fs/hugetlbfs/inode.c

   1 /*
   2  * hugetlbpage-backed filesystem.  Based on ramfs.
   3  *
   4  * William Irwin, 2002
   5  *
   6  * Copyright (C) 2002 Linus Torvalds.
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/thread_info.h>
  11 #include <asm/current.h>
  12 #include <linux/sched.h>                /* remove ASAP */
  13 #include <linux/fs.h>
  14 #include <linux/mount.h>
  15 #include <linux/file.h>
  16 #include <linux/kernel.h>
  17 #include <linux/writeback.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/highmem.h>
  20 #include <linux/init.h>
  21 #include <linux/string.h>
  22 #include <linux/capability.h>
  23 #include <linux/ctype.h>
  24 #include <linux/backing-dev.h>
  25 #include <linux/hugetlb.h>
  26 #include <linux/pagevec.h>
  27 #include <linux/parser.h>
  28 #include <linux/mman.h>
  29 #include <linux/slab.h>
  30 #include <linux/dnotify.h>
  31 #include <linux/statfs.h>
  32 #include <linux/security.h>
  33 #include <linux/magic.h>
  34 #include <linux/migrate.h>
  35
  36 #include <asm/uaccess.h>
  37
  38 static const struct super_operations hugetlbfs_ops;
  39 static const struct address_space_operations hugetlbfs_aops;
  40 const struct file_operations hugetlbfs_file_operations;
  41 static const struct inode_operations hugetlbfs_dir_inode_operations;
  42 static const struct inode_operations hugetlbfs_inode_operations;
  43
  44 static struct backing_dev_info hugetlbfs_backing_dev_info = {
  45         .name           = "hugetlbfs",
  46         .ra_pages       = 0,    /* No readahead */
  47         .capabilities   = BDI_CAP_NO_ACCT_AND_WRITEBACK,
  48 };
  49
  50 int sysctl_hugetlb_shm_group;
  51
  52 enum {
  53         Opt_size, Opt_nr_inodes,
  54         Opt_mode, Opt_uid, Opt_gid,
  55         Opt_pagesize,
  56         Opt_err,
  57 };
  58
  59 static const match_table_t tokens = {
  60         {Opt_size,      "size=%s"},
  61         {Opt_nr_inodes, "nr_inodes=%s"},
  62         {Opt_mode,      "mode=%o"},
  63         {Opt_uid,       "uid=%u"},
  64         {Opt_gid,       "gid=%u"},
  65         {Opt_pagesize,  "pagesize=%s"},
  66         {Opt_err,       NULL},
  67 };
  68
  69 static void huge_pagevec_release(struct pagevec *pvec)
  70 {
  71         int i;
  72
  73         for (i = 0; i < pagevec_count(pvec); ++i)
  74                 put_page(pvec->pages[i]);
  75
  76         pagevec_reinit(pvec);
  77 }
  78
  79 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
  80 {
  81         struct inode *inode = file->f_path.dentry->d_inode;
  82         loff_t len, vma_len;
  83         int ret;
  84         struct hstate *h = hstate_file(file);
  85
  86         /*
  87          * vma address alignment (but not the pgoff alignment) has
  88          * already been checked by prepare_hugepage_range.  If you add
  89          * any error returns here, do so after setting VM_HUGETLB, so
  90          * is_vm_hugetlb_page tests below unmap_region go the right
  91          * way when do_mmap_pgoff unwinds (may be important on powerpc
  92          * and ia64).
  93          */
  94         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
  95         vma->vm_ops = &hugetlb_vm_ops;
  96
  97         if (vma->vm_pgoff & ~(huge_page_mask(h) >> PAGE_SHIFT))
  98                 return -EINVAL;
  99
 100         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
 101
 102         mutex_lock(&inode->i_mutex);
 103         file_accessed(file);
 104
 105         ret = -ENOMEM;
 106         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 107
 108         if (hugetlb_reserve_pages(inode,
 109                                 vma->vm_pgoff >> huge_page_order(h),
 110                                 len >> huge_page_shift(h), vma,
 111                                 vma->vm_flags))
 112                 goto out;
 113
 114         ret = 0;
 115         hugetlb_prefault_arch_hook(vma->vm_mm);
 116         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
 117                 inode->i_size = len;
 118 out:
 119         mutex_unlock(&inode->i_mutex);
 120
 121         return ret;
 122 }
 123
 124 /*
 125  * Called under down_write(mmap_sem).
 126  */
 127
 128 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 129 static unsigned long
 130 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 131                 unsigned long len, unsigned long pgoff, unsigned long flags)
 132 {
 133         struct mm_struct *mm = current->mm;
 134         struct vm_area_struct *vma;
 135         unsigned long start_addr;
 136         struct hstate *h = hstate_file(file);
 137
 138         if (len & ~huge_page_mask(h))
 139                 return -EINVAL;
 140         if (len > TASK_SIZE)
 141                 return -ENOMEM;
 142
 143         if (flags & MAP_FIXED) {
 144                 if (prepare_hugepage_range(file, addr, len))
 145                         return -EINVAL;
 146                 return addr;
 147         }
 148
 149         if (addr) {
 150                 addr = ALIGN(addr, huge_page_size(h));
 151                 vma = find_vma(mm, addr);
 152                 if (TASK_SIZE - len >= addr &&
 153                     (!vma || addr + len <= vma->vm_start))
 154                         return addr;
 155         }
 156
 157         start_addr = mm->free_area_cache;
 158
 159         if (len <= mm->cached_hole_size)
 160                 start_addr = TASK_UNMAPPED_BASE;
 161
 162 full_search:
 163         addr = ALIGN(start_addr, huge_page_size(h));
 164
 165         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 166                 /* At this point:  (!vma || addr < vma->vm_end). */
 167                 if (TASK_SIZE - len < addr) {
 168                         /*
 169                          * Start a new search - just in case we missed
 170                          * some holes.
 171                          */
 172                         if (start_addr != TASK_UNMAPPED_BASE) {
 173                                 start_addr = TASK_UNMAPPED_BASE;
 174                                 goto full_search;
 175                         }
 176                         return -ENOMEM;
 177                 }
 178
 179                 if (!vma || addr + len <= vma->vm_start)
 180                         return addr;
 181                 addr = ALIGN(vma->vm_end, huge_page_size(h));
 182         }
 183 }
 184 #endif
 185
 186 static int
 187 hugetlbfs_read_actor(struct page *page, unsigned long offset,
 188                         char __user *buf, unsigned long count,
 189                         unsigned long size)
 190 {
 191         char *kaddr;
 192         unsigned long left, copied = 0;
 193         int i, chunksize;
 194
 195         if (size > count)
 196                 size = count;
 197
 198         /* Find which 4k chunk and offset with in that chunk */
 199         i = offset >> PAGE_CACHE_SHIFT;
 200         offset = offset & ~PAGE_CACHE_MASK;
 201
 202         while (size) {
 203                 chunksize = PAGE_CACHE_SIZE;
 204                 if (offset)
 205                         chunksize -= offset;
 206                 if (chunksize > size)
 207                         chunksize = size;
 208                 kaddr = kmap(&page[i]);
 209                 left = __copy_to_user(buf, kaddr + offset, chunksize);
 210                 kunmap(&page[i]);
 211                 if (left) {
 212                         copied += (chunksize - left);
 213                         break;
 214                 }
 215                 offset = 0;
 216                 size -= chunksize;
 217                 buf += chunksize;
 218                 copied += chunksize;
 219                 i++;
 220         }
 221         return copied ? copied : -EFAULT;
 222 }
 223
 224 /*
 225  * Support for read() - Find the page attached to f_mapping and copy out the
 226  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
 227  * since it has PAGE_CACHE_SIZE assumptions.
 228  */
 229 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
 230                               size_t len, loff_t *ppos)
 231 {
 232         struct hstate *h = hstate_file(filp);
 233         struct address_space *mapping = filp->f_mapping;
 234         struct inode *inode = mapping->host;
 235         unsigned long index = *ppos >> huge_page_shift(h);
 236         unsigned long offset = *ppos & ~huge_page_mask(h);
 237         unsigned long end_index;
 238         loff_t isize;
 239         ssize_t retval = 0;
 240
 241         mutex_lock(&inode->i_mutex);
 242
 243         /* validate length */
 244         if (len == 0)
 245                 goto out;
 246
 247         isize = i_size_read(inode);
 248         if (!isize)
 249                 goto out;
 250
 251         end_index = (isize - 1) >> huge_page_shift(h);
 252         for (;;) {
 253                 struct page *page;
 254                 unsigned long nr, ret;
 255                 int ra;
 256
 257                 /* nr is the maximum number of bytes to copy from this page */
 258                 nr = huge_page_size(h);
 259                 if (index >= end_index) {
 260                         if (index > end_index)
 261                                 goto out;
 262                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
 263                         if (nr <= offset) {
 264                                 goto out;
 265                         }
 266                 }
 267                 nr = nr - offset;
 268
 269                 /* Find the page */
 270                 page = find_get_page(mapping, index);
 271                 if (unlikely(page == NULL)) {
 272                         /*
 273                          * We have a HOLE, zero out the user-buffer for the
 274                          * length of the hole or request.
 275                          */
 276                         ret = len < nr ? len : nr;
 277                         if (clear_user(buf, ret))
 278                                 ra = -EFAULT;
 279                         else
 280                                 ra = 0;
 281                 } else {
 282                         /*
 283                          * We have the page, copy it to user space buffer.
 284                          */
 285                         ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
 286                         ret = ra;
 287                 }
 288                 if (ra < 0) {
 289                         if (retval == 0)
 290                                 retval = ra;
 291                         if (page)
 292                                 page_cache_release(page);
 293                         goto out;
 294                 }
 295
 296                 offset += ret;
 297                 retval += ret;
 298                 len -= ret;
 299                 index += offset >> huge_page_shift(h);
 300                 offset &= ~huge_page_mask(h);
 301
 302                 if (page)
 303                         page_cache_release(page);
 304
 305                 /* short read or no more work */
 306                 if ((ret != nr) || (len == 0))
 307                         break;
 308         }
 309 out:
 310         *ppos = ((loff_t)index << huge_page_shift(h)) + offset;
 311         mutex_unlock(&inode->i_mutex);
 312         return retval;
 313 }
 314
 315 static int hugetlbfs_write_begin(struct file *file,
 316                         struct address_space *mapping,
 317                         loff_t pos, unsigned len, unsigned flags,
 318                         struct page **pagep, void **fsdata)
 319 {
 320         return -EINVAL;
 321 }
 322
 323 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
 324                         loff_t pos, unsigned len, unsigned copied,
 325                         struct page *page, void *fsdata)
 326 {
 327         BUG();
 328         return -EINVAL;
 329 }
 330
 331 static void truncate_huge_page(struct page *page)
 332 {
 333         cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
 334         ClearPageUptodate(page);
 335         remove_from_page_cache(page);
 336         put_page(page);
 337 }
 338
 339 static void truncate_hugepages(struct inode *inode, loff_t lstart)
 340 {
 341         struct hstate *h = hstate_inode(inode);
 342         struct address_space *mapping = &inode->i_data;
 343         const pgoff_t start = lstart >> huge_page_shift(h);
 344         struct pagevec pvec;
 345         pgoff_t next;
 346         int i, freed = 0;
 347
 348         pagevec_init(&pvec, 0);
 349         next = start;
 350         while (1) {
 351                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
 352                         if (next == start)
 353                                 break;
 354                         next = start;
 355                         continue;
 356                 }
 357
 358                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 359                         struct page *page = pvec.pages[i];
 360
 361                         lock_page(page);
 362                         if (page->index > next)
 363                                 next = page->index;
 364                         ++next;
 365                         truncate_huge_page(page);
 366                         unlock_page(page);
 367                         freed++;
 368                 }
 369                 huge_pagevec_release(&pvec);
 370         }
 371         BUG_ON(!lstart && mapping->nrpages);
 372         hugetlb_unreserve_pages(inode, start, freed);
 373 }
 374
 375 static void hugetlbfs_evict_inode(struct inode *inode)
 376 {
 377         truncate_hugepages(inode, 0);
 378         end_writeback(inode);
 379 }
 380
 381 static inline void
 382 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
 383 {
 384         struct vm_area_struct *vma;
 385         struct prio_tree_iter iter;
 386
 387         vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
 388                 unsigned long v_offset;
 389
 390                 /*
 391                  * Can the expression below overflow on 32-bit arches?
 392                  * No, because the prio_tree returns us only those vmas
 393                  * which overlap the truncated area starting at pgoff,
 394                  * and no vma on a 32-bit arch can span beyond the 4GB.
 395                  */
 396                 if (vma->vm_pgoff < pgoff)
 397                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
 398                 else
 399                         v_offset = 0;
 400
 401                 __unmap_hugepage_range(vma,
 402                                 vma->vm_start + v_offset, vma->vm_end, NULL);
 403         }
 404 }
 405
 406 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 407 {
 408         pgoff_t pgoff;
 409         struct address_space *mapping = inode->i_mapping;
 410         struct hstate *h = hstate_inode(inode);
 411
 412         BUG_ON(offset & ~huge_page_mask(h));
 413         pgoff = offset >> PAGE_SHIFT;
 414
 415         i_size_write(inode, offset);
 416         spin_lock(&mapping->i_mmap_lock);
 417         if (!prio_tree_empty(&mapping->i_mmap))
 418                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 419         spin_unlock(&mapping->i_mmap_lock);
 420         truncate_hugepages(inode, offset);
 421         return 0;
 422 }
 423
 424 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 425 {
 426         struct inode *inode = dentry->d_inode;
 427         struct hstate *h = hstate_inode(inode);
 428         int error;
 429         unsigned int ia_valid = attr->ia_valid;
 430
 431         BUG_ON(!inode);
 432
 433         error = inode_change_ok(inode, attr);
 434         if (error)
 435                 return error;
 436
 437         if (ia_valid & ATTR_SIZE) {
 438                 error = -EINVAL;
 439                 if (attr->ia_size & ~huge_page_mask(h))
 440                         return -EINVAL;
 441                 error = hugetlb_vmtruncate(inode, attr->ia_size);
 442                 if (error)
 443                         return error;
 444         }
 445
 446         setattr_copy(inode, attr);
 447         mark_inode_dirty(inode);
 448         return 0;
 449 }
 450
 451 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
 452                                         gid_t gid, int mode, dev_t dev)
 453 {
 454         struct inode *inode;
 455
 456         inode = new_inode(sb);
 457         if (inode) {
 458                 struct hugetlbfs_inode_info *info;
 459                 inode->i_ino = get_next_ino();
 460                 inode->i_mode = mode;
 461                 inode->i_uid = uid;
 462                 inode->i_gid = gid;
 463                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 464                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 465                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 466                 INIT_LIST_HEAD(&inode->i_mapping->private_list);
 467                 info = HUGETLBFS_I(inode);
 468                 /*
 469                  * The policy is initialized here even if we are creating a
 470                  * private inode because initialization simply creates an
 471                  * an empty rb tree and calls spin_lock_init(), later when we
 472                  * call mpol_free_shared_policy() it will just return because
 473                  * the rb tree will still be empty.
 474                  */
 475                 mpol_shared_policy_init(&info->policy, NULL);
 476                 switch (mode & S_IFMT) {
 477                 default:
 478                         init_special_inode(inode, mode, dev);
 479                         break;
 480                 case S_IFREG:
 481                         inode->i_op = &hugetlbfs_inode_operations;
 482                         inode->i_fop = &hugetlbfs_file_operations;
 483                         break;
 484                 case S_IFDIR:
 485                         inode->i_op = &hugetlbfs_dir_inode_operations;
 486                         inode->i_fop = &simple_dir_operations;
 487
 488                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 489                         inc_nlink(inode);
 490                         break;
 491                 case S_IFLNK:
 492                         inode->i_op = &page_symlink_inode_operations;
 493                         break;
 494                 }
 495         }
 496         return inode;
 497 }
 498
 499 /*
 500  * File creation. Allocate an inode, and we're done..
 501  */
 502 static int hugetlbfs_mknod(struct inode *dir,
 503                         struct dentry *dentry, int mode, dev_t dev)
 504 {
 505         struct inode *inode;
 506         int error = -ENOSPC;
 507         gid_t gid;
 508
 509         if (dir->i_mode & S_ISGID) {
 510                 gid = dir->i_gid;
 511                 if (S_ISDIR(mode))
 512                         mode |= S_ISGID;
 513         } else {
 514                 gid = current_fsgid();
 515         }
 516         inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(), gid, mode, dev);
 517         if (inode) {
 518                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 519                 d_instantiate(dentry, inode);
 520                 dget(dentry);   /* Extra count - pin the dentry in core */
 521                 error = 0;
 522         }
 523         return error;
 524 }
 525
 526 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 527 {
 528         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 529         if (!retval)
 530                 inc_nlink(dir);
 531         return retval;
 532 }
 533
 534 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
 535 {
 536         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 537 }
 538
 539 static int hugetlbfs_symlink(struct inode *dir,
 540                         struct dentry *dentry, const char *symname)
 541 {
 542         struct inode *inode;
 543         int error = -ENOSPC;
 544         gid_t gid;
 545
 546         if (dir->i_mode & S_ISGID)
 547                 gid = dir->i_gid;
 548         else
 549                 gid = current_fsgid();
 550
 551         inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(),
 552                                         gid, S_IFLNK|S_IRWXUGO, 0);
 553         if (inode) {
 554                 int l = strlen(symname)+1;
 555                 error = page_symlink(inode, symname, l);
 556                 if (!error) {
 557                         d_instantiate(dentry, inode);
 558                         dget(dentry);
 559                 } else
 560                         iput(inode);
 561         }
 562         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 563
 564         return error;
 565 }
 566
 567 /*
 568  * mark the head page dirty
 569  */
 570 static int hugetlbfs_set_page_dirty(struct page *page)
 571 {
 572         struct page *head = compound_head(page);
 573
 574         SetPageDirty(head);
 575         return 0;
 576 }
 577
 578 static int hugetlbfs_migrate_page(struct address_space *mapping,
 579                                 struct page *newpage, struct page *page)
 580 {
 581         int rc;
 582
 583         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
 584         if (rc)
 585                 return rc;
 586         migrate_page_copy(newpage, page);
 587
 588         return 0;
 589 }
 590
 591 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 592 {
 593         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
 594         struct hstate *h = hstate_inode(dentry->d_inode);
 595
 596         buf->f_type = HUGETLBFS_MAGIC;
 597         buf->f_bsize = huge_page_size(h);
 598         if (sbinfo) {
 599                 spin_lock(&sbinfo->stat_lock);
 600                 /* If no limits set, just report 0 for max/free/used
 601                  * blocks, like simple_statfs() */
 602                 if (sbinfo->max_blocks >= 0) {
 603                         buf->f_blocks = sbinfo->max_blocks;
 604                         buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
 605                         buf->f_files = sbinfo->max_inodes;
 606                         buf->f_ffree = sbinfo->free_inodes;
 607                 }
 608                 spin_unlock(&sbinfo->stat_lock);
 609         }
 610         buf->f_namelen = NAME_MAX;
 611         return 0;
 612 }
 613
 614 static void hugetlbfs_put_super(struct super_block *sb)
 615 {
 616         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 617
 618         if (sbi) {
 619                 sb->s_fs_info = NULL;
 620                 kfree(sbi);
 621         }
 622 }
 623
 624 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 625 {
 626         if (sbinfo->free_inodes >= 0) {
 627                 spin_lock(&sbinfo->stat_lock);
 628                 if (unlikely(!sbinfo->free_inodes)) {
 629                         spin_unlock(&sbinfo->stat_lock);
 630                         return 0;
 631                 }
 632                 sbinfo->free_inodes--;
 633                 spin_unlock(&sbinfo->stat_lock);
 634         }
 635
 636         return 1;
 637 }
 638
 639 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 640 {
 641         if (sbinfo->free_inodes >= 0) {
 642                 spin_lock(&sbinfo->stat_lock);
 643                 sbinfo->free_inodes++;
 644                 spin_unlock(&sbinfo->stat_lock);
 645         }
 646 }
 647
 648
 649 static struct kmem_cache *hugetlbfs_inode_cachep;
 650
 651 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 652 {
 653         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 654         struct hugetlbfs_inode_info *p;
 655
 656         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 657                 return NULL;
 658         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
 659         if (unlikely(!p)) {
 660                 hugetlbfs_inc_free_inodes(sbinfo);
 661                 return NULL;
 662         }
 663         return &p->vfs_inode;
 664 }
 665
 666 static void hugetlbfs_i_callback(struct rcu_head *head)
 667 {
 668         struct inode *inode = container_of(head, struct inode, i_rcu);
 669         INIT_LIST_HEAD(&inode->i_dentry);
 670         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 671 }
 672
 673 static void hugetlbfs_destroy_inode(struct inode *inode)
 674 {
 675         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 676         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 677         call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
 678 }
 679
 680 static const struct address_space_operations hugetlbfs_aops = {
 681         .write_begin    = hugetlbfs_write_begin,
 682         .write_end      = hugetlbfs_write_end,
 683         .set_page_dirty = hugetlbfs_set_page_dirty,
 684         .migratepage    = hugetlbfs_migrate_page,
 685 };
 686
 687
 688 static void init_once(void *foo)
 689 {
 690         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 691
 692         inode_init_once(&ei->vfs_inode);
 693 }
 694
 695 const struct file_operations hugetlbfs_file_operations = {
 696         .read                   = hugetlbfs_read,
 697         .mmap                   = hugetlbfs_file_mmap,
 698         .fsync                  = noop_fsync,
 699         .get_unmapped_area      = hugetlb_get_unmapped_area,
 700         .llseek         = default_llseek,
 701 };
 702
 703 static const struct inode_operations hugetlbfs_dir_inode_operations = {
 704         .create         = hugetlbfs_create,
 705         .lookup         = simple_lookup,
 706         .link           = simple_link,
 707         .unlink         = simple_unlink,
 708         .symlink        = hugetlbfs_symlink,
 709         .mkdir          = hugetlbfs_mkdir,
 710         .rmdir          = simple_rmdir,
 711         .mknod          = hugetlbfs_mknod,
 712         .rename         = simple_rename,
 713         .setattr        = hugetlbfs_setattr,
 714 };
 715
 716 static const struct inode_operations hugetlbfs_inode_operations = {
 717         .setattr        = hugetlbfs_setattr,
 718 };
 719
 720 static const struct super_operations hugetlbfs_ops = {
 721         .alloc_inode    = hugetlbfs_alloc_inode,
 722         .destroy_inode  = hugetlbfs_destroy_inode,
 723         .evict_inode    = hugetlbfs_evict_inode,
 724         .statfs         = hugetlbfs_statfs,
 725         .put_super      = hugetlbfs_put_super,
 726         .show_options   = generic_show_options,
 727 };
 728
 729 static int
 730 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 731 {
 732         char *p, *rest;
 733         substring_t args[MAX_OPT_ARGS];
 734         int option;
 735         unsigned long long size = 0;
 736         enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
 737
 738         if (!options)
 739                 return 0;
 740
 741         while ((p = strsep(&options, ",")) != NULL) {
 742                 int token;
 743                 if (!*p)
 744                         continue;
 745
 746                 token = match_token(p, tokens, args);
 747                 switch (token) {
 748                 case Opt_uid:
 749                         if (match_int(&args[0], &option))
 750                                 goto bad_val;
 751                         pconfig->uid = option;
 752                         break;
 753
 754                 case Opt_gid:
 755                         if (match_int(&args[0], &option))
 756                                 goto bad_val;
 757                         pconfig->gid = option;
 758                         break;
 759
 760                 case Opt_mode:
 761                         if (match_octal(&args[0], &option))
 762                                 goto bad_val;
 763                         pconfig->mode = option & 01777U;
 764                         break;
 765
 766                 case Opt_size: {
 767                         /* memparse() will accept a K/M/G without a digit */
 768                         if (!isdigit(*args[0].from))
 769                                 goto bad_val;
 770                         size = memparse(args[0].from, &rest);
 771                         setsize = SIZE_STD;
 772                         if (*rest == '%')
 773                                 setsize = SIZE_PERCENT;
 774                         break;
 775                 }
 776
 777                 case Opt_nr_inodes:
 778                         /* memparse() will accept a K/M/G without a digit */
 779                         if (!isdigit(*args[0].from))
 780                                 goto bad_val;
 781                         pconfig->nr_inodes = memparse(args[0].from, &rest);
 782                         break;
 783
 784                 case Opt_pagesize: {
 785                         unsigned long ps;
 786                         ps = memparse(args[0].from, &rest);
 787                         pconfig->hstate = size_to_hstate(ps);
 788                         if (!pconfig->hstate) {
 789                                 printk(KERN_ERR
 790                                 "hugetlbfs: Unsupported page size %lu MB\n",
 791                                         ps >> 20);
 792                                 return -EINVAL;
 793                         }
 794                         break;
 795                 }
 796
 797                 default:
 798                         printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
 799                                  p);
 800                         return -EINVAL;
 801                         break;
 802                 }
 803         }
 804
 805         /* Do size after hstate is set up */
 806         if (setsize > NO_SIZE) {
 807                 struct hstate *h = pconfig->hstate;
 808                 if (setsize == SIZE_PERCENT) {
 809                         size <<= huge_page_shift(h);
 810                         size *= h->max_huge_pages;
 811                         do_div(size, 100);
 812                 }
 813                 pconfig->nr_blocks = (size >> huge_page_shift(h));
 814         }
 815
 816         return 0;
 817
 818 bad_val:
 819         printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
 820                args[0].from, p);
 821         return -EINVAL;
 822 }
 823
 824 static int
 825 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 826 {
 827         struct inode * inode;
 828         struct dentry * root;
 829         int ret;
 830         struct hugetlbfs_config config;
 831         struct hugetlbfs_sb_info *sbinfo;
 832
 833         save_mount_options(sb, data);
 834
 835         config.nr_blocks = -1; /* No limit on size by default */
 836         config.nr_inodes = -1; /* No limit on number of inodes by default */
 837         config.uid = current_fsuid();
 838         config.gid = current_fsgid();
 839         config.mode = 0755;
 840         config.hstate = &default_hstate;
 841         ret = hugetlbfs_parse_options(data, &config);
 842         if (ret)
 843                 return ret;
 844
 845         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 846         if (!sbinfo)
 847                 return -ENOMEM;
 848         sb->s_fs_info = sbinfo;
 849         sbinfo->hstate = config.hstate;
 850         spin_lock_init(&sbinfo->stat_lock);
 851         sbinfo->max_blocks = config.nr_blocks;
 852         sbinfo->free_blocks = config.nr_blocks;
 853         sbinfo->max_inodes = config.nr_inodes;
 854         sbinfo->free_inodes = config.nr_inodes;
 855         sb->s_maxbytes = MAX_LFS_FILESIZE;
 856         sb->s_blocksize = huge_page_size(config.hstate);
 857         sb->s_blocksize_bits = huge_page_shift(config.hstate);
 858         sb->s_magic = HUGETLBFS_MAGIC;
 859         sb->s_op = &hugetlbfs_ops;
 860         sb->s_time_gran = 1;
 861         inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
 862                                         S_IFDIR | config.mode, 0);
 863         if (!inode)
 864                 goto out_free;
 865
 866         root = d_alloc_root(inode);
 867         if (!root) {
 868                 iput(inode);
 869                 goto out_free;
 870         }
 871         sb->s_root = root;
 872         return 0;
 873 out_free:
 874         kfree(sbinfo);
 875         return -ENOMEM;
 876 }
 877
 878 int hugetlb_get_quota(struct address_space *mapping, long delta)
 879 {
 880         int ret = 0;
 881         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 882
 883         if (sbinfo->free_blocks > -1) {
 884                 spin_lock(&sbinfo->stat_lock);
 885                 if (sbinfo->free_blocks - delta >= 0)
 886                         sbinfo->free_blocks -= delta;
 887                 else
 888                         ret = -ENOMEM;
 889                 spin_unlock(&sbinfo->stat_lock);
 890         }
 891
 892         return ret;
 893 }
 894
 895 void hugetlb_put_quota(struct address_space *mapping, long delta)
 896 {
 897         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 898
 899         if (sbinfo->free_blocks > -1) {
 900                 spin_lock(&sbinfo->stat_lock);
 901                 sbinfo->free_blocks += delta;
 902                 spin_unlock(&sbinfo->stat_lock);
 903         }
 904 }
 905
 906 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
 907         int flags, const char *dev_name, void *data)
 908 {
 909         return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
 910 }
 911
 912 static struct file_system_type hugetlbfs_fs_type = {
 913         .name           = "hugetlbfs",
 914         .mount          = hugetlbfs_mount,
 915         .kill_sb        = kill_litter_super,
 916 };
 917
 918 static struct vfsmount *hugetlbfs_vfsmount;
 919
 920 static int can_do_hugetlb_shm(void)
 921 {
 922         return capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group);
 923 }
 924
 925 struct file *hugetlb_file_setup(const char *name, size_t size, int acctflag,
 926                                 struct user_struct **user, int creat_flags)
 927 {
 928         int error = -ENOMEM;
 929         struct file *file;
 930         struct inode *inode;
 931         struct path path;
 932         struct dentry *root;
 933         struct qstr quick_string;
 934
 935         *user = NULL;
 936         if (!hugetlbfs_vfsmount)
 937                 return ERR_PTR(-ENOENT);
 938
 939         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
 940                 *user = current_user();
 941                 if (user_shm_lock(size, *user)) {
 942                         printk_once(KERN_WARNING "Using mlock ulimits for SHM_HUGETLB is deprecated\n");
 943                 } else {
 944                         *user = NULL;
 945                         return ERR_PTR(-EPERM);
 946                 }
 947         }
 948
 949         root = hugetlbfs_vfsmount->mnt_root;
 950         quick_string.name = name;
 951         quick_string.len = strlen(quick_string.name);
 952         quick_string.hash = 0;
 953         path.dentry = d_alloc(root, &quick_string);
 954         if (!path.dentry)
 955                 goto out_shm_unlock;
 956
 957         path.mnt = mntget(hugetlbfs_vfsmount);
 958         error = -ENOSPC;
 959         inode = hugetlbfs_get_inode(root->d_sb, current_fsuid(),
 960                                 current_fsgid(), S_IFREG | S_IRWXUGO, 0);
 961         if (!inode)
 962                 goto out_dentry;
 963
 964         error = -ENOMEM;
 965         if (hugetlb_reserve_pages(inode, 0,
 966                         size >> huge_page_shift(hstate_inode(inode)), NULL,
 967                         acctflag))
 968                 goto out_inode;
 969
 970         d_instantiate(path.dentry, inode);
 971         inode->i_size = size;
 972         inode->i_nlink = 0;
 973
 974         error = -ENFILE;
 975         file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
 976                         &hugetlbfs_file_operations);
 977         if (!file)
 978                 goto out_dentry; /* inode is already attached */
 979
 980         return file;
 981
 982 out_inode:
 983         iput(inode);
 984 out_dentry:
 985         path_put(&path);
 986 out_shm_unlock:
 987         if (*user) {
 988                 user_shm_unlock(size, *user);
 989                 *user = NULL;
 990         }
 991         return ERR_PTR(error);
 992 }
 993
 994 static int __init init_hugetlbfs_fs(void)
 995 {
 996         int error;
 997         struct vfsmount *vfsmount;
 998
 999         error = bdi_init(&hugetlbfs_backing_dev_info);
1000         if (error)
1001                 return error;
1002
1003         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1004                                         sizeof(struct hugetlbfs_inode_info),
1005                                         0, 0, init_once);
1006         if (hugetlbfs_inode_cachep == NULL)
1007                 goto out2;
1008
1009         error = register_filesystem(&hugetlbfs_fs_type);
1010         if (error)
1011                 goto out;
1012
1013         vfsmount = kern_mount(&hugetlbfs_fs_type);
1014
1015         if (!IS_ERR(vfsmount)) {
1016                 hugetlbfs_vfsmount = vfsmount;
1017                 return 0;
1018         }
1019
1020         error = PTR_ERR(vfsmount);
1021
1022  out:
1023         if (error)
1024                 kmem_cache_destroy(hugetlbfs_inode_cachep);
1025  out2:
1026         bdi_destroy(&hugetlbfs_backing_dev_info);
1027         return error;
1028 }
1029
1030 static void __exit exit_hugetlbfs_fs(void)
1031 {
1032         kmem_cache_destroy(hugetlbfs_inode_cachep);
1033         unregister_filesystem(&hugetlbfs_fs_type);
1034         bdi_destroy(&hugetlbfs_backing_dev_info);
1035 }
1036
1037 module_init(init_hugetlbfs_fs)
1038 module_exit(exit_hugetlbfs_fs)
1039
1040 MODULE_LICENSE("GPL");