xref: /linux/fs/befs/linuxvfs.c (revision 827634added7f38b7d724cab1dccdb2b004c13c3)
1 /*
2  * linux/fs/befs/linuxvfs.c
3  *
4  * Copyright (C) 2001 Will Dyson <will_dyson@pobox.com
5  *
6  */
7 
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9 
10 #include <linux/module.h>
11 #include <linux/slab.h>
12 #include <linux/fs.h>
13 #include <linux/errno.h>
14 #include <linux/stat.h>
15 #include <linux/nls.h>
16 #include <linux/buffer_head.h>
17 #include <linux/vfs.h>
18 #include <linux/parser.h>
19 #include <linux/namei.h>
20 #include <linux/sched.h>
21 
22 #include "befs.h"
23 #include "btree.h"
24 #include "inode.h"
25 #include "datastream.h"
26 #include "super.h"
27 #include "io.h"
28 
29 MODULE_DESCRIPTION("BeOS File System (BeFS) driver");
30 MODULE_AUTHOR("Will Dyson");
31 MODULE_LICENSE("GPL");
32 
33 /* The units the vfs expects inode->i_blocks to be in */
34 #define VFS_BLOCK_SIZE 512
35 
36 static int befs_readdir(struct file *, struct dir_context *);
37 static int befs_get_block(struct inode *, sector_t, struct buffer_head *, int);
38 static int befs_readpage(struct file *file, struct page *page);
39 static sector_t befs_bmap(struct address_space *mapping, sector_t block);
40 static struct dentry *befs_lookup(struct inode *, struct dentry *, unsigned int);
41 static struct inode *befs_iget(struct super_block *, unsigned long);
42 static struct inode *befs_alloc_inode(struct super_block *sb);
43 static void befs_destroy_inode(struct inode *inode);
44 static void befs_destroy_inodecache(void);
45 static void *befs_follow_link(struct dentry *, struct nameidata *);
46 static void *befs_fast_follow_link(struct dentry *, struct nameidata *);
47 static int befs_utf2nls(struct super_block *sb, const char *in, int in_len,
48 			char **out, int *out_len);
49 static int befs_nls2utf(struct super_block *sb, const char *in, int in_len,
50 			char **out, int *out_len);
51 static void befs_put_super(struct super_block *);
52 static int befs_remount(struct super_block *, int *, char *);
53 static int befs_statfs(struct dentry *, struct kstatfs *);
54 static int parse_options(char *, struct befs_mount_options *);
55 
56 static const struct super_operations befs_sops = {
57 	.alloc_inode	= befs_alloc_inode,	/* allocate a new inode */
58 	.destroy_inode	= befs_destroy_inode, /* deallocate an inode */
59 	.put_super	= befs_put_super,	/* uninit super */
60 	.statfs		= befs_statfs,	/* statfs */
61 	.remount_fs	= befs_remount,
62 	.show_options	= generic_show_options,
63 };
64 
65 /* slab cache for befs_inode_info objects */
66 static struct kmem_cache *befs_inode_cachep;
67 
68 static const struct file_operations befs_dir_operations = {
69 	.read		= generic_read_dir,
70 	.iterate	= befs_readdir,
71 	.llseek		= generic_file_llseek,
72 };
73 
74 static const struct inode_operations befs_dir_inode_operations = {
75 	.lookup		= befs_lookup,
76 };
77 
78 static const struct address_space_operations befs_aops = {
79 	.readpage	= befs_readpage,
80 	.bmap		= befs_bmap,
81 };
82 
83 static const struct inode_operations befs_fast_symlink_inode_operations = {
84 	.readlink	= generic_readlink,
85 	.follow_link	= befs_fast_follow_link,
86 };
87 
88 static const struct inode_operations befs_symlink_inode_operations = {
89 	.readlink	= generic_readlink,
90 	.follow_link	= befs_follow_link,
91 	.put_link	= kfree_put_link,
92 };
93 
94 /*
95  * Called by generic_file_read() to read a page of data
96  *
97  * In turn, simply calls a generic block read function and
98  * passes it the address of befs_get_block, for mapping file
99  * positions to disk blocks.
100  */
101 static int
102 befs_readpage(struct file *file, struct page *page)
103 {
104 	return block_read_full_page(page, befs_get_block);
105 }
106 
107 static sector_t
108 befs_bmap(struct address_space *mapping, sector_t block)
109 {
110 	return generic_block_bmap(mapping, block, befs_get_block);
111 }
112 
113 /*
114  * Generic function to map a file position (block) to a
115  * disk offset (passed back in bh_result).
116  *
117  * Used by many higher level functions.
118  *
119  * Calls befs_fblock2brun() in datastream.c to do the real work.
120  *
121  * -WD 10-26-01
122  */
123 
124 static int
125 befs_get_block(struct inode *inode, sector_t block,
126 	       struct buffer_head *bh_result, int create)
127 {
128 	struct super_block *sb = inode->i_sb;
129 	befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
130 	befs_block_run run = BAD_IADDR;
131 	int res = 0;
132 	ulong disk_off;
133 
134 	befs_debug(sb, "---> befs_get_block() for inode %lu, block %ld",
135 		   (unsigned long)inode->i_ino, (long)block);
136 	if (create) {
137 		befs_error(sb, "befs_get_block() was asked to write to "
138 			   "block %ld in inode %lu", (long)block,
139 			   (unsigned long)inode->i_ino);
140 		return -EPERM;
141 	}
142 
143 	res = befs_fblock2brun(sb, ds, block, &run);
144 	if (res != BEFS_OK) {
145 		befs_error(sb,
146 			   "<--- %s for inode %lu, block %ld ERROR",
147 			   __func__, (unsigned long)inode->i_ino,
148 			   (long)block);
149 		return -EFBIG;
150 	}
151 
152 	disk_off = (ulong) iaddr2blockno(sb, &run);
153 
154 	map_bh(bh_result, inode->i_sb, disk_off);
155 
156 	befs_debug(sb, "<--- %s for inode %lu, block %ld, disk address %lu",
157 		  __func__, (unsigned long)inode->i_ino, (long)block,
158 		  (unsigned long)disk_off);
159 
160 	return 0;
161 }
162 
163 static struct dentry *
164 befs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
165 {
166 	struct inode *inode = NULL;
167 	struct super_block *sb = dir->i_sb;
168 	befs_data_stream *ds = &BEFS_I(dir)->i_data.ds;
169 	befs_off_t offset;
170 	int ret;
171 	int utfnamelen;
172 	char *utfname;
173 	const char *name = dentry->d_name.name;
174 
175 	befs_debug(sb, "---> %s name %pd inode %ld", __func__,
176 		   dentry, dir->i_ino);
177 
178 	/* Convert to UTF-8 */
179 	if (BEFS_SB(sb)->nls) {
180 		ret =
181 		    befs_nls2utf(sb, name, strlen(name), &utfname, &utfnamelen);
182 		if (ret < 0) {
183 			befs_debug(sb, "<--- %s ERROR", __func__);
184 			return ERR_PTR(ret);
185 		}
186 		ret = befs_btree_find(sb, ds, utfname, &offset);
187 		kfree(utfname);
188 
189 	} else {
190 		ret = befs_btree_find(sb, ds, dentry->d_name.name, &offset);
191 	}
192 
193 	if (ret == BEFS_BT_NOT_FOUND) {
194 		befs_debug(sb, "<--- %s %pd not found", __func__, dentry);
195 		return ERR_PTR(-ENOENT);
196 
197 	} else if (ret != BEFS_OK || offset == 0) {
198 		befs_warning(sb, "<--- %s Error", __func__);
199 		return ERR_PTR(-ENODATA);
200 	}
201 
202 	inode = befs_iget(dir->i_sb, (ino_t) offset);
203 	if (IS_ERR(inode))
204 		return ERR_CAST(inode);
205 
206 	d_add(dentry, inode);
207 
208 	befs_debug(sb, "<--- %s", __func__);
209 
210 	return NULL;
211 }
212 
213 static int
214 befs_readdir(struct file *file, struct dir_context *ctx)
215 {
216 	struct inode *inode = file_inode(file);
217 	struct super_block *sb = inode->i_sb;
218 	befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
219 	befs_off_t value;
220 	int result;
221 	size_t keysize;
222 	unsigned char d_type;
223 	char keybuf[BEFS_NAME_LEN + 1];
224 
225 	befs_debug(sb, "---> %s name %pD, inode %ld, ctx->pos %lld",
226 		  __func__, file, inode->i_ino, ctx->pos);
227 
228 more:
229 	result = befs_btree_read(sb, ds, ctx->pos, BEFS_NAME_LEN + 1,
230 				 keybuf, &keysize, &value);
231 
232 	if (result == BEFS_ERR) {
233 		befs_debug(sb, "<--- %s ERROR", __func__);
234 		befs_error(sb, "IO error reading %pD (inode %lu)",
235 			   file, inode->i_ino);
236 		return -EIO;
237 
238 	} else if (result == BEFS_BT_END) {
239 		befs_debug(sb, "<--- %s END", __func__);
240 		return 0;
241 
242 	} else if (result == BEFS_BT_EMPTY) {
243 		befs_debug(sb, "<--- %s Empty directory", __func__);
244 		return 0;
245 	}
246 
247 	d_type = DT_UNKNOWN;
248 
249 	/* Convert to NLS */
250 	if (BEFS_SB(sb)->nls) {
251 		char *nlsname;
252 		int nlsnamelen;
253 		result =
254 		    befs_utf2nls(sb, keybuf, keysize, &nlsname, &nlsnamelen);
255 		if (result < 0) {
256 			befs_debug(sb, "<--- %s ERROR", __func__);
257 			return result;
258 		}
259 		if (!dir_emit(ctx, nlsname, nlsnamelen,
260 				 (ino_t) value, d_type)) {
261 			kfree(nlsname);
262 			return 0;
263 		}
264 		kfree(nlsname);
265 	} else {
266 		if (!dir_emit(ctx, keybuf, keysize,
267 				 (ino_t) value, d_type))
268 			return 0;
269 	}
270 	ctx->pos++;
271 	goto more;
272 }
273 
274 static struct inode *
275 befs_alloc_inode(struct super_block *sb)
276 {
277 	struct befs_inode_info *bi;
278 
279 	bi = kmem_cache_alloc(befs_inode_cachep, GFP_KERNEL);
280         if (!bi)
281                 return NULL;
282         return &bi->vfs_inode;
283 }
284 
285 static void befs_i_callback(struct rcu_head *head)
286 {
287 	struct inode *inode = container_of(head, struct inode, i_rcu);
288         kmem_cache_free(befs_inode_cachep, BEFS_I(inode));
289 }
290 
291 static void befs_destroy_inode(struct inode *inode)
292 {
293 	call_rcu(&inode->i_rcu, befs_i_callback);
294 }
295 
296 static void init_once(void *foo)
297 {
298         struct befs_inode_info *bi = (struct befs_inode_info *) foo;
299 
300 	inode_init_once(&bi->vfs_inode);
301 }
302 
303 static struct inode *befs_iget(struct super_block *sb, unsigned long ino)
304 {
305 	struct buffer_head *bh = NULL;
306 	befs_inode *raw_inode = NULL;
307 	struct befs_sb_info *befs_sb = BEFS_SB(sb);
308 	struct befs_inode_info *befs_ino = NULL;
309 	struct inode *inode;
310 	long ret = -EIO;
311 
312 	befs_debug(sb, "---> %s inode = %lu", __func__, ino);
313 
314 	inode = iget_locked(sb, ino);
315 	if (!inode)
316 		return ERR_PTR(-ENOMEM);
317 	if (!(inode->i_state & I_NEW))
318 		return inode;
319 
320 	befs_ino = BEFS_I(inode);
321 
322 	/* convert from vfs's inode number to befs's inode number */
323 	befs_ino->i_inode_num = blockno2iaddr(sb, inode->i_ino);
324 
325 	befs_debug(sb, "  real inode number [%u, %hu, %hu]",
326 		   befs_ino->i_inode_num.allocation_group,
327 		   befs_ino->i_inode_num.start, befs_ino->i_inode_num.len);
328 
329 	bh = befs_bread(sb, inode->i_ino);
330 	if (!bh) {
331 		befs_error(sb, "unable to read inode block - "
332 			   "inode = %lu", inode->i_ino);
333 		goto unacquire_none;
334 	}
335 
336 	raw_inode = (befs_inode *) bh->b_data;
337 
338 	befs_dump_inode(sb, raw_inode);
339 
340 	if (befs_check_inode(sb, raw_inode, inode->i_ino) != BEFS_OK) {
341 		befs_error(sb, "Bad inode: %lu", inode->i_ino);
342 		goto unacquire_bh;
343 	}
344 
345 	inode->i_mode = (umode_t) fs32_to_cpu(sb, raw_inode->mode);
346 
347 	/*
348 	 * set uid and gid.  But since current BeOS is single user OS, so
349 	 * you can change by "uid" or "gid" options.
350 	 */
351 
352 	inode->i_uid = befs_sb->mount_opts.use_uid ?
353 		befs_sb->mount_opts.uid :
354 		make_kuid(&init_user_ns, fs32_to_cpu(sb, raw_inode->uid));
355 	inode->i_gid = befs_sb->mount_opts.use_gid ?
356 		befs_sb->mount_opts.gid :
357 		make_kgid(&init_user_ns, fs32_to_cpu(sb, raw_inode->gid));
358 
359 	set_nlink(inode, 1);
360 
361 	/*
362 	 * BEFS's time is 64 bits, but current VFS is 32 bits...
363 	 * BEFS don't have access time. Nor inode change time. VFS
364 	 * doesn't have creation time.
365 	 * Also, the lower 16 bits of the last_modified_time and
366 	 * create_time are just a counter to help ensure uniqueness
367 	 * for indexing purposes. (PFD, page 54)
368 	 */
369 
370 	inode->i_mtime.tv_sec =
371 	    fs64_to_cpu(sb, raw_inode->last_modified_time) >> 16;
372 	inode->i_mtime.tv_nsec = 0;   /* lower 16 bits are not a time */
373 	inode->i_ctime = inode->i_mtime;
374 	inode->i_atime = inode->i_mtime;
375 
376 	befs_ino->i_inode_num = fsrun_to_cpu(sb, raw_inode->inode_num);
377 	befs_ino->i_parent = fsrun_to_cpu(sb, raw_inode->parent);
378 	befs_ino->i_attribute = fsrun_to_cpu(sb, raw_inode->attributes);
379 	befs_ino->i_flags = fs32_to_cpu(sb, raw_inode->flags);
380 
381 	if (S_ISLNK(inode->i_mode) && !(befs_ino->i_flags & BEFS_LONG_SYMLINK)){
382 		inode->i_size = 0;
383 		inode->i_blocks = befs_sb->block_size / VFS_BLOCK_SIZE;
384 		strlcpy(befs_ino->i_data.symlink, raw_inode->data.symlink,
385 			BEFS_SYMLINK_LEN);
386 	} else {
387 		int num_blks;
388 
389 		befs_ino->i_data.ds =
390 		    fsds_to_cpu(sb, &raw_inode->data.datastream);
391 
392 		num_blks = befs_count_blocks(sb, &befs_ino->i_data.ds);
393 		inode->i_blocks =
394 		    num_blks * (befs_sb->block_size / VFS_BLOCK_SIZE);
395 		inode->i_size = befs_ino->i_data.ds.size;
396 	}
397 
398 	inode->i_mapping->a_ops = &befs_aops;
399 
400 	if (S_ISREG(inode->i_mode)) {
401 		inode->i_fop = &generic_ro_fops;
402 	} else if (S_ISDIR(inode->i_mode)) {
403 		inode->i_op = &befs_dir_inode_operations;
404 		inode->i_fop = &befs_dir_operations;
405 	} else if (S_ISLNK(inode->i_mode)) {
406 		if (befs_ino->i_flags & BEFS_LONG_SYMLINK)
407 			inode->i_op = &befs_symlink_inode_operations;
408 		else
409 			inode->i_op = &befs_fast_symlink_inode_operations;
410 	} else {
411 		befs_error(sb, "Inode %lu is not a regular file, "
412 			   "directory or symlink. THAT IS WRONG! BeFS has no "
413 			   "on disk special files", inode->i_ino);
414 		goto unacquire_bh;
415 	}
416 
417 	brelse(bh);
418 	befs_debug(sb, "<--- %s", __func__);
419 	unlock_new_inode(inode);
420 	return inode;
421 
422       unacquire_bh:
423 	brelse(bh);
424 
425       unacquire_none:
426 	iget_failed(inode);
427 	befs_debug(sb, "<--- %s - Bad inode", __func__);
428 	return ERR_PTR(ret);
429 }
430 
431 /* Initialize the inode cache. Called at fs setup.
432  *
433  * Taken from NFS implementation by Al Viro.
434  */
435 static int __init
436 befs_init_inodecache(void)
437 {
438 	befs_inode_cachep = kmem_cache_create("befs_inode_cache",
439 					      sizeof (struct befs_inode_info),
440 					      0, (SLAB_RECLAIM_ACCOUNT|
441 						SLAB_MEM_SPREAD),
442 					      init_once);
443 	if (befs_inode_cachep == NULL) {
444 		pr_err("%s: Couldn't initialize inode slabcache\n", __func__);
445 		return -ENOMEM;
446 	}
447 	return 0;
448 }
449 
450 /* Called at fs teardown.
451  *
452  * Taken from NFS implementation by Al Viro.
453  */
454 static void
455 befs_destroy_inodecache(void)
456 {
457 	/*
458 	 * Make sure all delayed rcu free inodes are flushed before we
459 	 * destroy cache.
460 	 */
461 	rcu_barrier();
462 	kmem_cache_destroy(befs_inode_cachep);
463 }
464 
465 /*
466  * The inode of symbolic link is different to data stream.
467  * The data stream become link name. Unless the LONG_SYMLINK
468  * flag is set.
469  */
470 static void *
471 befs_follow_link(struct dentry *dentry, struct nameidata *nd)
472 {
473 	struct super_block *sb = dentry->d_sb;
474 	struct befs_inode_info *befs_ino = BEFS_I(d_inode(dentry));
475 	befs_data_stream *data = &befs_ino->i_data.ds;
476 	befs_off_t len = data->size;
477 	char *link;
478 
479 	if (len == 0) {
480 		befs_error(sb, "Long symlink with illegal length");
481 		link = ERR_PTR(-EIO);
482 	} else {
483 		befs_debug(sb, "Follow long symlink");
484 
485 		link = kmalloc(len, GFP_NOFS);
486 		if (!link) {
487 			link = ERR_PTR(-ENOMEM);
488 		} else if (befs_read_lsymlink(sb, data, link, len) != len) {
489 			kfree(link);
490 			befs_error(sb, "Failed to read entire long symlink");
491 			link = ERR_PTR(-EIO);
492 		} else {
493 			link[len - 1] = '\0';
494 		}
495 	}
496 	nd_set_link(nd, link);
497 	return NULL;
498 }
499 
500 
501 static void *
502 befs_fast_follow_link(struct dentry *dentry, struct nameidata *nd)
503 {
504 	struct befs_inode_info *befs_ino = BEFS_I(d_inode(dentry));
505 
506 	nd_set_link(nd, befs_ino->i_data.symlink);
507 	return NULL;
508 }
509 
510 /*
511  * UTF-8 to NLS charset  convert routine
512  *
513  *
514  * Changed 8/10/01 by Will Dyson. Now use uni2char() / char2uni() rather than
515  * the nls tables directly
516  */
517 
518 static int
519 befs_utf2nls(struct super_block *sb, const char *in,
520 	     int in_len, char **out, int *out_len)
521 {
522 	struct nls_table *nls = BEFS_SB(sb)->nls;
523 	int i, o;
524 	unicode_t uni;
525 	int unilen, utflen;
526 	char *result;
527 	/* The utf8->nls conversion won't make the final nls string bigger
528 	 * than the utf one, but if the string is pure ascii they'll have the
529 	 * same width and an extra char is needed to save the additional \0
530 	 */
531 	int maxlen = in_len + 1;
532 
533 	befs_debug(sb, "---> %s", __func__);
534 
535 	if (!nls) {
536 		befs_error(sb, "%s called with no NLS table loaded", __func__);
537 		return -EINVAL;
538 	}
539 
540 	*out = result = kmalloc(maxlen, GFP_NOFS);
541 	if (!*out) {
542 		befs_error(sb, "%s cannot allocate memory", __func__);
543 		*out_len = 0;
544 		return -ENOMEM;
545 	}
546 
547 	for (i = o = 0; i < in_len; i += utflen, o += unilen) {
548 
549 		/* convert from UTF-8 to Unicode */
550 		utflen = utf8_to_utf32(&in[i], in_len - i, &uni);
551 		if (utflen < 0)
552 			goto conv_err;
553 
554 		/* convert from Unicode to nls */
555 		if (uni > MAX_WCHAR_T)
556 			goto conv_err;
557 		unilen = nls->uni2char(uni, &result[o], in_len - o);
558 		if (unilen < 0)
559 			goto conv_err;
560 	}
561 	result[o] = '\0';
562 	*out_len = o;
563 
564 	befs_debug(sb, "<--- %s", __func__);
565 
566 	return o;
567 
568       conv_err:
569 	befs_error(sb, "Name using character set %s contains a character that "
570 		   "cannot be converted to unicode.", nls->charset);
571 	befs_debug(sb, "<--- %s", __func__);
572 	kfree(result);
573 	return -EILSEQ;
574 }
575 
576 /**
577  * befs_nls2utf - Convert NLS string to utf8 encodeing
578  * @sb: Superblock
579  * @in: Input string buffer in NLS format
580  * @in_len: Length of input string in bytes
581  * @out: The output string in UTF-8 format
582  * @out_len: Length of the output buffer
583  *
584  * Converts input string @in, which is in the format of the loaded NLS map,
585  * into a utf8 string.
586  *
587  * The destination string @out is allocated by this function and the caller is
588  * responsible for freeing it with kfree()
589  *
590  * On return, *@out_len is the length of @out in bytes.
591  *
592  * On success, the return value is the number of utf8 characters written to
593  * the output buffer @out.
594  *
595  * On Failure, a negative number coresponding to the error code is returned.
596  */
597 
598 static int
599 befs_nls2utf(struct super_block *sb, const char *in,
600 	     int in_len, char **out, int *out_len)
601 {
602 	struct nls_table *nls = BEFS_SB(sb)->nls;
603 	int i, o;
604 	wchar_t uni;
605 	int unilen, utflen;
606 	char *result;
607 	/* There're nls characters that will translate to 3-chars-wide UTF-8
608 	 * characters, a additional byte is needed to save the final \0
609 	 * in special cases */
610 	int maxlen = (3 * in_len) + 1;
611 
612 	befs_debug(sb, "---> %s\n", __func__);
613 
614 	if (!nls) {
615 		befs_error(sb, "%s called with no NLS table loaded.",
616 			   __func__);
617 		return -EINVAL;
618 	}
619 
620 	*out = result = kmalloc(maxlen, GFP_NOFS);
621 	if (!*out) {
622 		befs_error(sb, "%s cannot allocate memory", __func__);
623 		*out_len = 0;
624 		return -ENOMEM;
625 	}
626 
627 	for (i = o = 0; i < in_len; i += unilen, o += utflen) {
628 
629 		/* convert from nls to unicode */
630 		unilen = nls->char2uni(&in[i], in_len - i, &uni);
631 		if (unilen < 0)
632 			goto conv_err;
633 
634 		/* convert from unicode to UTF-8 */
635 		utflen = utf32_to_utf8(uni, &result[o], 3);
636 		if (utflen <= 0)
637 			goto conv_err;
638 	}
639 
640 	result[o] = '\0';
641 	*out_len = o;
642 
643 	befs_debug(sb, "<--- %s", __func__);
644 
645 	return i;
646 
647       conv_err:
648 	befs_error(sb, "Name using charecter set %s contains a charecter that "
649 		   "cannot be converted to unicode.", nls->charset);
650 	befs_debug(sb, "<--- %s", __func__);
651 	kfree(result);
652 	return -EILSEQ;
653 }
654 
655 /**
656  * Use the
657  *
658  */
659 enum {
660 	Opt_uid, Opt_gid, Opt_charset, Opt_debug, Opt_err,
661 };
662 
663 static const match_table_t befs_tokens = {
664 	{Opt_uid, "uid=%d"},
665 	{Opt_gid, "gid=%d"},
666 	{Opt_charset, "iocharset=%s"},
667 	{Opt_debug, "debug"},
668 	{Opt_err, NULL}
669 };
670 
671 static int
672 parse_options(char *options, struct befs_mount_options *opts)
673 {
674 	char *p;
675 	substring_t args[MAX_OPT_ARGS];
676 	int option;
677 	kuid_t uid;
678 	kgid_t gid;
679 
680 	/* Initialize options */
681 	opts->uid = GLOBAL_ROOT_UID;
682 	opts->gid = GLOBAL_ROOT_GID;
683 	opts->use_uid = 0;
684 	opts->use_gid = 0;
685 	opts->iocharset = NULL;
686 	opts->debug = 0;
687 
688 	if (!options)
689 		return 1;
690 
691 	while ((p = strsep(&options, ",")) != NULL) {
692 		int token;
693 		if (!*p)
694 			continue;
695 
696 		token = match_token(p, befs_tokens, args);
697 		switch (token) {
698 		case Opt_uid:
699 			if (match_int(&args[0], &option))
700 				return 0;
701 			uid = INVALID_UID;
702 			if (option >= 0)
703 				uid = make_kuid(current_user_ns(), option);
704 			if (!uid_valid(uid)) {
705 				pr_err("Invalid uid %d, "
706 				       "using default\n", option);
707 				break;
708 			}
709 			opts->uid = uid;
710 			opts->use_uid = 1;
711 			break;
712 		case Opt_gid:
713 			if (match_int(&args[0], &option))
714 				return 0;
715 			gid = INVALID_GID;
716 			if (option >= 0)
717 				gid = make_kgid(current_user_ns(), option);
718 			if (!gid_valid(gid)) {
719 				pr_err("Invalid gid %d, "
720 				       "using default\n", option);
721 				break;
722 			}
723 			opts->gid = gid;
724 			opts->use_gid = 1;
725 			break;
726 		case Opt_charset:
727 			kfree(opts->iocharset);
728 			opts->iocharset = match_strdup(&args[0]);
729 			if (!opts->iocharset) {
730 				pr_err("allocation failure for "
731 				       "iocharset string\n");
732 				return 0;
733 			}
734 			break;
735 		case Opt_debug:
736 			opts->debug = 1;
737 			break;
738 		default:
739 			pr_err("Unrecognized mount option \"%s\" "
740 			       "or missing value\n", p);
741 			return 0;
742 		}
743 	}
744 	return 1;
745 }
746 
747 /* This function has the responsibiltiy of getting the
748  * filesystem ready for unmounting.
749  * Basically, we free everything that we allocated in
750  * befs_read_inode
751  */
752 static void
753 befs_put_super(struct super_block *sb)
754 {
755 	kfree(BEFS_SB(sb)->mount_opts.iocharset);
756 	BEFS_SB(sb)->mount_opts.iocharset = NULL;
757 	unload_nls(BEFS_SB(sb)->nls);
758 	kfree(sb->s_fs_info);
759 	sb->s_fs_info = NULL;
760 }
761 
762 /* Allocate private field of the superblock, fill it.
763  *
764  * Finish filling the public superblock fields
765  * Make the root directory
766  * Load a set of NLS translations if needed.
767  */
768 static int
769 befs_fill_super(struct super_block *sb, void *data, int silent)
770 {
771 	struct buffer_head *bh;
772 	struct befs_sb_info *befs_sb;
773 	befs_super_block *disk_sb;
774 	struct inode *root;
775 	long ret = -EINVAL;
776 	const unsigned long sb_block = 0;
777 	const off_t x86_sb_off = 512;
778 
779 	save_mount_options(sb, data);
780 
781 	sb->s_fs_info = kzalloc(sizeof(*befs_sb), GFP_KERNEL);
782 	if (sb->s_fs_info == NULL) {
783 		pr_err("(%s): Unable to allocate memory for private "
784 		       "portion of superblock. Bailing.\n", sb->s_id);
785 		goto unacquire_none;
786 	}
787 	befs_sb = BEFS_SB(sb);
788 
789 	if (!parse_options((char *) data, &befs_sb->mount_opts)) {
790 		befs_error(sb, "cannot parse mount options");
791 		goto unacquire_priv_sbp;
792 	}
793 
794 	befs_debug(sb, "---> %s", __func__);
795 
796 	if (!(sb->s_flags & MS_RDONLY)) {
797 		befs_warning(sb,
798 			     "No write support. Marking filesystem read-only");
799 		sb->s_flags |= MS_RDONLY;
800 	}
801 
802 	/*
803 	 * Set dummy blocksize to read super block.
804 	 * Will be set to real fs blocksize later.
805 	 *
806 	 * Linux 2.4.10 and later refuse to read blocks smaller than
807 	 * the hardsect size for the device. But we also need to read at
808 	 * least 1k to get the second 512 bytes of the volume.
809 	 * -WD 10-26-01
810 	 */
811 	sb_min_blocksize(sb, 1024);
812 
813 	if (!(bh = sb_bread(sb, sb_block))) {
814 		befs_error(sb, "unable to read superblock");
815 		goto unacquire_priv_sbp;
816 	}
817 
818 	/* account for offset of super block on x86 */
819 	disk_sb = (befs_super_block *) bh->b_data;
820 	if ((disk_sb->magic1 == BEFS_SUPER_MAGIC1_LE) ||
821 	    (disk_sb->magic1 == BEFS_SUPER_MAGIC1_BE)) {
822 		befs_debug(sb, "Using PPC superblock location");
823 	} else {
824 		befs_debug(sb, "Using x86 superblock location");
825 		disk_sb =
826 		    (befs_super_block *) ((void *) bh->b_data + x86_sb_off);
827 	}
828 
829 	if ((befs_load_sb(sb, disk_sb) != BEFS_OK) ||
830 	    (befs_check_sb(sb) != BEFS_OK))
831 		goto unacquire_bh;
832 
833 	befs_dump_super_block(sb, disk_sb);
834 
835 	brelse(bh);
836 
837 	if( befs_sb->num_blocks > ~((sector_t)0) ) {
838 		befs_error(sb, "blocks count: %llu "
839 			"is larger than the host can use",
840 			befs_sb->num_blocks);
841 		goto unacquire_priv_sbp;
842 	}
843 
844 	/*
845 	 * set up enough so that it can read an inode
846 	 * Fill in kernel superblock fields from private sb
847 	 */
848 	sb->s_magic = BEFS_SUPER_MAGIC;
849 	/* Set real blocksize of fs */
850 	sb_set_blocksize(sb, (ulong) befs_sb->block_size);
851 	sb->s_op = &befs_sops;
852 	root = befs_iget(sb, iaddr2blockno(sb, &(befs_sb->root_dir)));
853 	if (IS_ERR(root)) {
854 		ret = PTR_ERR(root);
855 		goto unacquire_priv_sbp;
856 	}
857 	sb->s_root = d_make_root(root);
858 	if (!sb->s_root) {
859 		befs_error(sb, "get root inode failed");
860 		goto unacquire_priv_sbp;
861 	}
862 
863 	/* load nls library */
864 	if (befs_sb->mount_opts.iocharset) {
865 		befs_debug(sb, "Loading nls: %s",
866 			   befs_sb->mount_opts.iocharset);
867 		befs_sb->nls = load_nls(befs_sb->mount_opts.iocharset);
868 		if (!befs_sb->nls) {
869 			befs_warning(sb, "Cannot load nls %s"
870 					" loading default nls",
871 					befs_sb->mount_opts.iocharset);
872 			befs_sb->nls = load_nls_default();
873 		}
874 	/* load default nls if none is specified  in mount options */
875 	} else {
876 		befs_debug(sb, "Loading default nls");
877 		befs_sb->nls = load_nls_default();
878 	}
879 
880 	return 0;
881 /*****************/
882       unacquire_bh:
883 	brelse(bh);
884 
885       unacquire_priv_sbp:
886 	kfree(befs_sb->mount_opts.iocharset);
887 	kfree(sb->s_fs_info);
888 
889       unacquire_none:
890 	sb->s_fs_info = NULL;
891 	return ret;
892 }
893 
894 static int
895 befs_remount(struct super_block *sb, int *flags, char *data)
896 {
897 	sync_filesystem(sb);
898 	if (!(*flags & MS_RDONLY))
899 		return -EINVAL;
900 	return 0;
901 }
902 
903 static int
904 befs_statfs(struct dentry *dentry, struct kstatfs *buf)
905 {
906 	struct super_block *sb = dentry->d_sb;
907 	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
908 
909 	befs_debug(sb, "---> %s", __func__);
910 
911 	buf->f_type = BEFS_SUPER_MAGIC;
912 	buf->f_bsize = sb->s_blocksize;
913 	buf->f_blocks = BEFS_SB(sb)->num_blocks;
914 	buf->f_bfree = BEFS_SB(sb)->num_blocks - BEFS_SB(sb)->used_blocks;
915 	buf->f_bavail = buf->f_bfree;
916 	buf->f_files = 0;	/* UNKNOWN */
917 	buf->f_ffree = 0;	/* UNKNOWN */
918 	buf->f_fsid.val[0] = (u32)id;
919 	buf->f_fsid.val[1] = (u32)(id >> 32);
920 	buf->f_namelen = BEFS_NAME_LEN;
921 
922 	befs_debug(sb, "<--- %s", __func__);
923 
924 	return 0;
925 }
926 
927 static struct dentry *
928 befs_mount(struct file_system_type *fs_type, int flags, const char *dev_name,
929 	    void *data)
930 {
931 	return mount_bdev(fs_type, flags, dev_name, data, befs_fill_super);
932 }
933 
934 static struct file_system_type befs_fs_type = {
935 	.owner		= THIS_MODULE,
936 	.name		= "befs",
937 	.mount		= befs_mount,
938 	.kill_sb	= kill_block_super,
939 	.fs_flags	= FS_REQUIRES_DEV,
940 };
941 MODULE_ALIAS_FS("befs");
942 
943 static int __init
944 init_befs_fs(void)
945 {
946 	int err;
947 
948 	pr_info("version: %s\n", BEFS_VERSION);
949 
950 	err = befs_init_inodecache();
951 	if (err)
952 		goto unacquire_none;
953 
954 	err = register_filesystem(&befs_fs_type);
955 	if (err)
956 		goto unacquire_inodecache;
957 
958 	return 0;
959 
960 unacquire_inodecache:
961 	befs_destroy_inodecache();
962 
963 unacquire_none:
964 	return err;
965 }
966 
967 static void __exit
968 exit_befs_fs(void)
969 {
970 	befs_destroy_inodecache();
971 
972 	unregister_filesystem(&befs_fs_type);
973 }
974 
975 /*
976 Macros that typecheck the init and exit functions,
977 ensures that they are called at init and cleanup,
978 and eliminates warnings about unused functions.
979 */
980 module_init(init_befs_fs)
981 module_exit(exit_befs_fs)
982