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

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