1 /* 2 * hugetlbpage-backed filesystem. Based on ramfs. 3 * 4 * Nadia Yvette Chambers, 2002 5 * 6 * Copyright (C) 2002 Linus Torvalds. 7 */ 8 9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 10 11 #include <linux/module.h> 12 #include <linux/thread_info.h> 13 #include <asm/current.h> 14 #include <linux/sched.h> /* remove ASAP */ 15 #include <linux/fs.h> 16 #include <linux/mount.h> 17 #include <linux/file.h> 18 #include <linux/kernel.h> 19 #include <linux/writeback.h> 20 #include <linux/pagemap.h> 21 #include <linux/highmem.h> 22 #include <linux/init.h> 23 #include <linux/string.h> 24 #include <linux/capability.h> 25 #include <linux/ctype.h> 26 #include <linux/backing-dev.h> 27 #include <linux/hugetlb.h> 28 #include <linux/pagevec.h> 29 #include <linux/parser.h> 30 #include <linux/mman.h> 31 #include <linux/slab.h> 32 #include <linux/dnotify.h> 33 #include <linux/statfs.h> 34 #include <linux/security.h> 35 #include <linux/magic.h> 36 #include <linux/migrate.h> 37 38 #include <asm/uaccess.h> 39 40 static const struct super_operations hugetlbfs_ops; 41 static const struct address_space_operations hugetlbfs_aops; 42 const struct file_operations hugetlbfs_file_operations; 43 static const struct inode_operations hugetlbfs_dir_inode_operations; 44 static const struct inode_operations hugetlbfs_inode_operations; 45 46 struct hugetlbfs_config { 47 kuid_t uid; 48 kgid_t gid; 49 umode_t mode; 50 long nr_blocks; 51 long nr_inodes; 52 struct hstate *hstate; 53 }; 54 55 struct hugetlbfs_inode_info { 56 struct shared_policy policy; 57 struct inode vfs_inode; 58 }; 59 60 static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode) 61 { 62 return container_of(inode, struct hugetlbfs_inode_info, vfs_inode); 63 } 64 65 int sysctl_hugetlb_shm_group; 66 67 enum { 68 Opt_size, Opt_nr_inodes, 69 Opt_mode, Opt_uid, Opt_gid, 70 Opt_pagesize, 71 Opt_err, 72 }; 73 74 static const match_table_t tokens = { 75 {Opt_size, "size=%s"}, 76 {Opt_nr_inodes, "nr_inodes=%s"}, 77 {Opt_mode, "mode=%o"}, 78 {Opt_uid, "uid=%u"}, 79 {Opt_gid, "gid=%u"}, 80 {Opt_pagesize, "pagesize=%s"}, 81 {Opt_err, NULL}, 82 }; 83 84 static void huge_pagevec_release(struct pagevec *pvec) 85 { 86 int i; 87 88 for (i = 0; i < pagevec_count(pvec); ++i) 89 put_page(pvec->pages[i]); 90 91 pagevec_reinit(pvec); 92 } 93 94 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma) 95 { 96 struct inode *inode = file_inode(file); 97 loff_t len, vma_len; 98 int ret; 99 struct hstate *h = hstate_file(file); 100 101 /* 102 * vma address alignment (but not the pgoff alignment) has 103 * already been checked by prepare_hugepage_range. If you add 104 * any error returns here, do so after setting VM_HUGETLB, so 105 * is_vm_hugetlb_page tests below unmap_region go the right 106 * way when do_mmap_pgoff unwinds (may be important on powerpc 107 * and ia64). 108 */ 109 vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND; 110 vma->vm_ops = &hugetlb_vm_ops; 111 112 if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT)) 113 return -EINVAL; 114 115 vma_len = (loff_t)(vma->vm_end - vma->vm_start); 116 117 mutex_lock(&inode->i_mutex); 118 file_accessed(file); 119 120 ret = -ENOMEM; 121 len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); 122 123 if (hugetlb_reserve_pages(inode, 124 vma->vm_pgoff >> huge_page_order(h), 125 len >> huge_page_shift(h), vma, 126 vma->vm_flags)) 127 goto out; 128 129 ret = 0; 130 hugetlb_prefault_arch_hook(vma->vm_mm); 131 if (vma->vm_flags & VM_WRITE && inode->i_size < len) 132 inode->i_size = len; 133 out: 134 mutex_unlock(&inode->i_mutex); 135 136 return ret; 137 } 138 139 /* 140 * Called under down_write(mmap_sem). 141 */ 142 143 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA 144 static unsigned long 145 hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 146 unsigned long len, unsigned long pgoff, unsigned long flags) 147 { 148 struct mm_struct *mm = current->mm; 149 struct vm_area_struct *vma; 150 struct hstate *h = hstate_file(file); 151 struct vm_unmapped_area_info info; 152 153 if (len & ~huge_page_mask(h)) 154 return -EINVAL; 155 if (len > TASK_SIZE) 156 return -ENOMEM; 157 158 if (flags & MAP_FIXED) { 159 if (prepare_hugepage_range(file, addr, len)) 160 return -EINVAL; 161 return addr; 162 } 163 164 if (addr) { 165 addr = ALIGN(addr, huge_page_size(h)); 166 vma = find_vma(mm, addr); 167 if (TASK_SIZE - len >= addr && 168 (!vma || addr + len <= vma->vm_start)) 169 return addr; 170 } 171 172 info.flags = 0; 173 info.length = len; 174 info.low_limit = TASK_UNMAPPED_BASE; 175 info.high_limit = TASK_SIZE; 176 info.align_mask = PAGE_MASK & ~huge_page_mask(h); 177 info.align_offset = 0; 178 return vm_unmapped_area(&info); 179 } 180 #endif 181 182 static int 183 hugetlbfs_read_actor(struct page *page, unsigned long offset, 184 char __user *buf, unsigned long count, 185 unsigned long size) 186 { 187 char *kaddr; 188 unsigned long left, copied = 0; 189 int i, chunksize; 190 191 if (size > count) 192 size = count; 193 194 /* Find which 4k chunk and offset with in that chunk */ 195 i = offset >> PAGE_CACHE_SHIFT; 196 offset = offset & ~PAGE_CACHE_MASK; 197 198 while (size) { 199 chunksize = PAGE_CACHE_SIZE; 200 if (offset) 201 chunksize -= offset; 202 if (chunksize > size) 203 chunksize = size; 204 kaddr = kmap(&page[i]); 205 left = __copy_to_user(buf, kaddr + offset, chunksize); 206 kunmap(&page[i]); 207 if (left) { 208 copied += (chunksize - left); 209 break; 210 } 211 offset = 0; 212 size -= chunksize; 213 buf += chunksize; 214 copied += chunksize; 215 i++; 216 } 217 return copied ? copied : -EFAULT; 218 } 219 220 /* 221 * Support for read() - Find the page attached to f_mapping and copy out the 222 * data. Its *very* similar to do_generic_mapping_read(), we can't use that 223 * since it has PAGE_CACHE_SIZE assumptions. 224 */ 225 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf, 226 size_t len, loff_t *ppos) 227 { 228 struct hstate *h = hstate_file(filp); 229 struct address_space *mapping = filp->f_mapping; 230 struct inode *inode = mapping->host; 231 unsigned long index = *ppos >> huge_page_shift(h); 232 unsigned long offset = *ppos & ~huge_page_mask(h); 233 unsigned long end_index; 234 loff_t isize; 235 ssize_t retval = 0; 236 237 /* validate length */ 238 if (len == 0) 239 goto out; 240 241 for (;;) { 242 struct page *page; 243 unsigned long nr, ret; 244 int ra; 245 246 /* nr is the maximum number of bytes to copy from this page */ 247 nr = huge_page_size(h); 248 isize = i_size_read(inode); 249 if (!isize) 250 goto out; 251 end_index = (isize - 1) >> huge_page_shift(h); 252 if (index >= end_index) { 253 if (index > end_index) 254 goto out; 255 nr = ((isize - 1) & ~huge_page_mask(h)) + 1; 256 if (nr <= offset) 257 goto out; 258 } 259 nr = nr - offset; 260 261 /* Find the page */ 262 page = find_lock_page(mapping, index); 263 if (unlikely(page == NULL)) { 264 /* 265 * We have a HOLE, zero out the user-buffer for the 266 * length of the hole or request. 267 */ 268 ret = len < nr ? len : nr; 269 if (clear_user(buf, ret)) 270 ra = -EFAULT; 271 else 272 ra = 0; 273 } else { 274 unlock_page(page); 275 276 /* 277 * We have the page, copy it to user space buffer. 278 */ 279 ra = hugetlbfs_read_actor(page, offset, buf, len, nr); 280 ret = ra; 281 page_cache_release(page); 282 } 283 if (ra < 0) { 284 if (retval == 0) 285 retval = ra; 286 goto out; 287 } 288 289 offset += ret; 290 retval += ret; 291 len -= ret; 292 index += offset >> huge_page_shift(h); 293 offset &= ~huge_page_mask(h); 294 295 /* short read or no more work */ 296 if ((ret != nr) || (len == 0)) 297 break; 298 } 299 out: 300 *ppos = ((loff_t)index << huge_page_shift(h)) + offset; 301 return retval; 302 } 303 304 static int hugetlbfs_write_begin(struct file *file, 305 struct address_space *mapping, 306 loff_t pos, unsigned len, unsigned flags, 307 struct page **pagep, void **fsdata) 308 { 309 return -EINVAL; 310 } 311 312 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping, 313 loff_t pos, unsigned len, unsigned copied, 314 struct page *page, void *fsdata) 315 { 316 BUG(); 317 return -EINVAL; 318 } 319 320 static void truncate_huge_page(struct page *page) 321 { 322 cancel_dirty_page(page, /* No IO accounting for huge pages? */0); 323 ClearPageUptodate(page); 324 delete_from_page_cache(page); 325 } 326 327 static void truncate_hugepages(struct inode *inode, loff_t lstart) 328 { 329 struct hstate *h = hstate_inode(inode); 330 struct address_space *mapping = &inode->i_data; 331 const pgoff_t start = lstart >> huge_page_shift(h); 332 struct pagevec pvec; 333 pgoff_t next; 334 int i, freed = 0; 335 336 pagevec_init(&pvec, 0); 337 next = start; 338 while (1) { 339 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { 340 if (next == start) 341 break; 342 next = start; 343 continue; 344 } 345 346 for (i = 0; i < pagevec_count(&pvec); ++i) { 347 struct page *page = pvec.pages[i]; 348 349 lock_page(page); 350 if (page->index > next) 351 next = page->index; 352 ++next; 353 truncate_huge_page(page); 354 unlock_page(page); 355 freed++; 356 } 357 huge_pagevec_release(&pvec); 358 } 359 BUG_ON(!lstart && mapping->nrpages); 360 hugetlb_unreserve_pages(inode, start, freed); 361 } 362 363 static void hugetlbfs_evict_inode(struct inode *inode) 364 { 365 struct resv_map *resv_map; 366 367 truncate_hugepages(inode, 0); 368 resv_map = (struct resv_map *)inode->i_mapping->private_data; 369 /* root inode doesn't have the resv_map, so we should check it */ 370 if (resv_map) 371 resv_map_release(&resv_map->refs); 372 clear_inode(inode); 373 } 374 375 static inline void 376 hugetlb_vmtruncate_list(struct rb_root *root, pgoff_t pgoff) 377 { 378 struct vm_area_struct *vma; 379 380 vma_interval_tree_foreach(vma, root, pgoff, ULONG_MAX) { 381 unsigned long v_offset; 382 383 /* 384 * Can the expression below overflow on 32-bit arches? 385 * No, because the interval tree returns us only those vmas 386 * which overlap the truncated area starting at pgoff, 387 * and no vma on a 32-bit arch can span beyond the 4GB. 388 */ 389 if (vma->vm_pgoff < pgoff) 390 v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT; 391 else 392 v_offset = 0; 393 394 unmap_hugepage_range(vma, vma->vm_start + v_offset, 395 vma->vm_end, NULL); 396 } 397 } 398 399 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset) 400 { 401 pgoff_t pgoff; 402 struct address_space *mapping = inode->i_mapping; 403 struct hstate *h = hstate_inode(inode); 404 405 BUG_ON(offset & ~huge_page_mask(h)); 406 pgoff = offset >> PAGE_SHIFT; 407 408 i_size_write(inode, offset); 409 i_mmap_lock_write(mapping); 410 if (!RB_EMPTY_ROOT(&mapping->i_mmap)) 411 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff); 412 i_mmap_unlock_write(mapping); 413 truncate_hugepages(inode, offset); 414 return 0; 415 } 416 417 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr) 418 { 419 struct inode *inode = dentry->d_inode; 420 struct hstate *h = hstate_inode(inode); 421 int error; 422 unsigned int ia_valid = attr->ia_valid; 423 424 BUG_ON(!inode); 425 426 error = inode_change_ok(inode, attr); 427 if (error) 428 return error; 429 430 if (ia_valid & ATTR_SIZE) { 431 error = -EINVAL; 432 if (attr->ia_size & ~huge_page_mask(h)) 433 return -EINVAL; 434 error = hugetlb_vmtruncate(inode, attr->ia_size); 435 if (error) 436 return error; 437 } 438 439 setattr_copy(inode, attr); 440 mark_inode_dirty(inode); 441 return 0; 442 } 443 444 static struct inode *hugetlbfs_get_root(struct super_block *sb, 445 struct hugetlbfs_config *config) 446 { 447 struct inode *inode; 448 449 inode = new_inode(sb); 450 if (inode) { 451 struct hugetlbfs_inode_info *info; 452 inode->i_ino = get_next_ino(); 453 inode->i_mode = S_IFDIR | config->mode; 454 inode->i_uid = config->uid; 455 inode->i_gid = config->gid; 456 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 457 info = HUGETLBFS_I(inode); 458 mpol_shared_policy_init(&info->policy, NULL); 459 inode->i_op = &hugetlbfs_dir_inode_operations; 460 inode->i_fop = &simple_dir_operations; 461 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 462 inc_nlink(inode); 463 lockdep_annotate_inode_mutex_key(inode); 464 } 465 return inode; 466 } 467 468 /* 469 * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never 470 * be taken from reclaim -- unlike regular filesystems. This needs an 471 * annotation because huge_pmd_share() does an allocation under 472 * i_mmap_rwsem. 473 */ 474 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key; 475 476 static struct inode *hugetlbfs_get_inode(struct super_block *sb, 477 struct inode *dir, 478 umode_t mode, dev_t dev) 479 { 480 struct inode *inode; 481 struct resv_map *resv_map; 482 483 resv_map = resv_map_alloc(); 484 if (!resv_map) 485 return NULL; 486 487 inode = new_inode(sb); 488 if (inode) { 489 struct hugetlbfs_inode_info *info; 490 inode->i_ino = get_next_ino(); 491 inode_init_owner(inode, dir, mode); 492 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem, 493 &hugetlbfs_i_mmap_rwsem_key); 494 inode->i_mapping->a_ops = &hugetlbfs_aops; 495 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 496 inode->i_mapping->private_data = resv_map; 497 info = HUGETLBFS_I(inode); 498 /* 499 * The policy is initialized here even if we are creating a 500 * private inode because initialization simply creates an 501 * an empty rb tree and calls spin_lock_init(), later when we 502 * call mpol_free_shared_policy() it will just return because 503 * the rb tree will still be empty. 504 */ 505 mpol_shared_policy_init(&info->policy, NULL); 506 switch (mode & S_IFMT) { 507 default: 508 init_special_inode(inode, mode, dev); 509 break; 510 case S_IFREG: 511 inode->i_op = &hugetlbfs_inode_operations; 512 inode->i_fop = &hugetlbfs_file_operations; 513 break; 514 case S_IFDIR: 515 inode->i_op = &hugetlbfs_dir_inode_operations; 516 inode->i_fop = &simple_dir_operations; 517 518 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 519 inc_nlink(inode); 520 break; 521 case S_IFLNK: 522 inode->i_op = &page_symlink_inode_operations; 523 break; 524 } 525 lockdep_annotate_inode_mutex_key(inode); 526 } else 527 kref_put(&resv_map->refs, resv_map_release); 528 529 return inode; 530 } 531 532 /* 533 * File creation. Allocate an inode, and we're done.. 534 */ 535 static int hugetlbfs_mknod(struct inode *dir, 536 struct dentry *dentry, umode_t mode, dev_t dev) 537 { 538 struct inode *inode; 539 int error = -ENOSPC; 540 541 inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev); 542 if (inode) { 543 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 544 d_instantiate(dentry, inode); 545 dget(dentry); /* Extra count - pin the dentry in core */ 546 error = 0; 547 } 548 return error; 549 } 550 551 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 552 { 553 int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0); 554 if (!retval) 555 inc_nlink(dir); 556 return retval; 557 } 558 559 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) 560 { 561 return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0); 562 } 563 564 static int hugetlbfs_symlink(struct inode *dir, 565 struct dentry *dentry, const char *symname) 566 { 567 struct inode *inode; 568 int error = -ENOSPC; 569 570 inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0); 571 if (inode) { 572 int l = strlen(symname)+1; 573 error = page_symlink(inode, symname, l); 574 if (!error) { 575 d_instantiate(dentry, inode); 576 dget(dentry); 577 } else 578 iput(inode); 579 } 580 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 581 582 return error; 583 } 584 585 /* 586 * mark the head page dirty 587 */ 588 static int hugetlbfs_set_page_dirty(struct page *page) 589 { 590 struct page *head = compound_head(page); 591 592 SetPageDirty(head); 593 return 0; 594 } 595 596 static int hugetlbfs_migrate_page(struct address_space *mapping, 597 struct page *newpage, struct page *page, 598 enum migrate_mode mode) 599 { 600 int rc; 601 602 rc = migrate_huge_page_move_mapping(mapping, newpage, page); 603 if (rc != MIGRATEPAGE_SUCCESS) 604 return rc; 605 migrate_page_copy(newpage, page); 606 607 return MIGRATEPAGE_SUCCESS; 608 } 609 610 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf) 611 { 612 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb); 613 struct hstate *h = hstate_inode(dentry->d_inode); 614 615 buf->f_type = HUGETLBFS_MAGIC; 616 buf->f_bsize = huge_page_size(h); 617 if (sbinfo) { 618 spin_lock(&sbinfo->stat_lock); 619 /* If no limits set, just report 0 for max/free/used 620 * blocks, like simple_statfs() */ 621 if (sbinfo->spool) { 622 long free_pages; 623 624 spin_lock(&sbinfo->spool->lock); 625 buf->f_blocks = sbinfo->spool->max_hpages; 626 free_pages = sbinfo->spool->max_hpages 627 - sbinfo->spool->used_hpages; 628 buf->f_bavail = buf->f_bfree = free_pages; 629 spin_unlock(&sbinfo->spool->lock); 630 buf->f_files = sbinfo->max_inodes; 631 buf->f_ffree = sbinfo->free_inodes; 632 } 633 spin_unlock(&sbinfo->stat_lock); 634 } 635 buf->f_namelen = NAME_MAX; 636 return 0; 637 } 638 639 static void hugetlbfs_put_super(struct super_block *sb) 640 { 641 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb); 642 643 if (sbi) { 644 sb->s_fs_info = NULL; 645 646 if (sbi->spool) 647 hugepage_put_subpool(sbi->spool); 648 649 kfree(sbi); 650 } 651 } 652 653 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo) 654 { 655 if (sbinfo->free_inodes >= 0) { 656 spin_lock(&sbinfo->stat_lock); 657 if (unlikely(!sbinfo->free_inodes)) { 658 spin_unlock(&sbinfo->stat_lock); 659 return 0; 660 } 661 sbinfo->free_inodes--; 662 spin_unlock(&sbinfo->stat_lock); 663 } 664 665 return 1; 666 } 667 668 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo) 669 { 670 if (sbinfo->free_inodes >= 0) { 671 spin_lock(&sbinfo->stat_lock); 672 sbinfo->free_inodes++; 673 spin_unlock(&sbinfo->stat_lock); 674 } 675 } 676 677 678 static struct kmem_cache *hugetlbfs_inode_cachep; 679 680 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb) 681 { 682 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb); 683 struct hugetlbfs_inode_info *p; 684 685 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo))) 686 return NULL; 687 p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL); 688 if (unlikely(!p)) { 689 hugetlbfs_inc_free_inodes(sbinfo); 690 return NULL; 691 } 692 return &p->vfs_inode; 693 } 694 695 static void hugetlbfs_i_callback(struct rcu_head *head) 696 { 697 struct inode *inode = container_of(head, struct inode, i_rcu); 698 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode)); 699 } 700 701 static void hugetlbfs_destroy_inode(struct inode *inode) 702 { 703 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb)); 704 mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy); 705 call_rcu(&inode->i_rcu, hugetlbfs_i_callback); 706 } 707 708 static const struct address_space_operations hugetlbfs_aops = { 709 .write_begin = hugetlbfs_write_begin, 710 .write_end = hugetlbfs_write_end, 711 .set_page_dirty = hugetlbfs_set_page_dirty, 712 .migratepage = hugetlbfs_migrate_page, 713 }; 714 715 716 static void init_once(void *foo) 717 { 718 struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo; 719 720 inode_init_once(&ei->vfs_inode); 721 } 722 723 const struct file_operations hugetlbfs_file_operations = { 724 .read = hugetlbfs_read, 725 .mmap = hugetlbfs_file_mmap, 726 .fsync = noop_fsync, 727 .get_unmapped_area = hugetlb_get_unmapped_area, 728 .llseek = default_llseek, 729 }; 730 731 static const struct inode_operations hugetlbfs_dir_inode_operations = { 732 .create = hugetlbfs_create, 733 .lookup = simple_lookup, 734 .link = simple_link, 735 .unlink = simple_unlink, 736 .symlink = hugetlbfs_symlink, 737 .mkdir = hugetlbfs_mkdir, 738 .rmdir = simple_rmdir, 739 .mknod = hugetlbfs_mknod, 740 .rename = simple_rename, 741 .setattr = hugetlbfs_setattr, 742 }; 743 744 static const struct inode_operations hugetlbfs_inode_operations = { 745 .setattr = hugetlbfs_setattr, 746 }; 747 748 static const struct super_operations hugetlbfs_ops = { 749 .alloc_inode = hugetlbfs_alloc_inode, 750 .destroy_inode = hugetlbfs_destroy_inode, 751 .evict_inode = hugetlbfs_evict_inode, 752 .statfs = hugetlbfs_statfs, 753 .put_super = hugetlbfs_put_super, 754 .show_options = generic_show_options, 755 }; 756 757 static int 758 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig) 759 { 760 char *p, *rest; 761 substring_t args[MAX_OPT_ARGS]; 762 int option; 763 unsigned long long size = 0; 764 enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE; 765 766 if (!options) 767 return 0; 768 769 while ((p = strsep(&options, ",")) != NULL) { 770 int token; 771 if (!*p) 772 continue; 773 774 token = match_token(p, tokens, args); 775 switch (token) { 776 case Opt_uid: 777 if (match_int(&args[0], &option)) 778 goto bad_val; 779 pconfig->uid = make_kuid(current_user_ns(), option); 780 if (!uid_valid(pconfig->uid)) 781 goto bad_val; 782 break; 783 784 case Opt_gid: 785 if (match_int(&args[0], &option)) 786 goto bad_val; 787 pconfig->gid = make_kgid(current_user_ns(), option); 788 if (!gid_valid(pconfig->gid)) 789 goto bad_val; 790 break; 791 792 case Opt_mode: 793 if (match_octal(&args[0], &option)) 794 goto bad_val; 795 pconfig->mode = option & 01777U; 796 break; 797 798 case Opt_size: { 799 /* memparse() will accept a K/M/G without a digit */ 800 if (!isdigit(*args[0].from)) 801 goto bad_val; 802 size = memparse(args[0].from, &rest); 803 setsize = SIZE_STD; 804 if (*rest == '%') 805 setsize = SIZE_PERCENT; 806 break; 807 } 808 809 case Opt_nr_inodes: 810 /* memparse() will accept a K/M/G without a digit */ 811 if (!isdigit(*args[0].from)) 812 goto bad_val; 813 pconfig->nr_inodes = memparse(args[0].from, &rest); 814 break; 815 816 case Opt_pagesize: { 817 unsigned long ps; 818 ps = memparse(args[0].from, &rest); 819 pconfig->hstate = size_to_hstate(ps); 820 if (!pconfig->hstate) { 821 pr_err("Unsupported page size %lu MB\n", 822 ps >> 20); 823 return -EINVAL; 824 } 825 break; 826 } 827 828 default: 829 pr_err("Bad mount option: \"%s\"\n", p); 830 return -EINVAL; 831 break; 832 } 833 } 834 835 /* Do size after hstate is set up */ 836 if (setsize > NO_SIZE) { 837 struct hstate *h = pconfig->hstate; 838 if (setsize == SIZE_PERCENT) { 839 size <<= huge_page_shift(h); 840 size *= h->max_huge_pages; 841 do_div(size, 100); 842 } 843 pconfig->nr_blocks = (size >> huge_page_shift(h)); 844 } 845 846 return 0; 847 848 bad_val: 849 pr_err("Bad value '%s' for mount option '%s'\n", args[0].from, p); 850 return -EINVAL; 851 } 852 853 static int 854 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent) 855 { 856 int ret; 857 struct hugetlbfs_config config; 858 struct hugetlbfs_sb_info *sbinfo; 859 860 save_mount_options(sb, data); 861 862 config.nr_blocks = -1; /* No limit on size by default */ 863 config.nr_inodes = -1; /* No limit on number of inodes by default */ 864 config.uid = current_fsuid(); 865 config.gid = current_fsgid(); 866 config.mode = 0755; 867 config.hstate = &default_hstate; 868 ret = hugetlbfs_parse_options(data, &config); 869 if (ret) 870 return ret; 871 872 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL); 873 if (!sbinfo) 874 return -ENOMEM; 875 sb->s_fs_info = sbinfo; 876 sbinfo->hstate = config.hstate; 877 spin_lock_init(&sbinfo->stat_lock); 878 sbinfo->max_inodes = config.nr_inodes; 879 sbinfo->free_inodes = config.nr_inodes; 880 sbinfo->spool = NULL; 881 if (config.nr_blocks != -1) { 882 sbinfo->spool = hugepage_new_subpool(config.nr_blocks); 883 if (!sbinfo->spool) 884 goto out_free; 885 } 886 sb->s_maxbytes = MAX_LFS_FILESIZE; 887 sb->s_blocksize = huge_page_size(config.hstate); 888 sb->s_blocksize_bits = huge_page_shift(config.hstate); 889 sb->s_magic = HUGETLBFS_MAGIC; 890 sb->s_op = &hugetlbfs_ops; 891 sb->s_time_gran = 1; 892 sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config)); 893 if (!sb->s_root) 894 goto out_free; 895 return 0; 896 out_free: 897 kfree(sbinfo->spool); 898 kfree(sbinfo); 899 return -ENOMEM; 900 } 901 902 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type, 903 int flags, const char *dev_name, void *data) 904 { 905 return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super); 906 } 907 908 static struct file_system_type hugetlbfs_fs_type = { 909 .name = "hugetlbfs", 910 .mount = hugetlbfs_mount, 911 .kill_sb = kill_litter_super, 912 }; 913 MODULE_ALIAS_FS("hugetlbfs"); 914 915 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE]; 916 917 static int can_do_hugetlb_shm(void) 918 { 919 kgid_t shm_group; 920 shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group); 921 return capable(CAP_IPC_LOCK) || in_group_p(shm_group); 922 } 923 924 static int get_hstate_idx(int page_size_log) 925 { 926 struct hstate *h = hstate_sizelog(page_size_log); 927 928 if (!h) 929 return -1; 930 return h - hstates; 931 } 932 933 static const struct dentry_operations anon_ops = { 934 .d_dname = simple_dname 935 }; 936 937 /* 938 * Note that size should be aligned to proper hugepage size in caller side, 939 * otherwise hugetlb_reserve_pages reserves one less hugepages than intended. 940 */ 941 struct file *hugetlb_file_setup(const char *name, size_t size, 942 vm_flags_t acctflag, struct user_struct **user, 943 int creat_flags, int page_size_log) 944 { 945 struct file *file = ERR_PTR(-ENOMEM); 946 struct inode *inode; 947 struct path path; 948 struct super_block *sb; 949 struct qstr quick_string; 950 int hstate_idx; 951 952 hstate_idx = get_hstate_idx(page_size_log); 953 if (hstate_idx < 0) 954 return ERR_PTR(-ENODEV); 955 956 *user = NULL; 957 if (!hugetlbfs_vfsmount[hstate_idx]) 958 return ERR_PTR(-ENOENT); 959 960 if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) { 961 *user = current_user(); 962 if (user_shm_lock(size, *user)) { 963 task_lock(current); 964 pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n", 965 current->comm, current->pid); 966 task_unlock(current); 967 } else { 968 *user = NULL; 969 return ERR_PTR(-EPERM); 970 } 971 } 972 973 sb = hugetlbfs_vfsmount[hstate_idx]->mnt_sb; 974 quick_string.name = name; 975 quick_string.len = strlen(quick_string.name); 976 quick_string.hash = 0; 977 path.dentry = d_alloc_pseudo(sb, &quick_string); 978 if (!path.dentry) 979 goto out_shm_unlock; 980 981 d_set_d_op(path.dentry, &anon_ops); 982 path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]); 983 file = ERR_PTR(-ENOSPC); 984 inode = hugetlbfs_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0); 985 if (!inode) 986 goto out_dentry; 987 988 file = ERR_PTR(-ENOMEM); 989 if (hugetlb_reserve_pages(inode, 0, 990 size >> huge_page_shift(hstate_inode(inode)), NULL, 991 acctflag)) 992 goto out_inode; 993 994 d_instantiate(path.dentry, inode); 995 inode->i_size = size; 996 clear_nlink(inode); 997 998 file = alloc_file(&path, FMODE_WRITE | FMODE_READ, 999 &hugetlbfs_file_operations); 1000 if (IS_ERR(file)) 1001 goto out_dentry; /* inode is already attached */ 1002 1003 return file; 1004 1005 out_inode: 1006 iput(inode); 1007 out_dentry: 1008 path_put(&path); 1009 out_shm_unlock: 1010 if (*user) { 1011 user_shm_unlock(size, *user); 1012 *user = NULL; 1013 } 1014 return file; 1015 } 1016 1017 static int __init init_hugetlbfs_fs(void) 1018 { 1019 struct hstate *h; 1020 int error; 1021 int i; 1022 1023 if (!hugepages_supported()) { 1024 pr_info("disabling because there are no supported hugepage sizes\n"); 1025 return -ENOTSUPP; 1026 } 1027 1028 error = -ENOMEM; 1029 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache", 1030 sizeof(struct hugetlbfs_inode_info), 1031 0, 0, init_once); 1032 if (hugetlbfs_inode_cachep == NULL) 1033 goto out2; 1034 1035 error = register_filesystem(&hugetlbfs_fs_type); 1036 if (error) 1037 goto out; 1038 1039 i = 0; 1040 for_each_hstate(h) { 1041 char buf[50]; 1042 unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10); 1043 1044 snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb); 1045 hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type, 1046 buf); 1047 1048 if (IS_ERR(hugetlbfs_vfsmount[i])) { 1049 pr_err("Cannot mount internal hugetlbfs for " 1050 "page size %uK", ps_kb); 1051 error = PTR_ERR(hugetlbfs_vfsmount[i]); 1052 hugetlbfs_vfsmount[i] = NULL; 1053 } 1054 i++; 1055 } 1056 /* Non default hstates are optional */ 1057 if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx])) 1058 return 0; 1059 1060 out: 1061 kmem_cache_destroy(hugetlbfs_inode_cachep); 1062 out2: 1063 return error; 1064 } 1065 1066 static void __exit exit_hugetlbfs_fs(void) 1067 { 1068 struct hstate *h; 1069 int i; 1070 1071 1072 /* 1073 * Make sure all delayed rcu free inodes are flushed before we 1074 * destroy cache. 1075 */ 1076 rcu_barrier(); 1077 kmem_cache_destroy(hugetlbfs_inode_cachep); 1078 i = 0; 1079 for_each_hstate(h) 1080 kern_unmount(hugetlbfs_vfsmount[i++]); 1081 unregister_filesystem(&hugetlbfs_fs_type); 1082 } 1083 1084 module_init(init_hugetlbfs_fs) 1085 module_exit(exit_hugetlbfs_fs) 1086 1087 MODULE_LICENSE("GPL"); 1088