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         vm_flags_t vm_flags;
 104
 105         /*
 106          * vma address alignment (but not the pgoff alignment) has
 107          * already been checked by prepare_hugepage_range.  If you add
 108          * any error returns here, do so after setting VM_HUGETLB, so
 109          * is_vm_hugetlb_page tests below unmap_region go the right
 110          * way when do_mmap unwinds (may be important on powerpc
 111          * and ia64).
 112          */
 113         vm_flags_set(vma, VM_HUGETLB | VM_DONTEXPAND);
 114         vma->vm_ops = &hugetlb_vm_ops;
 115
 116         ret = seal_check_write(info->seals, vma);
 117         if (ret)
 118                 return ret;
 119
 120         /*
 121          * page based offset in vm_pgoff could be sufficiently large to
 122          * overflow a loff_t when converted to byte offset.  This can
 123          * only happen on architectures where sizeof(loff_t) ==
 124          * sizeof(unsigned long).  So, only check in those instances.
 125          */
 126         if (sizeof(unsigned long) == sizeof(loff_t)) {
 127                 if (vma->vm_pgoff & PGOFF_LOFFT_MAX)
 128                         return -EINVAL;
 129         }
 130
 131         /* must be huge page aligned */
 132         if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
 133                 return -EINVAL;
 134
 135         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
 136         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 137         /* check for overflow */
 138         if (len < vma_len)
 139                 return -EINVAL;
 140
 141         inode_lock(inode);
 142         file_accessed(file);
 143
 144         ret = -ENOMEM;
 145
 146         vm_flags = vma->vm_flags;
 147         /*
 148          * for SHM_HUGETLB, the pages are reserved in the shmget() call so skip
 149          * reserving here. Note: only for SHM hugetlbfs file, the inode
 150          * flag S_PRIVATE is set.
 151          */
 152         if (inode->i_flags & S_PRIVATE)
 153                 vm_flags |= VM_NORESERVE;
 154
 155         if (!hugetlb_reserve_pages(inode,
 156                                 vma->vm_pgoff >> huge_page_order(h),
 157                                 len >> huge_page_shift(h), vma,
 158                                 vm_flags))
 159                 goto out;
 160
 161         ret = 0;
 162         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
 163                 i_size_write(inode, len);
 164 out:
 165         inode_unlock(inode);
 166
 167         return ret;
 168 }
 169
 170 /*
 171  * Called under mmap_write_lock(mm).
 172  */
 173
 174 static unsigned long
 175 hugetlb_get_unmapped_area_bottomup(struct file *file, unsigned long addr,
 176                 unsigned long len, unsigned long pgoff, unsigned long flags)
 177 {
 178         struct hstate *h = hstate_file(file);
 179         struct vm_unmapped_area_info info;
 180
 181         info.flags = 0;
 182         info.length = len;
 183         info.low_limit = current->mm->mmap_base;
 184         info.high_limit = arch_get_mmap_end(addr, len, flags);
 185         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 186         info.align_offset = 0;
 187         return vm_unmapped_area(&info);
 188 }
 189
 190 static unsigned long
 191 hugetlb_get_unmapped_area_topdown(struct file *file, unsigned long addr,
 192                 unsigned long len, unsigned long pgoff, unsigned long flags)
 193 {
 194         struct hstate *h = hstate_file(file);
 195         struct vm_unmapped_area_info info;
 196
 197         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 198         info.length = len;
 199         info.low_limit = PAGE_SIZE;
 200         info.high_limit = arch_get_mmap_base(addr, current->mm->mmap_base);
 201         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 202         info.align_offset = 0;
 203         addr = vm_unmapped_area(&info);
 204
 205         /*
 206          * A failed mmap() very likely causes application failure,
 207          * so fall back to the bottom-up function here. This scenario
 208          * can happen with large stack limits and large mmap()
 209          * allocations.
 210          */
 211         if (unlikely(offset_in_page(addr))) {
 212                 VM_BUG_ON(addr != -ENOMEM);
 213                 info.flags = 0;
 214                 info.low_limit = current->mm->mmap_base;
 215                 info.high_limit = arch_get_mmap_end(addr, len, flags);
 216                 addr = vm_unmapped_area(&info);
 217         }
 218
 219         return addr;
 220 }
 221
 222 unsigned long
 223 generic_hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 224                                   unsigned long len, unsigned long pgoff,
 225                                   unsigned long flags)
 226 {
 227         struct mm_struct *mm = current->mm;
 228         struct vm_area_struct *vma;
 229         struct hstate *h = hstate_file(file);
 230         const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags);
 231
 232         if (len & ~huge_page_mask(h))
 233                 return -EINVAL;
 234         if (len > TASK_SIZE)
 235                 return -ENOMEM;
 236
 237         if (flags & MAP_FIXED) {
 238                 if (prepare_hugepage_range(file, addr, len))
 239                         return -EINVAL;
 240                 return addr;
 241         }
 242
 243         if (addr) {
 244                 addr = ALIGN(addr, huge_page_size(h));
 245                 vma = find_vma(mm, addr);
 246                 if (mmap_end - len >= addr &&
 247                     (!vma || addr + len <= vm_start_gap(vma)))
 248                         return addr;
 249         }
 250
 251         /*
 252          * Use mm->get_unmapped_area value as a hint to use topdown routine.
 253          * If architectures have special needs, they should define their own
 254          * version of hugetlb_get_unmapped_area.
 255          */
 256         if (mm->get_unmapped_area == arch_get_unmapped_area_topdown)
 257                 return hugetlb_get_unmapped_area_topdown(file, addr, len,
 258                                 pgoff, flags);
 259         return hugetlb_get_unmapped_area_bottomup(file, addr, len,
 260                         pgoff, flags);
 261 }
 262
 263 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 264 static unsigned long
 265 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 266                           unsigned long len, unsigned long pgoff,
 267                           unsigned long flags)
 268 {
 269         return generic_hugetlb_get_unmapped_area(file, addr, len, pgoff, flags);
 270 }
 271 #endif
 272
 273 /*
 274  * Someone wants to read @bytes from a HWPOISON hugetlb @page from @offset.
 275  * Returns the maximum number of bytes one can read without touching the 1st raw
 276  * HWPOISON subpage.
 277  *
 278  * The implementation borrows the iteration logic from copy_page_to_iter*.
 279  */
 280 static size_t adjust_range_hwpoison(struct page *page, size_t offset, size_t bytes)
 281 {
 282         size_t n = 0;
 283         size_t res = 0;
 284
 285         /* First subpage to start the loop. */
 286         page = nth_page(page, offset / PAGE_SIZE);
 287         offset %= PAGE_SIZE;
 288         while (1) {
 289                 if (is_raw_hwpoison_page_in_hugepage(page))
 290                         break;
 291
 292                 /* Safe to read n bytes without touching HWPOISON subpage. */
 293                 n = min(bytes, (size_t)PAGE_SIZE - offset);
 294                 res += n;
 295                 bytes -= n;
 296                 if (!bytes || !n)
 297                         break;
 298                 offset += n;
 299                 if (offset == PAGE_SIZE) {
 300                         page = nth_page(page, 1);
 301                         offset = 0;
 302                 }
 303         }
 304
 305         return res;
 306 }
 307
 308 /*
 309  * Support for read() - Find the page attached to f_mapping and copy out the
 310  * data. This provides functionality similar to filemap_read().
 311  */
 312 static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
 313 {
 314         struct file *file = iocb->ki_filp;
 315         struct hstate *h = hstate_file(file);
 316         struct address_space *mapping = file->f_mapping;
 317         struct inode *inode = mapping->host;
 318         unsigned long index = iocb->ki_pos >> huge_page_shift(h);
 319         unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
 320         unsigned long end_index;
 321         loff_t isize;
 322         ssize_t retval = 0;
 323
 324         while (iov_iter_count(to)) {
 325                 struct folio *folio;
 326                 size_t nr, copied, want;
 327
 328                 /* nr is the maximum number of bytes to copy from this page */
 329                 nr = huge_page_size(h);
 330                 isize = i_size_read(inode);
 331                 if (!isize)
 332                         break;
 333                 end_index = (isize - 1) >> huge_page_shift(h);
 334                 if (index > end_index)
 335                         break;
 336                 if (index == end_index) {
 337                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
 338                         if (nr <= offset)
 339                                 break;
 340                 }
 341                 nr = nr - offset;
 342
 343                 /* Find the folio */
 344                 folio = filemap_lock_hugetlb_folio(h, mapping, index);
 345                 if (IS_ERR(folio)) {
 346                         /*
 347                          * We have a HOLE, zero out the user-buffer for the
 348                          * length of the hole or request.
 349                          */
 350                         copied = iov_iter_zero(nr, to);
 351                 } else {
 352                         folio_unlock(folio);
 353
 354                         if (!folio_test_hwpoison(folio))
 355                                 want = nr;
 356                         else {
 357                                 /*
 358                                  * Adjust how many bytes safe to read without
 359                                  * touching the 1st raw HWPOISON subpage after
 360                                  * offset.
 361                                  */
 362                                 want = adjust_range_hwpoison(&folio->page, offset, nr);
 363                                 if (want == 0) {
 364                                         folio_put(folio);
 365                                         retval = -EIO;
 366                                         break;
 367                                 }
 368                         }
 369
 370                         /*
 371                          * We have the folio, copy it to user space buffer.
 372                          */
 373                         copied = copy_folio_to_iter(folio, offset, want, to);
 374                         folio_put(folio);
 375                 }
 376                 offset += copied;
 377                 retval += copied;
 378                 if (copied != nr && iov_iter_count(to)) {
 379                         if (!retval)
 380                                 retval = -EFAULT;
 381                         break;
 382                 }
 383                 index += offset >> huge_page_shift(h);
 384                 offset &= ~huge_page_mask(h);
 385         }
 386         iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
 387         return retval;
 388 }
 389
 390 static int hugetlbfs_write_begin(struct file *file,
 391                         struct address_space *mapping,
 392                         loff_t pos, unsigned len,
 393                         struct page **pagep, void **fsdata)
 394 {
 395         return -EINVAL;
 396 }
 397
 398 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
 399                         loff_t pos, unsigned len, unsigned copied,
 400                         struct page *page, void *fsdata)
 401 {
 402         BUG();
 403         return -EINVAL;
 404 }
 405
 406 static void hugetlb_delete_from_page_cache(struct folio *folio)
 407 {
 408         folio_clear_dirty(folio);
 409         folio_clear_uptodate(folio);
 410         filemap_remove_folio(folio);
 411 }
 412
 413 /*
 414  * Called with i_mmap_rwsem held for inode based vma maps.  This makes
 415  * sure vma (and vm_mm) will not go away.  We also hold the hugetlb fault
 416  * mutex for the page in the mapping.  So, we can not race with page being
 417  * faulted into the vma.
 418  */
 419 static bool hugetlb_vma_maps_page(struct vm_area_struct *vma,
 420                                 unsigned long addr, struct page *page)
 421 {
 422         pte_t *ptep, pte;
 423
 424         ptep = hugetlb_walk(vma, addr, huge_page_size(hstate_vma(vma)));
 425         if (!ptep)
 426                 return false;
 427
 428         pte = huge_ptep_get(ptep);
 429         if (huge_pte_none(pte) || !pte_present(pte))
 430                 return false;
 431
 432         if (pte_page(pte) == page)
 433                 return true;
 434
 435         return false;
 436 }
 437
 438 /*
 439  * Can vma_offset_start/vma_offset_end overflow on 32-bit arches?
 440  * No, because the interval tree returns us only those vmas
 441  * which overlap the truncated area starting at pgoff,
 442  * and no vma on a 32-bit arch can span beyond the 4GB.
 443  */
 444 static unsigned long vma_offset_start(struct vm_area_struct *vma, pgoff_t start)
 445 {
 446         unsigned long offset = 0;
 447
 448         if (vma->vm_pgoff < start)
 449                 offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
 450
 451         return vma->vm_start + offset;
 452 }
 453
 454 static unsigned long vma_offset_end(struct vm_area_struct *vma, pgoff_t end)
 455 {
 456         unsigned long t_end;
 457
 458         if (!end)
 459                 return vma->vm_end;
 460
 461         t_end = ((end - vma->vm_pgoff) << PAGE_SHIFT) + vma->vm_start;
 462         if (t_end > vma->vm_end)
 463                 t_end = vma->vm_end;
 464         return t_end;
 465 }
 466
 467 /*
 468  * Called with hugetlb fault mutex held.  Therefore, no more mappings to
 469  * this folio can be created while executing the routine.
 470  */
 471 static void hugetlb_unmap_file_folio(struct hstate *h,
 472                                         struct address_space *mapping,
 473                                         struct folio *folio, pgoff_t index)
 474 {
 475         struct rb_root_cached *root = &mapping->i_mmap;
 476         struct hugetlb_vma_lock *vma_lock;
 477         struct page *page = &folio->page;
 478         struct vm_area_struct *vma;
 479         unsigned long v_start;
 480         unsigned long v_end;
 481         pgoff_t start, end;
 482
 483         start = index * pages_per_huge_page(h);
 484         end = (index + 1) * pages_per_huge_page(h);
 485
 486         i_mmap_lock_write(mapping);
 487 retry:
 488         vma_lock = NULL;
 489         vma_interval_tree_foreach(vma, root, start, end - 1) {
 490                 v_start = vma_offset_start(vma, start);
 491                 v_end = vma_offset_end(vma, end);
 492
 493                 if (!hugetlb_vma_maps_page(vma, v_start, page))
 494                         continue;
 495
 496                 if (!hugetlb_vma_trylock_write(vma)) {
 497                         vma_lock = vma->vm_private_data;
 498                         /*
 499                          * If we can not get vma lock, we need to drop
 500                          * immap_sema and take locks in order.  First,
 501                          * take a ref on the vma_lock structure so that
 502                          * we can be guaranteed it will not go away when
 503                          * dropping immap_sema.
 504                          */
 505                         kref_get(&vma_lock->refs);
 506                         break;
 507                 }
 508
 509                 unmap_hugepage_range(vma, v_start, v_end, NULL,
 510                                      ZAP_FLAG_DROP_MARKER);
 511                 hugetlb_vma_unlock_write(vma);
 512         }
 513
 514         i_mmap_unlock_write(mapping);
 515
 516         if (vma_lock) {
 517                 /*
 518                  * Wait on vma_lock.  We know it is still valid as we have
 519                  * a reference.  We must 'open code' vma locking as we do
 520                  * not know if vma_lock is still attached to vma.
 521                  */
 522                 down_write(&vma_lock->rw_sema);
 523                 i_mmap_lock_write(mapping);
 524
 525                 vma = vma_lock->vma;
 526                 if (!vma) {
 527                         /*
 528                          * If lock is no longer attached to vma, then just
 529                          * unlock, drop our reference and retry looking for
 530                          * other vmas.
 531                          */
 532                         up_write(&vma_lock->rw_sema);
 533                         kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
 534                         goto retry;
 535                 }
 536
 537                 /*
 538                  * vma_lock is still attached to vma.  Check to see if vma
 539                  * still maps page and if so, unmap.
 540                  */
 541                 v_start = vma_offset_start(vma, start);
 542                 v_end = vma_offset_end(vma, end);
 543                 if (hugetlb_vma_maps_page(vma, v_start, page))
 544                         unmap_hugepage_range(vma, v_start, v_end, NULL,
 545                                              ZAP_FLAG_DROP_MARKER);
 546
 547                 kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
 548                 hugetlb_vma_unlock_write(vma);
 549
 550                 goto retry;
 551         }
 552 }
 553
 554 static void
 555 hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end,
 556                       zap_flags_t zap_flags)
 557 {
 558         struct vm_area_struct *vma;
 559
 560         /*
 561          * end == 0 indicates that the entire range after start should be
 562          * unmapped.  Note, end is exclusive, whereas the interval tree takes
 563          * an inclusive "last".
 564          */
 565         vma_interval_tree_foreach(vma, root, start, end ? end - 1 : ULONG_MAX) {
 566                 unsigned long v_start;
 567                 unsigned long v_end;
 568
 569                 if (!hugetlb_vma_trylock_write(vma))
 570                         continue;
 571
 572                 v_start = vma_offset_start(vma, start);
 573                 v_end = vma_offset_end(vma, end);
 574
 575                 unmap_hugepage_range(vma, v_start, v_end, NULL, zap_flags);
 576
 577                 /*
 578                  * Note that vma lock only exists for shared/non-private
 579                  * vmas.  Therefore, lock is not held when calling
 580                  * unmap_hugepage_range for private vmas.
 581                  */
 582                 hugetlb_vma_unlock_write(vma);
 583         }
 584 }
 585
 586 /*
 587  * Called with hugetlb fault mutex held.
 588  * Returns true if page was actually removed, false otherwise.
 589  */
 590 static bool remove_inode_single_folio(struct hstate *h, struct inode *inode,
 591                                         struct address_space *mapping,
 592                                         struct folio *folio, pgoff_t index,
 593                                         bool truncate_op)
 594 {
 595         bool ret = false;
 596
 597         /*
 598          * If folio is mapped, it was faulted in after being
 599          * unmapped in caller.  Unmap (again) while holding
 600          * the fault mutex.  The mutex will prevent faults
 601          * until we finish removing the folio.
 602          */
 603         if (unlikely(folio_mapped(folio)))
 604                 hugetlb_unmap_file_folio(h, mapping, folio, index);
 605
 606         folio_lock(folio);
 607         /*
 608          * We must remove the folio from page cache before removing
 609          * the region/ reserve map (hugetlb_unreserve_pages).  In
 610          * rare out of memory conditions, removal of the region/reserve
 611          * map could fail.  Correspondingly, the subpool and global
 612          * reserve usage count can need to be adjusted.
 613          */
 614         VM_BUG_ON_FOLIO(folio_test_hugetlb_restore_reserve(folio), folio);
 615         hugetlb_delete_from_page_cache(folio);
 616         ret = true;
 617         if (!truncate_op) {
 618                 if (unlikely(hugetlb_unreserve_pages(inode, index,
 619                                                         index + 1, 1)))
 620                         hugetlb_fix_reserve_counts(inode);
 621         }
 622
 623         folio_unlock(folio);
 624         return ret;
 625 }
 626
 627 /*
 628  * remove_inode_hugepages handles two distinct cases: truncation and hole
 629  * punch.  There are subtle differences in operation for each case.
 630  *
 631  * truncation is indicated by end of range being LLONG_MAX
 632  *      In this case, we first scan the range and release found pages.
 633  *      After releasing pages, hugetlb_unreserve_pages cleans up region/reserve
 634  *      maps and global counts.  Page faults can race with truncation.
 635  *      During faults, hugetlb_no_page() checks i_size before page allocation,
 636  *      and again after obtaining page table lock.  It will 'back out'
 637  *      allocations in the truncated range.
 638  * hole punch is indicated if end is not LLONG_MAX
 639  *      In the hole punch case we scan the range and release found pages.
 640  *      Only when releasing a page is the associated region/reserve map
 641  *      deleted.  The region/reserve map for ranges without associated
 642  *      pages are not modified.  Page faults can race with hole punch.
 643  *      This is indicated if we find a mapped page.
 644  * Note: If the passed end of range value is beyond the end of file, but
 645  * not LLONG_MAX this routine still performs a hole punch operation.
 646  */
 647 static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
 648                                    loff_t lend)
 649 {
 650         struct hstate *h = hstate_inode(inode);
 651         struct address_space *mapping = &inode->i_data;
 652         const pgoff_t end = lend >> PAGE_SHIFT;
 653         struct folio_batch fbatch;
 654         pgoff_t next, index;
 655         int i, freed = 0;
 656         bool truncate_op = (lend == LLONG_MAX);
 657
 658         folio_batch_init(&fbatch);
 659         next = lstart >> PAGE_SHIFT;
 660         while (filemap_get_folios(mapping, &next, end - 1, &fbatch)) {
 661                 for (i = 0; i < folio_batch_count(&fbatch); ++i) {
 662                         struct folio *folio = fbatch.folios[i];
 663                         u32 hash = 0;
 664
 665                         index = folio->index >> huge_page_order(h);
 666                         hash = hugetlb_fault_mutex_hash(mapping, index);
 667                         mutex_lock(&hugetlb_fault_mutex_table[hash]);
 668
 669                         /*
 670                          * Remove folio that was part of folio_batch.
 671                          */
 672                         if (remove_inode_single_folio(h, inode, mapping, folio,
 673                                                         index, truncate_op))
 674                                 freed++;
 675
 676                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 677                 }
 678                 folio_batch_release(&fbatch);
 679                 cond_resched();
 680         }
 681
 682         if (truncate_op)
 683                 (void)hugetlb_unreserve_pages(inode,
 684                                 lstart >> huge_page_shift(h),
 685                                 LONG_MAX, freed);
 686 }
 687
 688 static void hugetlbfs_evict_inode(struct inode *inode)
 689 {
 690         struct resv_map *resv_map;
 691
 692         remove_inode_hugepages(inode, 0, LLONG_MAX);
 693
 694         /*
 695          * Get the resv_map from the address space embedded in the inode.
 696          * This is the address space which points to any resv_map allocated
 697          * at inode creation time.  If this is a device special inode,
 698          * i_mapping may not point to the original address space.
 699          */
 700         resv_map = (struct resv_map *)(&inode->i_data)->i_private_data;
 701         /* Only regular and link inodes have associated reserve maps */
 702         if (resv_map)
 703                 resv_map_release(&resv_map->refs);
 704         clear_inode(inode);
 705 }
 706
 707 static void hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 708 {
 709         pgoff_t pgoff;
 710         struct address_space *mapping = inode->i_mapping;
 711         struct hstate *h = hstate_inode(inode);
 712
 713         BUG_ON(offset & ~huge_page_mask(h));
 714         pgoff = offset >> PAGE_SHIFT;
 715
 716         i_size_write(inode, offset);
 717         i_mmap_lock_write(mapping);
 718         if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
 719                 hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0,
 720                                       ZAP_FLAG_DROP_MARKER);
 721         i_mmap_unlock_write(mapping);
 722         remove_inode_hugepages(inode, offset, LLONG_MAX);
 723 }
 724
 725 static void hugetlbfs_zero_partial_page(struct hstate *h,
 726                                         struct address_space *mapping,
 727                                         loff_t start,
 728                                         loff_t end)
 729 {
 730         pgoff_t idx = start >> huge_page_shift(h);
 731         struct folio *folio;
 732
 733         folio = filemap_lock_hugetlb_folio(h, mapping, idx);
 734         if (IS_ERR(folio))
 735                 return;
 736
 737         start = start & ~huge_page_mask(h);
 738         end = end & ~huge_page_mask(h);
 739         if (!end)
 740                 end = huge_page_size(h);
 741
 742         folio_zero_segment(folio, (size_t)start, (size_t)end);
 743
 744         folio_unlock(folio);
 745         folio_put(folio);
 746 }
 747
 748 static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
 749 {
 750         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 751         struct address_space *mapping = inode->i_mapping;
 752         struct hstate *h = hstate_inode(inode);
 753         loff_t hpage_size = huge_page_size(h);
 754         loff_t hole_start, hole_end;
 755
 756         /*
 757          * hole_start and hole_end indicate the full pages within the hole.
 758          */
 759         hole_start = round_up(offset, hpage_size);
 760         hole_end = round_down(offset + len, hpage_size);
 761
 762         inode_lock(inode);
 763
 764         /* protected by i_rwsem */
 765         if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) {
 766                 inode_unlock(inode);
 767                 return -EPERM;
 768         }
 769
 770         i_mmap_lock_write(mapping);
 771
 772         /* If range starts before first full page, zero partial page. */
 773         if (offset < hole_start)
 774                 hugetlbfs_zero_partial_page(h, mapping,
 775                                 offset, min(offset + len, hole_start));
 776
 777         /* Unmap users of full pages in the hole. */
 778         if (hole_end > hole_start) {
 779                 if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
 780                         hugetlb_vmdelete_list(&mapping->i_mmap,
 781                                               hole_start >> PAGE_SHIFT,
 782                                               hole_end >> PAGE_SHIFT, 0);
 783         }
 784
 785         /* If range extends beyond last full page, zero partial page. */
 786         if ((offset + len) > hole_end && (offset + len) > hole_start)
 787                 hugetlbfs_zero_partial_page(h, mapping,
 788                                 hole_end, offset + len);
 789
 790         i_mmap_unlock_write(mapping);
 791
 792         /* Remove full pages from the file. */
 793         if (hole_end > hole_start)
 794                 remove_inode_hugepages(inode, hole_start, hole_end);
 795
 796         inode_unlock(inode);
 797
 798         return 0;
 799 }
 800
 801 static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
 802                                 loff_t len)
 803 {
 804         struct inode *inode = file_inode(file);
 805         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 806         struct address_space *mapping = inode->i_mapping;
 807         struct hstate *h = hstate_inode(inode);
 808         struct vm_area_struct pseudo_vma;
 809         struct mm_struct *mm = current->mm;
 810         loff_t hpage_size = huge_page_size(h);
 811         unsigned long hpage_shift = huge_page_shift(h);
 812         pgoff_t start, index, end;
 813         int error;
 814         u32 hash;
 815
 816         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
 817                 return -EOPNOTSUPP;
 818
 819         if (mode & FALLOC_FL_PUNCH_HOLE)
 820                 return hugetlbfs_punch_hole(inode, offset, len);
 821
 822         /*
 823          * Default preallocate case.
 824          * For this range, start is rounded down and end is rounded up
 825          * as well as being converted to page offsets.
 826          */
 827         start = offset >> hpage_shift;
 828         end = (offset + len + hpage_size - 1) >> hpage_shift;
 829
 830         inode_lock(inode);
 831
 832         /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
 833         error = inode_newsize_ok(inode, offset + len);
 834         if (error)
 835                 goto out;
 836
 837         if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) {
 838                 error = -EPERM;
 839                 goto out;
 840         }
 841
 842         /*
 843          * Initialize a pseudo vma as this is required by the huge page
 844          * allocation routines.
 845          */
 846         vma_init(&pseudo_vma, mm);
 847         vm_flags_init(&pseudo_vma, VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
 848         pseudo_vma.vm_file = file;
 849
 850         for (index = start; index < end; index++) {
 851                 /*
 852                  * This is supposed to be the vaddr where the page is being
 853                  * faulted in, but we have no vaddr here.
 854                  */
 855                 struct folio *folio;
 856                 unsigned long addr;
 857
 858                 cond_resched();
 859
 860                 /*
 861                  * fallocate(2) manpage permits EINTR; we may have been
 862                  * interrupted because we are using up too much memory.
 863                  */
 864                 if (signal_pending(current)) {
 865                         error = -EINTR;
 866                         break;
 867                 }
 868
 869                 /* addr is the offset within the file (zero based) */
 870                 addr = index * hpage_size;
 871
 872                 /* mutex taken here, fault path and hole punch */
 873                 hash = hugetlb_fault_mutex_hash(mapping, index);
 874                 mutex_lock(&hugetlb_fault_mutex_table[hash]);
 875
 876                 /* See if already present in mapping to avoid alloc/free */
 877                 folio = filemap_get_folio(mapping, index << huge_page_order(h));
 878                 if (!IS_ERR(folio)) {
 879                         folio_put(folio);
 880                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 881                         continue;
 882                 }
 883
 884                 /*
 885                  * Allocate folio without setting the avoid_reserve argument.
 886                  * There certainly are no reserves associated with the
 887                  * pseudo_vma.  However, there could be shared mappings with
 888                  * reserves for the file at the inode level.  If we fallocate
 889                  * folios in these areas, we need to consume the reserves
 890                  * to keep reservation accounting consistent.
 891                  */
 892                 folio = alloc_hugetlb_folio(&pseudo_vma, addr, 0);
 893                 if (IS_ERR(folio)) {
 894                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 895                         error = PTR_ERR(folio);
 896                         goto out;
 897                 }
 898                 clear_huge_page(&folio->page, addr, pages_per_huge_page(h));
 899                 __folio_mark_uptodate(folio);
 900                 error = hugetlb_add_to_page_cache(folio, mapping, index);
 901                 if (unlikely(error)) {
 902                         restore_reserve_on_error(h, &pseudo_vma, addr, folio);
 903                         folio_put(folio);
 904                         mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 905                         goto out;
 906                 }
 907
 908                 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 909
 910                 folio_set_hugetlb_migratable(folio);
 911                 /*
 912                  * folio_unlock because locked by hugetlb_add_to_page_cache()
 913                  * folio_put() due to reference from alloc_hugetlb_folio()
 914                  */
 915                 folio_unlock(folio);
 916                 folio_put(folio);
 917         }
 918
 919         if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
 920                 i_size_write(inode, offset + len);
 921         inode_set_ctime_current(inode);
 922 out:
 923         inode_unlock(inode);
 924         return error;
 925 }
 926
 927 static int hugetlbfs_setattr(struct mnt_idmap *idmap,
 928                              struct dentry *dentry, struct iattr *attr)
 929 {
 930         struct inode *inode = d_inode(dentry);
 931         struct hstate *h = hstate_inode(inode);
 932         int error;
 933         unsigned int ia_valid = attr->ia_valid;
 934         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
 935
 936         error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 937         if (error)
 938                 return error;
 939
 940         if (ia_valid & ATTR_SIZE) {
 941                 loff_t oldsize = inode->i_size;
 942                 loff_t newsize = attr->ia_size;
 943
 944                 if (newsize & ~huge_page_mask(h))
 945                         return -EINVAL;
 946                 /* protected by i_rwsem */
 947                 if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
 948                     (newsize > oldsize && (info->seals & F_SEAL_GROW)))
 949                         return -EPERM;
 950                 hugetlb_vmtruncate(inode, newsize);
 951         }
 952
 953         setattr_copy(&nop_mnt_idmap, inode, attr);
 954         mark_inode_dirty(inode);
 955         return 0;
 956 }
 957
 958 static struct inode *hugetlbfs_get_root(struct super_block *sb,
 959                                         struct hugetlbfs_fs_context *ctx)
 960 {
 961         struct inode *inode;
 962
 963         inode = new_inode(sb);
 964         if (inode) {
 965                 inode->i_ino = get_next_ino();
 966                 inode->i_mode = S_IFDIR | ctx->mode;
 967                 inode->i_uid = ctx->uid;
 968                 inode->i_gid = ctx->gid;
 969                 simple_inode_init_ts(inode);
 970                 inode->i_op = &hugetlbfs_dir_inode_operations;
 971                 inode->i_fop = &simple_dir_operations;
 972                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
 973                 inc_nlink(inode);
 974                 lockdep_annotate_inode_mutex_key(inode);
 975         }
 976         return inode;
 977 }
 978
 979 /*
 980  * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
 981  * be taken from reclaim -- unlike regular filesystems. This needs an
 982  * annotation because huge_pmd_share() does an allocation under hugetlb's
 983  * i_mmap_rwsem.
 984  */
 985 static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
 986
 987 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 988                                         struct inode *dir,
 989                                         umode_t mode, dev_t dev)
 990 {
 991         struct inode *inode;
 992         struct resv_map *resv_map = NULL;
 993
 994         /*
 995          * Reserve maps are only needed for inodes that can have associated
 996          * page allocations.
 997          */
 998         if (S_ISREG(mode) || S_ISLNK(mode)) {
 999                 resv_map = resv_map_alloc();
1000                 if (!resv_map)
1001                         return NULL;
1002         }
1003
1004         inode = new_inode(sb);
1005         if (inode) {
1006                 struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
1007
1008                 inode->i_ino = get_next_ino();
1009                 inode_init_owner(&nop_mnt_idmap, inode, dir, mode);
1010                 lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
1011                                 &hugetlbfs_i_mmap_rwsem_key);
1012                 inode->i_mapping->a_ops = &hugetlbfs_aops;
1013                 simple_inode_init_ts(inode);
1014                 inode->i_mapping->i_private_data = resv_map;
1015                 info->seals = F_SEAL_SEAL;
1016                 switch (mode & S_IFMT) {
1017                 default:
1018                         init_special_inode(inode, mode, dev);
1019                         break;
1020                 case S_IFREG:
1021                         inode->i_op = &hugetlbfs_inode_operations;
1022                         inode->i_fop = &hugetlbfs_file_operations;
1023                         break;
1024                 case S_IFDIR:
1025                         inode->i_op = &hugetlbfs_dir_inode_operations;
1026                         inode->i_fop = &simple_dir_operations;
1027
1028                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
1029                         inc_nlink(inode);
1030                         break;
1031                 case S_IFLNK:
1032                         inode->i_op = &page_symlink_inode_operations;
1033                         inode_nohighmem(inode);
1034                         break;
1035                 }
1036                 lockdep_annotate_inode_mutex_key(inode);
1037         } else {
1038                 if (resv_map)
1039                         kref_put(&resv_map->refs, resv_map_release);
1040         }
1041
1042         return inode;
1043 }
1044
1045 /*
1046  * File creation. Allocate an inode, and we're done..
1047  */
1048 static int hugetlbfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
1049                            struct dentry *dentry, umode_t mode, dev_t dev)
1050 {
1051         struct inode *inode;
1052
1053         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
1054         if (!inode)
1055                 return -ENOSPC;
1056         inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
1057         d_instantiate(dentry, inode);
1058         dget(dentry);/* Extra count - pin the dentry in core */
1059         return 0;
1060 }
1061
1062 static int hugetlbfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
1063                            struct dentry *dentry, umode_t mode)
1064 {
1065         int retval = hugetlbfs_mknod(&nop_mnt_idmap, dir, dentry,
1066                                      mode | S_IFDIR, 0);
1067         if (!retval)
1068                 inc_nlink(dir);
1069         return retval;
1070 }
1071
1072 static int hugetlbfs_create(struct mnt_idmap *idmap,
1073                             struct inode *dir, struct dentry *dentry,
1074                             umode_t mode, bool excl)
1075 {
1076         return hugetlbfs_mknod(&nop_mnt_idmap, dir, dentry, mode | S_IFREG, 0);
1077 }
1078
1079 static int hugetlbfs_tmpfile(struct mnt_idmap *idmap,
1080                              struct inode *dir, struct file *file,
1081                              umode_t mode)
1082 {
1083         struct inode *inode;
1084
1085         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode | S_IFREG, 0);
1086         if (!inode)
1087                 return -ENOSPC;
1088         inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
1089         d_tmpfile(file, inode);
1090         return finish_open_simple(file, 0);
1091 }
1092
1093 static int hugetlbfs_symlink(struct mnt_idmap *idmap,
1094                              struct inode *dir, struct dentry *dentry,
1095                              const char *symname)
1096 {
1097         struct inode *inode;
1098         int error = -ENOSPC;
1099
1100         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
1101         if (inode) {
1102                 int l = strlen(symname)+1;
1103                 error = page_symlink(inode, symname, l);
1104                 if (!error) {
1105                         d_instantiate(dentry, inode);
1106                         dget(dentry);
1107                 } else
1108                         iput(inode);
1109         }
1110         inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
1111
1112         return error;
1113 }
1114
1115 #ifdef CONFIG_MIGRATION
1116 static int hugetlbfs_migrate_folio(struct address_space *mapping,
1117                                 struct folio *dst, struct folio *src,
1118                                 enum migrate_mode mode)
1119 {
1120         int rc;
1121
1122         rc = migrate_huge_page_move_mapping(mapping, dst, src);
1123         if (rc != MIGRATEPAGE_SUCCESS)
1124                 return rc;
1125
1126         if (hugetlb_folio_subpool(src)) {
1127                 hugetlb_set_folio_subpool(dst,
1128                                         hugetlb_folio_subpool(src));
1129                 hugetlb_set_folio_subpool(src, NULL);
1130         }
1131
1132         if (mode != MIGRATE_SYNC_NO_COPY)
1133                 folio_migrate_copy(dst, src);
1134         else
1135                 folio_migrate_flags(dst, src);
1136
1137         return MIGRATEPAGE_SUCCESS;
1138 }
1139 #else
1140 #define hugetlbfs_migrate_folio NULL
1141 #endif
1142
1143 static int hugetlbfs_error_remove_folio(struct address_space *mapping,
1144                                 struct folio *folio)
1145 {
1146         return 0;
1147 }
1148
1149 /*
1150  * Display the mount options in /proc/mounts.
1151  */
1152 static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root)
1153 {
1154         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(root->d_sb);
1155         struct hugepage_subpool *spool = sbinfo->spool;
1156         unsigned long hpage_size = huge_page_size(sbinfo->hstate);
1157         unsigned hpage_shift = huge_page_shift(sbinfo->hstate);
1158         char mod;
1159
1160         if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
1161                 seq_printf(m, ",uid=%u",
1162                            from_kuid_munged(&init_user_ns, sbinfo->uid));
1163         if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
1164                 seq_printf(m, ",gid=%u",
1165                            from_kgid_munged(&init_user_ns, sbinfo->gid));
1166         if (sbinfo->mode != 0755)
1167                 seq_printf(m, ",mode=%o", sbinfo->mode);
1168         if (sbinfo->max_inodes != -1)
1169                 seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes);
1170
1171         hpage_size /= 1024;
1172         mod = 'K';
1173         if (hpage_size >= 1024) {
1174                 hpage_size /= 1024;
1175                 mod = 'M';
1176         }
1177         seq_printf(m, ",pagesize=%lu%c", hpage_size, mod);
1178         if (spool) {
1179                 if (spool->max_hpages != -1)
1180                         seq_printf(m, ",size=%llu",
1181                                    (unsigned long long)spool->max_hpages << hpage_shift);
1182                 if (spool->min_hpages != -1)
1183                         seq_printf(m, ",min_size=%llu",
1184                                    (unsigned long long)spool->min_hpages << hpage_shift);
1185         }
1186         return 0;
1187 }
1188
1189 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1190 {
1191         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
1192         struct hstate *h = hstate_inode(d_inode(dentry));
1193         u64 id = huge_encode_dev(dentry->d_sb->s_dev);
1194
1195         buf->f_fsid = u64_to_fsid(id);
1196         buf->f_type = HUGETLBFS_MAGIC;
1197         buf->f_bsize = huge_page_size(h);
1198         if (sbinfo) {
1199                 spin_lock(&sbinfo->stat_lock);
1200                 /* If no limits set, just report 0 or -1 for max/free/used
1201                  * blocks, like simple_statfs() */
1202                 if (sbinfo->spool) {
1203                         long free_pages;
1204
1205                         spin_lock_irq(&sbinfo->spool->lock);
1206                         buf->f_blocks = sbinfo->spool->max_hpages;
1207                         free_pages = sbinfo->spool->max_hpages
1208                                 - sbinfo->spool->used_hpages;
1209                         buf->f_bavail = buf->f_bfree = free_pages;
1210                         spin_unlock_irq(&sbinfo->spool->lock);
1211                         buf->f_files = sbinfo->max_inodes;
1212                         buf->f_ffree = sbinfo->free_inodes;
1213                 }
1214                 spin_unlock(&sbinfo->stat_lock);
1215         }
1216         buf->f_namelen = NAME_MAX;
1217         return 0;
1218 }
1219
1220 static void hugetlbfs_put_super(struct super_block *sb)
1221 {
1222         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
1223
1224         if (sbi) {
1225                 sb->s_fs_info = NULL;
1226
1227                 if (sbi->spool)
1228                         hugepage_put_subpool(sbi->spool);
1229
1230                 kfree(sbi);
1231         }
1232 }
1233
1234 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1235 {
1236         if (sbinfo->free_inodes >= 0) {
1237                 spin_lock(&sbinfo->stat_lock);
1238                 if (unlikely(!sbinfo->free_inodes)) {
1239                         spin_unlock(&sbinfo->stat_lock);
1240                         return 0;
1241                 }
1242                 sbinfo->free_inodes--;
1243                 spin_unlock(&sbinfo->stat_lock);
1244         }
1245
1246         return 1;
1247 }
1248
1249 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
1250 {
1251         if (sbinfo->free_inodes >= 0) {
1252                 spin_lock(&sbinfo->stat_lock);
1253                 sbinfo->free_inodes++;
1254                 spin_unlock(&sbinfo->stat_lock);
1255         }
1256 }
1257
1258
1259 static struct kmem_cache *hugetlbfs_inode_cachep;
1260
1261 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
1262 {
1263         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
1264         struct hugetlbfs_inode_info *p;
1265
1266         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
1267                 return NULL;
1268         p = alloc_inode_sb(sb, hugetlbfs_inode_cachep, GFP_KERNEL);
1269         if (unlikely(!p)) {
1270                 hugetlbfs_inc_free_inodes(sbinfo);
1271                 return NULL;
1272         }
1273         return &p->vfs_inode;
1274 }
1275
1276 static void hugetlbfs_free_inode(struct inode *inode)
1277 {
1278         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
1279 }
1280
1281 static void hugetlbfs_destroy_inode(struct inode *inode)
1282 {
1283         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
1284 }
1285
1286 static const struct address_space_operations hugetlbfs_aops = {
1287         .write_begin    = hugetlbfs_write_begin,
1288         .write_end      = hugetlbfs_write_end,
1289         .dirty_folio    = noop_dirty_folio,
1290         .migrate_folio  = hugetlbfs_migrate_folio,
1291         .error_remove_folio     = hugetlbfs_error_remove_folio,
1292 };
1293
1294
1295 static void init_once(void *foo)
1296 {
1297         struct hugetlbfs_inode_info *ei = foo;
1298
1299         inode_init_once(&ei->vfs_inode);
1300 }
1301
1302 const struct file_operations hugetlbfs_file_operations = {
1303         .read_iter              = hugetlbfs_read_iter,
1304         .mmap                   = hugetlbfs_file_mmap,
1305         .fsync                  = noop_fsync,
1306         .get_unmapped_area      = hugetlb_get_unmapped_area,
1307         .llseek                 = default_llseek,
1308         .fallocate              = hugetlbfs_fallocate,
1309 };
1310
1311 static const struct inode_operations hugetlbfs_dir_inode_operations = {
1312         .create         = hugetlbfs_create,
1313         .lookup         = simple_lookup,
1314         .link           = simple_link,
1315         .unlink         = simple_unlink,
1316         .symlink        = hugetlbfs_symlink,
1317         .mkdir          = hugetlbfs_mkdir,
1318         .rmdir          = simple_rmdir,
1319         .mknod          = hugetlbfs_mknod,
1320         .rename         = simple_rename,
1321         .setattr        = hugetlbfs_setattr,
1322         .tmpfile        = hugetlbfs_tmpfile,
1323 };
1324
1325 static const struct inode_operations hugetlbfs_inode_operations = {
1326         .setattr        = hugetlbfs_setattr,
1327 };
1328
1329 static const struct super_operations hugetlbfs_ops = {
1330         .alloc_inode    = hugetlbfs_alloc_inode,
1331         .free_inode     = hugetlbfs_free_inode,
1332         .destroy_inode  = hugetlbfs_destroy_inode,
1333         .evict_inode    = hugetlbfs_evict_inode,
1334         .statfs         = hugetlbfs_statfs,
1335         .put_super      = hugetlbfs_put_super,
1336         .show_options   = hugetlbfs_show_options,
1337 };
1338
1339 /*
1340  * Convert size option passed from command line to number of huge pages
1341  * in the pool specified by hstate.  Size option could be in bytes
1342  * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
1343  */
1344 static long
1345 hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
1346                          enum hugetlbfs_size_type val_type)
1347 {
1348         if (val_type == NO_SIZE)
1349                 return -1;
1350
1351         if (val_type == SIZE_PERCENT) {
1352                 size_opt <<= huge_page_shift(h);
1353                 size_opt *= h->max_huge_pages;
1354                 do_div(size_opt, 100);
1355         }
1356
1357         size_opt >>= huge_page_shift(h);
1358         return size_opt;
1359 }
1360
1361 /*
1362  * Parse one mount parameter.
1363  */
1364 static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
1365 {
1366         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1367         struct fs_parse_result result;
1368         struct hstate *h;
1369         char *rest;
1370         unsigned long ps;
1371         int opt;
1372
1373         opt = fs_parse(fc, hugetlb_fs_parameters, param, &result);
1374         if (opt < 0)
1375                 return opt;
1376
1377         switch (opt) {
1378         case Opt_uid:
1379                 ctx->uid = make_kuid(current_user_ns(), result.uint_32);
1380                 if (!uid_valid(ctx->uid))
1381                         goto bad_val;
1382                 return 0;
1383
1384         case Opt_gid:
1385                 ctx->gid = make_kgid(current_user_ns(), result.uint_32);
1386                 if (!gid_valid(ctx->gid))
1387                         goto bad_val;
1388                 return 0;
1389
1390         case Opt_mode:
1391                 ctx->mode = result.uint_32 & 01777U;
1392                 return 0;
1393
1394         case Opt_size:
1395                 /* memparse() will accept a K/M/G without a digit */
1396                 if (!param->string || !isdigit(param->string[0]))
1397                         goto bad_val;
1398                 ctx->max_size_opt = memparse(param->string, &rest);
1399                 ctx->max_val_type = SIZE_STD;
1400                 if (*rest == '%')
1401                         ctx->max_val_type = SIZE_PERCENT;
1402                 return 0;
1403
1404         case Opt_nr_inodes:
1405                 /* memparse() will accept a K/M/G without a digit */
1406                 if (!param->string || !isdigit(param->string[0]))
1407                         goto bad_val;
1408                 ctx->nr_inodes = memparse(param->string, &rest);
1409                 return 0;
1410
1411         case Opt_pagesize:
1412                 ps = memparse(param->string, &rest);
1413                 h = size_to_hstate(ps);
1414                 if (!h) {
1415                         pr_err("Unsupported page size %lu MB\n", ps / SZ_1M);
1416                         return -EINVAL;
1417                 }
1418                 ctx->hstate = h;
1419                 return 0;
1420
1421         case Opt_min_size:
1422                 /* memparse() will accept a K/M/G without a digit */
1423                 if (!param->string || !isdigit(param->string[0]))
1424                         goto bad_val;
1425                 ctx->min_size_opt = memparse(param->string, &rest);
1426                 ctx->min_val_type = SIZE_STD;
1427                 if (*rest == '%')
1428                         ctx->min_val_type = SIZE_PERCENT;
1429                 return 0;
1430
1431         default:
1432                 return -EINVAL;
1433         }
1434
1435 bad_val:
1436         return invalfc(fc, "Bad value '%s' for mount option '%s'\n",
1437                       param->string, param->key);
1438 }
1439
1440 /*
1441  * Validate the parsed options.
1442  */
1443 static int hugetlbfs_validate(struct fs_context *fc)
1444 {
1445         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1446
1447         /*
1448          * Use huge page pool size (in hstate) to convert the size
1449          * options to number of huge pages.  If NO_SIZE, -1 is returned.
1450          */
1451         ctx->max_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1452                                                    ctx->max_size_opt,
1453                                                    ctx->max_val_type);
1454         ctx->min_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
1455                                                    ctx->min_size_opt,
1456                                                    ctx->min_val_type);
1457
1458         /*
1459          * If max_size was specified, then min_size must be smaller
1460          */
1461         if (ctx->max_val_type > NO_SIZE &&
1462             ctx->min_hpages > ctx->max_hpages) {
1463                 pr_err("Minimum size can not be greater than maximum size\n");
1464                 return -EINVAL;
1465         }
1466
1467         return 0;
1468 }
1469
1470 static int
1471 hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc)
1472 {
1473         struct hugetlbfs_fs_context *ctx = fc->fs_private;
1474         struct hugetlbfs_sb_info *sbinfo;
1475
1476         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
1477         if (!sbinfo)
1478                 return -ENOMEM;
1479         sb->s_fs_info = sbinfo;
1480         spin_lock_init(&sbinfo->stat_lock);
1481         sbinfo->hstate          = ctx->hstate;
1482         sbinfo->max_inodes      = ctx->nr_inodes;
1483         sbinfo->free_inodes     = ctx->nr_inodes;
1484         sbinfo->spool           = NULL;
1485         sbinfo->uid             = ctx->uid;
1486         sbinfo->gid             = ctx->gid;
1487         sbinfo->mode            = ctx->mode;
1488
1489         /*
1490          * Allocate and initialize subpool if maximum or minimum size is
1491          * specified.  Any needed reservations (for minimum size) are taken
1492          * when the subpool is created.
1493          */
1494         if (ctx->max_hpages != -1 || ctx->min_hpages != -1) {
1495                 sbinfo->spool = hugepage_new_subpool(ctx->hstate,
1496                                                      ctx->max_hpages,
1497                                                      ctx->min_hpages);
1498                 if (!sbinfo->spool)
1499                         goto out_free;
1500         }
1501         sb->s_maxbytes = MAX_LFS_FILESIZE;
1502         sb->s_blocksize = huge_page_size(ctx->hstate);
1503         sb->s_blocksize_bits = huge_page_shift(ctx->hstate);
1504         sb->s_magic = HUGETLBFS_MAGIC;
1505         sb->s_op = &hugetlbfs_ops;
1506         sb->s_time_gran = 1;
1507
1508         /*
1509          * Due to the special and limited functionality of hugetlbfs, it does
1510          * not work well as a stacking filesystem.
1511          */
1512         sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
1513         sb->s_root = d_make_root(hugetlbfs_get_root(sb, ctx));
1514         if (!sb->s_root)
1515                 goto out_free;
1516         return 0;
1517 out_free:
1518         kfree(sbinfo->spool);
1519         kfree(sbinfo);
1520         return -ENOMEM;
1521 }
1522
1523 static int hugetlbfs_get_tree(struct fs_context *fc)
1524 {
1525         int err = hugetlbfs_validate(fc);
1526         if (err)
1527                 return err;
1528         return get_tree_nodev(fc, hugetlbfs_fill_super);
1529 }
1530
1531 static void hugetlbfs_fs_context_free(struct fs_context *fc)
1532 {
1533         kfree(fc->fs_private);
1534 }
1535
1536 static const struct fs_context_operations hugetlbfs_fs_context_ops = {
1537         .free           = hugetlbfs_fs_context_free,
1538         .parse_param    = hugetlbfs_parse_param,
1539         .get_tree       = hugetlbfs_get_tree,
1540 };
1541
1542 static int hugetlbfs_init_fs_context(struct fs_context *fc)
1543 {
1544         struct hugetlbfs_fs_context *ctx;
1545
1546         ctx = kzalloc(sizeof(struct hugetlbfs_fs_context), GFP_KERNEL);
1547         if (!ctx)
1548                 return -ENOMEM;
1549
1550         ctx->max_hpages = -1; /* No limit on size by default */
1551         ctx->nr_inodes  = -1; /* No limit on number of inodes by default */
1552         ctx->uid        = current_fsuid();
1553         ctx->gid        = current_fsgid();
1554         ctx->mode       = 0755;
1555         ctx->hstate     = &default_hstate;
1556         ctx->min_hpages = -1; /* No default minimum size */
1557         ctx->max_val_type = NO_SIZE;
1558         ctx->min_val_type = NO_SIZE;
1559         fc->fs_private = ctx;
1560         fc->ops = &hugetlbfs_fs_context_ops;
1561         return 0;
1562 }
1563
1564 static struct file_system_type hugetlbfs_fs_type = {
1565         .name                   = "hugetlbfs",
1566         .init_fs_context        = hugetlbfs_init_fs_context,
1567         .parameters             = hugetlb_fs_parameters,
1568         .kill_sb                = kill_litter_super,
1569 };
1570
1571 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
1572
1573 static int can_do_hugetlb_shm(void)
1574 {
1575         kgid_t shm_group;
1576         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
1577         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
1578 }
1579
1580 static int get_hstate_idx(int page_size_log)
1581 {
1582         struct hstate *h = hstate_sizelog(page_size_log);
1583
1584         if (!h)
1585                 return -1;
1586         return hstate_index(h);
1587 }
1588
1589 /*
1590  * Note that size should be aligned to proper hugepage size in caller side,
1591  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
1592  */
1593 struct file *hugetlb_file_setup(const char *name, size_t size,
1594                                 vm_flags_t acctflag, int creat_flags,
1595                                 int page_size_log)
1596 {
1597         struct inode *inode;
1598         struct vfsmount *mnt;
1599         int hstate_idx;
1600         struct file *file;
1601
1602         hstate_idx = get_hstate_idx(page_size_log);
1603         if (hstate_idx < 0)
1604                 return ERR_PTR(-ENODEV);
1605
1606         mnt = hugetlbfs_vfsmount[hstate_idx];
1607         if (!mnt)
1608                 return ERR_PTR(-ENOENT);
1609
1610         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
1611                 struct ucounts *ucounts = current_ucounts();
1612
1613                 if (user_shm_lock(size, ucounts)) {
1614                         pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is obsolete\n",
1615                                 current->comm, current->pid);
1616                         user_shm_unlock(size, ucounts);
1617                 }
1618                 return ERR_PTR(-EPERM);
1619         }
1620
1621         file = ERR_PTR(-ENOSPC);
1622         inode = hugetlbfs_get_inode(mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0);
1623         if (!inode)
1624                 goto out;
1625         if (creat_flags == HUGETLB_SHMFS_INODE)
1626                 inode->i_flags |= S_PRIVATE;
1627
1628         inode->i_size = size;
1629         clear_nlink(inode);
1630
1631         if (!hugetlb_reserve_pages(inode, 0,
1632                         size >> huge_page_shift(hstate_inode(inode)), NULL,
1633                         acctflag))
1634                 file = ERR_PTR(-ENOMEM);
1635         else
1636                 file = alloc_file_pseudo(inode, mnt, name, O_RDWR,
1637                                         &hugetlbfs_file_operations);
1638         if (!IS_ERR(file))
1639                 return file;
1640
1641         iput(inode);
1642 out:
1643         return file;
1644 }
1645
1646 static struct vfsmount *__init mount_one_hugetlbfs(struct hstate *h)
1647 {
1648         struct fs_context *fc;
1649         struct vfsmount *mnt;
1650
1651         fc = fs_context_for_mount(&hugetlbfs_fs_type, SB_KERNMOUNT);
1652         if (IS_ERR(fc)) {
1653                 mnt = ERR_CAST(fc);
1654         } else {
1655                 struct hugetlbfs_fs_context *ctx = fc->fs_private;
1656                 ctx->hstate = h;
1657                 mnt = fc_mount(fc);
1658                 put_fs_context(fc);
1659         }
1660         if (IS_ERR(mnt))
1661                 pr_err("Cannot mount internal hugetlbfs for page size %luK",
1662                        huge_page_size(h) / SZ_1K);
1663         return mnt;
1664 }
1665
1666 static int __init init_hugetlbfs_fs(void)
1667 {
1668         struct vfsmount *mnt;
1669         struct hstate *h;
1670         int error;
1671         int i;
1672
1673         if (!hugepages_supported()) {
1674                 pr_info("disabling because there are no supported hugepage sizes\n");
1675                 return -ENOTSUPP;
1676         }
1677
1678         error = -ENOMEM;
1679         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1680                                         sizeof(struct hugetlbfs_inode_info),
1681                                         0, SLAB_ACCOUNT, init_once);
1682         if (hugetlbfs_inode_cachep == NULL)
1683                 goto out;
1684
1685         error = register_filesystem(&hugetlbfs_fs_type);
1686         if (error)
1687                 goto out_free;
1688
1689         /* default hstate mount is required */
1690         mnt = mount_one_hugetlbfs(&default_hstate);
1691         if (IS_ERR(mnt)) {
1692                 error = PTR_ERR(mnt);
1693                 goto out_unreg;
1694         }
1695         hugetlbfs_vfsmount[default_hstate_idx] = mnt;
1696
1697         /* other hstates are optional */
1698         i = 0;
1699         for_each_hstate(h) {
1700                 if (i == default_hstate_idx) {
1701                         i++;
1702                         continue;
1703                 }
1704
1705                 mnt = mount_one_hugetlbfs(h);
1706                 if (IS_ERR(mnt))
1707                         hugetlbfs_vfsmount[i] = NULL;
1708                 else
1709                         hugetlbfs_vfsmount[i] = mnt;
1710                 i++;
1711         }
1712
1713         return 0;
1714
1715  out_unreg:
1716         (void)unregister_filesystem(&hugetlbfs_fs_type);
1717  out_free:
1718         kmem_cache_destroy(hugetlbfs_inode_cachep);
1719  out:
1720         return error;
1721 }
1722 fs_initcall(init_hugetlbfs_fs)