1 /* 2 * hugetlbpage-backed filesystem. Based on ramfs. 3 * 4 * Nadia Yvette Chambers, 2002 5 * 6 * Copyright (C) 2002 Linus Torvalds. 7 * License: GPL 8 */ 9 10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 11 12 #include <linux/thread_info.h> 13 #include <asm/current.h> 14 #include <linux/falloc.h> 15 #include <linux/fs.h> 16 #include <linux/mount.h> 17 #include <linux/file.h> 18 #include <linux/kernel.h> 19 #include <linux/writeback.h> 20 #include <linux/pagemap.h> 21 #include <linux/highmem.h> 22 #include <linux/init.h> 23 #include <linux/string.h> 24 #include <linux/capability.h> 25 #include <linux/ctype.h> 26 #include <linux/backing-dev.h> 27 #include <linux/hugetlb.h> 28 #include <linux/pagevec.h> 29 #include <linux/fs_parser.h> 30 #include <linux/mman.h> 31 #include <linux/slab.h> 32 #include <linux/dnotify.h> 33 #include <linux/statfs.h> 34 #include <linux/security.h> 35 #include <linux/magic.h> 36 #include <linux/migrate.h> 37 #include <linux/uio.h> 38 39 #include <linux/uaccess.h> 40 #include <linux/sched/mm.h> 41 42 static const struct address_space_operations hugetlbfs_aops; 43 const struct file_operations hugetlbfs_file_operations; 44 static const struct inode_operations hugetlbfs_dir_inode_operations; 45 static const struct inode_operations hugetlbfs_inode_operations; 46 47 enum hugetlbfs_size_type { NO_SIZE, SIZE_STD, SIZE_PERCENT }; 48 49 struct hugetlbfs_fs_context { 50 struct hstate *hstate; 51 unsigned long long max_size_opt; 52 unsigned long long min_size_opt; 53 long max_hpages; 54 long nr_inodes; 55 long min_hpages; 56 enum hugetlbfs_size_type max_val_type; 57 enum hugetlbfs_size_type min_val_type; 58 kuid_t uid; 59 kgid_t gid; 60 umode_t mode; 61 }; 62 63 int sysctl_hugetlb_shm_group; 64 65 enum hugetlb_param { 66 Opt_gid, 67 Opt_min_size, 68 Opt_mode, 69 Opt_nr_inodes, 70 Opt_pagesize, 71 Opt_size, 72 Opt_uid, 73 }; 74 75 static const struct fs_parameter_spec hugetlb_fs_parameters[] = { 76 fsparam_u32 ("gid", Opt_gid), 77 fsparam_string("min_size", Opt_min_size), 78 fsparam_u32oct("mode", Opt_mode), 79 fsparam_string("nr_inodes", Opt_nr_inodes), 80 fsparam_string("pagesize", Opt_pagesize), 81 fsparam_string("size", Opt_size), 82 fsparam_u32 ("uid", Opt_uid), 83 {} 84 }; 85 86 #ifdef CONFIG_NUMA 87 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma, 88 struct inode *inode, pgoff_t index) 89 { 90 vma->vm_policy = mpol_shared_policy_lookup(&HUGETLBFS_I(inode)->policy, 91 index); 92 } 93 94 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma) 95 { 96 mpol_cond_put(vma->vm_policy); 97 } 98 #else 99 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma, 100 struct inode *inode, pgoff_t index) 101 { 102 } 103 104 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma) 105 { 106 } 107 #endif 108 109 /* 110 * Mask used when checking the page offset value passed in via system 111 * calls. This value will be converted to a loff_t which is signed. 112 * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the 113 * value. The extra bit (- 1 in the shift value) is to take the sign 114 * bit into account. 115 */ 116 #define PGOFF_LOFFT_MAX \ 117 (((1UL << (PAGE_SHIFT + 1)) - 1) << (BITS_PER_LONG - (PAGE_SHIFT + 1))) 118 119 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma) 120 { 121 struct inode *inode = file_inode(file); 122 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode); 123 loff_t len, vma_len; 124 int ret; 125 struct hstate *h = hstate_file(file); 126 127 /* 128 * vma address alignment (but not the pgoff alignment) has 129 * already been checked by prepare_hugepage_range. If you add 130 * any error returns here, do so after setting VM_HUGETLB, so 131 * is_vm_hugetlb_page tests below unmap_region go the right 132 * way when do_mmap unwinds (may be important on powerpc 133 * and ia64). 134 */ 135 vm_flags_set(vma, VM_HUGETLB | VM_DONTEXPAND); 136 vma->vm_ops = &hugetlb_vm_ops; 137 138 ret = seal_check_future_write(info->seals, vma); 139 if (ret) 140 return ret; 141 142 /* 143 * page based offset in vm_pgoff could be sufficiently large to 144 * overflow a loff_t when converted to byte offset. This can 145 * only happen on architectures where sizeof(loff_t) == 146 * sizeof(unsigned long). So, only check in those instances. 147 */ 148 if (sizeof(unsigned long) == sizeof(loff_t)) { 149 if (vma->vm_pgoff & PGOFF_LOFFT_MAX) 150 return -EINVAL; 151 } 152 153 /* must be huge page aligned */ 154 if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT)) 155 return -EINVAL; 156 157 vma_len = (loff_t)(vma->vm_end - vma->vm_start); 158 len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); 159 /* check for overflow */ 160 if (len < vma_len) 161 return -EINVAL; 162 163 inode_lock(inode); 164 file_accessed(file); 165 166 ret = -ENOMEM; 167 if (!hugetlb_reserve_pages(inode, 168 vma->vm_pgoff >> huge_page_order(h), 169 len >> huge_page_shift(h), vma, 170 vma->vm_flags)) 171 goto out; 172 173 ret = 0; 174 if (vma->vm_flags & VM_WRITE && inode->i_size < len) 175 i_size_write(inode, len); 176 out: 177 inode_unlock(inode); 178 179 return ret; 180 } 181 182 /* 183 * Called under mmap_write_lock(mm). 184 */ 185 186 static unsigned long 187 hugetlb_get_unmapped_area_bottomup(struct file *file, unsigned long addr, 188 unsigned long len, unsigned long pgoff, unsigned long flags) 189 { 190 struct hstate *h = hstate_file(file); 191 struct vm_unmapped_area_info info; 192 193 info.flags = 0; 194 info.length = len; 195 info.low_limit = current->mm->mmap_base; 196 info.high_limit = arch_get_mmap_end(addr, len, flags); 197 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 198 info.align_offset = 0; 199 return vm_unmapped_area(&info); 200 } 201 202 static unsigned long 203 hugetlb_get_unmapped_area_topdown(struct file *file, unsigned long addr, 204 unsigned long len, unsigned long pgoff, unsigned long flags) 205 { 206 struct hstate *h = hstate_file(file); 207 struct vm_unmapped_area_info info; 208 209 info.flags = VM_UNMAPPED_AREA_TOPDOWN; 210 info.length = len; 211 info.low_limit = PAGE_SIZE; 212 info.high_limit = arch_get_mmap_base(addr, current->mm->mmap_base); 213 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 214 info.align_offset = 0; 215 addr = vm_unmapped_area(&info); 216 217 /* 218 * A failed mmap() very likely causes application failure, 219 * so fall back to the bottom-up function here. This scenario 220 * can happen with large stack limits and large mmap() 221 * allocations. 222 */ 223 if (unlikely(offset_in_page(addr))) { 224 VM_BUG_ON(addr != -ENOMEM); 225 info.flags = 0; 226 info.low_limit = current->mm->mmap_base; 227 info.high_limit = arch_get_mmap_end(addr, len, flags); 228 addr = vm_unmapped_area(&info); 229 } 230 231 return addr; 232 } 233 234 unsigned long 235 generic_hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 236 unsigned long len, unsigned long pgoff, 237 unsigned long flags) 238 { 239 struct mm_struct *mm = current->mm; 240 struct vm_area_struct *vma; 241 struct hstate *h = hstate_file(file); 242 const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); 243 244 if (len & ~huge_page_mask(h)) 245 return -EINVAL; 246 if (len > TASK_SIZE) 247 return -ENOMEM; 248 249 if (flags & MAP_FIXED) { 250 if (prepare_hugepage_range(file, addr, len)) 251 return -EINVAL; 252 return addr; 253 } 254 255 if (addr) { 256 addr = ALIGN(addr, huge_page_size(h)); 257 vma = find_vma(mm, addr); 258 if (mmap_end - len >= addr && 259 (!vma || addr + len <= vm_start_gap(vma))) 260 return addr; 261 } 262 263 /* 264 * Use mm->get_unmapped_area value as a hint to use topdown routine. 265 * If architectures have special needs, they should define their own 266 * version of hugetlb_get_unmapped_area. 267 */ 268 if (mm->get_unmapped_area == arch_get_unmapped_area_topdown) 269 return hugetlb_get_unmapped_area_topdown(file, addr, len, 270 pgoff, flags); 271 return hugetlb_get_unmapped_area_bottomup(file, addr, len, 272 pgoff, flags); 273 } 274 275 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA 276 static unsigned long 277 hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 278 unsigned long len, unsigned long pgoff, 279 unsigned long flags) 280 { 281 return generic_hugetlb_get_unmapped_area(file, addr, len, pgoff, flags); 282 } 283 #endif 284 285 /* 286 * Support for read() - Find the page attached to f_mapping and copy out the 287 * data. This provides functionality similar to filemap_read(). 288 */ 289 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to) 290 { 291 struct file *file = iocb->ki_filp; 292 struct hstate *h = hstate_file(file); 293 struct address_space *mapping = file->f_mapping; 294 struct inode *inode = mapping->host; 295 unsigned long index = iocb->ki_pos >> huge_page_shift(h); 296 unsigned long offset = iocb->ki_pos & ~huge_page_mask(h); 297 unsigned long end_index; 298 loff_t isize; 299 ssize_t retval = 0; 300 301 while (iov_iter_count(to)) { 302 struct page *page; 303 size_t nr, copied; 304 305 /* nr is the maximum number of bytes to copy from this page */ 306 nr = huge_page_size(h); 307 isize = i_size_read(inode); 308 if (!isize) 309 break; 310 end_index = (isize - 1) >> huge_page_shift(h); 311 if (index > end_index) 312 break; 313 if (index == end_index) { 314 nr = ((isize - 1) & ~huge_page_mask(h)) + 1; 315 if (nr <= offset) 316 break; 317 } 318 nr = nr - offset; 319 320 /* Find the page */ 321 page = find_lock_page(mapping, index); 322 if (unlikely(page == NULL)) { 323 /* 324 * We have a HOLE, zero out the user-buffer for the 325 * length of the hole or request. 326 */ 327 copied = iov_iter_zero(nr, to); 328 } else { 329 unlock_page(page); 330 331 if (PageHWPoison(page)) { 332 put_page(page); 333 retval = -EIO; 334 break; 335 } 336 337 /* 338 * We have the page, copy it to user space buffer. 339 */ 340 copied = copy_page_to_iter(page, offset, nr, to); 341 put_page(page); 342 } 343 offset += copied; 344 retval += copied; 345 if (copied != nr && iov_iter_count(to)) { 346 if (!retval) 347 retval = -EFAULT; 348 break; 349 } 350 index += offset >> huge_page_shift(h); 351 offset &= ~huge_page_mask(h); 352 } 353 iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset; 354 return retval; 355 } 356 357 static int hugetlbfs_write_begin(struct file *file, 358 struct address_space *mapping, 359 loff_t pos, unsigned len, 360 struct page **pagep, void **fsdata) 361 { 362 return -EINVAL; 363 } 364 365 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping, 366 loff_t pos, unsigned len, unsigned copied, 367 struct page *page, void *fsdata) 368 { 369 BUG(); 370 return -EINVAL; 371 } 372 373 static void hugetlb_delete_from_page_cache(struct folio *folio) 374 { 375 folio_clear_dirty(folio); 376 folio_clear_uptodate(folio); 377 filemap_remove_folio(folio); 378 } 379 380 /* 381 * Called with i_mmap_rwsem held for inode based vma maps. This makes 382 * sure vma (and vm_mm) will not go away. We also hold the hugetlb fault 383 * mutex for the page in the mapping. So, we can not race with page being 384 * faulted into the vma. 385 */ 386 static bool hugetlb_vma_maps_page(struct vm_area_struct *vma, 387 unsigned long addr, struct page *page) 388 { 389 pte_t *ptep, pte; 390 391 ptep = hugetlb_walk(vma, addr, huge_page_size(hstate_vma(vma))); 392 if (!ptep) 393 return false; 394 395 pte = huge_ptep_get(ptep); 396 if (huge_pte_none(pte) || !pte_present(pte)) 397 return false; 398 399 if (pte_page(pte) == page) 400 return true; 401 402 return false; 403 } 404 405 /* 406 * Can vma_offset_start/vma_offset_end overflow on 32-bit arches? 407 * No, because the interval tree returns us only those vmas 408 * which overlap the truncated area starting at pgoff, 409 * and no vma on a 32-bit arch can span beyond the 4GB. 410 */ 411 static unsigned long vma_offset_start(struct vm_area_struct *vma, pgoff_t start) 412 { 413 unsigned long offset = 0; 414 415 if (vma->vm_pgoff < start) 416 offset = (start - vma->vm_pgoff) << PAGE_SHIFT; 417 418 return vma->vm_start + offset; 419 } 420 421 static unsigned long vma_offset_end(struct vm_area_struct *vma, pgoff_t end) 422 { 423 unsigned long t_end; 424 425 if (!end) 426 return vma->vm_end; 427 428 t_end = ((end - vma->vm_pgoff) << PAGE_SHIFT) + vma->vm_start; 429 if (t_end > vma->vm_end) 430 t_end = vma->vm_end; 431 return t_end; 432 } 433 434 /* 435 * Called with hugetlb fault mutex held. Therefore, no more mappings to 436 * this folio can be created while executing the routine. 437 */ 438 static void hugetlb_unmap_file_folio(struct hstate *h, 439 struct address_space *mapping, 440 struct folio *folio, pgoff_t index) 441 { 442 struct rb_root_cached *root = &mapping->i_mmap; 443 struct hugetlb_vma_lock *vma_lock; 444 struct page *page = &folio->page; 445 struct vm_area_struct *vma; 446 unsigned long v_start; 447 unsigned long v_end; 448 pgoff_t start, end; 449 450 start = index * pages_per_huge_page(h); 451 end = (index + 1) * pages_per_huge_page(h); 452 453 i_mmap_lock_write(mapping); 454 retry: 455 vma_lock = NULL; 456 vma_interval_tree_foreach(vma, root, start, end - 1) { 457 v_start = vma_offset_start(vma, start); 458 v_end = vma_offset_end(vma, end); 459 460 if (!hugetlb_vma_maps_page(vma, v_start, page)) 461 continue; 462 463 if (!hugetlb_vma_trylock_write(vma)) { 464 vma_lock = vma->vm_private_data; 465 /* 466 * If we can not get vma lock, we need to drop 467 * immap_sema and take locks in order. First, 468 * take a ref on the vma_lock structure so that 469 * we can be guaranteed it will not go away when 470 * dropping immap_sema. 471 */ 472 kref_get(&vma_lock->refs); 473 break; 474 } 475 476 unmap_hugepage_range(vma, v_start, v_end, NULL, 477 ZAP_FLAG_DROP_MARKER); 478 hugetlb_vma_unlock_write(vma); 479 } 480 481 i_mmap_unlock_write(mapping); 482 483 if (vma_lock) { 484 /* 485 * Wait on vma_lock. We know it is still valid as we have 486 * a reference. We must 'open code' vma locking as we do 487 * not know if vma_lock is still attached to vma. 488 */ 489 down_write(&vma_lock->rw_sema); 490 i_mmap_lock_write(mapping); 491 492 vma = vma_lock->vma; 493 if (!vma) { 494 /* 495 * If lock is no longer attached to vma, then just 496 * unlock, drop our reference and retry looking for 497 * other vmas. 498 */ 499 up_write(&vma_lock->rw_sema); 500 kref_put(&vma_lock->refs, hugetlb_vma_lock_release); 501 goto retry; 502 } 503 504 /* 505 * vma_lock is still attached to vma. Check to see if vma 506 * still maps page and if so, unmap. 507 */ 508 v_start = vma_offset_start(vma, start); 509 v_end = vma_offset_end(vma, end); 510 if (hugetlb_vma_maps_page(vma, v_start, page)) 511 unmap_hugepage_range(vma, v_start, v_end, NULL, 512 ZAP_FLAG_DROP_MARKER); 513 514 kref_put(&vma_lock->refs, hugetlb_vma_lock_release); 515 hugetlb_vma_unlock_write(vma); 516 517 goto retry; 518 } 519 } 520 521 static void 522 hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end, 523 zap_flags_t zap_flags) 524 { 525 struct vm_area_struct *vma; 526 527 /* 528 * end == 0 indicates that the entire range after start should be 529 * unmapped. Note, end is exclusive, whereas the interval tree takes 530 * an inclusive "last". 531 */ 532 vma_interval_tree_foreach(vma, root, start, end ? end - 1 : ULONG_MAX) { 533 unsigned long v_start; 534 unsigned long v_end; 535 536 if (!hugetlb_vma_trylock_write(vma)) 537 continue; 538 539 v_start = vma_offset_start(vma, start); 540 v_end = vma_offset_end(vma, end); 541 542 unmap_hugepage_range(vma, v_start, v_end, NULL, zap_flags); 543 544 /* 545 * Note that vma lock only exists for shared/non-private 546 * vmas. Therefore, lock is not held when calling 547 * unmap_hugepage_range for private vmas. 548 */ 549 hugetlb_vma_unlock_write(vma); 550 } 551 } 552 553 /* 554 * Called with hugetlb fault mutex held. 555 * Returns true if page was actually removed, false otherwise. 556 */ 557 static bool remove_inode_single_folio(struct hstate *h, struct inode *inode, 558 struct address_space *mapping, 559 struct folio *folio, pgoff_t index, 560 bool truncate_op) 561 { 562 bool ret = false; 563 564 /* 565 * If folio is mapped, it was faulted in after being 566 * unmapped in caller. Unmap (again) while holding 567 * the fault mutex. The mutex will prevent faults 568 * until we finish removing the folio. 569 */ 570 if (unlikely(folio_mapped(folio))) 571 hugetlb_unmap_file_folio(h, mapping, folio, index); 572 573 folio_lock(folio); 574 /* 575 * We must remove the folio from page cache before removing 576 * the region/ reserve map (hugetlb_unreserve_pages). In 577 * rare out of memory conditions, removal of the region/reserve 578 * map could fail. Correspondingly, the subpool and global 579 * reserve usage count can need to be adjusted. 580 */ 581 VM_BUG_ON_FOLIO(folio_test_hugetlb_restore_reserve(folio), folio); 582 hugetlb_delete_from_page_cache(folio); 583 ret = true; 584 if (!truncate_op) { 585 if (unlikely(hugetlb_unreserve_pages(inode, index, 586 index + 1, 1))) 587 hugetlb_fix_reserve_counts(inode); 588 } 589 590 folio_unlock(folio); 591 return ret; 592 } 593 594 /* 595 * remove_inode_hugepages handles two distinct cases: truncation and hole 596 * punch. There are subtle differences in operation for each case. 597 * 598 * truncation is indicated by end of range being LLONG_MAX 599 * In this case, we first scan the range and release found pages. 600 * After releasing pages, hugetlb_unreserve_pages cleans up region/reserve 601 * maps and global counts. Page faults can race with truncation. 602 * During faults, hugetlb_no_page() checks i_size before page allocation, 603 * and again after obtaining page table lock. It will 'back out' 604 * allocations in the truncated range. 605 * hole punch is indicated if end is not LLONG_MAX 606 * In the hole punch case we scan the range and release found pages. 607 * Only when releasing a page is the associated region/reserve map 608 * deleted. The region/reserve map for ranges without associated 609 * pages are not modified. Page faults can race with hole punch. 610 * This is indicated if we find a mapped page. 611 * Note: If the passed end of range value is beyond the end of file, but 612 * not LLONG_MAX this routine still performs a hole punch operation. 613 */ 614 static void remove_inode_hugepages(struct inode *inode, loff_t lstart, 615 loff_t lend) 616 { 617 struct hstate *h = hstate_inode(inode); 618 struct address_space *mapping = &inode->i_data; 619 const pgoff_t start = lstart >> huge_page_shift(h); 620 const pgoff_t end = lend >> huge_page_shift(h); 621 struct folio_batch fbatch; 622 pgoff_t next, index; 623 int i, freed = 0; 624 bool truncate_op = (lend == LLONG_MAX); 625 626 folio_batch_init(&fbatch); 627 next = start; 628 while (filemap_get_folios(mapping, &next, end - 1, &fbatch)) { 629 for (i = 0; i < folio_batch_count(&fbatch); ++i) { 630 struct folio *folio = fbatch.folios[i]; 631 u32 hash = 0; 632 633 index = folio->index; 634 hash = hugetlb_fault_mutex_hash(mapping, index); 635 mutex_lock(&hugetlb_fault_mutex_table[hash]); 636 637 /* 638 * Remove folio that was part of folio_batch. 639 */ 640 if (remove_inode_single_folio(h, inode, mapping, folio, 641 index, truncate_op)) 642 freed++; 643 644 mutex_unlock(&hugetlb_fault_mutex_table[hash]); 645 } 646 folio_batch_release(&fbatch); 647 cond_resched(); 648 } 649 650 if (truncate_op) 651 (void)hugetlb_unreserve_pages(inode, start, LONG_MAX, freed); 652 } 653 654 static void hugetlbfs_evict_inode(struct inode *inode) 655 { 656 struct resv_map *resv_map; 657 658 remove_inode_hugepages(inode, 0, LLONG_MAX); 659 660 /* 661 * Get the resv_map from the address space embedded in the inode. 662 * This is the address space which points to any resv_map allocated 663 * at inode creation time. If this is a device special inode, 664 * i_mapping may not point to the original address space. 665 */ 666 resv_map = (struct resv_map *)(&inode->i_data)->private_data; 667 /* Only regular and link inodes have associated reserve maps */ 668 if (resv_map) 669 resv_map_release(&resv_map->refs); 670 clear_inode(inode); 671 } 672 673 static void hugetlb_vmtruncate(struct inode *inode, loff_t offset) 674 { 675 pgoff_t pgoff; 676 struct address_space *mapping = inode->i_mapping; 677 struct hstate *h = hstate_inode(inode); 678 679 BUG_ON(offset & ~huge_page_mask(h)); 680 pgoff = offset >> PAGE_SHIFT; 681 682 i_size_write(inode, offset); 683 i_mmap_lock_write(mapping); 684 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root)) 685 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0, 686 ZAP_FLAG_DROP_MARKER); 687 i_mmap_unlock_write(mapping); 688 remove_inode_hugepages(inode, offset, LLONG_MAX); 689 } 690 691 static void hugetlbfs_zero_partial_page(struct hstate *h, 692 struct address_space *mapping, 693 loff_t start, 694 loff_t end) 695 { 696 pgoff_t idx = start >> huge_page_shift(h); 697 struct folio *folio; 698 699 folio = filemap_lock_folio(mapping, idx); 700 if (IS_ERR(folio)) 701 return; 702 703 start = start & ~huge_page_mask(h); 704 end = end & ~huge_page_mask(h); 705 if (!end) 706 end = huge_page_size(h); 707 708 folio_zero_segment(folio, (size_t)start, (size_t)end); 709 710 folio_unlock(folio); 711 folio_put(folio); 712 } 713 714 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) 715 { 716 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode); 717 struct address_space *mapping = inode->i_mapping; 718 struct hstate *h = hstate_inode(inode); 719 loff_t hpage_size = huge_page_size(h); 720 loff_t hole_start, hole_end; 721 722 /* 723 * hole_start and hole_end indicate the full pages within the hole. 724 */ 725 hole_start = round_up(offset, hpage_size); 726 hole_end = round_down(offset + len, hpage_size); 727 728 inode_lock(inode); 729 730 /* protected by i_rwsem */ 731 if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) { 732 inode_unlock(inode); 733 return -EPERM; 734 } 735 736 i_mmap_lock_write(mapping); 737 738 /* If range starts before first full page, zero partial page. */ 739 if (offset < hole_start) 740 hugetlbfs_zero_partial_page(h, mapping, 741 offset, min(offset + len, hole_start)); 742 743 /* Unmap users of full pages in the hole. */ 744 if (hole_end > hole_start) { 745 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root)) 746 hugetlb_vmdelete_list(&mapping->i_mmap, 747 hole_start >> PAGE_SHIFT, 748 hole_end >> PAGE_SHIFT, 0); 749 } 750 751 /* If range extends beyond last full page, zero partial page. */ 752 if ((offset + len) > hole_end && (offset + len) > hole_start) 753 hugetlbfs_zero_partial_page(h, mapping, 754 hole_end, offset + len); 755 756 i_mmap_unlock_write(mapping); 757 758 /* Remove full pages from the file. */ 759 if (hole_end > hole_start) 760 remove_inode_hugepages(inode, hole_start, hole_end); 761 762 inode_unlock(inode); 763 764 return 0; 765 } 766 767 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset, 768 loff_t len) 769 { 770 struct inode *inode = file_inode(file); 771 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode); 772 struct address_space *mapping = inode->i_mapping; 773 struct hstate *h = hstate_inode(inode); 774 struct vm_area_struct pseudo_vma; 775 struct mm_struct *mm = current->mm; 776 loff_t hpage_size = huge_page_size(h); 777 unsigned long hpage_shift = huge_page_shift(h); 778 pgoff_t start, index, end; 779 int error; 780 u32 hash; 781 782 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) 783 return -EOPNOTSUPP; 784 785 if (mode & FALLOC_FL_PUNCH_HOLE) 786 return hugetlbfs_punch_hole(inode, offset, len); 787 788 /* 789 * Default preallocate case. 790 * For this range, start is rounded down and end is rounded up 791 * as well as being converted to page offsets. 792 */ 793 start = offset >> hpage_shift; 794 end = (offset + len + hpage_size - 1) >> hpage_shift; 795 796 inode_lock(inode); 797 798 /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */ 799 error = inode_newsize_ok(inode, offset + len); 800 if (error) 801 goto out; 802 803 if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) { 804 error = -EPERM; 805 goto out; 806 } 807 808 /* 809 * Initialize a pseudo vma as this is required by the huge page 810 * allocation routines. If NUMA is configured, use page index 811 * as input to create an allocation policy. 812 */ 813 vma_init(&pseudo_vma, mm); 814 vm_flags_init(&pseudo_vma, VM_HUGETLB | VM_MAYSHARE | VM_SHARED); 815 pseudo_vma.vm_file = file; 816 817 for (index = start; index < end; index++) { 818 /* 819 * This is supposed to be the vaddr where the page is being 820 * faulted in, but we have no vaddr here. 821 */ 822 struct folio *folio; 823 unsigned long addr; 824 bool present; 825 826 cond_resched(); 827 828 /* 829 * fallocate(2) manpage permits EINTR; we may have been 830 * interrupted because we are using up too much memory. 831 */ 832 if (signal_pending(current)) { 833 error = -EINTR; 834 break; 835 } 836 837 /* addr is the offset within the file (zero based) */ 838 addr = index * hpage_size; 839 840 /* mutex taken here, fault path and hole punch */ 841 hash = hugetlb_fault_mutex_hash(mapping, index); 842 mutex_lock(&hugetlb_fault_mutex_table[hash]); 843 844 /* See if already present in mapping to avoid alloc/free */ 845 rcu_read_lock(); 846 present = page_cache_next_miss(mapping, index, 1) != index; 847 rcu_read_unlock(); 848 if (present) { 849 mutex_unlock(&hugetlb_fault_mutex_table[hash]); 850 continue; 851 } 852 853 /* 854 * Allocate folio without setting the avoid_reserve argument. 855 * There certainly are no reserves associated with the 856 * pseudo_vma. However, there could be shared mappings with 857 * reserves for the file at the inode level. If we fallocate 858 * folios in these areas, we need to consume the reserves 859 * to keep reservation accounting consistent. 860 */ 861 hugetlb_set_vma_policy(&pseudo_vma, inode, index); 862 folio = alloc_hugetlb_folio(&pseudo_vma, addr, 0); 863 hugetlb_drop_vma_policy(&pseudo_vma); 864 if (IS_ERR(folio)) { 865 mutex_unlock(&hugetlb_fault_mutex_table[hash]); 866 error = PTR_ERR(folio); 867 goto out; 868 } 869 clear_huge_page(&folio->page, addr, pages_per_huge_page(h)); 870 __folio_mark_uptodate(folio); 871 error = hugetlb_add_to_page_cache(folio, mapping, index); 872 if (unlikely(error)) { 873 restore_reserve_on_error(h, &pseudo_vma, addr, folio); 874 folio_put(folio); 875 mutex_unlock(&hugetlb_fault_mutex_table[hash]); 876 goto out; 877 } 878 879 mutex_unlock(&hugetlb_fault_mutex_table[hash]); 880 881 folio_set_hugetlb_migratable(folio); 882 /* 883 * folio_unlock because locked by hugetlb_add_to_page_cache() 884 * folio_put() due to reference from alloc_hugetlb_folio() 885 */ 886 folio_unlock(folio); 887 folio_put(folio); 888 } 889 890 if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) 891 i_size_write(inode, offset + len); 892 inode->i_ctime = current_time(inode); 893 out: 894 inode_unlock(inode); 895 return error; 896 } 897 898 static int hugetlbfs_setattr(struct mnt_idmap *idmap, 899 struct dentry *dentry, struct iattr *attr) 900 { 901 struct inode *inode = d_inode(dentry); 902 struct hstate *h = hstate_inode(inode); 903 int error; 904 unsigned int ia_valid = attr->ia_valid; 905 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode); 906 907 error = setattr_prepare(&nop_mnt_idmap, dentry, attr); 908 if (error) 909 return error; 910 911 if (ia_valid & ATTR_SIZE) { 912 loff_t oldsize = inode->i_size; 913 loff_t newsize = attr->ia_size; 914 915 if (newsize & ~huge_page_mask(h)) 916 return -EINVAL; 917 /* protected by i_rwsem */ 918 if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) || 919 (newsize > oldsize && (info->seals & F_SEAL_GROW))) 920 return -EPERM; 921 hugetlb_vmtruncate(inode, newsize); 922 } 923 924 setattr_copy(&nop_mnt_idmap, inode, attr); 925 mark_inode_dirty(inode); 926 return 0; 927 } 928 929 static struct inode *hugetlbfs_get_root(struct super_block *sb, 930 struct hugetlbfs_fs_context *ctx) 931 { 932 struct inode *inode; 933 934 inode = new_inode(sb); 935 if (inode) { 936 inode->i_ino = get_next_ino(); 937 inode->i_mode = S_IFDIR | ctx->mode; 938 inode->i_uid = ctx->uid; 939 inode->i_gid = ctx->gid; 940 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); 941 inode->i_op = &hugetlbfs_dir_inode_operations; 942 inode->i_fop = &simple_dir_operations; 943 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 944 inc_nlink(inode); 945 lockdep_annotate_inode_mutex_key(inode); 946 } 947 return inode; 948 } 949 950 /* 951 * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never 952 * be taken from reclaim -- unlike regular filesystems. This needs an 953 * annotation because huge_pmd_share() does an allocation under hugetlb's 954 * i_mmap_rwsem. 955 */ 956 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key; 957 958 static struct inode *hugetlbfs_get_inode(struct super_block *sb, 959 struct inode *dir, 960 umode_t mode, dev_t dev) 961 { 962 struct inode *inode; 963 struct resv_map *resv_map = NULL; 964 965 /* 966 * Reserve maps are only needed for inodes that can have associated 967 * page allocations. 968 */ 969 if (S_ISREG(mode) || S_ISLNK(mode)) { 970 resv_map = resv_map_alloc(); 971 if (!resv_map) 972 return NULL; 973 } 974 975 inode = new_inode(sb); 976 if (inode) { 977 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode); 978 979 inode->i_ino = get_next_ino(); 980 inode_init_owner(&nop_mnt_idmap, inode, dir, mode); 981 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem, 982 &hugetlbfs_i_mmap_rwsem_key); 983 inode->i_mapping->a_ops = &hugetlbfs_aops; 984 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); 985 inode->i_mapping->private_data = resv_map; 986 info->seals = F_SEAL_SEAL; 987 switch (mode & S_IFMT) { 988 default: 989 init_special_inode(inode, mode, dev); 990 break; 991 case S_IFREG: 992 inode->i_op = &hugetlbfs_inode_operations; 993 inode->i_fop = &hugetlbfs_file_operations; 994 break; 995 case S_IFDIR: 996 inode->i_op = &hugetlbfs_dir_inode_operations; 997 inode->i_fop = &simple_dir_operations; 998 999 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 1000 inc_nlink(inode); 1001 break; 1002 case S_IFLNK: 1003 inode->i_op = &page_symlink_inode_operations; 1004 inode_nohighmem(inode); 1005 break; 1006 } 1007 lockdep_annotate_inode_mutex_key(inode); 1008 } else { 1009 if (resv_map) 1010 kref_put(&resv_map->refs, resv_map_release); 1011 } 1012 1013 return inode; 1014 } 1015 1016 /* 1017 * File creation. Allocate an inode, and we're done.. 1018 */ 1019 static int hugetlbfs_mknod(struct mnt_idmap *idmap, struct inode *dir, 1020 struct dentry *dentry, umode_t mode, dev_t dev) 1021 { 1022 struct inode *inode; 1023 1024 inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev); 1025 if (!inode) 1026 return -ENOSPC; 1027 dir->i_ctime = dir->i_mtime = current_time(dir); 1028 d_instantiate(dentry, inode); 1029 dget(dentry);/* Extra count - pin the dentry in core */ 1030 return 0; 1031 } 1032 1033 static int hugetlbfs_mkdir(struct mnt_idmap *idmap, struct inode *dir, 1034 struct dentry *dentry, umode_t mode) 1035 { 1036 int retval = hugetlbfs_mknod(&nop_mnt_idmap, dir, dentry, 1037 mode | S_IFDIR, 0); 1038 if (!retval) 1039 inc_nlink(dir); 1040 return retval; 1041 } 1042 1043 static int hugetlbfs_create(struct mnt_idmap *idmap, 1044 struct inode *dir, struct dentry *dentry, 1045 umode_t mode, bool excl) 1046 { 1047 return hugetlbfs_mknod(&nop_mnt_idmap, dir, dentry, mode | S_IFREG, 0); 1048 } 1049 1050 static int hugetlbfs_tmpfile(struct mnt_idmap *idmap, 1051 struct inode *dir, struct file *file, 1052 umode_t mode) 1053 { 1054 struct inode *inode; 1055 1056 inode = hugetlbfs_get_inode(dir->i_sb, dir, mode | S_IFREG, 0); 1057 if (!inode) 1058 return -ENOSPC; 1059 dir->i_ctime = dir->i_mtime = current_time(dir); 1060 d_tmpfile(file, inode); 1061 return finish_open_simple(file, 0); 1062 } 1063 1064 static int hugetlbfs_symlink(struct mnt_idmap *idmap, 1065 struct inode *dir, struct dentry *dentry, 1066 const char *symname) 1067 { 1068 struct inode *inode; 1069 int error = -ENOSPC; 1070 1071 inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0); 1072 if (inode) { 1073 int l = strlen(symname)+1; 1074 error = page_symlink(inode, symname, l); 1075 if (!error) { 1076 d_instantiate(dentry, inode); 1077 dget(dentry); 1078 } else 1079 iput(inode); 1080 } 1081 dir->i_ctime = dir->i_mtime = current_time(dir); 1082 1083 return error; 1084 } 1085 1086 #ifdef CONFIG_MIGRATION 1087 static int hugetlbfs_migrate_folio(struct address_space *mapping, 1088 struct folio *dst, struct folio *src, 1089 enum migrate_mode mode) 1090 { 1091 int rc; 1092 1093 rc = migrate_huge_page_move_mapping(mapping, dst, src); 1094 if (rc != MIGRATEPAGE_SUCCESS) 1095 return rc; 1096 1097 if (hugetlb_folio_subpool(src)) { 1098 hugetlb_set_folio_subpool(dst, 1099 hugetlb_folio_subpool(src)); 1100 hugetlb_set_folio_subpool(src, NULL); 1101 } 1102 1103 if (mode != MIGRATE_SYNC_NO_COPY) 1104 folio_migrate_copy(dst, src); 1105 else 1106 folio_migrate_flags(dst, src); 1107 1108 return MIGRATEPAGE_SUCCESS; 1109 } 1110 #else 1111 #define hugetlbfs_migrate_folio NULL 1112 #endif 1113 1114 static int hugetlbfs_error_remove_page(struct address_space *mapping, 1115 struct page *page) 1116 { 1117 return 0; 1118 } 1119 1120 /* 1121 * Display the mount options in /proc/mounts. 1122 */ 1123 static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root) 1124 { 1125 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(root->d_sb); 1126 struct hugepage_subpool *spool = sbinfo->spool; 1127 unsigned long hpage_size = huge_page_size(sbinfo->hstate); 1128 unsigned hpage_shift = huge_page_shift(sbinfo->hstate); 1129 char mod; 1130 1131 if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID)) 1132 seq_printf(m, ",uid=%u", 1133 from_kuid_munged(&init_user_ns, sbinfo->uid)); 1134 if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID)) 1135 seq_printf(m, ",gid=%u", 1136 from_kgid_munged(&init_user_ns, sbinfo->gid)); 1137 if (sbinfo->mode != 0755) 1138 seq_printf(m, ",mode=%o", sbinfo->mode); 1139 if (sbinfo->max_inodes != -1) 1140 seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes); 1141 1142 hpage_size /= 1024; 1143 mod = 'K'; 1144 if (hpage_size >= 1024) { 1145 hpage_size /= 1024; 1146 mod = 'M'; 1147 } 1148 seq_printf(m, ",pagesize=%lu%c", hpage_size, mod); 1149 if (spool) { 1150 if (spool->max_hpages != -1) 1151 seq_printf(m, ",size=%llu", 1152 (unsigned long long)spool->max_hpages << hpage_shift); 1153 if (spool->min_hpages != -1) 1154 seq_printf(m, ",min_size=%llu", 1155 (unsigned long long)spool->min_hpages << hpage_shift); 1156 } 1157 return 0; 1158 } 1159 1160 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf) 1161 { 1162 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb); 1163 struct hstate *h = hstate_inode(d_inode(dentry)); 1164 1165 buf->f_type = HUGETLBFS_MAGIC; 1166 buf->f_bsize = huge_page_size(h); 1167 if (sbinfo) { 1168 spin_lock(&sbinfo->stat_lock); 1169 /* If no limits set, just report 0 or -1 for max/free/used 1170 * blocks, like simple_statfs() */ 1171 if (sbinfo->spool) { 1172 long free_pages; 1173 1174 spin_lock_irq(&sbinfo->spool->lock); 1175 buf->f_blocks = sbinfo->spool->max_hpages; 1176 free_pages = sbinfo->spool->max_hpages 1177 - sbinfo->spool->used_hpages; 1178 buf->f_bavail = buf->f_bfree = free_pages; 1179 spin_unlock_irq(&sbinfo->spool->lock); 1180 buf->f_files = sbinfo->max_inodes; 1181 buf->f_ffree = sbinfo->free_inodes; 1182 } 1183 spin_unlock(&sbinfo->stat_lock); 1184 } 1185 buf->f_namelen = NAME_MAX; 1186 return 0; 1187 } 1188 1189 static void hugetlbfs_put_super(struct super_block *sb) 1190 { 1191 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb); 1192 1193 if (sbi) { 1194 sb->s_fs_info = NULL; 1195 1196 if (sbi->spool) 1197 hugepage_put_subpool(sbi->spool); 1198 1199 kfree(sbi); 1200 } 1201 } 1202 1203 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo) 1204 { 1205 if (sbinfo->free_inodes >= 0) { 1206 spin_lock(&sbinfo->stat_lock); 1207 if (unlikely(!sbinfo->free_inodes)) { 1208 spin_unlock(&sbinfo->stat_lock); 1209 return 0; 1210 } 1211 sbinfo->free_inodes--; 1212 spin_unlock(&sbinfo->stat_lock); 1213 } 1214 1215 return 1; 1216 } 1217 1218 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo) 1219 { 1220 if (sbinfo->free_inodes >= 0) { 1221 spin_lock(&sbinfo->stat_lock); 1222 sbinfo->free_inodes++; 1223 spin_unlock(&sbinfo->stat_lock); 1224 } 1225 } 1226 1227 1228 static struct kmem_cache *hugetlbfs_inode_cachep; 1229 1230 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb) 1231 { 1232 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb); 1233 struct hugetlbfs_inode_info *p; 1234 1235 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo))) 1236 return NULL; 1237 p = alloc_inode_sb(sb, hugetlbfs_inode_cachep, GFP_KERNEL); 1238 if (unlikely(!p)) { 1239 hugetlbfs_inc_free_inodes(sbinfo); 1240 return NULL; 1241 } 1242 1243 /* 1244 * Any time after allocation, hugetlbfs_destroy_inode can be called 1245 * for the inode. mpol_free_shared_policy is unconditionally called 1246 * as part of hugetlbfs_destroy_inode. So, initialize policy here 1247 * in case of a quick call to destroy. 1248 * 1249 * Note that the policy is initialized even if we are creating a 1250 * private inode. This simplifies hugetlbfs_destroy_inode. 1251 */ 1252 mpol_shared_policy_init(&p->policy, NULL); 1253 1254 return &p->vfs_inode; 1255 } 1256 1257 static void hugetlbfs_free_inode(struct inode *inode) 1258 { 1259 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode)); 1260 } 1261 1262 static void hugetlbfs_destroy_inode(struct inode *inode) 1263 { 1264 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb)); 1265 mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy); 1266 } 1267 1268 static const struct address_space_operations hugetlbfs_aops = { 1269 .write_begin = hugetlbfs_write_begin, 1270 .write_end = hugetlbfs_write_end, 1271 .dirty_folio = noop_dirty_folio, 1272 .migrate_folio = hugetlbfs_migrate_folio, 1273 .error_remove_page = hugetlbfs_error_remove_page, 1274 }; 1275 1276 1277 static void init_once(void *foo) 1278 { 1279 struct hugetlbfs_inode_info *ei = foo; 1280 1281 inode_init_once(&ei->vfs_inode); 1282 } 1283 1284 const struct file_operations hugetlbfs_file_operations = { 1285 .read_iter = hugetlbfs_read_iter, 1286 .mmap = hugetlbfs_file_mmap, 1287 .fsync = noop_fsync, 1288 .get_unmapped_area = hugetlb_get_unmapped_area, 1289 .llseek = default_llseek, 1290 .fallocate = hugetlbfs_fallocate, 1291 }; 1292 1293 static const struct inode_operations hugetlbfs_dir_inode_operations = { 1294 .create = hugetlbfs_create, 1295 .lookup = simple_lookup, 1296 .link = simple_link, 1297 .unlink = simple_unlink, 1298 .symlink = hugetlbfs_symlink, 1299 .mkdir = hugetlbfs_mkdir, 1300 .rmdir = simple_rmdir, 1301 .mknod = hugetlbfs_mknod, 1302 .rename = simple_rename, 1303 .setattr = hugetlbfs_setattr, 1304 .tmpfile = hugetlbfs_tmpfile, 1305 }; 1306 1307 static const struct inode_operations hugetlbfs_inode_operations = { 1308 .setattr = hugetlbfs_setattr, 1309 }; 1310 1311 static const struct super_operations hugetlbfs_ops = { 1312 .alloc_inode = hugetlbfs_alloc_inode, 1313 .free_inode = hugetlbfs_free_inode, 1314 .destroy_inode = hugetlbfs_destroy_inode, 1315 .evict_inode = hugetlbfs_evict_inode, 1316 .statfs = hugetlbfs_statfs, 1317 .put_super = hugetlbfs_put_super, 1318 .show_options = hugetlbfs_show_options, 1319 }; 1320 1321 /* 1322 * Convert size option passed from command line to number of huge pages 1323 * in the pool specified by hstate. Size option could be in bytes 1324 * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT). 1325 */ 1326 static long 1327 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt, 1328 enum hugetlbfs_size_type val_type) 1329 { 1330 if (val_type == NO_SIZE) 1331 return -1; 1332 1333 if (val_type == SIZE_PERCENT) { 1334 size_opt <<= huge_page_shift(h); 1335 size_opt *= h->max_huge_pages; 1336 do_div(size_opt, 100); 1337 } 1338 1339 size_opt >>= huge_page_shift(h); 1340 return size_opt; 1341 } 1342 1343 /* 1344 * Parse one mount parameter. 1345 */ 1346 static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *param) 1347 { 1348 struct hugetlbfs_fs_context *ctx = fc->fs_private; 1349 struct fs_parse_result result; 1350 char *rest; 1351 unsigned long ps; 1352 int opt; 1353 1354 opt = fs_parse(fc, hugetlb_fs_parameters, param, &result); 1355 if (opt < 0) 1356 return opt; 1357 1358 switch (opt) { 1359 case Opt_uid: 1360 ctx->uid = make_kuid(current_user_ns(), result.uint_32); 1361 if (!uid_valid(ctx->uid)) 1362 goto bad_val; 1363 return 0; 1364 1365 case Opt_gid: 1366 ctx->gid = make_kgid(current_user_ns(), result.uint_32); 1367 if (!gid_valid(ctx->gid)) 1368 goto bad_val; 1369 return 0; 1370 1371 case Opt_mode: 1372 ctx->mode = result.uint_32 & 01777U; 1373 return 0; 1374 1375 case Opt_size: 1376 /* memparse() will accept a K/M/G without a digit */ 1377 if (!param->string || !isdigit(param->string[0])) 1378 goto bad_val; 1379 ctx->max_size_opt = memparse(param->string, &rest); 1380 ctx->max_val_type = SIZE_STD; 1381 if (*rest == '%') 1382 ctx->max_val_type = SIZE_PERCENT; 1383 return 0; 1384 1385 case Opt_nr_inodes: 1386 /* memparse() will accept a K/M/G without a digit */ 1387 if (!param->string || !isdigit(param->string[0])) 1388 goto bad_val; 1389 ctx->nr_inodes = memparse(param->string, &rest); 1390 return 0; 1391 1392 case Opt_pagesize: 1393 ps = memparse(param->string, &rest); 1394 ctx->hstate = size_to_hstate(ps); 1395 if (!ctx->hstate) { 1396 pr_err("Unsupported page size %lu MB\n", ps / SZ_1M); 1397 return -EINVAL; 1398 } 1399 return 0; 1400 1401 case Opt_min_size: 1402 /* memparse() will accept a K/M/G without a digit */ 1403 if (!param->string || !isdigit(param->string[0])) 1404 goto bad_val; 1405 ctx->min_size_opt = memparse(param->string, &rest); 1406 ctx->min_val_type = SIZE_STD; 1407 if (*rest == '%') 1408 ctx->min_val_type = SIZE_PERCENT; 1409 return 0; 1410 1411 default: 1412 return -EINVAL; 1413 } 1414 1415 bad_val: 1416 return invalfc(fc, "Bad value '%s' for mount option '%s'\n", 1417 param->string, param->key); 1418 } 1419 1420 /* 1421 * Validate the parsed options. 1422 */ 1423 static int hugetlbfs_validate(struct fs_context *fc) 1424 { 1425 struct hugetlbfs_fs_context *ctx = fc->fs_private; 1426 1427 /* 1428 * Use huge page pool size (in hstate) to convert the size 1429 * options to number of huge pages. If NO_SIZE, -1 is returned. 1430 */ 1431 ctx->max_hpages = hugetlbfs_size_to_hpages(ctx->hstate, 1432 ctx->max_size_opt, 1433 ctx->max_val_type); 1434 ctx->min_hpages = hugetlbfs_size_to_hpages(ctx->hstate, 1435 ctx->min_size_opt, 1436 ctx->min_val_type); 1437 1438 /* 1439 * If max_size was specified, then min_size must be smaller 1440 */ 1441 if (ctx->max_val_type > NO_SIZE && 1442 ctx->min_hpages > ctx->max_hpages) { 1443 pr_err("Minimum size can not be greater than maximum size\n"); 1444 return -EINVAL; 1445 } 1446 1447 return 0; 1448 } 1449 1450 static int 1451 hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc) 1452 { 1453 struct hugetlbfs_fs_context *ctx = fc->fs_private; 1454 struct hugetlbfs_sb_info *sbinfo; 1455 1456 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL); 1457 if (!sbinfo) 1458 return -ENOMEM; 1459 sb->s_fs_info = sbinfo; 1460 spin_lock_init(&sbinfo->stat_lock); 1461 sbinfo->hstate = ctx->hstate; 1462 sbinfo->max_inodes = ctx->nr_inodes; 1463 sbinfo->free_inodes = ctx->nr_inodes; 1464 sbinfo->spool = NULL; 1465 sbinfo->uid = ctx->uid; 1466 sbinfo->gid = ctx->gid; 1467 sbinfo->mode = ctx->mode; 1468 1469 /* 1470 * Allocate and initialize subpool if maximum or minimum size is 1471 * specified. Any needed reservations (for minimum size) are taken 1472 * when the subpool is created. 1473 */ 1474 if (ctx->max_hpages != -1 || ctx->min_hpages != -1) { 1475 sbinfo->spool = hugepage_new_subpool(ctx->hstate, 1476 ctx->max_hpages, 1477 ctx->min_hpages); 1478 if (!sbinfo->spool) 1479 goto out_free; 1480 } 1481 sb->s_maxbytes = MAX_LFS_FILESIZE; 1482 sb->s_blocksize = huge_page_size(ctx->hstate); 1483 sb->s_blocksize_bits = huge_page_shift(ctx->hstate); 1484 sb->s_magic = HUGETLBFS_MAGIC; 1485 sb->s_op = &hugetlbfs_ops; 1486 sb->s_time_gran = 1; 1487 1488 /* 1489 * Due to the special and limited functionality of hugetlbfs, it does 1490 * not work well as a stacking filesystem. 1491 */ 1492 sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH; 1493 sb->s_root = d_make_root(hugetlbfs_get_root(sb, ctx)); 1494 if (!sb->s_root) 1495 goto out_free; 1496 return 0; 1497 out_free: 1498 kfree(sbinfo->spool); 1499 kfree(sbinfo); 1500 return -ENOMEM; 1501 } 1502 1503 static int hugetlbfs_get_tree(struct fs_context *fc) 1504 { 1505 int err = hugetlbfs_validate(fc); 1506 if (err) 1507 return err; 1508 return get_tree_nodev(fc, hugetlbfs_fill_super); 1509 } 1510 1511 static void hugetlbfs_fs_context_free(struct fs_context *fc) 1512 { 1513 kfree(fc->fs_private); 1514 } 1515 1516 static const struct fs_context_operations hugetlbfs_fs_context_ops = { 1517 .free = hugetlbfs_fs_context_free, 1518 .parse_param = hugetlbfs_parse_param, 1519 .get_tree = hugetlbfs_get_tree, 1520 }; 1521 1522 static int hugetlbfs_init_fs_context(struct fs_context *fc) 1523 { 1524 struct hugetlbfs_fs_context *ctx; 1525 1526 ctx = kzalloc(sizeof(struct hugetlbfs_fs_context), GFP_KERNEL); 1527 if (!ctx) 1528 return -ENOMEM; 1529 1530 ctx->max_hpages = -1; /* No limit on size by default */ 1531 ctx->nr_inodes = -1; /* No limit on number of inodes by default */ 1532 ctx->uid = current_fsuid(); 1533 ctx->gid = current_fsgid(); 1534 ctx->mode = 0755; 1535 ctx->hstate = &default_hstate; 1536 ctx->min_hpages = -1; /* No default minimum size */ 1537 ctx->max_val_type = NO_SIZE; 1538 ctx->min_val_type = NO_SIZE; 1539 fc->fs_private = ctx; 1540 fc->ops = &hugetlbfs_fs_context_ops; 1541 return 0; 1542 } 1543 1544 static struct file_system_type hugetlbfs_fs_type = { 1545 .name = "hugetlbfs", 1546 .init_fs_context = hugetlbfs_init_fs_context, 1547 .parameters = hugetlb_fs_parameters, 1548 .kill_sb = kill_litter_super, 1549 }; 1550 1551 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE]; 1552 1553 static int can_do_hugetlb_shm(void) 1554 { 1555 kgid_t shm_group; 1556 shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group); 1557 return capable(CAP_IPC_LOCK) || in_group_p(shm_group); 1558 } 1559 1560 static int get_hstate_idx(int page_size_log) 1561 { 1562 struct hstate *h = hstate_sizelog(page_size_log); 1563 1564 if (!h) 1565 return -1; 1566 return hstate_index(h); 1567 } 1568 1569 /* 1570 * Note that size should be aligned to proper hugepage size in caller side, 1571 * otherwise hugetlb_reserve_pages reserves one less hugepages than intended. 1572 */ 1573 struct file *hugetlb_file_setup(const char *name, size_t size, 1574 vm_flags_t acctflag, int creat_flags, 1575 int page_size_log) 1576 { 1577 struct inode *inode; 1578 struct vfsmount *mnt; 1579 int hstate_idx; 1580 struct file *file; 1581 1582 hstate_idx = get_hstate_idx(page_size_log); 1583 if (hstate_idx < 0) 1584 return ERR_PTR(-ENODEV); 1585 1586 mnt = hugetlbfs_vfsmount[hstate_idx]; 1587 if (!mnt) 1588 return ERR_PTR(-ENOENT); 1589 1590 if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) { 1591 struct ucounts *ucounts = current_ucounts(); 1592 1593 if (user_shm_lock(size, ucounts)) { 1594 pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is obsolete\n", 1595 current->comm, current->pid); 1596 user_shm_unlock(size, ucounts); 1597 } 1598 return ERR_PTR(-EPERM); 1599 } 1600 1601 file = ERR_PTR(-ENOSPC); 1602 inode = hugetlbfs_get_inode(mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0); 1603 if (!inode) 1604 goto out; 1605 if (creat_flags == HUGETLB_SHMFS_INODE) 1606 inode->i_flags |= S_PRIVATE; 1607 1608 inode->i_size = size; 1609 clear_nlink(inode); 1610 1611 if (!hugetlb_reserve_pages(inode, 0, 1612 size >> huge_page_shift(hstate_inode(inode)), NULL, 1613 acctflag)) 1614 file = ERR_PTR(-ENOMEM); 1615 else 1616 file = alloc_file_pseudo(inode, mnt, name, O_RDWR, 1617 &hugetlbfs_file_operations); 1618 if (!IS_ERR(file)) 1619 return file; 1620 1621 iput(inode); 1622 out: 1623 return file; 1624 } 1625 1626 static struct vfsmount *__init mount_one_hugetlbfs(struct hstate *h) 1627 { 1628 struct fs_context *fc; 1629 struct vfsmount *mnt; 1630 1631 fc = fs_context_for_mount(&hugetlbfs_fs_type, SB_KERNMOUNT); 1632 if (IS_ERR(fc)) { 1633 mnt = ERR_CAST(fc); 1634 } else { 1635 struct hugetlbfs_fs_context *ctx = fc->fs_private; 1636 ctx->hstate = h; 1637 mnt = fc_mount(fc); 1638 put_fs_context(fc); 1639 } 1640 if (IS_ERR(mnt)) 1641 pr_err("Cannot mount internal hugetlbfs for page size %luK", 1642 huge_page_size(h) / SZ_1K); 1643 return mnt; 1644 } 1645 1646 static int __init init_hugetlbfs_fs(void) 1647 { 1648 struct vfsmount *mnt; 1649 struct hstate *h; 1650 int error; 1651 int i; 1652 1653 if (!hugepages_supported()) { 1654 pr_info("disabling because there are no supported hugepage sizes\n"); 1655 return -ENOTSUPP; 1656 } 1657 1658 error = -ENOMEM; 1659 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache", 1660 sizeof(struct hugetlbfs_inode_info), 1661 0, SLAB_ACCOUNT, init_once); 1662 if (hugetlbfs_inode_cachep == NULL) 1663 goto out; 1664 1665 error = register_filesystem(&hugetlbfs_fs_type); 1666 if (error) 1667 goto out_free; 1668 1669 /* default hstate mount is required */ 1670 mnt = mount_one_hugetlbfs(&default_hstate); 1671 if (IS_ERR(mnt)) { 1672 error = PTR_ERR(mnt); 1673 goto out_unreg; 1674 } 1675 hugetlbfs_vfsmount[default_hstate_idx] = mnt; 1676 1677 /* other hstates are optional */ 1678 i = 0; 1679 for_each_hstate(h) { 1680 if (i == default_hstate_idx) { 1681 i++; 1682 continue; 1683 } 1684 1685 mnt = mount_one_hugetlbfs(h); 1686 if (IS_ERR(mnt)) 1687 hugetlbfs_vfsmount[i] = NULL; 1688 else 1689 hugetlbfs_vfsmount[i] = mnt; 1690 i++; 1691 } 1692 1693 return 0; 1694 1695 out_unreg: 1696 (void)unregister_filesystem(&hugetlbfs_fs_type); 1697 out_free: 1698 kmem_cache_destroy(hugetlbfs_inode_cachep); 1699 out: 1700 return error; 1701 } 1702 fs_initcall(init_hugetlbfs_fs) 1703