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 MODULE_IMPORT_NS(ANDROID_GKI_VFS_EXPORT_ONLY);
38
39 /* The units the vfs expects inode->i_blocks to be in */
40 #define VFS_BLOCK_SIZE 512
41
42 static int befs_readdir(struct file *, struct dir_context *);
43 static int befs_get_block(struct inode *, sector_t, struct buffer_head *, int);
44 static int befs_readpage(struct file *file, struct page *page);
45 static sector_t befs_bmap(struct address_space *mapping, sector_t block);
46 static struct dentry *befs_lookup(struct inode *, struct dentry *,
47 unsigned int);
48 static struct inode *befs_iget(struct super_block *, unsigned long);
49 static struct inode *befs_alloc_inode(struct super_block *sb);
50 static void befs_free_inode(struct inode *inode);
51 static void befs_destroy_inodecache(void);
52 static int befs_symlink_readpage(struct file *, struct page *);
53 static int befs_utf2nls(struct super_block *sb, const char *in, int in_len,
54 char **out, int *out_len);
55 static int befs_nls2utf(struct super_block *sb, const char *in, int in_len,
56 char **out, int *out_len);
57 static void befs_put_super(struct super_block *);
58 static int befs_remount(struct super_block *, int *, char *);
59 static int befs_statfs(struct dentry *, struct kstatfs *);
60 static int befs_show_options(struct seq_file *, struct dentry *);
61 static int parse_options(char *, struct befs_mount_options *);
62 static struct dentry *befs_fh_to_dentry(struct super_block *sb,
63 struct fid *fid, int fh_len, int fh_type);
64 static struct dentry *befs_fh_to_parent(struct super_block *sb,
65 struct fid *fid, int fh_len, int fh_type);
66 static struct dentry *befs_get_parent(struct dentry *child);
67
68 static const struct super_operations befs_sops = {
69 .alloc_inode = befs_alloc_inode, /* allocate a new inode */
70 .free_inode = befs_free_inode, /* deallocate an inode */
71 .put_super = befs_put_super, /* uninit super */
72 .statfs = befs_statfs, /* statfs */
73 .remount_fs = befs_remount,
74 .show_options = befs_show_options,
75 };
76
77 /* slab cache for befs_inode_info objects */
78 static struct kmem_cache *befs_inode_cachep;
79
80 static const struct file_operations befs_dir_operations = {
81 .read = generic_read_dir,
82 .iterate_shared = befs_readdir,
83 .llseek = generic_file_llseek,
84 };
85
86 static const struct inode_operations befs_dir_inode_operations = {
87 .lookup = befs_lookup,
88 };
89
90 static const struct address_space_operations befs_aops = {
91 .readpage = befs_readpage,
92 .bmap = befs_bmap,
93 };
94
95 static const struct address_space_operations befs_symlink_aops = {
96 .readpage = befs_symlink_readpage,
97 };
98
99 static const struct export_operations befs_export_operations = {
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 page 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 */
112 static int
befs_readpage(struct file * file,struct page * page)113 befs_readpage(struct file *file, struct page *page)
114 {
115 return block_read_full_page(page, befs_get_block);
116 }
117
118 static sector_t
befs_bmap(struct address_space * mapping,sector_t block)119 befs_bmap(struct address_space *mapping, sector_t block)
120 {
121 return generic_block_bmap(mapping, block, befs_get_block);
122 }
123
124 /*
125 * Generic function to map a file position (block) to a
126 * disk offset (passed back in bh_result).
127 *
128 * Used by many higher level functions.
129 *
130 * Calls befs_fblock2brun() in datastream.c to do the real work.
131 */
132
133 static int
befs_get_block(struct inode * inode,sector_t block,struct buffer_head * bh_result,int create)134 befs_get_block(struct inode *inode, sector_t block,
135 struct buffer_head *bh_result, int create)
136 {
137 struct super_block *sb = inode->i_sb;
138 befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
139 befs_block_run run = BAD_IADDR;
140 int res;
141 ulong disk_off;
142
143 befs_debug(sb, "---> befs_get_block() for inode %lu, block %ld",
144 (unsigned long)inode->i_ino, (long)block);
145 if (create) {
146 befs_error(sb, "befs_get_block() was asked to write to "
147 "block %ld in inode %lu", (long)block,
148 (unsigned long)inode->i_ino);
149 return -EPERM;
150 }
151
152 res = befs_fblock2brun(sb, ds, block, &run);
153 if (res != BEFS_OK) {
154 befs_error(sb,
155 "<--- %s for inode %lu, block %ld ERROR",
156 __func__, (unsigned long)inode->i_ino,
157 (long)block);
158 return -EFBIG;
159 }
160
161 disk_off = (ulong) iaddr2blockno(sb, &run);
162
163 map_bh(bh_result, inode->i_sb, disk_off);
164
165 befs_debug(sb, "<--- %s for inode %lu, block %ld, disk address %lu",
166 __func__, (unsigned long)inode->i_ino, (long)block,
167 (unsigned long)disk_off);
168
169 return 0;
170 }
171
172 static struct dentry *
befs_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)173 befs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
174 {
175 struct inode *inode;
176 struct super_block *sb = dir->i_sb;
177 const befs_data_stream *ds = &BEFS_I(dir)->i_data.ds;
178 befs_off_t offset;
179 int ret;
180 int utfnamelen;
181 char *utfname;
182 const char *name = dentry->d_name.name;
183
184 befs_debug(sb, "---> %s name %pd inode %ld", __func__,
185 dentry, dir->i_ino);
186
187 /* Convert to UTF-8 */
188 if (BEFS_SB(sb)->nls) {
189 ret =
190 befs_nls2utf(sb, name, strlen(name), &utfname, &utfnamelen);
191 if (ret < 0) {
192 befs_debug(sb, "<--- %s ERROR", __func__);
193 return ERR_PTR(ret);
194 }
195 ret = befs_btree_find(sb, ds, utfname, &offset);
196 kfree(utfname);
197
198 } else {
199 ret = befs_btree_find(sb, ds, name, &offset);
200 }
201
202 if (ret == BEFS_BT_NOT_FOUND) {
203 befs_debug(sb, "<--- %s %pd not found", __func__, dentry);
204 inode = NULL;
205 } else if (ret != BEFS_OK || offset == 0) {
206 befs_error(sb, "<--- %s Error", __func__);
207 inode = ERR_PTR(-ENODATA);
208 } else {
209 inode = befs_iget(dir->i_sb, (ino_t) offset);
210 }
211 befs_debug(sb, "<--- %s", __func__);
212
213 return d_splice_alias(inode, dentry);
214 }
215
216 static int
befs_readdir(struct file * file,struct dir_context * ctx)217 befs_readdir(struct file *file, struct dir_context *ctx)
218 {
219 struct inode *inode = file_inode(file);
220 struct super_block *sb = inode->i_sb;
221 const befs_data_stream *ds = &BEFS_I(inode)->i_data.ds;
222 befs_off_t value;
223 int result;
224 size_t keysize;
225 char keybuf[BEFS_NAME_LEN + 1];
226
227 befs_debug(sb, "---> %s name %pD, inode %ld, ctx->pos %lld",
228 __func__, file, inode->i_ino, ctx->pos);
229
230 while (1) {
231 result = befs_btree_read(sb, ds, ctx->pos, BEFS_NAME_LEN + 1,
232 keybuf, &keysize, &value);
233
234 if (result == BEFS_ERR) {
235 befs_debug(sb, "<--- %s ERROR", __func__);
236 befs_error(sb, "IO error reading %pD (inode %lu)",
237 file, inode->i_ino);
238 return -EIO;
239
240 } else if (result == BEFS_BT_END) {
241 befs_debug(sb, "<--- %s END", __func__);
242 return 0;
243
244 } else if (result == BEFS_BT_EMPTY) {
245 befs_debug(sb, "<--- %s Empty directory", __func__);
246 return 0;
247 }
248
249 /* Convert to NLS */
250 if (BEFS_SB(sb)->nls) {
251 char *nlsname;
252 int nlsnamelen;
253
254 result =
255 befs_utf2nls(sb, keybuf, keysize, &nlsname,
256 &nlsnamelen);
257 if (result < 0) {
258 befs_debug(sb, "<--- %s ERROR", __func__);
259 return result;
260 }
261 if (!dir_emit(ctx, nlsname, nlsnamelen,
262 (ino_t) value, DT_UNKNOWN)) {
263 kfree(nlsname);
264 return 0;
265 }
266 kfree(nlsname);
267 } else {
268 if (!dir_emit(ctx, keybuf, keysize,
269 (ino_t) value, DT_UNKNOWN))
270 return 0;
271 }
272 ctx->pos++;
273 }
274 }
275
276 static struct inode *
befs_alloc_inode(struct super_block * sb)277 befs_alloc_inode(struct super_block *sb)
278 {
279 struct befs_inode_info *bi;
280
281 bi = kmem_cache_alloc(befs_inode_cachep, GFP_KERNEL);
282 if (!bi)
283 return NULL;
284 return &bi->vfs_inode;
285 }
286
befs_free_inode(struct inode * inode)287 static void befs_free_inode(struct inode *inode)
288 {
289 kmem_cache_free(befs_inode_cachep, BEFS_I(inode));
290 }
291
init_once(void * foo)292 static void init_once(void *foo)
293 {
294 struct befs_inode_info *bi = (struct befs_inode_info *) foo;
295
296 inode_init_once(&bi->vfs_inode);
297 }
298
befs_iget(struct super_block * sb,unsigned long ino)299 static struct inode *befs_iget(struct super_block *sb, unsigned long ino)
300 {
301 struct buffer_head *bh;
302 befs_inode *raw_inode;
303 struct befs_sb_info *befs_sb = BEFS_SB(sb);
304 struct befs_inode_info *befs_ino;
305 struct inode *inode;
306
307 befs_debug(sb, "---> %s inode = %lu", __func__, ino);
308
309 inode = iget_locked(sb, ino);
310 if (!inode)
311 return ERR_PTR(-ENOMEM);
312 if (!(inode->i_state & I_NEW))
313 return inode;
314
315 befs_ino = BEFS_I(inode);
316
317 /* convert from vfs's inode number to befs's inode number */
318 befs_ino->i_inode_num = blockno2iaddr(sb, inode->i_ino);
319
320 befs_debug(sb, " real inode number [%u, %hu, %hu]",
321 befs_ino->i_inode_num.allocation_group,
322 befs_ino->i_inode_num.start, befs_ino->i_inode_num.len);
323
324 bh = sb_bread(sb, inode->i_ino);
325 if (!bh) {
326 befs_error(sb, "unable to read inode block - "
327 "inode = %lu", inode->i_ino);
328 goto unacquire_none;
329 }
330
331 raw_inode = (befs_inode *) bh->b_data;
332
333 befs_dump_inode(sb, raw_inode);
334
335 if (befs_check_inode(sb, raw_inode, inode->i_ino) != BEFS_OK) {
336 befs_error(sb, "Bad inode: %lu", inode->i_ino);
337 goto unacquire_bh;
338 }
339
340 inode->i_mode = (umode_t) fs32_to_cpu(sb, raw_inode->mode);
341
342 /*
343 * set uid and gid. But since current BeOS is single user OS, so
344 * you can change by "uid" or "gid" options.
345 */
346
347 inode->i_uid = befs_sb->mount_opts.use_uid ?
348 befs_sb->mount_opts.uid :
349 make_kuid(&init_user_ns, fs32_to_cpu(sb, raw_inode->uid));
350 inode->i_gid = befs_sb->mount_opts.use_gid ?
351 befs_sb->mount_opts.gid :
352 make_kgid(&init_user_ns, fs32_to_cpu(sb, raw_inode->gid));
353
354 set_nlink(inode, 1);
355
356 /*
357 * BEFS's time is 64 bits, but current VFS is 32 bits...
358 * BEFS don't have access time. Nor inode change time. VFS
359 * doesn't have creation time.
360 * Also, the lower 16 bits of the last_modified_time and
361 * create_time are just a counter to help ensure uniqueness
362 * for indexing purposes. (PFD, page 54)
363 */
364
365 inode->i_mtime.tv_sec =
366 fs64_to_cpu(sb, raw_inode->last_modified_time) >> 16;
367 inode->i_mtime.tv_nsec = 0; /* lower 16 bits are not a time */
368 inode->i_ctime = inode->i_mtime;
369 inode->i_atime = inode->i_mtime;
370
371 befs_ino->i_inode_num = fsrun_to_cpu(sb, raw_inode->inode_num);
372 befs_ino->i_parent = fsrun_to_cpu(sb, raw_inode->parent);
373 befs_ino->i_attribute = fsrun_to_cpu(sb, raw_inode->attributes);
374 befs_ino->i_flags = fs32_to_cpu(sb, raw_inode->flags);
375
376 if (S_ISLNK(inode->i_mode) && !(befs_ino->i_flags & BEFS_LONG_SYMLINK)){
377 inode->i_size = 0;
378 inode->i_blocks = befs_sb->block_size / VFS_BLOCK_SIZE;
379 strlcpy(befs_ino->i_data.symlink, raw_inode->data.symlink,
380 BEFS_SYMLINK_LEN);
381 } else {
382 int num_blks;
383
384 befs_ino->i_data.ds =
385 fsds_to_cpu(sb, &raw_inode->data.datastream);
386
387 num_blks = befs_count_blocks(sb, &befs_ino->i_data.ds);
388 inode->i_blocks =
389 num_blks * (befs_sb->block_size / VFS_BLOCK_SIZE);
390 inode->i_size = befs_ino->i_data.ds.size;
391 }
392
393 inode->i_mapping->a_ops = &befs_aops;
394
395 if (S_ISREG(inode->i_mode)) {
396 inode->i_fop = &generic_ro_fops;
397 } else if (S_ISDIR(inode->i_mode)) {
398 inode->i_op = &befs_dir_inode_operations;
399 inode->i_fop = &befs_dir_operations;
400 } else if (S_ISLNK(inode->i_mode)) {
401 if (befs_ino->i_flags & BEFS_LONG_SYMLINK) {
402 inode->i_op = &page_symlink_inode_operations;
403 inode_nohighmem(inode);
404 inode->i_mapping->a_ops = &befs_symlink_aops;
405 } else {
406 inode->i_link = befs_ino->i_data.symlink;
407 inode->i_op = &simple_symlink_inode_operations;
408 }
409 } else {
410 befs_error(sb, "Inode %lu is not a regular file, "
411 "directory or symlink. THAT IS WRONG! BeFS has no "
412 "on disk special files", inode->i_ino);
413 goto unacquire_bh;
414 }
415
416 brelse(bh);
417 befs_debug(sb, "<--- %s", __func__);
418 unlock_new_inode(inode);
419 return inode;
420
421 unacquire_bh:
422 brelse(bh);
423
424 unacquire_none:
425 iget_failed(inode);
426 befs_debug(sb, "<--- %s - Bad inode", __func__);
427 return ERR_PTR(-EIO);
428 }
429
430 /* Initialize the inode cache. Called at fs setup.
431 *
432 * Taken from NFS implementation by Al Viro.
433 */
434 static int __init
befs_init_inodecache(void)435 befs_init_inodecache(void)
436 {
437 befs_inode_cachep = kmem_cache_create_usercopy("befs_inode_cache",
438 sizeof(struct befs_inode_info), 0,
439 (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
440 SLAB_ACCOUNT),
441 offsetof(struct befs_inode_info,
442 i_data.symlink),
443 sizeof_field(struct befs_inode_info,
444 i_data.symlink),
445 init_once);
446 if (befs_inode_cachep == NULL)
447 return -ENOMEM;
448
449 return 0;
450 }
451
452 /* Called at fs teardown.
453 *
454 * Taken from NFS implementation by Al Viro.
455 */
456 static void
befs_destroy_inodecache(void)457 befs_destroy_inodecache(void)
458 {
459 /*
460 * Make sure all delayed rcu free inodes are flushed before we
461 * destroy cache.
462 */
463 rcu_barrier();
464 kmem_cache_destroy(befs_inode_cachep);
465 }
466
467 /*
468 * The inode of symbolic link is different to data stream.
469 * The data stream become link name. Unless the LONG_SYMLINK
470 * flag is set.
471 */
befs_symlink_readpage(struct file * unused,struct page * page)472 static int befs_symlink_readpage(struct file *unused, struct page *page)
473 {
474 struct inode *inode = page->mapping->host;
475 struct super_block *sb = inode->i_sb;
476 struct befs_inode_info *befs_ino = BEFS_I(inode);
477 befs_data_stream *data = &befs_ino->i_data.ds;
478 befs_off_t len = data->size;
479 char *link = page_address(page);
480
481 if (len == 0 || len > PAGE_SIZE) {
482 befs_error(sb, "Long symlink with illegal length");
483 goto fail;
484 }
485 befs_debug(sb, "Follow long symlink");
486
487 if (befs_read_lsymlink(sb, data, link, len) != len) {
488 befs_error(sb, "Failed to read entire long symlink");
489 goto fail;
490 }
491 link[len - 1] = '\0';
492 SetPageUptodate(page);
493 unlock_page(page);
494 return 0;
495 fail:
496 SetPageError(page);
497 unlock_page(page);
498 return -EIO;
499 }
500
501 /*
502 * UTF-8 to NLS charset convert routine
503 *
504 * Uses uni2char() / char2uni() rather than the nls tables directly
505 */
506 static int
befs_utf2nls(struct super_block * sb,const char * in,int in_len,char ** out,int * out_len)507 befs_utf2nls(struct super_block *sb, const char *in,
508 int in_len, char **out, int *out_len)
509 {
510 struct nls_table *nls = BEFS_SB(sb)->nls;
511 int i, o;
512 unicode_t uni;
513 int unilen, utflen;
514 char *result;
515 /* The utf8->nls conversion won't make the final nls string bigger
516 * than the utf one, but if the string is pure ascii they'll have the
517 * same width and an extra char is needed to save the additional \0
518 */
519 int maxlen = in_len + 1;
520
521 befs_debug(sb, "---> %s", __func__);
522
523 if (!nls) {
524 befs_error(sb, "%s called with no NLS table loaded", __func__);
525 return -EINVAL;
526 }
527
528 *out = result = kmalloc(maxlen, GFP_NOFS);
529 if (!*out)
530 return -ENOMEM;
531
532 for (i = o = 0; i < in_len; i += utflen, o += unilen) {
533
534 /* convert from UTF-8 to Unicode */
535 utflen = utf8_to_utf32(&in[i], in_len - i, &uni);
536 if (utflen < 0)
537 goto conv_err;
538
539 /* convert from Unicode to nls */
540 if (uni > MAX_WCHAR_T)
541 goto conv_err;
542 unilen = nls->uni2char(uni, &result[o], in_len - o);
543 if (unilen < 0)
544 goto conv_err;
545 }
546 result[o] = '\0';
547 *out_len = o;
548
549 befs_debug(sb, "<--- %s", __func__);
550
551 return o;
552
553 conv_err:
554 befs_error(sb, "Name using character set %s contains a character that "
555 "cannot be converted to unicode.", nls->charset);
556 befs_debug(sb, "<--- %s", __func__);
557 kfree(result);
558 return -EILSEQ;
559 }
560
561 /**
562 * befs_nls2utf - Convert NLS string to utf8 encodeing
563 * @sb: Superblock
564 * @in: Input string buffer in NLS format
565 * @in_len: Length of input string in bytes
566 * @out: The output string in UTF-8 format
567 * @out_len: Length of the output buffer
568 *
569 * Converts input string @in, which is in the format of the loaded NLS map,
570 * into a utf8 string.
571 *
572 * The destination string @out is allocated by this function and the caller is
573 * responsible for freeing it with kfree()
574 *
575 * On return, *@out_len is the length of @out in bytes.
576 *
577 * On success, the return value is the number of utf8 characters written to
578 * the output buffer @out.
579 *
580 * On Failure, a negative number coresponding to the error code is returned.
581 */
582
583 static int
befs_nls2utf(struct super_block * sb,const char * in,int in_len,char ** out,int * out_len)584 befs_nls2utf(struct super_block *sb, const char *in,
585 int in_len, char **out, int *out_len)
586 {
587 struct nls_table *nls = BEFS_SB(sb)->nls;
588 int i, o;
589 wchar_t uni;
590 int unilen, utflen;
591 char *result;
592 /*
593 * There are nls characters that will translate to 3-chars-wide UTF-8
594 * characters, an additional byte is needed to save the final \0
595 * in special cases
596 */
597 int maxlen = (3 * in_len) + 1;
598
599 befs_debug(sb, "---> %s\n", __func__);
600
601 if (!nls) {
602 befs_error(sb, "%s called with no NLS table loaded.",
603 __func__);
604 return -EINVAL;
605 }
606
607 *out = result = kmalloc(maxlen, GFP_NOFS);
608 if (!*out) {
609 *out_len = 0;
610 return -ENOMEM;
611 }
612
613 for (i = o = 0; i < in_len; i += unilen, o += utflen) {
614
615 /* convert from nls to unicode */
616 unilen = nls->char2uni(&in[i], in_len - i, &uni);
617 if (unilen < 0)
618 goto conv_err;
619
620 /* convert from unicode to UTF-8 */
621 utflen = utf32_to_utf8(uni, &result[o], 3);
622 if (utflen <= 0)
623 goto conv_err;
624 }
625
626 result[o] = '\0';
627 *out_len = o;
628
629 befs_debug(sb, "<--- %s", __func__);
630
631 return i;
632
633 conv_err:
634 befs_error(sb, "Name using character set %s contains a character that "
635 "cannot be converted to unicode.", nls->charset);
636 befs_debug(sb, "<--- %s", __func__);
637 kfree(result);
638 return -EILSEQ;
639 }
640
befs_nfs_get_inode(struct super_block * sb,uint64_t ino,uint32_t generation)641 static struct inode *befs_nfs_get_inode(struct super_block *sb, uint64_t ino,
642 uint32_t generation)
643 {
644 /* No need to handle i_generation */
645 return befs_iget(sb, ino);
646 }
647
648 /*
649 * Map a NFS file handle to a corresponding dentry
650 */
befs_fh_to_dentry(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)651 static struct dentry *befs_fh_to_dentry(struct super_block *sb,
652 struct fid *fid, int fh_len, int fh_type)
653 {
654 return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
655 befs_nfs_get_inode);
656 }
657
658 /*
659 * Find the parent for a file specified by NFS handle
660 */
befs_fh_to_parent(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)661 static struct dentry *befs_fh_to_parent(struct super_block *sb,
662 struct fid *fid, int fh_len, int fh_type)
663 {
664 return generic_fh_to_parent(sb, fid, fh_len, fh_type,
665 befs_nfs_get_inode);
666 }
667
befs_get_parent(struct dentry * child)668 static struct dentry *befs_get_parent(struct dentry *child)
669 {
670 struct inode *parent;
671 struct befs_inode_info *befs_ino = BEFS_I(d_inode(child));
672
673 parent = befs_iget(child->d_sb,
674 (unsigned long)befs_ino->i_parent.start);
675 if (IS_ERR(parent))
676 return ERR_CAST(parent);
677
678 return d_obtain_alias(parent);
679 }
680
681 enum {
682 Opt_uid, Opt_gid, Opt_charset, Opt_debug, Opt_err,
683 };
684
685 static const match_table_t befs_tokens = {
686 {Opt_uid, "uid=%d"},
687 {Opt_gid, "gid=%d"},
688 {Opt_charset, "iocharset=%s"},
689 {Opt_debug, "debug"},
690 {Opt_err, NULL}
691 };
692
693 static int
parse_options(char * options,struct befs_mount_options * opts)694 parse_options(char *options, struct befs_mount_options *opts)
695 {
696 char *p;
697 substring_t args[MAX_OPT_ARGS];
698 int option;
699 kuid_t uid;
700 kgid_t gid;
701
702 /* Initialize options */
703 opts->uid = GLOBAL_ROOT_UID;
704 opts->gid = GLOBAL_ROOT_GID;
705 opts->use_uid = 0;
706 opts->use_gid = 0;
707 opts->iocharset = NULL;
708 opts->debug = 0;
709
710 if (!options)
711 return 1;
712
713 while ((p = strsep(&options, ",")) != NULL) {
714 int token;
715
716 if (!*p)
717 continue;
718
719 token = match_token(p, befs_tokens, args);
720 switch (token) {
721 case Opt_uid:
722 if (match_int(&args[0], &option))
723 return 0;
724 uid = INVALID_UID;
725 if (option >= 0)
726 uid = make_kuid(current_user_ns(), option);
727 if (!uid_valid(uid)) {
728 pr_err("Invalid uid %d, "
729 "using default\n", option);
730 break;
731 }
732 opts->uid = uid;
733 opts->use_uid = 1;
734 break;
735 case Opt_gid:
736 if (match_int(&args[0], &option))
737 return 0;
738 gid = INVALID_GID;
739 if (option >= 0)
740 gid = make_kgid(current_user_ns(), option);
741 if (!gid_valid(gid)) {
742 pr_err("Invalid gid %d, "
743 "using default\n", option);
744 break;
745 }
746 opts->gid = gid;
747 opts->use_gid = 1;
748 break;
749 case Opt_charset:
750 kfree(opts->iocharset);
751 opts->iocharset = match_strdup(&args[0]);
752 if (!opts->iocharset) {
753 pr_err("allocation failure for "
754 "iocharset string\n");
755 return 0;
756 }
757 break;
758 case Opt_debug:
759 opts->debug = 1;
760 break;
761 default:
762 pr_err("Unrecognized mount option \"%s\" "
763 "or missing value\n", p);
764 return 0;
765 }
766 }
767 return 1;
768 }
769
befs_show_options(struct seq_file * m,struct dentry * root)770 static int befs_show_options(struct seq_file *m, struct dentry *root)
771 {
772 struct befs_sb_info *befs_sb = BEFS_SB(root->d_sb);
773 struct befs_mount_options *opts = &befs_sb->mount_opts;
774
775 if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
776 seq_printf(m, ",uid=%u",
777 from_kuid_munged(&init_user_ns, opts->uid));
778 if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
779 seq_printf(m, ",gid=%u",
780 from_kgid_munged(&init_user_ns, opts->gid));
781 if (opts->iocharset)
782 seq_printf(m, ",charset=%s", opts->iocharset);
783 if (opts->debug)
784 seq_puts(m, ",debug");
785 return 0;
786 }
787
788 /* This function has the responsibiltiy of getting the
789 * filesystem ready for unmounting.
790 * Basically, we free everything that we allocated in
791 * befs_read_inode
792 */
793 static void
befs_put_super(struct super_block * sb)794 befs_put_super(struct super_block *sb)
795 {
796 kfree(BEFS_SB(sb)->mount_opts.iocharset);
797 BEFS_SB(sb)->mount_opts.iocharset = NULL;
798 unload_nls(BEFS_SB(sb)->nls);
799 kfree(sb->s_fs_info);
800 sb->s_fs_info = NULL;
801 }
802
803 /* Allocate private field of the superblock, fill it.
804 *
805 * Finish filling the public superblock fields
806 * Make the root directory
807 * Load a set of NLS translations if needed.
808 */
809 static int
befs_fill_super(struct super_block * sb,void * data,int silent)810 befs_fill_super(struct super_block *sb, void *data, int silent)
811 {
812 struct buffer_head *bh;
813 struct befs_sb_info *befs_sb;
814 befs_super_block *disk_sb;
815 struct inode *root;
816 long ret = -EINVAL;
817 const unsigned long sb_block = 0;
818 const off_t x86_sb_off = 512;
819 int blocksize;
820
821 sb->s_fs_info = kzalloc(sizeof(*befs_sb), GFP_KERNEL);
822 if (sb->s_fs_info == NULL)
823 goto unacquire_none;
824
825 befs_sb = BEFS_SB(sb);
826
827 if (!parse_options((char *) data, &befs_sb->mount_opts)) {
828 if (!silent)
829 befs_error(sb, "cannot parse mount options");
830 goto unacquire_priv_sbp;
831 }
832
833 befs_debug(sb, "---> %s", __func__);
834
835 if (!sb_rdonly(sb)) {
836 befs_warning(sb,
837 "No write support. Marking filesystem read-only");
838 sb->s_flags |= SB_RDONLY;
839 }
840
841 /*
842 * Set dummy blocksize to read super block.
843 * Will be set to real fs blocksize later.
844 *
845 * Linux 2.4.10 and later refuse to read blocks smaller than
846 * the logical block size for the device. But we also need to read at
847 * least 1k to get the second 512 bytes of the volume.
848 */
849 blocksize = sb_min_blocksize(sb, 1024);
850 if (!blocksize) {
851 if (!silent)
852 befs_error(sb, "unable to set blocksize");
853 goto unacquire_priv_sbp;
854 }
855
856 bh = sb_bread(sb, sb_block);
857 if (!bh) {
858 if (!silent)
859 befs_error(sb, "unable to read superblock");
860 goto unacquire_priv_sbp;
861 }
862
863 /* account for offset of super block on x86 */
864 disk_sb = (befs_super_block *) bh->b_data;
865 if ((disk_sb->magic1 == BEFS_SUPER_MAGIC1_LE) ||
866 (disk_sb->magic1 == BEFS_SUPER_MAGIC1_BE)) {
867 befs_debug(sb, "Using PPC superblock location");
868 } else {
869 befs_debug(sb, "Using x86 superblock location");
870 disk_sb =
871 (befs_super_block *) ((void *) bh->b_data + x86_sb_off);
872 }
873
874 if ((befs_load_sb(sb, disk_sb) != BEFS_OK) ||
875 (befs_check_sb(sb) != BEFS_OK))
876 goto unacquire_bh;
877
878 befs_dump_super_block(sb, disk_sb);
879
880 brelse(bh);
881
882 if (befs_sb->num_blocks > ~((sector_t)0)) {
883 if (!silent)
884 befs_error(sb, "blocks count: %llu is larger than the host can use",
885 befs_sb->num_blocks);
886 goto unacquire_priv_sbp;
887 }
888
889 /*
890 * set up enough so that it can read an inode
891 * Fill in kernel superblock fields from private sb
892 */
893 sb->s_magic = BEFS_SUPER_MAGIC;
894 /* Set real blocksize of fs */
895 sb_set_blocksize(sb, (ulong) befs_sb->block_size);
896 sb->s_op = &befs_sops;
897 sb->s_export_op = &befs_export_operations;
898 sb->s_time_min = 0;
899 sb->s_time_max = 0xffffffffffffll;
900 root = befs_iget(sb, iaddr2blockno(sb, &(befs_sb->root_dir)));
901 if (IS_ERR(root)) {
902 ret = PTR_ERR(root);
903 goto unacquire_priv_sbp;
904 }
905 sb->s_root = d_make_root(root);
906 if (!sb->s_root) {
907 if (!silent)
908 befs_error(sb, "get root inode failed");
909 goto unacquire_priv_sbp;
910 }
911
912 /* load nls library */
913 if (befs_sb->mount_opts.iocharset) {
914 befs_debug(sb, "Loading nls: %s",
915 befs_sb->mount_opts.iocharset);
916 befs_sb->nls = load_nls(befs_sb->mount_opts.iocharset);
917 if (!befs_sb->nls) {
918 befs_warning(sb, "Cannot load nls %s"
919 " loading default nls",
920 befs_sb->mount_opts.iocharset);
921 befs_sb->nls = load_nls_default();
922 }
923 /* load default nls if none is specified in mount options */
924 } else {
925 befs_debug(sb, "Loading default nls");
926 befs_sb->nls = load_nls_default();
927 }
928
929 return 0;
930
931 unacquire_bh:
932 brelse(bh);
933
934 unacquire_priv_sbp:
935 kfree(befs_sb->mount_opts.iocharset);
936 kfree(sb->s_fs_info);
937 sb->s_fs_info = NULL;
938
939 unacquire_none:
940 return ret;
941 }
942
943 static int
befs_remount(struct super_block * sb,int * flags,char * data)944 befs_remount(struct super_block *sb, int *flags, char *data)
945 {
946 sync_filesystem(sb);
947 if (!(*flags & SB_RDONLY))
948 return -EINVAL;
949 return 0;
950 }
951
952 static int
befs_statfs(struct dentry * dentry,struct kstatfs * buf)953 befs_statfs(struct dentry *dentry, struct kstatfs *buf)
954 {
955 struct super_block *sb = dentry->d_sb;
956 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
957
958 befs_debug(sb, "---> %s", __func__);
959
960 buf->f_type = BEFS_SUPER_MAGIC;
961 buf->f_bsize = sb->s_blocksize;
962 buf->f_blocks = BEFS_SB(sb)->num_blocks;
963 buf->f_bfree = BEFS_SB(sb)->num_blocks - BEFS_SB(sb)->used_blocks;
964 buf->f_bavail = buf->f_bfree;
965 buf->f_files = 0; /* UNKNOWN */
966 buf->f_ffree = 0; /* UNKNOWN */
967 buf->f_fsid = u64_to_fsid(id);
968 buf->f_namelen = BEFS_NAME_LEN;
969
970 befs_debug(sb, "<--- %s", __func__);
971
972 return 0;
973 }
974
975 static struct dentry *
befs_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * data)976 befs_mount(struct file_system_type *fs_type, int flags, const char *dev_name,
977 void *data)
978 {
979 return mount_bdev(fs_type, flags, dev_name, data, befs_fill_super);
980 }
981
982 static struct file_system_type befs_fs_type = {
983 .owner = THIS_MODULE,
984 .name = "befs",
985 .mount = befs_mount,
986 .kill_sb = kill_block_super,
987 .fs_flags = FS_REQUIRES_DEV,
988 };
989 MODULE_ALIAS_FS("befs");
990
991 static int __init
init_befs_fs(void)992 init_befs_fs(void)
993 {
994 int err;
995
996 pr_info("version: %s\n", BEFS_VERSION);
997
998 err = befs_init_inodecache();
999 if (err)
1000 goto unacquire_none;
1001
1002 err = register_filesystem(&befs_fs_type);
1003 if (err)
1004 goto unacquire_inodecache;
1005
1006 return 0;
1007
1008 unacquire_inodecache:
1009 befs_destroy_inodecache();
1010
1011 unacquire_none:
1012 return err;
1013 }
1014
1015 static void __exit
exit_befs_fs(void)1016 exit_befs_fs(void)
1017 {
1018 befs_destroy_inodecache();
1019
1020 unregister_filesystem(&befs_fs_type);
1021 }
1022
1023 /*
1024 * Macros that typecheck the init and exit functions,
1025 * ensures that they are called at init and cleanup,
1026 * and eliminates warnings about unused functions.
1027 */
1028 module_init(init_befs_fs)
1029 module_exit(exit_befs_fs)
1030