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_vol_flags(sb, VOL_DIRTY); 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; 157 158 es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry, 159 ES_ALL_ENTRIES); 160 if (!es) 161 return -EIO; 162 ep = exfat_get_dentry_cached(es, 0); 163 ep2 = exfat_get_dentry_cached(es, 1); 164 165 ts = current_time(inode); 166 exfat_set_entry_time(sbi, &ts, 167 &ep->dentry.file.modify_tz, 168 &ep->dentry.file.modify_time, 169 &ep->dentry.file.modify_date, 170 &ep->dentry.file.modify_time_cs); 171 ep->dentry.file.attr = cpu_to_le16(ei->attr); 172 173 /* File size should be zero if there is no cluster allocated */ 174 if (ei->start_clu == EXFAT_EOF_CLUSTER) { 175 ep2->dentry.stream.valid_size = 0; 176 ep2->dentry.stream.size = 0; 177 } else { 178 ep2->dentry.stream.valid_size = cpu_to_le64(new_size); 179 ep2->dentry.stream.size = ep->dentry.stream.valid_size; 180 } 181 182 if (new_size == 0) { 183 /* Any directory can not be truncated to zero */ 184 WARN_ON(ei->type != TYPE_FILE); 185 186 ep2->dentry.stream.flags = ALLOC_FAT_CHAIN; 187 ep2->dentry.stream.start_clu = EXFAT_FREE_CLUSTER; 188 } 189 190 exfat_update_dir_chksum_with_entry_set(es); 191 exfat_free_dentry_set(es, inode_needs_sync(inode)); 192 } 193 194 /* cut off from the FAT chain */ 195 if (ei->flags == ALLOC_FAT_CHAIN && last_clu != EXFAT_FREE_CLUSTER && 196 last_clu != EXFAT_EOF_CLUSTER) { 197 if (exfat_ent_set(sb, last_clu, EXFAT_EOF_CLUSTER)) 198 return -EIO; 199 } 200 201 /* invalidate cache and free the clusters */ 202 /* clear exfat cache */ 203 exfat_cache_inval_inode(inode); 204 205 /* hint information */ 206 ei->hint_bmap.off = EXFAT_EOF_CLUSTER; 207 ei->hint_bmap.clu = EXFAT_EOF_CLUSTER; 208 if (ei->rwoffset > new_size) 209 ei->rwoffset = new_size; 210 211 /* hint_stat will be used if this is directory. */ 212 ei->hint_stat.eidx = 0; 213 ei->hint_stat.clu = ei->start_clu; 214 ei->hint_femp.eidx = EXFAT_HINT_NONE; 215 216 /* free the clusters */ 217 if (exfat_free_cluster(inode, &clu)) 218 return -EIO; 219 220 exfat_set_vol_flags(sb, VOL_CLEAN); 221 222 return 0; 223 } 224 225 void exfat_truncate(struct inode *inode, loff_t size) 226 { 227 struct super_block *sb = inode->i_sb; 228 struct exfat_sb_info *sbi = EXFAT_SB(sb); 229 unsigned int blocksize = 1 << inode->i_blkbits; 230 loff_t aligned_size; 231 int err; 232 233 mutex_lock(&sbi->s_lock); 234 if (EXFAT_I(inode)->start_clu == 0) { 235 /* 236 * Empty start_clu != ~0 (not allocated) 237 */ 238 exfat_fs_error(sb, "tried to truncate zeroed cluster."); 239 goto write_size; 240 } 241 242 err = __exfat_truncate(inode, i_size_read(inode)); 243 if (err) 244 goto write_size; 245 246 inode->i_ctime = inode->i_mtime = current_time(inode); 247 if (IS_DIRSYNC(inode)) 248 exfat_sync_inode(inode); 249 else 250 mark_inode_dirty(inode); 251 252 inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size - 1)) & 253 ~(sbi->cluster_size - 1)) >> inode->i_blkbits; 254 write_size: 255 aligned_size = i_size_read(inode); 256 if (aligned_size & (blocksize - 1)) { 257 aligned_size |= (blocksize - 1); 258 aligned_size++; 259 } 260 261 if (EXFAT_I(inode)->i_size_ondisk > i_size_read(inode)) 262 EXFAT_I(inode)->i_size_ondisk = aligned_size; 263 264 if (EXFAT_I(inode)->i_size_aligned > i_size_read(inode)) 265 EXFAT_I(inode)->i_size_aligned = aligned_size; 266 mutex_unlock(&sbi->s_lock); 267 } 268 269 int exfat_getattr(const struct path *path, struct kstat *stat, 270 unsigned int request_mask, unsigned int query_flags) 271 { 272 struct inode *inode = d_backing_inode(path->dentry); 273 struct exfat_inode_info *ei = EXFAT_I(inode); 274 275 generic_fillattr(inode, stat); 276 exfat_truncate_atime(&stat->atime); 277 stat->result_mask |= STATX_BTIME; 278 stat->btime.tv_sec = ei->i_crtime.tv_sec; 279 stat->btime.tv_nsec = ei->i_crtime.tv_nsec; 280 stat->blksize = EXFAT_SB(inode->i_sb)->cluster_size; 281 return 0; 282 } 283 284 int exfat_setattr(struct dentry *dentry, struct iattr *attr) 285 { 286 struct exfat_sb_info *sbi = EXFAT_SB(dentry->d_sb); 287 struct inode *inode = dentry->d_inode; 288 unsigned int ia_valid; 289 int error; 290 291 if ((attr->ia_valid & ATTR_SIZE) && 292 attr->ia_size > i_size_read(inode)) { 293 error = exfat_cont_expand(inode, attr->ia_size); 294 if (error || attr->ia_valid == ATTR_SIZE) 295 return error; 296 attr->ia_valid &= ~ATTR_SIZE; 297 } 298 299 /* Check for setting the inode time. */ 300 ia_valid = attr->ia_valid; 301 if ((ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) && 302 exfat_allow_set_time(sbi, inode)) { 303 attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET | 304 ATTR_TIMES_SET); 305 } 306 307 error = setattr_prepare(dentry, attr); 308 attr->ia_valid = ia_valid; 309 if (error) 310 goto out; 311 312 if (((attr->ia_valid & ATTR_UID) && 313 !uid_eq(attr->ia_uid, sbi->options.fs_uid)) || 314 ((attr->ia_valid & ATTR_GID) && 315 !gid_eq(attr->ia_gid, sbi->options.fs_gid)) || 316 ((attr->ia_valid & ATTR_MODE) && 317 (attr->ia_mode & ~(S_IFREG | S_IFLNK | S_IFDIR | 0777)))) { 318 error = -EPERM; 319 goto out; 320 } 321 322 /* 323 * We don't return -EPERM here. Yes, strange, but this is too 324 * old behavior. 325 */ 326 if (attr->ia_valid & ATTR_MODE) { 327 if (exfat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0) 328 attr->ia_valid &= ~ATTR_MODE; 329 } 330 331 if (attr->ia_valid & ATTR_SIZE) { 332 error = exfat_block_truncate_page(inode, attr->ia_size); 333 if (error) 334 goto out; 335 336 down_write(&EXFAT_I(inode)->truncate_lock); 337 truncate_setsize(inode, attr->ia_size); 338 exfat_truncate(inode, attr->ia_size); 339 up_write(&EXFAT_I(inode)->truncate_lock); 340 } 341 342 setattr_copy(inode, attr); 343 exfat_truncate_atime(&inode->i_atime); 344 mark_inode_dirty(inode); 345 346 out: 347 return error; 348 } 349 350 int exfat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync) 351 { 352 struct inode *inode = filp->f_mapping->host; 353 int err; 354 355 err = __generic_file_fsync(filp, start, end, datasync); 356 if (err) 357 return err; 358 359 err = sync_blockdev(inode->i_sb->s_bdev); 360 if (err) 361 return err; 362 363 return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL); 364 } 365 366 const struct file_operations exfat_file_operations = { 367 .llseek = generic_file_llseek, 368 .read_iter = generic_file_read_iter, 369 .write_iter = generic_file_write_iter, 370 .mmap = generic_file_mmap, 371 .fsync = exfat_file_fsync, 372 .splice_read = generic_file_splice_read, 373 .splice_write = iter_file_splice_write, 374 }; 375 376 const struct inode_operations exfat_file_inode_operations = { 377 .setattr = exfat_setattr, 378 .getattr = exfat_getattr, 379 }; 380