675                         unlock_buffer(bh);
676                         brelse(bh);
677                 }
678                 gfs2_log_lock(sdp);
679         }
680         list_splice(&written, &sdp->sd_log_le_ordered);
681         gfs2_log_unlock(sdp);
682 }
683
684 static void gfs2_ordered_wait(struct gfs2_sbd *sdp)
685 {
686         struct gfs2_bufdata *bd;
687         struct buffer_head *bh;
688
689         gfs2_log_lock(sdp);
690         while (!list_empty(&sdp->sd_log_le_ordered)) {
691                 bd = list_entry(sdp->sd_log_le_ordered.prev, struct gfs2_bufdata, bd_le.le_list);
692                 bh = bd->bd_bh;
693                 if (buffer_locked(bh)) {
694                         get_bh(bh);
695                         gfs2_log_unlock(sdp);
696                         wait_on_buffer(bh);
697                         brelse(bh);
698                         gfs2_log_lock(sdp);
699                         continue;
700                 }
701                 list_del_init(&bd->bd_le.le_list);
702         }
703         gfs2_log_unlock(sdp);
704 }
705
706 /**
707  * gfs2_log_flush - flush incore transaction(s)
708  * @sdp: the filesystem
709  * @gl: The glock structure to flush.  If NULL, flush the whole incore log
710  *
711  */
712
713 void __gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
714 {
715         struct gfs2_ail *ai;
716
717         down_write(&sdp->sd_log_flush_lock);
718
719         /* Log might have been flushed while we waited for the flush lock */
720         if (gl && !test_bit(GLF_LFLUSH, &gl->gl_flags)) {
721                 up_write(&sdp->sd_log_flush_lock);
722                 return;
723         }
724         trace_gfs2_log_flush(sdp, 1);
725
726         ai = kzalloc(sizeof(struct gfs2_ail), GFP_NOFS | __GFP_NOFAIL);
727         INIT_LIST_HEAD(&ai->ai_ail1_list);
728         INIT_LIST_HEAD(&ai->ai_ail2_list);
729
730         if (sdp->sd_log_num_buf != sdp->sd_log_commited_buf) {
731                 printk(KERN_INFO "GFS2: log buf %u %u\n", sdp->sd_log_num_buf,
732                        sdp->sd_log_commited_buf);
733                 gfs2_assert_withdraw(sdp, 0);
734         }
735         if (sdp->sd_log_num_databuf != sdp->sd_log_commited_databuf) {
736                 printk(KERN_INFO "GFS2: log databuf %u %u\n",
737                        sdp->sd_log_num_databuf, sdp->sd_log_commited_databuf);
738                 gfs2_assert_withdraw(sdp, 0);
739         }
740         gfs2_assert_withdraw(sdp,
741                         sdp->sd_log_num_revoke == sdp->sd_log_commited_revoke);
742
743         sdp->sd_log_flush_head = sdp->sd_log_head;
744         sdp->sd_log_flush_wrapped = 0;
745         ai->ai_first = sdp->sd_log_flush_head;
746
747         gfs2_ordered_write(sdp);
748         lops_before_commit(sdp);
749         gfs2_ordered_wait(sdp);
750
751         if (sdp->sd_log_head != sdp->sd_log_flush_head)
752                 log_flush_commit(sdp);
753         else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle){
754                 gfs2_log_lock(sdp);
755                 atomic_dec(&sdp->sd_log_blks_free); /* Adjust for unreserved buffer */
756                 trace_gfs2_log_blocks(sdp, -1);
757                 gfs2_log_unlock(sdp);
758                 log_write_header(sdp, 0, PULL);
759         }
760         lops_after_commit(sdp, ai);
761
762         gfs2_log_lock(sdp);
763         sdp->sd_log_head = sdp->sd_log_flush_head;
764         sdp->sd_log_blks_reserved = 0;
765         sdp->sd_log_commited_buf = 0;
766         sdp->sd_log_commited_databuf = 0;
767         sdp->sd_log_commited_revoke = 0;
768
769         if (!list_empty(&ai->ai_ail1_list)) {
770                 list_add(&ai->ai_list, &sdp->sd_ail1_list);
771                 ai = NULL;
772         }
773         gfs2_log_unlock(sdp);
774         trace_gfs2_log_flush(sdp, 0);
775         up_write(&sdp->sd_log_flush_lock);
776
777         kfree(ai);
778 }
779
780 static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
781 {
782         unsigned int reserved;
783         unsigned int unused;
784
785         gfs2_log_lock(sdp);
786
787         sdp->sd_log_commited_buf += tr->tr_num_buf_new - tr->tr_num_buf_rm;
788         sdp->sd_log_commited_databuf += tr->tr_num_databuf_new -
789                 tr->tr_num_databuf_rm;
790         gfs2_assert_withdraw(sdp, (((int)sdp->sd_log_commited_buf) >= 0) ||
791                              (((int)sdp->sd_log_commited_databuf) >= 0));
792         sdp->sd_log_commited_revoke += tr->tr_num_revoke - tr->tr_num_revoke_rm;
793         gfs2_assert_withdraw(sdp, ((int)sdp->sd_log_commited_revoke) >= 0);
794         reserved = calc_reserved(sdp);
795         gfs2_assert_withdraw(sdp, sdp->sd_log_blks_reserved + tr->tr_reserved >= reserved);
796         unused = sdp->sd_log_blks_reserved - reserved + tr->tr_reserved;
797         atomic_add(unused, &sdp->sd_log_blks_free);
798         trace_gfs2_log_blocks(sdp, unused);
799         gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
800                              sdp->sd_jdesc->jd_blocks);
801         sdp->sd_log_blks_reserved = reserved;
802
803         gfs2_log_unlock(sdp);
804 }
805
806 static void buf_lo_incore_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
807 {
808         struct list_head *head = &tr->tr_list_buf;
809         struct gfs2_bufdata *bd;
810
811         gfs2_log_lock(sdp);
812         while (!list_empty(head)) {
813                 bd = list_entry(head->next, struct gfs2_bufdata, bd_list_tr);
814                 list_del_init(&bd->bd_list_tr);
815                 tr->tr_num_buf--;
816         }
817         gfs2_log_unlock(sdp);
818         gfs2_assert_warn(sdp, !tr->tr_num_buf);
819 }
820
821 /**
822  * gfs2_log_commit - Commit a transaction to the log
823  * @sdp: the filesystem
824  * @tr: the transaction
825  *
826  * Returns: errno
827  */
828
829 void gfs2_log_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
830 {
831         log_refund(sdp, tr);
832         buf_lo_incore_commit(sdp, tr);
833
834         up_read(&sdp->sd_log_flush_lock);
835
836         gfs2_log_lock(sdp);
837         if (sdp->sd_log_num_buf > gfs2_tune_get(sdp, gt_incore_log_blocks))
838                 wake_up_process(sdp->sd_logd_process);
839         gfs2_log_unlock(sdp);
840 }
841
842 /**
843  * gfs2_log_shutdown - write a shutdown header into a journal
844  * @sdp: the filesystem
845  *
846  */
847
848 void gfs2_log_shutdown(struct gfs2_sbd *sdp)
849 {
850         down_write(&sdp->sd_log_flush_lock);
851
852         gfs2_assert_withdraw(sdp, !sdp->sd_log_blks_reserved);
853         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_buf);
854         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
855         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_rg);
856         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_databuf);
857         gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail1_list));
858
859         sdp->sd_log_flush_head = sdp->sd_log_head;
860         sdp->sd_log_flush_wrapped = 0;
861
862         log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT,
863                          (sdp->sd_log_tail == current_tail(sdp)) ? 0 : PULL);
864
865         gfs2_assert_warn(sdp, atomic_read(&sdp->sd_log_blks_free) == sdp->sd_jdesc->jd_blocks);
866         gfs2_assert_warn(sdp, sdp->sd_log_head == sdp->sd_log_tail);
867         gfs2_assert_warn(sdp, list_empty(&sdp->sd_ail2_list));
868
869         sdp->sd_log_head = sdp->sd_log_flush_head;
870         sdp->sd_log_tail = sdp->sd_log_head;
871
872         up_write(&sdp->sd_log_flush_lock);
873 }
874
875
876 /**
877  * gfs2_meta_syncfs - sync all the buffers in a filesystem
878  * @sdp: the filesystem
879  *
880  */
881
882 void gfs2_meta_syncfs(struct gfs2_sbd *sdp)
883 {
884         gfs2_log_flush(sdp, NULL);
885         for (;;) {
886                 gfs2_ail1_start(sdp, DIO_ALL);
887                 if (gfs2_ail1_empty(sdp, DIO_ALL))
888                         break;
889                 msleep(10);
890         }
891 }
892
893
894 /**
895  * gfs2_logd - Update log tail as Active Items get flushed to in-place blocks
896  * @sdp: Pointer to GFS2 superblock
897  *
898  * Also, periodically check to make sure that we're using the most recent
899  * journal index.
900  */
901
902 int gfs2_logd(void *data)
903 {
904         struct gfs2_sbd *sdp = data;
905         unsigned long t;
906         int need_flush;
907
908         while (!kthread_should_stop()) {
909                 /* Advance the log tail */
910
911                 t = sdp->sd_log_flush_time +
912                     gfs2_tune_get(sdp, gt_log_flush_secs) * HZ;
913
914                 gfs2_ail1_empty(sdp, DIO_ALL);
915                 gfs2_log_lock(sdp);
916                 need_flush = sdp->sd_log_num_buf > gfs2_tune_get(sdp, gt_incore_log_blocks);
917                 gfs2_log_unlock(sdp);
918                 if (need_flush || time_after_eq(jiffies, t)) {
919                         gfs2_log_flush(sdp, NULL);
920                         sdp->sd_log_flush_time = jiffies;
921                 }
922
923                 t = gfs2_tune_get(sdp, gt_logd_secs) * HZ;
924                 if (freezing(current))
925                         refrigerator();
926                 schedule_timeout_interruptible(t);
927         }
928
929         return 0;
930 }
931