1 /* 2 * hugetlbpage-backed filesystem. Based on ramfs. 3 * 4 * Nadia Yvette Chambers, 2002 5 * 6 * Copyright (C) 2002 Linus Torvalds. 7 */ 8 9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 10 11 #include <linux/module.h> 12 #include <linux/thread_info.h> 13 #include <asm/current.h> 14 #include <linux/sched.h> /* remove ASAP */ 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/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 38 #include <asm/uaccess.h> 39 40 static const struct super_operations hugetlbfs_ops; 41 static const struct address_space_operations hugetlbfs_aops; 42 const struct file_operations hugetlbfs_file_operations; 43 static const struct inode_operations hugetlbfs_dir_inode_operations; 44 static const struct inode_operations hugetlbfs_inode_operations; 45 46 struct hugetlbfs_config { 47 kuid_t uid; 48 kgid_t gid; 49 umode_t mode; 50 long nr_blocks; 51 long nr_inodes; 52 struct hstate *hstate; 53 }; 54 55 struct hugetlbfs_inode_info { 56 struct shared_policy policy; 57 struct inode vfs_inode; 58 }; 59 60 static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode) 61 { 62 return container_of(inode, struct hugetlbfs_inode_info, vfs_inode); 63 } 64 65 static struct backing_dev_info hugetlbfs_backing_dev_info = { 66 .name = "hugetlbfs", 67 .ra_pages = 0, /* No readahead */ 68 .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, 69 }; 70 71 int sysctl_hugetlb_shm_group; 72 73 enum { 74 Opt_size, Opt_nr_inodes, 75 Opt_mode, Opt_uid, Opt_gid, 76 Opt_pagesize, 77 Opt_err, 78 }; 79 80 static const match_table_t tokens = { 81 {Opt_size, "size=%s"}, 82 {Opt_nr_inodes, "nr_inodes=%s"}, 83 {Opt_mode, "mode=%o"}, 84 {Opt_uid, "uid=%u"}, 85 {Opt_gid, "gid=%u"}, 86 {Opt_pagesize, "pagesize=%s"}, 87 {Opt_err, NULL}, 88 }; 89 90 static void huge_pagevec_release(struct pagevec *pvec) 91 { 92 int i; 93 94 for (i = 0; i < pagevec_count(pvec); ++i) 95 put_page(pvec->pages[i]); 96 97 pagevec_reinit(pvec); 98 } 99 100 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma) 101 { 102 struct inode *inode = file_inode(file); 103 loff_t len, vma_len; 104 int ret; 105 struct hstate *h = hstate_file(file); 106 107 /* 108 * vma address alignment (but not the pgoff alignment) has 109 * already been checked by prepare_hugepage_range. If you add 110 * any error returns here, do so after setting VM_HUGETLB, so 111 * is_vm_hugetlb_page tests below unmap_region go the right 112 * way when do_mmap_pgoff unwinds (may be important on powerpc 113 * and ia64). 114 */ 115 vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND; 116 vma->vm_ops = &hugetlb_vm_ops; 117 118 if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT)) 119 return -EINVAL; 120 121 vma_len = (loff_t)(vma->vm_end - vma->vm_start); 122 123 mutex_lock(&inode->i_mutex); 124 file_accessed(file); 125 126 ret = -ENOMEM; 127 len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); 128 129 if (hugetlb_reserve_pages(inode, 130 vma->vm_pgoff >> huge_page_order(h), 131 len >> huge_page_shift(h), vma, 132 vma->vm_flags)) 133 goto out; 134 135 ret = 0; 136 hugetlb_prefault_arch_hook(vma->vm_mm); 137 if (vma->vm_flags & VM_WRITE && inode->i_size < len) 138 inode->i_size = len; 139 out: 140 mutex_unlock(&inode->i_mutex); 141 142 return ret; 143 } 144 145 /* 146 * Called under down_write(mmap_sem). 147 */ 148 149 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA 150 static unsigned long 151 hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 152 unsigned long len, unsigned long pgoff, unsigned long flags) 153 { 154 struct mm_struct *mm = current->mm; 155 struct vm_area_struct *vma; 156 struct hstate *h = hstate_file(file); 157 struct vm_unmapped_area_info info; 158 159 if (len & ~huge_page_mask(h)) 160 return -EINVAL; 161 if (len > TASK_SIZE) 162 return -ENOMEM; 163 164 if (flags & MAP_FIXED) { 165 if (prepare_hugepage_range(file, addr, len)) 166 return -EINVAL; 167 return addr; 168 } 169 170 if (addr) { 171 addr = ALIGN(addr, huge_page_size(h)); 172 vma = find_vma(mm, addr); 173 if (TASK_SIZE - len >= addr && 174 (!vma || addr + len <= vma->vm_start)) 175 return addr; 176 } 177 178 info.flags = 0; 179 info.length = len; 180 info.low_limit = TASK_UNMAPPED_BASE; 181 info.high_limit = TASK_SIZE; 182 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 183 info.align_offset = 0; 184 return vm_unmapped_area(&info); 185 } 186 #endif 187 188 static int 189 hugetlbfs_read_actor(struct page *page, unsigned long offset, 190 char __user *buf, unsigned long count, 191 unsigned long size) 192 { 193 char *kaddr; 194 unsigned long left, copied = 0; 195 int i, chunksize; 196 197 if (size > count) 198 size = count; 199 200 /* Find which 4k chunk and offset with in that chunk */ 201 i = offset >> PAGE_CACHE_SHIFT; 202 offset = offset & ~PAGE_CACHE_MASK; 203 204 while (size) { 205 chunksize = PAGE_CACHE_SIZE; 206 if (offset) 207 chunksize -= offset; 208 if (chunksize > size) 209 chunksize = size; 210 kaddr = kmap(&page[i]); 211 left = __copy_to_user(buf, kaddr + offset, chunksize); 212 kunmap(&page[i]); 213 if (left) { 214 copied += (chunksize - left); 215 break; 216 } 217 offset = 0; 218 size -= chunksize; 219 buf += chunksize; 220 copied += chunksize; 221 i++; 222 } 223 return copied ? copied : -EFAULT; 224 } 225 226 /* 227 * Support for read() - Find the page attached to f_mapping and copy out the 228 * data. Its *very* similar to do_generic_mapping_read(), we can't use that 229 * since it has PAGE_CACHE_SIZE assumptions. 230 */ 231 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf, 232 size_t len, loff_t *ppos) 233 { 234 struct hstate *h = hstate_file(filp); 235 struct address_space *mapping = filp->f_mapping; 236 struct inode *inode = mapping->host; 237 unsigned long index = *ppos >> huge_page_shift(h); 238 unsigned long offset = *ppos & ~huge_page_mask(h); 239 unsigned long end_index; 240 loff_t isize; 241 ssize_t retval = 0; 242 243 /* validate length */ 244 if (len == 0) 245 goto out; 246 247 for (;;) { 248 struct page *page; 249 unsigned long nr, ret; 250 int ra; 251 252 /* nr is the maximum number of bytes to copy from this page */ 253 nr = huge_page_size(h); 254 isize = i_size_read(inode); 255 if (!isize) 256 goto out; 257 end_index = (isize - 1) >> huge_page_shift(h); 258 if (index >= end_index) { 259 if (index > end_index) 260 goto out; 261 nr = ((isize - 1) & ~huge_page_mask(h)) + 1; 262 if (nr <= offset) 263 goto out; 264 } 265 nr = nr - offset; 266 267 /* Find the page */ 268 page = find_lock_page(mapping, index); 269 if (unlikely(page == NULL)) { 270 /* 271 * We have a HOLE, zero out the user-buffer for the 272 * length of the hole or request. 273 */ 274 ret = len < nr ? len : nr; 275 if (clear_user(buf, ret)) 276 ra = -EFAULT; 277 else 278 ra = 0; 279 } else { 280 unlock_page(page); 281 282 /* 283 * We have the page, copy it to user space buffer. 284 */ 285 ra = hugetlbfs_read_actor(page, offset, buf, len, nr); 286 ret = ra; 287 page_cache_release(page); 288 } 289 if (ra < 0) { 290 if (retval == 0) 291 retval = ra; 292 goto out; 293 } 294 295 offset += ret; 296 retval += ret; 297 len -= ret; 298 index += offset >> huge_page_shift(h); 299 offset &= ~huge_page_mask(h); 300 301 /* short read or no more work */ 302 if ((ret != nr) || (len == 0)) 303 break; 304 } 305 out: 306 *ppos = ((loff_t)index << huge_page_shift(h)) + offset; 307 return retval; 308 } 309 310 static int hugetlbfs_write_begin(struct file *file, 311 struct address_space *mapping, 312 loff_t pos, unsigned len, unsigned flags, 313 struct page **pagep, void **fsdata) 314 { 315 return -EINVAL; 316 } 317 318 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping, 319 loff_t pos, unsigned len, unsigned copied, 320 struct page *page, void *fsdata) 321 { 322 BUG(); 323 return -EINVAL; 324 } 325 326 static void truncate_huge_page(struct page *page) 327 { 328 cancel_dirty_page(page, /* No IO accounting for huge pages? */0); 329 ClearPageUptodate(page); 330 delete_from_page_cache(page); 331 } 332 333 static void truncate_hugepages(struct inode *inode, loff_t lstart) 334 { 335 struct hstate *h = hstate_inode(inode); 336 struct address_space *mapping = &inode->i_data; 337 const pgoff_t start = lstart >> huge_page_shift(h); 338 struct pagevec pvec; 339 pgoff_t next; 340 int i, freed = 0; 341 342 pagevec_init(&pvec, 0); 343 next = start; 344 while (1) { 345 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { 346 if (next == start) 347 break; 348 next = start; 349 continue; 350 } 351 352 for (i = 0; i < pagevec_count(&pvec); ++i) { 353 struct page *page = pvec.pages[i]; 354 355 lock_page(page); 356 if (page->index > next) 357 next = page->index; 358 ++next; 359 truncate_huge_page(page); 360 unlock_page(page); 361 freed++; 362 } 363 huge_pagevec_release(&pvec); 364 } 365 BUG_ON(!lstart && mapping->nrpages); 366 hugetlb_unreserve_pages(inode, start, freed); 367 } 368 369 static void hugetlbfs_evict_inode(struct inode *inode) 370 { 371 struct resv_map *resv_map; 372 373 truncate_hugepages(inode, 0); 374 resv_map = (struct resv_map *)inode->i_mapping->private_data; 375 /* root inode doesn't have the resv_map, so we should check it */ 376 if (resv_map) 377 resv_map_release(&resv_map->refs); 378 clear_inode(inode); 379 } 380 381 static inline void 382 hugetlb_vmtruncate_list(struct rb_root *root, pgoff_t pgoff) 383 { 384 struct vm_area_struct *vma; 385 386 vma_interval_tree_foreach(vma, root, pgoff, ULONG_MAX) { 387 unsigned long v_offset; 388 389 /* 390 * Can the expression below overflow on 32-bit arches? 391 * No, because the interval tree returns us only those vmas 392 * which overlap the truncated area starting at pgoff, 393 * and no vma on a 32-bit arch can span beyond the 4GB. 394 */ 395 if (vma->vm_pgoff < pgoff) 396 v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT; 397 else 398 v_offset = 0; 399 400 unmap_hugepage_range(vma, vma->vm_start + v_offset, 401 vma->vm_end, NULL); 402 } 403 } 404 405 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset) 406 { 407 pgoff_t pgoff; 408 struct address_space *mapping = inode->i_mapping; 409 struct hstate *h = hstate_inode(inode); 410 411 BUG_ON(offset & ~huge_page_mask(h)); 412 pgoff = offset >> PAGE_SHIFT; 413 414 i_size_write(inode, offset); 415 mutex_lock(&mapping->i_mmap_mutex); 416 if (!RB_EMPTY_ROOT(&mapping->i_mmap)) 417 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff); 418 mutex_unlock(&mapping->i_mmap_mutex); 419 truncate_hugepages(inode, offset); 420 return 0; 421 } 422 423 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr) 424 { 425 struct inode *inode = dentry->d_inode; 426 struct hstate *h = hstate_inode(inode); 427 int error; 428 unsigned int ia_valid = attr->ia_valid; 429 430 BUG_ON(!inode); 431 432 error = inode_change_ok(inode, attr); 433 if (error) 434 return error; 435 436 if (ia_valid & ATTR_SIZE) { 437 error = -EINVAL; 438 if (attr->ia_size & ~huge_page_mask(h)) 439 return -EINVAL; 440 error = hugetlb_vmtruncate(inode, attr->ia_size); 441 if (error) 442 return error; 443 } 444 445 setattr_copy(inode, attr); 446 mark_inode_dirty(inode); 447 return 0; 448 } 449 450 static struct inode *hugetlbfs_get_root(struct super_block *sb, 451 struct hugetlbfs_config *config) 452 { 453 struct inode *inode; 454 455 inode = new_inode(sb); 456 if (inode) { 457 struct hugetlbfs_inode_info *info; 458 inode->i_ino = get_next_ino(); 459 inode->i_mode = S_IFDIR | config->mode; 460 inode->i_uid = config->uid; 461 inode->i_gid = config->gid; 462 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 463 info = HUGETLBFS_I(inode); 464 mpol_shared_policy_init(&info->policy, NULL); 465 inode->i_op = &hugetlbfs_dir_inode_operations; 466 inode->i_fop = &simple_dir_operations; 467 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 468 inc_nlink(inode); 469 lockdep_annotate_inode_mutex_key(inode); 470 } 471 return inode; 472 } 473 474 /* 475 * Hugetlbfs is not reclaimable; therefore its i_mmap_mutex will never 476 * be taken from reclaim -- unlike regular filesystems. This needs an 477 * annotation because huge_pmd_share() does an allocation under 478 * i_mmap_mutex. 479 */ 480 static struct lock_class_key hugetlbfs_i_mmap_mutex_key; 481 482 static struct inode *hugetlbfs_get_inode(struct super_block *sb, 483 struct inode *dir, 484 umode_t mode, dev_t dev) 485 { 486 struct inode *inode; 487 struct resv_map *resv_map; 488 489 resv_map = resv_map_alloc(); 490 if (!resv_map) 491 return NULL; 492 493 inode = new_inode(sb); 494 if (inode) { 495 struct hugetlbfs_inode_info *info; 496 inode->i_ino = get_next_ino(); 497 inode_init_owner(inode, dir, mode); 498 lockdep_set_class(&inode->i_mapping->i_mmap_mutex, 499 &hugetlbfs_i_mmap_mutex_key); 500 inode->i_mapping->a_ops = &hugetlbfs_aops; 501 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info; 502 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 503 inode->i_mapping->private_data = resv_map; 504 info = HUGETLBFS_I(inode); 505 /* 506 * The policy is initialized here even if we are creating a 507 * private inode because initialization simply creates an 508 * an empty rb tree and calls spin_lock_init(), later when we 509 * call mpol_free_shared_policy() it will just return because 510 * the rb tree will still be empty. 511 */ 512 mpol_shared_policy_init(&info->policy, NULL); 513 switch (mode & S_IFMT) { 514 default: 515 init_special_inode(inode, mode, dev); 516 break; 517 case S_IFREG: 518 inode->i_op = &hugetlbfs_inode_operations; 519 inode->i_fop = &hugetlbfs_file_operations; 520 break; 521 case S_IFDIR: 522 inode->i_op = &hugetlbfs_dir_inode_operations; 523 inode->i_fop = &simple_dir_operations; 524 525 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 526 inc_nlink(inode); 527 break; 528 case S_IFLNK: 529 inode->i_op = &page_symlink_inode_operations; 530 break; 531 } 532 lockdep_annotate_inode_mutex_key(inode); 533 } else 534 kref_put(&resv_map->refs, resv_map_release); 535 536 return inode; 537 } 538 539 /* 540 * File creation. Allocate an inode, and we're done.. 541 */ 542 static int hugetlbfs_mknod(struct inode *dir, 543 struct dentry *dentry, umode_t mode, dev_t dev) 544 { 545 struct inode *inode; 546 int error = -ENOSPC; 547 548 inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev); 549 if (inode) { 550 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 551 d_instantiate(dentry, inode); 552 dget(dentry); /* Extra count - pin the dentry in core */ 553 error = 0; 554 } 555 return error; 556 } 557 558 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 559 { 560 int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0); 561 if (!retval) 562 inc_nlink(dir); 563 return retval; 564 } 565 566 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) 567 { 568 return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0); 569 } 570 571 static int hugetlbfs_symlink(struct inode *dir, 572 struct dentry *dentry, const char *symname) 573 { 574 struct inode *inode; 575 int error = -ENOSPC; 576 577 inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0); 578 if (inode) { 579 int l = strlen(symname)+1; 580 error = page_symlink(inode, symname, l); 581 if (!error) { 582 d_instantiate(dentry, inode); 583 dget(dentry); 584 } else 585 iput(inode); 586 } 587 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 588 589 return error; 590 } 591 592 /* 593 * mark the head page dirty 594 */ 595 static int hugetlbfs_set_page_dirty(struct page *page) 596 { 597 struct page *head = compound_head(page); 598 599 SetPageDirty(head); 600 return 0; 601 } 602 603 static int hugetlbfs_migrate_page(struct address_space *mapping, 604 struct page *newpage, struct page *page, 605 enum migrate_mode mode) 606 { 607 int rc; 608 609 rc = migrate_huge_page_move_mapping(mapping, newpage, page); 610 if (rc != MIGRATEPAGE_SUCCESS) 611 return rc; 612 migrate_page_copy(newpage, page); 613 614 return MIGRATEPAGE_SUCCESS; 615 } 616 617 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf) 618 { 619 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb); 620 struct hstate *h = hstate_inode(dentry->d_inode); 621 622 buf->f_type = HUGETLBFS_MAGIC; 623 buf->f_bsize = huge_page_size(h); 624 if (sbinfo) { 625 spin_lock(&sbinfo->stat_lock); 626 /* If no limits set, just report 0 for max/free/used 627 * blocks, like simple_statfs() */ 628 if (sbinfo->spool) { 629 long free_pages; 630 631 spin_lock(&sbinfo->spool->lock); 632 buf->f_blocks = sbinfo->spool->max_hpages; 633 free_pages = sbinfo->spool->max_hpages 634 - sbinfo->spool->used_hpages; 635 buf->f_bavail = buf->f_bfree = free_pages; 636 spin_unlock(&sbinfo->spool->lock); 637 buf->f_files = sbinfo->max_inodes; 638 buf->f_ffree = sbinfo->free_inodes; 639 } 640 spin_unlock(&sbinfo->stat_lock); 641 } 642 buf->f_namelen = NAME_MAX; 643 return 0; 644 } 645 646 static void hugetlbfs_put_super(struct super_block *sb) 647 { 648 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb); 649 650 if (sbi) { 651 sb->s_fs_info = NULL; 652 653 if (sbi->spool) 654 hugepage_put_subpool(sbi->spool); 655 656 kfree(sbi); 657 } 658 } 659 660 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo) 661 { 662 if (sbinfo->free_inodes >= 0) { 663 spin_lock(&sbinfo->stat_lock); 664 if (unlikely(!sbinfo->free_inodes)) { 665 spin_unlock(&sbinfo->stat_lock); 666 return 0; 667 } 668 sbinfo->free_inodes--; 669 spin_unlock(&sbinfo->stat_lock); 670 } 671 672 return 1; 673 } 674 675 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo) 676 { 677 if (sbinfo->free_inodes >= 0) { 678 spin_lock(&sbinfo->stat_lock); 679 sbinfo->free_inodes++; 680 spin_unlock(&sbinfo->stat_lock); 681 } 682 } 683 684 685 static struct kmem_cache *hugetlbfs_inode_cachep; 686 687 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb) 688 { 689 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb); 690 struct hugetlbfs_inode_info *p; 691 692 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo))) 693 return NULL; 694 p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL); 695 if (unlikely(!p)) { 696 hugetlbfs_inc_free_inodes(sbinfo); 697 return NULL; 698 } 699 return &p->vfs_inode; 700 } 701 702 static void hugetlbfs_i_callback(struct rcu_head *head) 703 { 704 struct inode *inode = container_of(head, struct inode, i_rcu); 705 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode)); 706 } 707 708 static void hugetlbfs_destroy_inode(struct inode *inode) 709 { 710 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb)); 711 mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy); 712 call_rcu(&inode->i_rcu, hugetlbfs_i_callback); 713 } 714 715 static const struct address_space_operations hugetlbfs_aops = { 716 .write_begin = hugetlbfs_write_begin, 717 .write_end = hugetlbfs_write_end, 718 .set_page_dirty = hugetlbfs_set_page_dirty, 719 .migratepage = hugetlbfs_migrate_page, 720 }; 721 722 723 static void init_once(void *foo) 724 { 725 struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo; 726 727 inode_init_once(&ei->vfs_inode); 728 } 729 730 const struct file_operations hugetlbfs_file_operations = { 731 .read = hugetlbfs_read, 732 .mmap = hugetlbfs_file_mmap, 733 .fsync = noop_fsync, 734 .get_unmapped_area = hugetlb_get_unmapped_area, 735 .llseek = default_llseek, 736 }; 737 738 static const struct inode_operations hugetlbfs_dir_inode_operations = { 739 .create = hugetlbfs_create, 740 .lookup = simple_lookup, 741 .link = simple_link, 742 .unlink = simple_unlink, 743 .symlink = hugetlbfs_symlink, 744 .mkdir = hugetlbfs_mkdir, 745 .rmdir = simple_rmdir, 746 .mknod = hugetlbfs_mknod, 747 .rename = simple_rename, 748 .setattr = hugetlbfs_setattr, 749 }; 750 751 static const struct inode_operations hugetlbfs_inode_operations = { 752 .setattr = hugetlbfs_setattr, 753 }; 754 755 static const struct super_operations hugetlbfs_ops = { 756 .alloc_inode = hugetlbfs_alloc_inode, 757 .destroy_inode = hugetlbfs_destroy_inode, 758 .evict_inode = hugetlbfs_evict_inode, 759 .statfs = hugetlbfs_statfs, 760 .put_super = hugetlbfs_put_super, 761 .show_options = generic_show_options, 762 }; 763 764 static int 765 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig) 766 { 767 char *p, *rest; 768 substring_t args[MAX_OPT_ARGS]; 769 int option; 770 unsigned long long size = 0; 771 enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE; 772 773 if (!options) 774 return 0; 775 776 while ((p = strsep(&options, ",")) != NULL) { 777 int token; 778 if (!*p) 779 continue; 780 781 token = match_token(p, tokens, args); 782 switch (token) { 783 case Opt_uid: 784 if (match_int(&args[0], &option)) 785 goto bad_val; 786 pconfig->uid = make_kuid(current_user_ns(), option); 787 if (!uid_valid(pconfig->uid)) 788 goto bad_val; 789 break; 790 791 case Opt_gid: 792 if (match_int(&args[0], &option)) 793 goto bad_val; 794 pconfig->gid = make_kgid(current_user_ns(), option); 795 if (!gid_valid(pconfig->gid)) 796 goto bad_val; 797 break; 798 799 case Opt_mode: 800 if (match_octal(&args[0], &option)) 801 goto bad_val; 802 pconfig->mode = option & 01777U; 803 break; 804 805 case Opt_size: { 806 /* memparse() will accept a K/M/G without a digit */ 807 if (!isdigit(*args[0].from)) 808 goto bad_val; 809 size = memparse(args[0].from, &rest); 810 setsize = SIZE_STD; 811 if (*rest == '%') 812 setsize = SIZE_PERCENT; 813 break; 814 } 815 816 case Opt_nr_inodes: 817 /* memparse() will accept a K/M/G without a digit */ 818 if (!isdigit(*args[0].from)) 819 goto bad_val; 820 pconfig->nr_inodes = memparse(args[0].from, &rest); 821 break; 822 823 case Opt_pagesize: { 824 unsigned long ps; 825 ps = memparse(args[0].from, &rest); 826 pconfig->hstate = size_to_hstate(ps); 827 if (!pconfig->hstate) { 828 pr_err("Unsupported page size %lu MB\n", 829 ps >> 20); 830 return -EINVAL; 831 } 832 break; 833 } 834 835 default: 836 pr_err("Bad mount option: \"%s\"\n", p); 837 return -EINVAL; 838 break; 839 } 840 } 841 842 /* Do size after hstate is set up */ 843 if (setsize > NO_SIZE) { 844 struct hstate *h = pconfig->hstate; 845 if (setsize == SIZE_PERCENT) { 846 size <<= huge_page_shift(h); 847 size *= h->max_huge_pages; 848 do_div(size, 100); 849 } 850 pconfig->nr_blocks = (size >> huge_page_shift(h)); 851 } 852 853 return 0; 854 855 bad_val: 856 pr_err("Bad value '%s' for mount option '%s'\n", args[0].from, p); 857 return -EINVAL; 858 } 859 860 static int 861 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent) 862 { 863 int ret; 864 struct hugetlbfs_config config; 865 struct hugetlbfs_sb_info *sbinfo; 866 867 save_mount_options(sb, data); 868 869 config.nr_blocks = -1; /* No limit on size by default */ 870 config.nr_inodes = -1; /* No limit on number of inodes by default */ 871 config.uid = current_fsuid(); 872 config.gid = current_fsgid(); 873 config.mode = 0755; 874 config.hstate = &default_hstate; 875 ret = hugetlbfs_parse_options(data, &config); 876 if (ret) 877 return ret; 878 879 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL); 880 if (!sbinfo) 881 return -ENOMEM; 882 sb->s_fs_info = sbinfo; 883 sbinfo->hstate = config.hstate; 884 spin_lock_init(&sbinfo->stat_lock); 885 sbinfo->max_inodes = config.nr_inodes; 886 sbinfo->free_inodes = config.nr_inodes; 887 sbinfo->spool = NULL; 888 if (config.nr_blocks != -1) { 889 sbinfo->spool = hugepage_new_subpool(config.nr_blocks); 890 if (!sbinfo->spool) 891 goto out_free; 892 } 893 sb->s_maxbytes = MAX_LFS_FILESIZE; 894 sb->s_blocksize = huge_page_size(config.hstate); 895 sb->s_blocksize_bits = huge_page_shift(config.hstate); 896 sb->s_magic = HUGETLBFS_MAGIC; 897 sb->s_op = &hugetlbfs_ops; 898 sb->s_time_gran = 1; 899 sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config)); 900 if (!sb->s_root) 901 goto out_free; 902 return 0; 903 out_free: 904 kfree(sbinfo->spool); 905 kfree(sbinfo); 906 return -ENOMEM; 907 } 908 909 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type, 910 int flags, const char *dev_name, void *data) 911 { 912 return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super); 913 } 914 915 static struct file_system_type hugetlbfs_fs_type = { 916 .name = "hugetlbfs", 917 .mount = hugetlbfs_mount, 918 .kill_sb = kill_litter_super, 919 }; 920 MODULE_ALIAS_FS("hugetlbfs"); 921 922 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE]; 923 924 static int can_do_hugetlb_shm(void) 925 { 926 kgid_t shm_group; 927 shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group); 928 return capable(CAP_IPC_LOCK) || in_group_p(shm_group); 929 } 930 931 static int get_hstate_idx(int page_size_log) 932 { 933 struct hstate *h = hstate_sizelog(page_size_log); 934 935 if (!h) 936 return -1; 937 return h - hstates; 938 } 939 940 static const struct dentry_operations anon_ops = { 941 .d_dname = simple_dname 942 }; 943 944 /* 945 * Note that size should be aligned to proper hugepage size in caller side, 946 * otherwise hugetlb_reserve_pages reserves one less hugepages than intended. 947 */ 948 struct file *hugetlb_file_setup(const char *name, size_t size, 949 vm_flags_t acctflag, struct user_struct **user, 950 int creat_flags, int page_size_log) 951 { 952 struct file *file = ERR_PTR(-ENOMEM); 953 struct inode *inode; 954 struct path path; 955 struct super_block *sb; 956 struct qstr quick_string; 957 int hstate_idx; 958 959 hstate_idx = get_hstate_idx(page_size_log); 960 if (hstate_idx < 0) 961 return ERR_PTR(-ENODEV); 962 963 *user = NULL; 964 if (!hugetlbfs_vfsmount[hstate_idx]) 965 return ERR_PTR(-ENOENT); 966 967 if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) { 968 *user = current_user(); 969 if (user_shm_lock(size, *user)) { 970 task_lock(current); 971 pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n", 972 current->comm, current->pid); 973 task_unlock(current); 974 } else { 975 *user = NULL; 976 return ERR_PTR(-EPERM); 977 } 978 } 979 980 sb = hugetlbfs_vfsmount[hstate_idx]->mnt_sb; 981 quick_string.name = name; 982 quick_string.len = strlen(quick_string.name); 983 quick_string.hash = 0; 984 path.dentry = d_alloc_pseudo(sb, &quick_string); 985 if (!path.dentry) 986 goto out_shm_unlock; 987 988 d_set_d_op(path.dentry, &anon_ops); 989 path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]); 990 file = ERR_PTR(-ENOSPC); 991 inode = hugetlbfs_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0); 992 if (!inode) 993 goto out_dentry; 994 995 file = ERR_PTR(-ENOMEM); 996 if (hugetlb_reserve_pages(inode, 0, 997 size >> huge_page_shift(hstate_inode(inode)), NULL, 998 acctflag)) 999 goto out_inode; 1000 1001 d_instantiate(path.dentry, inode); 1002 inode->i_size = size; 1003 clear_nlink(inode); 1004 1005 file = alloc_file(&path, FMODE_WRITE | FMODE_READ, 1006 &hugetlbfs_file_operations); 1007 if (IS_ERR(file)) 1008 goto out_dentry; /* inode is already attached */ 1009 1010 return file; 1011 1012 out_inode: 1013 iput(inode); 1014 out_dentry: 1015 path_put(&path); 1016 out_shm_unlock: 1017 if (*user) { 1018 user_shm_unlock(size, *user); 1019 *user = NULL; 1020 } 1021 return file; 1022 } 1023 1024 static int __init init_hugetlbfs_fs(void) 1025 { 1026 struct hstate *h; 1027 int error; 1028 int i; 1029 1030 if (!hugepages_supported()) { 1031 pr_info("disabling because there are no supported hugepage sizes\n"); 1032 return -ENOTSUPP; 1033 } 1034 1035 error = bdi_init(&hugetlbfs_backing_dev_info); 1036 if (error) 1037 return error; 1038 1039 error = -ENOMEM; 1040 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache", 1041 sizeof(struct hugetlbfs_inode_info), 1042 0, 0, init_once); 1043 if (hugetlbfs_inode_cachep == NULL) 1044 goto out2; 1045 1046 error = register_filesystem(&hugetlbfs_fs_type); 1047 if (error) 1048 goto out; 1049 1050 i = 0; 1051 for_each_hstate(h) { 1052 char buf[50]; 1053 unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10); 1054 1055 snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb); 1056 hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type, 1057 buf); 1058 1059 if (IS_ERR(hugetlbfs_vfsmount[i])) { 1060 pr_err("Cannot mount internal hugetlbfs for " 1061 "page size %uK", ps_kb); 1062 error = PTR_ERR(hugetlbfs_vfsmount[i]); 1063 hugetlbfs_vfsmount[i] = NULL; 1064 } 1065 i++; 1066 } 1067 /* Non default hstates are optional */ 1068 if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx])) 1069 return 0; 1070 1071 out: 1072 kmem_cache_destroy(hugetlbfs_inode_cachep); 1073 out2: 1074 bdi_destroy(&hugetlbfs_backing_dev_info); 1075 return error; 1076 } 1077 1078 static void __exit exit_hugetlbfs_fs(void) 1079 { 1080 struct hstate *h; 1081 int i; 1082 1083 1084 /* 1085 * Make sure all delayed rcu free inodes are flushed before we 1086 * destroy cache. 1087 */ 1088 rcu_barrier(); 1089 kmem_cache_destroy(hugetlbfs_inode_cachep); 1090 i = 0; 1091 for_each_hstate(h) 1092 kern_unmount(hugetlbfs_vfsmount[i++]); 1093 unregister_filesystem(&hugetlbfs_fs_type); 1094 bdi_destroy(&hugetlbfs_backing_dev_info); 1095 } 1096 1097 module_init(init_hugetlbfs_fs) 1098 module_exit(exit_hugetlbfs_fs) 1099 1100 MODULE_LICENSE("GPL"); 1101