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CommitLineData
1da177e4
LT
1/*
2 * linux/fs/fat/file.c
3 *
4 * Written 1992,1993 by Werner Almesberger
5 *
6 * regular file handling primitives for fat-based filesystems
7 */
8
16f7e0fe 9#include <linux/capability.h>
1da177e4 10#include <linux/module.h>
7845bc3e 11#include <linux/compat.h>
42a74f20 12#include <linux/mount.h>
1da177e4 13#include <linux/time.h>
1da177e4 14#include <linux/buffer_head.h>
05eb0b51 15#include <linux/writeback.h>
3fcfab16 16#include <linux/backing-dev.h>
ae78bf9c 17#include <linux/blkdev.h>
b1da47e2
MS
18#include <linux/fsnotify.h>
19#include <linux/security.h>
9e975dae 20#include "fat.h"
1da177e4 21
21bea495
CH
22static int fat_ioctl_get_attributes(struct inode *inode, u32 __user *user_attr)
23{
24 u32 attr;
25
26 mutex_lock(&inode->i_mutex);
27 attr = fat_make_attrs(inode);
28 mutex_unlock(&inode->i_mutex);
29
30 return put_user(attr, user_attr);
31}
32
33static int fat_ioctl_set_attributes(struct file *file, u32 __user *user_attr)
1da177e4 34{
496ad9aa 35 struct inode *inode = file_inode(file);
1da177e4 36 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
21bea495
CH
37 int is_dir = S_ISDIR(inode->i_mode);
38 u32 attr, oldattr;
39 struct iattr ia;
40 int err;
1da177e4 41
21bea495
CH
42 err = get_user(attr, user_attr);
43 if (err)
44 goto out;
1da177e4 45
a561be71 46 err = mnt_want_write_file(file);
21bea495 47 if (err)
e24f17da
JK
48 goto out;
49 mutex_lock(&inode->i_mutex);
21bea495
CH
50
51 /*
52 * ATTR_VOLUME and ATTR_DIR cannot be changed; this also
53 * prevents the user from turning us into a VFAT
54 * longname entry. Also, we obviously can't set
55 * any of the NTFS attributes in the high 24 bits.
56 */
57 attr &= 0xff & ~(ATTR_VOLUME | ATTR_DIR);
58 /* Merge in ATTR_VOLUME and ATTR_DIR */
59 attr |= (MSDOS_I(inode)->i_attrs & ATTR_VOLUME) |
60 (is_dir ? ATTR_DIR : 0);
61 oldattr = fat_make_attrs(inode);
62
63 /* Equivalent to a chmod() */
64 ia.ia_valid = ATTR_MODE | ATTR_CTIME;
65 ia.ia_ctime = current_fs_time(inode->i_sb);
66 if (is_dir)
67 ia.ia_mode = fat_make_mode(sbi, attr, S_IRWXUGO);
68 else {
69 ia.ia_mode = fat_make_mode(sbi, attr,
70 S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO));
71 }
1da177e4 72
21bea495
CH
73 /* The root directory has no attributes */
74 if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) {
75 err = -EINVAL;
e24f17da 76 goto out_unlock_inode;
1da177e4 77 }
1da177e4 78
21bea495
CH
79 if (sbi->options.sys_immutable &&
80 ((attr | oldattr) & ATTR_SYS) &&
81 !capable(CAP_LINUX_IMMUTABLE)) {
82 err = -EPERM;
e24f17da 83 goto out_unlock_inode;
21bea495 84 }
1da177e4 85
21bea495
CH
86 /*
87 * The security check is questionable... We single
88 * out the RO attribute for checking by the security
89 * module, just because it maps to a file mode.
90 */
91 err = security_inode_setattr(file->f_path.dentry, &ia);
92 if (err)
e24f17da 93 goto out_unlock_inode;
1da177e4 94
21bea495
CH
95 /* This MUST be done before doing anything irreversible... */
96 err = fat_setattr(file->f_path.dentry, &ia);
97 if (err)
e24f17da 98 goto out_unlock_inode;
21bea495
CH
99
100 fsnotify_change(file->f_path.dentry, ia.ia_valid);
101 if (sbi->options.sys_immutable) {
102 if (attr & ATTR_SYS)
103 inode->i_flags |= S_IMMUTABLE;
104 else
1adffbae 105 inode->i_flags &= ~S_IMMUTABLE;
21bea495 106 }
1da177e4 107
21bea495
CH
108 fat_save_attrs(inode, attr);
109 mark_inode_dirty(inode);
21bea495
CH
110out_unlock_inode:
111 mutex_unlock(&inode->i_mutex);
e24f17da 112 mnt_drop_write_file(file);
21bea495
CH
113out:
114 return err;
115}
1da177e4 116
6e5b93ee
ML
117static int fat_ioctl_get_volume_id(struct inode *inode, u32 __user *user_attr)
118{
119 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
120 return put_user(sbi->vol_id, user_attr);
121}
122
7845bc3e 123long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
1da177e4 124{
496ad9aa 125 struct inode *inode = file_inode(filp);
1da177e4 126 u32 __user *user_attr = (u32 __user *)arg;
1da177e4 127
1da177e4
LT
128 switch (cmd) {
129 case FAT_IOCTL_GET_ATTRIBUTES:
21bea495 130 return fat_ioctl_get_attributes(inode, user_attr);
1da177e4 131 case FAT_IOCTL_SET_ATTRIBUTES:
21bea495 132 return fat_ioctl_set_attributes(filp, user_attr);
6e5b93ee
ML
133 case FAT_IOCTL_GET_VOLUME_ID:
134 return fat_ioctl_get_volume_id(inode, user_attr);
1da177e4
LT
135 default:
136 return -ENOTTY; /* Inappropriate ioctl for device */
137 }
138}
139
7845bc3e
AB
140#ifdef CONFIG_COMPAT
141static long fat_generic_compat_ioctl(struct file *filp, unsigned int cmd,
142 unsigned long arg)
143
144{
145 return fat_generic_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
146}
147#endif
148
ae78bf9c
CM
149static int fat_file_release(struct inode *inode, struct file *filp)
150{
151 if ((filp->f_mode & FMODE_WRITE) &&
152 MSDOS_SB(inode->i_sb)->options.flush) {
153 fat_flush_inodes(inode->i_sb, inode, NULL);
8aa7e847 154 congestion_wait(BLK_RW_ASYNC, HZ/10);
ae78bf9c
CM
155 }
156 return 0;
157}
158
02c24a82 159int fat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
b522412a 160{
7ea80859 161 struct inode *inode = filp->f_mapping->host;
b522412a
AV
162 int res, err;
163
02c24a82 164 res = generic_file_fsync(filp, start, end, datasync);
b522412a
AV
165 err = sync_mapping_buffers(MSDOS_SB(inode->i_sb)->fat_inode->i_mapping);
166
167 return res ? res : err;
168}
169
170
4b6f5d20 171const struct file_operations fat_file_operations = {
1da177e4 172 .llseek = generic_file_llseek,
aad4f8bb 173 .read = new_sync_read,
8174202b 174 .write = new_sync_write,
aad4f8bb 175 .read_iter = generic_file_read_iter,
8174202b 176 .write_iter = generic_file_write_iter,
1da177e4 177 .mmap = generic_file_mmap,
ae78bf9c 178 .release = fat_file_release,
7845bc3e
AB
179 .unlocked_ioctl = fat_generic_ioctl,
180#ifdef CONFIG_COMPAT
181 .compat_ioctl = fat_generic_compat_ioctl,
182#endif
b522412a 183 .fsync = fat_file_fsync,
5ffc4ef4 184 .splice_read = generic_file_splice_read,
1da177e4
LT
185};
186
05eb0b51
OH
187static int fat_cont_expand(struct inode *inode, loff_t size)
188{
189 struct address_space *mapping = inode->i_mapping;
190 loff_t start = inode->i_size, count = size - inode->i_size;
191 int err;
192
193 err = generic_cont_expand_simple(inode, size);
194 if (err)
195 goto out;
196
197 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
198 mark_inode_dirty(inode);
2f3d675b
JK
199 if (IS_SYNC(inode)) {
200 int err2;
201
202 /*
203 * Opencode syncing since we don't have a file open to use
204 * standard fsync path.
205 */
206 err = filemap_fdatawrite_range(mapping, start,
207 start + count - 1);
208 err2 = sync_mapping_buffers(mapping);
209 if (!err)
210 err = err2;
211 err2 = write_inode_now(inode, 1);
212 if (!err)
213 err = err2;
214 if (!err) {
215 err = filemap_fdatawait_range(mapping, start,
216 start + count - 1);
217 }
218 }
05eb0b51
OH
219out:
220 return err;
221}
222
1da177e4
LT
223/* Free all clusters after the skip'th cluster. */
224static int fat_free(struct inode *inode, int skip)
225{
226 struct super_block *sb = inode->i_sb;
227 int err, wait, free_start, i_start, i_logstart;
228
229 if (MSDOS_I(inode)->i_start == 0)
230 return 0;
231
3b641407
OH
232 fat_cache_inval_inode(inode);
233
1da177e4 234 wait = IS_DIRSYNC(inode);
3b641407
OH
235 i_start = free_start = MSDOS_I(inode)->i_start;
236 i_logstart = MSDOS_I(inode)->i_logstart;
237
238 /* First, we write the new file size. */
239 if (!skip) {
240 MSDOS_I(inode)->i_start = 0;
241 MSDOS_I(inode)->i_logstart = 0;
242 }
243 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
244 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
245 if (wait) {
246 err = fat_sync_inode(inode);
247 if (err) {
248 MSDOS_I(inode)->i_start = i_start;
249 MSDOS_I(inode)->i_logstart = i_logstart;
250 return err;
251 }
252 } else
253 mark_inode_dirty(inode);
254
255 /* Write a new EOF, and get the remaining cluster chain for freeing. */
1da177e4
LT
256 if (skip) {
257 struct fat_entry fatent;
258 int ret, fclus, dclus;
259
260 ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus);
261 if (ret < 0)
262 return ret;
263 else if (ret == FAT_ENT_EOF)
264 return 0;
265
266 fatent_init(&fatent);
267 ret = fat_ent_read(inode, &fatent, dclus);
268 if (ret == FAT_ENT_EOF) {
269 fatent_brelse(&fatent);
270 return 0;
271 } else if (ret == FAT_ENT_FREE) {
85c78591 272 fat_fs_error(sb,
1da177e4 273 "%s: invalid cluster chain (i_pos %lld)",
8e24eea7 274 __func__, MSDOS_I(inode)->i_pos);
1da177e4
LT
275 ret = -EIO;
276 } else if (ret > 0) {
277 err = fat_ent_write(inode, &fatent, FAT_ENT_EOF, wait);
278 if (err)
279 ret = err;
280 }
281 fatent_brelse(&fatent);
282 if (ret < 0)
283 return ret;
284
285 free_start = ret;
1da177e4 286 }
1da177e4
LT
287 inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9);
288
289 /* Freeing the remained cluster chain */
290 return fat_free_clusters(inode, free_start);
1da177e4
LT
291}
292
459f6ed3 293void fat_truncate_blocks(struct inode *inode, loff_t offset)
1da177e4 294{
9c20616c 295 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
1da177e4
LT
296 const unsigned int cluster_size = sbi->cluster_size;
297 int nr_clusters;
298
299 /*
300 * This protects against truncating a file bigger than it was then
301 * trying to write into the hole.
302 */
459f6ed3 303 if (MSDOS_I(inode)->mmu_private > offset)
304 MSDOS_I(inode)->mmu_private = offset;
1da177e4 305
459f6ed3 306 nr_clusters = (offset + (cluster_size - 1)) >> sbi->cluster_bits;
1da177e4 307
1da177e4 308 fat_free(inode, nr_clusters);
ae78bf9c 309 fat_flush_inodes(inode->i_sb, inode, NULL);
1da177e4
LT
310}
311
da63fc7c
OH
312int fat_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
313{
314 struct inode *inode = dentry->d_inode;
315 generic_fillattr(inode, stat);
316 stat->blksize = MSDOS_SB(inode->i_sb)->cluster_size;
ea3983ac
NJ
317
318 if (MSDOS_SB(inode->i_sb)->options.nfs == FAT_NFS_NOSTALE_RO) {
319 /* Use i_pos for ino. This is used as fileid of nfs. */
320 stat->ino = fat_i_pos_read(MSDOS_SB(inode->i_sb), inode);
321 }
da63fc7c
OH
322 return 0;
323}
324EXPORT_SYMBOL_GPL(fat_getattr);
325
2d518f84
OH
326static int fat_sanitize_mode(const struct msdos_sb_info *sbi,
327 struct inode *inode, umode_t *mode_ptr)
1278fdd3 328{
dacd0e7b 329 umode_t mask, perm;
1278fdd3 330
2d518f84
OH
331 /*
332 * Note, the basic check is already done by a caller of
9c0aa1b8 333 * (attr->ia_mode & ~FAT_VALID_MODE)
2d518f84
OH
334 */
335
336 if (S_ISREG(inode->i_mode))
1278fdd3
OH
337 mask = sbi->options.fs_fmask;
338 else
339 mask = sbi->options.fs_dmask;
340
2d518f84
OH
341 perm = *mode_ptr & ~(S_IFMT | mask);
342
1278fdd3
OH
343 /*
344 * Of the r and x bits, all (subject to umask) must be present. Of the
345 * w bits, either all (subject to umask) or none must be present.
dfc209c0
OH
346 *
347 * If fat_mode_can_hold_ro(inode) is false, can't change w bits.
1278fdd3 348 */
2d518f84 349 if ((perm & (S_IRUGO | S_IXUGO)) != (inode->i_mode & (S_IRUGO|S_IXUGO)))
1278fdd3 350 return -EPERM;
dfc209c0
OH
351 if (fat_mode_can_hold_ro(inode)) {
352 if ((perm & S_IWUGO) && ((perm & S_IWUGO) != (S_IWUGO & ~mask)))
353 return -EPERM;
354 } else {
355 if ((perm & S_IWUGO) != (S_IWUGO & ~mask))
356 return -EPERM;
357 }
1278fdd3 358
2d518f84
OH
359 *mode_ptr &= S_IFMT | perm;
360
1278fdd3
OH
361 return 0;
362}
363
1ae43f82
OH
364static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode)
365{
dacd0e7b 366 umode_t allow_utime = sbi->options.allow_utime;
1ae43f82 367
170782eb 368 if (!uid_eq(current_fsuid(), inode->i_uid)) {
1ae43f82
OH
369 if (in_group_p(inode->i_gid))
370 allow_utime >>= 3;
371 if (allow_utime & MAY_WRITE)
372 return 1;
373 }
374
375 /* use a default check */
376 return 0;
377}
378
17263849 379#define TIMES_SET_FLAGS (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)
9c0aa1b8
OH
380/* valid file mode bits */
381#define FAT_VALID_MODE (S_IFREG | S_IFDIR | S_IRWXUGO)
17263849 382
1278fdd3
OH
383int fat_setattr(struct dentry *dentry, struct iattr *attr)
384{
385 struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
386 struct inode *inode = dentry->d_inode;
1ae43f82 387 unsigned int ia_valid;
dfc209c0 388 int error;
1278fdd3 389
1ae43f82
OH
390 /* Check for setting the inode time. */
391 ia_valid = attr->ia_valid;
17263849 392 if (ia_valid & TIMES_SET_FLAGS) {
1ae43f82 393 if (fat_allow_set_time(sbi, inode))
17263849 394 attr->ia_valid &= ~TIMES_SET_FLAGS;
1ae43f82
OH
395 }
396
1278fdd3 397 error = inode_change_ok(inode, attr);
1ae43f82 398 attr->ia_valid = ia_valid;
1278fdd3
OH
399 if (error) {
400 if (sbi->options.quiet)
401 error = 0;
402 goto out;
403 }
2d518f84 404
db78b877
CH
405 /*
406 * Expand the file. Since inode_setattr() updates ->i_size
407 * before calling the ->truncate(), but FAT needs to fill the
408 * hole before it. XXX: this is no longer true with new truncate
409 * sequence.
410 */
411 if (attr->ia_valid & ATTR_SIZE) {
562c72aa
CH
412 inode_dio_wait(inode);
413
db78b877
CH
414 if (attr->ia_size > inode->i_size) {
415 error = fat_cont_expand(inode, attr->ia_size);
416 if (error || attr->ia_valid == ATTR_SIZE)
417 goto out;
418 attr->ia_valid &= ~ATTR_SIZE;
419 }
420 }
421
1278fdd3 422 if (((attr->ia_valid & ATTR_UID) &&
170782eb 423 (!uid_eq(attr->ia_uid, sbi->options.fs_uid))) ||
1278fdd3 424 ((attr->ia_valid & ATTR_GID) &&
170782eb 425 (!gid_eq(attr->ia_gid, sbi->options.fs_gid))) ||
e97e8de3 426 ((attr->ia_valid & ATTR_MODE) &&
9c0aa1b8 427 (attr->ia_mode & ~FAT_VALID_MODE)))
1278fdd3
OH
428 error = -EPERM;
429
430 if (error) {
431 if (sbi->options.quiet)
432 error = 0;
433 goto out;
434 }
435
2d518f84
OH
436 /*
437 * We don't return -EPERM here. Yes, strange, but this is too
438 * old behavior.
439 */
440 if (attr->ia_valid & ATTR_MODE) {
441 if (fat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
442 attr->ia_valid &= ~ATTR_MODE;
443 }
1278fdd3 444
459f6ed3 445 if (attr->ia_valid & ATTR_SIZE) {
58268691 446 down_write(&MSDOS_I(inode)->truncate_lock);
2c27c65e
CH
447 truncate_setsize(inode, attr->ia_size);
448 fat_truncate_blocks(inode, attr->ia_size);
58268691 449 up_write(&MSDOS_I(inode)->truncate_lock);
459f6ed3 450 }
451
6a1a90ad 452 setattr_copy(inode, attr);
459f6ed3 453 mark_inode_dirty(inode);
1278fdd3 454out:
1278fdd3
OH
455 return error;
456}
457EXPORT_SYMBOL_GPL(fat_setattr);
458
754661f1 459const struct inode_operations fat_file_inode_operations = {
1278fdd3 460 .setattr = fat_setattr,
da63fc7c 461 .getattr = fat_getattr,
1da177e4 462};