1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/fs/befs/linuxvfs.c
4 *
5 * Copyright (C) 2001 Will Dyson <will_dyson@pobox.com
6 *
7 */
8
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 #include <linux/fs.h>
14 #include <linux/errno.h>
15 #include <linux/stat.h>
16 #include <linux/nls.h>
17 #include <linux/buffer_head.h>
18 #include <linux/vfs.h>
19 #include <linux/parser.h>
20 #include <linux/namei.h>
21 #include <linux/sched.h>
22 #include <linux/cred.h>
23 #include <linux/exportfs.h>
24 #include <linux/seq_file.h>
25 #include <linux/blkdev.h>
26
27 #include "befs.h"
28 #include "btree.h"
29 #include "inode.h"
30 #include "datastream.h"
31 #include "super.h"
32 #include "io.h"
33
34 MODULE_DESCRIPTION("BeOS File System (BeFS) driver");
35 MODULE_AUTHOR("Will Dyson");
36 MODULE_LICENSE("GPL");
37
38 /* The units the vfs expects inode->i_blocks to be in */
39 #define VFS_BLOCK_SIZE 512
40
41 static int befs_readdir(struct file *, struct dir_context *);
42 static int befs_get_block(struct inode *, sector_t, struct buffer_head *, int);
43 static int befs_read_folio(struct file *file, struct folio *folio);
44 static sector_t befs_bmap(struct address_space *mapping, sector_t block);
45 static struct dentry *befs_lookup(struct inode *, struct dentry *,
46 unsigned int);
47 static struct inode *befs_iget(struct super_block *, unsigned long);
48 static struct inode *befs_alloc_inode(struct super_block *sb);
49 static void befs_free_inode(struct inode *inode);
50 static void befs_destroy_inodecache(void);
51 static int befs_symlink_read_folio(struct file *, struct folio *);
52 static int befs_utf2nls(struct super_block *sb, const char *in, int in_len,
53 char **out, int *out_len);
54 static int befs_nls2utf(struct super_block *sb, const char *in, int in_len,
55 char **out, int *out_len);
56 static void befs_put_super(struct super_block *);
57 static int befs_remount(struct super_block *, int *, char *);
58 static int befs_statfs(struct dentry *, struct kstatfs *);
59 static int befs_show_options(struct seq_file *, struct dentry *);
60 static int parse_options(char *, struct befs_mount_options *);
61 static struct dentry *befs_fh_to_dentry(struct super_block *sb,
62 struct fid *fid, int fh_len, int fh_type);
63 static struct dentry *befs_fh_to_parent(struct super_block *sb,
64 struct fid *fid, int fh_len, int fh_type);
65 static struct dentry *befs_get_parent(struct dentry *child);
66
67 static const struct super_operations befs_sops = {
68 .alloc_inode = befs_alloc_inode, /* allocate a new inode */
69 .free_inode = befs_free_inode, /* deallocate an inode */
70 .put_super = befs_put_super, /* uninit super */
71 .statfs = befs_statfs, /* statfs */
72 .remount_fs = befs_remount,
73 .show_options = befs_show_options,
74 };
75
76 /* slab cache for befs_inode_info objects */
77 static struct kmem_cache *befs_inode_cachep;
78
79 static const struct file_operations befs_dir_operations = {
80 .read = generic_read_dir,
81 .iterate_shared = befs_readdir,
82 .llseek = generic_file_llseek,
83 };
84
85 static const struct inode_operations befs_dir_inode_operations = {
86 .lookup = befs_lookup,
87 };
88
89 static const struct address_space_operations befs_aops = {
90 .read_folio = befs_read_folio,
91 .bmap = befs_bmap,
92 };
93
94 static const struct address_space_operations befs_symlink_aops = {
95 .read_folio = befs_symlink_read_folio,
96 };
97
98 static const struct export_operations befs_export_operations = {
99 .encode_fh = generic_encode_ino32_fh,
100 .fh_to_dentry = befs_fh_to_dentry,
101 .fh_to_parent = befs_fh_to_parent,
102 .get_parent = befs_get_parent,
103 };
104
105 /*
106 * Called by generic_file_read() to read a folio of data
107 *
108 * In turn, simply calls a generic block read function and
109 * passes it the address of befs_get_block, for mapping file
110 * positions to disk blocks.
111 */
befs_read_folio(struct file * file,struct folio * folio)112 static int befs_read_folio(struct file *file, struct folio *folio)
113 {
114 return block_read_full_folio(folio, befs_get_block);
115 }
116
117 static sector_t
befs_bmap(struct address_space * mapping,sector_t block)118 befs_bmap(struct address_space *mapping, sector_t block)
119 {
120 return generic_block_bmap(mapping, block, befs_get_block);
121 }
122
123 /*
124 * Generic function to map a file position (block) to a
125 * disk offset (passed back in bh_result).
126 *
127 * Used by many higher level functions.
128 *
129 * Calls befs_fblock2brun() in datastream.c to do the real work.
130 */
131
132 static int
befs_get_block(struct inode * inode,sector_t block,struct buffer_head * bh_result,int create)133 befs_get_block(struct inode *inode, sector_t block,
134 struct buffer_head *bh_result, int create)
135 {
136 struct super_block *sb = inode->i_sb;
137 befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
138 befs_block_run run = BAD_IADDR;
139 int res;
140 ulong disk_off;
141
142 befs_debug(sb, "---> befs_get_block() for inode %lu, block %ld",
143 (unsigned long)inode->i_ino, (long)block);
144 if (create) {
145 befs_error(sb, "befs_get_block() was asked to write to "
146 "block %ld in inode %lu", (long)block,
147 (unsigned long)inode->i_ino);
148 return -EPERM;
149 }
150
151 res = befs_fblock2brun(sb, ds, block, &run);
152 if (res != BEFS_OK) {
153 befs_error(sb,
154 "<--- %s for inode %lu, block %ld ERROR",
155 __func__, (unsigned long)inode->i_ino,
156 (long)block);
157 return -EFBIG;
158 }
159
160 disk_off = (ulong) iaddr2blockno(sb, &run);
161
162 map_bh(bh_result, inode->i_sb, disk_off);
163
164 befs_debug(sb, "<--- %s for inode %lu, block %ld, disk address %lu",
165 __func__, (unsigned long)inode->i_ino, (long)block,
166 (unsigned long)disk_off);
167
168 return 0;
169 }
170
171 static struct dentry *
befs_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)172 befs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
173 {
174 struct inode *inode;
175 struct super_block *sb = dir->i_sb;
176 const befs_data_stream *ds = &BEFS_I(dir)->i_data.ds;
177 befs_off_t offset;
178 int ret;
179 int utfnamelen;
180 char *utfname;
181 const char *name = dentry->d_name.name;
182
183 befs_debug(sb, "---> %s name %pd inode %ld", __func__,
184 dentry, dir->i_ino);
185
186 /* Convert to UTF-8 */
187 if (BEFS_SB(sb)->nls) {
188 ret =
189 befs_nls2utf(sb, name, strlen(name), &utfname, &utfnamelen);
190 if (ret < 0) {
191 befs_debug(sb, "<--- %s ERROR", __func__);
192 return ERR_PTR(ret);
193 }
194 ret = befs_btree_find(sb, ds, utfname, &offset);
195 kfree(utfname);
196
197 } else {
198 ret = befs_btree_find(sb, ds, name, &offset);
199 }
200
201 if (ret == BEFS_BT_NOT_FOUND) {
202 befs_debug(sb, "<--- %s %pd not found", __func__, dentry);
203 inode = NULL;
204 } else if (ret != BEFS_OK || offset == 0) {
205 befs_error(sb, "<--- %s Error", __func__);
206 inode = ERR_PTR(-ENODATA);
207 } else {
208 inode = befs_iget(dir->i_sb, (ino_t) offset);
209 }
210 befs_debug(sb, "<--- %s", __func__);
211
212 return d_splice_alias(inode, dentry);
213 }
214
215 static int
befs_readdir(struct file * file,struct dir_context * ctx)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 *
befs_alloc_inode(struct super_block * sb)276 befs_alloc_inode(struct super_block *sb)
277 {
278 struct befs_inode_info *bi;
279
280 bi = alloc_inode_sb(sb, befs_inode_cachep, GFP_KERNEL);
281 if (!bi)
282 return NULL;
283 return &bi->vfs_inode;
284 }
285
befs_free_inode(struct inode * inode)286 static void befs_free_inode(struct inode *inode)
287 {
288 kmem_cache_free(befs_inode_cachep, BEFS_I(inode));
289 }
290
init_once(void * foo)291 static void init_once(void *foo)
292 {
293 struct befs_inode_info *bi = (struct befs_inode_info *) foo;
294
295 inode_init_once(&bi->vfs_inode);
296 }
297
befs_iget(struct super_block * sb,unsigned long ino)298 static struct inode *befs_iget(struct super_block *sb, unsigned long ino)
299 {
300 struct buffer_head *bh;
301 befs_inode *raw_inode;
302 struct befs_sb_info *befs_sb = BEFS_SB(sb);
303 struct befs_inode_info *befs_ino;
304 struct inode *inode;
305
306 befs_debug(sb, "---> %s inode = %lu", __func__, ino);
307
308 inode = iget_locked(sb, ino);
309 if (!inode)
310 return ERR_PTR(-ENOMEM);
311 if (!(inode->i_state & I_NEW))
312 return inode;
313
314 befs_ino = BEFS_I(inode);
315
316 /* convert from vfs's inode number to befs's inode number */
317 befs_ino->i_inode_num = blockno2iaddr(sb, inode->i_ino);
318
319 befs_debug(sb, " real inode number [%u, %hu, %hu]",
320 befs_ino->i_inode_num.allocation_group,
321 befs_ino->i_inode_num.start, befs_ino->i_inode_num.len);
322
323 bh = sb_bread(sb, inode->i_ino);
324 if (!bh) {
325 befs_error(sb, "unable to read inode block - "
326 "inode = %lu", inode->i_ino);
327 goto unacquire_none;
328 }
329
330 raw_inode = (befs_inode *) bh->b_data;
331
332 befs_dump_inode(sb, raw_inode);
333
334 if (befs_check_inode(sb, raw_inode, inode->i_ino) != BEFS_OK) {
335 befs_error(sb, "Bad inode: %lu", inode->i_ino);
336 goto unacquire_bh;
337 }
338
339 inode->i_mode = (umode_t) fs32_to_cpu(sb, raw_inode->mode);
340
341 /*
342 * set uid and gid. But since current BeOS is single user OS, so
343 * you can change by "uid" or "gid" options.
344 */
345
346 inode->i_uid = befs_sb->mount_opts.use_uid ?
347 befs_sb->mount_opts.uid :
348 make_kuid(&init_user_ns, fs32_to_cpu(sb, raw_inode->uid));
349 inode->i_gid = befs_sb->mount_opts.use_gid ?
350 befs_sb->mount_opts.gid :
351 make_kgid(&init_user_ns, fs32_to_cpu(sb, raw_inode->gid));
352
353 set_nlink(inode, 1);
354
355 /*
356 * BEFS's time is 64 bits, but current VFS is 32 bits...
357 * BEFS don't have access time. Nor inode change time. VFS
358 * doesn't have creation time.
359 * Also, the lower 16 bits of the last_modified_time and
360 * create_time are just a counter to help ensure uniqueness
361 * for indexing purposes. (PFD, page 54)
362 */
363
364 inode_set_mtime(inode,
365 fs64_to_cpu(sb, raw_inode->last_modified_time) >> 16,
366 0);/* lower 16 bits are not a time */
367 inode_set_ctime_to_ts(inode, inode_get_mtime(inode));
368 inode_set_atime_to_ts(inode, inode_get_mtime(inode));
369
370 befs_ino->i_inode_num = fsrun_to_cpu(sb, raw_inode->inode_num);
371 befs_ino->i_parent = fsrun_to_cpu(sb, raw_inode->parent);
372 befs_ino->i_attribute = fsrun_to_cpu(sb, raw_inode->attributes);
373 befs_ino->i_flags = fs32_to_cpu(sb, raw_inode->flags);
374
375 if (S_ISLNK(inode->i_mode) && !(befs_ino->i_flags & BEFS_LONG_SYMLINK)){
376 inode->i_size = 0;
377 inode->i_blocks = befs_sb->block_size / VFS_BLOCK_SIZE;
378 strscpy(befs_ino->i_data.symlink, raw_inode->data.symlink,
379 BEFS_SYMLINK_LEN);
380 } else {
381 int num_blks;
382
383 befs_ino->i_data.ds =
384 fsds_to_cpu(sb, &raw_inode->data.datastream);
385
386 num_blks = befs_count_blocks(sb, &befs_ino->i_data.ds);
387 inode->i_blocks =
388 num_blks * (befs_sb->block_size / VFS_BLOCK_SIZE);
389 inode->i_size = befs_ino->i_data.ds.size;
390 }
391
392 inode->i_mapping->a_ops = &befs_aops;
393
394 if (S_ISREG(inode->i_mode)) {
395 inode->i_fop = &generic_ro_fops;
396 } else if (S_ISDIR(inode->i_mode)) {
397 inode->i_op = &befs_dir_inode_operations;
398 inode->i_fop = &befs_dir_operations;
399 } else if (S_ISLNK(inode->i_mode)) {
400 if (befs_ino->i_flags & BEFS_LONG_SYMLINK) {
401 inode->i_op = &page_symlink_inode_operations;
402 inode_nohighmem(inode);
403 inode->i_mapping->a_ops = &befs_symlink_aops;
404 } else {
405 inode->i_link = befs_ino->i_data.symlink;
406 inode->i_op = &simple_symlink_inode_operations;
407 }
408 } else {
409 befs_error(sb, "Inode %lu is not a regular file, "
410 "directory or symlink. THAT IS WRONG! BeFS has no "
411 "on disk special files", inode->i_ino);
412 goto unacquire_bh;
413 }
414
415 brelse(bh);
416 befs_debug(sb, "<--- %s", __func__);
417 unlock_new_inode(inode);
418 return inode;
419
420 unacquire_bh:
421 brelse(bh);
422
423 unacquire_none:
424 iget_failed(inode);
425 befs_debug(sb, "<--- %s - Bad inode", __func__);
426 return ERR_PTR(-EIO);
427 }
428
429 /* Initialize the inode cache. Called at fs setup.
430 *
431 * Taken from NFS implementation by Al Viro.
432 */
433 static int __init
befs_init_inodecache(void)434 befs_init_inodecache(void)
435 {
436 befs_inode_cachep = kmem_cache_create_usercopy("befs_inode_cache",
437 sizeof(struct befs_inode_info), 0,
438 SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT,
439 offsetof(struct befs_inode_info,
440 i_data.symlink),
441 sizeof_field(struct befs_inode_info,
442 i_data.symlink),
443 init_once);
444 if (befs_inode_cachep == NULL)
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
befs_destroy_inodecache(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 */
befs_symlink_read_folio(struct file * unused,struct folio * folio)470 static int befs_symlink_read_folio(struct file *unused, struct folio *folio)
471 {
472 struct inode *inode = folio->mapping->host;
473 struct super_block *sb = inode->i_sb;
474 struct befs_inode_info *befs_ino = BEFS_I(inode);
475 befs_data_stream *data = &befs_ino->i_data.ds;
476 befs_off_t len = data->size;
477 char *link = folio_address(folio);
478 int err = -EIO;
479
480 if (len == 0 || len > PAGE_SIZE) {
481 befs_error(sb, "Long symlink with illegal length");
482 goto fail;
483 }
484 befs_debug(sb, "Follow long symlink");
485
486 if (befs_read_lsymlink(sb, data, link, len) != len) {
487 befs_error(sb, "Failed to read entire long symlink");
488 goto fail;
489 }
490 link[len - 1] = '\0';
491 err = 0;
492 fail:
493 folio_end_read(folio, err == 0);
494 return err;
495 }
496
497 /*
498 * UTF-8 to NLS charset convert routine
499 *
500 * Uses uni2char() / char2uni() rather than the nls tables directly
501 */
502 static int
befs_utf2nls(struct super_block * sb,const char * in,int in_len,char ** out,int * out_len)503 befs_utf2nls(struct super_block *sb, const char *in,
504 int in_len, char **out, int *out_len)
505 {
506 struct nls_table *nls = BEFS_SB(sb)->nls;
507 int i, o;
508 unicode_t uni;
509 int unilen, utflen;
510 char *result;
511 /* The utf8->nls conversion won't make the final nls string bigger
512 * than the utf one, but if the string is pure ascii they'll have the
513 * same width and an extra char is needed to save the additional \0
514 */
515 int maxlen = in_len + 1;
516
517 befs_debug(sb, "---> %s", __func__);
518
519 if (!nls) {
520 befs_error(sb, "%s called with no NLS table loaded", __func__);
521 return -EINVAL;
522 }
523
524 *out = result = kmalloc(maxlen, GFP_NOFS);
525 if (!*out)
526 return -ENOMEM;
527
528 for (i = o = 0; i < in_len; i += utflen, o += unilen) {
529
530 /* convert from UTF-8 to Unicode */
531 utflen = utf8_to_utf32(&in[i], in_len - i, &uni);
532 if (utflen < 0)
533 goto conv_err;
534
535 /* convert from Unicode to nls */
536 if (uni > MAX_WCHAR_T)
537 goto conv_err;
538 unilen = nls->uni2char(uni, &result[o], in_len - o);
539 if (unilen < 0)
540 goto conv_err;
541 }
542 result[o] = '\0';
543 *out_len = o;
544
545 befs_debug(sb, "<--- %s", __func__);
546
547 return o;
548
549 conv_err:
550 befs_error(sb, "Name using character set %s contains a character that "
551 "cannot be converted to unicode.", nls->charset);
552 befs_debug(sb, "<--- %s", __func__);
553 kfree(result);
554 return -EILSEQ;
555 }
556
557 /**
558 * befs_nls2utf - Convert NLS string to utf8 encodeing
559 * @sb: Superblock
560 * @in: Input string buffer in NLS format
561 * @in_len: Length of input string in bytes
562 * @out: The output string in UTF-8 format
563 * @out_len: Length of the output buffer
564 *
565 * Converts input string @in, which is in the format of the loaded NLS map,
566 * into a utf8 string.
567 *
568 * The destination string @out is allocated by this function and the caller is
569 * responsible for freeing it with kfree()
570 *
571 * On return, *@out_len is the length of @out in bytes.
572 *
573 * On success, the return value is the number of utf8 characters written to
574 * the output buffer @out.
575 *
576 * On Failure, a negative number coresponding to the error code is returned.
577 */
578
579 static int
befs_nls2utf(struct super_block * sb,const char * in,int in_len,char ** out,int * out_len)580 befs_nls2utf(struct super_block *sb, const char *in,
581 int in_len, char **out, int *out_len)
582 {
583 struct nls_table *nls = BEFS_SB(sb)->nls;
584 int i, o;
585 wchar_t uni;
586 int unilen, utflen;
587 char *result;
588 /*
589 * There are nls characters that will translate to 3-chars-wide UTF-8
590 * characters, an additional byte is needed to save the final \0
591 * in special cases
592 */
593 int maxlen = (3 * in_len) + 1;
594
595 befs_debug(sb, "---> %s\n", __func__);
596
597 if (!nls) {
598 befs_error(sb, "%s called with no NLS table loaded.",
599 __func__);
600 return -EINVAL;
601 }
602
603 *out = result = kmalloc(maxlen, GFP_NOFS);
604 if (!*out) {
605 *out_len = 0;
606 return -ENOMEM;
607 }
608
609 for (i = o = 0; i < in_len; i += unilen, o += utflen) {
610
611 /* convert from nls to unicode */
612 unilen = nls->char2uni(&in[i], in_len - i, &uni);
613 if (unilen < 0)
614 goto conv_err;
615
616 /* convert from unicode to UTF-8 */
617 utflen = utf32_to_utf8(uni, &result[o], 3);
618 if (utflen <= 0)
619 goto conv_err;
620 }
621
622 result[o] = '\0';
623 *out_len = o;
624
625 befs_debug(sb, "<--- %s", __func__);
626
627 return i;
628
629 conv_err:
630 befs_error(sb, "Name using character set %s contains a character that "
631 "cannot be converted to unicode.", nls->charset);
632 befs_debug(sb, "<--- %s", __func__);
633 kfree(result);
634 return -EILSEQ;
635 }
636
befs_nfs_get_inode(struct super_block * sb,uint64_t ino,uint32_t generation)637 static struct inode *befs_nfs_get_inode(struct super_block *sb, uint64_t ino,
638 uint32_t generation)
639 {
640 /* No need to handle i_generation */
641 return befs_iget(sb, ino);
642 }
643
644 /*
645 * Map a NFS file handle to a corresponding dentry
646 */
befs_fh_to_dentry(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)647 static struct dentry *befs_fh_to_dentry(struct super_block *sb,
648 struct fid *fid, int fh_len, int fh_type)
649 {
650 return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
651 befs_nfs_get_inode);
652 }
653
654 /*
655 * Find the parent for a file specified by NFS handle
656 */
befs_fh_to_parent(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)657 static struct dentry *befs_fh_to_parent(struct super_block *sb,
658 struct fid *fid, int fh_len, int fh_type)
659 {
660 return generic_fh_to_parent(sb, fid, fh_len, fh_type,
661 befs_nfs_get_inode);
662 }
663
befs_get_parent(struct dentry * child)664 static struct dentry *befs_get_parent(struct dentry *child)
665 {
666 struct inode *parent;
667 struct befs_inode_info *befs_ino = BEFS_I(d_inode(child));
668
669 parent = befs_iget(child->d_sb,
670 (unsigned long)befs_ino->i_parent.start);
671 return d_obtain_alias(parent);
672 }
673
674 enum {
675 Opt_uid, Opt_gid, Opt_charset, Opt_debug, Opt_err,
676 };
677
678 static const match_table_t befs_tokens = {
679 {Opt_uid, "uid=%d"},
680 {Opt_gid, "gid=%d"},
681 {Opt_charset, "iocharset=%s"},
682 {Opt_debug, "debug"},
683 {Opt_err, NULL}
684 };
685
686 static int
parse_options(char * options,struct befs_mount_options * opts)687 parse_options(char *options, struct befs_mount_options *opts)
688 {
689 char *p;
690 substring_t args[MAX_OPT_ARGS];
691 int option;
692 kuid_t uid;
693 kgid_t gid;
694
695 /* Initialize options */
696 opts->uid = GLOBAL_ROOT_UID;
697 opts->gid = GLOBAL_ROOT_GID;
698 opts->use_uid = 0;
699 opts->use_gid = 0;
700 opts->iocharset = NULL;
701 opts->debug = 0;
702
703 if (!options)
704 return 1;
705
706 while ((p = strsep(&options, ",")) != NULL) {
707 int token;
708
709 if (!*p)
710 continue;
711
712 token = match_token(p, befs_tokens, args);
713 switch (token) {
714 case Opt_uid:
715 if (match_int(&args[0], &option))
716 return 0;
717 uid = INVALID_UID;
718 if (option >= 0)
719 uid = make_kuid(current_user_ns(), option);
720 if (!uid_valid(uid)) {
721 pr_err("Invalid uid %d, "
722 "using default\n", option);
723 break;
724 }
725 opts->uid = uid;
726 opts->use_uid = 1;
727 break;
728 case Opt_gid:
729 if (match_int(&args[0], &option))
730 return 0;
731 gid = INVALID_GID;
732 if (option >= 0)
733 gid = make_kgid(current_user_ns(), option);
734 if (!gid_valid(gid)) {
735 pr_err("Invalid gid %d, "
736 "using default\n", option);
737 break;
738 }
739 opts->gid = gid;
740 opts->use_gid = 1;
741 break;
742 case Opt_charset:
743 kfree(opts->iocharset);
744 opts->iocharset = match_strdup(&args[0]);
745 if (!opts->iocharset) {
746 pr_err("allocation failure for "
747 "iocharset string\n");
748 return 0;
749 }
750 break;
751 case Opt_debug:
752 opts->debug = 1;
753 break;
754 default:
755 pr_err("Unrecognized mount option \"%s\" "
756 "or missing value\n", p);
757 return 0;
758 }
759 }
760 return 1;
761 }
762
befs_show_options(struct seq_file * m,struct dentry * root)763 static int befs_show_options(struct seq_file *m, struct dentry *root)
764 {
765 struct befs_sb_info *befs_sb = BEFS_SB(root->d_sb);
766 struct befs_mount_options *opts = &befs_sb->mount_opts;
767
768 if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
769 seq_printf(m, ",uid=%u",
770 from_kuid_munged(&init_user_ns, opts->uid));
771 if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
772 seq_printf(m, ",gid=%u",
773 from_kgid_munged(&init_user_ns, opts->gid));
774 if (opts->iocharset)
775 seq_printf(m, ",charset=%s", opts->iocharset);
776 if (opts->debug)
777 seq_puts(m, ",debug");
778 return 0;
779 }
780
781 /* This function has the responsibiltiy of getting the
782 * filesystem ready for unmounting.
783 * Basically, we free everything that we allocated in
784 * befs_read_inode
785 */
786 static void
befs_put_super(struct super_block * sb)787 befs_put_super(struct super_block *sb)
788 {
789 kfree(BEFS_SB(sb)->mount_opts.iocharset);
790 BEFS_SB(sb)->mount_opts.iocharset = NULL;
791 unload_nls(BEFS_SB(sb)->nls);
792 kfree(sb->s_fs_info);
793 sb->s_fs_info = NULL;
794 }
795
796 /* Allocate private field of the superblock, fill it.
797 *
798 * Finish filling the public superblock fields
799 * Make the root directory
800 * Load a set of NLS translations if needed.
801 */
802 static int
befs_fill_super(struct super_block * sb,void * data,int silent)803 befs_fill_super(struct super_block *sb, void *data, int silent)
804 {
805 struct buffer_head *bh;
806 struct befs_sb_info *befs_sb;
807 befs_super_block *disk_sb;
808 struct inode *root;
809 long ret = -EINVAL;
810 const unsigned long sb_block = 0;
811 const off_t x86_sb_off = 512;
812 int blocksize;
813
814 sb->s_fs_info = kzalloc(sizeof(*befs_sb), GFP_KERNEL);
815 if (sb->s_fs_info == NULL)
816 goto unacquire_none;
817
818 befs_sb = BEFS_SB(sb);
819
820 if (!parse_options((char *) data, &befs_sb->mount_opts)) {
821 if (!silent)
822 befs_error(sb, "cannot parse mount options");
823 goto unacquire_priv_sbp;
824 }
825
826 befs_debug(sb, "---> %s", __func__);
827
828 if (!sb_rdonly(sb)) {
829 befs_warning(sb,
830 "No write support. Marking filesystem read-only");
831 sb->s_flags |= SB_RDONLY;
832 }
833
834 /*
835 * Set dummy blocksize to read super block.
836 * Will be set to real fs blocksize later.
837 *
838 * Linux 2.4.10 and later refuse to read blocks smaller than
839 * the logical block size for the device. But we also need to read at
840 * least 1k to get the second 512 bytes of the volume.
841 */
842 blocksize = sb_min_blocksize(sb, 1024);
843 if (!blocksize) {
844 if (!silent)
845 befs_error(sb, "unable to set blocksize");
846 goto unacquire_priv_sbp;
847 }
848
849 bh = sb_bread(sb, sb_block);
850 if (!bh) {
851 if (!silent)
852 befs_error(sb, "unable to read superblock");
853 goto unacquire_priv_sbp;
854 }
855
856 /* account for offset of super block on x86 */
857 disk_sb = (befs_super_block *) bh->b_data;
858 if ((disk_sb->magic1 == BEFS_SUPER_MAGIC1_LE) ||
859 (disk_sb->magic1 == BEFS_SUPER_MAGIC1_BE)) {
860 befs_debug(sb, "Using PPC superblock location");
861 } else {
862 befs_debug(sb, "Using x86 superblock location");
863 disk_sb =
864 (befs_super_block *) ((void *) bh->b_data + x86_sb_off);
865 }
866
867 if ((befs_load_sb(sb, disk_sb) != BEFS_OK) ||
868 (befs_check_sb(sb) != BEFS_OK))
869 goto unacquire_bh;
870
871 befs_dump_super_block(sb, disk_sb);
872
873 brelse(bh);
874
875 if (befs_sb->num_blocks > ~((sector_t)0)) {
876 if (!silent)
877 befs_error(sb, "blocks count: %llu is larger than the host can use",
878 befs_sb->num_blocks);
879 goto unacquire_priv_sbp;
880 }
881
882 /*
883 * set up enough so that it can read an inode
884 * Fill in kernel superblock fields from private sb
885 */
886 sb->s_magic = BEFS_SUPER_MAGIC;
887 /* Set real blocksize of fs */
888 sb_set_blocksize(sb, (ulong) befs_sb->block_size);
889 sb->s_op = &befs_sops;
890 sb->s_export_op = &befs_export_operations;
891 sb->s_time_min = 0;
892 sb->s_time_max = 0xffffffffffffll;
893 root = befs_iget(sb, iaddr2blockno(sb, &(befs_sb->root_dir)));
894 if (IS_ERR(root)) {
895 ret = PTR_ERR(root);
896 goto unacquire_priv_sbp;
897 }
898 sb->s_root = d_make_root(root);
899 if (!sb->s_root) {
900 if (!silent)
901 befs_error(sb, "get root inode failed");
902 goto unacquire_priv_sbp;
903 }
904
905 /* load nls library */
906 if (befs_sb->mount_opts.iocharset) {
907 befs_debug(sb, "Loading nls: %s",
908 befs_sb->mount_opts.iocharset);
909 befs_sb->nls = load_nls(befs_sb->mount_opts.iocharset);
910 if (!befs_sb->nls) {
911 befs_warning(sb, "Cannot load nls %s"
912 " loading default nls",
913 befs_sb->mount_opts.iocharset);
914 befs_sb->nls = load_nls_default();
915 }
916 /* load default nls if none is specified in mount options */
917 } else {
918 befs_debug(sb, "Loading default nls");
919 befs_sb->nls = load_nls_default();
920 }
921
922 return 0;
923
924 unacquire_bh:
925 brelse(bh);
926
927 unacquire_priv_sbp:
928 kfree(befs_sb->mount_opts.iocharset);
929 kfree(sb->s_fs_info);
930 sb->s_fs_info = NULL;
931
932 unacquire_none:
933 return ret;
934 }
935
936 static int
befs_remount(struct super_block * sb,int * flags,char * data)937 befs_remount(struct super_block *sb, int *flags, char *data)
938 {
939 sync_filesystem(sb);
940 if (!(*flags & SB_RDONLY))
941 return -EINVAL;
942 return 0;
943 }
944
945 static int
befs_statfs(struct dentry * dentry,struct kstatfs * buf)946 befs_statfs(struct dentry *dentry, struct kstatfs *buf)
947 {
948 struct super_block *sb = dentry->d_sb;
949 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
950
951 befs_debug(sb, "---> %s", __func__);
952
953 buf->f_type = BEFS_SUPER_MAGIC;
954 buf->f_bsize = sb->s_blocksize;
955 buf->f_blocks = BEFS_SB(sb)->num_blocks;
956 buf->f_bfree = BEFS_SB(sb)->num_blocks - BEFS_SB(sb)->used_blocks;
957 buf->f_bavail = buf->f_bfree;
958 buf->f_files = 0; /* UNKNOWN */
959 buf->f_ffree = 0; /* UNKNOWN */
960 buf->f_fsid = u64_to_fsid(id);
961 buf->f_namelen = BEFS_NAME_LEN;
962
963 befs_debug(sb, "<--- %s", __func__);
964
965 return 0;
966 }
967
968 static struct dentry *
befs_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * data)969 befs_mount(struct file_system_type *fs_type, int flags, const char *dev_name,
970 void *data)
971 {
972 return mount_bdev(fs_type, flags, dev_name, data, befs_fill_super);
973 }
974
975 static struct file_system_type befs_fs_type = {
976 .owner = THIS_MODULE,
977 .name = "befs",
978 .mount = befs_mount,
979 .kill_sb = kill_block_super,
980 .fs_flags = FS_REQUIRES_DEV,
981 };
982 MODULE_ALIAS_FS("befs");
983
984 static int __init
init_befs_fs(void)985 init_befs_fs(void)
986 {
987 int err;
988
989 pr_info("version: %s\n", BEFS_VERSION);
990
991 err = befs_init_inodecache();
992 if (err)
993 goto unacquire_none;
994
995 err = register_filesystem(&befs_fs_type);
996 if (err)
997 goto unacquire_inodecache;
998
999 return 0;
1000
1001 unacquire_inodecache:
1002 befs_destroy_inodecache();
1003
1004 unacquire_none:
1005 return err;
1006 }
1007
1008 static void __exit
exit_befs_fs(void)1009 exit_befs_fs(void)
1010 {
1011 befs_destroy_inodecache();
1012
1013 unregister_filesystem(&befs_fs_type);
1014 }
1015
1016 /*
1017 * Macros that typecheck the init and exit functions,
1018 * ensures that they are called at init and cleanup,
1019 * and eliminates warnings about unused functions.
1020 */
1021 module_init(init_befs_fs)
1022 module_exit(exit_befs_fs)
1023