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