xref: /linux/fs/jfs/super.c (revision f2ee442115c9b6219083c019939a9cc0c9abb2f8)
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 <linux/slab.h>
34 #include <asm/uaccess.h>
35 #include <linux/seq_file.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_i_callback(struct rcu_head *head)
119 {
120 	struct inode *inode = container_of(head, struct inode, i_rcu);
121 	struct jfs_inode_info *ji = JFS_IP(inode);
122 	INIT_LIST_HEAD(&inode->i_dentry);
123 	kmem_cache_free(jfs_inode_cachep, ji);
124 }
125 
126 static void jfs_destroy_inode(struct inode *inode)
127 {
128 	struct jfs_inode_info *ji = JFS_IP(inode);
129 
130 	BUG_ON(!list_empty(&ji->anon_inode_list));
131 
132 	spin_lock_irq(&ji->ag_lock);
133 	if (ji->active_ag != -1) {
134 		struct bmap *bmap = JFS_SBI(inode->i_sb)->bmap;
135 		atomic_dec(&bmap->db_active[ji->active_ag]);
136 		ji->active_ag = -1;
137 	}
138 	spin_unlock_irq(&ji->ag_lock);
139 	call_rcu(&inode->i_rcu, jfs_i_callback);
140 }
141 
142 static int jfs_statfs(struct dentry *dentry, struct kstatfs *buf)
143 {
144 	struct jfs_sb_info *sbi = JFS_SBI(dentry->d_sb);
145 	s64 maxinodes;
146 	struct inomap *imap = JFS_IP(sbi->ipimap)->i_imap;
147 
148 	jfs_info("In jfs_statfs");
149 	buf->f_type = JFS_SUPER_MAGIC;
150 	buf->f_bsize = sbi->bsize;
151 	buf->f_blocks = sbi->bmap->db_mapsize;
152 	buf->f_bfree = sbi->bmap->db_nfree;
153 	buf->f_bavail = sbi->bmap->db_nfree;
154 	/*
155 	 * If we really return the number of allocated & free inodes, some
156 	 * applications will fail because they won't see enough free inodes.
157 	 * We'll try to calculate some guess as to how may inodes we can
158 	 * really allocate
159 	 *
160 	 * buf->f_files = atomic_read(&imap->im_numinos);
161 	 * buf->f_ffree = atomic_read(&imap->im_numfree);
162 	 */
163 	maxinodes = min((s64) atomic_read(&imap->im_numinos) +
164 			((sbi->bmap->db_nfree >> imap->im_l2nbperiext)
165 			 << L2INOSPEREXT), (s64) 0xffffffffLL);
166 	buf->f_files = maxinodes;
167 	buf->f_ffree = maxinodes - (atomic_read(&imap->im_numinos) -
168 				    atomic_read(&imap->im_numfree));
169 	buf->f_fsid.val[0] = (u32)crc32_le(0, sbi->uuid, sizeof(sbi->uuid)/2);
170 	buf->f_fsid.val[1] = (u32)crc32_le(0, sbi->uuid + sizeof(sbi->uuid)/2,
171 					sizeof(sbi->uuid)/2);
172 
173 	buf->f_namelen = JFS_NAME_MAX;
174 	return 0;
175 }
176 
177 static void jfs_put_super(struct super_block *sb)
178 {
179 	struct jfs_sb_info *sbi = JFS_SBI(sb);
180 	int rc;
181 
182 	jfs_info("In jfs_put_super");
183 
184 	dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
185 
186 	rc = jfs_umount(sb);
187 	if (rc)
188 		jfs_err("jfs_umount failed with return code %d", rc);
189 
190 	unload_nls(sbi->nls_tab);
191 
192 	truncate_inode_pages(sbi->direct_inode->i_mapping, 0);
193 	iput(sbi->direct_inode);
194 
195 	kfree(sbi);
196 }
197 
198 enum {
199 	Opt_integrity, Opt_nointegrity, Opt_iocharset, Opt_resize,
200 	Opt_resize_nosize, Opt_errors, Opt_ignore, Opt_err, Opt_quota,
201 	Opt_usrquota, Opt_grpquota, Opt_uid, Opt_gid, Opt_umask
202 };
203 
204 static const match_table_t tokens = {
205 	{Opt_integrity, "integrity"},
206 	{Opt_nointegrity, "nointegrity"},
207 	{Opt_iocharset, "iocharset=%s"},
208 	{Opt_resize, "resize=%u"},
209 	{Opt_resize_nosize, "resize"},
210 	{Opt_errors, "errors=%s"},
211 	{Opt_ignore, "noquota"},
212 	{Opt_ignore, "quota"},
213 	{Opt_usrquota, "usrquota"},
214 	{Opt_grpquota, "grpquota"},
215 	{Opt_uid, "uid=%u"},
216 	{Opt_gid, "gid=%u"},
217 	{Opt_umask, "umask=%u"},
218 	{Opt_err, NULL}
219 };
220 
221 static int parse_options(char *options, struct super_block *sb, s64 *newLVSize,
222 			 int *flag)
223 {
224 	void *nls_map = (void *)-1;	/* -1: no change;  NULL: none */
225 	char *p;
226 	struct jfs_sb_info *sbi = JFS_SBI(sb);
227 
228 	*newLVSize = 0;
229 
230 	if (!options)
231 		return 1;
232 
233 	while ((p = strsep(&options, ",")) != NULL) {
234 		substring_t args[MAX_OPT_ARGS];
235 		int token;
236 		if (!*p)
237 			continue;
238 
239 		token = match_token(p, tokens, args);
240 		switch (token) {
241 		case Opt_integrity:
242 			*flag &= ~JFS_NOINTEGRITY;
243 			break;
244 		case Opt_nointegrity:
245 			*flag |= JFS_NOINTEGRITY;
246 			break;
247 		case Opt_ignore:
248 			/* Silently ignore the quota options */
249 			/* Don't do anything ;-) */
250 			break;
251 		case Opt_iocharset:
252 			if (nls_map && nls_map != (void *) -1)
253 				unload_nls(nls_map);
254 			if (!strcmp(args[0].from, "none"))
255 				nls_map = NULL;
256 			else {
257 				nls_map = load_nls(args[0].from);
258 				if (!nls_map) {
259 					printk(KERN_ERR
260 					       "JFS: charset not found\n");
261 					goto cleanup;
262 				}
263 			}
264 			break;
265 		case Opt_resize:
266 		{
267 			char *resize = args[0].from;
268 			*newLVSize = simple_strtoull(resize, &resize, 0);
269 			break;
270 		}
271 		case Opt_resize_nosize:
272 		{
273 			*newLVSize = sb->s_bdev->bd_inode->i_size >>
274 				sb->s_blocksize_bits;
275 			if (*newLVSize == 0)
276 				printk(KERN_ERR
277 				       "JFS: Cannot determine volume size\n");
278 			break;
279 		}
280 		case Opt_errors:
281 		{
282 			char *errors = args[0].from;
283 			if (!errors || !*errors)
284 				goto cleanup;
285 			if (!strcmp(errors, "continue")) {
286 				*flag &= ~JFS_ERR_REMOUNT_RO;
287 				*flag &= ~JFS_ERR_PANIC;
288 				*flag |= JFS_ERR_CONTINUE;
289 			} else if (!strcmp(errors, "remount-ro")) {
290 				*flag &= ~JFS_ERR_CONTINUE;
291 				*flag &= ~JFS_ERR_PANIC;
292 				*flag |= JFS_ERR_REMOUNT_RO;
293 			} else if (!strcmp(errors, "panic")) {
294 				*flag &= ~JFS_ERR_CONTINUE;
295 				*flag &= ~JFS_ERR_REMOUNT_RO;
296 				*flag |= JFS_ERR_PANIC;
297 			} else {
298 				printk(KERN_ERR
299 				       "JFS: %s is an invalid error handler\n",
300 				       errors);
301 				goto cleanup;
302 			}
303 			break;
304 		}
305 
306 #ifdef CONFIG_QUOTA
307 		case Opt_quota:
308 		case Opt_usrquota:
309 			*flag |= JFS_USRQUOTA;
310 			break;
311 		case Opt_grpquota:
312 			*flag |= JFS_GRPQUOTA;
313 			break;
314 #else
315 		case Opt_usrquota:
316 		case Opt_grpquota:
317 		case Opt_quota:
318 			printk(KERN_ERR
319 			       "JFS: quota operations not supported\n");
320 			break;
321 #endif
322 		case Opt_uid:
323 		{
324 			char *uid = args[0].from;
325 			sbi->uid = simple_strtoul(uid, &uid, 0);
326 			break;
327 		}
328 		case Opt_gid:
329 		{
330 			char *gid = args[0].from;
331 			sbi->gid = simple_strtoul(gid, &gid, 0);
332 			break;
333 		}
334 		case Opt_umask:
335 		{
336 			char *umask = args[0].from;
337 			sbi->umask = simple_strtoul(umask, &umask, 8);
338 			if (sbi->umask & ~0777) {
339 				printk(KERN_ERR
340 				       "JFS: Invalid value of umask\n");
341 				goto cleanup;
342 			}
343 			break;
344 		}
345 		default:
346 			printk("jfs: Unrecognized mount option \"%s\" "
347 					" or missing value\n", p);
348 			goto cleanup;
349 		}
350 	}
351 
352 	if (nls_map != (void *) -1) {
353 		/* Discard old (if remount) */
354 		unload_nls(sbi->nls_tab);
355 		sbi->nls_tab = nls_map;
356 	}
357 	return 1;
358 
359 cleanup:
360 	if (nls_map && nls_map != (void *) -1)
361 		unload_nls(nls_map);
362 	return 0;
363 }
364 
365 static int jfs_remount(struct super_block *sb, int *flags, char *data)
366 {
367 	s64 newLVSize = 0;
368 	int rc = 0;
369 	int flag = JFS_SBI(sb)->flag;
370 	int ret;
371 
372 	if (!parse_options(data, sb, &newLVSize, &flag)) {
373 		return -EINVAL;
374 	}
375 
376 	if (newLVSize) {
377 		if (sb->s_flags & MS_RDONLY) {
378 			printk(KERN_ERR
379 		  "JFS: resize requires volume to be mounted read-write\n");
380 			return -EROFS;
381 		}
382 		rc = jfs_extendfs(sb, newLVSize, 0);
383 		if (rc)
384 			return rc;
385 	}
386 
387 	if ((sb->s_flags & MS_RDONLY) && !(*flags & MS_RDONLY)) {
388 		/*
389 		 * Invalidate any previously read metadata.  fsck may have
390 		 * changed the on-disk data since we mounted r/o
391 		 */
392 		truncate_inode_pages(JFS_SBI(sb)->direct_inode->i_mapping, 0);
393 
394 		JFS_SBI(sb)->flag = flag;
395 		ret = jfs_mount_rw(sb, 1);
396 
397 		/* mark the fs r/w for quota activity */
398 		sb->s_flags &= ~MS_RDONLY;
399 
400 		dquot_resume(sb, -1);
401 		return ret;
402 	}
403 	if ((!(sb->s_flags & MS_RDONLY)) && (*flags & MS_RDONLY)) {
404 		rc = dquot_suspend(sb, -1);
405 		if (rc < 0) {
406 			return rc;
407 		}
408 		rc = jfs_umount_rw(sb);
409 		JFS_SBI(sb)->flag = flag;
410 		return rc;
411 	}
412 	if ((JFS_SBI(sb)->flag & JFS_NOINTEGRITY) != (flag & JFS_NOINTEGRITY))
413 		if (!(sb->s_flags & MS_RDONLY)) {
414 			rc = jfs_umount_rw(sb);
415 			if (rc)
416 				return rc;
417 
418 			JFS_SBI(sb)->flag = flag;
419 			ret = jfs_mount_rw(sb, 1);
420 			return ret;
421 		}
422 	JFS_SBI(sb)->flag = flag;
423 
424 	return 0;
425 }
426 
427 static int jfs_fill_super(struct super_block *sb, void *data, int silent)
428 {
429 	struct jfs_sb_info *sbi;
430 	struct inode *inode;
431 	int rc;
432 	s64 newLVSize = 0;
433 	int flag, ret = -EINVAL;
434 
435 	jfs_info("In jfs_read_super: s_flags=0x%lx", sb->s_flags);
436 
437 	if (!new_valid_dev(sb->s_bdev->bd_dev))
438 		return -EOVERFLOW;
439 
440 	sbi = kzalloc(sizeof (struct jfs_sb_info), GFP_KERNEL);
441 	if (!sbi)
442 		return -ENOMEM;
443 
444 	sb->s_fs_info = sbi;
445 	sbi->sb = sb;
446 	sbi->uid = sbi->gid = sbi->umask = -1;
447 
448 	/* initialize the mount flag and determine the default error handler */
449 	flag = JFS_ERR_REMOUNT_RO;
450 
451 	if (!parse_options((char *) data, sb, &newLVSize, &flag))
452 		goto out_kfree;
453 	sbi->flag = flag;
454 
455 #ifdef CONFIG_JFS_POSIX_ACL
456 	sb->s_flags |= MS_POSIXACL;
457 #endif
458 
459 	if (newLVSize) {
460 		printk(KERN_ERR "resize option for remount only\n");
461 		goto out_kfree;
462 	}
463 
464 	/*
465 	 * Initialize blocksize to 4K.
466 	 */
467 	sb_set_blocksize(sb, PSIZE);
468 
469 	/*
470 	 * Set method vectors.
471 	 */
472 	sb->s_op = &jfs_super_operations;
473 	sb->s_export_op = &jfs_export_operations;
474 #ifdef CONFIG_QUOTA
475 	sb->dq_op = &dquot_operations;
476 	sb->s_qcop = &dquot_quotactl_ops;
477 #endif
478 
479 	/*
480 	 * Initialize direct-mapping inode/address-space
481 	 */
482 	inode = new_inode(sb);
483 	if (inode == NULL) {
484 		ret = -ENOMEM;
485 		goto out_unload;
486 	}
487 	inode->i_ino = 0;
488 	inode->i_size = sb->s_bdev->bd_inode->i_size;
489 	inode->i_mapping->a_ops = &jfs_metapage_aops;
490 	insert_inode_hash(inode);
491 	mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
492 
493 	sbi->direct_inode = inode;
494 
495 	rc = jfs_mount(sb);
496 	if (rc) {
497 		if (!silent) {
498 			jfs_err("jfs_mount failed w/return code = %d", rc);
499 		}
500 		goto out_mount_failed;
501 	}
502 	if (sb->s_flags & MS_RDONLY)
503 		sbi->log = NULL;
504 	else {
505 		rc = jfs_mount_rw(sb, 0);
506 		if (rc) {
507 			if (!silent) {
508 				jfs_err("jfs_mount_rw failed, return code = %d",
509 					rc);
510 			}
511 			goto out_no_rw;
512 		}
513 	}
514 
515 	sb->s_magic = JFS_SUPER_MAGIC;
516 
517 	if (sbi->mntflag & JFS_OS2)
518 		sb->s_d_op = &jfs_ci_dentry_operations;
519 
520 	inode = jfs_iget(sb, ROOT_I);
521 	if (IS_ERR(inode)) {
522 		ret = PTR_ERR(inode);
523 		goto out_no_rw;
524 	}
525 	sb->s_root = d_alloc_root(inode);
526 	if (!sb->s_root)
527 		goto out_no_root;
528 
529 	/* logical blocks are represented by 40 bits in pxd_t, etc. */
530 	sb->s_maxbytes = ((u64) sb->s_blocksize) << 40;
531 #if BITS_PER_LONG == 32
532 	/*
533 	 * Page cache is indexed by long.
534 	 * I would use MAX_LFS_FILESIZE, but it's only half as big
535 	 */
536 	sb->s_maxbytes = min(((u64) PAGE_CACHE_SIZE << 32) - 1, (u64)sb->s_maxbytes);
537 #endif
538 	sb->s_time_gran = 1;
539 	return 0;
540 
541 out_no_root:
542 	jfs_err("jfs_read_super: get root dentry failed");
543 	iput(inode);
544 
545 out_no_rw:
546 	rc = jfs_umount(sb);
547 	if (rc) {
548 		jfs_err("jfs_umount failed with return code %d", rc);
549 	}
550 out_mount_failed:
551 	filemap_write_and_wait(sbi->direct_inode->i_mapping);
552 	truncate_inode_pages(sbi->direct_inode->i_mapping, 0);
553 	make_bad_inode(sbi->direct_inode);
554 	iput(sbi->direct_inode);
555 	sbi->direct_inode = NULL;
556 out_unload:
557 	if (sbi->nls_tab)
558 		unload_nls(sbi->nls_tab);
559 out_kfree:
560 	kfree(sbi);
561 	return ret;
562 }
563 
564 static int jfs_freeze(struct super_block *sb)
565 {
566 	struct jfs_sb_info *sbi = JFS_SBI(sb);
567 	struct jfs_log *log = sbi->log;
568 
569 	if (!(sb->s_flags & MS_RDONLY)) {
570 		txQuiesce(sb);
571 		lmLogShutdown(log);
572 		updateSuper(sb, FM_CLEAN);
573 	}
574 	return 0;
575 }
576 
577 static int jfs_unfreeze(struct super_block *sb)
578 {
579 	struct jfs_sb_info *sbi = JFS_SBI(sb);
580 	struct jfs_log *log = sbi->log;
581 	int rc = 0;
582 
583 	if (!(sb->s_flags & MS_RDONLY)) {
584 		updateSuper(sb, FM_MOUNT);
585 		if ((rc = lmLogInit(log)))
586 			jfs_err("jfs_unlock failed with return code %d", rc);
587 		else
588 			txResume(sb);
589 	}
590 	return 0;
591 }
592 
593 static struct dentry *jfs_do_mount(struct file_system_type *fs_type,
594 	int flags, const char *dev_name, void *data)
595 {
596 	return mount_bdev(fs_type, flags, dev_name, data, jfs_fill_super);
597 }
598 
599 static int jfs_sync_fs(struct super_block *sb, int wait)
600 {
601 	struct jfs_log *log = JFS_SBI(sb)->log;
602 
603 	/* log == NULL indicates read-only mount */
604 	if (log) {
605 		jfs_flush_journal(log, wait);
606 		jfs_syncpt(log, 0);
607 	}
608 
609 	return 0;
610 }
611 
612 static int jfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
613 {
614 	struct jfs_sb_info *sbi = JFS_SBI(vfs->mnt_sb);
615 
616 	if (sbi->uid != -1)
617 		seq_printf(seq, ",uid=%d", sbi->uid);
618 	if (sbi->gid != -1)
619 		seq_printf(seq, ",gid=%d", sbi->gid);
620 	if (sbi->umask != -1)
621 		seq_printf(seq, ",umask=%03o", sbi->umask);
622 	if (sbi->flag & JFS_NOINTEGRITY)
623 		seq_puts(seq, ",nointegrity");
624 	if (sbi->nls_tab)
625 		seq_printf(seq, ",iocharset=%s", sbi->nls_tab->charset);
626 	if (sbi->flag & JFS_ERR_CONTINUE)
627 		seq_printf(seq, ",errors=continue");
628 	if (sbi->flag & JFS_ERR_PANIC)
629 		seq_printf(seq, ",errors=panic");
630 
631 #ifdef CONFIG_QUOTA
632 	if (sbi->flag & JFS_USRQUOTA)
633 		seq_puts(seq, ",usrquota");
634 
635 	if (sbi->flag & JFS_GRPQUOTA)
636 		seq_puts(seq, ",grpquota");
637 #endif
638 
639 	return 0;
640 }
641 
642 #ifdef CONFIG_QUOTA
643 
644 /* Read data from quotafile - avoid pagecache and such because we cannot afford
645  * acquiring the locks... As quota files are never truncated and quota code
646  * itself serializes the operations (and no one else should touch the files)
647  * we don't have to be afraid of races */
648 static ssize_t jfs_quota_read(struct super_block *sb, int type, char *data,
649 			      size_t len, loff_t off)
650 {
651 	struct inode *inode = sb_dqopt(sb)->files[type];
652 	sector_t blk = off >> sb->s_blocksize_bits;
653 	int err = 0;
654 	int offset = off & (sb->s_blocksize - 1);
655 	int tocopy;
656 	size_t toread;
657 	struct buffer_head tmp_bh;
658 	struct buffer_head *bh;
659 	loff_t i_size = i_size_read(inode);
660 
661 	if (off > i_size)
662 		return 0;
663 	if (off+len > i_size)
664 		len = i_size-off;
665 	toread = len;
666 	while (toread > 0) {
667 		tocopy = sb->s_blocksize - offset < toread ?
668 				sb->s_blocksize - offset : toread;
669 
670 		tmp_bh.b_state = 0;
671 		tmp_bh.b_size = 1 << inode->i_blkbits;
672 		err = jfs_get_block(inode, blk, &tmp_bh, 0);
673 		if (err)
674 			return err;
675 		if (!buffer_mapped(&tmp_bh))	/* A hole? */
676 			memset(data, 0, tocopy);
677 		else {
678 			bh = sb_bread(sb, tmp_bh.b_blocknr);
679 			if (!bh)
680 				return -EIO;
681 			memcpy(data, bh->b_data+offset, tocopy);
682 			brelse(bh);
683 		}
684 		offset = 0;
685 		toread -= tocopy;
686 		data += tocopy;
687 		blk++;
688 	}
689 	return len;
690 }
691 
692 /* Write to quotafile */
693 static ssize_t jfs_quota_write(struct super_block *sb, int type,
694 			       const char *data, size_t len, loff_t off)
695 {
696 	struct inode *inode = sb_dqopt(sb)->files[type];
697 	sector_t blk = off >> sb->s_blocksize_bits;
698 	int err = 0;
699 	int offset = off & (sb->s_blocksize - 1);
700 	int tocopy;
701 	size_t towrite = len;
702 	struct buffer_head tmp_bh;
703 	struct buffer_head *bh;
704 
705 	mutex_lock(&inode->i_mutex);
706 	while (towrite > 0) {
707 		tocopy = sb->s_blocksize - offset < towrite ?
708 				sb->s_blocksize - offset : towrite;
709 
710 		tmp_bh.b_state = 0;
711 		tmp_bh.b_size = 1 << inode->i_blkbits;
712 		err = jfs_get_block(inode, blk, &tmp_bh, 1);
713 		if (err)
714 			goto out;
715 		if (offset || tocopy != sb->s_blocksize)
716 			bh = sb_bread(sb, tmp_bh.b_blocknr);
717 		else
718 			bh = sb_getblk(sb, tmp_bh.b_blocknr);
719 		if (!bh) {
720 			err = -EIO;
721 			goto out;
722 		}
723 		lock_buffer(bh);
724 		memcpy(bh->b_data+offset, data, tocopy);
725 		flush_dcache_page(bh->b_page);
726 		set_buffer_uptodate(bh);
727 		mark_buffer_dirty(bh);
728 		unlock_buffer(bh);
729 		brelse(bh);
730 		offset = 0;
731 		towrite -= tocopy;
732 		data += tocopy;
733 		blk++;
734 	}
735 out:
736 	if (len == towrite) {
737 		mutex_unlock(&inode->i_mutex);
738 		return err;
739 	}
740 	if (inode->i_size < off+len-towrite)
741 		i_size_write(inode, off+len-towrite);
742 	inode->i_version++;
743 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
744 	mark_inode_dirty(inode);
745 	mutex_unlock(&inode->i_mutex);
746 	return len - towrite;
747 }
748 
749 #endif
750 
751 static const struct super_operations jfs_super_operations = {
752 	.alloc_inode	= jfs_alloc_inode,
753 	.destroy_inode	= jfs_destroy_inode,
754 	.dirty_inode	= jfs_dirty_inode,
755 	.write_inode	= jfs_write_inode,
756 	.evict_inode	= jfs_evict_inode,
757 	.put_super	= jfs_put_super,
758 	.sync_fs	= jfs_sync_fs,
759 	.freeze_fs	= jfs_freeze,
760 	.unfreeze_fs	= jfs_unfreeze,
761 	.statfs		= jfs_statfs,
762 	.remount_fs	= jfs_remount,
763 	.show_options	= jfs_show_options,
764 #ifdef CONFIG_QUOTA
765 	.quota_read	= jfs_quota_read,
766 	.quota_write	= jfs_quota_write,
767 #endif
768 };
769 
770 static const struct export_operations jfs_export_operations = {
771 	.fh_to_dentry	= jfs_fh_to_dentry,
772 	.fh_to_parent	= jfs_fh_to_parent,
773 	.get_parent	= jfs_get_parent,
774 };
775 
776 static struct file_system_type jfs_fs_type = {
777 	.owner		= THIS_MODULE,
778 	.name		= "jfs",
779 	.mount		= jfs_do_mount,
780 	.kill_sb	= kill_block_super,
781 	.fs_flags	= FS_REQUIRES_DEV,
782 };
783 
784 static void init_once(void *foo)
785 {
786 	struct jfs_inode_info *jfs_ip = (struct jfs_inode_info *) foo;
787 
788 	memset(jfs_ip, 0, sizeof(struct jfs_inode_info));
789 	INIT_LIST_HEAD(&jfs_ip->anon_inode_list);
790 	init_rwsem(&jfs_ip->rdwrlock);
791 	mutex_init(&jfs_ip->commit_mutex);
792 	init_rwsem(&jfs_ip->xattr_sem);
793 	spin_lock_init(&jfs_ip->ag_lock);
794 	jfs_ip->active_ag = -1;
795 	inode_init_once(&jfs_ip->vfs_inode);
796 }
797 
798 static int __init init_jfs_fs(void)
799 {
800 	int i;
801 	int rc;
802 
803 	jfs_inode_cachep =
804 	    kmem_cache_create("jfs_ip", sizeof(struct jfs_inode_info), 0,
805 			    SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
806 			    init_once);
807 	if (jfs_inode_cachep == NULL)
808 		return -ENOMEM;
809 
810 	/*
811 	 * Metapage initialization
812 	 */
813 	rc = metapage_init();
814 	if (rc) {
815 		jfs_err("metapage_init failed w/rc = %d", rc);
816 		goto free_slab;
817 	}
818 
819 	/*
820 	 * Transaction Manager initialization
821 	 */
822 	rc = txInit();
823 	if (rc) {
824 		jfs_err("txInit failed w/rc = %d", rc);
825 		goto free_metapage;
826 	}
827 
828 	/*
829 	 * I/O completion thread (endio)
830 	 */
831 	jfsIOthread = kthread_run(jfsIOWait, NULL, "jfsIO");
832 	if (IS_ERR(jfsIOthread)) {
833 		rc = PTR_ERR(jfsIOthread);
834 		jfs_err("init_jfs_fs: fork failed w/rc = %d", rc);
835 		goto end_txmngr;
836 	}
837 
838 	if (commit_threads < 1)
839 		commit_threads = num_online_cpus();
840 	if (commit_threads > MAX_COMMIT_THREADS)
841 		commit_threads = MAX_COMMIT_THREADS;
842 
843 	for (i = 0; i < commit_threads; i++) {
844 		jfsCommitThread[i] = kthread_run(jfs_lazycommit, NULL, "jfsCommit");
845 		if (IS_ERR(jfsCommitThread[i])) {
846 			rc = PTR_ERR(jfsCommitThread[i]);
847 			jfs_err("init_jfs_fs: fork failed w/rc = %d", rc);
848 			commit_threads = i;
849 			goto kill_committask;
850 		}
851 	}
852 
853 	jfsSyncThread = kthread_run(jfs_sync, NULL, "jfsSync");
854 	if (IS_ERR(jfsSyncThread)) {
855 		rc = PTR_ERR(jfsSyncThread);
856 		jfs_err("init_jfs_fs: fork failed w/rc = %d", rc);
857 		goto kill_committask;
858 	}
859 
860 #ifdef PROC_FS_JFS
861 	jfs_proc_init();
862 #endif
863 
864 	return register_filesystem(&jfs_fs_type);
865 
866 kill_committask:
867 	for (i = 0; i < commit_threads; i++)
868 		kthread_stop(jfsCommitThread[i]);
869 	kthread_stop(jfsIOthread);
870 end_txmngr:
871 	txExit();
872 free_metapage:
873 	metapage_exit();
874 free_slab:
875 	kmem_cache_destroy(jfs_inode_cachep);
876 	return rc;
877 }
878 
879 static void __exit exit_jfs_fs(void)
880 {
881 	int i;
882 
883 	jfs_info("exit_jfs_fs called");
884 
885 	txExit();
886 	metapage_exit();
887 
888 	kthread_stop(jfsIOthread);
889 	for (i = 0; i < commit_threads; i++)
890 		kthread_stop(jfsCommitThread[i]);
891 	kthread_stop(jfsSyncThread);
892 #ifdef PROC_FS_JFS
893 	jfs_proc_clean();
894 #endif
895 	unregister_filesystem(&jfs_fs_type);
896 	kmem_cache_destroy(jfs_inode_cachep);
897 }
898 
899 module_init(init_jfs_fs)
900 module_exit(exit_jfs_fs)
901