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

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

Version: ~ [ linux-5.4-rc3 ] ~ [ linux-5.3.6 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.79 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.149 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.196 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.196 ] ~ [ 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-3.16.75 ] ~ [ 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 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  *  linux/fs/fat/file.c
  4  *
  5  *  Written 1992,1993 by Werner Almesberger
  6  *
  7  *  regular file handling primitives for fat-based filesystems
  8  */
  9 
 10 #include <linux/capability.h>
 11 #include <linux/module.h>
 12 #include <linux/compat.h>
 13 #include <linux/mount.h>
 14 #include <linux/blkdev.h>
 15 #include <linux/backing-dev.h>
 16 #include <linux/fsnotify.h>
 17 #include <linux/security.h>
 18 #include <linux/falloc.h>
 19 #include "fat.h"
 20 
 21 static long fat_fallocate(struct file *file, int mode,
 22                           loff_t offset, loff_t len);
 23 
 24 static int fat_ioctl_get_attributes(struct inode *inode, u32 __user *user_attr)
 25 {
 26         u32 attr;
 27 
 28         inode_lock(inode);
 29         attr = fat_make_attrs(inode);
 30         inode_unlock(inode);
 31 
 32         return put_user(attr, user_attr);
 33 }
 34 
 35 static int fat_ioctl_set_attributes(struct file *file, u32 __user *user_attr)
 36 {
 37         struct inode *inode = file_inode(file);
 38         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 39         int is_dir = S_ISDIR(inode->i_mode);
 40         u32 attr, oldattr;
 41         struct iattr ia;
 42         int err;
 43 
 44         err = get_user(attr, user_attr);
 45         if (err)
 46                 goto out;
 47 
 48         err = mnt_want_write_file(file);
 49         if (err)
 50                 goto out;
 51         inode_lock(inode);
 52 
 53         /*
 54          * ATTR_VOLUME and ATTR_DIR cannot be changed; this also
 55          * prevents the user from turning us into a VFAT
 56          * longname entry.  Also, we obviously can't set
 57          * any of the NTFS attributes in the high 24 bits.
 58          */
 59         attr &= 0xff & ~(ATTR_VOLUME | ATTR_DIR);
 60         /* Merge in ATTR_VOLUME and ATTR_DIR */
 61         attr |= (MSDOS_I(inode)->i_attrs & ATTR_VOLUME) |
 62                 (is_dir ? ATTR_DIR : 0);
 63         oldattr = fat_make_attrs(inode);
 64 
 65         /* Equivalent to a chmod() */
 66         ia.ia_valid = ATTR_MODE | ATTR_CTIME;
 67         ia.ia_ctime = current_time(inode);
 68         if (is_dir)
 69                 ia.ia_mode = fat_make_mode(sbi, attr, S_IRWXUGO);
 70         else {
 71                 ia.ia_mode = fat_make_mode(sbi, attr,
 72                         S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO));
 73         }
 74 
 75         /* The root directory has no attributes */
 76         if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) {
 77                 err = -EINVAL;
 78                 goto out_unlock_inode;
 79         }
 80 
 81         if (sbi->options.sys_immutable &&
 82             ((attr | oldattr) & ATTR_SYS) &&
 83             !capable(CAP_LINUX_IMMUTABLE)) {
 84                 err = -EPERM;
 85                 goto out_unlock_inode;
 86         }
 87 
 88         /*
 89          * The security check is questionable...  We single
 90          * out the RO attribute for checking by the security
 91          * module, just because it maps to a file mode.
 92          */
 93         err = security_inode_setattr(file->f_path.dentry, &ia);
 94         if (err)
 95                 goto out_unlock_inode;
 96 
 97         /* This MUST be done before doing anything irreversible... */
 98         err = fat_setattr(file->f_path.dentry, &ia);
 99         if (err)
100                 goto out_unlock_inode;
101 
102         fsnotify_change(file->f_path.dentry, ia.ia_valid);
103         if (sbi->options.sys_immutable) {
104                 if (attr & ATTR_SYS)
105                         inode->i_flags |= S_IMMUTABLE;
106                 else
107                         inode->i_flags &= ~S_IMMUTABLE;
108         }
109 
110         fat_save_attrs(inode, attr);
111         mark_inode_dirty(inode);
112 out_unlock_inode:
113         inode_unlock(inode);
114         mnt_drop_write_file(file);
115 out:
116         return err;
117 }
118 
119 static int fat_ioctl_get_volume_id(struct inode *inode, u32 __user *user_attr)
120 {
121         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
122         return put_user(sbi->vol_id, user_attr);
123 }
124 
125 static int fat_ioctl_fitrim(struct inode *inode, unsigned long arg)
126 {
127         struct super_block *sb = inode->i_sb;
128         struct fstrim_range __user *user_range;
129         struct fstrim_range range;
130         struct request_queue *q = bdev_get_queue(sb->s_bdev);
131         int err;
132 
133         if (!capable(CAP_SYS_ADMIN))
134                 return -EPERM;
135 
136         if (!blk_queue_discard(q))
137                 return -EOPNOTSUPP;
138 
139         user_range = (struct fstrim_range __user *)arg;
140         if (copy_from_user(&range, user_range, sizeof(range)))
141                 return -EFAULT;
142 
143         range.minlen = max_t(unsigned int, range.minlen,
144                              q->limits.discard_granularity);
145 
146         err = fat_trim_fs(inode, &range);
147         if (err < 0)
148                 return err;
149 
150         if (copy_to_user(user_range, &range, sizeof(range)))
151                 return -EFAULT;
152 
153         return 0;
154 }
155 
156 long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
157 {
158         struct inode *inode = file_inode(filp);
159         u32 __user *user_attr = (u32 __user *)arg;
160 
161         switch (cmd) {
162         case FAT_IOCTL_GET_ATTRIBUTES:
163                 return fat_ioctl_get_attributes(inode, user_attr);
164         case FAT_IOCTL_SET_ATTRIBUTES:
165                 return fat_ioctl_set_attributes(filp, user_attr);
166         case FAT_IOCTL_GET_VOLUME_ID:
167                 return fat_ioctl_get_volume_id(inode, user_attr);
168         case FITRIM:
169                 return fat_ioctl_fitrim(inode, arg);
170         default:
171                 return -ENOTTY; /* Inappropriate ioctl for device */
172         }
173 }
174 
175 #ifdef CONFIG_COMPAT
176 static long fat_generic_compat_ioctl(struct file *filp, unsigned int cmd,
177                                       unsigned long arg)
178 
179 {
180         return fat_generic_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
181 }
182 #endif
183 
184 static int fat_file_release(struct inode *inode, struct file *filp)
185 {
186         if ((filp->f_mode & FMODE_WRITE) &&
187              MSDOS_SB(inode->i_sb)->options.flush) {
188                 fat_flush_inodes(inode->i_sb, inode, NULL);
189                 congestion_wait(BLK_RW_ASYNC, HZ/10);
190         }
191         return 0;
192 }
193 
194 int fat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
195 {
196         struct inode *inode = filp->f_mapping->host;
197         int err;
198 
199         err = __generic_file_fsync(filp, start, end, datasync);
200         if (err)
201                 return err;
202 
203         err = sync_mapping_buffers(MSDOS_SB(inode->i_sb)->fat_inode->i_mapping);
204         if (err)
205                 return err;
206 
207         return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
208 }
209 
210 
211 const struct file_operations fat_file_operations = {
212         .llseek         = generic_file_llseek,
213         .read_iter      = generic_file_read_iter,
214         .write_iter     = generic_file_write_iter,
215         .mmap           = generic_file_mmap,
216         .release        = fat_file_release,
217         .unlocked_ioctl = fat_generic_ioctl,
218 #ifdef CONFIG_COMPAT
219         .compat_ioctl   = fat_generic_compat_ioctl,
220 #endif
221         .fsync          = fat_file_fsync,
222         .splice_read    = generic_file_splice_read,
223         .splice_write   = iter_file_splice_write,
224         .fallocate      = fat_fallocate,
225 };
226 
227 static int fat_cont_expand(struct inode *inode, loff_t size)
228 {
229         struct address_space *mapping = inode->i_mapping;
230         loff_t start = inode->i_size, count = size - inode->i_size;
231         int err;
232 
233         err = generic_cont_expand_simple(inode, size);
234         if (err)
235                 goto out;
236 
237         fat_truncate_time(inode, NULL, S_CTIME|S_MTIME);
238         mark_inode_dirty(inode);
239         if (IS_SYNC(inode)) {
240                 int err2;
241 
242                 /*
243                  * Opencode syncing since we don't have a file open to use
244                  * standard fsync path.
245                  */
246                 err = filemap_fdatawrite_range(mapping, start,
247                                                start + count - 1);
248                 err2 = sync_mapping_buffers(mapping);
249                 if (!err)
250                         err = err2;
251                 err2 = write_inode_now(inode, 1);
252                 if (!err)
253                         err = err2;
254                 if (!err) {
255                         err =  filemap_fdatawait_range(mapping, start,
256                                                        start + count - 1);
257                 }
258         }
259 out:
260         return err;
261 }
262 
263 /*
264  * Preallocate space for a file. This implements fat's fallocate file
265  * operation, which gets called from sys_fallocate system call. User
266  * space requests len bytes at offset. If FALLOC_FL_KEEP_SIZE is set
267  * we just allocate clusters without zeroing them out. Otherwise we
268  * allocate and zero out clusters via an expanding truncate.
269  */
270 static long fat_fallocate(struct file *file, int mode,
271                           loff_t offset, loff_t len)
272 {
273         int nr_cluster; /* Number of clusters to be allocated */
274         loff_t mm_bytes; /* Number of bytes to be allocated for file */
275         loff_t ondisksize; /* block aligned on-disk size in bytes*/
276         struct inode *inode = file->f_mapping->host;
277         struct super_block *sb = inode->i_sb;
278         struct msdos_sb_info *sbi = MSDOS_SB(sb);
279         int err = 0;
280 
281         /* No support for hole punch or other fallocate flags. */
282         if (mode & ~FALLOC_FL_KEEP_SIZE)
283                 return -EOPNOTSUPP;
284 
285         /* No support for dir */
286         if (!S_ISREG(inode->i_mode))
287                 return -EOPNOTSUPP;
288 
289         inode_lock(inode);
290         if (mode & FALLOC_FL_KEEP_SIZE) {
291                 ondisksize = inode->i_blocks << 9;
292                 if ((offset + len) <= ondisksize)
293                         goto error;
294 
295                 /* First compute the number of clusters to be allocated */
296                 mm_bytes = offset + len - ondisksize;
297                 nr_cluster = (mm_bytes + (sbi->cluster_size - 1)) >>
298                         sbi->cluster_bits;
299 
300                 /* Start the allocation.We are not zeroing out the clusters */
301                 while (nr_cluster-- > 0) {
302                         err = fat_add_cluster(inode);
303                         if (err)
304                                 goto error;
305                 }
306         } else {
307                 if ((offset + len) <= i_size_read(inode))
308                         goto error;
309 
310                 /* This is just an expanding truncate */
311                 err = fat_cont_expand(inode, (offset + len));
312         }
313 
314 error:
315         inode_unlock(inode);
316         return err;
317 }
318 
319 /* Free all clusters after the skip'th cluster. */
320 static int fat_free(struct inode *inode, int skip)
321 {
322         struct super_block *sb = inode->i_sb;
323         int err, wait, free_start, i_start, i_logstart;
324 
325         if (MSDOS_I(inode)->i_start == 0)
326                 return 0;
327 
328         fat_cache_inval_inode(inode);
329 
330         wait = IS_DIRSYNC(inode);
331         i_start = free_start = MSDOS_I(inode)->i_start;
332         i_logstart = MSDOS_I(inode)->i_logstart;
333 
334         /* First, we write the new file size. */
335         if (!skip) {
336                 MSDOS_I(inode)->i_start = 0;
337                 MSDOS_I(inode)->i_logstart = 0;
338         }
339         MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
340         fat_truncate_time(inode, NULL, S_CTIME|S_MTIME);
341         if (wait) {
342                 err = fat_sync_inode(inode);
343                 if (err) {
344                         MSDOS_I(inode)->i_start = i_start;
345                         MSDOS_I(inode)->i_logstart = i_logstart;
346                         return err;
347                 }
348         } else
349                 mark_inode_dirty(inode);
350 
351         /* Write a new EOF, and get the remaining cluster chain for freeing. */
352         if (skip) {
353                 struct fat_entry fatent;
354                 int ret, fclus, dclus;
355 
356                 ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus);
357                 if (ret < 0)
358                         return ret;
359                 else if (ret == FAT_ENT_EOF)
360                         return 0;
361 
362                 fatent_init(&fatent);
363                 ret = fat_ent_read(inode, &fatent, dclus);
364                 if (ret == FAT_ENT_EOF) {
365                         fatent_brelse(&fatent);
366                         return 0;
367                 } else if (ret == FAT_ENT_FREE) {
368                         fat_fs_error(sb,
369                                      "%s: invalid cluster chain (i_pos %lld)",
370                                      __func__, MSDOS_I(inode)->i_pos);
371                         ret = -EIO;
372                 } else if (ret > 0) {
373                         err = fat_ent_write(inode, &fatent, FAT_ENT_EOF, wait);
374                         if (err)
375                                 ret = err;
376                 }
377                 fatent_brelse(&fatent);
378                 if (ret < 0)
379                         return ret;
380 
381                 free_start = ret;
382         }
383         inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9);
384 
385         /* Freeing the remained cluster chain */
386         return fat_free_clusters(inode, free_start);
387 }
388 
389 void fat_truncate_blocks(struct inode *inode, loff_t offset)
390 {
391         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
392         const unsigned int cluster_size = sbi->cluster_size;
393         int nr_clusters;
394 
395         /*
396          * This protects against truncating a file bigger than it was then
397          * trying to write into the hole.
398          */
399         if (MSDOS_I(inode)->mmu_private > offset)
400                 MSDOS_I(inode)->mmu_private = offset;
401 
402         nr_clusters = (offset + (cluster_size - 1)) >> sbi->cluster_bits;
403 
404         fat_free(inode, nr_clusters);
405         fat_flush_inodes(inode->i_sb, inode, NULL);
406 }
407 
408 int fat_getattr(const struct path *path, struct kstat *stat,
409                 u32 request_mask, unsigned int flags)
410 {
411         struct inode *inode = d_inode(path->dentry);
412         generic_fillattr(inode, stat);
413         stat->blksize = MSDOS_SB(inode->i_sb)->cluster_size;
414 
415         if (MSDOS_SB(inode->i_sb)->options.nfs == FAT_NFS_NOSTALE_RO) {
416                 /* Use i_pos for ino. This is used as fileid of nfs. */
417                 stat->ino = fat_i_pos_read(MSDOS_SB(inode->i_sb), inode);
418         }
419         return 0;
420 }
421 EXPORT_SYMBOL_GPL(fat_getattr);
422 
423 static int fat_sanitize_mode(const struct msdos_sb_info *sbi,
424                              struct inode *inode, umode_t *mode_ptr)
425 {
426         umode_t mask, perm;
427 
428         /*
429          * Note, the basic check is already done by a caller of
430          * (attr->ia_mode & ~FAT_VALID_MODE)
431          */
432 
433         if (S_ISREG(inode->i_mode))
434                 mask = sbi->options.fs_fmask;
435         else
436                 mask = sbi->options.fs_dmask;
437 
438         perm = *mode_ptr & ~(S_IFMT | mask);
439 
440         /*
441          * Of the r and x bits, all (subject to umask) must be present. Of the
442          * w bits, either all (subject to umask) or none must be present.
443          *
444          * If fat_mode_can_hold_ro(inode) is false, can't change w bits.
445          */
446         if ((perm & (S_IRUGO | S_IXUGO)) != (inode->i_mode & (S_IRUGO|S_IXUGO)))
447                 return -EPERM;
448         if (fat_mode_can_hold_ro(inode)) {
449                 if ((perm & S_IWUGO) && ((perm & S_IWUGO) != (S_IWUGO & ~mask)))
450                         return -EPERM;
451         } else {
452                 if ((perm & S_IWUGO) != (S_IWUGO & ~mask))
453                         return -EPERM;
454         }
455 
456         *mode_ptr &= S_IFMT | perm;
457 
458         return 0;
459 }
460 
461 static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode)
462 {
463         umode_t allow_utime = sbi->options.allow_utime;
464 
465         if (!uid_eq(current_fsuid(), inode->i_uid)) {
466                 if (in_group_p(inode->i_gid))
467                         allow_utime >>= 3;
468                 if (allow_utime & MAY_WRITE)
469                         return 1;
470         }
471 
472         /* use a default check */
473         return 0;
474 }
475 
476 #define TIMES_SET_FLAGS (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)
477 /* valid file mode bits */
478 #define FAT_VALID_MODE  (S_IFREG | S_IFDIR | S_IRWXUGO)
479 
480 int fat_setattr(struct dentry *dentry, struct iattr *attr)
481 {
482         struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
483         struct inode *inode = d_inode(dentry);
484         unsigned int ia_valid;
485         int error;
486 
487         /* Check for setting the inode time. */
488         ia_valid = attr->ia_valid;
489         if (ia_valid & TIMES_SET_FLAGS) {
490                 if (fat_allow_set_time(sbi, inode))
491                         attr->ia_valid &= ~TIMES_SET_FLAGS;
492         }
493 
494         error = setattr_prepare(dentry, attr);
495         attr->ia_valid = ia_valid;
496         if (error) {
497                 if (sbi->options.quiet)
498                         error = 0;
499                 goto out;
500         }
501 
502         /*
503          * Expand the file. Since inode_setattr() updates ->i_size
504          * before calling the ->truncate(), but FAT needs to fill the
505          * hole before it. XXX: this is no longer true with new truncate
506          * sequence.
507          */
508         if (attr->ia_valid & ATTR_SIZE) {
509                 inode_dio_wait(inode);
510 
511                 if (attr->ia_size > inode->i_size) {
512                         error = fat_cont_expand(inode, attr->ia_size);
513                         if (error || attr->ia_valid == ATTR_SIZE)
514                                 goto out;
515                         attr->ia_valid &= ~ATTR_SIZE;
516                 }
517         }
518 
519         if (((attr->ia_valid & ATTR_UID) &&
520              (!uid_eq(attr->ia_uid, sbi->options.fs_uid))) ||
521             ((attr->ia_valid & ATTR_GID) &&
522              (!gid_eq(attr->ia_gid, sbi->options.fs_gid))) ||
523             ((attr->ia_valid & ATTR_MODE) &&
524              (attr->ia_mode & ~FAT_VALID_MODE)))
525                 error = -EPERM;
526 
527         if (error) {
528                 if (sbi->options.quiet)
529                         error = 0;
530                 goto out;
531         }
532 
533         /*
534          * We don't return -EPERM here. Yes, strange, but this is too
535          * old behavior.
536          */
537         if (attr->ia_valid & ATTR_MODE) {
538                 if (fat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
539                         attr->ia_valid &= ~ATTR_MODE;
540         }
541 
542         if (attr->ia_valid & ATTR_SIZE) {
543                 error = fat_block_truncate_page(inode, attr->ia_size);
544                 if (error)
545                         goto out;
546                 down_write(&MSDOS_I(inode)->truncate_lock);
547                 truncate_setsize(inode, attr->ia_size);
548                 fat_truncate_blocks(inode, attr->ia_size);
549                 up_write(&MSDOS_I(inode)->truncate_lock);
550         }
551 
552         /*
553          * setattr_copy can't truncate these appropriately, so we'll
554          * copy them ourselves
555          */
556         if (attr->ia_valid & ATTR_ATIME)
557                 fat_truncate_time(inode, &attr->ia_atime, S_ATIME);
558         if (attr->ia_valid & ATTR_CTIME)
559                 fat_truncate_time(inode, &attr->ia_ctime, S_CTIME);
560         if (attr->ia_valid & ATTR_MTIME)
561                 fat_truncate_time(inode, &attr->ia_mtime, S_MTIME);
562         attr->ia_valid &= ~(ATTR_ATIME|ATTR_CTIME|ATTR_MTIME);
563 
564         setattr_copy(inode, attr);
565         mark_inode_dirty(inode);
566 out:
567         return error;
568 }
569 EXPORT_SYMBOL_GPL(fat_setattr);
570 
571 const struct inode_operations fat_file_inode_operations = {
572         .setattr        = fat_setattr,
573         .getattr        = fat_getattr,
574         .update_time    = fat_update_time,
575 };
576 

~ [ 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