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 /*
 112  * Mask used when checking the page offset value passed in via system
 113  * calls.  This value will be converted to a loff_t which is signed.
 114  * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the
 115  * value.  The extra bit (- 1 in the shift value) is to take the sign
 116  * bit into account.
 117  */
 118 #define PGOFF_LOFFT_MAX \
 119         (((1UL << (PAGE_SHIFT + 1)) - 1) <<  (BITS_PER_LONG - (PAGE_SHIFT + 1)))
 120
 121 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 122 {
 123         struct inode *inode = file_inode(file);
 124         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 125         loff_t len, vma_len;
 126         int ret;
 127         struct hstate *h = hstate_file(file);
 128
 129         /*
 130          * vma address alignment (but not the pgoff alignment) has
 131          * already been checked by prepare_hugepage_range.  If you add
 132          * any error returns here, do so after setting VM_HUGETLB, so
 133          * is_vm_hugetlb_page tests below unmap_region go the right
 134          * way when do_mmap unwinds (may be important on powerpc
 135          * and ia64).
 136          */
 137         vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND;
 138         vma->vm_ops = &hugetlb_vm_ops;
 139
 140         ret = seal_check_future_write(info->seals, vma);
 141         if (ret)
 142                 return ret;
 143
 144         /*
 145          * page based offset in vm_pgoff could be sufficiently large to
 146          * overflow a loff_t when converted to byte offset.  This can
 147          * only happen on architectures where sizeof(loff_t) ==
 148          * sizeof(unsigned long).  So, only check in those instances.
 149          */
 150         if (sizeof(unsigned long) == sizeof(loff_t)) {
 151                 if (vma->vm_pgoff & PGOFF_LOFFT_MAX)
 152                         return -EINVAL;
 153         }
 154
 155         /* must be huge page aligned */
 156         if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
 157                 return -EINVAL;
 158
 159         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
 160         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 161         /* check for overflow */
 162         if (len < vma_len)
 163                 return -EINVAL;
 164
 165         inode_lock(inode);
 166         file_accessed(file);
 167
 168         ret = -ENOMEM;
 169         if (!hugetlb_reserve_pages(inode,
 170                                 vma->vm_pgoff >> huge_page_order(h),
 171                                 len >> huge_page_shift(h), vma,
 172                                 vma->vm_flags))
 173                 goto out;
 174
 175         ret = 0;
 176         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
 177                 i_size_write(inode, len);
 178 out:
 179         inode_unlock(inode);
 180
 181         return ret;
 182 }
 183
 184 /*
 185  * Called under mmap_write_lock(mm).
 186  */
 187
 188 static unsigned long
 189 hugetlb_get_unmapped_area_bottomup(struct file *file, unsigned long addr,
 190                 unsigned long len, unsigned long pgoff, unsigned long flags)
 191 {
 192         struct hstate *h = hstate_file(file);
 193         struct vm_unmapped_area_info info;
 194
 195         info.flags = 0;
 196         info.length = len;
 197         info.low_limit = current->mm->mmap_base;
 198         info.high_limit = arch_get_mmap_end(addr, len, flags);
 199         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 200         info.align_offset = 0;
 201         return vm_unmapped_area(&info);
 202 }
 203
 204 static unsigned long
 205 hugetlb_get_unmapped_area_topdown(struct file *file, unsigned long addr,
 206                 unsigned long len, unsigned long pgoff, unsigned long flags)
 207 {
 208         struct hstate *h = hstate_file(file);
 209         struct vm_unmapped_area_info info;
 210
 211         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 212         info.length = len;
 213         info.low_limit = max(PAGE_SIZE, mmap_min_addr);
 214         info.high_limit = arch_get_mmap_base(addr, current->mm->mmap_base);
 215         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 216         info.align_offset = 0;
 217         addr = vm_unmapped_area(&info);
 218
 219         /*
 220          * A failed mmap() very likely causes application failure,
 221          * so fall back to the bottom-up function here. This scenario
 222          * can happen with large stack limits and large mmap()
 223          * allocations.
 224          */
 225         if (unlikely(offset_in_page(addr))) {
 226                 VM_BUG_ON(addr != -ENOMEM);
 227                 info.flags = 0;
 228                 info.low_limit = current->mm->mmap_base;
 229                 info.high_limit = arch_get_mmap_end(addr, len, flags);
 230                 addr = vm_unmapped_area(&info);
 231         }
 232
 233         return addr;
 234 }
 235
 236 unsigned long
 237 generic_hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 238                                   unsigned long len, unsigned long pgoff,
 239                                   unsigned long flags)
 240 {
 241         struct mm_struct *mm = current->mm;
 242         struct vm_area_struct *vma;
 243         struct hstate *h = hstate_file(file);
 244         const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags);
 245
 246         if (len & ~huge_page_mask(h))
 247                 return -EINVAL;
 248         if (len > TASK_SIZE)
 249                 return -ENOMEM;
 250
 251         if (flags & MAP_FIXED) {
 252                 if (prepare_hugepage_range(file, addr, len))
 253                         return -EINVAL;
 254                 return addr;
 255         }
 256
 257         if (addr) {
 258                 addr = ALIGN(addr, huge_page_size(h));
 259                 vma = find_vma(mm, addr);
 260                 if (mmap_end - len >= addr &&
 261                     (!vma || addr + len <= vm_start_gap(vma)))
 262                         return addr;
 263         }
 264
 265         /*
 266          * Use mm->get_unmapped_area value as a hint to use topdown routine.
 267          * If architectures have special needs, they should define their own
 268          * version of hugetlb_get_unmapped_area.
 269          */
 270         if (mm->get_unmapped_area == arch_get_unmapped_area_topdown)
 271                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 272                                 pgoff, flags);
 273         return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 274                         pgoff, flags);
 275 }
 276
 277 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 278 static unsigned long
 279 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 280                           unsigned long len, unsigned long pgoff,
 281                           unsigned long flags)
 282 {
 283         return generic_hugetlb_get_unmapped_area(file, addr, len, pgoff, flags);
 284 }
 285 #endif
 286
 287 static size_t
 288 hugetlbfs_read_actor(struct page *page, unsigned long offset,
 289                         struct iov_iter *to, unsigned long size)
 290 {
 291         size_t copied = 0;
 292         int i, chunksize;
 293
 294         /* Find which 4k chunk and offset with in that chunk */
 295         i = offset >> PAGE_SHIFT;
 296         offset = offset & ~PAGE_MASK;
 297
 298         while (size) {
 299                 size_t n;
 300                 chunksize = PAGE_SIZE;
 301                 if (offset)
 302                         chunksize -= offset;
 303                 if (chunksize > size)
 304                         chunksize = size;
 305                 n = copy_page_to_iter(&page[i], offset, chunksize, to);
 306                 copied += n;
 307                 if (n != chunksize)
 308                         return copied;
 309                 offset = 0;
 310                 size -= chunksize;
 311                 i++;
 312         }
 313         return copied;
 314 }
 315
 316 /*
 317  * Support for read() - Find the page attached to f_mapping and copy out the
 318  * data. Its *very* similar to generic_file_buffered_read(), we can't use that
 319  * since it has PAGE_SIZE assumptions.
 320  */
 321 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
 322 {
 323         struct file *file = iocb->ki_filp;
 324         struct hstate *h = hstate_file(file);
 325         struct address_space *mapping = file->f_mapping;
 326         struct inode *inode = mapping->host;
 327         unsigned long index = iocb->ki_pos >> huge_page_shift(h);
 328         unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
 329         unsigned long end_index;
 330         loff_t isize;
 331         ssize_t retval = 0;
 332
 333         while (iov_iter_count(to)) {
 334                 struct page *page;
 335                 size_t nr, copied;
 336
 337                 /* nr is the maximum number of bytes to copy from this page */
 338                 nr = huge_page_size(h);
 339                 isize = i_size_read(inode);
 340                 if (!isize)
 341                         break;
 342                 end_index = (isize - 1) >> huge_page_shift(h);
 343                 if (index > end_index)
 344                         break;
 345                 if (index == end_index) {
 346                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
 347                         if (nr <= offset)
 348                                 break;
 349                 }
 350                 nr = nr - offset;
 351
 352                 /* Find the page */
 353                 page = find_lock_page(mapping, index);
 354                 if (unlikely(page == NULL)) {
 355                         /*
 356                          * We have a HOLE, zero out the user-buffer for the
 357                          * length of the hole or request.
 358                          */
 359                         copied = iov_iter_zero(nr, to);
 360                 } else {
 361                         unlock_page(page);
 362
 363                         /*
 364                          * We have the page, copy it to user space buffer.
 365                          */
 366                         copied = hugetlbfs_read_actor(page, offset, to, nr);
 367                         put_page(page);
 368                 }
 369                 offset += copied;
 370                 retval += copied;
 371                 if (copied != nr && iov_iter_count(to)) {
 372                         if (!retval)
 373                                 retval = -EFAULT;
 374                         break;
 375                 }
 376                 index += offset >> huge_page_shift(h);
 377                 offset &= ~huge_page_mask(h);
 378         }
 379         iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
 380         return retval;
 381 }
 382
 383 static int hugetlbfs_write_begin(struct file *file,
 384                         struct address_space *mapping,
 385                         loff_t pos, unsigned len,
 386                         struct page **pagep, void **fsdata)
 387 {
 388         return -EINVAL;
 389 }
 390
 391 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
 392                         loff_t pos, unsigned len, unsigned copied,
 393                         struct page *page, void *fsdata)
 394 {
 395         BUG();
 396         return -EINVAL;
 397 }
 398
 399 static void remove_huge_page(struct page *page)
 400 {
 401         ClearPageDirty(page);
 402         ClearPageUptodate(page);
 403         delete_from_page_cache(page);
 404 }
 405
 406 static void
 407 hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end,
 408                       zap_flags_t zap_flags)
 409 {
 410         struct vm_area_struct *vma;
 411
 412         /*
 413          * end == 0 indicates that the entire range after start should be
 414          * unmapped.  Note, end is exclusive, whereas the interval tree takes
 415          * an inclusive "last".
 416          */
 417         vma_interval_tree_foreach(vma, root, start, end ? end - 1 : ULONG_MAX) {
 418                 unsigned long v_offset;
 419                 unsigned long v_end;
 420
 421                 /*
 422                  * Can the expression below overflow on 32-bit arches?
 423                  * No, because the interval tree returns us only those vmas
 424                  * which overlap the truncated area starting at pgoff,
 425                  * and no vma on a 32-bit arch can span beyond the 4GB.
 426                  */
 427                 if (vma->vm_pgoff < start)
 428                         v_offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
 429                 else
 430                         v_offset = 0;
 431
 432                 if (!end)
 433                         v_end = vma->vm_end;
 434                 else {
 435                         v_end = ((end - vma->vm_pgoff) << PAGE_SHIFT)
 436                                                         + vma->vm_start;
 437                         if (v_end > vma->vm_end)
 438                                 v_end = vma->vm_end;
 439                 }
 440
 441                 unmap_hugepage_range(vma, vma->vm_start + v_offset, v_end,
 442                                      NULL, zap_flags);
 443         }
 444 }
 445
 446 /*
 447  * remove_inode_hugepages handles two distinct cases: truncation and hole
 448  * punch.  There are subtle differences in operation for each case.
 449  *
 450  * truncation is indicated by end of range being LLONG_MAX
 451  *      In this case, we first scan the range and release found pages.
 452  *      After releasing pages, hugetlb_unreserve_pages cleans up region/reserve
 453  *      maps and global counts.  Page faults can not race with truncation
 454  *      in this routine.  hugetlb_no_page() holds i_mmap_rwsem and prevents
 455  *      page faults in the truncated range by checking i_size.  i_size is
 456  *      modified while holding i_mmap_rwsem.
 457  * hole punch is indicated if end is not LLONG_MAX
 458  *      In the hole punch case we scan the range and release found pages.
 459  *      Only when releasing a page is the associated region/reserve map
 460  *      deleted.  The region/reserve map for ranges without associated
 461  *      pages are not modified.  Page faults can race with hole punch.
 462  *      This is indicated if we find a mapped page.
 463  * Note: If the passed end of range value is beyond the end of file, but
 464  * not LLONG_MAX this routine still performs a hole punch operation.
 465  */
 466 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 467                                    loff_t lend)
 468 {
 469         struct hstate *h = hstate_inode(inode);
 470         struct address_space *mapping = &inode->i_data;
 471         const pgoff_t start = lstart >> huge_page_shift(h);
 472         const pgoff_t end = lend >> huge_page_shift(h);
 473         struct folio_batch fbatch;
 474         pgoff_t next, index;
 475         int i, freed = 0;
 476         bool truncate_op = (lend == LLONG_MAX);
 477
 478         folio_batch_init(&fbatch);
 479         next = start;
 480         while (filemap_get_folios(mapping, &next, end - 1, &fbatch)) {
 481                 for (i = 0; i < folio_batch_count(&fbatch); ++i) {
 482                         struct folio *folio = fbatch.folios[i];
 483                         u32 hash = 0;
 484
 485                         index = folio->index;
 486                         if (!truncate_op) {
 487                                 /*
 488                                  * Only need to hold the fault mutex in the
 489                                  * hole punch case.  This prevents races with
 490                                  * page faults.  Races are not possible in the
 491                                  * case of truncation.
 492                                  */
 493                                 hash = hugetlb_fault_mutex_hash(mapping, index);
 494                                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
 495                         }
 496
 497                         /*
 498                          * If folio is mapped, it was faulted in after being
 499                          * unmapped in caller.  Unmap (again) now after taking
 500                          * the fault mutex.  The mutex will prevent faults
 501                          * until we finish removing the folio.
 502                          *
 503                          * This race can only happen in the hole punch case.
 504                          * Getting here in a truncate operation is a bug.
 505                          */
 506                         if (unlikely(folio_mapped(folio))) {
 507                                 BUG_ON(truncate_op);
 508
 509                                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 510                                 i_mmap_lock_write(mapping);
 511                                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
 512                                 hugetlb_vmdelete_list(&mapping->i_mmap,
 513                                         index * pages_per_huge_page(h),
 514                                         (index + 1) * pages_per_huge_page(h),
 515                                         ZAP_FLAG_DROP_MARKER);
 516                                 i_mmap_unlock_write(mapping);
 517                         }
 518
 519                         folio_lock(folio);
 520                         /*
 521                          * We must free the huge page and remove from page
 522                          * cache (remove_huge_page) BEFORE removing the
 523                          * region/reserve map (hugetlb_unreserve_pages).  In
 524                          * rare out of memory conditions, removal of the
 525                          * region/reserve map could fail. Correspondingly,
 526                          * the subpool and global reserve usage count can need
 527                          * to be adjusted.
 528                          */
 529                         VM_BUG_ON(HPageRestoreReserve(&folio->page));
 530                         remove_huge_page(&folio->page);
 531                         freed++;
 532                         if (!truncate_op) {
 533                                 if (unlikely(hugetlb_unreserve_pages(inode,
 534                                                         index, index + 1, 1)))
 535                                         hugetlb_fix_reserve_counts(inode);
 536                         }
 537
 538                         folio_unlock(folio);
 539                         if (!truncate_op)
 540                                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 541                 }
 542                 folio_batch_release(&fbatch);
 543                 cond_resched();
 544         }
 545
 546         if (truncate_op)
 547                 (void)hugetlb_unreserve_pages(inode, start, LONG_MAX, freed);
 548 }
 549
 550 static void hugetlbfs_evict_inode(struct inode *inode)
 551 {
 552         struct resv_map *resv_map;
 553
 554         remove_inode_hugepages(inode, 0, LLONG_MAX);
 555
 556         /*
 557          * Get the resv_map from the address space embedded in the inode.
 558          * This is the address space which points to any resv_map allocated
 559          * at inode creation time.  If this is a device special inode,
 560          * i_mapping may not point to the original address space.
 561          */
 562         resv_map = (struct resv_map *)(&inode->i_data)->private_data;
 563         /* Only regular and link inodes have associated reserve maps */
 564         if (resv_map)
 565                 resv_map_release(&resv_map->refs);
 566         clear_inode(inode);
 567 }
 568
 569 static void hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 570 {
 571         pgoff_t pgoff;
 572         struct address_space *mapping = inode->i_mapping;
 573         struct hstate *h = hstate_inode(inode);
 574
 575         BUG_ON(offset & ~huge_page_mask(h));
 576         pgoff = offset >> PAGE_SHIFT;
 577
 578         i_mmap_lock_write(mapping);
 579         i_size_write(inode, offset);
 580         if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
 581                 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0,
 582                                       ZAP_FLAG_DROP_MARKER);
 583         i_mmap_unlock_write(mapping);
 584         remove_inode_hugepages(inode, offset, LLONG_MAX);
 585 }
 586
 587 static void hugetlbfs_zero_partial_page(struct hstate *h,
 588                                         struct address_space *mapping,
 589                                         loff_t start,
 590                                         loff_t end)
 591 {
 592         pgoff_t idx = start >> huge_page_shift(h);
 593         struct folio *folio;
 594
 595         folio = filemap_lock_folio(mapping, idx);
 596         if (!folio)
 597                 return;
 598
 599         start = start & ~huge_page_mask(h);
 600         end = end & ~huge_page_mask(h);
 601         if (!end)
 602                 end = huge_page_size(h);
 603
 604         folio_zero_segment(folio, (size_t)start, (size_t)end);
 605
 606         folio_unlock(folio);
 607         folio_put(folio);
 608 }
 609
 610 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
 611 {
 612         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 613         struct address_space *mapping = inode->i_mapping;
 614         struct hstate *h = hstate_inode(inode);
 615         loff_t hpage_size = huge_page_size(h);
 616         loff_t hole_start, hole_end;
 617
 618         /*
 619          * hole_start and hole_end indicate the full pages within the hole.
 620          */
 621         hole_start = round_up(offset, hpage_size);
 622         hole_end = round_down(offset + len, hpage_size);
 623
 624         inode_lock(inode);
 625
 626         /* protected by i_rwsem */
 627         if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) {
 628                 inode_unlock(inode);
 629                 return -EPERM;
 630         }
 631
 632         i_mmap_lock_write(mapping);
 633
 634         /* If range starts before first full page, zero partial page. */
 635         if (offset < hole_start)
 636                 hugetlbfs_zero_partial_page(h, mapping,
 637                                 offset, min(offset + len, hole_start));
 638
 639         /* Unmap users of full pages in the hole. */
 640         if (hole_end > hole_start) {
 641                 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
 642                         hugetlb_vmdelete_list(&mapping->i_mmap,
 643                                               hole_start >> PAGE_SHIFT,
 644                                               hole_end >> PAGE_SHIFT, 0);
 645         }
 646
 647         /* If range extends beyond last full page, zero partial page. */
 648         if ((offset + len) > hole_end && (offset + len) > hole_start)
 649                 hugetlbfs_zero_partial_page(h, mapping,
 650                                 hole_end, offset + len);
 651
 652         i_mmap_unlock_write(mapping);
 653
 654         /* Remove full pages from the file. */
 655         if (hole_end > hole_start)
 656                 remove_inode_hugepages(inode, hole_start, hole_end);
 657
 658         inode_unlock(inode);
 659
 660         return 0;
 661 }
 662
 663 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
 664                                 loff_t len)
 665 {
 666         struct inode *inode = file_inode(file);
 667         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 668         struct address_space *mapping = inode->i_mapping;
 669         struct hstate *h = hstate_inode(inode);
 670         struct vm_area_struct pseudo_vma;
 671         struct mm_struct *mm = current->mm;
 672         loff_t hpage_size = huge_page_size(h);
 673         unsigned long hpage_shift = huge_page_shift(h);
 674         pgoff_t start, index, end;
 675         int error;
 676         u32 hash;
 677
 678         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
 679                 return -EOPNOTSUPP;
 680
 681         if (mode & FALLOC_FL_PUNCH_HOLE)
 682                 return hugetlbfs_punch_hole(inode, offset, len);
 683
 684         /*
 685          * Default preallocate case.
 686          * For this range, start is rounded down and end is rounded up
 687          * as well as being converted to page offsets.
 688          */
 689         start = offset >> hpage_shift;
 690         end = (offset + len + hpage_size - 1) >> hpage_shift;
 691
 692         inode_lock(inode);
 693
 694         /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
 695         error = inode_newsize_ok(inode, offset + len);
 696         if (error)
 697                 goto out;
 698
 699         if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) {
 700                 error = -EPERM;
 701                 goto out;
 702         }
 703
 704         /*
 705          * Initialize a pseudo vma as this is required by the huge page
 706          * allocation routines.  If NUMA is configured, use page index
 707          * as input to create an allocation policy.
 708          */
 709         vma_init(&pseudo_vma, mm);
 710         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
 711         pseudo_vma.vm_file = file;
 712
 713         for (index = start; index < end; index++) {
 714                 /*
 715                  * This is supposed to be the vaddr where the page is being
 716                  * faulted in, but we have no vaddr here.
 717                  */
 718                 struct page *page;
 719                 unsigned long addr;
 720
 721                 cond_resched();
 722
 723                 /*
 724                  * fallocate(2) manpage permits EINTR; we may have been
 725                  * interrupted because we are using up too much memory.
 726                  */
 727                 if (signal_pending(current)) {
 728                         error = -EINTR;
 729                         break;
 730                 }
 731
 732                 /* Set numa allocation policy based on index */
 733                 hugetlb_set_vma_policy(&pseudo_vma, inode, index);
 734
 735                 /* addr is the offset within the file (zero based) */
 736                 addr = index * hpage_size;
 737
 738                 /*
 739                  * fault mutex taken here, protects against fault path
 740                  * and hole punch.  inode_lock previously taken protects
 741                  * against truncation.
 742                  */
 743                 hash = hugetlb_fault_mutex_hash(mapping, index);
 744                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
 745
 746                 /* See if already present in mapping to avoid alloc/free */
 747                 page = find_get_page(mapping, index);
 748                 if (page) {
 749                         put_page(page);
 750                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 751                         hugetlb_drop_vma_policy(&pseudo_vma);
 752                         continue;
 753                 }
 754
 755                 /*
 756                  * Allocate page without setting the avoid_reserve argument.
 757                  * There certainly are no reserves associated with the
 758                  * pseudo_vma.  However, there could be shared mappings with
 759                  * reserves for the file at the inode level.  If we fallocate
 760                  * pages in these areas, we need to consume the reserves
 761                  * to keep reservation accounting consistent.
 762                  */
 763                 page = alloc_huge_page(&pseudo_vma, addr, 0);
 764                 hugetlb_drop_vma_policy(&pseudo_vma);
 765                 if (IS_ERR(page)) {
 766                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 767                         error = PTR_ERR(page);
 768                         goto out;
 769                 }
 770                 clear_huge_page(page, addr, pages_per_huge_page(h));
 771                 __SetPageUptodate(page);
 772                 error = huge_add_to_page_cache(page, mapping, index);
 773                 if (unlikely(error)) {
 774                         restore_reserve_on_error(h, &pseudo_vma, addr, page);
 775                         put_page(page);
 776                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 777                         goto out;
 778                 }
 779
 780                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 781
 782                 SetHPageMigratable(page);
 783                 /*
 784                  * unlock_page because locked by huge_add_to_page_cache()
 785                  * put_page() due to reference from alloc_huge_page()
 786                  */
 787                 unlock_page(page);
 788                 put_page(page);
 789         }
 790
 791         if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
 792                 i_size_write(inode, offset + len);
 793         inode->i_ctime = current_time(inode);
 794 out:
 795         inode_unlock(inode);
 796         return error;
 797 }
 798
 799 static int hugetlbfs_setattr(struct user_namespace *mnt_userns,
 800                              struct dentry *dentry, struct iattr *attr)
 801 {
 802         struct inode *inode = d_inode(dentry);
 803         struct hstate *h = hstate_inode(inode);
 804         int error;
 805         unsigned int ia_valid = attr->ia_valid;
 806         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 807
 808         error = setattr_prepare(&init_user_ns, dentry, attr);
 809         if (error)
 810                 return error;
 811
 812         if (ia_valid & ATTR_SIZE) {
 813                 loff_t oldsize = inode->i_size;
 814                 loff_t newsize = attr->ia_size;
 815
 816                 if (newsize & ~huge_page_mask(h))
 817                         return -EINVAL;
 818                 /* protected by i_rwsem */
 819                 if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
 820                     (newsize > oldsize && (info->seals & F_SEAL_GROW)))
 821                         return -EPERM;
 822                 hugetlb_vmtruncate(inode, newsize);
 823         }
 824
 825         setattr_copy(&init_user_ns, inode, attr);
 826         mark_inode_dirty(inode);
 827         return 0;
 828 }
 829
 830 static struct inode *hugetlbfs_get_root(struct super_block *sb,
 831                                         struct hugetlbfs_fs_context *ctx)
 832 {
 833         struct inode *inode;
 834
 835         inode = new_inode(sb);
 836         if (inode) {
 837                 inode->i_ino = get_next_ino();
 838                 inode->i_mode = S_IFDIR | ctx->mode;
 839                 inode->i_uid = ctx->uid;
 840                 inode->i_gid = ctx->gid;
 841                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 842                 inode->i_op = &hugetlbfs_dir_inode_operations;
 843                 inode->i_fop = &simple_dir_operations;
 844                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
 845                 inc_nlink(inode);
 846                 lockdep_annotate_inode_mutex_key(inode);
 847         }
 848         return inode;
 849 }
 850
 851 /*
 852  * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
 853  * be taken from reclaim -- unlike regular filesystems. This needs an
 854  * annotation because huge_pmd_share() does an allocation under hugetlb's
 855  * i_mmap_rwsem.
 856  */
 857 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
 858
 859 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 860                                         struct inode *dir,
 861                                         umode_t mode, dev_t dev)
 862 {
 863         struct inode *inode;
 864         struct resv_map *resv_map = NULL;
 865
 866         /*
 867          * Reserve maps are only needed for inodes that can have associated
 868          * page allocations.
 869          */
 870         if (S_ISREG(mode) || S_ISLNK(mode)) {
 871                 resv_map = resv_map_alloc();
 872                 if (!resv_map)
 873                         return NULL;
 874         }
 875
 876         inode = new_inode(sb);
 877         if (inode) {
 878                 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 879
 880                 inode->i_ino = get_next_ino();
 881                 inode_init_owner(&init_user_ns, inode, dir, mode);
 882                 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
 883                                 &hugetlbfs_i_mmap_rwsem_key);
 884                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 885                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 886                 inode->i_mapping->private_data = resv_map;
 887                 info->seals = F_SEAL_SEAL;
 888                 switch (mode & S_IFMT) {
 889                 default:
 890                         init_special_inode(inode, mode, dev);
 891                         break;
 892                 case S_IFREG:
 893                         inode->i_op = &hugetlbfs_inode_operations;
 894                         inode->i_fop = &hugetlbfs_file_operations;
 895                         break;
 896                 case S_IFDIR:
 897                         inode->i_op = &hugetlbfs_dir_inode_operations;
 898                         inode->i_fop = &simple_dir_operations;
 899
 900                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 901                         inc_nlink(inode);
 902                         break;
 903                 case S_IFLNK:
 904                         inode->i_op = &page_symlink_inode_operations;
 905                         inode_nohighmem(inode);
 906                         break;
 907                 }
 908                 lockdep_annotate_inode_mutex_key(inode);
 909         } else {
 910                 if (resv_map)
 911                         kref_put(&resv_map->refs, resv_map_release);
 912         }
 913
 914         return inode;
 915 }
 916
 917 /*
 918  * File creation. Allocate an inode, and we're done..
 919  */
 920 static int do_hugetlbfs_mknod(struct inode *dir,
 921                         struct dentry *dentry,
 922                         umode_t mode,
 923                         dev_t dev,
 924                         bool tmpfile)
 925 {
 926         struct inode *inode;
 927         int error = -ENOSPC;
 928
 929         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
 930         if (inode) {
 931                 dir->i_ctime = dir->i_mtime = current_time(dir);
 932                 if (tmpfile) {
 933                         d_tmpfile(dentry, inode);
 934                 } else {
 935                         d_instantiate(dentry, inode);
 936                         dget(dentry);/* Extra count - pin the dentry in core */
 937                 }
 938                 error = 0;
 939         }
 940         return error;
 941 }
 942
 943 static int hugetlbfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
 944                            struct dentry *dentry, umode_t mode, dev_t dev)
 945 {
 946         return do_hugetlbfs_mknod(dir, dentry, mode, dev, false);
 947 }
 948
 949 static int hugetlbfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
 950                            struct dentry *dentry, umode_t mode)
 951 {
 952         int retval = hugetlbfs_mknod(&init_user_ns, dir, dentry,
 953                                      mode | S_IFDIR, 0);
 954         if (!retval)
 955                 inc_nlink(dir);
 956         return retval;
 957 }
 958
 959 static int hugetlbfs_create(struct user_namespace *mnt_userns,
 960                             struct inode *dir, struct dentry *dentry,
 961                             umode_t mode, bool excl)
 962 {
 963         return hugetlbfs_mknod(&init_user_ns, dir, dentry, mode | S_IFREG, 0);
 964 }
 965
 966 static int hugetlbfs_tmpfile(struct user_namespace *mnt_userns,
 967                              struct inode *dir, struct dentry *dentry,
 968                              umode_t mode)
 969 {
 970         return do_hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0, true);
 971 }
 972
 973 static int hugetlbfs_symlink(struct user_namespace *mnt_userns,
 974                              struct inode *dir, struct dentry *dentry,
 975                              const char *symname)
 976 {
 977         struct inode *inode;
 978         int error = -ENOSPC;
 979
 980         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
 981         if (inode) {
 982                 int l = strlen(symname)+1;
 983                 error = page_symlink(inode, symname, l);
 984                 if (!error) {
 985                         d_instantiate(dentry, inode);
 986                         dget(dentry);
 987                 } else
 988                         iput(inode);
 989         }
 990         dir->i_ctime = dir->i_mtime = current_time(dir);
 991
 992         return error;
 993 }
 994
 995 #ifdef CONFIG_MIGRATION
 996 static int hugetlbfs_migrate_folio(struct address_space *mapping,
 997                                 struct folio *dst, struct folio *src,
 998                                 enum migrate_mode mode)
 999 {
1000         int rc;
1001
1002         rc = migrate_huge_page_move_mapping(mapping, dst, src);
1003         if (rc != MIGRATEPAGE_SUCCESS)
1004                 return rc;
1005
1006         if (hugetlb_page_subpool(&src->page)) {
1007                 hugetlb_set_page_subpool(&dst->page,
1008                                         hugetlb_page_subpool(&src->page));
1009                 hugetlb_set_page_subpool(&src->page, NULL);
1010         }
1011
1012         if (mode != MIGRATE_SYNC_NO_COPY)
1013                 folio_migrate_copy(dst, src);
1014         else
1015                 folio_migrate_flags(dst, src);
1016
1017         return MIGRATEPAGE_SUCCESS;
1018 }
1019 #else
1020 #define hugetlbfs_migrate_folio NULL
1021 #endif
1022
1023 static int hugetlbfs_error_remove_page(struct address_space *mapping,
1024                                 struct page *page)
1025 {
1026         struct inode *inode = mapping->host;
1027         pgoff_t index = page->index;
1028
1029         remove_huge_page(page);
1030         if (unlikely(hugetlb_unreserve_pages(inode, index, index + 1, 1)))
1031                 hugetlb_fix_reserve_counts(inode);
1032
1033         return 0;
1034 }
1035
1036 /*
1037  * Display the mount options in /proc/mounts.
1038  */
1039 static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root)
1040 {
1041         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(root->d_sb);
1042         struct hugepage_subpool *spool = sbinfo->spool;
1043         unsigned long hpage_size = huge_page_size(sbinfo->hstate);
1044         unsigned hpage_shift = huge_page_shift(sbinfo->hstate);
1045         char mod;
1046
1047         if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
1048                 seq_printf(m, ",uid=%u",
1049                            from_kuid_munged(&init_user_ns, sbinfo->uid));
1050         if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
1051                 seq_printf(m, ",gid=%u",
1052                            from_kgid_munged(&init_user_ns, sbinfo->gid));
1053         if (sbinfo->mode != 0755)
1054                 seq_printf(m, ",mode=%o", sbinfo->mode);
1055         if (sbinfo->max_inodes != -1)
1056                 seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes);
1057
1058         hpage_size /= 1024;
1059         mod = 'K';
1060         if (hpage_size >= 1024) {
1061                 hpage_size /= 1024;
1062                 mod = 'M';
1063         }
1064         seq_printf(m, ",pagesize=%lu%c", hpage_size, mod);
1065         if (spool) {
1066                 if (spool->max_hpages != -1)
1067                         seq_printf(m, ",size=%llu",
1068                                    (unsigned long long)spool->max_hpages << hpage_shift);
1069                 if (spool->min_hpages != -1)
1070                         seq_printf(m, ",min_size=%llu",
1071                                    (unsigned long long)spool->min_hpages << hpage_shift);
1072         }
1073         return 0;
1074 }
1075
1076 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1077 {
1078         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
1079         struct hstate *h = hstate_inode(d_inode(dentry));
1080
1081         buf->f_type = HUGETLBFS_MAGIC;
1082         buf->f_bsize = huge_page_size(h);
1083         if (sbinfo) {
1084                 spin_lock(&sbinfo->stat_lock);
1085                 /* If no limits set, just report 0 for max/free/used
1086                  * blocks, like simple_statfs() */
1087                 if (sbinfo->spool) {
1088                         long free_pages;
1089
1090                         spin_lock_irq(&sbinfo->spool->lock);
1091                         buf->f_blocks = sbinfo->spool->max_hpages;
1092                         free_pages = sbinfo->spool->max_hpages
1093                                 - sbinfo->spool->used_hpages;
1094                         buf->f_bavail = buf->f_bfree = free_pages;
1095                         spin_unlock_irq(&sbinfo->spool->lock);
1096                         buf->f_files = sbinfo->max_inodes;
1097                         buf->f_ffree = sbinfo->free_inodes;
1098                 }
1099                 spin_unlock(&sbinfo->stat_lock);
1100         }
1101         buf->f_namelen = NAME_MAX;
1102         return 0;
1103 }
1104
1105 static void hugetlbfs_put_super(struct super_block *sb)
1106 {
1107         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
1108
1109         if (sbi) {
1110                 sb->s_fs_info = NULL;
1111
1112                 if (sbi->spool)
1113                         hugepage_put_subpool(sbi->spool);
1114
1115                 kfree(sbi);
1116         }
1117 }
1118
1119 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1120 {
1121         if (sbinfo->free_inodes >= 0) {
1122                 spin_lock(&sbinfo->stat_lock);
1123                 if (unlikely(!sbinfo->free_inodes)) {
1124                         spin_unlock(&sbinfo->stat_lock);
1125                         return 0;
1126                 }
1127                 sbinfo->free_inodes--;
1128                 spin_unlock(&sbinfo->stat_lock);
1129         }
1130
1131         return 1;
1132 }
1133
1134 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1135 {
1136         if (sbinfo->free_inodes >= 0) {
1137                 spin_lock(&sbinfo->stat_lock);
1138                 sbinfo->free_inodes++;
1139                 spin_unlock(&sbinfo->stat_lock);
1140         }
1141 }
1142
1143
1144 static struct kmem_cache *hugetlbfs_inode_cachep;
1145
1146 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
1147 {
1148         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
1149         struct hugetlbfs_inode_info *p;
1150
1151         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
1152                 return NULL;
1153         p = alloc_inode_sb(sb, hugetlbfs_inode_cachep, GFP_KERNEL);
1154         if (unlikely(!p)) {
1155                 hugetlbfs_inc_free_inodes(sbinfo);
1156                 return NULL;
1157         }
1158
1159         /*
1160          * Any time after allocation, hugetlbfs_destroy_inode can be called
1161          * for the inode.  mpol_free_shared_policy is unconditionally called
1162          * as part of hugetlbfs_destroy_inode.  So, initialize policy here
1163          * in case of a quick call to destroy.
1164          *
1165          * Note that the policy is initialized even if we are creating a
1166          * private inode.  This simplifies hugetlbfs_destroy_inode.
1167          */
1168         mpol_shared_policy_init(&p->policy, NULL);
1169
1170         return &p->vfs_inode;
1171 }
1172
1173 static void hugetlbfs_free_inode(struct inode *inode)
1174 {
1175         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
1176 }
1177
1178 static void hugetlbfs_destroy_inode(struct inode *inode)
1179 {
1180         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
1181         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
1182 }
1183
1184 static const struct address_space_operations hugetlbfs_aops = {
1185         .write_begin    = hugetlbfs_write_begin,
1186         .write_end      = hugetlbfs_write_end,
1187         .dirty_folio    = noop_dirty_folio,
1188         .migrate_folio  = hugetlbfs_migrate_folio,
1189         .error_remove_page      = hugetlbfs_error_remove_page,
1190 };
1191
1192
1193 static void init_once(void *foo)
1194 {
1195         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
1196
1197         inode_init_once(&ei->vfs_inode);
1198 }
1199
1200 const struct file_operations hugetlbfs_file_operations = {
1201         .read_iter              = hugetlbfs_read_iter,
1202         .mmap                   = hugetlbfs_file_mmap,
1203         .fsync                  = noop_fsync,
1204         .get_unmapped_area      = hugetlb_get_unmapped_area,
1205         .llseek                 = default_llseek,
1206         .fallocate              = hugetlbfs_fallocate,
1207 };
1208
1209 static const struct inode_operations hugetlbfs_dir_inode_operations = {
1210         .create         = hugetlbfs_create,
1211         .lookup         = simple_lookup,
1212         .link           = simple_link,
1213         .unlink         = simple_unlink,
1214         .symlink        = hugetlbfs_symlink,
1215         .mkdir          = hugetlbfs_mkdir,
1216         .rmdir          = simple_rmdir,
1217         .mknod          = hugetlbfs_mknod,
1218         .rename         = simple_rename,
1219         .setattr        = hugetlbfs_setattr,
1220         .tmpfile        = hugetlbfs_tmpfile,
1221 };
1222
1223 static const struct inode_operations hugetlbfs_inode_operations = {
1224         .setattr        = hugetlbfs_setattr,
1225 };
1226
1227 static const struct super_operations hugetlbfs_ops = {
1228         .alloc_inode    = hugetlbfs_alloc_inode,
1229         .free_inode     = hugetlbfs_free_inode,
1230         .destroy_inode  = hugetlbfs_destroy_inode,
1231         .evict_inode    = hugetlbfs_evict_inode,
1232         .statfs         = hugetlbfs_statfs,
1233         .put_super      = hugetlbfs_put_super,
1234         .show_options   = hugetlbfs_show_options,
1235 };
1236
1237 /*
1238  * Convert size option passed from command line to number of huge pages
1239  * in the pool specified by hstate.  Size option could be in bytes
1240  * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1241  */
1242 static long
1243 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1244                          enum hugetlbfs_size_type val_type)
1245 {
1246         if (val_type == NO_SIZE)
1247                 return -1;
1248
1249         if (val_type == SIZE_PERCENT) {
1250                 size_opt <<= huge_page_shift(h);
1251                 size_opt *= h->max_huge_pages;
1252                 do_div(size_opt, 100);
1253         }
1254
1255         size_opt >>= huge_page_shift(h);
1256         return size_opt;
1257 }
1258
1259 /*
1260  * Parse one mount parameter.
1261  */
1262 static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1263 {
1264         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1265         struct fs_parse_result result;
1266         char *rest;
1267         unsigned long ps;
1268         int opt;
1269
1270         opt = fs_parse(fc, hugetlb_fs_parameters, param, &result);
1271         if (opt < 0)
1272                 return opt;
1273
1274         switch (opt) {
1275         case Opt_uid:
1276                 ctx->uid = make_kuid(current_user_ns(), result.uint_32);
1277                 if (!uid_valid(ctx->uid))
1278                         goto bad_val;
1279                 return 0;
1280
1281         case Opt_gid:
1282                 ctx->gid = make_kgid(current_user_ns(), result.uint_32);
1283                 if (!gid_valid(ctx->gid))
1284                         goto bad_val;
1285                 return 0;
1286
1287         case Opt_mode:
1288                 ctx->mode = result.uint_32 & 01777U;
1289                 return 0;
1290
1291         case Opt_size:
1292                 /* memparse() will accept a K/M/G without a digit */
1293                 if (!isdigit(param->string[0]))
1294                         goto bad_val;
1295                 ctx->max_size_opt = memparse(param->string, &rest);
1296                 ctx->max_val_type = SIZE_STD;
1297                 if (*rest == '%')
1298                         ctx->max_val_type = SIZE_PERCENT;
1299                 return 0;
1300
1301         case Opt_nr_inodes:
1302                 /* memparse() will accept a K/M/G without a digit */
1303                 if (!isdigit(param->string[0]))
1304                         goto bad_val;
1305                 ctx->nr_inodes = memparse(param->string, &rest);
1306                 return 0;
1307
1308         case Opt_pagesize:
1309                 ps = memparse(param->string, &rest);
1310                 ctx->hstate = size_to_hstate(ps);
1311                 if (!ctx->hstate) {
1312                         pr_err("Unsupported page size %lu MB\n", ps >> 20);
1313                         return -EINVAL;
1314                 }
1315                 return 0;
1316
1317         case Opt_min_size:
1318                 /* memparse() will accept a K/M/G without a digit */
1319                 if (!isdigit(param->string[0]))
1320                         goto bad_val;
1321                 ctx->min_size_opt = memparse(param->string, &rest);
1322                 ctx->min_val_type = SIZE_STD;
1323                 if (*rest == '%')
1324                         ctx->min_val_type = SIZE_PERCENT;
1325                 return 0;
1326
1327         default:
1328                 return -EINVAL;
1329         }
1330
1331 bad_val:
1332         return invalfc(fc, "Bad value '%s' for mount option '%s'\n",
1333                       param->string, param->key);
1334 }
1335
1336 /*
1337  * Validate the parsed options.
1338  */
1339 static int hugetlbfs_validate(struct fs_context *fc)
1340 {
1341         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1342
1343         /*
1344          * Use huge page pool size (in hstate) to convert the size
1345          * options to number of huge pages.  If NO_SIZE, -1 is returned.
1346          */
1347         ctx->max_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1348                                                    ctx->max_size_opt,
1349                                                    ctx->max_val_type);
1350         ctx->min_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1351                                                    ctx->min_size_opt,
1352                                                    ctx->min_val_type);
1353
1354         /*
1355          * If max_size was specified, then min_size must be smaller
1356          */
1357         if (ctx->max_val_type > NO_SIZE &&
1358             ctx->min_hpages > ctx->max_hpages) {
1359                 pr_err("Minimum size can not be greater than maximum size\n");
1360                 return -EINVAL;
1361         }
1362
1363         return 0;
1364 }
1365
1366 static int
1367 hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc)
1368 {
1369         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1370         struct hugetlbfs_sb_info *sbinfo;
1371
1372         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1373         if (!sbinfo)
1374                 return -ENOMEM;
1375         sb->s_fs_info = sbinfo;
1376         spin_lock_init(&sbinfo->stat_lock);
1377         sbinfo->hstate          = ctx->hstate;
1378         sbinfo->max_inodes      = ctx->nr_inodes;
1379         sbinfo->free_inodes     = ctx->nr_inodes;
1380         sbinfo->spool           = NULL;
1381         sbinfo->uid             = ctx->uid;
1382         sbinfo->gid             = ctx->gid;
1383         sbinfo->mode            = ctx->mode;
1384
1385         /*
1386          * Allocate and initialize subpool if maximum or minimum size is
1387          * specified.  Any needed reservations (for minimum size) are taken
1388          * taken when the subpool is created.
1389          */
1390         if (ctx->max_hpages != -1 || ctx->min_hpages != -1) {
1391                 sbinfo->spool = hugepage_new_subpool(ctx->hstate,
1392                                                      ctx->max_hpages,
1393                                                      ctx->min_hpages);
1394                 if (!sbinfo->spool)
1395                         goto out_free;
1396         }
1397         sb->s_maxbytes = MAX_LFS_FILESIZE;
1398         sb->s_blocksize = huge_page_size(ctx->hstate);
1399         sb->s_blocksize_bits = huge_page_shift(ctx->hstate);
1400         sb->s_magic = HUGETLBFS_MAGIC;
1401         sb->s_op = &hugetlbfs_ops;
1402         sb->s_time_gran = 1;
1403
1404         /*
1405          * Due to the special and limited functionality of hugetlbfs, it does
1406          * not work well as a stacking filesystem.
1407          */
1408         sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
1409         sb->s_root = d_make_root(hugetlbfs_get_root(sb, ctx));
1410         if (!sb->s_root)
1411                 goto out_free;
1412         return 0;
1413 out_free:
1414         kfree(sbinfo->spool);
1415         kfree(sbinfo);
1416         return -ENOMEM;
1417 }
1418
1419 static int hugetlbfs_get_tree(struct fs_context *fc)
1420 {
1421         int err = hugetlbfs_validate(fc);
1422         if (err)
1423                 return err;
1424         return get_tree_nodev(fc, hugetlbfs_fill_super);
1425 }
1426
1427 static void hugetlbfs_fs_context_free(struct fs_context *fc)
1428 {
1429         kfree(fc->fs_private);
1430 }
1431
1432 static const struct fs_context_operations hugetlbfs_fs_context_ops = {
1433         .free           = hugetlbfs_fs_context_free,
1434         .parse_param    = hugetlbfs_parse_param,
1435         .get_tree       = hugetlbfs_get_tree,
1436 };
1437
1438 static int hugetlbfs_init_fs_context(struct fs_context *fc)
1439 {
1440         struct hugetlbfs_fs_context *ctx;
1441
1442         ctx = kzalloc(sizeof(struct hugetlbfs_fs_context), GFP_KERNEL);
1443         if (!ctx)
1444                 return -ENOMEM;
1445
1446         ctx->max_hpages = -1; /* No limit on size by default */
1447         ctx->nr_inodes  = -1; /* No limit on number of inodes by default */
1448         ctx->uid        = current_fsuid();
1449         ctx->gid        = current_fsgid();
1450         ctx->mode       = 0755;
1451         ctx->hstate     = &default_hstate;
1452         ctx->min_hpages = -1; /* No default minimum size */
1453         ctx->max_val_type = NO_SIZE;
1454         ctx->min_val_type = NO_SIZE;
1455         fc->fs_private = ctx;
1456         fc->ops = &hugetlbfs_fs_context_ops;
1457         return 0;
1458 }
1459
1460 static struct file_system_type hugetlbfs_fs_type = {
1461         .name                   = "hugetlbfs",
1462         .init_fs_context        = hugetlbfs_init_fs_context,
1463         .parameters             = hugetlb_fs_parameters,
1464         .kill_sb                = kill_litter_super,
1465 };
1466
1467 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1468
1469 static int can_do_hugetlb_shm(void)
1470 {
1471         kgid_t shm_group;
1472         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1473         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1474 }
1475
1476 static int get_hstate_idx(int page_size_log)
1477 {
1478         struct hstate *h = hstate_sizelog(page_size_log);
1479
1480         if (!h)
1481                 return -1;
1482         return hstate_index(h);
1483 }
1484
1485 /*
1486  * Note that size should be aligned to proper hugepage size in caller side,
1487  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1488  */
1489 struct file *hugetlb_file_setup(const char *name, size_t size,
1490                                 vm_flags_t acctflag, int creat_flags,
1491                                 int page_size_log)
1492 {
1493         struct inode *inode;
1494         struct vfsmount *mnt;
1495         int hstate_idx;
1496         struct file *file;
1497
1498         hstate_idx = get_hstate_idx(page_size_log);
1499         if (hstate_idx < 0)
1500                 return ERR_PTR(-ENODEV);
1501
1502         mnt = hugetlbfs_vfsmount[hstate_idx];
1503         if (!mnt)
1504                 return ERR_PTR(-ENOENT);
1505
1506         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1507                 struct ucounts *ucounts = current_ucounts();
1508
1509                 if (user_shm_lock(size, ucounts)) {
1510                         pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is obsolete\n",
1511                                 current->comm, current->pid);
1512                         user_shm_unlock(size, ucounts);
1513                 }
1514                 return ERR_PTR(-EPERM);
1515         }
1516
1517         file = ERR_PTR(-ENOSPC);
1518         inode = hugetlbfs_get_inode(mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0);
1519         if (!inode)
1520                 goto out;
1521         if (creat_flags == HUGETLB_SHMFS_INODE)
1522                 inode->i_flags |= S_PRIVATE;
1523
1524         inode->i_size = size;
1525         clear_nlink(inode);
1526
1527         if (!hugetlb_reserve_pages(inode, 0,
1528                         size >> huge_page_shift(hstate_inode(inode)), NULL,
1529                         acctflag))
1530                 file = ERR_PTR(-ENOMEM);
1531         else
1532                 file = alloc_file_pseudo(inode, mnt, name, O_RDWR,
1533                                         &hugetlbfs_file_operations);
1534         if (!IS_ERR(file))
1535                 return file;
1536
1537         iput(inode);
1538 out:
1539         return file;
1540 }
1541
1542 static struct vfsmount *__init mount_one_hugetlbfs(struct hstate *h)
1543 {
1544         struct fs_context *fc;
1545         struct vfsmount *mnt;
1546
1547         fc = fs_context_for_mount(&hugetlbfs_fs_type, SB_KERNMOUNT);
1548         if (IS_ERR(fc)) {
1549                 mnt = ERR_CAST(fc);
1550         } else {
1551                 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1552                 ctx->hstate = h;
1553                 mnt = fc_mount(fc);
1554                 put_fs_context(fc);
1555         }
1556         if (IS_ERR(mnt))
1557                 pr_err("Cannot mount internal hugetlbfs for page size %luK",
1558                        huge_page_size(h) >> 10);
1559         return mnt;
1560 }
1561
1562 static int __init init_hugetlbfs_fs(void)
1563 {
1564         struct vfsmount *mnt;
1565         struct hstate *h;
1566         int error;
1567         int i;
1568
1569         if (!hugepages_supported()) {
1570                 pr_info("disabling because there are no supported hugepage sizes\n");
1571                 return -ENOTSUPP;
1572         }
1573
1574         error = -ENOMEM;
1575         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1576                                         sizeof(struct hugetlbfs_inode_info),
1577                                         0, SLAB_ACCOUNT, init_once);
1578         if (hugetlbfs_inode_cachep == NULL)
1579                 goto out;
1580
1581         error = register_filesystem(&hugetlbfs_fs_type);
1582         if (error)
1583                 goto out_free;
1584
1585         /* default hstate mount is required */
1586         mnt = mount_one_hugetlbfs(&default_hstate);
1587         if (IS_ERR(mnt)) {
1588                 error = PTR_ERR(mnt);
1589                 goto out_unreg;
1590         }
1591         hugetlbfs_vfsmount[default_hstate_idx] = mnt;
1592
1593         /* other hstates are optional */
1594         i = 0;
1595         for_each_hstate(h) {
1596                 if (i == default_hstate_idx) {
1597                         i++;
1598                         continue;
1599                 }
1600
1601                 mnt = mount_one_hugetlbfs(h);
1602                 if (IS_ERR(mnt))
1603                         hugetlbfs_vfsmount[i] = NULL;
1604                 else
1605                         hugetlbfs_vfsmount[i] = mnt;
1606                 i++;
1607         }
1608
1609         return 0;
1610
1611  out_unreg:
1612         (void)unregister_filesystem(&hugetlbfs_fs_type);
1613  out_free:
1614         kmem_cache_destroy(hugetlbfs_inode_cachep);
1615  out:
1616         return error;
1617 }
1618 fs_initcall(init_hugetlbfs_fs)