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