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 LT |
12 | #include <linux/time.h> |
13 | #include <linux/msdos_fs.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> |
1da177e4 | 18 | |
1da177e4 LT |
19 | int fat_generic_ioctl(struct inode *inode, struct file *filp, |
20 | unsigned int cmd, unsigned long arg) | |
21 | { | |
22 | struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); | |
23 | u32 __user *user_attr = (u32 __user *)arg; | |
24 | ||
25 | switch (cmd) { | |
26 | case FAT_IOCTL_GET_ATTRIBUTES: | |
27 | { | |
28 | u32 attr; | |
29 | ||
30 | if (inode->i_ino == MSDOS_ROOT_INO) | |
31 | attr = ATTR_DIR; | |
32 | else | |
33 | attr = fat_attr(inode); | |
34 | ||
35 | return put_user(attr, user_attr); | |
36 | } | |
37 | case FAT_IOCTL_SET_ATTRIBUTES: | |
38 | { | |
39 | u32 attr, oldattr; | |
40 | int err, is_dir = S_ISDIR(inode->i_mode); | |
41 | struct iattr ia; | |
42 | ||
43 | err = get_user(attr, user_attr); | |
44 | if (err) | |
45 | return err; | |
46 | ||
1b1dcc1b | 47 | mutex_lock(&inode->i_mutex); |
1da177e4 | 48 | |
42a74f20 DH |
49 | err = mnt_want_write(filp->f_path.mnt); |
50 | if (err) | |
51 | goto up_no_drop_write; | |
1da177e4 LT |
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_attr(inode); | |
64 | ||
65 | /* Equivalent to a chmod() */ | |
66 | ia.ia_valid = ATTR_MODE | ATTR_CTIME; | |
67 | if (is_dir) { | |
68 | ia.ia_mode = MSDOS_MKMODE(attr, | |
69 | S_IRWXUGO & ~sbi->options.fs_dmask) | |
70 | | S_IFDIR; | |
71 | } else { | |
72 | ia.ia_mode = MSDOS_MKMODE(attr, | |
73 | (S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO)) | |
74 | & ~sbi->options.fs_fmask) | |
75 | | S_IFREG; | |
76 | } | |
77 | ||
78 | /* The root directory has no attributes */ | |
79 | if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) { | |
80 | err = -EINVAL; | |
81 | goto up; | |
82 | } | |
83 | ||
84 | if (sbi->options.sys_immutable) { | |
85 | if ((attr | oldattr) & ATTR_SYS) { | |
86 | if (!capable(CAP_LINUX_IMMUTABLE)) { | |
87 | err = -EPERM; | |
88 | goto up; | |
89 | } | |
90 | } | |
91 | } | |
92 | ||
93 | /* This MUST be done before doing anything irreversible... */ | |
dba32306 | 94 | err = notify_change(filp->f_path.dentry, &ia); |
1da177e4 LT |
95 | if (err) |
96 | goto up; | |
97 | ||
98 | if (sbi->options.sys_immutable) { | |
99 | if (attr & ATTR_SYS) | |
100 | inode->i_flags |= S_IMMUTABLE; | |
101 | else | |
102 | inode->i_flags &= S_IMMUTABLE; | |
103 | } | |
104 | ||
105 | MSDOS_I(inode)->i_attrs = attr & ATTR_UNUSED; | |
106 | mark_inode_dirty(inode); | |
42a74f20 DH |
107 | up: |
108 | mnt_drop_write(filp->f_path.mnt); | |
109 | up_no_drop_write: | |
1b1dcc1b | 110 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
111 | return err; |
112 | } | |
113 | default: | |
114 | return -ENOTTY; /* Inappropriate ioctl for device */ | |
115 | } | |
116 | } | |
117 | ||
ae78bf9c CM |
118 | static int fat_file_release(struct inode *inode, struct file *filp) |
119 | { | |
120 | if ((filp->f_mode & FMODE_WRITE) && | |
121 | MSDOS_SB(inode->i_sb)->options.flush) { | |
122 | fat_flush_inodes(inode->i_sb, inode, NULL); | |
3fcfab16 | 123 | congestion_wait(WRITE, HZ/10); |
ae78bf9c CM |
124 | } |
125 | return 0; | |
126 | } | |
127 | ||
4b6f5d20 | 128 | const struct file_operations fat_file_operations = { |
1da177e4 LT |
129 | .llseek = generic_file_llseek, |
130 | .read = do_sync_read, | |
131 | .write = do_sync_write, | |
1da177e4 | 132 | .aio_read = generic_file_aio_read, |
ef402268 | 133 | .aio_write = generic_file_aio_write, |
1da177e4 | 134 | .mmap = generic_file_mmap, |
ae78bf9c | 135 | .release = fat_file_release, |
1da177e4 LT |
136 | .ioctl = fat_generic_ioctl, |
137 | .fsync = file_fsync, | |
5ffc4ef4 | 138 | .splice_read = generic_file_splice_read, |
1da177e4 LT |
139 | }; |
140 | ||
05eb0b51 OH |
141 | static int fat_cont_expand(struct inode *inode, loff_t size) |
142 | { | |
143 | struct address_space *mapping = inode->i_mapping; | |
144 | loff_t start = inode->i_size, count = size - inode->i_size; | |
145 | int err; | |
146 | ||
147 | err = generic_cont_expand_simple(inode, size); | |
148 | if (err) | |
149 | goto out; | |
150 | ||
151 | inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; | |
152 | mark_inode_dirty(inode); | |
153 | if (IS_SYNC(inode)) | |
154 | err = sync_page_range_nolock(inode, mapping, start, count); | |
155 | out: | |
156 | return err; | |
157 | } | |
158 | ||
1da177e4 LT |
159 | /* Free all clusters after the skip'th cluster. */ |
160 | static int fat_free(struct inode *inode, int skip) | |
161 | { | |
162 | struct super_block *sb = inode->i_sb; | |
163 | int err, wait, free_start, i_start, i_logstart; | |
164 | ||
165 | if (MSDOS_I(inode)->i_start == 0) | |
166 | return 0; | |
167 | ||
3b641407 OH |
168 | fat_cache_inval_inode(inode); |
169 | ||
1da177e4 | 170 | wait = IS_DIRSYNC(inode); |
3b641407 OH |
171 | i_start = free_start = MSDOS_I(inode)->i_start; |
172 | i_logstart = MSDOS_I(inode)->i_logstart; | |
173 | ||
174 | /* First, we write the new file size. */ | |
175 | if (!skip) { | |
176 | MSDOS_I(inode)->i_start = 0; | |
177 | MSDOS_I(inode)->i_logstart = 0; | |
178 | } | |
179 | MSDOS_I(inode)->i_attrs |= ATTR_ARCH; | |
180 | inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; | |
181 | if (wait) { | |
182 | err = fat_sync_inode(inode); | |
183 | if (err) { | |
184 | MSDOS_I(inode)->i_start = i_start; | |
185 | MSDOS_I(inode)->i_logstart = i_logstart; | |
186 | return err; | |
187 | } | |
188 | } else | |
189 | mark_inode_dirty(inode); | |
190 | ||
191 | /* Write a new EOF, and get the remaining cluster chain for freeing. */ | |
1da177e4 LT |
192 | if (skip) { |
193 | struct fat_entry fatent; | |
194 | int ret, fclus, dclus; | |
195 | ||
196 | ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus); | |
197 | if (ret < 0) | |
198 | return ret; | |
199 | else if (ret == FAT_ENT_EOF) | |
200 | return 0; | |
201 | ||
202 | fatent_init(&fatent); | |
203 | ret = fat_ent_read(inode, &fatent, dclus); | |
204 | if (ret == FAT_ENT_EOF) { | |
205 | fatent_brelse(&fatent); | |
206 | return 0; | |
207 | } else if (ret == FAT_ENT_FREE) { | |
208 | fat_fs_panic(sb, | |
209 | "%s: invalid cluster chain (i_pos %lld)", | |
8e24eea7 | 210 | __func__, MSDOS_I(inode)->i_pos); |
1da177e4 LT |
211 | ret = -EIO; |
212 | } else if (ret > 0) { | |
213 | err = fat_ent_write(inode, &fatent, FAT_ENT_EOF, wait); | |
214 | if (err) | |
215 | ret = err; | |
216 | } | |
217 | fatent_brelse(&fatent); | |
218 | if (ret < 0) | |
219 | return ret; | |
220 | ||
221 | free_start = ret; | |
1da177e4 | 222 | } |
1da177e4 LT |
223 | inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9); |
224 | ||
225 | /* Freeing the remained cluster chain */ | |
226 | return fat_free_clusters(inode, free_start); | |
1da177e4 LT |
227 | } |
228 | ||
229 | void fat_truncate(struct inode *inode) | |
230 | { | |
9c20616c | 231 | struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); |
1da177e4 LT |
232 | const unsigned int cluster_size = sbi->cluster_size; |
233 | int nr_clusters; | |
234 | ||
235 | /* | |
236 | * This protects against truncating a file bigger than it was then | |
237 | * trying to write into the hole. | |
238 | */ | |
239 | if (MSDOS_I(inode)->mmu_private > inode->i_size) | |
240 | MSDOS_I(inode)->mmu_private = inode->i_size; | |
241 | ||
242 | nr_clusters = (inode->i_size + (cluster_size - 1)) >> sbi->cluster_bits; | |
243 | ||
1da177e4 | 244 | fat_free(inode, nr_clusters); |
ae78bf9c | 245 | fat_flush_inodes(inode->i_sb, inode, NULL); |
1da177e4 LT |
246 | } |
247 | ||
da63fc7c OH |
248 | int fat_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) |
249 | { | |
250 | struct inode *inode = dentry->d_inode; | |
251 | generic_fillattr(inode, stat); | |
252 | stat->blksize = MSDOS_SB(inode->i_sb)->cluster_size; | |
253 | return 0; | |
254 | } | |
255 | EXPORT_SYMBOL_GPL(fat_getattr); | |
256 | ||
2d518f84 OH |
257 | static int fat_sanitize_mode(const struct msdos_sb_info *sbi, |
258 | struct inode *inode, umode_t *mode_ptr) | |
1278fdd3 | 259 | { |
2d518f84 | 260 | mode_t mask, perm; |
1278fdd3 | 261 | |
2d518f84 OH |
262 | /* |
263 | * Note, the basic check is already done by a caller of | |
264 | * (attr->ia_mode & ~MSDOS_VALID_MODE) | |
265 | */ | |
266 | ||
267 | if (S_ISREG(inode->i_mode)) | |
1278fdd3 OH |
268 | mask = sbi->options.fs_fmask; |
269 | else | |
270 | mask = sbi->options.fs_dmask; | |
271 | ||
2d518f84 OH |
272 | perm = *mode_ptr & ~(S_IFMT | mask); |
273 | ||
1278fdd3 OH |
274 | /* |
275 | * Of the r and x bits, all (subject to umask) must be present. Of the | |
276 | * w bits, either all (subject to umask) or none must be present. | |
277 | */ | |
2d518f84 | 278 | if ((perm & (S_IRUGO | S_IXUGO)) != (inode->i_mode & (S_IRUGO|S_IXUGO))) |
1278fdd3 | 279 | return -EPERM; |
2d518f84 | 280 | if ((perm & S_IWUGO) && ((perm & S_IWUGO) != (S_IWUGO & ~mask))) |
1278fdd3 OH |
281 | return -EPERM; |
282 | ||
2d518f84 OH |
283 | *mode_ptr &= S_IFMT | perm; |
284 | ||
1278fdd3 OH |
285 | return 0; |
286 | } | |
287 | ||
1ae43f82 OH |
288 | static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode) |
289 | { | |
290 | mode_t allow_utime = sbi->options.allow_utime; | |
291 | ||
292 | if (current->fsuid != inode->i_uid) { | |
293 | if (in_group_p(inode->i_gid)) | |
294 | allow_utime >>= 3; | |
295 | if (allow_utime & MAY_WRITE) | |
296 | return 1; | |
297 | } | |
298 | ||
299 | /* use a default check */ | |
300 | return 0; | |
301 | } | |
302 | ||
1278fdd3 OH |
303 | int fat_setattr(struct dentry *dentry, struct iattr *attr) |
304 | { | |
305 | struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb); | |
306 | struct inode *inode = dentry->d_inode; | |
2d518f84 | 307 | int error = 0; |
1ae43f82 | 308 | unsigned int ia_valid; |
1278fdd3 | 309 | |
1278fdd3 OH |
310 | /* |
311 | * Expand the file. Since inode_setattr() updates ->i_size | |
312 | * before calling the ->truncate(), but FAT needs to fill the | |
313 | * hole before it. | |
314 | */ | |
315 | if (attr->ia_valid & ATTR_SIZE) { | |
316 | if (attr->ia_size > inode->i_size) { | |
317 | error = fat_cont_expand(inode, attr->ia_size); | |
318 | if (error || attr->ia_valid == ATTR_SIZE) | |
319 | goto out; | |
320 | attr->ia_valid &= ~ATTR_SIZE; | |
321 | } | |
322 | } | |
323 | ||
1ae43f82 OH |
324 | /* Check for setting the inode time. */ |
325 | ia_valid = attr->ia_valid; | |
326 | if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET)) { | |
327 | if (fat_allow_set_time(sbi, inode)) | |
328 | attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET); | |
329 | } | |
330 | ||
1278fdd3 | 331 | error = inode_change_ok(inode, attr); |
1ae43f82 | 332 | attr->ia_valid = ia_valid; |
1278fdd3 OH |
333 | if (error) { |
334 | if (sbi->options.quiet) | |
335 | error = 0; | |
336 | goto out; | |
337 | } | |
2d518f84 | 338 | |
1278fdd3 OH |
339 | if (((attr->ia_valid & ATTR_UID) && |
340 | (attr->ia_uid != sbi->options.fs_uid)) || | |
341 | ((attr->ia_valid & ATTR_GID) && | |
e97e8de3 OH |
342 | (attr->ia_gid != sbi->options.fs_gid)) || |
343 | ((attr->ia_valid & ATTR_MODE) && | |
2d518f84 | 344 | (attr->ia_mode & ~MSDOS_VALID_MODE))) |
1278fdd3 OH |
345 | error = -EPERM; |
346 | ||
347 | if (error) { | |
348 | if (sbi->options.quiet) | |
349 | error = 0; | |
350 | goto out; | |
351 | } | |
352 | ||
2d518f84 OH |
353 | /* |
354 | * We don't return -EPERM here. Yes, strange, but this is too | |
355 | * old behavior. | |
356 | */ | |
357 | if (attr->ia_valid & ATTR_MODE) { | |
358 | if (fat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0) | |
359 | attr->ia_valid &= ~ATTR_MODE; | |
360 | } | |
1278fdd3 | 361 | |
2d518f84 | 362 | error = inode_setattr(inode, attr); |
1278fdd3 | 363 | out: |
1278fdd3 OH |
364 | return error; |
365 | } | |
366 | EXPORT_SYMBOL_GPL(fat_setattr); | |
367 | ||
754661f1 | 368 | const struct inode_operations fat_file_inode_operations = { |
1da177e4 | 369 | .truncate = fat_truncate, |
1278fdd3 | 370 | .setattr = fat_setattr, |
da63fc7c | 371 | .getattr = fat_getattr, |
1da177e4 | 372 | }; |