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 9 #include <linux/module.h> 10 #include <linux/time.h> 11 #include <linux/msdos_fs.h> 12 #include <linux/smp_lock.h> 13 #include <linux/buffer_head.h> 14 15 static ssize_t fat_file_aio_write(struct kiocb *iocb, const char __user *buf, 16 size_t count, loff_t pos) 17 { 18 struct inode *inode = iocb->ki_filp->f_dentry->d_inode; 19 int retval; 20 21 retval = generic_file_aio_write(iocb, buf, count, pos); 22 if (retval > 0) { 23 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; 24 MSDOS_I(inode)->i_attrs |= ATTR_ARCH; 25 mark_inode_dirty(inode); 26 // check the locking rules 27 // if (IS_SYNC(inode)) 28 // fat_sync_inode(inode); 29 } 30 return retval; 31 } 32 33 static ssize_t fat_file_writev(struct file *filp, const struct iovec *iov, 34 unsigned long nr_segs, loff_t *ppos) 35 { 36 struct inode *inode = filp->f_dentry->d_inode; 37 int retval; 38 39 retval = generic_file_writev(filp, iov, nr_segs, ppos); 40 if (retval > 0) { 41 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; 42 MSDOS_I(inode)->i_attrs |= ATTR_ARCH; 43 mark_inode_dirty(inode); 44 } 45 return retval; 46 } 47 48 int fat_generic_ioctl(struct inode *inode, struct file *filp, 49 unsigned int cmd, unsigned long arg) 50 { 51 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 52 u32 __user *user_attr = (u32 __user *)arg; 53 54 switch (cmd) { 55 case FAT_IOCTL_GET_ATTRIBUTES: 56 { 57 u32 attr; 58 59 if (inode->i_ino == MSDOS_ROOT_INO) 60 attr = ATTR_DIR; 61 else 62 attr = fat_attr(inode); 63 64 return put_user(attr, user_attr); 65 } 66 case FAT_IOCTL_SET_ATTRIBUTES: 67 { 68 u32 attr, oldattr; 69 int err, is_dir = S_ISDIR(inode->i_mode); 70 struct iattr ia; 71 72 err = get_user(attr, user_attr); 73 if (err) 74 return err; 75 76 down(&inode->i_sem); 77 78 if (IS_RDONLY(inode)) { 79 err = -EROFS; 80 goto up; 81 } 82 83 /* 84 * ATTR_VOLUME and ATTR_DIR cannot be changed; this also 85 * prevents the user from turning us into a VFAT 86 * longname entry. Also, we obviously can't set 87 * any of the NTFS attributes in the high 24 bits. 88 */ 89 attr &= 0xff & ~(ATTR_VOLUME | ATTR_DIR); 90 /* Merge in ATTR_VOLUME and ATTR_DIR */ 91 attr |= (MSDOS_I(inode)->i_attrs & ATTR_VOLUME) | 92 (is_dir ? ATTR_DIR : 0); 93 oldattr = fat_attr(inode); 94 95 /* Equivalent to a chmod() */ 96 ia.ia_valid = ATTR_MODE | ATTR_CTIME; 97 if (is_dir) { 98 ia.ia_mode = MSDOS_MKMODE(attr, 99 S_IRWXUGO & ~sbi->options.fs_dmask) 100 | S_IFDIR; 101 } else { 102 ia.ia_mode = MSDOS_MKMODE(attr, 103 (S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO)) 104 & ~sbi->options.fs_fmask) 105 | S_IFREG; 106 } 107 108 /* The root directory has no attributes */ 109 if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) { 110 err = -EINVAL; 111 goto up; 112 } 113 114 if (sbi->options.sys_immutable) { 115 if ((attr | oldattr) & ATTR_SYS) { 116 if (!capable(CAP_LINUX_IMMUTABLE)) { 117 err = -EPERM; 118 goto up; 119 } 120 } 121 } 122 123 /* This MUST be done before doing anything irreversible... */ 124 err = notify_change(filp->f_dentry, &ia); 125 if (err) 126 goto up; 127 128 if (sbi->options.sys_immutable) { 129 if (attr & ATTR_SYS) 130 inode->i_flags |= S_IMMUTABLE; 131 else 132 inode->i_flags &= S_IMMUTABLE; 133 } 134 135 MSDOS_I(inode)->i_attrs = attr & ATTR_UNUSED; 136 mark_inode_dirty(inode); 137 up: 138 up(&inode->i_sem); 139 return err; 140 } 141 default: 142 return -ENOTTY; /* Inappropriate ioctl for device */ 143 } 144 } 145 146 struct file_operations fat_file_operations = { 147 .llseek = generic_file_llseek, 148 .read = do_sync_read, 149 .write = do_sync_write, 150 .readv = generic_file_readv, 151 .writev = fat_file_writev, 152 .aio_read = generic_file_aio_read, 153 .aio_write = fat_file_aio_write, 154 .mmap = generic_file_mmap, 155 .ioctl = fat_generic_ioctl, 156 .fsync = file_fsync, 157 .sendfile = generic_file_sendfile, 158 }; 159 160 int fat_notify_change(struct dentry *dentry, struct iattr *attr) 161 { 162 struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb); 163 struct inode *inode = dentry->d_inode; 164 int mask, error = 0; 165 166 lock_kernel(); 167 168 /* FAT cannot truncate to a longer file */ 169 if (attr->ia_valid & ATTR_SIZE) { 170 if (attr->ia_size > inode->i_size) { 171 error = -EPERM; 172 goto out; 173 } 174 } 175 176 error = inode_change_ok(inode, attr); 177 if (error) { 178 if (sbi->options.quiet) 179 error = 0; 180 goto out; 181 } 182 if (((attr->ia_valid & ATTR_UID) && 183 (attr->ia_uid != sbi->options.fs_uid)) || 184 ((attr->ia_valid & ATTR_GID) && 185 (attr->ia_gid != sbi->options.fs_gid)) || 186 ((attr->ia_valid & ATTR_MODE) && 187 (attr->ia_mode & ~MSDOS_VALID_MODE))) 188 error = -EPERM; 189 190 if (error) { 191 if (sbi->options.quiet) 192 error = 0; 193 goto out; 194 } 195 error = inode_setattr(inode, attr); 196 if (error) 197 goto out; 198 199 if (S_ISDIR(inode->i_mode)) 200 mask = sbi->options.fs_dmask; 201 else 202 mask = sbi->options.fs_fmask; 203 inode->i_mode &= S_IFMT | (S_IRWXUGO & ~mask); 204 out: 205 unlock_kernel(); 206 return error; 207 } 208 209 EXPORT_SYMBOL(fat_notify_change); 210 211 /* Free all clusters after the skip'th cluster. */ 212 static int fat_free(struct inode *inode, int skip) 213 { 214 struct super_block *sb = inode->i_sb; 215 int err, wait, free_start, i_start, i_logstart; 216 217 if (MSDOS_I(inode)->i_start == 0) 218 return 0; 219 220 /* 221 * Write a new EOF, and get the remaining cluster chain for freeing. 222 */ 223 wait = IS_DIRSYNC(inode); 224 if (skip) { 225 struct fat_entry fatent; 226 int ret, fclus, dclus; 227 228 ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus); 229 if (ret < 0) 230 return ret; 231 else if (ret == FAT_ENT_EOF) 232 return 0; 233 234 fatent_init(&fatent); 235 ret = fat_ent_read(inode, &fatent, dclus); 236 if (ret == FAT_ENT_EOF) { 237 fatent_brelse(&fatent); 238 return 0; 239 } else if (ret == FAT_ENT_FREE) { 240 fat_fs_panic(sb, 241 "%s: invalid cluster chain (i_pos %lld)", 242 __FUNCTION__, MSDOS_I(inode)->i_pos); 243 ret = -EIO; 244 } else if (ret > 0) { 245 err = fat_ent_write(inode, &fatent, FAT_ENT_EOF, wait); 246 if (err) 247 ret = err; 248 } 249 fatent_brelse(&fatent); 250 if (ret < 0) 251 return ret; 252 253 free_start = ret; 254 i_start = i_logstart = 0; 255 fat_cache_inval_inode(inode); 256 } else { 257 fat_cache_inval_inode(inode); 258 259 i_start = free_start = MSDOS_I(inode)->i_start; 260 i_logstart = MSDOS_I(inode)->i_logstart; 261 MSDOS_I(inode)->i_start = 0; 262 MSDOS_I(inode)->i_logstart = 0; 263 } 264 MSDOS_I(inode)->i_attrs |= ATTR_ARCH; 265 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; 266 if (wait) { 267 err = fat_sync_inode(inode); 268 if (err) 269 goto error; 270 } else 271 mark_inode_dirty(inode); 272 inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9); 273 274 /* Freeing the remained cluster chain */ 275 return fat_free_clusters(inode, free_start); 276 277 error: 278 if (i_start) { 279 MSDOS_I(inode)->i_start = i_start; 280 MSDOS_I(inode)->i_logstart = i_logstart; 281 } 282 return err; 283 } 284 285 void 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(); 303 } 304 305 struct inode_operations fat_file_inode_operations = { 306 .truncate = fat_truncate, 307 .setattr = fat_notify_change, 308 }; 309