blob: 6214287210f5fe27cb13e97f8e26d1fcdf78645b [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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/buffer_head.h>
OGAWA Hirofumi05eb0b52006-01-08 01:02:13 -080014#include <linux/writeback.h>
Andrew Morton3fcfab12006-10-19 23:28:16 -070015#include <linux/backing-dev.h>
Chris Masonae78bf92006-09-29 02:00:03 -070016#include <linux/blkdev.h>
Miklos Szeredib1da47e2008-07-01 15:01:28 +020017#include <linux/fsnotify.h>
18#include <linux/security.h>
OGAWA Hirofumi9e975da2008-11-06 12:53:46 -080019#include "fat.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
OGAWA Hirofumi91834822008-11-06 12:53:54 -080032 mutex_lock(&inode->i_mutex);
33 attr = fat_make_attrs(inode);
34 mutex_unlock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
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
Jes Sorensen1b1dcc12006-01-09 15:59:24 -080048 mutex_lock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070049
Dave Hansen42a74f22008-02-15 14:37:46 -080050 err = mnt_want_write(filp->f_path.mnt);
51 if (err)
52 goto up_no_drop_write;
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
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);
OGAWA Hirofumi9c0aa1b2008-11-06 12:53:54 -080064 oldattr = fat_make_attrs(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
66 /* Equivalent to a chmod() */
67 ia.ia_valid = ATTR_MODE | ATTR_CTIME;
Miklos Szeredib1da47e2008-07-01 15:01:28 +020068 ia.ia_ctime = current_fs_time(inode->i_sb);
OGAWA Hirofumi9c0aa1b2008-11-06 12:53:54 -080069 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));
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 }
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
Miklos Szeredib1da47e2008-07-01 15:01:28 +020091 /*
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);
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 if (err)
98 goto up;
99
Miklos Szeredib1da47e2008-07-01 15:01:28 +0200100 /* This MUST be done before doing anything irreversible... */
101 err = fat_setattr(filp->f_path.dentry, &ia);
102 if (err)
103 goto up;
104
105 fsnotify_change(filp->f_path.dentry, ia.ia_valid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 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
OGAWA Hirofumi9c0aa1b2008-11-06 12:53:54 -0800113 fat_save_attrs(inode, attr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 mark_inode_dirty(inode);
Dave Hansen42a74f22008-02-15 14:37:46 -0800115up:
116 mnt_drop_write(filp->f_path.mnt);
117up_no_drop_write:
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800118 mutex_unlock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 return err;
120 }
121 default:
122 return -ENOTTY; /* Inappropriate ioctl for device */
123 }
124}
125
Chris Masonae78bf92006-09-29 02:00:03 -0700126static 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);
Andrew Morton3fcfab12006-10-19 23:28:16 -0700131 congestion_wait(WRITE, HZ/10);
Chris Masonae78bf92006-09-29 02:00:03 -0700132 }
133 return 0;
134}
135
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800136const struct file_operations fat_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137 .llseek = generic_file_llseek,
138 .read = do_sync_read,
139 .write = do_sync_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 .aio_read = generic_file_aio_read,
OGAWA Hirofumief402262005-09-16 19:28:13 -0700141 .aio_write = generic_file_aio_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 .mmap = generic_file_mmap,
Chris Masonae78bf92006-09-29 02:00:03 -0700143 .release = fat_file_release,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 .ioctl = fat_generic_ioctl,
145 .fsync = file_fsync,
Jens Axboe5ffc4ef2007-06-01 11:49:19 +0200146 .splice_read = generic_file_splice_read,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147};
148
OGAWA Hirofumi05eb0b52006-01-08 01:02:13 -0800149static 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);
163out:
164 return err;
165}
166
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167/* Free all clusters after the skip'th cluster. */
168static 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
OGAWA Hirofumi3b641402006-02-03 03:04:44 -0800176 fat_cache_inval_inode(inode);
177
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 wait = IS_DIRSYNC(inode);
OGAWA Hirofumi3b641402006-02-03 03:04:44 -0800179 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. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 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) {
Denis Karpov85c78592009-06-04 02:34:22 +0900216 fat_fs_error(sb,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 "%s: invalid cluster chain (i_pos %lld)",
Harvey Harrison8e24eea2008-04-30 00:55:09 -0700218 __func__, MSDOS_I(inode)->i_pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 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);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235}
236
237void fat_truncate(struct inode *inode)
238{
Jonathan Corbet9c206162008-05-29 17:14:05 -0600239 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 fat_free(inode, nr_clusters);
Chris Masonae78bf92006-09-29 02:00:03 -0700253 fat_flush_inodes(inode->i_sb, inode, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254}
255
OGAWA Hirofumida63fc72006-11-16 01:19:28 -0800256int 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}
263EXPORT_SYMBOL_GPL(fat_getattr);
264
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700265static int fat_sanitize_mode(const struct msdos_sb_info *sbi,
266 struct inode *inode, umode_t *mode_ptr)
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700267{
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700268 mode_t mask, perm;
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700269
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700270 /*
271 * Note, the basic check is already done by a caller of
OGAWA Hirofumi9c0aa1b2008-11-06 12:53:54 -0800272 * (attr->ia_mode & ~FAT_VALID_MODE)
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700273 */
274
275 if (S_ISREG(inode->i_mode))
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700276 mask = sbi->options.fs_fmask;
277 else
278 mask = sbi->options.fs_dmask;
279
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700280 perm = *mode_ptr & ~(S_IFMT | mask);
281
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700282 /*
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.
OGAWA Hirofumidfc209c2008-11-06 12:53:55 -0800285 *
286 * If fat_mode_can_hold_ro(inode) is false, can't change w bits.
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700287 */
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700288 if ((perm & (S_IRUGO | S_IXUGO)) != (inode->i_mode & (S_IRUGO|S_IXUGO)))
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700289 return -EPERM;
OGAWA Hirofumidfc209c2008-11-06 12:53:55 -0800290 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 }
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700297
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700298 *mode_ptr &= S_IFMT | perm;
299
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700300 return 0;
301}
302
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700303static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode)
304{
305 mode_t allow_utime = sbi->options.allow_utime;
306
David Howellsf0ce7ee2008-11-14 10:38:52 +1100307 if (current_fsuid() != inode->i_uid) {
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700308 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
OGAWA Hirofumi17263842008-08-02 13:59:37 +0900318#define TIMES_SET_FLAGS (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)
OGAWA Hirofumi9c0aa1b2008-11-06 12:53:54 -0800319/* valid file mode bits */
320#define FAT_VALID_MODE (S_IFREG | S_IFDIR | S_IRWXUGO)
OGAWA Hirofumi17263842008-08-02 13:59:37 +0900321
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700322int 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;
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700326 unsigned int ia_valid;
OGAWA Hirofumidfc209c2008-11-06 12:53:55 -0800327 int error;
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700328
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700329 /*
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
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700343 /* Check for setting the inode time. */
344 ia_valid = attr->ia_valid;
OGAWA Hirofumi17263842008-08-02 13:59:37 +0900345 if (ia_valid & TIMES_SET_FLAGS) {
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700346 if (fat_allow_set_time(sbi, inode))
OGAWA Hirofumi17263842008-08-02 13:59:37 +0900347 attr->ia_valid &= ~TIMES_SET_FLAGS;
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700348 }
349
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700350 error = inode_change_ok(inode, attr);
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700351 attr->ia_valid = ia_valid;
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700352 if (error) {
353 if (sbi->options.quiet)
354 error = 0;
355 goto out;
356 }
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700357
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700358 if (((attr->ia_valid & ATTR_UID) &&
359 (attr->ia_uid != sbi->options.fs_uid)) ||
360 ((attr->ia_valid & ATTR_GID) &&
OGAWA Hirofumie97e8de2008-04-28 02:16:26 -0700361 (attr->ia_gid != sbi->options.fs_gid)) ||
362 ((attr->ia_valid & ATTR_MODE) &&
OGAWA Hirofumi9c0aa1b2008-11-06 12:53:54 -0800363 (attr->ia_mode & ~FAT_VALID_MODE)))
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700364 error = -EPERM;
365
366 if (error) {
367 if (sbi->options.quiet)
368 error = 0;
369 goto out;
370 }
371
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700372 /*
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 }
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700380
OGAWA Hirofumidfc209c2008-11-06 12:53:55 -0800381 if (attr->ia_valid)
382 error = inode_setattr(inode, attr);
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700383out:
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700384 return error;
385}
386EXPORT_SYMBOL_GPL(fat_setattr);
387
Arjan van de Ven754661f2007-02-12 00:55:38 -0800388const struct inode_operations fat_file_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 .truncate = fat_truncate,
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700390 .setattr = fat_setattr,
OGAWA Hirofumida63fc72006-11-16 01:19:28 -0800391 .getattr = fat_getattr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392};