aboutsummaryrefslogtreecommitdiffstats
path: root/fs/jfs/super.c
blob: 314bb4ff1ba8a185715c8979feee658613eb6f13 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
/*
 *   Copyright (C) International Business Machines Corp., 2000-2004
 *   Portions Copyright (C) Christoph Hellwig, 2001-2002
 *
 *   This program is free software;  you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *   the GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program;  if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/fs.h>
#include <linux/module.h>
#include <linux/parser.h>
#include <linux/completion.h>
#include <linux/vfs.h>
#include <linux/mount.h>
#include <linux/moduleparam.h>
#include <linux/kthread.h>
#include <linux/posix_acl.h>
#include <linux/buffer_head.h>
#include <linux/exportfs.h>
#include <asm/uaccess.h>
#include <linux/seq_file.h>

#include "jfs_incore.h"
#include "jfs_filsys.h"
#include "jfs_inode.h"
#include "jfs_metapage.h"
#include "jfs_superblock.h"
#include "jfs_dmap.h"
#include "jfs_imap.h"
#include "jfs_acl.h"
#include "jfs_debug.h"

MODULE_DESCRIPTION("The Journaled Filesystem (JFS)");
MODULE_AUTHOR("Steve Best/Dave Kleikamp/Barry Arndt, IBM");
MODULE_LICENSE("GPL");

static struct kmem_cache * jfs_inode_cachep;

static const struct super_operations jfs_super_operations;
static const struct export_operations jfs_export_operations;
static struct file_system_type jfs_fs_type;

#define MAX_COMMIT_THREADS 64
static int commit_threads = 0;
module_param(commit_threads, int, 0);
MODULE_PARM_DESC(commit_threads, "Number of commit threads");

static struct task_struct *jfsCommitThread[MAX_COMMIT_THREADS];
struct task_struct *jfsIOthread;
struct task_struct *jfsSyncThread;

#ifdef CONFIG_JFS_DEBUG
int jfsloglevel = JFS_LOGLEVEL_WARN;
module_param(jfsloglevel, int, 0644);
MODULE_PARM_DESC(jfsloglevel, "Specify JFS loglevel (0, 1 or 2)");
#endif

static void jfs_handle_error(struct super_block *sb)
{
	struct jfs_sb_info *sbi = JFS_SBI(sb);

	if (sb->s_flags & MS_RDONLY)
		return;

	updateSuper(sb, FM_DIRTY);

	if (sbi->flag & JFS_ERR_PANIC)
		panic("JFS (device %s): panic forced after error\n",
			sb->s_id);
	else if (sbi->flag & JFS_ERR_REMOUNT_RO) {
		jfs_err("ERROR: (device %s): remounting filesystem "
			"as read-only\n",
			sb->s_id);
		sb->s_flags |= MS_RDONLY;
	}

	/* nothing is done for continue beyond marking the superblock dirty */
}

void jfs_error(struct super_block *sb, const char * function, ...)
{
	static char error_buf[256];
	va_list args;

	va_start(args, function);
	vsnprintf(error_buf, sizeof(error_buf), function, args);
	va_end(args);

	printk(KERN_ERR "ERROR: (device %s): %s\n", sb->s_id, error_buf);

	jfs_handle_error(sb);
}

static struct inode *jfs_alloc_inode(struct super_block *sb)
{
	struct jfs_inode_info *jfs_inode;

	jfs_inode = kmem_cache_alloc(jfs_inode_cachep, GFP_NOFS);
	if (!jfs_inode)
		return NULL;
	return &jfs_inode->vfs_inode;
}

static void jfs_destroy_inode(struct inode *inode)
{
	struct jfs_inode_info *ji = JFS_IP(inode);

	BUG_ON(!list_empty(&ji->anon_inode_list));

	spin_lock_irq(&ji->ag_lock);
	if (ji->active_ag != -1) {
		struct bmap *bmap = JFS_SBI(inode->i_sb)->bmap;
		atomic_dec(&bmap->db_active[ji->active_ag]);
		ji->active_ag = -1;
	}
	spin_unlock_irq(&ji->ag_lock);

#ifdef CONFIG_JFS_POSIX_ACL
	if (ji->i_acl != JFS_ACL_NOT_CACHED) {
		posix_acl_release(ji->i_acl);
		ji->i_acl = JFS_ACL_NOT_CACHED;
	}
	if (ji->i_default_acl != JFS_ACL_NOT_CACHED) {
		posix_acl_release(ji->i_default_acl);
		ji->i_default_acl = JFS_ACL_NOT_CACHED;
	}
#endif

	kmem_cache_free(jfs_inode_cachep, ji);
}

static int jfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
	struct jfs_sb_info *sbi = JFS_SBI(dentry->d_sb);
	s64 maxinodes;
	struct inomap *imap = JFS_IP(sbi->ipimap)->i_imap;

	jfs_info("In jfs_statfs");
	buf->f_type = JFS_SUPER_MAGIC;
	buf->f_bsize = sbi->bsize;
	buf->f_blocks = sbi->bmap->db_mapsize;
	buf->f_bfree = sbi->bmap->db_nfree;
	buf->f_bavail = sbi->bmap->db_nfree;
	/*
	 * If we really return the number of allocated & free inodes, some
	 * applications will fail because they won't see enough free inodes.
	 * We'll try to calculate some guess as to how may inodes we can
	 * really allocate
	 *
	 * buf->f_files = atomic_read(&imap->im_numinos);
	 * buf->f_ffree = atomic_read(&imap->im_numfree);
	 */
	maxinodes = min((s64) atomic_read(&imap->im_numinos) +
			((sbi->bmap->db_nfree >> imap->im_l2nbperiext)
			 << L2INOSPEREXT), (s64) 0xffffffffLL);
	buf->f_files = maxinodes;
	buf->f_ffree = maxinodes - (atomic_read(&imap->im_numinos) -
				    atomic_read(&imap->im_numfree));

	buf->f_namelen = JFS_NAME_MAX;
	return 0;
}

static void jfs_put_super(struct super_block *sb)
{
	struct jfs_sb_info *sbi = JFS_SBI(sb);
	int rc;

	jfs_info("In jfs_put_super");
	rc = jfs_umount(sb);
	if (rc)
		jfs_err("jfs_umount failed with return code %d", rc);
	if (sbi->nls_tab)
		unload_nls(sbi->nls_tab);
	sbi->nls_tab = NULL;

	truncate_inode_pages(sbi->direct_inode->i_mapping, 0);
	iput(sbi->direct_inode);
	sbi->direct_inode = NULL;

	kfree(sbi);
}

enum {
	Opt_integrity, Opt_nointegrity, Opt_iocharset, Opt_resize,
	Opt_resize_nosize, Opt_errors, Opt_ignore, Opt_err, Opt_quota,
	Opt_usrquota, Opt_grpquota, Opt_uid, Opt_gid, Opt_umask
};

static match_table_t tokens = {
	{Opt_integrity, "integrity"},
	{Opt_nointegrity, "nointegrity"},
	{Opt_iocharset, "iocharset=%s"},
	{Opt_resize, "resize=%u"},
	{Opt_resize_nosize, "resize"},
	{Opt_errors, "errors=%s"},
	{Opt_ignore, "noquota"},
	{Opt_ignore, "quota"},
	{Opt_usrquota, "usrquota"},
	{Opt_grpquota, "grpquota"},
	{Opt_uid, "uid=%u"},
	{Opt_gid, "gid=%u"},
	{Opt_umask, "umask=%u"},
	{Opt_err, NULL}
};

static int parse_options(char *options, struct super_block *sb, s64 *newLVSize,
			 int *flag)
{
	void *nls_map = (void *)-1;	/* -1: no change;  NULL: none */
	char *p;
	struct jfs_sb_info *sbi = JFS_SBI(sb);

	*newLVSize = 0;

	if (!options)
		return 1;

	while ((p = strsep(&options, ",")) != NULL) {
		substring_t args[MAX_OPT_ARGS];
		int token;
		if (!*p)
			continue;

		token = match_token(p, tokens, args);
		switch (token) {
		case Opt_integrity:
			*flag &= ~JFS_NOINTEGRITY;
			break;
		case Opt_nointegrity:
			*flag |= JFS_NOINTEGRITY;
			break;
		case Opt_ignore:
			/* Silently ignore the quota options */
			/* Don't do anything ;-) */
			break;
		case Opt_iocharset:
			if (nls_map && nls_map != (void *) -1)
				unload_nls(nls_map);
			if (!strcmp(args[0].from, "none"))
				nls_map = NULL;
			else {
				nls_map = load_nls(args[0].from);
				if (!nls_map) {
					printk(KERN_ERR
					       "JFS: charset not found\n");
					goto cleanup;
				}
			}
			break;
		case Opt_resize:
		{
			char *resize = args[0].from;
			*newLVSize = simple_strtoull(resize, &resize, 0);
			break;
		}
		case Opt_resize_nosize:
		{
			*newLVSize = sb->s_bdev->bd_inode->i_size >>
				sb->s_blocksize_bits;
			if (*newLVSize == 0)
				printk(KERN_ERR
				       "JFS: Cannot determine volume size\n");
			break;
		}
		case Opt_errors:
		{
			char *errors = args[0].from;
			if (!errors || !*errors)
				goto cleanup;
			if (!strcmp(errors, "continue")) {
				*flag &= ~JFS_ERR_REMOUNT_RO;
				*flag &= ~JFS_ERR_PANIC;
				*flag |= JFS_ERR_CONTINUE;
			} else if (!strcmp(errors, "remount-ro")) {
				*flag &= ~JFS_ERR_CONTINUE;
				*flag &= ~JFS_ERR_PANIC;
				*flag |= JFS_ERR_REMOUNT_RO;
			} else if (!strcmp(errors, "panic")) {
				*flag &= ~JFS_ERR_CONTINUE;
				*flag &= ~JFS_ERR_REMOUNT_RO;
				*flag |= JFS_ERR_PANIC;
			} else {
				printk(KERN_ERR
				       "JFS: %s is an invalid error handler\n",
				       errors);
				goto cleanup;
			}
			break;
		}

#ifdef CONFIG_QUOTA
		case Opt_quota:
		case Opt_usrquota:
			*flag |= JFS_USRQUOTA;
			break;
		case Opt_grpquota:
			*flag |= JFS_GRPQUOTA;
			break;
#else
		case Opt_usrquota:
		case Opt_grpquota:
		case Opt_quota:
			printk(KERN_ERR
			       "JFS: quota operations not supported\n");
			break;
#endif
		case Opt_uid:
		{
			char *uid = args[0].from;
			sbi->uid = simple_strtoul(uid, &uid, 0);
			break;
		}
		case Opt_gid:
		{
			char *gid = args[0].from;
			sbi->gid = simple_strtoul(gid, &gid, 0);
			break;
		}
		case Opt_umask:
		{
			char *umask = args[0].from;
			sbi->umask = simple_strtoul(umask, &umask, 8);
			if (sbi->umask & ~0777) {
				printk(KERN_ERR
				       "JFS: Invalid value of umask\n");
				goto cleanup;
			}
			break;
		}
		default:
			printk("jfs: Unrecognized mount option \"%s\" "
					" or missing value\n", p);
			goto cleanup;
		}
	}

	if (nls_map != (void *) -1) {
		/* Discard old (if remount) */
		if (sbi->nls_tab)
			unload_nls(sbi->nls_tab);
		sbi->nls_tab = nls_map;
	}
	return 1;

cleanup:
	if (nls_map && nls_map != (void *) -1)
		unload_nls(nls_map);
	return 0;
}

static int jfs_remount(struct super_block *sb, int *flags, char *data)
{
	s64 newLVSize = 0;
	int rc = 0;
	int flag = JFS_SBI(sb)->flag;

	if (!parse_options(data, sb, &newLVSize, &flag)) {
		return -EINVAL;
	}
	if (newLVSize) {
		if (sb->s_flags & MS_RDONLY) {
			printk(KERN_ERR
		  "JFS: resize requires volume to be mounted read-write\n");
			return -EROFS;
		}
		rc = jfs_extendfs(sb, newLVSize, 0);
		if (rc)
			return rc;
	}

	if ((sb->s_flags & MS_RDONLY) && !(*flags & MS_RDONLY)) {
		/*
		 * Invalidate any previously read metadata.  fsck may have
		 * changed the on-disk data since we mounted r/o
		 */
		truncate_inode_pages(JFS_SBI(sb)->direct_inode->i_mapping, 0);

		JFS_SBI(sb)->flag = flag;
		return jfs_mount_rw(sb, 1);
	}
	if ((!(sb->s_flags & MS_RDONLY)) && (*flags & MS_RDONLY)) {
		rc = jfs_umount_rw(sb);
		JFS_SBI(sb)->flag = flag;
		return rc;
	}
	if ((JFS_SBI(sb)->flag & JFS_NOINTEGRITY) != (flag & JFS_NOINTEGRITY))
		if (!(sb->s_flags & MS_RDONLY)) {
			rc = jfs_umount_rw(sb);
			if (rc)
				return rc;
			JFS_SBI(sb)->flag = flag;
			return jfs_mount_rw(sb, 1);
		}
	JFS_SBI(sb)->flag = flag;

	return 0;
}

static int jfs_fill_super(struct super_block *sb, void *data, int silent)
{
	struct jfs_sb_info *sbi;
	struct inode *inode;
	int rc;
	s64 newLVSize = 0;
	int flag;

	jfs_info("In jfs_read_super: s_flags=0x%lx", sb->s_flags);

	if (!new_valid_dev(sb->s_bdev->bd_dev))
		return -EOVERFLOW;

	sbi = kzalloc(sizeof (struct jfs_sb_info), GFP_KERNEL);
	if (!sbi)
		return -ENOMEM;
	sb->s_fs_info = sbi;
	sbi->sb = sb;
	sbi->uid = sbi->gid = sbi->umask = -1;

	/* initialize the mount flag and determine the default error handler */
	flag = JFS_ERR_REMOUNT_RO;

	if (!parse_options((char *) data, sb, &newLVSize, &flag)) {
		kfree(sbi);
		return -EINVAL;
	}
	sbi->flag = flag;

#ifdef CONFIG_JFS_POSIX_ACL
	sb->s_flags |= MS_POSIXACL;
#endif

	if (newLVSize) {
		printk(KERN_ERR "resize option for remount only\n");
		return -EINVAL;
	}

	/*
	 * Initialize blocksize to 4K.
	 */
	sb_set_blocksize(sb, PSIZE);

	/*
	 * Set method vectors.
	 */
	sb->s_op = &jfs_super_operations;
	sb->s_export_op = &jfs_export_operations;

	/*
	 * Initialize direct-mapping inode/address-space
	 */
	inode = new_inode(sb);
	if (inode == NULL)
		goto out_kfree;
	inode->i_ino = 0;
	inode->i_nlink = 1;
	inode->i_size = sb->s_bdev->bd_inode->i_size;
	inode->i_mapping->a_ops = &jfs_metapage_aops;
	insert_inode_hash(inode);
	mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);

	sbi->direct_inode = inode;

	rc = jfs_mount(sb);
	if (rc) {
		if (!silent) {
			jfs_err("jfs_mount failed w/return code = %d", rc);
		}
		goto out_mount_failed;
	}
	if (sb->s_flags & MS_RDONLY)
		sbi->log = NULL;
	else {
		rc = jfs_mount_rw(sb, 0);
		if (rc) {
			if (!silent) {
				jfs_err("jfs_mount_rw failed, return code = %d",
					rc);
			}
			goto out_no_rw;
		}
	}

	sb->s_magic = JFS_SUPER_MAGIC;

	inode = iget(sb, ROOT_I);
	if (!inode || is_bad_inode(inode))
		goto out_no_root;
	sb->s_root = d_alloc_root(inode);
	if (!sb->s_root)
		goto out_no_root;

	if (sbi->mntflag & JFS_OS2)
		sb->s_root->d_op = &jfs_ci_dentry_operations;

	/* logical blocks are represented by 40 bits in pxd_t, etc. */
	sb->s_maxbytes = ((u64) sb->s_blocksize) << 40;
#if BITS_PER_LONG == 32
	/*
	 * Page cache is indexed by long.
	 * I would use MAX_LFS_FILESIZE, but it's only half as big
	 */
	sb->s_maxbytes = min(((u64) PAGE_CACHE_SIZE << 32) - 1, sb->s_maxbytes);
#endif
	sb->s_time_gran = 1;
	return 0;

out_no_root:
	jfs_err("jfs_read_super: get root inode failed");
	if (inode)
		iput(inode);

out_no_rw:
	rc = jfs_umount(sb);
	if (rc) {
		jfs_err("jfs_umount failed with return code %d", rc);
	}
out_mount_failed:
	filemap_write_and_wait(sbi->direct_inode->i_mapping);
	truncate_inode_pages(sbi->direct_inode->i_mapping, 0);
	make_bad_inode(sbi->direct_inode);
	iput(sbi->direct_inode);
	sbi->direct_inode = NULL;
out_kfree:
	if (sbi->nls_tab)
		unload_nls(sbi->nls_tab);
	kfree(sbi);
	return -EINVAL;
}

static void jfs_write_super_lockfs(struct super_block *sb)
{
	struct jfs_sb_info *sbi = JFS_SBI(sb);
	struct jfs_log *log = sbi->log;

	if (!(sb->s_flags & MS_RDONLY)) {
		txQuiesce(sb);
		lmLogShutdown(log);
		updateSuper(sb, FM_CLEAN);
	}
}

static void jfs_unlockfs(struct super_block *sb)
{
	struct jfs_sb_info *sbi = JFS_SBI(sb);
	struct jfs_log *log = sbi->log;
	int rc = 0;

	if (!(sb->s_flags & MS_RDONLY)) {
		updateSuper(sb, FM_MOUNT);
		if ((rc = lmLogInit(log)))
			jfs_err("jfs_unlock failed with return code %d", rc);
		else
			txResume(sb);
	}
}

static int jfs_get_sb(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
	return get_sb_bdev(fs_type, flags, dev_name, data, jfs_fill_super,
			   mnt);
}

static int jfs_sync_fs(struct super_block *sb, int wait)
{
	struct jfs_log *log = JFS_SBI(sb)->log;

	/* log == NULL indicates read-only mount */
	if (log) {
		jfs_flush_journal(log, wait);
		jfs_syncpt(log, 0);
	}

	return 0;
}

static int jfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
{
	struct jfs_sb_info *sbi = JFS_SBI(vfs->mnt_sb);

	if (sbi->uid != -1)
		seq_printf(seq, ",uid=%d", sbi->uid);
	if (sbi->gid != -1)
		seq_printf(seq, ",gid=%d", sbi->gid);
	if (sbi->umask != -1)
		seq_printf(seq, ",umask=%03o", sbi->umask);
	if (sbi->flag & JFS_NOINTEGRITY)
		seq_puts(seq, ",nointegrity");

#ifdef CONFIG_QUOTA
	if (sbi->flag & JFS_USRQUOTA)
		seq_puts(seq, ",usrquota");

	if (sbi->flag & JFS_GRPQUOTA)
		seq_puts(seq, ",grpquota");
#endif

	return 0;
}

#ifdef CONFIG_QUOTA

/* Read data from quotafile - avoid pagecache and such because we cannot afford
 * acquiring the locks... As quota files are never truncated and quota code
 * itself serializes the operations (and noone else should touch the files)
 * we don't have to be afraid of races */
static ssize_t jfs_quota_read(struct super_block *sb, int type, char *data,
			      size_t len, loff_t off)
{
	struct inode *inode = sb_dqopt(sb)->files[type];
	sector_t blk = off >> sb->s_blocksize_bits;
	int err = 0;
	int offset = off & (sb->s_blocksize - 1);
	int tocopy;
	size_t toread;
	struct buffer_head tmp_bh;
	struct buffer_head *bh;
	loff_t i_size = i_size_read(inode);

	if (off > i_size)
		return 0;
	if (off+len > i_size)
		len = i_size-off;
	toread = len;
	while (toread > 0) {
		tocopy = sb->s_blocksize - offset < toread ?
				sb->s_blocksize - offset : toread;

		tmp_bh.b_state = 0;
		tmp_bh.b_size = 1 << inode->i_blkbits;
		err = jfs_get_block(inode, blk, &tmp_bh, 0);
		if (err)
			return err;
		if (!buffer_mapped(&tmp_bh))	/* A hole? */
			memset(data, 0, tocopy);
		else {
			bh = sb_bread(sb, tmp_bh.b_blocknr);
			if (!bh)
				return -EIO;
			memcpy(data, bh->b_data+offset, tocopy);
			brelse(bh);
		}
		offset = 0;
		toread -= tocopy;
		data += tocopy;
		blk++;
	}
	return len;
}

/* Write to quotafile */
static ssize_t jfs_quota_write(struct super_block *sb, int type,
			       const char *data, size_t len, loff_t off)
{
	struct inode *inode = sb_dqopt(sb)->files[type];
	sector_t blk = off >> sb->s_blocksize_bits;
	int err = 0;
	int offset = off & (sb->s_blocksize - 1);
	int tocopy;
	size_t towrite = len;
	struct buffer_head tmp_bh;
	struct buffer_head *bh;

	mutex_lock(&inode->i_mutex);
	while (towrite > 0) {
		tocopy = sb->s_blocksize - offset < towrite ?
				sb->s_blocksize - offset : towrite;

		tmp_bh.b_state = 0;
		tmp_bh.b_size = 1 << inode->i_blkbits;
		err = jfs_get_block(inode, blk, &tmp_bh, 1);
		if (err)
			goto out;
		if (offset || tocopy != sb->s_blocksize)
			bh = sb_bread(sb, tmp_bh.b_blocknr);
		else
			bh = sb_getblk(sb, tmp_bh.b_blocknr);
		if (!bh) {
			err = -EIO;
			goto out;
		}
		lock_buffer(bh);
		memcpy(bh->b_data+offset, data, tocopy);
		flush_dcache_page(bh->b_page);
		set_buffer_uptodate(bh);
		mark_buffer_dirty(bh);
		unlock_buffer(bh);
		brelse(bh);
		offset = 0;
		towrite -= tocopy;
		data += tocopy;
		blk++;
	}
out:
	if (len == towrite)
		return err;
	if (inode->i_size < off+len-towrite)
		i_size_write(inode, off+len-towrite);
	inode->i_version++;
	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
	mark_inode_dirty(inode);
	mutex_unlock(&inode->i_mutex);
	return len - towrite;
}

#endif

static const struct super_operations jfs_super_operations = {
	.alloc_inode	= jfs_alloc_inode,
	.destroy_inode	= jfs_destroy_inode,
	.read_inode	= jfs_read_inode,
	.dirty_inode	= jfs_dirty_inode,
	.write_inode	= jfs_write_inode,
	.delete_inode	= jfs_delete_inode,
	.put_super	= jfs_put_super,
	.sync_fs	= jfs_sync_fs,
	.write_super_lockfs = jfs_write_super_lockfs,
	.unlockfs       = jfs_unlockfs,
	.statfs		= jfs_statfs,
	.remount_fs	= jfs_remount,
	.show_options	= jfs_show_options,
#ifdef CONFIG_QUOTA
	.quota_read	= jfs_quota_read,
	.quota_write	= jfs_quota_write,
#endif
};

static const struct export_operations jfs_export_operations = {
	.fh_to_dentry	= jfs_fh_to_dentry,
	.fh_to_parent	= jfs_fh_to_parent,
	.get_parent	= jfs_get_parent,
};

static struct file_system_type jfs_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "jfs",
	.get_sb		= jfs_get_sb,
	.kill_sb	= kill_block_super,
	.fs_flags	= FS_REQUIRES_DEV,
};

static void init_once(struct kmem_cache *cachep, void *foo)
{
	struct jfs_inode_info *jfs_ip = (struct jfs_inode_info *) foo;

	memset(jfs_ip, 0, sizeof(struct jfs_inode_info));
	INIT_LIST_HEAD(&jfs_ip->anon_inode_list);
	init_rwsem(&jfs_ip->rdwrlock);
	mutex_init(&jfs_ip->commit_mutex);
	init_rwsem(&jfs_ip->xattr_sem);
	spin_lock_init(&jfs_ip->ag_lock);
	jfs_ip->active_ag = -1;
#ifdef CONFIG_JFS_POSIX_ACL
	jfs_ip->i_acl = JFS_ACL_NOT_CACHED;
	jfs_ip->i_default_acl = JFS_ACL_NOT_CACHED;
#endif
	inode_init_once(&jfs_ip->vfs_inode);
}

static int __init init_jfs_fs(void)
{
	int i;
	int rc;

	jfs_inode_cachep =
	    kmem_cache_create("jfs_ip", sizeof(struct jfs_inode_info), 0,
			    SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
			    init_once);
	if (jfs_inode_cachep == NULL)
		return -ENOMEM;

	/*
	 * Metapage initialization
	 */
	rc = metapage_init();
	if (rc) {
		jfs_err("metapage_init failed w/rc = %d", rc);
		goto free_slab;
	}

	/*
	 * Transaction Manager initialization
	 */
	rc = txInit();
	if (rc) {
		jfs_err("txInit failed w/rc = %d", rc);
		goto free_metapage;
	}

	/*
	 * I/O completion thread (endio)
	 */
	jfsIOthread = kthread_run(jfsIOWait, NULL, "jfsIO");
	if (IS_ERR(jfsIOthread)) {
		rc = PTR_ERR(jfsIOthread);
		jfs_err("init_jfs_fs: fork failed w/rc = %d", rc);
		goto end_txmngr;
	}

	if (commit_threads < 1)
		commit_threads = num_online_cpus();
	if (commit_threads > MAX_COMMIT_THREADS)
		commit_threads = MAX_COMMIT_THREADS;

	for (i = 0; i < commit_threads; i++) {
		jfsCommitThread[i] = kthread_run(jfs_lazycommit, NULL, "jfsCommit");
		if (IS_ERR(jfsCommitThread[i])) {
			rc = PTR_ERR(jfsCommitThread[i]);
			jfs_err("init_jfs_fs: fork failed w/rc = %d", rc);
			commit_threads = i;
			goto kill_committask;
		}
	}

	jfsSyncThread = kthread_run(jfs_sync, NULL, "jfsSync");
	if (IS_ERR(jfsSyncThread)) {
		rc = PTR_ERR(jfsSyncThread);
		jfs_err("init_jfs_fs: fork failed w/rc = %d", rc);
		goto kill_committask;
	}

#ifdef PROC_FS_JFS
	jfs_proc_init();
#endif

	return register_filesystem(&jfs_fs_type);

kill_committask:
	for (i = 0; i < commit_threads; i++)
		kthread_stop(jfsCommitThread[i]);
	kthread_stop(jfsIOthread);
end_txmngr:
	txExit();
free_metapage:
	metapage_exit();
free_slab:
	kmem_cache_destroy(jfs_inode_cachep);
	return rc;
}

static void __exit exit_jfs_fs(void)
{
	int i;

	jfs_info("exit_jfs_fs called");

	txExit();
	metapage_exit();

	kthread_stop(jfsIOthread);
	for (i = 0; i < commit_threads; i++)
		kthread_stop(jfsCommitThread[i]);
	kthread_stop(jfsSyncThread);
#ifdef PROC_FS_JFS
	jfs_proc_clean();
#endif
	unregister_filesystem(&jfs_fs_type);
	kmem_cache_destroy(jfs_inode_cachep);
}

module_init(init_jfs_fs)
module_exit(exit_jfs_fs)