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