blob: a14c2f6a489e41bc2a6f23693da0ceac7da792ee [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>
Arnd Bergmann7845bc3e2010-05-17 08:13:47 +090011#include <linux/compat.h>
Dave Hansen42a74f22008-02-15 14:37:46 -080012#include <linux/mount.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/time.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>
OGAWA Hirofumi9e975da2008-11-06 12:53:46 -080020#include "fat.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070021
Christoph Hellwig21bea492009-06-08 21:38:31 +090022static int fat_ioctl_get_attributes(struct inode *inode, u32 __user *user_attr)
23{
24 u32 attr;
25
26 mutex_lock(&inode->i_mutex);
27 attr = fat_make_attrs(inode);
28 mutex_unlock(&inode->i_mutex);
29
30 return put_user(attr, user_attr);
31}
32
33static int fat_ioctl_set_attributes(struct file *file, u32 __user *user_attr)
34{
35 struct inode *inode = file->f_path.dentry->d_inode;
36 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
37 int is_dir = S_ISDIR(inode->i_mode);
38 u32 attr, oldattr;
39 struct iattr ia;
40 int err;
41
42 err = get_user(attr, user_attr);
43 if (err)
44 goto out;
45
46 mutex_lock(&inode->i_mutex);
47 err = mnt_want_write(file->f_path.mnt);
48 if (err)
49 goto out_unlock_inode;
50
51 /*
52 * ATTR_VOLUME and ATTR_DIR cannot be changed; this also
53 * prevents the user from turning us into a VFAT
54 * longname entry. Also, we obviously can't set
55 * any of the NTFS attributes in the high 24 bits.
56 */
57 attr &= 0xff & ~(ATTR_VOLUME | ATTR_DIR);
58 /* Merge in ATTR_VOLUME and ATTR_DIR */
59 attr |= (MSDOS_I(inode)->i_attrs & ATTR_VOLUME) |
60 (is_dir ? ATTR_DIR : 0);
61 oldattr = fat_make_attrs(inode);
62
63 /* Equivalent to a chmod() */
64 ia.ia_valid = ATTR_MODE | ATTR_CTIME;
65 ia.ia_ctime = current_fs_time(inode->i_sb);
66 if (is_dir)
67 ia.ia_mode = fat_make_mode(sbi, attr, S_IRWXUGO);
68 else {
69 ia.ia_mode = fat_make_mode(sbi, attr,
70 S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO));
71 }
72
73 /* The root directory has no attributes */
74 if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) {
75 err = -EINVAL;
76 goto out_drop_write;
77 }
78
79 if (sbi->options.sys_immutable &&
80 ((attr | oldattr) & ATTR_SYS) &&
81 !capable(CAP_LINUX_IMMUTABLE)) {
82 err = -EPERM;
83 goto out_drop_write;
84 }
85
86 /*
87 * The security check is questionable... We single
88 * out the RO attribute for checking by the security
89 * module, just because it maps to a file mode.
90 */
91 err = security_inode_setattr(file->f_path.dentry, &ia);
92 if (err)
93 goto out_drop_write;
94
95 /* This MUST be done before doing anything irreversible... */
96 err = fat_setattr(file->f_path.dentry, &ia);
97 if (err)
98 goto out_drop_write;
99
100 fsnotify_change(file->f_path.dentry, ia.ia_valid);
101 if (sbi->options.sys_immutable) {
102 if (attr & ATTR_SYS)
103 inode->i_flags |= S_IMMUTABLE;
104 else
105 inode->i_flags &= S_IMMUTABLE;
106 }
107
108 fat_save_attrs(inode, attr);
109 mark_inode_dirty(inode);
110out_drop_write:
111 mnt_drop_write(file->f_path.mnt);
112out_unlock_inode:
113 mutex_unlock(&inode->i_mutex);
114out:
115 return err;
116}
117
Arnd Bergmann7845bc3e2010-05-17 08:13:47 +0900118long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119{
Arnd Bergmann7845bc3e2010-05-17 08:13:47 +0900120 struct inode *inode = filp->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 u32 __user *user_attr = (u32 __user *)arg;
122
123 switch (cmd) {
124 case FAT_IOCTL_GET_ATTRIBUTES:
Christoph Hellwig21bea492009-06-08 21:38:31 +0900125 return fat_ioctl_get_attributes(inode, user_attr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 case FAT_IOCTL_SET_ATTRIBUTES:
Christoph Hellwig21bea492009-06-08 21:38:31 +0900127 return fat_ioctl_set_attributes(filp, user_attr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 default:
129 return -ENOTTY; /* Inappropriate ioctl for device */
130 }
131}
132
Arnd Bergmann7845bc3e2010-05-17 08:13:47 +0900133#ifdef CONFIG_COMPAT
134static long fat_generic_compat_ioctl(struct file *filp, unsigned int cmd,
135 unsigned long arg)
136
137{
138 return fat_generic_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
139}
140#endif
141
Chris Masonae78bf92006-09-29 02:00:03 -0700142static int fat_file_release(struct inode *inode, struct file *filp)
143{
144 if ((filp->f_mode & FMODE_WRITE) &&
145 MSDOS_SB(inode->i_sb)->options.flush) {
146 fat_flush_inodes(inode->i_sb, inode, NULL);
Jens Axboe8aa7e842009-07-09 14:52:32 +0200147 congestion_wait(BLK_RW_ASYNC, HZ/10);
Chris Masonae78bf92006-09-29 02:00:03 -0700148 }
149 return 0;
150}
151
Al Virob5224122009-06-07 13:44:36 -0400152int fat_file_fsync(struct file *filp, struct dentry *dentry, int datasync)
153{
154 struct inode *inode = dentry->d_inode;
155 int res, err;
156
157 res = simple_fsync(filp, dentry, datasync);
158 err = sync_mapping_buffers(MSDOS_SB(inode->i_sb)->fat_inode->i_mapping);
159
160 return res ? res : err;
161}
162
163
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800164const struct file_operations fat_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 .llseek = generic_file_llseek,
166 .read = do_sync_read,
167 .write = do_sync_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 .aio_read = generic_file_aio_read,
OGAWA Hirofumief402262005-09-16 19:28:13 -0700169 .aio_write = generic_file_aio_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 .mmap = generic_file_mmap,
Chris Masonae78bf92006-09-29 02:00:03 -0700171 .release = fat_file_release,
Arnd Bergmann7845bc3e2010-05-17 08:13:47 +0900172 .unlocked_ioctl = fat_generic_ioctl,
173#ifdef CONFIG_COMPAT
174 .compat_ioctl = fat_generic_compat_ioctl,
175#endif
Al Virob5224122009-06-07 13:44:36 -0400176 .fsync = fat_file_fsync,
Jens Axboe5ffc4ef2007-06-01 11:49:19 +0200177 .splice_read = generic_file_splice_read,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178};
179
OGAWA Hirofumi05eb0b52006-01-08 01:02:13 -0800180static int fat_cont_expand(struct inode *inode, loff_t size)
181{
182 struct address_space *mapping = inode->i_mapping;
183 loff_t start = inode->i_size, count = size - inode->i_size;
184 int err;
185
186 err = generic_cont_expand_simple(inode, size);
187 if (err)
188 goto out;
189
190 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
191 mark_inode_dirty(inode);
Jan Kara2f3d6752009-08-17 17:00:02 +0200192 if (IS_SYNC(inode)) {
193 int err2;
194
195 /*
196 * Opencode syncing since we don't have a file open to use
197 * standard fsync path.
198 */
199 err = filemap_fdatawrite_range(mapping, start,
200 start + count - 1);
201 err2 = sync_mapping_buffers(mapping);
202 if (!err)
203 err = err2;
204 err2 = write_inode_now(inode, 1);
205 if (!err)
206 err = err2;
207 if (!err) {
208 err = filemap_fdatawait_range(mapping, start,
209 start + count - 1);
210 }
211 }
OGAWA Hirofumi05eb0b52006-01-08 01:02:13 -0800212out:
213 return err;
214}
215
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216/* Free all clusters after the skip'th cluster. */
217static int fat_free(struct inode *inode, int skip)
218{
219 struct super_block *sb = inode->i_sb;
220 int err, wait, free_start, i_start, i_logstart;
221
222 if (MSDOS_I(inode)->i_start == 0)
223 return 0;
224
OGAWA Hirofumi3b641402006-02-03 03:04:44 -0800225 fat_cache_inval_inode(inode);
226
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 wait = IS_DIRSYNC(inode);
OGAWA Hirofumi3b641402006-02-03 03:04:44 -0800228 i_start = free_start = MSDOS_I(inode)->i_start;
229 i_logstart = MSDOS_I(inode)->i_logstart;
230
231 /* First, we write the new file size. */
232 if (!skip) {
233 MSDOS_I(inode)->i_start = 0;
234 MSDOS_I(inode)->i_logstart = 0;
235 }
236 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
237 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
238 if (wait) {
239 err = fat_sync_inode(inode);
240 if (err) {
241 MSDOS_I(inode)->i_start = i_start;
242 MSDOS_I(inode)->i_logstart = i_logstart;
243 return err;
244 }
245 } else
246 mark_inode_dirty(inode);
247
248 /* Write a new EOF, and get the remaining cluster chain for freeing. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 if (skip) {
250 struct fat_entry fatent;
251 int ret, fclus, dclus;
252
253 ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus);
254 if (ret < 0)
255 return ret;
256 else if (ret == FAT_ENT_EOF)
257 return 0;
258
259 fatent_init(&fatent);
260 ret = fat_ent_read(inode, &fatent, dclus);
261 if (ret == FAT_ENT_EOF) {
262 fatent_brelse(&fatent);
263 return 0;
264 } else if (ret == FAT_ENT_FREE) {
Denis Karpov85c78592009-06-04 02:34:22 +0900265 fat_fs_error(sb,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 "%s: invalid cluster chain (i_pos %lld)",
Harvey Harrison8e24eea2008-04-30 00:55:09 -0700267 __func__, MSDOS_I(inode)->i_pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 ret = -EIO;
269 } else if (ret > 0) {
270 err = fat_ent_write(inode, &fatent, FAT_ENT_EOF, wait);
271 if (err)
272 ret = err;
273 }
274 fatent_brelse(&fatent);
275 if (ret < 0)
276 return ret;
277
278 free_start = ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9);
281
282 /* Freeing the remained cluster chain */
283 return fat_free_clusters(inode, free_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284}
285
286void fat_truncate(struct inode *inode)
287{
Jonathan Corbet9c206162008-05-29 17:14:05 -0600288 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 const unsigned int cluster_size = sbi->cluster_size;
290 int nr_clusters;
291
292 /*
293 * This protects against truncating a file bigger than it was then
294 * trying to write into the hole.
295 */
296 if (MSDOS_I(inode)->mmu_private > inode->i_size)
297 MSDOS_I(inode)->mmu_private = inode->i_size;
298
299 nr_clusters = (inode->i_size + (cluster_size - 1)) >> sbi->cluster_bits;
300
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 fat_free(inode, nr_clusters);
Chris Masonae78bf92006-09-29 02:00:03 -0700302 fat_flush_inodes(inode->i_sb, inode, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303}
304
OGAWA Hirofumida63fc72006-11-16 01:19:28 -0800305int fat_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
306{
307 struct inode *inode = dentry->d_inode;
308 generic_fillattr(inode, stat);
309 stat->blksize = MSDOS_SB(inode->i_sb)->cluster_size;
310 return 0;
311}
312EXPORT_SYMBOL_GPL(fat_getattr);
313
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700314static int fat_sanitize_mode(const struct msdos_sb_info *sbi,
315 struct inode *inode, umode_t *mode_ptr)
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700316{
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700317 mode_t mask, perm;
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700318
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700319 /*
320 * Note, the basic check is already done by a caller of
OGAWA Hirofumi9c0aa1b2008-11-06 12:53:54 -0800321 * (attr->ia_mode & ~FAT_VALID_MODE)
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700322 */
323
324 if (S_ISREG(inode->i_mode))
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700325 mask = sbi->options.fs_fmask;
326 else
327 mask = sbi->options.fs_dmask;
328
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700329 perm = *mode_ptr & ~(S_IFMT | mask);
330
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700331 /*
332 * Of the r and x bits, all (subject to umask) must be present. Of the
333 * w bits, either all (subject to umask) or none must be present.
OGAWA Hirofumidfc209c2008-11-06 12:53:55 -0800334 *
335 * If fat_mode_can_hold_ro(inode) is false, can't change w bits.
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700336 */
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700337 if ((perm & (S_IRUGO | S_IXUGO)) != (inode->i_mode & (S_IRUGO|S_IXUGO)))
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700338 return -EPERM;
OGAWA Hirofumidfc209c2008-11-06 12:53:55 -0800339 if (fat_mode_can_hold_ro(inode)) {
340 if ((perm & S_IWUGO) && ((perm & S_IWUGO) != (S_IWUGO & ~mask)))
341 return -EPERM;
342 } else {
343 if ((perm & S_IWUGO) != (S_IWUGO & ~mask))
344 return -EPERM;
345 }
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700346
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700347 *mode_ptr &= S_IFMT | perm;
348
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700349 return 0;
350}
351
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700352static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode)
353{
354 mode_t allow_utime = sbi->options.allow_utime;
355
David Howellsf0ce7ee2008-11-14 10:38:52 +1100356 if (current_fsuid() != inode->i_uid) {
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700357 if (in_group_p(inode->i_gid))
358 allow_utime >>= 3;
359 if (allow_utime & MAY_WRITE)
360 return 1;
361 }
362
363 /* use a default check */
364 return 0;
365}
366
OGAWA Hirofumi17263842008-08-02 13:59:37 +0900367#define TIMES_SET_FLAGS (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)
OGAWA Hirofumi9c0aa1b2008-11-06 12:53:54 -0800368/* valid file mode bits */
369#define FAT_VALID_MODE (S_IFREG | S_IFDIR | S_IRWXUGO)
OGAWA Hirofumi17263842008-08-02 13:59:37 +0900370
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700371int fat_setattr(struct dentry *dentry, struct iattr *attr)
372{
373 struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
374 struct inode *inode = dentry->d_inode;
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700375 unsigned int ia_valid;
OGAWA Hirofumidfc209c2008-11-06 12:53:55 -0800376 int error;
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700377
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700378 /*
379 * Expand the file. Since inode_setattr() updates ->i_size
380 * before calling the ->truncate(), but FAT needs to fill the
381 * hole before it.
382 */
383 if (attr->ia_valid & ATTR_SIZE) {
384 if (attr->ia_size > inode->i_size) {
385 error = fat_cont_expand(inode, attr->ia_size);
386 if (error || attr->ia_valid == ATTR_SIZE)
387 goto out;
388 attr->ia_valid &= ~ATTR_SIZE;
389 }
390 }
391
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700392 /* Check for setting the inode time. */
393 ia_valid = attr->ia_valid;
OGAWA Hirofumi17263842008-08-02 13:59:37 +0900394 if (ia_valid & TIMES_SET_FLAGS) {
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700395 if (fat_allow_set_time(sbi, inode))
OGAWA Hirofumi17263842008-08-02 13:59:37 +0900396 attr->ia_valid &= ~TIMES_SET_FLAGS;
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700397 }
398
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700399 error = inode_change_ok(inode, attr);
OGAWA Hirofumi1ae43f82008-04-28 02:16:26 -0700400 attr->ia_valid = ia_valid;
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700401 if (error) {
402 if (sbi->options.quiet)
403 error = 0;
404 goto out;
405 }
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700406
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700407 if (((attr->ia_valid & ATTR_UID) &&
408 (attr->ia_uid != sbi->options.fs_uid)) ||
409 ((attr->ia_valid & ATTR_GID) &&
OGAWA Hirofumie97e8de2008-04-28 02:16:26 -0700410 (attr->ia_gid != sbi->options.fs_gid)) ||
411 ((attr->ia_valid & ATTR_MODE) &&
OGAWA Hirofumi9c0aa1b2008-11-06 12:53:54 -0800412 (attr->ia_mode & ~FAT_VALID_MODE)))
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700413 error = -EPERM;
414
415 if (error) {
416 if (sbi->options.quiet)
417 error = 0;
418 goto out;
419 }
420
OGAWA Hirofumi2d518f82008-06-12 15:21:28 -0700421 /*
422 * We don't return -EPERM here. Yes, strange, but this is too
423 * old behavior.
424 */
425 if (attr->ia_valid & ATTR_MODE) {
426 if (fat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
427 attr->ia_valid &= ~ATTR_MODE;
428 }
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700429
OGAWA Hirofumidfc209c2008-11-06 12:53:55 -0800430 if (attr->ia_valid)
431 error = inode_setattr(inode, attr);
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700432out:
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700433 return error;
434}
435EXPORT_SYMBOL_GPL(fat_setattr);
436
Arjan van de Ven754661f2007-02-12 00:55:38 -0800437const struct inode_operations fat_file_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438 .truncate = fat_truncate,
OGAWA Hirofumi1278fdd2008-04-28 02:16:25 -0700439 .setattr = fat_setattr,
OGAWA Hirofumida63fc72006-11-16 01:19:28 -0800440 .getattr = fat_getattr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441};