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->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 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 truncate_hugepages(inode, 0); 370 clear_inode(inode); 371 } 372 373 static inline void 374 hugetlb_vmtruncate_list(struct rb_root *root, pgoff_t pgoff) 375 { 376 struct vm_area_struct *vma; 377 378 vma_interval_tree_foreach(vma, root, pgoff, ULONG_MAX) { 379 unsigned long v_offset; 380 381 /* 382 * Can the expression below overflow on 32-bit arches? 383 * No, because the interval tree returns us only those vmas 384 * which overlap the truncated area starting at pgoff, 385 * and no vma on a 32-bit arch can span beyond the 4GB. 386 */ 387 if (vma->vm_pgoff < pgoff) 388 v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT; 389 else 390 v_offset = 0; 391 392 unmap_hugepage_range(vma, vma->vm_start + v_offset, 393 vma->vm_end, NULL); 394 } 395 } 396 397 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset) 398 { 399 pgoff_t pgoff; 400 struct address_space *mapping = inode->i_mapping; 401 struct hstate *h = hstate_inode(inode); 402 403 BUG_ON(offset & ~huge_page_mask(h)); 404 pgoff = offset >> PAGE_SHIFT; 405 406 i_size_write(inode, offset); 407 mutex_lock(&mapping->i_mmap_mutex); 408 if (!RB_EMPTY_ROOT(&mapping->i_mmap)) 409 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff); 410 mutex_unlock(&mapping->i_mmap_mutex); 411 truncate_hugepages(inode, offset); 412 return 0; 413 } 414 415 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr) 416 { 417 struct inode *inode = dentry->d_inode; 418 struct hstate *h = hstate_inode(inode); 419 int error; 420 unsigned int ia_valid = attr->ia_valid; 421 422 BUG_ON(!inode); 423 424 error = inode_change_ok(inode, attr); 425 if (error) 426 return error; 427 428 if (ia_valid & ATTR_SIZE) { 429 error = -EINVAL; 430 if (attr->ia_size & ~huge_page_mask(h)) 431 return -EINVAL; 432 error = hugetlb_vmtruncate(inode, attr->ia_size); 433 if (error) 434 return error; 435 } 436 437 setattr_copy(inode, attr); 438 mark_inode_dirty(inode); 439 return 0; 440 } 441 442 static struct inode *hugetlbfs_get_root(struct super_block *sb, 443 struct hugetlbfs_config *config) 444 { 445 struct inode *inode; 446 447 inode = new_inode(sb); 448 if (inode) { 449 struct hugetlbfs_inode_info *info; 450 inode->i_ino = get_next_ino(); 451 inode->i_mode = S_IFDIR | config->mode; 452 inode->i_uid = config->uid; 453 inode->i_gid = config->gid; 454 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 455 info = HUGETLBFS_I(inode); 456 mpol_shared_policy_init(&info->policy, NULL); 457 inode->i_op = &hugetlbfs_dir_inode_operations; 458 inode->i_fop = &simple_dir_operations; 459 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 460 inc_nlink(inode); 461 lockdep_annotate_inode_mutex_key(inode); 462 } 463 return inode; 464 } 465 466 static struct inode *hugetlbfs_get_inode(struct super_block *sb, 467 struct inode *dir, 468 umode_t mode, dev_t dev) 469 { 470 struct inode *inode; 471 472 inode = new_inode(sb); 473 if (inode) { 474 struct hugetlbfs_inode_info *info; 475 inode->i_ino = get_next_ino(); 476 inode_init_owner(inode, dir, mode); 477 inode->i_mapping->a_ops = &hugetlbfs_aops; 478 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info; 479 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 480 INIT_LIST_HEAD(&inode->i_mapping->private_list); 481 info = HUGETLBFS_I(inode); 482 /* 483 * The policy is initialized here even if we are creating a 484 * private inode because initialization simply creates an 485 * an empty rb tree and calls spin_lock_init(), later when we 486 * call mpol_free_shared_policy() it will just return because 487 * the rb tree will still be empty. 488 */ 489 mpol_shared_policy_init(&info->policy, NULL); 490 switch (mode & S_IFMT) { 491 default: 492 init_special_inode(inode, mode, dev); 493 break; 494 case S_IFREG: 495 inode->i_op = &hugetlbfs_inode_operations; 496 inode->i_fop = &hugetlbfs_file_operations; 497 break; 498 case S_IFDIR: 499 inode->i_op = &hugetlbfs_dir_inode_operations; 500 inode->i_fop = &simple_dir_operations; 501 502 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 503 inc_nlink(inode); 504 break; 505 case S_IFLNK: 506 inode->i_op = &page_symlink_inode_operations; 507 break; 508 } 509 lockdep_annotate_inode_mutex_key(inode); 510 } 511 return inode; 512 } 513 514 /* 515 * File creation. Allocate an inode, and we're done.. 516 */ 517 static int hugetlbfs_mknod(struct inode *dir, 518 struct dentry *dentry, umode_t mode, dev_t dev) 519 { 520 struct inode *inode; 521 int error = -ENOSPC; 522 523 inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev); 524 if (inode) { 525 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 526 d_instantiate(dentry, inode); 527 dget(dentry); /* Extra count - pin the dentry in core */ 528 error = 0; 529 } 530 return error; 531 } 532 533 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 534 { 535 int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0); 536 if (!retval) 537 inc_nlink(dir); 538 return retval; 539 } 540 541 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) 542 { 543 return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0); 544 } 545 546 static int hugetlbfs_symlink(struct inode *dir, 547 struct dentry *dentry, const char *symname) 548 { 549 struct inode *inode; 550 int error = -ENOSPC; 551 552 inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0); 553 if (inode) { 554 int l = strlen(symname)+1; 555 error = page_symlink(inode, symname, l); 556 if (!error) { 557 d_instantiate(dentry, inode); 558 dget(dentry); 559 } else 560 iput(inode); 561 } 562 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 563 564 return error; 565 } 566 567 /* 568 * mark the head page dirty 569 */ 570 static int hugetlbfs_set_page_dirty(struct page *page) 571 { 572 struct page *head = compound_head(page); 573 574 SetPageDirty(head); 575 return 0; 576 } 577 578 static int hugetlbfs_migrate_page(struct address_space *mapping, 579 struct page *newpage, struct page *page, 580 enum migrate_mode mode) 581 { 582 int rc; 583 584 rc = migrate_huge_page_move_mapping(mapping, newpage, page); 585 if (rc != MIGRATEPAGE_SUCCESS) 586 return rc; 587 migrate_page_copy(newpage, page); 588 589 return MIGRATEPAGE_SUCCESS; 590 } 591 592 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf) 593 { 594 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb); 595 struct hstate *h = hstate_inode(dentry->d_inode); 596 597 buf->f_type = HUGETLBFS_MAGIC; 598 buf->f_bsize = huge_page_size(h); 599 if (sbinfo) { 600 spin_lock(&sbinfo->stat_lock); 601 /* If no limits set, just report 0 for max/free/used 602 * blocks, like simple_statfs() */ 603 if (sbinfo->spool) { 604 long free_pages; 605 606 spin_lock(&sbinfo->spool->lock); 607 buf->f_blocks = sbinfo->spool->max_hpages; 608 free_pages = sbinfo->spool->max_hpages 609 - sbinfo->spool->used_hpages; 610 buf->f_bavail = buf->f_bfree = free_pages; 611 spin_unlock(&sbinfo->spool->lock); 612 buf->f_files = sbinfo->max_inodes; 613 buf->f_ffree = sbinfo->free_inodes; 614 } 615 spin_unlock(&sbinfo->stat_lock); 616 } 617 buf->f_namelen = NAME_MAX; 618 return 0; 619 } 620 621 static void hugetlbfs_put_super(struct super_block *sb) 622 { 623 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb); 624 625 if (sbi) { 626 sb->s_fs_info = NULL; 627 628 if (sbi->spool) 629 hugepage_put_subpool(sbi->spool); 630 631 kfree(sbi); 632 } 633 } 634 635 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo) 636 { 637 if (sbinfo->free_inodes >= 0) { 638 spin_lock(&sbinfo->stat_lock); 639 if (unlikely(!sbinfo->free_inodes)) { 640 spin_unlock(&sbinfo->stat_lock); 641 return 0; 642 } 643 sbinfo->free_inodes--; 644 spin_unlock(&sbinfo->stat_lock); 645 } 646 647 return 1; 648 } 649 650 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo) 651 { 652 if (sbinfo->free_inodes >= 0) { 653 spin_lock(&sbinfo->stat_lock); 654 sbinfo->free_inodes++; 655 spin_unlock(&sbinfo->stat_lock); 656 } 657 } 658 659 660 static struct kmem_cache *hugetlbfs_inode_cachep; 661 662 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb) 663 { 664 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb); 665 struct hugetlbfs_inode_info *p; 666 667 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo))) 668 return NULL; 669 p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL); 670 if (unlikely(!p)) { 671 hugetlbfs_inc_free_inodes(sbinfo); 672 return NULL; 673 } 674 return &p->vfs_inode; 675 } 676 677 static void hugetlbfs_i_callback(struct rcu_head *head) 678 { 679 struct inode *inode = container_of(head, struct inode, i_rcu); 680 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode)); 681 } 682 683 static void hugetlbfs_destroy_inode(struct inode *inode) 684 { 685 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb)); 686 mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy); 687 call_rcu(&inode->i_rcu, hugetlbfs_i_callback); 688 } 689 690 static const struct address_space_operations hugetlbfs_aops = { 691 .write_begin = hugetlbfs_write_begin, 692 .write_end = hugetlbfs_write_end, 693 .set_page_dirty = hugetlbfs_set_page_dirty, 694 .migratepage = hugetlbfs_migrate_page, 695 }; 696 697 698 static void init_once(void *foo) 699 { 700 struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo; 701 702 inode_init_once(&ei->vfs_inode); 703 } 704 705 const struct file_operations hugetlbfs_file_operations = { 706 .read = hugetlbfs_read, 707 .mmap = hugetlbfs_file_mmap, 708 .fsync = noop_fsync, 709 .get_unmapped_area = hugetlb_get_unmapped_area, 710 .llseek = default_llseek, 711 }; 712 713 static const struct inode_operations hugetlbfs_dir_inode_operations = { 714 .create = hugetlbfs_create, 715 .lookup = simple_lookup, 716 .link = simple_link, 717 .unlink = simple_unlink, 718 .symlink = hugetlbfs_symlink, 719 .mkdir = hugetlbfs_mkdir, 720 .rmdir = simple_rmdir, 721 .mknod = hugetlbfs_mknod, 722 .rename = simple_rename, 723 .setattr = hugetlbfs_setattr, 724 }; 725 726 static const struct inode_operations hugetlbfs_inode_operations = { 727 .setattr = hugetlbfs_setattr, 728 }; 729 730 static const struct super_operations hugetlbfs_ops = { 731 .alloc_inode = hugetlbfs_alloc_inode, 732 .destroy_inode = hugetlbfs_destroy_inode, 733 .evict_inode = hugetlbfs_evict_inode, 734 .statfs = hugetlbfs_statfs, 735 .put_super = hugetlbfs_put_super, 736 .show_options = generic_show_options, 737 }; 738 739 static int 740 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig) 741 { 742 char *p, *rest; 743 substring_t args[MAX_OPT_ARGS]; 744 int option; 745 unsigned long long size = 0; 746 enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE; 747 748 if (!options) 749 return 0; 750 751 while ((p = strsep(&options, ",")) != NULL) { 752 int token; 753 if (!*p) 754 continue; 755 756 token = match_token(p, tokens, args); 757 switch (token) { 758 case Opt_uid: 759 if (match_int(&args[0], &option)) 760 goto bad_val; 761 pconfig->uid = make_kuid(current_user_ns(), option); 762 if (!uid_valid(pconfig->uid)) 763 goto bad_val; 764 break; 765 766 case Opt_gid: 767 if (match_int(&args[0], &option)) 768 goto bad_val; 769 pconfig->gid = make_kgid(current_user_ns(), option); 770 if (!gid_valid(pconfig->gid)) 771 goto bad_val; 772 break; 773 774 case Opt_mode: 775 if (match_octal(&args[0], &option)) 776 goto bad_val; 777 pconfig->mode = option & 01777U; 778 break; 779 780 case Opt_size: { 781 /* memparse() will accept a K/M/G without a digit */ 782 if (!isdigit(*args[0].from)) 783 goto bad_val; 784 size = memparse(args[0].from, &rest); 785 setsize = SIZE_STD; 786 if (*rest == '%') 787 setsize = SIZE_PERCENT; 788 break; 789 } 790 791 case Opt_nr_inodes: 792 /* memparse() will accept a K/M/G without a digit */ 793 if (!isdigit(*args[0].from)) 794 goto bad_val; 795 pconfig->nr_inodes = memparse(args[0].from, &rest); 796 break; 797 798 case Opt_pagesize: { 799 unsigned long ps; 800 ps = memparse(args[0].from, &rest); 801 pconfig->hstate = size_to_hstate(ps); 802 if (!pconfig->hstate) { 803 printk(KERN_ERR 804 "hugetlbfs: Unsupported page size %lu MB\n", 805 ps >> 20); 806 return -EINVAL; 807 } 808 break; 809 } 810 811 default: 812 printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n", 813 p); 814 return -EINVAL; 815 break; 816 } 817 } 818 819 /* Do size after hstate is set up */ 820 if (setsize > NO_SIZE) { 821 struct hstate *h = pconfig->hstate; 822 if (setsize == SIZE_PERCENT) { 823 size <<= huge_page_shift(h); 824 size *= h->max_huge_pages; 825 do_div(size, 100); 826 } 827 pconfig->nr_blocks = (size >> huge_page_shift(h)); 828 } 829 830 return 0; 831 832 bad_val: 833 printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n", 834 args[0].from, p); 835 return -EINVAL; 836 } 837 838 static int 839 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent) 840 { 841 int ret; 842 struct hugetlbfs_config config; 843 struct hugetlbfs_sb_info *sbinfo; 844 845 save_mount_options(sb, data); 846 847 config.nr_blocks = -1; /* No limit on size by default */ 848 config.nr_inodes = -1; /* No limit on number of inodes by default */ 849 config.uid = current_fsuid(); 850 config.gid = current_fsgid(); 851 config.mode = 0755; 852 config.hstate = &default_hstate; 853 ret = hugetlbfs_parse_options(data, &config); 854 if (ret) 855 return ret; 856 857 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL); 858 if (!sbinfo) 859 return -ENOMEM; 860 sb->s_fs_info = sbinfo; 861 sbinfo->hstate = config.hstate; 862 spin_lock_init(&sbinfo->stat_lock); 863 sbinfo->max_inodes = config.nr_inodes; 864 sbinfo->free_inodes = config.nr_inodes; 865 sbinfo->spool = NULL; 866 if (config.nr_blocks != -1) { 867 sbinfo->spool = hugepage_new_subpool(config.nr_blocks); 868 if (!sbinfo->spool) 869 goto out_free; 870 } 871 sb->s_maxbytes = MAX_LFS_FILESIZE; 872 sb->s_blocksize = huge_page_size(config.hstate); 873 sb->s_blocksize_bits = huge_page_shift(config.hstate); 874 sb->s_magic = HUGETLBFS_MAGIC; 875 sb->s_op = &hugetlbfs_ops; 876 sb->s_time_gran = 1; 877 sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config)); 878 if (!sb->s_root) 879 goto out_free; 880 return 0; 881 out_free: 882 if (sbinfo->spool) 883 kfree(sbinfo->spool); 884 kfree(sbinfo); 885 return -ENOMEM; 886 } 887 888 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type, 889 int flags, const char *dev_name, void *data) 890 { 891 return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super); 892 } 893 894 static struct file_system_type hugetlbfs_fs_type = { 895 .name = "hugetlbfs", 896 .mount = hugetlbfs_mount, 897 .kill_sb = kill_litter_super, 898 }; 899 900 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE]; 901 902 static int can_do_hugetlb_shm(void) 903 { 904 kgid_t shm_group; 905 shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group); 906 return capable(CAP_IPC_LOCK) || in_group_p(shm_group); 907 } 908 909 static int get_hstate_idx(int page_size_log) 910 { 911 struct hstate *h; 912 913 if (!page_size_log) 914 return default_hstate_idx; 915 h = size_to_hstate(1 << page_size_log); 916 if (!h) 917 return -1; 918 return h - hstates; 919 } 920 921 struct file *hugetlb_file_setup(const char *name, unsigned long addr, 922 size_t size, vm_flags_t acctflag, 923 struct user_struct **user, 924 int creat_flags, int page_size_log) 925 { 926 int error = -ENOMEM; 927 struct file *file; 928 struct inode *inode; 929 struct path path; 930 struct dentry *root; 931 struct qstr quick_string; 932 struct hstate *hstate; 933 unsigned long num_pages; 934 int hstate_idx; 935 936 hstate_idx = get_hstate_idx(page_size_log); 937 if (hstate_idx < 0) 938 return ERR_PTR(-ENODEV); 939 940 *user = NULL; 941 if (!hugetlbfs_vfsmount[hstate_idx]) 942 return ERR_PTR(-ENOENT); 943 944 if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) { 945 *user = current_user(); 946 if (user_shm_lock(size, *user)) { 947 task_lock(current); 948 printk_once(KERN_WARNING 949 "%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n", 950 current->comm, current->pid); 951 task_unlock(current); 952 } else { 953 *user = NULL; 954 return ERR_PTR(-EPERM); 955 } 956 } 957 958 root = hugetlbfs_vfsmount[hstate_idx]->mnt_root; 959 quick_string.name = name; 960 quick_string.len = strlen(quick_string.name); 961 quick_string.hash = 0; 962 path.dentry = d_alloc(root, &quick_string); 963 if (!path.dentry) 964 goto out_shm_unlock; 965 966 path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]); 967 error = -ENOSPC; 968 inode = hugetlbfs_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0); 969 if (!inode) 970 goto out_dentry; 971 972 hstate = hstate_inode(inode); 973 size += addr & ~huge_page_mask(hstate); 974 num_pages = ALIGN(size, huge_page_size(hstate)) >> 975 huge_page_shift(hstate); 976 error = -ENOMEM; 977 if (hugetlb_reserve_pages(inode, 0, num_pages, NULL, acctflag)) 978 goto out_inode; 979 980 d_instantiate(path.dentry, inode); 981 inode->i_size = size; 982 clear_nlink(inode); 983 984 error = -ENFILE; 985 file = alloc_file(&path, FMODE_WRITE | FMODE_READ, 986 &hugetlbfs_file_operations); 987 if (!file) 988 goto out_dentry; /* inode is already attached */ 989 990 return file; 991 992 out_inode: 993 iput(inode); 994 out_dentry: 995 path_put(&path); 996 out_shm_unlock: 997 if (*user) { 998 user_shm_unlock(size, *user); 999 *user = NULL; 1000 } 1001 return ERR_PTR(error); 1002 } 1003 1004 static int __init init_hugetlbfs_fs(void) 1005 { 1006 struct hstate *h; 1007 int error; 1008 int i; 1009 1010 error = bdi_init(&hugetlbfs_backing_dev_info); 1011 if (error) 1012 return error; 1013 1014 error = -ENOMEM; 1015 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache", 1016 sizeof(struct hugetlbfs_inode_info), 1017 0, 0, init_once); 1018 if (hugetlbfs_inode_cachep == NULL) 1019 goto out2; 1020 1021 error = register_filesystem(&hugetlbfs_fs_type); 1022 if (error) 1023 goto out; 1024 1025 i = 0; 1026 for_each_hstate(h) { 1027 char buf[50]; 1028 unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10); 1029 1030 snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb); 1031 hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type, 1032 buf); 1033 1034 if (IS_ERR(hugetlbfs_vfsmount[i])) { 1035 pr_err("hugetlb: Cannot mount internal hugetlbfs for " 1036 "page size %uK", ps_kb); 1037 error = PTR_ERR(hugetlbfs_vfsmount[i]); 1038 hugetlbfs_vfsmount[i] = NULL; 1039 } 1040 i++; 1041 } 1042 /* Non default hstates are optional */ 1043 if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx])) 1044 return 0; 1045 1046 out: 1047 kmem_cache_destroy(hugetlbfs_inode_cachep); 1048 out2: 1049 bdi_destroy(&hugetlbfs_backing_dev_info); 1050 return error; 1051 } 1052 1053 static void __exit exit_hugetlbfs_fs(void) 1054 { 1055 struct hstate *h; 1056 int i; 1057 1058 1059 /* 1060 * Make sure all delayed rcu free inodes are flushed before we 1061 * destroy cache. 1062 */ 1063 rcu_barrier(); 1064 kmem_cache_destroy(hugetlbfs_inode_cachep); 1065 i = 0; 1066 for_each_hstate(h) 1067 kern_unmount(hugetlbfs_vfsmount[i++]); 1068 unregister_filesystem(&hugetlbfs_fs_type); 1069 bdi_destroy(&hugetlbfs_backing_dev_info); 1070 } 1071 1072 module_init(init_hugetlbfs_fs) 1073 module_exit(exit_hugetlbfs_fs) 1074 1075 MODULE_LICENSE("GPL"); 1076