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/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
  42 static const struct super_operations hugetlbfs_ops;
  43 static const struct address_space_operations hugetlbfs_aops;
  44 const struct file_operations hugetlbfs_file_operations;
  45 static const struct inode_operations hugetlbfs_dir_inode_operations;
  46 static const struct inode_operations hugetlbfs_inode_operations;
  47
  48 struct hugetlbfs_config {
  49         kuid_t   uid;
  50         kgid_t   gid;
  51         umode_t mode;
  52         long    max_hpages;
  53         long    nr_inodes;
  54         struct hstate *hstate;
  55         long    min_hpages;
  56 };
  57
  58 struct hugetlbfs_inode_info {
  59         struct shared_policy policy;
  60         struct inode vfs_inode;
  61 };
  62
  63 static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
  64 {
  65         return container_of(inode, struct hugetlbfs_inode_info, vfs_inode);
  66 }
  67
  68 int sysctl_hugetlb_shm_group;
  69
  70 enum {
  71         Opt_size, Opt_nr_inodes,
  72         Opt_mode, Opt_uid, Opt_gid,
  73         Opt_pagesize, Opt_min_size,
  74         Opt_err,
  75 };
  76
  77 static const match_table_t tokens = {
  78         {Opt_size,      "size=%s"},
  79         {Opt_nr_inodes, "nr_inodes=%s"},
  80         {Opt_mode,      "mode=%o"},
  81         {Opt_uid,       "uid=%u"},
  82         {Opt_gid,       "gid=%u"},
  83         {Opt_pagesize,  "pagesize=%s"},
  84         {Opt_min_size,  "min_size=%s"},
  85         {Opt_err,       NULL},
  86 };
  87
  88 #ifdef CONFIG_NUMA
  89 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
  90                                         struct inode *inode, pgoff_t index)
  91 {
  92         vma->vm_policy = mpol_shared_policy_lookup(&HUGETLBFS_I(inode)->policy,
  93                                                         index);
  94 }
  95
  96 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
  97 {
  98         mpol_cond_put(vma->vm_policy);
  99 }
 100 #else
 101 static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma,
 102                                         struct inode *inode, pgoff_t index)
 103 {
 104 }
 105
 106 static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma)
 107 {
 108 }
 109 #endif
 110
 111 static void huge_pagevec_release(struct pagevec *pvec)
 112 {
 113         int i;
 114
 115         for (i = 0; i < pagevec_count(pvec); ++i)
 116                 put_page(pvec->pages[i]);
 117
 118         pagevec_reinit(pvec);
 119 }
 120
 121 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 122 {
 123         struct inode *inode = file_inode(file);
 124         loff_t len, vma_len;
 125         int ret;
 126         struct hstate *h = hstate_file(file);
 127
 128         /*
 129          * vma address alignment (but not the pgoff alignment) has
 130          * already been checked by prepare_hugepage_range.  If you add
 131          * any error returns here, do so after setting VM_HUGETLB, so
 132          * is_vm_hugetlb_page tests below unmap_region go the right
 133          * way when do_mmap_pgoff unwinds (may be important on powerpc
 134          * and ia64).
 135          */
 136         vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND;
 137         vma->vm_ops = &hugetlb_vm_ops;
 138
 139         /*
 140          * Offset passed to mmap (before page shift) could have been
 141          * negative when represented as a (l)off_t.
 142          */
 143         if (((loff_t)vma->vm_pgoff << PAGE_SHIFT) < 0)
 144                 return -EINVAL;
 145
 146         if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
 147                 return -EINVAL;
 148
 149         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
 150         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 151         /* check for overflow */
 152         if (len < vma_len)
 153                 return -EINVAL;
 154
 155         inode_lock(inode);
 156         file_accessed(file);
 157
 158         ret = -ENOMEM;
 159         if (hugetlb_reserve_pages(inode,
 160                                 vma->vm_pgoff >> huge_page_order(h),
 161                                 len >> huge_page_shift(h), vma,
 162                                 vma->vm_flags))
 163                 goto out;
 164
 165         ret = 0;
 166         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
 167                 i_size_write(inode, len);
 168 out:
 169         inode_unlock(inode);
 170
 171         return ret;
 172 }
 173
 174 /*
 175  * Called under down_write(mmap_sem).
 176  */
 177
 178 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 179 static unsigned long
 180 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 181                 unsigned long len, unsigned long pgoff, unsigned long flags)
 182 {
 183         struct mm_struct *mm = current->mm;
 184         struct vm_area_struct *vma;
 185         struct hstate *h = hstate_file(file);
 186         struct vm_unmapped_area_info info;
 187
 188         if (len & ~huge_page_mask(h))
 189                 return -EINVAL;
 190         if (len > TASK_SIZE)
 191                 return -ENOMEM;
 192
 193         if (flags & MAP_FIXED) {
 194                 if (prepare_hugepage_range(file, addr, len))
 195                         return -EINVAL;
 196                 return addr;
 197         }
 198
 199         if (addr) {
 200                 addr = ALIGN(addr, huge_page_size(h));
 201                 vma = find_vma(mm, addr);
 202                 if (TASK_SIZE - len >= addr &&
 203                     (!vma || addr + len <= vma->vm_start))
 204                         return addr;
 205         }
 206
 207         info.flags = 0;
 208         info.length = len;
 209         info.low_limit = TASK_UNMAPPED_BASE;
 210         info.high_limit = TASK_SIZE;
 211         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 212         info.align_offset = 0;
 213         return vm_unmapped_area(&info);
 214 }
 215 #endif
 216
 217 static size_t
 218 hugetlbfs_read_actor(struct page *page, unsigned long offset,
 219                         struct iov_iter *to, unsigned long size)
 220 {
 221         size_t copied = 0;
 222         int i, chunksize;
 223
 224         /* Find which 4k chunk and offset with in that chunk */
 225         i = offset >> PAGE_SHIFT;
 226         offset = offset & ~PAGE_MASK;
 227
 228         while (size) {
 229                 size_t n;
 230                 chunksize = PAGE_SIZE;
 231                 if (offset)
 232                         chunksize -= offset;
 233                 if (chunksize > size)
 234                         chunksize = size;
 235                 n = copy_page_to_iter(&page[i], offset, chunksize, to);
 236                 copied += n;
 237                 if (n != chunksize)
 238                         return copied;
 239                 offset = 0;
 240                 size -= chunksize;
 241                 i++;
 242         }
 243         return copied;
 244 }
 245
 246 /*
 247  * Support for read() - Find the page attached to f_mapping and copy out the
 248  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
 249  * since it has PAGE_SIZE assumptions.
 250  */
 251 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
 252 {
 253         struct file *file = iocb->ki_filp;
 254         struct hstate *h = hstate_file(file);
 255         struct address_space *mapping = file->f_mapping;
 256         struct inode *inode = mapping->host;
 257         unsigned long index = iocb->ki_pos >> huge_page_shift(h);
 258         unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
 259         unsigned long end_index;
 260         loff_t isize;
 261         ssize_t retval = 0;
 262
 263         while (iov_iter_count(to)) {
 264                 struct page *page;
 265                 size_t nr, copied;
 266
 267                 /* nr is the maximum number of bytes to copy from this page */
 268                 nr = huge_page_size(h);
 269                 isize = i_size_read(inode);
 270                 if (!isize)
 271                         break;
 272                 end_index = (isize - 1) >> huge_page_shift(h);
 273                 if (index > end_index)
 274                         break;
 275                 if (index == end_index) {
 276                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
 277                         if (nr <= offset)
 278                                 break;
 279                 }
 280                 nr = nr - offset;
 281
 282                 /* Find the page */
 283                 page = find_lock_page(mapping, index);
 284                 if (unlikely(page == NULL)) {
 285                         /*
 286                          * We have a HOLE, zero out the user-buffer for the
 287                          * length of the hole or request.
 288                          */
 289                         copied = iov_iter_zero(nr, to);
 290                 } else {
 291                         unlock_page(page);
 292
 293                         /*
 294                          * We have the page, copy it to user space buffer.
 295                          */
 296                         copied = hugetlbfs_read_actor(page, offset, to, nr);
 297                         put_page(page);
 298                 }
 299                 offset += copied;
 300                 retval += copied;
 301                 if (copied != nr && iov_iter_count(to)) {
 302                         if (!retval)
 303                                 retval = -EFAULT;
 304                         break;
 305                 }
 306                 index += offset >> huge_page_shift(h);
 307                 offset &= ~huge_page_mask(h);
 308         }
 309         iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
 310         return retval;
 311 }
 312
 313 static int hugetlbfs_write_begin(struct file *file,
 314                         struct address_space *mapping,
 315                         loff_t pos, unsigned len, unsigned flags,
 316                         struct page **pagep, void **fsdata)
 317 {
 318         return -EINVAL;
 319 }
 320
 321 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
 322                         loff_t pos, unsigned len, unsigned copied,
 323                         struct page *page, void *fsdata)
 324 {
 325         BUG();
 326         return -EINVAL;
 327 }
 328
 329 static void remove_huge_page(struct page *page)
 330 {
 331         ClearPageDirty(page);
 332         ClearPageUptodate(page);
 333         delete_from_page_cache(page);
 334 }
 335
 336 static void
 337 hugetlb_vmdelete_list(struct rb_root *root, pgoff_t start, pgoff_t end)
 338 {
 339         struct vm_area_struct *vma;
 340
 341         /*
 342          * end == 0 indicates that the entire range after
 343          * start should be unmapped.
 344          */
 345         vma_interval_tree_foreach(vma, root, start, end ? end : ULONG_MAX) {
 346                 unsigned long v_offset;
 347                 unsigned long v_end;
 348
 349                 /*
 350                  * Can the expression below overflow on 32-bit arches?
 351                  * No, because the interval tree returns us only those vmas
 352                  * which overlap the truncated area starting at pgoff,
 353                  * and no vma on a 32-bit arch can span beyond the 4GB.
 354                  */
 355                 if (vma->vm_pgoff < start)
 356                         v_offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
 357                 else
 358                         v_offset = 0;
 359
 360                 if (!end)
 361                         v_end = vma->vm_end;
 362                 else {
 363                         v_end = ((end - vma->vm_pgoff) << PAGE_SHIFT)
 364                                                         + vma->vm_start;
 365                         if (v_end > vma->vm_end)
 366                                 v_end = vma->vm_end;
 367                 }
 368
 369                 unmap_hugepage_range(vma, vma->vm_start + v_offset, v_end,
 370                                                                         NULL);
 371         }
 372 }
 373
 374 /*
 375  * remove_inode_hugepages handles two distinct cases: truncation and hole
 376  * punch.  There are subtle differences in operation for each case.
 377  *
 378  * truncation is indicated by end of range being LLONG_MAX
 379  *      In this case, we first scan the range and release found pages.
 380  *      After releasing pages, hugetlb_unreserve_pages cleans up region/reserv
 381  *      maps and global counts.  Page faults can not race with truncation
 382  *      in this routine.  hugetlb_no_page() prevents page faults in the
 383  *      truncated range.  It checks i_size before allocation, and again after
 384  *      with the page table lock for the page held.  The same lock must be
 385  *      acquired to unmap a page.
 386  * hole punch is indicated if end is not LLONG_MAX
 387  *      In the hole punch case we scan the range and release found pages.
 388  *      Only when releasing a page is the associated region/reserv map
 389  *      deleted.  The region/reserv map for ranges without associated
 390  *      pages are not modified.  Page faults can race with hole punch.
 391  *      This is indicated if we find a mapped page.
 392  * Note: If the passed end of range value is beyond the end of file, but
 393  * not LLONG_MAX this routine still performs a hole punch operation.
 394  */
 395 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 396                                    loff_t lend)
 397 {
 398         struct hstate *h = hstate_inode(inode);
 399         struct address_space *mapping = &inode->i_data;
 400         const pgoff_t start = lstart >> huge_page_shift(h);
 401         const pgoff_t end = lend >> huge_page_shift(h);
 402         struct vm_area_struct pseudo_vma;
 403         struct pagevec pvec;
 404         pgoff_t next;
 405         int i, freed = 0;
 406         long lookup_nr = PAGEVEC_SIZE;
 407         bool truncate_op = (lend == LLONG_MAX);
 408
 409         memset(&pseudo_vma, 0, sizeof(struct vm_area_struct));
 410         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
 411         pagevec_init(&pvec, 0);
 412         next = start;
 413         while (next < end) {
 414                 /*
 415                  * Don't grab more pages than the number left in the range.
 416                  */
 417                 if (end - next < lookup_nr)
 418                         lookup_nr = end - next;
 419
 420                 /*
 421                  * When no more pages are found, we are done.
 422                  */
 423                 if (!pagevec_lookup(&pvec, mapping, next, lookup_nr))
 424                         break;
 425
 426                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 427                         struct page *page = pvec.pages[i];
 428                         u32 hash;
 429
 430                         /*
 431                          * The page (index) could be beyond end.  This is
 432                          * only possible in the punch hole case as end is
 433                          * max page offset in the truncate case.
 434                          */
 435                         next = page->index;
 436                         if (next >= end)
 437                                 break;
 438
 439                         hash = hugetlb_fault_mutex_hash(h, current->mm,
 440                                                         &pseudo_vma,
 441                                                         mapping, next, 0);
 442                         mutex_lock(&hugetlb_fault_mutex_table[hash]);
 443
 444                         /*
 445                          * If page is mapped, it was faulted in after being
 446                          * unmapped in caller.  Unmap (again) now after taking
 447                          * the fault mutex.  The mutex will prevent faults
 448                          * until we finish removing the page.
 449                          *
 450                          * This race can only happen in the hole punch case.
 451                          * Getting here in a truncate operation is a bug.
 452                          */
 453                         if (unlikely(page_mapped(page))) {
 454                                 BUG_ON(truncate_op);
 455
 456                                 i_mmap_lock_write(mapping);
 457                                 hugetlb_vmdelete_list(&mapping->i_mmap,
 458                                         next * pages_per_huge_page(h),
 459                                         (next + 1) * pages_per_huge_page(h));
 460                                 i_mmap_unlock_write(mapping);
 461                         }
 462
 463                         lock_page(page);
 464                         /*
 465                          * We must free the huge page and remove from page
 466                          * cache (remove_huge_page) BEFORE removing the
 467                          * region/reserve map (hugetlb_unreserve_pages).  In
 468                          * rare out of memory conditions, removal of the
 469                          * region/reserve map could fail. Correspondingly,
 470                          * the subpool and global reserve usage count can need
 471                          * to be adjusted.
 472                          */
 473                         VM_BUG_ON(PagePrivate(page));
 474                         remove_huge_page(page);
 475                         freed++;
 476                         if (!truncate_op) {
 477                                 if (unlikely(hugetlb_unreserve_pages(inode,
 478                                                         next, next + 1, 1)))
 479                                         hugetlb_fix_reserve_counts(inode);
 480                         }
 481
 482                         unlock_page(page);
 483                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 484                 }
 485                 ++next;
 486                 huge_pagevec_release(&pvec);
 487                 cond_resched();
 488         }
 489
 490         if (truncate_op)
 491                 (void)hugetlb_unreserve_pages(inode, start, LONG_MAX, freed);
 492 }
 493
 494 static void hugetlbfs_evict_inode(struct inode *inode)
 495 {
 496         struct resv_map *resv_map;
 497
 498         remove_inode_hugepages(inode, 0, LLONG_MAX);
 499         resv_map = (struct resv_map *)inode->i_mapping->private_data;
 500         /* root inode doesn't have the resv_map, so we should check it */
 501         if (resv_map)
 502                 resv_map_release(&resv_map->refs);
 503         clear_inode(inode);
 504 }
 505
 506 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 507 {
 508         pgoff_t pgoff;
 509         struct address_space *mapping = inode->i_mapping;
 510         struct hstate *h = hstate_inode(inode);
 511
 512         BUG_ON(offset & ~huge_page_mask(h));
 513         pgoff = offset >> PAGE_SHIFT;
 514
 515         i_size_write(inode, offset);
 516         i_mmap_lock_write(mapping);
 517         if (!RB_EMPTY_ROOT(&mapping->i_mmap))
 518                 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0);
 519         i_mmap_unlock_write(mapping);
 520         remove_inode_hugepages(inode, offset, LLONG_MAX);
 521         return 0;
 522 }
 523
 524 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
 525 {
 526         struct hstate *h = hstate_inode(inode);
 527         loff_t hpage_size = huge_page_size(h);
 528         loff_t hole_start, hole_end;
 529
 530         /*
 531          * For hole punch round up the beginning offset of the hole and
 532          * round down the end.
 533          */
 534         hole_start = round_up(offset, hpage_size);
 535         hole_end = round_down(offset + len, hpage_size);
 536
 537         if (hole_end > hole_start) {
 538                 struct address_space *mapping = inode->i_mapping;
 539
 540                 inode_lock(inode);
 541                 i_mmap_lock_write(mapping);
 542                 if (!RB_EMPTY_ROOT(&mapping->i_mmap))
 543                         hugetlb_vmdelete_list(&mapping->i_mmap,
 544                                                 hole_start >> PAGE_SHIFT,
 545                                                 hole_end  >> PAGE_SHIFT);
 546                 i_mmap_unlock_write(mapping);
 547                 remove_inode_hugepages(inode, hole_start, hole_end);
 548                 inode_unlock(inode);
 549         }
 550
 551         return 0;
 552 }
 553
 554 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
 555                                 loff_t len)
 556 {
 557         struct inode *inode = file_inode(file);
 558         struct address_space *mapping = inode->i_mapping;
 559         struct hstate *h = hstate_inode(inode);
 560         struct vm_area_struct pseudo_vma;
 561         struct mm_struct *mm = current->mm;
 562         loff_t hpage_size = huge_page_size(h);
 563         unsigned long hpage_shift = huge_page_shift(h);
 564         pgoff_t start, index, end;
 565         int error;
 566         u32 hash;
 567
 568         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
 569                 return -EOPNOTSUPP;
 570
 571         if (mode & FALLOC_FL_PUNCH_HOLE)
 572                 return hugetlbfs_punch_hole(inode, offset, len);
 573
 574         /*
 575          * Default preallocate case.
 576          * For this range, start is rounded down and end is rounded up
 577          * as well as being converted to page offsets.
 578          */
 579         start = offset >> hpage_shift;
 580         end = (offset + len + hpage_size - 1) >> hpage_shift;
 581
 582         inode_lock(inode);
 583
 584         /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
 585         error = inode_newsize_ok(inode, offset + len);
 586         if (error)
 587                 goto out;
 588
 589         /*
 590          * Initialize a pseudo vma as this is required by the huge page
 591          * allocation routines.  If NUMA is configured, use page index
 592          * as input to create an allocation policy.
 593          */
 594         memset(&pseudo_vma, 0, sizeof(struct vm_area_struct));
 595         pseudo_vma.vm_flags = (VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
 596         pseudo_vma.vm_file = file;
 597
 598         for (index = start; index < end; index++) {
 599                 /*
 600                  * This is supposed to be the vaddr where the page is being
 601                  * faulted in, but we have no vaddr here.
 602                  */
 603                 struct page *page;
 604                 unsigned long addr;
 605                 int avoid_reserve = 0;
 606
 607                 cond_resched();
 608
 609                 /*
 610                  * fallocate(2) manpage permits EINTR; we may have been
 611                  * interrupted because we are using up too much memory.
 612                  */
 613                 if (signal_pending(current)) {
 614                         error = -EINTR;
 615                         break;
 616                 }
 617
 618                 /* Set numa allocation policy based on index */
 619                 hugetlb_set_vma_policy(&pseudo_vma, inode, index);
 620
 621                 /* addr is the offset within the file (zero based) */
 622                 addr = index * hpage_size;
 623
 624                 /* mutex taken here, fault path and hole punch */
 625                 hash = hugetlb_fault_mutex_hash(h, mm, &pseudo_vma, mapping,
 626                                                 index, addr);
 627                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
 628
 629                 /* See if already present in mapping to avoid alloc/free */
 630                 page = find_get_page(mapping, index);
 631                 if (page) {
 632                         put_page(page);
 633                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 634                         hugetlb_drop_vma_policy(&pseudo_vma);
 635                         continue;
 636                 }
 637
 638                 /* Allocate page and add to page cache */
 639                 page = alloc_huge_page(&pseudo_vma, addr, avoid_reserve);
 640                 hugetlb_drop_vma_policy(&pseudo_vma);
 641                 if (IS_ERR(page)) {
 642                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 643                         error = PTR_ERR(page);
 644                         goto out;
 645                 }
 646                 clear_huge_page(page, addr, pages_per_huge_page(h));
 647                 __SetPageUptodate(page);
 648                 error = huge_add_to_page_cache(page, mapping, index);
 649                 if (unlikely(error)) {
 650                         put_page(page);
 651                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 652                         goto out;
 653                 }
 654
 655                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 656
 657                 /*
 658                  * page_put due to reference from alloc_huge_page()
 659                  * unlock_page because locked by add_to_page_cache()
 660                  */
 661                 put_page(page);
 662                 unlock_page(page);
 663         }
 664
 665         if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
 666                 i_size_write(inode, offset + len);
 667         inode->i_ctime = current_time(inode);
 668 out:
 669         inode_unlock(inode);
 670         return error;
 671 }
 672
 673 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 674 {
 675         struct inode *inode = d_inode(dentry);
 676         struct hstate *h = hstate_inode(inode);
 677         int error;
 678         unsigned int ia_valid = attr->ia_valid;
 679
 680         BUG_ON(!inode);
 681
 682         error = setattr_prepare(dentry, attr);
 683         if (error)
 684                 return error;
 685
 686         if (ia_valid & ATTR_SIZE) {
 687                 error = -EINVAL;
 688                 if (attr->ia_size & ~huge_page_mask(h))
 689                         return -EINVAL;
 690                 error = hugetlb_vmtruncate(inode, attr->ia_size);
 691                 if (error)
 692                         return error;
 693         }
 694
 695         setattr_copy(inode, attr);
 696         mark_inode_dirty(inode);
 697         return 0;
 698 }
 699
 700 static struct inode *hugetlbfs_get_root(struct super_block *sb,
 701                                         struct hugetlbfs_config *config)
 702 {
 703         struct inode *inode;
 704
 705         inode = new_inode(sb);
 706         if (inode) {
 707                 inode->i_ino = get_next_ino();
 708                 inode->i_mode = S_IFDIR | config->mode;
 709                 inode->i_uid = config->uid;
 710                 inode->i_gid = config->gid;
 711                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 712                 inode->i_op = &hugetlbfs_dir_inode_operations;
 713                 inode->i_fop = &simple_dir_operations;
 714                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
 715                 inc_nlink(inode);
 716                 lockdep_annotate_inode_mutex_key(inode);
 717         }
 718         return inode;
 719 }
 720
 721 /*
 722  * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
 723  * be taken from reclaim -- unlike regular filesystems. This needs an
 724  * annotation because huge_pmd_share() does an allocation under hugetlb's
 725  * i_mmap_rwsem.
 726  */
 727 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
 728
 729 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 730                                         struct inode *dir,
 731                                         umode_t mode, dev_t dev)
 732 {
 733         struct inode *inode;
 734         struct resv_map *resv_map;
 735
 736         resv_map = resv_map_alloc();
 737         if (!resv_map)
 738                 return NULL;
 739
 740         inode = new_inode(sb);
 741         if (inode) {
 742                 inode->i_ino = get_next_ino();
 743                 inode_init_owner(inode, dir, mode);
 744                 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
 745                                 &hugetlbfs_i_mmap_rwsem_key);
 746                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 747                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 748                 inode->i_mapping->private_data = resv_map;
 749                 switch (mode & S_IFMT) {
 750                 default:
 751                         init_special_inode(inode, mode, dev);
 752                         break;
 753                 case S_IFREG:
 754                         inode->i_op = &hugetlbfs_inode_operations;
 755                         inode->i_fop = &hugetlbfs_file_operations;
 756                         break;
 757                 case S_IFDIR:
 758                         inode->i_op = &hugetlbfs_dir_inode_operations;
 759                         inode->i_fop = &simple_dir_operations;
 760
 761                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 762                         inc_nlink(inode);
 763                         break;
 764                 case S_IFLNK:
 765                         inode->i_op = &page_symlink_inode_operations;
 766                         inode_nohighmem(inode);
 767                         break;
 768                 }
 769                 lockdep_annotate_inode_mutex_key(inode);
 770         } else
 771                 kref_put(&resv_map->refs, resv_map_release);
 772
 773         return inode;
 774 }
 775
 776 /*
 777  * File creation. Allocate an inode, and we're done..
 778  */
 779 static int hugetlbfs_mknod(struct inode *dir,
 780                         struct dentry *dentry, umode_t mode, dev_t dev)
 781 {
 782         struct inode *inode;
 783         int error = -ENOSPC;
 784
 785         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
 786         if (inode) {
 787                 dir->i_ctime = dir->i_mtime = current_time(dir);
 788                 d_instantiate(dentry, inode);
 789                 dget(dentry);   /* Extra count - pin the dentry in core */
 790                 error = 0;
 791         }
 792         return error;
 793 }
 794
 795 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 796 {
 797         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 798         if (!retval)
 799                 inc_nlink(dir);
 800         return retval;
 801 }
 802
 803 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
 804 {
 805         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 806 }
 807
 808 static int hugetlbfs_symlink(struct inode *dir,
 809                         struct dentry *dentry, const char *symname)
 810 {
 811         struct inode *inode;
 812         int error = -ENOSPC;
 813
 814         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
 815         if (inode) {
 816                 int l = strlen(symname)+1;
 817                 error = page_symlink(inode, symname, l);
 818                 if (!error) {
 819                         d_instantiate(dentry, inode);
 820                         dget(dentry);
 821                 } else
 822                         iput(inode);
 823         }
 824         dir->i_ctime = dir->i_mtime = current_time(dir);
 825
 826         return error;
 827 }
 828
 829 /*
 830  * mark the head page dirty
 831  */
 832 static int hugetlbfs_set_page_dirty(struct page *page)
 833 {
 834         struct page *head = compound_head(page);
 835
 836         SetPageDirty(head);
 837         return 0;
 838 }
 839
 840 static int hugetlbfs_migrate_page(struct address_space *mapping,
 841                                 struct page *newpage, struct page *page,
 842                                 enum migrate_mode mode)
 843 {
 844         int rc;
 845
 846         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
 847         if (rc != MIGRATEPAGE_SUCCESS)
 848                 return rc;
 849         migrate_page_copy(newpage, page);
 850
 851         return MIGRATEPAGE_SUCCESS;
 852 }
 853
 854 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 855 {
 856         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
 857         struct hstate *h = hstate_inode(d_inode(dentry));
 858
 859         buf->f_type = HUGETLBFS_MAGIC;
 860         buf->f_bsize = huge_page_size(h);
 861         if (sbinfo) {
 862                 spin_lock(&sbinfo->stat_lock);
 863                 /* If no limits set, just report 0 for max/free/used
 864                  * blocks, like simple_statfs() */
 865                 if (sbinfo->spool) {
 866                         long free_pages;
 867
 868                         spin_lock(&sbinfo->spool->lock);
 869                         buf->f_blocks = sbinfo->spool->max_hpages;
 870                         free_pages = sbinfo->spool->max_hpages
 871                                 - sbinfo->spool->used_hpages;
 872                         buf->f_bavail = buf->f_bfree = free_pages;
 873                         spin_unlock(&sbinfo->spool->lock);
 874                         buf->f_files = sbinfo->max_inodes;
 875                         buf->f_ffree = sbinfo->free_inodes;
 876                 }
 877                 spin_unlock(&sbinfo->stat_lock);
 878         }
 879         buf->f_namelen = NAME_MAX;
 880         return 0;
 881 }
 882
 883 static void hugetlbfs_put_super(struct super_block *sb)
 884 {
 885         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 886
 887         if (sbi) {
 888                 sb->s_fs_info = NULL;
 889
 890                 if (sbi->spool)
 891                         hugepage_put_subpool(sbi->spool);
 892
 893                 kfree(sbi);
 894         }
 895 }
 896
 897 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 898 {
 899         if (sbinfo->free_inodes >= 0) {
 900                 spin_lock(&sbinfo->stat_lock);
 901                 if (unlikely(!sbinfo->free_inodes)) {
 902                         spin_unlock(&sbinfo->stat_lock);
 903                         return 0;
 904                 }
 905                 sbinfo->free_inodes--;
 906                 spin_unlock(&sbinfo->stat_lock);
 907         }
 908
 909         return 1;
 910 }
 911
 912 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 913 {
 914         if (sbinfo->free_inodes >= 0) {
 915                 spin_lock(&sbinfo->stat_lock);
 916                 sbinfo->free_inodes++;
 917                 spin_unlock(&sbinfo->stat_lock);
 918         }
 919 }
 920
 921
 922 static struct kmem_cache *hugetlbfs_inode_cachep;
 923
 924 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 925 {
 926         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 927         struct hugetlbfs_inode_info *p;
 928
 929         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 930                 return NULL;
 931         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
 932         if (unlikely(!p)) {
 933                 hugetlbfs_inc_free_inodes(sbinfo);
 934                 return NULL;
 935         }
 936
 937         /*
 938          * Any time after allocation, hugetlbfs_destroy_inode can be called
 939          * for the inode.  mpol_free_shared_policy is unconditionally called
 940          * as part of hugetlbfs_destroy_inode.  So, initialize policy here
 941          * in case of a quick call to destroy.
 942          *
 943          * Note that the policy is initialized even if we are creating a
 944          * private inode.  This simplifies hugetlbfs_destroy_inode.
 945          */
 946         mpol_shared_policy_init(&p->policy, NULL);
 947
 948         return &p->vfs_inode;
 949 }
 950
 951 static void hugetlbfs_i_callback(struct rcu_head *head)
 952 {
 953         struct inode *inode = container_of(head, struct inode, i_rcu);
 954         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 955 }
 956
 957 static void hugetlbfs_destroy_inode(struct inode *inode)
 958 {
 959         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 960         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 961         call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
 962 }
 963
 964 static const struct address_space_operations hugetlbfs_aops = {
 965         .write_begin    = hugetlbfs_write_begin,
 966         .write_end      = hugetlbfs_write_end,
 967         .set_page_dirty = hugetlbfs_set_page_dirty,
 968         .migratepage    = hugetlbfs_migrate_page,
 969 };
 970
 971
 972 static void init_once(void *foo)
 973 {
 974         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 975
 976         inode_init_once(&ei->vfs_inode);
 977 }
 978
 979 const struct file_operations hugetlbfs_file_operations = {
 980         .read_iter              = hugetlbfs_read_iter,
 981         .mmap                   = hugetlbfs_file_mmap,
 982         .fsync                  = noop_fsync,
 983         .get_unmapped_area      = hugetlb_get_unmapped_area,
 984         .llseek                 = default_llseek,
 985         .fallocate              = hugetlbfs_fallocate,
 986 };
 987
 988 static const struct inode_operations hugetlbfs_dir_inode_operations = {
 989         .create         = hugetlbfs_create,
 990         .lookup         = simple_lookup,
 991         .link           = simple_link,
 992         .unlink         = simple_unlink,
 993         .symlink        = hugetlbfs_symlink,
 994         .mkdir          = hugetlbfs_mkdir,
 995         .rmdir          = simple_rmdir,
 996         .mknod          = hugetlbfs_mknod,
 997         .rename         = simple_rename,
 998         .setattr        = hugetlbfs_setattr,
 999 };
1000
1001 static const struct inode_operations hugetlbfs_inode_operations = {
1002         .setattr        = hugetlbfs_setattr,
1003 };
1004
1005 static const struct super_operations hugetlbfs_ops = {
1006         .alloc_inode    = hugetlbfs_alloc_inode,
1007         .destroy_inode  = hugetlbfs_destroy_inode,
1008         .evict_inode    = hugetlbfs_evict_inode,
1009         .statfs         = hugetlbfs_statfs,
1010         .put_super      = hugetlbfs_put_super,
1011         .show_options   = generic_show_options,
1012 };
1013
1014 enum { NO_SIZE, SIZE_STD, SIZE_PERCENT };
1015
1016 /*
1017  * Convert size option passed from command line to number of huge pages
1018  * in the pool specified by hstate.  Size option could be in bytes
1019  * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1020  */
1021 static long long
1022 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1023                                                                 int val_type)
1024 {
1025         if (val_type == NO_SIZE)
1026                 return -1;
1027
1028         if (val_type == SIZE_PERCENT) {
1029                 size_opt <<= huge_page_shift(h);
1030                 size_opt *= h->max_huge_pages;
1031                 do_div(size_opt, 100);
1032         }
1033
1034         size_opt >>= huge_page_shift(h);
1035         return size_opt;
1036 }
1037
1038 static int
1039 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
1040 {
1041         char *p, *rest;
1042         substring_t args[MAX_OPT_ARGS];
1043         int option;
1044         unsigned long long max_size_opt = 0, min_size_opt = 0;
1045         int max_val_type = NO_SIZE, min_val_type = NO_SIZE;
1046
1047         if (!options)
1048                 return 0;
1049
1050         while ((p = strsep(&options, ",")) != NULL) {
1051                 int token;
1052                 if (!*p)
1053                         continue;
1054
1055                 token = match_token(p, tokens, args);
1056                 switch (token) {
1057                 case Opt_uid:
1058                         if (match_int(&args[0], &option))
1059                                 goto bad_val;
1060                         pconfig->uid = make_kuid(current_user_ns(), option);
1061                         if (!uid_valid(pconfig->uid))
1062                                 goto bad_val;
1063                         break;
1064
1065                 case Opt_gid:
1066                         if (match_int(&args[0], &option))
1067                                 goto bad_val;
1068                         pconfig->gid = make_kgid(current_user_ns(), option);
1069                         if (!gid_valid(pconfig->gid))
1070                                 goto bad_val;
1071                         break;
1072
1073                 case Opt_mode:
1074                         if (match_octal(&args[0], &option))
1075                                 goto bad_val;
1076                         pconfig->mode = option & 01777U;
1077                         break;
1078
1079                 case Opt_size: {
1080                         /* memparse() will accept a K/M/G without a digit */
1081                         if (!isdigit(*args[0].from))
1082                                 goto bad_val;
1083                         max_size_opt = memparse(args[0].from, &rest);
1084                         max_val_type = SIZE_STD;
1085                         if (*rest == '%')
1086                                 max_val_type = SIZE_PERCENT;
1087                         break;
1088                 }
1089
1090                 case Opt_nr_inodes:
1091                         /* memparse() will accept a K/M/G without a digit */
1092                         if (!isdigit(*args[0].from))
1093                                 goto bad_val;
1094                         pconfig->nr_inodes = memparse(args[0].from, &rest);
1095                         break;
1096
1097                 case Opt_pagesize: {
1098                         unsigned long ps;
1099                         ps = memparse(args[0].from, &rest);
1100                         pconfig->hstate = size_to_hstate(ps);
1101                         if (!pconfig->hstate) {
1102                                 pr_err("Unsupported page size %lu MB\n",
1103                                         ps >> 20);
1104                                 return -EINVAL;
1105                         }
1106                         break;
1107                 }
1108
1109                 case Opt_min_size: {
1110                         /* memparse() will accept a K/M/G without a digit */
1111                         if (!isdigit(*args[0].from))
1112                                 goto bad_val;
1113                         min_size_opt = memparse(args[0].from, &rest);
1114                         min_val_type = SIZE_STD;
1115                         if (*rest == '%')
1116                                 min_val_type = SIZE_PERCENT;
1117                         break;
1118                 }
1119
1120                 default:
1121                         pr_err("Bad mount option: \"%s\"\n", p);
1122                         return -EINVAL;
1123                         break;
1124                 }
1125         }
1126
1127         /*
1128          * Use huge page pool size (in hstate) to convert the size
1129          * options to number of huge pages.  If NO_SIZE, -1 is returned.
1130          */
1131         pconfig->max_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
1132                                                 max_size_opt, max_val_type);
1133         pconfig->min_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
1134                                                 min_size_opt, min_val_type);
1135
1136         /*
1137          * If max_size was specified, then min_size must be smaller
1138          */
1139         if (max_val_type > NO_SIZE &&
1140             pconfig->min_hpages > pconfig->max_hpages) {
1141                 pr_err("minimum size can not be greater than maximum size\n");
1142                 return -EINVAL;
1143         }
1144
1145         return 0;
1146
1147 bad_val:
1148         pr_err("Bad value '%s' for mount option '%s'\n", args[0].from, p);
1149         return -EINVAL;
1150 }
1151
1152 static int
1153 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
1154 {
1155         int ret;
1156         struct hugetlbfs_config config;
1157         struct hugetlbfs_sb_info *sbinfo;
1158
1159         save_mount_options(sb, data);
1160
1161         config.max_hpages = -1; /* No limit on size by default */
1162         config.nr_inodes = -1; /* No limit on number of inodes by default */
1163         config.uid = current_fsuid();
1164         config.gid = current_fsgid();
1165         config.mode = 0755;
1166         config.hstate = &default_hstate;
1167         config.min_hpages = -1; /* No default minimum size */
1168         ret = hugetlbfs_parse_options(data, &config);
1169         if (ret)
1170                 return ret;
1171
1172         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1173         if (!sbinfo)
1174                 return -ENOMEM;
1175         sb->s_fs_info = sbinfo;
1176         sbinfo->hstate = config.hstate;
1177         spin_lock_init(&sbinfo->stat_lock);
1178         sbinfo->max_inodes = config.nr_inodes;
1179         sbinfo->free_inodes = config.nr_inodes;
1180         sbinfo->spool = NULL;
1181         /*
1182          * Allocate and initialize subpool if maximum or minimum size is
1183          * specified.  Any needed reservations (for minimim size) are taken
1184          * taken when the subpool is created.
1185          */
1186         if (config.max_hpages != -1 || config.min_hpages != -1) {
1187                 sbinfo->spool = hugepage_new_subpool(config.hstate,
1188                                                         config.max_hpages,
1189                                                         config.min_hpages);
1190                 if (!sbinfo->spool)
1191                         goto out_free;
1192         }
1193         sb->s_maxbytes = MAX_LFS_FILESIZE;
1194         sb->s_blocksize = huge_page_size(config.hstate);
1195         sb->s_blocksize_bits = huge_page_shift(config.hstate);
1196         sb->s_magic = HUGETLBFS_MAGIC;
1197         sb->s_op = &hugetlbfs_ops;
1198         sb->s_time_gran = 1;
1199         sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
1200         if (!sb->s_root)
1201                 goto out_free;
1202         return 0;
1203 out_free:
1204         kfree(sbinfo->spool);
1205         kfree(sbinfo);
1206         return -ENOMEM;
1207 }
1208
1209 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
1210         int flags, const char *dev_name, void *data)
1211 {
1212         return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
1213 }
1214
1215 static struct file_system_type hugetlbfs_fs_type = {
1216         .name           = "hugetlbfs",
1217         .mount          = hugetlbfs_mount,
1218         .kill_sb        = kill_litter_super,
1219 };
1220
1221 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1222
1223 static int can_do_hugetlb_shm(void)
1224 {
1225         kgid_t shm_group;
1226         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1227         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1228 }
1229
1230 static int get_hstate_idx(int page_size_log)
1231 {
1232         struct hstate *h = hstate_sizelog(page_size_log);
1233
1234         if (!h)
1235                 return -1;
1236         return h - hstates;
1237 }
1238
1239 static const struct dentry_operations anon_ops = {
1240         .d_dname = simple_dname
1241 };
1242
1243 /*
1244  * Note that size should be aligned to proper hugepage size in caller side,
1245  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1246  */
1247 struct file *hugetlb_file_setup(const char *name, size_t size,
1248                                 vm_flags_t acctflag, struct user_struct **user,
1249                                 int creat_flags, int page_size_log)
1250 {
1251         struct file *file = ERR_PTR(-ENOMEM);
1252         struct inode *inode;
1253         struct path path;
1254         struct super_block *sb;
1255         struct qstr quick_string;
1256         int hstate_idx;
1257
1258         hstate_idx = get_hstate_idx(page_size_log);
1259         if (hstate_idx < 0)
1260                 return ERR_PTR(-ENODEV);
1261
1262         *user = NULL;
1263         if (!hugetlbfs_vfsmount[hstate_idx])
1264                 return ERR_PTR(-ENOENT);
1265
1266         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1267                 *user = current_user();
1268                 if (user_shm_lock(size, *user)) {
1269                         task_lock(current);
1270                         pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
1271                                 current->comm, current->pid);
1272                         task_unlock(current);
1273                 } else {
1274                         *user = NULL;
1275                         return ERR_PTR(-EPERM);
1276                 }
1277         }
1278
1279         sb = hugetlbfs_vfsmount[hstate_idx]->mnt_sb;
1280         quick_string.name = name;
1281         quick_string.len = strlen(quick_string.name);
1282         quick_string.hash = 0;
1283         path.dentry = d_alloc_pseudo(sb, &quick_string);
1284         if (!path.dentry)
1285                 goto out_shm_unlock;
1286
1287         d_set_d_op(path.dentry, &anon_ops);
1288         path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]);
1289         file = ERR_PTR(-ENOSPC);
1290         inode = hugetlbfs_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0);
1291         if (!inode)
1292                 goto out_dentry;
1293         if (creat_flags == HUGETLB_SHMFS_INODE)
1294                 inode->i_flags |= S_PRIVATE;
1295
1296         file = ERR_PTR(-ENOMEM);
1297         if (hugetlb_reserve_pages(inode, 0,
1298                         size >> huge_page_shift(hstate_inode(inode)), NULL,
1299                         acctflag))
1300                 goto out_inode;
1301
1302         d_instantiate(path.dentry, inode);
1303         inode->i_size = size;
1304         clear_nlink(inode);
1305
1306         file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
1307                         &hugetlbfs_file_operations);
1308         if (IS_ERR(file))
1309                 goto out_dentry; /* inode is already attached */
1310
1311         return file;
1312
1313 out_inode:
1314         iput(inode);
1315 out_dentry:
1316         path_put(&path);
1317 out_shm_unlock:
1318         if (*user) {
1319                 user_shm_unlock(size, *user);
1320                 *user = NULL;
1321         }
1322         return file;
1323 }
1324
1325 static int __init init_hugetlbfs_fs(void)
1326 {
1327         struct hstate *h;
1328         int error;
1329         int i;
1330
1331         if (!hugepages_supported()) {
1332                 pr_info("disabling because there are no supported hugepage sizes\n");
1333                 return -ENOTSUPP;
1334         }
1335
1336         error = -ENOMEM;
1337         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1338                                         sizeof(struct hugetlbfs_inode_info),
1339                                         0, SLAB_ACCOUNT, init_once);
1340         if (hugetlbfs_inode_cachep == NULL)
1341                 goto out2;
1342
1343         error = register_filesystem(&hugetlbfs_fs_type);
1344         if (error)
1345                 goto out;
1346
1347         i = 0;
1348         for_each_hstate(h) {
1349                 char buf[50];
1350                 unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10);
1351
1352                 snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb);
1353                 hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type,
1354                                                         buf);
1355
1356                 if (IS_ERR(hugetlbfs_vfsmount[i])) {
1357                         pr_err("Cannot mount internal hugetlbfs for "
1358                                 "page size %uK", ps_kb);
1359                         error = PTR_ERR(hugetlbfs_vfsmount[i]);
1360                         hugetlbfs_vfsmount[i] = NULL;
1361                 }
1362                 i++;
1363         }
1364         /* Non default hstates are optional */
1365         if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx]))
1366                 return 0;
1367
1368  out:
1369         kmem_cache_destroy(hugetlbfs_inode_cachep);
1370  out2:
1371         return error;
1372 }
1373 fs_initcall(init_hugetlbfs_fs)