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 do_generic_mapping_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
 414          * start should be unmapped.
 415          */
 416         vma_interval_tree_foreach(vma, root, start, end ? end : ULONG_MAX) {
 417                 unsigned long v_offset;
 418                 unsigned long v_end;
 419
 420                 /*
 421                  * Can the expression below overflow on 32-bit arches?
 422                  * No, because the interval tree returns us only those vmas
 423                  * which overlap the truncated area starting at pgoff,
 424                  * and no vma on a 32-bit arch can span beyond the 4GB.
 425                  */
 426                 if (vma->vm_pgoff < start)
 427                         v_offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
 428                 else
 429                         v_offset = 0;
 430
 431                 if (!end)
 432                         v_end = vma->vm_end;
 433                 else {
 434                         v_end = ((end - vma->vm_pgoff) << PAGE_SHIFT)
 435                                                         + vma->vm_start;
 436                         if (v_end > vma->vm_end)
 437                                 v_end = vma->vm_end;
 438                 }
 439
 440                 unmap_hugepage_range(vma, vma->vm_start + v_offset, v_end,
 441                                                                         NULL);
 442         }
 443 }
 444
 445 /*
 446  * remove_inode_hugepages handles two distinct cases: truncation and hole
 447  * punch.  There are subtle differences in operation for each case.
 448  *
 449  * truncation is indicated by end of range being LLONG_MAX
 450  *      In this case, we first scan the range and release found pages.
 451  *      After releasing pages, hugetlb_unreserve_pages cleans up region/reserv
 452  *      maps and global counts.  Page faults can not race with truncation
 453  *      in this routine.  hugetlb_no_page() holds i_mmap_rwsem and prevents
 454  *      page faults in the truncated range by checking i_size.  i_size is
 455  *      modified while holding i_mmap_rwsem.
 456  * hole punch is indicated if end is not LLONG_MAX
 457  *      In the hole punch case we scan the range and release found pages.
 458  *      Only when releasing a page is the associated region/reserv map
 459  *      deleted.  The region/reserv map for ranges without associated
 460  *      pages are not modified.  Page faults can race with hole punch.
 461  *      This is indicated if we find a mapped page.
 462  * Note: If the passed end of range value is beyond the end of file, but
 463  * not LLONG_MAX this routine still performs a hole punch operation.
 464  */
 465 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 466                                    loff_t lend)
 467 {
 468         struct hstate *h = hstate_inode(inode);
 469         struct address_space *mapping = &inode->i_data;
 470         const pgoff_t start = lstart >> huge_page_shift(h);
 471         const pgoff_t end = lend >> huge_page_shift(h);
 472         struct vm_area_struct pseudo_vma;
 473         struct pagevec pvec;
 474         pgoff_t next, index;
 475         int i, freed = 0;
 476         bool truncate_op = (lend == LLONG_MAX);
 477
 478         vma_init(&pseudo_vma, current->mm);
 479         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
 480         pagevec_init(&pvec);
 481         next = start;
 482         while (next < end) {
 483                 /*
 484                  * When no more pages are found, we are done.
 485                  */
 486                 if (!pagevec_lookup_range(&pvec, mapping, &next, end - 1))
 487                         break;
 488
 489                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 490                         struct page *page = pvec.pages[i];
 491                         u32 hash;
 492
 493                         index = page->index;
 494                         hash = hugetlb_fault_mutex_hash(mapping, index);
 495                         if (!truncate_op) {
 496                                 /*
 497                                  * Only need to hold the fault mutex in the
 498                                  * hole punch case.  This prevents races with
 499                                  * page faults.  Races are not possible in the
 500                                  * case of truncation.
 501                                  */
 502                                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
 503                         }
 504
 505                         /*
 506                          * If page is mapped, it was faulted in after being
 507                          * unmapped in caller.  Unmap (again) now after taking
 508                          * the fault mutex.  The mutex will prevent faults
 509                          * until we finish removing the page.
 510                          *
 511                          * This race can only happen in the hole punch case.
 512                          * Getting here in a truncate operation is a bug.
 513                          */
 514                         if (unlikely(page_mapped(page))) {
 515                                 BUG_ON(truncate_op);
 516
 517                                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 518                                 i_mmap_lock_write(mapping);
 519                                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
 520                                 hugetlb_vmdelete_list(&mapping->i_mmap,
 521                                         index * pages_per_huge_page(h),
 522                                         (index + 1) * pages_per_huge_page(h));
 523                                 i_mmap_unlock_write(mapping);
 524                         }
 525
 526                         lock_page(page);
 527                         /*
 528                          * We must free the huge page and remove from page
 529                          * cache (remove_huge_page) BEFORE removing the
 530                          * region/reserve map (hugetlb_unreserve_pages).  In
 531                          * rare out of memory conditions, removal of the
 532                          * region/reserve map could fail. Correspondingly,
 533                          * the subpool and global reserve usage count can need
 534                          * to be adjusted.
 535                          */
 536                         VM_BUG_ON(PagePrivate(page));
 537                         remove_huge_page(page);
 538                         freed++;
 539                         if (!truncate_op) {
 540                                 if (unlikely(hugetlb_unreserve_pages(inode,
 541                                                         index, index + 1, 1)))
 542                                         hugetlb_fix_reserve_counts(inode);
 543                         }
 544
 545                         unlock_page(page);
 546                         if (!truncate_op)
 547                                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 548                 }
 549                 huge_pagevec_release(&pvec);
 550                 cond_resched();
 551         }
 552
 553         if (truncate_op)
 554                 (void)hugetlb_unreserve_pages(inode, start, LONG_MAX, freed);
 555 }
 556
 557 static void hugetlbfs_evict_inode(struct inode *inode)
 558 {
 559         struct resv_map *resv_map;
 560
 561         remove_inode_hugepages(inode, 0, LLONG_MAX);
 562
 563         /*
 564          * Get the resv_map from the address space embedded in the inode.
 565          * This is the address space which points to any resv_map allocated
 566          * at inode creation time.  If this is a device special inode,
 567          * i_mapping may not point to the original address space.
 568          */
 569         resv_map = (struct resv_map *)(&inode->i_data)->private_data;
 570         /* Only regular and link inodes have associated reserve maps */
 571         if (resv_map)
 572                 resv_map_release(&resv_map->refs);
 573         clear_inode(inode);
 574 }
 575
 576 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 577 {
 578         pgoff_t pgoff;
 579         struct address_space *mapping = inode->i_mapping;
 580         struct hstate *h = hstate_inode(inode);
 581
 582         BUG_ON(offset & ~huge_page_mask(h));
 583         pgoff = offset >> PAGE_SHIFT;
 584
 585         i_mmap_lock_write(mapping);
 586         i_size_write(inode, offset);
 587         if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
 588                 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0);
 589         i_mmap_unlock_write(mapping);
 590         remove_inode_hugepages(inode, offset, LLONG_MAX);
 591         return 0;
 592 }
 593
 594 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
 595 {
 596         struct hstate *h = hstate_inode(inode);
 597         loff_t hpage_size = huge_page_size(h);
 598         loff_t hole_start, hole_end;
 599
 600         /*
 601          * For hole punch round up the beginning offset of the hole and
 602          * round down the end.
 603          */
 604         hole_start = round_up(offset, hpage_size);
 605         hole_end = round_down(offset + len, hpage_size);
 606
 607         if (hole_end > hole_start) {
 608                 struct address_space *mapping = inode->i_mapping;
 609                 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 610
 611                 inode_lock(inode);
 612
 613                 /* protected by i_mutex */
 614                 if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) {
 615                         inode_unlock(inode);
 616                         return -EPERM;
 617                 }
 618
 619                 i_mmap_lock_write(mapping);
 620                 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
 621                         hugetlb_vmdelete_list(&mapping->i_mmap,
 622                                                 hole_start >> PAGE_SHIFT,
 623                                                 hole_end  >> PAGE_SHIFT);
 624                 i_mmap_unlock_write(mapping);
 625                 remove_inode_hugepages(inode, hole_start, hole_end);
 626                 inode_unlock(inode);
 627         }
 628
 629         return 0;
 630 }
 631
 632 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
 633                                 loff_t len)
 634 {
 635         struct inode *inode = file_inode(file);
 636         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 637         struct address_space *mapping = inode->i_mapping;
 638         struct hstate *h = hstate_inode(inode);
 639         struct vm_area_struct pseudo_vma;
 640         struct mm_struct *mm = current->mm;
 641         loff_t hpage_size = huge_page_size(h);
 642         unsigned long hpage_shift = huge_page_shift(h);
 643         pgoff_t start, index, end;
 644         int error;
 645         u32 hash;
 646
 647         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
 648                 return -EOPNOTSUPP;
 649
 650         if (mode & FALLOC_FL_PUNCH_HOLE)
 651                 return hugetlbfs_punch_hole(inode, offset, len);
 652
 653         /*
 654          * Default preallocate case.
 655          * For this range, start is rounded down and end is rounded up
 656          * as well as being converted to page offsets.
 657          */
 658         start = offset >> hpage_shift;
 659         end = (offset + len + hpage_size - 1) >> hpage_shift;
 660
 661         inode_lock(inode);
 662
 663         /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
 664         error = inode_newsize_ok(inode, offset + len);
 665         if (error)
 666                 goto out;
 667
 668         if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) {
 669                 error = -EPERM;
 670                 goto out;
 671         }
 672
 673         /*
 674          * Initialize a pseudo vma as this is required by the huge page
 675          * allocation routines.  If NUMA is configured, use page index
 676          * as input to create an allocation policy.
 677          */
 678         vma_init(&pseudo_vma, mm);
 679         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
 680         pseudo_vma.vm_file = file;
 681
 682         for (index = start; index < end; index++) {
 683                 /*
 684                  * This is supposed to be the vaddr where the page is being
 685                  * faulted in, but we have no vaddr here.
 686                  */
 687                 struct page *page;
 688                 unsigned long addr;
 689                 int avoid_reserve = 0;
 690
 691                 cond_resched();
 692
 693                 /*
 694                  * fallocate(2) manpage permits EINTR; we may have been
 695                  * interrupted because we are using up too much memory.
 696                  */
 697                 if (signal_pending(current)) {
 698                         error = -EINTR;
 699                         break;
 700                 }
 701
 702                 /* Set numa allocation policy based on index */
 703                 hugetlb_set_vma_policy(&pseudo_vma, inode, index);
 704
 705                 /* addr is the offset within the file (zero based) */
 706                 addr = index * hpage_size;
 707
 708                 /*
 709                  * fault mutex taken here, protects against fault path
 710                  * and hole punch.  inode_lock previously taken protects
 711                  * against truncation.
 712                  */
 713                 hash = hugetlb_fault_mutex_hash(mapping, index);
 714                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
 715
 716                 /* See if already present in mapping to avoid alloc/free */
 717                 page = find_get_page(mapping, index);
 718                 if (page) {
 719                         put_page(page);
 720                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 721                         hugetlb_drop_vma_policy(&pseudo_vma);
 722                         continue;
 723                 }
 724
 725                 /* Allocate page and add to page cache */
 726                 page = alloc_huge_page(&pseudo_vma, addr, avoid_reserve);
 727                 hugetlb_drop_vma_policy(&pseudo_vma);
 728                 if (IS_ERR(page)) {
 729                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 730                         error = PTR_ERR(page);
 731                         goto out;
 732                 }
 733                 clear_huge_page(page, addr, pages_per_huge_page(h));
 734                 __SetPageUptodate(page);
 735                 error = huge_add_to_page_cache(page, mapping, index);
 736                 if (unlikely(error)) {
 737                         put_page(page);
 738                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 739                         goto out;
 740                 }
 741
 742                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 743
 744                 set_page_huge_active(page);
 745                 /*
 746                  * unlock_page because locked by add_to_page_cache()
 747                  * put_page() due to reference from alloc_huge_page()
 748                  */
 749                 unlock_page(page);
 750                 put_page(page);
 751         }
 752
 753         if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
 754                 i_size_write(inode, offset + len);
 755         inode->i_ctime = current_time(inode);
 756 out:
 757         inode_unlock(inode);
 758         return error;
 759 }
 760
 761 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 762 {
 763         struct inode *inode = d_inode(dentry);
 764         struct hstate *h = hstate_inode(inode);
 765         int error;
 766         unsigned int ia_valid = attr->ia_valid;
 767         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 768
 769         BUG_ON(!inode);
 770
 771         error = setattr_prepare(dentry, attr);
 772         if (error)
 773                 return error;
 774
 775         if (ia_valid & ATTR_SIZE) {
 776                 loff_t oldsize = inode->i_size;
 777                 loff_t newsize = attr->ia_size;
 778
 779                 if (newsize & ~huge_page_mask(h))
 780                         return -EINVAL;
 781                 /* protected by i_mutex */
 782                 if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
 783                     (newsize > oldsize && (info->seals & F_SEAL_GROW)))
 784                         return -EPERM;
 785                 error = hugetlb_vmtruncate(inode, newsize);
 786                 if (error)
 787                         return error;
 788         }
 789
 790         setattr_copy(inode, attr);
 791         mark_inode_dirty(inode);
 792         return 0;
 793 }
 794
 795 static struct inode *hugetlbfs_get_root(struct super_block *sb,
 796                                         struct hugetlbfs_fs_context *ctx)
 797 {
 798         struct inode *inode;
 799
 800         inode = new_inode(sb);
 801         if (inode) {
 802                 inode->i_ino = get_next_ino();
 803                 inode->i_mode = S_IFDIR | ctx->mode;
 804                 inode->i_uid = ctx->uid;
 805                 inode->i_gid = ctx->gid;
 806                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 807                 inode->i_op = &hugetlbfs_dir_inode_operations;
 808                 inode->i_fop = &simple_dir_operations;
 809                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
 810                 inc_nlink(inode);
 811                 lockdep_annotate_inode_mutex_key(inode);
 812         }
 813         return inode;
 814 }
 815
 816 /*
 817  * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
 818  * be taken from reclaim -- unlike regular filesystems. This needs an
 819  * annotation because huge_pmd_share() does an allocation under hugetlb's
 820  * i_mmap_rwsem.
 821  */
 822 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
 823
 824 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 825                                         struct inode *dir,
 826                                         umode_t mode, dev_t dev)
 827 {
 828         struct inode *inode;
 829         struct resv_map *resv_map = NULL;
 830
 831         /*
 832          * Reserve maps are only needed for inodes that can have associated
 833          * page allocations.
 834          */
 835         if (S_ISREG(mode) || S_ISLNK(mode)) {
 836                 resv_map = resv_map_alloc();
 837                 if (!resv_map)
 838                         return NULL;
 839         }
 840
 841         inode = new_inode(sb);
 842         if (inode) {
 843                 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 844
 845                 inode->i_ino = get_next_ino();
 846                 inode_init_owner(inode, dir, mode);
 847                 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
 848                                 &hugetlbfs_i_mmap_rwsem_key);
 849                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 850                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 851                 inode->i_mapping->private_data = resv_map;
 852                 info->seals = F_SEAL_SEAL;
 853                 switch (mode & S_IFMT) {
 854                 default:
 855                         init_special_inode(inode, mode, dev);
 856                         break;
 857                 case S_IFREG:
 858                         inode->i_op = &hugetlbfs_inode_operations;
 859                         inode->i_fop = &hugetlbfs_file_operations;
 860                         break;
 861                 case S_IFDIR:
 862                         inode->i_op = &hugetlbfs_dir_inode_operations;
 863                         inode->i_fop = &simple_dir_operations;
 864
 865                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 866                         inc_nlink(inode);
 867                         break;
 868                 case S_IFLNK:
 869                         inode->i_op = &page_symlink_inode_operations;
 870                         inode_nohighmem(inode);
 871                         break;
 872                 }
 873                 lockdep_annotate_inode_mutex_key(inode);
 874         } else {
 875                 if (resv_map)
 876                         kref_put(&resv_map->refs, resv_map_release);
 877         }
 878
 879         return inode;
 880 }
 881
 882 /*
 883  * File creation. Allocate an inode, and we're done..
 884  */
 885 static int do_hugetlbfs_mknod(struct inode *dir,
 886                         struct dentry *dentry,
 887                         umode_t mode,
 888                         dev_t dev,
 889                         bool tmpfile)
 890 {
 891         struct inode *inode;
 892         int error = -ENOSPC;
 893
 894         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
 895         if (inode) {
 896                 dir->i_ctime = dir->i_mtime = current_time(dir);
 897                 if (tmpfile) {
 898                         d_tmpfile(dentry, inode);
 899                 } else {
 900                         d_instantiate(dentry, inode);
 901                         dget(dentry);/* Extra count - pin the dentry in core */
 902                 }
 903                 error = 0;
 904         }
 905         return error;
 906 }
 907
 908 static int hugetlbfs_mknod(struct inode *dir,
 909                         struct dentry *dentry, umode_t mode, dev_t dev)
 910 {
 911         return do_hugetlbfs_mknod(dir, dentry, mode, dev, false);
 912 }
 913
 914 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 915 {
 916         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 917         if (!retval)
 918                 inc_nlink(dir);
 919         return retval;
 920 }
 921
 922 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
 923 {
 924         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 925 }
 926
 927 static int hugetlbfs_tmpfile(struct inode *dir,
 928                         struct dentry *dentry, umode_t mode)
 929 {
 930         return do_hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0, true);
 931 }
 932
 933 static int hugetlbfs_symlink(struct inode *dir,
 934                         struct dentry *dentry, const char *symname)
 935 {
 936         struct inode *inode;
 937         int error = -ENOSPC;
 938
 939         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
 940         if (inode) {
 941                 int l = strlen(symname)+1;
 942                 error = page_symlink(inode, symname, l);
 943                 if (!error) {
 944                         d_instantiate(dentry, inode);
 945                         dget(dentry);
 946                 } else
 947                         iput(inode);
 948         }
 949         dir->i_ctime = dir->i_mtime = current_time(dir);
 950
 951         return error;
 952 }
 953
 954 /*
 955  * mark the head page dirty
 956  */
 957 static int hugetlbfs_set_page_dirty(struct page *page)
 958 {
 959         struct page *head = compound_head(page);
 960
 961         SetPageDirty(head);
 962         return 0;
 963 }
 964
 965 static int hugetlbfs_migrate_page(struct address_space *mapping,
 966                                 struct page *newpage, struct page *page,
 967                                 enum migrate_mode mode)
 968 {
 969         int rc;
 970
 971         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
 972         if (rc != MIGRATEPAGE_SUCCESS)
 973                 return rc;
 974
 975         /*
 976          * page_private is subpool pointer in hugetlb pages.  Transfer to
 977          * new page.  PagePrivate is not associated with page_private for
 978          * hugetlb pages and can not be set here as only page_huge_active
 979          * pages can be migrated.
 980          */
 981         if (page_private(page)) {
 982                 set_page_private(newpage, page_private(page));
 983                 set_page_private(page, 0);
 984         }
 985
 986         if (mode != MIGRATE_SYNC_NO_COPY)
 987                 migrate_page_copy(newpage, page);
 988         else
 989                 migrate_page_states(newpage, page);
 990
 991         return MIGRATEPAGE_SUCCESS;
 992 }
 993
 994 static int hugetlbfs_error_remove_page(struct address_space *mapping,
 995                                 struct page *page)
 996 {
 997         struct inode *inode = mapping->host;
 998         pgoff_t index = page->index;
 999
1000         remove_huge_page(page);
1001         if (unlikely(hugetlb_unreserve_pages(inode, index, index + 1, 1)))
1002                 hugetlb_fix_reserve_counts(inode);
1003
1004         return 0;
1005 }
1006
1007 /*
1008  * Display the mount options in /proc/mounts.
1009  */
1010 static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root)
1011 {
1012         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(root->d_sb);
1013         struct hugepage_subpool *spool = sbinfo->spool;
1014         unsigned long hpage_size = huge_page_size(sbinfo->hstate);
1015         unsigned hpage_shift = huge_page_shift(sbinfo->hstate);
1016         char mod;
1017
1018         if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
1019                 seq_printf(m, ",uid=%u",
1020                            from_kuid_munged(&init_user_ns, sbinfo->uid));
1021         if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
1022                 seq_printf(m, ",gid=%u",
1023                            from_kgid_munged(&init_user_ns, sbinfo->gid));
1024         if (sbinfo->mode != 0755)
1025                 seq_printf(m, ",mode=%o", sbinfo->mode);
1026         if (sbinfo->max_inodes != -1)
1027                 seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes);
1028
1029         hpage_size /= 1024;
1030         mod = 'K';
1031         if (hpage_size >= 1024) {
1032                 hpage_size /= 1024;
1033                 mod = 'M';
1034         }
1035         seq_printf(m, ",pagesize=%lu%c", hpage_size, mod);
1036         if (spool) {
1037                 if (spool->max_hpages != -1)
1038                         seq_printf(m, ",size=%llu",
1039                                    (unsigned long long)spool->max_hpages << hpage_shift);
1040                 if (spool->min_hpages != -1)
1041                         seq_printf(m, ",min_size=%llu",
1042                                    (unsigned long long)spool->min_hpages << hpage_shift);
1043         }
1044         return 0;
1045 }
1046
1047 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1048 {
1049         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
1050         struct hstate *h = hstate_inode(d_inode(dentry));
1051
1052         buf->f_type = HUGETLBFS_MAGIC;
1053         buf->f_bsize = huge_page_size(h);
1054         if (sbinfo) {
1055                 spin_lock(&sbinfo->stat_lock);
1056                 /* If no limits set, just report 0 for max/free/used
1057                  * blocks, like simple_statfs() */
1058                 if (sbinfo->spool) {
1059                         long free_pages;
1060
1061                         spin_lock(&sbinfo->spool->lock);
1062                         buf->f_blocks = sbinfo->spool->max_hpages;
1063                         free_pages = sbinfo->spool->max_hpages
1064                                 - sbinfo->spool->used_hpages;
1065                         buf->f_bavail = buf->f_bfree = free_pages;
1066                         spin_unlock(&sbinfo->spool->lock);
1067                         buf->f_files = sbinfo->max_inodes;
1068                         buf->f_ffree = sbinfo->free_inodes;
1069                 }
1070                 spin_unlock(&sbinfo->stat_lock);
1071         }
1072         buf->f_namelen = NAME_MAX;
1073         return 0;
1074 }
1075
1076 static void hugetlbfs_put_super(struct super_block *sb)
1077 {
1078         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
1079
1080         if (sbi) {
1081                 sb->s_fs_info = NULL;
1082
1083                 if (sbi->spool)
1084                         hugepage_put_subpool(sbi->spool);
1085
1086                 kfree(sbi);
1087         }
1088 }
1089
1090 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1091 {
1092         if (sbinfo->free_inodes >= 0) {
1093                 spin_lock(&sbinfo->stat_lock);
1094                 if (unlikely(!sbinfo->free_inodes)) {
1095                         spin_unlock(&sbinfo->stat_lock);
1096                         return 0;
1097                 }
1098                 sbinfo->free_inodes--;
1099                 spin_unlock(&sbinfo->stat_lock);
1100         }
1101
1102         return 1;
1103 }
1104
1105 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1106 {
1107         if (sbinfo->free_inodes >= 0) {
1108                 spin_lock(&sbinfo->stat_lock);
1109                 sbinfo->free_inodes++;
1110                 spin_unlock(&sbinfo->stat_lock);
1111         }
1112 }
1113
1114
1115 static struct kmem_cache *hugetlbfs_inode_cachep;
1116
1117 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
1118 {
1119         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
1120         struct hugetlbfs_inode_info *p;
1121
1122         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
1123                 return NULL;
1124         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
1125         if (unlikely(!p)) {
1126                 hugetlbfs_inc_free_inodes(sbinfo);
1127                 return NULL;
1128         }
1129
1130         /*
1131          * Any time after allocation, hugetlbfs_destroy_inode can be called
1132          * for the inode.  mpol_free_shared_policy is unconditionally called
1133          * as part of hugetlbfs_destroy_inode.  So, initialize policy here
1134          * in case of a quick call to destroy.
1135          *
1136          * Note that the policy is initialized even if we are creating a
1137          * private inode.  This simplifies hugetlbfs_destroy_inode.
1138          */
1139         mpol_shared_policy_init(&p->policy, NULL);
1140
1141         return &p->vfs_inode;
1142 }
1143
1144 static void hugetlbfs_free_inode(struct inode *inode)
1145 {
1146         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
1147 }
1148
1149 static void hugetlbfs_destroy_inode(struct inode *inode)
1150 {
1151         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
1152         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
1153 }
1154
1155 static const struct address_space_operations hugetlbfs_aops = {
1156         .write_begin    = hugetlbfs_write_begin,
1157         .write_end      = hugetlbfs_write_end,
1158         .set_page_dirty = hugetlbfs_set_page_dirty,
1159         .migratepage    = hugetlbfs_migrate_page,
1160         .error_remove_page      = hugetlbfs_error_remove_page,
1161 };
1162
1163
1164 static void init_once(void *foo)
1165 {
1166         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
1167
1168         inode_init_once(&ei->vfs_inode);
1169 }
1170
1171 const struct file_operations hugetlbfs_file_operations = {
1172         .read_iter              = hugetlbfs_read_iter,
1173         .mmap                   = hugetlbfs_file_mmap,
1174         .fsync                  = noop_fsync,
1175         .get_unmapped_area      = hugetlb_get_unmapped_area,
1176         .llseek                 = default_llseek,
1177         .fallocate              = hugetlbfs_fallocate,
1178 };
1179
1180 static const struct inode_operations hugetlbfs_dir_inode_operations = {
1181         .create         = hugetlbfs_create,
1182         .lookup         = simple_lookup,
1183         .link           = simple_link,
1184         .unlink         = simple_unlink,
1185         .symlink        = hugetlbfs_symlink,
1186         .mkdir          = hugetlbfs_mkdir,
1187         .rmdir          = simple_rmdir,
1188         .mknod          = hugetlbfs_mknod,
1189         .rename         = simple_rename,
1190         .setattr        = hugetlbfs_setattr,
1191         .tmpfile        = hugetlbfs_tmpfile,
1192 };
1193
1194 static const struct inode_operations hugetlbfs_inode_operations = {
1195         .setattr        = hugetlbfs_setattr,
1196 };
1197
1198 static const struct super_operations hugetlbfs_ops = {
1199         .alloc_inode    = hugetlbfs_alloc_inode,
1200         .free_inode     = hugetlbfs_free_inode,
1201         .destroy_inode  = hugetlbfs_destroy_inode,
1202         .evict_inode    = hugetlbfs_evict_inode,
1203         .statfs         = hugetlbfs_statfs,
1204         .put_super      = hugetlbfs_put_super,
1205         .show_options   = hugetlbfs_show_options,
1206 };
1207
1208 /*
1209  * Convert size option passed from command line to number of huge pages
1210  * in the pool specified by hstate.  Size option could be in bytes
1211  * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1212  */
1213 static long
1214 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1215                          enum hugetlbfs_size_type val_type)
1216 {
1217         if (val_type == NO_SIZE)
1218                 return -1;
1219
1220         if (val_type == SIZE_PERCENT) {
1221                 size_opt <<= huge_page_shift(h);
1222                 size_opt *= h->max_huge_pages;
1223                 do_div(size_opt, 100);
1224         }
1225
1226         size_opt >>= huge_page_shift(h);
1227         return size_opt;
1228 }
1229
1230 /*
1231  * Parse one mount parameter.
1232  */
1233 static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1234 {
1235         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1236         struct fs_parse_result result;
1237         char *rest;
1238         unsigned long ps;
1239         int opt;
1240
1241         opt = fs_parse(fc, hugetlb_fs_parameters, param, &result);
1242         if (opt < 0)
1243                 return opt;
1244
1245         switch (opt) {
1246         case Opt_uid:
1247                 ctx->uid = make_kuid(current_user_ns(), result.uint_32);
1248                 if (!uid_valid(ctx->uid))
1249                         goto bad_val;
1250                 return 0;
1251
1252         case Opt_gid:
1253                 ctx->gid = make_kgid(current_user_ns(), result.uint_32);
1254                 if (!gid_valid(ctx->gid))
1255                         goto bad_val;
1256                 return 0;
1257
1258         case Opt_mode:
1259                 ctx->mode = result.uint_32 & 01777U;
1260                 return 0;
1261
1262         case Opt_size:
1263                 /* memparse() will accept a K/M/G without a digit */
1264                 if (!isdigit(param->string[0]))
1265                         goto bad_val;
1266                 ctx->max_size_opt = memparse(param->string, &rest);
1267                 ctx->max_val_type = SIZE_STD;
1268                 if (*rest == '%')
1269                         ctx->max_val_type = SIZE_PERCENT;
1270                 return 0;
1271
1272         case Opt_nr_inodes:
1273                 /* memparse() will accept a K/M/G without a digit */
1274                 if (!isdigit(param->string[0]))
1275                         goto bad_val;
1276                 ctx->nr_inodes = memparse(param->string, &rest);
1277                 return 0;
1278
1279         case Opt_pagesize:
1280                 ps = memparse(param->string, &rest);
1281                 ctx->hstate = size_to_hstate(ps);
1282                 if (!ctx->hstate) {
1283                         pr_err("Unsupported page size %lu MB\n", ps >> 20);
1284                         return -EINVAL;
1285                 }
1286                 return 0;
1287
1288         case Opt_min_size:
1289                 /* memparse() will accept a K/M/G without a digit */
1290                 if (!isdigit(param->string[0]))
1291                         goto bad_val;
1292                 ctx->min_size_opt = memparse(param->string, &rest);
1293                 ctx->min_val_type = SIZE_STD;
1294                 if (*rest == '%')
1295                         ctx->min_val_type = SIZE_PERCENT;
1296                 return 0;
1297
1298         default:
1299                 return -EINVAL;
1300         }
1301
1302 bad_val:
1303         return invalfc(fc, "Bad value '%s' for mount option '%s'\n",
1304                       param->string, param->key);
1305 }
1306
1307 /*
1308  * Validate the parsed options.
1309  */
1310 static int hugetlbfs_validate(struct fs_context *fc)
1311 {
1312         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1313
1314         /*
1315          * Use huge page pool size (in hstate) to convert the size
1316          * options to number of huge pages.  If NO_SIZE, -1 is returned.
1317          */
1318         ctx->max_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1319                                                    ctx->max_size_opt,
1320                                                    ctx->max_val_type);
1321         ctx->min_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1322                                                    ctx->min_size_opt,
1323                                                    ctx->min_val_type);
1324
1325         /*
1326          * If max_size was specified, then min_size must be smaller
1327          */
1328         if (ctx->max_val_type > NO_SIZE &&
1329             ctx->min_hpages > ctx->max_hpages) {
1330                 pr_err("Minimum size can not be greater than maximum size\n");
1331                 return -EINVAL;
1332         }
1333
1334         return 0;
1335 }
1336
1337 static int
1338 hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc)
1339 {
1340         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1341         struct hugetlbfs_sb_info *sbinfo;
1342
1343         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1344         if (!sbinfo)
1345                 return -ENOMEM;
1346         sb->s_fs_info = sbinfo;
1347         spin_lock_init(&sbinfo->stat_lock);
1348         sbinfo->hstate          = ctx->hstate;
1349         sbinfo->max_inodes      = ctx->nr_inodes;
1350         sbinfo->free_inodes     = ctx->nr_inodes;
1351         sbinfo->spool           = NULL;
1352         sbinfo->uid             = ctx->uid;
1353         sbinfo->gid             = ctx->gid;
1354         sbinfo->mode            = ctx->mode;
1355
1356         /*
1357          * Allocate and initialize subpool if maximum or minimum size is
1358          * specified.  Any needed reservations (for minimim size) are taken
1359          * taken when the subpool is created.
1360          */
1361         if (ctx->max_hpages != -1 || ctx->min_hpages != -1) {
1362                 sbinfo->spool = hugepage_new_subpool(ctx->hstate,
1363                                                      ctx->max_hpages,
1364                                                      ctx->min_hpages);
1365                 if (!sbinfo->spool)
1366                         goto out_free;
1367         }
1368         sb->s_maxbytes = MAX_LFS_FILESIZE;
1369         sb->s_blocksize = huge_page_size(ctx->hstate);
1370         sb->s_blocksize_bits = huge_page_shift(ctx->hstate);
1371         sb->s_magic = HUGETLBFS_MAGIC;
1372         sb->s_op = &hugetlbfs_ops;
1373         sb->s_time_gran = 1;
1374
1375         /*
1376          * Due to the special and limited functionality of hugetlbfs, it does
1377          * not work well as a stacking filesystem.
1378          */
1379         sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
1380         sb->s_root = d_make_root(hugetlbfs_get_root(sb, ctx));
1381         if (!sb->s_root)
1382                 goto out_free;
1383         return 0;
1384 out_free:
1385         kfree(sbinfo->spool);
1386         kfree(sbinfo);
1387         return -ENOMEM;
1388 }
1389
1390 static int hugetlbfs_get_tree(struct fs_context *fc)
1391 {
1392         int err = hugetlbfs_validate(fc);
1393         if (err)
1394                 return err;
1395         return get_tree_nodev(fc, hugetlbfs_fill_super);
1396 }
1397
1398 static void hugetlbfs_fs_context_free(struct fs_context *fc)
1399 {
1400         kfree(fc->fs_private);
1401 }
1402
1403 static const struct fs_context_operations hugetlbfs_fs_context_ops = {
1404         .free           = hugetlbfs_fs_context_free,
1405         .parse_param    = hugetlbfs_parse_param,
1406         .get_tree       = hugetlbfs_get_tree,
1407 };
1408
1409 static int hugetlbfs_init_fs_context(struct fs_context *fc)
1410 {
1411         struct hugetlbfs_fs_context *ctx;
1412
1413         ctx = kzalloc(sizeof(struct hugetlbfs_fs_context), GFP_KERNEL);
1414         if (!ctx)
1415                 return -ENOMEM;
1416
1417         ctx->max_hpages = -1; /* No limit on size by default */
1418         ctx->nr_inodes  = -1; /* No limit on number of inodes by default */
1419         ctx->uid        = current_fsuid();
1420         ctx->gid        = current_fsgid();
1421         ctx->mode       = 0755;
1422         ctx->hstate     = &default_hstate;
1423         ctx->min_hpages = -1; /* No default minimum size */
1424         ctx->max_val_type = NO_SIZE;
1425         ctx->min_val_type = NO_SIZE;
1426         fc->fs_private = ctx;
1427         fc->ops = &hugetlbfs_fs_context_ops;
1428         return 0;
1429 }
1430
1431 static struct file_system_type hugetlbfs_fs_type = {
1432         .name                   = "hugetlbfs",
1433         .init_fs_context        = hugetlbfs_init_fs_context,
1434         .parameters             = hugetlb_fs_parameters,
1435         .kill_sb                = kill_litter_super,
1436 };
1437
1438 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1439
1440 static int can_do_hugetlb_shm(void)
1441 {
1442         kgid_t shm_group;
1443         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1444         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1445 }
1446
1447 static int get_hstate_idx(int page_size_log)
1448 {
1449         struct hstate *h = hstate_sizelog(page_size_log);
1450
1451         if (!h)
1452                 return -1;
1453         return h - hstates;
1454 }
1455
1456 /*
1457  * Note that size should be aligned to proper hugepage size in caller side,
1458  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1459  */
1460 struct file *hugetlb_file_setup(const char *name, size_t size,
1461                                 vm_flags_t acctflag, struct user_struct **user,
1462                                 int creat_flags, int page_size_log)
1463 {
1464         struct inode *inode;
1465         struct vfsmount *mnt;
1466         int hstate_idx;
1467         struct file *file;
1468
1469         hstate_idx = get_hstate_idx(page_size_log);
1470         if (hstate_idx < 0)
1471                 return ERR_PTR(-ENODEV);
1472
1473         *user = NULL;
1474         mnt = hugetlbfs_vfsmount[hstate_idx];
1475         if (!mnt)
1476                 return ERR_PTR(-ENOENT);
1477
1478         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1479                 *user = current_user();
1480                 if (user_shm_lock(size, *user)) {
1481                         task_lock(current);
1482                         pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
1483                                 current->comm, current->pid);
1484                         task_unlock(current);
1485                 } else {
1486                         *user = NULL;
1487                         return ERR_PTR(-EPERM);
1488                 }
1489         }
1490
1491         file = ERR_PTR(-ENOSPC);
1492         inode = hugetlbfs_get_inode(mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0);
1493         if (!inode)
1494                 goto out;
1495         if (creat_flags == HUGETLB_SHMFS_INODE)
1496                 inode->i_flags |= S_PRIVATE;
1497
1498         inode->i_size = size;
1499         clear_nlink(inode);
1500
1501         if (hugetlb_reserve_pages(inode, 0,
1502                         size >> huge_page_shift(hstate_inode(inode)), NULL,
1503                         acctflag))
1504                 file = ERR_PTR(-ENOMEM);
1505         else
1506                 file = alloc_file_pseudo(inode, mnt, name, O_RDWR,
1507                                         &hugetlbfs_file_operations);
1508         if (!IS_ERR(file))
1509                 return file;
1510
1511         iput(inode);
1512 out:
1513         if (*user) {
1514                 user_shm_unlock(size, *user);
1515                 *user = NULL;
1516         }
1517         return file;
1518 }
1519
1520 static struct vfsmount *__init mount_one_hugetlbfs(struct hstate *h)
1521 {
1522         struct fs_context *fc;
1523         struct vfsmount *mnt;
1524
1525         fc = fs_context_for_mount(&hugetlbfs_fs_type, SB_KERNMOUNT);
1526         if (IS_ERR(fc)) {
1527                 mnt = ERR_CAST(fc);
1528         } else {
1529                 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1530                 ctx->hstate = h;
1531                 mnt = fc_mount(fc);
1532                 put_fs_context(fc);
1533         }
1534         if (IS_ERR(mnt))
1535                 pr_err("Cannot mount internal hugetlbfs for page size %uK",
1536                        1U << (h->order + PAGE_SHIFT - 10));
1537         return mnt;
1538 }
1539
1540 static int __init init_hugetlbfs_fs(void)
1541 {
1542         struct vfsmount *mnt;
1543         struct hstate *h;
1544         int error;
1545         int i;
1546
1547         if (!hugepages_supported()) {
1548                 pr_info("disabling because there are no supported hugepage sizes\n");
1549                 return -ENOTSUPP;
1550         }
1551
1552         error = -ENOMEM;
1553         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1554                                         sizeof(struct hugetlbfs_inode_info),
1555                                         0, SLAB_ACCOUNT, init_once);
1556         if (hugetlbfs_inode_cachep == NULL)
1557                 goto out;
1558
1559         error = register_filesystem(&hugetlbfs_fs_type);
1560         if (error)
1561                 goto out_free;
1562
1563         /* default hstate mount is required */
1564         mnt = mount_one_hugetlbfs(&hstates[default_hstate_idx]);
1565         if (IS_ERR(mnt)) {
1566                 error = PTR_ERR(mnt);
1567                 goto out_unreg;
1568         }
1569         hugetlbfs_vfsmount[default_hstate_idx] = mnt;
1570
1571         /* other hstates are optional */
1572         i = 0;
1573         for_each_hstate(h) {
1574                 if (i == default_hstate_idx) {
1575                         i++;
1576                         continue;
1577                 }
1578
1579                 mnt = mount_one_hugetlbfs(h);
1580                 if (IS_ERR(mnt))
1581                         hugetlbfs_vfsmount[i] = NULL;
1582                 else
1583                         hugetlbfs_vfsmount[i] = mnt;
1584                 i++;
1585         }
1586
1587         return 0;
1588
1589  out_unreg:
1590         (void)unregister_filesystem(&hugetlbfs_fs_type);
1591  out_free:
1592         kmem_cache_destroy(hugetlbfs_inode_cachep);
1593  out:
1594         return error;
1595 }
1596 fs_initcall(init_hugetlbfs_fs)