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 static unsigned long
 199 hugetlb_get_unmapped_area_bottomup(struct file *file, unsigned long addr,
 200                 unsigned long len, unsigned long pgoff, unsigned long flags)
 201 {
 202         struct hstate *h = hstate_file(file);
 203         struct vm_unmapped_area_info info;
 204
 205         info.flags = 0;
 206         info.length = len;
 207         info.low_limit = current->mm->mmap_base;
 208         info.high_limit = arch_get_mmap_end(addr, len, flags);
 209         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 210         info.align_offset = 0;
 211         return vm_unmapped_area(&info);
 212 }
 213
 214 static unsigned long
 215 hugetlb_get_unmapped_area_topdown(struct file *file, unsigned long addr,
 216                 unsigned long len, unsigned long pgoff, unsigned long flags)
 217 {
 218         struct hstate *h = hstate_file(file);
 219         struct vm_unmapped_area_info info;
 220
 221         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 222         info.length = len;
 223         info.low_limit = max(PAGE_SIZE, mmap_min_addr);
 224         info.high_limit = arch_get_mmap_base(addr, current->mm->mmap_base);
 225         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 226         info.align_offset = 0;
 227         addr = vm_unmapped_area(&info);
 228
 229         /*
 230          * A failed mmap() very likely causes application failure,
 231          * so fall back to the bottom-up function here. This scenario
 232          * can happen with large stack limits and large mmap()
 233          * allocations.
 234          */
 235         if (unlikely(offset_in_page(addr))) {
 236                 VM_BUG_ON(addr != -ENOMEM);
 237                 info.flags = 0;
 238                 info.low_limit = current->mm->mmap_base;
 239                 info.high_limit = arch_get_mmap_end(addr, len, flags);
 240                 addr = vm_unmapped_area(&info);
 241         }
 242
 243         return addr;
 244 }
 245
 246 unsigned long
 247 generic_hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 248                                   unsigned long len, unsigned long pgoff,
 249                                   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, len, flags);
 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
 287 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 288 static unsigned long
 289 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 290                           unsigned long len, unsigned long pgoff,
 291                           unsigned long flags)
 292 {
 293         return generic_hugetlb_get_unmapped_area(file, addr, len, pgoff, flags);
 294 }
 295 #endif
 296
 297 static size_t
 298 hugetlbfs_read_actor(struct page *page, unsigned long offset,
 299                         struct iov_iter *to, unsigned long size)
 300 {
 301         size_t copied = 0;
 302         int i, chunksize;
 303
 304         /* Find which 4k chunk and offset with in that chunk */
 305         i = offset >> PAGE_SHIFT;
 306         offset = offset & ~PAGE_MASK;
 307
 308         while (size) {
 309                 size_t n;
 310                 chunksize = PAGE_SIZE;
 311                 if (offset)
 312                         chunksize -= offset;
 313                 if (chunksize > size)
 314                         chunksize = size;
 315                 n = copy_page_to_iter(&page[i], offset, chunksize, to);
 316                 copied += n;
 317                 if (n != chunksize)
 318                         return copied;
 319                 offset = 0;
 320                 size -= chunksize;
 321                 i++;
 322         }
 323         return copied;
 324 }
 325
 326 /*
 327  * Support for read() - Find the page attached to f_mapping and copy out the
 328  * data. Its *very* similar to generic_file_buffered_read(), we can't use that
 329  * since it has PAGE_SIZE assumptions.
 330  */
 331 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
 332 {
 333         struct file *file = iocb->ki_filp;
 334         struct hstate *h = hstate_file(file);
 335         struct address_space *mapping = file->f_mapping;
 336         struct inode *inode = mapping->host;
 337         unsigned long index = iocb->ki_pos >> huge_page_shift(h);
 338         unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
 339         unsigned long end_index;
 340         loff_t isize;
 341         ssize_t retval = 0;
 342
 343         while (iov_iter_count(to)) {
 344                 struct page *page;
 345                 size_t nr, copied;
 346
 347                 /* nr is the maximum number of bytes to copy from this page */
 348                 nr = huge_page_size(h);
 349                 isize = i_size_read(inode);
 350                 if (!isize)
 351                         break;
 352                 end_index = (isize - 1) >> huge_page_shift(h);
 353                 if (index > end_index)
 354                         break;
 355                 if (index == end_index) {
 356                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
 357                         if (nr <= offset)
 358                                 break;
 359                 }
 360                 nr = nr - offset;
 361
 362                 /* Find the page */
 363                 page = find_lock_page(mapping, index);
 364                 if (unlikely(page == NULL)) {
 365                         /*
 366                          * We have a HOLE, zero out the user-buffer for the
 367                          * length of the hole or request.
 368                          */
 369                         copied = iov_iter_zero(nr, to);
 370                 } else {
 371                         unlock_page(page);
 372
 373                         /*
 374                          * We have the page, copy it to user space buffer.
 375                          */
 376                         copied = hugetlbfs_read_actor(page, offset, to, nr);
 377                         put_page(page);
 378                 }
 379                 offset += copied;
 380                 retval += copied;
 381                 if (copied != nr && iov_iter_count(to)) {
 382                         if (!retval)
 383                                 retval = -EFAULT;
 384                         break;
 385                 }
 386                 index += offset >> huge_page_shift(h);
 387                 offset &= ~huge_page_mask(h);
 388         }
 389         iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
 390         return retval;
 391 }
 392
 393 static int hugetlbfs_write_begin(struct file *file,
 394                         struct address_space *mapping,
 395                         loff_t pos, unsigned len,
 396                         struct page **pagep, void **fsdata)
 397 {
 398         return -EINVAL;
 399 }
 400
 401 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
 402                         loff_t pos, unsigned len, unsigned copied,
 403                         struct page *page, void *fsdata)
 404 {
 405         BUG();
 406         return -EINVAL;
 407 }
 408
 409 static void remove_huge_page(struct page *page)
 410 {
 411         ClearPageDirty(page);
 412         ClearPageUptodate(page);
 413         delete_from_page_cache(page);
 414 }
 415
 416 static void
 417 hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end,
 418                       zap_flags_t zap_flags)
 419 {
 420         struct vm_area_struct *vma;
 421
 422         /*
 423          * end == 0 indicates that the entire range after start should be
 424          * unmapped.  Note, end is exclusive, whereas the interval tree takes
 425          * an inclusive "last".
 426          */
 427         vma_interval_tree_foreach(vma, root, start, end ? end - 1 : ULONG_MAX) {
 428                 unsigned long v_offset;
 429                 unsigned long v_end;
 430
 431                 /*
 432                  * Can the expression below overflow on 32-bit arches?
 433                  * No, because the interval tree returns us only those vmas
 434                  * which overlap the truncated area starting at pgoff,
 435                  * and no vma on a 32-bit arch can span beyond the 4GB.
 436                  */
 437                 if (vma->vm_pgoff < start)
 438                         v_offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
 439                 else
 440                         v_offset = 0;
 441
 442                 if (!end)
 443                         v_end = vma->vm_end;
 444                 else {
 445                         v_end = ((end - vma->vm_pgoff) << PAGE_SHIFT)
 446                                                         + vma->vm_start;
 447                         if (v_end > vma->vm_end)
 448                                 v_end = vma->vm_end;
 449                 }
 450
 451                 unmap_hugepage_range(vma, vma->vm_start + v_offset, v_end,
 452                                      NULL, zap_flags);
 453         }
 454 }
 455
 456 /*
 457  * remove_inode_hugepages handles two distinct cases: truncation and hole
 458  * punch.  There are subtle differences in operation for each case.
 459  *
 460  * truncation is indicated by end of range being LLONG_MAX
 461  *      In this case, we first scan the range and release found pages.
 462  *      After releasing pages, hugetlb_unreserve_pages cleans up region/reserve
 463  *      maps and global counts.  Page faults can not race with truncation
 464  *      in this routine.  hugetlb_no_page() holds i_mmap_rwsem and prevents
 465  *      page faults in the truncated range by checking i_size.  i_size is
 466  *      modified while holding i_mmap_rwsem.
 467  * hole punch is indicated if end is not LLONG_MAX
 468  *      In the hole punch case we scan the range and release found pages.
 469  *      Only when releasing a page is the associated region/reserve map
 470  *      deleted.  The region/reserve map for ranges without associated
 471  *      pages are not modified.  Page faults can race with hole punch.
 472  *      This is indicated if we find a mapped page.
 473  * Note: If the passed end of range value is beyond the end of file, but
 474  * not LLONG_MAX this routine still performs a hole punch operation.
 475  */
 476 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 477                                    loff_t lend)
 478 {
 479         struct hstate *h = hstate_inode(inode);
 480         struct address_space *mapping = &inode->i_data;
 481         const pgoff_t start = lstart >> huge_page_shift(h);
 482         const pgoff_t end = lend >> huge_page_shift(h);
 483         struct pagevec pvec;
 484         pgoff_t next, index;
 485         int i, freed = 0;
 486         bool truncate_op = (lend == LLONG_MAX);
 487
 488         pagevec_init(&pvec);
 489         next = start;
 490         while (next < end) {
 491                 /*
 492                  * When no more pages are found, we are done.
 493                  */
 494                 if (!pagevec_lookup_range(&pvec, mapping, &next, end - 1))
 495                         break;
 496
 497                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 498                         struct page *page = pvec.pages[i];
 499                         u32 hash = 0;
 500
 501                         index = page->index;
 502                         if (!truncate_op) {
 503                                 /*
 504                                  * Only need to hold the fault mutex in the
 505                                  * hole punch case.  This prevents races with
 506                                  * page faults.  Races are not possible in the
 507                                  * case of truncation.
 508                                  */
 509                                 hash = hugetlb_fault_mutex_hash(mapping, index);
 510                                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
 511                         }
 512
 513                         /*
 514                          * If page is mapped, it was faulted in after being
 515                          * unmapped in caller.  Unmap (again) now after taking
 516                          * the fault mutex.  The mutex will prevent faults
 517                          * until we finish removing the page.
 518                          *
 519                          * This race can only happen in the hole punch case.
 520                          * Getting here in a truncate operation is a bug.
 521                          */
 522                         if (unlikely(page_mapped(page))) {
 523                                 BUG_ON(truncate_op);
 524
 525                                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 526                                 i_mmap_lock_write(mapping);
 527                                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
 528                                 hugetlb_vmdelete_list(&mapping->i_mmap,
 529                                         index * pages_per_huge_page(h),
 530                                         (index + 1) * pages_per_huge_page(h),
 531                                         ZAP_FLAG_DROP_MARKER);
 532                                 i_mmap_unlock_write(mapping);
 533                         }
 534
 535                         lock_page(page);
 536                         /*
 537                          * We must free the huge page and remove from page
 538                          * cache (remove_huge_page) BEFORE removing the
 539                          * region/reserve map (hugetlb_unreserve_pages).  In
 540                          * rare out of memory conditions, removal of the
 541                          * region/reserve map could fail. Correspondingly,
 542                          * the subpool and global reserve usage count can need
 543                          * to be adjusted.
 544                          */
 545                         VM_BUG_ON(HPageRestoreReserve(page));
 546                         remove_huge_page(page);
 547                         freed++;
 548                         if (!truncate_op) {
 549                                 if (unlikely(hugetlb_unreserve_pages(inode,
 550                                                         index, index + 1, 1)))
 551                                         hugetlb_fix_reserve_counts(inode);
 552                         }
 553
 554                         unlock_page(page);
 555                         if (!truncate_op)
 556                                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 557                 }
 558                 huge_pagevec_release(&pvec);
 559                 cond_resched();
 560         }
 561
 562         if (truncate_op)
 563                 (void)hugetlb_unreserve_pages(inode, start, LONG_MAX, freed);
 564 }
 565
 566 static void hugetlbfs_evict_inode(struct inode *inode)
 567 {
 568         struct resv_map *resv_map;
 569
 570         remove_inode_hugepages(inode, 0, LLONG_MAX);
 571
 572         /*
 573          * Get the resv_map from the address space embedded in the inode.
 574          * This is the address space which points to any resv_map allocated
 575          * at inode creation time.  If this is a device special inode,
 576          * i_mapping may not point to the original address space.
 577          */
 578         resv_map = (struct resv_map *)(&inode->i_data)->private_data;
 579         /* Only regular and link inodes have associated reserve maps */
 580         if (resv_map)
 581                 resv_map_release(&resv_map->refs);
 582         clear_inode(inode);
 583 }
 584
 585 static void hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 586 {
 587         pgoff_t pgoff;
 588         struct address_space *mapping = inode->i_mapping;
 589         struct hstate *h = hstate_inode(inode);
 590
 591         BUG_ON(offset & ~huge_page_mask(h));
 592         pgoff = offset >> PAGE_SHIFT;
 593
 594         i_mmap_lock_write(mapping);
 595         i_size_write(inode, offset);
 596         if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
 597                 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0,
 598                                       ZAP_FLAG_DROP_MARKER);
 599         i_mmap_unlock_write(mapping);
 600         remove_inode_hugepages(inode, offset, LLONG_MAX);
 601 }
 602
 603 static void hugetlbfs_zero_partial_page(struct hstate *h,
 604                                         struct address_space *mapping,
 605                                         loff_t start,
 606                                         loff_t end)
 607 {
 608         pgoff_t idx = start >> huge_page_shift(h);
 609         struct folio *folio;
 610
 611         folio = filemap_lock_folio(mapping, idx);
 612         if (!folio)
 613                 return;
 614
 615         start = start & ~huge_page_mask(h);
 616         end = end & ~huge_page_mask(h);
 617         if (!end)
 618                 end = huge_page_size(h);
 619
 620         folio_zero_segment(folio, (size_t)start, (size_t)end);
 621
 622         folio_unlock(folio);
 623         folio_put(folio);
 624 }
 625
 626 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
 627 {
 628         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 629         struct address_space *mapping = inode->i_mapping;
 630         struct hstate *h = hstate_inode(inode);
 631         loff_t hpage_size = huge_page_size(h);
 632         loff_t hole_start, hole_end;
 633
 634         /*
 635          * hole_start and hole_end indicate the full pages within the hole.
 636          */
 637         hole_start = round_up(offset, hpage_size);
 638         hole_end = round_down(offset + len, hpage_size);
 639
 640         inode_lock(inode);
 641
 642         /* protected by i_rwsem */
 643         if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) {
 644                 inode_unlock(inode);
 645                 return -EPERM;
 646         }
 647
 648         i_mmap_lock_write(mapping);
 649
 650         /* If range starts before first full page, zero partial page. */
 651         if (offset < hole_start)
 652                 hugetlbfs_zero_partial_page(h, mapping,
 653                                 offset, min(offset + len, hole_start));
 654
 655         /* Unmap users of full pages in the hole. */
 656         if (hole_end > hole_start) {
 657                 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
 658                         hugetlb_vmdelete_list(&mapping->i_mmap,
 659                                               hole_start >> PAGE_SHIFT,
 660                                               hole_end >> PAGE_SHIFT, 0);
 661         }
 662
 663         /* If range extends beyond last full page, zero partial page. */
 664         if ((offset + len) > hole_end && (offset + len) > hole_start)
 665                 hugetlbfs_zero_partial_page(h, mapping,
 666                                 hole_end, offset + len);
 667
 668         i_mmap_unlock_write(mapping);
 669
 670         /* Remove full pages from the file. */
 671         if (hole_end > hole_start)
 672                 remove_inode_hugepages(inode, hole_start, hole_end);
 673
 674         inode_unlock(inode);
 675
 676         return 0;
 677 }
 678
 679 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
 680                                 loff_t len)
 681 {
 682         struct inode *inode = file_inode(file);
 683         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 684         struct address_space *mapping = inode->i_mapping;
 685         struct hstate *h = hstate_inode(inode);
 686         struct vm_area_struct pseudo_vma;
 687         struct mm_struct *mm = current->mm;
 688         loff_t hpage_size = huge_page_size(h);
 689         unsigned long hpage_shift = huge_page_shift(h);
 690         pgoff_t start, index, end;
 691         int error;
 692         u32 hash;
 693
 694         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
 695                 return -EOPNOTSUPP;
 696
 697         if (mode & FALLOC_FL_PUNCH_HOLE)
 698                 return hugetlbfs_punch_hole(inode, offset, len);
 699
 700         /*
 701          * Default preallocate case.
 702          * For this range, start is rounded down and end is rounded up
 703          * as well as being converted to page offsets.
 704          */
 705         start = offset >> hpage_shift;
 706         end = (offset + len + hpage_size - 1) >> hpage_shift;
 707
 708         inode_lock(inode);
 709
 710         /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
 711         error = inode_newsize_ok(inode, offset + len);
 712         if (error)
 713                 goto out;
 714
 715         if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) {
 716                 error = -EPERM;
 717                 goto out;
 718         }
 719
 720         /*
 721          * Initialize a pseudo vma as this is required by the huge page
 722          * allocation routines.  If NUMA is configured, use page index
 723          * as input to create an allocation policy.
 724          */
 725         vma_init(&pseudo_vma, mm);
 726         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
 727         pseudo_vma.vm_file = file;
 728
 729         for (index = start; index < end; index++) {
 730                 /*
 731                  * This is supposed to be the vaddr where the page is being
 732                  * faulted in, but we have no vaddr here.
 733                  */
 734                 struct page *page;
 735                 unsigned long addr;
 736
 737                 cond_resched();
 738
 739                 /*
 740                  * fallocate(2) manpage permits EINTR; we may have been
 741                  * interrupted because we are using up too much memory.
 742                  */
 743                 if (signal_pending(current)) {
 744                         error = -EINTR;
 745                         break;
 746                 }
 747
 748                 /* Set numa allocation policy based on index */
 749                 hugetlb_set_vma_policy(&pseudo_vma, inode, index);
 750
 751                 /* addr is the offset within the file (zero based) */
 752                 addr = index * hpage_size;
 753
 754                 /*
 755                  * fault mutex taken here, protects against fault path
 756                  * and hole punch.  inode_lock previously taken protects
 757                  * against truncation.
 758                  */
 759                 hash = hugetlb_fault_mutex_hash(mapping, index);
 760                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
 761
 762                 /* See if already present in mapping to avoid alloc/free */
 763                 page = find_get_page(mapping, index);
 764                 if (page) {
 765                         put_page(page);
 766                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 767                         hugetlb_drop_vma_policy(&pseudo_vma);
 768                         continue;
 769                 }
 770
 771                 /*
 772                  * Allocate page without setting the avoid_reserve argument.
 773                  * There certainly are no reserves associated with the
 774                  * pseudo_vma.  However, there could be shared mappings with
 775                  * reserves for the file at the inode level.  If we fallocate
 776                  * pages in these areas, we need to consume the reserves
 777                  * to keep reservation accounting consistent.
 778                  */
 779                 page = alloc_huge_page(&pseudo_vma, addr, 0);
 780                 hugetlb_drop_vma_policy(&pseudo_vma);
 781                 if (IS_ERR(page)) {
 782                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 783                         error = PTR_ERR(page);
 784                         goto out;
 785                 }
 786                 clear_huge_page(page, addr, pages_per_huge_page(h));
 787                 __SetPageUptodate(page);
 788                 error = huge_add_to_page_cache(page, mapping, index);
 789                 if (unlikely(error)) {
 790                         restore_reserve_on_error(h, &pseudo_vma, addr, page);
 791                         put_page(page);
 792                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 793                         goto out;
 794                 }
 795
 796                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 797
 798                 SetHPageMigratable(page);
 799                 /*
 800                  * unlock_page because locked by add_to_page_cache()
 801                  * put_page() due to reference from alloc_huge_page()
 802                  */
 803                 unlock_page(page);
 804                 put_page(page);
 805         }
 806
 807         if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
 808                 i_size_write(inode, offset + len);
 809         inode->i_ctime = current_time(inode);
 810 out:
 811         inode_unlock(inode);
 812         return error;
 813 }
 814
 815 static int hugetlbfs_setattr(struct user_namespace *mnt_userns,
 816                              struct dentry *dentry, struct iattr *attr)
 817 {
 818         struct inode *inode = d_inode(dentry);
 819         struct hstate *h = hstate_inode(inode);
 820         int error;
 821         unsigned int ia_valid = attr->ia_valid;
 822         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 823
 824         error = setattr_prepare(&init_user_ns, dentry, attr);
 825         if (error)
 826                 return error;
 827
 828         if (ia_valid & ATTR_SIZE) {
 829                 loff_t oldsize = inode->i_size;
 830                 loff_t newsize = attr->ia_size;
 831
 832                 if (newsize & ~huge_page_mask(h))
 833                         return -EINVAL;
 834                 /* protected by i_rwsem */
 835                 if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
 836                     (newsize > oldsize && (info->seals & F_SEAL_GROW)))
 837                         return -EPERM;
 838                 hugetlb_vmtruncate(inode, newsize);
 839         }
 840
 841         setattr_copy(&init_user_ns, inode, attr);
 842         mark_inode_dirty(inode);
 843         return 0;
 844 }
 845
 846 static struct inode *hugetlbfs_get_root(struct super_block *sb,
 847                                         struct hugetlbfs_fs_context *ctx)
 848 {
 849         struct inode *inode;
 850
 851         inode = new_inode(sb);
 852         if (inode) {
 853                 inode->i_ino = get_next_ino();
 854                 inode->i_mode = S_IFDIR | ctx->mode;
 855                 inode->i_uid = ctx->uid;
 856                 inode->i_gid = ctx->gid;
 857                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 858                 inode->i_op = &hugetlbfs_dir_inode_operations;
 859                 inode->i_fop = &simple_dir_operations;
 860                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
 861                 inc_nlink(inode);
 862                 lockdep_annotate_inode_mutex_key(inode);
 863         }
 864         return inode;
 865 }
 866
 867 /*
 868  * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
 869  * be taken from reclaim -- unlike regular filesystems. This needs an
 870  * annotation because huge_pmd_share() does an allocation under hugetlb's
 871  * i_mmap_rwsem.
 872  */
 873 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
 874
 875 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 876                                         struct inode *dir,
 877                                         umode_t mode, dev_t dev)
 878 {
 879         struct inode *inode;
 880         struct resv_map *resv_map = NULL;
 881
 882         /*
 883          * Reserve maps are only needed for inodes that can have associated
 884          * page allocations.
 885          */
 886         if (S_ISREG(mode) || S_ISLNK(mode)) {
 887                 resv_map = resv_map_alloc();
 888                 if (!resv_map)
 889                         return NULL;
 890         }
 891
 892         inode = new_inode(sb);
 893         if (inode) {
 894                 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 895
 896                 inode->i_ino = get_next_ino();
 897                 inode_init_owner(&init_user_ns, inode, dir, mode);
 898                 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
 899                                 &hugetlbfs_i_mmap_rwsem_key);
 900                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 901                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 902                 inode->i_mapping->private_data = resv_map;
 903                 info->seals = F_SEAL_SEAL;
 904                 switch (mode & S_IFMT) {
 905                 default:
 906                         init_special_inode(inode, mode, dev);
 907                         break;
 908                 case S_IFREG:
 909                         inode->i_op = &hugetlbfs_inode_operations;
 910                         inode->i_fop = &hugetlbfs_file_operations;
 911                         break;
 912                 case S_IFDIR:
 913                         inode->i_op = &hugetlbfs_dir_inode_operations;
 914                         inode->i_fop = &simple_dir_operations;
 915
 916                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 917                         inc_nlink(inode);
 918                         break;
 919                 case S_IFLNK:
 920                         inode->i_op = &page_symlink_inode_operations;
 921                         inode_nohighmem(inode);
 922                         break;
 923                 }
 924                 lockdep_annotate_inode_mutex_key(inode);
 925         } else {
 926                 if (resv_map)
 927                         kref_put(&resv_map->refs, resv_map_release);
 928         }
 929
 930         return inode;
 931 }
 932
 933 /*
 934  * File creation. Allocate an inode, and we're done..
 935  */
 936 static int do_hugetlbfs_mknod(struct inode *dir,
 937                         struct dentry *dentry,
 938                         umode_t mode,
 939                         dev_t dev,
 940                         bool tmpfile)
 941 {
 942         struct inode *inode;
 943         int error = -ENOSPC;
 944
 945         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
 946         if (inode) {
 947                 dir->i_ctime = dir->i_mtime = current_time(dir);
 948                 if (tmpfile) {
 949                         d_tmpfile(dentry, inode);
 950                 } else {
 951                         d_instantiate(dentry, inode);
 952                         dget(dentry);/* Extra count - pin the dentry in core */
 953                 }
 954                 error = 0;
 955         }
 956         return error;
 957 }
 958
 959 static int hugetlbfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
 960                            struct dentry *dentry, umode_t mode, dev_t dev)
 961 {
 962         return do_hugetlbfs_mknod(dir, dentry, mode, dev, false);
 963 }
 964
 965 static int hugetlbfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
 966                            struct dentry *dentry, umode_t mode)
 967 {
 968         int retval = hugetlbfs_mknod(&init_user_ns, dir, dentry,
 969                                      mode | S_IFDIR, 0);
 970         if (!retval)
 971                 inc_nlink(dir);
 972         return retval;
 973 }
 974
 975 static int hugetlbfs_create(struct user_namespace *mnt_userns,
 976                             struct inode *dir, struct dentry *dentry,
 977                             umode_t mode, bool excl)
 978 {
 979         return hugetlbfs_mknod(&init_user_ns, dir, dentry, mode | S_IFREG, 0);
 980 }
 981
 982 static int hugetlbfs_tmpfile(struct user_namespace *mnt_userns,
 983                              struct inode *dir, struct dentry *dentry,
 984                              umode_t mode)
 985 {
 986         return do_hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0, true);
 987 }
 988
 989 static int hugetlbfs_symlink(struct user_namespace *mnt_userns,
 990                              struct inode *dir, struct dentry *dentry,
 991                              const char *symname)
 992 {
 993         struct inode *inode;
 994         int error = -ENOSPC;
 995
 996         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
 997         if (inode) {
 998                 int l = strlen(symname)+1;
 999                 error = page_symlink(inode, symname, l);
1000                 if (!error) {
1001                         d_instantiate(dentry, inode);
1002                         dget(dentry);
1003                 } else
1004                         iput(inode);
1005         }
1006         dir->i_ctime = dir->i_mtime = current_time(dir);
1007
1008         return error;
1009 }
1010
1011 static int hugetlbfs_migrate_page(struct address_space *mapping,
1012                                 struct page *newpage, struct page *page,
1013                                 enum migrate_mode mode)
1014 {
1015         int rc;
1016
1017         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
1018         if (rc != MIGRATEPAGE_SUCCESS)
1019                 return rc;
1020
1021         if (hugetlb_page_subpool(page)) {
1022                 hugetlb_set_page_subpool(newpage, hugetlb_page_subpool(page));
1023                 hugetlb_set_page_subpool(page, NULL);
1024         }
1025
1026         if (mode != MIGRATE_SYNC_NO_COPY)
1027                 migrate_page_copy(newpage, page);
1028         else
1029                 migrate_page_states(newpage, page);
1030
1031         return MIGRATEPAGE_SUCCESS;
1032 }
1033
1034 static int hugetlbfs_error_remove_page(struct address_space *mapping,
1035                                 struct page *page)
1036 {
1037         struct inode *inode = mapping->host;
1038         pgoff_t index = page->index;
1039
1040         remove_huge_page(page);
1041         if (unlikely(hugetlb_unreserve_pages(inode, index, index + 1, 1)))
1042                 hugetlb_fix_reserve_counts(inode);
1043
1044         return 0;
1045 }
1046
1047 /*
1048  * Display the mount options in /proc/mounts.
1049  */
1050 static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root)
1051 {
1052         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(root->d_sb);
1053         struct hugepage_subpool *spool = sbinfo->spool;
1054         unsigned long hpage_size = huge_page_size(sbinfo->hstate);
1055         unsigned hpage_shift = huge_page_shift(sbinfo->hstate);
1056         char mod;
1057
1058         if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
1059                 seq_printf(m, ",uid=%u",
1060                            from_kuid_munged(&init_user_ns, sbinfo->uid));
1061         if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
1062                 seq_printf(m, ",gid=%u",
1063                            from_kgid_munged(&init_user_ns, sbinfo->gid));
1064         if (sbinfo->mode != 0755)
1065                 seq_printf(m, ",mode=%o", sbinfo->mode);
1066         if (sbinfo->max_inodes != -1)
1067                 seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes);
1068
1069         hpage_size /= 1024;
1070         mod = 'K';
1071         if (hpage_size >= 1024) {
1072                 hpage_size /= 1024;
1073                 mod = 'M';
1074         }
1075         seq_printf(m, ",pagesize=%lu%c", hpage_size, mod);
1076         if (spool) {
1077                 if (spool->max_hpages != -1)
1078                         seq_printf(m, ",size=%llu",
1079                                    (unsigned long long)spool->max_hpages << hpage_shift);
1080                 if (spool->min_hpages != -1)
1081                         seq_printf(m, ",min_size=%llu",
1082                                    (unsigned long long)spool->min_hpages << hpage_shift);
1083         }
1084         return 0;
1085 }
1086
1087 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1088 {
1089         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
1090         struct hstate *h = hstate_inode(d_inode(dentry));
1091
1092         buf->f_type = HUGETLBFS_MAGIC;
1093         buf->f_bsize = huge_page_size(h);
1094         if (sbinfo) {
1095                 spin_lock(&sbinfo->stat_lock);
1096                 /* If no limits set, just report 0 for max/free/used
1097                  * blocks, like simple_statfs() */
1098                 if (sbinfo->spool) {
1099                         long free_pages;
1100
1101                         spin_lock_irq(&sbinfo->spool->lock);
1102                         buf->f_blocks = sbinfo->spool->max_hpages;
1103                         free_pages = sbinfo->spool->max_hpages
1104                                 - sbinfo->spool->used_hpages;
1105                         buf->f_bavail = buf->f_bfree = free_pages;
1106                         spin_unlock_irq(&sbinfo->spool->lock);
1107                         buf->f_files = sbinfo->max_inodes;
1108                         buf->f_ffree = sbinfo->free_inodes;
1109                 }
1110                 spin_unlock(&sbinfo->stat_lock);
1111         }
1112         buf->f_namelen = NAME_MAX;
1113         return 0;
1114 }
1115
1116 static void hugetlbfs_put_super(struct super_block *sb)
1117 {
1118         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
1119
1120         if (sbi) {
1121                 sb->s_fs_info = NULL;
1122
1123                 if (sbi->spool)
1124                         hugepage_put_subpool(sbi->spool);
1125
1126                 kfree(sbi);
1127         }
1128 }
1129
1130 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1131 {
1132         if (sbinfo->free_inodes >= 0) {
1133                 spin_lock(&sbinfo->stat_lock);
1134                 if (unlikely(!sbinfo->free_inodes)) {
1135                         spin_unlock(&sbinfo->stat_lock);
1136                         return 0;
1137                 }
1138                 sbinfo->free_inodes--;
1139                 spin_unlock(&sbinfo->stat_lock);
1140         }
1141
1142         return 1;
1143 }
1144
1145 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1146 {
1147         if (sbinfo->free_inodes >= 0) {
1148                 spin_lock(&sbinfo->stat_lock);
1149                 sbinfo->free_inodes++;
1150                 spin_unlock(&sbinfo->stat_lock);
1151         }
1152 }
1153
1154
1155 static struct kmem_cache *hugetlbfs_inode_cachep;
1156
1157 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
1158 {
1159         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
1160         struct hugetlbfs_inode_info *p;
1161
1162         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
1163                 return NULL;
1164         p = alloc_inode_sb(sb, hugetlbfs_inode_cachep, GFP_KERNEL);
1165         if (unlikely(!p)) {
1166                 hugetlbfs_inc_free_inodes(sbinfo);
1167                 return NULL;
1168         }
1169
1170         /*
1171          * Any time after allocation, hugetlbfs_destroy_inode can be called
1172          * for the inode.  mpol_free_shared_policy is unconditionally called
1173          * as part of hugetlbfs_destroy_inode.  So, initialize policy here
1174          * in case of a quick call to destroy.
1175          *
1176          * Note that the policy is initialized even if we are creating a
1177          * private inode.  This simplifies hugetlbfs_destroy_inode.
1178          */
1179         mpol_shared_policy_init(&p->policy, NULL);
1180
1181         return &p->vfs_inode;
1182 }
1183
1184 static void hugetlbfs_free_inode(struct inode *inode)
1185 {
1186         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
1187 }
1188
1189 static void hugetlbfs_destroy_inode(struct inode *inode)
1190 {
1191         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
1192         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
1193 }
1194
1195 static const struct address_space_operations hugetlbfs_aops = {
1196         .write_begin    = hugetlbfs_write_begin,
1197         .write_end      = hugetlbfs_write_end,
1198         .dirty_folio    = noop_dirty_folio,
1199         .migratepage    = hugetlbfs_migrate_page,
1200         .error_remove_page      = hugetlbfs_error_remove_page,
1201 };
1202
1203
1204 static void init_once(void *foo)
1205 {
1206         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
1207
1208         inode_init_once(&ei->vfs_inode);
1209 }
1210
1211 const struct file_operations hugetlbfs_file_operations = {
1212         .read_iter              = hugetlbfs_read_iter,
1213         .mmap                   = hugetlbfs_file_mmap,
1214         .fsync                  = noop_fsync,
1215         .get_unmapped_area      = hugetlb_get_unmapped_area,
1216         .llseek                 = default_llseek,
1217         .fallocate              = hugetlbfs_fallocate,
1218 };
1219
1220 static const struct inode_operations hugetlbfs_dir_inode_operations = {
1221         .create         = hugetlbfs_create,
1222         .lookup         = simple_lookup,
1223         .link           = simple_link,
1224         .unlink         = simple_unlink,
1225         .symlink        = hugetlbfs_symlink,
1226         .mkdir          = hugetlbfs_mkdir,
1227         .rmdir          = simple_rmdir,
1228         .mknod          = hugetlbfs_mknod,
1229         .rename         = simple_rename,
1230         .setattr        = hugetlbfs_setattr,
1231         .tmpfile        = hugetlbfs_tmpfile,
1232 };
1233
1234 static const struct inode_operations hugetlbfs_inode_operations = {
1235         .setattr        = hugetlbfs_setattr,
1236 };
1237
1238 static const struct super_operations hugetlbfs_ops = {
1239         .alloc_inode    = hugetlbfs_alloc_inode,
1240         .free_inode     = hugetlbfs_free_inode,
1241         .destroy_inode  = hugetlbfs_destroy_inode,
1242         .evict_inode    = hugetlbfs_evict_inode,
1243         .statfs         = hugetlbfs_statfs,
1244         .put_super      = hugetlbfs_put_super,
1245         .show_options   = hugetlbfs_show_options,
1246 };
1247
1248 /*
1249  * Convert size option passed from command line to number of huge pages
1250  * in the pool specified by hstate.  Size option could be in bytes
1251  * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1252  */
1253 static long
1254 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1255                          enum hugetlbfs_size_type val_type)
1256 {
1257         if (val_type == NO_SIZE)
1258                 return -1;
1259
1260         if (val_type == SIZE_PERCENT) {
1261                 size_opt <<= huge_page_shift(h);
1262                 size_opt *= h->max_huge_pages;
1263                 do_div(size_opt, 100);
1264         }
1265
1266         size_opt >>= huge_page_shift(h);
1267         return size_opt;
1268 }
1269
1270 /*
1271  * Parse one mount parameter.
1272  */
1273 static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1274 {
1275         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1276         struct fs_parse_result result;
1277         char *rest;
1278         unsigned long ps;
1279         int opt;
1280
1281         opt = fs_parse(fc, hugetlb_fs_parameters, param, &result);
1282         if (opt < 0)
1283                 return opt;
1284
1285         switch (opt) {
1286         case Opt_uid:
1287                 ctx->uid = make_kuid(current_user_ns(), result.uint_32);
1288                 if (!uid_valid(ctx->uid))
1289                         goto bad_val;
1290                 return 0;
1291
1292         case Opt_gid:
1293                 ctx->gid = make_kgid(current_user_ns(), result.uint_32);
1294                 if (!gid_valid(ctx->gid))
1295                         goto bad_val;
1296                 return 0;
1297
1298         case Opt_mode:
1299                 ctx->mode = result.uint_32 & 01777U;
1300                 return 0;
1301
1302         case Opt_size:
1303                 /* memparse() will accept a K/M/G without a digit */
1304                 if (!isdigit(param->string[0]))
1305                         goto bad_val;
1306                 ctx->max_size_opt = memparse(param->string, &rest);
1307                 ctx->max_val_type = SIZE_STD;
1308                 if (*rest == '%')
1309                         ctx->max_val_type = SIZE_PERCENT;
1310                 return 0;
1311
1312         case Opt_nr_inodes:
1313                 /* memparse() will accept a K/M/G without a digit */
1314                 if (!isdigit(param->string[0]))
1315                         goto bad_val;
1316                 ctx->nr_inodes = memparse(param->string, &rest);
1317                 return 0;
1318
1319         case Opt_pagesize:
1320                 ps = memparse(param->string, &rest);
1321                 ctx->hstate = size_to_hstate(ps);
1322                 if (!ctx->hstate) {
1323                         pr_err("Unsupported page size %lu MB\n", ps >> 20);
1324                         return -EINVAL;
1325                 }
1326                 return 0;
1327
1328         case Opt_min_size:
1329                 /* memparse() will accept a K/M/G without a digit */
1330                 if (!isdigit(param->string[0]))
1331                         goto bad_val;
1332                 ctx->min_size_opt = memparse(param->string, &rest);
1333                 ctx->min_val_type = SIZE_STD;
1334                 if (*rest == '%')
1335                         ctx->min_val_type = SIZE_PERCENT;
1336                 return 0;
1337
1338         default:
1339                 return -EINVAL;
1340         }
1341
1342 bad_val:
1343         return invalfc(fc, "Bad value '%s' for mount option '%s'\n",
1344                       param->string, param->key);
1345 }
1346
1347 /*
1348  * Validate the parsed options.
1349  */
1350 static int hugetlbfs_validate(struct fs_context *fc)
1351 {
1352         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1353
1354         /*
1355          * Use huge page pool size (in hstate) to convert the size
1356          * options to number of huge pages.  If NO_SIZE, -1 is returned.
1357          */
1358         ctx->max_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1359                                                    ctx->max_size_opt,
1360                                                    ctx->max_val_type);
1361         ctx->min_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1362                                                    ctx->min_size_opt,
1363                                                    ctx->min_val_type);
1364
1365         /*
1366          * If max_size was specified, then min_size must be smaller
1367          */
1368         if (ctx->max_val_type > NO_SIZE &&
1369             ctx->min_hpages > ctx->max_hpages) {
1370                 pr_err("Minimum size can not be greater than maximum size\n");
1371                 return -EINVAL;
1372         }
1373
1374         return 0;
1375 }
1376
1377 static int
1378 hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc)
1379 {
1380         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1381         struct hugetlbfs_sb_info *sbinfo;
1382
1383         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1384         if (!sbinfo)
1385                 return -ENOMEM;
1386         sb->s_fs_info = sbinfo;
1387         spin_lock_init(&sbinfo->stat_lock);
1388         sbinfo->hstate          = ctx->hstate;
1389         sbinfo->max_inodes      = ctx->nr_inodes;
1390         sbinfo->free_inodes     = ctx->nr_inodes;
1391         sbinfo->spool           = NULL;
1392         sbinfo->uid             = ctx->uid;
1393         sbinfo->gid             = ctx->gid;
1394         sbinfo->mode            = ctx->mode;
1395
1396         /*
1397          * Allocate and initialize subpool if maximum or minimum size is
1398          * specified.  Any needed reservations (for minimum size) are taken
1399          * taken when the subpool is created.
1400          */
1401         if (ctx->max_hpages != -1 || ctx->min_hpages != -1) {
1402                 sbinfo->spool = hugepage_new_subpool(ctx->hstate,
1403                                                      ctx->max_hpages,
1404                                                      ctx->min_hpages);
1405                 if (!sbinfo->spool)
1406                         goto out_free;
1407         }
1408         sb->s_maxbytes = MAX_LFS_FILESIZE;
1409         sb->s_blocksize = huge_page_size(ctx->hstate);
1410         sb->s_blocksize_bits = huge_page_shift(ctx->hstate);
1411         sb->s_magic = HUGETLBFS_MAGIC;
1412         sb->s_op = &hugetlbfs_ops;
1413         sb->s_time_gran = 1;
1414
1415         /*
1416          * Due to the special and limited functionality of hugetlbfs, it does
1417          * not work well as a stacking filesystem.
1418          */
1419         sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
1420         sb->s_root = d_make_root(hugetlbfs_get_root(sb, ctx));
1421         if (!sb->s_root)
1422                 goto out_free;
1423         return 0;
1424 out_free:
1425         kfree(sbinfo->spool);
1426         kfree(sbinfo);
1427         return -ENOMEM;
1428 }
1429
1430 static int hugetlbfs_get_tree(struct fs_context *fc)
1431 {
1432         int err = hugetlbfs_validate(fc);
1433         if (err)
1434                 return err;
1435         return get_tree_nodev(fc, hugetlbfs_fill_super);
1436 }
1437
1438 static void hugetlbfs_fs_context_free(struct fs_context *fc)
1439 {
1440         kfree(fc->fs_private);
1441 }
1442
1443 static const struct fs_context_operations hugetlbfs_fs_context_ops = {
1444         .free           = hugetlbfs_fs_context_free,
1445         .parse_param    = hugetlbfs_parse_param,
1446         .get_tree       = hugetlbfs_get_tree,
1447 };
1448
1449 static int hugetlbfs_init_fs_context(struct fs_context *fc)
1450 {
1451         struct hugetlbfs_fs_context *ctx;
1452
1453         ctx = kzalloc(sizeof(struct hugetlbfs_fs_context), GFP_KERNEL);
1454         if (!ctx)
1455                 return -ENOMEM;
1456
1457         ctx->max_hpages = -1; /* No limit on size by default */
1458         ctx->nr_inodes  = -1; /* No limit on number of inodes by default */
1459         ctx->uid        = current_fsuid();
1460         ctx->gid        = current_fsgid();
1461         ctx->mode       = 0755;
1462         ctx->hstate     = &default_hstate;
1463         ctx->min_hpages = -1; /* No default minimum size */
1464         ctx->max_val_type = NO_SIZE;
1465         ctx->min_val_type = NO_SIZE;
1466         fc->fs_private = ctx;
1467         fc->ops = &hugetlbfs_fs_context_ops;
1468         return 0;
1469 }
1470
1471 static struct file_system_type hugetlbfs_fs_type = {
1472         .name                   = "hugetlbfs",
1473         .init_fs_context        = hugetlbfs_init_fs_context,
1474         .parameters             = hugetlb_fs_parameters,
1475         .kill_sb                = kill_litter_super,
1476 };
1477
1478 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1479
1480 static int can_do_hugetlb_shm(void)
1481 {
1482         kgid_t shm_group;
1483         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1484         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1485 }
1486
1487 static int get_hstate_idx(int page_size_log)
1488 {
1489         struct hstate *h = hstate_sizelog(page_size_log);
1490
1491         if (!h)
1492                 return -1;
1493         return hstate_index(h);
1494 }
1495
1496 /*
1497  * Note that size should be aligned to proper hugepage size in caller side,
1498  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1499  */
1500 struct file *hugetlb_file_setup(const char *name, size_t size,
1501                                 vm_flags_t acctflag, int creat_flags,
1502                                 int page_size_log)
1503 {
1504         struct inode *inode;
1505         struct vfsmount *mnt;
1506         int hstate_idx;
1507         struct file *file;
1508
1509         hstate_idx = get_hstate_idx(page_size_log);
1510         if (hstate_idx < 0)
1511                 return ERR_PTR(-ENODEV);
1512
1513         mnt = hugetlbfs_vfsmount[hstate_idx];
1514         if (!mnt)
1515                 return ERR_PTR(-ENOENT);
1516
1517         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1518                 struct ucounts *ucounts = current_ucounts();
1519
1520                 if (user_shm_lock(size, ucounts)) {
1521                         pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is obsolete\n",
1522                                 current->comm, current->pid);
1523                         user_shm_unlock(size, ucounts);
1524                 }
1525                 return ERR_PTR(-EPERM);
1526         }
1527
1528         file = ERR_PTR(-ENOSPC);
1529         inode = hugetlbfs_get_inode(mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0);
1530         if (!inode)
1531                 goto out;
1532         if (creat_flags == HUGETLB_SHMFS_INODE)
1533                 inode->i_flags |= S_PRIVATE;
1534
1535         inode->i_size = size;
1536         clear_nlink(inode);
1537
1538         if (!hugetlb_reserve_pages(inode, 0,
1539                         size >> huge_page_shift(hstate_inode(inode)), NULL,
1540                         acctflag))
1541                 file = ERR_PTR(-ENOMEM);
1542         else
1543                 file = alloc_file_pseudo(inode, mnt, name, O_RDWR,
1544                                         &hugetlbfs_file_operations);
1545         if (!IS_ERR(file))
1546                 return file;
1547
1548         iput(inode);
1549 out:
1550         return file;
1551 }
1552
1553 static struct vfsmount *__init mount_one_hugetlbfs(struct hstate *h)
1554 {
1555         struct fs_context *fc;
1556         struct vfsmount *mnt;
1557
1558         fc = fs_context_for_mount(&hugetlbfs_fs_type, SB_KERNMOUNT);
1559         if (IS_ERR(fc)) {
1560                 mnt = ERR_CAST(fc);
1561         } else {
1562                 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1563                 ctx->hstate = h;
1564                 mnt = fc_mount(fc);
1565                 put_fs_context(fc);
1566         }
1567         if (IS_ERR(mnt))
1568                 pr_err("Cannot mount internal hugetlbfs for page size %luK",
1569                        huge_page_size(h) >> 10);
1570         return mnt;
1571 }
1572
1573 static int __init init_hugetlbfs_fs(void)
1574 {
1575         struct vfsmount *mnt;
1576         struct hstate *h;
1577         int error;
1578         int i;
1579
1580         if (!hugepages_supported()) {
1581                 pr_info("disabling because there are no supported hugepage sizes\n");
1582                 return -ENOTSUPP;
1583         }
1584
1585         error = -ENOMEM;
1586         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1587                                         sizeof(struct hugetlbfs_inode_info),
1588                                         0, SLAB_ACCOUNT, init_once);
1589         if (hugetlbfs_inode_cachep == NULL)
1590                 goto out;
1591
1592         error = register_filesystem(&hugetlbfs_fs_type);
1593         if (error)
1594                 goto out_free;
1595
1596         /* default hstate mount is required */
1597         mnt = mount_one_hugetlbfs(&default_hstate);
1598         if (IS_ERR(mnt)) {
1599                 error = PTR_ERR(mnt);
1600                 goto out_unreg;
1601         }
1602         hugetlbfs_vfsmount[default_hstate_idx] = mnt;
1603
1604         /* other hstates are optional */
1605         i = 0;
1606         for_each_hstate(h) {
1607                 if (i == default_hstate_idx) {
1608                         i++;
1609                         continue;
1610                 }
1611
1612                 mnt = mount_one_hugetlbfs(h);
1613                 if (IS_ERR(mnt))
1614                         hugetlbfs_vfsmount[i] = NULL;
1615                 else
1616                         hugetlbfs_vfsmount[i] = mnt;
1617                 i++;
1618         }
1619
1620         return 0;
1621
1622  out_unreg:
1623         (void)unregister_filesystem(&hugetlbfs_fs_type);
1624  out_free:
1625         kmem_cache_destroy(hugetlbfs_inode_cachep);
1626  out:
1627         return error;
1628 }
1629 fs_initcall(init_hugetlbfs_fs)