Merge branch 'v2.6.36-rc8' into for-2.6.37/barrier
[linux-3.10.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)
172 {
173         struct list_head *head;
174         u64 sync_gen;
175         struct gfs2_ail *ai;
176         int done = 0;
177
178         gfs2_log_lock(sdp);
179         head = &sdp->sd_ail1_list;
180         if (list_empty(head)) {
181                 gfs2_log_unlock(sdp);
182                 return;
183         }
184         sync_gen = sdp->sd_ail_sync_gen++;
185
186         while(!done) {
187                 done = 1;
188                 list_for_each_entry_reverse(ai, head, ai_list) {
189                         if (ai->ai_sync_gen >= sync_gen)
190                                 continue;
191                         ai->ai_sync_gen = sync_gen;
192                         gfs2_ail1_start_one(sdp, ai); /* This may drop log lock */
193                         done = 0;
194                         break;
195                 }
196         }
197
198         gfs2_log_unlock(sdp);
199 }
200
201 static int gfs2_ail1_empty(struct gfs2_sbd *sdp, int flags)
202 {
203         struct gfs2_ail *ai, *s;
204         int ret;
205
206         gfs2_log_lock(sdp);
207
208         list_for_each_entry_safe_reverse(ai, s, &sdp->sd_ail1_list, ai_list) {
209                 if (gfs2_ail1_empty_one(sdp, ai, flags))
210                         list_move(&ai->ai_list, &sdp->sd_ail2_list);
211                 else if (!(flags & DIO_ALL))
212                         break;
213         }
214
215         ret = list_empty(&sdp->sd_ail1_list);
216
217         gfs2_log_unlock(sdp);
218
219         return ret;
220 }
221
222
223 /**
224  * gfs2_ail2_empty_one - Check whether or not a trans in the AIL has been synced
225  * @sdp: the filesystem
226  * @ai: the AIL entry
227  *
228  */
229
230 static void gfs2_ail2_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
231 {
232         struct list_head *head = &ai->ai_ail2_list;
233         struct gfs2_bufdata *bd;
234
235         while (!list_empty(head)) {
236                 bd = list_entry(head->prev, struct gfs2_bufdata,
237                                 bd_ail_st_list);
238                 gfs2_assert(sdp, bd->bd_ail == ai);
239                 gfs2_remove_from_ail(bd);
240         }
241 }
242
243 static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
244 {
245         struct gfs2_ail *ai, *safe;
246         unsigned int old_tail = sdp->sd_log_tail;
247         int wrap = (new_tail < old_tail);
248         int a, b, rm;
249
250         gfs2_log_lock(sdp);
251
252         list_for_each_entry_safe(ai, safe, &sdp->sd_ail2_list, ai_list) {
253                 a = (old_tail <= ai->ai_first);
254                 b = (ai->ai_first < new_tail);
255                 rm = (wrap) ? (a || b) : (a && b);
256                 if (!rm)
257                         continue;
258
259                 gfs2_ail2_empty_one(sdp, ai);
260                 list_del(&ai->ai_list);
261                 gfs2_assert_warn(sdp, list_empty(&ai->ai_ail1_list));
262                 gfs2_assert_warn(sdp, list_empty(&ai->ai_ail2_list));
263                 kfree(ai);
264         }
265
266         gfs2_log_unlock(sdp);
267 }
268
269 /**
270  * gfs2_log_reserve - Make a log reservation
271  * @sdp: The GFS2 superblock
272  * @blks: The number of blocks to reserve
273  *
274  * Note that we never give out the last few blocks of the journal. Thats
275  * due to the fact that there is a small number of header blocks
276  * associated with each log flush. The exact number can't be known until
277  * flush time, so we ensure that we have just enough free blocks at all
278  * times to avoid running out during a log flush.
279  *
280  * We no longer flush the log here, instead we wake up logd to do that
281  * for us. To avoid the thundering herd and to ensure that we deal fairly
282  * with queued waiters, we use an exclusive wait. This means that when we
283  * get woken with enough journal space to get our reservation, we need to
284  * wake the next waiter on the list.
285  *
286  * Returns: errno
287  */
288
289 int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks)
290 {
291         unsigned reserved_blks = 6 * (4096 / sdp->sd_vfs->s_blocksize);
292         unsigned wanted = blks + reserved_blks;
293         DEFINE_WAIT(wait);
294         int did_wait = 0;
295         unsigned int free_blocks;
296
297         if (gfs2_assert_warn(sdp, blks) ||
298             gfs2_assert_warn(sdp, blks <= sdp->sd_jdesc->jd_blocks))
299                 return -EINVAL;
300 retry:
301         free_blocks = atomic_read(&sdp->sd_log_blks_free);
302         if (unlikely(free_blocks <= wanted)) {
303                 do {
304                         prepare_to_wait_exclusive(&sdp->sd_log_waitq, &wait,
305                                         TASK_UNINTERRUPTIBLE);
306                         wake_up(&sdp->sd_logd_waitq);
307                         did_wait = 1;
308                         if (atomic_read(&sdp->sd_log_blks_free) <= wanted)
309                                 io_schedule();
310                         free_blocks = atomic_read(&sdp->sd_log_blks_free);
311                 } while(free_blocks <= wanted);
312                 finish_wait(&sdp->sd_log_waitq, &wait);
313         }
314         if (atomic_cmpxchg(&sdp->sd_log_blks_free, free_blocks,
315                                 free_blocks - blks) != free_blocks)
316                 goto retry;
317         trace_gfs2_log_blocks(sdp, -blks);
318
319         /*
320          * If we waited, then so might others, wake them up _after_ we get
321          * our share of the log.
322          */
323         if (unlikely(did_wait))
324                 wake_up(&sdp->sd_log_waitq);
325
326         down_read(&sdp->sd_log_flush_lock);
327
328         return 0;
329 }
330
331 static u64 log_bmap(struct gfs2_sbd *sdp, unsigned int lbn)
332 {
333         struct gfs2_journal_extent *je;
334
335         list_for_each_entry(je, &sdp->sd_jdesc->extent_list, extent_list) {
336                 if (lbn >= je->lblock && lbn < je->lblock + je->blocks)
337                         return je->dblock + lbn - je->lblock;
338         }
339
340         return -1;
341 }
342
343 /**
344  * log_distance - Compute distance between two journal blocks
345  * @sdp: The GFS2 superblock
346  * @newer: The most recent journal block of the pair
347  * @older: The older journal block of the pair
348  *
349  *   Compute the distance (in the journal direction) between two
350  *   blocks in the journal
351  *
352  * Returns: the distance in blocks
353  */
354
355 static inline unsigned int log_distance(struct gfs2_sbd *sdp, unsigned int newer,
356                                         unsigned int older)
357 {
358         int dist;
359
360         dist = newer - older;
361         if (dist < 0)
362                 dist += sdp->sd_jdesc->jd_blocks;
363
364         return dist;
365 }
366
367 /**
368  * calc_reserved - Calculate the number of blocks to reserve when
369  *                 refunding a transaction's unused buffers.
370  * @sdp: The GFS2 superblock
371  *
372  * This is complex.  We need to reserve room for all our currently used
373  * metadata buffers (e.g. normal file I/O rewriting file time stamps) and 
374  * all our journaled data buffers for journaled files (e.g. files in the 
375  * meta_fs like rindex, or files for which chattr +j was done.)
376  * If we don't reserve enough space, gfs2_log_refund and gfs2_log_flush
377  * will count it as free space (sd_log_blks_free) and corruption will follow.
378  *
379  * We can have metadata bufs and jdata bufs in the same journal.  So each
380  * type gets its own log header, for which we need to reserve a block.
381  * In fact, each type has the potential for needing more than one header 
382  * in cases where we have more buffers than will fit on a journal page.
383  * Metadata journal entries take up half the space of journaled buffer entries.
384  * Thus, metadata entries have buf_limit (502) and journaled buffers have
385  * databuf_limit (251) before they cause a wrap around.
386  *
387  * Also, we need to reserve blocks for revoke journal entries and one for an
388  * overall header for the lot.
389  *
390  * Returns: the number of blocks reserved
391  */
392 static unsigned int calc_reserved(struct gfs2_sbd *sdp)
393 {
394         unsigned int reserved = 0;
395         unsigned int mbuf_limit, metabufhdrs_needed;
396         unsigned int dbuf_limit, databufhdrs_needed;
397         unsigned int revokes = 0;
398
399         mbuf_limit = buf_limit(sdp);
400         metabufhdrs_needed = (sdp->sd_log_commited_buf +
401                               (mbuf_limit - 1)) / mbuf_limit;
402         dbuf_limit = databuf_limit(sdp);
403         databufhdrs_needed = (sdp->sd_log_commited_databuf +
404                               (dbuf_limit - 1)) / dbuf_limit;
405
406         if (sdp->sd_log_commited_revoke > 0)
407                 revokes = gfs2_struct2blk(sdp, sdp->sd_log_commited_revoke,
408                                           sizeof(u64));
409
410         reserved = sdp->sd_log_commited_buf + metabufhdrs_needed +
411                 sdp->sd_log_commited_databuf + databufhdrs_needed +
412                 revokes;
413         /* One for the overall header */
414         if (reserved)
415                 reserved++;
416         return reserved;
417 }
418
419 static unsigned int current_tail(struct gfs2_sbd *sdp)
420 {
421         struct gfs2_ail *ai;
422         unsigned int tail;
423
424         gfs2_log_lock(sdp);
425
426         if (list_empty(&sdp->sd_ail1_list)) {
427                 tail = sdp->sd_log_head;
428         } else {
429                 ai = list_entry(sdp->sd_ail1_list.prev, struct gfs2_ail, ai_list);
430                 tail = ai->ai_first;
431         }
432
433         gfs2_log_unlock(sdp);
434
435         return tail;
436 }
437
438 void gfs2_log_incr_head(struct gfs2_sbd *sdp)
439 {
440         if (sdp->sd_log_flush_head == sdp->sd_log_tail)
441                 BUG_ON(sdp->sd_log_flush_head != sdp->sd_log_head);
442
443         if (++sdp->sd_log_flush_head == sdp->sd_jdesc->jd_blocks) {
444                 sdp->sd_log_flush_head = 0;
445                 sdp->sd_log_flush_wrapped = 1;
446         }
447 }
448
449 /**
450  * gfs2_log_write_endio - End of I/O for a log buffer
451  * @bh: The buffer head
452  * @uptodate: I/O Status
453  *
454  */
455
456 static void gfs2_log_write_endio(struct buffer_head *bh, int uptodate)
457 {
458         struct gfs2_sbd *sdp = bh->b_private;
459         bh->b_private = NULL;
460
461         end_buffer_write_sync(bh, uptodate);
462         if (atomic_dec_and_test(&sdp->sd_log_in_flight))
463                 wake_up(&sdp->sd_log_flush_wait);
464 }
465
466 /**
467  * gfs2_log_get_buf - Get and initialize a buffer to use for log control data
468  * @sdp: The GFS2 superblock
469  *
470  * Returns: the buffer_head
471  */
472
473 struct buffer_head *gfs2_log_get_buf(struct gfs2_sbd *sdp)
474 {
475         u64 blkno = log_bmap(sdp, sdp->sd_log_flush_head);
476         struct buffer_head *bh;
477
478         bh = sb_getblk(sdp->sd_vfs, blkno);
479         lock_buffer(bh);
480         memset(bh->b_data, 0, bh->b_size);
481         set_buffer_uptodate(bh);
482         clear_buffer_dirty(bh);
483         gfs2_log_incr_head(sdp);
484         atomic_inc(&sdp->sd_log_in_flight);
485         bh->b_private = sdp;
486         bh->b_end_io = gfs2_log_write_endio;
487
488         return bh;
489 }
490
491 /**
492  * gfs2_fake_write_endio - 
493  * @bh: The buffer head
494  * @uptodate: The I/O Status
495  *
496  */
497
498 static void gfs2_fake_write_endio(struct buffer_head *bh, int uptodate)
499 {
500         struct buffer_head *real_bh = bh->b_private;
501         struct gfs2_bufdata *bd = real_bh->b_private;
502         struct gfs2_sbd *sdp = bd->bd_gl->gl_sbd;
503
504         end_buffer_write_sync(bh, uptodate);
505         free_buffer_head(bh);
506         unlock_buffer(real_bh);
507         brelse(real_bh);
508         if (atomic_dec_and_test(&sdp->sd_log_in_flight))
509                 wake_up(&sdp->sd_log_flush_wait);
510 }
511
512 /**
513  * gfs2_log_fake_buf - Build a fake buffer head to write metadata buffer to log
514  * @sdp: the filesystem
515  * @data: the data the buffer_head should point to
516  *
517  * Returns: the log buffer descriptor
518  */
519
520 struct buffer_head *gfs2_log_fake_buf(struct gfs2_sbd *sdp,
521                                       struct buffer_head *real)
522 {
523         u64 blkno = log_bmap(sdp, sdp->sd_log_flush_head);
524         struct buffer_head *bh;
525
526         bh = alloc_buffer_head(GFP_NOFS | __GFP_NOFAIL);
527         atomic_set(&bh->b_count, 1);
528         bh->b_state = (1 << BH_Mapped) | (1 << BH_Uptodate) | (1 << BH_Lock);
529         set_bh_page(bh, real->b_page, bh_offset(real));
530         bh->b_blocknr = blkno;
531         bh->b_size = sdp->sd_sb.sb_bsize;
532         bh->b_bdev = sdp->sd_vfs->s_bdev;
533         bh->b_private = real;
534         bh->b_end_io = gfs2_fake_write_endio;
535
536         gfs2_log_incr_head(sdp);
537         atomic_inc(&sdp->sd_log_in_flight);
538
539         return bh;
540 }
541
542 static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail)
543 {
544         unsigned int dist = log_distance(sdp, new_tail, sdp->sd_log_tail);
545
546         ail2_empty(sdp, new_tail);
547
548         atomic_add(dist, &sdp->sd_log_blks_free);
549         trace_gfs2_log_blocks(sdp, dist);
550         gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
551                              sdp->sd_jdesc->jd_blocks);
552
553         sdp->sd_log_tail = new_tail;
554 }
555
556 /**
557  * log_write_header - Get and initialize a journal header buffer
558  * @sdp: The GFS2 superblock
559  *
560  * Returns: the initialized log buffer descriptor
561  */
562
563 static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull)
564 {
565         u64 blkno = log_bmap(sdp, sdp->sd_log_flush_head);
566         struct buffer_head *bh;
567         struct gfs2_log_header *lh;
568         unsigned int tail;
569         u32 hash;
570
571         bh = sb_getblk(sdp->sd_vfs, blkno);
572         lock_buffer(bh);
573         memset(bh->b_data, 0, bh->b_size);
574         set_buffer_uptodate(bh);
575         clear_buffer_dirty(bh);
576
577         gfs2_ail1_empty(sdp, 0);
578         tail = current_tail(sdp);
579
580         lh = (struct gfs2_log_header *)bh->b_data;
581         memset(lh, 0, sizeof(struct gfs2_log_header));
582         lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
583         lh->lh_header.mh_type = cpu_to_be32(GFS2_METATYPE_LH);
584         lh->lh_header.__pad0 = cpu_to_be64(0);
585         lh->lh_header.mh_format = cpu_to_be32(GFS2_FORMAT_LH);
586         lh->lh_header.mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
587         lh->lh_sequence = cpu_to_be64(sdp->sd_log_sequence++);
588         lh->lh_flags = cpu_to_be32(flags);
589         lh->lh_tail = cpu_to_be32(tail);
590         lh->lh_blkno = cpu_to_be32(sdp->sd_log_flush_head);
591         hash = gfs2_disk_hash(bh->b_data, sizeof(struct gfs2_log_header));
592         lh->lh_hash = cpu_to_be32(hash);
593
594         bh->b_end_io = end_buffer_write_sync;
595         get_bh(bh);
596         if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags))
597                 submit_bh(WRITE_SYNC | REQ_META, bh);
598         else
599                 submit_bh(WRITE_FLUSH_FUA | REQ_META, bh);
600         wait_on_buffer(bh);
601
602         if (!buffer_uptodate(bh))
603                 gfs2_io_error_bh(sdp, bh);
604         brelse(bh);
605
606         if (sdp->sd_log_tail != tail)
607                 log_pull_tail(sdp, tail);
608         else
609                 gfs2_assert_withdraw(sdp, !pull);
610
611         sdp->sd_log_idle = (tail == sdp->sd_log_flush_head);
612         gfs2_log_incr_head(sdp);
613 }
614
615 static void log_flush_commit(struct gfs2_sbd *sdp)
616 {
617         DEFINE_WAIT(wait);
618
619         if (atomic_read(&sdp->sd_log_in_flight)) {
620                 do {
621                         prepare_to_wait(&sdp->sd_log_flush_wait, &wait,
622                                         TASK_UNINTERRUPTIBLE);
623                         if (atomic_read(&sdp->sd_log_in_flight))
624                                 io_schedule();
625                 } while(atomic_read(&sdp->sd_log_in_flight));
626                 finish_wait(&sdp->sd_log_flush_wait, &wait);
627         }
628
629         log_write_header(sdp, 0, 0);
630 }
631
632 static void gfs2_ordered_write(struct gfs2_sbd *sdp)
633 {
634         struct gfs2_bufdata *bd;
635         struct buffer_head *bh;
636         LIST_HEAD(written);
637
638         gfs2_log_lock(sdp);
639         while (!list_empty(&sdp->sd_log_le_ordered)) {
640                 bd = list_entry(sdp->sd_log_le_ordered.next, struct gfs2_bufdata, bd_le.le_list);
641                 list_move(&bd->bd_le.le_list, &written);
642                 bh = bd->bd_bh;
643                 if (!buffer_dirty(bh))
644                         continue;
645                 get_bh(bh);
646                 gfs2_log_unlock(sdp);
647                 lock_buffer(bh);
648                 if (buffer_mapped(bh) && test_clear_buffer_dirty(bh)) {
649                         bh->b_end_io = end_buffer_write_sync;
650                         submit_bh(WRITE_SYNC_PLUG, bh);
651                 } else {
652                         unlock_buffer(bh);
653                         brelse(bh);
654                 }
655                 gfs2_log_lock(sdp);
656         }
657         list_splice(&written, &sdp->sd_log_le_ordered);
658         gfs2_log_unlock(sdp);
659 }
660
661 static void gfs2_ordered_wait(struct gfs2_sbd *sdp)
662 {
663         struct gfs2_bufdata *bd;
664         struct buffer_head *bh;
665
666         gfs2_log_lock(sdp);
667         while (!list_empty(&sdp->sd_log_le_ordered)) {
668                 bd = list_entry(sdp->sd_log_le_ordered.prev, struct gfs2_bufdata, bd_le.le_list);
669                 bh = bd->bd_bh;
670                 if (buffer_locked(bh)) {
671                         get_bh(bh);
672                         gfs2_log_unlock(sdp);
673                         wait_on_buffer(bh);
674                         brelse(bh);
675                         gfs2_log_lock(sdp);
676                         continue;
677                 }
678                 list_del_init(&bd->bd_le.le_list);
679         }
680         gfs2_log_unlock(sdp);
681 }
682
683 /**
684  * gfs2_log_flush - flush incore transaction(s)
685  * @sdp: the filesystem
686  * @gl: The glock structure to flush.  If NULL, flush the whole incore log
687  *
688  */
689
690 void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
691 {
692         struct gfs2_ail *ai;
693
694         down_write(&sdp->sd_log_flush_lock);
695
696         /* Log might have been flushed while we waited for the flush lock */
697         if (gl && !test_bit(GLF_LFLUSH, &gl->gl_flags)) {
698                 up_write(&sdp->sd_log_flush_lock);
699                 return;
700         }
701         trace_gfs2_log_flush(sdp, 1);
702
703         ai = kzalloc(sizeof(struct gfs2_ail), GFP_NOFS | __GFP_NOFAIL);
704         INIT_LIST_HEAD(&ai->ai_ail1_list);
705         INIT_LIST_HEAD(&ai->ai_ail2_list);
706
707         if (sdp->sd_log_num_buf != sdp->sd_log_commited_buf) {
708                 printk(KERN_INFO "GFS2: log buf %u %u\n", sdp->sd_log_num_buf,
709                        sdp->sd_log_commited_buf);
710                 gfs2_assert_withdraw(sdp, 0);
711         }
712         if (sdp->sd_log_num_databuf != sdp->sd_log_commited_databuf) {
713                 printk(KERN_INFO "GFS2: log databuf %u %u\n",
714                        sdp->sd_log_num_databuf, sdp->sd_log_commited_databuf);
715                 gfs2_assert_withdraw(sdp, 0);
716         }
717         gfs2_assert_withdraw(sdp,
718                         sdp->sd_log_num_revoke == sdp->sd_log_commited_revoke);
719
720         sdp->sd_log_flush_head = sdp->sd_log_head;
721         sdp->sd_log_flush_wrapped = 0;
722         ai->ai_first = sdp->sd_log_flush_head;
723
724         gfs2_ordered_write(sdp);
725         lops_before_commit(sdp);
726         gfs2_ordered_wait(sdp);
727
728         if (sdp->sd_log_head != sdp->sd_log_flush_head)
729                 log_flush_commit(sdp);
730         else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle){
731                 gfs2_log_lock(sdp);
732                 atomic_dec(&sdp->sd_log_blks_free); /* Adjust for unreserved buffer */
733                 trace_gfs2_log_blocks(sdp, -1);
734                 gfs2_log_unlock(sdp);
735                 log_write_header(sdp, 0, PULL);
736         }
737         lops_after_commit(sdp, ai);
738
739         gfs2_log_lock(sdp);
740         sdp->sd_log_head = sdp->sd_log_flush_head;
741         sdp->sd_log_blks_reserved = 0;
742         sdp->sd_log_commited_buf = 0;
743         sdp->sd_log_commited_databuf = 0;
744         sdp->sd_log_commited_revoke = 0;
745
746         if (!list_empty(&ai->ai_ail1_list)) {
747                 list_add(&ai->ai_list, &sdp->sd_ail1_list);
748                 ai = NULL;
749         }
750         gfs2_log_unlock(sdp);
751         trace_gfs2_log_flush(sdp, 0);
752         up_write(&sdp->sd_log_flush_lock);
753
754         kfree(ai);
755 }
756
757 static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
758 {
759         unsigned int reserved;
760         unsigned int unused;
761
762         gfs2_log_lock(sdp);
763
764         sdp->sd_log_commited_buf += tr->tr_num_buf_new - tr->tr_num_buf_rm;
765         sdp->sd_log_commited_databuf += tr->tr_num_databuf_new -
766                 tr->tr_num_databuf_rm;
767         gfs2_assert_withdraw(sdp, (((int)sdp->sd_log_commited_buf) >= 0) ||
768                              (((int)sdp->sd_log_commited_databuf) >= 0));
769         sdp->sd_log_commited_revoke += tr->tr_num_revoke - tr->tr_num_revoke_rm;
770         reserved = calc_reserved(sdp);
771         gfs2_assert_withdraw(sdp, sdp->sd_log_blks_reserved + tr->tr_reserved >= reserved);
772         unused = sdp->sd_log_blks_reserved - reserved + tr->tr_reserved;
773         atomic_add(unused, &sdp->sd_log_blks_free);
774         trace_gfs2_log_blocks(sdp, unused);
775         gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
776                              sdp->sd_jdesc->jd_blocks);
777         sdp->sd_log_blks_reserved = reserved;
778
779         gfs2_log_unlock(sdp);
780 }
781
782 static void buf_lo_incore_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
783 {
784         struct list_head *head = &tr->tr_list_buf;
785         struct gfs2_bufdata *bd;
786
787         gfs2_log_lock(sdp);
788         while (!list_empty(head)) {
789                 bd = list_entry(head->next, struct gfs2_bufdata, bd_list_tr);
790                 list_del_init(&bd->bd_list_tr);
791                 tr->tr_num_buf--;
792         }
793         gfs2_log_unlock(sdp);
794         gfs2_assert_warn(sdp, !tr->tr_num_buf);
795 }
796
797 /**
798  * gfs2_log_commit - Commit a transaction to the log
799  * @sdp: the filesystem
800  * @tr: the transaction
801  *
802  * We wake up gfs2_logd if the number of pinned blocks exceed thresh1
803  * or the total number of used blocks (pinned blocks plus AIL blocks)
804  * is greater than thresh2.
805  *
806  * At mount time thresh1 is 1/3rd of journal size, thresh2 is 2/3rd of
807  * journal size.
808  *
809  * Returns: errno
810  */
811
812 void gfs2_log_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
813 {
814         log_refund(sdp, tr);
815         buf_lo_incore_commit(sdp, tr);
816
817         up_read(&sdp->sd_log_flush_lock);
818
819         if (atomic_read(&sdp->sd_log_pinned) > atomic_read(&sdp->sd_log_thresh1) ||
820             ((sdp->sd_jdesc->jd_blocks - atomic_read(&sdp->sd_log_blks_free)) >
821             atomic_read(&sdp->sd_log_thresh2)))
822                 wake_up(&sdp->sd_logd_waitq);
823 }
824
825 /**
826  * gfs2_log_shutdown - write a shutdown header into a journal
827  * @sdp: the filesystem
828  *
829  */
830
831 void gfs2_log_shutdown(struct gfs2_sbd *sdp)
832 {
833         down_write(&sdp->sd_log_flush_lock);
834
835         gfs2_assert_withdraw(sdp, !sdp->sd_log_blks_reserved);
836         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_buf);
837         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
838         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_rg);
839         gfs2_assert_withdraw(sdp, !sdp->sd_log_num_databuf);
840         gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail1_list));
841
842         sdp->sd_log_flush_head = sdp->sd_log_head;
843         sdp->sd_log_flush_wrapped = 0;
844
845         log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT,
846                          (sdp->sd_log_tail == current_tail(sdp)) ? 0 : PULL);
847
848         gfs2_assert_warn(sdp, atomic_read(&sdp->sd_log_blks_free) == sdp->sd_jdesc->jd_blocks);
849         gfs2_assert_warn(sdp, sdp->sd_log_head == sdp->sd_log_tail);
850         gfs2_assert_warn(sdp, list_empty(&sdp->sd_ail2_list));
851
852         sdp->sd_log_head = sdp->sd_log_flush_head;
853         sdp->sd_log_tail = sdp->sd_log_head;
854
855         up_write(&sdp->sd_log_flush_lock);
856 }
857
858
859 /**
860  * gfs2_meta_syncfs - sync all the buffers in a filesystem
861  * @sdp: the filesystem
862  *
863  */
864
865 void gfs2_meta_syncfs(struct gfs2_sbd *sdp)
866 {
867         gfs2_log_flush(sdp, NULL);
868         for (;;) {
869                 gfs2_ail1_start(sdp);
870                 if (gfs2_ail1_empty(sdp, DIO_ALL))
871                         break;
872                 msleep(10);
873         }
874 }
875
876 static inline int gfs2_jrnl_flush_reqd(struct gfs2_sbd *sdp)
877 {
878         return (atomic_read(&sdp->sd_log_pinned) >= atomic_read(&sdp->sd_log_thresh1));
879 }
880
881 static inline int gfs2_ail_flush_reqd(struct gfs2_sbd *sdp)
882 {
883         unsigned int used_blocks = sdp->sd_jdesc->jd_blocks - atomic_read(&sdp->sd_log_blks_free);
884         return used_blocks >= atomic_read(&sdp->sd_log_thresh2);
885 }
886
887 /**
888  * gfs2_logd - Update log tail as Active Items get flushed to in-place blocks
889  * @sdp: Pointer to GFS2 superblock
890  *
891  * Also, periodically check to make sure that we're using the most recent
892  * journal index.
893  */
894
895 int gfs2_logd(void *data)
896 {
897         struct gfs2_sbd *sdp = data;
898         unsigned long t = 1;
899         DEFINE_WAIT(wait);
900         unsigned preflush;
901
902         while (!kthread_should_stop()) {
903
904                 preflush = atomic_read(&sdp->sd_log_pinned);
905                 if (gfs2_jrnl_flush_reqd(sdp) || t == 0) {
906                         gfs2_ail1_empty(sdp, DIO_ALL);
907                         gfs2_log_flush(sdp, NULL);
908                         gfs2_ail1_empty(sdp, DIO_ALL);
909                 }
910
911                 if (gfs2_ail_flush_reqd(sdp)) {
912                         gfs2_ail1_start(sdp);
913                         io_schedule();
914                         gfs2_ail1_empty(sdp, 0);
915                         gfs2_log_flush(sdp, NULL);
916                         gfs2_ail1_empty(sdp, DIO_ALL);
917                 }
918
919                 wake_up(&sdp->sd_log_waitq);
920                 t = gfs2_tune_get(sdp, gt_logd_secs) * HZ;
921                 if (freezing(current))
922                         refrigerator();
923
924                 do {
925                         prepare_to_wait(&sdp->sd_logd_waitq, &wait,
926                                         TASK_INTERRUPTIBLE);
927                         if (!gfs2_ail_flush_reqd(sdp) &&
928                             !gfs2_jrnl_flush_reqd(sdp) &&
929                             !kthread_should_stop())
930                                 t = schedule_timeout(t);
931                 } while(t && !gfs2_ail_flush_reqd(sdp) &&
932                         !gfs2_jrnl_flush_reqd(sdp) &&
933                         !kthread_should_stop());
934                 finish_wait(&sdp->sd_logd_waitq, &wait);
935         }
936
937         return 0;
938 }
939