~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/fs/fat/inode.c

Version: ~ [ linux-5.4-rc7 ] ~ [ linux-5.3.11 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.84 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.154 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.201 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.201 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.77 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  *  linux/fs/fat/inode.c
  3  *
  4  *  Written 1992,1993 by Werner Almesberger
  5  *  VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner
  6  *  Rewritten for the constant inumbers support by Al Viro
  7  *
  8  *  Fixes:
  9  *
 10  *      Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
 11  */
 12 
 13 #include <linux/module.h>
 14 #include <linux/init.h>
 15 #include <linux/time.h>
 16 #include <linux/slab.h>
 17 #include <linux/smp_lock.h>
 18 #include <linux/seq_file.h>
 19 #include <linux/pagemap.h>
 20 #include <linux/mpage.h>
 21 #include <linux/buffer_head.h>
 22 #include <linux/exportfs.h>
 23 #include <linux/mount.h>
 24 #include <linux/vfs.h>
 25 #include <linux/parser.h>
 26 #include <linux/uio.h>
 27 #include <linux/writeback.h>
 28 #include <linux/log2.h>
 29 #include <linux/hash.h>
 30 #include <asm/unaligned.h>
 31 #include "fat.h"
 32 
 33 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
 34 /* if user don't select VFAT, this is undefined. */
 35 #define CONFIG_FAT_DEFAULT_IOCHARSET    ""
 36 #endif
 37 
 38 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
 39 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
 40 
 41 
 42 static int fat_add_cluster(struct inode *inode)
 43 {
 44         int err, cluster;
 45 
 46         err = fat_alloc_clusters(inode, &cluster, 1);
 47         if (err)
 48                 return err;
 49         /* FIXME: this cluster should be added after data of this
 50          * cluster is writed */
 51         err = fat_chain_add(inode, cluster, 1);
 52         if (err)
 53                 fat_free_clusters(inode, cluster);
 54         return err;
 55 }
 56 
 57 static inline int __fat_get_block(struct inode *inode, sector_t iblock,
 58                                   unsigned long *max_blocks,
 59                                   struct buffer_head *bh_result, int create)
 60 {
 61         struct super_block *sb = inode->i_sb;
 62         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 63         unsigned long mapped_blocks;
 64         sector_t phys;
 65         int err, offset;
 66 
 67         err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
 68         if (err)
 69                 return err;
 70         if (phys) {
 71                 map_bh(bh_result, sb, phys);
 72                 *max_blocks = min(mapped_blocks, *max_blocks);
 73                 return 0;
 74         }
 75         if (!create)
 76                 return 0;
 77 
 78         if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
 79                 fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)",
 80                         MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
 81                 return -EIO;
 82         }
 83 
 84         offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
 85         if (!offset) {
 86                 /* TODO: multiple cluster allocation would be desirable. */
 87                 err = fat_add_cluster(inode);
 88                 if (err)
 89                         return err;
 90         }
 91         /* available blocks on this cluster */
 92         mapped_blocks = sbi->sec_per_clus - offset;
 93 
 94         *max_blocks = min(mapped_blocks, *max_blocks);
 95         MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
 96 
 97         err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
 98         if (err)
 99                 return err;
100 
101         BUG_ON(!phys);
102         BUG_ON(*max_blocks != mapped_blocks);
103         set_buffer_new(bh_result);
104         map_bh(bh_result, sb, phys);
105 
106         return 0;
107 }
108 
109 static int fat_get_block(struct inode *inode, sector_t iblock,
110                          struct buffer_head *bh_result, int create)
111 {
112         struct super_block *sb = inode->i_sb;
113         unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
114         int err;
115 
116         err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
117         if (err)
118                 return err;
119         bh_result->b_size = max_blocks << sb->s_blocksize_bits;
120         return 0;
121 }
122 
123 static int fat_writepage(struct page *page, struct writeback_control *wbc)
124 {
125         return block_write_full_page(page, fat_get_block, wbc);
126 }
127 
128 static int fat_writepages(struct address_space *mapping,
129                           struct writeback_control *wbc)
130 {
131         return mpage_writepages(mapping, wbc, fat_get_block);
132 }
133 
134 static int fat_readpage(struct file *file, struct page *page)
135 {
136         return mpage_readpage(page, fat_get_block);
137 }
138 
139 static int fat_readpages(struct file *file, struct address_space *mapping,
140                          struct list_head *pages, unsigned nr_pages)
141 {
142         return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
143 }
144 
145 static int fat_write_begin(struct file *file, struct address_space *mapping,
146                         loff_t pos, unsigned len, unsigned flags,
147                         struct page **pagep, void **fsdata)
148 {
149         *pagep = NULL;
150         return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
151                                 fat_get_block,
152                                 &MSDOS_I(mapping->host)->mmu_private);
153 }
154 
155 static int fat_write_end(struct file *file, struct address_space *mapping,
156                         loff_t pos, unsigned len, unsigned copied,
157                         struct page *pagep, void *fsdata)
158 {
159         struct inode *inode = mapping->host;
160         int err;
161         err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
162         if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
163                 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
164                 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
165                 mark_inode_dirty(inode);
166         }
167         return err;
168 }
169 
170 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
171                              const struct iovec *iov,
172                              loff_t offset, unsigned long nr_segs)
173 {
174         struct file *file = iocb->ki_filp;
175         struct inode *inode = file->f_mapping->host;
176 
177         if (rw == WRITE) {
178                 /*
179                  * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
180                  * so we need to update the ->mmu_private to block boundary.
181                  *
182                  * But we must fill the remaining area or hole by nul for
183                  * updating ->mmu_private.
184                  *
185                  * Return 0, and fallback to normal buffered write.
186                  */
187                 loff_t size = offset + iov_length(iov, nr_segs);
188                 if (MSDOS_I(inode)->mmu_private < size)
189                         return 0;
190         }
191 
192         /*
193          * FAT need to use the DIO_LOCKING for avoiding the race
194          * condition of fat_get_block() and ->truncate().
195          */
196         return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
197                                   offset, nr_segs, fat_get_block, NULL);
198 }
199 
200 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
201 {
202         sector_t blocknr;
203 
204         /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
205         down_read(&mapping->host->i_alloc_sem);
206         blocknr = generic_block_bmap(mapping, block, fat_get_block);
207         up_read(&mapping->host->i_alloc_sem);
208 
209         return blocknr;
210 }
211 
212 static const struct address_space_operations fat_aops = {
213         .readpage       = fat_readpage,
214         .readpages      = fat_readpages,
215         .writepage      = fat_writepage,
216         .writepages     = fat_writepages,
217         .sync_page      = block_sync_page,
218         .write_begin    = fat_write_begin,
219         .write_end      = fat_write_end,
220         .direct_IO      = fat_direct_IO,
221         .bmap           = _fat_bmap
222 };
223 
224 /*
225  * New FAT inode stuff. We do the following:
226  *      a) i_ino is constant and has nothing with on-disk location.
227  *      b) FAT manages its own cache of directory entries.
228  *      c) *This* cache is indexed by on-disk location.
229  *      d) inode has an associated directory entry, all right, but
230  *              it may be unhashed.
231  *      e) currently entries are stored within struct inode. That should
232  *              change.
233  *      f) we deal with races in the following way:
234  *              1. readdir() and lookup() do FAT-dir-cache lookup.
235  *              2. rename() unhashes the F-d-c entry and rehashes it in
236  *                      a new place.
237  *              3. unlink() and rmdir() unhash F-d-c entry.
238  *              4. fat_write_inode() checks whether the thing is unhashed.
239  *                      If it is we silently return. If it isn't we do bread(),
240  *                      check if the location is still valid and retry if it
241  *                      isn't. Otherwise we do changes.
242  *              5. Spinlock is used to protect hash/unhash/location check/lookup
243  *              6. fat_clear_inode() unhashes the F-d-c entry.
244  *              7. lookup() and readdir() do igrab() if they find a F-d-c entry
245  *                      and consider negative result as cache miss.
246  */
247 
248 static void fat_hash_init(struct super_block *sb)
249 {
250         struct msdos_sb_info *sbi = MSDOS_SB(sb);
251         int i;
252 
253         spin_lock_init(&sbi->inode_hash_lock);
254         for (i = 0; i < FAT_HASH_SIZE; i++)
255                 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
256 }
257 
258 static inline unsigned long fat_hash(loff_t i_pos)
259 {
260         return hash_32(i_pos, FAT_HASH_BITS);
261 }
262 
263 void fat_attach(struct inode *inode, loff_t i_pos)
264 {
265         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
266         struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
267 
268         spin_lock(&sbi->inode_hash_lock);
269         MSDOS_I(inode)->i_pos = i_pos;
270         hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
271         spin_unlock(&sbi->inode_hash_lock);
272 }
273 EXPORT_SYMBOL_GPL(fat_attach);
274 
275 void fat_detach(struct inode *inode)
276 {
277         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
278         spin_lock(&sbi->inode_hash_lock);
279         MSDOS_I(inode)->i_pos = 0;
280         hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
281         spin_unlock(&sbi->inode_hash_lock);
282 }
283 EXPORT_SYMBOL_GPL(fat_detach);
284 
285 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
286 {
287         struct msdos_sb_info *sbi = MSDOS_SB(sb);
288         struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
289         struct hlist_node *_p;
290         struct msdos_inode_info *i;
291         struct inode *inode = NULL;
292 
293         spin_lock(&sbi->inode_hash_lock);
294         hlist_for_each_entry(i, _p, head, i_fat_hash) {
295                 BUG_ON(i->vfs_inode.i_sb != sb);
296                 if (i->i_pos != i_pos)
297                         continue;
298                 inode = igrab(&i->vfs_inode);
299                 if (inode)
300                         break;
301         }
302         spin_unlock(&sbi->inode_hash_lock);
303         return inode;
304 }
305 
306 static int is_exec(unsigned char *extension)
307 {
308         unsigned char *exe_extensions = "EXECOMBAT", *walk;
309 
310         for (walk = exe_extensions; *walk; walk += 3)
311                 if (!strncmp(extension, walk, 3))
312                         return 1;
313         return 0;
314 }
315 
316 static int fat_calc_dir_size(struct inode *inode)
317 {
318         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
319         int ret, fclus, dclus;
320 
321         inode->i_size = 0;
322         if (MSDOS_I(inode)->i_start == 0)
323                 return 0;
324 
325         ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
326         if (ret < 0)
327                 return ret;
328         inode->i_size = (fclus + 1) << sbi->cluster_bits;
329 
330         return 0;
331 }
332 
333 /* doesn't deal with root inode */
334 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
335 {
336         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
337         int error;
338 
339         MSDOS_I(inode)->i_pos = 0;
340         inode->i_uid = sbi->options.fs_uid;
341         inode->i_gid = sbi->options.fs_gid;
342         inode->i_version++;
343         inode->i_generation = get_seconds();
344 
345         if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
346                 inode->i_generation &= ~1;
347                 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
348                 inode->i_op = sbi->dir_ops;
349                 inode->i_fop = &fat_dir_operations;
350 
351                 MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
352                 if (sbi->fat_bits == 32)
353                         MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
354 
355                 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
356                 error = fat_calc_dir_size(inode);
357                 if (error < 0)
358                         return error;
359                 MSDOS_I(inode)->mmu_private = inode->i_size;
360 
361                 inode->i_nlink = fat_subdirs(inode);
362         } else { /* not a directory */
363                 inode->i_generation |= 1;
364                 inode->i_mode = fat_make_mode(sbi, de->attr,
365                         ((sbi->options.showexec && !is_exec(de->name + 8))
366                          ? S_IRUGO|S_IWUGO : S_IRWXUGO));
367                 MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
368                 if (sbi->fat_bits == 32)
369                         MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
370 
371                 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
372                 inode->i_size = le32_to_cpu(de->size);
373                 inode->i_op = &fat_file_inode_operations;
374                 inode->i_fop = &fat_file_operations;
375                 inode->i_mapping->a_ops = &fat_aops;
376                 MSDOS_I(inode)->mmu_private = inode->i_size;
377         }
378         if (de->attr & ATTR_SYS) {
379                 if (sbi->options.sys_immutable)
380                         inode->i_flags |= S_IMMUTABLE;
381         }
382         fat_save_attrs(inode, de->attr);
383 
384         inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
385                            & ~((loff_t)sbi->cluster_size - 1)) >> 9;
386 
387         fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
388         if (sbi->options.isvfat) {
389                 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
390                                   de->cdate, de->ctime_cs);
391                 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
392         } else
393                 inode->i_ctime = inode->i_atime = inode->i_mtime;
394 
395         return 0;
396 }
397 
398 struct inode *fat_build_inode(struct super_block *sb,
399                         struct msdos_dir_entry *de, loff_t i_pos)
400 {
401         struct inode *inode;
402         int err;
403 
404         inode = fat_iget(sb, i_pos);
405         if (inode)
406                 goto out;
407         inode = new_inode(sb);
408         if (!inode) {
409                 inode = ERR_PTR(-ENOMEM);
410                 goto out;
411         }
412         inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
413         inode->i_version = 1;
414         err = fat_fill_inode(inode, de);
415         if (err) {
416                 iput(inode);
417                 inode = ERR_PTR(err);
418                 goto out;
419         }
420         fat_attach(inode, i_pos);
421         insert_inode_hash(inode);
422 out:
423         return inode;
424 }
425 
426 EXPORT_SYMBOL_GPL(fat_build_inode);
427 
428 static void fat_delete_inode(struct inode *inode)
429 {
430         truncate_inode_pages(&inode->i_data, 0);
431         inode->i_size = 0;
432         fat_truncate(inode);
433         clear_inode(inode);
434 }
435 
436 static void fat_clear_inode(struct inode *inode)
437 {
438         fat_cache_inval_inode(inode);
439         fat_detach(inode);
440 }
441 
442 static void fat_write_super(struct super_block *sb)
443 {
444         lock_super(sb);
445         sb->s_dirt = 0;
446 
447         if (!(sb->s_flags & MS_RDONLY))
448                 fat_clusters_flush(sb);
449         unlock_super(sb);
450 }
451 
452 static int fat_sync_fs(struct super_block *sb, int wait)
453 {
454         int err = 0;
455 
456         if (sb->s_dirt) {
457                 lock_super(sb);
458                 sb->s_dirt = 0;
459                 err = fat_clusters_flush(sb);
460                 unlock_super(sb);
461         }
462 
463         return err;
464 }
465 
466 static void fat_put_super(struct super_block *sb)
467 {
468         struct msdos_sb_info *sbi = MSDOS_SB(sb);
469 
470         lock_kernel();
471 
472         if (sb->s_dirt)
473                 fat_write_super(sb);
474 
475         iput(sbi->fat_inode);
476 
477         unload_nls(sbi->nls_disk);
478         unload_nls(sbi->nls_io);
479 
480         if (sbi->options.iocharset != fat_default_iocharset)
481                 kfree(sbi->options.iocharset);
482 
483         sb->s_fs_info = NULL;
484         kfree(sbi);
485 
486         unlock_kernel();
487 }
488 
489 static struct kmem_cache *fat_inode_cachep;
490 
491 static struct inode *fat_alloc_inode(struct super_block *sb)
492 {
493         struct msdos_inode_info *ei;
494         ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
495         if (!ei)
496                 return NULL;
497         return &ei->vfs_inode;
498 }
499 
500 static void fat_destroy_inode(struct inode *inode)
501 {
502         kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
503 }
504 
505 static void init_once(void *foo)
506 {
507         struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
508 
509         spin_lock_init(&ei->cache_lru_lock);
510         ei->nr_caches = 0;
511         ei->cache_valid_id = FAT_CACHE_VALID + 1;
512         INIT_LIST_HEAD(&ei->cache_lru);
513         INIT_HLIST_NODE(&ei->i_fat_hash);
514         inode_init_once(&ei->vfs_inode);
515 }
516 
517 static int __init fat_init_inodecache(void)
518 {
519         fat_inode_cachep = kmem_cache_create("fat_inode_cache",
520                                              sizeof(struct msdos_inode_info),
521                                              0, (SLAB_RECLAIM_ACCOUNT|
522                                                 SLAB_MEM_SPREAD),
523                                              init_once);
524         if (fat_inode_cachep == NULL)
525                 return -ENOMEM;
526         return 0;
527 }
528 
529 static void __exit fat_destroy_inodecache(void)
530 {
531         kmem_cache_destroy(fat_inode_cachep);
532 }
533 
534 static int fat_remount(struct super_block *sb, int *flags, char *data)
535 {
536         struct msdos_sb_info *sbi = MSDOS_SB(sb);
537         *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
538         return 0;
539 }
540 
541 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
542 {
543         struct super_block *sb = dentry->d_sb;
544         struct msdos_sb_info *sbi = MSDOS_SB(sb);
545         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
546 
547         /* If the count of free cluster is still unknown, counts it here. */
548         if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
549                 int err = fat_count_free_clusters(dentry->d_sb);
550                 if (err)
551                         return err;
552         }
553 
554         buf->f_type = dentry->d_sb->s_magic;
555         buf->f_bsize = sbi->cluster_size;
556         buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
557         buf->f_bfree = sbi->free_clusters;
558         buf->f_bavail = sbi->free_clusters;
559         buf->f_fsid.val[0] = (u32)id;
560         buf->f_fsid.val[1] = (u32)(id >> 32);
561         buf->f_namelen = sbi->options.isvfat ? FAT_LFN_LEN : 12;
562 
563         return 0;
564 }
565 
566 static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,
567                                     struct inode *inode)
568 {
569         loff_t i_pos;
570 #if BITS_PER_LONG == 32
571         spin_lock(&sbi->inode_hash_lock);
572 #endif
573         i_pos = MSDOS_I(inode)->i_pos;
574 #if BITS_PER_LONG == 32
575         spin_unlock(&sbi->inode_hash_lock);
576 #endif
577         return i_pos;
578 }
579 
580 static int fat_write_inode(struct inode *inode, int wait)
581 {
582         struct super_block *sb = inode->i_sb;
583         struct msdos_sb_info *sbi = MSDOS_SB(sb);
584         struct buffer_head *bh;
585         struct msdos_dir_entry *raw_entry;
586         loff_t i_pos;
587         int err;
588 
589         if (inode->i_ino == MSDOS_ROOT_INO)
590                 return 0;
591 
592 retry:
593         i_pos = fat_i_pos_read(sbi, inode);
594         if (!i_pos)
595                 return 0;
596 
597         bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits);
598         if (!bh) {
599                 printk(KERN_ERR "FAT: unable to read inode block "
600                        "for updating (i_pos %lld)\n", i_pos);
601                 return -EIO;
602         }
603         spin_lock(&sbi->inode_hash_lock);
604         if (i_pos != MSDOS_I(inode)->i_pos) {
605                 spin_unlock(&sbi->inode_hash_lock);
606                 brelse(bh);
607                 goto retry;
608         }
609 
610         raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
611             [i_pos & (sbi->dir_per_block - 1)];
612         if (S_ISDIR(inode->i_mode))
613                 raw_entry->size = 0;
614         else
615                 raw_entry->size = cpu_to_le32(inode->i_size);
616         raw_entry->attr = fat_make_attrs(inode);
617         raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart);
618         raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16);
619         fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
620                           &raw_entry->date, NULL);
621         if (sbi->options.isvfat) {
622                 __le16 atime;
623                 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
624                                   &raw_entry->cdate, &raw_entry->ctime_cs);
625                 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
626                                   &raw_entry->adate, NULL);
627         }
628         spin_unlock(&sbi->inode_hash_lock);
629         mark_buffer_dirty(bh);
630         err = 0;
631         if (wait)
632                 err = sync_dirty_buffer(bh);
633         brelse(bh);
634         return err;
635 }
636 
637 int fat_sync_inode(struct inode *inode)
638 {
639         return fat_write_inode(inode, 1);
640 }
641 
642 EXPORT_SYMBOL_GPL(fat_sync_inode);
643 
644 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt);
645 static const struct super_operations fat_sops = {
646         .alloc_inode    = fat_alloc_inode,
647         .destroy_inode  = fat_destroy_inode,
648         .write_inode    = fat_write_inode,
649         .delete_inode   = fat_delete_inode,
650         .put_super      = fat_put_super,
651         .write_super    = fat_write_super,
652         .sync_fs        = fat_sync_fs,
653         .statfs         = fat_statfs,
654         .clear_inode    = fat_clear_inode,
655         .remount_fs     = fat_remount,
656 
657         .show_options   = fat_show_options,
658 };
659 
660 /*
661  * a FAT file handle with fhtype 3 is
662  *  0/  i_ino - for fast, reliable lookup if still in the cache
663  *  1/  i_generation - to see if i_ino is still valid
664  *          bit 0 == 0 iff directory
665  *  2/  i_pos(8-39) - if ino has changed, but still in cache
666  *  3/  i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos
667  *  4/  i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc
668  *
669  * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum
670  * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits
671  * of i_logstart is used to store the directory entry offset.
672  */
673 
674 static struct dentry *fat_fh_to_dentry(struct super_block *sb,
675                 struct fid *fid, int fh_len, int fh_type)
676 {
677         struct inode *inode = NULL;
678         struct dentry *result;
679         u32 *fh = fid->raw;
680 
681         if (fh_len < 5 || fh_type != 3)
682                 return NULL;
683 
684         inode = ilookup(sb, fh[0]);
685         if (!inode || inode->i_generation != fh[1]) {
686                 if (inode)
687                         iput(inode);
688                 inode = NULL;
689         }
690         if (!inode) {
691                 loff_t i_pos;
692                 int i_logstart = fh[3] & 0x0fffffff;
693 
694                 i_pos = (loff_t)fh[2] << 8;
695                 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28);
696 
697                 /* try 2 - see if i_pos is in F-d-c
698                  * require i_logstart to be the same
699                  * Will fail if you truncate and then re-write
700                  */
701 
702                 inode = fat_iget(sb, i_pos);
703                 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) {
704                         iput(inode);
705                         inode = NULL;
706                 }
707         }
708 
709         /*
710          * For now, do nothing if the inode is not found.
711          *
712          * What we could do is:
713          *
714          *      - follow the file starting at fh[4], and record the ".." entry,
715          *        and the name of the fh[2] entry.
716          *      - then follow the ".." file finding the next step up.
717          *
718          * This way we build a path to the root of the tree. If this works, we
719          * lookup the path and so get this inode into the cache.  Finally try
720          * the fat_iget lookup again.  If that fails, then we are totally out
721          * of luck.  But all that is for another day
722          */
723         result = d_obtain_alias(inode);
724         if (!IS_ERR(result))
725                 result->d_op = sb->s_root->d_op;
726         return result;
727 }
728 
729 static int
730 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable)
731 {
732         int len = *lenp;
733         struct inode *inode =  de->d_inode;
734         u32 ipos_h, ipos_m, ipos_l;
735 
736         if (len < 5)
737                 return 255; /* no room */
738 
739         ipos_h = MSDOS_I(inode)->i_pos >> 8;
740         ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24;
741         ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28;
742         *lenp = 5;
743         fh[0] = inode->i_ino;
744         fh[1] = inode->i_generation;
745         fh[2] = ipos_h;
746         fh[3] = ipos_m | MSDOS_I(inode)->i_logstart;
747         spin_lock(&de->d_lock);
748         fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart;
749         spin_unlock(&de->d_lock);
750         return 3;
751 }
752 
753 static struct dentry *fat_get_parent(struct dentry *child)
754 {
755         struct super_block *sb = child->d_sb;
756         struct buffer_head *bh;
757         struct msdos_dir_entry *de;
758         loff_t i_pos;
759         struct dentry *parent;
760         struct inode *inode;
761         int err;
762 
763         lock_super(sb);
764 
765         err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos);
766         if (err) {
767                 parent = ERR_PTR(err);
768                 goto out;
769         }
770         inode = fat_build_inode(sb, de, i_pos);
771         brelse(bh);
772 
773         parent = d_obtain_alias(inode);
774         if (!IS_ERR(parent))
775                 parent->d_op = sb->s_root->d_op;
776 out:
777         unlock_super(sb);
778 
779         return parent;
780 }
781 
782 static const struct export_operations fat_export_ops = {
783         .encode_fh      = fat_encode_fh,
784         .fh_to_dentry   = fat_fh_to_dentry,
785         .get_parent     = fat_get_parent,
786 };
787 
788 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt)
789 {
790         struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb);
791         struct fat_mount_options *opts = &sbi->options;
792         int isvfat = opts->isvfat;
793 
794         if (opts->fs_uid != 0)
795                 seq_printf(m, ",uid=%u", opts->fs_uid);
796         if (opts->fs_gid != 0)
797                 seq_printf(m, ",gid=%u", opts->fs_gid);
798         seq_printf(m, ",fmask=%04o", opts->fs_fmask);
799         seq_printf(m, ",dmask=%04o", opts->fs_dmask);
800         if (opts->allow_utime)
801                 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
802         if (sbi->nls_disk)
803                 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset);
804         if (isvfat) {
805                 if (sbi->nls_io)
806                         seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
807 
808                 switch (opts->shortname) {
809                 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
810                         seq_puts(m, ",shortname=win95");
811                         break;
812                 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
813                         seq_puts(m, ",shortname=winnt");
814                         break;
815                 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
816                         seq_puts(m, ",shortname=mixed");
817                         break;
818                 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
819                         seq_puts(m, ",shortname=lower");
820                         break;
821                 default:
822                         seq_puts(m, ",shortname=unknown");
823                         break;
824                 }
825         }
826         if (opts->name_check != 'n')
827                 seq_printf(m, ",check=%c", opts->name_check);
828         if (opts->usefree)
829                 seq_puts(m, ",usefree");
830         if (opts->quiet)
831                 seq_puts(m, ",quiet");
832         if (opts->showexec)
833                 seq_puts(m, ",showexec");
834         if (opts->sys_immutable)
835                 seq_puts(m, ",sys_immutable");
836         if (!isvfat) {
837                 if (opts->dotsOK)
838                         seq_puts(m, ",dotsOK=yes");
839                 if (opts->nocase)
840                         seq_puts(m, ",nocase");
841         } else {
842                 if (opts->utf8)
843                         seq_puts(m, ",utf8");
844                 if (opts->unicode_xlate)
845                         seq_puts(m, ",uni_xlate");
846                 if (!opts->numtail)
847                         seq_puts(m, ",nonumtail");
848                 if (opts->rodir)
849                         seq_puts(m, ",rodir");
850         }
851         if (opts->flush)
852                 seq_puts(m, ",flush");
853         if (opts->tz_utc)
854                 seq_puts(m, ",tz=UTC");
855         if (opts->errors == FAT_ERRORS_CONT)
856                 seq_puts(m, ",errors=continue");
857         else if (opts->errors == FAT_ERRORS_PANIC)
858                 seq_puts(m, ",errors=panic");
859         else
860                 seq_puts(m, ",errors=remount-ro");
861 
862         return 0;
863 }
864 
865 enum {
866         Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
867         Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
868         Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
869         Opt_immutable, Opt_dots, Opt_nodots,
870         Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
871         Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
872         Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
873         Opt_obsolate, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
874         Opt_err_panic, Opt_err_ro, Opt_err,
875 };
876 
877 static const match_table_t fat_tokens = {
878         {Opt_check_r, "check=relaxed"},
879         {Opt_check_s, "check=strict"},
880         {Opt_check_n, "check=normal"},
881         {Opt_check_r, "check=r"},
882         {Opt_check_s, "check=s"},
883         {Opt_check_n, "check=n"},
884         {Opt_uid, "uid=%u"},
885         {Opt_gid, "gid=%u"},
886         {Opt_umask, "umask=%o"},
887         {Opt_dmask, "dmask=%o"},
888         {Opt_fmask, "fmask=%o"},
889         {Opt_allow_utime, "allow_utime=%o"},
890         {Opt_codepage, "codepage=%u"},
891         {Opt_usefree, "usefree"},
892         {Opt_nocase, "nocase"},
893         {Opt_quiet, "quiet"},
894         {Opt_showexec, "showexec"},
895         {Opt_debug, "debug"},
896         {Opt_immutable, "sys_immutable"},
897         {Opt_flush, "flush"},
898         {Opt_tz_utc, "tz=UTC"},
899         {Opt_err_cont, "errors=continue"},
900         {Opt_err_panic, "errors=panic"},
901         {Opt_err_ro, "errors=remount-ro"},
902         {Opt_obsolate, "conv=binary"},
903         {Opt_obsolate, "conv=text"},
904         {Opt_obsolate, "conv=auto"},
905         {Opt_obsolate, "conv=b"},
906         {Opt_obsolate, "conv=t"},
907         {Opt_obsolate, "conv=a"},
908         {Opt_obsolate, "fat=%u"},
909         {Opt_obsolate, "blocksize=%u"},
910         {Opt_obsolate, "cvf_format=%20s"},
911         {Opt_obsolate, "cvf_options=%100s"},
912         {Opt_obsolate, "posix"},
913         {Opt_err, NULL},
914 };
915 static const match_table_t msdos_tokens = {
916         {Opt_nodots, "nodots"},
917         {Opt_nodots, "dotsOK=no"},
918         {Opt_dots, "dots"},
919         {Opt_dots, "dotsOK=yes"},
920         {Opt_err, NULL}
921 };
922 static const match_table_t vfat_tokens = {
923         {Opt_charset, "iocharset=%s"},
924         {Opt_shortname_lower, "shortname=lower"},
925         {Opt_shortname_win95, "shortname=win95"},
926         {Opt_shortname_winnt, "shortname=winnt"},
927         {Opt_shortname_mixed, "shortname=mixed"},
928         {Opt_utf8_no, "utf8=0"},                /* 0 or no or false */
929         {Opt_utf8_no, "utf8=no"},
930         {Opt_utf8_no, "utf8=false"},
931         {Opt_utf8_yes, "utf8=1"},               /* empty or 1 or yes or true */
932         {Opt_utf8_yes, "utf8=yes"},
933         {Opt_utf8_yes, "utf8=true"},
934         {Opt_utf8_yes, "utf8"},
935         {Opt_uni_xl_no, "uni_xlate=0"},         /* 0 or no or false */
936         {Opt_uni_xl_no, "uni_xlate=no"},
937         {Opt_uni_xl_no, "uni_xlate=false"},
938         {Opt_uni_xl_yes, "uni_xlate=1"},        /* empty or 1 or yes or true */
939         {Opt_uni_xl_yes, "uni_xlate=yes"},
940         {Opt_uni_xl_yes, "uni_xlate=true"},
941         {Opt_uni_xl_yes, "uni_xlate"},
942         {Opt_nonumtail_no, "nonumtail=0"},      /* 0 or no or false */
943         {Opt_nonumtail_no, "nonumtail=no"},
944         {Opt_nonumtail_no, "nonumtail=false"},
945         {Opt_nonumtail_yes, "nonumtail=1"},     /* empty or 1 or yes or true */
946         {Opt_nonumtail_yes, "nonumtail=yes"},
947         {Opt_nonumtail_yes, "nonumtail=true"},
948         {Opt_nonumtail_yes, "nonumtail"},
949         {Opt_rodir, "rodir"},
950         {Opt_err, NULL}
951 };
952 
953 static int parse_options(char *options, int is_vfat, int silent, int *debug,
954                          struct fat_mount_options *opts)
955 {
956         char *p;
957         substring_t args[MAX_OPT_ARGS];
958         int option;
959         char *iocharset;
960 
961         opts->isvfat = is_vfat;
962 
963         opts->fs_uid = current_uid();
964         opts->fs_gid = current_gid();
965         opts->fs_fmask = opts->fs_dmask = current_umask();
966         opts->allow_utime = -1;
967         opts->codepage = fat_default_codepage;
968         opts->iocharset = fat_default_iocharset;
969         if (is_vfat) {
970                 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
971                 opts->rodir = 0;
972         } else {
973                 opts->shortname = 0;
974                 opts->rodir = 1;
975         }
976         opts->name_check = 'n';
977         opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK =  0;
978         opts->utf8 = opts->unicode_xlate = 0;
979         opts->numtail = 1;
980         opts->usefree = opts->nocase = 0;
981         opts->tz_utc = 0;
982         opts->errors = FAT_ERRORS_RO;
983         *debug = 0;
984 
985         if (!options)
986                 goto out;
987 
988         while ((p = strsep(&options, ",")) != NULL) {
989                 int token;
990                 if (!*p)
991                         continue;
992 
993                 token = match_token(p, fat_tokens, args);
994                 if (token == Opt_err) {
995                         if (is_vfat)
996                                 token = match_token(p, vfat_tokens, args);
997                         else
998                                 token = match_token(p, msdos_tokens, args);
999                 }
1000                 switch (token) {
1001                 case Opt_check_s:
1002                         opts->name_check = 's';
1003                         break;
1004                 case Opt_check_r:
1005                         opts->name_check = 'r';
1006                         break;
1007                 case Opt_check_n:
1008                         opts->name_check = 'n';
1009                         break;
1010                 case Opt_usefree:
1011                         opts->usefree = 1;
1012                         break;
1013                 case Opt_nocase:
1014                         if (!is_vfat)
1015                                 opts->nocase = 1;
1016                         else {
1017                                 /* for backward compatibility */
1018                                 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1019                                         | VFAT_SFN_CREATE_WIN95;
1020                         }
1021                         break;
1022                 case Opt_quiet:
1023                         opts->quiet = 1;
1024                         break;
1025                 case Opt_showexec:
1026                         opts->showexec = 1;
1027                         break;
1028                 case Opt_debug:
1029                         *debug = 1;
1030                         break;
1031                 case Opt_immutable:
1032                         opts->sys_immutable = 1;
1033                         break;
1034                 case Opt_uid:
1035                         if (match_int(&args[0], &option))
1036                                 return 0;
1037                         opts->fs_uid = option;
1038                         break;
1039                 case Opt_gid:
1040                         if (match_int(&args[0], &option))
1041                                 return 0;
1042                         opts->fs_gid = option;
1043                         break;
1044                 case Opt_umask:
1045                         if (match_octal(&args[0], &option))
1046                                 return 0;
1047                         opts->fs_fmask = opts->fs_dmask = option;
1048                         break;
1049                 case Opt_dmask:
1050                         if (match_octal(&args[0], &option))
1051                                 return 0;
1052                         opts->fs_dmask = option;
1053                         break;
1054                 case Opt_fmask:
1055                         if (match_octal(&args[0], &option))
1056                                 return 0;
1057                         opts->fs_fmask = option;
1058                         break;
1059                 case Opt_allow_utime:
1060                         if (match_octal(&args[0], &option))
1061                                 return 0;
1062                         opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1063                         break;
1064                 case Opt_codepage:
1065                         if (match_int(&args[0], &option))
1066                                 return 0;
1067                         opts->codepage = option;
1068                         break;
1069                 case Opt_flush:
1070                         opts->flush = 1;
1071                         break;
1072                 case Opt_tz_utc:
1073                         opts->tz_utc = 1;
1074                         break;
1075                 case Opt_err_cont:
1076                         opts->errors = FAT_ERRORS_CONT;
1077                         break;
1078                 case Opt_err_panic:
1079                         opts->errors = FAT_ERRORS_PANIC;
1080                         break;
1081                 case Opt_err_ro:
1082                         opts->errors = FAT_ERRORS_RO;
1083                         break;
1084 
1085                 /* msdos specific */
1086                 case Opt_dots:
1087                         opts->dotsOK = 1;
1088                         break;
1089                 case Opt_nodots:
1090                         opts->dotsOK = 0;
1091                         break;
1092 
1093                 /* vfat specific */
1094                 case Opt_charset:
1095                         if (opts->iocharset != fat_default_iocharset)
1096                                 kfree(opts->iocharset);
1097                         iocharset = match_strdup(&args[0]);
1098                         if (!iocharset)
1099                                 return -ENOMEM;
1100                         opts->iocharset = iocharset;
1101                         break;
1102                 case Opt_shortname_lower:
1103                         opts->shortname = VFAT_SFN_DISPLAY_LOWER
1104                                         | VFAT_SFN_CREATE_WIN95;
1105                         break;
1106                 case Opt_shortname_win95:
1107                         opts->shortname = VFAT_SFN_DISPLAY_WIN95
1108                                         | VFAT_SFN_CREATE_WIN95;
1109                         break;
1110                 case Opt_shortname_winnt:
1111                         opts->shortname = VFAT_SFN_DISPLAY_WINNT
1112                                         | VFAT_SFN_CREATE_WINNT;
1113                         break;
1114                 case Opt_shortname_mixed:
1115                         opts->shortname = VFAT_SFN_DISPLAY_WINNT
1116                                         | VFAT_SFN_CREATE_WIN95;
1117                         break;
1118                 case Opt_utf8_no:               /* 0 or no or false */
1119                         opts->utf8 = 0;
1120                         break;
1121                 case Opt_utf8_yes:              /* empty or 1 or yes or true */
1122                         opts->utf8 = 1;
1123                         break;
1124                 case Opt_uni_xl_no:             /* 0 or no or false */
1125                         opts->unicode_xlate = 0;
1126                         break;
1127                 case Opt_uni_xl_yes:            /* empty or 1 or yes or true */
1128                         opts->unicode_xlate = 1;
1129                         break;
1130                 case Opt_nonumtail_no:          /* 0 or no or false */
1131                         opts->numtail = 1;      /* negated option */
1132                         break;
1133                 case Opt_nonumtail_yes:         /* empty or 1 or yes or true */
1134                         opts->numtail = 0;      /* negated option */
1135                         break;
1136                 case Opt_rodir:
1137                         opts->rodir = 1;
1138                         break;
1139 
1140                 /* obsolete mount options */
1141                 case Opt_obsolate:
1142                         printk(KERN_INFO "FAT: \"%s\" option is obsolete, "
1143                                "not supported now\n", p);
1144                         break;
1145                 /* unknown option */
1146                 default:
1147                         if (!silent) {
1148                                 printk(KERN_ERR
1149                                        "FAT: Unrecognized mount option \"%s\" "
1150                                        "or missing value\n", p);
1151                         }
1152                         return -EINVAL;
1153                 }
1154         }
1155 
1156 out:
1157         /* UTF-8 doesn't provide FAT semantics */
1158         if (!strcmp(opts->iocharset, "utf8")) {
1159                 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset"
1160                        " for FAT filesystems, filesystem will be "
1161                        "case sensitive!\n");
1162         }
1163 
1164         /* If user doesn't specify allow_utime, it's initialized from dmask. */
1165         if (opts->allow_utime == (unsigned short)-1)
1166                 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1167         if (opts->unicode_xlate)
1168                 opts->utf8 = 0;
1169 
1170         return 0;
1171 }
1172 
1173 static int fat_read_root(struct inode *inode)
1174 {
1175         struct super_block *sb = inode->i_sb;
1176         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1177         int error;
1178 
1179         MSDOS_I(inode)->i_pos = 0;
1180         inode->i_uid = sbi->options.fs_uid;
1181         inode->i_gid = sbi->options.fs_gid;
1182         inode->i_version++;
1183         inode->i_generation = 0;
1184         inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1185         inode->i_op = sbi->dir_ops;
1186         inode->i_fop = &fat_dir_operations;
1187         if (sbi->fat_bits == 32) {
1188                 MSDOS_I(inode)->i_start = sbi->root_cluster;
1189                 error = fat_calc_dir_size(inode);
1190                 if (error < 0)
1191                         return error;
1192         } else {
1193                 MSDOS_I(inode)->i_start = 0;
1194                 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1195         }
1196         inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1197                            & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1198         MSDOS_I(inode)->i_logstart = 0;
1199         MSDOS_I(inode)->mmu_private = inode->i_size;
1200 
1201         fat_save_attrs(inode, ATTR_DIR);
1202         inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1203         inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1204         inode->i_nlink = fat_subdirs(inode)+2;
1205 
1206         return 0;
1207 }
1208 
1209 /*
1210  * Read the super block of an MS-DOS FS.
1211  */
1212 int fat_fill_super(struct super_block *sb, void *data, int silent,
1213                    const struct inode_operations *fs_dir_inode_ops, int isvfat)
1214 {
1215         struct inode *root_inode = NULL, *fat_inode = NULL;
1216         struct buffer_head *bh;
1217         struct fat_boot_sector *b;
1218         struct msdos_sb_info *sbi;
1219         u16 logical_sector_size;
1220         u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1221         int debug;
1222         unsigned int media;
1223         long error;
1224         char buf[50];
1225 
1226         /*
1227          * GFP_KERNEL is ok here, because while we do hold the
1228          * supeblock lock, memory pressure can't call back into
1229          * the filesystem, since we're only just about to mount
1230          * it and have no inodes etc active!
1231          */
1232         sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1233         if (!sbi)
1234                 return -ENOMEM;
1235         sb->s_fs_info = sbi;
1236 
1237         sb->s_flags |= MS_NODIRATIME;
1238         sb->s_magic = MSDOS_SUPER_MAGIC;
1239         sb->s_op = &fat_sops;
1240         sb->s_export_op = &fat_export_ops;
1241         sbi->dir_ops = fs_dir_inode_ops;
1242 
1243         error = parse_options(data, isvfat, silent, &debug, &sbi->options);
1244         if (error)
1245                 goto out_fail;
1246 
1247         error = -EIO;
1248         sb_min_blocksize(sb, 512);
1249         bh = sb_bread(sb, 0);
1250         if (bh == NULL) {
1251                 printk(KERN_ERR "FAT: unable to read boot sector\n");
1252                 goto out_fail;
1253         }
1254 
1255         b = (struct fat_boot_sector *) bh->b_data;
1256         if (!b->reserved) {
1257                 if (!silent)
1258                         printk(KERN_ERR "FAT: bogus number of reserved sectors\n");
1259                 brelse(bh);
1260                 goto out_invalid;
1261         }
1262         if (!b->fats) {
1263                 if (!silent)
1264                         printk(KERN_ERR "FAT: bogus number of FAT structure\n");
1265                 brelse(bh);
1266                 goto out_invalid;
1267         }
1268 
1269         /*
1270          * Earlier we checked here that b->secs_track and b->head are nonzero,
1271          * but it turns out valid FAT filesystems can have zero there.
1272          */
1273 
1274         media = b->media;
1275         if (!fat_valid_media(media)) {
1276                 if (!silent)
1277                         printk(KERN_ERR "FAT: invalid media value (0x%02x)\n",
1278                                media);
1279                 brelse(bh);
1280                 goto out_invalid;
1281         }
1282         logical_sector_size = get_unaligned_le16(&b->sector_size);
1283         if (!is_power_of_2(logical_sector_size)
1284             || (logical_sector_size < 512)
1285             || (logical_sector_size > 4096)) {
1286                 if (!silent)
1287                         printk(KERN_ERR "FAT: bogus logical sector size %u\n",
1288                                logical_sector_size);
1289                 brelse(bh);
1290                 goto out_invalid;
1291         }
1292         sbi->sec_per_clus = b->sec_per_clus;
1293         if (!is_power_of_2(sbi->sec_per_clus)) {
1294                 if (!silent)
1295                         printk(KERN_ERR "FAT: bogus sectors per cluster %u\n",
1296                                sbi->sec_per_clus);
1297                 brelse(bh);
1298                 goto out_invalid;
1299         }
1300 
1301         if (logical_sector_size < sb->s_blocksize) {
1302                 printk(KERN_ERR "FAT: logical sector size too small for device"
1303                        " (logical sector size = %u)\n", logical_sector_size);
1304                 brelse(bh);
1305                 goto out_fail;
1306         }
1307         if (logical_sector_size > sb->s_blocksize) {
1308                 brelse(bh);
1309 
1310                 if (!sb_set_blocksize(sb, logical_sector_size)) {
1311                         printk(KERN_ERR "FAT: unable to set blocksize %u\n",
1312                                logical_sector_size);
1313                         goto out_fail;
1314                 }
1315                 bh = sb_bread(sb, 0);
1316                 if (bh == NULL) {
1317                         printk(KERN_ERR "FAT: unable to read boot sector"
1318                                " (logical sector size = %lu)\n",
1319                                sb->s_blocksize);
1320                         goto out_fail;
1321                 }
1322                 b = (struct fat_boot_sector *) bh->b_data;
1323         }
1324 
1325         sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1326         sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1327         sbi->fats = b->fats;
1328         sbi->fat_bits = 0;              /* Don't know yet */
1329         sbi->fat_start = le16_to_cpu(b->reserved);
1330         sbi->fat_length = le16_to_cpu(b->fat_length);
1331         sbi->root_cluster = 0;
1332         sbi->free_clusters = -1;        /* Don't know yet */
1333         sbi->free_clus_valid = 0;
1334         sbi->prev_free = FAT_START_ENT;
1335 
1336         if (!sbi->fat_length && b->fat32_length) {
1337                 struct fat_boot_fsinfo *fsinfo;
1338                 struct buffer_head *fsinfo_bh;
1339 
1340                 /* Must be FAT32 */
1341                 sbi->fat_bits = 32;
1342                 sbi->fat_length = le32_to_cpu(b->fat32_length);
1343                 sbi->root_cluster = le32_to_cpu(b->root_cluster);
1344 
1345                 sb->s_maxbytes = 0xffffffff;
1346 
1347                 /* MC - if info_sector is 0, don't multiply by 0 */
1348                 sbi->fsinfo_sector = le16_to_cpu(b->info_sector);
1349                 if (sbi->fsinfo_sector == 0)
1350                         sbi->fsinfo_sector = 1;
1351 
1352                 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1353                 if (fsinfo_bh == NULL) {
1354                         printk(KERN_ERR "FAT: bread failed, FSINFO block"
1355                                " (sector = %lu)\n", sbi->fsinfo_sector);
1356                         brelse(bh);
1357                         goto out_fail;
1358                 }
1359 
1360                 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1361                 if (!IS_FSINFO(fsinfo)) {
1362                         printk(KERN_WARNING "FAT: Invalid FSINFO signature: "
1363                                "0x%08x, 0x%08x (sector = %lu)\n",
1364                                le32_to_cpu(fsinfo->signature1),
1365                                le32_to_cpu(fsinfo->signature2),
1366                                sbi->fsinfo_sector);
1367                 } else {
1368                         if (sbi->options.usefree)
1369                                 sbi->free_clus_valid = 1;
1370                         sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1371                         sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1372                 }
1373 
1374                 brelse(fsinfo_bh);
1375         }
1376 
1377         sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1378         sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1379 
1380         sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1381         sbi->dir_entries = get_unaligned_le16(&b->dir_entries);
1382         if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1383                 if (!silent)
1384                         printk(KERN_ERR "FAT: bogus directroy-entries per block"
1385                                " (%u)\n", sbi->dir_entries);
1386                 brelse(bh);
1387                 goto out_invalid;
1388         }
1389 
1390         rootdir_sectors = sbi->dir_entries
1391                 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1392         sbi->data_start = sbi->dir_start + rootdir_sectors;
1393         total_sectors = get_unaligned_le16(&b->sectors);
1394         if (total_sectors == 0)
1395                 total_sectors = le32_to_cpu(b->total_sect);
1396 
1397         total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1398 
1399         if (sbi->fat_bits != 32)
1400                 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1401 
1402         /* check that FAT table does not overflow */
1403         fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1404         total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1405         if (total_clusters > MAX_FAT(sb)) {
1406                 if (!silent)
1407                         printk(KERN_ERR "FAT: count of clusters too big (%u)\n",
1408                                total_clusters);
1409                 brelse(bh);
1410                 goto out_invalid;
1411         }
1412 
1413         sbi->max_cluster = total_clusters + FAT_START_ENT;
1414         /* check the free_clusters, it's not necessarily correct */
1415         if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1416                 sbi->free_clusters = -1;
1417         /* check the prev_free, it's not necessarily correct */
1418         sbi->prev_free %= sbi->max_cluster;
1419         if (sbi->prev_free < FAT_START_ENT)
1420                 sbi->prev_free = FAT_START_ENT;
1421 
1422         brelse(bh);
1423 
1424         /* set up enough so that it can read an inode */
1425         fat_hash_init(sb);
1426         fat_ent_access_init(sb);
1427 
1428         /*
1429          * The low byte of FAT's first entry must have same value with
1430          * media-field.  But in real world, too many devices is
1431          * writing wrong value.  So, removed that validity check.
1432          *
1433          * if (FAT_FIRST_ENT(sb, media) != first)
1434          */
1435 
1436         error = -EINVAL;
1437         sprintf(buf, "cp%d", sbi->options.codepage);
1438         sbi->nls_disk = load_nls(buf);
1439         if (!sbi->nls_disk) {
1440                 printk(KERN_ERR "FAT: codepage %s not found\n", buf);
1441                 goto out_fail;
1442         }
1443 
1444         /* FIXME: utf8 is using iocharset for upper/lower conversion */
1445         if (sbi->options.isvfat) {
1446                 sbi->nls_io = load_nls(sbi->options.iocharset);
1447                 if (!sbi->nls_io) {
1448                         printk(KERN_ERR "FAT: IO charset %s not found\n",
1449                                sbi->options.iocharset);
1450                         goto out_fail;
1451                 }
1452         }
1453 
1454         error = -ENOMEM;
1455         fat_inode = new_inode(sb);
1456         if (!fat_inode)
1457                 goto out_fail;
1458         MSDOS_I(fat_inode)->i_pos = 0;
1459         sbi->fat_inode = fat_inode;
1460         root_inode = new_inode(sb);
1461         if (!root_inode)
1462                 goto out_fail;
1463         root_inode->i_ino = MSDOS_ROOT_INO;
1464         root_inode->i_version = 1;
1465         error = fat_read_root(root_inode);
1466         if (error < 0)
1467                 goto out_fail;
1468         error = -ENOMEM;
1469         insert_inode_hash(root_inode);
1470         sb->s_root = d_alloc_root(root_inode);
1471         if (!sb->s_root) {
1472                 printk(KERN_ERR "FAT: get root inode failed\n");
1473                 goto out_fail;
1474         }
1475 
1476         return 0;
1477 
1478 out_invalid:
1479         error = -EINVAL;
1480         if (!silent)
1481                 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem"
1482                        " on dev %s.\n", sb->s_id);
1483 
1484 out_fail:
1485         if (fat_inode)
1486                 iput(fat_inode);
1487         if (root_inode)
1488                 iput(root_inode);
1489         if (sbi->nls_io)
1490                 unload_nls(sbi->nls_io);
1491         if (sbi->nls_disk)
1492                 unload_nls(sbi->nls_disk);
1493         if (sbi->options.iocharset != fat_default_iocharset)
1494                 kfree(sbi->options.iocharset);
1495         sb->s_fs_info = NULL;
1496         kfree(sbi);
1497         return error;
1498 }
1499 
1500 EXPORT_SYMBOL_GPL(fat_fill_super);
1501 
1502 /*
1503  * helper function for fat_flush_inodes.  This writes both the inode
1504  * and the file data blocks, waiting for in flight data blocks before
1505  * the start of the call.  It does not wait for any io started
1506  * during the call
1507  */
1508 static int writeback_inode(struct inode *inode)
1509 {
1510 
1511         int ret;
1512         struct address_space *mapping = inode->i_mapping;
1513         struct writeback_control wbc = {
1514                .sync_mode = WB_SYNC_NONE,
1515               .nr_to_write = 0,
1516         };
1517         /* if we used WB_SYNC_ALL, sync_inode waits for the io for the
1518         * inode to finish.  So WB_SYNC_NONE is sent down to sync_inode
1519         * and filemap_fdatawrite is used for the data blocks
1520         */
1521         ret = sync_inode(inode, &wbc);
1522         if (!ret)
1523                ret = filemap_fdatawrite(mapping);
1524         return ret;
1525 }
1526 
1527 /*
1528  * write data and metadata corresponding to i1 and i2.  The io is
1529  * started but we do not wait for any of it to finish.
1530  *
1531  * filemap_flush is used for the block device, so if there is a dirty
1532  * page for a block already in flight, we will not wait and start the
1533  * io over again
1534  */
1535 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1536 {
1537         int ret = 0;
1538         if (!MSDOS_SB(sb)->options.flush)
1539                 return 0;
1540         if (i1)
1541                 ret = writeback_inode(i1);
1542         if (!ret && i2)
1543                 ret = writeback_inode(i2);
1544         if (!ret) {
1545                 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1546                 ret = filemap_flush(mapping);
1547         }
1548         return ret;
1549 }
1550 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1551 
1552 static int __init init_fat_fs(void)
1553 {
1554         int err;
1555 
1556         err = fat_cache_init();
1557         if (err)
1558                 return err;
1559 
1560         err = fat_init_inodecache();
1561         if (err)
1562                 goto failed;
1563 
1564         return 0;
1565 
1566 failed:
1567         fat_cache_destroy();
1568         return err;
1569 }
1570 
1571 static void __exit exit_fat_fs(void)
1572 {
1573         fat_cache_destroy();
1574         fat_destroy_inodecache();
1575 }
1576 
1577 module_init(init_fat_fs)
1578 module_exit(exit_fat_fs)
1579 
1580 MODULE_LICENSE("GPL");
1581 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp