[GFS2] Macros removal in gfs2.h
[linux-2.6.git] / fs / gfs2 / meta_io.c
1 /*
2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
3  * Copyright (C) 2004-2005 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 v.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/mm.h>
16 #include <linux/pagemap.h>
17 #include <linux/writeback.h>
18 #include <linux/swap.h>
19 #include <linux/delay.h>
20 #include <linux/gfs2_ondisk.h>
21 #include <asm/semaphore.h>
22
23 #include "gfs2.h"
24 #include "lm_interface.h"
25 #include "incore.h"
26 #include "glock.h"
27 #include "glops.h"
28 #include "inode.h"
29 #include "log.h"
30 #include "lops.h"
31 #include "meta_io.h"
32 #include "rgrp.h"
33 #include "trans.h"
34 #include "util.h"
35
36 #define buffer_busy(bh) \
37 ((bh)->b_state & ((1ul << BH_Dirty) | (1ul << BH_Lock) | (1ul << BH_Pinned)))
38 #define buffer_in_io(bh) \
39 ((bh)->b_state & ((1ul << BH_Dirty) | (1ul << BH_Lock)))
40
41 static int aspace_get_block(struct inode *inode, sector_t lblock,
42                             struct buffer_head *bh_result, int create)
43 {
44         gfs2_assert_warn(inode->i_sb->s_fs_info, 0);
45         return -EOPNOTSUPP;
46 }
47
48 static int gfs2_aspace_writepage(struct page *page,
49                                  struct writeback_control *wbc)
50 {
51         return block_write_full_page(page, aspace_get_block, wbc);
52 }
53
54 /**
55  * stuck_releasepage - We're stuck in gfs2_releasepage().  Print stuff out.
56  * @bh: the buffer we're stuck on
57  *
58  */
59
60 static void stuck_releasepage(struct buffer_head *bh)
61 {
62         struct gfs2_sbd *sdp = bh->b_page->mapping->host->i_sb->s_fs_info;
63         struct gfs2_bufdata *bd = bh->b_private;
64         struct gfs2_glock *gl;
65
66         fs_warn(sdp, "stuck in gfs2_releasepage()\n");
67         fs_warn(sdp, "blkno = %llu, bh->b_count = %d\n",
68                 (uint64_t)bh->b_blocknr, atomic_read(&bh->b_count));
69         fs_warn(sdp, "pinned = %u\n", buffer_pinned(bh));
70         fs_warn(sdp, "bh->b_private = %s\n", (bd) ? "!NULL" : "NULL");
71
72         if (!bd)
73                 return;
74
75         gl = bd->bd_gl;
76
77         fs_warn(sdp, "gl = (%u, %llu)\n", 
78                 gl->gl_name.ln_type, gl->gl_name.ln_number);
79
80         fs_warn(sdp, "bd_list_tr = %s, bd_le.le_list = %s\n",
81                 (list_empty(&bd->bd_list_tr)) ? "no" : "yes",
82                 (list_empty(&bd->bd_le.le_list)) ? "no" : "yes");
83
84         if (gl->gl_ops == &gfs2_inode_glops) {
85                 struct gfs2_inode *ip = gl->gl_object;
86                 unsigned int x;
87
88                 if (!ip)
89                         return;
90
91                 fs_warn(sdp, "ip = %llu %llu\n",
92                         ip->i_num.no_formal_ino, ip->i_num.no_addr);
93                 fs_warn(sdp, "ip->i_count = %d, ip->i_vnode = %s\n",
94                         atomic_read(&ip->i_count),
95                         (ip->i_vnode) ? "!NULL" : "NULL");
96
97                 for (x = 0; x < GFS2_MAX_META_HEIGHT; x++)
98                         fs_warn(sdp, "ip->i_cache[%u] = %s\n",
99                                 x, (ip->i_cache[x]) ? "!NULL" : "NULL");
100         }
101 }
102
103 /**
104  * gfs2_aspace_releasepage - free the metadata associated with a page
105  * @page: the page that's being released
106  * @gfp_mask: passed from Linux VFS, ignored by us
107  *
108  * Call try_to_free_buffers() if the buffers in this page can be
109  * released.
110  *
111  * Returns: 0
112  */
113
114 static int gfs2_aspace_releasepage(struct page *page, gfp_t gfp_mask)
115 {
116         struct inode *aspace = page->mapping->host;
117         struct gfs2_sbd *sdp = aspace->i_sb->s_fs_info;
118         struct buffer_head *bh, *head;
119         struct gfs2_bufdata *bd;
120         unsigned long t;
121
122         if (!page_has_buffers(page))
123                 goto out;
124
125         head = bh = page_buffers(page);
126         do {
127                 t = jiffies;
128
129                 while (atomic_read(&bh->b_count)) {
130                         if (atomic_read(&aspace->i_writecount)) {
131                                 if (time_after_eq(jiffies, t +
132                                     gfs2_tune_get(sdp, gt_stall_secs) * HZ)) {
133                                         stuck_releasepage(bh);
134                                         t = jiffies;
135                                 }
136
137                                 yield();
138                                 continue;
139                         }
140
141                         return 0;
142                 }
143
144                 gfs2_assert_warn(sdp, !buffer_pinned(bh));
145
146                 bd = bh->b_private;
147                 if (bd) {
148                         gfs2_assert_warn(sdp, bd->bd_bh == bh);
149                         gfs2_assert_warn(sdp, list_empty(&bd->bd_list_tr));
150                         gfs2_assert_warn(sdp, list_empty(&bd->bd_le.le_list));
151                         gfs2_assert_warn(sdp, !bd->bd_ail);
152                         kmem_cache_free(gfs2_bufdata_cachep, bd);
153                         bh->b_private = NULL;
154                 }
155
156                 bh = bh->b_this_page;
157         }
158         while (bh != head);
159
160  out:
161         return try_to_free_buffers(page);
162 }
163
164 static struct address_space_operations aspace_aops = {
165         .writepage = gfs2_aspace_writepage,
166         .releasepage = gfs2_aspace_releasepage,
167 };
168
169 /**
170  * gfs2_aspace_get - Create and initialize a struct inode structure
171  * @sdp: the filesystem the aspace is in
172  *
173  * Right now a struct inode is just a struct inode.  Maybe Linux
174  * will supply a more lightweight address space construct (that works)
175  * in the future.
176  *
177  * Make sure pages/buffers in this aspace aren't in high memory.
178  *
179  * Returns: the aspace
180  */
181
182 struct inode *gfs2_aspace_get(struct gfs2_sbd *sdp)
183 {
184         struct inode *aspace;
185
186         aspace = new_inode(sdp->sd_vfs);
187         if (aspace) {
188                 mapping_set_gfp_mask(aspace->i_mapping, GFP_KERNEL);
189                 aspace->i_mapping->a_ops = &aspace_aops;
190                 aspace->i_size = ~0ULL;
191                 aspace->u.generic_ip = NULL;
192                 insert_inode_hash(aspace);
193         }
194
195         return aspace;
196 }
197
198 void gfs2_aspace_put(struct inode *aspace)
199 {
200         remove_inode_hash(aspace);
201         iput(aspace);
202 }
203
204 /**
205  * gfs2_ail1_start_one - Start I/O on a part of the AIL
206  * @sdp: the filesystem
207  * @tr: the part of the AIL
208  *
209  */
210
211 void gfs2_ail1_start_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
212 {
213         struct gfs2_bufdata *bd, *s;
214         struct buffer_head *bh;
215         int retry;
216
217         do {
218                 retry = 0;
219
220                 list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list,
221                                                  bd_ail_st_list) {
222                         bh = bd->bd_bh;
223
224                         gfs2_assert(sdp, bd->bd_ail == ai);
225
226                         if (!buffer_busy(bh)) {
227                                 if (!buffer_uptodate(bh))
228                                         gfs2_io_error_bh(sdp, bh);
229                                 list_move(&bd->bd_ail_st_list,
230                                           &ai->ai_ail2_list);
231                                 continue;
232                         }
233
234                         if (!buffer_dirty(bh))
235                                 continue;
236
237                         list_move(&bd->bd_ail_st_list, &ai->ai_ail1_list);
238
239                         gfs2_log_unlock(sdp);
240                         wait_on_buffer(bh);
241                         ll_rw_block(WRITE, 1, &bh);
242                         gfs2_log_lock(sdp);
243
244                         retry = 1;
245                         break;
246                 }
247         } while (retry);
248 }
249
250 /**
251  * gfs2_ail1_empty_one - Check whether or not a trans in the AIL has been synced
252  * @sdp: the filesystem
253  * @ai: the AIL entry
254  *
255  */
256
257 int gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai, int flags)
258 {
259         struct gfs2_bufdata *bd, *s;
260         struct buffer_head *bh;
261
262         list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list,
263                                          bd_ail_st_list) {
264                 bh = bd->bd_bh;
265
266                 gfs2_assert(sdp, bd->bd_ail == ai);
267
268                 if (buffer_busy(bh)) {
269                         if (flags & DIO_ALL)
270                                 continue;
271                         else
272                                 break;
273                 }
274
275                 if (!buffer_uptodate(bh))
276                         gfs2_io_error_bh(sdp, bh);
277
278                 list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list);
279         }
280
281         return list_empty(&ai->ai_ail1_list);
282 }
283
284 /**
285  * gfs2_ail2_empty_one - Check whether or not a trans in the AIL has been synced
286  * @sdp: the filesystem
287  * @ai: the AIL entry
288  *
289  */
290
291 void gfs2_ail2_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
292 {
293         struct list_head *head = &ai->ai_ail2_list;
294         struct gfs2_bufdata *bd;
295
296         while (!list_empty(head)) {
297                 bd = list_entry(head->prev, struct gfs2_bufdata,
298                                 bd_ail_st_list);
299                 gfs2_assert(sdp, bd->bd_ail == ai);
300                 bd->bd_ail = NULL;
301                 list_del(&bd->bd_ail_st_list);
302                 list_del(&bd->bd_ail_gl_list);
303                 atomic_dec(&bd->bd_gl->gl_ail_count);
304                 brelse(bd->bd_bh);
305         }
306 }
307
308 /**
309  * ail_empty_gl - remove all buffers for a given lock from the AIL
310  * @gl: the glock
311  *
312  * None of the buffers should be dirty, locked, or pinned.
313  */
314
315 void gfs2_ail_empty_gl(struct gfs2_glock *gl)
316 {
317         struct gfs2_sbd *sdp = gl->gl_sbd;
318         unsigned int blocks;
319         struct list_head *head = &gl->gl_ail_list;
320         struct gfs2_bufdata *bd;
321         struct buffer_head *bh;
322         uint64_t blkno;
323         int error;
324
325         blocks = atomic_read(&gl->gl_ail_count);
326         if (!blocks)
327                 return;
328
329         error = gfs2_trans_begin(sdp, 0, blocks);
330         if (gfs2_assert_withdraw(sdp, !error))
331                 return;
332
333         gfs2_log_lock(sdp);
334         while (!list_empty(head)) {
335                 bd = list_entry(head->next, struct gfs2_bufdata,
336                                 bd_ail_gl_list);
337                 bh = bd->bd_bh;
338                 blkno = bh->b_blocknr;
339                 gfs2_assert_withdraw(sdp, !buffer_busy(bh));
340
341                 bd->bd_ail = NULL;
342                 list_del(&bd->bd_ail_st_list);
343                 list_del(&bd->bd_ail_gl_list);
344                 atomic_dec(&gl->gl_ail_count);
345                 brelse(bh);
346                 gfs2_log_unlock(sdp);
347
348                 gfs2_trans_add_revoke(sdp, blkno);
349
350                 gfs2_log_lock(sdp);
351         }
352         gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
353         gfs2_log_unlock(sdp);
354
355         gfs2_trans_end(sdp);
356         gfs2_log_flush(sdp);
357 }
358
359 /**
360  * gfs2_meta_inval - Invalidate all buffers associated with a glock
361  * @gl: the glock
362  *
363  */
364
365 void gfs2_meta_inval(struct gfs2_glock *gl)
366 {
367         struct gfs2_sbd *sdp = gl->gl_sbd;
368         struct inode *aspace = gl->gl_aspace;
369         struct address_space *mapping = gl->gl_aspace->i_mapping;
370
371         gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
372
373         atomic_inc(&aspace->i_writecount);
374         truncate_inode_pages(mapping, 0);
375         atomic_dec(&aspace->i_writecount);
376
377         gfs2_assert_withdraw(sdp, !mapping->nrpages);
378 }
379
380 /**
381  * gfs2_meta_sync - Sync all buffers associated with a glock
382  * @gl: The glock
383  * @flags: DIO_START | DIO_WAIT
384  *
385  */
386
387 void gfs2_meta_sync(struct gfs2_glock *gl, int flags)
388 {
389         struct address_space *mapping = gl->gl_aspace->i_mapping;
390         int error = 0;
391
392         if (flags & DIO_START)
393                 filemap_fdatawrite(mapping);
394         if (!error && (flags & DIO_WAIT))
395                 error = filemap_fdatawait(mapping);
396
397         if (error)
398                 gfs2_io_error(gl->gl_sbd);
399 }
400
401 /**
402  * getbuf - Get a buffer with a given address space
403  * @sdp: the filesystem
404  * @aspace: the address space
405  * @blkno: the block number (filesystem scope)
406  * @create: 1 if the buffer should be created
407  *
408  * Returns: the buffer
409  */
410
411 static struct buffer_head *getbuf(struct gfs2_sbd *sdp, struct inode *aspace,
412                                   uint64_t blkno, int create)
413 {
414         struct page *page;
415         struct buffer_head *bh;
416         unsigned int shift;
417         unsigned long index;
418         unsigned int bufnum;
419
420         shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;
421         index = blkno >> shift;             /* convert block to page */
422         bufnum = blkno - (index << shift);  /* block buf index within page */
423
424         if (create) {
425                 for (;;) {
426                         page = grab_cache_page(aspace->i_mapping, index);
427                         if (page)
428                                 break;
429                         yield();
430                 }
431         } else {
432                 page = find_lock_page(aspace->i_mapping, index);
433                 if (!page)
434                         return NULL;
435         }
436
437         if (!page_has_buffers(page))
438                 create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);
439
440         /* Locate header for our buffer within our page */
441         for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
442                 /* Do nothing */;
443         get_bh(bh);
444
445         if (!buffer_mapped(bh))
446                 map_bh(bh, sdp->sd_vfs, blkno);
447
448         unlock_page(page);
449         mark_page_accessed(page);
450         page_cache_release(page);
451
452         return bh;
453 }
454
455 static void meta_prep_new(struct buffer_head *bh)
456 {
457         struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
458
459         lock_buffer(bh);
460         clear_buffer_dirty(bh);
461         set_buffer_uptodate(bh);
462         unlock_buffer(bh);
463
464         mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
465 }
466
467 /**
468  * gfs2_meta_new - Get a block
469  * @gl: The glock associated with this block
470  * @blkno: The block number
471  *
472  * Returns: The buffer
473  */
474
475 struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, uint64_t blkno)
476 {
477         struct buffer_head *bh;
478         bh = getbuf(gl->gl_sbd, gl->gl_aspace, blkno, CREATE);
479         meta_prep_new(bh);
480         return bh;
481 }
482
483 /**
484  * gfs2_meta_read - Read a block from disk
485  * @gl: The glock covering the block
486  * @blkno: The block number
487  * @flags: flags to gfs2_dreread()
488  * @bhp: the place where the buffer is returned (NULL on failure)
489  *
490  * Returns: errno
491  */
492
493 int gfs2_meta_read(struct gfs2_glock *gl, uint64_t blkno, int flags,
494                    struct buffer_head **bhp)
495 {
496         int error;
497
498         *bhp = getbuf(gl->gl_sbd, gl->gl_aspace, blkno, CREATE);
499         error = gfs2_meta_reread(gl->gl_sbd, *bhp, flags);
500         if (error)
501                 brelse(*bhp);
502
503         return error;
504 }
505
506 /**
507  * gfs2_meta_reread - Reread a block from disk
508  * @sdp: the filesystem
509  * @bh: The block to read
510  * @flags: Flags that control the read
511  *
512  * Returns: errno
513  */
514
515 int gfs2_meta_reread(struct gfs2_sbd *sdp, struct buffer_head *bh, int flags)
516 {
517         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
518                 return -EIO;
519
520         if (flags & DIO_FORCE)
521                 clear_buffer_uptodate(bh);
522
523         if ((flags & DIO_START) && !buffer_uptodate(bh))
524                 ll_rw_block(READ, 1, &bh);
525
526         if (flags & DIO_WAIT) {
527                 wait_on_buffer(bh);
528
529                 if (!buffer_uptodate(bh)) {
530                         struct gfs2_trans *tr = current->journal_info;
531                         if (tr && tr->tr_touched)
532                                 gfs2_io_error_bh(sdp, bh);
533                         return -EIO;
534                 }
535                 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
536                         return -EIO;
537         }
538
539         return 0;
540 }
541
542 /**
543  * gfs2_attach_bufdata - attach a struct gfs2_bufdata structure to a buffer
544  * @gl: the glock the buffer belongs to
545  * @bh: The buffer to be attached to
546  * @meta: Flag to indicate whether its metadata or not
547  */
548
549 void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
550                          int meta)
551 {
552         struct gfs2_bufdata *bd;
553
554         if (meta)
555                 lock_page(bh->b_page);
556
557         if (bh->b_private) {
558                 if (meta)
559                         unlock_page(bh->b_page);
560                 return;
561         }
562
563         bd = kmem_cache_alloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL),
564         memset(bd, 0, sizeof(struct gfs2_bufdata));
565
566         bd->bd_bh = bh;
567         bd->bd_gl = gl;
568
569         INIT_LIST_HEAD(&bd->bd_list_tr);
570         if (meta) {
571                 lops_init_le(&bd->bd_le, &gfs2_buf_lops);
572         } else {
573                 lops_init_le(&bd->bd_le, &gfs2_databuf_lops);
574                 get_bh(bh);
575         }
576         bh->b_private = bd;
577
578         if (meta)
579                 unlock_page(bh->b_page);
580 }
581
582 /**
583  * gfs2_pin - Pin a buffer in memory
584  * @sdp: the filesystem the buffer belongs to
585  * @bh: The buffer to be pinned
586  *
587  */
588
589 void gfs2_pin(struct gfs2_sbd *sdp, struct buffer_head *bh)
590 {
591         struct gfs2_bufdata *bd = bh->b_private;
592
593         gfs2_assert_withdraw(sdp, test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags));
594
595         if (test_set_buffer_pinned(bh))
596                 gfs2_assert_withdraw(sdp, 0);
597
598         wait_on_buffer(bh);
599
600         /* If this buffer is in the AIL and it has already been written
601            to in-place disk block, remove it from the AIL. */
602
603         gfs2_log_lock(sdp);
604         if (bd->bd_ail && !buffer_in_io(bh))
605                 list_move(&bd->bd_ail_st_list, &bd->bd_ail->ai_ail2_list);
606         gfs2_log_unlock(sdp);
607
608         clear_buffer_dirty(bh);
609         wait_on_buffer(bh);
610
611         if (!buffer_uptodate(bh))
612                 gfs2_io_error_bh(sdp, bh);
613
614         get_bh(bh);
615 }
616
617 /**
618  * gfs2_unpin - Unpin a buffer
619  * @sdp: the filesystem the buffer belongs to
620  * @bh: The buffer to unpin
621  * @ai:
622  *
623  */
624
625 void gfs2_unpin(struct gfs2_sbd *sdp, struct buffer_head *bh,
626                 struct gfs2_ail *ai)
627 {
628         struct gfs2_bufdata *bd = bh->b_private;
629
630         gfs2_assert_withdraw(sdp, buffer_uptodate(bh));
631
632         if (!buffer_pinned(bh))
633                 gfs2_assert_withdraw(sdp, 0);
634
635         mark_buffer_dirty(bh);
636         clear_buffer_pinned(bh);
637
638         gfs2_log_lock(sdp);
639         if (bd->bd_ail) {
640                 list_del(&bd->bd_ail_st_list);
641                 brelse(bh);
642         } else {
643                 struct gfs2_glock *gl = bd->bd_gl;
644                 list_add(&bd->bd_ail_gl_list, &gl->gl_ail_list);
645                 atomic_inc(&gl->gl_ail_count);
646         }
647         bd->bd_ail = ai;
648         list_add(&bd->bd_ail_st_list, &ai->ai_ail1_list);
649         gfs2_log_unlock(sdp);
650 }
651
652 /**
653  * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
654  * @ip: the inode who owns the buffers
655  * @bstart: the first buffer in the run
656  * @blen: the number of buffers in the run
657  *
658  */
659
660 void gfs2_meta_wipe(struct gfs2_inode *ip, uint64_t bstart, uint32_t blen)
661 {
662         struct gfs2_sbd *sdp = ip->i_sbd;
663         struct inode *aspace = ip->i_gl->gl_aspace;
664         struct buffer_head *bh;
665
666         while (blen) {
667                 bh = getbuf(sdp, aspace, bstart, NO_CREATE);
668                 if (bh) {
669                         struct gfs2_bufdata *bd = bh->b_private;
670
671                         if (test_clear_buffer_pinned(bh)) {
672                                 struct gfs2_trans *tr = current->journal_info;
673                                 gfs2_log_lock(sdp);
674                                 list_del_init(&bd->bd_le.le_list);
675                                 gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
676                                 sdp->sd_log_num_buf--;
677                                 gfs2_log_unlock(sdp);
678                                 tr->tr_num_buf_rm++;
679                                 brelse(bh);
680                         }
681                         if (bd) {
682                                 gfs2_log_lock(sdp);
683                                 if (bd->bd_ail) {
684                                         uint64_t blkno = bh->b_blocknr;
685                                         bd->bd_ail = NULL;
686                                         list_del(&bd->bd_ail_st_list);
687                                         list_del(&bd->bd_ail_gl_list);
688                                         atomic_dec(&bd->bd_gl->gl_ail_count);
689                                         brelse(bh);
690                                         gfs2_log_unlock(sdp);
691                                         gfs2_trans_add_revoke(sdp, blkno);
692                                 } else
693                                         gfs2_log_unlock(sdp);
694                         }
695
696                         lock_buffer(bh);
697                         clear_buffer_dirty(bh);
698                         clear_buffer_uptodate(bh);
699                         unlock_buffer(bh);
700
701                         brelse(bh);
702                 }
703
704                 bstart++;
705                 blen--;
706         }
707 }
708
709 /**
710  * gfs2_meta_cache_flush - get rid of any references on buffers for this inode
711  * @ip: The GFS2 inode
712  *
713  * This releases buffers that are in the most-recently-used array of
714  * blocks used for indirect block addressing for this inode.
715  */
716
717 void gfs2_meta_cache_flush(struct gfs2_inode *ip)
718 {
719         struct buffer_head **bh_slot;
720         unsigned int x;
721
722         spin_lock(&ip->i_spin);
723
724         for (x = 0; x < GFS2_MAX_META_HEIGHT; x++) {
725                 bh_slot = &ip->i_cache[x];
726                 if (!*bh_slot)
727                         break;
728                 brelse(*bh_slot);
729                 *bh_slot = NULL;
730         }
731
732         spin_unlock(&ip->i_spin);
733 }
734
735 /**
736  * gfs2_meta_indirect_buffer - Get a metadata buffer
737  * @ip: The GFS2 inode
738  * @height: The level of this buf in the metadata (indir addr) tree (if any)
739  * @num: The block number (device relative) of the buffer
740  * @new: Non-zero if we may create a new buffer
741  * @bhp: the buffer is returned here
742  *
743  * Try to use the gfs2_inode's MRU metadata tree cache.
744  *
745  * Returns: errno
746  */
747
748 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, uint64_t num,
749                               int new, struct buffer_head **bhp)
750 {
751         struct buffer_head *bh, **bh_slot = ip->i_cache + height;
752         int error;
753
754         spin_lock(&ip->i_spin);
755         bh = *bh_slot;
756         if (bh) {
757                 if (bh->b_blocknr == num)
758                         get_bh(bh);
759                 else
760                         bh = NULL;
761         }
762         spin_unlock(&ip->i_spin);
763
764         if (bh) {
765                 if (new)
766                         meta_prep_new(bh);
767                 else {
768                         error = gfs2_meta_reread(ip->i_sbd, bh,
769                                                  DIO_START | DIO_WAIT);
770                         if (error) {
771                                 brelse(bh);
772                                 return error;
773                         }
774                 }
775         } else {
776                 if (new)
777                         bh = gfs2_meta_new(ip->i_gl, num);
778                 else {
779                         error = gfs2_meta_read(ip->i_gl, num,
780                                                DIO_START | DIO_WAIT, &bh);
781                         if (error)
782                                 return error;
783                 }
784
785                 spin_lock(&ip->i_spin);
786                 if (*bh_slot != bh) {
787                         brelse(*bh_slot);
788                         *bh_slot = bh;
789                         get_bh(bh);
790                 }
791                 spin_unlock(&ip->i_spin);
792         }
793
794         if (new) {
795                 if (gfs2_assert_warn(ip->i_sbd, height)) {
796                         brelse(bh);
797                         return -EIO;
798                 }
799                 gfs2_trans_add_bh(ip->i_gl, bh, 1);
800                 gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
801                 gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
802
803         } else if (gfs2_metatype_check(ip->i_sbd, bh,
804                              (height) ? GFS2_METATYPE_IN : GFS2_METATYPE_DI)) {
805                 brelse(bh);
806                 return -EIO;
807         }
808
809         *bhp = bh;
810
811         return 0;
812 }
813
814 /**
815  * gfs2_meta_ra - start readahead on an extent of a file
816  * @gl: the glock the blocks belong to
817  * @dblock: the starting disk block
818  * @extlen: the number of blocks in the extent
819  *
820  */
821
822 void gfs2_meta_ra(struct gfs2_glock *gl, uint64_t dblock, uint32_t extlen)
823 {
824         struct gfs2_sbd *sdp = gl->gl_sbd;
825         struct inode *aspace = gl->gl_aspace;
826         struct buffer_head *first_bh, *bh;
827         uint32_t max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
828                           sdp->sd_sb.sb_bsize_shift;
829         int error;
830
831         if (!extlen || !max_ra)
832                 return;
833         if (extlen > max_ra)
834                 extlen = max_ra;
835
836         first_bh = getbuf(sdp, aspace, dblock, CREATE);
837
838         if (buffer_uptodate(first_bh))
839                 goto out;
840         if (!buffer_locked(first_bh)) {
841                 error = gfs2_meta_reread(sdp, first_bh, DIO_START);
842                 if (error)
843                         goto out;
844         }
845
846         dblock++;
847         extlen--;
848
849         while (extlen) {
850                 bh = getbuf(sdp, aspace, dblock, CREATE);
851
852                 if (!buffer_uptodate(bh) && !buffer_locked(bh)) {
853                         error = gfs2_meta_reread(sdp, bh, DIO_START);
854                         brelse(bh);
855                         if (error)
856                                 goto out;
857                 } else
858                         brelse(bh);
859
860                 dblock++;
861                 extlen--;
862
863                 if (buffer_uptodate(first_bh))
864                         break;
865         }
866
867  out:
868         brelse(first_bh);
869 }
870
871 /**
872  * gfs2_meta_syncfs - sync all the buffers in a filesystem
873  * @sdp: the filesystem
874  *
875  */
876
877 void gfs2_meta_syncfs(struct gfs2_sbd *sdp)
878 {
879         gfs2_log_flush(sdp);
880         for (;;) {
881                 gfs2_ail1_start(sdp, DIO_ALL);
882                 if (gfs2_ail1_empty(sdp, DIO_ALL))
883                         break;
884                 msleep(100);
885         }
886 }
887