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 42static const struct address_space_operations hugetlbfs_aops; 43const struct file_operations hugetlbfs_file_operations; 44static const struct inode_operations hugetlbfs_dir_inode_operations; 45static const struct inode_operations hugetlbfs_inode_operations; 46 47enum hugetlbfs_size_type { NO_SIZE, SIZE_STD, SIZE_PERCENT }; 48 49struct 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 63int sysctl_hugetlb_shm_group; 64 65enum 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 75static 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/* 87 * Mask used when checking the page offset value passed in via system 88 * calls. This value will be converted to a loff_t which is signed. 89 * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the 90 * value. The extra bit (- 1 in the shift value) is to take the sign 91 * bit into account. 92 */ 93#define PGOFF_LOFFT_MAX \ 94 (((1UL << (PAGE_SHIFT + 1)) - 1) << (BITS_PER_LONG - (PAGE_SHIFT + 1))) 95 96static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma) 97{ 98 struct inode *inode = file_inode(file); 99 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode); 100 loff_t len, vma_len; 101 int ret; 102 struct hstate *h = hstate_file(file); 103 vm_flags_t vm_flags; 104 105 /* 106 * vma address alignment (but not the pgoff alignment) has 107 * already been checked by prepare_hugepage_range. If you add 108 * any error returns here, do so after setting VM_HUGETLB, so 109 * is_vm_hugetlb_page tests below unmap_region go the right 110 * way when do_mmap unwinds (may be important on powerpc 111 * and ia64). 112 */ 113 vm_flags_set(vma, VM_HUGETLB | VM_DONTEXPAND); 114 vma->vm_ops = &hugetlb_vm_ops; 115 116 ret = seal_check_write(info->seals, vma); 117 if (ret) 118 return ret; 119 120 /* 121 * page based offset in vm_pgoff could be sufficiently large to 122 * overflow a loff_t when converted to byte offset. This can 123 * only happen on architectures where sizeof(loff_t) == 124 * sizeof(unsigned long). So, only check in those instances. 125 */ 126 if (sizeof(unsigned long) == sizeof(loff_t)) { 127 if (vma->vm_pgoff & PGOFF_LOFFT_MAX) 128 return -EINVAL; 129 } 130 131 /* must be huge page aligned */ 132 if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT)) 133 return -EINVAL; 134 135 vma_len = (loff_t)(vma->vm_end - vma->vm_start); 136 len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); 137 /* check for overflow */ 138 if (len < vma_len) 139 return -EINVAL; 140 141 inode_lock(inode); 142 file_accessed(file); 143 144 ret = -ENOMEM; 145 146 vm_flags = vma->vm_flags; 147 /* 148 * for SHM_HUGETLB, the pages are reserved in the shmget() call so skip 149 * reserving here. Note: only for SHM hugetlbfs file, the inode 150 * flag S_PRIVATE is set. 151 */ 152 if (inode->i_flags & S_PRIVATE) 153 vm_flags |= VM_NORESERVE; 154 155 if (!hugetlb_reserve_pages(inode, 156 vma->vm_pgoff >> huge_page_order(h), 157 len >> huge_page_shift(h), vma, 158 vm_flags)) 159 goto out; 160 161 ret = 0; 162 if (vma->vm_flags & VM_WRITE && inode->i_size < len) 163 i_size_write(inode, len); 164out: 165 inode_unlock(inode); 166 167 return ret; 168} 169 170/* 171 * Called under mmap_write_lock(mm). 172 */ 173 174static unsigned long 175hugetlb_get_unmapped_area_bottomup(struct file *file, unsigned long addr, 176 unsigned long len, unsigned long pgoff, unsigned long flags) 177{ 178 struct hstate *h = hstate_file(file); 179 struct vm_unmapped_area_info info; 180 181 info.flags = 0; 182 info.length = len; 183 info.low_limit = current->mm->mmap_base; 184 info.high_limit = arch_get_mmap_end(addr, len, flags); 185 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 186 info.align_offset = 0; 187 return vm_unmapped_area(&info); 188} 189 190static unsigned long 191hugetlb_get_unmapped_area_topdown(struct file *file, unsigned long addr, 192 unsigned long len, unsigned long pgoff, unsigned long flags) 193{ 194 struct hstate *h = hstate_file(file); 195 struct vm_unmapped_area_info info; 196 197 info.flags = VM_UNMAPPED_AREA_TOPDOWN; 198 info.length = len; 199 info.low_limit = PAGE_SIZE; 200 info.high_limit = arch_get_mmap_base(addr, current->mm->mmap_base); 201 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 202 info.align_offset = 0; 203 addr = vm_unmapped_area(&info); 204 205 /* 206 * A failed mmap() very likely causes application failure, 207 * so fall back to the bottom-up function here. This scenario 208 * can happen with large stack limits and large mmap() 209 * allocations. 210 */ 211 if (unlikely(offset_in_page(addr))) { 212 VM_BUG_ON(addr != -ENOMEM); 213 info.flags = 0; 214 info.low_limit = current->mm->mmap_base; 215 info.high_limit = arch_get_mmap_end(addr, len, flags); 216 addr = vm_unmapped_area(&info); 217 } 218 219 return addr; 220} 221 222unsigned long 223generic_hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 224 unsigned long len, unsigned long pgoff, 225 unsigned long flags) 226{ 227 struct mm_struct *mm = current->mm; 228 struct vm_area_struct *vma; 229 struct hstate *h = hstate_file(file); 230 const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); 231 232 if (len & ~huge_page_mask(h)) 233 return -EINVAL; 234 if (len > TASK_SIZE) 235 return -ENOMEM; 236 237 if (flags & MAP_FIXED) { 238 if (prepare_hugepage_range(file, addr, len)) 239 return -EINVAL; 240 return addr; 241 } 242 243 if (addr) { 244 addr = ALIGN(addr, huge_page_size(h)); 245 vma = find_vma(mm, addr); 246 if (mmap_end - len >= addr && 247 (!vma || addr + len <= vm_start_gap(vma))) 248 return addr; 249 } 250 251 /* 252 * Use mm->get_unmapped_area value as a hint to use topdown routine. 253 * If architectures have special needs, they should define their own 254 * version of hugetlb_get_unmapped_area. 255 */ 256 if (mm->get_unmapped_area == arch_get_unmapped_area_topdown) 257 return hugetlb_get_unmapped_area_topdown(file, addr, len, 258 pgoff, flags); 259 return hugetlb_get_unmapped_area_bottomup(file, addr, len, 260 pgoff, flags); 261} 262 263#ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA 264static unsigned long 265hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 266 unsigned long len, unsigned long pgoff, 267 unsigned long flags) 268{ 269 return generic_hugetlb_get_unmapped_area(file, addr, len, pgoff, flags); 270} 271#endif 272 273/* 274 * Someone wants to read @bytes from a HWPOISON hugetlb @page from @offset. 275 * Returns the maximum number of bytes one can read without touching the 1st raw 276 * HWPOISON subpage. 277 * 278 * The implementation borrows the iteration logic from copy_page_to_iter*. 279 */ 280static size_t adjust_range_hwpoison(struct page *page, size_t offset, size_t bytes) 281{ 282 size_t n = 0; 283 size_t res = 0; 284 285 /* First subpage to start the loop. */ 286 page = nth_page(page, offset / PAGE_SIZE); 287 offset %= PAGE_SIZE; 288 while (1) { 289 if (is_raw_hwpoison_page_in_hugepage(page)) 290 break; 291 292 /* Safe to read n bytes without touching HWPOISON subpage. */ 293 n = min(bytes, (size_t)PAGE_SIZE - offset); 294 res += n; 295 bytes -= n; 296 if (!bytes || !n) 297 break; 298 offset += n; 299 if (offset == PAGE_SIZE) { 300 page = nth_page(page, 1); 301 offset = 0; 302 } 303 } 304 305 return res; 306} 307 308/* 309 * Support for read() - Find the page attached to f_mapping and copy out the 310 * data. This provides functionality similar to filemap_read(). 311 */ 312static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to) 313{ 314 struct file *file = iocb->ki_filp; 315 struct hstate *h = hstate_file(file); 316 struct address_space *mapping = file->f_mapping; 317 struct inode *inode = mapping->host; 318 unsigned long index = iocb->ki_pos >> huge_page_shift(h); 319 unsigned long offset = iocb->ki_pos & ~huge_page_mask(h); 320 unsigned long end_index; 321 loff_t isize; 322 ssize_t retval = 0; 323 324 while (iov_iter_count(to)) { 325 struct folio *folio; 326 size_t nr, copied, want; 327 328 /* nr is the maximum number of bytes to copy from this page */ 329 nr = huge_page_size(h); 330 isize = i_size_read(inode); 331 if (!isize) 332 break; 333 end_index = (isize - 1) >> huge_page_shift(h); 334 if (index > end_index) 335 break; 336 if (index == end_index) { 337 nr = ((isize - 1) & ~huge_page_mask(h)) + 1; 338 if (nr <= offset) 339 break; 340 } 341 nr = nr - offset; 342 343 /* Find the folio */ 344 folio = filemap_lock_hugetlb_folio(h, mapping, index); 345 if (IS_ERR(folio)) { 346 /* 347 * We have a HOLE, zero out the user-buffer for the 348 * length of the hole or request. 349 */ 350 copied = iov_iter_zero(nr, to); 351 } else { 352 folio_unlock(folio); 353 354 if (!folio_test_hwpoison(folio)) 355 want = nr; 356 else { 357 /* 358 * Adjust how many bytes safe to read without 359 * touching the 1st raw HWPOISON subpage after 360 * offset. 361 */ 362 want = adjust_range_hwpoison(&folio->page, offset, nr); 363 if (want == 0) { 364 folio_put(folio); 365 retval = -EIO; 366 break; 367 } 368 } 369 370 /* 371 * We have the folio, copy it to user space buffer. 372 */ 373 copied = copy_folio_to_iter(folio, offset, want, to); 374 folio_put(folio); 375 } 376 offset += copied; 377 retval += copied; 378 if (copied != nr && iov_iter_count(to)) { 379 if (!retval) 380 retval = -EFAULT; 381 break; 382 } 383 index += offset >> huge_page_shift(h); 384 offset &= ~huge_page_mask(h); 385 } 386 iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset; 387 return retval; 388} 389 390static int hugetlbfs_write_begin(struct file *file, 391 struct address_space *mapping, 392 loff_t pos, unsigned len, 393 struct page **pagep, void **fsdata) 394{ 395 return -EINVAL; 396} 397 398static int hugetlbfs_write_end(struct file *file, struct address_space *mapping, 399 loff_t pos, unsigned len, unsigned copied, 400 struct page *page, void *fsdata) 401{ 402 BUG(); 403 return -EINVAL; 404} 405 406static void hugetlb_delete_from_page_cache(struct folio *folio) 407{ 408 folio_clear_dirty(folio); 409 folio_clear_uptodate(folio); 410 filemap_remove_folio(folio); 411} 412 413/* 414 * Called with i_mmap_rwsem held for inode based vma maps. This makes 415 * sure vma (and vm_mm) will not go away. We also hold the hugetlb fault 416 * mutex for the page in the mapping. So, we can not race with page being 417 * faulted into the vma. 418 */ 419static bool hugetlb_vma_maps_page(struct vm_area_struct *vma, 420 unsigned long addr, struct page *page) 421{ 422 pte_t *ptep, pte; 423 424 ptep = hugetlb_walk(vma, addr, huge_page_size(hstate_vma(vma))); 425 if (!ptep) 426 return false; 427 428 pte = huge_ptep_get(ptep); 429 if (huge_pte_none(pte) || !pte_present(pte)) 430 return false; 431 432 if (pte_page(pte) == page) 433 return true; 434 435 return false; 436} 437 438/* 439 * Can vma_offset_start/vma_offset_end overflow on 32-bit arches? 440 * No, because the interval tree returns us only those vmas 441 * which overlap the truncated area starting at pgoff, 442 * and no vma on a 32-bit arch can span beyond the 4GB. 443 */ 444static unsigned long vma_offset_start(struct vm_area_struct *vma, pgoff_t start) 445{ 446 unsigned long offset = 0; 447 448 if (vma->vm_pgoff < start) 449 offset = (start - vma->vm_pgoff) << PAGE_SHIFT; 450 451 return vma->vm_start + offset; 452} 453 454static unsigned long vma_offset_end(struct vm_area_struct *vma, pgoff_t end) 455{ 456 unsigned long t_end; 457 458 if (!end) 459 return vma->vm_end; 460 461 t_end = ((end - vma->vm_pgoff) << PAGE_SHIFT) + vma->vm_start; 462 if (t_end > vma->vm_end) 463 t_end = vma->vm_end; 464 return t_end; 465} 466 467/* 468 * Called with hugetlb fault mutex held. Therefore, no more mappings to 469 * this folio can be created while executing the routine. 470 */ 471static void hugetlb_unmap_file_folio(struct hstate *h, 472 struct address_space *mapping, 473 struct folio *folio, pgoff_t index) 474{ 475 struct rb_root_cached *root = &mapping->i_mmap; 476 struct hugetlb_vma_lock *vma_lock; 477 struct page *page = &folio->page; 478 struct vm_area_struct *vma; 479 unsigned long v_start; 480 unsigned long v_end; 481 pgoff_t start, end; 482 483 start = index * pages_per_huge_page(h); 484 end = (index + 1) * pages_per_huge_page(h); 485 486 i_mmap_lock_write(mapping); 487retry: 488 vma_lock = NULL; 489 vma_interval_tree_foreach(vma, root, start, end - 1) { 490 v_start = vma_offset_start(vma, start); 491 v_end = vma_offset_end(vma, end); 492 493 if (!hugetlb_vma_maps_page(vma, v_start, page)) 494 continue; 495 496 if (!hugetlb_vma_trylock_write(vma)) { 497 vma_lock = vma->vm_private_data; 498 /* 499 * If we can not get vma lock, we need to drop 500 * immap_sema and take locks in order. First, 501 * take a ref on the vma_lock structure so that 502 * we can be guaranteed it will not go away when 503 * dropping immap_sema. 504 */ 505 kref_get(&vma_lock->refs); 506 break; 507 } 508 509 unmap_hugepage_range(vma, v_start, v_end, NULL, 510 ZAP_FLAG_DROP_MARKER); 511 hugetlb_vma_unlock_write(vma); 512 } 513 514 i_mmap_unlock_write(mapping); 515 516 if (vma_lock) { 517 /* 518 * Wait on vma_lock. We know it is still valid as we have 519 * a reference. We must 'open code' vma locking as we do 520 * not know if vma_lock is still attached to vma. 521 */ 522 down_write(&vma_lock->rw_sema); 523 i_mmap_lock_write(mapping); 524 525 vma = vma_lock->vma; 526 if (!vma) { 527 /* 528 * If lock is no longer attached to vma, then just 529 * unlock, drop our reference and retry looking for 530 * other vmas. 531 */ 532 up_write(&vma_lock->rw_sema); 533 kref_put(&vma_lock->refs, hugetlb_vma_lock_release); 534 goto retry; 535 } 536 537 /* 538 * vma_lock is still attached to vma. Check to see if vma 539 * still maps page and if so, unmap. 540 */ 541 v_start = vma_offset_start(vma, start); 542 v_end = vma_offset_end(vma, end); 543 if (hugetlb_vma_maps_page(vma, v_start, page)) 544 unmap_hugepage_range(vma, v_start, v_end, NULL, 545 ZAP_FLAG_DROP_MARKER); 546 547 kref_put(&vma_lock->refs, hugetlb_vma_lock_release); 548 hugetlb_vma_unlock_write(vma); 549 550 goto retry; 551 } 552} 553 554static void 555hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end, 556 zap_flags_t zap_flags) 557{ 558 struct vm_area_struct *vma; 559 560 /* 561 * end == 0 indicates that the entire range after start should be 562 * unmapped. Note, end is exclusive, whereas the interval tree takes 563 * an inclusive "last". 564 */ 565 vma_interval_tree_foreach(vma, root, start, end ? end - 1 : ULONG_MAX) { 566 unsigned long v_start; 567 unsigned long v_end; 568 569 if (!hugetlb_vma_trylock_write(vma)) 570 continue; 571 572 v_start = vma_offset_start(vma, start); 573 v_end = vma_offset_end(vma, end); 574 575 unmap_hugepage_range(vma, v_start, v_end, NULL, zap_flags); 576 577 /* 578 * Note that vma lock only exists for shared/non-private 579 * vmas. Therefore, lock is not held when calling 580 * unmap_hugepage_range for private vmas. 581 */ 582 hugetlb_vma_unlock_write(vma); 583 } 584} 585 586/* 587 * Called with hugetlb fault mutex held. 588 * Returns true if page was actually removed, false otherwise. 589 */ 590static bool remove_inode_single_folio(struct hstate *h, struct inode *inode, 591 struct address_space *mapping, 592 struct folio *folio, pgoff_t index, 593 bool truncate_op) 594{ 595 bool ret = false; 596 597 /* 598 * If folio is mapped, it was faulted in after being 599 * unmapped in caller. Unmap (again) while holding 600 * the fault mutex. The mutex will prevent faults 601 * until we finish removing the folio. 602 */ 603 if (unlikely(folio_mapped(folio))) 604 hugetlb_unmap_file_folio(h, mapping, folio, index); 605 606 folio_lock(folio); 607 /* 608 * We must remove the folio from page cache before removing 609 * the region/ reserve map (hugetlb_unreserve_pages). In 610 * rare out of memory conditions, removal of the region/reserve 611 * map could fail. Correspondingly, the subpool and global 612 * reserve usage count can need to be adjusted. 613 */ 614 VM_BUG_ON_FOLIO(folio_test_hugetlb_restore_reserve(folio), folio); 615 hugetlb_delete_from_page_cache(folio); 616 ret = true; 617 if (!truncate_op) { 618 if (unlikely(hugetlb_unreserve_pages(inode, index, 619 index + 1, 1))) 620 hugetlb_fix_reserve_counts(inode); 621 } 622 623 folio_unlock(folio); 624 return ret; 625} 626 627/* 628 * remove_inode_hugepages handles two distinct cases: truncation and hole 629 * punch. There are subtle differences in operation for each case. 630 * 631 * truncation is indicated by end of range being LLONG_MAX 632 * In this case, we first scan the range and release found pages. 633 * After releasing pages, hugetlb_unreserve_pages cleans up region/reserve 634 * maps and global counts. Page faults can race with truncation. 635 * During faults, hugetlb_no_page() checks i_size before page allocation, 636 * and again after obtaining page table lock. It will 'back out' 637 * allocations in the truncated range. 638 * hole punch is indicated if end is not LLONG_MAX 639 * In the hole punch case we scan the range and release found pages. 640 * Only when releasing a page is the associated region/reserve map 641 * deleted. The region/reserve map for ranges without associated 642 * pages are not modified. Page faults can race with hole punch. 643 * This is indicated if we find a mapped page. 644 * Note: If the passed end of range value is beyond the end of file, but 645 * not LLONG_MAX this routine still performs a hole punch operation. 646 */ 647static void remove_inode_hugepages(struct inode *inode, loff_t lstart, 648 loff_t lend) 649{ 650 struct hstate *h = hstate_inode(inode); 651 struct address_space *mapping = &inode->i_data; 652 const pgoff_t end = lend >> PAGE_SHIFT; 653 struct folio_batch fbatch; 654 pgoff_t next, index; 655 int i, freed = 0; 656 bool truncate_op = (lend == LLONG_MAX); 657 658 folio_batch_init(&fbatch); 659 next = lstart >> PAGE_SHIFT; 660 while (filemap_get_folios(mapping, &next, end - 1, &fbatch)) { 661 for (i = 0; i < folio_batch_count(&fbatch); ++i) { 662 struct folio *folio = fbatch.folios[i]; 663 u32 hash = 0; 664 665 index = folio->index >> huge_page_order(h); 666 hash = hugetlb_fault_mutex_hash(mapping, index); 667 mutex_lock(&hugetlb_fault_mutex_table[hash]); 668 669 /* 670 * Remove folio that was part of folio_batch. 671 */ 672 if (remove_inode_single_folio(h, inode, mapping, folio, 673 index, truncate_op)) 674 freed++; 675 676 mutex_unlock(&hugetlb_fault_mutex_table[hash]); 677 } 678 folio_batch_release(&fbatch); 679 cond_resched(); 680 } 681 682 if (truncate_op) 683 (void)hugetlb_unreserve_pages(inode, 684 lstart >> huge_page_shift(h), 685 LONG_MAX, freed); 686} 687 688static void hugetlbfs_evict_inode(struct inode *inode) 689{ 690 struct resv_map *resv_map; 691 692 remove_inode_hugepages(inode, 0, LLONG_MAX); 693 694 /* 695 * Get the resv_map from the address space embedded in the inode. 696 * This is the address space which points to any resv_map allocated 697 * at inode creation time. If this is a device special inode, 698 * i_mapping may not point to the original address space. 699 */ 700 resv_map = (struct resv_map *)(&inode->i_data)->i_private_data; 701 /* Only regular and link inodes have associated reserve maps */ 702 if (resv_map) 703 resv_map_release(&resv_map->refs); 704 clear_inode(inode); 705} 706 707static void hugetlb_vmtruncate(struct inode *inode, loff_t offset) 708{ 709 pgoff_t pgoff; 710 struct address_space *mapping = inode->i_mapping; 711 struct hstate *h = hstate_inode(inode); 712 713 BUG_ON(offset & ~huge_page_mask(h)); 714 pgoff = offset >> PAGE_SHIFT; 715 716 i_size_write(inode, offset); 717 i_mmap_lock_write(mapping); 718 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root)) 719 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0, 720 ZAP_FLAG_DROP_MARKER); 721 i_mmap_unlock_write(mapping); 722 remove_inode_hugepages(inode, offset, LLONG_MAX); 723} 724 725static void hugetlbfs_zero_partial_page(struct hstate *h, 726 struct address_space *mapping, 727 loff_t start, 728 loff_t end) 729{ 730 pgoff_t idx = start >> huge_page_shift(h); 731 struct folio *folio; 732 733 folio = filemap_lock_hugetlb_folio(h, mapping, idx); 734 if (IS_ERR(folio)) 735 return; 736 737 start = start & ~huge_page_mask(h); 738 end = end & ~huge_page_mask(h); 739 if (!end) 740 end = huge_page_size(h); 741 742 folio_zero_segment(folio, (size_t)start, (size_t)end); 743 744 folio_unlock(folio); 745 folio_put(folio); 746} 747 748static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) 749{ 750 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode); 751 struct address_space *mapping = inode->i_mapping; 752 struct hstate *h = hstate_inode(inode); 753 loff_t hpage_size = huge_page_size(h); 754 loff_t hole_start, hole_end; 755 756 /* 757 * hole_start and hole_end indicate the full pages within the hole. 758 */ 759 hole_start = round_up(offset, hpage_size); 760 hole_end = round_down(offset + len, hpage_size); 761 762 inode_lock(inode); 763 764 /* protected by i_rwsem */ 765 if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) { 766 inode_unlock(inode); 767 return -EPERM; 768 } 769 770 i_mmap_lock_write(mapping); 771 772 /* If range starts before first full page, zero partial page. */ 773 if (offset < hole_start) 774 hugetlbfs_zero_partial_page(h, mapping, 775 offset, min(offset + len, hole_start)); 776 777 /* Unmap users of full pages in the hole. */ 778 if (hole_end > hole_start) { 779 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root)) 780 hugetlb_vmdelete_list(&mapping->i_mmap, 781 hole_start >> PAGE_SHIFT, 782 hole_end >> PAGE_SHIFT, 0); 783 } 784 785 /* If range extends beyond last full page, zero partial page. */ 786 if ((offset + len) > hole_end && (offset + len) > hole_start) 787 hugetlbfs_zero_partial_page(h, mapping, 788 hole_end, offset + len); 789 790 i_mmap_unlock_write(mapping); 791 792 /* Remove full pages from the file. */ 793 if (hole_end > hole_start) 794 remove_inode_hugepages(inode, hole_start, hole_end); 795 796 inode_unlock(inode); 797 798 return 0; 799} 800 801static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset, 802 loff_t len) 803{ 804 struct inode *inode = file_inode(file); 805 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode); 806 struct address_space *mapping = inode->i_mapping; 807 struct hstate *h = hstate_inode(inode); 808 struct vm_area_struct pseudo_vma; 809 struct mm_struct *mm = current->mm; 810 loff_t hpage_size = huge_page_size(h); 811 unsigned long hpage_shift = huge_page_shift(h); 812 pgoff_t start, index, end; 813 int error; 814 u32 hash; 815 816 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) 817 return -EOPNOTSUPP; 818 819 if (mode & FALLOC_FL_PUNCH_HOLE) 820 return hugetlbfs_punch_hole(inode, offset, len); 821 822 /* 823 * Default preallocate case. 824 * For this range, start is rounded down and end is rounded up 825 * as well as being converted to page offsets. 826 */ 827 start = offset >> hpage_shift; 828 end = (offset + len + hpage_size - 1) >> hpage_shift; 829 830 inode_lock(inode); 831 832 /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */ 833 error = inode_newsize_ok(inode, offset + len); 834 if (error) 835 goto out; 836 837 if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) { 838 error = -EPERM; 839 goto out; 840 } 841 842 /* 843 * Initialize a pseudo vma as this is required by the huge page 844 * allocation routines. 845 */ 846 vma_init(&pseudo_vma, mm); 847 vm_flags_init(&pseudo_vma, VM_HUGETLB | VM_MAYSHARE | VM_SHARED); 848 pseudo_vma.vm_file = file; 849 850 for (index = start; index < end; index++) { 851 /* 852 * This is supposed to be the vaddr where the page is being 853 * faulted in, but we have no vaddr here. 854 */ 855 struct folio *folio; 856 unsigned long addr; 857 858 cond_resched(); 859 860 /* 861 * fallocate(2) manpage permits EINTR; we may have been 862 * interrupted because we are using up too much memory. 863 */ 864 if (signal_pending(current)) { 865 error = -EINTR; 866 break; 867 } 868 869 /* addr is the offset within the file (zero based) */ 870 addr = index * hpage_size; 871 872 /* mutex taken here, fault path and hole punch */ 873 hash = hugetlb_fault_mutex_hash(mapping, index); 874 mutex_lock(&hugetlb_fault_mutex_table[hash]); 875 876 /* See if already present in mapping to avoid alloc/free */ 877 folio = filemap_get_folio(mapping, index << huge_page_order(h)); 878 if (!IS_ERR(folio)) { 879 folio_put(folio); 880 mutex_unlock(&hugetlb_fault_mutex_table[hash]); 881 continue; 882 } 883 884 /* 885 * Allocate folio without setting the avoid_reserve argument. 886 * There certainly are no reserves associated with the 887 * pseudo_vma. However, there could be shared mappings with 888 * reserves for the file at the inode level. If we fallocate 889 * folios in these areas, we need to consume the reserves 890 * to keep reservation accounting consistent. 891 */ 892 folio = alloc_hugetlb_folio(&pseudo_vma, addr, 0); 893 if (IS_ERR(folio)) { 894 mutex_unlock(&hugetlb_fault_mutex_table[hash]); 895 error = PTR_ERR(folio); 896 goto out; 897 } 898 clear_huge_page(&folio->page, addr, pages_per_huge_page(h)); 899 __folio_mark_uptodate(folio); 900 error = hugetlb_add_to_page_cache(folio, mapping, index); 901 if (unlikely(error)) { 902 restore_reserve_on_error(h, &pseudo_vma, addr, folio); 903 folio_put(folio); 904 mutex_unlock(&hugetlb_fault_mutex_table[hash]); 905 goto out; 906 } 907 908 mutex_unlock(&hugetlb_fault_mutex_table[hash]); 909 910 folio_set_hugetlb_migratable(folio); 911 /* 912 * folio_unlock because locked by hugetlb_add_to_page_cache() 913 * folio_put() due to reference from alloc_hugetlb_folio() 914 */ 915 folio_unlock(folio); 916 folio_put(folio); 917 } 918 919 if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) 920 i_size_write(inode, offset + len); 921 inode_set_ctime_current(inode); 922out: 923 inode_unlock(inode); 924 return error; 925} 926 927static int hugetlbfs_setattr(struct mnt_idmap *idmap, 928 struct dentry *dentry, struct iattr *attr) 929{ 930 struct inode *inode = d_inode(dentry); 931 struct hstate *h = hstate_inode(inode); 932 int error; 933 unsigned int ia_valid = attr->ia_valid; 934 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode); 935 936 error = setattr_prepare(idmap, dentry, attr); 937 if (error) 938 return error; 939 940 if (ia_valid & ATTR_SIZE) { 941 loff_t oldsize = inode->i_size; 942 loff_t newsize = attr->ia_size; 943 944 if (newsize & ~huge_page_mask(h)) 945 return -EINVAL; 946 /* protected by i_rwsem */ 947 if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) || 948 (newsize > oldsize && (info->seals & F_SEAL_GROW))) 949 return -EPERM; 950 hugetlb_vmtruncate(inode, newsize); 951 } 952 953 setattr_copy(idmap, inode, attr); 954 mark_inode_dirty(inode); 955 return 0; 956} 957 958static struct inode *hugetlbfs_get_root(struct super_block *sb, 959 struct hugetlbfs_fs_context *ctx) 960{ 961 struct inode *inode; 962 963 inode = new_inode(sb); 964 if (inode) { 965 inode->i_ino = get_next_ino(); 966 inode->i_mode = S_IFDIR | ctx->mode; 967 inode->i_uid = ctx->uid; 968 inode->i_gid = ctx->gid; 969 simple_inode_init_ts(inode); 970 inode->i_op = &hugetlbfs_dir_inode_operations; 971 inode->i_fop = &simple_dir_operations; 972 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 973 inc_nlink(inode); 974 lockdep_annotate_inode_mutex_key(inode); 975 } 976 return inode; 977} 978 979/* 980 * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never 981 * be taken from reclaim -- unlike regular filesystems. This needs an 982 * annotation because huge_pmd_share() does an allocation under hugetlb's 983 * i_mmap_rwsem. 984 */ 985static struct lock_class_key hugetlbfs_i_mmap_rwsem_key; 986 987static struct inode *hugetlbfs_get_inode(struct super_block *sb, 988 struct mnt_idmap *idmap, 989 struct inode *dir, 990 umode_t mode, dev_t dev) 991{ 992 struct inode *inode; 993 struct resv_map *resv_map = NULL; 994 995 /* 996 * Reserve maps are only needed for inodes that can have associated 997 * page allocations. 998 */ 999 if (S_ISREG(mode) || S_ISLNK(mode)) { 1000 resv_map = resv_map_alloc(); 1001 if (!resv_map) 1002 return NULL; 1003 } 1004 1005 inode = new_inode(sb); 1006 if (inode) { 1007 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode); 1008 1009 inode->i_ino = get_next_ino(); 1010 inode_init_owner(idmap, inode, dir, mode); 1011 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem, 1012 &hugetlbfs_i_mmap_rwsem_key); 1013 inode->i_mapping->a_ops = &hugetlbfs_aops; 1014 simple_inode_init_ts(inode); 1015 inode->i_mapping->i_private_data = resv_map; 1016 info->seals = F_SEAL_SEAL; 1017 switch (mode & S_IFMT) { 1018 default: 1019 init_special_inode(inode, mode, dev); 1020 break; 1021 case S_IFREG: 1022 inode->i_op = &hugetlbfs_inode_operations; 1023 inode->i_fop = &hugetlbfs_file_operations; 1024 break; 1025 case S_IFDIR: 1026 inode->i_op = &hugetlbfs_dir_inode_operations; 1027 inode->i_fop = &simple_dir_operations; 1028 1029 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 1030 inc_nlink(inode); 1031 break; 1032 case S_IFLNK: 1033 inode->i_op = &page_symlink_inode_operations; 1034 inode_nohighmem(inode); 1035 break; 1036 } 1037 lockdep_annotate_inode_mutex_key(inode); 1038 } else { 1039 if (resv_map) 1040 kref_put(&resv_map->refs, resv_map_release); 1041 } 1042 1043 return inode; 1044} 1045 1046/* 1047 * File creation. Allocate an inode, and we're done.. 1048 */ 1049static int hugetlbfs_mknod(struct mnt_idmap *idmap, struct inode *dir, 1050 struct dentry *dentry, umode_t mode, dev_t dev) 1051{ 1052 struct inode *inode; 1053 1054 inode = hugetlbfs_get_inode(dir->i_sb, idmap, dir, mode, dev); 1055 if (!inode) 1056 return -ENOSPC; 1057 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); 1058 d_instantiate(dentry, inode); 1059 dget(dentry);/* Extra count - pin the dentry in core */ 1060 return 0; 1061} 1062 1063static int hugetlbfs_mkdir(struct mnt_idmap *idmap, struct inode *dir, 1064 struct dentry *dentry, umode_t mode) 1065{ 1066 int retval = hugetlbfs_mknod(idmap, dir, dentry, 1067 mode | S_IFDIR, 0); 1068 if (!retval) 1069 inc_nlink(dir); 1070 return retval; 1071} 1072 1073static int hugetlbfs_create(struct mnt_idmap *idmap, 1074 struct inode *dir, struct dentry *dentry, 1075 umode_t mode, bool excl) 1076{ 1077 return hugetlbfs_mknod(idmap, dir, dentry, mode | S_IFREG, 0); 1078} 1079 1080static int hugetlbfs_tmpfile(struct mnt_idmap *idmap, 1081 struct inode *dir, struct file *file, 1082 umode_t mode) 1083{ 1084 struct inode *inode; 1085 1086 inode = hugetlbfs_get_inode(dir->i_sb, idmap, dir, mode | S_IFREG, 0); 1087 if (!inode) 1088 return -ENOSPC; 1089 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); 1090 d_tmpfile(file, inode); 1091 return finish_open_simple(file, 0); 1092} 1093 1094static int hugetlbfs_symlink(struct mnt_idmap *idmap, 1095 struct inode *dir, struct dentry *dentry, 1096 const char *symname) 1097{ 1098 const umode_t mode = S_IFLNK|S_IRWXUGO; 1099 struct inode *inode; 1100 int error = -ENOSPC; 1101 1102 inode = hugetlbfs_get_inode(dir->i_sb, idmap, dir, mode, 0); 1103 if (inode) { 1104 int l = strlen(symname)+1; 1105 error = page_symlink(inode, symname, l); 1106 if (!error) { 1107 d_instantiate(dentry, inode); 1108 dget(dentry); 1109 } else 1110 iput(inode); 1111 } 1112 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); 1113 1114 return error; 1115} 1116 1117#ifdef CONFIG_MIGRATION 1118static int hugetlbfs_migrate_folio(struct address_space *mapping, 1119 struct folio *dst, struct folio *src, 1120 enum migrate_mode mode) 1121{ 1122 int rc; 1123 1124 rc = migrate_huge_page_move_mapping(mapping, dst, src); 1125 if (rc != MIGRATEPAGE_SUCCESS) 1126 return rc; 1127 1128 if (hugetlb_folio_subpool(src)) { 1129 hugetlb_set_folio_subpool(dst, 1130 hugetlb_folio_subpool(src)); 1131 hugetlb_set_folio_subpool(src, NULL); 1132 } 1133 1134 if (mode != MIGRATE_SYNC_NO_COPY) 1135 folio_migrate_copy(dst, src); 1136 else 1137 folio_migrate_flags(dst, src); 1138 1139 return MIGRATEPAGE_SUCCESS; 1140} 1141#else 1142#define hugetlbfs_migrate_folio NULL 1143#endif 1144 1145static int hugetlbfs_error_remove_folio(struct address_space *mapping, 1146 struct folio *folio) 1147{ 1148 return 0; 1149} 1150 1151/* 1152 * Display the mount options in /proc/mounts. 1153 */ 1154static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root) 1155{ 1156 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(root->d_sb); 1157 struct hugepage_subpool *spool = sbinfo->spool; 1158 unsigned long hpage_size = huge_page_size(sbinfo->hstate); 1159 unsigned hpage_shift = huge_page_shift(sbinfo->hstate); 1160 char mod; 1161 1162 if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID)) 1163 seq_printf(m, ",uid=%u", 1164 from_kuid_munged(&init_user_ns, sbinfo->uid)); 1165 if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID)) 1166 seq_printf(m, ",gid=%u", 1167 from_kgid_munged(&init_user_ns, sbinfo->gid)); 1168 if (sbinfo->mode != 0755) 1169 seq_printf(m, ",mode=%o", sbinfo->mode); 1170 if (sbinfo->max_inodes != -1) 1171 seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes); 1172 1173 hpage_size /= 1024; 1174 mod = 'K'; 1175 if (hpage_size >= 1024) { 1176 hpage_size /= 1024; 1177 mod = 'M'; 1178 } 1179 seq_printf(m, ",pagesize=%lu%c", hpage_size, mod); 1180 if (spool) { 1181 if (spool->max_hpages != -1) 1182 seq_printf(m, ",size=%llu", 1183 (unsigned long long)spool->max_hpages << hpage_shift); 1184 if (spool->min_hpages != -1) 1185 seq_printf(m, ",min_size=%llu", 1186 (unsigned long long)spool->min_hpages << hpage_shift); 1187 } 1188 return 0; 1189} 1190 1191static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf) 1192{ 1193 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb); 1194 struct hstate *h = hstate_inode(d_inode(dentry)); 1195 u64 id = huge_encode_dev(dentry->d_sb->s_dev); 1196 1197 buf->f_fsid = u64_to_fsid(id); 1198 buf->f_type = HUGETLBFS_MAGIC; 1199 buf->f_bsize = huge_page_size(h); 1200 if (sbinfo) { 1201 spin_lock(&sbinfo->stat_lock); 1202 /* If no limits set, just report 0 or -1 for max/free/used 1203 * blocks, like simple_statfs() */ 1204 if (sbinfo->spool) { 1205 long free_pages; 1206 1207 spin_lock_irq(&sbinfo->spool->lock); 1208 buf->f_blocks = sbinfo->spool->max_hpages; 1209 free_pages = sbinfo->spool->max_hpages 1210 - sbinfo->spool->used_hpages; 1211 buf->f_bavail = buf->f_bfree = free_pages; 1212 spin_unlock_irq(&sbinfo->spool->lock); 1213 buf->f_files = sbinfo->max_inodes; 1214 buf->f_ffree = sbinfo->free_inodes; 1215 } 1216 spin_unlock(&sbinfo->stat_lock); 1217 } 1218 buf->f_namelen = NAME_MAX; 1219 return 0; 1220} 1221 1222static void hugetlbfs_put_super(struct super_block *sb) 1223{ 1224 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb); 1225 1226 if (sbi) { 1227 sb->s_fs_info = NULL; 1228 1229 if (sbi->spool) 1230 hugepage_put_subpool(sbi->spool); 1231 1232 kfree(sbi); 1233 } 1234} 1235 1236static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo) 1237{ 1238 if (sbinfo->free_inodes >= 0) { 1239 spin_lock(&sbinfo->stat_lock); 1240 if (unlikely(!sbinfo->free_inodes)) { 1241 spin_unlock(&sbinfo->stat_lock); 1242 return 0; 1243 } 1244 sbinfo->free_inodes--; 1245 spin_unlock(&sbinfo->stat_lock); 1246 } 1247 1248 return 1; 1249} 1250 1251static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo) 1252{ 1253 if (sbinfo->free_inodes >= 0) { 1254 spin_lock(&sbinfo->stat_lock); 1255 sbinfo->free_inodes++; 1256 spin_unlock(&sbinfo->stat_lock); 1257 } 1258} 1259 1260 1261static struct kmem_cache *hugetlbfs_inode_cachep; 1262 1263static struct inode *hugetlbfs_alloc_inode(struct super_block *sb) 1264{ 1265 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb); 1266 struct hugetlbfs_inode_info *p; 1267 1268 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo))) 1269 return NULL; 1270 p = alloc_inode_sb(sb, hugetlbfs_inode_cachep, GFP_KERNEL); 1271 if (unlikely(!p)) { 1272 hugetlbfs_inc_free_inodes(sbinfo); 1273 return NULL; 1274 } 1275 return &p->vfs_inode; 1276} 1277 1278static void hugetlbfs_free_inode(struct inode *inode) 1279{ 1280 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode)); 1281} 1282 1283static void hugetlbfs_destroy_inode(struct inode *inode) 1284{ 1285 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb)); 1286} 1287 1288static const struct address_space_operations hugetlbfs_aops = { 1289 .write_begin = hugetlbfs_write_begin, 1290 .write_end = hugetlbfs_write_end, 1291 .dirty_folio = noop_dirty_folio, 1292 .migrate_folio = hugetlbfs_migrate_folio, 1293 .error_remove_folio = hugetlbfs_error_remove_folio, 1294}; 1295 1296 1297static void init_once(void *foo) 1298{ 1299 struct hugetlbfs_inode_info *ei = foo; 1300 1301 inode_init_once(&ei->vfs_inode); 1302} 1303 1304const struct file_operations hugetlbfs_file_operations = { 1305 .read_iter = hugetlbfs_read_iter, 1306 .mmap = hugetlbfs_file_mmap, 1307 .fsync = noop_fsync, 1308 .get_unmapped_area = hugetlb_get_unmapped_area, 1309 .llseek = default_llseek, 1310 .fallocate = hugetlbfs_fallocate, 1311}; 1312 1313static const struct inode_operations hugetlbfs_dir_inode_operations = { 1314 .create = hugetlbfs_create, 1315 .lookup = simple_lookup, 1316 .link = simple_link, 1317 .unlink = simple_unlink, 1318 .symlink = hugetlbfs_symlink, 1319 .mkdir = hugetlbfs_mkdir, 1320 .rmdir = simple_rmdir, 1321 .mknod = hugetlbfs_mknod, 1322 .rename = simple_rename, 1323 .setattr = hugetlbfs_setattr, 1324 .tmpfile = hugetlbfs_tmpfile, 1325}; 1326 1327static const struct inode_operations hugetlbfs_inode_operations = { 1328 .setattr = hugetlbfs_setattr, 1329}; 1330 1331static const struct super_operations hugetlbfs_ops = { 1332 .alloc_inode = hugetlbfs_alloc_inode, 1333 .free_inode = hugetlbfs_free_inode, 1334 .destroy_inode = hugetlbfs_destroy_inode, 1335 .evict_inode = hugetlbfs_evict_inode, 1336 .statfs = hugetlbfs_statfs, 1337 .put_super = hugetlbfs_put_super, 1338 .show_options = hugetlbfs_show_options, 1339}; 1340 1341/* 1342 * Convert size option passed from command line to number of huge pages 1343 * in the pool specified by hstate. Size option could be in bytes 1344 * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT). 1345 */ 1346static long 1347hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt, 1348 enum hugetlbfs_size_type val_type) 1349{ 1350 if (val_type == NO_SIZE) 1351 return -1; 1352 1353 if (val_type == SIZE_PERCENT) { 1354 size_opt <<= huge_page_shift(h); 1355 size_opt *= h->max_huge_pages; 1356 do_div(size_opt, 100); 1357 } 1358 1359 size_opt >>= huge_page_shift(h); 1360 return size_opt; 1361} 1362 1363/* 1364 * Parse one mount parameter. 1365 */ 1366static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *param) 1367{ 1368 struct hugetlbfs_fs_context *ctx = fc->fs_private; 1369 struct fs_parse_result result; 1370 struct hstate *h; 1371 char *rest; 1372 unsigned long ps; 1373 int opt; 1374 1375 opt = fs_parse(fc, hugetlb_fs_parameters, param, &result); 1376 if (opt < 0) 1377 return opt; 1378 1379 switch (opt) { 1380 case Opt_uid: 1381 ctx->uid = make_kuid(current_user_ns(), result.uint_32); 1382 if (!uid_valid(ctx->uid)) 1383 goto bad_val; 1384 return 0; 1385 1386 case Opt_gid: 1387 ctx->gid = make_kgid(current_user_ns(), result.uint_32); 1388 if (!gid_valid(ctx->gid)) 1389 goto bad_val; 1390 return 0; 1391 1392 case Opt_mode: 1393 ctx->mode = result.uint_32 & 01777U; 1394 return 0; 1395 1396 case Opt_size: 1397 /* memparse() will accept a K/M/G without a digit */ 1398 if (!param->string || !isdigit(param->string[0])) 1399 goto bad_val; 1400 ctx->max_size_opt = memparse(param->string, &rest); 1401 ctx->max_val_type = SIZE_STD; 1402 if (*rest == '%') 1403 ctx->max_val_type = SIZE_PERCENT; 1404 return 0; 1405 1406 case Opt_nr_inodes: 1407 /* memparse() will accept a K/M/G without a digit */ 1408 if (!param->string || !isdigit(param->string[0])) 1409 goto bad_val; 1410 ctx->nr_inodes = memparse(param->string, &rest); 1411 return 0; 1412 1413 case Opt_pagesize: 1414 ps = memparse(param->string, &rest); 1415 h = size_to_hstate(ps); 1416 if (!h) { 1417 pr_err("Unsupported page size %lu MB\n", ps / SZ_1M); 1418 return -EINVAL; 1419 } 1420 ctx->hstate = h; 1421 return 0; 1422 1423 case Opt_min_size: 1424 /* memparse() will accept a K/M/G without a digit */ 1425 if (!param->string || !isdigit(param->string[0])) 1426 goto bad_val; 1427 ctx->min_size_opt = memparse(param->string, &rest); 1428 ctx->min_val_type = SIZE_STD; 1429 if (*rest == '%') 1430 ctx->min_val_type = SIZE_PERCENT; 1431 return 0; 1432 1433 default: 1434 return -EINVAL; 1435 } 1436 1437bad_val: 1438 return invalfc(fc, "Bad value '%s' for mount option '%s'\n", 1439 param->string, param->key); 1440} 1441 1442/* 1443 * Validate the parsed options. 1444 */ 1445static int hugetlbfs_validate(struct fs_context *fc) 1446{ 1447 struct hugetlbfs_fs_context *ctx = fc->fs_private; 1448 1449 /* 1450 * Use huge page pool size (in hstate) to convert the size 1451 * options to number of huge pages. If NO_SIZE, -1 is returned. 1452 */ 1453 ctx->max_hpages = hugetlbfs_size_to_hpages(ctx->hstate, 1454 ctx->max_size_opt, 1455 ctx->max_val_type); 1456 ctx->min_hpages = hugetlbfs_size_to_hpages(ctx->hstate, 1457 ctx->min_size_opt, 1458 ctx->min_val_type); 1459 1460 /* 1461 * If max_size was specified, then min_size must be smaller 1462 */ 1463 if (ctx->max_val_type > NO_SIZE && 1464 ctx->min_hpages > ctx->max_hpages) { 1465 pr_err("Minimum size can not be greater than maximum size\n"); 1466 return -EINVAL; 1467 } 1468 1469 return 0; 1470} 1471 1472static int 1473hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc) 1474{ 1475 struct hugetlbfs_fs_context *ctx = fc->fs_private; 1476 struct hugetlbfs_sb_info *sbinfo; 1477 1478 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL); 1479 if (!sbinfo) 1480 return -ENOMEM; 1481 sb->s_fs_info = sbinfo; 1482 spin_lock_init(&sbinfo->stat_lock); 1483 sbinfo->hstate = ctx->hstate; 1484 sbinfo->max_inodes = ctx->nr_inodes; 1485 sbinfo->free_inodes = ctx->nr_inodes; 1486 sbinfo->spool = NULL; 1487 sbinfo->uid = ctx->uid; 1488 sbinfo->gid = ctx->gid; 1489 sbinfo->mode = ctx->mode; 1490 1491 /* 1492 * Allocate and initialize subpool if maximum or minimum size is 1493 * specified. Any needed reservations (for minimum size) are taken 1494 * when the subpool is created. 1495 */ 1496 if (ctx->max_hpages != -1 || ctx->min_hpages != -1) { 1497 sbinfo->spool = hugepage_new_subpool(ctx->hstate, 1498 ctx->max_hpages, 1499 ctx->min_hpages); 1500 if (!sbinfo->spool) 1501 goto out_free; 1502 } 1503 sb->s_maxbytes = MAX_LFS_FILESIZE; 1504 sb->s_blocksize = huge_page_size(ctx->hstate); 1505 sb->s_blocksize_bits = huge_page_shift(ctx->hstate); 1506 sb->s_magic = HUGETLBFS_MAGIC; 1507 sb->s_op = &hugetlbfs_ops; 1508 sb->s_time_gran = 1; 1509 1510 /* 1511 * Due to the special and limited functionality of hugetlbfs, it does 1512 * not work well as a stacking filesystem. 1513 */ 1514 sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH; 1515 sb->s_root = d_make_root(hugetlbfs_get_root(sb, ctx)); 1516 if (!sb->s_root) 1517 goto out_free; 1518 return 0; 1519out_free: 1520 kfree(sbinfo->spool); 1521 kfree(sbinfo); 1522 return -ENOMEM; 1523} 1524 1525static int hugetlbfs_get_tree(struct fs_context *fc) 1526{ 1527 int err = hugetlbfs_validate(fc); 1528 if (err) 1529 return err; 1530 return get_tree_nodev(fc, hugetlbfs_fill_super); 1531} 1532 1533static void hugetlbfs_fs_context_free(struct fs_context *fc) 1534{ 1535 kfree(fc->fs_private); 1536} 1537 1538static const struct fs_context_operations hugetlbfs_fs_context_ops = { 1539 .free = hugetlbfs_fs_context_free, 1540 .parse_param = hugetlbfs_parse_param, 1541 .get_tree = hugetlbfs_get_tree, 1542}; 1543 1544static int hugetlbfs_init_fs_context(struct fs_context *fc) 1545{ 1546 struct hugetlbfs_fs_context *ctx; 1547 1548 ctx = kzalloc(sizeof(struct hugetlbfs_fs_context), GFP_KERNEL); 1549 if (!ctx) 1550 return -ENOMEM; 1551 1552 ctx->max_hpages = -1; /* No limit on size by default */ 1553 ctx->nr_inodes = -1; /* No limit on number of inodes by default */ 1554 ctx->uid = current_fsuid(); 1555 ctx->gid = current_fsgid(); 1556 ctx->mode = 0755; 1557 ctx->hstate = &default_hstate; 1558 ctx->min_hpages = -1; /* No default minimum size */ 1559 ctx->max_val_type = NO_SIZE; 1560 ctx->min_val_type = NO_SIZE; 1561 fc->fs_private = ctx; 1562 fc->ops = &hugetlbfs_fs_context_ops; 1563 return 0; 1564} 1565 1566static struct file_system_type hugetlbfs_fs_type = { 1567 .name = "hugetlbfs", 1568 .init_fs_context = hugetlbfs_init_fs_context, 1569 .parameters = hugetlb_fs_parameters, 1570 .kill_sb = kill_litter_super, 1571 .fs_flags = FS_ALLOW_IDMAP, 1572}; 1573 1574static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE]; 1575 1576static int can_do_hugetlb_shm(void) 1577{ 1578 kgid_t shm_group; 1579 shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group); 1580 return capable(CAP_IPC_LOCK) || in_group_p(shm_group); 1581} 1582 1583static int get_hstate_idx(int page_size_log) 1584{ 1585 struct hstate *h = hstate_sizelog(page_size_log); 1586 1587 if (!h) 1588 return -1; 1589 return hstate_index(h); 1590} 1591 1592/* 1593 * Note that size should be aligned to proper hugepage size in caller side, 1594 * otherwise hugetlb_reserve_pages reserves one less hugepages than intended. 1595 */ 1596struct file *hugetlb_file_setup(const char *name, size_t size, 1597 vm_flags_t acctflag, int creat_flags, 1598 int page_size_log) 1599{ 1600 struct inode *inode; 1601 struct vfsmount *mnt; 1602 int hstate_idx; 1603 struct file *file; 1604 1605 hstate_idx = get_hstate_idx(page_size_log); 1606 if (hstate_idx < 0) 1607 return ERR_PTR(-ENODEV); 1608 1609 mnt = hugetlbfs_vfsmount[hstate_idx]; 1610 if (!mnt) 1611 return ERR_PTR(-ENOENT); 1612 1613 if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) { 1614 struct ucounts *ucounts = current_ucounts(); 1615 1616 if (user_shm_lock(size, ucounts)) { 1617 pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is obsolete\n", 1618 current->comm, current->pid); 1619 user_shm_unlock(size, ucounts); 1620 } 1621 return ERR_PTR(-EPERM); 1622 } 1623 1624 file = ERR_PTR(-ENOSPC); 1625 /* hugetlbfs_vfsmount[] mounts do not use idmapped mounts. */ 1626 inode = hugetlbfs_get_inode(mnt->mnt_sb, &nop_mnt_idmap, NULL, 1627 S_IFREG | S_IRWXUGO, 0); 1628 if (!inode) 1629 goto out; 1630 if (creat_flags == HUGETLB_SHMFS_INODE) 1631 inode->i_flags |= S_PRIVATE; 1632 1633 inode->i_size = size; 1634 clear_nlink(inode); 1635 1636 if (!hugetlb_reserve_pages(inode, 0, 1637 size >> huge_page_shift(hstate_inode(inode)), NULL, 1638 acctflag)) 1639 file = ERR_PTR(-ENOMEM); 1640 else 1641 file = alloc_file_pseudo(inode, mnt, name, O_RDWR, 1642 &hugetlbfs_file_operations); 1643 if (!IS_ERR(file)) 1644 return file; 1645 1646 iput(inode); 1647out: 1648 return file; 1649} 1650 1651static struct vfsmount *__init mount_one_hugetlbfs(struct hstate *h) 1652{ 1653 struct fs_context *fc; 1654 struct vfsmount *mnt; 1655 1656 fc = fs_context_for_mount(&hugetlbfs_fs_type, SB_KERNMOUNT); 1657 if (IS_ERR(fc)) { 1658 mnt = ERR_CAST(fc); 1659 } else { 1660 struct hugetlbfs_fs_context *ctx = fc->fs_private; 1661 ctx->hstate = h; 1662 mnt = fc_mount(fc); 1663 put_fs_context(fc); 1664 } 1665 if (IS_ERR(mnt)) 1666 pr_err("Cannot mount internal hugetlbfs for page size %luK", 1667 huge_page_size(h) / SZ_1K); 1668 return mnt; 1669} 1670 1671static int __init init_hugetlbfs_fs(void) 1672{ 1673 struct vfsmount *mnt; 1674 struct hstate *h; 1675 int error; 1676 int i; 1677 1678 if (!hugepages_supported()) { 1679 pr_info("disabling because there are no supported hugepage sizes\n"); 1680 return -ENOTSUPP; 1681 } 1682 1683 error = -ENOMEM; 1684 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache", 1685 sizeof(struct hugetlbfs_inode_info), 1686 0, SLAB_ACCOUNT, init_once); 1687 if (hugetlbfs_inode_cachep == NULL) 1688 goto out; 1689 1690 error = register_filesystem(&hugetlbfs_fs_type); 1691 if (error) 1692 goto out_free; 1693 1694 /* default hstate mount is required */ 1695 mnt = mount_one_hugetlbfs(&default_hstate); 1696 if (IS_ERR(mnt)) { 1697 error = PTR_ERR(mnt); 1698 goto out_unreg; 1699 } 1700 hugetlbfs_vfsmount[default_hstate_idx] = mnt; 1701 1702 /* other hstates are optional */ 1703 i = 0; 1704 for_each_hstate(h) { 1705 if (i == default_hstate_idx) { 1706 i++; 1707 continue; 1708 } 1709 1710 mnt = mount_one_hugetlbfs(h); 1711 if (IS_ERR(mnt)) 1712 hugetlbfs_vfsmount[i] = NULL; 1713 else 1714 hugetlbfs_vfsmount[i] = mnt; 1715 i++; 1716 } 1717 1718 return 0; 1719 1720 out_unreg: 1721 (void)unregister_filesystem(&hugetlbfs_fs_type); 1722 out_free: 1723 kmem_cache_destroy(hugetlbfs_inode_cachep); 1724 out: 1725 return error; 1726} 1727fs_initcall(init_hugetlbfs_fs) 1728