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