1 /* 2 * hugetlbpage-backed filesystem. Based on ramfs. 3 * 4 * Nadia Yvette Chambers, 2002 5 * 6 * Copyright (C) 2002 Linus Torvalds. 7 */ 8 9 #include <linux/module.h> 10 #include <linux/thread_info.h> 11 #include <asm/current.h> 12 #include <linux/sched.h> /* remove ASAP */ 13 #include <linux/fs.h> 14 #include <linux/mount.h> 15 #include <linux/file.h> 16 #include <linux/kernel.h> 17 #include <linux/writeback.h> 18 #include <linux/pagemap.h> 19 #include <linux/highmem.h> 20 #include <linux/init.h> 21 #include <linux/string.h> 22 #include <linux/capability.h> 23 #include <linux/ctype.h> 24 #include <linux/backing-dev.h> 25 #include <linux/hugetlb.h> 26 #include <linux/pagevec.h> 27 #include <linux/parser.h> 28 #include <linux/mman.h> 29 #include <linux/slab.h> 30 #include <linux/dnotify.h> 31 #include <linux/statfs.h> 32 #include <linux/security.h> 33 #include <linux/magic.h> 34 #include <linux/migrate.h> 35 36 #include <asm/uaccess.h> 37 38 static const struct super_operations hugetlbfs_ops; 39 static const struct address_space_operations hugetlbfs_aops; 40 const struct file_operations hugetlbfs_file_operations; 41 static const struct inode_operations hugetlbfs_dir_inode_operations; 42 static const struct inode_operations hugetlbfs_inode_operations; 43 44 struct hugetlbfs_config { 45 kuid_t uid; 46 kgid_t gid; 47 umode_t mode; 48 long nr_blocks; 49 long nr_inodes; 50 struct hstate *hstate; 51 }; 52 53 struct hugetlbfs_inode_info { 54 struct shared_policy policy; 55 struct inode vfs_inode; 56 }; 57 58 static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode) 59 { 60 return container_of(inode, struct hugetlbfs_inode_info, vfs_inode); 61 } 62 63 static struct backing_dev_info hugetlbfs_backing_dev_info = { 64 .name = "hugetlbfs", 65 .ra_pages = 0, /* No readahead */ 66 .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, 67 }; 68 69 int sysctl_hugetlb_shm_group; 70 71 enum { 72 Opt_size, Opt_nr_inodes, 73 Opt_mode, Opt_uid, Opt_gid, 74 Opt_pagesize, 75 Opt_err, 76 }; 77 78 static const match_table_t tokens = { 79 {Opt_size, "size=%s"}, 80 {Opt_nr_inodes, "nr_inodes=%s"}, 81 {Opt_mode, "mode=%o"}, 82 {Opt_uid, "uid=%u"}, 83 {Opt_gid, "gid=%u"}, 84 {Opt_pagesize, "pagesize=%s"}, 85 {Opt_err, NULL}, 86 }; 87 88 static void huge_pagevec_release(struct pagevec *pvec) 89 { 90 int i; 91 92 for (i = 0; i < pagevec_count(pvec); ++i) 93 put_page(pvec->pages[i]); 94 95 pagevec_reinit(pvec); 96 } 97 98 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma) 99 { 100 struct inode *inode = file_inode(file); 101 loff_t len, vma_len; 102 int ret; 103 struct hstate *h = hstate_file(file); 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_pgoff unwinds (may be important on powerpc 111 * and ia64). 112 */ 113 vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND; 114 vma->vm_ops = &hugetlb_vm_ops; 115 116 if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT)) 117 return -EINVAL; 118 119 vma_len = (loff_t)(vma->vm_end - vma->vm_start); 120 121 mutex_lock(&inode->i_mutex); 122 file_accessed(file); 123 124 ret = -ENOMEM; 125 len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); 126 127 if (hugetlb_reserve_pages(inode, 128 vma->vm_pgoff >> huge_page_order(h), 129 len >> huge_page_shift(h), vma, 130 vma->vm_flags)) 131 goto out; 132 133 ret = 0; 134 hugetlb_prefault_arch_hook(vma->vm_mm); 135 if (vma->vm_flags & VM_WRITE && inode->i_size < len) 136 inode->i_size = len; 137 out: 138 mutex_unlock(&inode->i_mutex); 139 140 return ret; 141 } 142 143 /* 144 * Called under down_write(mmap_sem). 145 */ 146 147 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA 148 static unsigned long 149 hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 150 unsigned long len, unsigned long pgoff, unsigned long flags) 151 { 152 struct mm_struct *mm = current->mm; 153 struct vm_area_struct *vma; 154 struct hstate *h = hstate_file(file); 155 struct vm_unmapped_area_info info; 156 157 if (len & ~huge_page_mask(h)) 158 return -EINVAL; 159 if (len > TASK_SIZE) 160 return -ENOMEM; 161 162 if (flags & MAP_FIXED) { 163 if (prepare_hugepage_range(file, addr, len)) 164 return -EINVAL; 165 return addr; 166 } 167 168 if (addr) { 169 addr = ALIGN(addr, huge_page_size(h)); 170 vma = find_vma(mm, addr); 171 if (TASK_SIZE - len >= addr && 172 (!vma || addr + len <= vma->vm_start)) 173 return addr; 174 } 175 176 info.flags = 0; 177 info.length = len; 178 info.low_limit = TASK_UNMAPPED_BASE; 179 info.high_limit = TASK_SIZE; 180 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 181 info.align_offset = 0; 182 return vm_unmapped_area(&info); 183 } 184 #endif 185 186 static int 187 hugetlbfs_read_actor(struct page *page, unsigned long offset, 188 char __user *buf, unsigned long count, 189 unsigned long size) 190 { 191 char *kaddr; 192 unsigned long left, copied = 0; 193 int i, chunksize; 194 195 if (size > count) 196 size = count; 197 198 /* Find which 4k chunk and offset with in that chunk */ 199 i = offset >> PAGE_CACHE_SHIFT; 200 offset = offset & ~PAGE_CACHE_MASK; 201 202 while (size) { 203 chunksize = PAGE_CACHE_SIZE; 204 if (offset) 205 chunksize -= offset; 206 if (chunksize > size) 207 chunksize = size; 208 kaddr = kmap(&page[i]); 209 left = __copy_to_user(buf, kaddr + offset, chunksize); 210 kunmap(&page[i]); 211 if (left) { 212 copied += (chunksize - left); 213 break; 214 } 215 offset = 0; 216 size -= chunksize; 217 buf += chunksize; 218 copied += chunksize; 219 i++; 220 } 221 return copied ? copied : -EFAULT; 222 } 223 224 /* 225 * Support for read() - Find the page attached to f_mapping and copy out the 226 * data. Its *very* similar to do_generic_mapping_read(), we can't use that 227 * since it has PAGE_CACHE_SIZE assumptions. 228 */ 229 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf, 230 size_t len, loff_t *ppos) 231 { 232 struct hstate *h = hstate_file(filp); 233 struct address_space *mapping = filp->f_mapping; 234 struct inode *inode = mapping->host; 235 unsigned long index = *ppos >> huge_page_shift(h); 236 unsigned long offset = *ppos & ~huge_page_mask(h); 237 unsigned long end_index; 238 loff_t isize; 239 ssize_t retval = 0; 240 241 /* validate length */ 242 if (len == 0) 243 goto out; 244 245 for (;;) { 246 struct page *page; 247 unsigned long nr, ret; 248 int ra; 249 250 /* nr is the maximum number of bytes to copy from this page */ 251 nr = huge_page_size(h); 252 isize = i_size_read(inode); 253 if (!isize) 254 goto out; 255 end_index = (isize - 1) >> huge_page_shift(h); 256 if (index >= end_index) { 257 if (index > end_index) 258 goto out; 259 nr = ((isize - 1) & ~huge_page_mask(h)) + 1; 260 if (nr <= offset) 261 goto out; 262 } 263 nr = nr - offset; 264 265 /* Find the page */ 266 page = find_lock_page(mapping, index); 267 if (unlikely(page == NULL)) { 268 /* 269 * We have a HOLE, zero out the user-buffer for the 270 * length of the hole or request. 271 */ 272 ret = len < nr ? len : nr; 273 if (clear_user(buf, ret)) 274 ra = -EFAULT; 275 else 276 ra = 0; 277 } else { 278 unlock_page(page); 279 280 /* 281 * We have the page, copy it to user space buffer. 282 */ 283 ra = hugetlbfs_read_actor(page, offset, buf, len, nr); 284 ret = ra; 285 page_cache_release(page); 286 } 287 if (ra < 0) { 288 if (retval == 0) 289 retval = ra; 290 goto out; 291 } 292 293 offset += ret; 294 retval += ret; 295 len -= ret; 296 index += offset >> huge_page_shift(h); 297 offset &= ~huge_page_mask(h); 298 299 /* short read or no more work */ 300 if ((ret != nr) || (len == 0)) 301 break; 302 } 303 out: 304 *ppos = ((loff_t)index << huge_page_shift(h)) + offset; 305 return retval; 306 } 307 308 static int hugetlbfs_write_begin(struct file *file, 309 struct address_space *mapping, 310 loff_t pos, unsigned len, unsigned flags, 311 struct page **pagep, void **fsdata) 312 { 313 return -EINVAL; 314 } 315 316 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping, 317 loff_t pos, unsigned len, unsigned copied, 318 struct page *page, void *fsdata) 319 { 320 BUG(); 321 return -EINVAL; 322 } 323 324 static void truncate_huge_page(struct page *page) 325 { 326 cancel_dirty_page(page, /* No IO accounting for huge pages? */0); 327 ClearPageUptodate(page); 328 delete_from_page_cache(page); 329 } 330 331 static void truncate_hugepages(struct inode *inode, loff_t lstart) 332 { 333 struct hstate *h = hstate_inode(inode); 334 struct address_space *mapping = &inode->i_data; 335 const pgoff_t start = lstart >> huge_page_shift(h); 336 struct pagevec pvec; 337 pgoff_t next; 338 int i, freed = 0; 339 340 pagevec_init(&pvec, 0); 341 next = start; 342 while (1) { 343 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { 344 if (next == start) 345 break; 346 next = start; 347 continue; 348 } 349 350 for (i = 0; i < pagevec_count(&pvec); ++i) { 351 struct page *page = pvec.pages[i]; 352 353 lock_page(page); 354 if (page->index > next) 355 next = page->index; 356 ++next; 357 truncate_huge_page(page); 358 unlock_page(page); 359 freed++; 360 } 361 huge_pagevec_release(&pvec); 362 } 363 BUG_ON(!lstart && mapping->nrpages); 364 hugetlb_unreserve_pages(inode, start, freed); 365 } 366 367 static void hugetlbfs_evict_inode(struct inode *inode) 368 { 369 struct resv_map *resv_map; 370 371 truncate_hugepages(inode, 0); 372 resv_map = (struct resv_map *)inode->i_mapping->private_data; 373 /* root inode doesn't have the resv_map, so we should check it */ 374 if (resv_map) 375 resv_map_release(&resv_map->refs); 376 clear_inode(inode); 377 } 378 379 static inline void 380 hugetlb_vmtruncate_list(struct rb_root *root, pgoff_t pgoff) 381 { 382 struct vm_area_struct *vma; 383 384 vma_interval_tree_foreach(vma, root, pgoff, ULONG_MAX) { 385 unsigned long v_offset; 386 387 /* 388 * Can the expression below overflow on 32-bit arches? 389 * No, because the interval tree returns us only those vmas 390 * which overlap the truncated area starting at pgoff, 391 * and no vma on a 32-bit arch can span beyond the 4GB. 392 */ 393 if (vma->vm_pgoff < pgoff) 394 v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT; 395 else 396 v_offset = 0; 397 398 unmap_hugepage_range(vma, vma->vm_start + v_offset, 399 vma->vm_end, NULL); 400 } 401 } 402 403 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset) 404 { 405 pgoff_t pgoff; 406 struct address_space *mapping = inode->i_mapping; 407 struct hstate *h = hstate_inode(inode); 408 409 BUG_ON(offset & ~huge_page_mask(h)); 410 pgoff = offset >> PAGE_SHIFT; 411 412 i_size_write(inode, offset); 413 mutex_lock(&mapping->i_mmap_mutex); 414 if (!RB_EMPTY_ROOT(&mapping->i_mmap)) 415 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff); 416 mutex_unlock(&mapping->i_mmap_mutex); 417 truncate_hugepages(inode, offset); 418 return 0; 419 } 420 421 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr) 422 { 423 struct inode *inode = dentry->d_inode; 424 struct hstate *h = hstate_inode(inode); 425 int error; 426 unsigned int ia_valid = attr->ia_valid; 427 428 BUG_ON(!inode); 429 430 error = inode_change_ok(inode, attr); 431 if (error) 432 return error; 433 434 if (ia_valid & ATTR_SIZE) { 435 error = -EINVAL; 436 if (attr->ia_size & ~huge_page_mask(h)) 437 return -EINVAL; 438 error = hugetlb_vmtruncate(inode, attr->ia_size); 439 if (error) 440 return error; 441 } 442 443 setattr_copy(inode, attr); 444 mark_inode_dirty(inode); 445 return 0; 446 } 447 448 static struct inode *hugetlbfs_get_root(struct super_block *sb, 449 struct hugetlbfs_config *config) 450 { 451 struct inode *inode; 452 453 inode = new_inode(sb); 454 if (inode) { 455 struct hugetlbfs_inode_info *info; 456 inode->i_ino = get_next_ino(); 457 inode->i_mode = S_IFDIR | config->mode; 458 inode->i_uid = config->uid; 459 inode->i_gid = config->gid; 460 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 461 info = HUGETLBFS_I(inode); 462 mpol_shared_policy_init(&info->policy, NULL); 463 inode->i_op = &hugetlbfs_dir_inode_operations; 464 inode->i_fop = &simple_dir_operations; 465 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 466 inc_nlink(inode); 467 lockdep_annotate_inode_mutex_key(inode); 468 } 469 return inode; 470 } 471 472 /* 473 * Hugetlbfs is not reclaimable; therefore its i_mmap_mutex will never 474 * be taken from reclaim -- unlike regular filesystems. This needs an 475 * annotation because huge_pmd_share() does an allocation under 476 * i_mmap_mutex. 477 */ 478 struct lock_class_key hugetlbfs_i_mmap_mutex_key; 479 480 static struct inode *hugetlbfs_get_inode(struct super_block *sb, 481 struct inode *dir, 482 umode_t mode, dev_t dev) 483 { 484 struct inode *inode; 485 struct resv_map *resv_map; 486 487 resv_map = resv_map_alloc(); 488 if (!resv_map) 489 return NULL; 490 491 inode = new_inode(sb); 492 if (inode) { 493 struct hugetlbfs_inode_info *info; 494 inode->i_ino = get_next_ino(); 495 inode_init_owner(inode, dir, mode); 496 lockdep_set_class(&inode->i_mapping->i_mmap_mutex, 497 &hugetlbfs_i_mmap_mutex_key); 498 inode->i_mapping->a_ops = &hugetlbfs_aops; 499 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info; 500 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 501 inode->i_mapping->private_data = resv_map; 502 info = HUGETLBFS_I(inode); 503 /* 504 * The policy is initialized here even if we are creating a 505 * private inode because initialization simply creates an 506 * an empty rb tree and calls spin_lock_init(), later when we 507 * call mpol_free_shared_policy() it will just return because 508 * the rb tree will still be empty. 509 */ 510 mpol_shared_policy_init(&info->policy, NULL); 511 switch (mode & S_IFMT) { 512 default: 513 init_special_inode(inode, mode, dev); 514 break; 515 case S_IFREG: 516 inode->i_op = &hugetlbfs_inode_operations; 517 inode->i_fop = &hugetlbfs_file_operations; 518 break; 519 case S_IFDIR: 520 inode->i_op = &hugetlbfs_dir_inode_operations; 521 inode->i_fop = &simple_dir_operations; 522 523 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 524 inc_nlink(inode); 525 break; 526 case S_IFLNK: 527 inode->i_op = &page_symlink_inode_operations; 528 break; 529 } 530 lockdep_annotate_inode_mutex_key(inode); 531 } else 532 kref_put(&resv_map->refs, resv_map_release); 533 534 return inode; 535 } 536 537 /* 538 * File creation. Allocate an inode, and we're done.. 539 */ 540 static int hugetlbfs_mknod(struct inode *dir, 541 struct dentry *dentry, umode_t mode, dev_t dev) 542 { 543 struct inode *inode; 544 int error = -ENOSPC; 545 546 inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev); 547 if (inode) { 548 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 549 d_instantiate(dentry, inode); 550 dget(dentry); /* Extra count - pin the dentry in core */ 551 error = 0; 552 } 553 return error; 554 } 555 556 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 557 { 558 int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0); 559 if (!retval) 560 inc_nlink(dir); 561 return retval; 562 } 563 564 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) 565 { 566 return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0); 567 } 568 569 static int hugetlbfs_symlink(struct inode *dir, 570 struct dentry *dentry, const char *symname) 571 { 572 struct inode *inode; 573 int error = -ENOSPC; 574 575 inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0); 576 if (inode) { 577 int l = strlen(symname)+1; 578 error = page_symlink(inode, symname, l); 579 if (!error) { 580 d_instantiate(dentry, inode); 581 dget(dentry); 582 } else 583 iput(inode); 584 } 585 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 586 587 return error; 588 } 589 590 /* 591 * mark the head page dirty 592 */ 593 static int hugetlbfs_set_page_dirty(struct page *page) 594 { 595 struct page *head = compound_head(page); 596 597 SetPageDirty(head); 598 return 0; 599 } 600 601 static int hugetlbfs_migrate_page(struct address_space *mapping, 602 struct page *newpage, struct page *page, 603 enum migrate_mode mode) 604 { 605 int rc; 606 607 rc = migrate_huge_page_move_mapping(mapping, newpage, page); 608 if (rc != MIGRATEPAGE_SUCCESS) 609 return rc; 610 migrate_page_copy(newpage, page); 611 612 return MIGRATEPAGE_SUCCESS; 613 } 614 615 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf) 616 { 617 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb); 618 struct hstate *h = hstate_inode(dentry->d_inode); 619 620 buf->f_type = HUGETLBFS_MAGIC; 621 buf->f_bsize = huge_page_size(h); 622 if (sbinfo) { 623 spin_lock(&sbinfo->stat_lock); 624 /* If no limits set, just report 0 for max/free/used 625 * blocks, like simple_statfs() */ 626 if (sbinfo->spool) { 627 long free_pages; 628 629 spin_lock(&sbinfo->spool->lock); 630 buf->f_blocks = sbinfo->spool->max_hpages; 631 free_pages = sbinfo->spool->max_hpages 632 - sbinfo->spool->used_hpages; 633 buf->f_bavail = buf->f_bfree = free_pages; 634 spin_unlock(&sbinfo->spool->lock); 635 buf->f_files = sbinfo->max_inodes; 636 buf->f_ffree = sbinfo->free_inodes; 637 } 638 spin_unlock(&sbinfo->stat_lock); 639 } 640 buf->f_namelen = NAME_MAX; 641 return 0; 642 } 643 644 static void hugetlbfs_put_super(struct super_block *sb) 645 { 646 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb); 647 648 if (sbi) { 649 sb->s_fs_info = NULL; 650 651 if (sbi->spool) 652 hugepage_put_subpool(sbi->spool); 653 654 kfree(sbi); 655 } 656 } 657 658 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo) 659 { 660 if (sbinfo->free_inodes >= 0) { 661 spin_lock(&sbinfo->stat_lock); 662 if (unlikely(!sbinfo->free_inodes)) { 663 spin_unlock(&sbinfo->stat_lock); 664 return 0; 665 } 666 sbinfo->free_inodes--; 667 spin_unlock(&sbinfo->stat_lock); 668 } 669 670 return 1; 671 } 672 673 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo) 674 { 675 if (sbinfo->free_inodes >= 0) { 676 spin_lock(&sbinfo->stat_lock); 677 sbinfo->free_inodes++; 678 spin_unlock(&sbinfo->stat_lock); 679 } 680 } 681 682 683 static struct kmem_cache *hugetlbfs_inode_cachep; 684 685 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb) 686 { 687 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb); 688 struct hugetlbfs_inode_info *p; 689 690 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo))) 691 return NULL; 692 p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL); 693 if (unlikely(!p)) { 694 hugetlbfs_inc_free_inodes(sbinfo); 695 return NULL; 696 } 697 return &p->vfs_inode; 698 } 699 700 static void hugetlbfs_i_callback(struct rcu_head *head) 701 { 702 struct inode *inode = container_of(head, struct inode, i_rcu); 703 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode)); 704 } 705 706 static void hugetlbfs_destroy_inode(struct inode *inode) 707 { 708 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb)); 709 mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy); 710 call_rcu(&inode->i_rcu, hugetlbfs_i_callback); 711 } 712 713 static const struct address_space_operations hugetlbfs_aops = { 714 .write_begin = hugetlbfs_write_begin, 715 .write_end = hugetlbfs_write_end, 716 .set_page_dirty = hugetlbfs_set_page_dirty, 717 .migratepage = hugetlbfs_migrate_page, 718 }; 719 720 721 static void init_once(void *foo) 722 { 723 struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo; 724 725 inode_init_once(&ei->vfs_inode); 726 } 727 728 const struct file_operations hugetlbfs_file_operations = { 729 .read = hugetlbfs_read, 730 .mmap = hugetlbfs_file_mmap, 731 .fsync = noop_fsync, 732 .get_unmapped_area = hugetlb_get_unmapped_area, 733 .llseek = default_llseek, 734 }; 735 736 static const struct inode_operations hugetlbfs_dir_inode_operations = { 737 .create = hugetlbfs_create, 738 .lookup = simple_lookup, 739 .link = simple_link, 740 .unlink = simple_unlink, 741 .symlink = hugetlbfs_symlink, 742 .mkdir = hugetlbfs_mkdir, 743 .rmdir = simple_rmdir, 744 .mknod = hugetlbfs_mknod, 745 .rename = simple_rename, 746 .setattr = hugetlbfs_setattr, 747 }; 748 749 static const struct inode_operations hugetlbfs_inode_operations = { 750 .setattr = hugetlbfs_setattr, 751 }; 752 753 static const struct super_operations hugetlbfs_ops = { 754 .alloc_inode = hugetlbfs_alloc_inode, 755 .destroy_inode = hugetlbfs_destroy_inode, 756 .evict_inode = hugetlbfs_evict_inode, 757 .statfs = hugetlbfs_statfs, 758 .put_super = hugetlbfs_put_super, 759 .show_options = generic_show_options, 760 }; 761 762 static int 763 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig) 764 { 765 char *p, *rest; 766 substring_t args[MAX_OPT_ARGS]; 767 int option; 768 unsigned long long size = 0; 769 enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE; 770 771 if (!options) 772 return 0; 773 774 while ((p = strsep(&options, ",")) != NULL) { 775 int token; 776 if (!*p) 777 continue; 778 779 token = match_token(p, tokens, args); 780 switch (token) { 781 case Opt_uid: 782 if (match_int(&args[0], &option)) 783 goto bad_val; 784 pconfig->uid = make_kuid(current_user_ns(), option); 785 if (!uid_valid(pconfig->uid)) 786 goto bad_val; 787 break; 788 789 case Opt_gid: 790 if (match_int(&args[0], &option)) 791 goto bad_val; 792 pconfig->gid = make_kgid(current_user_ns(), option); 793 if (!gid_valid(pconfig->gid)) 794 goto bad_val; 795 break; 796 797 case Opt_mode: 798 if (match_octal(&args[0], &option)) 799 goto bad_val; 800 pconfig->mode = option & 01777U; 801 break; 802 803 case Opt_size: { 804 /* memparse() will accept a K/M/G without a digit */ 805 if (!isdigit(*args[0].from)) 806 goto bad_val; 807 size = memparse(args[0].from, &rest); 808 setsize = SIZE_STD; 809 if (*rest == '%') 810 setsize = SIZE_PERCENT; 811 break; 812 } 813 814 case Opt_nr_inodes: 815 /* memparse() will accept a K/M/G without a digit */ 816 if (!isdigit(*args[0].from)) 817 goto bad_val; 818 pconfig->nr_inodes = memparse(args[0].from, &rest); 819 break; 820 821 case Opt_pagesize: { 822 unsigned long ps; 823 ps = memparse(args[0].from, &rest); 824 pconfig->hstate = size_to_hstate(ps); 825 if (!pconfig->hstate) { 826 printk(KERN_ERR 827 "hugetlbfs: Unsupported page size %lu MB\n", 828 ps >> 20); 829 return -EINVAL; 830 } 831 break; 832 } 833 834 default: 835 printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n", 836 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 printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n", 857 args[0].from, p); 858 return -EINVAL; 859 } 860 861 static int 862 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent) 863 { 864 int ret; 865 struct hugetlbfs_config config; 866 struct hugetlbfs_sb_info *sbinfo; 867 868 save_mount_options(sb, data); 869 870 config.nr_blocks = -1; /* No limit on size by default */ 871 config.nr_inodes = -1; /* No limit on number of inodes by default */ 872 config.uid = current_fsuid(); 873 config.gid = current_fsgid(); 874 config.mode = 0755; 875 config.hstate = &default_hstate; 876 ret = hugetlbfs_parse_options(data, &config); 877 if (ret) 878 return ret; 879 880 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL); 881 if (!sbinfo) 882 return -ENOMEM; 883 sb->s_fs_info = sbinfo; 884 sbinfo->hstate = config.hstate; 885 spin_lock_init(&sbinfo->stat_lock); 886 sbinfo->max_inodes = config.nr_inodes; 887 sbinfo->free_inodes = config.nr_inodes; 888 sbinfo->spool = NULL; 889 if (config.nr_blocks != -1) { 890 sbinfo->spool = hugepage_new_subpool(config.nr_blocks); 891 if (!sbinfo->spool) 892 goto out_free; 893 } 894 sb->s_maxbytes = MAX_LFS_FILESIZE; 895 sb->s_blocksize = huge_page_size(config.hstate); 896 sb->s_blocksize_bits = huge_page_shift(config.hstate); 897 sb->s_magic = HUGETLBFS_MAGIC; 898 sb->s_op = &hugetlbfs_ops; 899 sb->s_time_gran = 1; 900 sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config)); 901 if (!sb->s_root) 902 goto out_free; 903 return 0; 904 out_free: 905 if (sbinfo->spool) 906 kfree(sbinfo->spool); 907 kfree(sbinfo); 908 return -ENOMEM; 909 } 910 911 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type, 912 int flags, const char *dev_name, void *data) 913 { 914 return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super); 915 } 916 917 static struct file_system_type hugetlbfs_fs_type = { 918 .name = "hugetlbfs", 919 .mount = hugetlbfs_mount, 920 .kill_sb = kill_litter_super, 921 }; 922 MODULE_ALIAS_FS("hugetlbfs"); 923 924 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE]; 925 926 static int can_do_hugetlb_shm(void) 927 { 928 kgid_t shm_group; 929 shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group); 930 return capable(CAP_IPC_LOCK) || in_group_p(shm_group); 931 } 932 933 static int get_hstate_idx(int page_size_log) 934 { 935 struct hstate *h = hstate_sizelog(page_size_log); 936 937 if (!h) 938 return -1; 939 return h - hstates; 940 } 941 942 static struct dentry_operations anon_ops = { 943 .d_dname = simple_dname 944 }; 945 946 /* 947 * Note that size should be aligned to proper hugepage size in caller side, 948 * otherwise hugetlb_reserve_pages reserves one less hugepages than intended. 949 */ 950 struct file *hugetlb_file_setup(const char *name, size_t size, 951 vm_flags_t acctflag, struct user_struct **user, 952 int creat_flags, int page_size_log) 953 { 954 struct file *file = ERR_PTR(-ENOMEM); 955 struct inode *inode; 956 struct path path; 957 struct super_block *sb; 958 struct qstr quick_string; 959 int hstate_idx; 960 961 hstate_idx = get_hstate_idx(page_size_log); 962 if (hstate_idx < 0) 963 return ERR_PTR(-ENODEV); 964 965 *user = NULL; 966 if (!hugetlbfs_vfsmount[hstate_idx]) 967 return ERR_PTR(-ENOENT); 968 969 if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) { 970 *user = current_user(); 971 if (user_shm_lock(size, *user)) { 972 task_lock(current); 973 printk_once(KERN_WARNING 974 "%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n", 975 current->comm, current->pid); 976 task_unlock(current); 977 } else { 978 *user = NULL; 979 return ERR_PTR(-EPERM); 980 } 981 } 982 983 sb = hugetlbfs_vfsmount[hstate_idx]->mnt_sb; 984 quick_string.name = name; 985 quick_string.len = strlen(quick_string.name); 986 quick_string.hash = 0; 987 path.dentry = d_alloc_pseudo(sb, &quick_string); 988 if (!path.dentry) 989 goto out_shm_unlock; 990 991 d_set_d_op(path.dentry, &anon_ops); 992 path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]); 993 file = ERR_PTR(-ENOSPC); 994 inode = hugetlbfs_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0); 995 if (!inode) 996 goto out_dentry; 997 998 file = ERR_PTR(-ENOMEM); 999 if (hugetlb_reserve_pages(inode, 0, 1000 size >> huge_page_shift(hstate_inode(inode)), NULL, 1001 acctflag)) 1002 goto out_inode; 1003 1004 d_instantiate(path.dentry, inode); 1005 inode->i_size = size; 1006 clear_nlink(inode); 1007 1008 file = alloc_file(&path, FMODE_WRITE | FMODE_READ, 1009 &hugetlbfs_file_operations); 1010 if (IS_ERR(file)) 1011 goto out_dentry; /* inode is already attached */ 1012 1013 return file; 1014 1015 out_inode: 1016 iput(inode); 1017 out_dentry: 1018 path_put(&path); 1019 out_shm_unlock: 1020 if (*user) { 1021 user_shm_unlock(size, *user); 1022 *user = NULL; 1023 } 1024 return file; 1025 } 1026 1027 static int __init init_hugetlbfs_fs(void) 1028 { 1029 struct hstate *h; 1030 int error; 1031 int i; 1032 1033 error = bdi_init(&hugetlbfs_backing_dev_info); 1034 if (error) 1035 return error; 1036 1037 error = -ENOMEM; 1038 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache", 1039 sizeof(struct hugetlbfs_inode_info), 1040 0, 0, init_once); 1041 if (hugetlbfs_inode_cachep == NULL) 1042 goto out2; 1043 1044 error = register_filesystem(&hugetlbfs_fs_type); 1045 if (error) 1046 goto out; 1047 1048 i = 0; 1049 for_each_hstate(h) { 1050 char buf[50]; 1051 unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10); 1052 1053 snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb); 1054 hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type, 1055 buf); 1056 1057 if (IS_ERR(hugetlbfs_vfsmount[i])) { 1058 pr_err("hugetlb: Cannot mount internal hugetlbfs for " 1059 "page size %uK", ps_kb); 1060 error = PTR_ERR(hugetlbfs_vfsmount[i]); 1061 hugetlbfs_vfsmount[i] = NULL; 1062 } 1063 i++; 1064 } 1065 /* Non default hstates are optional */ 1066 if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx])) 1067 return 0; 1068 1069 out: 1070 kmem_cache_destroy(hugetlbfs_inode_cachep); 1071 out2: 1072 bdi_destroy(&hugetlbfs_backing_dev_info); 1073 return error; 1074 } 1075 1076 static void __exit exit_hugetlbfs_fs(void) 1077 { 1078 struct hstate *h; 1079 int i; 1080 1081 1082 /* 1083 * Make sure all delayed rcu free inodes are flushed before we 1084 * destroy cache. 1085 */ 1086 rcu_barrier(); 1087 kmem_cache_destroy(hugetlbfs_inode_cachep); 1088 i = 0; 1089 for_each_hstate(h) 1090 kern_unmount(hugetlbfs_vfsmount[i++]); 1091 unregister_filesystem(&hugetlbfs_fs_type); 1092 bdi_destroy(&hugetlbfs_backing_dev_info); 1093 } 1094 1095 module_init(init_hugetlbfs_fs) 1096 module_exit(exit_hugetlbfs_fs) 1097 1098 MODULE_LICENSE("GPL"); 1099