fs/hugetlbfs/inode.c

   1 /*
   2  * hugetlbpage-backed filesystem.  Based on ramfs.
   3  *
   4  * Nadia Yvette Chambers, 2002
   5  *
   6  * Copyright (C) 2002 Linus Torvalds.
   7  * License: GPL
   8  */
   9
  10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/thread_info.h>
  13 #include <asm/current.h>
  14 #include <linux/sched.h>                /* remove ASAP */
  15 #include <linux/falloc.h>
  16 #include <linux/fs.h>
  17 #include <linux/mount.h>
  18 #include <linux/file.h>
  19 #include <linux/kernel.h>
  20 #include <linux/writeback.h>
  21 #include <linux/pagemap.h>
  22 #include <linux/highmem.h>
  23 #include <linux/init.h>
  24 #include <linux/string.h>
  25 #include <linux/capability.h>
  26 #include <linux/ctype.h>
  27 #include <linux/backing-dev.h>
  28 #include <linux/hugetlb.h>
  29 #include <linux/pagevec.h>
  30 #include <linux/parser.h>
  31 #include <linux/mman.h>
  32 #include <linux/slab.h>
  33 #include <linux/dnotify.h>
  34 #include <linux/statfs.h>
  35 #include <linux/security.h>
  36 #include <linux/magic.h>
  37 #include <linux/migrate.h>
  38 #include <linux/uio.h>
  39
  40 #include <asm/uaccess.h>
  41
  42 static const struct super_operations hugetlbfs_ops;
  43 static const struct address_space_operations hugetlbfs_aops;
  44 const struct file_operations hugetlbfs_file_operations;
  45 static const struct inode_operations hugetlbfs_dir_inode_operations;
  46 static const struct inode_operations hugetlbfs_inode_operations;
  47
  48 struct hugetlbfs_config {
  49         kuid_t   uid;
  50         kgid_t   gid;
  51         umode_t mode;
  52         long    max_hpages;
  53         long    nr_inodes;
  54         struct hstate *hstate;
  55         long    min_hpages;
  56 };
  57
  58 struct hugetlbfs_inode_info {
  59         struct shared_policy policy;
  60         struct inode vfs_inode;
  61 };
  62
  63 static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
  64 {
  65         return container_of(inode, struct hugetlbfs_inode_info, vfs_inode);
  66 }
  67
  68 int sysctl_hugetlb_shm_group;
  69
  70 enum {
  71         Opt_size, Opt_nr_inodes,
  72         Opt_mode, Opt_uid, Opt_gid,
  73         Opt_pagesize, Opt_min_size,
  74         Opt_err,
  75 };
  76
  77 static const match_table_t tokens = {
  78         {Opt_size,      "size=%s"},
  79         {Opt_nr_inodes, "nr_inodes=%s"},
  80         {Opt_mode,      "mode=%o"},
  81         {Opt_uid,       "uid=%u"},
  82         {Opt_gid,       "gid=%u"},
  83         {Opt_pagesize,  "pagesize=%s"},
  84         {Opt_min_size,  "min_size=%s"},
  85         {Opt_err,       NULL},
  86 };
  87
  88 #ifdef CONFIG_NUMA
  89 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
  90                                         struct inode *inode, pgoff_t index)
  91 {
  92         vma->vm_policy = mpol_shared_policy_lookup(&HUGETLBFS_I(inode)->policy,
  93                                                         index);
  94 }
  95
  96 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
  97 {
  98         mpol_cond_put(vma->vm_policy);
  99 }
 100 #else
 101 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
 102                                         struct inode *inode, pgoff_t index)
 103 {
 104 }
 105
 106 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
 107 {
 108 }
 109 #endif
 110
 111 static void huge_pagevec_release(struct pagevec *pvec)
 112 {
 113         int i;
 114
 115         for (i = 0; i < pagevec_count(pvec); ++i)
 116                 put_page(pvec->pages[i]);
 117
 118         pagevec_reinit(pvec);
 119 }
 120
 121 /*
 122  * Mask used when checking the page offset value passed in via system
 123  * calls.  This value will be converted to a loff_t which is signed.
 124  * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the
 125  * value.  The extra bit (- 1 in the shift value) is to take the sign
 126  * bit into account.
 127  */
 128 #define PGOFF_LOFFT_MAX \
 129         (((1UL << (PAGE_SHIFT + 1)) - 1) <<  (BITS_PER_LONG - (PAGE_SHIFT + 1)))
 130
 131 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 132 {
 133         struct inode *inode = file_inode(file);
 134         loff_t len, vma_len;
 135         int ret;
 136         struct hstate *h = hstate_file(file);
 137
 138         /*
 139          * vma address alignment (but not the pgoff alignment) has
 140          * already been checked by prepare_hugepage_range.  If you add
 141          * any error returns here, do so after setting VM_HUGETLB, so
 142          * is_vm_hugetlb_page tests below unmap_region go the right
 143          * way when do_mmap_pgoff unwinds (may be important on powerpc
 144          * and ia64).
 145          */
 146         vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND;
 147         vma->vm_ops = &hugetlb_vm_ops;
 148
 149         /*
 150          * page based offset in vm_pgoff could be sufficiently large to
 151          * overflow a loff_t when converted to byte offset.  This can
 152          * only happen on architectures where sizeof(loff_t) ==
 153          * sizeof(unsigned long).  So, only check in those instances.
 154          */
 155         if (sizeof(unsigned long) == sizeof(loff_t)) {
 156                 if (vma->vm_pgoff & PGOFF_LOFFT_MAX)
 157                         return -EINVAL;
 158         }
 159
 160         /* must be huge page aligned */
 161         if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
 162                 return -EINVAL;
 163
 164         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
 165         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 166         /* check for overflow */
 167         if (len < vma_len)
 168                 return -EINVAL;
 169
 170         inode_lock(inode);
 171         file_accessed(file);
 172
 173         ret = -ENOMEM;
 174         if (hugetlb_reserve_pages(inode,
 175                                 vma->vm_pgoff >> huge_page_order(h),
 176                                 len >> huge_page_shift(h), vma,
 177                                 vma->vm_flags))
 178                 goto out;
 179
 180         ret = 0;
 181         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
 182                 i_size_write(inode, len);
 183 out:
 184         inode_unlock(inode);
 185
 186         return ret;
 187 }
 188
 189 /*
 190  * Called under down_write(mmap_sem).
 191  */
 192
 193 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 194 static unsigned long
 195 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 196                 unsigned long len, unsigned long pgoff, unsigned long flags)
 197 {
 198         struct mm_struct *mm = current->mm;
 199         struct vm_area_struct *vma;
 200         struct hstate *h = hstate_file(file);
 201         struct vm_unmapped_area_info info;
 202
 203         if (len & ~huge_page_mask(h))
 204                 return -EINVAL;
 205         if (len > TASK_SIZE)
 206                 return -ENOMEM;
 207
 208         if (flags & MAP_FIXED) {
 209                 if (prepare_hugepage_range(file, addr, len))
 210                         return -EINVAL;
 211                 return addr;
 212         }
 213
 214         if (addr) {
 215                 addr = ALIGN(addr, huge_page_size(h));
 216                 vma = find_vma(mm, addr);
 217                 if (TASK_SIZE - len >= addr &&
 218                     (!vma || addr + len <= vm_start_gap(vma)))
 219                         return addr;
 220         }
 221
 222         info.flags = 0;
 223         info.length = len;
 224         info.low_limit = TASK_UNMAPPED_BASE;
 225         info.high_limit = TASK_SIZE;
 226         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 227         info.align_offset = 0;
 228         return vm_unmapped_area(&info);
 229 }
 230 #endif
 231
 232 static size_t
 233 hugetlbfs_read_actor(struct page *page, unsigned long offset,
 234                         struct iov_iter *to, unsigned long size)
 235 {
 236         size_t copied = 0;
 237         int i, chunksize;
 238
 239         /* Find which 4k chunk and offset with in that chunk */
 240         i = offset >> PAGE_SHIFT;
 241         offset = offset & ~PAGE_MASK;
 242
 243         while (size) {
 244                 size_t n;
 245                 chunksize = PAGE_SIZE;
 246                 if (offset)
 247                         chunksize -= offset;
 248                 if (chunksize > size)
 249                         chunksize = size;
 250                 n = copy_page_to_iter(&page[i], offset, chunksize, to);
 251                 copied += n;
 252                 if (n != chunksize)
 253                         return copied;
 254                 offset = 0;
 255                 size -= chunksize;
 256                 i++;
 257         }
 258         return copied;
 259 }
 260
 261 /*
 262  * Support for read() - Find the page attached to f_mapping and copy out the
 263  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
 264  * since it has PAGE_SIZE assumptions.
 265  */
 266 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
 267 {
 268         struct file *file = iocb->ki_filp;
 269         struct hstate *h = hstate_file(file);
 270         struct address_space *mapping = file->f_mapping;
 271         struct inode *inode = mapping->host;
 272         unsigned long index = iocb->ki_pos >> huge_page_shift(h);
 273         unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
 274         unsigned long end_index;
 275         loff_t isize;
 276         ssize_t retval = 0;
 277
 278         while (iov_iter_count(to)) {
 279                 struct page *page;
 280                 size_t nr, copied;
 281
 282                 /* nr is the maximum number of bytes to copy from this page */
 283                 nr = huge_page_size(h);
 284                 isize = i_size_read(inode);
 285                 if (!isize)
 286                         break;
 287                 end_index = (isize - 1) >> huge_page_shift(h);
 288                 if (index > end_index)
 289                         break;
 290                 if (index == end_index) {
 291                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
 292                         if (nr <= offset)
 293                                 break;
 294                 }
 295                 nr = nr - offset;
 296
 297                 /* Find the page */
 298                 page = find_lock_page(mapping, index);
 299                 if (unlikely(page == NULL)) {
 300                         /*
 301                          * We have a HOLE, zero out the user-buffer for the
 302                          * length of the hole or request.
 303                          */
 304                         copied = iov_iter_zero(nr, to);
 305                 } else {
 306                         unlock_page(page);
 307
 308                         /*
 309                          * We have the page, copy it to user space buffer.
 310                          */
 311                         copied = hugetlbfs_read_actor(page, offset, to, nr);
 312                         put_page(page);
 313                 }
 314                 offset += copied;
 315                 retval += copied;
 316                 if (copied != nr && iov_iter_count(to)) {
 317                         if (!retval)
 318                                 retval = -EFAULT;
 319                         break;
 320                 }
 321                 index += offset >> huge_page_shift(h);
 322                 offset &= ~huge_page_mask(h);
 323         }
 324         iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
 325         return retval;
 326 }
 327
 328 static int hugetlbfs_write_begin(struct file *file,
 329                         struct address_space *mapping,
 330                         loff_t pos, unsigned len, unsigned flags,
 331                         struct page **pagep, void **fsdata)
 332 {
 333         return -EINVAL;
 334 }
 335
 336 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
 337                         loff_t pos, unsigned len, unsigned copied,
 338                         struct page *page, void *fsdata)
 339 {
 340         BUG();
 341         return -EINVAL;
 342 }
 343
 344 static void remove_huge_page(struct page *page)
 345 {
 346         ClearPageDirty(page);
 347         ClearPageUptodate(page);
 348         delete_from_page_cache(page);
 349 }
 350
 351 static void
 352 hugetlb_vmdelete_list(struct rb_root *root, pgoff_t start, pgoff_t end)
 353 {
 354         struct vm_area_struct *vma;
 355
 356         /*
 357          * end == 0 indicates that the entire range after
 358          * start should be unmapped.
 359          */
 360         vma_interval_tree_foreach(vma, root, start, end ? end : ULONG_MAX) {
 361                 unsigned long v_offset;
 362                 unsigned long v_end;
 363
 364                 /*
 365                  * Can the expression below overflow on 32-bit arches?
 366                  * No, because the interval tree returns us only those vmas
 367                  * which overlap the truncated area starting at pgoff,
 368                  * and no vma on a 32-bit arch can span beyond the 4GB.
 369                  */
 370                 if (vma->vm_pgoff < start)
 371                         v_offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
 372                 else
 373                         v_offset = 0;
 374
 375                 if (!end)
 376                         v_end = vma->vm_end;
 377                 else {
 378                         v_end = ((end - vma->vm_pgoff) << PAGE_SHIFT)
 379                                                         + vma->vm_start;
 380                         if (v_end > vma->vm_end)
 381                                 v_end = vma->vm_end;
 382                 }
 383
 384                 unmap_hugepage_range(vma, vma->vm_start + v_offset, v_end,
 385                                                                         NULL);
 386         }
 387 }
 388
 389 /*
 390  * remove_inode_hugepages handles two distinct cases: truncation and hole
 391  * punch.  There are subtle differences in operation for each case.
 392  *
 393  * truncation is indicated by end of range being LLONG_MAX
 394  *      In this case, we first scan the range and release found pages.
 395  *      After releasing pages, hugetlb_unreserve_pages cleans up region/reserv
 396  *      maps and global counts.  Page faults can not race with truncation
 397  *      in this routine.  hugetlb_no_page() prevents page faults in the
 398  *      truncated range.  It checks i_size before allocation, and again after
 399  *      with the page table lock for the page held.  The same lock must be
 400  *      acquired to unmap a page.
 401  * hole punch is indicated if end is not LLONG_MAX
 402  *      In the hole punch case we scan the range and release found pages.
 403  *      Only when releasing a page is the associated region/reserv map
 404  *      deleted.  The region/reserv map for ranges without associated
 405  *      pages are not modified.  Page faults can race with hole punch.
 406  *      This is indicated if we find a mapped page.
 407  * Note: If the passed end of range value is beyond the end of file, but
 408  * not LLONG_MAX this routine still performs a hole punch operation.
 409  */
 410 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 411                                    loff_t lend)
 412 {
 413         struct hstate *h = hstate_inode(inode);
 414         struct address_space *mapping = &inode->i_data;
 415         const pgoff_t start = lstart >> huge_page_shift(h);
 416         const pgoff_t end = lend >> huge_page_shift(h);
 417         struct vm_area_struct pseudo_vma;
 418         struct pagevec pvec;
 419         pgoff_t next;
 420         int i, freed = 0;
 421         long lookup_nr = PAGEVEC_SIZE;
 422         bool truncate_op = (lend == LLONG_MAX);
 423
 424         memset(&pseudo_vma, 0, sizeof(struct vm_area_struct));
 425         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
 426         pagevec_init(&pvec, 0);
 427         next = start;
 428         while (next < end) {
 429                 /*
 430                  * Don't grab more pages than the number left in the range.
 431                  */
 432                 if (end - next < lookup_nr)
 433                         lookup_nr = end - next;
 434
 435                 /*
 436                  * When no more pages are found, we are done.
 437                  */
 438                 if (!pagevec_lookup(&pvec, mapping, next, lookup_nr))
 439                         break;
 440
 441                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 442                         struct page *page = pvec.pages[i];
 443                         u32 hash;
 444
 445                         /*
 446                          * The page (index) could be beyond end.  This is
 447                          * only possible in the punch hole case as end is
 448                          * max page offset in the truncate case.
 449                          */
 450                         next = page->index;
 451                         if (next >= end)
 452                                 break;
 453
 454                         hash = hugetlb_fault_mutex_hash(h, mapping, next);
 455                         mutex_lock(&hugetlb_fault_mutex_table[hash]);
 456
 457                         /*
 458                          * If page is mapped, it was faulted in after being
 459                          * unmapped in caller.  Unmap (again) now after taking
 460                          * the fault mutex.  The mutex will prevent faults
 461                          * until we finish removing the page.
 462                          *
 463                          * This race can only happen in the hole punch case.
 464                          * Getting here in a truncate operation is a bug.
 465                          */
 466                         if (unlikely(page_mapped(page))) {
 467                                 BUG_ON(truncate_op);
 468
 469                                 i_mmap_lock_write(mapping);
 470                                 hugetlb_vmdelete_list(&mapping->i_mmap,
 471                                         next * pages_per_huge_page(h),
 472                                         (next + 1) * pages_per_huge_page(h));
 473                                 i_mmap_unlock_write(mapping);
 474                         }
 475
 476                         lock_page(page);
 477                         /*
 478                          * We must free the huge page and remove from page
 479                          * cache (remove_huge_page) BEFORE removing the
 480                          * region/reserve map (hugetlb_unreserve_pages).  In
 481                          * rare out of memory conditions, removal of the
 482                          * region/reserve map could fail. Correspondingly,
 483                          * the subpool and global reserve usage count can need
 484                          * to be adjusted.
 485                          */
 486                         VM_BUG_ON(PagePrivate(page));
 487                         remove_huge_page(page);
 488                         freed++;
 489                         if (!truncate_op) {
 490                                 if (unlikely(hugetlb_unreserve_pages(inode,
 491                                                         next, next + 1, 1)))
 492                                         hugetlb_fix_reserve_counts(inode);
 493                         }
 494
 495                         unlock_page(page);
 496                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 497                 }
 498                 ++next;
 499                 huge_pagevec_release(&pvec);
 500                 cond_resched();
 501         }
 502
 503         if (truncate_op)
 504                 (void)hugetlb_unreserve_pages(inode, start, LONG_MAX, freed);
 505 }
 506
 507 static void hugetlbfs_evict_inode(struct inode *inode)
 508 {
 509         struct resv_map *resv_map;
 510
 511         remove_inode_hugepages(inode, 0, LLONG_MAX);
 512         resv_map = (struct resv_map *)inode->i_mapping->private_data;
 513         /* root inode doesn't have the resv_map, so we should check it */
 514         if (resv_map)
 515                 resv_map_release(&resv_map->refs);
 516         clear_inode(inode);
 517 }
 518
 519 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 520 {
 521         pgoff_t pgoff;
 522         struct address_space *mapping = inode->i_mapping;
 523         struct hstate *h = hstate_inode(inode);
 524
 525         BUG_ON(offset & ~huge_page_mask(h));
 526         pgoff = offset >> PAGE_SHIFT;
 527
 528         i_size_write(inode, offset);
 529         i_mmap_lock_write(mapping);
 530         if (!RB_EMPTY_ROOT(&mapping->i_mmap))
 531                 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0);
 532         i_mmap_unlock_write(mapping);
 533         remove_inode_hugepages(inode, offset, LLONG_MAX);
 534         return 0;
 535 }
 536
 537 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
 538 {
 539         struct hstate *h = hstate_inode(inode);
 540         loff_t hpage_size = huge_page_size(h);
 541         loff_t hole_start, hole_end;
 542
 543         /*
 544          * For hole punch round up the beginning offset of the hole and
 545          * round down the end.
 546          */
 547         hole_start = round_up(offset, hpage_size);
 548         hole_end = round_down(offset + len, hpage_size);
 549
 550         if (hole_end > hole_start) {
 551                 struct address_space *mapping = inode->i_mapping;
 552
 553                 inode_lock(inode);
 554                 i_mmap_lock_write(mapping);
 555                 if (!RB_EMPTY_ROOT(&mapping->i_mmap))
 556                         hugetlb_vmdelete_list(&mapping->i_mmap,
 557                                                 hole_start >> PAGE_SHIFT,
 558                                                 hole_end  >> PAGE_SHIFT);
 559                 i_mmap_unlock_write(mapping);
 560                 remove_inode_hugepages(inode, hole_start, hole_end);
 561                 inode_unlock(inode);
 562         }
 563
 564         return 0;
 565 }
 566
 567 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
 568                                 loff_t len)
 569 {
 570         struct inode *inode = file_inode(file);
 571         struct address_space *mapping = inode->i_mapping;
 572         struct hstate *h = hstate_inode(inode);
 573         struct vm_area_struct pseudo_vma;
 574         loff_t hpage_size = huge_page_size(h);
 575         unsigned long hpage_shift = huge_page_shift(h);
 576         pgoff_t start, index, end;
 577         int error;
 578         u32 hash;
 579
 580         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
 581                 return -EOPNOTSUPP;
 582
 583         if (mode & FALLOC_FL_PUNCH_HOLE)
 584                 return hugetlbfs_punch_hole(inode, offset, len);
 585
 586         /*
 587          * Default preallocate case.
 588          * For this range, start is rounded down and end is rounded up
 589          * as well as being converted to page offsets.
 590          */
 591         start = offset >> hpage_shift;
 592         end = (offset + len + hpage_size - 1) >> hpage_shift;
 593
 594         inode_lock(inode);
 595
 596         /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
 597         error = inode_newsize_ok(inode, offset + len);
 598         if (error)
 599                 goto out;
 600
 601         /*
 602          * Initialize a pseudo vma as this is required by the huge page
 603          * allocation routines.  If NUMA is configured, use page index
 604          * as input to create an allocation policy.
 605          */
 606         memset(&pseudo_vma, 0, sizeof(struct vm_area_struct));
 607         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
 608         pseudo_vma.vm_file = file;
 609
 610         for (index = start; index < end; index++) {
 611                 /*
 612                  * This is supposed to be the vaddr where the page is being
 613                  * faulted in, but we have no vaddr here.
 614                  */
 615                 struct page *page;
 616                 unsigned long addr;
 617                 int avoid_reserve = 0;
 618
 619                 cond_resched();
 620
 621                 /*
 622                  * fallocate(2) manpage permits EINTR; we may have been
 623                  * interrupted because we are using up too much memory.
 624                  */
 625                 if (signal_pending(current)) {
 626                         error = -EINTR;
 627                         break;
 628                 }
 629
 630                 /* Set numa allocation policy based on index */
 631                 hugetlb_set_vma_policy(&pseudo_vma, inode, index);
 632
 633                 /* addr is the offset within the file (zero based) */
 634                 addr = index * hpage_size;
 635
 636                 /* mutex taken here, fault path and hole punch */
 637                 hash = hugetlb_fault_mutex_hash(h, mapping, index);
 638                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
 639
 640                 /* See if already present in mapping to avoid alloc/free */
 641                 page = find_get_page(mapping, index);
 642                 if (page) {
 643                         put_page(page);
 644                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 645                         hugetlb_drop_vma_policy(&pseudo_vma);
 646                         continue;
 647                 }
 648
 649                 /* Allocate page and add to page cache */
 650                 page = alloc_huge_page(&pseudo_vma, addr, avoid_reserve);
 651                 hugetlb_drop_vma_policy(&pseudo_vma);
 652                 if (IS_ERR(page)) {
 653                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 654                         error = PTR_ERR(page);
 655                         goto out;
 656                 }
 657                 clear_huge_page(page, addr, pages_per_huge_page(h));
 658                 __SetPageUptodate(page);
 659                 error = huge_add_to_page_cache(page, mapping, index);
 660                 if (unlikely(error)) {
 661                         put_page(page);
 662                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 663                         goto out;
 664                 }
 665
 666                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 667
 668                 set_page_huge_active(page);
 669                 /*
 670                  * put_page() due to reference from alloc_huge_page()
 671                  * unlock_page because locked by add_to_page_cache()
 672                  */
 673                 put_page(page);
 674                 unlock_page(page);
 675         }
 676
 677         if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
 678                 i_size_write(inode, offset + len);
 679         inode->i_ctime = current_time(inode);
 680 out:
 681         inode_unlock(inode);
 682         return error;
 683 }
 684
 685 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 686 {
 687         struct inode *inode = d_inode(dentry);
 688         struct hstate *h = hstate_inode(inode);
 689         int error;
 690         unsigned int ia_valid = attr->ia_valid;
 691
 692         BUG_ON(!inode);
 693
 694         error = setattr_prepare(dentry, attr);
 695         if (error)
 696                 return error;
 697
 698         if (ia_valid & ATTR_SIZE) {
 699                 error = -EINVAL;
 700                 if (attr->ia_size & ~huge_page_mask(h))
 701                         return -EINVAL;
 702                 error = hugetlb_vmtruncate(inode, attr->ia_size);
 703                 if (error)
 704                         return error;
 705         }
 706
 707         setattr_copy(inode, attr);
 708         mark_inode_dirty(inode);
 709         return 0;
 710 }
 711
 712 static struct inode *hugetlbfs_get_root(struct super_block *sb,
 713                                         struct hugetlbfs_config *config)
 714 {
 715         struct inode *inode;
 716
 717         inode = new_inode(sb);
 718         if (inode) {
 719                 inode->i_ino = get_next_ino();
 720                 inode->i_mode = S_IFDIR | config->mode;
 721                 inode->i_uid = config->uid;
 722                 inode->i_gid = config->gid;
 723                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 724                 inode->i_op = &hugetlbfs_dir_inode_operations;
 725                 inode->i_fop = &simple_dir_operations;
 726                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
 727                 inc_nlink(inode);
 728                 lockdep_annotate_inode_mutex_key(inode);
 729         }
 730         return inode;
 731 }
 732
 733 /*
 734  * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
 735  * be taken from reclaim -- unlike regular filesystems. This needs an
 736  * annotation because huge_pmd_share() does an allocation under hugetlb's
 737  * i_mmap_rwsem.
 738  */
 739 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
 740
 741 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 742                                         struct inode *dir,
 743                                         umode_t mode, dev_t dev)
 744 {
 745         struct inode *inode;
 746         struct resv_map *resv_map = NULL;
 747
 748         /*
 749          * Reserve maps are only needed for inodes that can have associated
 750          * page allocations.
 751          */
 752         if (S_ISREG(mode) || S_ISLNK(mode)) {
 753                 resv_map = resv_map_alloc();
 754                 if (!resv_map)
 755                         return NULL;
 756         }
 757
 758         inode = new_inode(sb);
 759         if (inode) {
 760                 inode->i_ino = get_next_ino();
 761                 inode_init_owner(inode, dir, mode);
 762                 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
 763                                 &hugetlbfs_i_mmap_rwsem_key);
 764                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 765                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 766                 inode->i_mapping->private_data = resv_map;
 767                 switch (mode & S_IFMT) {
 768                 default:
 769                         init_special_inode(inode, mode, dev);
 770                         break;
 771                 case S_IFREG:
 772                         inode->i_op = &hugetlbfs_inode_operations;
 773                         inode->i_fop = &hugetlbfs_file_operations;
 774                         break;
 775                 case S_IFDIR:
 776                         inode->i_op = &hugetlbfs_dir_inode_operations;
 777                         inode->i_fop = &simple_dir_operations;
 778
 779                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 780                         inc_nlink(inode);
 781                         break;
 782                 case S_IFLNK:
 783                         inode->i_op = &page_symlink_inode_operations;
 784                         inode_nohighmem(inode);
 785                         break;
 786                 }
 787                 lockdep_annotate_inode_mutex_key(inode);
 788         } else {
 789                 if (resv_map)
 790                         kref_put(&resv_map->refs, resv_map_release);
 791         }
 792
 793         return inode;
 794 }
 795
 796 /*
 797  * File creation. Allocate an inode, and we're done..
 798  */
 799 static int hugetlbfs_mknod(struct inode *dir,
 800                         struct dentry *dentry, umode_t mode, dev_t dev)
 801 {
 802         struct inode *inode;
 803         int error = -ENOSPC;
 804
 805         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
 806         if (inode) {
 807                 dir->i_ctime = dir->i_mtime = current_time(dir);
 808                 d_instantiate(dentry, inode);
 809                 dget(dentry);   /* Extra count - pin the dentry in core */
 810                 error = 0;
 811         }
 812         return error;
 813 }
 814
 815 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 816 {
 817         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 818         if (!retval)
 819                 inc_nlink(dir);
 820         return retval;
 821 }
 822
 823 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
 824 {
 825         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 826 }
 827
 828 static int hugetlbfs_symlink(struct inode *dir,
 829                         struct dentry *dentry, const char *symname)
 830 {
 831         struct inode *inode;
 832         int error = -ENOSPC;
 833
 834         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
 835         if (inode) {
 836                 int l = strlen(symname)+1;
 837                 error = page_symlink(inode, symname, l);
 838                 if (!error) {
 839                         d_instantiate(dentry, inode);
 840                         dget(dentry);
 841                 } else
 842                         iput(inode);
 843         }
 844         dir->i_ctime = dir->i_mtime = current_time(dir);
 845
 846         return error;
 847 }
 848
 849 /*
 850  * mark the head page dirty
 851  */
 852 static int hugetlbfs_set_page_dirty(struct page *page)
 853 {
 854         struct page *head = compound_head(page);
 855
 856         SetPageDirty(head);
 857         return 0;
 858 }
 859
 860 static int hugetlbfs_migrate_page(struct address_space *mapping,
 861                                 struct page *newpage, struct page *page,
 862                                 enum migrate_mode mode)
 863 {
 864         int rc;
 865
 866         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
 867         if (rc != MIGRATEPAGE_SUCCESS)
 868                 return rc;
 869
 870         /*
 871          * page_private is subpool pointer in hugetlb pages.  Transfer to
 872          * new page.  PagePrivate is not associated with page_private for
 873          * hugetlb pages and can not be set here as only page_huge_active
 874          * pages can be migrated.
 875          */
 876         if (page_private(page)) {
 877                 set_page_private(newpage, page_private(page));
 878                 set_page_private(page, 0);
 879         }
 880
 881         migrate_page_copy(newpage, page);
 882
 883         return MIGRATEPAGE_SUCCESS;
 884 }
 885
 886 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 887 {
 888         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
 889         struct hstate *h = hstate_inode(d_inode(dentry));
 890
 891         buf->f_type = HUGETLBFS_MAGIC;
 892         buf->f_bsize = huge_page_size(h);
 893         if (sbinfo) {
 894                 spin_lock(&sbinfo->stat_lock);
 895                 /* If no limits set, just report 0 for max/free/used
 896                  * blocks, like simple_statfs() */
 897                 if (sbinfo->spool) {
 898                         long free_pages;
 899
 900                         spin_lock(&sbinfo->spool->lock);
 901                         buf->f_blocks = sbinfo->spool->max_hpages;
 902                         free_pages = sbinfo->spool->max_hpages
 903                                 - sbinfo->spool->used_hpages;
 904                         buf->f_bavail = buf->f_bfree = free_pages;
 905                         spin_unlock(&sbinfo->spool->lock);
 906                         buf->f_files = sbinfo->max_inodes;
 907                         buf->f_ffree = sbinfo->free_inodes;
 908                 }
 909                 spin_unlock(&sbinfo->stat_lock);
 910         }
 911         buf->f_namelen = NAME_MAX;
 912         return 0;
 913 }
 914
 915 static void hugetlbfs_put_super(struct super_block *sb)
 916 {
 917         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 918
 919         if (sbi) {
 920                 sb->s_fs_info = NULL;
 921
 922                 if (sbi->spool)
 923                         hugepage_put_subpool(sbi->spool);
 924
 925                 kfree(sbi);
 926         }
 927 }
 928
 929 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 930 {
 931         if (sbinfo->free_inodes >= 0) {
 932                 spin_lock(&sbinfo->stat_lock);
 933                 if (unlikely(!sbinfo->free_inodes)) {
 934                         spin_unlock(&sbinfo->stat_lock);
 935                         return 0;
 936                 }
 937                 sbinfo->free_inodes--;
 938                 spin_unlock(&sbinfo->stat_lock);
 939         }
 940
 941         return 1;
 942 }
 943
 944 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 945 {
 946         if (sbinfo->free_inodes >= 0) {
 947                 spin_lock(&sbinfo->stat_lock);
 948                 sbinfo->free_inodes++;
 949                 spin_unlock(&sbinfo->stat_lock);
 950         }
 951 }
 952
 953
 954 static struct kmem_cache *hugetlbfs_inode_cachep;
 955
 956 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 957 {
 958         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 959         struct hugetlbfs_inode_info *p;
 960
 961         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 962                 return NULL;
 963         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
 964         if (unlikely(!p)) {
 965                 hugetlbfs_inc_free_inodes(sbinfo);
 966                 return NULL;
 967         }
 968
 969         /*
 970          * Any time after allocation, hugetlbfs_destroy_inode can be called
 971          * for the inode.  mpol_free_shared_policy is unconditionally called
 972          * as part of hugetlbfs_destroy_inode.  So, initialize policy here
 973          * in case of a quick call to destroy.
 974          *
 975          * Note that the policy is initialized even if we are creating a
 976          * private inode.  This simplifies hugetlbfs_destroy_inode.
 977          */
 978         mpol_shared_policy_init(&p->policy, NULL);
 979
 980         return &p->vfs_inode;
 981 }
 982
 983 static void hugetlbfs_i_callback(struct rcu_head *head)
 984 {
 985         struct inode *inode = container_of(head, struct inode, i_rcu);
 986         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 987 }
 988
 989 static void hugetlbfs_destroy_inode(struct inode *inode)
 990 {
 991         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 992         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 993         call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
 994 }
 995
 996 static const struct address_space_operations hugetlbfs_aops = {
 997         .write_begin    = hugetlbfs_write_begin,
 998         .write_end      = hugetlbfs_write_end,
 999         .set_page_dirty = hugetlbfs_set_page_dirty,
1000         .migratepage    = hugetlbfs_migrate_page,
1001 };
1002
1003
1004 static void init_once(void *foo)
1005 {
1006         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
1007
1008         inode_init_once(&ei->vfs_inode);
1009 }
1010
1011 const struct file_operations hugetlbfs_file_operations = {
1012         .read_iter              = hugetlbfs_read_iter,
1013         .mmap                   = hugetlbfs_file_mmap,
1014         .fsync                  = noop_fsync,
1015         .get_unmapped_area      = hugetlb_get_unmapped_area,
1016         .llseek                 = default_llseek,
1017         .fallocate              = hugetlbfs_fallocate,
1018 };
1019
1020 static const struct inode_operations hugetlbfs_dir_inode_operations = {
1021         .create         = hugetlbfs_create,
1022         .lookup         = simple_lookup,
1023         .link           = simple_link,
1024         .unlink         = simple_unlink,
1025         .symlink        = hugetlbfs_symlink,
1026         .mkdir          = hugetlbfs_mkdir,
1027         .rmdir          = simple_rmdir,
1028         .mknod          = hugetlbfs_mknod,
1029         .rename         = simple_rename,
1030         .setattr        = hugetlbfs_setattr,
1031 };
1032
1033 static const struct inode_operations hugetlbfs_inode_operations = {
1034         .setattr        = hugetlbfs_setattr,
1035 };
1036
1037 static const struct super_operations hugetlbfs_ops = {
1038         .alloc_inode    = hugetlbfs_alloc_inode,
1039         .destroy_inode  = hugetlbfs_destroy_inode,
1040         .evict_inode    = hugetlbfs_evict_inode,
1041         .statfs         = hugetlbfs_statfs,
1042         .put_super      = hugetlbfs_put_super,
1043         .show_options   = generic_show_options,
1044 };
1045
1046 enum { NO_SIZE, SIZE_STD, SIZE_PERCENT };
1047
1048 /*
1049  * Convert size option passed from command line to number of huge pages
1050  * in the pool specified by hstate.  Size option could be in bytes
1051  * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1052  */
1053 static long long
1054 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1055                                                                 int val_type)
1056 {
1057         if (val_type == NO_SIZE)
1058                 return -1;
1059
1060         if (val_type == SIZE_PERCENT) {
1061                 size_opt <<= huge_page_shift(h);
1062                 size_opt *= h->max_huge_pages;
1063                 do_div(size_opt, 100);
1064         }
1065
1066         size_opt >>= huge_page_shift(h);
1067         return size_opt;
1068 }
1069
1070 static int
1071 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
1072 {
1073         char *p, *rest;
1074         substring_t args[MAX_OPT_ARGS];
1075         int option;
1076         unsigned long long max_size_opt = 0, min_size_opt = 0;
1077         int max_val_type = NO_SIZE, min_val_type = NO_SIZE;
1078
1079         if (!options)
1080                 return 0;
1081
1082         while ((p = strsep(&options, ",")) != NULL) {
1083                 int token;
1084                 if (!*p)
1085                         continue;
1086
1087                 token = match_token(p, tokens, args);
1088                 switch (token) {
1089                 case Opt_uid:
1090                         if (match_int(&args[0], &option))
1091                                 goto bad_val;
1092                         pconfig->uid = make_kuid(current_user_ns(), option);
1093                         if (!uid_valid(pconfig->uid))
1094                                 goto bad_val;
1095                         break;
1096
1097                 case Opt_gid:
1098                         if (match_int(&args[0], &option))
1099                                 goto bad_val;
1100                         pconfig->gid = make_kgid(current_user_ns(), option);
1101                         if (!gid_valid(pconfig->gid))
1102                                 goto bad_val;
1103                         break;
1104
1105                 case Opt_mode:
1106                         if (match_octal(&args[0], &option))
1107                                 goto bad_val;
1108                         pconfig->mode = option & 01777U;
1109                         break;
1110
1111                 case Opt_size: {
1112                         /* memparse() will accept a K/M/G without a digit */
1113                         if (!isdigit(*args[0].from))
1114                                 goto bad_val;
1115                         max_size_opt = memparse(args[0].from, &rest);
1116                         max_val_type = SIZE_STD;
1117                         if (*rest == '%')
1118                                 max_val_type = SIZE_PERCENT;
1119                         break;
1120                 }
1121
1122                 case Opt_nr_inodes:
1123                         /* memparse() will accept a K/M/G without a digit */
1124                         if (!isdigit(*args[0].from))
1125                                 goto bad_val;
1126                         pconfig->nr_inodes = memparse(args[0].from, &rest);
1127                         break;
1128
1129                 case Opt_pagesize: {
1130                         unsigned long ps;
1131                         ps = memparse(args[0].from, &rest);
1132                         pconfig->hstate = size_to_hstate(ps);
1133                         if (!pconfig->hstate) {
1134                                 pr_err("Unsupported page size %lu MB\n",
1135                                         ps >> 20);
1136                                 return -EINVAL;
1137                         }
1138                         break;
1139                 }
1140
1141                 case Opt_min_size: {
1142                         /* memparse() will accept a K/M/G without a digit */
1143                         if (!isdigit(*args[0].from))
1144                                 goto bad_val;
1145                         min_size_opt = memparse(args[0].from, &rest);
1146                         min_val_type = SIZE_STD;
1147                         if (*rest == '%')
1148                                 min_val_type = SIZE_PERCENT;
1149                         break;
1150                 }
1151
1152                 default:
1153                         pr_err("Bad mount option: \"%s\"\n", p);
1154                         return -EINVAL;
1155                         break;
1156                 }
1157         }
1158
1159         /*
1160          * Use huge page pool size (in hstate) to convert the size
1161          * options to number of huge pages.  If NO_SIZE, -1 is returned.
1162          */
1163         pconfig->max_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
1164                                                 max_size_opt, max_val_type);
1165         pconfig->min_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
1166                                                 min_size_opt, min_val_type);
1167
1168         /*
1169          * If max_size was specified, then min_size must be smaller
1170          */
1171         if (max_val_type > NO_SIZE &&
1172             pconfig->min_hpages > pconfig->max_hpages) {
1173                 pr_err("minimum size can not be greater than maximum size\n");
1174                 return -EINVAL;
1175         }
1176
1177         return 0;
1178
1179 bad_val:
1180         pr_err("Bad value '%s' for mount option '%s'\n", args[0].from, p);
1181         return -EINVAL;
1182 }
1183
1184 static int
1185 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
1186 {
1187         int ret;
1188         struct hugetlbfs_config config;
1189         struct hugetlbfs_sb_info *sbinfo;
1190
1191         save_mount_options(sb, data);
1192
1193         config.max_hpages = -1; /* No limit on size by default */
1194         config.nr_inodes = -1; /* No limit on number of inodes by default */
1195         config.uid = current_fsuid();
1196         config.gid = current_fsgid();
1197         config.mode = 0755;
1198         config.hstate = &default_hstate;
1199         config.min_hpages = -1; /* No default minimum size */
1200         ret = hugetlbfs_parse_options(data, &config);
1201         if (ret)
1202                 return ret;
1203
1204         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1205         if (!sbinfo)
1206                 return -ENOMEM;
1207         sb->s_fs_info = sbinfo;
1208         sbinfo->hstate = config.hstate;
1209         spin_lock_init(&sbinfo->stat_lock);
1210         sbinfo->max_inodes = config.nr_inodes;
1211         sbinfo->free_inodes = config.nr_inodes;
1212         sbinfo->spool = NULL;
1213         /*
1214          * Allocate and initialize subpool if maximum or minimum size is
1215          * specified.  Any needed reservations (for minimim size) are taken
1216          * taken when the subpool is created.
1217          */
1218         if (config.max_hpages != -1 || config.min_hpages != -1) {
1219                 sbinfo->spool = hugepage_new_subpool(config.hstate,
1220                                                         config.max_hpages,
1221                                                         config.min_hpages);
1222                 if (!sbinfo->spool)
1223                         goto out_free;
1224         }
1225         sb->s_maxbytes = MAX_LFS_FILESIZE;
1226         sb->s_blocksize = huge_page_size(config.hstate);
1227         sb->s_blocksize_bits = huge_page_shift(config.hstate);
1228         sb->s_magic = HUGETLBFS_MAGIC;
1229         sb->s_op = &hugetlbfs_ops;
1230         sb->s_time_gran = 1;
1231         sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
1232         if (!sb->s_root)
1233                 goto out_free;
1234         return 0;
1235 out_free:
1236         kfree(sbinfo->spool);
1237         kfree(sbinfo);
1238         return -ENOMEM;
1239 }
1240
1241 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
1242         int flags, const char *dev_name, void *data)
1243 {
1244         return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
1245 }
1246
1247 static struct file_system_type hugetlbfs_fs_type = {
1248         .name           = "hugetlbfs",
1249         .mount          = hugetlbfs_mount,
1250         .kill_sb        = kill_litter_super,
1251 };
1252
1253 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1254
1255 static int can_do_hugetlb_shm(void)
1256 {
1257         kgid_t shm_group;
1258         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1259         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1260 }
1261
1262 static int get_hstate_idx(int page_size_log)
1263 {
1264         struct hstate *h = hstate_sizelog(page_size_log);
1265
1266         if (!h)
1267                 return -1;
1268         return h - hstates;
1269 }
1270
1271 static const struct dentry_operations anon_ops = {
1272         .d_dname = simple_dname
1273 };
1274
1275 /*
1276  * Note that size should be aligned to proper hugepage size in caller side,
1277  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1278  */
1279 struct file *hugetlb_file_setup(const char *name, size_t size,
1280                                 vm_flags_t acctflag, struct user_struct **user,
1281                                 int creat_flags, int page_size_log)
1282 {
1283         struct file *file = ERR_PTR(-ENOMEM);
1284         struct inode *inode;
1285         struct path path;
1286         struct super_block *sb;
1287         struct qstr quick_string;
1288         int hstate_idx;
1289
1290         hstate_idx = get_hstate_idx(page_size_log);
1291         if (hstate_idx < 0)
1292                 return ERR_PTR(-ENODEV);
1293
1294         *user = NULL;
1295         if (!hugetlbfs_vfsmount[hstate_idx])
1296                 return ERR_PTR(-ENOENT);
1297
1298         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1299                 *user = current_user();
1300                 if (user_shm_lock(size, *user)) {
1301                         task_lock(current);
1302                         pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
1303                                 current->comm, current->pid);
1304                         task_unlock(current);
1305                 } else {
1306                         *user = NULL;
1307                         return ERR_PTR(-EPERM);
1308                 }
1309         }
1310
1311         sb = hugetlbfs_vfsmount[hstate_idx]->mnt_sb;
1312         quick_string.name = name;
1313         quick_string.len = strlen(quick_string.name);
1314         quick_string.hash = 0;
1315         path.dentry = d_alloc_pseudo(sb, &quick_string);
1316         if (!path.dentry)
1317                 goto out_shm_unlock;
1318
1319         d_set_d_op(path.dentry, &anon_ops);
1320         path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]);
1321         file = ERR_PTR(-ENOSPC);
1322         inode = hugetlbfs_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0);
1323         if (!inode)
1324                 goto out_dentry;
1325         if (creat_flags == HUGETLB_SHMFS_INODE)
1326                 inode->i_flags |= S_PRIVATE;
1327
1328         file = ERR_PTR(-ENOMEM);
1329         if (hugetlb_reserve_pages(inode, 0,
1330                         size >> huge_page_shift(hstate_inode(inode)), NULL,
1331                         acctflag))
1332                 goto out_inode;
1333
1334         d_instantiate(path.dentry, inode);
1335         inode->i_size = size;
1336         clear_nlink(inode);
1337
1338         file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
1339                         &hugetlbfs_file_operations);
1340         if (IS_ERR(file))
1341                 goto out_dentry; /* inode is already attached */
1342
1343         return file;
1344
1345 out_inode:
1346         iput(inode);
1347 out_dentry:
1348         path_put(&path);
1349 out_shm_unlock:
1350         if (*user) {
1351                 user_shm_unlock(size, *user);
1352                 *user = NULL;
1353         }
1354         return file;
1355 }
1356
1357 static int __init init_hugetlbfs_fs(void)
1358 {
1359         struct hstate *h;
1360         int error;
1361         int i;
1362
1363         if (!hugepages_supported()) {
1364                 pr_info("disabling because there are no supported hugepage sizes\n");
1365                 return -ENOTSUPP;
1366         }
1367
1368         error = -ENOMEM;
1369         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1370                                         sizeof(struct hugetlbfs_inode_info),
1371                                         0, SLAB_ACCOUNT, init_once);
1372         if (hugetlbfs_inode_cachep == NULL)
1373                 goto out2;
1374
1375         error = register_filesystem(&hugetlbfs_fs_type);
1376         if (error)
1377                 goto out;
1378
1379         i = 0;
1380         for_each_hstate(h) {
1381                 char buf[50];
1382                 unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10);
1383
1384                 snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb);
1385                 hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type,
1386                                                         buf);
1387
1388                 if (IS_ERR(hugetlbfs_vfsmount[i])) {
1389                         pr_err("Cannot mount internal hugetlbfs for "
1390                                 "page size %uK", ps_kb);
1391                         error = PTR_ERR(hugetlbfs_vfsmount[i]);
1392                         hugetlbfs_vfsmount[i] = NULL;
1393                 }
1394                 i++;
1395         }
1396         /* Non default hstates are optional */
1397         if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx]))
1398                 return 0;
1399
1400  out:
1401         kmem_cache_destroy(hugetlbfs_inode_cachep);
1402  out2:
1403         return error;
1404 }
1405 fs_initcall(init_hugetlbfs_fs)