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/compat.h> 8 #include <linux/cred.h> 9 #include <linux/buffer_head.h> 10 #include <linux/blkdev.h> 11 12 #include "exfat_raw.h" 13 #include "exfat_fs.h" 14 15 static int exfat_cont_expand(struct inode *inode, loff_t size) 16 { 17 struct address_space *mapping = inode->i_mapping; 18 loff_t start = i_size_read(inode), count = size - i_size_read(inode); 19 int err, err2; 20 21 err = generic_cont_expand_simple(inode, size); 22 if (err) 23 return err; 24 25 inode->i_ctime = inode->i_mtime = current_time(inode); 26 mark_inode_dirty(inode); 27 28 if (!IS_SYNC(inode)) 29 return 0; 30 31 err = filemap_fdatawrite_range(mapping, start, start + count - 1); 32 err2 = sync_mapping_buffers(mapping); 33 if (!err) 34 err = err2; 35 err2 = write_inode_now(inode, 1); 36 if (!err) 37 err = err2; 38 if (err) 39 return err; 40 41 return filemap_fdatawait_range(mapping, start, start + count - 1); 42 } 43 44 static bool exfat_allow_set_time(struct exfat_sb_info *sbi, struct inode *inode) 45 { 46 mode_t allow_utime = sbi->options.allow_utime; 47 48 if (!uid_eq(current_fsuid(), inode->i_uid)) { 49 if (in_group_p(inode->i_gid)) 50 allow_utime >>= 3; 51 if (allow_utime & MAY_WRITE) 52 return true; 53 } 54 55 /* use a default check */ 56 return false; 57 } 58 59 static int exfat_sanitize_mode(const struct exfat_sb_info *sbi, 60 struct inode *inode, umode_t *mode_ptr) 61 { 62 mode_t i_mode, mask, perm; 63 64 i_mode = inode->i_mode; 65 66 mask = (S_ISREG(i_mode) || S_ISLNK(i_mode)) ? 67 sbi->options.fs_fmask : sbi->options.fs_dmask; 68 perm = *mode_ptr & ~(S_IFMT | mask); 69 70 /* Of the r and x bits, all (subject to umask) must be present.*/ 71 if ((perm & 0555) != (i_mode & 0555)) 72 return -EPERM; 73 74 if (exfat_mode_can_hold_ro(inode)) { 75 /* 76 * Of the w bits, either all (subject to umask) or none must 77 * be present. 78 */ 79 if ((perm & 0222) && ((perm & 0222) != (0222 & ~mask))) 80 return -EPERM; 81 } else { 82 /* 83 * If exfat_mode_can_hold_ro(inode) is false, can't change 84 * w bits. 85 */ 86 if ((perm & 0222) != (0222 & ~mask)) 87 return -EPERM; 88 } 89 90 *mode_ptr &= S_IFMT | perm; 91 92 return 0; 93 } 94 95 /* resize the file length */ 96 int __exfat_truncate(struct inode *inode) 97 { 98 unsigned int num_clusters_new, num_clusters_phys; 99 unsigned int last_clu = EXFAT_FREE_CLUSTER; 100 struct exfat_chain clu; 101 struct super_block *sb = inode->i_sb; 102 struct exfat_sb_info *sbi = EXFAT_SB(sb); 103 struct exfat_inode_info *ei = EXFAT_I(inode); 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 = EXFAT_B_TO_CLU_ROUND_UP(ei->i_size_ondisk, sbi); 113 114 exfat_chain_set(&clu, ei->start_clu, num_clusters_phys, ei->flags); 115 116 if (i_size_read(inode) > 0) { 117 /* 118 * Truncate FAT chain num_clusters after the first cluster 119 * num_clusters = min(new, phys); 120 */ 121 unsigned int num_clusters = 122 min(num_clusters_new, num_clusters_phys); 123 124 /* 125 * Follow FAT chain 126 * (defensive coding - works fine even with corrupted FAT table 127 */ 128 if (clu.flags == ALLOC_NO_FAT_CHAIN) { 129 clu.dir += num_clusters; 130 clu.size -= num_clusters; 131 } else { 132 while (num_clusters > 0) { 133 last_clu = clu.dir; 134 if (exfat_get_next_cluster(sb, &(clu.dir))) 135 return -EIO; 136 137 num_clusters--; 138 clu.size--; 139 } 140 } 141 } else { 142 ei->flags = ALLOC_NO_FAT_CHAIN; 143 ei->start_clu = EXFAT_EOF_CLUSTER; 144 } 145 146 if (ei->type == TYPE_FILE) 147 ei->attr |= ATTR_ARCHIVE; 148 149 /* 150 * update the directory entry 151 * 152 * If the directory entry is updated by mark_inode_dirty(), the 153 * directory entry will be written after a writeback cycle of 154 * updating the bitmap/FAT, which may result in clusters being 155 * freed but referenced by the directory entry in the event of a 156 * sudden power failure. 157 * __exfat_write_inode() is called for directory entry, bitmap 158 * and FAT to be written in a same writeback. 159 */ 160 if (__exfat_write_inode(inode, inode_needs_sync(inode))) 161 return -EIO; 162 163 /* cut off from the FAT chain */ 164 if (ei->flags == ALLOC_FAT_CHAIN && last_clu != EXFAT_FREE_CLUSTER && 165 last_clu != EXFAT_EOF_CLUSTER) { 166 if (exfat_ent_set(sb, last_clu, EXFAT_EOF_CLUSTER)) 167 return -EIO; 168 } 169 170 /* invalidate cache and free the clusters */ 171 /* clear exfat cache */ 172 exfat_cache_inval_inode(inode); 173 174 /* hint information */ 175 ei->hint_bmap.off = EXFAT_EOF_CLUSTER; 176 ei->hint_bmap.clu = EXFAT_EOF_CLUSTER; 177 178 /* hint_stat will be used if this is directory. */ 179 ei->hint_stat.eidx = 0; 180 ei->hint_stat.clu = ei->start_clu; 181 ei->hint_femp.eidx = EXFAT_HINT_NONE; 182 183 /* free the clusters */ 184 if (exfat_free_cluster(inode, &clu)) 185 return -EIO; 186 187 return 0; 188 } 189 190 void exfat_truncate(struct inode *inode) 191 { 192 struct super_block *sb = inode->i_sb; 193 struct exfat_sb_info *sbi = EXFAT_SB(sb); 194 struct exfat_inode_info *ei = EXFAT_I(inode); 195 unsigned int blocksize = i_blocksize(inode); 196 loff_t aligned_size; 197 int err; 198 199 mutex_lock(&sbi->s_lock); 200 if (ei->start_clu == 0) { 201 /* 202 * Empty start_clu != ~0 (not allocated) 203 */ 204 exfat_fs_error(sb, "tried to truncate zeroed cluster."); 205 goto write_size; 206 } 207 208 err = __exfat_truncate(inode); 209 if (err) 210 goto write_size; 211 212 inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >> 213 inode->i_blkbits; 214 write_size: 215 aligned_size = i_size_read(inode); 216 if (aligned_size & (blocksize - 1)) { 217 aligned_size |= (blocksize - 1); 218 aligned_size++; 219 } 220 221 if (ei->i_size_ondisk > i_size_read(inode)) 222 ei->i_size_ondisk = aligned_size; 223 224 if (ei->i_size_aligned > i_size_read(inode)) 225 ei->i_size_aligned = aligned_size; 226 mutex_unlock(&sbi->s_lock); 227 } 228 229 int exfat_getattr(struct user_namespace *mnt_uerns, const struct path *path, 230 struct kstat *stat, unsigned int request_mask, 231 unsigned int query_flags) 232 { 233 struct inode *inode = d_backing_inode(path->dentry); 234 struct exfat_inode_info *ei = EXFAT_I(inode); 235 236 generic_fillattr(&init_user_ns, inode, stat); 237 exfat_truncate_atime(&stat->atime); 238 stat->result_mask |= STATX_BTIME; 239 stat->btime.tv_sec = ei->i_crtime.tv_sec; 240 stat->btime.tv_nsec = ei->i_crtime.tv_nsec; 241 stat->blksize = EXFAT_SB(inode->i_sb)->cluster_size; 242 return 0; 243 } 244 245 int exfat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, 246 struct iattr *attr) 247 { 248 struct exfat_sb_info *sbi = EXFAT_SB(dentry->d_sb); 249 struct inode *inode = dentry->d_inode; 250 unsigned int ia_valid; 251 int error; 252 253 if ((attr->ia_valid & ATTR_SIZE) && 254 attr->ia_size > i_size_read(inode)) { 255 error = exfat_cont_expand(inode, attr->ia_size); 256 if (error || attr->ia_valid == ATTR_SIZE) 257 return error; 258 attr->ia_valid &= ~ATTR_SIZE; 259 } 260 261 /* Check for setting the inode time. */ 262 ia_valid = attr->ia_valid; 263 if ((ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) && 264 exfat_allow_set_time(sbi, inode)) { 265 attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET | 266 ATTR_TIMES_SET); 267 } 268 269 error = setattr_prepare(&init_user_ns, dentry, attr); 270 attr->ia_valid = ia_valid; 271 if (error) 272 goto out; 273 274 if (((attr->ia_valid & ATTR_UID) && 275 !uid_eq(attr->ia_uid, sbi->options.fs_uid)) || 276 ((attr->ia_valid & ATTR_GID) && 277 !gid_eq(attr->ia_gid, sbi->options.fs_gid)) || 278 ((attr->ia_valid & ATTR_MODE) && 279 (attr->ia_mode & ~(S_IFREG | S_IFLNK | S_IFDIR | 0777)))) { 280 error = -EPERM; 281 goto out; 282 } 283 284 /* 285 * We don't return -EPERM here. Yes, strange, but this is too 286 * old behavior. 287 */ 288 if (attr->ia_valid & ATTR_MODE) { 289 if (exfat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0) 290 attr->ia_valid &= ~ATTR_MODE; 291 } 292 293 if (attr->ia_valid & ATTR_SIZE) 294 inode->i_mtime = inode->i_ctime = current_time(inode); 295 296 setattr_copy(&init_user_ns, inode, attr); 297 exfat_truncate_atime(&inode->i_atime); 298 299 if (attr->ia_valid & ATTR_SIZE) { 300 error = exfat_block_truncate_page(inode, attr->ia_size); 301 if (error) 302 goto out; 303 304 down_write(&EXFAT_I(inode)->truncate_lock); 305 truncate_setsize(inode, attr->ia_size); 306 307 /* 308 * __exfat_write_inode() is called from exfat_truncate(), inode 309 * is already written by it, so mark_inode_dirty() is unneeded. 310 */ 311 exfat_truncate(inode); 312 up_write(&EXFAT_I(inode)->truncate_lock); 313 } else 314 mark_inode_dirty(inode); 315 316 out: 317 return error; 318 } 319 320 static int exfat_ioctl_fitrim(struct inode *inode, unsigned long arg) 321 { 322 struct fstrim_range range; 323 int ret = 0; 324 325 if (!capable(CAP_SYS_ADMIN)) 326 return -EPERM; 327 328 if (!bdev_max_discard_sectors(inode->i_sb->s_bdev)) 329 return -EOPNOTSUPP; 330 331 if (copy_from_user(&range, (struct fstrim_range __user *)arg, sizeof(range))) 332 return -EFAULT; 333 334 range.minlen = max_t(unsigned int, range.minlen, 335 bdev_discard_granularity(inode->i_sb->s_bdev)); 336 337 ret = exfat_trim_fs(inode, &range); 338 if (ret < 0) 339 return ret; 340 341 if (copy_to_user((struct fstrim_range __user *)arg, &range, sizeof(range))) 342 return -EFAULT; 343 344 return 0; 345 } 346 347 long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 348 { 349 struct inode *inode = file_inode(filp); 350 351 switch (cmd) { 352 case FITRIM: 353 return exfat_ioctl_fitrim(inode, arg); 354 default: 355 return -ENOTTY; 356 } 357 } 358 359 #ifdef CONFIG_COMPAT 360 long exfat_compat_ioctl(struct file *filp, unsigned int cmd, 361 unsigned long arg) 362 { 363 return exfat_ioctl(filp, cmd, (unsigned long)compat_ptr(arg)); 364 } 365 #endif 366 367 int exfat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync) 368 { 369 struct inode *inode = filp->f_mapping->host; 370 int err; 371 372 err = __generic_file_fsync(filp, start, end, datasync); 373 if (err) 374 return err; 375 376 err = sync_blockdev(inode->i_sb->s_bdev); 377 if (err) 378 return err; 379 380 return blkdev_issue_flush(inode->i_sb->s_bdev); 381 } 382 383 const struct file_operations exfat_file_operations = { 384 .llseek = generic_file_llseek, 385 .read_iter = generic_file_read_iter, 386 .write_iter = generic_file_write_iter, 387 .unlocked_ioctl = exfat_ioctl, 388 #ifdef CONFIG_COMPAT 389 .compat_ioctl = exfat_compat_ioctl, 390 #endif 391 .mmap = generic_file_mmap, 392 .fsync = exfat_file_fsync, 393 .splice_read = generic_file_splice_read, 394 .splice_write = iter_file_splice_write, 395 }; 396 397 const struct inode_operations exfat_file_inode_operations = { 398 .setattr = exfat_setattr, 399 .getattr = exfat_getattr, 400 }; 401