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/signal.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 <linux/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         struct hstate           *hstate;
  50         long                    max_hpages;
  51         long                    nr_inodes;
  52         long                    min_hpages;
  53         kuid_t                  uid;
  54         kgid_t                  gid;
  55         umode_t                 mode;
  56 };
  57
  58 int sysctl_hugetlb_shm_group;
  59
  60 enum {
  61         Opt_size, Opt_nr_inodes,
  62         Opt_mode, Opt_uid, Opt_gid,
  63         Opt_pagesize, Opt_min_size,
  64         Opt_err,
  65 };
  66
  67 static const match_table_t tokens = {
  68         {Opt_size,      "size=%s"},
  69         {Opt_nr_inodes, "nr_inodes=%s"},
  70         {Opt_mode,      "mode=%o"},
  71         {Opt_uid,       "uid=%u"},
  72         {Opt_gid,       "gid=%u"},
  73         {Opt_pagesize,  "pagesize=%s"},
  74         {Opt_min_size,  "min_size=%s"},
  75         {Opt_err,       NULL},
  76 };
  77
  78 #ifdef CONFIG_NUMA
  79 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
  80                                         struct inode *inode, pgoff_t index)
  81 {
  82         vma->vm_policy = mpol_shared_policy_lookup(&HUGETLBFS_I(inode)->policy,
  83                                                         index);
  84 }
  85
  86 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
  87 {
  88         mpol_cond_put(vma->vm_policy);
  89 }
  90 #else
  91 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
  92                                         struct inode *inode, pgoff_t index)
  93 {
  94 }
  95
  96 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
  97 {
  98 }
  99 #endif
 100
 101 static void huge_pagevec_release(struct pagevec *pvec)
 102 {
 103         int i;
 104
 105         for (i = 0; i < pagevec_count(pvec); ++i)
 106                 put_page(pvec->pages[i]);
 107
 108         pagevec_reinit(pvec);
 109 }
 110
 111 /*
 112  * Mask used when checking the page offset value passed in via system
 113  * calls.  This value will be converted to a loff_t which is signed.
 114  * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the
 115  * value.  The extra bit (- 1 in the shift value) is to take the sign
 116  * bit into account.
 117  */
 118 #define PGOFF_LOFFT_MAX \
 119         (((1UL << (PAGE_SHIFT + 1)) - 1) <<  (BITS_PER_LONG - (PAGE_SHIFT + 1)))
 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         /*
 140          * page based offset in vm_pgoff could be sufficiently large to
 141          * overflow a (l)off_t when converted to byte offset.
 142          */
 143         if (vma->vm_pgoff & PGOFF_LOFFT_MAX)
 144                 return -EINVAL;
 145
 146         /* must be huge page aligned */
 147         if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
 148                 return -EINVAL;
 149
 150         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
 151         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 152         /* check for overflow */
 153         if (len < vma_len)
 154                 return -EINVAL;
 155
 156         inode_lock(inode);
 157         file_accessed(file);
 158
 159         ret = -ENOMEM;
 160         if (hugetlb_reserve_pages(inode,
 161                                 vma->vm_pgoff >> huge_page_order(h),
 162                                 len >> huge_page_shift(h), vma,
 163                                 vma->vm_flags))
 164                 goto out;
 165
 166         ret = 0;
 167         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
 168                 i_size_write(inode, len);
 169 out:
 170         inode_unlock(inode);
 171
 172         return ret;
 173 }
 174
 175 /*
 176  * Called under down_write(mmap_sem).
 177  */
 178
 179 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 180 static unsigned long
 181 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 182                 unsigned long len, unsigned long pgoff, unsigned long flags)
 183 {
 184         struct mm_struct *mm = current->mm;
 185         struct vm_area_struct *vma;
 186         struct hstate *h = hstate_file(file);
 187         struct vm_unmapped_area_info info;
 188
 189         if (len & ~huge_page_mask(h))
 190                 return -EINVAL;
 191         if (len > TASK_SIZE)
 192                 return -ENOMEM;
 193
 194         if (flags & MAP_FIXED) {
 195                 if (prepare_hugepage_range(file, addr, len))
 196                         return -EINVAL;
 197                 return addr;
 198         }
 199
 200         if (addr) {
 201                 addr = ALIGN(addr, huge_page_size(h));
 202                 vma = find_vma(mm, addr);
 203                 if (TASK_SIZE - len >= addr &&
 204                     (!vma || addr + len <= vm_start_gap(vma)))
 205                         return addr;
 206         }
 207
 208         info.flags = 0;
 209         info.length = len;
 210         info.low_limit = TASK_UNMAPPED_BASE;
 211         info.high_limit = TASK_SIZE;
 212         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 213         info.align_offset = 0;
 214         return vm_unmapped_area(&info);
 215 }
 216 #endif
 217
 218 static size_t
 219 hugetlbfs_read_actor(struct page *page, unsigned long offset,
 220                         struct iov_iter *to, unsigned long size)
 221 {
 222         size_t copied = 0;
 223         int i, chunksize;
 224
 225         /* Find which 4k chunk and offset with in that chunk */
 226         i = offset >> PAGE_SHIFT;
 227         offset = offset & ~PAGE_MASK;
 228
 229         while (size) {
 230                 size_t n;
 231                 chunksize = PAGE_SIZE;
 232                 if (offset)
 233                         chunksize -= offset;
 234                 if (chunksize > size)
 235                         chunksize = size;
 236                 n = copy_page_to_iter(&page[i], offset, chunksize, to);
 237                 copied += n;
 238                 if (n != chunksize)
 239                         return copied;
 240                 offset = 0;
 241                 size -= chunksize;
 242                 i++;
 243         }
 244         return copied;
 245 }
 246
 247 /*
 248  * Support for read() - Find the page attached to f_mapping and copy out the
 249  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
 250  * since it has PAGE_SIZE assumptions.
 251  */
 252 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
 253 {
 254         struct file *file = iocb->ki_filp;
 255         struct hstate *h = hstate_file(file);
 256         struct address_space *mapping = file->f_mapping;
 257         struct inode *inode = mapping->host;
 258         unsigned long index = iocb->ki_pos >> huge_page_shift(h);
 259         unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
 260         unsigned long end_index;
 261         loff_t isize;
 262         ssize_t retval = 0;
 263
 264         while (iov_iter_count(to)) {
 265                 struct page *page;
 266                 size_t nr, copied;
 267
 268                 /* nr is the maximum number of bytes to copy from this page */
 269                 nr = huge_page_size(h);
 270                 isize = i_size_read(inode);
 271                 if (!isize)
 272                         break;
 273                 end_index = (isize - 1) >> huge_page_shift(h);
 274                 if (index > end_index)
 275                         break;
 276                 if (index == end_index) {
 277                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
 278                         if (nr <= offset)
 279                                 break;
 280                 }
 281                 nr = nr - offset;
 282
 283                 /* Find the page */
 284                 page = find_lock_page(mapping, index);
 285                 if (unlikely(page == NULL)) {
 286                         /*
 287                          * We have a HOLE, zero out the user-buffer for the
 288                          * length of the hole or request.
 289                          */
 290                         copied = iov_iter_zero(nr, to);
 291                 } else {
 292                         unlock_page(page);
 293
 294                         /*
 295                          * We have the page, copy it to user space buffer.
 296                          */
 297                         copied = hugetlbfs_read_actor(page, offset, to, nr);
 298                         put_page(page);
 299                 }
 300                 offset += copied;
 301                 retval += copied;
 302                 if (copied != nr && iov_iter_count(to)) {
 303                         if (!retval)
 304                                 retval = -EFAULT;
 305                         break;
 306                 }
 307                 index += offset >> huge_page_shift(h);
 308                 offset &= ~huge_page_mask(h);
 309         }
 310         iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
 311         return retval;
 312 }
 313
 314 static int hugetlbfs_write_begin(struct file *file,
 315                         struct address_space *mapping,
 316                         loff_t pos, unsigned len, unsigned flags,
 317                         struct page **pagep, void **fsdata)
 318 {
 319         return -EINVAL;
 320 }
 321
 322 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
 323                         loff_t pos, unsigned len, unsigned copied,
 324                         struct page *page, void *fsdata)
 325 {
 326         BUG();
 327         return -EINVAL;
 328 }
 329
 330 static void remove_huge_page(struct page *page)
 331 {
 332         ClearPageDirty(page);
 333         ClearPageUptodate(page);
 334         delete_from_page_cache(page);
 335 }
 336
 337 static void
 338 hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end)
 339 {
 340         struct vm_area_struct *vma;
 341
 342         /*
 343          * end == 0 indicates that the entire range after
 344          * start should be unmapped.
 345          */
 346         vma_interval_tree_foreach(vma, root, start, end ? end : ULONG_MAX) {
 347                 unsigned long v_offset;
 348                 unsigned long v_end;
 349
 350                 /*
 351                  * Can the expression below overflow on 32-bit arches?
 352                  * No, because the interval tree returns us only those vmas
 353                  * which overlap the truncated area starting at pgoff,
 354                  * and no vma on a 32-bit arch can span beyond the 4GB.
 355                  */
 356                 if (vma->vm_pgoff < start)
 357                         v_offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
 358                 else
 359                         v_offset = 0;
 360
 361                 if (!end)
 362                         v_end = vma->vm_end;
 363                 else {
 364                         v_end = ((end - vma->vm_pgoff) << PAGE_SHIFT)
 365                                                         + vma->vm_start;
 366                         if (v_end > vma->vm_end)
 367                                 v_end = vma->vm_end;
 368                 }
 369
 370                 unmap_hugepage_range(vma, vma->vm_start + v_offset, v_end,
 371                                                                         NULL);
 372         }
 373 }
 374
 375 /*
 376  * remove_inode_hugepages handles two distinct cases: truncation and hole
 377  * punch.  There are subtle differences in operation for each case.
 378  *
 379  * truncation is indicated by end of range being LLONG_MAX
 380  *      In this case, we first scan the range and release found pages.
 381  *      After releasing pages, hugetlb_unreserve_pages cleans up region/reserv
 382  *      maps and global counts.  Page faults can not race with truncation
 383  *      in this routine.  hugetlb_no_page() prevents page faults in the
 384  *      truncated range.  It checks i_size before allocation, and again after
 385  *      with the page table lock for the page held.  The same lock must be
 386  *      acquired to unmap a page.
 387  * hole punch is indicated if end is not LLONG_MAX
 388  *      In the hole punch case we scan the range and release found pages.
 389  *      Only when releasing a page is the associated region/reserv map
 390  *      deleted.  The region/reserv map for ranges without associated
 391  *      pages are not modified.  Page faults can race with hole punch.
 392  *      This is indicated if we find a mapped page.
 393  * Note: If the passed end of range value is beyond the end of file, but
 394  * not LLONG_MAX this routine still performs a hole punch operation.
 395  */
 396 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 397                                    loff_t lend)
 398 {
 399         struct hstate *h = hstate_inode(inode);
 400         struct address_space *mapping = &inode->i_data;
 401         const pgoff_t start = lstart >> huge_page_shift(h);
 402         const pgoff_t end = lend >> huge_page_shift(h);
 403         struct vm_area_struct pseudo_vma;
 404         struct pagevec pvec;
 405         pgoff_t next, index;
 406         int i, freed = 0;
 407         bool truncate_op = (lend == LLONG_MAX);
 408
 409         memset(&pseudo_vma, 0, sizeof(struct vm_area_struct));
 410         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
 411         pagevec_init(&pvec);
 412         next = start;
 413         while (next < end) {
 414                 /*
 415                  * When no more pages are found, we are done.
 416                  */
 417                 if (!pagevec_lookup_range(&pvec, mapping, &next, end - 1))
 418                         break;
 419
 420                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 421                         struct page *page = pvec.pages[i];
 422                         u32 hash;
 423
 424                         index = page->index;
 425                         hash = hugetlb_fault_mutex_hash(h, current->mm,
 426                                                         &pseudo_vma,
 427                                                         mapping, index, 0);
 428                         mutex_lock(&hugetlb_fault_mutex_table[hash]);
 429
 430                         /*
 431                          * If page is mapped, it was faulted in after being
 432                          * unmapped in caller.  Unmap (again) now after taking
 433                          * the fault mutex.  The mutex will prevent faults
 434                          * until we finish removing the page.
 435                          *
 436                          * This race can only happen in the hole punch case.
 437                          * Getting here in a truncate operation is a bug.
 438                          */
 439                         if (unlikely(page_mapped(page))) {
 440                                 BUG_ON(truncate_op);
 441
 442                                 i_mmap_lock_write(mapping);
 443                                 hugetlb_vmdelete_list(&mapping->i_mmap,
 444                                         index * pages_per_huge_page(h),
 445                                         (index + 1) * pages_per_huge_page(h));
 446                                 i_mmap_unlock_write(mapping);
 447                         }
 448
 449                         lock_page(page);
 450                         /*
 451                          * We must free the huge page and remove from page
 452                          * cache (remove_huge_page) BEFORE removing the
 453                          * region/reserve map (hugetlb_unreserve_pages).  In
 454                          * rare out of memory conditions, removal of the
 455                          * region/reserve map could fail. Correspondingly,
 456                          * the subpool and global reserve usage count can need
 457                          * to be adjusted.
 458                          */
 459                         VM_BUG_ON(PagePrivate(page));
 460                         remove_huge_page(page);
 461                         freed++;
 462                         if (!truncate_op) {
 463                                 if (unlikely(hugetlb_unreserve_pages(inode,
 464                                                         index, index + 1, 1)))
 465                                         hugetlb_fix_reserve_counts(inode);
 466                         }
 467
 468                         unlock_page(page);
 469                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 470                 }
 471                 huge_pagevec_release(&pvec);
 472                 cond_resched();
 473         }
 474
 475         if (truncate_op)
 476                 (void)hugetlb_unreserve_pages(inode, start, LONG_MAX, freed);
 477 }
 478
 479 static void hugetlbfs_evict_inode(struct inode *inode)
 480 {
 481         struct resv_map *resv_map;
 482
 483         remove_inode_hugepages(inode, 0, LLONG_MAX);
 484         resv_map = (struct resv_map *)inode->i_mapping->private_data;
 485         /* root inode doesn't have the resv_map, so we should check it */
 486         if (resv_map)
 487                 resv_map_release(&resv_map->refs);
 488         clear_inode(inode);
 489 }
 490
 491 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 492 {
 493         pgoff_t pgoff;
 494         struct address_space *mapping = inode->i_mapping;
 495         struct hstate *h = hstate_inode(inode);
 496
 497         BUG_ON(offset & ~huge_page_mask(h));
 498         pgoff = offset >> PAGE_SHIFT;
 499
 500         i_size_write(inode, offset);
 501         i_mmap_lock_write(mapping);
 502         if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
 503                 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0);
 504         i_mmap_unlock_write(mapping);
 505         remove_inode_hugepages(inode, offset, LLONG_MAX);
 506         return 0;
 507 }
 508
 509 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
 510 {
 511         struct hstate *h = hstate_inode(inode);
 512         loff_t hpage_size = huge_page_size(h);
 513         loff_t hole_start, hole_end;
 514
 515         /*
 516          * For hole punch round up the beginning offset of the hole and
 517          * round down the end.
 518          */
 519         hole_start = round_up(offset, hpage_size);
 520         hole_end = round_down(offset + len, hpage_size);
 521
 522         if (hole_end > hole_start) {
 523                 struct address_space *mapping = inode->i_mapping;
 524                 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 525
 526                 inode_lock(inode);
 527
 528                 /* protected by i_mutex */
 529                 if (info->seals & F_SEAL_WRITE) {
 530                         inode_unlock(inode);
 531                         return -EPERM;
 532                 }
 533
 534                 i_mmap_lock_write(mapping);
 535                 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
 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 hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 552         struct address_space *mapping = inode->i_mapping;
 553         struct hstate *h = hstate_inode(inode);
 554         struct vm_area_struct pseudo_vma;
 555         struct mm_struct *mm = current->mm;
 556         loff_t hpage_size = huge_page_size(h);
 557         unsigned long hpage_shift = huge_page_shift(h);
 558         pgoff_t start, index, end;
 559         int error;
 560         u32 hash;
 561
 562         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
 563                 return -EOPNOTSUPP;
 564
 565         if (mode & FALLOC_FL_PUNCH_HOLE)
 566                 return hugetlbfs_punch_hole(inode, offset, len);
 567
 568         /*
 569          * Default preallocate case.
 570          * For this range, start is rounded down and end is rounded up
 571          * as well as being converted to page offsets.
 572          */
 573         start = offset >> hpage_shift;
 574         end = (offset + len + hpage_size - 1) >> hpage_shift;
 575
 576         inode_lock(inode);
 577
 578         /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
 579         error = inode_newsize_ok(inode, offset + len);
 580         if (error)
 581                 goto out;
 582
 583         if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) {
 584                 error = -EPERM;
 585                 goto out;
 586         }
 587
 588         /*
 589          * Initialize a pseudo vma as this is required by the huge page
 590          * allocation routines.  If NUMA is configured, use page index
 591          * as input to create an allocation policy.
 592          */
 593         memset(&pseudo_vma, 0, sizeof(struct vm_area_struct));
 594         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
 595         pseudo_vma.vm_file = file;
 596
 597         for (index = start; index < end; index++) {
 598                 /*
 599                  * This is supposed to be the vaddr where the page is being
 600                  * faulted in, but we have no vaddr here.
 601                  */
 602                 struct page *page;
 603                 unsigned long addr;
 604                 int avoid_reserve = 0;
 605
 606                 cond_resched();
 607
 608                 /*
 609                  * fallocate(2) manpage permits EINTR; we may have been
 610                  * interrupted because we are using up too much memory.
 611                  */
 612                 if (signal_pending(current)) {
 613                         error = -EINTR;
 614                         break;
 615                 }
 616
 617                 /* Set numa allocation policy based on index */
 618                 hugetlb_set_vma_policy(&pseudo_vma, inode, index);
 619
 620                 /* addr is the offset within the file (zero based) */
 621                 addr = index * hpage_size;
 622
 623                 /* mutex taken here, fault path and hole punch */
 624                 hash = hugetlb_fault_mutex_hash(h, mm, &pseudo_vma, mapping,
 625                                                 index, addr);
 626                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
 627
 628                 /* See if already present in mapping to avoid alloc/free */
 629                 page = find_get_page(mapping, index);
 630                 if (page) {
 631                         put_page(page);
 632                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 633                         hugetlb_drop_vma_policy(&pseudo_vma);
 634                         continue;
 635                 }
 636
 637                 /* Allocate page and add to page cache */
 638                 page = alloc_huge_page(&pseudo_vma, addr, avoid_reserve);
 639                 hugetlb_drop_vma_policy(&pseudo_vma);
 640                 if (IS_ERR(page)) {
 641                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 642                         error = PTR_ERR(page);
 643                         goto out;
 644                 }
 645                 clear_huge_page(page, addr, pages_per_huge_page(h));
 646                 __SetPageUptodate(page);
 647                 error = huge_add_to_page_cache(page, mapping, index);
 648                 if (unlikely(error)) {
 649                         put_page(page);
 650                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 651                         goto out;
 652                 }
 653
 654                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 655
 656                 /*
 657                  * unlock_page because locked by add_to_page_cache()
 658                  * page_put due to reference from alloc_huge_page()
 659                  */
 660                 unlock_page(page);
 661                 put_page(page);
 662         }
 663
 664         if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
 665                 i_size_write(inode, offset + len);
 666         inode->i_ctime = current_time(inode);
 667 out:
 668         inode_unlock(inode);
 669         return error;
 670 }
 671
 672 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 673 {
 674         struct inode *inode = d_inode(dentry);
 675         struct hstate *h = hstate_inode(inode);
 676         int error;
 677         unsigned int ia_valid = attr->ia_valid;
 678         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 679
 680         BUG_ON(!inode);
 681
 682         error = setattr_prepare(dentry, attr);
 683         if (error)
 684                 return error;
 685
 686         if (ia_valid & ATTR_SIZE) {
 687                 loff_t oldsize = inode->i_size;
 688                 loff_t newsize = attr->ia_size;
 689
 690                 if (newsize & ~huge_page_mask(h))
 691                         return -EINVAL;
 692                 /* protected by i_mutex */
 693                 if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
 694                     (newsize > oldsize && (info->seals & F_SEAL_GROW)))
 695                         return -EPERM;
 696                 error = hugetlb_vmtruncate(inode, newsize);
 697                 if (error)
 698                         return error;
 699         }
 700
 701         setattr_copy(inode, attr);
 702         mark_inode_dirty(inode);
 703         return 0;
 704 }
 705
 706 static struct inode *hugetlbfs_get_root(struct super_block *sb,
 707                                         struct hugetlbfs_config *config)
 708 {
 709         struct inode *inode;
 710
 711         inode = new_inode(sb);
 712         if (inode) {
 713                 inode->i_ino = get_next_ino();
 714                 inode->i_mode = S_IFDIR | config->mode;
 715                 inode->i_uid = config->uid;
 716                 inode->i_gid = config->gid;
 717                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 718                 inode->i_op = &hugetlbfs_dir_inode_operations;
 719                 inode->i_fop = &simple_dir_operations;
 720                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
 721                 inc_nlink(inode);
 722                 lockdep_annotate_inode_mutex_key(inode);
 723         }
 724         return inode;
 725 }
 726
 727 /*
 728  * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
 729  * be taken from reclaim -- unlike regular filesystems. This needs an
 730  * annotation because huge_pmd_share() does an allocation under hugetlb's
 731  * i_mmap_rwsem.
 732  */
 733 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
 734
 735 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 736                                         struct inode *dir,
 737                                         umode_t mode, dev_t dev)
 738 {
 739         struct inode *inode;
 740         struct resv_map *resv_map;
 741
 742         resv_map = resv_map_alloc();
 743         if (!resv_map)
 744                 return NULL;
 745
 746         inode = new_inode(sb);
 747         if (inode) {
 748                 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 749
 750                 inode->i_ino = get_next_ino();
 751                 inode_init_owner(inode, dir, mode);
 752                 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
 753                                 &hugetlbfs_i_mmap_rwsem_key);
 754                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 755                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 756                 inode->i_mapping->private_data = resv_map;
 757                 info->seals = F_SEAL_SEAL;
 758                 switch (mode & S_IFMT) {
 759                 default:
 760                         init_special_inode(inode, mode, dev);
 761                         break;
 762                 case S_IFREG:
 763                         inode->i_op = &hugetlbfs_inode_operations;
 764                         inode->i_fop = &hugetlbfs_file_operations;
 765                         break;
 766                 case S_IFDIR:
 767                         inode->i_op = &hugetlbfs_dir_inode_operations;
 768                         inode->i_fop = &simple_dir_operations;
 769
 770                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 771                         inc_nlink(inode);
 772                         break;
 773                 case S_IFLNK:
 774                         inode->i_op = &page_symlink_inode_operations;
 775                         inode_nohighmem(inode);
 776                         break;
 777                 }
 778                 lockdep_annotate_inode_mutex_key(inode);
 779         } else
 780                 kref_put(&resv_map->refs, resv_map_release);
 781
 782         return inode;
 783 }
 784
 785 /*
 786  * File creation. Allocate an inode, and we're done..
 787  */
 788 static int hugetlbfs_mknod(struct inode *dir,
 789                         struct dentry *dentry, umode_t mode, dev_t dev)
 790 {
 791         struct inode *inode;
 792         int error = -ENOSPC;
 793
 794         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
 795         if (inode) {
 796                 dir->i_ctime = dir->i_mtime = current_time(dir);
 797                 d_instantiate(dentry, inode);
 798                 dget(dentry);   /* Extra count - pin the dentry in core */
 799                 error = 0;
 800         }
 801         return error;
 802 }
 803
 804 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 805 {
 806         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 807         if (!retval)
 808                 inc_nlink(dir);
 809         return retval;
 810 }
 811
 812 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
 813 {
 814         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 815 }
 816
 817 static int hugetlbfs_symlink(struct inode *dir,
 818                         struct dentry *dentry, const char *symname)
 819 {
 820         struct inode *inode;
 821         int error = -ENOSPC;
 822
 823         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
 824         if (inode) {
 825                 int l = strlen(symname)+1;
 826                 error = page_symlink(inode, symname, l);
 827                 if (!error) {
 828                         d_instantiate(dentry, inode);
 829                         dget(dentry);
 830                 } else
 831                         iput(inode);
 832         }
 833         dir->i_ctime = dir->i_mtime = current_time(dir);
 834
 835         return error;
 836 }
 837
 838 /*
 839  * mark the head page dirty
 840  */
 841 static int hugetlbfs_set_page_dirty(struct page *page)
 842 {
 843         struct page *head = compound_head(page);
 844
 845         SetPageDirty(head);
 846         return 0;
 847 }
 848
 849 static int hugetlbfs_migrate_page(struct address_space *mapping,
 850                                 struct page *newpage, struct page *page,
 851                                 enum migrate_mode mode)
 852 {
 853         int rc;
 854
 855         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
 856         if (rc != MIGRATEPAGE_SUCCESS)
 857                 return rc;
 858         if (mode != MIGRATE_SYNC_NO_COPY)
 859                 migrate_page_copy(newpage, page);
 860         else
 861                 migrate_page_states(newpage, page);
 862
 863         return MIGRATEPAGE_SUCCESS;
 864 }
 865
 866 static int hugetlbfs_error_remove_page(struct address_space *mapping,
 867                                 struct page *page)
 868 {
 869         struct inode *inode = mapping->host;
 870         pgoff_t index = page->index;
 871
 872         remove_huge_page(page);
 873         if (unlikely(hugetlb_unreserve_pages(inode, index, index + 1, 1)))
 874                 hugetlb_fix_reserve_counts(inode);
 875
 876         return 0;
 877 }
 878
 879 /*
 880  * Display the mount options in /proc/mounts.
 881  */
 882 static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root)
 883 {
 884         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(root->d_sb);
 885         struct hugepage_subpool *spool = sbinfo->spool;
 886         unsigned long hpage_size = huge_page_size(sbinfo->hstate);
 887         unsigned hpage_shift = huge_page_shift(sbinfo->hstate);
 888         char mod;
 889
 890         if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
 891                 seq_printf(m, ",uid=%u",
 892                            from_kuid_munged(&init_user_ns, sbinfo->uid));
 893         if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
 894                 seq_printf(m, ",gid=%u",
 895                            from_kgid_munged(&init_user_ns, sbinfo->gid));
 896         if (sbinfo->mode != 0755)
 897                 seq_printf(m, ",mode=%o", sbinfo->mode);
 898         if (sbinfo->max_inodes != -1)
 899                 seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes);
 900
 901         hpage_size /= 1024;
 902         mod = 'K';
 903         if (hpage_size >= 1024) {
 904                 hpage_size /= 1024;
 905                 mod = 'M';
 906         }
 907         seq_printf(m, ",pagesize=%lu%c", hpage_size, mod);
 908         if (spool) {
 909                 if (spool->max_hpages != -1)
 910                         seq_printf(m, ",size=%llu",
 911                                    (unsigned long long)spool->max_hpages << hpage_shift);
 912                 if (spool->min_hpages != -1)
 913                         seq_printf(m, ",min_size=%llu",
 914                                    (unsigned long long)spool->min_hpages << hpage_shift);
 915         }
 916         return 0;
 917 }
 918
 919 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 920 {
 921         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
 922         struct hstate *h = hstate_inode(d_inode(dentry));
 923
 924         buf->f_type = HUGETLBFS_MAGIC;
 925         buf->f_bsize = huge_page_size(h);
 926         if (sbinfo) {
 927                 spin_lock(&sbinfo->stat_lock);
 928                 /* If no limits set, just report 0 for max/free/used
 929                  * blocks, like simple_statfs() */
 930                 if (sbinfo->spool) {
 931                         long free_pages;
 932
 933                         spin_lock(&sbinfo->spool->lock);
 934                         buf->f_blocks = sbinfo->spool->max_hpages;
 935                         free_pages = sbinfo->spool->max_hpages
 936                                 - sbinfo->spool->used_hpages;
 937                         buf->f_bavail = buf->f_bfree = free_pages;
 938                         spin_unlock(&sbinfo->spool->lock);
 939                         buf->f_files = sbinfo->max_inodes;
 940                         buf->f_ffree = sbinfo->free_inodes;
 941                 }
 942                 spin_unlock(&sbinfo->stat_lock);
 943         }
 944         buf->f_namelen = NAME_MAX;
 945         return 0;
 946 }
 947
 948 static void hugetlbfs_put_super(struct super_block *sb)
 949 {
 950         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 951
 952         if (sbi) {
 953                 sb->s_fs_info = NULL;
 954
 955                 if (sbi->spool)
 956                         hugepage_put_subpool(sbi->spool);
 957
 958                 kfree(sbi);
 959         }
 960 }
 961
 962 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 963 {
 964         if (sbinfo->free_inodes >= 0) {
 965                 spin_lock(&sbinfo->stat_lock);
 966                 if (unlikely(!sbinfo->free_inodes)) {
 967                         spin_unlock(&sbinfo->stat_lock);
 968                         return 0;
 969                 }
 970                 sbinfo->free_inodes--;
 971                 spin_unlock(&sbinfo->stat_lock);
 972         }
 973
 974         return 1;
 975 }
 976
 977 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 978 {
 979         if (sbinfo->free_inodes >= 0) {
 980                 spin_lock(&sbinfo->stat_lock);
 981                 sbinfo->free_inodes++;
 982                 spin_unlock(&sbinfo->stat_lock);
 983         }
 984 }
 985
 986
 987 static struct kmem_cache *hugetlbfs_inode_cachep;
 988
 989 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 990 {
 991         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 992         struct hugetlbfs_inode_info *p;
 993
 994         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 995                 return NULL;
 996         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
 997         if (unlikely(!p)) {
 998                 hugetlbfs_inc_free_inodes(sbinfo);
 999                 return NULL;
1000         }
1001
1002         /*
1003          * Any time after allocation, hugetlbfs_destroy_inode can be called
1004          * for the inode.  mpol_free_shared_policy is unconditionally called
1005          * as part of hugetlbfs_destroy_inode.  So, initialize policy here
1006          * in case of a quick call to destroy.
1007          *
1008          * Note that the policy is initialized even if we are creating a
1009          * private inode.  This simplifies hugetlbfs_destroy_inode.
1010          */
1011         mpol_shared_policy_init(&p->policy, NULL);
1012
1013         return &p->vfs_inode;
1014 }
1015
1016 static void hugetlbfs_i_callback(struct rcu_head *head)
1017 {
1018         struct inode *inode = container_of(head, struct inode, i_rcu);
1019         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
1020 }
1021
1022 static void hugetlbfs_destroy_inode(struct inode *inode)
1023 {
1024         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
1025         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
1026         call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
1027 }
1028
1029 static const struct address_space_operations hugetlbfs_aops = {
1030         .write_begin    = hugetlbfs_write_begin,
1031         .write_end      = hugetlbfs_write_end,
1032         .set_page_dirty = hugetlbfs_set_page_dirty,
1033         .migratepage    = hugetlbfs_migrate_page,
1034         .error_remove_page      = hugetlbfs_error_remove_page,
1035 };
1036
1037
1038 static void init_once(void *foo)
1039 {
1040         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
1041
1042         inode_init_once(&ei->vfs_inode);
1043 }
1044
1045 const struct file_operations hugetlbfs_file_operations = {
1046         .read_iter              = hugetlbfs_read_iter,
1047         .mmap                   = hugetlbfs_file_mmap,
1048         .fsync                  = noop_fsync,
1049         .get_unmapped_area      = hugetlb_get_unmapped_area,
1050         .llseek                 = default_llseek,
1051         .fallocate              = hugetlbfs_fallocate,
1052 };
1053
1054 static const struct inode_operations hugetlbfs_dir_inode_operations = {
1055         .create         = hugetlbfs_create,
1056         .lookup         = simple_lookup,
1057         .link           = simple_link,
1058         .unlink         = simple_unlink,
1059         .symlink        = hugetlbfs_symlink,
1060         .mkdir          = hugetlbfs_mkdir,
1061         .rmdir          = simple_rmdir,
1062         .mknod          = hugetlbfs_mknod,
1063         .rename         = simple_rename,
1064         .setattr        = hugetlbfs_setattr,
1065 };
1066
1067 static const struct inode_operations hugetlbfs_inode_operations = {
1068         .setattr        = hugetlbfs_setattr,
1069 };
1070
1071 static const struct super_operations hugetlbfs_ops = {
1072         .alloc_inode    = hugetlbfs_alloc_inode,
1073         .destroy_inode  = hugetlbfs_destroy_inode,
1074         .evict_inode    = hugetlbfs_evict_inode,
1075         .statfs         = hugetlbfs_statfs,
1076         .put_super      = hugetlbfs_put_super,
1077         .show_options   = hugetlbfs_show_options,
1078 };
1079
1080 enum hugetlbfs_size_type { NO_SIZE, SIZE_STD, SIZE_PERCENT };
1081
1082 /*
1083  * Convert size option passed from command line to number of huge pages
1084  * in the pool specified by hstate.  Size option could be in bytes
1085  * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1086  */
1087 static long
1088 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1089                          enum hugetlbfs_size_type val_type)
1090 {
1091         if (val_type == NO_SIZE)
1092                 return -1;
1093
1094         if (val_type == SIZE_PERCENT) {
1095                 size_opt <<= huge_page_shift(h);
1096                 size_opt *= h->max_huge_pages;
1097                 do_div(size_opt, 100);
1098         }
1099
1100         size_opt >>= huge_page_shift(h);
1101         return size_opt;
1102 }
1103
1104 static int
1105 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
1106 {
1107         char *p, *rest;
1108         substring_t args[MAX_OPT_ARGS];
1109         int option;
1110         unsigned long long max_size_opt = 0, min_size_opt = 0;
1111         enum hugetlbfs_size_type max_val_type = NO_SIZE, min_val_type = NO_SIZE;
1112
1113         if (!options)
1114                 return 0;
1115
1116         while ((p = strsep(&options, ",")) != NULL) {
1117                 int token;
1118                 if (!*p)
1119                         continue;
1120
1121                 token = match_token(p, tokens, args);
1122                 switch (token) {
1123                 case Opt_uid:
1124                         if (match_int(&args[0], &option))
1125                                 goto bad_val;
1126                         pconfig->uid = make_kuid(current_user_ns(), option);
1127                         if (!uid_valid(pconfig->uid))
1128                                 goto bad_val;
1129                         break;
1130
1131                 case Opt_gid:
1132                         if (match_int(&args[0], &option))
1133                                 goto bad_val;
1134                         pconfig->gid = make_kgid(current_user_ns(), option);
1135                         if (!gid_valid(pconfig->gid))
1136                                 goto bad_val;
1137                         break;
1138
1139                 case Opt_mode:
1140                         if (match_octal(&args[0], &option))
1141                                 goto bad_val;
1142                         pconfig->mode = option & 01777U;
1143                         break;
1144
1145                 case Opt_size: {
1146                         /* memparse() will accept a K/M/G without a digit */
1147                         if (!isdigit(*args[0].from))
1148                                 goto bad_val;
1149                         max_size_opt = memparse(args[0].from, &rest);
1150                         max_val_type = SIZE_STD;
1151                         if (*rest == '%')
1152                                 max_val_type = SIZE_PERCENT;
1153                         break;
1154                 }
1155
1156                 case Opt_nr_inodes:
1157                         /* memparse() will accept a K/M/G without a digit */
1158                         if (!isdigit(*args[0].from))
1159                                 goto bad_val;
1160                         pconfig->nr_inodes = memparse(args[0].from, &rest);
1161                         break;
1162
1163                 case Opt_pagesize: {
1164                         unsigned long ps;
1165                         ps = memparse(args[0].from, &rest);
1166                         pconfig->hstate = size_to_hstate(ps);
1167                         if (!pconfig->hstate) {
1168                                 pr_err("Unsupported page size %lu MB\n",
1169                                         ps >> 20);
1170                                 return -EINVAL;
1171                         }
1172                         break;
1173                 }
1174
1175                 case Opt_min_size: {
1176                         /* memparse() will accept a K/M/G without a digit */
1177                         if (!isdigit(*args[0].from))
1178                                 goto bad_val;
1179                         min_size_opt = memparse(args[0].from, &rest);
1180                         min_val_type = SIZE_STD;
1181                         if (*rest == '%')
1182                                 min_val_type = SIZE_PERCENT;
1183                         break;
1184                 }
1185
1186                 default:
1187                         pr_err("Bad mount option: \"%s\"\n", p);
1188                         return -EINVAL;
1189                         break;
1190                 }
1191         }
1192
1193         /*
1194          * Use huge page pool size (in hstate) to convert the size
1195          * options to number of huge pages.  If NO_SIZE, -1 is returned.
1196          */
1197         pconfig->max_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
1198                                                 max_size_opt, max_val_type);
1199         pconfig->min_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
1200                                                 min_size_opt, min_val_type);
1201
1202         /*
1203          * If max_size was specified, then min_size must be smaller
1204          */
1205         if (max_val_type > NO_SIZE &&
1206             pconfig->min_hpages > pconfig->max_hpages) {
1207                 pr_err("minimum size can not be greater than maximum size\n");
1208                 return -EINVAL;
1209         }
1210
1211         return 0;
1212
1213 bad_val:
1214         pr_err("Bad value '%s' for mount option '%s'\n", args[0].from, p);
1215         return -EINVAL;
1216 }
1217
1218 static int
1219 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
1220 {
1221         int ret;
1222         struct hugetlbfs_config config;
1223         struct hugetlbfs_sb_info *sbinfo;
1224
1225         config.max_hpages = -1; /* No limit on size by default */
1226         config.nr_inodes = -1; /* No limit on number of inodes by default */
1227         config.uid = current_fsuid();
1228         config.gid = current_fsgid();
1229         config.mode = 0755;
1230         config.hstate = &default_hstate;
1231         config.min_hpages = -1; /* No default minimum size */
1232         ret = hugetlbfs_parse_options(data, &config);
1233         if (ret)
1234                 return ret;
1235
1236         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1237         if (!sbinfo)
1238                 return -ENOMEM;
1239         sb->s_fs_info = sbinfo;
1240         sbinfo->hstate = config.hstate;
1241         spin_lock_init(&sbinfo->stat_lock);
1242         sbinfo->max_inodes = config.nr_inodes;
1243         sbinfo->free_inodes = config.nr_inodes;
1244         sbinfo->spool = NULL;
1245         sbinfo->uid = config.uid;
1246         sbinfo->gid = config.gid;
1247         sbinfo->mode = config.mode;
1248
1249         /*
1250          * Allocate and initialize subpool if maximum or minimum size is
1251          * specified.  Any needed reservations (for minimim size) are taken
1252          * taken when the subpool is created.
1253          */
1254         if (config.max_hpages != -1 || config.min_hpages != -1) {
1255                 sbinfo->spool = hugepage_new_subpool(config.hstate,
1256                                                         config.max_hpages,
1257                                                         config.min_hpages);
1258                 if (!sbinfo->spool)
1259                         goto out_free;
1260         }
1261         sb->s_maxbytes = MAX_LFS_FILESIZE;
1262         sb->s_blocksize = huge_page_size(config.hstate);
1263         sb->s_blocksize_bits = huge_page_shift(config.hstate);
1264         sb->s_magic = HUGETLBFS_MAGIC;
1265         sb->s_op = &hugetlbfs_ops;
1266         sb->s_time_gran = 1;
1267         sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
1268         if (!sb->s_root)
1269                 goto out_free;
1270         return 0;
1271 out_free:
1272         kfree(sbinfo->spool);
1273         kfree(sbinfo);
1274         return -ENOMEM;
1275 }
1276
1277 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
1278         int flags, const char *dev_name, void *data)
1279 {
1280         return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
1281 }
1282
1283 static struct file_system_type hugetlbfs_fs_type = {
1284         .name           = "hugetlbfs",
1285         .mount          = hugetlbfs_mount,
1286         .kill_sb        = kill_litter_super,
1287 };
1288
1289 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1290
1291 static int can_do_hugetlb_shm(void)
1292 {
1293         kgid_t shm_group;
1294         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1295         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1296 }
1297
1298 static int get_hstate_idx(int page_size_log)
1299 {
1300         struct hstate *h = hstate_sizelog(page_size_log);
1301
1302         if (!h)
1303                 return -1;
1304         return h - hstates;
1305 }
1306
1307 static const struct dentry_operations anon_ops = {
1308         .d_dname = simple_dname
1309 };
1310
1311 /*
1312  * Note that size should be aligned to proper hugepage size in caller side,
1313  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1314  */
1315 struct file *hugetlb_file_setup(const char *name, size_t size,
1316                                 vm_flags_t acctflag, struct user_struct **user,
1317                                 int creat_flags, int page_size_log)
1318 {
1319         struct file *file = ERR_PTR(-ENOMEM);
1320         struct inode *inode;
1321         struct path path;
1322         struct super_block *sb;
1323         struct qstr quick_string;
1324         int hstate_idx;
1325
1326         hstate_idx = get_hstate_idx(page_size_log);
1327         if (hstate_idx < 0)
1328                 return ERR_PTR(-ENODEV);
1329
1330         *user = NULL;
1331         if (!hugetlbfs_vfsmount[hstate_idx])
1332                 return ERR_PTR(-ENOENT);
1333
1334         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1335                 *user = current_user();
1336                 if (user_shm_lock(size, *user)) {
1337                         task_lock(current);
1338                         pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
1339                                 current->comm, current->pid);
1340                         task_unlock(current);
1341                 } else {
1342                         *user = NULL;
1343                         return ERR_PTR(-EPERM);
1344                 }
1345         }
1346
1347         sb = hugetlbfs_vfsmount[hstate_idx]->mnt_sb;
1348         quick_string.name = name;
1349         quick_string.len = strlen(quick_string.name);
1350         quick_string.hash = 0;
1351         path.dentry = d_alloc_pseudo(sb, &quick_string);
1352         if (!path.dentry)
1353                 goto out_shm_unlock;
1354
1355         d_set_d_op(path.dentry, &anon_ops);
1356         path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]);
1357         file = ERR_PTR(-ENOSPC);
1358         inode = hugetlbfs_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0);
1359         if (!inode)
1360                 goto out_dentry;
1361         if (creat_flags == HUGETLB_SHMFS_INODE)
1362                 inode->i_flags |= S_PRIVATE;
1363
1364         file = ERR_PTR(-ENOMEM);
1365         if (hugetlb_reserve_pages(inode, 0,
1366                         size >> huge_page_shift(hstate_inode(inode)), NULL,
1367                         acctflag))
1368                 goto out_inode;
1369
1370         d_instantiate(path.dentry, inode);
1371         inode->i_size = size;
1372         clear_nlink(inode);
1373
1374         file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
1375                         &hugetlbfs_file_operations);
1376         if (IS_ERR(file))
1377                 goto out_dentry; /* inode is already attached */
1378
1379         return file;
1380
1381 out_inode:
1382         iput(inode);
1383 out_dentry:
1384         path_put(&path);
1385 out_shm_unlock:
1386         if (*user) {
1387                 user_shm_unlock(size, *user);
1388                 *user = NULL;
1389         }
1390         return file;
1391 }
1392
1393 static int __init init_hugetlbfs_fs(void)
1394 {
1395         struct hstate *h;
1396         int error;
1397         int i;
1398
1399         if (!hugepages_supported()) {
1400                 pr_info("disabling because there are no supported hugepage sizes\n");
1401                 return -ENOTSUPP;
1402         }
1403
1404         error = -ENOMEM;
1405         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1406                                         sizeof(struct hugetlbfs_inode_info),
1407                                         0, SLAB_ACCOUNT, init_once);
1408         if (hugetlbfs_inode_cachep == NULL)
1409                 goto out2;
1410
1411         error = register_filesystem(&hugetlbfs_fs_type);
1412         if (error)
1413                 goto out;
1414
1415         i = 0;
1416         for_each_hstate(h) {
1417                 char buf[50];
1418                 unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10);
1419
1420                 snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb);
1421                 hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type,
1422                                                         buf);
1423
1424                 if (IS_ERR(hugetlbfs_vfsmount[i])) {
1425                         pr_err("Cannot mount internal hugetlbfs for "
1426                                 "page size %uK", ps_kb);
1427                         error = PTR_ERR(hugetlbfs_vfsmount[i]);
1428                         hugetlbfs_vfsmount[i] = NULL;
1429                 }
1430                 i++;
1431         }
1432         /* Non default hstates are optional */
1433         if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx]))
1434                 return 0;
1435
1436  out:
1437         kmem_cache_destroy(hugetlbfs_inode_cachep);
1438  out2:
1439         return error;
1440 }
1441 fs_initcall(init_hugetlbfs_fs)