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