xref: /openbmc/linux/fs/befs/linuxvfs.c (revision ae3473231e77a3f1909d48cd144cebe5e1d049b3)
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 #include <linux/exportfs.h>
22 
23 #include "befs.h"
24 #include "btree.h"
25 #include "inode.h"
26 #include "datastream.h"
27 #include "super.h"
28 #include "io.h"
29 
30 MODULE_DESCRIPTION("BeOS File System (BeFS) driver");
31 MODULE_AUTHOR("Will Dyson");
32 MODULE_LICENSE("GPL");
33 
34 /* The units the vfs expects inode->i_blocks to be in */
35 #define VFS_BLOCK_SIZE 512
36 
37 static int befs_readdir(struct file *, struct dir_context *);
38 static int befs_get_block(struct inode *, sector_t, struct buffer_head *, int);
39 static int befs_readpage(struct file *file, struct page *page);
40 static sector_t befs_bmap(struct address_space *mapping, sector_t block);
41 static struct dentry *befs_lookup(struct inode *, struct dentry *,
42 				  unsigned int);
43 static struct inode *befs_iget(struct super_block *, unsigned long);
44 static struct inode *befs_alloc_inode(struct super_block *sb);
45 static void befs_destroy_inode(struct inode *inode);
46 static void befs_destroy_inodecache(void);
47 static int befs_symlink_readpage(struct file *, struct page *);
48 static int befs_utf2nls(struct super_block *sb, const char *in, int in_len,
49 			char **out, int *out_len);
50 static int befs_nls2utf(struct super_block *sb, const char *in, int in_len,
51 			char **out, int *out_len);
52 static void befs_put_super(struct super_block *);
53 static int befs_remount(struct super_block *, int *, char *);
54 static int befs_statfs(struct dentry *, struct kstatfs *);
55 static int parse_options(char *, struct befs_mount_options *);
56 static struct dentry *befs_fh_to_dentry(struct super_block *sb,
57 				struct fid *fid, int fh_len, int fh_type);
58 static struct dentry *befs_fh_to_parent(struct super_block *sb,
59 				struct fid *fid, int fh_len, int fh_type);
60 
61 static const struct super_operations befs_sops = {
62 	.alloc_inode	= befs_alloc_inode,	/* allocate a new inode */
63 	.destroy_inode	= befs_destroy_inode, /* deallocate an inode */
64 	.put_super	= befs_put_super,	/* uninit super */
65 	.statfs		= befs_statfs,	/* statfs */
66 	.remount_fs	= befs_remount,
67 	.show_options	= generic_show_options,
68 };
69 
70 /* slab cache for befs_inode_info objects */
71 static struct kmem_cache *befs_inode_cachep;
72 
73 static const struct file_operations befs_dir_operations = {
74 	.read		= generic_read_dir,
75 	.iterate_shared	= befs_readdir,
76 	.llseek		= generic_file_llseek,
77 };
78 
79 static const struct inode_operations befs_dir_inode_operations = {
80 	.lookup		= befs_lookup,
81 };
82 
83 static const struct address_space_operations befs_aops = {
84 	.readpage	= befs_readpage,
85 	.bmap		= befs_bmap,
86 };
87 
88 static const struct address_space_operations befs_symlink_aops = {
89 	.readpage	= befs_symlink_readpage,
90 };
91 
92 static const struct export_operations befs_export_operations = {
93 	.fh_to_dentry	= befs_fh_to_dentry,
94 	.fh_to_parent	= befs_fh_to_parent,
95 };
96 
97 /*
98  * Called by generic_file_read() to read a page of data
99  *
100  * In turn, simply calls a generic block read function and
101  * passes it the address of befs_get_block, for mapping file
102  * positions to disk blocks.
103  */
104 static int
105 befs_readpage(struct file *file, struct page *page)
106 {
107 	return block_read_full_page(page, befs_get_block);
108 }
109 
110 static sector_t
111 befs_bmap(struct address_space *mapping, sector_t block)
112 {
113 	return generic_block_bmap(mapping, block, befs_get_block);
114 }
115 
116 /*
117  * Generic function to map a file position (block) to a
118  * disk offset (passed back in bh_result).
119  *
120  * Used by many higher level functions.
121  *
122  * Calls befs_fblock2brun() in datastream.c to do the real work.
123  */
124 
125 static int
126 befs_get_block(struct inode *inode, sector_t block,
127 	       struct buffer_head *bh_result, int create)
128 {
129 	struct super_block *sb = inode->i_sb;
130 	befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
131 	befs_block_run run = BAD_IADDR;
132 	int res;
133 	ulong disk_off;
134 
135 	befs_debug(sb, "---> befs_get_block() for inode %lu, block %ld",
136 		   (unsigned long)inode->i_ino, (long)block);
137 	if (create) {
138 		befs_error(sb, "befs_get_block() was asked to write to "
139 			   "block %ld in inode %lu", (long)block,
140 			   (unsigned long)inode->i_ino);
141 		return -EPERM;
142 	}
143 
144 	res = befs_fblock2brun(sb, ds, block, &run);
145 	if (res != BEFS_OK) {
146 		befs_error(sb,
147 			   "<--- %s for inode %lu, block %ld ERROR",
148 			   __func__, (unsigned long)inode->i_ino,
149 			   (long)block);
150 		return -EFBIG;
151 	}
152 
153 	disk_off = (ulong) iaddr2blockno(sb, &run);
154 
155 	map_bh(bh_result, inode->i_sb, disk_off);
156 
157 	befs_debug(sb, "<--- %s for inode %lu, block %ld, disk address %lu",
158 		  __func__, (unsigned long)inode->i_ino, (long)block,
159 		  (unsigned long)disk_off);
160 
161 	return 0;
162 }
163 
164 static struct dentry *
165 befs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
166 {
167 	struct inode *inode;
168 	struct super_block *sb = dir->i_sb;
169 	const befs_data_stream *ds = &BEFS_I(dir)->i_data.ds;
170 	befs_off_t offset;
171 	int ret;
172 	int utfnamelen;
173 	char *utfname;
174 	const char *name = dentry->d_name.name;
175 
176 	befs_debug(sb, "---> %s name %pd inode %ld", __func__,
177 		   dentry, dir->i_ino);
178 
179 	/* Convert to UTF-8 */
180 	if (BEFS_SB(sb)->nls) {
181 		ret =
182 		    befs_nls2utf(sb, name, strlen(name), &utfname, &utfnamelen);
183 		if (ret < 0) {
184 			befs_debug(sb, "<--- %s ERROR", __func__);
185 			return ERR_PTR(ret);
186 		}
187 		ret = befs_btree_find(sb, ds, utfname, &offset);
188 		kfree(utfname);
189 
190 	} else {
191 		ret = befs_btree_find(sb, ds, name, &offset);
192 	}
193 
194 	if (ret == BEFS_BT_NOT_FOUND) {
195 		befs_debug(sb, "<--- %s %pd not found", __func__, dentry);
196 		d_add(dentry, NULL);
197 		return ERR_PTR(-ENOENT);
198 
199 	} else if (ret != BEFS_OK || offset == 0) {
200 		befs_error(sb, "<--- %s Error", __func__);
201 		return ERR_PTR(-ENODATA);
202 	}
203 
204 	inode = befs_iget(dir->i_sb, (ino_t) offset);
205 	if (IS_ERR(inode))
206 		return ERR_CAST(inode);
207 
208 	d_add(dentry, inode);
209 
210 	befs_debug(sb, "<--- %s", __func__);
211 
212 	return NULL;
213 }
214 
215 static int
216 befs_readdir(struct file *file, struct dir_context *ctx)
217 {
218 	struct inode *inode = file_inode(file);
219 	struct super_block *sb = inode->i_sb;
220 	const befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
221 	befs_off_t value;
222 	int result;
223 	size_t keysize;
224 	char keybuf[BEFS_NAME_LEN + 1];
225 
226 	befs_debug(sb, "---> %s name %pD, inode %ld, ctx->pos %lld",
227 		  __func__, file, inode->i_ino, ctx->pos);
228 
229 	while (1) {
230 		result = befs_btree_read(sb, ds, ctx->pos, BEFS_NAME_LEN + 1,
231 					 keybuf, &keysize, &value);
232 
233 		if (result == BEFS_ERR) {
234 			befs_debug(sb, "<--- %s ERROR", __func__);
235 			befs_error(sb, "IO error reading %pD (inode %lu)",
236 				   file, inode->i_ino);
237 			return -EIO;
238 
239 		} else if (result == BEFS_BT_END) {
240 			befs_debug(sb, "<--- %s END", __func__);
241 			return 0;
242 
243 		} else if (result == BEFS_BT_EMPTY) {
244 			befs_debug(sb, "<--- %s Empty directory", __func__);
245 			return 0;
246 		}
247 
248 		/* Convert to NLS */
249 		if (BEFS_SB(sb)->nls) {
250 			char *nlsname;
251 			int nlsnamelen;
252 
253 			result =
254 			    befs_utf2nls(sb, keybuf, keysize, &nlsname,
255 					 &nlsnamelen);
256 			if (result < 0) {
257 				befs_debug(sb, "<--- %s ERROR", __func__);
258 				return result;
259 			}
260 			if (!dir_emit(ctx, nlsname, nlsnamelen,
261 				      (ino_t) value, DT_UNKNOWN)) {
262 				kfree(nlsname);
263 				return 0;
264 			}
265 			kfree(nlsname);
266 		} else {
267 			if (!dir_emit(ctx, keybuf, keysize,
268 				      (ino_t) value, DT_UNKNOWN))
269 				return 0;
270 		}
271 		ctx->pos++;
272 	}
273 }
274 
275 static struct inode *
276 befs_alloc_inode(struct super_block *sb)
277 {
278 	struct befs_inode_info *bi;
279 
280 	bi = kmem_cache_alloc(befs_inode_cachep, GFP_KERNEL);
281 	if (!bi)
282 		return NULL;
283 	return &bi->vfs_inode;
284 }
285 
286 static void befs_i_callback(struct rcu_head *head)
287 {
288 	struct inode *inode = container_of(head, struct inode, i_rcu);
289 	kmem_cache_free(befs_inode_cachep, BEFS_I(inode));
290 }
291 
292 static void befs_destroy_inode(struct inode *inode)
293 {
294 	call_rcu(&inode->i_rcu, befs_i_callback);
295 }
296 
297 static void init_once(void *foo)
298 {
299 	struct befs_inode_info *bi = (struct befs_inode_info *) foo;
300 
301 	inode_init_once(&bi->vfs_inode);
302 }
303 
304 static struct inode *befs_iget(struct super_block *sb, unsigned long ino)
305 {
306 	struct buffer_head *bh;
307 	befs_inode *raw_inode;
308 	struct befs_sb_info *befs_sb = BEFS_SB(sb);
309 	struct befs_inode_info *befs_ino;
310 	struct inode *inode;
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 = sb_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 = &page_symlink_inode_operations;
408 			inode_nohighmem(inode);
409 			inode->i_mapping->a_ops = &befs_symlink_aops;
410 		} else {
411 			inode->i_link = befs_ino->i_data.symlink;
412 			inode->i_op = &simple_symlink_inode_operations;
413 		}
414 	} else {
415 		befs_error(sb, "Inode %lu is not a regular file, "
416 			   "directory or symlink. THAT IS WRONG! BeFS has no "
417 			   "on disk special files", inode->i_ino);
418 		goto unacquire_bh;
419 	}
420 
421 	brelse(bh);
422 	befs_debug(sb, "<--- %s", __func__);
423 	unlock_new_inode(inode);
424 	return inode;
425 
426 unacquire_bh:
427 	brelse(bh);
428 
429 unacquire_none:
430 	iget_failed(inode);
431 	befs_debug(sb, "<--- %s - Bad inode", __func__);
432 	return ERR_PTR(-EIO);
433 }
434 
435 /* Initialize the inode cache. Called at fs setup.
436  *
437  * Taken from NFS implementation by Al Viro.
438  */
439 static int __init
440 befs_init_inodecache(void)
441 {
442 	befs_inode_cachep = kmem_cache_create("befs_inode_cache",
443 					      sizeof (struct befs_inode_info),
444 					      0, (SLAB_RECLAIM_ACCOUNT|
445 						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
446 					      init_once);
447 	if (befs_inode_cachep == NULL)
448 		return -ENOMEM;
449 
450 	return 0;
451 }
452 
453 /* Called at fs teardown.
454  *
455  * Taken from NFS implementation by Al Viro.
456  */
457 static void
458 befs_destroy_inodecache(void)
459 {
460 	/*
461 	 * Make sure all delayed rcu free inodes are flushed before we
462 	 * destroy cache.
463 	 */
464 	rcu_barrier();
465 	kmem_cache_destroy(befs_inode_cachep);
466 }
467 
468 /*
469  * The inode of symbolic link is different to data stream.
470  * The data stream become link name. Unless the LONG_SYMLINK
471  * flag is set.
472  */
473 static int befs_symlink_readpage(struct file *unused, struct page *page)
474 {
475 	struct inode *inode = page->mapping->host;
476 	struct super_block *sb = inode->i_sb;
477 	struct befs_inode_info *befs_ino = BEFS_I(inode);
478 	befs_data_stream *data = &befs_ino->i_data.ds;
479 	befs_off_t len = data->size;
480 	char *link = page_address(page);
481 
482 	if (len == 0 || len > PAGE_SIZE) {
483 		befs_error(sb, "Long symlink with illegal length");
484 		goto fail;
485 	}
486 	befs_debug(sb, "Follow long symlink");
487 
488 	if (befs_read_lsymlink(sb, data, link, len) != len) {
489 		befs_error(sb, "Failed to read entire long symlink");
490 		goto fail;
491 	}
492 	link[len - 1] = '\0';
493 	SetPageUptodate(page);
494 	unlock_page(page);
495 	return 0;
496 fail:
497 	SetPageError(page);
498 	unlock_page(page);
499 	return -EIO;
500 }
501 
502 /*
503  * UTF-8 to NLS charset convert routine
504  *
505  * Uses uni2char() / char2uni() rather than the nls tables directly
506  */
507 static int
508 befs_utf2nls(struct super_block *sb, const char *in,
509 	     int in_len, char **out, int *out_len)
510 {
511 	struct nls_table *nls = BEFS_SB(sb)->nls;
512 	int i, o;
513 	unicode_t uni;
514 	int unilen, utflen;
515 	char *result;
516 	/* The utf8->nls conversion won't make the final nls string bigger
517 	 * than the utf one, but if the string is pure ascii they'll have the
518 	 * same width and an extra char is needed to save the additional \0
519 	 */
520 	int maxlen = in_len + 1;
521 
522 	befs_debug(sb, "---> %s", __func__);
523 
524 	if (!nls) {
525 		befs_error(sb, "%s called with no NLS table loaded", __func__);
526 		return -EINVAL;
527 	}
528 
529 	*out = result = kmalloc(maxlen, GFP_NOFS);
530 	if (!*out)
531 		return -ENOMEM;
532 
533 	for (i = o = 0; i < in_len; i += utflen, o += unilen) {
534 
535 		/* convert from UTF-8 to Unicode */
536 		utflen = utf8_to_utf32(&in[i], in_len - i, &uni);
537 		if (utflen < 0)
538 			goto conv_err;
539 
540 		/* convert from Unicode to nls */
541 		if (uni > MAX_WCHAR_T)
542 			goto conv_err;
543 		unilen = nls->uni2char(uni, &result[o], in_len - o);
544 		if (unilen < 0)
545 			goto conv_err;
546 	}
547 	result[o] = '\0';
548 	*out_len = o;
549 
550 	befs_debug(sb, "<--- %s", __func__);
551 
552 	return o;
553 
554 conv_err:
555 	befs_error(sb, "Name using character set %s contains a character that "
556 		   "cannot be converted to unicode.", nls->charset);
557 	befs_debug(sb, "<--- %s", __func__);
558 	kfree(result);
559 	return -EILSEQ;
560 }
561 
562 /**
563  * befs_nls2utf - Convert NLS string to utf8 encodeing
564  * @sb: Superblock
565  * @in: Input string buffer in NLS format
566  * @in_len: Length of input string in bytes
567  * @out: The output string in UTF-8 format
568  * @out_len: Length of the output buffer
569  *
570  * Converts input string @in, which is in the format of the loaded NLS map,
571  * into a utf8 string.
572  *
573  * The destination string @out is allocated by this function and the caller is
574  * responsible for freeing it with kfree()
575  *
576  * On return, *@out_len is the length of @out in bytes.
577  *
578  * On success, the return value is the number of utf8 characters written to
579  * the output buffer @out.
580  *
581  * On Failure, a negative number coresponding to the error code is returned.
582  */
583 
584 static int
585 befs_nls2utf(struct super_block *sb, const char *in,
586 	     int in_len, char **out, int *out_len)
587 {
588 	struct nls_table *nls = BEFS_SB(sb)->nls;
589 	int i, o;
590 	wchar_t uni;
591 	int unilen, utflen;
592 	char *result;
593 	/*
594 	 * There are nls characters that will translate to 3-chars-wide UTF-8
595 	 * characters, an additional byte is needed to save the final \0
596 	 * in special cases
597 	 */
598 	int maxlen = (3 * in_len) + 1;
599 
600 	befs_debug(sb, "---> %s\n", __func__);
601 
602 	if (!nls) {
603 		befs_error(sb, "%s called with no NLS table loaded.",
604 			   __func__);
605 		return -EINVAL;
606 	}
607 
608 	*out = result = kmalloc(maxlen, GFP_NOFS);
609 	if (!*out) {
610 		*out_len = 0;
611 		return -ENOMEM;
612 	}
613 
614 	for (i = o = 0; i < in_len; i += unilen, o += utflen) {
615 
616 		/* convert from nls to unicode */
617 		unilen = nls->char2uni(&in[i], in_len - i, &uni);
618 		if (unilen < 0)
619 			goto conv_err;
620 
621 		/* convert from unicode to UTF-8 */
622 		utflen = utf32_to_utf8(uni, &result[o], 3);
623 		if (utflen <= 0)
624 			goto conv_err;
625 	}
626 
627 	result[o] = '\0';
628 	*out_len = o;
629 
630 	befs_debug(sb, "<--- %s", __func__);
631 
632 	return i;
633 
634 conv_err:
635 	befs_error(sb, "Name using character set %s contains a character that "
636 		   "cannot be converted to unicode.", nls->charset);
637 	befs_debug(sb, "<--- %s", __func__);
638 	kfree(result);
639 	return -EILSEQ;
640 }
641 
642 static struct inode *befs_nfs_get_inode(struct super_block *sb, uint64_t ino,
643 					 uint32_t generation)
644 {
645 	/* No need to handle i_generation */
646 	return befs_iget(sb, ino);
647 }
648 
649 /*
650  * Map a NFS file handle to a corresponding dentry
651  */
652 static struct dentry *befs_fh_to_dentry(struct super_block *sb,
653 				struct fid *fid, int fh_len, int fh_type)
654 {
655 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
656 				    befs_nfs_get_inode);
657 }
658 
659 /*
660  * Find the parent for a file specified by NFS handle
661  */
662 static struct dentry *befs_fh_to_parent(struct super_block *sb,
663 				struct fid *fid, int fh_len, int fh_type)
664 {
665 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
666 				    befs_nfs_get_inode);
667 }
668 
669 enum {
670 	Opt_uid, Opt_gid, Opt_charset, Opt_debug, Opt_err,
671 };
672 
673 static const match_table_t befs_tokens = {
674 	{Opt_uid, "uid=%d"},
675 	{Opt_gid, "gid=%d"},
676 	{Opt_charset, "iocharset=%s"},
677 	{Opt_debug, "debug"},
678 	{Opt_err, NULL}
679 };
680 
681 static int
682 parse_options(char *options, struct befs_mount_options *opts)
683 {
684 	char *p;
685 	substring_t args[MAX_OPT_ARGS];
686 	int option;
687 	kuid_t uid;
688 	kgid_t gid;
689 
690 	/* Initialize options */
691 	opts->uid = GLOBAL_ROOT_UID;
692 	opts->gid = GLOBAL_ROOT_GID;
693 	opts->use_uid = 0;
694 	opts->use_gid = 0;
695 	opts->iocharset = NULL;
696 	opts->debug = 0;
697 
698 	if (!options)
699 		return 1;
700 
701 	while ((p = strsep(&options, ",")) != NULL) {
702 		int token;
703 
704 		if (!*p)
705 			continue;
706 
707 		token = match_token(p, befs_tokens, args);
708 		switch (token) {
709 		case Opt_uid:
710 			if (match_int(&args[0], &option))
711 				return 0;
712 			uid = INVALID_UID;
713 			if (option >= 0)
714 				uid = make_kuid(current_user_ns(), option);
715 			if (!uid_valid(uid)) {
716 				pr_err("Invalid uid %d, "
717 				       "using default\n", option);
718 				break;
719 			}
720 			opts->uid = uid;
721 			opts->use_uid = 1;
722 			break;
723 		case Opt_gid:
724 			if (match_int(&args[0], &option))
725 				return 0;
726 			gid = INVALID_GID;
727 			if (option >= 0)
728 				gid = make_kgid(current_user_ns(), option);
729 			if (!gid_valid(gid)) {
730 				pr_err("Invalid gid %d, "
731 				       "using default\n", option);
732 				break;
733 			}
734 			opts->gid = gid;
735 			opts->use_gid = 1;
736 			break;
737 		case Opt_charset:
738 			kfree(opts->iocharset);
739 			opts->iocharset = match_strdup(&args[0]);
740 			if (!opts->iocharset) {
741 				pr_err("allocation failure for "
742 				       "iocharset string\n");
743 				return 0;
744 			}
745 			break;
746 		case Opt_debug:
747 			opts->debug = 1;
748 			break;
749 		default:
750 			pr_err("Unrecognized mount option \"%s\" "
751 			       "or missing value\n", p);
752 			return 0;
753 		}
754 	}
755 	return 1;
756 }
757 
758 /* This function has the responsibiltiy of getting the
759  * filesystem ready for unmounting.
760  * Basically, we free everything that we allocated in
761  * befs_read_inode
762  */
763 static void
764 befs_put_super(struct super_block *sb)
765 {
766 	kfree(BEFS_SB(sb)->mount_opts.iocharset);
767 	BEFS_SB(sb)->mount_opts.iocharset = NULL;
768 	unload_nls(BEFS_SB(sb)->nls);
769 	kfree(sb->s_fs_info);
770 	sb->s_fs_info = NULL;
771 }
772 
773 /* Allocate private field of the superblock, fill it.
774  *
775  * Finish filling the public superblock fields
776  * Make the root directory
777  * Load a set of NLS translations if needed.
778  */
779 static int
780 befs_fill_super(struct super_block *sb, void *data, int silent)
781 {
782 	struct buffer_head *bh;
783 	struct befs_sb_info *befs_sb;
784 	befs_super_block *disk_sb;
785 	struct inode *root;
786 	long ret = -EINVAL;
787 	const unsigned long sb_block = 0;
788 	const off_t x86_sb_off = 512;
789 	int blocksize;
790 
791 	save_mount_options(sb, data);
792 
793 	sb->s_fs_info = kzalloc(sizeof(*befs_sb), GFP_KERNEL);
794 	if (sb->s_fs_info == NULL)
795 		goto unacquire_none;
796 
797 	befs_sb = BEFS_SB(sb);
798 
799 	if (!parse_options((char *) data, &befs_sb->mount_opts)) {
800 		if (!silent)
801 			befs_error(sb, "cannot parse mount options");
802 		goto unacquire_priv_sbp;
803 	}
804 
805 	befs_debug(sb, "---> %s", __func__);
806 
807 	if (!(sb->s_flags & MS_RDONLY)) {
808 		befs_warning(sb,
809 			     "No write support. Marking filesystem read-only");
810 		sb->s_flags |= MS_RDONLY;
811 	}
812 
813 	/*
814 	 * Set dummy blocksize to read super block.
815 	 * Will be set to real fs blocksize later.
816 	 *
817 	 * Linux 2.4.10 and later refuse to read blocks smaller than
818 	 * the logical block size for the device. But we also need to read at
819 	 * least 1k to get the second 512 bytes of the volume.
820 	 */
821 	blocksize = sb_min_blocksize(sb, 1024);
822 	if (!blocksize) {
823 		if (!silent)
824 			befs_error(sb, "unable to set blocksize");
825 		goto unacquire_priv_sbp;
826 	}
827 
828 	bh = sb_bread(sb, sb_block);
829 	if (!bh) {
830 		if (!silent)
831 			befs_error(sb, "unable to read superblock");
832 		goto unacquire_priv_sbp;
833 	}
834 
835 	/* account for offset of super block on x86 */
836 	disk_sb = (befs_super_block *) bh->b_data;
837 	if ((disk_sb->magic1 == BEFS_SUPER_MAGIC1_LE) ||
838 	    (disk_sb->magic1 == BEFS_SUPER_MAGIC1_BE)) {
839 		befs_debug(sb, "Using PPC superblock location");
840 	} else {
841 		befs_debug(sb, "Using x86 superblock location");
842 		disk_sb =
843 		    (befs_super_block *) ((void *) bh->b_data + x86_sb_off);
844 	}
845 
846 	if ((befs_load_sb(sb, disk_sb) != BEFS_OK) ||
847 	    (befs_check_sb(sb) != BEFS_OK))
848 		goto unacquire_bh;
849 
850 	befs_dump_super_block(sb, disk_sb);
851 
852 	brelse(bh);
853 
854 	if (befs_sb->num_blocks > ~((sector_t)0)) {
855 		if (!silent)
856 			befs_error(sb, "blocks count: %llu is larger than the host can use",
857 					befs_sb->num_blocks);
858 		goto unacquire_priv_sbp;
859 	}
860 
861 	/*
862 	 * set up enough so that it can read an inode
863 	 * Fill in kernel superblock fields from private sb
864 	 */
865 	sb->s_magic = BEFS_SUPER_MAGIC;
866 	/* Set real blocksize of fs */
867 	sb_set_blocksize(sb, (ulong) befs_sb->block_size);
868 	sb->s_op = &befs_sops;
869 	sb->s_export_op = &befs_export_operations;
870 	root = befs_iget(sb, iaddr2blockno(sb, &(befs_sb->root_dir)));
871 	if (IS_ERR(root)) {
872 		ret = PTR_ERR(root);
873 		goto unacquire_priv_sbp;
874 	}
875 	sb->s_root = d_make_root(root);
876 	if (!sb->s_root) {
877 		if (!silent)
878 			befs_error(sb, "get root inode failed");
879 		goto unacquire_priv_sbp;
880 	}
881 
882 	/* load nls library */
883 	if (befs_sb->mount_opts.iocharset) {
884 		befs_debug(sb, "Loading nls: %s",
885 			   befs_sb->mount_opts.iocharset);
886 		befs_sb->nls = load_nls(befs_sb->mount_opts.iocharset);
887 		if (!befs_sb->nls) {
888 			befs_warning(sb, "Cannot load nls %s"
889 					" loading default nls",
890 					befs_sb->mount_opts.iocharset);
891 			befs_sb->nls = load_nls_default();
892 		}
893 	/* load default nls if none is specified  in mount options */
894 	} else {
895 		befs_debug(sb, "Loading default nls");
896 		befs_sb->nls = load_nls_default();
897 	}
898 
899 	return 0;
900 
901 unacquire_bh:
902 	brelse(bh);
903 
904 unacquire_priv_sbp:
905 	kfree(befs_sb->mount_opts.iocharset);
906 	kfree(sb->s_fs_info);
907 	sb->s_fs_info = NULL;
908 
909 unacquire_none:
910 	return ret;
911 }
912 
913 static int
914 befs_remount(struct super_block *sb, int *flags, char *data)
915 {
916 	sync_filesystem(sb);
917 	if (!(*flags & MS_RDONLY))
918 		return -EINVAL;
919 	return 0;
920 }
921 
922 static int
923 befs_statfs(struct dentry *dentry, struct kstatfs *buf)
924 {
925 	struct super_block *sb = dentry->d_sb;
926 	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
927 
928 	befs_debug(sb, "---> %s", __func__);
929 
930 	buf->f_type = BEFS_SUPER_MAGIC;
931 	buf->f_bsize = sb->s_blocksize;
932 	buf->f_blocks = BEFS_SB(sb)->num_blocks;
933 	buf->f_bfree = BEFS_SB(sb)->num_blocks - BEFS_SB(sb)->used_blocks;
934 	buf->f_bavail = buf->f_bfree;
935 	buf->f_files = 0;	/* UNKNOWN */
936 	buf->f_ffree = 0;	/* UNKNOWN */
937 	buf->f_fsid.val[0] = (u32)id;
938 	buf->f_fsid.val[1] = (u32)(id >> 32);
939 	buf->f_namelen = BEFS_NAME_LEN;
940 
941 	befs_debug(sb, "<--- %s", __func__);
942 
943 	return 0;
944 }
945 
946 static struct dentry *
947 befs_mount(struct file_system_type *fs_type, int flags, const char *dev_name,
948 	    void *data)
949 {
950 	return mount_bdev(fs_type, flags, dev_name, data, befs_fill_super);
951 }
952 
953 static struct file_system_type befs_fs_type = {
954 	.owner		= THIS_MODULE,
955 	.name		= "befs",
956 	.mount		= befs_mount,
957 	.kill_sb	= kill_block_super,
958 	.fs_flags	= FS_REQUIRES_DEV,
959 };
960 MODULE_ALIAS_FS("befs");
961 
962 static int __init
963 init_befs_fs(void)
964 {
965 	int err;
966 
967 	pr_info("version: %s\n", BEFS_VERSION);
968 
969 	err = befs_init_inodecache();
970 	if (err)
971 		goto unacquire_none;
972 
973 	err = register_filesystem(&befs_fs_type);
974 	if (err)
975 		goto unacquire_inodecache;
976 
977 	return 0;
978 
979 unacquire_inodecache:
980 	befs_destroy_inodecache();
981 
982 unacquire_none:
983 	return err;
984 }
985 
986 static void __exit
987 exit_befs_fs(void)
988 {
989 	befs_destroy_inodecache();
990 
991 	unregister_filesystem(&befs_fs_type);
992 }
993 
994 /*
995  * Macros that typecheck the init and exit functions,
996  * ensures that they are called at init and cleanup,
997  * and eliminates warnings about unused functions.
998  */
999 module_init(init_befs_fs)
1000 module_exit(exit_befs_fs)
1001