1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd. 4 */ 5 6 #include <linux/slab.h> 7 #include <linux/cred.h> 8 #include <linux/buffer_head.h> 9 #include <linux/blkdev.h> 10 11 #include "exfat_raw.h" 12 #include "exfat_fs.h" 13 14 static int exfat_cont_expand(struct inode *inode, loff_t size) 15 { 16 struct address_space *mapping = inode->i_mapping; 17 loff_t start = i_size_read(inode), count = size - i_size_read(inode); 18 int err, err2; 19 20 err = generic_cont_expand_simple(inode, size); 21 if (err) 22 return err; 23 24 inode->i_ctime = inode->i_mtime = current_time(inode); 25 mark_inode_dirty(inode); 26 27 if (!IS_SYNC(inode)) 28 return 0; 29 30 err = filemap_fdatawrite_range(mapping, start, start + count - 1); 31 err2 = sync_mapping_buffers(mapping); 32 if (!err) 33 err = err2; 34 err2 = write_inode_now(inode, 1); 35 if (!err) 36 err = err2; 37 if (err) 38 return err; 39 40 return filemap_fdatawait_range(mapping, start, start + count - 1); 41 } 42 43 static bool exfat_allow_set_time(struct exfat_sb_info *sbi, struct inode *inode) 44 { 45 mode_t allow_utime = sbi->options.allow_utime; 46 47 if (!uid_eq(current_fsuid(), inode->i_uid)) { 48 if (in_group_p(inode->i_gid)) 49 allow_utime >>= 3; 50 if (allow_utime & MAY_WRITE) 51 return true; 52 } 53 54 /* use a default check */ 55 return false; 56 } 57 58 static int exfat_sanitize_mode(const struct exfat_sb_info *sbi, 59 struct inode *inode, umode_t *mode_ptr) 60 { 61 mode_t i_mode, mask, perm; 62 63 i_mode = inode->i_mode; 64 65 mask = (S_ISREG(i_mode) || S_ISLNK(i_mode)) ? 66 sbi->options.fs_fmask : sbi->options.fs_dmask; 67 perm = *mode_ptr & ~(S_IFMT | mask); 68 69 /* Of the r and x bits, all (subject to umask) must be present.*/ 70 if ((perm & 0555) != (i_mode & 0555)) 71 return -EPERM; 72 73 if (exfat_mode_can_hold_ro(inode)) { 74 /* 75 * Of the w bits, either all (subject to umask) or none must 76 * be present. 77 */ 78 if ((perm & 0222) && ((perm & 0222) != (0222 & ~mask))) 79 return -EPERM; 80 } else { 81 /* 82 * If exfat_mode_can_hold_ro(inode) is false, can't change 83 * w bits. 84 */ 85 if ((perm & 0222) != (0222 & ~mask)) 86 return -EPERM; 87 } 88 89 *mode_ptr &= S_IFMT | perm; 90 91 return 0; 92 } 93 94 /* resize the file length */ 95 int __exfat_truncate(struct inode *inode, loff_t new_size) 96 { 97 unsigned int num_clusters_new, num_clusters_phys; 98 unsigned int last_clu = EXFAT_FREE_CLUSTER; 99 struct exfat_chain clu; 100 struct super_block *sb = inode->i_sb; 101 struct exfat_sb_info *sbi = EXFAT_SB(sb); 102 struct exfat_inode_info *ei = EXFAT_I(inode); 103 int evict = (ei->dir.dir == DIR_DELETED) ? 1 : 0; 104 105 /* check if the given file ID is opened */ 106 if (ei->type != TYPE_FILE && ei->type != TYPE_DIR) 107 return -EPERM; 108 109 exfat_set_volume_dirty(sb); 110 111 num_clusters_new = EXFAT_B_TO_CLU_ROUND_UP(i_size_read(inode), sbi); 112 num_clusters_phys = 113 EXFAT_B_TO_CLU_ROUND_UP(EXFAT_I(inode)->i_size_ondisk, sbi); 114 115 exfat_chain_set(&clu, ei->start_clu, num_clusters_phys, ei->flags); 116 117 if (new_size > 0) { 118 /* 119 * Truncate FAT chain num_clusters after the first cluster 120 * num_clusters = min(new, phys); 121 */ 122 unsigned int num_clusters = 123 min(num_clusters_new, num_clusters_phys); 124 125 /* 126 * Follow FAT chain 127 * (defensive coding - works fine even with corrupted FAT table 128 */ 129 if (clu.flags == ALLOC_NO_FAT_CHAIN) { 130 clu.dir += num_clusters; 131 clu.size -= num_clusters; 132 } else { 133 while (num_clusters > 0) { 134 last_clu = clu.dir; 135 if (exfat_get_next_cluster(sb, &(clu.dir))) 136 return -EIO; 137 138 num_clusters--; 139 clu.size--; 140 } 141 } 142 } else { 143 ei->flags = ALLOC_NO_FAT_CHAIN; 144 ei->start_clu = EXFAT_EOF_CLUSTER; 145 } 146 147 i_size_write(inode, new_size); 148 149 if (ei->type == TYPE_FILE) 150 ei->attr |= ATTR_ARCHIVE; 151 152 /* update the directory entry */ 153 if (!evict) { 154 struct timespec64 ts; 155 struct exfat_dentry *ep, *ep2; 156 struct exfat_entry_set_cache *es; 157 int err; 158 159 es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry, 160 ES_ALL_ENTRIES); 161 if (!es) 162 return -EIO; 163 ep = exfat_get_dentry_cached(es, 0); 164 ep2 = exfat_get_dentry_cached(es, 1); 165 166 ts = current_time(inode); 167 exfat_set_entry_time(sbi, &ts, 168 &ep->dentry.file.modify_tz, 169 &ep->dentry.file.modify_time, 170 &ep->dentry.file.modify_date, 171 &ep->dentry.file.modify_time_cs); 172 ep->dentry.file.attr = cpu_to_le16(ei->attr); 173 174 /* File size should be zero if there is no cluster allocated */ 175 if (ei->start_clu == EXFAT_EOF_CLUSTER) { 176 ep2->dentry.stream.valid_size = 0; 177 ep2->dentry.stream.size = 0; 178 } else { 179 ep2->dentry.stream.valid_size = cpu_to_le64(new_size); 180 ep2->dentry.stream.size = ep2->dentry.stream.valid_size; 181 } 182 183 if (new_size == 0) { 184 /* Any directory can not be truncated to zero */ 185 WARN_ON(ei->type != TYPE_FILE); 186 187 ep2->dentry.stream.flags = ALLOC_FAT_CHAIN; 188 ep2->dentry.stream.start_clu = EXFAT_FREE_CLUSTER; 189 } 190 191 exfat_update_dir_chksum_with_entry_set(es); 192 err = exfat_free_dentry_set(es, inode_needs_sync(inode)); 193 if (err) 194 return err; 195 } 196 197 /* cut off from the FAT chain */ 198 if (ei->flags == ALLOC_FAT_CHAIN && last_clu != EXFAT_FREE_CLUSTER && 199 last_clu != EXFAT_EOF_CLUSTER) { 200 if (exfat_ent_set(sb, last_clu, EXFAT_EOF_CLUSTER)) 201 return -EIO; 202 } 203 204 /* invalidate cache and free the clusters */ 205 /* clear exfat cache */ 206 exfat_cache_inval_inode(inode); 207 208 /* hint information */ 209 ei->hint_bmap.off = EXFAT_EOF_CLUSTER; 210 ei->hint_bmap.clu = EXFAT_EOF_CLUSTER; 211 212 /* hint_stat will be used if this is directory. */ 213 ei->hint_stat.eidx = 0; 214 ei->hint_stat.clu = ei->start_clu; 215 ei->hint_femp.eidx = EXFAT_HINT_NONE; 216 217 /* free the clusters */ 218 if (exfat_free_cluster(inode, &clu)) 219 return -EIO; 220 221 exfat_clear_volume_dirty(sb); 222 223 return 0; 224 } 225 226 void exfat_truncate(struct inode *inode, loff_t size) 227 { 228 struct super_block *sb = inode->i_sb; 229 struct exfat_sb_info *sbi = EXFAT_SB(sb); 230 unsigned int blocksize = i_blocksize(inode); 231 loff_t aligned_size; 232 int err; 233 234 mutex_lock(&sbi->s_lock); 235 if (EXFAT_I(inode)->start_clu == 0) { 236 /* 237 * Empty start_clu != ~0 (not allocated) 238 */ 239 exfat_fs_error(sb, "tried to truncate zeroed cluster."); 240 goto write_size; 241 } 242 243 err = __exfat_truncate(inode, i_size_read(inode)); 244 if (err) 245 goto write_size; 246 247 inode->i_ctime = inode->i_mtime = current_time(inode); 248 if (IS_DIRSYNC(inode)) 249 exfat_sync_inode(inode); 250 else 251 mark_inode_dirty(inode); 252 253 inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size - 1)) & 254 ~(sbi->cluster_size - 1)) >> inode->i_blkbits; 255 write_size: 256 aligned_size = i_size_read(inode); 257 if (aligned_size & (blocksize - 1)) { 258 aligned_size |= (blocksize - 1); 259 aligned_size++; 260 } 261 262 if (EXFAT_I(inode)->i_size_ondisk > i_size_read(inode)) 263 EXFAT_I(inode)->i_size_ondisk = aligned_size; 264 265 if (EXFAT_I(inode)->i_size_aligned > i_size_read(inode)) 266 EXFAT_I(inode)->i_size_aligned = aligned_size; 267 mutex_unlock(&sbi->s_lock); 268 } 269 270 int exfat_getattr(struct user_namespace *mnt_uerns, const struct path *path, 271 struct kstat *stat, unsigned int request_mask, 272 unsigned int query_flags) 273 { 274 struct inode *inode = d_backing_inode(path->dentry); 275 struct exfat_inode_info *ei = EXFAT_I(inode); 276 277 generic_fillattr(&init_user_ns, inode, stat); 278 exfat_truncate_atime(&stat->atime); 279 stat->result_mask |= STATX_BTIME; 280 stat->btime.tv_sec = ei->i_crtime.tv_sec; 281 stat->btime.tv_nsec = ei->i_crtime.tv_nsec; 282 stat->blksize = EXFAT_SB(inode->i_sb)->cluster_size; 283 return 0; 284 } 285 286 int exfat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, 287 struct iattr *attr) 288 { 289 struct exfat_sb_info *sbi = EXFAT_SB(dentry->d_sb); 290 struct inode *inode = dentry->d_inode; 291 unsigned int ia_valid; 292 int error; 293 294 if ((attr->ia_valid & ATTR_SIZE) && 295 attr->ia_size > i_size_read(inode)) { 296 error = exfat_cont_expand(inode, attr->ia_size); 297 if (error || attr->ia_valid == ATTR_SIZE) 298 return error; 299 attr->ia_valid &= ~ATTR_SIZE; 300 } 301 302 /* Check for setting the inode time. */ 303 ia_valid = attr->ia_valid; 304 if ((ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) && 305 exfat_allow_set_time(sbi, inode)) { 306 attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET | 307 ATTR_TIMES_SET); 308 } 309 310 error = setattr_prepare(&init_user_ns, dentry, attr); 311 attr->ia_valid = ia_valid; 312 if (error) 313 goto out; 314 315 if (((attr->ia_valid & ATTR_UID) && 316 !uid_eq(attr->ia_uid, sbi->options.fs_uid)) || 317 ((attr->ia_valid & ATTR_GID) && 318 !gid_eq(attr->ia_gid, sbi->options.fs_gid)) || 319 ((attr->ia_valid & ATTR_MODE) && 320 (attr->ia_mode & ~(S_IFREG | S_IFLNK | S_IFDIR | 0777)))) { 321 error = -EPERM; 322 goto out; 323 } 324 325 /* 326 * We don't return -EPERM here. Yes, strange, but this is too 327 * old behavior. 328 */ 329 if (attr->ia_valid & ATTR_MODE) { 330 if (exfat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0) 331 attr->ia_valid &= ~ATTR_MODE; 332 } 333 334 if (attr->ia_valid & ATTR_SIZE) { 335 error = exfat_block_truncate_page(inode, attr->ia_size); 336 if (error) 337 goto out; 338 339 down_write(&EXFAT_I(inode)->truncate_lock); 340 truncate_setsize(inode, attr->ia_size); 341 exfat_truncate(inode, attr->ia_size); 342 up_write(&EXFAT_I(inode)->truncate_lock); 343 } 344 345 setattr_copy(&init_user_ns, inode, attr); 346 exfat_truncate_atime(&inode->i_atime); 347 mark_inode_dirty(inode); 348 349 out: 350 return error; 351 } 352 353 int exfat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync) 354 { 355 struct inode *inode = filp->f_mapping->host; 356 int err; 357 358 err = __generic_file_fsync(filp, start, end, datasync); 359 if (err) 360 return err; 361 362 err = sync_blockdev(inode->i_sb->s_bdev); 363 if (err) 364 return err; 365 366 return blkdev_issue_flush(inode->i_sb->s_bdev); 367 } 368 369 const struct file_operations exfat_file_operations = { 370 .llseek = generic_file_llseek, 371 .read_iter = generic_file_read_iter, 372 .write_iter = generic_file_write_iter, 373 .mmap = generic_file_mmap, 374 .fsync = exfat_file_fsync, 375 .splice_read = generic_file_splice_read, 376 .splice_write = iter_file_splice_write, 377 }; 378 379 const struct inode_operations exfat_file_inode_operations = { 380 .setattr = exfat_setattr, 381 .getattr = exfat_getattr, 382 }; 383