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 .fh_to_dentry = befs_fh_to_dentry,
100 .fh_to_parent = befs_fh_to_parent,
101 .get_parent = befs_get_parent,
102 };
103
104 /*
105 * Called by generic_file_read() to read a folio of data
106 *
107 * In turn, simply calls a generic block read function and
108 * passes it the address of befs_get_block, for mapping file
109 * positions to disk blocks.
110 */
befs_read_folio(struct file * file,struct folio * folio)111 static int befs_read_folio(struct file *file, struct folio *folio)
112 {
113 return block_read_full_folio(folio, befs_get_block);
114 }
115
116 static sector_t
befs_bmap(struct address_space * mapping,sector_t block)117 befs_bmap(struct address_space *mapping, sector_t block)
118 {
119 return generic_block_bmap(mapping, block, befs_get_block);
120 }
121
122 /*
123 * Generic function to map a file position (block) to a
124 * disk offset (passed back in bh_result).
125 *
126 * Used by many higher level functions.
127 *
128 * Calls befs_fblock2brun() in datastream.c to do the real work.
129 */
130
131 static int
befs_get_block(struct inode * inode,sector_t block,struct buffer_head * bh_result,int create)132 befs_get_block(struct inode *inode, sector_t block,
133 struct buffer_head *bh_result, int create)
134 {
135 struct super_block *sb = inode->i_sb;
136 befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
137 befs_block_run run = BAD_IADDR;
138 int res;
139 ulong disk_off;
140
141 befs_debug(sb, "---> befs_get_block() for inode %lu, block %ld",
142 (unsigned long)inode->i_ino, (long)block);
143 if (create) {
144 befs_error(sb, "befs_get_block() was asked to write to "
145 "block %ld in inode %lu", (long)block,
146 (unsigned long)inode->i_ino);
147 return -EPERM;
148 }
149
150 res = befs_fblock2brun(sb, ds, block, &run);
151 if (res != BEFS_OK) {
152 befs_error(sb,
153 "<--- %s for inode %lu, block %ld ERROR",
154 __func__, (unsigned long)inode->i_ino,
155 (long)block);
156 return -EFBIG;
157 }
158
159 disk_off = (ulong) iaddr2blockno(sb, &run);
160
161 map_bh(bh_result, inode->i_sb, disk_off);
162
163 befs_debug(sb, "<--- %s for inode %lu, block %ld, disk address %lu",
164 __func__, (unsigned long)inode->i_ino, (long)block,
165 (unsigned long)disk_off);
166
167 return 0;
168 }
169
170 static struct dentry *
befs_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)171 befs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
172 {
173 struct inode *inode;
174 struct super_block *sb = dir->i_sb;
175 const befs_data_stream *ds = &BEFS_I(dir)->i_data.ds;
176 befs_off_t offset;
177 int ret;
178 int utfnamelen;
179 char *utfname;
180 const char *name = dentry->d_name.name;
181
182 befs_debug(sb, "---> %s name %pd inode %ld", __func__,
183 dentry, dir->i_ino);
184
185 /* Convert to UTF-8 */
186 if (BEFS_SB(sb)->nls) {
187 ret =
188 befs_nls2utf(sb, name, strlen(name), &utfname, &utfnamelen);
189 if (ret < 0) {
190 befs_debug(sb, "<--- %s ERROR", __func__);
191 return ERR_PTR(ret);
192 }
193 ret = befs_btree_find(sb, ds, utfname, &offset);
194 kfree(utfname);
195
196 } else {
197 ret = befs_btree_find(sb, ds, name, &offset);
198 }
199
200 if (ret == BEFS_BT_NOT_FOUND) {
201 befs_debug(sb, "<--- %s %pd not found", __func__, dentry);
202 inode = NULL;
203 } else if (ret != BEFS_OK || offset == 0) {
204 befs_error(sb, "<--- %s Error", __func__);
205 inode = ERR_PTR(-ENODATA);
206 } else {
207 inode = befs_iget(dir->i_sb, (ino_t) offset);
208 }
209 befs_debug(sb, "<--- %s", __func__);
210
211 return d_splice_alias(inode, dentry);
212 }
213
214 static int
befs_readdir(struct file * file,struct dir_context * ctx)215 befs_readdir(struct file *file, struct dir_context *ctx)
216 {
217 struct inode *inode = file_inode(file);
218 struct super_block *sb = inode->i_sb;
219 const befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
220 befs_off_t value;
221 int result;
222 size_t keysize;
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 while (1) {
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 /* Convert to NLS */
248 if (BEFS_SB(sb)->nls) {
249 char *nlsname;
250 int nlsnamelen;
251
252 result =
253 befs_utf2nls(sb, keybuf, keysize, &nlsname,
254 &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, DT_UNKNOWN)) {
261 kfree(nlsname);
262 return 0;
263 }
264 kfree(nlsname);
265 } else {
266 if (!dir_emit(ctx, keybuf, keysize,
267 (ino_t) value, DT_UNKNOWN))
268 return 0;
269 }
270 ctx->pos++;
271 }
272 }
273
274 static struct inode *
befs_alloc_inode(struct super_block * sb)275 befs_alloc_inode(struct super_block *sb)
276 {
277 struct befs_inode_info *bi;
278
279 bi = alloc_inode_sb(sb, befs_inode_cachep, GFP_KERNEL);
280 if (!bi)
281 return NULL;
282 return &bi->vfs_inode;
283 }
284
befs_free_inode(struct inode * inode)285 static void befs_free_inode(struct inode *inode)
286 {
287 kmem_cache_free(befs_inode_cachep, BEFS_I(inode));
288 }
289
init_once(void * foo)290 static void init_once(void *foo)
291 {
292 struct befs_inode_info *bi = (struct befs_inode_info *) foo;
293
294 inode_init_once(&bi->vfs_inode);
295 }
296
befs_iget(struct super_block * sb,unsigned long ino)297 static struct inode *befs_iget(struct super_block *sb, unsigned long ino)
298 {
299 struct buffer_head *bh;
300 befs_inode *raw_inode;
301 struct befs_sb_info *befs_sb = BEFS_SB(sb);
302 struct befs_inode_info *befs_ino;
303 struct inode *inode;
304
305 befs_debug(sb, "---> %s inode = %lu", __func__, ino);
306
307 inode = iget_locked(sb, ino);
308 if (!inode)
309 return ERR_PTR(-ENOMEM);
310 if (!(inode->i_state & I_NEW))
311 return inode;
312
313 befs_ino = BEFS_I(inode);
314
315 /* convert from vfs's inode number to befs's inode number */
316 befs_ino->i_inode_num = blockno2iaddr(sb, inode->i_ino);
317
318 befs_debug(sb, " real inode number [%u, %hu, %hu]",
319 befs_ino->i_inode_num.allocation_group,
320 befs_ino->i_inode_num.start, befs_ino->i_inode_num.len);
321
322 bh = sb_bread(sb, inode->i_ino);
323 if (!bh) {
324 befs_error(sb, "unable to read inode block - "
325 "inode = %lu", inode->i_ino);
326 goto unacquire_none;
327 }
328
329 raw_inode = (befs_inode *) bh->b_data;
330
331 befs_dump_inode(sb, raw_inode);
332
333 if (befs_check_inode(sb, raw_inode, inode->i_ino) != BEFS_OK) {
334 befs_error(sb, "Bad inode: %lu", inode->i_ino);
335 goto unacquire_bh;
336 }
337
338 inode->i_mode = (umode_t) fs32_to_cpu(sb, raw_inode->mode);
339
340 /*
341 * set uid and gid. But since current BeOS is single user OS, so
342 * you can change by "uid" or "gid" options.
343 */
344
345 inode->i_uid = befs_sb->mount_opts.use_uid ?
346 befs_sb->mount_opts.uid :
347 make_kuid(&init_user_ns, fs32_to_cpu(sb, raw_inode->uid));
348 inode->i_gid = befs_sb->mount_opts.use_gid ?
349 befs_sb->mount_opts.gid :
350 make_kgid(&init_user_ns, fs32_to_cpu(sb, raw_inode->gid));
351
352 set_nlink(inode, 1);
353
354 /*
355 * BEFS's time is 64 bits, but current VFS is 32 bits...
356 * BEFS don't have access time. Nor inode change time. VFS
357 * doesn't have creation time.
358 * Also, the lower 16 bits of the last_modified_time and
359 * create_time are just a counter to help ensure uniqueness
360 * for indexing purposes. (PFD, page 54)
361 */
362
363 inode->i_mtime.tv_sec =
364 fs64_to_cpu(sb, raw_inode->last_modified_time) >> 16;
365 inode->i_mtime.tv_nsec = 0; /* lower 16 bits are not a time */
366 inode_set_ctime_to_ts(inode, inode->i_mtime);
367 inode->i_atime = inode->i_mtime;
368
369 befs_ino->i_inode_num = fsrun_to_cpu(sb, raw_inode->inode_num);
370 befs_ino->i_parent = fsrun_to_cpu(sb, raw_inode->parent);
371 befs_ino->i_attribute = fsrun_to_cpu(sb, raw_inode->attributes);
372 befs_ino->i_flags = fs32_to_cpu(sb, raw_inode->flags);
373
374 if (S_ISLNK(inode->i_mode) && !(befs_ino->i_flags & BEFS_LONG_SYMLINK)){
375 inode->i_size = 0;
376 inode->i_blocks = befs_sb->block_size / VFS_BLOCK_SIZE;
377 strscpy(befs_ino->i_data.symlink, raw_inode->data.symlink,
378 BEFS_SYMLINK_LEN);
379 } else {
380 int num_blks;
381
382 befs_ino->i_data.ds =
383 fsds_to_cpu(sb, &raw_inode->data.datastream);
384
385 num_blks = befs_count_blocks(sb, &befs_ino->i_data.ds);
386 inode->i_blocks =
387 num_blks * (befs_sb->block_size / VFS_BLOCK_SIZE);
388 inode->i_size = befs_ino->i_data.ds.size;
389 }
390
391 inode->i_mapping->a_ops = &befs_aops;
392
393 if (S_ISREG(inode->i_mode)) {
394 inode->i_fop = &generic_ro_fops;
395 } else if (S_ISDIR(inode->i_mode)) {
396 inode->i_op = &befs_dir_inode_operations;
397 inode->i_fop = &befs_dir_operations;
398 } else if (S_ISLNK(inode->i_mode)) {
399 if (befs_ino->i_flags & BEFS_LONG_SYMLINK) {
400 inode->i_op = &page_symlink_inode_operations;
401 inode_nohighmem(inode);
402 inode->i_mapping->a_ops = &befs_symlink_aops;
403 } else {
404 inode->i_link = befs_ino->i_data.symlink;
405 inode->i_op = &simple_symlink_inode_operations;
406 }
407 } else {
408 befs_error(sb, "Inode %lu is not a regular file, "
409 "directory or symlink. THAT IS WRONG! BeFS has no "
410 "on disk special files", inode->i_ino);
411 goto unacquire_bh;
412 }
413
414 brelse(bh);
415 befs_debug(sb, "<--- %s", __func__);
416 unlock_new_inode(inode);
417 return inode;
418
419 unacquire_bh:
420 brelse(bh);
421
422 unacquire_none:
423 iget_failed(inode);
424 befs_debug(sb, "<--- %s - Bad inode", __func__);
425 return ERR_PTR(-EIO);
426 }
427
428 /* Initialize the inode cache. Called at fs setup.
429 *
430 * Taken from NFS implementation by Al Viro.
431 */
432 static int __init
befs_init_inodecache(void)433 befs_init_inodecache(void)
434 {
435 befs_inode_cachep = kmem_cache_create_usercopy("befs_inode_cache",
436 sizeof(struct befs_inode_info), 0,
437 (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
438 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
479 if (len == 0 || len > PAGE_SIZE) {
480 befs_error(sb, "Long symlink with illegal length");
481 goto fail;
482 }
483 befs_debug(sb, "Follow long symlink");
484
485 if (befs_read_lsymlink(sb, data, link, len) != len) {
486 befs_error(sb, "Failed to read entire long symlink");
487 goto fail;
488 }
489 link[len - 1] = '\0';
490 folio_mark_uptodate(folio);
491 folio_unlock(folio);
492 return 0;
493 fail:
494 folio_set_error(folio);
495 folio_unlock(folio);
496 return -EIO;
497 }
498
499 /*
500 * UTF-8 to NLS charset convert routine
501 *
502 * Uses uni2char() / char2uni() rather than the nls tables directly
503 */
504 static int
befs_utf2nls(struct super_block * sb,const char * in,int in_len,char ** out,int * out_len)505 befs_utf2nls(struct super_block *sb, const char *in,
506 int in_len, char **out, int *out_len)
507 {
508 struct nls_table *nls = BEFS_SB(sb)->nls;
509 int i, o;
510 unicode_t uni;
511 int unilen, utflen;
512 char *result;
513 /* The utf8->nls conversion won't make the final nls string bigger
514 * than the utf one, but if the string is pure ascii they'll have the
515 * same width and an extra char is needed to save the additional \0
516 */
517 int maxlen = in_len + 1;
518
519 befs_debug(sb, "---> %s", __func__);
520
521 if (!nls) {
522 befs_error(sb, "%s called with no NLS table loaded", __func__);
523 return -EINVAL;
524 }
525
526 *out = result = kmalloc(maxlen, GFP_NOFS);
527 if (!*out)
528 return -ENOMEM;
529
530 for (i = o = 0; i < in_len; i += utflen, o += unilen) {
531
532 /* convert from UTF-8 to Unicode */
533 utflen = utf8_to_utf32(&in[i], in_len - i, &uni);
534 if (utflen < 0)
535 goto conv_err;
536
537 /* convert from Unicode to nls */
538 if (uni > MAX_WCHAR_T)
539 goto conv_err;
540 unilen = nls->uni2char(uni, &result[o], in_len - o);
541 if (unilen < 0)
542 goto conv_err;
543 }
544 result[o] = '\0';
545 *out_len = o;
546
547 befs_debug(sb, "<--- %s", __func__);
548
549 return o;
550
551 conv_err:
552 befs_error(sb, "Name using character set %s contains a character that "
553 "cannot be converted to unicode.", nls->charset);
554 befs_debug(sb, "<--- %s", __func__);
555 kfree(result);
556 return -EILSEQ;
557 }
558
559 /**
560 * befs_nls2utf - Convert NLS string to utf8 encodeing
561 * @sb: Superblock
562 * @in: Input string buffer in NLS format
563 * @in_len: Length of input string in bytes
564 * @out: The output string in UTF-8 format
565 * @out_len: Length of the output buffer
566 *
567 * Converts input string @in, which is in the format of the loaded NLS map,
568 * into a utf8 string.
569 *
570 * The destination string @out is allocated by this function and the caller is
571 * responsible for freeing it with kfree()
572 *
573 * On return, *@out_len is the length of @out in bytes.
574 *
575 * On success, the return value is the number of utf8 characters written to
576 * the output buffer @out.
577 *
578 * On Failure, a negative number coresponding to the error code is returned.
579 */
580
581 static int
befs_nls2utf(struct super_block * sb,const char * in,int in_len,char ** out,int * out_len)582 befs_nls2utf(struct super_block *sb, const char *in,
583 int in_len, char **out, int *out_len)
584 {
585 struct nls_table *nls = BEFS_SB(sb)->nls;
586 int i, o;
587 wchar_t uni;
588 int unilen, utflen;
589 char *result;
590 /*
591 * There are nls characters that will translate to 3-chars-wide UTF-8
592 * characters, an additional byte is needed to save the final \0
593 * in special cases
594 */
595 int maxlen = (3 * in_len) + 1;
596
597 befs_debug(sb, "---> %s\n", __func__);
598
599 if (!nls) {
600 befs_error(sb, "%s called with no NLS table loaded.",
601 __func__);
602 return -EINVAL;
603 }
604
605 *out = result = kmalloc(maxlen, GFP_NOFS);
606 if (!*out) {
607 *out_len = 0;
608 return -ENOMEM;
609 }
610
611 for (i = o = 0; i < in_len; i += unilen, o += utflen) {
612
613 /* convert from nls to unicode */
614 unilen = nls->char2uni(&in[i], in_len - i, &uni);
615 if (unilen < 0)
616 goto conv_err;
617
618 /* convert from unicode to UTF-8 */
619 utflen = utf32_to_utf8(uni, &result[o], 3);
620 if (utflen <= 0)
621 goto conv_err;
622 }
623
624 result[o] = '\0';
625 *out_len = o;
626
627 befs_debug(sb, "<--- %s", __func__);
628
629 return i;
630
631 conv_err:
632 befs_error(sb, "Name using character set %s contains a character that "
633 "cannot be converted to unicode.", nls->charset);
634 befs_debug(sb, "<--- %s", __func__);
635 kfree(result);
636 return -EILSEQ;
637 }
638
befs_nfs_get_inode(struct super_block * sb,uint64_t ino,uint32_t generation)639 static struct inode *befs_nfs_get_inode(struct super_block *sb, uint64_t ino,
640 uint32_t generation)
641 {
642 /* No need to handle i_generation */
643 return befs_iget(sb, ino);
644 }
645
646 /*
647 * Map a NFS file handle to a corresponding dentry
648 */
befs_fh_to_dentry(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)649 static struct dentry *befs_fh_to_dentry(struct super_block *sb,
650 struct fid *fid, int fh_len, int fh_type)
651 {
652 return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
653 befs_nfs_get_inode);
654 }
655
656 /*
657 * Find the parent for a file specified by NFS handle
658 */
befs_fh_to_parent(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)659 static struct dentry *befs_fh_to_parent(struct super_block *sb,
660 struct fid *fid, int fh_len, int fh_type)
661 {
662 return generic_fh_to_parent(sb, fid, fh_len, fh_type,
663 befs_nfs_get_inode);
664 }
665
befs_get_parent(struct dentry * child)666 static struct dentry *befs_get_parent(struct dentry *child)
667 {
668 struct inode *parent;
669 struct befs_inode_info *befs_ino = BEFS_I(d_inode(child));
670
671 parent = befs_iget(child->d_sb,
672 (unsigned long)befs_ino->i_parent.start);
673 if (IS_ERR(parent))
674 return ERR_CAST(parent);
675
676 return d_obtain_alias(parent);
677 }
678
679 enum {
680 Opt_uid, Opt_gid, Opt_charset, Opt_debug, Opt_err,
681 };
682
683 static const match_table_t befs_tokens = {
684 {Opt_uid, "uid=%d"},
685 {Opt_gid, "gid=%d"},
686 {Opt_charset, "iocharset=%s"},
687 {Opt_debug, "debug"},
688 {Opt_err, NULL}
689 };
690
691 static int
parse_options(char * options,struct befs_mount_options * opts)692 parse_options(char *options, struct befs_mount_options *opts)
693 {
694 char *p;
695 substring_t args[MAX_OPT_ARGS];
696 int option;
697 kuid_t uid;
698 kgid_t gid;
699
700 /* Initialize options */
701 opts->uid = GLOBAL_ROOT_UID;
702 opts->gid = GLOBAL_ROOT_GID;
703 opts->use_uid = 0;
704 opts->use_gid = 0;
705 opts->iocharset = NULL;
706 opts->debug = 0;
707
708 if (!options)
709 return 1;
710
711 while ((p = strsep(&options, ",")) != NULL) {
712 int token;
713
714 if (!*p)
715 continue;
716
717 token = match_token(p, befs_tokens, args);
718 switch (token) {
719 case Opt_uid:
720 if (match_int(&args[0], &option))
721 return 0;
722 uid = INVALID_UID;
723 if (option >= 0)
724 uid = make_kuid(current_user_ns(), option);
725 if (!uid_valid(uid)) {
726 pr_err("Invalid uid %d, "
727 "using default\n", option);
728 break;
729 }
730 opts->uid = uid;
731 opts->use_uid = 1;
732 break;
733 case Opt_gid:
734 if (match_int(&args[0], &option))
735 return 0;
736 gid = INVALID_GID;
737 if (option >= 0)
738 gid = make_kgid(current_user_ns(), option);
739 if (!gid_valid(gid)) {
740 pr_err("Invalid gid %d, "
741 "using default\n", option);
742 break;
743 }
744 opts->gid = gid;
745 opts->use_gid = 1;
746 break;
747 case Opt_charset:
748 kfree(opts->iocharset);
749 opts->iocharset = match_strdup(&args[0]);
750 if (!opts->iocharset) {
751 pr_err("allocation failure for "
752 "iocharset string\n");
753 return 0;
754 }
755 break;
756 case Opt_debug:
757 opts->debug = 1;
758 break;
759 default:
760 pr_err("Unrecognized mount option \"%s\" "
761 "or missing value\n", p);
762 return 0;
763 }
764 }
765 return 1;
766 }
767
befs_show_options(struct seq_file * m,struct dentry * root)768 static int befs_show_options(struct seq_file *m, struct dentry *root)
769 {
770 struct befs_sb_info *befs_sb = BEFS_SB(root->d_sb);
771 struct befs_mount_options *opts = &befs_sb->mount_opts;
772
773 if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
774 seq_printf(m, ",uid=%u",
775 from_kuid_munged(&init_user_ns, opts->uid));
776 if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
777 seq_printf(m, ",gid=%u",
778 from_kgid_munged(&init_user_ns, opts->gid));
779 if (opts->iocharset)
780 seq_printf(m, ",charset=%s", opts->iocharset);
781 if (opts->debug)
782 seq_puts(m, ",debug");
783 return 0;
784 }
785
786 /* This function has the responsibiltiy of getting the
787 * filesystem ready for unmounting.
788 * Basically, we free everything that we allocated in
789 * befs_read_inode
790 */
791 static void
befs_put_super(struct super_block * sb)792 befs_put_super(struct super_block *sb)
793 {
794 kfree(BEFS_SB(sb)->mount_opts.iocharset);
795 BEFS_SB(sb)->mount_opts.iocharset = NULL;
796 unload_nls(BEFS_SB(sb)->nls);
797 kfree(sb->s_fs_info);
798 sb->s_fs_info = NULL;
799 }
800
801 /* Allocate private field of the superblock, fill it.
802 *
803 * Finish filling the public superblock fields
804 * Make the root directory
805 * Load a set of NLS translations if needed.
806 */
807 static int
befs_fill_super(struct super_block * sb,void * data,int silent)808 befs_fill_super(struct super_block *sb, void *data, int silent)
809 {
810 struct buffer_head *bh;
811 struct befs_sb_info *befs_sb;
812 befs_super_block *disk_sb;
813 struct inode *root;
814 long ret = -EINVAL;
815 const unsigned long sb_block = 0;
816 const off_t x86_sb_off = 512;
817 int blocksize;
818
819 sb->s_fs_info = kzalloc(sizeof(*befs_sb), GFP_KERNEL);
820 if (sb->s_fs_info == NULL)
821 goto unacquire_none;
822
823 befs_sb = BEFS_SB(sb);
824
825 if (!parse_options((char *) data, &befs_sb->mount_opts)) {
826 if (!silent)
827 befs_error(sb, "cannot parse mount options");
828 goto unacquire_priv_sbp;
829 }
830
831 befs_debug(sb, "---> %s", __func__);
832
833 if (!sb_rdonly(sb)) {
834 befs_warning(sb,
835 "No write support. Marking filesystem read-only");
836 sb->s_flags |= SB_RDONLY;
837 }
838
839 /*
840 * Set dummy blocksize to read super block.
841 * Will be set to real fs blocksize later.
842 *
843 * Linux 2.4.10 and later refuse to read blocks smaller than
844 * the logical block size for the device. But we also need to read at
845 * least 1k to get the second 512 bytes of the volume.
846 */
847 blocksize = sb_min_blocksize(sb, 1024);
848 if (!blocksize) {
849 if (!silent)
850 befs_error(sb, "unable to set blocksize");
851 goto unacquire_priv_sbp;
852 }
853
854 bh = sb_bread(sb, sb_block);
855 if (!bh) {
856 if (!silent)
857 befs_error(sb, "unable to read superblock");
858 goto unacquire_priv_sbp;
859 }
860
861 /* account for offset of super block on x86 */
862 disk_sb = (befs_super_block *) bh->b_data;
863 if ((disk_sb->magic1 == BEFS_SUPER_MAGIC1_LE) ||
864 (disk_sb->magic1 == BEFS_SUPER_MAGIC1_BE)) {
865 befs_debug(sb, "Using PPC superblock location");
866 } else {
867 befs_debug(sb, "Using x86 superblock location");
868 disk_sb =
869 (befs_super_block *) ((void *) bh->b_data + x86_sb_off);
870 }
871
872 if ((befs_load_sb(sb, disk_sb) != BEFS_OK) ||
873 (befs_check_sb(sb) != BEFS_OK))
874 goto unacquire_bh;
875
876 befs_dump_super_block(sb, disk_sb);
877
878 brelse(bh);
879
880 if (befs_sb->num_blocks > ~((sector_t)0)) {
881 if (!silent)
882 befs_error(sb, "blocks count: %llu is larger than the host can use",
883 befs_sb->num_blocks);
884 goto unacquire_priv_sbp;
885 }
886
887 /*
888 * set up enough so that it can read an inode
889 * Fill in kernel superblock fields from private sb
890 */
891 sb->s_magic = BEFS_SUPER_MAGIC;
892 /* Set real blocksize of fs */
893 sb_set_blocksize(sb, (ulong) befs_sb->block_size);
894 sb->s_op = &befs_sops;
895 sb->s_export_op = &befs_export_operations;
896 sb->s_time_min = 0;
897 sb->s_time_max = 0xffffffffffffll;
898 root = befs_iget(sb, iaddr2blockno(sb, &(befs_sb->root_dir)));
899 if (IS_ERR(root)) {
900 ret = PTR_ERR(root);
901 goto unacquire_priv_sbp;
902 }
903 sb->s_root = d_make_root(root);
904 if (!sb->s_root) {
905 if (!silent)
906 befs_error(sb, "get root inode failed");
907 goto unacquire_priv_sbp;
908 }
909
910 /* load nls library */
911 if (befs_sb->mount_opts.iocharset) {
912 befs_debug(sb, "Loading nls: %s",
913 befs_sb->mount_opts.iocharset);
914 befs_sb->nls = load_nls(befs_sb->mount_opts.iocharset);
915 if (!befs_sb->nls) {
916 befs_warning(sb, "Cannot load nls %s"
917 " loading default nls",
918 befs_sb->mount_opts.iocharset);
919 befs_sb->nls = load_nls_default();
920 }
921 /* load default nls if none is specified in mount options */
922 } else {
923 befs_debug(sb, "Loading default nls");
924 befs_sb->nls = load_nls_default();
925 }
926
927 return 0;
928
929 unacquire_bh:
930 brelse(bh);
931
932 unacquire_priv_sbp:
933 kfree(befs_sb->mount_opts.iocharset);
934 kfree(sb->s_fs_info);
935 sb->s_fs_info = NULL;
936
937 unacquire_none:
938 return ret;
939 }
940
941 static int
befs_remount(struct super_block * sb,int * flags,char * data)942 befs_remount(struct super_block *sb, int *flags, char *data)
943 {
944 sync_filesystem(sb);
945 if (!(*flags & SB_RDONLY))
946 return -EINVAL;
947 return 0;
948 }
949
950 static int
befs_statfs(struct dentry * dentry,struct kstatfs * buf)951 befs_statfs(struct dentry *dentry, struct kstatfs *buf)
952 {
953 struct super_block *sb = dentry->d_sb;
954 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
955
956 befs_debug(sb, "---> %s", __func__);
957
958 buf->f_type = BEFS_SUPER_MAGIC;
959 buf->f_bsize = sb->s_blocksize;
960 buf->f_blocks = BEFS_SB(sb)->num_blocks;
961 buf->f_bfree = BEFS_SB(sb)->num_blocks - BEFS_SB(sb)->used_blocks;
962 buf->f_bavail = buf->f_bfree;
963 buf->f_files = 0; /* UNKNOWN */
964 buf->f_ffree = 0; /* UNKNOWN */
965 buf->f_fsid = u64_to_fsid(id);
966 buf->f_namelen = BEFS_NAME_LEN;
967
968 befs_debug(sb, "<--- %s", __func__);
969
970 return 0;
971 }
972
973 static struct dentry *
befs_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * data)974 befs_mount(struct file_system_type *fs_type, int flags, const char *dev_name,
975 void *data)
976 {
977 return mount_bdev(fs_type, flags, dev_name, data, befs_fill_super);
978 }
979
980 static struct file_system_type befs_fs_type = {
981 .owner = THIS_MODULE,
982 .name = "befs",
983 .mount = befs_mount,
984 .kill_sb = kill_block_super,
985 .fs_flags = FS_REQUIRES_DEV,
986 };
987 MODULE_ALIAS_FS("befs");
988
989 static int __init
init_befs_fs(void)990 init_befs_fs(void)
991 {
992 int err;
993
994 pr_info("version: %s\n", BEFS_VERSION);
995
996 err = befs_init_inodecache();
997 if (err)
998 goto unacquire_none;
999
1000 err = register_filesystem(&befs_fs_type);
1001 if (err)
1002 goto unacquire_inodecache;
1003
1004 return 0;
1005
1006 unacquire_inodecache:
1007 befs_destroy_inodecache();
1008
1009 unacquire_none:
1010 return err;
1011 }
1012
1013 static void __exit
exit_befs_fs(void)1014 exit_befs_fs(void)
1015 {
1016 befs_destroy_inodecache();
1017
1018 unregister_filesystem(&befs_fs_type);
1019 }
1020
1021 /*
1022 * Macros that typecheck the init and exit functions,
1023 * ensures that they are called at init and cleanup,
1024 * and eliminates warnings about unused functions.
1025 */
1026 module_init(init_befs_fs)
1027 module_exit(exit_befs_fs)
1028