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 static struct backing_dev_info hugetlbfs_backing_dev_info = { 45 .name = "hugetlbfs", 46 .ra_pages = 0, /* No readahead */ 47 .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, 48 }; 49 50 int sysctl_hugetlb_shm_group; 51 52 enum { 53 Opt_size, Opt_nr_inodes, 54 Opt_mode, Opt_uid, Opt_gid, 55 Opt_pagesize, 56 Opt_err, 57 }; 58 59 static const match_table_t tokens = { 60 {Opt_size, "size=%s"}, 61 {Opt_nr_inodes, "nr_inodes=%s"}, 62 {Opt_mode, "mode=%o"}, 63 {Opt_uid, "uid=%u"}, 64 {Opt_gid, "gid=%u"}, 65 {Opt_pagesize, "pagesize=%s"}, 66 {Opt_err, NULL}, 67 }; 68 69 static void huge_pagevec_release(struct pagevec *pvec) 70 { 71 int i; 72 73 for (i = 0; i < pagevec_count(pvec); ++i) 74 put_page(pvec->pages[i]); 75 76 pagevec_reinit(pvec); 77 } 78 79 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma) 80 { 81 struct inode *inode = file->f_path.dentry->d_inode; 82 loff_t len, vma_len; 83 int ret; 84 struct hstate *h = hstate_file(file); 85 86 /* 87 * vma address alignment (but not the pgoff alignment) has 88 * already been checked by prepare_hugepage_range. If you add 89 * any error returns here, do so after setting VM_HUGETLB, so 90 * is_vm_hugetlb_page tests below unmap_region go the right 91 * way when do_mmap_pgoff unwinds (may be important on powerpc 92 * and ia64). 93 */ 94 vma->vm_flags |= VM_HUGETLB | VM_RESERVED; 95 vma->vm_ops = &hugetlb_vm_ops; 96 97 if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT)) 98 return -EINVAL; 99 100 vma_len = (loff_t)(vma->vm_end - vma->vm_start); 101 102 mutex_lock(&inode->i_mutex); 103 file_accessed(file); 104 105 ret = -ENOMEM; 106 len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); 107 108 if (hugetlb_reserve_pages(inode, 109 vma->vm_pgoff >> huge_page_order(h), 110 len >> huge_page_shift(h), vma, 111 vma->vm_flags)) 112 goto out; 113 114 ret = 0; 115 hugetlb_prefault_arch_hook(vma->vm_mm); 116 if (vma->vm_flags & VM_WRITE && inode->i_size < len) 117 inode->i_size = len; 118 out: 119 mutex_unlock(&inode->i_mutex); 120 121 return ret; 122 } 123 124 /* 125 * Called under down_write(mmap_sem). 126 */ 127 128 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA 129 static unsigned long 130 hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 131 unsigned long len, unsigned long pgoff, unsigned long flags) 132 { 133 struct mm_struct *mm = current->mm; 134 struct vm_area_struct *vma; 135 unsigned long start_addr; 136 struct hstate *h = hstate_file(file); 137 138 if (len & ~huge_page_mask(h)) 139 return -EINVAL; 140 if (len > TASK_SIZE) 141 return -ENOMEM; 142 143 if (flags & MAP_FIXED) { 144 if (prepare_hugepage_range(file, addr, len)) 145 return -EINVAL; 146 return addr; 147 } 148 149 if (addr) { 150 addr = ALIGN(addr, huge_page_size(h)); 151 vma = find_vma(mm, addr); 152 if (TASK_SIZE - len >= addr && 153 (!vma || addr + len <= vma->vm_start)) 154 return addr; 155 } 156 157 start_addr = mm->free_area_cache; 158 159 if (len <= mm->cached_hole_size) 160 start_addr = TASK_UNMAPPED_BASE; 161 162 full_search: 163 addr = ALIGN(start_addr, huge_page_size(h)); 164 165 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { 166 /* At this point: (!vma || addr < vma->vm_end). */ 167 if (TASK_SIZE - len < addr) { 168 /* 169 * Start a new search - just in case we missed 170 * some holes. 171 */ 172 if (start_addr != TASK_UNMAPPED_BASE) { 173 start_addr = TASK_UNMAPPED_BASE; 174 goto full_search; 175 } 176 return -ENOMEM; 177 } 178 179 if (!vma || addr + len <= vma->vm_start) 180 return addr; 181 addr = ALIGN(vma->vm_end, huge_page_size(h)); 182 } 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 mutex_lock(&inode->i_mutex); 242 243 /* validate length */ 244 if (len == 0) 245 goto out; 246 247 isize = i_size_read(inode); 248 if (!isize) 249 goto out; 250 251 end_index = (isize - 1) >> huge_page_shift(h); 252 for (;;) { 253 struct page *page; 254 unsigned long nr, ret; 255 int ra; 256 257 /* nr is the maximum number of bytes to copy from this page */ 258 nr = huge_page_size(h); 259 if (index >= end_index) { 260 if (index > end_index) 261 goto out; 262 nr = ((isize - 1) & ~huge_page_mask(h)) + 1; 263 if (nr <= offset) { 264 goto out; 265 } 266 } 267 nr = nr - offset; 268 269 /* Find the page */ 270 page = find_get_page(mapping, index); 271 if (unlikely(page == NULL)) { 272 /* 273 * We have a HOLE, zero out the user-buffer for the 274 * length of the hole or request. 275 */ 276 ret = len < nr ? len : nr; 277 if (clear_user(buf, ret)) 278 ra = -EFAULT; 279 else 280 ra = 0; 281 } else { 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 } 288 if (ra < 0) { 289 if (retval == 0) 290 retval = ra; 291 if (page) 292 page_cache_release(page); 293 goto out; 294 } 295 296 offset += ret; 297 retval += ret; 298 len -= ret; 299 index += offset >> huge_page_shift(h); 300 offset &= ~huge_page_mask(h); 301 302 if (page) 303 page_cache_release(page); 304 305 /* short read or no more work */ 306 if ((ret != nr) || (len == 0)) 307 break; 308 } 309 out: 310 *ppos = ((loff_t)index << huge_page_shift(h)) + offset; 311 mutex_unlock(&inode->i_mutex); 312 return retval; 313 } 314 315 static int hugetlbfs_write_begin(struct file *file, 316 struct address_space *mapping, 317 loff_t pos, unsigned len, unsigned flags, 318 struct page **pagep, void **fsdata) 319 { 320 return -EINVAL; 321 } 322 323 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping, 324 loff_t pos, unsigned len, unsigned copied, 325 struct page *page, void *fsdata) 326 { 327 BUG(); 328 return -EINVAL; 329 } 330 331 static void truncate_huge_page(struct page *page) 332 { 333 cancel_dirty_page(page, /* No IO accounting for huge pages? */0); 334 ClearPageUptodate(page); 335 delete_from_page_cache(page); 336 } 337 338 static void truncate_hugepages(struct inode *inode, loff_t lstart) 339 { 340 struct hstate *h = hstate_inode(inode); 341 struct address_space *mapping = &inode->i_data; 342 const pgoff_t start = lstart >> huge_page_shift(h); 343 struct pagevec pvec; 344 pgoff_t next; 345 int i, freed = 0; 346 347 pagevec_init(&pvec, 0); 348 next = start; 349 while (1) { 350 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { 351 if (next == start) 352 break; 353 next = start; 354 continue; 355 } 356 357 for (i = 0; i < pagevec_count(&pvec); ++i) { 358 struct page *page = pvec.pages[i]; 359 360 lock_page(page); 361 if (page->index > next) 362 next = page->index; 363 ++next; 364 truncate_huge_page(page); 365 unlock_page(page); 366 freed++; 367 } 368 huge_pagevec_release(&pvec); 369 } 370 BUG_ON(!lstart && mapping->nrpages); 371 hugetlb_unreserve_pages(inode, start, freed); 372 } 373 374 static void hugetlbfs_evict_inode(struct inode *inode) 375 { 376 truncate_hugepages(inode, 0); 377 end_writeback(inode); 378 } 379 380 static inline void 381 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff) 382 { 383 struct vm_area_struct *vma; 384 struct prio_tree_iter iter; 385 386 vma_prio_tree_foreach(vma, &iter, 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 prio_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, 401 vma->vm_start + v_offset, 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 (!prio_tree_empty(&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 } 470 return inode; 471 } 472 473 static struct inode *hugetlbfs_get_inode(struct super_block *sb, 474 struct inode *dir, 475 umode_t mode, dev_t dev) 476 { 477 struct inode *inode; 478 479 inode = new_inode(sb); 480 if (inode) { 481 struct hugetlbfs_inode_info *info; 482 inode->i_ino = get_next_ino(); 483 inode_init_owner(inode, dir, mode); 484 inode->i_mapping->a_ops = &hugetlbfs_aops; 485 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info; 486 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 487 INIT_LIST_HEAD(&inode->i_mapping->private_list); 488 info = HUGETLBFS_I(inode); 489 /* 490 * The policy is initialized here even if we are creating a 491 * private inode because initialization simply creates an 492 * an empty rb tree and calls spin_lock_init(), later when we 493 * call mpol_free_shared_policy() it will just return because 494 * the rb tree will still be empty. 495 */ 496 mpol_shared_policy_init(&info->policy, NULL); 497 switch (mode & S_IFMT) { 498 default: 499 init_special_inode(inode, mode, dev); 500 break; 501 case S_IFREG: 502 inode->i_op = &hugetlbfs_inode_operations; 503 inode->i_fop = &hugetlbfs_file_operations; 504 break; 505 case S_IFDIR: 506 inode->i_op = &hugetlbfs_dir_inode_operations; 507 inode->i_fop = &simple_dir_operations; 508 509 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 510 inc_nlink(inode); 511 break; 512 case S_IFLNK: 513 inode->i_op = &page_symlink_inode_operations; 514 break; 515 } 516 lockdep_annotate_inode_mutex_key(inode); 517 } 518 return inode; 519 } 520 521 /* 522 * File creation. Allocate an inode, and we're done.. 523 */ 524 static int hugetlbfs_mknod(struct inode *dir, 525 struct dentry *dentry, umode_t mode, dev_t dev) 526 { 527 struct inode *inode; 528 int error = -ENOSPC; 529 530 inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev); 531 if (inode) { 532 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 533 d_instantiate(dentry, inode); 534 dget(dentry); /* Extra count - pin the dentry in core */ 535 error = 0; 536 } 537 return error; 538 } 539 540 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 541 { 542 int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0); 543 if (!retval) 544 inc_nlink(dir); 545 return retval; 546 } 547 548 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, struct nameidata *nd) 549 { 550 return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0); 551 } 552 553 static int hugetlbfs_symlink(struct inode *dir, 554 struct dentry *dentry, const char *symname) 555 { 556 struct inode *inode; 557 int error = -ENOSPC; 558 559 inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0); 560 if (inode) { 561 int l = strlen(symname)+1; 562 error = page_symlink(inode, symname, l); 563 if (!error) { 564 d_instantiate(dentry, inode); 565 dget(dentry); 566 } else 567 iput(inode); 568 } 569 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 570 571 return error; 572 } 573 574 /* 575 * mark the head page dirty 576 */ 577 static int hugetlbfs_set_page_dirty(struct page *page) 578 { 579 struct page *head = compound_head(page); 580 581 SetPageDirty(head); 582 return 0; 583 } 584 585 static int hugetlbfs_migrate_page(struct address_space *mapping, 586 struct page *newpage, struct page *page, 587 enum migrate_mode mode) 588 { 589 int rc; 590 591 rc = migrate_huge_page_move_mapping(mapping, newpage, page); 592 if (rc) 593 return rc; 594 migrate_page_copy(newpage, page); 595 596 return 0; 597 } 598 599 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf) 600 { 601 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb); 602 struct hstate *h = hstate_inode(dentry->d_inode); 603 604 buf->f_type = HUGETLBFS_MAGIC; 605 buf->f_bsize = huge_page_size(h); 606 if (sbinfo) { 607 spin_lock(&sbinfo->stat_lock); 608 /* If no limits set, just report 0 for max/free/used 609 * blocks, like simple_statfs() */ 610 if (sbinfo->max_blocks >= 0) { 611 buf->f_blocks = sbinfo->max_blocks; 612 buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; 613 buf->f_files = sbinfo->max_inodes; 614 buf->f_ffree = sbinfo->free_inodes; 615 } 616 spin_unlock(&sbinfo->stat_lock); 617 } 618 buf->f_namelen = NAME_MAX; 619 return 0; 620 } 621 622 static void hugetlbfs_put_super(struct super_block *sb) 623 { 624 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb); 625 626 if (sbi) { 627 sb->s_fs_info = NULL; 628 kfree(sbi); 629 } 630 } 631 632 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo) 633 { 634 if (sbinfo->free_inodes >= 0) { 635 spin_lock(&sbinfo->stat_lock); 636 if (unlikely(!sbinfo->free_inodes)) { 637 spin_unlock(&sbinfo->stat_lock); 638 return 0; 639 } 640 sbinfo->free_inodes--; 641 spin_unlock(&sbinfo->stat_lock); 642 } 643 644 return 1; 645 } 646 647 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo) 648 { 649 if (sbinfo->free_inodes >= 0) { 650 spin_lock(&sbinfo->stat_lock); 651 sbinfo->free_inodes++; 652 spin_unlock(&sbinfo->stat_lock); 653 } 654 } 655 656 657 static struct kmem_cache *hugetlbfs_inode_cachep; 658 659 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb) 660 { 661 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb); 662 struct hugetlbfs_inode_info *p; 663 664 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo))) 665 return NULL; 666 p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL); 667 if (unlikely(!p)) { 668 hugetlbfs_inc_free_inodes(sbinfo); 669 return NULL; 670 } 671 return &p->vfs_inode; 672 } 673 674 static void hugetlbfs_i_callback(struct rcu_head *head) 675 { 676 struct inode *inode = container_of(head, struct inode, i_rcu); 677 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode)); 678 } 679 680 static void hugetlbfs_destroy_inode(struct inode *inode) 681 { 682 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb)); 683 mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy); 684 call_rcu(&inode->i_rcu, hugetlbfs_i_callback); 685 } 686 687 static const struct address_space_operations hugetlbfs_aops = { 688 .write_begin = hugetlbfs_write_begin, 689 .write_end = hugetlbfs_write_end, 690 .set_page_dirty = hugetlbfs_set_page_dirty, 691 .migratepage = hugetlbfs_migrate_page, 692 }; 693 694 695 static void init_once(void *foo) 696 { 697 struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo; 698 699 inode_init_once(&ei->vfs_inode); 700 } 701 702 const struct file_operations hugetlbfs_file_operations = { 703 .read = hugetlbfs_read, 704 .mmap = hugetlbfs_file_mmap, 705 .fsync = noop_fsync, 706 .get_unmapped_area = hugetlb_get_unmapped_area, 707 .llseek = default_llseek, 708 }; 709 710 static const struct inode_operations hugetlbfs_dir_inode_operations = { 711 .create = hugetlbfs_create, 712 .lookup = simple_lookup, 713 .link = simple_link, 714 .unlink = simple_unlink, 715 .symlink = hugetlbfs_symlink, 716 .mkdir = hugetlbfs_mkdir, 717 .rmdir = simple_rmdir, 718 .mknod = hugetlbfs_mknod, 719 .rename = simple_rename, 720 .setattr = hugetlbfs_setattr, 721 }; 722 723 static const struct inode_operations hugetlbfs_inode_operations = { 724 .setattr = hugetlbfs_setattr, 725 }; 726 727 static const struct super_operations hugetlbfs_ops = { 728 .alloc_inode = hugetlbfs_alloc_inode, 729 .destroy_inode = hugetlbfs_destroy_inode, 730 .evict_inode = hugetlbfs_evict_inode, 731 .statfs = hugetlbfs_statfs, 732 .put_super = hugetlbfs_put_super, 733 .show_options = generic_show_options, 734 }; 735 736 static int 737 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig) 738 { 739 char *p, *rest; 740 substring_t args[MAX_OPT_ARGS]; 741 int option; 742 unsigned long long size = 0; 743 enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE; 744 745 if (!options) 746 return 0; 747 748 while ((p = strsep(&options, ",")) != NULL) { 749 int token; 750 if (!*p) 751 continue; 752 753 token = match_token(p, tokens, args); 754 switch (token) { 755 case Opt_uid: 756 if (match_int(&args[0], &option)) 757 goto bad_val; 758 pconfig->uid = option; 759 break; 760 761 case Opt_gid: 762 if (match_int(&args[0], &option)) 763 goto bad_val; 764 pconfig->gid = option; 765 break; 766 767 case Opt_mode: 768 if (match_octal(&args[0], &option)) 769 goto bad_val; 770 pconfig->mode = option & 01777U; 771 break; 772 773 case Opt_size: { 774 /* memparse() will accept a K/M/G without a digit */ 775 if (!isdigit(*args[0].from)) 776 goto bad_val; 777 size = memparse(args[0].from, &rest); 778 setsize = SIZE_STD; 779 if (*rest == '%') 780 setsize = SIZE_PERCENT; 781 break; 782 } 783 784 case Opt_nr_inodes: 785 /* memparse() will accept a K/M/G without a digit */ 786 if (!isdigit(*args[0].from)) 787 goto bad_val; 788 pconfig->nr_inodes = memparse(args[0].from, &rest); 789 break; 790 791 case Opt_pagesize: { 792 unsigned long ps; 793 ps = memparse(args[0].from, &rest); 794 pconfig->hstate = size_to_hstate(ps); 795 if (!pconfig->hstate) { 796 printk(KERN_ERR 797 "hugetlbfs: Unsupported page size %lu MB\n", 798 ps >> 20); 799 return -EINVAL; 800 } 801 break; 802 } 803 804 default: 805 printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n", 806 p); 807 return -EINVAL; 808 break; 809 } 810 } 811 812 /* Do size after hstate is set up */ 813 if (setsize > NO_SIZE) { 814 struct hstate *h = pconfig->hstate; 815 if (setsize == SIZE_PERCENT) { 816 size <<= huge_page_shift(h); 817 size *= h->max_huge_pages; 818 do_div(size, 100); 819 } 820 pconfig->nr_blocks = (size >> huge_page_shift(h)); 821 } 822 823 return 0; 824 825 bad_val: 826 printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n", 827 args[0].from, p); 828 return -EINVAL; 829 } 830 831 static int 832 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent) 833 { 834 struct inode * inode; 835 struct dentry * root; 836 int ret; 837 struct hugetlbfs_config config; 838 struct hugetlbfs_sb_info *sbinfo; 839 840 save_mount_options(sb, data); 841 842 config.nr_blocks = -1; /* No limit on size by default */ 843 config.nr_inodes = -1; /* No limit on number of inodes by default */ 844 config.uid = current_fsuid(); 845 config.gid = current_fsgid(); 846 config.mode = 0755; 847 config.hstate = &default_hstate; 848 ret = hugetlbfs_parse_options(data, &config); 849 if (ret) 850 return ret; 851 852 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL); 853 if (!sbinfo) 854 return -ENOMEM; 855 sb->s_fs_info = sbinfo; 856 sbinfo->hstate = config.hstate; 857 spin_lock_init(&sbinfo->stat_lock); 858 sbinfo->max_blocks = config.nr_blocks; 859 sbinfo->free_blocks = config.nr_blocks; 860 sbinfo->max_inodes = config.nr_inodes; 861 sbinfo->free_inodes = config.nr_inodes; 862 sb->s_maxbytes = MAX_LFS_FILESIZE; 863 sb->s_blocksize = huge_page_size(config.hstate); 864 sb->s_blocksize_bits = huge_page_shift(config.hstate); 865 sb->s_magic = HUGETLBFS_MAGIC; 866 sb->s_op = &hugetlbfs_ops; 867 sb->s_time_gran = 1; 868 inode = hugetlbfs_get_root(sb, &config); 869 if (!inode) 870 goto out_free; 871 872 root = d_alloc_root(inode); 873 if (!root) { 874 iput(inode); 875 goto out_free; 876 } 877 sb->s_root = root; 878 return 0; 879 out_free: 880 kfree(sbinfo); 881 return -ENOMEM; 882 } 883 884 int hugetlb_get_quota(struct address_space *mapping, long delta) 885 { 886 int ret = 0; 887 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb); 888 889 if (sbinfo->free_blocks > -1) { 890 spin_lock(&sbinfo->stat_lock); 891 if (sbinfo->free_blocks - delta >= 0) 892 sbinfo->free_blocks -= delta; 893 else 894 ret = -ENOMEM; 895 spin_unlock(&sbinfo->stat_lock); 896 } 897 898 return ret; 899 } 900 901 void hugetlb_put_quota(struct address_space *mapping, long delta) 902 { 903 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb); 904 905 if (sbinfo->free_blocks > -1) { 906 spin_lock(&sbinfo->stat_lock); 907 sbinfo->free_blocks += delta; 908 spin_unlock(&sbinfo->stat_lock); 909 } 910 } 911 912 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type, 913 int flags, const char *dev_name, void *data) 914 { 915 return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super); 916 } 917 918 static struct file_system_type hugetlbfs_fs_type = { 919 .name = "hugetlbfs", 920 .mount = hugetlbfs_mount, 921 .kill_sb = kill_litter_super, 922 }; 923 924 static struct vfsmount *hugetlbfs_vfsmount; 925 926 static int can_do_hugetlb_shm(void) 927 { 928 return capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group); 929 } 930 931 struct file *hugetlb_file_setup(const char *name, size_t size, 932 vm_flags_t acctflag, 933 struct user_struct **user, int creat_flags) 934 { 935 int error = -ENOMEM; 936 struct file *file; 937 struct inode *inode; 938 struct path path; 939 struct dentry *root; 940 struct qstr quick_string; 941 942 *user = NULL; 943 if (!hugetlbfs_vfsmount) 944 return ERR_PTR(-ENOENT); 945 946 if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) { 947 *user = current_user(); 948 if (user_shm_lock(size, *user)) { 949 printk_once(KERN_WARNING "Using mlock ulimits for SHM_HUGETLB is deprecated\n"); 950 } else { 951 *user = NULL; 952 return ERR_PTR(-EPERM); 953 } 954 } 955 956 root = hugetlbfs_vfsmount->mnt_root; 957 quick_string.name = name; 958 quick_string.len = strlen(quick_string.name); 959 quick_string.hash = 0; 960 path.dentry = d_alloc(root, &quick_string); 961 if (!path.dentry) 962 goto out_shm_unlock; 963 964 path.mnt = mntget(hugetlbfs_vfsmount); 965 error = -ENOSPC; 966 inode = hugetlbfs_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0); 967 if (!inode) 968 goto out_dentry; 969 970 error = -ENOMEM; 971 if (hugetlb_reserve_pages(inode, 0, 972 size >> huge_page_shift(hstate_inode(inode)), NULL, 973 acctflag)) 974 goto out_inode; 975 976 d_instantiate(path.dentry, inode); 977 inode->i_size = size; 978 clear_nlink(inode); 979 980 error = -ENFILE; 981 file = alloc_file(&path, FMODE_WRITE | FMODE_READ, 982 &hugetlbfs_file_operations); 983 if (!file) 984 goto out_dentry; /* inode is already attached */ 985 986 return file; 987 988 out_inode: 989 iput(inode); 990 out_dentry: 991 path_put(&path); 992 out_shm_unlock: 993 if (*user) { 994 user_shm_unlock(size, *user); 995 *user = NULL; 996 } 997 return ERR_PTR(error); 998 } 999 1000 static int __init init_hugetlbfs_fs(void) 1001 { 1002 int error; 1003 struct vfsmount *vfsmount; 1004 1005 error = bdi_init(&hugetlbfs_backing_dev_info); 1006 if (error) 1007 return error; 1008 1009 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache", 1010 sizeof(struct hugetlbfs_inode_info), 1011 0, 0, init_once); 1012 if (hugetlbfs_inode_cachep == NULL) 1013 goto out2; 1014 1015 error = register_filesystem(&hugetlbfs_fs_type); 1016 if (error) 1017 goto out; 1018 1019 vfsmount = kern_mount(&hugetlbfs_fs_type); 1020 1021 if (!IS_ERR(vfsmount)) { 1022 hugetlbfs_vfsmount = vfsmount; 1023 return 0; 1024 } 1025 1026 error = PTR_ERR(vfsmount); 1027 1028 out: 1029 if (error) 1030 kmem_cache_destroy(hugetlbfs_inode_cachep); 1031 out2: 1032 bdi_destroy(&hugetlbfs_backing_dev_info); 1033 return error; 1034 } 1035 1036 static void __exit exit_hugetlbfs_fs(void) 1037 { 1038 kmem_cache_destroy(hugetlbfs_inode_cachep); 1039 kern_unmount(hugetlbfs_vfsmount); 1040 unregister_filesystem(&hugetlbfs_fs_type); 1041 bdi_destroy(&hugetlbfs_backing_dev_info); 1042 } 1043 1044 module_init(init_hugetlbfs_fs) 1045 module_exit(exit_hugetlbfs_fs) 1046 1047 MODULE_LICENSE("GPL"); 1048