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