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 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->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_DONTEXPAND | VM_DONTDUMP; 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 rb_root *root, pgoff_t pgoff) 401 { 402 struct vm_area_struct *vma; 403 404 vma_interval_tree_foreach(vma, root, pgoff, ULONG_MAX) { 405 unsigned long v_offset; 406 407 /* 408 * Can the expression below overflow on 32-bit arches? 409 * No, because the interval tree returns us only those vmas 410 * which overlap the truncated area starting at pgoff, 411 * and no vma on a 32-bit arch can span beyond the 4GB. 412 */ 413 if (vma->vm_pgoff < pgoff) 414 v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT; 415 else 416 v_offset = 0; 417 418 unmap_hugepage_range(vma, vma->vm_start + v_offset, 419 vma->vm_end, NULL); 420 } 421 } 422 423 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset) 424 { 425 pgoff_t pgoff; 426 struct address_space *mapping = inode->i_mapping; 427 struct hstate *h = hstate_inode(inode); 428 429 BUG_ON(offset & ~huge_page_mask(h)); 430 pgoff = offset >> PAGE_SHIFT; 431 432 i_size_write(inode, offset); 433 mutex_lock(&mapping->i_mmap_mutex); 434 if (!RB_EMPTY_ROOT(&mapping->i_mmap)) 435 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff); 436 mutex_unlock(&mapping->i_mmap_mutex); 437 truncate_hugepages(inode, offset); 438 return 0; 439 } 440 441 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr) 442 { 443 struct inode *inode = dentry->d_inode; 444 struct hstate *h = hstate_inode(inode); 445 int error; 446 unsigned int ia_valid = attr->ia_valid; 447 448 BUG_ON(!inode); 449 450 error = inode_change_ok(inode, attr); 451 if (error) 452 return error; 453 454 if (ia_valid & ATTR_SIZE) { 455 error = -EINVAL; 456 if (attr->ia_size & ~huge_page_mask(h)) 457 return -EINVAL; 458 error = hugetlb_vmtruncate(inode, attr->ia_size); 459 if (error) 460 return error; 461 } 462 463 setattr_copy(inode, attr); 464 mark_inode_dirty(inode); 465 return 0; 466 } 467 468 static struct inode *hugetlbfs_get_root(struct super_block *sb, 469 struct hugetlbfs_config *config) 470 { 471 struct inode *inode; 472 473 inode = new_inode(sb); 474 if (inode) { 475 struct hugetlbfs_inode_info *info; 476 inode->i_ino = get_next_ino(); 477 inode->i_mode = S_IFDIR | config->mode; 478 inode->i_uid = config->uid; 479 inode->i_gid = config->gid; 480 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 481 info = HUGETLBFS_I(inode); 482 mpol_shared_policy_init(&info->policy, NULL); 483 inode->i_op = &hugetlbfs_dir_inode_operations; 484 inode->i_fop = &simple_dir_operations; 485 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 486 inc_nlink(inode); 487 lockdep_annotate_inode_mutex_key(inode); 488 } 489 return inode; 490 } 491 492 static struct inode *hugetlbfs_get_inode(struct super_block *sb, 493 struct inode *dir, 494 umode_t mode, dev_t dev) 495 { 496 struct inode *inode; 497 498 inode = new_inode(sb); 499 if (inode) { 500 struct hugetlbfs_inode_info *info; 501 inode->i_ino = get_next_ino(); 502 inode_init_owner(inode, dir, mode); 503 inode->i_mapping->a_ops = &hugetlbfs_aops; 504 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info; 505 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 506 INIT_LIST_HEAD(&inode->i_mapping->private_list); 507 info = HUGETLBFS_I(inode); 508 /* 509 * The policy is initialized here even if we are creating a 510 * private inode because initialization simply creates an 511 * an empty rb tree and calls spin_lock_init(), later when we 512 * call mpol_free_shared_policy() it will just return because 513 * the rb tree will still be empty. 514 */ 515 mpol_shared_policy_init(&info->policy, NULL); 516 switch (mode & S_IFMT) { 517 default: 518 init_special_inode(inode, mode, dev); 519 break; 520 case S_IFREG: 521 inode->i_op = &hugetlbfs_inode_operations; 522 inode->i_fop = &hugetlbfs_file_operations; 523 break; 524 case S_IFDIR: 525 inode->i_op = &hugetlbfs_dir_inode_operations; 526 inode->i_fop = &simple_dir_operations; 527 528 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 529 inc_nlink(inode); 530 break; 531 case S_IFLNK: 532 inode->i_op = &page_symlink_inode_operations; 533 break; 534 } 535 lockdep_annotate_inode_mutex_key(inode); 536 } 537 return inode; 538 } 539 540 /* 541 * File creation. Allocate an inode, and we're done.. 542 */ 543 static int hugetlbfs_mknod(struct inode *dir, 544 struct dentry *dentry, umode_t mode, dev_t dev) 545 { 546 struct inode *inode; 547 int error = -ENOSPC; 548 549 inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev); 550 if (inode) { 551 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 552 d_instantiate(dentry, inode); 553 dget(dentry); /* Extra count - pin the dentry in core */ 554 error = 0; 555 } 556 return error; 557 } 558 559 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 560 { 561 int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0); 562 if (!retval) 563 inc_nlink(dir); 564 return retval; 565 } 566 567 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) 568 { 569 return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0); 570 } 571 572 static int hugetlbfs_symlink(struct inode *dir, 573 struct dentry *dentry, const char *symname) 574 { 575 struct inode *inode; 576 int error = -ENOSPC; 577 578 inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0); 579 if (inode) { 580 int l = strlen(symname)+1; 581 error = page_symlink(inode, symname, l); 582 if (!error) { 583 d_instantiate(dentry, inode); 584 dget(dentry); 585 } else 586 iput(inode); 587 } 588 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 589 590 return error; 591 } 592 593 /* 594 * mark the head page dirty 595 */ 596 static int hugetlbfs_set_page_dirty(struct page *page) 597 { 598 struct page *head = compound_head(page); 599 600 SetPageDirty(head); 601 return 0; 602 } 603 604 static int hugetlbfs_migrate_page(struct address_space *mapping, 605 struct page *newpage, struct page *page, 606 enum migrate_mode mode) 607 { 608 int rc; 609 610 rc = migrate_huge_page_move_mapping(mapping, newpage, page); 611 if (rc) 612 return rc; 613 migrate_page_copy(newpage, page); 614 615 return 0; 616 } 617 618 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf) 619 { 620 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb); 621 struct hstate *h = hstate_inode(dentry->d_inode); 622 623 buf->f_type = HUGETLBFS_MAGIC; 624 buf->f_bsize = huge_page_size(h); 625 if (sbinfo) { 626 spin_lock(&sbinfo->stat_lock); 627 /* If no limits set, just report 0 for max/free/used 628 * blocks, like simple_statfs() */ 629 if (sbinfo->spool) { 630 long free_pages; 631 632 spin_lock(&sbinfo->spool->lock); 633 buf->f_blocks = sbinfo->spool->max_hpages; 634 free_pages = sbinfo->spool->max_hpages 635 - sbinfo->spool->used_hpages; 636 buf->f_bavail = buf->f_bfree = free_pages; 637 spin_unlock(&sbinfo->spool->lock); 638 buf->f_files = sbinfo->max_inodes; 639 buf->f_ffree = sbinfo->free_inodes; 640 } 641 spin_unlock(&sbinfo->stat_lock); 642 } 643 buf->f_namelen = NAME_MAX; 644 return 0; 645 } 646 647 static void hugetlbfs_put_super(struct super_block *sb) 648 { 649 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb); 650 651 if (sbi) { 652 sb->s_fs_info = NULL; 653 654 if (sbi->spool) 655 hugepage_put_subpool(sbi->spool); 656 657 kfree(sbi); 658 } 659 } 660 661 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo) 662 { 663 if (sbinfo->free_inodes >= 0) { 664 spin_lock(&sbinfo->stat_lock); 665 if (unlikely(!sbinfo->free_inodes)) { 666 spin_unlock(&sbinfo->stat_lock); 667 return 0; 668 } 669 sbinfo->free_inodes--; 670 spin_unlock(&sbinfo->stat_lock); 671 } 672 673 return 1; 674 } 675 676 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo) 677 { 678 if (sbinfo->free_inodes >= 0) { 679 spin_lock(&sbinfo->stat_lock); 680 sbinfo->free_inodes++; 681 spin_unlock(&sbinfo->stat_lock); 682 } 683 } 684 685 686 static struct kmem_cache *hugetlbfs_inode_cachep; 687 688 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb) 689 { 690 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb); 691 struct hugetlbfs_inode_info *p; 692 693 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo))) 694 return NULL; 695 p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL); 696 if (unlikely(!p)) { 697 hugetlbfs_inc_free_inodes(sbinfo); 698 return NULL; 699 } 700 return &p->vfs_inode; 701 } 702 703 static void hugetlbfs_i_callback(struct rcu_head *head) 704 { 705 struct inode *inode = container_of(head, struct inode, i_rcu); 706 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode)); 707 } 708 709 static void hugetlbfs_destroy_inode(struct inode *inode) 710 { 711 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb)); 712 mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy); 713 call_rcu(&inode->i_rcu, hugetlbfs_i_callback); 714 } 715 716 static const struct address_space_operations hugetlbfs_aops = { 717 .write_begin = hugetlbfs_write_begin, 718 .write_end = hugetlbfs_write_end, 719 .set_page_dirty = hugetlbfs_set_page_dirty, 720 .migratepage = hugetlbfs_migrate_page, 721 }; 722 723 724 static void init_once(void *foo) 725 { 726 struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo; 727 728 inode_init_once(&ei->vfs_inode); 729 } 730 731 const struct file_operations hugetlbfs_file_operations = { 732 .read = hugetlbfs_read, 733 .mmap = hugetlbfs_file_mmap, 734 .fsync = noop_fsync, 735 .get_unmapped_area = hugetlb_get_unmapped_area, 736 .llseek = default_llseek, 737 }; 738 739 static const struct inode_operations hugetlbfs_dir_inode_operations = { 740 .create = hugetlbfs_create, 741 .lookup = simple_lookup, 742 .link = simple_link, 743 .unlink = simple_unlink, 744 .symlink = hugetlbfs_symlink, 745 .mkdir = hugetlbfs_mkdir, 746 .rmdir = simple_rmdir, 747 .mknod = hugetlbfs_mknod, 748 .rename = simple_rename, 749 .setattr = hugetlbfs_setattr, 750 }; 751 752 static const struct inode_operations hugetlbfs_inode_operations = { 753 .setattr = hugetlbfs_setattr, 754 }; 755 756 static const struct super_operations hugetlbfs_ops = { 757 .alloc_inode = hugetlbfs_alloc_inode, 758 .destroy_inode = hugetlbfs_destroy_inode, 759 .evict_inode = hugetlbfs_evict_inode, 760 .statfs = hugetlbfs_statfs, 761 .put_super = hugetlbfs_put_super, 762 .show_options = generic_show_options, 763 }; 764 765 static int 766 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig) 767 { 768 char *p, *rest; 769 substring_t args[MAX_OPT_ARGS]; 770 int option; 771 unsigned long long size = 0; 772 enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE; 773 774 if (!options) 775 return 0; 776 777 while ((p = strsep(&options, ",")) != NULL) { 778 int token; 779 if (!*p) 780 continue; 781 782 token = match_token(p, tokens, args); 783 switch (token) { 784 case Opt_uid: 785 if (match_int(&args[0], &option)) 786 goto bad_val; 787 pconfig->uid = make_kuid(current_user_ns(), option); 788 if (!uid_valid(pconfig->uid)) 789 goto bad_val; 790 break; 791 792 case Opt_gid: 793 if (match_int(&args[0], &option)) 794 goto bad_val; 795 pconfig->gid = make_kgid(current_user_ns(), option); 796 if (!gid_valid(pconfig->gid)) 797 goto bad_val; 798 break; 799 800 case Opt_mode: 801 if (match_octal(&args[0], &option)) 802 goto bad_val; 803 pconfig->mode = option & 01777U; 804 break; 805 806 case Opt_size: { 807 /* memparse() will accept a K/M/G without a digit */ 808 if (!isdigit(*args[0].from)) 809 goto bad_val; 810 size = memparse(args[0].from, &rest); 811 setsize = SIZE_STD; 812 if (*rest == '%') 813 setsize = SIZE_PERCENT; 814 break; 815 } 816 817 case Opt_nr_inodes: 818 /* memparse() will accept a K/M/G without a digit */ 819 if (!isdigit(*args[0].from)) 820 goto bad_val; 821 pconfig->nr_inodes = memparse(args[0].from, &rest); 822 break; 823 824 case Opt_pagesize: { 825 unsigned long ps; 826 ps = memparse(args[0].from, &rest); 827 pconfig->hstate = size_to_hstate(ps); 828 if (!pconfig->hstate) { 829 printk(KERN_ERR 830 "hugetlbfs: Unsupported page size %lu MB\n", 831 ps >> 20); 832 return -EINVAL; 833 } 834 break; 835 } 836 837 default: 838 printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n", 839 p); 840 return -EINVAL; 841 break; 842 } 843 } 844 845 /* Do size after hstate is set up */ 846 if (setsize > NO_SIZE) { 847 struct hstate *h = pconfig->hstate; 848 if (setsize == SIZE_PERCENT) { 849 size <<= huge_page_shift(h); 850 size *= h->max_huge_pages; 851 do_div(size, 100); 852 } 853 pconfig->nr_blocks = (size >> huge_page_shift(h)); 854 } 855 856 return 0; 857 858 bad_val: 859 printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n", 860 args[0].from, p); 861 return -EINVAL; 862 } 863 864 static int 865 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent) 866 { 867 int ret; 868 struct hugetlbfs_config config; 869 struct hugetlbfs_sb_info *sbinfo; 870 871 save_mount_options(sb, data); 872 873 config.nr_blocks = -1; /* No limit on size by default */ 874 config.nr_inodes = -1; /* No limit on number of inodes by default */ 875 config.uid = current_fsuid(); 876 config.gid = current_fsgid(); 877 config.mode = 0755; 878 config.hstate = &default_hstate; 879 ret = hugetlbfs_parse_options(data, &config); 880 if (ret) 881 return ret; 882 883 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL); 884 if (!sbinfo) 885 return -ENOMEM; 886 sb->s_fs_info = sbinfo; 887 sbinfo->hstate = config.hstate; 888 spin_lock_init(&sbinfo->stat_lock); 889 sbinfo->max_inodes = config.nr_inodes; 890 sbinfo->free_inodes = config.nr_inodes; 891 sbinfo->spool = NULL; 892 if (config.nr_blocks != -1) { 893 sbinfo->spool = hugepage_new_subpool(config.nr_blocks); 894 if (!sbinfo->spool) 895 goto out_free; 896 } 897 sb->s_maxbytes = MAX_LFS_FILESIZE; 898 sb->s_blocksize = huge_page_size(config.hstate); 899 sb->s_blocksize_bits = huge_page_shift(config.hstate); 900 sb->s_magic = HUGETLBFS_MAGIC; 901 sb->s_op = &hugetlbfs_ops; 902 sb->s_time_gran = 1; 903 sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config)); 904 if (!sb->s_root) 905 goto out_free; 906 return 0; 907 out_free: 908 if (sbinfo->spool) 909 kfree(sbinfo->spool); 910 kfree(sbinfo); 911 return -ENOMEM; 912 } 913 914 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type, 915 int flags, const char *dev_name, void *data) 916 { 917 return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super); 918 } 919 920 static struct file_system_type hugetlbfs_fs_type = { 921 .name = "hugetlbfs", 922 .mount = hugetlbfs_mount, 923 .kill_sb = kill_litter_super, 924 }; 925 926 static struct vfsmount *hugetlbfs_vfsmount; 927 928 static int can_do_hugetlb_shm(void) 929 { 930 kgid_t shm_group; 931 shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group); 932 return capable(CAP_IPC_LOCK) || in_group_p(shm_group); 933 } 934 935 struct file *hugetlb_file_setup(const char *name, unsigned long addr, 936 size_t size, vm_flags_t acctflag, 937 struct user_struct **user, int creat_flags) 938 { 939 int error = -ENOMEM; 940 struct file *file; 941 struct inode *inode; 942 struct path path; 943 struct dentry *root; 944 struct qstr quick_string; 945 struct hstate *hstate; 946 unsigned long num_pages; 947 948 *user = NULL; 949 if (!hugetlbfs_vfsmount) 950 return ERR_PTR(-ENOENT); 951 952 if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) { 953 *user = current_user(); 954 if (user_shm_lock(size, *user)) { 955 task_lock(current); 956 printk_once(KERN_WARNING 957 "%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n", 958 current->comm, current->pid); 959 task_unlock(current); 960 } else { 961 *user = NULL; 962 return ERR_PTR(-EPERM); 963 } 964 } 965 966 root = hugetlbfs_vfsmount->mnt_root; 967 quick_string.name = name; 968 quick_string.len = strlen(quick_string.name); 969 quick_string.hash = 0; 970 path.dentry = d_alloc(root, &quick_string); 971 if (!path.dentry) 972 goto out_shm_unlock; 973 974 path.mnt = mntget(hugetlbfs_vfsmount); 975 error = -ENOSPC; 976 inode = hugetlbfs_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0); 977 if (!inode) 978 goto out_dentry; 979 980 hstate = hstate_inode(inode); 981 size += addr & ~huge_page_mask(hstate); 982 num_pages = ALIGN(size, huge_page_size(hstate)) >> 983 huge_page_shift(hstate); 984 error = -ENOMEM; 985 if (hugetlb_reserve_pages(inode, 0, num_pages, NULL, acctflag)) 986 goto out_inode; 987 988 d_instantiate(path.dentry, inode); 989 inode->i_size = size; 990 clear_nlink(inode); 991 992 error = -ENFILE; 993 file = alloc_file(&path, FMODE_WRITE | FMODE_READ, 994 &hugetlbfs_file_operations); 995 if (!file) 996 goto out_dentry; /* inode is already attached */ 997 998 return file; 999 1000 out_inode: 1001 iput(inode); 1002 out_dentry: 1003 path_put(&path); 1004 out_shm_unlock: 1005 if (*user) { 1006 user_shm_unlock(size, *user); 1007 *user = NULL; 1008 } 1009 return ERR_PTR(error); 1010 } 1011 1012 static int __init init_hugetlbfs_fs(void) 1013 { 1014 int error; 1015 struct vfsmount *vfsmount; 1016 1017 error = bdi_init(&hugetlbfs_backing_dev_info); 1018 if (error) 1019 return error; 1020 1021 error = -ENOMEM; 1022 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache", 1023 sizeof(struct hugetlbfs_inode_info), 1024 0, 0, init_once); 1025 if (hugetlbfs_inode_cachep == NULL) 1026 goto out2; 1027 1028 error = register_filesystem(&hugetlbfs_fs_type); 1029 if (error) 1030 goto out; 1031 1032 vfsmount = kern_mount(&hugetlbfs_fs_type); 1033 1034 if (!IS_ERR(vfsmount)) { 1035 hugetlbfs_vfsmount = vfsmount; 1036 return 0; 1037 } 1038 1039 error = PTR_ERR(vfsmount); 1040 1041 out: 1042 kmem_cache_destroy(hugetlbfs_inode_cachep); 1043 out2: 1044 bdi_destroy(&hugetlbfs_backing_dev_info); 1045 return error; 1046 } 1047 1048 static void __exit exit_hugetlbfs_fs(void) 1049 { 1050 /* 1051 * Make sure all delayed rcu free inodes are flushed before we 1052 * destroy cache. 1053 */ 1054 rcu_barrier(); 1055 kmem_cache_destroy(hugetlbfs_inode_cachep); 1056 kern_unmount(hugetlbfs_vfsmount); 1057 unregister_filesystem(&hugetlbfs_fs_type); 1058 bdi_destroy(&hugetlbfs_backing_dev_info); 1059 } 1060 1061 module_init(init_hugetlbfs_fs) 1062 module_exit(exit_hugetlbfs_fs) 1063 1064 MODULE_LICENSE("GPL"); 1065