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TOMOYO Linux Cross Reference
Linux/fs/befs/linuxvfs.c

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  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 
 26 #include "befs.h"
 27 #include "btree.h"
 28 #include "inode.h"
 29 #include "datastream.h"
 30 #include "super.h"
 31 #include "io.h"
 32 
 33 MODULE_DESCRIPTION("BeOS File System (BeFS) driver");
 34 MODULE_AUTHOR("Will Dyson");
 35 MODULE_LICENSE("GPL");
 36 
 37 /* The units the vfs expects inode->i_blocks to be in */
 38 #define VFS_BLOCK_SIZE 512
 39 
 40 static int befs_readdir(struct file *, struct dir_context *);
 41 static int befs_get_block(struct inode *, sector_t, struct buffer_head *, int);
 42 static int befs_readpage(struct file *file, struct page *page);
 43 static sector_t befs_bmap(struct address_space *mapping, sector_t block);
 44 static struct dentry *befs_lookup(struct inode *, struct dentry *,
 45                                   unsigned int);
 46 static struct inode *befs_iget(struct super_block *, unsigned long);
 47 static struct inode *befs_alloc_inode(struct super_block *sb);
 48 static void befs_free_inode(struct inode *inode);
 49 static void befs_destroy_inodecache(void);
 50 static int befs_symlink_readpage(struct file *, struct page *);
 51 static int befs_utf2nls(struct super_block *sb, const char *in, int in_len,
 52                         char **out, int *out_len);
 53 static int befs_nls2utf(struct super_block *sb, const char *in, int in_len,
 54                         char **out, int *out_len);
 55 static void befs_put_super(struct super_block *);
 56 static int befs_remount(struct super_block *, int *, char *);
 57 static int befs_statfs(struct dentry *, struct kstatfs *);
 58 static int befs_show_options(struct seq_file *, struct dentry *);
 59 static int parse_options(char *, struct befs_mount_options *);
 60 static struct dentry *befs_fh_to_dentry(struct super_block *sb,
 61                                 struct fid *fid, int fh_len, int fh_type);
 62 static struct dentry *befs_fh_to_parent(struct super_block *sb,
 63                                 struct fid *fid, int fh_len, int fh_type);
 64 static struct dentry *befs_get_parent(struct dentry *child);
 65 
 66 static const struct super_operations befs_sops = {
 67         .alloc_inode    = befs_alloc_inode,     /* allocate a new inode */
 68         .free_inode     = befs_free_inode, /* deallocate an inode */
 69         .put_super      = befs_put_super,       /* uninit super */
 70         .statfs         = befs_statfs,  /* statfs */
 71         .remount_fs     = befs_remount,
 72         .show_options   = befs_show_options,
 73 };
 74 
 75 /* slab cache for befs_inode_info objects */
 76 static struct kmem_cache *befs_inode_cachep;
 77 
 78 static const struct file_operations befs_dir_operations = {
 79         .read           = generic_read_dir,
 80         .iterate_shared = befs_readdir,
 81         .llseek         = generic_file_llseek,
 82 };
 83 
 84 static const struct inode_operations befs_dir_inode_operations = {
 85         .lookup         = befs_lookup,
 86 };
 87 
 88 static const struct address_space_operations befs_aops = {
 89         .readpage       = befs_readpage,
 90         .bmap           = befs_bmap,
 91 };
 92 
 93 static const struct address_space_operations befs_symlink_aops = {
 94         .readpage       = befs_symlink_readpage,
 95 };
 96 
 97 static const struct export_operations befs_export_operations = {
 98         .fh_to_dentry   = befs_fh_to_dentry,
 99         .fh_to_parent   = befs_fh_to_parent,
100         .get_parent     = befs_get_parent,
101 };
102 
103 /*
104  * Called by generic_file_read() to read a page of data
105  *
106  * In turn, simply calls a generic block read function and
107  * passes it the address of befs_get_block, for mapping file
108  * positions to disk blocks.
109  */
110 static int
111 befs_readpage(struct file *file, struct page *page)
112 {
113         return block_read_full_page(page, befs_get_block);
114 }
115 
116 static sector_t
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
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 *
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
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 *
275 befs_alloc_inode(struct super_block *sb)
276 {
277         struct befs_inode_info *bi;
278 
279         bi = kmem_cache_alloc(befs_inode_cachep, GFP_KERNEL);
280         if (!bi)
281                 return NULL;
282         return &bi->vfs_inode;
283 }
284 
285 static void befs_free_inode(struct inode *inode)
286 {
287         kmem_cache_free(befs_inode_cachep, BEFS_I(inode));
288 }
289 
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 
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->i_ctime = 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                 strlcpy(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
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
455 befs_destroy_inodecache(void)
456 {
457         /*
458          * Make sure all delayed rcu free inodes are flushed before we
459          * destroy cache.
460          */
461         rcu_barrier();
462         kmem_cache_destroy(befs_inode_cachep);
463 }
464 
465 /*
466  * The inode of symbolic link is different to data stream.
467  * The data stream become link name. Unless the LONG_SYMLINK
468  * flag is set.
469  */
470 static int befs_symlink_readpage(struct file *unused, struct page *page)
471 {
472         struct inode *inode = page->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 = page_address(page);
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         SetPageUptodate(page);
491         unlock_page(page);
492         return 0;
493 fail:
494         SetPageError(page);
495         unlock_page(page);
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
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
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 
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  */
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  */
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 
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
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 
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
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
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         root = befs_iget(sb, iaddr2blockno(sb, &(befs_sb->root_dir)));
897         if (IS_ERR(root)) {
898                 ret = PTR_ERR(root);
899                 goto unacquire_priv_sbp;
900         }
901         sb->s_root = d_make_root(root);
902         if (!sb->s_root) {
903                 if (!silent)
904                         befs_error(sb, "get root inode failed");
905                 goto unacquire_priv_sbp;
906         }
907 
908         /* load nls library */
909         if (befs_sb->mount_opts.iocharset) {
910                 befs_debug(sb, "Loading nls: %s",
911                            befs_sb->mount_opts.iocharset);
912                 befs_sb->nls = load_nls(befs_sb->mount_opts.iocharset);
913                 if (!befs_sb->nls) {
914                         befs_warning(sb, "Cannot load nls %s"
915                                         " loading default nls",
916                                         befs_sb->mount_opts.iocharset);
917                         befs_sb->nls = load_nls_default();
918                 }
919         /* load default nls if none is specified  in mount options */
920         } else {
921                 befs_debug(sb, "Loading default nls");
922                 befs_sb->nls = load_nls_default();
923         }
924 
925         return 0;
926 
927 unacquire_bh:
928         brelse(bh);
929 
930 unacquire_priv_sbp:
931         kfree(befs_sb->mount_opts.iocharset);
932         kfree(sb->s_fs_info);
933         sb->s_fs_info = NULL;
934 
935 unacquire_none:
936         return ret;
937 }
938 
939 static int
940 befs_remount(struct super_block *sb, int *flags, char *data)
941 {
942         sync_filesystem(sb);
943         if (!(*flags & SB_RDONLY))
944                 return -EINVAL;
945         return 0;
946 }
947 
948 static int
949 befs_statfs(struct dentry *dentry, struct kstatfs *buf)
950 {
951         struct super_block *sb = dentry->d_sb;
952         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
953 
954         befs_debug(sb, "---> %s", __func__);
955 
956         buf->f_type = BEFS_SUPER_MAGIC;
957         buf->f_bsize = sb->s_blocksize;
958         buf->f_blocks = BEFS_SB(sb)->num_blocks;
959         buf->f_bfree = BEFS_SB(sb)->num_blocks - BEFS_SB(sb)->used_blocks;
960         buf->f_bavail = buf->f_bfree;
961         buf->f_files = 0;       /* UNKNOWN */
962         buf->f_ffree = 0;       /* UNKNOWN */
963         buf->f_fsid.val[0] = (u32)id;
964         buf->f_fsid.val[1] = (u32)(id >> 32);
965         buf->f_namelen = BEFS_NAME_LEN;
966 
967         befs_debug(sb, "<--- %s", __func__);
968 
969         return 0;
970 }
971 
972 static struct dentry *
973 befs_mount(struct file_system_type *fs_type, int flags, const char *dev_name,
974             void *data)
975 {
976         return mount_bdev(fs_type, flags, dev_name, data, befs_fill_super);
977 }
978 
979 static struct file_system_type befs_fs_type = {
980         .owner          = THIS_MODULE,
981         .name           = "befs",
982         .mount          = befs_mount,
983         .kill_sb        = kill_block_super,
984         .fs_flags       = FS_REQUIRES_DEV,
985 };
986 MODULE_ALIAS_FS("befs");
987 
988 static int __init
989 init_befs_fs(void)
990 {
991         int err;
992 
993         pr_info("version: %s\n", BEFS_VERSION);
994 
995         err = befs_init_inodecache();
996         if (err)
997                 goto unacquire_none;
998 
999         err = register_filesystem(&befs_fs_type);
1000         if (err)
1001                 goto unacquire_inodecache;
1002 
1003         return 0;
1004 
1005 unacquire_inodecache:
1006         befs_destroy_inodecache();
1007 
1008 unacquire_none:
1009         return err;
1010 }
1011 
1012 static void __exit
1013 exit_befs_fs(void)
1014 {
1015         befs_destroy_inodecache();
1016 
1017         unregister_filesystem(&befs_fs_type);
1018 }
1019 
1020 /*
1021  * Macros that typecheck the init and exit functions,
1022  * ensures that they are called at init and cleanup,
1023  * and eliminates warnings about unused functions.
1024  */
1025 module_init(init_befs_fs)
1026 module_exit(exit_befs_fs)
1027 

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