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/fs_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 #include <linux/sched/mm.h>
  42
  43 static const struct super_operations hugetlbfs_ops;
  44 static const struct address_space_operations hugetlbfs_aops;
  45 const struct file_operations hugetlbfs_file_operations;
  46 static const struct inode_operations hugetlbfs_dir_inode_operations;
  47 static const struct inode_operations hugetlbfs_inode_operations;
  48
  49 enum hugetlbfs_size_type { NO_SIZE, SIZE_STD, SIZE_PERCENT };
  50
  51 struct hugetlbfs_fs_context {
  52         struct hstate           *hstate;
  53         unsigned long long      max_size_opt;
  54         unsigned long long      min_size_opt;
  55         long                    max_hpages;
  56         long                    nr_inodes;
  57         long                    min_hpages;
  58         enum hugetlbfs_size_type max_val_type;
  59         enum hugetlbfs_size_type min_val_type;
  60         kuid_t                  uid;
  61         kgid_t                  gid;
  62         umode_t                 mode;
  63 };
  64
  65 int sysctl_hugetlb_shm_group;
  66
  67 enum hugetlb_param {
  68         Opt_gid,
  69         Opt_min_size,
  70         Opt_mode,
  71         Opt_nr_inodes,
  72         Opt_pagesize,
  73         Opt_size,
  74         Opt_uid,
  75 };
  76
  77 static const struct fs_parameter_spec hugetlb_fs_parameters[] = {
  78         fsparam_u32   ("gid",           Opt_gid),
  79         fsparam_string("min_size",      Opt_min_size),
  80         fsparam_u32oct("mode",          Opt_mode),
  81         fsparam_string("nr_inodes",     Opt_nr_inodes),
  82         fsparam_string("pagesize",      Opt_pagesize),
  83         fsparam_string("size",          Opt_size),
  84         fsparam_u32   ("uid",           Opt_uid),
  85         {}
  86 };
  87
  88 #ifdef CONFIG_NUMA
  89 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
  90                                         struct inode *inode, pgoff_t index)
  91 {
  92         vma->vm_policy = mpol_shared_policy_lookup(&HUGETLBFS_I(inode)->policy,
  93                                                         index);
  94 }
  95
  96 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
  97 {
  98         mpol_cond_put(vma->vm_policy);
  99 }
 100 #else
 101 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
 102                                         struct inode *inode, pgoff_t index)
 103 {
 104 }
 105
 106 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
 107 {
 108 }
 109 #endif
 110
 111 static void huge_pagevec_release(struct pagevec *pvec)
 112 {
 113         int i;
 114
 115         for (i = 0; i < pagevec_count(pvec); ++i)
 116                 put_page(pvec->pages[i]);
 117
 118         pagevec_reinit(pvec);
 119 }
 120
 121 /*
 122  * Mask used when checking the page offset value passed in via system
 123  * calls.  This value will be converted to a loff_t which is signed.
 124  * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the
 125  * value.  The extra bit (- 1 in the shift value) is to take the sign
 126  * bit into account.
 127  */
 128 #define PGOFF_LOFFT_MAX \
 129         (((1UL << (PAGE_SHIFT + 1)) - 1) <<  (BITS_PER_LONG - (PAGE_SHIFT + 1)))
 130
 131 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 132 {
 133         struct inode *inode = file_inode(file);
 134         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 135         loff_t len, vma_len;
 136         int ret;
 137         struct hstate *h = hstate_file(file);
 138         vm_flags_t vm_flags;
 139
 140         /*
 141          * vma address alignment (but not the pgoff alignment) has
 142          * already been checked by prepare_hugepage_range.  If you add
 143          * any error returns here, do so after setting VM_HUGETLB, so
 144          * is_vm_hugetlb_page tests below unmap_region go the right
 145          * way when do_mmap unwinds (may be important on powerpc
 146          * and ia64).
 147          */
 148         vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND;
 149         vma->vm_ops = &hugetlb_vm_ops;
 150
 151         ret = seal_check_future_write(info->seals, vma);
 152         if (ret)
 153                 return ret;
 154
 155         /*
 156          * page based offset in vm_pgoff could be sufficiently large to
 157          * overflow a loff_t when converted to byte offset.  This can
 158          * only happen on architectures where sizeof(loff_t) ==
 159          * sizeof(unsigned long).  So, only check in those instances.
 160          */
 161         if (sizeof(unsigned long) == sizeof(loff_t)) {
 162                 if (vma->vm_pgoff & PGOFF_LOFFT_MAX)
 163                         return -EINVAL;
 164         }
 165
 166         /* must be huge page aligned */
 167         if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
 168                 return -EINVAL;
 169
 170         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
 171         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 172         /* check for overflow */
 173         if (len < vma_len)
 174                 return -EINVAL;
 175
 176         inode_lock(inode);
 177         file_accessed(file);
 178
 179         ret = -ENOMEM;
 180
 181         vm_flags = vma->vm_flags;
 182         /*
 183          * for SHM_HUGETLB, the pages are reserved in the shmget() call so skip
 184          * reserving here. Note: only for SHM hugetlbfs file, the inode
 185          * flag S_PRIVATE is set.
 186          */
 187         if (inode->i_flags & S_PRIVATE)
 188                 vm_flags |= VM_NORESERVE;
 189
 190         if (!hugetlb_reserve_pages(inode,
 191                                 vma->vm_pgoff >> huge_page_order(h),
 192                                 len >> huge_page_shift(h), vma,
 193                                 vm_flags))
 194                 goto out;
 195
 196         ret = 0;
 197         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
 198                 i_size_write(inode, len);
 199 out:
 200         inode_unlock(inode);
 201
 202         return ret;
 203 }
 204
 205 /*
 206  * Called under mmap_write_lock(mm).
 207  */
 208
 209 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 210 static unsigned long
 211 hugetlb_get_unmapped_area_bottomup(struct file *file, unsigned long addr,
 212                 unsigned long len, unsigned long pgoff, unsigned long flags)
 213 {
 214         struct hstate *h = hstate_file(file);
 215         struct vm_unmapped_area_info info;
 216
 217         info.flags = 0;
 218         info.length = len;
 219         info.low_limit = current->mm->mmap_base;
 220         info.high_limit = arch_get_mmap_end(addr);
 221         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 222         info.align_offset = 0;
 223         return vm_unmapped_area(&info);
 224 }
 225
 226 static unsigned long
 227 hugetlb_get_unmapped_area_topdown(struct file *file, unsigned long addr,
 228                 unsigned long len, unsigned long pgoff, unsigned long flags)
 229 {
 230         struct hstate *h = hstate_file(file);
 231         struct vm_unmapped_area_info info;
 232
 233         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 234         info.length = len;
 235         info.low_limit = max(PAGE_SIZE, mmap_min_addr);
 236         info.high_limit = arch_get_mmap_base(addr, current->mm->mmap_base);
 237         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 238         info.align_offset = 0;
 239         addr = vm_unmapped_area(&info);
 240
 241         /*
 242          * A failed mmap() very likely causes application failure,
 243          * so fall back to the bottom-up function here. This scenario
 244          * can happen with large stack limits and large mmap()
 245          * allocations.
 246          */
 247         if (unlikely(offset_in_page(addr))) {
 248                 VM_BUG_ON(addr != -ENOMEM);
 249                 info.flags = 0;
 250                 info.low_limit = current->mm->mmap_base;
 251                 info.high_limit = arch_get_mmap_end(addr);
 252                 addr = vm_unmapped_area(&info);
 253         }
 254
 255         return addr;
 256 }
 257
 258 static unsigned long
 259 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 260                 unsigned long len, unsigned long pgoff, unsigned long flags)
 261 {
 262         struct mm_struct *mm = current->mm;
 263         struct vm_area_struct *vma;
 264         struct hstate *h = hstate_file(file);
 265         const unsigned long mmap_end = arch_get_mmap_end(addr);
 266
 267         if (len & ~huge_page_mask(h))
 268                 return -EINVAL;
 269         if (len > TASK_SIZE)
 270                 return -ENOMEM;
 271
 272         if (flags & MAP_FIXED) {
 273                 if (prepare_hugepage_range(file, addr, len))
 274                         return -EINVAL;
 275                 return addr;
 276         }
 277
 278         if (addr) {
 279                 addr = ALIGN(addr, huge_page_size(h));
 280                 vma = find_vma(mm, addr);
 281                 if (mmap_end - len >= addr &&
 282                     (!vma || addr + len <= vm_start_gap(vma)))
 283                         return addr;
 284         }
 285
 286         /*
 287          * Use mm->get_unmapped_area value as a hint to use topdown routine.
 288          * If architectures have special needs, they should define their own
 289          * version of hugetlb_get_unmapped_area.
 290          */
 291         if (mm->get_unmapped_area == arch_get_unmapped_area_topdown)
 292                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 293                                 pgoff, flags);
 294         return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 295                         pgoff, flags);
 296 }
 297 #endif
 298
 299 static size_t
 300 hugetlbfs_read_actor(struct page *page, unsigned long offset,
 301                         struct iov_iter *to, unsigned long size)
 302 {
 303         size_t copied = 0;
 304         int i, chunksize;
 305
 306         /* Find which 4k chunk and offset with in that chunk */
 307         i = offset >> PAGE_SHIFT;
 308         offset = offset & ~PAGE_MASK;
 309
 310         while (size) {
 311                 size_t n;
 312                 chunksize = PAGE_SIZE;
 313                 if (offset)
 314                         chunksize -= offset;
 315                 if (chunksize > size)
 316                         chunksize = size;
 317                 n = copy_page_to_iter(&page[i], offset, chunksize, to);
 318                 copied += n;
 319                 if (n != chunksize)
 320                         return copied;
 321                 offset = 0;
 322                 size -= chunksize;
 323                 i++;
 324         }
 325         return copied;
 326 }
 327
 328 /*
 329  * Support for read() - Find the page attached to f_mapping and copy out the
 330  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
 331  * since it has PAGE_SIZE assumptions.
 332  */
 333 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
 334 {
 335         struct file *file = iocb->ki_filp;
 336         struct hstate *h = hstate_file(file);
 337         struct address_space *mapping = file->f_mapping;
 338         struct inode *inode = mapping->host;
 339         unsigned long index = iocb->ki_pos >> huge_page_shift(h);
 340         unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
 341         unsigned long end_index;
 342         loff_t isize;
 343         ssize_t retval = 0;
 344
 345         while (iov_iter_count(to)) {
 346                 struct page *page;
 347                 size_t nr, copied;
 348
 349                 /* nr is the maximum number of bytes to copy from this page */
 350                 nr = huge_page_size(h);
 351                 isize = i_size_read(inode);
 352                 if (!isize)
 353                         break;
 354                 end_index = (isize - 1) >> huge_page_shift(h);
 355                 if (index > end_index)
 356                         break;
 357                 if (index == end_index) {
 358                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
 359                         if (nr <= offset)
 360                                 break;
 361                 }
 362                 nr = nr - offset;
 363
 364                 /* Find the page */
 365                 page = find_lock_page(mapping, index);
 366                 if (unlikely(page == NULL)) {
 367                         /*
 368                          * We have a HOLE, zero out the user-buffer for the
 369                          * length of the hole or request.
 370                          */
 371                         copied = iov_iter_zero(nr, to);
 372                 } else {
 373                         unlock_page(page);
 374
 375                         /*
 376                          * We have the page, copy it to user space buffer.
 377                          */
 378                         copied = hugetlbfs_read_actor(page, offset, to, nr);
 379                         put_page(page);
 380                 }
 381                 offset += copied;
 382                 retval += copied;
 383                 if (copied != nr && iov_iter_count(to)) {
 384                         if (!retval)
 385                                 retval = -EFAULT;
 386                         break;
 387                 }
 388                 index += offset >> huge_page_shift(h);
 389                 offset &= ~huge_page_mask(h);
 390         }
 391         iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
 392         return retval;
 393 }
 394
 395 static int hugetlbfs_write_begin(struct file *file,
 396                         struct address_space *mapping,
 397                         loff_t pos, unsigned len, unsigned flags,
 398                         struct page **pagep, void **fsdata)
 399 {
 400         return -EINVAL;
 401 }
 402
 403 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
 404                         loff_t pos, unsigned len, unsigned copied,
 405                         struct page *page, void *fsdata)
 406 {
 407         BUG();
 408         return -EINVAL;
 409 }
 410
 411 static void remove_huge_page(struct page *page)
 412 {
 413         ClearPageDirty(page);
 414         ClearPageUptodate(page);
 415         delete_from_page_cache(page);
 416 }
 417
 418 static void
 419 hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end)
 420 {
 421         struct vm_area_struct *vma;
 422
 423         /*
 424          * end == 0 indicates that the entire range after
 425          * start should be unmapped.
 426          */
 427         vma_interval_tree_foreach(vma, root, start, end ? end : ULONG_MAX) {
 428                 unsigned long v_offset;
 429                 unsigned long v_end;
 430
 431                 /*
 432                  * Can the expression below overflow on 32-bit arches?
 433                  * No, because the interval tree returns us only those vmas
 434                  * which overlap the truncated area starting at pgoff,
 435                  * and no vma on a 32-bit arch can span beyond the 4GB.
 436                  */
 437                 if (vma->vm_pgoff < start)
 438                         v_offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
 439                 else
 440                         v_offset = 0;
 441
 442                 if (!end)
 443                         v_end = vma->vm_end;
 444                 else {
 445                         v_end = ((end - vma->vm_pgoff) << PAGE_SHIFT)
 446                                                         + vma->vm_start;
 447                         if (v_end > vma->vm_end)
 448                                 v_end = vma->vm_end;
 449                 }
 450
 451                 unmap_hugepage_range(vma, vma->vm_start + v_offset, v_end,
 452                                                                         NULL);
 453         }
 454 }
 455
 456 /*
 457  * remove_inode_hugepages handles two distinct cases: truncation and hole
 458  * punch.  There are subtle differences in operation for each case.
 459  *
 460  * truncation is indicated by end of range being LLONG_MAX
 461  *      In this case, we first scan the range and release found pages.
 462  *      After releasing pages, hugetlb_unreserve_pages cleans up region/reserv
 463  *      maps and global counts.  Page faults can not race with truncation
 464  *      in this routine.  hugetlb_no_page() holds i_mmap_rwsem and prevents
 465  *      page faults in the truncated range by checking i_size.  i_size is
 466  *      modified while holding i_mmap_rwsem.
 467  * hole punch is indicated if end is not LLONG_MAX
 468  *      In the hole punch case we scan the range and release found pages.
 469  *      Only when releasing a page is the associated region/reserv map
 470  *      deleted.  The region/reserv map for ranges without associated
 471  *      pages are not modified.  Page faults can race with hole punch.
 472  *      This is indicated if we find a mapped page.
 473  * Note: If the passed end of range value is beyond the end of file, but
 474  * not LLONG_MAX this routine still performs a hole punch operation.
 475  */
 476 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 477                                    loff_t lend)
 478 {
 479         struct hstate *h = hstate_inode(inode);
 480         struct address_space *mapping = &inode->i_data;
 481         const pgoff_t start = lstart >> huge_page_shift(h);
 482         const pgoff_t end = lend >> huge_page_shift(h);
 483         struct vm_area_struct pseudo_vma;
 484         struct pagevec pvec;
 485         pgoff_t next, index;
 486         int i, freed = 0;
 487         bool truncate_op = (lend == LLONG_MAX);
 488
 489         vma_init(&pseudo_vma, current->mm);
 490         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
 491         pagevec_init(&pvec);
 492         next = start;
 493         while (next < end) {
 494                 /*
 495                  * When no more pages are found, we are done.
 496                  */
 497                 if (!pagevec_lookup_range(&pvec, mapping, &next, end - 1))
 498                         break;
 499
 500                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 501                         struct page *page = pvec.pages[i];
 502                         u32 hash;
 503
 504                         index = page->index;
 505                         hash = hugetlb_fault_mutex_hash(mapping, index);
 506                         if (!truncate_op) {
 507                                 /*
 508                                  * Only need to hold the fault mutex in the
 509                                  * hole punch case.  This prevents races with
 510                                  * page faults.  Races are not possible in the
 511                                  * case of truncation.
 512                                  */
 513                                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
 514                         }
 515
 516                         /*
 517                          * If page is mapped, it was faulted in after being
 518                          * unmapped in caller.  Unmap (again) now after taking
 519                          * the fault mutex.  The mutex will prevent faults
 520                          * until we finish removing the page.
 521                          *
 522                          * This race can only happen in the hole punch case.
 523                          * Getting here in a truncate operation is a bug.
 524                          */
 525                         if (unlikely(page_mapped(page))) {
 526                                 BUG_ON(truncate_op);
 527
 528                                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 529                                 i_mmap_lock_write(mapping);
 530                                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
 531                                 hugetlb_vmdelete_list(&mapping->i_mmap,
 532                                         index * pages_per_huge_page(h),
 533                                         (index + 1) * pages_per_huge_page(h));
 534                                 i_mmap_unlock_write(mapping);
 535                         }
 536
 537                         lock_page(page);
 538                         /*
 539                          * We must free the huge page and remove from page
 540                          * cache (remove_huge_page) BEFORE removing the
 541                          * region/reserve map (hugetlb_unreserve_pages).  In
 542                          * rare out of memory conditions, removal of the
 543                          * region/reserve map could fail. Correspondingly,
 544                          * the subpool and global reserve usage count can need
 545                          * to be adjusted.
 546                          */
 547                         VM_BUG_ON(PagePrivate(page));
 548                         remove_huge_page(page);
 549                         freed++;
 550                         if (!truncate_op) {
 551                                 if (unlikely(hugetlb_unreserve_pages(inode,
 552                                                         index, index + 1, 1)))
 553                                         hugetlb_fix_reserve_counts(inode);
 554                         }
 555
 556                         unlock_page(page);
 557                         if (!truncate_op)
 558                                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 559                 }
 560                 huge_pagevec_release(&pvec);
 561                 cond_resched();
 562         }
 563
 564         if (truncate_op)
 565                 (void)hugetlb_unreserve_pages(inode, start, LONG_MAX, freed);
 566 }
 567
 568 static void hugetlbfs_evict_inode(struct inode *inode)
 569 {
 570         struct resv_map *resv_map;
 571
 572         remove_inode_hugepages(inode, 0, LLONG_MAX);
 573
 574         /*
 575          * Get the resv_map from the address space embedded in the inode.
 576          * This is the address space which points to any resv_map allocated
 577          * at inode creation time.  If this is a device special inode,
 578          * i_mapping may not point to the original address space.
 579          */
 580         resv_map = (struct resv_map *)(&inode->i_data)->private_data;
 581         /* Only regular and link inodes have associated reserve maps */
 582         if (resv_map)
 583                 resv_map_release(&resv_map->refs);
 584         clear_inode(inode);
 585 }
 586
 587 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 588 {
 589         pgoff_t pgoff;
 590         struct address_space *mapping = inode->i_mapping;
 591         struct hstate *h = hstate_inode(inode);
 592
 593         BUG_ON(offset & ~huge_page_mask(h));
 594         pgoff = offset >> PAGE_SHIFT;
 595
 596         i_mmap_lock_write(mapping);
 597         i_size_write(inode, offset);
 598         if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
 599                 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0);
 600         i_mmap_unlock_write(mapping);
 601         remove_inode_hugepages(inode, offset, LLONG_MAX);
 602         return 0;
 603 }
 604
 605 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
 606 {
 607         struct hstate *h = hstate_inode(inode);
 608         loff_t hpage_size = huge_page_size(h);
 609         loff_t hole_start, hole_end;
 610
 611         /*
 612          * For hole punch round up the beginning offset of the hole and
 613          * round down the end.
 614          */
 615         hole_start = round_up(offset, hpage_size);
 616         hole_end = round_down(offset + len, hpage_size);
 617
 618         if (hole_end > hole_start) {
 619                 struct address_space *mapping = inode->i_mapping;
 620                 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 621
 622                 inode_lock(inode);
 623
 624                 /* protected by i_mutex */
 625                 if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) {
 626                         inode_unlock(inode);
 627                         return -EPERM;
 628                 }
 629
 630                 i_mmap_lock_write(mapping);
 631                 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
 632                         hugetlb_vmdelete_list(&mapping->i_mmap,
 633                                                 hole_start >> PAGE_SHIFT,
 634                                                 hole_end  >> PAGE_SHIFT);
 635                 i_mmap_unlock_write(mapping);
 636                 remove_inode_hugepages(inode, hole_start, hole_end);
 637                 inode_unlock(inode);
 638         }
 639
 640         return 0;
 641 }
 642
 643 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
 644                                 loff_t len)
 645 {
 646         struct inode *inode = file_inode(file);
 647         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 648         struct address_space *mapping = inode->i_mapping;
 649         struct hstate *h = hstate_inode(inode);
 650         struct vm_area_struct pseudo_vma;
 651         struct mm_struct *mm = current->mm;
 652         loff_t hpage_size = huge_page_size(h);
 653         unsigned long hpage_shift = huge_page_shift(h);
 654         pgoff_t start, index, end;
 655         int error;
 656         u32 hash;
 657
 658         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
 659                 return -EOPNOTSUPP;
 660
 661         if (mode & FALLOC_FL_PUNCH_HOLE)
 662                 return hugetlbfs_punch_hole(inode, offset, len);
 663
 664         /*
 665          * Default preallocate case.
 666          * For this range, start is rounded down and end is rounded up
 667          * as well as being converted to page offsets.
 668          */
 669         start = offset >> hpage_shift;
 670         end = (offset + len + hpage_size - 1) >> hpage_shift;
 671
 672         inode_lock(inode);
 673
 674         /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
 675         error = inode_newsize_ok(inode, offset + len);
 676         if (error)
 677                 goto out;
 678
 679         if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) {
 680                 error = -EPERM;
 681                 goto out;
 682         }
 683
 684         /*
 685          * Initialize a pseudo vma as this is required by the huge page
 686          * allocation routines.  If NUMA is configured, use page index
 687          * as input to create an allocation policy.
 688          */
 689         vma_init(&pseudo_vma, mm);
 690         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
 691         pseudo_vma.vm_file = file;
 692
 693         for (index = start; index < end; index++) {
 694                 /*
 695                  * This is supposed to be the vaddr where the page is being
 696                  * faulted in, but we have no vaddr here.
 697                  */
 698                 struct page *page;
 699                 unsigned long addr;
 700                 int avoid_reserve = 0;
 701
 702                 cond_resched();
 703
 704                 /*
 705                  * fallocate(2) manpage permits EINTR; we may have been
 706                  * interrupted because we are using up too much memory.
 707                  */
 708                 if (signal_pending(current)) {
 709                         error = -EINTR;
 710                         break;
 711                 }
 712
 713                 /* Set numa allocation policy based on index */
 714                 hugetlb_set_vma_policy(&pseudo_vma, inode, index);
 715
 716                 /* addr is the offset within the file (zero based) */
 717                 addr = index * hpage_size;
 718
 719                 /*
 720                  * fault mutex taken here, protects against fault path
 721                  * and hole punch.  inode_lock previously taken protects
 722                  * against truncation.
 723                  */
 724                 hash = hugetlb_fault_mutex_hash(mapping, index);
 725                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
 726
 727                 /* See if already present in mapping to avoid alloc/free */
 728                 page = find_get_page(mapping, index);
 729                 if (page) {
 730                         put_page(page);
 731                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 732                         hugetlb_drop_vma_policy(&pseudo_vma);
 733                         continue;
 734                 }
 735
 736                 /* Allocate page and add to page cache */
 737                 page = alloc_huge_page(&pseudo_vma, addr, avoid_reserve);
 738                 hugetlb_drop_vma_policy(&pseudo_vma);
 739                 if (IS_ERR(page)) {
 740                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 741                         error = PTR_ERR(page);
 742                         goto out;
 743                 }
 744                 clear_huge_page(page, addr, pages_per_huge_page(h));
 745                 __SetPageUptodate(page);
 746                 error = huge_add_to_page_cache(page, mapping, index);
 747                 if (unlikely(error)) {
 748                         put_page(page);
 749                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 750                         goto out;
 751                 }
 752
 753                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 754
 755                 set_page_huge_active(page);
 756                 /*
 757                  * unlock_page because locked by add_to_page_cache()
 758                  * put_page() due to reference from alloc_huge_page()
 759                  */
 760                 unlock_page(page);
 761                 put_page(page);
 762         }
 763
 764         if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
 765                 i_size_write(inode, offset + len);
 766         inode->i_ctime = current_time(inode);
 767 out:
 768         inode_unlock(inode);
 769         return error;
 770 }
 771
 772 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 773 {
 774         struct inode *inode = d_inode(dentry);
 775         struct hstate *h = hstate_inode(inode);
 776         int error;
 777         unsigned int ia_valid = attr->ia_valid;
 778         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 779
 780         BUG_ON(!inode);
 781
 782         error = setattr_prepare(dentry, attr);
 783         if (error)
 784                 return error;
 785
 786         if (ia_valid & ATTR_SIZE) {
 787                 loff_t oldsize = inode->i_size;
 788                 loff_t newsize = attr->ia_size;
 789
 790                 if (newsize & ~huge_page_mask(h))
 791                         return -EINVAL;
 792                 /* protected by i_mutex */
 793                 if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
 794                     (newsize > oldsize && (info->seals & F_SEAL_GROW)))
 795                         return -EPERM;
 796                 error = hugetlb_vmtruncate(inode, newsize);
 797                 if (error)
 798                         return error;
 799         }
 800
 801         setattr_copy(inode, attr);
 802         mark_inode_dirty(inode);
 803         return 0;
 804 }
 805
 806 static struct inode *hugetlbfs_get_root(struct super_block *sb,
 807                                         struct hugetlbfs_fs_context *ctx)
 808 {
 809         struct inode *inode;
 810
 811         inode = new_inode(sb);
 812         if (inode) {
 813                 inode->i_ino = get_next_ino();
 814                 inode->i_mode = S_IFDIR | ctx->mode;
 815                 inode->i_uid = ctx->uid;
 816                 inode->i_gid = ctx->gid;
 817                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 818                 inode->i_op = &hugetlbfs_dir_inode_operations;
 819                 inode->i_fop = &simple_dir_operations;
 820                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
 821                 inc_nlink(inode);
 822                 lockdep_annotate_inode_mutex_key(inode);
 823         }
 824         return inode;
 825 }
 826
 827 /*
 828  * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
 829  * be taken from reclaim -- unlike regular filesystems. This needs an
 830  * annotation because huge_pmd_share() does an allocation under hugetlb's
 831  * i_mmap_rwsem.
 832  */
 833 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
 834
 835 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 836                                         struct inode *dir,
 837                                         umode_t mode, dev_t dev)
 838 {
 839         struct inode *inode;
 840         struct resv_map *resv_map = NULL;
 841
 842         /*
 843          * Reserve maps are only needed for inodes that can have associated
 844          * page allocations.
 845          */
 846         if (S_ISREG(mode) || S_ISLNK(mode)) {
 847                 resv_map = resv_map_alloc();
 848                 if (!resv_map)
 849                         return NULL;
 850         }
 851
 852         inode = new_inode(sb);
 853         if (inode) {
 854                 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 855
 856                 inode->i_ino = get_next_ino();
 857                 inode_init_owner(inode, dir, mode);
 858                 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
 859                                 &hugetlbfs_i_mmap_rwsem_key);
 860                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 861                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 862                 inode->i_mapping->private_data = resv_map;
 863                 info->seals = F_SEAL_SEAL;
 864                 switch (mode & S_IFMT) {
 865                 default:
 866                         init_special_inode(inode, mode, dev);
 867                         break;
 868                 case S_IFREG:
 869                         inode->i_op = &hugetlbfs_inode_operations;
 870                         inode->i_fop = &hugetlbfs_file_operations;
 871                         break;
 872                 case S_IFDIR:
 873                         inode->i_op = &hugetlbfs_dir_inode_operations;
 874                         inode->i_fop = &simple_dir_operations;
 875
 876                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 877                         inc_nlink(inode);
 878                         break;
 879                 case S_IFLNK:
 880                         inode->i_op = &page_symlink_inode_operations;
 881                         inode_nohighmem(inode);
 882                         break;
 883                 }
 884                 lockdep_annotate_inode_mutex_key(inode);
 885         } else {
 886                 if (resv_map)
 887                         kref_put(&resv_map->refs, resv_map_release);
 888         }
 889
 890         return inode;
 891 }
 892
 893 /*
 894  * File creation. Allocate an inode, and we're done..
 895  */
 896 static int do_hugetlbfs_mknod(struct inode *dir,
 897                         struct dentry *dentry,
 898                         umode_t mode,
 899                         dev_t dev,
 900                         bool tmpfile)
 901 {
 902         struct inode *inode;
 903         int error = -ENOSPC;
 904
 905         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
 906         if (inode) {
 907                 dir->i_ctime = dir->i_mtime = current_time(dir);
 908                 if (tmpfile) {
 909                         d_tmpfile(dentry, inode);
 910                 } else {
 911                         d_instantiate(dentry, inode);
 912                         dget(dentry);/* Extra count - pin the dentry in core */
 913                 }
 914                 error = 0;
 915         }
 916         return error;
 917 }
 918
 919 static int hugetlbfs_mknod(struct inode *dir,
 920                         struct dentry *dentry, umode_t mode, dev_t dev)
 921 {
 922         return do_hugetlbfs_mknod(dir, dentry, mode, dev, false);
 923 }
 924
 925 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 926 {
 927         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 928         if (!retval)
 929                 inc_nlink(dir);
 930         return retval;
 931 }
 932
 933 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
 934 {
 935         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 936 }
 937
 938 static int hugetlbfs_tmpfile(struct inode *dir,
 939                         struct dentry *dentry, umode_t mode)
 940 {
 941         return do_hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0, true);
 942 }
 943
 944 static int hugetlbfs_symlink(struct inode *dir,
 945                         struct dentry *dentry, const char *symname)
 946 {
 947         struct inode *inode;
 948         int error = -ENOSPC;
 949
 950         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
 951         if (inode) {
 952                 int l = strlen(symname)+1;
 953                 error = page_symlink(inode, symname, l);
 954                 if (!error) {
 955                         d_instantiate(dentry, inode);
 956                         dget(dentry);
 957                 } else
 958                         iput(inode);
 959         }
 960         dir->i_ctime = dir->i_mtime = current_time(dir);
 961
 962         return error;
 963 }
 964
 965 /*
 966  * mark the head page dirty
 967  */
 968 static int hugetlbfs_set_page_dirty(struct page *page)
 969 {
 970         struct page *head = compound_head(page);
 971
 972         SetPageDirty(head);
 973         return 0;
 974 }
 975
 976 static int hugetlbfs_migrate_page(struct address_space *mapping,
 977                                 struct page *newpage, struct page *page,
 978                                 enum migrate_mode mode)
 979 {
 980         int rc;
 981
 982         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
 983         if (rc != MIGRATEPAGE_SUCCESS)
 984                 return rc;
 985
 986         /*
 987          * page_private is subpool pointer in hugetlb pages.  Transfer to
 988          * new page.  PagePrivate is not associated with page_private for
 989          * hugetlb pages and can not be set here as only page_huge_active
 990          * pages can be migrated.
 991          */
 992         if (page_private(page)) {
 993                 set_page_private(newpage, page_private(page));
 994                 set_page_private(page, 0);
 995         }
 996
 997         if (mode != MIGRATE_SYNC_NO_COPY)
 998                 migrate_page_copy(newpage, page);
 999         else
1000                 migrate_page_states(newpage, page);
1001
1002         return MIGRATEPAGE_SUCCESS;
1003 }
1004
1005 static int hugetlbfs_error_remove_page(struct address_space *mapping,
1006                                 struct page *page)
1007 {
1008         struct inode *inode = mapping->host;
1009         pgoff_t index = page->index;
1010
1011         remove_huge_page(page);
1012         if (unlikely(hugetlb_unreserve_pages(inode, index, index + 1, 1)))
1013                 hugetlb_fix_reserve_counts(inode);
1014
1015         return 0;
1016 }
1017
1018 /*
1019  * Display the mount options in /proc/mounts.
1020  */
1021 static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root)
1022 {
1023         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(root->d_sb);
1024         struct hugepage_subpool *spool = sbinfo->spool;
1025         unsigned long hpage_size = huge_page_size(sbinfo->hstate);
1026         unsigned hpage_shift = huge_page_shift(sbinfo->hstate);
1027         char mod;
1028
1029         if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
1030                 seq_printf(m, ",uid=%u",
1031                            from_kuid_munged(&init_user_ns, sbinfo->uid));
1032         if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
1033                 seq_printf(m, ",gid=%u",
1034                            from_kgid_munged(&init_user_ns, sbinfo->gid));
1035         if (sbinfo->mode != 0755)
1036                 seq_printf(m, ",mode=%o", sbinfo->mode);
1037         if (sbinfo->max_inodes != -1)
1038                 seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes);
1039
1040         hpage_size /= 1024;
1041         mod = 'K';
1042         if (hpage_size >= 1024) {
1043                 hpage_size /= 1024;
1044                 mod = 'M';
1045         }
1046         seq_printf(m, ",pagesize=%lu%c", hpage_size, mod);
1047         if (spool) {
1048                 if (spool->max_hpages != -1)
1049                         seq_printf(m, ",size=%llu",
1050                                    (unsigned long long)spool->max_hpages << hpage_shift);
1051                 if (spool->min_hpages != -1)
1052                         seq_printf(m, ",min_size=%llu",
1053                                    (unsigned long long)spool->min_hpages << hpage_shift);
1054         }
1055         return 0;
1056 }
1057
1058 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1059 {
1060         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
1061         struct hstate *h = hstate_inode(d_inode(dentry));
1062
1063         buf->f_type = HUGETLBFS_MAGIC;
1064         buf->f_bsize = huge_page_size(h);
1065         if (sbinfo) {
1066                 spin_lock(&sbinfo->stat_lock);
1067                 /* If no limits set, just report 0 for max/free/used
1068                  * blocks, like simple_statfs() */
1069                 if (sbinfo->spool) {
1070                         long free_pages;
1071
1072                         spin_lock(&sbinfo->spool->lock);
1073                         buf->f_blocks = sbinfo->spool->max_hpages;
1074                         free_pages = sbinfo->spool->max_hpages
1075                                 - sbinfo->spool->used_hpages;
1076                         buf->f_bavail = buf->f_bfree = free_pages;
1077                         spin_unlock(&sbinfo->spool->lock);
1078                         buf->f_files = sbinfo->max_inodes;
1079                         buf->f_ffree = sbinfo->free_inodes;
1080                 }
1081                 spin_unlock(&sbinfo->stat_lock);
1082         }
1083         buf->f_namelen = NAME_MAX;
1084         return 0;
1085 }
1086
1087 static void hugetlbfs_put_super(struct super_block *sb)
1088 {
1089         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
1090
1091         if (sbi) {
1092                 sb->s_fs_info = NULL;
1093
1094                 if (sbi->spool)
1095                         hugepage_put_subpool(sbi->spool);
1096
1097                 kfree(sbi);
1098         }
1099 }
1100
1101 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1102 {
1103         if (sbinfo->free_inodes >= 0) {
1104                 spin_lock(&sbinfo->stat_lock);
1105                 if (unlikely(!sbinfo->free_inodes)) {
1106                         spin_unlock(&sbinfo->stat_lock);
1107                         return 0;
1108                 }
1109                 sbinfo->free_inodes--;
1110                 spin_unlock(&sbinfo->stat_lock);
1111         }
1112
1113         return 1;
1114 }
1115
1116 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1117 {
1118         if (sbinfo->free_inodes >= 0) {
1119                 spin_lock(&sbinfo->stat_lock);
1120                 sbinfo->free_inodes++;
1121                 spin_unlock(&sbinfo->stat_lock);
1122         }
1123 }
1124
1125
1126 static struct kmem_cache *hugetlbfs_inode_cachep;
1127
1128 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
1129 {
1130         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
1131         struct hugetlbfs_inode_info *p;
1132
1133         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
1134                 return NULL;
1135         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
1136         if (unlikely(!p)) {
1137                 hugetlbfs_inc_free_inodes(sbinfo);
1138                 return NULL;
1139         }
1140
1141         /*
1142          * Any time after allocation, hugetlbfs_destroy_inode can be called
1143          * for the inode.  mpol_free_shared_policy is unconditionally called
1144          * as part of hugetlbfs_destroy_inode.  So, initialize policy here
1145          * in case of a quick call to destroy.
1146          *
1147          * Note that the policy is initialized even if we are creating a
1148          * private inode.  This simplifies hugetlbfs_destroy_inode.
1149          */
1150         mpol_shared_policy_init(&p->policy, NULL);
1151
1152         return &p->vfs_inode;
1153 }
1154
1155 static void hugetlbfs_free_inode(struct inode *inode)
1156 {
1157         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
1158 }
1159
1160 static void hugetlbfs_destroy_inode(struct inode *inode)
1161 {
1162         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
1163         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
1164 }
1165
1166 static const struct address_space_operations hugetlbfs_aops = {
1167         .write_begin    = hugetlbfs_write_begin,
1168         .write_end      = hugetlbfs_write_end,
1169         .set_page_dirty = hugetlbfs_set_page_dirty,
1170         .migratepage    = hugetlbfs_migrate_page,
1171         .error_remove_page      = hugetlbfs_error_remove_page,
1172 };
1173
1174
1175 static void init_once(void *foo)
1176 {
1177         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
1178
1179         inode_init_once(&ei->vfs_inode);
1180 }
1181
1182 const struct file_operations hugetlbfs_file_operations = {
1183         .read_iter              = hugetlbfs_read_iter,
1184         .mmap                   = hugetlbfs_file_mmap,
1185         .fsync                  = noop_fsync,
1186         .get_unmapped_area      = hugetlb_get_unmapped_area,
1187         .llseek                 = default_llseek,
1188         .fallocate              = hugetlbfs_fallocate,
1189 };
1190
1191 static const struct inode_operations hugetlbfs_dir_inode_operations = {
1192         .create         = hugetlbfs_create,
1193         .lookup         = simple_lookup,
1194         .link           = simple_link,
1195         .unlink         = simple_unlink,
1196         .symlink        = hugetlbfs_symlink,
1197         .mkdir          = hugetlbfs_mkdir,
1198         .rmdir          = simple_rmdir,
1199         .mknod          = hugetlbfs_mknod,
1200         .rename         = simple_rename,
1201         .setattr        = hugetlbfs_setattr,
1202         .tmpfile        = hugetlbfs_tmpfile,
1203 };
1204
1205 static const struct inode_operations hugetlbfs_inode_operations = {
1206         .setattr        = hugetlbfs_setattr,
1207 };
1208
1209 static const struct super_operations hugetlbfs_ops = {
1210         .alloc_inode    = hugetlbfs_alloc_inode,
1211         .free_inode     = hugetlbfs_free_inode,
1212         .destroy_inode  = hugetlbfs_destroy_inode,
1213         .evict_inode    = hugetlbfs_evict_inode,
1214         .statfs         = hugetlbfs_statfs,
1215         .put_super      = hugetlbfs_put_super,
1216         .show_options   = hugetlbfs_show_options,
1217 };
1218
1219 /*
1220  * Convert size option passed from command line to number of huge pages
1221  * in the pool specified by hstate.  Size option could be in bytes
1222  * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1223  */
1224 static long
1225 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1226                          enum hugetlbfs_size_type val_type)
1227 {
1228         if (val_type == NO_SIZE)
1229                 return -1;
1230
1231         if (val_type == SIZE_PERCENT) {
1232                 size_opt <<= huge_page_shift(h);
1233                 size_opt *= h->max_huge_pages;
1234                 do_div(size_opt, 100);
1235         }
1236
1237         size_opt >>= huge_page_shift(h);
1238         return size_opt;
1239 }
1240
1241 /*
1242  * Parse one mount parameter.
1243  */
1244 static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1245 {
1246         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1247         struct fs_parse_result result;
1248         struct hstate *h;
1249         char *rest;
1250         unsigned long ps;
1251         int opt;
1252
1253         opt = fs_parse(fc, hugetlb_fs_parameters, param, &result);
1254         if (opt < 0)
1255                 return opt;
1256
1257         switch (opt) {
1258         case Opt_uid:
1259                 ctx->uid = make_kuid(current_user_ns(), result.uint_32);
1260                 if (!uid_valid(ctx->uid))
1261                         goto bad_val;
1262                 return 0;
1263
1264         case Opt_gid:
1265                 ctx->gid = make_kgid(current_user_ns(), result.uint_32);
1266                 if (!gid_valid(ctx->gid))
1267                         goto bad_val;
1268                 return 0;
1269
1270         case Opt_mode:
1271                 ctx->mode = result.uint_32 & 01777U;
1272                 return 0;
1273
1274         case Opt_size:
1275                 /* memparse() will accept a K/M/G without a digit */
1276                 if (!param->string || !isdigit(param->string[0]))
1277                         goto bad_val;
1278                 ctx->max_size_opt = memparse(param->string, &rest);
1279                 ctx->max_val_type = SIZE_STD;
1280                 if (*rest == '%')
1281                         ctx->max_val_type = SIZE_PERCENT;
1282                 return 0;
1283
1284         case Opt_nr_inodes:
1285                 /* memparse() will accept a K/M/G without a digit */
1286                 if (!param->string || !isdigit(param->string[0]))
1287                         goto bad_val;
1288                 ctx->nr_inodes = memparse(param->string, &rest);
1289                 return 0;
1290
1291         case Opt_pagesize:
1292                 ps = memparse(param->string, &rest);
1293                 h = size_to_hstate(ps);
1294                 if (!h) {
1295                         pr_err("Unsupported page size %lu MB\n", ps >> 20);
1296                         return -EINVAL;
1297                 }
1298                 ctx->hstate = h;
1299                 return 0;
1300
1301         case Opt_min_size:
1302                 /* memparse() will accept a K/M/G without a digit */
1303                 if (!param->string || !isdigit(param->string[0]))
1304                         goto bad_val;
1305                 ctx->min_size_opt = memparse(param->string, &rest);
1306                 ctx->min_val_type = SIZE_STD;
1307                 if (*rest == '%')
1308                         ctx->min_val_type = SIZE_PERCENT;
1309                 return 0;
1310
1311         default:
1312                 return -EINVAL;
1313         }
1314
1315 bad_val:
1316         return invalfc(fc, "Bad value '%s' for mount option '%s'\n",
1317                       param->string, param->key);
1318 }
1319
1320 /*
1321  * Validate the parsed options.
1322  */
1323 static int hugetlbfs_validate(struct fs_context *fc)
1324 {
1325         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1326
1327         /*
1328          * Use huge page pool size (in hstate) to convert the size
1329          * options to number of huge pages.  If NO_SIZE, -1 is returned.
1330          */
1331         ctx->max_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1332                                                    ctx->max_size_opt,
1333                                                    ctx->max_val_type);
1334         ctx->min_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1335                                                    ctx->min_size_opt,
1336                                                    ctx->min_val_type);
1337
1338         /*
1339          * If max_size was specified, then min_size must be smaller
1340          */
1341         if (ctx->max_val_type > NO_SIZE &&
1342             ctx->min_hpages > ctx->max_hpages) {
1343                 pr_err("Minimum size can not be greater than maximum size\n");
1344                 return -EINVAL;
1345         }
1346
1347         return 0;
1348 }
1349
1350 static int
1351 hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc)
1352 {
1353         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1354         struct hugetlbfs_sb_info *sbinfo;
1355
1356         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1357         if (!sbinfo)
1358                 return -ENOMEM;
1359         sb->s_fs_info = sbinfo;
1360         spin_lock_init(&sbinfo->stat_lock);
1361         sbinfo->hstate          = ctx->hstate;
1362         sbinfo->max_inodes      = ctx->nr_inodes;
1363         sbinfo->free_inodes     = ctx->nr_inodes;
1364         sbinfo->spool           = NULL;
1365         sbinfo->uid             = ctx->uid;
1366         sbinfo->gid             = ctx->gid;
1367         sbinfo->mode            = ctx->mode;
1368
1369         /*
1370          * Allocate and initialize subpool if maximum or minimum size is
1371          * specified.  Any needed reservations (for minimim size) are taken
1372          * taken when the subpool is created.
1373          */
1374         if (ctx->max_hpages != -1 || ctx->min_hpages != -1) {
1375                 sbinfo->spool = hugepage_new_subpool(ctx->hstate,
1376                                                      ctx->max_hpages,
1377                                                      ctx->min_hpages);
1378                 if (!sbinfo->spool)
1379                         goto out_free;
1380         }
1381         sb->s_maxbytes = MAX_LFS_FILESIZE;
1382         sb->s_blocksize = huge_page_size(ctx->hstate);
1383         sb->s_blocksize_bits = huge_page_shift(ctx->hstate);
1384         sb->s_magic = HUGETLBFS_MAGIC;
1385         sb->s_op = &hugetlbfs_ops;
1386         sb->s_time_gran = 1;
1387
1388         /*
1389          * Due to the special and limited functionality of hugetlbfs, it does
1390          * not work well as a stacking filesystem.
1391          */
1392         sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
1393         sb->s_root = d_make_root(hugetlbfs_get_root(sb, ctx));
1394         if (!sb->s_root)
1395                 goto out_free;
1396         return 0;
1397 out_free:
1398         kfree(sbinfo->spool);
1399         kfree(sbinfo);
1400         return -ENOMEM;
1401 }
1402
1403 static int hugetlbfs_get_tree(struct fs_context *fc)
1404 {
1405         int err = hugetlbfs_validate(fc);
1406         if (err)
1407                 return err;
1408         return get_tree_nodev(fc, hugetlbfs_fill_super);
1409 }
1410
1411 static void hugetlbfs_fs_context_free(struct fs_context *fc)
1412 {
1413         kfree(fc->fs_private);
1414 }
1415
1416 static const struct fs_context_operations hugetlbfs_fs_context_ops = {
1417         .free           = hugetlbfs_fs_context_free,
1418         .parse_param    = hugetlbfs_parse_param,
1419         .get_tree       = hugetlbfs_get_tree,
1420 };
1421
1422 static int hugetlbfs_init_fs_context(struct fs_context *fc)
1423 {
1424         struct hugetlbfs_fs_context *ctx;
1425
1426         ctx = kzalloc(sizeof(struct hugetlbfs_fs_context), GFP_KERNEL);
1427         if (!ctx)
1428                 return -ENOMEM;
1429
1430         ctx->max_hpages = -1; /* No limit on size by default */
1431         ctx->nr_inodes  = -1; /* No limit on number of inodes by default */
1432         ctx->uid        = current_fsuid();
1433         ctx->gid        = current_fsgid();
1434         ctx->mode       = 0755;
1435         ctx->hstate     = &default_hstate;
1436         ctx->min_hpages = -1; /* No default minimum size */
1437         ctx->max_val_type = NO_SIZE;
1438         ctx->min_val_type = NO_SIZE;
1439         fc->fs_private = ctx;
1440         fc->ops = &hugetlbfs_fs_context_ops;
1441         return 0;
1442 }
1443
1444 static struct file_system_type hugetlbfs_fs_type = {
1445         .name                   = "hugetlbfs",
1446         .init_fs_context        = hugetlbfs_init_fs_context,
1447         .parameters             = hugetlb_fs_parameters,
1448         .kill_sb                = kill_litter_super,
1449 };
1450
1451 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1452
1453 static int can_do_hugetlb_shm(void)
1454 {
1455         kgid_t shm_group;
1456         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1457         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1458 }
1459
1460 static int get_hstate_idx(int page_size_log)
1461 {
1462         struct hstate *h = hstate_sizelog(page_size_log);
1463
1464         if (!h)
1465                 return -1;
1466         return h - hstates;
1467 }
1468
1469 /*
1470  * Note that size should be aligned to proper hugepage size in caller side,
1471  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1472  */
1473 struct file *hugetlb_file_setup(const char *name, size_t size,
1474                                 vm_flags_t acctflag, struct user_struct **user,
1475                                 int creat_flags, int page_size_log)
1476 {
1477         struct inode *inode;
1478         struct vfsmount *mnt;
1479         int hstate_idx;
1480         struct file *file;
1481
1482         hstate_idx = get_hstate_idx(page_size_log);
1483         if (hstate_idx < 0)
1484                 return ERR_PTR(-ENODEV);
1485
1486         *user = NULL;
1487         mnt = hugetlbfs_vfsmount[hstate_idx];
1488         if (!mnt)
1489                 return ERR_PTR(-ENOENT);
1490
1491         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1492                 *user = current_user();
1493                 if (user_shm_lock(size, *user)) {
1494                         task_lock(current);
1495                         pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
1496                                 current->comm, current->pid);
1497                         task_unlock(current);
1498                 } else {
1499                         *user = NULL;
1500                         return ERR_PTR(-EPERM);
1501                 }
1502         }
1503
1504         file = ERR_PTR(-ENOSPC);
1505         inode = hugetlbfs_get_inode(mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0);
1506         if (!inode)
1507                 goto out;
1508         if (creat_flags == HUGETLB_SHMFS_INODE)
1509                 inode->i_flags |= S_PRIVATE;
1510
1511         inode->i_size = size;
1512         clear_nlink(inode);
1513
1514         if (!hugetlb_reserve_pages(inode, 0,
1515                         size >> huge_page_shift(hstate_inode(inode)), NULL,
1516                         acctflag))
1517                 file = ERR_PTR(-ENOMEM);
1518         else
1519                 file = alloc_file_pseudo(inode, mnt, name, O_RDWR,
1520                                         &hugetlbfs_file_operations);
1521         if (!IS_ERR(file))
1522                 return file;
1523
1524         iput(inode);
1525 out:
1526         if (*user) {
1527                 user_shm_unlock(size, *user);
1528                 *user = NULL;
1529         }
1530         return file;
1531 }
1532
1533 static struct vfsmount *__init mount_one_hugetlbfs(struct hstate *h)
1534 {
1535         struct fs_context *fc;
1536         struct vfsmount *mnt;
1537
1538         fc = fs_context_for_mount(&hugetlbfs_fs_type, SB_KERNMOUNT);
1539         if (IS_ERR(fc)) {
1540                 mnt = ERR_CAST(fc);
1541         } else {
1542                 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1543                 ctx->hstate = h;
1544                 mnt = fc_mount(fc);
1545                 put_fs_context(fc);
1546         }
1547         if (IS_ERR(mnt))
1548                 pr_err("Cannot mount internal hugetlbfs for page size %uK",
1549                        1U << (h->order + PAGE_SHIFT - 10));
1550         return mnt;
1551 }
1552
1553 static int __init init_hugetlbfs_fs(void)
1554 {
1555         struct vfsmount *mnt;
1556         struct hstate *h;
1557         int error;
1558         int i;
1559
1560         if (!hugepages_supported()) {
1561                 pr_info("disabling because there are no supported hugepage sizes\n");
1562                 return -ENOTSUPP;
1563         }
1564
1565         error = -ENOMEM;
1566         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1567                                         sizeof(struct hugetlbfs_inode_info),
1568                                         0, SLAB_ACCOUNT, init_once);
1569         if (hugetlbfs_inode_cachep == NULL)
1570                 goto out;
1571
1572         error = register_filesystem(&hugetlbfs_fs_type);
1573         if (error)
1574                 goto out_free;
1575
1576         /* default hstate mount is required */
1577         mnt = mount_one_hugetlbfs(&hstates[default_hstate_idx]);
1578         if (IS_ERR(mnt)) {
1579                 error = PTR_ERR(mnt);
1580                 goto out_unreg;
1581         }
1582         hugetlbfs_vfsmount[default_hstate_idx] = mnt;
1583
1584         /* other hstates are optional */
1585         i = 0;
1586         for_each_hstate(h) {
1587                 if (i == default_hstate_idx) {
1588                         i++;
1589                         continue;
1590                 }
1591
1592                 mnt = mount_one_hugetlbfs(h);
1593                 if (IS_ERR(mnt))
1594                         hugetlbfs_vfsmount[i] = NULL;
1595                 else
1596                         hugetlbfs_vfsmount[i] = mnt;
1597                 i++;
1598         }
1599
1600         return 0;
1601
1602  out_unreg:
1603         (void)unregister_filesystem(&hugetlbfs_fs_type);
1604  out_free:
1605         kmem_cache_destroy(hugetlbfs_inode_cachep);
1606  out:
1607         return error;
1608 }
1609 fs_initcall(init_hugetlbfs_fs)