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/falloc.h>
  15 #include <linux/fs.h>
  16 #include <linux/mount.h>
  17 #include <linux/file.h>
  18 #include <linux/kernel.h>
  19 #include <linux/writeback.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/highmem.h>
  22 #include <linux/init.h>
  23 #include <linux/string.h>
  24 #include <linux/capability.h>
  25 #include <linux/ctype.h>
  26 #include <linux/backing-dev.h>
  27 #include <linux/hugetlb.h>
  28 #include <linux/pagevec.h>
  29 #include <linux/fs_parser.h>
  30 #include <linux/mman.h>
  31 #include <linux/slab.h>
  32 #include <linux/dnotify.h>
  33 #include <linux/statfs.h>
  34 #include <linux/security.h>
  35 #include <linux/magic.h>
  36 #include <linux/migrate.h>
  37 #include <linux/uio.h>
  38
  39 #include <linux/uaccess.h>
  40 #include <linux/sched/mm.h>
  41
  42 static const struct address_space_operations hugetlbfs_aops;
  43 const struct file_operations hugetlbfs_file_operations;
  44 static const struct inode_operations hugetlbfs_dir_inode_operations;
  45 static const struct inode_operations hugetlbfs_inode_operations;
  46
  47 enum hugetlbfs_size_type { NO_SIZE, SIZE_STD, SIZE_PERCENT };
  48
  49 struct hugetlbfs_fs_context {
  50         struct hstate           *hstate;
  51         unsigned long long      max_size_opt;
  52         unsigned long long      min_size_opt;
  53         long                    max_hpages;
  54         long                    nr_inodes;
  55         long                    min_hpages;
  56         enum hugetlbfs_size_type max_val_type;
  57         enum hugetlbfs_size_type min_val_type;
  58         kuid_t                  uid;
  59         kgid_t                  gid;
  60         umode_t                 mode;
  61 };
  62
  63 int sysctl_hugetlb_shm_group;
  64
  65 enum hugetlb_param {
  66         Opt_gid,
  67         Opt_min_size,
  68         Opt_mode,
  69         Opt_nr_inodes,
  70         Opt_pagesize,
  71         Opt_size,
  72         Opt_uid,
  73 };
  74
  75 static const struct fs_parameter_spec hugetlb_fs_parameters[] = {
  76         fsparam_u32   ("gid",           Opt_gid),
  77         fsparam_string("min_size",      Opt_min_size),
  78         fsparam_u32oct("mode",          Opt_mode),
  79         fsparam_string("nr_inodes",     Opt_nr_inodes),
  80         fsparam_string("pagesize",      Opt_pagesize),
  81         fsparam_string("size",          Opt_size),
  82         fsparam_u32   ("uid",           Opt_uid),
  83         {}
  84 };
  85
  86 /*
  87  * Mask used when checking the page offset value passed in via system
  88  * calls.  This value will be converted to a loff_t which is signed.
  89  * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the
  90  * value.  The extra bit (- 1 in the shift value) is to take the sign
  91  * bit into account.
  92  */
  93 #define PGOFF_LOFFT_MAX \
  94         (((1UL << (PAGE_SHIFT + 1)) - 1) <<  (BITS_PER_LONG - (PAGE_SHIFT + 1)))
  95
  96 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
  97 {
  98         struct inode *inode = file_inode(file);
  99         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 100         loff_t len, vma_len;
 101         int ret;
 102         struct hstate *h = hstate_file(file);
 103
 104         /*
 105          * vma address alignment (but not the pgoff alignment) has
 106          * already been checked by prepare_hugepage_range.  If you add
 107          * any error returns here, do so after setting VM_HUGETLB, so
 108          * is_vm_hugetlb_page tests below unmap_region go the right
 109          * way when do_mmap unwinds (may be important on powerpc
 110          * and ia64).
 111          */
 112         vm_flags_set(vma, VM_HUGETLB | VM_DONTEXPAND);
 113         vma->vm_ops = &hugetlb_vm_ops;
 114
 115         ret = seal_check_write(info->seals, vma);
 116         if (ret)
 117                 return ret;
 118
 119         /*
 120          * page based offset in vm_pgoff could be sufficiently large to
 121          * overflow a loff_t when converted to byte offset.  This can
 122          * only happen on architectures where sizeof(loff_t) ==
 123          * sizeof(unsigned long).  So, only check in those instances.
 124          */
 125         if (sizeof(unsigned long) == sizeof(loff_t)) {
 126                 if (vma->vm_pgoff & PGOFF_LOFFT_MAX)
 127                         return -EINVAL;
 128         }
 129
 130         /* must be huge page aligned */
 131         if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
 132                 return -EINVAL;
 133
 134         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
 135         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 136         /* check for overflow */
 137         if (len < vma_len)
 138                 return -EINVAL;
 139
 140         inode_lock(inode);
 141         file_accessed(file);
 142
 143         ret = -ENOMEM;
 144         if (!hugetlb_reserve_pages(inode,
 145                                 vma->vm_pgoff >> huge_page_order(h),
 146                                 len >> huge_page_shift(h), vma,
 147                                 vma->vm_flags))
 148                 goto out;
 149
 150         ret = 0;
 151         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
 152                 i_size_write(inode, len);
 153 out:
 154         inode_unlock(inode);
 155
 156         return ret;
 157 }
 158
 159 /*
 160  * Called under mmap_write_lock(mm).
 161  */
 162
 163 static unsigned long
 164 hugetlb_get_unmapped_area_bottomup(struct file *file, unsigned long addr,
 165                 unsigned long len, unsigned long pgoff, unsigned long flags)
 166 {
 167         struct hstate *h = hstate_file(file);
 168         struct vm_unmapped_area_info info;
 169
 170         info.flags = 0;
 171         info.length = len;
 172         info.low_limit = current->mm->mmap_base;
 173         info.high_limit = arch_get_mmap_end(addr, len, flags);
 174         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 175         info.align_offset = 0;
 176         return vm_unmapped_area(&info);
 177 }
 178
 179 static unsigned long
 180 hugetlb_get_unmapped_area_topdown(struct file *file, unsigned long addr,
 181                 unsigned long len, unsigned long pgoff, unsigned long flags)
 182 {
 183         struct hstate *h = hstate_file(file);
 184         struct vm_unmapped_area_info info;
 185
 186         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 187         info.length = len;
 188         info.low_limit = PAGE_SIZE;
 189         info.high_limit = arch_get_mmap_base(addr, current->mm->mmap_base);
 190         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 191         info.align_offset = 0;
 192         addr = vm_unmapped_area(&info);
 193
 194         /*
 195          * A failed mmap() very likely causes application failure,
 196          * so fall back to the bottom-up function here. This scenario
 197          * can happen with large stack limits and large mmap()
 198          * allocations.
 199          */
 200         if (unlikely(offset_in_page(addr))) {
 201                 VM_BUG_ON(addr != -ENOMEM);
 202                 info.flags = 0;
 203                 info.low_limit = current->mm->mmap_base;
 204                 info.high_limit = arch_get_mmap_end(addr, len, flags);
 205                 addr = vm_unmapped_area(&info);
 206         }
 207
 208         return addr;
 209 }
 210
 211 unsigned long
 212 generic_hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 213                                   unsigned long len, unsigned long pgoff,
 214                                   unsigned long flags)
 215 {
 216         struct mm_struct *mm = current->mm;
 217         struct vm_area_struct *vma;
 218         struct hstate *h = hstate_file(file);
 219         const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags);
 220
 221         if (len & ~huge_page_mask(h))
 222                 return -EINVAL;
 223         if (len > TASK_SIZE)
 224                 return -ENOMEM;
 225
 226         if (flags & MAP_FIXED) {
 227                 if (prepare_hugepage_range(file, addr, len))
 228                         return -EINVAL;
 229                 return addr;
 230         }
 231
 232         if (addr) {
 233                 addr = ALIGN(addr, huge_page_size(h));
 234                 vma = find_vma(mm, addr);
 235                 if (mmap_end - len >= addr &&
 236                     (!vma || addr + len <= vm_start_gap(vma)))
 237                         return addr;
 238         }
 239
 240         /*
 241          * Use mm->get_unmapped_area value as a hint to use topdown routine.
 242          * If architectures have special needs, they should define their own
 243          * version of hugetlb_get_unmapped_area.
 244          */
 245         if (mm->get_unmapped_area == arch_get_unmapped_area_topdown)
 246                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 247                                 pgoff, flags);
 248         return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 249                         pgoff, flags);
 250 }
 251
 252 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 253 static unsigned long
 254 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 255                           unsigned long len, unsigned long pgoff,
 256                           unsigned long flags)
 257 {
 258         return generic_hugetlb_get_unmapped_area(file, addr, len, pgoff, flags);
 259 }
 260 #endif
 261
 262 /*
 263  * Someone wants to read @bytes from a HWPOISON hugetlb @page from @offset.
 264  * Returns the maximum number of bytes one can read without touching the 1st raw
 265  * HWPOISON subpage.
 266  *
 267  * The implementation borrows the iteration logic from copy_page_to_iter*.
 268  */
 269 static size_t adjust_range_hwpoison(struct page *page, size_t offset, size_t bytes)
 270 {
 271         size_t n = 0;
 272         size_t res = 0;
 273
 274         /* First subpage to start the loop. */
 275         page = nth_page(page, offset / PAGE_SIZE);
 276         offset %= PAGE_SIZE;
 277         while (1) {
 278                 if (is_raw_hwpoison_page_in_hugepage(page))
 279                         break;
 280
 281                 /* Safe to read n bytes without touching HWPOISON subpage. */
 282                 n = min(bytes, (size_t)PAGE_SIZE - offset);
 283                 res += n;
 284                 bytes -= n;
 285                 if (!bytes || !n)
 286                         break;
 287                 offset += n;
 288                 if (offset == PAGE_SIZE) {
 289                         page = nth_page(page, 1);
 290                         offset = 0;
 291                 }
 292         }
 293
 294         return res;
 295 }
 296
 297 /*
 298  * Support for read() - Find the page attached to f_mapping and copy out the
 299  * data. This provides functionality similar to filemap_read().
 300  */
 301 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
 302 {
 303         struct file *file = iocb->ki_filp;
 304         struct hstate *h = hstate_file(file);
 305         struct address_space *mapping = file->f_mapping;
 306         struct inode *inode = mapping->host;
 307         unsigned long index = iocb->ki_pos >> huge_page_shift(h);
 308         unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
 309         unsigned long end_index;
 310         loff_t isize;
 311         ssize_t retval = 0;
 312
 313         while (iov_iter_count(to)) {
 314                 struct folio *folio;
 315                 size_t nr, copied, want;
 316
 317                 /* nr is the maximum number of bytes to copy from this page */
 318                 nr = huge_page_size(h);
 319                 isize = i_size_read(inode);
 320                 if (!isize)
 321                         break;
 322                 end_index = (isize - 1) >> huge_page_shift(h);
 323                 if (index > end_index)
 324                         break;
 325                 if (index == end_index) {
 326                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
 327                         if (nr <= offset)
 328                                 break;
 329                 }
 330                 nr = nr - offset;
 331
 332                 /* Find the folio */
 333                 folio = filemap_lock_hugetlb_folio(h, mapping, index);
 334                 if (IS_ERR(folio)) {
 335                         /*
 336                          * We have a HOLE, zero out the user-buffer for the
 337                          * length of the hole or request.
 338                          */
 339                         copied = iov_iter_zero(nr, to);
 340                 } else {
 341                         folio_unlock(folio);
 342
 343                         if (!folio_test_has_hwpoisoned(folio))
 344                                 want = nr;
 345                         else {
 346                                 /*
 347                                  * Adjust how many bytes safe to read without
 348                                  * touching the 1st raw HWPOISON subpage after
 349                                  * offset.
 350                                  */
 351                                 want = adjust_range_hwpoison(&folio->page, offset, nr);
 352                                 if (want == 0) {
 353                                         folio_put(folio);
 354                                         retval = -EIO;
 355                                         break;
 356                                 }
 357                         }
 358
 359                         /*
 360                          * We have the folio, copy it to user space buffer.
 361                          */
 362                         copied = copy_folio_to_iter(folio, offset, want, to);
 363                         folio_put(folio);
 364                 }
 365                 offset += copied;
 366                 retval += copied;
 367                 if (copied != nr && iov_iter_count(to)) {
 368                         if (!retval)
 369                                 retval = -EFAULT;
 370                         break;
 371                 }
 372                 index += offset >> huge_page_shift(h);
 373                 offset &= ~huge_page_mask(h);
 374         }
 375         iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
 376         return retval;
 377 }
 378
 379 static int hugetlbfs_write_begin(struct file *file,
 380                         struct address_space *mapping,
 381                         loff_t pos, unsigned len,
 382                         struct page **pagep, void **fsdata)
 383 {
 384         return -EINVAL;
 385 }
 386
 387 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
 388                         loff_t pos, unsigned len, unsigned copied,
 389                         struct page *page, void *fsdata)
 390 {
 391         BUG();
 392         return -EINVAL;
 393 }
 394
 395 static void hugetlb_delete_from_page_cache(struct folio *folio)
 396 {
 397         folio_clear_dirty(folio);
 398         folio_clear_uptodate(folio);
 399         filemap_remove_folio(folio);
 400 }
 401
 402 /*
 403  * Called with i_mmap_rwsem held for inode based vma maps.  This makes
 404  * sure vma (and vm_mm) will not go away.  We also hold the hugetlb fault
 405  * mutex for the page in the mapping.  So, we can not race with page being
 406  * faulted into the vma.
 407  */
 408 static bool hugetlb_vma_maps_page(struct vm_area_struct *vma,
 409                                 unsigned long addr, struct page *page)
 410 {
 411         pte_t *ptep, pte;
 412
 413         ptep = hugetlb_walk(vma, addr, huge_page_size(hstate_vma(vma)));
 414         if (!ptep)
 415                 return false;
 416
 417         pte = huge_ptep_get(ptep);
 418         if (huge_pte_none(pte) || !pte_present(pte))
 419                 return false;
 420
 421         if (pte_page(pte) == page)
 422                 return true;
 423
 424         return false;
 425 }
 426
 427 /*
 428  * Can vma_offset_start/vma_offset_end overflow on 32-bit arches?
 429  * No, because the interval tree returns us only those vmas
 430  * which overlap the truncated area starting at pgoff,
 431  * and no vma on a 32-bit arch can span beyond the 4GB.
 432  */
 433 static unsigned long vma_offset_start(struct vm_area_struct *vma, pgoff_t start)
 434 {
 435         unsigned long offset = 0;
 436
 437         if (vma->vm_pgoff < start)
 438                 offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
 439
 440         return vma->vm_start + offset;
 441 }
 442
 443 static unsigned long vma_offset_end(struct vm_area_struct *vma, pgoff_t end)
 444 {
 445         unsigned long t_end;
 446
 447         if (!end)
 448                 return vma->vm_end;
 449
 450         t_end = ((end - vma->vm_pgoff) << PAGE_SHIFT) + vma->vm_start;
 451         if (t_end > vma->vm_end)
 452                 t_end = vma->vm_end;
 453         return t_end;
 454 }
 455
 456 /*
 457  * Called with hugetlb fault mutex held.  Therefore, no more mappings to
 458  * this folio can be created while executing the routine.
 459  */
 460 static void hugetlb_unmap_file_folio(struct hstate *h,
 461                                         struct address_space *mapping,
 462                                         struct folio *folio, pgoff_t index)
 463 {
 464         struct rb_root_cached *root = &mapping->i_mmap;
 465         struct hugetlb_vma_lock *vma_lock;
 466         struct page *page = &folio->page;
 467         struct vm_area_struct *vma;
 468         unsigned long v_start;
 469         unsigned long v_end;
 470         pgoff_t start, end;
 471
 472         start = index * pages_per_huge_page(h);
 473         end = (index + 1) * pages_per_huge_page(h);
 474
 475         i_mmap_lock_write(mapping);
 476 retry:
 477         vma_lock = NULL;
 478         vma_interval_tree_foreach(vma, root, start, end - 1) {
 479                 v_start = vma_offset_start(vma, start);
 480                 v_end = vma_offset_end(vma, end);
 481
 482                 if (!hugetlb_vma_maps_page(vma, v_start, page))
 483                         continue;
 484
 485                 if (!hugetlb_vma_trylock_write(vma)) {
 486                         vma_lock = vma->vm_private_data;
 487                         /*
 488                          * If we can not get vma lock, we need to drop
 489                          * immap_sema and take locks in order.  First,
 490                          * take a ref on the vma_lock structure so that
 491                          * we can be guaranteed it will not go away when
 492                          * dropping immap_sema.
 493                          */
 494                         kref_get(&vma_lock->refs);
 495                         break;
 496                 }
 497
 498                 unmap_hugepage_range(vma, v_start, v_end, NULL,
 499                                      ZAP_FLAG_DROP_MARKER);
 500                 hugetlb_vma_unlock_write(vma);
 501         }
 502
 503         i_mmap_unlock_write(mapping);
 504
 505         if (vma_lock) {
 506                 /*
 507                  * Wait on vma_lock.  We know it is still valid as we have
 508                  * a reference.  We must 'open code' vma locking as we do
 509                  * not know if vma_lock is still attached to vma.
 510                  */
 511                 down_write(&vma_lock->rw_sema);
 512                 i_mmap_lock_write(mapping);
 513
 514                 vma = vma_lock->vma;
 515                 if (!vma) {
 516                         /*
 517                          * If lock is no longer attached to vma, then just
 518                          * unlock, drop our reference and retry looking for
 519                          * other vmas.
 520                          */
 521                         up_write(&vma_lock->rw_sema);
 522                         kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
 523                         goto retry;
 524                 }
 525
 526                 /*
 527                  * vma_lock is still attached to vma.  Check to see if vma
 528                  * still maps page and if so, unmap.
 529                  */
 530                 v_start = vma_offset_start(vma, start);
 531                 v_end = vma_offset_end(vma, end);
 532                 if (hugetlb_vma_maps_page(vma, v_start, page))
 533                         unmap_hugepage_range(vma, v_start, v_end, NULL,
 534                                              ZAP_FLAG_DROP_MARKER);
 535
 536                 kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
 537                 hugetlb_vma_unlock_write(vma);
 538
 539                 goto retry;
 540         }
 541 }
 542
 543 static void
 544 hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end,
 545                       zap_flags_t zap_flags)
 546 {
 547         struct vm_area_struct *vma;
 548
 549         /*
 550          * end == 0 indicates that the entire range after start should be
 551          * unmapped.  Note, end is exclusive, whereas the interval tree takes
 552          * an inclusive "last".
 553          */
 554         vma_interval_tree_foreach(vma, root, start, end ? end - 1 : ULONG_MAX) {
 555                 unsigned long v_start;
 556                 unsigned long v_end;
 557
 558                 if (!hugetlb_vma_trylock_write(vma))
 559                         continue;
 560
 561                 v_start = vma_offset_start(vma, start);
 562                 v_end = vma_offset_end(vma, end);
 563
 564                 unmap_hugepage_range(vma, v_start, v_end, NULL, zap_flags);
 565
 566                 /*
 567                  * Note that vma lock only exists for shared/non-private
 568                  * vmas.  Therefore, lock is not held when calling
 569                  * unmap_hugepage_range for private vmas.
 570                  */
 571                 hugetlb_vma_unlock_write(vma);
 572         }
 573 }
 574
 575 /*
 576  * Called with hugetlb fault mutex held.
 577  * Returns true if page was actually removed, false otherwise.
 578  */
 579 static bool remove_inode_single_folio(struct hstate *h, struct inode *inode,
 580                                         struct address_space *mapping,
 581                                         struct folio *folio, pgoff_t index,
 582                                         bool truncate_op)
 583 {
 584         bool ret = false;
 585
 586         /*
 587          * If folio is mapped, it was faulted in after being
 588          * unmapped in caller.  Unmap (again) while holding
 589          * the fault mutex.  The mutex will prevent faults
 590          * until we finish removing the folio.
 591          */
 592         if (unlikely(folio_mapped(folio)))
 593                 hugetlb_unmap_file_folio(h, mapping, folio, index);
 594
 595         folio_lock(folio);
 596         /*
 597          * We must remove the folio from page cache before removing
 598          * the region/ reserve map (hugetlb_unreserve_pages).  In
 599          * rare out of memory conditions, removal of the region/reserve
 600          * map could fail.  Correspondingly, the subpool and global
 601          * reserve usage count can need to be adjusted.
 602          */
 603         VM_BUG_ON_FOLIO(folio_test_hugetlb_restore_reserve(folio), folio);
 604         hugetlb_delete_from_page_cache(folio);
 605         ret = true;
 606         if (!truncate_op) {
 607                 if (unlikely(hugetlb_unreserve_pages(inode, index,
 608                                                         index + 1, 1)))
 609                         hugetlb_fix_reserve_counts(inode);
 610         }
 611
 612         folio_unlock(folio);
 613         return ret;
 614 }
 615
 616 /*
 617  * remove_inode_hugepages handles two distinct cases: truncation and hole
 618  * punch.  There are subtle differences in operation for each case.
 619  *
 620  * truncation is indicated by end of range being LLONG_MAX
 621  *      In this case, we first scan the range and release found pages.
 622  *      After releasing pages, hugetlb_unreserve_pages cleans up region/reserve
 623  *      maps and global counts.  Page faults can race with truncation.
 624  *      During faults, hugetlb_no_page() checks i_size before page allocation,
 625  *      and again after obtaining page table lock.  It will 'back out'
 626  *      allocations in the truncated range.
 627  * hole punch is indicated if end is not LLONG_MAX
 628  *      In the hole punch case we scan the range and release found pages.
 629  *      Only when releasing a page is the associated region/reserve map
 630  *      deleted.  The region/reserve map for ranges without associated
 631  *      pages are not modified.  Page faults can race with hole punch.
 632  *      This is indicated if we find a mapped page.
 633  * Note: If the passed end of range value is beyond the end of file, but
 634  * not LLONG_MAX this routine still performs a hole punch operation.
 635  */
 636 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 637                                    loff_t lend)
 638 {
 639         struct hstate *h = hstate_inode(inode);
 640         struct address_space *mapping = &inode->i_data;
 641         const pgoff_t end = lend >> PAGE_SHIFT;
 642         struct folio_batch fbatch;
 643         pgoff_t next, index;
 644         int i, freed = 0;
 645         bool truncate_op = (lend == LLONG_MAX);
 646
 647         folio_batch_init(&fbatch);
 648         next = lstart >> PAGE_SHIFT;
 649         while (filemap_get_folios(mapping, &next, end - 1, &fbatch)) {
 650                 for (i = 0; i < folio_batch_count(&fbatch); ++i) {
 651                         struct folio *folio = fbatch.folios[i];
 652                         u32 hash = 0;
 653
 654                         index = folio->index >> huge_page_order(h);
 655                         hash = hugetlb_fault_mutex_hash(mapping, index);
 656                         mutex_lock(&hugetlb_fault_mutex_table[hash]);
 657
 658                         /*
 659                          * Remove folio that was part of folio_batch.
 660                          */
 661                         if (remove_inode_single_folio(h, inode, mapping, folio,
 662                                                         index, truncate_op))
 663                                 freed++;
 664
 665                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 666                 }
 667                 folio_batch_release(&fbatch);
 668                 cond_resched();
 669         }
 670
 671         if (truncate_op)
 672                 (void)hugetlb_unreserve_pages(inode,
 673                                 lstart >> huge_page_shift(h),
 674                                 LONG_MAX, freed);
 675 }
 676
 677 static void hugetlbfs_evict_inode(struct inode *inode)
 678 {
 679         struct resv_map *resv_map;
 680
 681         remove_inode_hugepages(inode, 0, LLONG_MAX);
 682
 683         /*
 684          * Get the resv_map from the address space embedded in the inode.
 685          * This is the address space which points to any resv_map allocated
 686          * at inode creation time.  If this is a device special inode,
 687          * i_mapping may not point to the original address space.
 688          */
 689         resv_map = (struct resv_map *)(&inode->i_data)->private_data;
 690         /* Only regular and link inodes have associated reserve maps */
 691         if (resv_map)
 692                 resv_map_release(&resv_map->refs);
 693         clear_inode(inode);
 694 }
 695
 696 static void hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 697 {
 698         pgoff_t pgoff;
 699         struct address_space *mapping = inode->i_mapping;
 700         struct hstate *h = hstate_inode(inode);
 701
 702         BUG_ON(offset & ~huge_page_mask(h));
 703         pgoff = offset >> PAGE_SHIFT;
 704
 705         i_size_write(inode, offset);
 706         i_mmap_lock_write(mapping);
 707         if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
 708                 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0,
 709                                       ZAP_FLAG_DROP_MARKER);
 710         i_mmap_unlock_write(mapping);
 711         remove_inode_hugepages(inode, offset, LLONG_MAX);
 712 }
 713
 714 static void hugetlbfs_zero_partial_page(struct hstate *h,
 715                                         struct address_space *mapping,
 716                                         loff_t start,
 717                                         loff_t end)
 718 {
 719         pgoff_t idx = start >> huge_page_shift(h);
 720         struct folio *folio;
 721
 722         folio = filemap_lock_hugetlb_folio(h, mapping, idx);
 723         if (IS_ERR(folio))
 724                 return;
 725
 726         start = start & ~huge_page_mask(h);
 727         end = end & ~huge_page_mask(h);
 728         if (!end)
 729                 end = huge_page_size(h);
 730
 731         folio_zero_segment(folio, (size_t)start, (size_t)end);
 732
 733         folio_unlock(folio);
 734         folio_put(folio);
 735 }
 736
 737 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
 738 {
 739         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 740         struct address_space *mapping = inode->i_mapping;
 741         struct hstate *h = hstate_inode(inode);
 742         loff_t hpage_size = huge_page_size(h);
 743         loff_t hole_start, hole_end;
 744
 745         /*
 746          * hole_start and hole_end indicate the full pages within the hole.
 747          */
 748         hole_start = round_up(offset, hpage_size);
 749         hole_end = round_down(offset + len, hpage_size);
 750
 751         inode_lock(inode);
 752
 753         /* protected by i_rwsem */
 754         if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) {
 755                 inode_unlock(inode);
 756                 return -EPERM;
 757         }
 758
 759         i_mmap_lock_write(mapping);
 760
 761         /* If range starts before first full page, zero partial page. */
 762         if (offset < hole_start)
 763                 hugetlbfs_zero_partial_page(h, mapping,
 764                                 offset, min(offset + len, hole_start));
 765
 766         /* Unmap users of full pages in the hole. */
 767         if (hole_end > hole_start) {
 768                 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
 769                         hugetlb_vmdelete_list(&mapping->i_mmap,
 770                                               hole_start >> PAGE_SHIFT,
 771                                               hole_end >> PAGE_SHIFT, 0);
 772         }
 773
 774         /* If range extends beyond last full page, zero partial page. */
 775         if ((offset + len) > hole_end && (offset + len) > hole_start)
 776                 hugetlbfs_zero_partial_page(h, mapping,
 777                                 hole_end, offset + len);
 778
 779         i_mmap_unlock_write(mapping);
 780
 781         /* Remove full pages from the file. */
 782         if (hole_end > hole_start)
 783                 remove_inode_hugepages(inode, hole_start, hole_end);
 784
 785         inode_unlock(inode);
 786
 787         return 0;
 788 }
 789
 790 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
 791                                 loff_t len)
 792 {
 793         struct inode *inode = file_inode(file);
 794         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 795         struct address_space *mapping = inode->i_mapping;
 796         struct hstate *h = hstate_inode(inode);
 797         struct vm_area_struct pseudo_vma;
 798         struct mm_struct *mm = current->mm;
 799         loff_t hpage_size = huge_page_size(h);
 800         unsigned long hpage_shift = huge_page_shift(h);
 801         pgoff_t start, index, end;
 802         int error;
 803         u32 hash;
 804
 805         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
 806                 return -EOPNOTSUPP;
 807
 808         if (mode & FALLOC_FL_PUNCH_HOLE)
 809                 return hugetlbfs_punch_hole(inode, offset, len);
 810
 811         /*
 812          * Default preallocate case.
 813          * For this range, start is rounded down and end is rounded up
 814          * as well as being converted to page offsets.
 815          */
 816         start = offset >> hpage_shift;
 817         end = (offset + len + hpage_size - 1) >> hpage_shift;
 818
 819         inode_lock(inode);
 820
 821         /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
 822         error = inode_newsize_ok(inode, offset + len);
 823         if (error)
 824                 goto out;
 825
 826         if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) {
 827                 error = -EPERM;
 828                 goto out;
 829         }
 830
 831         /*
 832          * Initialize a pseudo vma as this is required by the huge page
 833          * allocation routines.
 834          */
 835         vma_init(&pseudo_vma, mm);
 836         vm_flags_init(&pseudo_vma, VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
 837         pseudo_vma.vm_file = file;
 838
 839         for (index = start; index < end; index++) {
 840                 /*
 841                  * This is supposed to be the vaddr where the page is being
 842                  * faulted in, but we have no vaddr here.
 843                  */
 844                 struct folio *folio;
 845                 unsigned long addr;
 846
 847                 cond_resched();
 848
 849                 /*
 850                  * fallocate(2) manpage permits EINTR; we may have been
 851                  * interrupted because we are using up too much memory.
 852                  */
 853                 if (signal_pending(current)) {
 854                         error = -EINTR;
 855                         break;
 856                 }
 857
 858                 /* addr is the offset within the file (zero based) */
 859                 addr = index * hpage_size;
 860
 861                 /* mutex taken here, fault path and hole punch */
 862                 hash = hugetlb_fault_mutex_hash(mapping, index);
 863                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
 864
 865                 /* See if already present in mapping to avoid alloc/free */
 866                 folio = filemap_get_folio(mapping, index << huge_page_order(h));
 867                 if (!IS_ERR(folio)) {
 868                         folio_put(folio);
 869                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 870                         continue;
 871                 }
 872
 873                 /*
 874                  * Allocate folio without setting the avoid_reserve argument.
 875                  * There certainly are no reserves associated with the
 876                  * pseudo_vma.  However, there could be shared mappings with
 877                  * reserves for the file at the inode level.  If we fallocate
 878                  * folios in these areas, we need to consume the reserves
 879                  * to keep reservation accounting consistent.
 880                  */
 881                 folio = alloc_hugetlb_folio(&pseudo_vma, addr, 0);
 882                 if (IS_ERR(folio)) {
 883                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 884                         error = PTR_ERR(folio);
 885                         goto out;
 886                 }
 887                 clear_huge_page(&folio->page, addr, pages_per_huge_page(h));
 888                 __folio_mark_uptodate(folio);
 889                 error = hugetlb_add_to_page_cache(folio, mapping, index);
 890                 if (unlikely(error)) {
 891                         restore_reserve_on_error(h, &pseudo_vma, addr, folio);
 892                         folio_put(folio);
 893                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 894                         goto out;
 895                 }
 896
 897                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 898
 899                 folio_set_hugetlb_migratable(folio);
 900                 /*
 901                  * folio_unlock because locked by hugetlb_add_to_page_cache()
 902                  * folio_put() due to reference from alloc_hugetlb_folio()
 903                  */
 904                 folio_unlock(folio);
 905                 folio_put(folio);
 906         }
 907
 908         if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
 909                 i_size_write(inode, offset + len);
 910         inode_set_ctime_current(inode);
 911 out:
 912         inode_unlock(inode);
 913         return error;
 914 }
 915
 916 static int hugetlbfs_setattr(struct mnt_idmap *idmap,
 917                              struct dentry *dentry, struct iattr *attr)
 918 {
 919         struct inode *inode = d_inode(dentry);
 920         struct hstate *h = hstate_inode(inode);
 921         int error;
 922         unsigned int ia_valid = attr->ia_valid;
 923         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 924
 925         error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 926         if (error)
 927                 return error;
 928
 929         if (ia_valid & ATTR_SIZE) {
 930                 loff_t oldsize = inode->i_size;
 931                 loff_t newsize = attr->ia_size;
 932
 933                 if (newsize & ~huge_page_mask(h))
 934                         return -EINVAL;
 935                 /* protected by i_rwsem */
 936                 if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
 937                     (newsize > oldsize && (info->seals & F_SEAL_GROW)))
 938                         return -EPERM;
 939                 hugetlb_vmtruncate(inode, newsize);
 940         }
 941
 942         setattr_copy(&nop_mnt_idmap, inode, attr);
 943         mark_inode_dirty(inode);
 944         return 0;
 945 }
 946
 947 static struct inode *hugetlbfs_get_root(struct super_block *sb,
 948                                         struct hugetlbfs_fs_context *ctx)
 949 {
 950         struct inode *inode;
 951
 952         inode = new_inode(sb);
 953         if (inode) {
 954                 inode->i_ino = get_next_ino();
 955                 inode->i_mode = S_IFDIR | ctx->mode;
 956                 inode->i_uid = ctx->uid;
 957                 inode->i_gid = ctx->gid;
 958                 simple_inode_init_ts(inode);
 959                 inode->i_op = &hugetlbfs_dir_inode_operations;
 960                 inode->i_fop = &simple_dir_operations;
 961                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
 962                 inc_nlink(inode);
 963                 lockdep_annotate_inode_mutex_key(inode);
 964         }
 965         return inode;
 966 }
 967
 968 /*
 969  * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
 970  * be taken from reclaim -- unlike regular filesystems. This needs an
 971  * annotation because huge_pmd_share() does an allocation under hugetlb's
 972  * i_mmap_rwsem.
 973  */
 974 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
 975
 976 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 977                                         struct inode *dir,
 978                                         umode_t mode, dev_t dev)
 979 {
 980         struct inode *inode;
 981         struct resv_map *resv_map = NULL;
 982
 983         /*
 984          * Reserve maps are only needed for inodes that can have associated
 985          * page allocations.
 986          */
 987         if (S_ISREG(mode) || S_ISLNK(mode)) {
 988                 resv_map = resv_map_alloc();
 989                 if (!resv_map)
 990                         return NULL;
 991         }
 992
 993         inode = new_inode(sb);
 994         if (inode) {
 995                 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 996
 997                 inode->i_ino = get_next_ino();
 998                 inode_init_owner(&nop_mnt_idmap, inode, dir, mode);
 999                 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
1000                                 &hugetlbfs_i_mmap_rwsem_key);
1001                 inode->i_mapping->a_ops = &hugetlbfs_aops;
1002                 simple_inode_init_ts(inode);
1003                 inode->i_mapping->private_data = resv_map;
1004                 info->seals = F_SEAL_SEAL;
1005                 switch (mode & S_IFMT) {
1006                 default:
1007                         init_special_inode(inode, mode, dev);
1008                         break;
1009                 case S_IFREG:
1010                         inode->i_op = &hugetlbfs_inode_operations;
1011                         inode->i_fop = &hugetlbfs_file_operations;
1012                         break;
1013                 case S_IFDIR:
1014                         inode->i_op = &hugetlbfs_dir_inode_operations;
1015                         inode->i_fop = &simple_dir_operations;
1016
1017                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
1018                         inc_nlink(inode);
1019                         break;
1020                 case S_IFLNK:
1021                         inode->i_op = &page_symlink_inode_operations;
1022                         inode_nohighmem(inode);
1023                         break;
1024                 }
1025                 lockdep_annotate_inode_mutex_key(inode);
1026         } else {
1027                 if (resv_map)
1028                         kref_put(&resv_map->refs, resv_map_release);
1029         }
1030
1031         return inode;
1032 }
1033
1034 /*
1035  * File creation. Allocate an inode, and we're done..
1036  */
1037 static int hugetlbfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
1038                            struct dentry *dentry, umode_t mode, dev_t dev)
1039 {
1040         struct inode *inode;
1041
1042         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
1043         if (!inode)
1044                 return -ENOSPC;
1045         inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
1046         d_instantiate(dentry, inode);
1047         dget(dentry);/* Extra count - pin the dentry in core */
1048         return 0;
1049 }
1050
1051 static int hugetlbfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
1052                            struct dentry *dentry, umode_t mode)
1053 {
1054         int retval = hugetlbfs_mknod(&nop_mnt_idmap, dir, dentry,
1055                                      mode | S_IFDIR, 0);
1056         if (!retval)
1057                 inc_nlink(dir);
1058         return retval;
1059 }
1060
1061 static int hugetlbfs_create(struct mnt_idmap *idmap,
1062                             struct inode *dir, struct dentry *dentry,
1063                             umode_t mode, bool excl)
1064 {
1065         return hugetlbfs_mknod(&nop_mnt_idmap, dir, dentry, mode | S_IFREG, 0);
1066 }
1067
1068 static int hugetlbfs_tmpfile(struct mnt_idmap *idmap,
1069                              struct inode *dir, struct file *file,
1070                              umode_t mode)
1071 {
1072         struct inode *inode;
1073
1074         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode | S_IFREG, 0);
1075         if (!inode)
1076                 return -ENOSPC;
1077         inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
1078         d_tmpfile(file, inode);
1079         return finish_open_simple(file, 0);
1080 }
1081
1082 static int hugetlbfs_symlink(struct mnt_idmap *idmap,
1083                              struct inode *dir, struct dentry *dentry,
1084                              const char *symname)
1085 {
1086         struct inode *inode;
1087         int error = -ENOSPC;
1088
1089         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
1090         if (inode) {
1091                 int l = strlen(symname)+1;
1092                 error = page_symlink(inode, symname, l);
1093                 if (!error) {
1094                         d_instantiate(dentry, inode);
1095                         dget(dentry);
1096                 } else
1097                         iput(inode);
1098         }
1099         inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
1100
1101         return error;
1102 }
1103
1104 #ifdef CONFIG_MIGRATION
1105 static int hugetlbfs_migrate_folio(struct address_space *mapping,
1106                                 struct folio *dst, struct folio *src,
1107                                 enum migrate_mode mode)
1108 {
1109         int rc;
1110
1111         rc = migrate_huge_page_move_mapping(mapping, dst, src);
1112         if (rc != MIGRATEPAGE_SUCCESS)
1113                 return rc;
1114
1115         if (hugetlb_folio_subpool(src)) {
1116                 hugetlb_set_folio_subpool(dst,
1117                                         hugetlb_folio_subpool(src));
1118                 hugetlb_set_folio_subpool(src, NULL);
1119         }
1120
1121         if (mode != MIGRATE_SYNC_NO_COPY)
1122                 folio_migrate_copy(dst, src);
1123         else
1124                 folio_migrate_flags(dst, src);
1125
1126         return MIGRATEPAGE_SUCCESS;
1127 }
1128 #else
1129 #define hugetlbfs_migrate_folio NULL
1130 #endif
1131
1132 static int hugetlbfs_error_remove_page(struct address_space *mapping,
1133                                 struct page *page)
1134 {
1135         return 0;
1136 }
1137
1138 /*
1139  * Display the mount options in /proc/mounts.
1140  */
1141 static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root)
1142 {
1143         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(root->d_sb);
1144         struct hugepage_subpool *spool = sbinfo->spool;
1145         unsigned long hpage_size = huge_page_size(sbinfo->hstate);
1146         unsigned hpage_shift = huge_page_shift(sbinfo->hstate);
1147         char mod;
1148
1149         if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
1150                 seq_printf(m, ",uid=%u",
1151                            from_kuid_munged(&init_user_ns, sbinfo->uid));
1152         if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
1153                 seq_printf(m, ",gid=%u",
1154                            from_kgid_munged(&init_user_ns, sbinfo->gid));
1155         if (sbinfo->mode != 0755)
1156                 seq_printf(m, ",mode=%o", sbinfo->mode);
1157         if (sbinfo->max_inodes != -1)
1158                 seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes);
1159
1160         hpage_size /= 1024;
1161         mod = 'K';
1162         if (hpage_size >= 1024) {
1163                 hpage_size /= 1024;
1164                 mod = 'M';
1165         }
1166         seq_printf(m, ",pagesize=%lu%c", hpage_size, mod);
1167         if (spool) {
1168                 if (spool->max_hpages != -1)
1169                         seq_printf(m, ",size=%llu",
1170                                    (unsigned long long)spool->max_hpages << hpage_shift);
1171                 if (spool->min_hpages != -1)
1172                         seq_printf(m, ",min_size=%llu",
1173                                    (unsigned long long)spool->min_hpages << hpage_shift);
1174         }
1175         return 0;
1176 }
1177
1178 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1179 {
1180         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
1181         struct hstate *h = hstate_inode(d_inode(dentry));
1182         u64 id = huge_encode_dev(dentry->d_sb->s_dev);
1183
1184         buf->f_fsid = u64_to_fsid(id);
1185         buf->f_type = HUGETLBFS_MAGIC;
1186         buf->f_bsize = huge_page_size(h);
1187         if (sbinfo) {
1188                 spin_lock(&sbinfo->stat_lock);
1189                 /* If no limits set, just report 0 or -1 for max/free/used
1190                  * blocks, like simple_statfs() */
1191                 if (sbinfo->spool) {
1192                         long free_pages;
1193
1194                         spin_lock_irq(&sbinfo->spool->lock);
1195                         buf->f_blocks = sbinfo->spool->max_hpages;
1196                         free_pages = sbinfo->spool->max_hpages
1197                                 - sbinfo->spool->used_hpages;
1198                         buf->f_bavail = buf->f_bfree = free_pages;
1199                         spin_unlock_irq(&sbinfo->spool->lock);
1200                         buf->f_files = sbinfo->max_inodes;
1201                         buf->f_ffree = sbinfo->free_inodes;
1202                 }
1203                 spin_unlock(&sbinfo->stat_lock);
1204         }
1205         buf->f_namelen = NAME_MAX;
1206         return 0;
1207 }
1208
1209 static void hugetlbfs_put_super(struct super_block *sb)
1210 {
1211         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
1212
1213         if (sbi) {
1214                 sb->s_fs_info = NULL;
1215
1216                 if (sbi->spool)
1217                         hugepage_put_subpool(sbi->spool);
1218
1219                 kfree(sbi);
1220         }
1221 }
1222
1223 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1224 {
1225         if (sbinfo->free_inodes >= 0) {
1226                 spin_lock(&sbinfo->stat_lock);
1227                 if (unlikely(!sbinfo->free_inodes)) {
1228                         spin_unlock(&sbinfo->stat_lock);
1229                         return 0;
1230                 }
1231                 sbinfo->free_inodes--;
1232                 spin_unlock(&sbinfo->stat_lock);
1233         }
1234
1235         return 1;
1236 }
1237
1238 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1239 {
1240         if (sbinfo->free_inodes >= 0) {
1241                 spin_lock(&sbinfo->stat_lock);
1242                 sbinfo->free_inodes++;
1243                 spin_unlock(&sbinfo->stat_lock);
1244         }
1245 }
1246
1247
1248 static struct kmem_cache *hugetlbfs_inode_cachep;
1249
1250 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
1251 {
1252         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
1253         struct hugetlbfs_inode_info *p;
1254
1255         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
1256                 return NULL;
1257         p = alloc_inode_sb(sb, hugetlbfs_inode_cachep, GFP_KERNEL);
1258         if (unlikely(!p)) {
1259                 hugetlbfs_inc_free_inodes(sbinfo);
1260                 return NULL;
1261         }
1262         return &p->vfs_inode;
1263 }
1264
1265 static void hugetlbfs_free_inode(struct inode *inode)
1266 {
1267         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
1268 }
1269
1270 static void hugetlbfs_destroy_inode(struct inode *inode)
1271 {
1272         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
1273 }
1274
1275 static const struct address_space_operations hugetlbfs_aops = {
1276         .write_begin    = hugetlbfs_write_begin,
1277         .write_end      = hugetlbfs_write_end,
1278         .dirty_folio    = noop_dirty_folio,
1279         .migrate_folio  = hugetlbfs_migrate_folio,
1280         .error_remove_page      = hugetlbfs_error_remove_page,
1281 };
1282
1283
1284 static void init_once(void *foo)
1285 {
1286         struct hugetlbfs_inode_info *ei = foo;
1287
1288         inode_init_once(&ei->vfs_inode);
1289 }
1290
1291 const struct file_operations hugetlbfs_file_operations = {
1292         .read_iter              = hugetlbfs_read_iter,
1293         .mmap                   = hugetlbfs_file_mmap,
1294         .fsync                  = noop_fsync,
1295         .get_unmapped_area      = hugetlb_get_unmapped_area,
1296         .llseek                 = default_llseek,
1297         .fallocate              = hugetlbfs_fallocate,
1298 };
1299
1300 static const struct inode_operations hugetlbfs_dir_inode_operations = {
1301         .create         = hugetlbfs_create,
1302         .lookup         = simple_lookup,
1303         .link           = simple_link,
1304         .unlink         = simple_unlink,
1305         .symlink        = hugetlbfs_symlink,
1306         .mkdir          = hugetlbfs_mkdir,
1307         .rmdir          = simple_rmdir,
1308         .mknod          = hugetlbfs_mknod,
1309         .rename         = simple_rename,
1310         .setattr        = hugetlbfs_setattr,
1311         .tmpfile        = hugetlbfs_tmpfile,
1312 };
1313
1314 static const struct inode_operations hugetlbfs_inode_operations = {
1315         .setattr        = hugetlbfs_setattr,
1316 };
1317
1318 static const struct super_operations hugetlbfs_ops = {
1319         .alloc_inode    = hugetlbfs_alloc_inode,
1320         .free_inode     = hugetlbfs_free_inode,
1321         .destroy_inode  = hugetlbfs_destroy_inode,
1322         .evict_inode    = hugetlbfs_evict_inode,
1323         .statfs         = hugetlbfs_statfs,
1324         .put_super      = hugetlbfs_put_super,
1325         .show_options   = hugetlbfs_show_options,
1326 };
1327
1328 /*
1329  * Convert size option passed from command line to number of huge pages
1330  * in the pool specified by hstate.  Size option could be in bytes
1331  * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1332  */
1333 static long
1334 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1335                          enum hugetlbfs_size_type val_type)
1336 {
1337         if (val_type == NO_SIZE)
1338                 return -1;
1339
1340         if (val_type == SIZE_PERCENT) {
1341                 size_opt <<= huge_page_shift(h);
1342                 size_opt *= h->max_huge_pages;
1343                 do_div(size_opt, 100);
1344         }
1345
1346         size_opt >>= huge_page_shift(h);
1347         return size_opt;
1348 }
1349
1350 /*
1351  * Parse one mount parameter.
1352  */
1353 static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1354 {
1355         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1356         struct fs_parse_result result;
1357         char *rest;
1358         unsigned long ps;
1359         int opt;
1360
1361         opt = fs_parse(fc, hugetlb_fs_parameters, param, &result);
1362         if (opt < 0)
1363                 return opt;
1364
1365         switch (opt) {
1366         case Opt_uid:
1367                 ctx->uid = make_kuid(current_user_ns(), result.uint_32);
1368                 if (!uid_valid(ctx->uid))
1369                         goto bad_val;
1370                 return 0;
1371
1372         case Opt_gid:
1373                 ctx->gid = make_kgid(current_user_ns(), result.uint_32);
1374                 if (!gid_valid(ctx->gid))
1375                         goto bad_val;
1376                 return 0;
1377
1378         case Opt_mode:
1379                 ctx->mode = result.uint_32 & 01777U;
1380                 return 0;
1381
1382         case Opt_size:
1383                 /* memparse() will accept a K/M/G without a digit */
1384                 if (!param->string || !isdigit(param->string[0]))
1385                         goto bad_val;
1386                 ctx->max_size_opt = memparse(param->string, &rest);
1387                 ctx->max_val_type = SIZE_STD;
1388                 if (*rest == '%')
1389                         ctx->max_val_type = SIZE_PERCENT;
1390                 return 0;
1391
1392         case Opt_nr_inodes:
1393                 /* memparse() will accept a K/M/G without a digit */
1394                 if (!param->string || !isdigit(param->string[0]))
1395                         goto bad_val;
1396                 ctx->nr_inodes = memparse(param->string, &rest);
1397                 return 0;
1398
1399         case Opt_pagesize:
1400                 ps = memparse(param->string, &rest);
1401                 ctx->hstate = size_to_hstate(ps);
1402                 if (!ctx->hstate) {
1403                         pr_err("Unsupported page size %lu MB\n", ps / SZ_1M);
1404                         return -EINVAL;
1405                 }
1406                 return 0;
1407
1408         case Opt_min_size:
1409                 /* memparse() will accept a K/M/G without a digit */
1410                 if (!param->string || !isdigit(param->string[0]))
1411                         goto bad_val;
1412                 ctx->min_size_opt = memparse(param->string, &rest);
1413                 ctx->min_val_type = SIZE_STD;
1414                 if (*rest == '%')
1415                         ctx->min_val_type = SIZE_PERCENT;
1416                 return 0;
1417
1418         default:
1419                 return -EINVAL;
1420         }
1421
1422 bad_val:
1423         return invalfc(fc, "Bad value '%s' for mount option '%s'\n",
1424                       param->string, param->key);
1425 }
1426
1427 /*
1428  * Validate the parsed options.
1429  */
1430 static int hugetlbfs_validate(struct fs_context *fc)
1431 {
1432         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1433
1434         /*
1435          * Use huge page pool size (in hstate) to convert the size
1436          * options to number of huge pages.  If NO_SIZE, -1 is returned.
1437          */
1438         ctx->max_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1439                                                    ctx->max_size_opt,
1440                                                    ctx->max_val_type);
1441         ctx->min_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1442                                                    ctx->min_size_opt,
1443                                                    ctx->min_val_type);
1444
1445         /*
1446          * If max_size was specified, then min_size must be smaller
1447          */
1448         if (ctx->max_val_type > NO_SIZE &&
1449             ctx->min_hpages > ctx->max_hpages) {
1450                 pr_err("Minimum size can not be greater than maximum size\n");
1451                 return -EINVAL;
1452         }
1453
1454         return 0;
1455 }
1456
1457 static int
1458 hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc)
1459 {
1460         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1461         struct hugetlbfs_sb_info *sbinfo;
1462
1463         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1464         if (!sbinfo)
1465                 return -ENOMEM;
1466         sb->s_fs_info = sbinfo;
1467         spin_lock_init(&sbinfo->stat_lock);
1468         sbinfo->hstate          = ctx->hstate;
1469         sbinfo->max_inodes      = ctx->nr_inodes;
1470         sbinfo->free_inodes     = ctx->nr_inodes;
1471         sbinfo->spool           = NULL;
1472         sbinfo->uid             = ctx->uid;
1473         sbinfo->gid             = ctx->gid;
1474         sbinfo->mode            = ctx->mode;
1475
1476         /*
1477          * Allocate and initialize subpool if maximum or minimum size is
1478          * specified.  Any needed reservations (for minimum size) are taken
1479          * when the subpool is created.
1480          */
1481         if (ctx->max_hpages != -1 || ctx->min_hpages != -1) {
1482                 sbinfo->spool = hugepage_new_subpool(ctx->hstate,
1483                                                      ctx->max_hpages,
1484                                                      ctx->min_hpages);
1485                 if (!sbinfo->spool)
1486                         goto out_free;
1487         }
1488         sb->s_maxbytes = MAX_LFS_FILESIZE;
1489         sb->s_blocksize = huge_page_size(ctx->hstate);
1490         sb->s_blocksize_bits = huge_page_shift(ctx->hstate);
1491         sb->s_magic = HUGETLBFS_MAGIC;
1492         sb->s_op = &hugetlbfs_ops;
1493         sb->s_time_gran = 1;
1494
1495         /*
1496          * Due to the special and limited functionality of hugetlbfs, it does
1497          * not work well as a stacking filesystem.
1498          */
1499         sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
1500         sb->s_root = d_make_root(hugetlbfs_get_root(sb, ctx));
1501         if (!sb->s_root)
1502                 goto out_free;
1503         return 0;
1504 out_free:
1505         kfree(sbinfo->spool);
1506         kfree(sbinfo);
1507         return -ENOMEM;
1508 }
1509
1510 static int hugetlbfs_get_tree(struct fs_context *fc)
1511 {
1512         int err = hugetlbfs_validate(fc);
1513         if (err)
1514                 return err;
1515         return get_tree_nodev(fc, hugetlbfs_fill_super);
1516 }
1517
1518 static void hugetlbfs_fs_context_free(struct fs_context *fc)
1519 {
1520         kfree(fc->fs_private);
1521 }
1522
1523 static const struct fs_context_operations hugetlbfs_fs_context_ops = {
1524         .free           = hugetlbfs_fs_context_free,
1525         .parse_param    = hugetlbfs_parse_param,
1526         .get_tree       = hugetlbfs_get_tree,
1527 };
1528
1529 static int hugetlbfs_init_fs_context(struct fs_context *fc)
1530 {
1531         struct hugetlbfs_fs_context *ctx;
1532
1533         ctx = kzalloc(sizeof(struct hugetlbfs_fs_context), GFP_KERNEL);
1534         if (!ctx)
1535                 return -ENOMEM;
1536
1537         ctx->max_hpages = -1; /* No limit on size by default */
1538         ctx->nr_inodes  = -1; /* No limit on number of inodes by default */
1539         ctx->uid        = current_fsuid();
1540         ctx->gid        = current_fsgid();
1541         ctx->mode       = 0755;
1542         ctx->hstate     = &default_hstate;
1543         ctx->min_hpages = -1; /* No default minimum size */
1544         ctx->max_val_type = NO_SIZE;
1545         ctx->min_val_type = NO_SIZE;
1546         fc->fs_private = ctx;
1547         fc->ops = &hugetlbfs_fs_context_ops;
1548         return 0;
1549 }
1550
1551 static struct file_system_type hugetlbfs_fs_type = {
1552         .name                   = "hugetlbfs",
1553         .init_fs_context        = hugetlbfs_init_fs_context,
1554         .parameters             = hugetlb_fs_parameters,
1555         .kill_sb                = kill_litter_super,
1556 };
1557
1558 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1559
1560 static int can_do_hugetlb_shm(void)
1561 {
1562         kgid_t shm_group;
1563         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1564         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1565 }
1566
1567 static int get_hstate_idx(int page_size_log)
1568 {
1569         struct hstate *h = hstate_sizelog(page_size_log);
1570
1571         if (!h)
1572                 return -1;
1573         return hstate_index(h);
1574 }
1575
1576 /*
1577  * Note that size should be aligned to proper hugepage size in caller side,
1578  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1579  */
1580 struct file *hugetlb_file_setup(const char *name, size_t size,
1581                                 vm_flags_t acctflag, int creat_flags,
1582                                 int page_size_log)
1583 {
1584         struct inode *inode;
1585         struct vfsmount *mnt;
1586         int hstate_idx;
1587         struct file *file;
1588
1589         hstate_idx = get_hstate_idx(page_size_log);
1590         if (hstate_idx < 0)
1591                 return ERR_PTR(-ENODEV);
1592
1593         mnt = hugetlbfs_vfsmount[hstate_idx];
1594         if (!mnt)
1595                 return ERR_PTR(-ENOENT);
1596
1597         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1598                 struct ucounts *ucounts = current_ucounts();
1599
1600                 if (user_shm_lock(size, ucounts)) {
1601                         pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is obsolete\n",
1602                                 current->comm, current->pid);
1603                         user_shm_unlock(size, ucounts);
1604                 }
1605                 return ERR_PTR(-EPERM);
1606         }
1607
1608         file = ERR_PTR(-ENOSPC);
1609         inode = hugetlbfs_get_inode(mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0);
1610         if (!inode)
1611                 goto out;
1612         if (creat_flags == HUGETLB_SHMFS_INODE)
1613                 inode->i_flags |= S_PRIVATE;
1614
1615         inode->i_size = size;
1616         clear_nlink(inode);
1617
1618         if (!hugetlb_reserve_pages(inode, 0,
1619                         size >> huge_page_shift(hstate_inode(inode)), NULL,
1620                         acctflag))
1621                 file = ERR_PTR(-ENOMEM);
1622         else
1623                 file = alloc_file_pseudo(inode, mnt, name, O_RDWR,
1624                                         &hugetlbfs_file_operations);
1625         if (!IS_ERR(file))
1626                 return file;
1627
1628         iput(inode);
1629 out:
1630         return file;
1631 }
1632
1633 static struct vfsmount *__init mount_one_hugetlbfs(struct hstate *h)
1634 {
1635         struct fs_context *fc;
1636         struct vfsmount *mnt;
1637
1638         fc = fs_context_for_mount(&hugetlbfs_fs_type, SB_KERNMOUNT);
1639         if (IS_ERR(fc)) {
1640                 mnt = ERR_CAST(fc);
1641         } else {
1642                 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1643                 ctx->hstate = h;
1644                 mnt = fc_mount(fc);
1645                 put_fs_context(fc);
1646         }
1647         if (IS_ERR(mnt))
1648                 pr_err("Cannot mount internal hugetlbfs for page size %luK",
1649                        huge_page_size(h) / SZ_1K);
1650         return mnt;
1651 }
1652
1653 static int __init init_hugetlbfs_fs(void)
1654 {
1655         struct vfsmount *mnt;
1656         struct hstate *h;
1657         int error;
1658         int i;
1659
1660         if (!hugepages_supported()) {
1661                 pr_info("disabling because there are no supported hugepage sizes\n");
1662                 return -ENOTSUPP;
1663         }
1664
1665         error = -ENOMEM;
1666         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1667                                         sizeof(struct hugetlbfs_inode_info),
1668                                         0, SLAB_ACCOUNT, init_once);
1669         if (hugetlbfs_inode_cachep == NULL)
1670                 goto out;
1671
1672         error = register_filesystem(&hugetlbfs_fs_type);
1673         if (error)
1674                 goto out_free;
1675
1676         /* default hstate mount is required */
1677         mnt = mount_one_hugetlbfs(&default_hstate);
1678         if (IS_ERR(mnt)) {
1679                 error = PTR_ERR(mnt);
1680                 goto out_unreg;
1681         }
1682         hugetlbfs_vfsmount[default_hstate_idx] = mnt;
1683
1684         /* other hstates are optional */
1685         i = 0;
1686         for_each_hstate(h) {
1687                 if (i == default_hstate_idx) {
1688                         i++;
1689                         continue;
1690                 }
1691
1692                 mnt = mount_one_hugetlbfs(h);
1693                 if (IS_ERR(mnt))
1694                         hugetlbfs_vfsmount[i] = NULL;
1695                 else
1696                         hugetlbfs_vfsmount[i] = mnt;
1697                 i++;
1698         }
1699
1700         return 0;
1701
1702  out_unreg:
1703         (void)unregister_filesystem(&hugetlbfs_fs_type);
1704  out_free:
1705         kmem_cache_destroy(hugetlbfs_inode_cachep);
1706  out:
1707         return error;
1708 }
1709 fs_initcall(init_hugetlbfs_fs)