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 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 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode); 63 loff_t len, vma_len; 64 int ret; 65 66 if (vma->vm_pgoff & (HPAGE_SIZE / PAGE_SIZE - 1)) 67 return -EINVAL; 68 69 if (vma->vm_start & ~HPAGE_MASK) 70 return -EINVAL; 71 72 if (vma->vm_end & ~HPAGE_MASK) 73 return -EINVAL; 74 75 if (vma->vm_end - vma->vm_start < HPAGE_SIZE) 76 return -EINVAL; 77 78 vma_len = (loff_t)(vma->vm_end - vma->vm_start); 79 80 mutex_lock(&inode->i_mutex); 81 file_accessed(file); 82 vma->vm_flags |= VM_HUGETLB | VM_RESERVED; 83 vma->vm_ops = &hugetlb_vm_ops; 84 85 ret = -ENOMEM; 86 len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); 87 if (!(vma->vm_flags & VM_WRITE) && len > inode->i_size) 88 goto out; 89 90 if (vma->vm_flags & VM_MAYSHARE) 91 if (hugetlb_extend_reservation(info, len >> HPAGE_SHIFT) != 0) 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; 199 200 hugetlb_truncate_reservation(HUGETLBFS_I(inode), 201 lstart >> HPAGE_SHIFT); 202 if (!mapping->nrpages) 203 return; 204 pagevec_init(&pvec, 0); 205 next = start; 206 while (1) { 207 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { 208 if (next == start) 209 break; 210 next = start; 211 continue; 212 } 213 214 for (i = 0; i < pagevec_count(&pvec); ++i) { 215 struct page *page = pvec.pages[i]; 216 217 lock_page(page); 218 if (page->index > next) 219 next = page->index; 220 ++next; 221 truncate_huge_page(page); 222 unlock_page(page); 223 hugetlb_put_quota(mapping); 224 } 225 huge_pagevec_release(&pvec); 226 } 227 BUG_ON(!lstart && mapping->nrpages); 228 } 229 230 static void hugetlbfs_delete_inode(struct inode *inode) 231 { 232 truncate_hugepages(inode, 0); 233 clear_inode(inode); 234 } 235 236 static void hugetlbfs_forget_inode(struct inode *inode) 237 { 238 struct super_block *sb = inode->i_sb; 239 240 if (!hlist_unhashed(&inode->i_hash)) { 241 if (!(inode->i_state & (I_DIRTY|I_LOCK))) 242 list_move(&inode->i_list, &inode_unused); 243 inodes_stat.nr_unused++; 244 if (!sb || (sb->s_flags & MS_ACTIVE)) { 245 spin_unlock(&inode_lock); 246 return; 247 } 248 inode->i_state |= I_WILL_FREE; 249 spin_unlock(&inode_lock); 250 /* 251 * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK 252 * in our backing_dev_info. 253 */ 254 write_inode_now(inode, 1); 255 spin_lock(&inode_lock); 256 inode->i_state &= ~I_WILL_FREE; 257 inodes_stat.nr_unused--; 258 hlist_del_init(&inode->i_hash); 259 } 260 list_del_init(&inode->i_list); 261 list_del_init(&inode->i_sb_list); 262 inode->i_state |= I_FREEING; 263 inodes_stat.nr_inodes--; 264 spin_unlock(&inode_lock); 265 truncate_hugepages(inode, 0); 266 clear_inode(inode); 267 destroy_inode(inode); 268 } 269 270 static void hugetlbfs_drop_inode(struct inode *inode) 271 { 272 if (!inode->i_nlink) 273 generic_delete_inode(inode); 274 else 275 hugetlbfs_forget_inode(inode); 276 } 277 278 /* 279 * h_pgoff is in HPAGE_SIZE units. 280 * vma->vm_pgoff is in PAGE_SIZE units. 281 */ 282 static inline void 283 hugetlb_vmtruncate_list(struct prio_tree_root *root, unsigned long h_pgoff) 284 { 285 struct vm_area_struct *vma; 286 struct prio_tree_iter iter; 287 288 vma_prio_tree_foreach(vma, &iter, root, h_pgoff, ULONG_MAX) { 289 unsigned long h_vm_pgoff; 290 unsigned long v_offset; 291 292 h_vm_pgoff = vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT); 293 v_offset = (h_pgoff - h_vm_pgoff) << HPAGE_SHIFT; 294 /* 295 * Is this VMA fully outside the truncation point? 296 */ 297 if (h_vm_pgoff >= h_pgoff) 298 v_offset = 0; 299 300 unmap_hugepage_range(vma, 301 vma->vm_start + v_offset, vma->vm_end); 302 } 303 } 304 305 /* 306 * Expanding truncates are not allowed. 307 */ 308 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset) 309 { 310 unsigned long pgoff; 311 struct address_space *mapping = inode->i_mapping; 312 313 if (offset > inode->i_size) 314 return -EINVAL; 315 316 BUG_ON(offset & ~HPAGE_MASK); 317 pgoff = offset >> HPAGE_SHIFT; 318 319 inode->i_size = offset; 320 spin_lock(&mapping->i_mmap_lock); 321 if (!prio_tree_empty(&mapping->i_mmap)) 322 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff); 323 spin_unlock(&mapping->i_mmap_lock); 324 truncate_hugepages(inode, offset); 325 return 0; 326 } 327 328 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr) 329 { 330 struct inode *inode = dentry->d_inode; 331 int error; 332 unsigned int ia_valid = attr->ia_valid; 333 334 BUG_ON(!inode); 335 336 error = inode_change_ok(inode, attr); 337 if (error) 338 goto out; 339 340 if (ia_valid & ATTR_SIZE) { 341 error = -EINVAL; 342 if (!(attr->ia_size & ~HPAGE_MASK)) 343 error = hugetlb_vmtruncate(inode, attr->ia_size); 344 if (error) 345 goto out; 346 attr->ia_valid &= ~ATTR_SIZE; 347 } 348 error = inode_setattr(inode, attr); 349 out: 350 return error; 351 } 352 353 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid, 354 gid_t gid, int mode, dev_t dev) 355 { 356 struct inode *inode; 357 358 inode = new_inode(sb); 359 if (inode) { 360 struct hugetlbfs_inode_info *info; 361 inode->i_mode = mode; 362 inode->i_uid = uid; 363 inode->i_gid = gid; 364 inode->i_blksize = HPAGE_SIZE; 365 inode->i_blocks = 0; 366 inode->i_mapping->a_ops = &hugetlbfs_aops; 367 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info; 368 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 369 info = HUGETLBFS_I(inode); 370 mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, NULL); 371 switch (mode & S_IFMT) { 372 default: 373 init_special_inode(inode, mode, dev); 374 break; 375 case S_IFREG: 376 inode->i_op = &hugetlbfs_inode_operations; 377 inode->i_fop = &hugetlbfs_file_operations; 378 break; 379 case S_IFDIR: 380 inode->i_op = &hugetlbfs_dir_inode_operations; 381 inode->i_fop = &simple_dir_operations; 382 383 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 384 inode->i_nlink++; 385 break; 386 case S_IFLNK: 387 inode->i_op = &page_symlink_inode_operations; 388 break; 389 } 390 } 391 return inode; 392 } 393 394 /* 395 * File creation. Allocate an inode, and we're done.. 396 */ 397 static int hugetlbfs_mknod(struct inode *dir, 398 struct dentry *dentry, int mode, dev_t dev) 399 { 400 struct inode *inode; 401 int error = -ENOSPC; 402 gid_t gid; 403 404 if (dir->i_mode & S_ISGID) { 405 gid = dir->i_gid; 406 if (S_ISDIR(mode)) 407 mode |= S_ISGID; 408 } else { 409 gid = current->fsgid; 410 } 411 inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev); 412 if (inode) { 413 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 414 d_instantiate(dentry, inode); 415 dget(dentry); /* Extra count - pin the dentry in core */ 416 error = 0; 417 } 418 return error; 419 } 420 421 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) 422 { 423 int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0); 424 if (!retval) 425 dir->i_nlink++; 426 return retval; 427 } 428 429 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd) 430 { 431 return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0); 432 } 433 434 static int hugetlbfs_symlink(struct inode *dir, 435 struct dentry *dentry, const char *symname) 436 { 437 struct inode *inode; 438 int error = -ENOSPC; 439 gid_t gid; 440 441 if (dir->i_mode & S_ISGID) 442 gid = dir->i_gid; 443 else 444 gid = current->fsgid; 445 446 inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, 447 gid, S_IFLNK|S_IRWXUGO, 0); 448 if (inode) { 449 int l = strlen(symname)+1; 450 error = page_symlink(inode, symname, l); 451 if (!error) { 452 d_instantiate(dentry, inode); 453 dget(dentry); 454 } else 455 iput(inode); 456 } 457 dir->i_ctime = dir->i_mtime = CURRENT_TIME; 458 459 return error; 460 } 461 462 /* 463 * For direct-IO reads into hugetlb pages 464 */ 465 static int hugetlbfs_set_page_dirty(struct page *page) 466 { 467 return 0; 468 } 469 470 static int hugetlbfs_statfs(struct super_block *sb, struct kstatfs *buf) 471 { 472 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb); 473 474 buf->f_type = HUGETLBFS_MAGIC; 475 buf->f_bsize = HPAGE_SIZE; 476 if (sbinfo) { 477 spin_lock(&sbinfo->stat_lock); 478 /* If no limits set, just report 0 for max/free/used 479 * blocks, like simple_statfs() */ 480 if (sbinfo->max_blocks >= 0) { 481 buf->f_blocks = sbinfo->max_blocks; 482 buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; 483 buf->f_files = sbinfo->max_inodes; 484 buf->f_ffree = sbinfo->free_inodes; 485 } 486 spin_unlock(&sbinfo->stat_lock); 487 } 488 buf->f_namelen = NAME_MAX; 489 return 0; 490 } 491 492 static void hugetlbfs_put_super(struct super_block *sb) 493 { 494 struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb); 495 496 if (sbi) { 497 sb->s_fs_info = NULL; 498 kfree(sbi); 499 } 500 } 501 502 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo) 503 { 504 if (sbinfo->free_inodes >= 0) { 505 spin_lock(&sbinfo->stat_lock); 506 if (unlikely(!sbinfo->free_inodes)) { 507 spin_unlock(&sbinfo->stat_lock); 508 return 0; 509 } 510 sbinfo->free_inodes--; 511 spin_unlock(&sbinfo->stat_lock); 512 } 513 514 return 1; 515 } 516 517 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo) 518 { 519 if (sbinfo->free_inodes >= 0) { 520 spin_lock(&sbinfo->stat_lock); 521 sbinfo->free_inodes++; 522 spin_unlock(&sbinfo->stat_lock); 523 } 524 } 525 526 527 static kmem_cache_t *hugetlbfs_inode_cachep; 528 529 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb) 530 { 531 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb); 532 struct hugetlbfs_inode_info *p; 533 534 if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo))) 535 return NULL; 536 p = kmem_cache_alloc(hugetlbfs_inode_cachep, SLAB_KERNEL); 537 if (unlikely(!p)) { 538 hugetlbfs_inc_free_inodes(sbinfo); 539 return NULL; 540 } 541 p->prereserved_hpages = 0; 542 return &p->vfs_inode; 543 } 544 545 static void hugetlbfs_destroy_inode(struct inode *inode) 546 { 547 hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb)); 548 mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy); 549 kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode)); 550 } 551 552 static struct address_space_operations hugetlbfs_aops = { 553 .readpage = hugetlbfs_readpage, 554 .prepare_write = hugetlbfs_prepare_write, 555 .commit_write = hugetlbfs_commit_write, 556 .set_page_dirty = hugetlbfs_set_page_dirty, 557 }; 558 559 560 static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags) 561 { 562 struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo; 563 564 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == 565 SLAB_CTOR_CONSTRUCTOR) 566 inode_init_once(&ei->vfs_inode); 567 } 568 569 const struct file_operations hugetlbfs_file_operations = { 570 .mmap = hugetlbfs_file_mmap, 571 .fsync = simple_sync_file, 572 .get_unmapped_area = hugetlb_get_unmapped_area, 573 }; 574 575 static struct inode_operations hugetlbfs_dir_inode_operations = { 576 .create = hugetlbfs_create, 577 .lookup = simple_lookup, 578 .link = simple_link, 579 .unlink = simple_unlink, 580 .symlink = hugetlbfs_symlink, 581 .mkdir = hugetlbfs_mkdir, 582 .rmdir = simple_rmdir, 583 .mknod = hugetlbfs_mknod, 584 .rename = simple_rename, 585 .setattr = hugetlbfs_setattr, 586 }; 587 588 static struct inode_operations hugetlbfs_inode_operations = { 589 .setattr = hugetlbfs_setattr, 590 }; 591 592 static struct super_operations hugetlbfs_ops = { 593 .alloc_inode = hugetlbfs_alloc_inode, 594 .destroy_inode = hugetlbfs_destroy_inode, 595 .statfs = hugetlbfs_statfs, 596 .delete_inode = hugetlbfs_delete_inode, 597 .drop_inode = hugetlbfs_drop_inode, 598 .put_super = hugetlbfs_put_super, 599 }; 600 601 static int 602 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig) 603 { 604 char *opt, *value, *rest; 605 606 if (!options) 607 return 0; 608 while ((opt = strsep(&options, ",")) != NULL) { 609 if (!*opt) 610 continue; 611 612 value = strchr(opt, '='); 613 if (!value || !*value) 614 return -EINVAL; 615 else 616 *value++ = '\0'; 617 618 if (!strcmp(opt, "uid")) 619 pconfig->uid = simple_strtoul(value, &value, 0); 620 else if (!strcmp(opt, "gid")) 621 pconfig->gid = simple_strtoul(value, &value, 0); 622 else if (!strcmp(opt, "mode")) 623 pconfig->mode = simple_strtoul(value,&value,0) & 0777U; 624 else if (!strcmp(opt, "size")) { 625 unsigned long long size = memparse(value, &rest); 626 if (*rest == '%') { 627 size <<= HPAGE_SHIFT; 628 size *= max_huge_pages; 629 do_div(size, 100); 630 rest++; 631 } 632 size &= HPAGE_MASK; 633 pconfig->nr_blocks = (size >> HPAGE_SHIFT); 634 value = rest; 635 } else if (!strcmp(opt,"nr_inodes")) { 636 pconfig->nr_inodes = memparse(value, &rest); 637 value = rest; 638 } else 639 return -EINVAL; 640 641 if (*value) 642 return -EINVAL; 643 } 644 return 0; 645 } 646 647 static int 648 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent) 649 { 650 struct inode * inode; 651 struct dentry * root; 652 int ret; 653 struct hugetlbfs_config config; 654 struct hugetlbfs_sb_info *sbinfo; 655 656 config.nr_blocks = -1; /* No limit on size by default */ 657 config.nr_inodes = -1; /* No limit on number of inodes by default */ 658 config.uid = current->fsuid; 659 config.gid = current->fsgid; 660 config.mode = 0755; 661 ret = hugetlbfs_parse_options(data, &config); 662 663 if (ret) 664 return ret; 665 666 sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL); 667 if (!sbinfo) 668 return -ENOMEM; 669 sb->s_fs_info = sbinfo; 670 spin_lock_init(&sbinfo->stat_lock); 671 sbinfo->max_blocks = config.nr_blocks; 672 sbinfo->free_blocks = config.nr_blocks; 673 sbinfo->max_inodes = config.nr_inodes; 674 sbinfo->free_inodes = config.nr_inodes; 675 sb->s_maxbytes = MAX_LFS_FILESIZE; 676 sb->s_blocksize = HPAGE_SIZE; 677 sb->s_blocksize_bits = HPAGE_SHIFT; 678 sb->s_magic = HUGETLBFS_MAGIC; 679 sb->s_op = &hugetlbfs_ops; 680 sb->s_time_gran = 1; 681 inode = hugetlbfs_get_inode(sb, config.uid, config.gid, 682 S_IFDIR | config.mode, 0); 683 if (!inode) 684 goto out_free; 685 686 root = d_alloc_root(inode); 687 if (!root) { 688 iput(inode); 689 goto out_free; 690 } 691 sb->s_root = root; 692 return 0; 693 out_free: 694 kfree(sbinfo); 695 return -ENOMEM; 696 } 697 698 int hugetlb_get_quota(struct address_space *mapping) 699 { 700 int ret = 0; 701 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb); 702 703 if (sbinfo->free_blocks > -1) { 704 spin_lock(&sbinfo->stat_lock); 705 if (sbinfo->free_blocks > 0) 706 sbinfo->free_blocks--; 707 else 708 ret = -ENOMEM; 709 spin_unlock(&sbinfo->stat_lock); 710 } 711 712 return ret; 713 } 714 715 void hugetlb_put_quota(struct address_space *mapping) 716 { 717 struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb); 718 719 if (sbinfo->free_blocks > -1) { 720 spin_lock(&sbinfo->stat_lock); 721 sbinfo->free_blocks++; 722 spin_unlock(&sbinfo->stat_lock); 723 } 724 } 725 726 static struct super_block *hugetlbfs_get_sb(struct file_system_type *fs_type, 727 int flags, const char *dev_name, void *data) 728 { 729 return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super); 730 } 731 732 static struct file_system_type hugetlbfs_fs_type = { 733 .name = "hugetlbfs", 734 .get_sb = hugetlbfs_get_sb, 735 .kill_sb = kill_litter_super, 736 }; 737 738 static struct vfsmount *hugetlbfs_vfsmount; 739 740 static int can_do_hugetlb_shm(void) 741 { 742 return likely(capable(CAP_IPC_LOCK) || 743 in_group_p(sysctl_hugetlb_shm_group) || 744 can_do_mlock()); 745 } 746 747 struct file *hugetlb_zero_setup(size_t size) 748 { 749 int error = -ENOMEM; 750 struct file *file; 751 struct inode *inode; 752 struct dentry *dentry, *root; 753 struct qstr quick_string; 754 char buf[16]; 755 static atomic_t counter; 756 757 if (!can_do_hugetlb_shm()) 758 return ERR_PTR(-EPERM); 759 760 if (!user_shm_lock(size, current->user)) 761 return ERR_PTR(-ENOMEM); 762 763 root = hugetlbfs_vfsmount->mnt_root; 764 snprintf(buf, 16, "%u", atomic_inc_return(&counter)); 765 quick_string.name = buf; 766 quick_string.len = strlen(quick_string.name); 767 quick_string.hash = 0; 768 dentry = d_alloc(root, &quick_string); 769 if (!dentry) 770 goto out_shm_unlock; 771 772 error = -ENFILE; 773 file = get_empty_filp(); 774 if (!file) 775 goto out_dentry; 776 777 error = -ENOSPC; 778 inode = hugetlbfs_get_inode(root->d_sb, current->fsuid, 779 current->fsgid, S_IFREG | S_IRWXUGO, 0); 780 if (!inode) 781 goto out_file; 782 783 error = -ENOMEM; 784 if (hugetlb_extend_reservation(HUGETLBFS_I(inode), 785 size >> HPAGE_SHIFT) != 0) 786 goto out_inode; 787 788 d_instantiate(dentry, inode); 789 inode->i_size = size; 790 inode->i_nlink = 0; 791 file->f_vfsmnt = mntget(hugetlbfs_vfsmount); 792 file->f_dentry = dentry; 793 file->f_mapping = inode->i_mapping; 794 file->f_op = &hugetlbfs_file_operations; 795 file->f_mode = FMODE_WRITE | FMODE_READ; 796 return file; 797 798 out_inode: 799 iput(inode); 800 out_file: 801 put_filp(file); 802 out_dentry: 803 dput(dentry); 804 out_shm_unlock: 805 user_shm_unlock(size, current->user); 806 return ERR_PTR(error); 807 } 808 809 static int __init init_hugetlbfs_fs(void) 810 { 811 int error; 812 struct vfsmount *vfsmount; 813 814 hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache", 815 sizeof(struct hugetlbfs_inode_info), 816 0, 0, init_once, NULL); 817 if (hugetlbfs_inode_cachep == NULL) 818 return -ENOMEM; 819 820 error = register_filesystem(&hugetlbfs_fs_type); 821 if (error) 822 goto out; 823 824 vfsmount = kern_mount(&hugetlbfs_fs_type); 825 826 if (!IS_ERR(vfsmount)) { 827 hugetlbfs_vfsmount = vfsmount; 828 return 0; 829 } 830 831 error = PTR_ERR(vfsmount); 832 833 out: 834 if (error) 835 kmem_cache_destroy(hugetlbfs_inode_cachep); 836 return error; 837 } 838 839 static void __exit exit_hugetlbfs_fs(void) 840 { 841 kmem_cache_destroy(hugetlbfs_inode_cachep); 842 unregister_filesystem(&hugetlbfs_fs_type); 843 } 844 845 module_init(init_hugetlbfs_fs) 846 module_exit(exit_hugetlbfs_fs) 847 848 MODULE_LICENSE("GPL"); 849