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