blob: ddde37025ca674827d5dafe836a0956c70648f06 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Randy Dunlap16f7e0f2006-01-11 12:17:46 -08009#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010#include <linux/module.h>
Dave Hansen42a74f22008-02-15 14:37:46 -080011#include <linux/mount.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/time.h>
13#include <linux/msdos_fs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/buffer_head.h>
OGAWA Hirofumi05eb0b52006-01-08 01:02:13 -080015#include <linux/writeback.h>
Andrew Morton3fcfab12006-10-19 23:28:16 -070016#include <linux/backing-dev.h>
Chris Masonae78bf92006-09-29 02:00:03 -070017#include <linux/blkdev.h>
Miklos Szeredib1da47e2008-07-01 15:01:28 +020018#include <linux/fsnotify.h>
19#include <linux/security.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020
Linus Torvalds1da177e2005-04-16 15:20:36 -070021int 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 {
30 u32 attr;
31
32 if (inode->i_ino == MSDOS_ROOT_INO)
33 attr = ATTR_DIR;
34 else
35 attr = fat_attr(inode);
36
37 return put_user(attr, user_attr);
38 }
39 case FAT_IOCTL_SET_ATTRIBUTES:
40 {
41 u32 attr, oldattr;
42 int err, is_dir = S_ISDIR(inode->i_mode);
43 struct iattr ia;
44
45 err = get_user(attr, user_attr);
46 if (err)
47 return err;
48
Jes Sorensen1b1dcc12006-01-09 15:59:24 -080049 mutex_lock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070050
Dave Hansen42a74f22008-02-15 14:37:46 -080051 err = mnt_want_write(filp->f_path.mnt);
52 if (err)
53 goto up_no_drop_write;
Linus Torvalds1da177e2005-04-16 15:20:36 -070054
55 /*
56 * ATTR_VOLUME and ATTR_DIR cannot be changed; this also
57 * prevents the user from turning us into a VFAT
58 * longname entry. Also, we obviously can't set
59 * any of the NTFS attributes in the high 24 bits.
60 */
61 attr &= 0xff & ~(ATTR_VOLUME | ATTR_DIR);
62 /* Merge in ATTR_VOLUME and ATTR_DIR */
63 attr |= (MSDOS_I(inode)->i_attrs & ATTR_VOLUME) |
64 (is_dir ? ATTR_DIR : 0);
65 oldattr = fat_attr(inode);
66
67 /* Equivalent to a chmod() */
68 ia.ia_valid = ATTR_MODE | ATTR_CTIME;
Miklos Szeredib1da47e2008-07-01 15:01:28 +020069 ia.ia_ctime = current_fs_time(inode->i_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 if (is_dir) {
71 ia.ia_mode = MSDOS_MKMODE(attr,
72 S_IRWXUGO & ~sbi->options.fs_dmask)
73 | S_IFDIR;
74 } else {
75 ia.ia_mode = MSDOS_MKMODE(attr,
76 (S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO))
77 & ~sbi->options.fs_fmask)
78 | S_IFREG;
79 }
80
81 /* The root directory has no attributes */
82 if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) {
83 err = -EINVAL;
84 goto up;
85 }
86
87 if (sbi->options.sys_immutable) {
88 if ((attr | oldattr) & ATTR_SYS) {
89 if (!capable(CAP_LINUX_IMMUTABLE)) {
90 err = -EPERM;
91 goto up;
92 }
93 }
94 }
95
Miklos Szeredib1da47e2008-07-01 15:01:28 +020096 /*
97 * The security check is questionable... We single
98 * out the RO attribute for checking by the security
99 * module, just because it maps to a file mode.
100 */
101 err = security_inode_setattr(filp->f_path.dentry, &ia);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 if (err)
103 goto up;
104
Miklos Szeredib1da47e2008-07-01 15:01:28 +0200105 /* This MUST be done before doing anything irreversible... */
106 err = fat_setattr(filp->f_path.dentry, &ia);
107 if (err)
108 goto up;
109
110 fsnotify_change(filp->f_path.dentry, ia.ia_valid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 if (sbi->options.sys_immutable) {
112 if (attr & ATTR_SYS)
113 inode->i_flags |= S_IMMUTABLE;
114 else
115 inode->i_flags &= S_IMMUTABLE;
116 }
117
118 MSDOS_I(inode)->i_attrs = attr & ATTR_UNUSED;
119 mark_inode_dirty(inode);
Dave Hansen42a74f22008-02-15 14:37:46 -0800120up:
121 mnt_drop_write(filp->f_path.mnt);
122up_no_drop_write:
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800123 mutex_unlock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 return err;
125 }
126 default:
127 return -ENOTTY; /* Inappropriate ioctl for device */
128 }
129}
130
Chris Masonae78bf92006-09-29 02:00:03 -0700131static int fat_file_release(struct inode *inode, struct file *filp)
132{
133 if ((filp->f_mode & FMODE_WRITE) &&
134 MSDOS_SB(inode->i_sb)->options.flush) {
135 fat_flush_inodes(inode->i_sb, inode, NULL);
Andrew Morton3fcfab12006-10-19 23:28:16 -0700136 congestion_wait(WRITE, HZ/10);
Chris Masonae78bf92006-09-29 02:00:03 -0700137 }
138 return 0;
139}
140
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800141const struct file_operations fat_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 .llseek = generic_file_llseek,
143 .read = do_sync_read,
144 .write = do_sync_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 .aio_read = generic_file_aio_read,
OGAWA Hirofumief402262005-09-16 19:28:13 -0700146 .aio_write = generic_file_aio_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 .mmap = generic_file_mmap,
Chris Masonae78bf92006-09-29 02:00:03 -0700148 .release = fat_file_release,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 .ioctl = fat_generic_ioctl,
150 .fsync = file_fsync,
Jens Axboe5ffc4ef2007-06-01 11:49:19 +0200151 .splice_read = generic_file_splice_read,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152};
153
OGAWA Hirofumi05eb0b52006-01-08 01:02:13 -0800154static int fat_cont_expand(struct inode *inode, loff_t size)
155{
156 struct address_space *mapping = inode->i_mapping;
157 loff_t start = inode->i_size, count = size - inode->i_size;
158 int err;
159
160 err = generic_cont_expand_simple(inode, size);
161 if (err)
162 goto out;
163
164 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
165 mark_inode_dirty(inode);
166 if (IS_SYNC(inode))
167 err = sync_page_range_nolock(inode, mapping, start, count);
168out:
169 return err;
170}
171
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172/* Free all clusters after the skip'th cluster. */
173static int fat_free(struct inode *inode, int skip)
174{
175 struct super_block *sb = inode->i_sb;
176 int err, wait, free_start, i_start, i_logstart;
177
178 if (MSDOS_I(inode)->i_start == 0)
179 return 0;
180
OGAWA Hirofumi3b641402006-02-03 03:04:44 -0800181 fat_cache_inval_inode(inode);
182
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 wait = IS_DIRSYNC(inode);
OGAWA Hirofumi3b641402006-02-03 03:04:44 -0800184 i_start = free_start = MSDOS_I(inode)->i_start;
185 i_logstart = MSDOS_I(inode)->i_logstart;
186
187 /* First, we write the new file size. */
188 if (!skip) {
189 MSDOS_I(inode)->i_start = 0;
190 MSDOS_I(inode)->i_logstart = 0;
191 }
192 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
193 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
194 if (wait) {
195 err = fat_sync_inode(inode);
196 if (err) {
197 MSDOS_I(inode)->i_start = i_start;
198 MSDOS_I(inode)->i_logstart = i_logstart;
199 return err;
200 }
201 } else
202 mark_inode_dirty(inode);
203
204 /* Write a new EOF, and get the remaining cluster chain for freeing. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 if (skip) {
206 struct fat_entry fatent;
207 int ret, fclus, dclus;
208
209 ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus);
210 if (ret < 0)
211 return ret;
212 else if (ret == FAT_ENT_EOF)
213 return 0;
214
215 fatent_init(&fatent);
216 ret = fat_ent_read(inode, &fatent, dclus);
217 if (ret == FAT_ENT_EOF) {
218 fatent_brelse(&fatent);
219 return 0;
220 } else if (ret == FAT_ENT_FREE) {
221 fat_fs_panic(sb,
222 "%s: invalid cluster chain (i_pos %lld)",
Harvey Harrison8e24eea2008-04-30 00:55:09 -0700223 __func__, MSDOS_I(inode)->i_pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 ret = -EIO;
225 } else if (ret > 0) {
226 err = fat_ent_write(inode, &fatent, FAT_ENT_EOF, wait);
227 if (err)
228 ret = err;
229 }
230 fatent_brelse(&fatent);
231 if (ret < 0)
232 return ret;
233
234 free_start = ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9);
237
238 /* Freeing the remained cluster chain */
239 return fat_free_clusters(inode, free_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240}
241
242void fat_truncate(struct inode *inode)
243{
Jonathan Corbet9c206162008-05-29 17:14:05 -0600244 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 const unsigned int cluster_size = sbi->cluster_size;
246 int nr_clusters;
247
248 /*
249 * This protects against truncating a file bigger than it was then
250 * trying to write into the hole.
251 */
252 if (MSDOS_I(inode)->mmu_private > inode->i_size)
253 MSDOS_I(inode)->mmu_private = inode->i_size;
254
255 nr_clusters = (inode->i_size + (cluster_size - 1)) >> sbi->cluster_bits;
256
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 fat_free(inode, nr_clusters);
Chris Masonae78bf92006-09-29 02:00:03 -0700258 fat_flush_inodes(inode->i_sb, inode, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259}
260
OGAWA Hirofumida63fc72006-11-16 01:19:28 -0800261int fat_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
262{
263 struct inode *inode = dentry->d_inode;
264 generic_fillattr(inode, stat);
265 stat->blksize = MSDOS_SB(inode->i_sb)->cluster_size;
266 return 0;
267}
268EXPORT_SYMBOL_GPL(fat_getattr);
269
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700270static int fat_sanitize_mode(const struct msdos_sb_info *sbi,
271 struct inode *inode, umode_t *mode_ptr)
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700272{
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700273 mode_t mask, perm;
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700274
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700275 /*
276 * Note, the basic check is already done by a caller of
277 * (attr->ia_mode & ~MSDOS_VALID_MODE)
278 */
279
280 if (S_ISREG(inode->i_mode))
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700281 mask = sbi->options.fs_fmask;
282 else
283 mask = sbi->options.fs_dmask;
284
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700285 perm = *mode_ptr & ~(S_IFMT | mask);
286
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700287 /*
288 * Of the r and x bits, all (subject to umask) must be present. Of the
289 * w bits, either all (subject to umask) or none must be present.
290 */
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700291 if ((perm & (S_IRUGO | S_IXUGO)) != (inode->i_mode & (S_IRUGO|S_IXUGO)))
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700292 return -EPERM;
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700293 if ((perm & S_IWUGO) && ((perm & S_IWUGO) != (S_IWUGO & ~mask)))
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700294 return -EPERM;
295
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700296 *mode_ptr &= S_IFMT | perm;
297
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700298 return 0;
299}
300
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700301static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode)
302{
303 mode_t allow_utime = sbi->options.allow_utime;
304
305 if (current->fsuid != inode->i_uid) {
306 if (in_group_p(inode->i_gid))
307 allow_utime >>= 3;
308 if (allow_utime & MAY_WRITE)
309 return 1;
310 }
311
312 /* use a default check */
313 return 0;
314}
315
OGAWA Hirofumi17263842008-08-02 13:59:37 +0900316#define TIMES_SET_FLAGS (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)
317
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700318int fat_setattr(struct dentry *dentry, struct iattr *attr)
319{
320 struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
321 struct inode *inode = dentry->d_inode;
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700322 int error = 0;
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700323 unsigned int ia_valid;
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700324
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700325 /*
326 * Expand the file. Since inode_setattr() updates ->i_size
327 * before calling the ->truncate(), but FAT needs to fill the
328 * hole before it.
329 */
330 if (attr->ia_valid & ATTR_SIZE) {
331 if (attr->ia_size > inode->i_size) {
332 error = fat_cont_expand(inode, attr->ia_size);
333 if (error || attr->ia_valid == ATTR_SIZE)
334 goto out;
335 attr->ia_valid &= ~ATTR_SIZE;
336 }
337 }
338
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700339 /* Check for setting the inode time. */
340 ia_valid = attr->ia_valid;
OGAWA Hirofumi17263842008-08-02 13:59:37 +0900341 if (ia_valid & TIMES_SET_FLAGS) {
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700342 if (fat_allow_set_time(sbi, inode))
OGAWA Hirofumi17263842008-08-02 13:59:37 +0900343 attr->ia_valid &= ~TIMES_SET_FLAGS;
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700344 }
345
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700346 error = inode_change_ok(inode, attr);
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700347 attr->ia_valid = ia_valid;
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700348 if (error) {
349 if (sbi->options.quiet)
350 error = 0;
351 goto out;
352 }
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700353
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700354 if (((attr->ia_valid & ATTR_UID) &&
355 (attr->ia_uid != sbi->options.fs_uid)) ||
356 ((attr->ia_valid & ATTR_GID) &&
OGAWA Hirofumie97e8de2008-04-28 02:16:26 -0700357 (attr->ia_gid != sbi->options.fs_gid)) ||
358 ((attr->ia_valid & ATTR_MODE) &&
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700359 (attr->ia_mode & ~MSDOS_VALID_MODE)))
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700360 error = -EPERM;
361
362 if (error) {
363 if (sbi->options.quiet)
364 error = 0;
365 goto out;
366 }
367
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700368 /*
369 * We don't return -EPERM here. Yes, strange, but this is too
370 * old behavior.
371 */
372 if (attr->ia_valid & ATTR_MODE) {
373 if (fat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
374 attr->ia_valid &= ~ATTR_MODE;
375 }
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700376
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700377 error = inode_setattr(inode, attr);
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700378out:
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700379 return error;
380}
381EXPORT_SYMBOL_GPL(fat_setattr);
382
Arjan van de Ven754661f2007-02-12 00:55:38 -0800383const struct inode_operations fat_file_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 .truncate = fat_truncate,
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700385 .setattr = fat_setattr,
OGAWA Hirofumida63fc72006-11-16 01:19:28 -0800386 .getattr = fat_getattr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387};