[GFS2] Fix deadlock in memory allocation
[linux-2.6.git] / fs / gfs2 / meta_io.c
1 /*
2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
3  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
4  *
5  * This copyrighted material is made available to anyone wishing to use,
6  * modify, copy, or redistribute it subject to the terms and conditions
7  * of the GNU General Public License 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
22 #include "gfs2.h"
23 #include "lm_interface.h"
24 #include "incore.h"
25 #include "glock.h"
26 #include "glops.h"
27 #include "inode.h"
28 #include "log.h"
29 #include "lops.h"
30 #include "meta_io.h"
31 #include "rgrp.h"
32 #include "trans.h"
33 #include "util.h"
34 #include "ops_address.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 static const struct address_space_operations aspace_aops = {
55         .writepage = gfs2_aspace_writepage,
56         .releasepage = gfs2_releasepage,
57 };
58
59 /**
60  * gfs2_aspace_get - Create and initialize a struct inode structure
61  * @sdp: the filesystem the aspace is in
62  *
63  * Right now a struct inode is just a struct inode.  Maybe Linux
64  * will supply a more lightweight address space construct (that works)
65  * in the future.
66  *
67  * Make sure pages/buffers in this aspace aren't in high memory.
68  *
69  * Returns: the aspace
70  */
71
72 struct inode *gfs2_aspace_get(struct gfs2_sbd *sdp)
73 {
74         struct inode *aspace;
75
76         aspace = new_inode(sdp->sd_vfs);
77         if (aspace) {
78                 mapping_set_gfp_mask(aspace->i_mapping, GFP_NOFS);
79                 aspace->i_mapping->a_ops = &aspace_aops;
80                 aspace->i_size = ~0ULL;
81                 aspace->u.generic_ip = NULL;
82                 insert_inode_hash(aspace);
83         }
84         return aspace;
85 }
86
87 void gfs2_aspace_put(struct inode *aspace)
88 {
89         remove_inode_hash(aspace);
90         iput(aspace);
91 }
92
93 /**
94  * gfs2_ail1_start_one - Start I/O on a part of the AIL
95  * @sdp: the filesystem
96  * @tr: the part of the AIL
97  *
98  */
99
100 void gfs2_ail1_start_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
101 {
102         struct gfs2_bufdata *bd, *s;
103         struct buffer_head *bh;
104         int retry;
105
106         BUG_ON(!spin_is_locked(&sdp->sd_log_lock));
107
108         do {
109                 retry = 0;
110
111                 list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list,
112                                                  bd_ail_st_list) {
113                         bh = bd->bd_bh;
114
115                         gfs2_assert(sdp, bd->bd_ail == ai);
116
117                         if (!buffer_busy(bh)) {
118                                 if (!buffer_uptodate(bh)) {
119                                         gfs2_log_unlock(sdp);
120                                         gfs2_io_error_bh(sdp, bh);
121                                         gfs2_log_lock(sdp);
122                                 }
123                                 list_move(&bd->bd_ail_st_list,
124                                           &ai->ai_ail2_list);
125                                 continue;
126                         }
127
128                         if (!buffer_dirty(bh))
129                                 continue;
130
131                         list_move(&bd->bd_ail_st_list, &ai->ai_ail1_list);
132
133                         gfs2_log_unlock(sdp);
134                         wait_on_buffer(bh);
135                         ll_rw_block(WRITE, 1, &bh);
136                         gfs2_log_lock(sdp);
137
138                         retry = 1;
139                         break;
140                 }
141         } while (retry);
142 }
143
144 /**
145  * gfs2_ail1_empty_one - Check whether or not a trans in the AIL has been synced
146  * @sdp: the filesystem
147  * @ai: the AIL entry
148  *
149  */
150
151 int gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai, int flags)
152 {
153         struct gfs2_bufdata *bd, *s;
154         struct buffer_head *bh;
155
156         list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list,
157                                          bd_ail_st_list) {
158                 bh = bd->bd_bh;
159
160                 gfs2_assert(sdp, bd->bd_ail == ai);
161
162                 if (buffer_busy(bh)) {
163                         if (flags & DIO_ALL)
164                                 continue;
165                         else
166                                 break;
167                 }
168
169                 if (!buffer_uptodate(bh))
170                         gfs2_io_error_bh(sdp, bh);
171
172                 list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list);
173         }
174
175         return list_empty(&ai->ai_ail1_list);
176 }
177
178 /**
179  * gfs2_ail2_empty_one - Check whether or not a trans in the AIL has been synced
180  * @sdp: the filesystem
181  * @ai: the AIL entry
182  *
183  */
184
185 void gfs2_ail2_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
186 {
187         struct list_head *head = &ai->ai_ail2_list;
188         struct gfs2_bufdata *bd;
189
190         while (!list_empty(head)) {
191                 bd = list_entry(head->prev, struct gfs2_bufdata,
192                                 bd_ail_st_list);
193                 gfs2_assert(sdp, bd->bd_ail == ai);
194                 bd->bd_ail = NULL;
195                 list_del(&bd->bd_ail_st_list);
196                 list_del(&bd->bd_ail_gl_list);
197                 atomic_dec(&bd->bd_gl->gl_ail_count);
198                 brelse(bd->bd_bh);
199         }
200 }
201
202 /**
203  * ail_empty_gl - remove all buffers for a given lock from the AIL
204  * @gl: the glock
205  *
206  * None of the buffers should be dirty, locked, or pinned.
207  */
208
209 void gfs2_ail_empty_gl(struct gfs2_glock *gl)
210 {
211         struct gfs2_sbd *sdp = gl->gl_sbd;
212         unsigned int blocks;
213         struct list_head *head = &gl->gl_ail_list;
214         struct gfs2_bufdata *bd;
215         struct buffer_head *bh;
216         uint64_t blkno;
217         int error;
218
219         blocks = atomic_read(&gl->gl_ail_count);
220         if (!blocks)
221                 return;
222
223         error = gfs2_trans_begin(sdp, 0, blocks);
224         if (gfs2_assert_withdraw(sdp, !error))
225                 return;
226
227         gfs2_log_lock(sdp);
228         while (!list_empty(head)) {
229                 bd = list_entry(head->next, struct gfs2_bufdata,
230                                 bd_ail_gl_list);
231                 bh = bd->bd_bh;
232                 blkno = bh->b_blocknr;
233                 gfs2_assert_withdraw(sdp, !buffer_busy(bh));
234
235                 bd->bd_ail = NULL;
236                 list_del(&bd->bd_ail_st_list);
237                 list_del(&bd->bd_ail_gl_list);
238                 atomic_dec(&gl->gl_ail_count);
239                 brelse(bh);
240                 gfs2_log_unlock(sdp);
241
242                 gfs2_trans_add_revoke(sdp, blkno);
243
244                 gfs2_log_lock(sdp);
245         }
246         gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
247         gfs2_log_unlock(sdp);
248
249         gfs2_trans_end(sdp);
250         gfs2_log_flush(sdp, NULL);
251 }
252
253 /**
254  * gfs2_meta_inval - Invalidate all buffers associated with a glock
255  * @gl: the glock
256  *
257  */
258
259 void gfs2_meta_inval(struct gfs2_glock *gl)
260 {
261         struct gfs2_sbd *sdp = gl->gl_sbd;
262         struct inode *aspace = gl->gl_aspace;
263         struct address_space *mapping = gl->gl_aspace->i_mapping;
264
265         gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
266
267         atomic_inc(&aspace->i_writecount);
268         truncate_inode_pages(mapping, 0);
269         atomic_dec(&aspace->i_writecount);
270
271         gfs2_assert_withdraw(sdp, !mapping->nrpages);
272 }
273
274 /**
275  * gfs2_meta_sync - Sync all buffers associated with a glock
276  * @gl: The glock
277  * @flags: DIO_START | DIO_WAIT
278  *
279  */
280
281 void gfs2_meta_sync(struct gfs2_glock *gl, int flags)
282 {
283         struct address_space *mapping = gl->gl_aspace->i_mapping;
284         int error = 0;
285
286         if (flags & DIO_START)
287                 filemap_fdatawrite(mapping);
288         if (!error && (flags & DIO_WAIT))
289                 error = filemap_fdatawait(mapping);
290
291         if (error)
292                 gfs2_io_error(gl->gl_sbd);
293 }
294
295 /**
296  * getbuf - Get a buffer with a given address space
297  * @sdp: the filesystem
298  * @aspace: the address space
299  * @blkno: the block number (filesystem scope)
300  * @create: 1 if the buffer should be created
301  *
302  * Returns: the buffer
303  */
304
305 static struct buffer_head *getbuf(struct gfs2_sbd *sdp, struct inode *aspace,
306                                   uint64_t blkno, int create)
307 {
308         struct page *page;
309         struct buffer_head *bh;
310         unsigned int shift;
311         unsigned long index;
312         unsigned int bufnum;
313
314         shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;
315         index = blkno >> shift;             /* convert block to page */
316         bufnum = blkno - (index << shift);  /* block buf index within page */
317
318         if (create) {
319                 for (;;) {
320                         page = grab_cache_page(aspace->i_mapping, index);
321                         if (page)
322                                 break;
323                         yield();
324                 }
325         } else {
326                 page = find_lock_page(aspace->i_mapping, index);
327                 if (!page)
328                         return NULL;
329         }
330
331         if (!page_has_buffers(page))
332                 create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);
333
334         /* Locate header for our buffer within our page */
335         for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
336                 /* Do nothing */;
337         get_bh(bh);
338
339         if (!buffer_mapped(bh))
340                 map_bh(bh, sdp->sd_vfs, blkno);
341
342         unlock_page(page);
343         mark_page_accessed(page);
344         page_cache_release(page);
345
346         return bh;
347 }
348
349 static void meta_prep_new(struct buffer_head *bh)
350 {
351         struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
352
353         lock_buffer(bh);
354         clear_buffer_dirty(bh);
355         set_buffer_uptodate(bh);
356         unlock_buffer(bh);
357
358         mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
359 }
360
361 /**
362  * gfs2_meta_new - Get a block
363  * @gl: The glock associated with this block
364  * @blkno: The block number
365  *
366  * Returns: The buffer
367  */
368
369 struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, uint64_t blkno)
370 {
371         struct buffer_head *bh;
372         bh = getbuf(gl->gl_sbd, gl->gl_aspace, blkno, CREATE);
373         meta_prep_new(bh);
374         return bh;
375 }
376
377 /**
378  * gfs2_meta_read - Read a block from disk
379  * @gl: The glock covering the block
380  * @blkno: The block number
381  * @flags: flags to gfs2_dreread()
382  * @bhp: the place where the buffer is returned (NULL on failure)
383  *
384  * Returns: errno
385  */
386
387 int gfs2_meta_read(struct gfs2_glock *gl, uint64_t blkno, int flags,
388                    struct buffer_head **bhp)
389 {
390         int error;
391
392         *bhp = getbuf(gl->gl_sbd, gl->gl_aspace, blkno, CREATE);
393         error = gfs2_meta_reread(gl->gl_sbd, *bhp, flags);
394         if (error)
395                 brelse(*bhp);
396
397         return error;
398 }
399
400 /**
401  * gfs2_meta_reread - Reread a block from disk
402  * @sdp: the filesystem
403  * @bh: The block to read
404  * @flags: Flags that control the read
405  *
406  * Returns: errno
407  */
408
409 int gfs2_meta_reread(struct gfs2_sbd *sdp, struct buffer_head *bh, int flags)
410 {
411         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
412                 return -EIO;
413
414         if (flags & DIO_FORCE)
415                 clear_buffer_uptodate(bh);
416
417         if ((flags & DIO_START) && !buffer_uptodate(bh))
418                 ll_rw_block(READ, 1, &bh);
419
420         if (flags & DIO_WAIT) {
421                 wait_on_buffer(bh);
422
423                 if (!buffer_uptodate(bh)) {
424                         struct gfs2_trans *tr = current->journal_info;
425                         if (tr && tr->tr_touched)
426                                 gfs2_io_error_bh(sdp, bh);
427                         return -EIO;
428                 }
429                 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
430                         return -EIO;
431         }
432
433         return 0;
434 }
435
436 /**
437  * gfs2_attach_bufdata - attach a struct gfs2_bufdata structure to a buffer
438  * @gl: the glock the buffer belongs to
439  * @bh: The buffer to be attached to
440  * @meta: Flag to indicate whether its metadata or not
441  */
442
443 void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
444                          int meta)
445 {
446         struct gfs2_bufdata *bd;
447
448         if (meta)
449                 lock_page(bh->b_page);
450
451         if (bh->b_private) {
452                 if (meta)
453                         unlock_page(bh->b_page);
454                 return;
455         }
456
457         bd = kmem_cache_alloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL),
458         memset(bd, 0, sizeof(struct gfs2_bufdata));
459         bd->bd_bh = bh;
460         bd->bd_gl = gl;
461
462         INIT_LIST_HEAD(&bd->bd_list_tr);
463         if (meta) {
464                 lops_init_le(&bd->bd_le, &gfs2_buf_lops);
465         } else {
466                 lops_init_le(&bd->bd_le, &gfs2_databuf_lops);
467                 get_bh(bh);
468         }
469         bh->b_private = bd;
470
471         if (meta)
472                 unlock_page(bh->b_page);
473 }
474
475 /**
476  * gfs2_pin - Pin a buffer in memory
477  * @sdp: the filesystem the buffer belongs to
478  * @bh: The buffer to be pinned
479  *
480  */
481
482 void gfs2_pin(struct gfs2_sbd *sdp, struct buffer_head *bh)
483 {
484         struct gfs2_bufdata *bd = bh->b_private;
485
486         gfs2_assert_withdraw(sdp, test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags));
487
488         if (test_set_buffer_pinned(bh))
489                 gfs2_assert_withdraw(sdp, 0);
490
491         wait_on_buffer(bh);
492
493         /* If this buffer is in the AIL and it has already been written
494            to in-place disk block, remove it from the AIL. */
495
496         gfs2_log_lock(sdp);
497         if (bd->bd_ail && !buffer_in_io(bh))
498                 list_move(&bd->bd_ail_st_list, &bd->bd_ail->ai_ail2_list);
499         gfs2_log_unlock(sdp);
500
501         clear_buffer_dirty(bh);
502         wait_on_buffer(bh);
503
504         if (!buffer_uptodate(bh))
505                 gfs2_io_error_bh(sdp, bh);
506
507         get_bh(bh);
508 }
509
510 /**
511  * gfs2_unpin - Unpin a buffer
512  * @sdp: the filesystem the buffer belongs to
513  * @bh: The buffer to unpin
514  * @ai:
515  *
516  */
517
518 void gfs2_unpin(struct gfs2_sbd *sdp, struct buffer_head *bh,
519                 struct gfs2_ail *ai)
520 {
521         struct gfs2_bufdata *bd = bh->b_private;
522
523         gfs2_assert_withdraw(sdp, buffer_uptodate(bh));
524
525         if (!buffer_pinned(bh))
526                 gfs2_assert_withdraw(sdp, 0);
527
528         mark_buffer_dirty(bh);
529         clear_buffer_pinned(bh);
530
531         gfs2_log_lock(sdp);
532         if (bd->bd_ail) {
533                 list_del(&bd->bd_ail_st_list);
534                 brelse(bh);
535         } else {
536                 struct gfs2_glock *gl = bd->bd_gl;
537                 list_add(&bd->bd_ail_gl_list, &gl->gl_ail_list);
538                 atomic_inc(&gl->gl_ail_count);
539         }
540         bd->bd_ail = ai;
541         list_add(&bd->bd_ail_st_list, &ai->ai_ail1_list);
542         gfs2_log_unlock(sdp);
543 }
544
545 /**
546  * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
547  * @ip: the inode who owns the buffers
548  * @bstart: the first buffer in the run
549  * @blen: the number of buffers in the run
550  *
551  */
552
553 void gfs2_meta_wipe(struct gfs2_inode *ip, uint64_t bstart, uint32_t blen)
554 {
555         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
556         struct inode *aspace = ip->i_gl->gl_aspace;
557         struct buffer_head *bh;
558
559         while (blen) {
560                 bh = getbuf(sdp, aspace, bstart, NO_CREATE);
561                 if (bh) {
562                         struct gfs2_bufdata *bd = bh->b_private;
563
564                         if (test_clear_buffer_pinned(bh)) {
565                                 struct gfs2_trans *tr = current->journal_info;
566                                 gfs2_log_lock(sdp);
567                                 list_del_init(&bd->bd_le.le_list);
568                                 gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
569                                 sdp->sd_log_num_buf--;
570                                 gfs2_log_unlock(sdp);
571                                 tr->tr_num_buf_rm++;
572                                 brelse(bh);
573                         }
574                         if (bd) {
575                                 gfs2_log_lock(sdp);
576                                 if (bd->bd_ail) {
577                                         uint64_t blkno = bh->b_blocknr;
578                                         bd->bd_ail = NULL;
579                                         list_del(&bd->bd_ail_st_list);
580                                         list_del(&bd->bd_ail_gl_list);
581                                         atomic_dec(&bd->bd_gl->gl_ail_count);
582                                         brelse(bh);
583                                         gfs2_log_unlock(sdp);
584                                         gfs2_trans_add_revoke(sdp, blkno);
585                                 } else
586                                         gfs2_log_unlock(sdp);
587                         }
588
589                         lock_buffer(bh);
590                         clear_buffer_dirty(bh);
591                         clear_buffer_uptodate(bh);
592                         unlock_buffer(bh);
593
594                         brelse(bh);
595                 }
596
597                 bstart++;
598                 blen--;
599         }
600 }
601
602 /**
603  * gfs2_meta_cache_flush - get rid of any references on buffers for this inode
604  * @ip: The GFS2 inode
605  *
606  * This releases buffers that are in the most-recently-used array of
607  * blocks used for indirect block addressing for this inode.
608  */
609
610 void gfs2_meta_cache_flush(struct gfs2_inode *ip)
611 {
612         struct buffer_head **bh_slot;
613         unsigned int x;
614
615         spin_lock(&ip->i_spin);
616
617         for (x = 0; x < GFS2_MAX_META_HEIGHT; x++) {
618                 bh_slot = &ip->i_cache[x];
619                 if (!*bh_slot)
620                         break;
621                 brelse(*bh_slot);
622                 *bh_slot = NULL;
623         }
624
625         spin_unlock(&ip->i_spin);
626 }
627
628 /**
629  * gfs2_meta_indirect_buffer - Get a metadata buffer
630  * @ip: The GFS2 inode
631  * @height: The level of this buf in the metadata (indir addr) tree (if any)
632  * @num: The block number (device relative) of the buffer
633  * @new: Non-zero if we may create a new buffer
634  * @bhp: the buffer is returned here
635  *
636  * Try to use the gfs2_inode's MRU metadata tree cache.
637  *
638  * Returns: errno
639  */
640
641 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, uint64_t num,
642                               int new, struct buffer_head **bhp)
643 {
644         struct buffer_head *bh, **bh_slot = ip->i_cache + height;
645         int error;
646
647         spin_lock(&ip->i_spin);
648         bh = *bh_slot;
649         if (bh) {
650                 if (bh->b_blocknr == num)
651                         get_bh(bh);
652                 else
653                         bh = NULL;
654         }
655         spin_unlock(&ip->i_spin);
656
657         if (bh) {
658                 if (new)
659                         meta_prep_new(bh);
660                 else {
661                         error = gfs2_meta_reread(GFS2_SB(&ip->i_inode), bh,
662                                                  DIO_START | DIO_WAIT);
663                         if (error) {
664                                 brelse(bh);
665                                 return error;
666                         }
667                 }
668         } else {
669                 if (new)
670                         bh = gfs2_meta_new(ip->i_gl, num);
671                 else {
672                         error = gfs2_meta_read(ip->i_gl, num,
673                                                DIO_START | DIO_WAIT, &bh);
674                         if (error)
675                                 return error;
676                 }
677
678                 spin_lock(&ip->i_spin);
679                 if (*bh_slot != bh) {
680                         brelse(*bh_slot);
681                         *bh_slot = bh;
682                         get_bh(bh);
683                 }
684                 spin_unlock(&ip->i_spin);
685         }
686
687         if (new) {
688                 if (gfs2_assert_warn(GFS2_SB(&ip->i_inode), height)) {
689                         brelse(bh);
690                         return -EIO;
691                 }
692                 gfs2_trans_add_bh(ip->i_gl, bh, 1);
693                 gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
694                 gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
695
696         } else if (gfs2_metatype_check(GFS2_SB(&ip->i_inode), bh,
697                              (height) ? GFS2_METATYPE_IN : GFS2_METATYPE_DI)) {
698                 brelse(bh);
699                 return -EIO;
700         }
701
702         *bhp = bh;
703
704         return 0;
705 }
706
707 /**
708  * gfs2_meta_ra - start readahead on an extent of a file
709  * @gl: the glock the blocks belong to
710  * @dblock: the starting disk block
711  * @extlen: the number of blocks in the extent
712  *
713  */
714
715 void gfs2_meta_ra(struct gfs2_glock *gl, uint64_t dblock, uint32_t extlen)
716 {
717         struct gfs2_sbd *sdp = gl->gl_sbd;
718         struct inode *aspace = gl->gl_aspace;
719         struct buffer_head *first_bh, *bh;
720         uint32_t max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
721                           sdp->sd_sb.sb_bsize_shift;
722         int error;
723
724         if (!extlen || !max_ra)
725                 return;
726         if (extlen > max_ra)
727                 extlen = max_ra;
728
729         first_bh = getbuf(sdp, aspace, dblock, CREATE);
730
731         if (buffer_uptodate(first_bh))
732                 goto out;
733         if (!buffer_locked(first_bh)) {
734                 error = gfs2_meta_reread(sdp, first_bh, DIO_START);
735                 if (error)
736                         goto out;
737         }
738
739         dblock++;
740         extlen--;
741
742         while (extlen) {
743                 bh = getbuf(sdp, aspace, dblock, CREATE);
744
745                 if (!buffer_uptodate(bh) && !buffer_locked(bh)) {
746                         error = gfs2_meta_reread(sdp, bh, DIO_START);
747                         brelse(bh);
748                         if (error)
749                                 goto out;
750                 } else
751                         brelse(bh);
752
753                 dblock++;
754                 extlen--;
755
756                 if (buffer_uptodate(first_bh))
757                         break;
758         }
759
760  out:
761         brelse(first_bh);
762 }
763
764 /**
765  * gfs2_meta_syncfs - sync all the buffers in a filesystem
766  * @sdp: the filesystem
767  *
768  */
769
770 void gfs2_meta_syncfs(struct gfs2_sbd *sdp)
771 {
772         gfs2_log_flush(sdp, NULL);
773         for (;;) {
774                 gfs2_ail1_start(sdp, DIO_ALL);
775                 if (gfs2_ail1_empty(sdp, DIO_ALL))
776                         break;
777                 msleep(10);
778         }
779 }
780