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/ima.h> 34 35 #include <asm/uaccess.h> 36 37 /* some random number */ 38 #define HUGETLBFS_MAGIC 0x958458f6 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 static struct backing_dev_info hugetlbfs_backing_dev_info = { 47 .name = "hugetlbfs", 48 .ra_pages = 0, /* No readahead */ 49 .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, 50 }; 51 52 int sysctl_hugetlb_shm_group; 53 54 enum { 55 Opt_size, Opt_nr_inodes, 56 Opt_mode, Opt_uid, Opt_gid, 57 Opt_pagesize, 58 Opt_err, 59 }; 60 61 static const match_table_t tokens = { 62 {Opt_size, "size=%s"}, 63 {Opt_nr_inodes, "nr_inodes=%s"}, 64 {Opt_mode, "mode=%o"}, 65 {Opt_uid, "uid=%u"}, 66 {Opt_gid, "gid=%u"}, 67 {Opt_pagesize, "pagesize=%s"}, 68 {Opt_err, NULL}, 69 }; 70 71 static void huge_pagevec_release(struct pagevec *pvec) 72 { 73 int i; 74 75 for (i = 0; i < pagevec_count(pvec); ++i) 76 put_page(pvec->pages[i]); 77 78 pagevec_reinit(pvec); 79 } 80 81 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma) 82 { 83 struct inode *inode = file->f_path.dentry->d_inode; 84 loff_t len, vma_len; 85 int ret; 86 struct hstate *h = hstate_file(file); 87 88 /* 89 * vma address alignment (but not the pgoff alignment) has 90 * already been checked by prepare_hugepage_range. If you add 91 * any error returns here, do so after setting VM_HUGETLB, so 92 * is_vm_hugetlb_page tests below unmap_region go the right 93 * way when do_mmap_pgoff unwinds (may be important on powerpc 94 * and ia64). 95 */ 96 vma->vm_flags |= VM_HUGETLB | VM_RESERVED; 97 vma->vm_ops = &hugetlb_vm_ops; 98 99 if (vma->vm_pgoff & ~(huge_page_mask(h) >> PAGE_SHIFT)) 100 return -EINVAL; 101 102 vma_len = (loff_t)(vma->vm_end - vma->vm_start); 103 104 mutex_lock(&inode->i_mutex); 105 file_accessed(file); 106 107 ret = -ENOMEM; 108 len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); 109 110 if (hugetlb_reserve_pages(inode, 111 vma->vm_pgoff >> huge_page_order(h), 112 len >> huge_page_shift(h), vma, 113 vma->vm_flags)) 114 goto out; 115 116 ret = 0; 117 hugetlb_prefault_arch_hook(vma->vm_mm); 118 if (vma->vm_flags & VM_WRITE && inode->i_size < len) 119 inode->i_size = len; 120 out: 121 mutex_unlock(&inode->i_mutex); 122 123 return ret; 124 } 125 126 /* 127 * Called under down_write(mmap_sem). 128 */ 129 130 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA 131 static unsigned long 132 hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 133 unsigned long len, unsigned long pgoff, unsigned long flags) 134 { 135 struct mm_struct *mm = current->mm; 136 struct vm_area_struct *vma; 137 unsigned long start_addr; 138 struct hstate *h = hstate_file(file); 139 140 if (len & ~huge_page_mask(h)) 141 return -EINVAL; 142 if (len > TASK_SIZE) 143 return -ENOMEM; 144 145 if (flags & MAP_FIXED) { 146 if (prepare_hugepage_range(file, addr, len)) 147 return -EINVAL; 148 return addr; 149 } 150 151 if (addr) { 152 addr = ALIGN(addr, huge_page_size(h)); 153 vma = find_vma(mm, addr); 154 if (TASK_SIZE - len >= addr && 155 (!vma || addr + len <= vma->vm_start)) 156 return addr; 157 } 158 159 start_addr = mm->free_area_cache; 160 161 if (len <= mm->cached_hole_size) 162 start_addr = TASK_UNMAPPED_BASE; 163 164 full_search: 165 addr = ALIGN(start_addr, huge_page_size(h)); 166 167 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { 168 /* At this point: (!vma || addr < vma->vm_end). */ 169 if (TASK_SIZE - len < addr) { 170 /* 171 * Start a new search - just in case we missed 172 * some holes. 173 */ 174 if (start_addr != TASK_UNMAPPED_BASE) { 175 start_addr = TASK_UNMAPPED_BASE; 176 goto full_search; 177 } 178 return -ENOMEM; 179 } 180 181 if (!vma || addr + len <= vma->vm_start) 182 return addr; 183 addr = ALIGN(vma->vm_end, huge_page_size(h)); 184 } 185 } 186 #endif 187 188 static int 189 hugetlbfs_read_actor(struct page *page, unsigned long offset, 190 char __user *buf, unsigned long count, 191 unsigned long size) 192 { 193 char *kaddr; 194 unsigned long left, copied = 0; 195 int i, chunksize; 196 197 if (size > count) 198 size = count; 199 200 /* Find which 4k chunk and offset with in that chunk */ 201 i = offset >> PAGE_CACHE_SHIFT; 202 offset = offset & ~PAGE_CACHE_MASK; 203 204 while (size) { 205 chunksize = PAGE_CACHE_SIZE; 206 if (offset) 207 chunksize -= offset; 208 if (chunksize > size) 209 chunksize = size; 210 kaddr = kmap(&page[i]); 211 left = __copy_to_user(buf, kaddr + offset, chunksize); 212 kunmap(&page[i]); 213 if (left) { 214 copied += (chunksize - left); 215 break; 216 } 217 offset = 0; 218 size -= chunksize; 219 buf += chunksize; 220 copied += chunksize; 221 i++; 222 } 223 return copied ? copied : -EFAULT; 224 } 225 226 /* 227 * Support for read() - Find the page attached to f_mapping and copy out the 228 * data. Its *very* similar to do_generic_mapping_read(), we can't use that 229 * since it has PAGE_CACHE_SIZE assumptions. 230 */ 231 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf, 232 size_t len, loff_t *ppos) 233 { 234 struct hstate *h = hstate_file(filp); 235 struct address_space *mapping = filp->f_mapping; 236 struct inode *inode = mapping->host; 237 unsigned long index = *ppos >> huge_page_shift(h); 238 unsigned long offset = *ppos & ~huge_page_mask(h); 239 unsigned long end_index; 240 loff_t isize; 241 ssize_t retval = 0; 242 243 mutex_lock(&inode->i_mutex); 244 245 /* validate length */ 246 if (len == 0) 247 goto out; 248 249 isize = i_size_read(inode); 250 if (!isize) 251 goto out; 252 253 end_index = (isize - 1) >> huge_page_shift(h); 254 for (;;) { 255 struct page *page; 256 unsigned long nr, ret; 257 int ra; 258 259 /* nr is the maximum number of bytes to copy from this page */ 260 nr = huge_page_size(h); 261 if (index >= end_index) { 262 if (index > end_index) 263 goto out; 264 nr = ((isize - 1) & ~huge_page_mask(h)) + 1; 265 if (nr <= offset) { 266 goto out; 267 } 268 } 269 nr = nr - offset; 270 271 /* Find the page */ 272 page = find_get_page(mapping, index); 273 if (unlikely(page == NULL)) { 274 /* 275 * We have a HOLE, zero out the user-buffer for the 276 * length of the hole or request. 277 */ 278 ret = len < nr ? len : nr; 279 if (clear_user(buf, ret)) 280 ra = -EFAULT; 281 else 282 ra = 0; 283 } else { 284 /* 285 * We have the page, copy it to user space buffer. 286 */ 287 ra = hugetlbfs_read_actor(page, offset, buf, len, nr); 288 ret = ra; 289 } 290 if (ra < 0) { 291 if (retval == 0) 292 retval = ra; 293 if (page) 294 page_cache_release(page); 295 goto out; 296 } 297 298 offset += ret; 299 retval += ret; 300 len -= ret; 301 index += offset >> huge_page_shift(h); 302 offset &= ~huge_page_mask(h); 303 304 if (page) 305 page_cache_release(page); 306 307 /* short read or no more work */ 308 if ((ret != nr) || (len == 0)) 309 break; 310 } 311 out: 312 *ppos = ((loff_t)index << huge_page_shift(h)) + offset; 313 mutex_unlock(&inode->i_mutex); 314 return retval; 315 } 316 317 static int hugetlbfs_write_begin(struct file *file, 318 struct address_space *mapping, 319 loff_t pos, unsigned len, unsigned flags, 320 struct page **pagep, void **fsdata) 321 { 322 return -EINVAL; 323 } 324 325 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping, 326 loff_t pos, unsigned len, unsigned copied, 327 struct page *page, void *fsdata) 328 { 329 BUG(); 330 return -EINVAL; 331 } 332 333 static void truncate_huge_page(struct page *page) 334 { 335 cancel_dirty_page(page, /* No IO accounting for huge pages? */0); 336 ClearPageUptodate(page); 337 remove_from_page_cache(page); 338 put_page(page); 339 } 340 341 static void truncate_hugepages(struct inode *inode, loff_t lstart) 342 { 343 struct hstate *h = hstate_inode(inode); 344 struct address_space *mapping = &inode->i_data; 345 const pgoff_t start = lstart >> huge_page_shift(h); 346 struct pagevec pvec; 347 pgoff_t next; 348 int i, freed = 0; 349 350 pagevec_init(&pvec, 0); 351 next = start; 352 while (1) { 353 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { 354 if (next == start) 355 break; 356 next = start; 357 continue; 358 } 359 360 for (i = 0; i < pagevec_count(&pvec); ++i) { 361 struct page *page = pvec.pages[i]; 362 363 lock_page(page); 364 if (page->index > next) 365 next = page->index; 366 ++next; 367 truncate_huge_page(page); 368 unlock_page(page); 369 freed++; 370 } 371 huge_pagevec_release(&pvec); 372 } 373 BUG_ON(!lstart && mapping->nrpages); 374 hugetlb_unreserve_pages(inode, start, freed); 375 } 376 377 static void hugetlbfs_delete_inode(struct inode *inode) 378 { 379 truncate_hugepages(inode, 0); 380 clear_inode(inode); 381 } 382 383 static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock) 384 { 385 struct super_block *sb = inode->i_sb; 386 387 if (!hlist_unhashed(&inode->i_hash)) { 388 if (!(inode->i_state & (I_DIRTY|I_SYNC))) 389 list_move(&inode->i_list, &inode_unused); 390 inodes_stat.nr_unused++; 391 if (!sb || (sb->s_flags & MS_ACTIVE)) { 392 spin_unlock(&inode_lock); 393 return; 394 } 395 inode->i_state |= I_WILL_FREE; 396 spin_unlock(&inode_lock); 397 /* 398 * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK 399 * in our backing_dev_info. 400 */ 401 write_inode_now(inode, 1); 402 spin_lock(&inode_lock); 403 inode->i_state &= ~I_WILL_FREE; 404 inodes_stat.nr_unused--; 405 hlist_del_init(&inode->i_hash); 406 } 407 list_del_init(&inode->i_list); 408 list_del_init(&inode->i_sb_list); 409 inode->i_state |= I_FREEING; 410 inodes_stat.nr_inodes--; 411 spin_unlock(&inode_lock); 412 truncate_hugepages(inode, 0); 413 clear_inode(inode); 414 destroy_inode(inode); 415 } 416 417 static void hugetlbfs_drop_inode(struct inode *inode) 418 { 419 if (!inode->i_nlink) 420 generic_delete_inode(inode); 421 else 422 hugetlbfs_forget_inode(inode); 423 } 424 425 static inline void 426 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff) 427 { 428 struct vm_area_struct *vma; 429 struct prio_tree_iter iter; 430 431 vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) { 432 unsigned long v_offset; 433 434 /* 435 * Can the expression below overflow on 32-bit arches? 436 * No, because the prio_tree returns us only those vmas 437 * which overlap the truncated area starting at pgoff, 438 * and no vma on a 32-bit arch can span beyond the 4GB. 439 */ 440 if (vma->vm_pgoff < pgoff) 441 v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT; 442 else 443 v_offset = 0; 444 445 __unmap_hugepage_range(vma, 446 vma->vm_start + v_offset, vma->vm_end, NULL); 447 } 448 } 449 450 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset) 451 { 452 pgoff_t pgoff; 453 struct address_space *mapping = inode->i_mapping; 454 struct hstate *h = hstate_inode(inode); 455 456 BUG_ON(offset & ~huge_page_mask(h)); 457 pgoff = offset >> PAGE_SHIFT; 458 459 i_size_write(inode, offset); 460 spin_lock(&mapping->i_mmap_lock); 461 if (!prio_tree_empty(&mapping->i_mmap)) 462 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff); 463 spin_unlock(&mapping->i_mmap_lock); 464 truncate_hugepages(inode, offset); 465 return 0; 466 } 467 468 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr) 469 { 470 struct inode *inode = dentry->d_inode; 471 struct hstate *h = hstate_inode(inode); 472 int error; 473 unsigned int ia_valid = attr->ia_valid; 474 475 BUG_ON(!inode); 476 477 error = inode_change_ok(inode, attr); 478 if (error) 479 goto out; 480 481 if (ia_valid & ATTR_SIZE) { 482 error = -EINVAL; 483 if (!(attr->ia_size & ~huge_page_mask(h))) 484 error = hugetlb_vmtruncate(inode, attr->ia_size); 485 if (error) 486 goto out; 487 attr->ia_valid &= ~ATTR_SIZE; 488 } 489 error = inode_setattr(inode, attr); 490 out: 491 return error; 492 } 493 494 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid, 495 gid_t gid, int mode, dev_t dev) 496 { 497 struct inode *inode; 498 499 inode = new_inode(sb); 500 if (inode) { 501 struct hugetlbfs_inode_info *info; 502 inode->i_mode = mode; 503 inode->i_uid = uid; 504 inode->i_gid = gid; 505 inode->i_mapping->a_ops = &hugetlbfs_aops; 506 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info; 507 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 508 INIT_LIST_HEAD(&inode->i_mapping->private_list); 509 info = HUGETLBFS_I(inode); 510 mpol_shared_policy_init(&info->policy, NULL); 511 switch (mode & S_IFMT) { 512 default: 513 init_special_inode(inode, mode, dev); 514 break; 515 case S_IFREG: 516 inode->i_op = &hugetlbfs_inode_operations; 517 inode->i_fop = &hugetlbfs_file_operations; 518 break; 519 case S_IFDIR: 520 inode->i_op = &hugetlbfs_dir_inode_operations; 521 inode->i_fop = &simple_dir_operations; 522 523 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 524 inc_nlink(inode); 525 break; 526 case S_IFLNK: 527 inode->i_op = &page_symlink_inode_operations; 528 break; 529 } 530 } 531 return inode; 532 } 533 534 /* 535 * File creation. Allocate an inode, and we're done.. 536 */ 537 static int hugetlbfs_mknod(struct inode *dir, 538 struct dentry *dentry, int mode, dev_t dev) 539 { 540 struct inode *inode; 541 int error = -ENOSPC; 542 gid_t gid; 543 544 if (dir->i_mode & S_ISGID) { 545 gid = dir->i_gid; 546 if (S_ISDIR(mode)) 547 mode |= S_ISGID; 548 } else { 549 gid = current_fsgid(); 550 } 551 inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(), gid, mode, dev); 552 if (inode) { 553 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 554 d_instantiate(dentry, inode); 555 dget(dentry); /* Extra count - pin the dentry in core */ 556 error = 0; 557 } 558 return error; 559 } 560 561 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) 562 { 563 int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0); 564 if (!retval) 565 inc_nlink(dir); 566 return retval; 567 } 568 569 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd) 570 { 571 return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0); 572 } 573 574 static int hugetlbfs_symlink(struct inode *dir, 575 struct dentry *dentry, const char *symname) 576 { 577 struct inode *inode; 578 int error = -ENOSPC; 579 gid_t gid; 580 581 if (dir->i_mode & S_ISGID) 582 gid = dir->i_gid; 583 else 584 gid = current_fsgid(); 585 586 inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(), 587 gid, S_IFLNK|S_IRWXUGO, 0); 588 if (inode) { 589 int l = strlen(symname)+1; 590 error = page_symlink(inode, symname, l); 591 if (!error) { 592 d_instantiate(dentry, inode); 593 dget(dentry); 594 } else 595 iput(inode); 596 } 597 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 598 599 return error; 600 } 601 602 /* 603 * mark the head page dirty 604 */ 605 static int hugetlbfs_set_page_dirty(struct page *page) 606 { 607 struct page *head = compound_head(page); 608 609 SetPageDirty(head); 610 return 0; 611 } 612 613 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf) 614 { 615 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb); 616 struct hstate *h = hstate_inode(dentry->d_inode); 617 618 buf->f_type = HUGETLBFS_MAGIC; 619 buf->f_bsize = huge_page_size(h); 620 if (sbinfo) { 621 spin_lock(&sbinfo->stat_lock); 622 /* If no limits set, just report 0 for max/free/used 623 * blocks, like simple_statfs() */ 624 if (sbinfo->max_blocks >= 0) { 625 buf->f_blocks = sbinfo->max_blocks; 626 buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; 627 buf->f_files = sbinfo->max_inodes; 628 buf->f_ffree = sbinfo->free_inodes; 629 } 630 spin_unlock(&sbinfo->stat_lock); 631 } 632 buf->f_namelen = NAME_MAX; 633 return 0; 634 } 635 636 static void hugetlbfs_put_super(struct super_block *sb) 637 { 638 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb); 639 640 if (sbi) { 641 sb->s_fs_info = NULL; 642 kfree(sbi); 643 } 644 } 645 646 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo) 647 { 648 if (sbinfo->free_inodes >= 0) { 649 spin_lock(&sbinfo->stat_lock); 650 if (unlikely(!sbinfo->free_inodes)) { 651 spin_unlock(&sbinfo->stat_lock); 652 return 0; 653 } 654 sbinfo->free_inodes--; 655 spin_unlock(&sbinfo->stat_lock); 656 } 657 658 return 1; 659 } 660 661 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo) 662 { 663 if (sbinfo->free_inodes >= 0) { 664 spin_lock(&sbinfo->stat_lock); 665 sbinfo->free_inodes++; 666 spin_unlock(&sbinfo->stat_lock); 667 } 668 } 669 670 671 static struct kmem_cache *hugetlbfs_inode_cachep; 672 673 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb) 674 { 675 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb); 676 struct hugetlbfs_inode_info *p; 677 678 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo))) 679 return NULL; 680 p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL); 681 if (unlikely(!p)) { 682 hugetlbfs_inc_free_inodes(sbinfo); 683 return NULL; 684 } 685 return &p->vfs_inode; 686 } 687 688 static void hugetlbfs_destroy_inode(struct inode *inode) 689 { 690 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb)); 691 mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy); 692 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode)); 693 } 694 695 static const struct address_space_operations hugetlbfs_aops = { 696 .write_begin = hugetlbfs_write_begin, 697 .write_end = hugetlbfs_write_end, 698 .set_page_dirty = hugetlbfs_set_page_dirty, 699 }; 700 701 702 static void init_once(void *foo) 703 { 704 struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo; 705 706 inode_init_once(&ei->vfs_inode); 707 } 708 709 const struct file_operations hugetlbfs_file_operations = { 710 .read = hugetlbfs_read, 711 .mmap = hugetlbfs_file_mmap, 712 .fsync = simple_sync_file, 713 .get_unmapped_area = hugetlb_get_unmapped_area, 714 }; 715 716 static const struct inode_operations hugetlbfs_dir_inode_operations = { 717 .create = hugetlbfs_create, 718 .lookup = simple_lookup, 719 .link = simple_link, 720 .unlink = simple_unlink, 721 .symlink = hugetlbfs_symlink, 722 .mkdir = hugetlbfs_mkdir, 723 .rmdir = simple_rmdir, 724 .mknod = hugetlbfs_mknod, 725 .rename = simple_rename, 726 .setattr = hugetlbfs_setattr, 727 }; 728 729 static const struct inode_operations hugetlbfs_inode_operations = { 730 .setattr = hugetlbfs_setattr, 731 }; 732 733 static const struct super_operations hugetlbfs_ops = { 734 .alloc_inode = hugetlbfs_alloc_inode, 735 .destroy_inode = hugetlbfs_destroy_inode, 736 .statfs = hugetlbfs_statfs, 737 .delete_inode = hugetlbfs_delete_inode, 738 .drop_inode = hugetlbfs_drop_inode, 739 .put_super = hugetlbfs_put_super, 740 .show_options = generic_show_options, 741 }; 742 743 static int 744 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig) 745 { 746 char *p, *rest; 747 substring_t args[MAX_OPT_ARGS]; 748 int option; 749 unsigned long long size = 0; 750 enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE; 751 752 if (!options) 753 return 0; 754 755 while ((p = strsep(&options, ",")) != NULL) { 756 int token; 757 if (!*p) 758 continue; 759 760 token = match_token(p, tokens, args); 761 switch (token) { 762 case Opt_uid: 763 if (match_int(&args[0], &option)) 764 goto bad_val; 765 pconfig->uid = option; 766 break; 767 768 case Opt_gid: 769 if (match_int(&args[0], &option)) 770 goto bad_val; 771 pconfig->gid = option; 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 struct inode * inode; 842 struct dentry * root; 843 int ret; 844 struct hugetlbfs_config config; 845 struct hugetlbfs_sb_info *sbinfo; 846 847 save_mount_options(sb, data); 848 849 config.nr_blocks = -1; /* No limit on size by default */ 850 config.nr_inodes = -1; /* No limit on number of inodes by default */ 851 config.uid = current_fsuid(); 852 config.gid = current_fsgid(); 853 config.mode = 0755; 854 config.hstate = &default_hstate; 855 ret = hugetlbfs_parse_options(data, &config); 856 if (ret) 857 return ret; 858 859 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL); 860 if (!sbinfo) 861 return -ENOMEM; 862 sb->s_fs_info = sbinfo; 863 sbinfo->hstate = config.hstate; 864 spin_lock_init(&sbinfo->stat_lock); 865 sbinfo->max_blocks = config.nr_blocks; 866 sbinfo->free_blocks = config.nr_blocks; 867 sbinfo->max_inodes = config.nr_inodes; 868 sbinfo->free_inodes = config.nr_inodes; 869 sb->s_maxbytes = MAX_LFS_FILESIZE; 870 sb->s_blocksize = huge_page_size(config.hstate); 871 sb->s_blocksize_bits = huge_page_shift(config.hstate); 872 sb->s_magic = HUGETLBFS_MAGIC; 873 sb->s_op = &hugetlbfs_ops; 874 sb->s_time_gran = 1; 875 inode = hugetlbfs_get_inode(sb, config.uid, config.gid, 876 S_IFDIR | config.mode, 0); 877 if (!inode) 878 goto out_free; 879 880 root = d_alloc_root(inode); 881 if (!root) { 882 iput(inode); 883 goto out_free; 884 } 885 sb->s_root = root; 886 return 0; 887 out_free: 888 kfree(sbinfo); 889 return -ENOMEM; 890 } 891 892 int hugetlb_get_quota(struct address_space *mapping, long delta) 893 { 894 int ret = 0; 895 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb); 896 897 if (sbinfo->free_blocks > -1) { 898 spin_lock(&sbinfo->stat_lock); 899 if (sbinfo->free_blocks - delta >= 0) 900 sbinfo->free_blocks -= delta; 901 else 902 ret = -ENOMEM; 903 spin_unlock(&sbinfo->stat_lock); 904 } 905 906 return ret; 907 } 908 909 void hugetlb_put_quota(struct address_space *mapping, long delta) 910 { 911 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb); 912 913 if (sbinfo->free_blocks > -1) { 914 spin_lock(&sbinfo->stat_lock); 915 sbinfo->free_blocks += delta; 916 spin_unlock(&sbinfo->stat_lock); 917 } 918 } 919 920 static int hugetlbfs_get_sb(struct file_system_type *fs_type, 921 int flags, const char *dev_name, void *data, struct vfsmount *mnt) 922 { 923 return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super, mnt); 924 } 925 926 static struct file_system_type hugetlbfs_fs_type = { 927 .name = "hugetlbfs", 928 .get_sb = hugetlbfs_get_sb, 929 .kill_sb = kill_litter_super, 930 }; 931 932 static struct vfsmount *hugetlbfs_vfsmount; 933 934 static int can_do_hugetlb_shm(void) 935 { 936 return capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group); 937 } 938 939 struct file *hugetlb_file_setup(const char *name, size_t size, int acctflag, 940 struct user_struct **user) 941 { 942 int error = -ENOMEM; 943 struct file *file; 944 struct inode *inode; 945 struct dentry *dentry, *root; 946 struct qstr quick_string; 947 948 *user = NULL; 949 if (!hugetlbfs_vfsmount) 950 return ERR_PTR(-ENOENT); 951 952 if (!can_do_hugetlb_shm()) { 953 *user = current_user(); 954 if (user_shm_lock(size, *user)) { 955 WARN_ONCE(1, 956 "Using mlock ulimits for SHM_HUGETLB deprecated\n"); 957 } else { 958 *user = NULL; 959 return ERR_PTR(-EPERM); 960 } 961 } 962 963 root = hugetlbfs_vfsmount->mnt_root; 964 quick_string.name = name; 965 quick_string.len = strlen(quick_string.name); 966 quick_string.hash = 0; 967 dentry = d_alloc(root, &quick_string); 968 if (!dentry) 969 goto out_shm_unlock; 970 971 error = -ENOSPC; 972 inode = hugetlbfs_get_inode(root->d_sb, current_fsuid(), 973 current_fsgid(), S_IFREG | S_IRWXUGO, 0); 974 if (!inode) 975 goto out_dentry; 976 977 error = -ENOMEM; 978 if (hugetlb_reserve_pages(inode, 0, 979 size >> huge_page_shift(hstate_inode(inode)), NULL, 980 acctflag)) 981 goto out_inode; 982 983 d_instantiate(dentry, inode); 984 inode->i_size = size; 985 inode->i_nlink = 0; 986 987 error = -ENFILE; 988 file = alloc_file(hugetlbfs_vfsmount, dentry, 989 FMODE_WRITE | FMODE_READ, 990 &hugetlbfs_file_operations); 991 if (!file) 992 goto out_dentry; /* inode is already attached */ 993 ima_counts_get(file); 994 995 return file; 996 997 out_inode: 998 iput(inode); 999 out_dentry: 1000 dput(dentry); 1001 out_shm_unlock: 1002 if (*user) { 1003 user_shm_unlock(size, *user); 1004 *user = NULL; 1005 } 1006 return ERR_PTR(error); 1007 } 1008 1009 static int __init init_hugetlbfs_fs(void) 1010 { 1011 int error; 1012 struct vfsmount *vfsmount; 1013 1014 error = bdi_init(&hugetlbfs_backing_dev_info); 1015 if (error) 1016 return error; 1017 1018 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache", 1019 sizeof(struct hugetlbfs_inode_info), 1020 0, 0, init_once); 1021 if (hugetlbfs_inode_cachep == NULL) 1022 goto out2; 1023 1024 error = register_filesystem(&hugetlbfs_fs_type); 1025 if (error) 1026 goto out; 1027 1028 vfsmount = kern_mount(&hugetlbfs_fs_type); 1029 1030 if (!IS_ERR(vfsmount)) { 1031 hugetlbfs_vfsmount = vfsmount; 1032 return 0; 1033 } 1034 1035 error = PTR_ERR(vfsmount); 1036 1037 out: 1038 if (error) 1039 kmem_cache_destroy(hugetlbfs_inode_cachep); 1040 out2: 1041 bdi_destroy(&hugetlbfs_backing_dev_info); 1042 return error; 1043 } 1044 1045 static void __exit exit_hugetlbfs_fs(void) 1046 { 1047 kmem_cache_destroy(hugetlbfs_inode_cachep); 1048 unregister_filesystem(&hugetlbfs_fs_type); 1049 bdi_destroy(&hugetlbfs_backing_dev_info); 1050 } 1051 1052 module_init(init_hugetlbfs_fs) 1053 module_exit(exit_hugetlbfs_fs) 1054 1055 MODULE_LICENSE("GPL"); 1056