Commit | Line | Data |
---|---|---|
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> |
42a74f20 | 11 | #include <linux/mount.h> |
1da177e4 | 12 | #include <linux/time.h> |
1da177e4 | 13 | #include <linux/buffer_head.h> |
05eb0b51 | 14 | #include <linux/writeback.h> |
3fcfab16 | 15 | #include <linux/backing-dev.h> |
ae78bf9c | 16 | #include <linux/blkdev.h> |
b1da47e2 MS |
17 | #include <linux/fsnotify.h> |
18 | #include <linux/security.h> | |
9e975dae | 19 | #include "fat.h" |
1da177e4 | 20 | |
1da177e4 LT |
21 | int fat_generic_ioctl(struct inode *inode, struct file *filp, |
22 | unsigned int cmd, unsigned long arg) | |
23 | { | |
24 | struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); | |
25 | u32 __user *user_attr = (u32 __user *)arg; | |
26 | ||
27 | switch (cmd) { | |
28 | case FAT_IOCTL_GET_ATTRIBUTES: | |
29 | { | |
9183482f OH |
30 | u32 attr; |
31 | ||
32 | mutex_lock(&inode->i_mutex); | |
33 | attr = fat_make_attrs(inode); | |
34 | mutex_unlock(&inode->i_mutex); | |
35 | ||
1da177e4 LT |
36 | return put_user(attr, user_attr); |
37 | } | |
38 | case FAT_IOCTL_SET_ATTRIBUTES: | |
39 | { | |
40 | u32 attr, oldattr; | |
41 | int err, is_dir = S_ISDIR(inode->i_mode); | |
42 | struct iattr ia; | |
43 | ||
44 | err = get_user(attr, user_attr); | |
45 | if (err) | |
46 | return err; | |
47 | ||
1b1dcc1b | 48 | mutex_lock(&inode->i_mutex); |
1da177e4 | 49 | |
42a74f20 DH |
50 | err = mnt_want_write(filp->f_path.mnt); |
51 | if (err) | |
52 | goto up_no_drop_write; | |
1da177e4 LT |
53 | |
54 | /* | |
55 | * ATTR_VOLUME and ATTR_DIR cannot be changed; this also | |
56 | * prevents the user from turning us into a VFAT | |
57 | * longname entry. Also, we obviously can't set | |
58 | * any of the NTFS attributes in the high 24 bits. | |
59 | */ | |
60 | attr &= 0xff & ~(ATTR_VOLUME | ATTR_DIR); | |
61 | /* Merge in ATTR_VOLUME and ATTR_DIR */ | |
62 | attr |= (MSDOS_I(inode)->i_attrs & ATTR_VOLUME) | | |
63 | (is_dir ? ATTR_DIR : 0); | |
9c0aa1b8 | 64 | oldattr = fat_make_attrs(inode); |
1da177e4 LT |
65 | |
66 | /* Equivalent to a chmod() */ | |
67 | ia.ia_valid = ATTR_MODE | ATTR_CTIME; | |
b1da47e2 | 68 | ia.ia_ctime = current_fs_time(inode->i_sb); |
9c0aa1b8 OH |
69 | if (is_dir) |
70 | ia.ia_mode = fat_make_mode(sbi, attr, S_IRWXUGO); | |
71 | else { | |
72 | ia.ia_mode = fat_make_mode(sbi, attr, | |
73 | S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO)); | |
1da177e4 LT |
74 | } |
75 | ||
76 | /* The root directory has no attributes */ | |
77 | if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) { | |
78 | err = -EINVAL; | |
79 | goto up; | |
80 | } | |
81 | ||
82 | if (sbi->options.sys_immutable) { | |
83 | if ((attr | oldattr) & ATTR_SYS) { | |
84 | if (!capable(CAP_LINUX_IMMUTABLE)) { | |
85 | err = -EPERM; | |
86 | goto up; | |
87 | } | |
88 | } | |
89 | } | |
90 | ||
b1da47e2 MS |
91 | /* |
92 | * The security check is questionable... We single | |
93 | * out the RO attribute for checking by the security | |
94 | * module, just because it maps to a file mode. | |
95 | */ | |
96 | err = security_inode_setattr(filp->f_path.dentry, &ia); | |
97 | if (err) | |
98 | goto up; | |
99 | ||
1da177e4 | 100 | /* This MUST be done before doing anything irreversible... */ |
b1da47e2 | 101 | err = fat_setattr(filp->f_path.dentry, &ia); |
1da177e4 LT |
102 | if (err) |
103 | goto up; | |
104 | ||
b1da47e2 | 105 | fsnotify_change(filp->f_path.dentry, ia.ia_valid); |
1da177e4 LT |
106 | if (sbi->options.sys_immutable) { |
107 | if (attr & ATTR_SYS) | |
108 | inode->i_flags |= S_IMMUTABLE; | |
109 | else | |
110 | inode->i_flags &= S_IMMUTABLE; | |
111 | } | |
112 | ||
9c0aa1b8 | 113 | fat_save_attrs(inode, attr); |
1da177e4 | 114 | mark_inode_dirty(inode); |
42a74f20 DH |
115 | up: |
116 | mnt_drop_write(filp->f_path.mnt); | |
117 | up_no_drop_write: | |
1b1dcc1b | 118 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
119 | return err; |
120 | } | |
121 | default: | |
122 | return -ENOTTY; /* Inappropriate ioctl for device */ | |
123 | } | |
124 | } | |
125 | ||
ae78bf9c CM |
126 | static int fat_file_release(struct inode *inode, struct file *filp) |
127 | { | |
128 | if ((filp->f_mode & FMODE_WRITE) && | |
129 | MSDOS_SB(inode->i_sb)->options.flush) { | |
130 | fat_flush_inodes(inode->i_sb, inode, NULL); | |
3fcfab16 | 131 | congestion_wait(WRITE, HZ/10); |
ae78bf9c CM |
132 | } |
133 | return 0; | |
134 | } | |
135 | ||
4b6f5d20 | 136 | const struct file_operations fat_file_operations = { |
1da177e4 LT |
137 | .llseek = generic_file_llseek, |
138 | .read = do_sync_read, | |
139 | .write = do_sync_write, | |
1da177e4 | 140 | .aio_read = generic_file_aio_read, |
ef402268 | 141 | .aio_write = generic_file_aio_write, |
1da177e4 | 142 | .mmap = generic_file_mmap, |
ae78bf9c | 143 | .release = fat_file_release, |
1da177e4 LT |
144 | .ioctl = fat_generic_ioctl, |
145 | .fsync = file_fsync, | |
5ffc4ef4 | 146 | .splice_read = generic_file_splice_read, |
1da177e4 LT |
147 | }; |
148 | ||
05eb0b51 OH |
149 | static int fat_cont_expand(struct inode *inode, loff_t size) |
150 | { | |
151 | struct address_space *mapping = inode->i_mapping; | |
152 | loff_t start = inode->i_size, count = size - inode->i_size; | |
153 | int err; | |
154 | ||
155 | err = generic_cont_expand_simple(inode, size); | |
156 | if (err) | |
157 | goto out; | |
158 | ||
159 | inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; | |
160 | mark_inode_dirty(inode); | |
161 | if (IS_SYNC(inode)) | |
162 | err = sync_page_range_nolock(inode, mapping, start, count); | |
163 | out: | |
164 | return err; | |
165 | } | |
166 | ||
1da177e4 LT |
167 | /* Free all clusters after the skip'th cluster. */ |
168 | static int fat_free(struct inode *inode, int skip) | |
169 | { | |
170 | struct super_block *sb = inode->i_sb; | |
171 | int err, wait, free_start, i_start, i_logstart; | |
172 | ||
173 | if (MSDOS_I(inode)->i_start == 0) | |
174 | return 0; | |
175 | ||
3b641407 OH |
176 | fat_cache_inval_inode(inode); |
177 | ||
1da177e4 | 178 | wait = IS_DIRSYNC(inode); |
3b641407 OH |
179 | i_start = free_start = MSDOS_I(inode)->i_start; |
180 | i_logstart = MSDOS_I(inode)->i_logstart; | |
181 | ||
182 | /* First, we write the new file size. */ | |
183 | if (!skip) { | |
184 | MSDOS_I(inode)->i_start = 0; | |
185 | MSDOS_I(inode)->i_logstart = 0; | |
186 | } | |
187 | MSDOS_I(inode)->i_attrs |= ATTR_ARCH; | |
188 | inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; | |
189 | if (wait) { | |
190 | err = fat_sync_inode(inode); | |
191 | if (err) { | |
192 | MSDOS_I(inode)->i_start = i_start; | |
193 | MSDOS_I(inode)->i_logstart = i_logstart; | |
194 | return err; | |
195 | } | |
196 | } else | |
197 | mark_inode_dirty(inode); | |
198 | ||
199 | /* Write a new EOF, and get the remaining cluster chain for freeing. */ | |
1da177e4 LT |
200 | if (skip) { |
201 | struct fat_entry fatent; | |
202 | int ret, fclus, dclus; | |
203 | ||
204 | ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus); | |
205 | if (ret < 0) | |
206 | return ret; | |
207 | else if (ret == FAT_ENT_EOF) | |
208 | return 0; | |
209 | ||
210 | fatent_init(&fatent); | |
211 | ret = fat_ent_read(inode, &fatent, dclus); | |
212 | if (ret == FAT_ENT_EOF) { | |
213 | fatent_brelse(&fatent); | |
214 | return 0; | |
215 | } else if (ret == FAT_ENT_FREE) { | |
216 | fat_fs_panic(sb, | |
217 | "%s: invalid cluster chain (i_pos %lld)", | |
8e24eea7 | 218 | __func__, MSDOS_I(inode)->i_pos); |
1da177e4 LT |
219 | ret = -EIO; |
220 | } else if (ret > 0) { | |
221 | err = fat_ent_write(inode, &fatent, FAT_ENT_EOF, wait); | |
222 | if (err) | |
223 | ret = err; | |
224 | } | |
225 | fatent_brelse(&fatent); | |
226 | if (ret < 0) | |
227 | return ret; | |
228 | ||
229 | free_start = ret; | |
1da177e4 | 230 | } |
1da177e4 LT |
231 | inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9); |
232 | ||
233 | /* Freeing the remained cluster chain */ | |
234 | return fat_free_clusters(inode, free_start); | |
1da177e4 LT |
235 | } |
236 | ||
237 | void fat_truncate(struct inode *inode) | |
238 | { | |
9c20616c | 239 | struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); |
1da177e4 LT |
240 | const unsigned int cluster_size = sbi->cluster_size; |
241 | int nr_clusters; | |
242 | ||
243 | /* | |
244 | * This protects against truncating a file bigger than it was then | |
245 | * trying to write into the hole. | |
246 | */ | |
247 | if (MSDOS_I(inode)->mmu_private > inode->i_size) | |
248 | MSDOS_I(inode)->mmu_private = inode->i_size; | |
249 | ||
250 | nr_clusters = (inode->i_size + (cluster_size - 1)) >> sbi->cluster_bits; | |
251 | ||
1da177e4 | 252 | fat_free(inode, nr_clusters); |
ae78bf9c | 253 | fat_flush_inodes(inode->i_sb, inode, NULL); |
1da177e4 LT |
254 | } |
255 | ||
da63fc7c OH |
256 | int fat_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) |
257 | { | |
258 | struct inode *inode = dentry->d_inode; | |
259 | generic_fillattr(inode, stat); | |
260 | stat->blksize = MSDOS_SB(inode->i_sb)->cluster_size; | |
261 | return 0; | |
262 | } | |
263 | EXPORT_SYMBOL_GPL(fat_getattr); | |
264 | ||
2d518f84 OH |
265 | static int fat_sanitize_mode(const struct msdos_sb_info *sbi, |
266 | struct inode *inode, umode_t *mode_ptr) | |
1278fdd3 | 267 | { |
2d518f84 | 268 | mode_t mask, perm; |
1278fdd3 | 269 | |
2d518f84 OH |
270 | /* |
271 | * Note, the basic check is already done by a caller of | |
9c0aa1b8 | 272 | * (attr->ia_mode & ~FAT_VALID_MODE) |
2d518f84 OH |
273 | */ |
274 | ||
275 | if (S_ISREG(inode->i_mode)) | |
1278fdd3 OH |
276 | mask = sbi->options.fs_fmask; |
277 | else | |
278 | mask = sbi->options.fs_dmask; | |
279 | ||
2d518f84 OH |
280 | perm = *mode_ptr & ~(S_IFMT | mask); |
281 | ||
1278fdd3 OH |
282 | /* |
283 | * Of the r and x bits, all (subject to umask) must be present. Of the | |
284 | * w bits, either all (subject to umask) or none must be present. | |
dfc209c0 OH |
285 | * |
286 | * If fat_mode_can_hold_ro(inode) is false, can't change w bits. | |
1278fdd3 | 287 | */ |
2d518f84 | 288 | if ((perm & (S_IRUGO | S_IXUGO)) != (inode->i_mode & (S_IRUGO|S_IXUGO))) |
1278fdd3 | 289 | return -EPERM; |
dfc209c0 OH |
290 | if (fat_mode_can_hold_ro(inode)) { |
291 | if ((perm & S_IWUGO) && ((perm & S_IWUGO) != (S_IWUGO & ~mask))) | |
292 | return -EPERM; | |
293 | } else { | |
294 | if ((perm & S_IWUGO) != (S_IWUGO & ~mask)) | |
295 | return -EPERM; | |
296 | } | |
1278fdd3 | 297 | |
2d518f84 OH |
298 | *mode_ptr &= S_IFMT | perm; |
299 | ||
1278fdd3 OH |
300 | return 0; |
301 | } | |
302 | ||
1ae43f82 OH |
303 | static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode) |
304 | { | |
305 | mode_t allow_utime = sbi->options.allow_utime; | |
306 | ||
307 | if (current->fsuid != inode->i_uid) { | |
308 | if (in_group_p(inode->i_gid)) | |
309 | allow_utime >>= 3; | |
310 | if (allow_utime & MAY_WRITE) | |
311 | return 1; | |
312 | } | |
313 | ||
314 | /* use a default check */ | |
315 | return 0; | |
316 | } | |
317 | ||
17263849 | 318 | #define TIMES_SET_FLAGS (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET) |
9c0aa1b8 OH |
319 | /* valid file mode bits */ |
320 | #define FAT_VALID_MODE (S_IFREG | S_IFDIR | S_IRWXUGO) | |
17263849 | 321 | |
1278fdd3 OH |
322 | int fat_setattr(struct dentry *dentry, struct iattr *attr) |
323 | { | |
324 | struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb); | |
325 | struct inode *inode = dentry->d_inode; | |
1ae43f82 | 326 | unsigned int ia_valid; |
dfc209c0 | 327 | int error; |
1278fdd3 | 328 | |
1278fdd3 OH |
329 | /* |
330 | * Expand the file. Since inode_setattr() updates ->i_size | |
331 | * before calling the ->truncate(), but FAT needs to fill the | |
332 | * hole before it. | |
333 | */ | |
334 | if (attr->ia_valid & ATTR_SIZE) { | |
335 | if (attr->ia_size > inode->i_size) { | |
336 | error = fat_cont_expand(inode, attr->ia_size); | |
337 | if (error || attr->ia_valid == ATTR_SIZE) | |
338 | goto out; | |
339 | attr->ia_valid &= ~ATTR_SIZE; | |
340 | } | |
341 | } | |
342 | ||
1ae43f82 OH |
343 | /* Check for setting the inode time. */ |
344 | ia_valid = attr->ia_valid; | |
17263849 | 345 | if (ia_valid & TIMES_SET_FLAGS) { |
1ae43f82 | 346 | if (fat_allow_set_time(sbi, inode)) |
17263849 | 347 | attr->ia_valid &= ~TIMES_SET_FLAGS; |
1ae43f82 OH |
348 | } |
349 | ||
1278fdd3 | 350 | error = inode_change_ok(inode, attr); |
1ae43f82 | 351 | attr->ia_valid = ia_valid; |
1278fdd3 OH |
352 | if (error) { |
353 | if (sbi->options.quiet) | |
354 | error = 0; | |
355 | goto out; | |
356 | } | |
2d518f84 | 357 | |
1278fdd3 OH |
358 | if (((attr->ia_valid & ATTR_UID) && |
359 | (attr->ia_uid != sbi->options.fs_uid)) || | |
360 | ((attr->ia_valid & ATTR_GID) && | |
e97e8de3 OH |
361 | (attr->ia_gid != sbi->options.fs_gid)) || |
362 | ((attr->ia_valid & ATTR_MODE) && | |
9c0aa1b8 | 363 | (attr->ia_mode & ~FAT_VALID_MODE))) |
1278fdd3 OH |
364 | error = -EPERM; |
365 | ||
366 | if (error) { | |
367 | if (sbi->options.quiet) | |
368 | error = 0; | |
369 | goto out; | |
370 | } | |
371 | ||
2d518f84 OH |
372 | /* |
373 | * We don't return -EPERM here. Yes, strange, but this is too | |
374 | * old behavior. | |
375 | */ | |
376 | if (attr->ia_valid & ATTR_MODE) { | |
377 | if (fat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0) | |
378 | attr->ia_valid &= ~ATTR_MODE; | |
379 | } | |
1278fdd3 | 380 | |
dfc209c0 OH |
381 | if (attr->ia_valid) |
382 | error = inode_setattr(inode, attr); | |
1278fdd3 | 383 | out: |
1278fdd3 OH |
384 | return error; |
385 | } | |
386 | EXPORT_SYMBOL_GPL(fat_setattr); | |
387 | ||
754661f1 | 388 | const struct inode_operations fat_file_inode_operations = { |
1da177e4 | 389 | .truncate = fat_truncate, |
1278fdd3 | 390 | .setattr = fat_setattr, |
da63fc7c | 391 | .getattr = fat_getattr, |
1da177e4 | 392 | }; |