1 /* 2 * hugetlbpage-backed filesystem. Based on ramfs. 3 * 4 * William Irwin, 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 uid_t uid; 46 gid_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->f_path.dentry->d_inode; 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_RESERVED; 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 unsigned long start_addr; 155 struct hstate *h = hstate_file(file); 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 if (len > mm->cached_hole_size) 177 start_addr = mm->free_area_cache; 178 else { 179 start_addr = TASK_UNMAPPED_BASE; 180 mm->cached_hole_size = 0; 181 } 182 183 full_search: 184 addr = ALIGN(start_addr, huge_page_size(h)); 185 186 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { 187 /* At this point: (!vma || addr < vma->vm_end). */ 188 if (TASK_SIZE - len < addr) { 189 /* 190 * Start a new search - just in case we missed 191 * some holes. 192 */ 193 if (start_addr != TASK_UNMAPPED_BASE) { 194 start_addr = TASK_UNMAPPED_BASE; 195 mm->cached_hole_size = 0; 196 goto full_search; 197 } 198 return -ENOMEM; 199 } 200 201 if (!vma || addr + len <= vma->vm_start) { 202 mm->free_area_cache = addr + len; 203 return addr; 204 } 205 if (addr + mm->cached_hole_size < vma->vm_start) 206 mm->cached_hole_size = vma->vm_start - addr; 207 addr = ALIGN(vma->vm_end, huge_page_size(h)); 208 } 209 } 210 #endif 211 212 static int 213 hugetlbfs_read_actor(struct page *page, unsigned long offset, 214 char __user *buf, unsigned long count, 215 unsigned long size) 216 { 217 char *kaddr; 218 unsigned long left, copied = 0; 219 int i, chunksize; 220 221 if (size > count) 222 size = count; 223 224 /* Find which 4k chunk and offset with in that chunk */ 225 i = offset >> PAGE_CACHE_SHIFT; 226 offset = offset & ~PAGE_CACHE_MASK; 227 228 while (size) { 229 chunksize = PAGE_CACHE_SIZE; 230 if (offset) 231 chunksize -= offset; 232 if (chunksize > size) 233 chunksize = size; 234 kaddr = kmap(&page[i]); 235 left = __copy_to_user(buf, kaddr + offset, chunksize); 236 kunmap(&page[i]); 237 if (left) { 238 copied += (chunksize - left); 239 break; 240 } 241 offset = 0; 242 size -= chunksize; 243 buf += chunksize; 244 copied += chunksize; 245 i++; 246 } 247 return copied ? copied : -EFAULT; 248 } 249 250 /* 251 * Support for read() - Find the page attached to f_mapping and copy out the 252 * data. Its *very* similar to do_generic_mapping_read(), we can't use that 253 * since it has PAGE_CACHE_SIZE assumptions. 254 */ 255 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf, 256 size_t len, loff_t *ppos) 257 { 258 struct hstate *h = hstate_file(filp); 259 struct address_space *mapping = filp->f_mapping; 260 struct inode *inode = mapping->host; 261 unsigned long index = *ppos >> huge_page_shift(h); 262 unsigned long offset = *ppos & ~huge_page_mask(h); 263 unsigned long end_index; 264 loff_t isize; 265 ssize_t retval = 0; 266 267 /* validate length */ 268 if (len == 0) 269 goto out; 270 271 for (;;) { 272 struct page *page; 273 unsigned long nr, ret; 274 int ra; 275 276 /* nr is the maximum number of bytes to copy from this page */ 277 nr = huge_page_size(h); 278 isize = i_size_read(inode); 279 if (!isize) 280 goto out; 281 end_index = (isize - 1) >> huge_page_shift(h); 282 if (index >= end_index) { 283 if (index > end_index) 284 goto out; 285 nr = ((isize - 1) & ~huge_page_mask(h)) + 1; 286 if (nr <= offset) 287 goto out; 288 } 289 nr = nr - offset; 290 291 /* Find the page */ 292 page = find_lock_page(mapping, index); 293 if (unlikely(page == NULL)) { 294 /* 295 * We have a HOLE, zero out the user-buffer for the 296 * length of the hole or request. 297 */ 298 ret = len < nr ? len : nr; 299 if (clear_user(buf, ret)) 300 ra = -EFAULT; 301 else 302 ra = 0; 303 } else { 304 unlock_page(page); 305 306 /* 307 * We have the page, copy it to user space buffer. 308 */ 309 ra = hugetlbfs_read_actor(page, offset, buf, len, nr); 310 ret = ra; 311 page_cache_release(page); 312 } 313 if (ra < 0) { 314 if (retval == 0) 315 retval = ra; 316 goto out; 317 } 318 319 offset += ret; 320 retval += ret; 321 len -= ret; 322 index += offset >> huge_page_shift(h); 323 offset &= ~huge_page_mask(h); 324 325 /* short read or no more work */ 326 if ((ret != nr) || (len == 0)) 327 break; 328 } 329 out: 330 *ppos = ((loff_t)index << huge_page_shift(h)) + offset; 331 return retval; 332 } 333 334 static int hugetlbfs_write_begin(struct file *file, 335 struct address_space *mapping, 336 loff_t pos, unsigned len, unsigned flags, 337 struct page **pagep, void **fsdata) 338 { 339 return -EINVAL; 340 } 341 342 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping, 343 loff_t pos, unsigned len, unsigned copied, 344 struct page *page, void *fsdata) 345 { 346 BUG(); 347 return -EINVAL; 348 } 349 350 static void truncate_huge_page(struct page *page) 351 { 352 cancel_dirty_page(page, /* No IO accounting for huge pages? */0); 353 ClearPageUptodate(page); 354 delete_from_page_cache(page); 355 } 356 357 static void truncate_hugepages(struct inode *inode, loff_t lstart) 358 { 359 struct hstate *h = hstate_inode(inode); 360 struct address_space *mapping = &inode->i_data; 361 const pgoff_t start = lstart >> huge_page_shift(h); 362 struct pagevec pvec; 363 pgoff_t next; 364 int i, freed = 0; 365 366 pagevec_init(&pvec, 0); 367 next = start; 368 while (1) { 369 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { 370 if (next == start) 371 break; 372 next = start; 373 continue; 374 } 375 376 for (i = 0; i < pagevec_count(&pvec); ++i) { 377 struct page *page = pvec.pages[i]; 378 379 lock_page(page); 380 if (page->index > next) 381 next = page->index; 382 ++next; 383 truncate_huge_page(page); 384 unlock_page(page); 385 freed++; 386 } 387 huge_pagevec_release(&pvec); 388 } 389 BUG_ON(!lstart && mapping->nrpages); 390 hugetlb_unreserve_pages(inode, start, freed); 391 } 392 393 static void hugetlbfs_evict_inode(struct inode *inode) 394 { 395 truncate_hugepages(inode, 0); 396 clear_inode(inode); 397 } 398 399 static inline void 400 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff) 401 { 402 struct vm_area_struct *vma; 403 struct prio_tree_iter iter; 404 405 vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) { 406 unsigned long v_offset; 407 408 /* 409 * Can the expression below overflow on 32-bit arches? 410 * No, because the prio_tree returns us only those vmas 411 * which overlap the truncated area starting at pgoff, 412 * and no vma on a 32-bit arch can span beyond the 4GB. 413 */ 414 if (vma->vm_pgoff < pgoff) 415 v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT; 416 else 417 v_offset = 0; 418 419 __unmap_hugepage_range(vma, 420 vma->vm_start + v_offset, vma->vm_end, NULL); 421 } 422 } 423 424 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset) 425 { 426 pgoff_t pgoff; 427 struct address_space *mapping = inode->i_mapping; 428 struct hstate *h = hstate_inode(inode); 429 430 BUG_ON(offset & ~huge_page_mask(h)); 431 pgoff = offset >> PAGE_SHIFT; 432 433 i_size_write(inode, offset); 434 mutex_lock(&mapping->i_mmap_mutex); 435 if (!prio_tree_empty(&mapping->i_mmap)) 436 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff); 437 mutex_unlock(&mapping->i_mmap_mutex); 438 truncate_hugepages(inode, offset); 439 return 0; 440 } 441 442 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr) 443 { 444 struct inode *inode = dentry->d_inode; 445 struct hstate *h = hstate_inode(inode); 446 int error; 447 unsigned int ia_valid = attr->ia_valid; 448 449 BUG_ON(!inode); 450 451 error = inode_change_ok(inode, attr); 452 if (error) 453 return error; 454 455 if (ia_valid & ATTR_SIZE) { 456 error = -EINVAL; 457 if (attr->ia_size & ~huge_page_mask(h)) 458 return -EINVAL; 459 error = hugetlb_vmtruncate(inode, attr->ia_size); 460 if (error) 461 return error; 462 } 463 464 setattr_copy(inode, attr); 465 mark_inode_dirty(inode); 466 return 0; 467 } 468 469 static struct inode *hugetlbfs_get_root(struct super_block *sb, 470 struct hugetlbfs_config *config) 471 { 472 struct inode *inode; 473 474 inode = new_inode(sb); 475 if (inode) { 476 struct hugetlbfs_inode_info *info; 477 inode->i_ino = get_next_ino(); 478 inode->i_mode = S_IFDIR | config->mode; 479 inode->i_uid = config->uid; 480 inode->i_gid = config->gid; 481 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 482 info = HUGETLBFS_I(inode); 483 mpol_shared_policy_init(&info->policy, NULL); 484 inode->i_op = &hugetlbfs_dir_inode_operations; 485 inode->i_fop = &simple_dir_operations; 486 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 487 inc_nlink(inode); 488 lockdep_annotate_inode_mutex_key(inode); 489 } 490 return inode; 491 } 492 493 static struct inode *hugetlbfs_get_inode(struct super_block *sb, 494 struct inode *dir, 495 umode_t mode, dev_t dev) 496 { 497 struct inode *inode; 498 499 inode = new_inode(sb); 500 if (inode) { 501 struct hugetlbfs_inode_info *info; 502 inode->i_ino = get_next_ino(); 503 inode_init_owner(inode, dir, mode); 504 inode->i_mapping->a_ops = &hugetlbfs_aops; 505 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info; 506 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 507 INIT_LIST_HEAD(&inode->i_mapping->private_list); 508 info = HUGETLBFS_I(inode); 509 /* 510 * The policy is initialized here even if we are creating a 511 * private inode because initialization simply creates an 512 * an empty rb tree and calls spin_lock_init(), later when we 513 * call mpol_free_shared_policy() it will just return because 514 * the rb tree will still be empty. 515 */ 516 mpol_shared_policy_init(&info->policy, NULL); 517 switch (mode & S_IFMT) { 518 default: 519 init_special_inode(inode, mode, dev); 520 break; 521 case S_IFREG: 522 inode->i_op = &hugetlbfs_inode_operations; 523 inode->i_fop = &hugetlbfs_file_operations; 524 break; 525 case S_IFDIR: 526 inode->i_op = &hugetlbfs_dir_inode_operations; 527 inode->i_fop = &simple_dir_operations; 528 529 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 530 inc_nlink(inode); 531 break; 532 case S_IFLNK: 533 inode->i_op = &page_symlink_inode_operations; 534 break; 535 } 536 lockdep_annotate_inode_mutex_key(inode); 537 } 538 return inode; 539 } 540 541 /* 542 * File creation. Allocate an inode, and we're done.. 543 */ 544 static int hugetlbfs_mknod(struct inode *dir, 545 struct dentry *dentry, umode_t mode, dev_t dev) 546 { 547 struct inode *inode; 548 int error = -ENOSPC; 549 550 inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev); 551 if (inode) { 552 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 553 d_instantiate(dentry, inode); 554 dget(dentry); /* Extra count - pin the dentry in core */ 555 error = 0; 556 } 557 return error; 558 } 559 560 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 561 { 562 int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0); 563 if (!retval) 564 inc_nlink(dir); 565 return retval; 566 } 567 568 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) 569 { 570 return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0); 571 } 572 573 static int hugetlbfs_symlink(struct inode *dir, 574 struct dentry *dentry, const char *symname) 575 { 576 struct inode *inode; 577 int error = -ENOSPC; 578 579 inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0); 580 if (inode) { 581 int l = strlen(symname)+1; 582 error = page_symlink(inode, symname, l); 583 if (!error) { 584 d_instantiate(dentry, inode); 585 dget(dentry); 586 } else 587 iput(inode); 588 } 589 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 590 591 return error; 592 } 593 594 /* 595 * mark the head page dirty 596 */ 597 static int hugetlbfs_set_page_dirty(struct page *page) 598 { 599 struct page *head = compound_head(page); 600 601 SetPageDirty(head); 602 return 0; 603 } 604 605 static int hugetlbfs_migrate_page(struct address_space *mapping, 606 struct page *newpage, struct page *page, 607 enum migrate_mode mode) 608 { 609 int rc; 610 611 rc = migrate_huge_page_move_mapping(mapping, newpage, page); 612 if (rc) 613 return rc; 614 migrate_page_copy(newpage, page); 615 616 return 0; 617 } 618 619 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf) 620 { 621 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb); 622 struct hstate *h = hstate_inode(dentry->d_inode); 623 624 buf->f_type = HUGETLBFS_MAGIC; 625 buf->f_bsize = huge_page_size(h); 626 if (sbinfo) { 627 spin_lock(&sbinfo->stat_lock); 628 /* If no limits set, just report 0 for max/free/used 629 * blocks, like simple_statfs() */ 630 if (sbinfo->spool) { 631 long free_pages; 632 633 spin_lock(&sbinfo->spool->lock); 634 buf->f_blocks = sbinfo->spool->max_hpages; 635 free_pages = sbinfo->spool->max_hpages 636 - sbinfo->spool->used_hpages; 637 buf->f_bavail = buf->f_bfree = free_pages; 638 spin_unlock(&sbinfo->spool->lock); 639 buf->f_files = sbinfo->max_inodes; 640 buf->f_ffree = sbinfo->free_inodes; 641 } 642 spin_unlock(&sbinfo->stat_lock); 643 } 644 buf->f_namelen = NAME_MAX; 645 return 0; 646 } 647 648 static void hugetlbfs_put_super(struct super_block *sb) 649 { 650 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb); 651 652 if (sbi) { 653 sb->s_fs_info = NULL; 654 655 if (sbi->spool) 656 hugepage_put_subpool(sbi->spool); 657 658 kfree(sbi); 659 } 660 } 661 662 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo) 663 { 664 if (sbinfo->free_inodes >= 0) { 665 spin_lock(&sbinfo->stat_lock); 666 if (unlikely(!sbinfo->free_inodes)) { 667 spin_unlock(&sbinfo->stat_lock); 668 return 0; 669 } 670 sbinfo->free_inodes--; 671 spin_unlock(&sbinfo->stat_lock); 672 } 673 674 return 1; 675 } 676 677 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo) 678 { 679 if (sbinfo->free_inodes >= 0) { 680 spin_lock(&sbinfo->stat_lock); 681 sbinfo->free_inodes++; 682 spin_unlock(&sbinfo->stat_lock); 683 } 684 } 685 686 687 static struct kmem_cache *hugetlbfs_inode_cachep; 688 689 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb) 690 { 691 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb); 692 struct hugetlbfs_inode_info *p; 693 694 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo))) 695 return NULL; 696 p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL); 697 if (unlikely(!p)) { 698 hugetlbfs_inc_free_inodes(sbinfo); 699 return NULL; 700 } 701 return &p->vfs_inode; 702 } 703 704 static void hugetlbfs_i_callback(struct rcu_head *head) 705 { 706 struct inode *inode = container_of(head, struct inode, i_rcu); 707 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode)); 708 } 709 710 static void hugetlbfs_destroy_inode(struct inode *inode) 711 { 712 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb)); 713 mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy); 714 call_rcu(&inode->i_rcu, hugetlbfs_i_callback); 715 } 716 717 static const struct address_space_operations hugetlbfs_aops = { 718 .write_begin = hugetlbfs_write_begin, 719 .write_end = hugetlbfs_write_end, 720 .set_page_dirty = hugetlbfs_set_page_dirty, 721 .migratepage = hugetlbfs_migrate_page, 722 }; 723 724 725 static void init_once(void *foo) 726 { 727 struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo; 728 729 inode_init_once(&ei->vfs_inode); 730 } 731 732 const struct file_operations hugetlbfs_file_operations = { 733 .read = hugetlbfs_read, 734 .mmap = hugetlbfs_file_mmap, 735 .fsync = noop_fsync, 736 .get_unmapped_area = hugetlb_get_unmapped_area, 737 .llseek = default_llseek, 738 }; 739 740 static const struct inode_operations hugetlbfs_dir_inode_operations = { 741 .create = hugetlbfs_create, 742 .lookup = simple_lookup, 743 .link = simple_link, 744 .unlink = simple_unlink, 745 .symlink = hugetlbfs_symlink, 746 .mkdir = hugetlbfs_mkdir, 747 .rmdir = simple_rmdir, 748 .mknod = hugetlbfs_mknod, 749 .rename = simple_rename, 750 .setattr = hugetlbfs_setattr, 751 }; 752 753 static const struct inode_operations hugetlbfs_inode_operations = { 754 .setattr = hugetlbfs_setattr, 755 }; 756 757 static const struct super_operations hugetlbfs_ops = { 758 .alloc_inode = hugetlbfs_alloc_inode, 759 .destroy_inode = hugetlbfs_destroy_inode, 760 .evict_inode = hugetlbfs_evict_inode, 761 .statfs = hugetlbfs_statfs, 762 .put_super = hugetlbfs_put_super, 763 .show_options = generic_show_options, 764 }; 765 766 static int 767 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig) 768 { 769 char *p, *rest; 770 substring_t args[MAX_OPT_ARGS]; 771 int option; 772 unsigned long long size = 0; 773 enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE; 774 775 if (!options) 776 return 0; 777 778 while ((p = strsep(&options, ",")) != NULL) { 779 int token; 780 if (!*p) 781 continue; 782 783 token = match_token(p, tokens, args); 784 switch (token) { 785 case Opt_uid: 786 if (match_int(&args[0], &option)) 787 goto bad_val; 788 pconfig->uid = option; 789 break; 790 791 case Opt_gid: 792 if (match_int(&args[0], &option)) 793 goto bad_val; 794 pconfig->gid = option; 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 }; 922 923 static struct vfsmount *hugetlbfs_vfsmount; 924 925 static int can_do_hugetlb_shm(void) 926 { 927 return capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group); 928 } 929 930 struct file *hugetlb_file_setup(const char *name, unsigned long addr, 931 size_t size, vm_flags_t acctflag, 932 struct user_struct **user, int creat_flags) 933 { 934 int error = -ENOMEM; 935 struct file *file; 936 struct inode *inode; 937 struct path path; 938 struct dentry *root; 939 struct qstr quick_string; 940 struct hstate *hstate; 941 unsigned long num_pages; 942 943 *user = NULL; 944 if (!hugetlbfs_vfsmount) 945 return ERR_PTR(-ENOENT); 946 947 if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) { 948 *user = current_user(); 949 if (user_shm_lock(size, *user)) { 950 task_lock(current); 951 printk_once(KERN_WARNING 952 "%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n", 953 current->comm, current->pid); 954 task_unlock(current); 955 } else { 956 *user = NULL; 957 return ERR_PTR(-EPERM); 958 } 959 } 960 961 root = hugetlbfs_vfsmount->mnt_root; 962 quick_string.name = name; 963 quick_string.len = strlen(quick_string.name); 964 quick_string.hash = 0; 965 path.dentry = d_alloc(root, &quick_string); 966 if (!path.dentry) 967 goto out_shm_unlock; 968 969 path.mnt = mntget(hugetlbfs_vfsmount); 970 error = -ENOSPC; 971 inode = hugetlbfs_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0); 972 if (!inode) 973 goto out_dentry; 974 975 hstate = hstate_inode(inode); 976 size += addr & ~huge_page_mask(hstate); 977 num_pages = ALIGN(size, huge_page_size(hstate)) >> 978 huge_page_shift(hstate); 979 error = -ENOMEM; 980 if (hugetlb_reserve_pages(inode, 0, num_pages, NULL, acctflag)) 981 goto out_inode; 982 983 d_instantiate(path.dentry, inode); 984 inode->i_size = size; 985 clear_nlink(inode); 986 987 error = -ENFILE; 988 file = alloc_file(&path, FMODE_WRITE | FMODE_READ, 989 &hugetlbfs_file_operations); 990 if (!file) 991 goto out_dentry; /* inode is already attached */ 992 993 return file; 994 995 out_inode: 996 iput(inode); 997 out_dentry: 998 path_put(&path); 999 out_shm_unlock: 1000 if (*user) { 1001 user_shm_unlock(size, *user); 1002 *user = NULL; 1003 } 1004 return ERR_PTR(error); 1005 } 1006 1007 static int __init init_hugetlbfs_fs(void) 1008 { 1009 int error; 1010 struct vfsmount *vfsmount; 1011 1012 error = bdi_init(&hugetlbfs_backing_dev_info); 1013 if (error) 1014 return error; 1015 1016 error = -ENOMEM; 1017 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache", 1018 sizeof(struct hugetlbfs_inode_info), 1019 0, 0, init_once); 1020 if (hugetlbfs_inode_cachep == NULL) 1021 goto out2; 1022 1023 error = register_filesystem(&hugetlbfs_fs_type); 1024 if (error) 1025 goto out; 1026 1027 vfsmount = kern_mount(&hugetlbfs_fs_type); 1028 1029 if (!IS_ERR(vfsmount)) { 1030 hugetlbfs_vfsmount = vfsmount; 1031 return 0; 1032 } 1033 1034 error = PTR_ERR(vfsmount); 1035 1036 out: 1037 kmem_cache_destroy(hugetlbfs_inode_cachep); 1038 out2: 1039 bdi_destroy(&hugetlbfs_backing_dev_info); 1040 return error; 1041 } 1042 1043 static void __exit exit_hugetlbfs_fs(void) 1044 { 1045 kmem_cache_destroy(hugetlbfs_inode_cachep); 1046 kern_unmount(hugetlbfs_vfsmount); 1047 unregister_filesystem(&hugetlbfs_fs_type); 1048 bdi_destroy(&hugetlbfs_backing_dev_info); 1049 } 1050 1051 module_init(init_hugetlbfs_fs) 1052 module_exit(exit_hugetlbfs_fs) 1053 1054 MODULE_LICENSE("GPL"); 1055