xref: /linux/fs/jfs/super.c (revision e27ecdd94d81e5bc3d1f68591701db5adb342f0d)
1 /*
2  *   Copyright (C) International Business Machines Corp., 2000-2004
3  *   Portions Copyright (C) Christoph Hellwig, 2001-2002
4  *
5  *   This program is free software;  you can redistribute it and/or modify
6  *   it under the terms of the GNU General Public License as published by
7  *   the Free Software Foundation; either version 2 of the License, or
8  *   (at your option) any later version.
9  *
10  *   This program is distributed in the hope that it will be useful,
11  *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
13  *   the GNU General Public License for more details.
14  *
15  *   You should have received a copy of the GNU General Public License
16  *   along with this program;  if not, write to the Free Software
17  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18  */
19 
20 #include <linux/fs.h>
21 #include <linux/module.h>
22 #include <linux/parser.h>
23 #include <linux/completion.h>
24 #include <linux/vfs.h>
25 #include <linux/quotaops.h>
26 #include <linux/mount.h>
27 #include <linux/moduleparam.h>
28 #include <linux/kthread.h>
29 #include <linux/posix_acl.h>
30 #include <linux/buffer_head.h>
31 #include <linux/exportfs.h>
32 #include <linux/crc32.h>
33 #include <asm/uaccess.h>
34 #include <linux/seq_file.h>
35 #include <linux/smp_lock.h>
36 
37 #include "jfs_incore.h"
38 #include "jfs_filsys.h"
39 #include "jfs_inode.h"
40 #include "jfs_metapage.h"
41 #include "jfs_superblock.h"
42 #include "jfs_dmap.h"
43 #include "jfs_imap.h"
44 #include "jfs_acl.h"
45 #include "jfs_debug.h"
46 
47 MODULE_DESCRIPTION("The Journaled Filesystem (JFS)");
48 MODULE_AUTHOR("Steve Best/Dave Kleikamp/Barry Arndt, IBM");
49 MODULE_LICENSE("GPL");
50 
51 static struct kmem_cache * jfs_inode_cachep;
52 
53 static const struct super_operations jfs_super_operations;
54 static const struct export_operations jfs_export_operations;
55 static struct file_system_type jfs_fs_type;
56 
57 #define MAX_COMMIT_THREADS 64
58 static int commit_threads = 0;
59 module_param(commit_threads, int, 0);
60 MODULE_PARM_DESC(commit_threads, "Number of commit threads");
61 
62 static struct task_struct *jfsCommitThread[MAX_COMMIT_THREADS];
63 struct task_struct *jfsIOthread;
64 struct task_struct *jfsSyncThread;
65 
66 #ifdef CONFIG_JFS_DEBUG
67 int jfsloglevel = JFS_LOGLEVEL_WARN;
68 module_param(jfsloglevel, int, 0644);
69 MODULE_PARM_DESC(jfsloglevel, "Specify JFS loglevel (0, 1 or 2)");
70 #endif
71 
72 static void jfs_handle_error(struct super_block *sb)
73 {
74 	struct jfs_sb_info *sbi = JFS_SBI(sb);
75 
76 	if (sb->s_flags & MS_RDONLY)
77 		return;
78 
79 	updateSuper(sb, FM_DIRTY);
80 
81 	if (sbi->flag & JFS_ERR_PANIC)
82 		panic("JFS (device %s): panic forced after error\n",
83 			sb->s_id);
84 	else if (sbi->flag & JFS_ERR_REMOUNT_RO) {
85 		jfs_err("ERROR: (device %s): remounting filesystem "
86 			"as read-only\n",
87 			sb->s_id);
88 		sb->s_flags |= MS_RDONLY;
89 	}
90 
91 	/* nothing is done for continue beyond marking the superblock dirty */
92 }
93 
94 void jfs_error(struct super_block *sb, const char * function, ...)
95 {
96 	static char error_buf[256];
97 	va_list args;
98 
99 	va_start(args, function);
100 	vsnprintf(error_buf, sizeof(error_buf), function, args);
101 	va_end(args);
102 
103 	printk(KERN_ERR "ERROR: (device %s): %s\n", sb->s_id, error_buf);
104 
105 	jfs_handle_error(sb);
106 }
107 
108 static struct inode *jfs_alloc_inode(struct super_block *sb)
109 {
110 	struct jfs_inode_info *jfs_inode;
111 
112 	jfs_inode = kmem_cache_alloc(jfs_inode_cachep, GFP_NOFS);
113 	if (!jfs_inode)
114 		return NULL;
115 	return &jfs_inode->vfs_inode;
116 }
117 
118 static void jfs_destroy_inode(struct inode *inode)
119 {
120 	struct jfs_inode_info *ji = JFS_IP(inode);
121 
122 	BUG_ON(!list_empty(&ji->anon_inode_list));
123 
124 	spin_lock_irq(&ji->ag_lock);
125 	if (ji->active_ag != -1) {
126 		struct bmap *bmap = JFS_SBI(inode->i_sb)->bmap;
127 		atomic_dec(&bmap->db_active[ji->active_ag]);
128 		ji->active_ag = -1;
129 	}
130 	spin_unlock_irq(&ji->ag_lock);
131 
132 #ifdef CONFIG_JFS_POSIX_ACL
133 	if (ji->i_acl != JFS_ACL_NOT_CACHED) {
134 		posix_acl_release(ji->i_acl);
135 		ji->i_acl = JFS_ACL_NOT_CACHED;
136 	}
137 	if (ji->i_default_acl != JFS_ACL_NOT_CACHED) {
138 		posix_acl_release(ji->i_default_acl);
139 		ji->i_default_acl = JFS_ACL_NOT_CACHED;
140 	}
141 #endif
142 
143 	kmem_cache_free(jfs_inode_cachep, ji);
144 }
145 
146 static int jfs_statfs(struct dentry *dentry, struct kstatfs *buf)
147 {
148 	struct jfs_sb_info *sbi = JFS_SBI(dentry->d_sb);
149 	s64 maxinodes;
150 	struct inomap *imap = JFS_IP(sbi->ipimap)->i_imap;
151 
152 	jfs_info("In jfs_statfs");
153 	buf->f_type = JFS_SUPER_MAGIC;
154 	buf->f_bsize = sbi->bsize;
155 	buf->f_blocks = sbi->bmap->db_mapsize;
156 	buf->f_bfree = sbi->bmap->db_nfree;
157 	buf->f_bavail = sbi->bmap->db_nfree;
158 	/*
159 	 * If we really return the number of allocated & free inodes, some
160 	 * applications will fail because they won't see enough free inodes.
161 	 * We'll try to calculate some guess as to how may inodes we can
162 	 * really allocate
163 	 *
164 	 * buf->f_files = atomic_read(&imap->im_numinos);
165 	 * buf->f_ffree = atomic_read(&imap->im_numfree);
166 	 */
167 	maxinodes = min((s64) atomic_read(&imap->im_numinos) +
168 			((sbi->bmap->db_nfree >> imap->im_l2nbperiext)
169 			 << L2INOSPEREXT), (s64) 0xffffffffLL);
170 	buf->f_files = maxinodes;
171 	buf->f_ffree = maxinodes - (atomic_read(&imap->im_numinos) -
172 				    atomic_read(&imap->im_numfree));
173 	buf->f_fsid.val[0] = (u32)crc32_le(0, sbi->uuid, sizeof(sbi->uuid)/2);
174 	buf->f_fsid.val[1] = (u32)crc32_le(0, sbi->uuid + sizeof(sbi->uuid)/2,
175 					sizeof(sbi->uuid)/2);
176 
177 	buf->f_namelen = JFS_NAME_MAX;
178 	return 0;
179 }
180 
181 static void jfs_put_super(struct super_block *sb)
182 {
183 	struct jfs_sb_info *sbi = JFS_SBI(sb);
184 	int rc;
185 
186 	jfs_info("In jfs_put_super");
187 
188 	lock_kernel();
189 
190 	rc = jfs_umount(sb);
191 	if (rc)
192 		jfs_err("jfs_umount failed with return code %d", rc);
193 	if (sbi->nls_tab)
194 		unload_nls(sbi->nls_tab);
195 	sbi->nls_tab = NULL;
196 
197 	truncate_inode_pages(sbi->direct_inode->i_mapping, 0);
198 	iput(sbi->direct_inode);
199 	sbi->direct_inode = NULL;
200 
201 	kfree(sbi);
202 
203 	unlock_kernel();
204 }
205 
206 enum {
207 	Opt_integrity, Opt_nointegrity, Opt_iocharset, Opt_resize,
208 	Opt_resize_nosize, Opt_errors, Opt_ignore, Opt_err, Opt_quota,
209 	Opt_usrquota, Opt_grpquota, Opt_uid, Opt_gid, Opt_umask
210 };
211 
212 static const match_table_t tokens = {
213 	{Opt_integrity, "integrity"},
214 	{Opt_nointegrity, "nointegrity"},
215 	{Opt_iocharset, "iocharset=%s"},
216 	{Opt_resize, "resize=%u"},
217 	{Opt_resize_nosize, "resize"},
218 	{Opt_errors, "errors=%s"},
219 	{Opt_ignore, "noquota"},
220 	{Opt_ignore, "quota"},
221 	{Opt_usrquota, "usrquota"},
222 	{Opt_grpquota, "grpquota"},
223 	{Opt_uid, "uid=%u"},
224 	{Opt_gid, "gid=%u"},
225 	{Opt_umask, "umask=%u"},
226 	{Opt_err, NULL}
227 };
228 
229 static int parse_options(char *options, struct super_block *sb, s64 *newLVSize,
230 			 int *flag)
231 {
232 	void *nls_map = (void *)-1;	/* -1: no change;  NULL: none */
233 	char *p;
234 	struct jfs_sb_info *sbi = JFS_SBI(sb);
235 
236 	*newLVSize = 0;
237 
238 	if (!options)
239 		return 1;
240 
241 	while ((p = strsep(&options, ",")) != NULL) {
242 		substring_t args[MAX_OPT_ARGS];
243 		int token;
244 		if (!*p)
245 			continue;
246 
247 		token = match_token(p, tokens, args);
248 		switch (token) {
249 		case Opt_integrity:
250 			*flag &= ~JFS_NOINTEGRITY;
251 			break;
252 		case Opt_nointegrity:
253 			*flag |= JFS_NOINTEGRITY;
254 			break;
255 		case Opt_ignore:
256 			/* Silently ignore the quota options */
257 			/* Don't do anything ;-) */
258 			break;
259 		case Opt_iocharset:
260 			if (nls_map && nls_map != (void *) -1)
261 				unload_nls(nls_map);
262 			if (!strcmp(args[0].from, "none"))
263 				nls_map = NULL;
264 			else {
265 				nls_map = load_nls(args[0].from);
266 				if (!nls_map) {
267 					printk(KERN_ERR
268 					       "JFS: charset not found\n");
269 					goto cleanup;
270 				}
271 			}
272 			break;
273 		case Opt_resize:
274 		{
275 			char *resize = args[0].from;
276 			*newLVSize = simple_strtoull(resize, &resize, 0);
277 			break;
278 		}
279 		case Opt_resize_nosize:
280 		{
281 			*newLVSize = sb->s_bdev->bd_inode->i_size >>
282 				sb->s_blocksize_bits;
283 			if (*newLVSize == 0)
284 				printk(KERN_ERR
285 				       "JFS: Cannot determine volume size\n");
286 			break;
287 		}
288 		case Opt_errors:
289 		{
290 			char *errors = args[0].from;
291 			if (!errors || !*errors)
292 				goto cleanup;
293 			if (!strcmp(errors, "continue")) {
294 				*flag &= ~JFS_ERR_REMOUNT_RO;
295 				*flag &= ~JFS_ERR_PANIC;
296 				*flag |= JFS_ERR_CONTINUE;
297 			} else if (!strcmp(errors, "remount-ro")) {
298 				*flag &= ~JFS_ERR_CONTINUE;
299 				*flag &= ~JFS_ERR_PANIC;
300 				*flag |= JFS_ERR_REMOUNT_RO;
301 			} else if (!strcmp(errors, "panic")) {
302 				*flag &= ~JFS_ERR_CONTINUE;
303 				*flag &= ~JFS_ERR_REMOUNT_RO;
304 				*flag |= JFS_ERR_PANIC;
305 			} else {
306 				printk(KERN_ERR
307 				       "JFS: %s is an invalid error handler\n",
308 				       errors);
309 				goto cleanup;
310 			}
311 			break;
312 		}
313 
314 #ifdef CONFIG_QUOTA
315 		case Opt_quota:
316 		case Opt_usrquota:
317 			*flag |= JFS_USRQUOTA;
318 			break;
319 		case Opt_grpquota:
320 			*flag |= JFS_GRPQUOTA;
321 			break;
322 #else
323 		case Opt_usrquota:
324 		case Opt_grpquota:
325 		case Opt_quota:
326 			printk(KERN_ERR
327 			       "JFS: quota operations not supported\n");
328 			break;
329 #endif
330 		case Opt_uid:
331 		{
332 			char *uid = args[0].from;
333 			sbi->uid = simple_strtoul(uid, &uid, 0);
334 			break;
335 		}
336 		case Opt_gid:
337 		{
338 			char *gid = args[0].from;
339 			sbi->gid = simple_strtoul(gid, &gid, 0);
340 			break;
341 		}
342 		case Opt_umask:
343 		{
344 			char *umask = args[0].from;
345 			sbi->umask = simple_strtoul(umask, &umask, 8);
346 			if (sbi->umask & ~0777) {
347 				printk(KERN_ERR
348 				       "JFS: Invalid value of umask\n");
349 				goto cleanup;
350 			}
351 			break;
352 		}
353 		default:
354 			printk("jfs: Unrecognized mount option \"%s\" "
355 					" or missing value\n", p);
356 			goto cleanup;
357 		}
358 	}
359 
360 	if (nls_map != (void *) -1) {
361 		/* Discard old (if remount) */
362 		if (sbi->nls_tab)
363 			unload_nls(sbi->nls_tab);
364 		sbi->nls_tab = nls_map;
365 	}
366 	return 1;
367 
368 cleanup:
369 	if (nls_map && nls_map != (void *) -1)
370 		unload_nls(nls_map);
371 	return 0;
372 }
373 
374 static int jfs_remount(struct super_block *sb, int *flags, char *data)
375 {
376 	s64 newLVSize = 0;
377 	int rc = 0;
378 	int flag = JFS_SBI(sb)->flag;
379 	int ret;
380 
381 	if (!parse_options(data, sb, &newLVSize, &flag)) {
382 		return -EINVAL;
383 	}
384 	lock_kernel();
385 	if (newLVSize) {
386 		if (sb->s_flags & MS_RDONLY) {
387 			printk(KERN_ERR
388 		  "JFS: resize requires volume to be mounted read-write\n");
389 			unlock_kernel();
390 			return -EROFS;
391 		}
392 		rc = jfs_extendfs(sb, newLVSize, 0);
393 		if (rc) {
394 			unlock_kernel();
395 			return rc;
396 		}
397 	}
398 
399 	if ((sb->s_flags & MS_RDONLY) && !(*flags & MS_RDONLY)) {
400 		/*
401 		 * Invalidate any previously read metadata.  fsck may have
402 		 * changed the on-disk data since we mounted r/o
403 		 */
404 		truncate_inode_pages(JFS_SBI(sb)->direct_inode->i_mapping, 0);
405 
406 		JFS_SBI(sb)->flag = flag;
407 		ret = jfs_mount_rw(sb, 1);
408 		unlock_kernel();
409 		return ret;
410 	}
411 	if ((!(sb->s_flags & MS_RDONLY)) && (*flags & MS_RDONLY)) {
412 		rc = jfs_umount_rw(sb);
413 		JFS_SBI(sb)->flag = flag;
414 		unlock_kernel();
415 		return rc;
416 	}
417 	if ((JFS_SBI(sb)->flag & JFS_NOINTEGRITY) != (flag & JFS_NOINTEGRITY))
418 		if (!(sb->s_flags & MS_RDONLY)) {
419 			rc = jfs_umount_rw(sb);
420 			if (rc) {
421 				unlock_kernel();
422 				return rc;
423 			}
424 			JFS_SBI(sb)->flag = flag;
425 			ret = jfs_mount_rw(sb, 1);
426 			unlock_kernel();
427 			return ret;
428 		}
429 	JFS_SBI(sb)->flag = flag;
430 
431 	unlock_kernel();
432 	return 0;
433 }
434 
435 static int jfs_fill_super(struct super_block *sb, void *data, int silent)
436 {
437 	struct jfs_sb_info *sbi;
438 	struct inode *inode;
439 	int rc;
440 	s64 newLVSize = 0;
441 	int flag, ret = -EINVAL;
442 
443 	jfs_info("In jfs_read_super: s_flags=0x%lx", sb->s_flags);
444 
445 	if (!new_valid_dev(sb->s_bdev->bd_dev))
446 		return -EOVERFLOW;
447 
448 	sbi = kzalloc(sizeof (struct jfs_sb_info), GFP_KERNEL);
449 	if (!sbi)
450 		return -ENOMEM;
451 	sb->s_fs_info = sbi;
452 	sbi->sb = sb;
453 	sbi->uid = sbi->gid = sbi->umask = -1;
454 
455 	/* initialize the mount flag and determine the default error handler */
456 	flag = JFS_ERR_REMOUNT_RO;
457 
458 	if (!parse_options((char *) data, sb, &newLVSize, &flag)) {
459 		kfree(sbi);
460 		return -EINVAL;
461 	}
462 	sbi->flag = flag;
463 
464 #ifdef CONFIG_JFS_POSIX_ACL
465 	sb->s_flags |= MS_POSIXACL;
466 #endif
467 
468 	if (newLVSize) {
469 		printk(KERN_ERR "resize option for remount only\n");
470 		return -EINVAL;
471 	}
472 
473 	/*
474 	 * Initialize blocksize to 4K.
475 	 */
476 	sb_set_blocksize(sb, PSIZE);
477 
478 	/*
479 	 * Set method vectors.
480 	 */
481 	sb->s_op = &jfs_super_operations;
482 	sb->s_export_op = &jfs_export_operations;
483 
484 	/*
485 	 * Initialize direct-mapping inode/address-space
486 	 */
487 	inode = new_inode(sb);
488 	if (inode == NULL) {
489 		ret = -ENOMEM;
490 		goto out_kfree;
491 	}
492 	inode->i_ino = 0;
493 	inode->i_nlink = 1;
494 	inode->i_size = sb->s_bdev->bd_inode->i_size;
495 	inode->i_mapping->a_ops = &jfs_metapage_aops;
496 	insert_inode_hash(inode);
497 	mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
498 
499 	sbi->direct_inode = inode;
500 
501 	rc = jfs_mount(sb);
502 	if (rc) {
503 		if (!silent) {
504 			jfs_err("jfs_mount failed w/return code = %d", rc);
505 		}
506 		goto out_mount_failed;
507 	}
508 	if (sb->s_flags & MS_RDONLY)
509 		sbi->log = NULL;
510 	else {
511 		rc = jfs_mount_rw(sb, 0);
512 		if (rc) {
513 			if (!silent) {
514 				jfs_err("jfs_mount_rw failed, return code = %d",
515 					rc);
516 			}
517 			goto out_no_rw;
518 		}
519 	}
520 
521 	sb->s_magic = JFS_SUPER_MAGIC;
522 
523 	inode = jfs_iget(sb, ROOT_I);
524 	if (IS_ERR(inode)) {
525 		ret = PTR_ERR(inode);
526 		goto out_no_rw;
527 	}
528 	sb->s_root = d_alloc_root(inode);
529 	if (!sb->s_root)
530 		goto out_no_root;
531 
532 	if (sbi->mntflag & JFS_OS2)
533 		sb->s_root->d_op = &jfs_ci_dentry_operations;
534 
535 	/* logical blocks are represented by 40 bits in pxd_t, etc. */
536 	sb->s_maxbytes = ((u64) sb->s_blocksize) << 40;
537 #if BITS_PER_LONG == 32
538 	/*
539 	 * Page cache is indexed by long.
540 	 * I would use MAX_LFS_FILESIZE, but it's only half as big
541 	 */
542 	sb->s_maxbytes = min(((u64) PAGE_CACHE_SIZE << 32) - 1, sb->s_maxbytes);
543 #endif
544 	sb->s_time_gran = 1;
545 	return 0;
546 
547 out_no_root:
548 	jfs_err("jfs_read_super: get root dentry failed");
549 	iput(inode);
550 
551 out_no_rw:
552 	rc = jfs_umount(sb);
553 	if (rc) {
554 		jfs_err("jfs_umount failed with return code %d", rc);
555 	}
556 out_mount_failed:
557 	filemap_write_and_wait(sbi->direct_inode->i_mapping);
558 	truncate_inode_pages(sbi->direct_inode->i_mapping, 0);
559 	make_bad_inode(sbi->direct_inode);
560 	iput(sbi->direct_inode);
561 	sbi->direct_inode = NULL;
562 out_kfree:
563 	if (sbi->nls_tab)
564 		unload_nls(sbi->nls_tab);
565 	kfree(sbi);
566 	return ret;
567 }
568 
569 static int jfs_freeze(struct super_block *sb)
570 {
571 	struct jfs_sb_info *sbi = JFS_SBI(sb);
572 	struct jfs_log *log = sbi->log;
573 
574 	if (!(sb->s_flags & MS_RDONLY)) {
575 		txQuiesce(sb);
576 		lmLogShutdown(log);
577 		updateSuper(sb, FM_CLEAN);
578 	}
579 	return 0;
580 }
581 
582 static int jfs_unfreeze(struct super_block *sb)
583 {
584 	struct jfs_sb_info *sbi = JFS_SBI(sb);
585 	struct jfs_log *log = sbi->log;
586 	int rc = 0;
587 
588 	if (!(sb->s_flags & MS_RDONLY)) {
589 		updateSuper(sb, FM_MOUNT);
590 		if ((rc = lmLogInit(log)))
591 			jfs_err("jfs_unlock failed with return code %d", rc);
592 		else
593 			txResume(sb);
594 	}
595 	return 0;
596 }
597 
598 static int jfs_get_sb(struct file_system_type *fs_type,
599 	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
600 {
601 	return get_sb_bdev(fs_type, flags, dev_name, data, jfs_fill_super,
602 			   mnt);
603 }
604 
605 static int jfs_sync_fs(struct super_block *sb, int wait)
606 {
607 	struct jfs_log *log = JFS_SBI(sb)->log;
608 
609 	/* log == NULL indicates read-only mount */
610 	if (log) {
611 		jfs_flush_journal(log, wait);
612 		jfs_syncpt(log, 0);
613 	}
614 
615 	return 0;
616 }
617 
618 static int jfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
619 {
620 	struct jfs_sb_info *sbi = JFS_SBI(vfs->mnt_sb);
621 
622 	if (sbi->uid != -1)
623 		seq_printf(seq, ",uid=%d", sbi->uid);
624 	if (sbi->gid != -1)
625 		seq_printf(seq, ",gid=%d", sbi->gid);
626 	if (sbi->umask != -1)
627 		seq_printf(seq, ",umask=%03o", sbi->umask);
628 	if (sbi->flag & JFS_NOINTEGRITY)
629 		seq_puts(seq, ",nointegrity");
630 	if (sbi->nls_tab)
631 		seq_printf(seq, ",iocharset=%s", sbi->nls_tab->charset);
632 	if (sbi->flag & JFS_ERR_CONTINUE)
633 		seq_printf(seq, ",errors=continue");
634 	if (sbi->flag & JFS_ERR_PANIC)
635 		seq_printf(seq, ",errors=panic");
636 
637 #ifdef CONFIG_QUOTA
638 	if (sbi->flag & JFS_USRQUOTA)
639 		seq_puts(seq, ",usrquota");
640 
641 	if (sbi->flag & JFS_GRPQUOTA)
642 		seq_puts(seq, ",grpquota");
643 #endif
644 
645 	return 0;
646 }
647 
648 #ifdef CONFIG_QUOTA
649 
650 /* Read data from quotafile - avoid pagecache and such because we cannot afford
651  * acquiring the locks... As quota files are never truncated and quota code
652  * itself serializes the operations (and noone else should touch the files)
653  * we don't have to be afraid of races */
654 static ssize_t jfs_quota_read(struct super_block *sb, int type, char *data,
655 			      size_t len, loff_t off)
656 {
657 	struct inode *inode = sb_dqopt(sb)->files[type];
658 	sector_t blk = off >> sb->s_blocksize_bits;
659 	int err = 0;
660 	int offset = off & (sb->s_blocksize - 1);
661 	int tocopy;
662 	size_t toread;
663 	struct buffer_head tmp_bh;
664 	struct buffer_head *bh;
665 	loff_t i_size = i_size_read(inode);
666 
667 	if (off > i_size)
668 		return 0;
669 	if (off+len > i_size)
670 		len = i_size-off;
671 	toread = len;
672 	while (toread > 0) {
673 		tocopy = sb->s_blocksize - offset < toread ?
674 				sb->s_blocksize - offset : toread;
675 
676 		tmp_bh.b_state = 0;
677 		tmp_bh.b_size = 1 << inode->i_blkbits;
678 		err = jfs_get_block(inode, blk, &tmp_bh, 0);
679 		if (err)
680 			return err;
681 		if (!buffer_mapped(&tmp_bh))	/* A hole? */
682 			memset(data, 0, tocopy);
683 		else {
684 			bh = sb_bread(sb, tmp_bh.b_blocknr);
685 			if (!bh)
686 				return -EIO;
687 			memcpy(data, bh->b_data+offset, tocopy);
688 			brelse(bh);
689 		}
690 		offset = 0;
691 		toread -= tocopy;
692 		data += tocopy;
693 		blk++;
694 	}
695 	return len;
696 }
697 
698 /* Write to quotafile */
699 static ssize_t jfs_quota_write(struct super_block *sb, int type,
700 			       const char *data, size_t len, loff_t off)
701 {
702 	struct inode *inode = sb_dqopt(sb)->files[type];
703 	sector_t blk = off >> sb->s_blocksize_bits;
704 	int err = 0;
705 	int offset = off & (sb->s_blocksize - 1);
706 	int tocopy;
707 	size_t towrite = len;
708 	struct buffer_head tmp_bh;
709 	struct buffer_head *bh;
710 
711 	mutex_lock(&inode->i_mutex);
712 	while (towrite > 0) {
713 		tocopy = sb->s_blocksize - offset < towrite ?
714 				sb->s_blocksize - offset : towrite;
715 
716 		tmp_bh.b_state = 0;
717 		tmp_bh.b_size = 1 << inode->i_blkbits;
718 		err = jfs_get_block(inode, blk, &tmp_bh, 1);
719 		if (err)
720 			goto out;
721 		if (offset || tocopy != sb->s_blocksize)
722 			bh = sb_bread(sb, tmp_bh.b_blocknr);
723 		else
724 			bh = sb_getblk(sb, tmp_bh.b_blocknr);
725 		if (!bh) {
726 			err = -EIO;
727 			goto out;
728 		}
729 		lock_buffer(bh);
730 		memcpy(bh->b_data+offset, data, tocopy);
731 		flush_dcache_page(bh->b_page);
732 		set_buffer_uptodate(bh);
733 		mark_buffer_dirty(bh);
734 		unlock_buffer(bh);
735 		brelse(bh);
736 		offset = 0;
737 		towrite -= tocopy;
738 		data += tocopy;
739 		blk++;
740 	}
741 out:
742 	if (len == towrite) {
743 		mutex_unlock(&inode->i_mutex);
744 		return err;
745 	}
746 	if (inode->i_size < off+len-towrite)
747 		i_size_write(inode, off+len-towrite);
748 	inode->i_version++;
749 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
750 	mark_inode_dirty(inode);
751 	mutex_unlock(&inode->i_mutex);
752 	return len - towrite;
753 }
754 
755 #endif
756 
757 static const struct super_operations jfs_super_operations = {
758 	.alloc_inode	= jfs_alloc_inode,
759 	.destroy_inode	= jfs_destroy_inode,
760 	.dirty_inode	= jfs_dirty_inode,
761 	.write_inode	= jfs_write_inode,
762 	.delete_inode	= jfs_delete_inode,
763 	.put_super	= jfs_put_super,
764 	.sync_fs	= jfs_sync_fs,
765 	.freeze_fs	= jfs_freeze,
766 	.unfreeze_fs	= jfs_unfreeze,
767 	.statfs		= jfs_statfs,
768 	.remount_fs	= jfs_remount,
769 	.show_options	= jfs_show_options,
770 #ifdef CONFIG_QUOTA
771 	.quota_read	= jfs_quota_read,
772 	.quota_write	= jfs_quota_write,
773 #endif
774 };
775 
776 static const struct export_operations jfs_export_operations = {
777 	.fh_to_dentry	= jfs_fh_to_dentry,
778 	.fh_to_parent	= jfs_fh_to_parent,
779 	.get_parent	= jfs_get_parent,
780 };
781 
782 static struct file_system_type jfs_fs_type = {
783 	.owner		= THIS_MODULE,
784 	.name		= "jfs",
785 	.get_sb		= jfs_get_sb,
786 	.kill_sb	= kill_block_super,
787 	.fs_flags	= FS_REQUIRES_DEV,
788 };
789 
790 static void init_once(void *foo)
791 {
792 	struct jfs_inode_info *jfs_ip = (struct jfs_inode_info *) foo;
793 
794 	memset(jfs_ip, 0, sizeof(struct jfs_inode_info));
795 	INIT_LIST_HEAD(&jfs_ip->anon_inode_list);
796 	init_rwsem(&jfs_ip->rdwrlock);
797 	mutex_init(&jfs_ip->commit_mutex);
798 	init_rwsem(&jfs_ip->xattr_sem);
799 	spin_lock_init(&jfs_ip->ag_lock);
800 	jfs_ip->active_ag = -1;
801 #ifdef CONFIG_JFS_POSIX_ACL
802 	jfs_ip->i_acl = JFS_ACL_NOT_CACHED;
803 	jfs_ip->i_default_acl = JFS_ACL_NOT_CACHED;
804 #endif
805 	inode_init_once(&jfs_ip->vfs_inode);
806 }
807 
808 static int __init init_jfs_fs(void)
809 {
810 	int i;
811 	int rc;
812 
813 	jfs_inode_cachep =
814 	    kmem_cache_create("jfs_ip", sizeof(struct jfs_inode_info), 0,
815 			    SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
816 			    init_once);
817 	if (jfs_inode_cachep == NULL)
818 		return -ENOMEM;
819 
820 	/*
821 	 * Metapage initialization
822 	 */
823 	rc = metapage_init();
824 	if (rc) {
825 		jfs_err("metapage_init failed w/rc = %d", rc);
826 		goto free_slab;
827 	}
828 
829 	/*
830 	 * Transaction Manager initialization
831 	 */
832 	rc = txInit();
833 	if (rc) {
834 		jfs_err("txInit failed w/rc = %d", rc);
835 		goto free_metapage;
836 	}
837 
838 	/*
839 	 * I/O completion thread (endio)
840 	 */
841 	jfsIOthread = kthread_run(jfsIOWait, NULL, "jfsIO");
842 	if (IS_ERR(jfsIOthread)) {
843 		rc = PTR_ERR(jfsIOthread);
844 		jfs_err("init_jfs_fs: fork failed w/rc = %d", rc);
845 		goto end_txmngr;
846 	}
847 
848 	if (commit_threads < 1)
849 		commit_threads = num_online_cpus();
850 	if (commit_threads > MAX_COMMIT_THREADS)
851 		commit_threads = MAX_COMMIT_THREADS;
852 
853 	for (i = 0; i < commit_threads; i++) {
854 		jfsCommitThread[i] = kthread_run(jfs_lazycommit, NULL, "jfsCommit");
855 		if (IS_ERR(jfsCommitThread[i])) {
856 			rc = PTR_ERR(jfsCommitThread[i]);
857 			jfs_err("init_jfs_fs: fork failed w/rc = %d", rc);
858 			commit_threads = i;
859 			goto kill_committask;
860 		}
861 	}
862 
863 	jfsSyncThread = kthread_run(jfs_sync, NULL, "jfsSync");
864 	if (IS_ERR(jfsSyncThread)) {
865 		rc = PTR_ERR(jfsSyncThread);
866 		jfs_err("init_jfs_fs: fork failed w/rc = %d", rc);
867 		goto kill_committask;
868 	}
869 
870 #ifdef PROC_FS_JFS
871 	jfs_proc_init();
872 #endif
873 
874 	return register_filesystem(&jfs_fs_type);
875 
876 kill_committask:
877 	for (i = 0; i < commit_threads; i++)
878 		kthread_stop(jfsCommitThread[i]);
879 	kthread_stop(jfsIOthread);
880 end_txmngr:
881 	txExit();
882 free_metapage:
883 	metapage_exit();
884 free_slab:
885 	kmem_cache_destroy(jfs_inode_cachep);
886 	return rc;
887 }
888 
889 static void __exit exit_jfs_fs(void)
890 {
891 	int i;
892 
893 	jfs_info("exit_jfs_fs called");
894 
895 	txExit();
896 	metapage_exit();
897 
898 	kthread_stop(jfsIOthread);
899 	for (i = 0; i < commit_threads; i++)
900 		kthread_stop(jfsCommitThread[i]);
901 	kthread_stop(jfsSyncThread);
902 #ifdef PROC_FS_JFS
903 	jfs_proc_clean();
904 #endif
905 	unregister_filesystem(&jfs_fs_type);
906 	kmem_cache_destroy(jfs_inode_cachep);
907 }
908 
909 module_init(init_jfs_fs)
910 module_exit(exit_jfs_fs)
911