blob: 69a83b59dce80bdc84f1d4507e1ad74195c38690 [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>
11#include <linux/time.h>
12#include <linux/msdos_fs.h>
13#include <linux/smp_lock.h>
14#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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018
Linus Torvalds1da177e2005-04-16 15:20:36 -070019int 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
Jes Sorensen1b1dcc12006-01-09 15:59:24 -080047 mutex_lock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070048
49 if (IS_RDONLY(inode)) {
50 err = -EROFS;
51 goto up;
52 }
53
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);
64 oldattr = fat_attr(inode);
65
66 /* Equivalent to a chmod() */
67 ia.ia_valid = ATTR_MODE | ATTR_CTIME;
68 if (is_dir) {
69 ia.ia_mode = MSDOS_MKMODE(attr,
70 S_IRWXUGO & ~sbi->options.fs_dmask)
71 | S_IFDIR;
72 } else {
73 ia.ia_mode = MSDOS_MKMODE(attr,
74 (S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO))
75 & ~sbi->options.fs_fmask)
76 | S_IFREG;
77 }
78
79 /* The root directory has no attributes */
80 if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) {
81 err = -EINVAL;
82 goto up;
83 }
84
85 if (sbi->options.sys_immutable) {
86 if ((attr | oldattr) & ATTR_SYS) {
87 if (!capable(CAP_LINUX_IMMUTABLE)) {
88 err = -EPERM;
89 goto up;
90 }
91 }
92 }
93
94 /* This MUST be done before doing anything irreversible... */
Josef "Jeff" Sipekdba32302006-12-08 02:36:39 -080095 err = notify_change(filp->f_path.dentry, &ia);
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 if (err)
97 goto up;
98
99 if (sbi->options.sys_immutable) {
100 if (attr & ATTR_SYS)
101 inode->i_flags |= S_IMMUTABLE;
102 else
103 inode->i_flags &= S_IMMUTABLE;
104 }
105
106 MSDOS_I(inode)->i_attrs = attr & ATTR_UNUSED;
107 mark_inode_dirty(inode);
108 up:
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800109 mutex_unlock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 return err;
111 }
112 default:
113 return -ENOTTY; /* Inappropriate ioctl for device */
114 }
115}
116
Chris Masonae78bf92006-09-29 02:00:03 -0700117static int fat_file_release(struct inode *inode, struct file *filp)
118{
119 if ((filp->f_mode & FMODE_WRITE) &&
120 MSDOS_SB(inode->i_sb)->options.flush) {
121 fat_flush_inodes(inode->i_sb, inode, NULL);
Andrew Morton3fcfab12006-10-19 23:28:16 -0700122 congestion_wait(WRITE, HZ/10);
Chris Masonae78bf92006-09-29 02:00:03 -0700123 }
124 return 0;
125}
126
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800127const struct file_operations fat_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 .llseek = generic_file_llseek,
129 .read = do_sync_read,
130 .write = do_sync_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 .aio_read = generic_file_aio_read,
OGAWA Hirofumief402262005-09-16 19:28:13 -0700132 .aio_write = generic_file_aio_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 .mmap = generic_file_mmap,
Chris Masonae78bf92006-09-29 02:00:03 -0700134 .release = fat_file_release,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 .ioctl = fat_generic_ioctl,
136 .fsync = file_fsync,
Jens Axboe5ffc4ef2007-06-01 11:49:19 +0200137 .splice_read = generic_file_splice_read,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138};
139
OGAWA Hirofumi05eb0b52006-01-08 01:02:13 -0800140static int fat_cont_expand(struct inode *inode, loff_t size)
141{
142 struct address_space *mapping = inode->i_mapping;
143 loff_t start = inode->i_size, count = size - inode->i_size;
144 int err;
145
146 err = generic_cont_expand_simple(inode, size);
147 if (err)
148 goto out;
149
150 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
151 mark_inode_dirty(inode);
152 if (IS_SYNC(inode))
153 err = sync_page_range_nolock(inode, mapping, start, count);
154out:
155 return err;
156}
157
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158int fat_notify_change(struct dentry *dentry, struct iattr *attr)
159{
160 struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
161 struct inode *inode = dentry->d_inode;
162 int mask, error = 0;
163
164 lock_kernel();
165
OGAWA Hirofumi05eb0b52006-01-08 01:02:13 -0800166 /*
167 * Expand the file. Since inode_setattr() updates ->i_size
168 * before calling the ->truncate(), but FAT needs to fill the
169 * hole before it.
170 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 if (attr->ia_valid & ATTR_SIZE) {
172 if (attr->ia_size > inode->i_size) {
OGAWA Hirofumi05eb0b52006-01-08 01:02:13 -0800173 error = fat_cont_expand(inode, attr->ia_size);
174 if (error || attr->ia_valid == ATTR_SIZE)
175 goto out;
176 attr->ia_valid &= ~ATTR_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177 }
178 }
179
180 error = inode_change_ok(inode, attr);
181 if (error) {
182 if (sbi->options.quiet)
183 error = 0;
184 goto out;
185 }
186 if (((attr->ia_valid & ATTR_UID) &&
187 (attr->ia_uid != sbi->options.fs_uid)) ||
188 ((attr->ia_valid & ATTR_GID) &&
189 (attr->ia_gid != sbi->options.fs_gid)) ||
190 ((attr->ia_valid & ATTR_MODE) &&
191 (attr->ia_mode & ~MSDOS_VALID_MODE)))
192 error = -EPERM;
193
194 if (error) {
195 if (sbi->options.quiet)
196 error = 0;
197 goto out;
198 }
199 error = inode_setattr(inode, attr);
200 if (error)
201 goto out;
202
203 if (S_ISDIR(inode->i_mode))
204 mask = sbi->options.fs_dmask;
205 else
206 mask = sbi->options.fs_fmask;
207 inode->i_mode &= S_IFMT | (S_IRWXUGO & ~mask);
208out:
209 unlock_kernel();
210 return error;
211}
212
OGAWA Hirofumi7c709d02006-01-08 01:02:10 -0800213EXPORT_SYMBOL_GPL(fat_notify_change);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214
215/* Free all clusters after the skip'th cluster. */
216static int fat_free(struct inode *inode, int skip)
217{
218 struct super_block *sb = inode->i_sb;
219 int err, wait, free_start, i_start, i_logstart;
220
221 if (MSDOS_I(inode)->i_start == 0)
222 return 0;
223
OGAWA Hirofumi3b641402006-02-03 03:04:44 -0800224 fat_cache_inval_inode(inode);
225
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 wait = IS_DIRSYNC(inode);
OGAWA Hirofumi3b641402006-02-03 03:04:44 -0800227 i_start = free_start = MSDOS_I(inode)->i_start;
228 i_logstart = MSDOS_I(inode)->i_logstart;
229
230 /* First, we write the new file size. */
231 if (!skip) {
232 MSDOS_I(inode)->i_start = 0;
233 MSDOS_I(inode)->i_logstart = 0;
234 }
235 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
236 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
237 if (wait) {
238 err = fat_sync_inode(inode);
239 if (err) {
240 MSDOS_I(inode)->i_start = i_start;
241 MSDOS_I(inode)->i_logstart = i_logstart;
242 return err;
243 }
244 } else
245 mark_inode_dirty(inode);
246
247 /* Write a new EOF, and get the remaining cluster chain for freeing. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248 if (skip) {
249 struct fat_entry fatent;
250 int ret, fclus, dclus;
251
252 ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus);
253 if (ret < 0)
254 return ret;
255 else if (ret == FAT_ENT_EOF)
256 return 0;
257
258 fatent_init(&fatent);
259 ret = fat_ent_read(inode, &fatent, dclus);
260 if (ret == FAT_ENT_EOF) {
261 fatent_brelse(&fatent);
262 return 0;
263 } else if (ret == FAT_ENT_FREE) {
264 fat_fs_panic(sb,
265 "%s: invalid cluster chain (i_pos %lld)",
266 __FUNCTION__, MSDOS_I(inode)->i_pos);
267 ret = -EIO;
268 } else if (ret > 0) {
269 err = fat_ent_write(inode, &fatent, FAT_ENT_EOF, wait);
270 if (err)
271 ret = err;
272 }
273 fatent_brelse(&fatent);
274 if (ret < 0)
275 return ret;
276
277 free_start = ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9);
280
281 /* Freeing the remained cluster chain */
282 return fat_free_clusters(inode, free_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283}
284
285void fat_truncate(struct inode *inode)
286{
287 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
288 const unsigned int cluster_size = sbi->cluster_size;
289 int nr_clusters;
290
291 /*
292 * This protects against truncating a file bigger than it was then
293 * trying to write into the hole.
294 */
295 if (MSDOS_I(inode)->mmu_private > inode->i_size)
296 MSDOS_I(inode)->mmu_private = inode->i_size;
297
298 nr_clusters = (inode->i_size + (cluster_size - 1)) >> sbi->cluster_bits;
299
300 lock_kernel();
301 fat_free(inode, nr_clusters);
302 unlock_kernel();
Chris Masonae78bf92006-09-29 02:00:03 -0700303 fat_flush_inodes(inode->i_sb, inode, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304}
305
OGAWA Hirofumida63fc72006-11-16 01:19:28 -0800306int fat_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
307{
308 struct inode *inode = dentry->d_inode;
309 generic_fillattr(inode, stat);
310 stat->blksize = MSDOS_SB(inode->i_sb)->cluster_size;
311 return 0;
312}
313EXPORT_SYMBOL_GPL(fat_getattr);
314
Arjan van de Ven754661f2007-02-12 00:55:38 -0800315const struct inode_operations fat_file_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 .truncate = fat_truncate,
317 .setattr = fat_notify_change,
OGAWA Hirofumida63fc72006-11-16 01:19:28 -0800318 .getattr = fat_getattr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319};