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CommitLineData
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
19int 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
107up:
108 mnt_drop_write(filp->f_path.mnt);
109up_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
118static 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 128const 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
141static 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);
155out:
156 return err;
157}
158
1da177e4
LT
159/* Free all clusters after the skip'th cluster. */
160static 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
229void 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
248int 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}
255EXPORT_SYMBOL_GPL(fat_getattr);
256
e97e8de3
OH
257static int fat_check_mode(const struct msdos_sb_info *sbi, struct inode *inode,
258 mode_t mode)
1278fdd3
OH
259{
260 mode_t mask, req = mode & ~S_IFMT;
261
262 if (S_ISREG(mode))
263 mask = sbi->options.fs_fmask;
264 else
265 mask = sbi->options.fs_dmask;
266
267 /*
268 * Of the r and x bits, all (subject to umask) must be present. Of the
269 * w bits, either all (subject to umask) or none must be present.
270 */
271 req &= ~mask;
e97e8de3 272 if ((req & (S_IRUGO | S_IXUGO)) != (inode->i_mode & (S_IRUGO|S_IXUGO)))
1278fdd3
OH
273 return -EPERM;
274 if ((req & S_IWUGO) && ((req & S_IWUGO) != (S_IWUGO & ~mask)))
275 return -EPERM;
276
277 return 0;
278}
279
1ae43f82
OH
280static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode)
281{
282 mode_t allow_utime = sbi->options.allow_utime;
283
284 if (current->fsuid != inode->i_uid) {
285 if (in_group_p(inode->i_gid))
286 allow_utime >>= 3;
287 if (allow_utime & MAY_WRITE)
288 return 1;
289 }
290
291 /* use a default check */
292 return 0;
293}
294
1278fdd3
OH
295int fat_setattr(struct dentry *dentry, struct iattr *attr)
296{
297 struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
298 struct inode *inode = dentry->d_inode;
299 int mask, error = 0;
1ae43f82 300 unsigned int ia_valid;
1278fdd3 301
1278fdd3
OH
302 /*
303 * Expand the file. Since inode_setattr() updates ->i_size
304 * before calling the ->truncate(), but FAT needs to fill the
305 * hole before it.
306 */
307 if (attr->ia_valid & ATTR_SIZE) {
308 if (attr->ia_size > inode->i_size) {
309 error = fat_cont_expand(inode, attr->ia_size);
310 if (error || attr->ia_valid == ATTR_SIZE)
311 goto out;
312 attr->ia_valid &= ~ATTR_SIZE;
313 }
314 }
315
1ae43f82
OH
316 /* Check for setting the inode time. */
317 ia_valid = attr->ia_valid;
318 if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET)) {
319 if (fat_allow_set_time(sbi, inode))
320 attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET);
321 }
322
1278fdd3 323 error = inode_change_ok(inode, attr);
1ae43f82 324 attr->ia_valid = ia_valid;
1278fdd3
OH
325 if (error) {
326 if (sbi->options.quiet)
327 error = 0;
328 goto out;
329 }
330 if (((attr->ia_valid & ATTR_UID) &&
331 (attr->ia_uid != sbi->options.fs_uid)) ||
332 ((attr->ia_valid & ATTR_GID) &&
e97e8de3
OH
333 (attr->ia_gid != sbi->options.fs_gid)) ||
334 ((attr->ia_valid & ATTR_MODE) &&
335 fat_check_mode(sbi, inode, attr->ia_mode) < 0))
1278fdd3
OH
336 error = -EPERM;
337
338 if (error) {
339 if (sbi->options.quiet)
340 error = 0;
341 goto out;
342 }
343
1278fdd3
OH
344 error = inode_setattr(inode, attr);
345 if (error)
346 goto out;
347
348 if (S_ISDIR(inode->i_mode))
349 mask = sbi->options.fs_dmask;
350 else
351 mask = sbi->options.fs_fmask;
352 inode->i_mode &= S_IFMT | (S_IRWXUGO & ~mask);
353out:
1278fdd3
OH
354 return error;
355}
356EXPORT_SYMBOL_GPL(fat_setattr);
357
754661f1 358const struct inode_operations fat_file_inode_operations = {
1da177e4 359 .truncate = fat_truncate,
1278fdd3 360 .setattr = fat_setattr,
da63fc7c 361 .getattr = fat_getattr,
1da177e4 362};