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/writeback.h> 17 #include <linux/pagemap.h> 18 #include <linux/highmem.h> 19 #include <linux/init.h> 20 #include <linux/string.h> 21 #include <linux/capability.h> 22 #include <linux/backing-dev.h> 23 #include <linux/hugetlb.h> 24 #include <linux/pagevec.h> 25 #include <linux/quotaops.h> 26 #include <linux/slab.h> 27 #include <linux/dnotify.h> 28 #include <linux/statfs.h> 29 #include <linux/security.h> 30 31 #include <asm/uaccess.h> 32 33 /* some random number */ 34 #define HUGETLBFS_MAGIC 0x958458f6 35 36 static struct super_operations hugetlbfs_ops; 37 static const struct address_space_operations hugetlbfs_aops; 38 const struct file_operations hugetlbfs_file_operations; 39 static struct inode_operations hugetlbfs_dir_inode_operations; 40 static struct inode_operations hugetlbfs_inode_operations; 41 42 static struct backing_dev_info hugetlbfs_backing_dev_info = { 43 .ra_pages = 0, /* No readahead */ 44 .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, 45 }; 46 47 int sysctl_hugetlb_shm_group; 48 49 static void huge_pagevec_release(struct pagevec *pvec) 50 { 51 int i; 52 53 for (i = 0; i < pagevec_count(pvec); ++i) 54 put_page(pvec->pages[i]); 55 56 pagevec_reinit(pvec); 57 } 58 59 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma) 60 { 61 struct inode *inode = file->f_dentry->d_inode; 62 loff_t len, vma_len; 63 int ret; 64 65 if (vma->vm_pgoff & (HPAGE_SIZE / PAGE_SIZE - 1)) 66 return -EINVAL; 67 68 if (vma->vm_start & ~HPAGE_MASK) 69 return -EINVAL; 70 71 if (vma->vm_end & ~HPAGE_MASK) 72 return -EINVAL; 73 74 if (vma->vm_end - vma->vm_start < HPAGE_SIZE) 75 return -EINVAL; 76 77 vma_len = (loff_t)(vma->vm_end - vma->vm_start); 78 79 mutex_lock(&inode->i_mutex); 80 file_accessed(file); 81 vma->vm_flags |= VM_HUGETLB | VM_RESERVED; 82 vma->vm_ops = &hugetlb_vm_ops; 83 84 ret = -ENOMEM; 85 len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); 86 if (!(vma->vm_flags & VM_WRITE) && len > inode->i_size) 87 goto out; 88 89 if (vma->vm_flags & VM_MAYSHARE && 90 hugetlb_reserve_pages(inode, vma->vm_pgoff >> (HPAGE_SHIFT-PAGE_SHIFT), 91 len >> HPAGE_SHIFT)) 92 goto out; 93 94 ret = 0; 95 hugetlb_prefault_arch_hook(vma->vm_mm); 96 if (inode->i_size < len) 97 inode->i_size = len; 98 out: 99 mutex_unlock(&inode->i_mutex); 100 101 return ret; 102 } 103 104 /* 105 * Called under down_write(mmap_sem). 106 */ 107 108 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA 109 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 110 unsigned long len, unsigned long pgoff, unsigned long flags); 111 #else 112 static unsigned long 113 hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 114 unsigned long len, unsigned long pgoff, unsigned long flags) 115 { 116 struct mm_struct *mm = current->mm; 117 struct vm_area_struct *vma; 118 unsigned long start_addr; 119 120 if (len & ~HPAGE_MASK) 121 return -EINVAL; 122 if (len > TASK_SIZE) 123 return -ENOMEM; 124 125 if (addr) { 126 addr = ALIGN(addr, HPAGE_SIZE); 127 vma = find_vma(mm, addr); 128 if (TASK_SIZE - len >= addr && 129 (!vma || addr + len <= vma->vm_start)) 130 return addr; 131 } 132 133 start_addr = mm->free_area_cache; 134 135 if (len <= mm->cached_hole_size) 136 start_addr = TASK_UNMAPPED_BASE; 137 138 full_search: 139 addr = ALIGN(start_addr, HPAGE_SIZE); 140 141 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { 142 /* At this point: (!vma || addr < vma->vm_end). */ 143 if (TASK_SIZE - len < addr) { 144 /* 145 * Start a new search - just in case we missed 146 * some holes. 147 */ 148 if (start_addr != TASK_UNMAPPED_BASE) { 149 start_addr = TASK_UNMAPPED_BASE; 150 goto full_search; 151 } 152 return -ENOMEM; 153 } 154 155 if (!vma || addr + len <= vma->vm_start) 156 return addr; 157 addr = ALIGN(vma->vm_end, HPAGE_SIZE); 158 } 159 } 160 #endif 161 162 /* 163 * Read a page. Again trivial. If it didn't already exist 164 * in the page cache, it is zero-filled. 165 */ 166 static int hugetlbfs_readpage(struct file *file, struct page * page) 167 { 168 unlock_page(page); 169 return -EINVAL; 170 } 171 172 static int hugetlbfs_prepare_write(struct file *file, 173 struct page *page, unsigned offset, unsigned to) 174 { 175 return -EINVAL; 176 } 177 178 static int hugetlbfs_commit_write(struct file *file, 179 struct page *page, unsigned offset, unsigned to) 180 { 181 return -EINVAL; 182 } 183 184 static void truncate_huge_page(struct page *page) 185 { 186 clear_page_dirty(page); 187 ClearPageUptodate(page); 188 remove_from_page_cache(page); 189 put_page(page); 190 } 191 192 static void truncate_hugepages(struct inode *inode, loff_t lstart) 193 { 194 struct address_space *mapping = &inode->i_data; 195 const pgoff_t start = lstart >> HPAGE_SHIFT; 196 struct pagevec pvec; 197 pgoff_t next; 198 int i, freed = 0; 199 200 pagevec_init(&pvec, 0); 201 next = start; 202 while (1) { 203 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { 204 if (next == start) 205 break; 206 next = start; 207 continue; 208 } 209 210 for (i = 0; i < pagevec_count(&pvec); ++i) { 211 struct page *page = pvec.pages[i]; 212 213 lock_page(page); 214 if (page->index > next) 215 next = page->index; 216 ++next; 217 truncate_huge_page(page); 218 unlock_page(page); 219 hugetlb_put_quota(mapping); 220 freed++; 221 } 222 huge_pagevec_release(&pvec); 223 } 224 BUG_ON(!lstart && mapping->nrpages); 225 hugetlb_unreserve_pages(inode, start, freed); 226 } 227 228 static void hugetlbfs_delete_inode(struct inode *inode) 229 { 230 truncate_hugepages(inode, 0); 231 clear_inode(inode); 232 } 233 234 static void hugetlbfs_forget_inode(struct inode *inode) 235 { 236 struct super_block *sb = inode->i_sb; 237 238 if (!hlist_unhashed(&inode->i_hash)) { 239 if (!(inode->i_state & (I_DIRTY|I_LOCK))) 240 list_move(&inode->i_list, &inode_unused); 241 inodes_stat.nr_unused++; 242 if (!sb || (sb->s_flags & MS_ACTIVE)) { 243 spin_unlock(&inode_lock); 244 return; 245 } 246 inode->i_state |= I_WILL_FREE; 247 spin_unlock(&inode_lock); 248 /* 249 * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK 250 * in our backing_dev_info. 251 */ 252 write_inode_now(inode, 1); 253 spin_lock(&inode_lock); 254 inode->i_state &= ~I_WILL_FREE; 255 inodes_stat.nr_unused--; 256 hlist_del_init(&inode->i_hash); 257 } 258 list_del_init(&inode->i_list); 259 list_del_init(&inode->i_sb_list); 260 inode->i_state |= I_FREEING; 261 inodes_stat.nr_inodes--; 262 spin_unlock(&inode_lock); 263 truncate_hugepages(inode, 0); 264 clear_inode(inode); 265 destroy_inode(inode); 266 } 267 268 static void hugetlbfs_drop_inode(struct inode *inode) 269 { 270 if (!inode->i_nlink) 271 generic_delete_inode(inode); 272 else 273 hugetlbfs_forget_inode(inode); 274 } 275 276 /* 277 * h_pgoff is in HPAGE_SIZE units. 278 * vma->vm_pgoff is in PAGE_SIZE units. 279 */ 280 static inline void 281 hugetlb_vmtruncate_list(struct prio_tree_root *root, unsigned long h_pgoff) 282 { 283 struct vm_area_struct *vma; 284 struct prio_tree_iter iter; 285 286 vma_prio_tree_foreach(vma, &iter, root, h_pgoff, ULONG_MAX) { 287 unsigned long h_vm_pgoff; 288 unsigned long v_offset; 289 290 h_vm_pgoff = vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT); 291 v_offset = (h_pgoff - h_vm_pgoff) << HPAGE_SHIFT; 292 /* 293 * Is this VMA fully outside the truncation point? 294 */ 295 if (h_vm_pgoff >= h_pgoff) 296 v_offset = 0; 297 298 unmap_hugepage_range(vma, 299 vma->vm_start + v_offset, vma->vm_end); 300 } 301 } 302 303 /* 304 * Expanding truncates are not allowed. 305 */ 306 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset) 307 { 308 unsigned long pgoff; 309 struct address_space *mapping = inode->i_mapping; 310 311 if (offset > inode->i_size) 312 return -EINVAL; 313 314 BUG_ON(offset & ~HPAGE_MASK); 315 pgoff = offset >> HPAGE_SHIFT; 316 317 inode->i_size = offset; 318 spin_lock(&mapping->i_mmap_lock); 319 if (!prio_tree_empty(&mapping->i_mmap)) 320 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff); 321 spin_unlock(&mapping->i_mmap_lock); 322 truncate_hugepages(inode, offset); 323 return 0; 324 } 325 326 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr) 327 { 328 struct inode *inode = dentry->d_inode; 329 int error; 330 unsigned int ia_valid = attr->ia_valid; 331 332 BUG_ON(!inode); 333 334 error = inode_change_ok(inode, attr); 335 if (error) 336 goto out; 337 338 if (ia_valid & ATTR_SIZE) { 339 error = -EINVAL; 340 if (!(attr->ia_size & ~HPAGE_MASK)) 341 error = hugetlb_vmtruncate(inode, attr->ia_size); 342 if (error) 343 goto out; 344 attr->ia_valid &= ~ATTR_SIZE; 345 } 346 error = inode_setattr(inode, attr); 347 out: 348 return error; 349 } 350 351 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid, 352 gid_t gid, int mode, dev_t dev) 353 { 354 struct inode *inode; 355 356 inode = new_inode(sb); 357 if (inode) { 358 struct hugetlbfs_inode_info *info; 359 inode->i_mode = mode; 360 inode->i_uid = uid; 361 inode->i_gid = gid; 362 inode->i_blksize = HPAGE_SIZE; 363 inode->i_blocks = 0; 364 inode->i_mapping->a_ops = &hugetlbfs_aops; 365 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info; 366 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 367 INIT_LIST_HEAD(&inode->i_mapping->private_list); 368 info = HUGETLBFS_I(inode); 369 mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, NULL); 370 switch (mode & S_IFMT) { 371 default: 372 init_special_inode(inode, mode, dev); 373 break; 374 case S_IFREG: 375 inode->i_op = &hugetlbfs_inode_operations; 376 inode->i_fop = &hugetlbfs_file_operations; 377 break; 378 case S_IFDIR: 379 inode->i_op = &hugetlbfs_dir_inode_operations; 380 inode->i_fop = &simple_dir_operations; 381 382 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 383 inode->i_nlink++; 384 break; 385 case S_IFLNK: 386 inode->i_op = &page_symlink_inode_operations; 387 break; 388 } 389 } 390 return inode; 391 } 392 393 /* 394 * File creation. Allocate an inode, and we're done.. 395 */ 396 static int hugetlbfs_mknod(struct inode *dir, 397 struct dentry *dentry, int mode, dev_t dev) 398 { 399 struct inode *inode; 400 int error = -ENOSPC; 401 gid_t gid; 402 403 if (dir->i_mode & S_ISGID) { 404 gid = dir->i_gid; 405 if (S_ISDIR(mode)) 406 mode |= S_ISGID; 407 } else { 408 gid = current->fsgid; 409 } 410 inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev); 411 if (inode) { 412 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 413 d_instantiate(dentry, inode); 414 dget(dentry); /* Extra count - pin the dentry in core */ 415 error = 0; 416 } 417 return error; 418 } 419 420 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) 421 { 422 int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0); 423 if (!retval) 424 dir->i_nlink++; 425 return retval; 426 } 427 428 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd) 429 { 430 return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0); 431 } 432 433 static int hugetlbfs_symlink(struct inode *dir, 434 struct dentry *dentry, const char *symname) 435 { 436 struct inode *inode; 437 int error = -ENOSPC; 438 gid_t gid; 439 440 if (dir->i_mode & S_ISGID) 441 gid = dir->i_gid; 442 else 443 gid = current->fsgid; 444 445 inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, 446 gid, S_IFLNK|S_IRWXUGO, 0); 447 if (inode) { 448 int l = strlen(symname)+1; 449 error = page_symlink(inode, symname, l); 450 if (!error) { 451 d_instantiate(dentry, inode); 452 dget(dentry); 453 } else 454 iput(inode); 455 } 456 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 457 458 return error; 459 } 460 461 /* 462 * For direct-IO reads into hugetlb pages 463 */ 464 static int hugetlbfs_set_page_dirty(struct page *page) 465 { 466 return 0; 467 } 468 469 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf) 470 { 471 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb); 472 473 buf->f_type = HUGETLBFS_MAGIC; 474 buf->f_bsize = HPAGE_SIZE; 475 if (sbinfo) { 476 spin_lock(&sbinfo->stat_lock); 477 /* If no limits set, just report 0 for max/free/used 478 * blocks, like simple_statfs() */ 479 if (sbinfo->max_blocks >= 0) { 480 buf->f_blocks = sbinfo->max_blocks; 481 buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; 482 buf->f_files = sbinfo->max_inodes; 483 buf->f_ffree = sbinfo->free_inodes; 484 } 485 spin_unlock(&sbinfo->stat_lock); 486 } 487 buf->f_namelen = NAME_MAX; 488 return 0; 489 } 490 491 static void hugetlbfs_put_super(struct super_block *sb) 492 { 493 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb); 494 495 if (sbi) { 496 sb->s_fs_info = NULL; 497 kfree(sbi); 498 } 499 } 500 501 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo) 502 { 503 if (sbinfo->free_inodes >= 0) { 504 spin_lock(&sbinfo->stat_lock); 505 if (unlikely(!sbinfo->free_inodes)) { 506 spin_unlock(&sbinfo->stat_lock); 507 return 0; 508 } 509 sbinfo->free_inodes--; 510 spin_unlock(&sbinfo->stat_lock); 511 } 512 513 return 1; 514 } 515 516 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo) 517 { 518 if (sbinfo->free_inodes >= 0) { 519 spin_lock(&sbinfo->stat_lock); 520 sbinfo->free_inodes++; 521 spin_unlock(&sbinfo->stat_lock); 522 } 523 } 524 525 526 static kmem_cache_t *hugetlbfs_inode_cachep; 527 528 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb) 529 { 530 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb); 531 struct hugetlbfs_inode_info *p; 532 533 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo))) 534 return NULL; 535 p = kmem_cache_alloc(hugetlbfs_inode_cachep, SLAB_KERNEL); 536 if (unlikely(!p)) { 537 hugetlbfs_inc_free_inodes(sbinfo); 538 return NULL; 539 } 540 return &p->vfs_inode; 541 } 542 543 static void hugetlbfs_destroy_inode(struct inode *inode) 544 { 545 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb)); 546 mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy); 547 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode)); 548 } 549 550 static const struct address_space_operations hugetlbfs_aops = { 551 .readpage = hugetlbfs_readpage, 552 .prepare_write = hugetlbfs_prepare_write, 553 .commit_write = hugetlbfs_commit_write, 554 .set_page_dirty = hugetlbfs_set_page_dirty, 555 }; 556 557 558 static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags) 559 { 560 struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo; 561 562 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == 563 SLAB_CTOR_CONSTRUCTOR) 564 inode_init_once(&ei->vfs_inode); 565 } 566 567 const struct file_operations hugetlbfs_file_operations = { 568 .mmap = hugetlbfs_file_mmap, 569 .fsync = simple_sync_file, 570 .get_unmapped_area = hugetlb_get_unmapped_area, 571 }; 572 573 static struct inode_operations hugetlbfs_dir_inode_operations = { 574 .create = hugetlbfs_create, 575 .lookup = simple_lookup, 576 .link = simple_link, 577 .unlink = simple_unlink, 578 .symlink = hugetlbfs_symlink, 579 .mkdir = hugetlbfs_mkdir, 580 .rmdir = simple_rmdir, 581 .mknod = hugetlbfs_mknod, 582 .rename = simple_rename, 583 .setattr = hugetlbfs_setattr, 584 }; 585 586 static struct inode_operations hugetlbfs_inode_operations = { 587 .setattr = hugetlbfs_setattr, 588 }; 589 590 static struct super_operations hugetlbfs_ops = { 591 .alloc_inode = hugetlbfs_alloc_inode, 592 .destroy_inode = hugetlbfs_destroy_inode, 593 .statfs = hugetlbfs_statfs, 594 .delete_inode = hugetlbfs_delete_inode, 595 .drop_inode = hugetlbfs_drop_inode, 596 .put_super = hugetlbfs_put_super, 597 }; 598 599 static int 600 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig) 601 { 602 char *opt, *value, *rest; 603 604 if (!options) 605 return 0; 606 while ((opt = strsep(&options, ",")) != NULL) { 607 if (!*opt) 608 continue; 609 610 value = strchr(opt, '='); 611 if (!value || !*value) 612 return -EINVAL; 613 else 614 *value++ = '\0'; 615 616 if (!strcmp(opt, "uid")) 617 pconfig->uid = simple_strtoul(value, &value, 0); 618 else if (!strcmp(opt, "gid")) 619 pconfig->gid = simple_strtoul(value, &value, 0); 620 else if (!strcmp(opt, "mode")) 621 pconfig->mode = simple_strtoul(value,&value,0) & 0777U; 622 else if (!strcmp(opt, "size")) { 623 unsigned long long size = memparse(value, &rest); 624 if (*rest == '%') { 625 size <<= HPAGE_SHIFT; 626 size *= max_huge_pages; 627 do_div(size, 100); 628 rest++; 629 } 630 size &= HPAGE_MASK; 631 pconfig->nr_blocks = (size >> HPAGE_SHIFT); 632 value = rest; 633 } else if (!strcmp(opt,"nr_inodes")) { 634 pconfig->nr_inodes = memparse(value, &rest); 635 value = rest; 636 } else 637 return -EINVAL; 638 639 if (*value) 640 return -EINVAL; 641 } 642 return 0; 643 } 644 645 static int 646 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent) 647 { 648 struct inode * inode; 649 struct dentry * root; 650 int ret; 651 struct hugetlbfs_config config; 652 struct hugetlbfs_sb_info *sbinfo; 653 654 config.nr_blocks = -1; /* No limit on size by default */ 655 config.nr_inodes = -1; /* No limit on number of inodes by default */ 656 config.uid = current->fsuid; 657 config.gid = current->fsgid; 658 config.mode = 0755; 659 ret = hugetlbfs_parse_options(data, &config); 660 661 if (ret) 662 return ret; 663 664 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL); 665 if (!sbinfo) 666 return -ENOMEM; 667 sb->s_fs_info = sbinfo; 668 spin_lock_init(&sbinfo->stat_lock); 669 sbinfo->max_blocks = config.nr_blocks; 670 sbinfo->free_blocks = config.nr_blocks; 671 sbinfo->max_inodes = config.nr_inodes; 672 sbinfo->free_inodes = config.nr_inodes; 673 sb->s_maxbytes = MAX_LFS_FILESIZE; 674 sb->s_blocksize = HPAGE_SIZE; 675 sb->s_blocksize_bits = HPAGE_SHIFT; 676 sb->s_magic = HUGETLBFS_MAGIC; 677 sb->s_op = &hugetlbfs_ops; 678 sb->s_time_gran = 1; 679 inode = hugetlbfs_get_inode(sb, config.uid, config.gid, 680 S_IFDIR | config.mode, 0); 681 if (!inode) 682 goto out_free; 683 684 root = d_alloc_root(inode); 685 if (!root) { 686 iput(inode); 687 goto out_free; 688 } 689 sb->s_root = root; 690 return 0; 691 out_free: 692 kfree(sbinfo); 693 return -ENOMEM; 694 } 695 696 int hugetlb_get_quota(struct address_space *mapping) 697 { 698 int ret = 0; 699 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb); 700 701 if (sbinfo->free_blocks > -1) { 702 spin_lock(&sbinfo->stat_lock); 703 if (sbinfo->free_blocks > 0) 704 sbinfo->free_blocks--; 705 else 706 ret = -ENOMEM; 707 spin_unlock(&sbinfo->stat_lock); 708 } 709 710 return ret; 711 } 712 713 void hugetlb_put_quota(struct address_space *mapping) 714 { 715 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb); 716 717 if (sbinfo->free_blocks > -1) { 718 spin_lock(&sbinfo->stat_lock); 719 sbinfo->free_blocks++; 720 spin_unlock(&sbinfo->stat_lock); 721 } 722 } 723 724 static int hugetlbfs_get_sb(struct file_system_type *fs_type, 725 int flags, const char *dev_name, void *data, struct vfsmount *mnt) 726 { 727 return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super, mnt); 728 } 729 730 static struct file_system_type hugetlbfs_fs_type = { 731 .name = "hugetlbfs", 732 .get_sb = hugetlbfs_get_sb, 733 .kill_sb = kill_litter_super, 734 }; 735 736 static struct vfsmount *hugetlbfs_vfsmount; 737 738 static int can_do_hugetlb_shm(void) 739 { 740 return likely(capable(CAP_IPC_LOCK) || 741 in_group_p(sysctl_hugetlb_shm_group) || 742 can_do_mlock()); 743 } 744 745 struct file *hugetlb_zero_setup(size_t size) 746 { 747 int error = -ENOMEM; 748 struct file *file; 749 struct inode *inode; 750 struct dentry *dentry, *root; 751 struct qstr quick_string; 752 char buf[16]; 753 static atomic_t counter; 754 755 if (!can_do_hugetlb_shm()) 756 return ERR_PTR(-EPERM); 757 758 if (!user_shm_lock(size, current->user)) 759 return ERR_PTR(-ENOMEM); 760 761 root = hugetlbfs_vfsmount->mnt_root; 762 snprintf(buf, 16, "%u", atomic_inc_return(&counter)); 763 quick_string.name = buf; 764 quick_string.len = strlen(quick_string.name); 765 quick_string.hash = 0; 766 dentry = d_alloc(root, &quick_string); 767 if (!dentry) 768 goto out_shm_unlock; 769 770 error = -ENFILE; 771 file = get_empty_filp(); 772 if (!file) 773 goto out_dentry; 774 775 error = -ENOSPC; 776 inode = hugetlbfs_get_inode(root->d_sb, current->fsuid, 777 current->fsgid, S_IFREG | S_IRWXUGO, 0); 778 if (!inode) 779 goto out_file; 780 781 error = -ENOMEM; 782 if (hugetlb_reserve_pages(inode, 0, size >> HPAGE_SHIFT)) 783 goto out_inode; 784 785 d_instantiate(dentry, inode); 786 inode->i_size = size; 787 inode->i_nlink = 0; 788 file->f_vfsmnt = mntget(hugetlbfs_vfsmount); 789 file->f_dentry = dentry; 790 file->f_mapping = inode->i_mapping; 791 file->f_op = &hugetlbfs_file_operations; 792 file->f_mode = FMODE_WRITE | FMODE_READ; 793 return file; 794 795 out_inode: 796 iput(inode); 797 out_file: 798 put_filp(file); 799 out_dentry: 800 dput(dentry); 801 out_shm_unlock: 802 user_shm_unlock(size, current->user); 803 return ERR_PTR(error); 804 } 805 806 static int __init init_hugetlbfs_fs(void) 807 { 808 int error; 809 struct vfsmount *vfsmount; 810 811 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache", 812 sizeof(struct hugetlbfs_inode_info), 813 0, 0, init_once, NULL); 814 if (hugetlbfs_inode_cachep == NULL) 815 return -ENOMEM; 816 817 error = register_filesystem(&hugetlbfs_fs_type); 818 if (error) 819 goto out; 820 821 vfsmount = kern_mount(&hugetlbfs_fs_type); 822 823 if (!IS_ERR(vfsmount)) { 824 hugetlbfs_vfsmount = vfsmount; 825 return 0; 826 } 827 828 error = PTR_ERR(vfsmount); 829 830 out: 831 if (error) 832 kmem_cache_destroy(hugetlbfs_inode_cachep); 833 return error; 834 } 835 836 static void __exit exit_hugetlbfs_fs(void) 837 { 838 kmem_cache_destroy(hugetlbfs_inode_cachep); 839 unregister_filesystem(&hugetlbfs_fs_type); 840 } 841 842 module_init(init_hugetlbfs_fs) 843 module_exit(exit_hugetlbfs_fs) 844 845 MODULE_LICENSE("GPL"); 846