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/quotaops.h>
  30 #include <linux/slab.h>
  31 #include <linux/dnotify.h>
  32 #include <linux/statfs.h>
  33 #include <linux/security.h>
  34
  35 #include <asm/uaccess.h>
  36
  37 /* some random number */
  38 #define HUGETLBFS_MAGIC 0x958458f6
  39
  40 static const struct super_operations hugetlbfs_ops;
  41 static const struct address_space_operations hugetlbfs_aops;
  42 const struct file_operations hugetlbfs_file_operations;
  43 static const struct inode_operations hugetlbfs_dir_inode_operations;
  44 static const struct inode_operations hugetlbfs_inode_operations;
  45
  46 static struct backing_dev_info hugetlbfs_backing_dev_info = {
  47         .ra_pages       = 0,    /* No readahead */
  48         .capabilities   = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
  49 };
  50
  51 int sysctl_hugetlb_shm_group;
  52
  53 enum {
  54         Opt_size, Opt_nr_inodes,
  55         Opt_mode, Opt_uid, Opt_gid,
  56         Opt_err,
  57 };
  58
  59 static 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_err,       NULL},
  66 };
  67
  68 static void huge_pagevec_release(struct pagevec *pvec)
  69 {
  70         int i;
  71
  72         for (i = 0; i < pagevec_count(pvec); ++i)
  73                 put_page(pvec->pages[i]);
  74
  75         pagevec_reinit(pvec);
  76 }
  77
  78 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
  79 {
  80         struct inode *inode = file->f_path.dentry->d_inode;
  81         loff_t len, vma_len;
  82         int ret;
  83
  84         /*
  85          * vma address alignment (but not the pgoff alignment) has
  86          * already been checked by prepare_hugepage_range.  If you add
  87          * any error returns here, do so after setting VM_HUGETLB, so
  88          * is_vm_hugetlb_page tests below unmap_region go the right
  89          * way when do_mmap_pgoff unwinds (may be important on powerpc
  90          * and ia64).
  91          */
  92         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
  93         vma->vm_ops = &hugetlb_vm_ops;
  94
  95         if (vma->vm_pgoff & ~(HPAGE_MASK >> PAGE_SHIFT))
  96                 return -EINVAL;
  97
  98         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
  99
 100         mutex_lock(&inode->i_mutex);
 101         file_accessed(file);
 102
 103         ret = -ENOMEM;
 104         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 105
 106         if (vma->vm_flags & VM_MAYSHARE &&
 107             hugetlb_reserve_pages(inode, vma->vm_pgoff >> (HPAGE_SHIFT-PAGE_SHIFT),
 108                                   len >> HPAGE_SHIFT))
 109                 goto out;
 110
 111         ret = 0;
 112         hugetlb_prefault_arch_hook(vma->vm_mm);
 113         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
 114                 inode->i_size = len;
 115 out:
 116         mutex_unlock(&inode->i_mutex);
 117
 118         return ret;
 119 }
 120
 121 /*
 122  * Called under down_write(mmap_sem).
 123  */
 124
 125 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 126 static unsigned long
 127 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 128                 unsigned long len, unsigned long pgoff, unsigned long flags)
 129 {
 130         struct mm_struct *mm = current->mm;
 131         struct vm_area_struct *vma;
 132         unsigned long start_addr;
 133
 134         if (len & ~HPAGE_MASK)
 135                 return -EINVAL;
 136         if (len > TASK_SIZE)
 137                 return -ENOMEM;
 138
 139         if (flags & MAP_FIXED) {
 140                 if (prepare_hugepage_range(addr, len))
 141                         return -EINVAL;
 142                 return addr;
 143         }
 144
 145         if (addr) {
 146                 addr = ALIGN(addr, HPAGE_SIZE);
 147                 vma = find_vma(mm, addr);
 148                 if (TASK_SIZE - len >= addr &&
 149                     (!vma || addr + len <= vma->vm_start))
 150                         return addr;
 151         }
 152
 153         start_addr = mm->free_area_cache;
 154
 155         if (len <= mm->cached_hole_size)
 156                 start_addr = TASK_UNMAPPED_BASE;
 157
 158 full_search:
 159         addr = ALIGN(start_addr, HPAGE_SIZE);
 160
 161         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 162                 /* At this point:  (!vma || addr < vma->vm_end). */
 163                 if (TASK_SIZE - len < addr) {
 164                         /*
 165                          * Start a new search - just in case we missed
 166                          * some holes.
 167                          */
 168                         if (start_addr != TASK_UNMAPPED_BASE) {
 169                                 start_addr = TASK_UNMAPPED_BASE;
 170                                 goto full_search;
 171                         }
 172                         return -ENOMEM;
 173                 }
 174
 175                 if (!vma || addr + len <= vma->vm_start)
 176                         return addr;
 177                 addr = ALIGN(vma->vm_end, HPAGE_SIZE);
 178         }
 179 }
 180 #endif
 181
 182 /*
 183  * Read a page. Again trivial. If it didn't already exist
 184  * in the page cache, it is zero-filled.
 185  */
 186 static int hugetlbfs_readpage(struct file *file, struct page * page)
 187 {
 188         unlock_page(page);
 189         return -EINVAL;
 190 }
 191
 192 static int hugetlbfs_write_begin(struct file *file,
 193                         struct address_space *mapping,
 194                         loff_t pos, unsigned len, unsigned flags,
 195                         struct page **pagep, void **fsdata)
 196 {
 197         return -EINVAL;
 198 }
 199
 200 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
 201                         loff_t pos, unsigned len, unsigned copied,
 202                         struct page *page, void *fsdata)
 203 {
 204         BUG();
 205         return -EINVAL;
 206 }
 207
 208 static void truncate_huge_page(struct page *page)
 209 {
 210         cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
 211         ClearPageUptodate(page);
 212         remove_from_page_cache(page);
 213         put_page(page);
 214 }
 215
 216 static void truncate_hugepages(struct inode *inode, loff_t lstart)
 217 {
 218         struct address_space *mapping = &inode->i_data;
 219         const pgoff_t start = lstart >> HPAGE_SHIFT;
 220         struct pagevec pvec;
 221         pgoff_t next;
 222         int i, freed = 0;
 223
 224         pagevec_init(&pvec, 0);
 225         next = start;
 226         while (1) {
 227                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
 228                         if (next == start)
 229                                 break;
 230                         next = start;
 231                         continue;
 232                 }
 233
 234                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 235                         struct page *page = pvec.pages[i];
 236
 237                         lock_page(page);
 238                         if (page->index > next)
 239                                 next = page->index;
 240                         ++next;
 241                         truncate_huge_page(page);
 242                         unlock_page(page);
 243                         hugetlb_put_quota(mapping);
 244                         freed++;
 245                 }
 246                 huge_pagevec_release(&pvec);
 247         }
 248         BUG_ON(!lstart && mapping->nrpages);
 249         hugetlb_unreserve_pages(inode, start, freed);
 250 }
 251
 252 static void hugetlbfs_delete_inode(struct inode *inode)
 253 {
 254         truncate_hugepages(inode, 0);
 255         clear_inode(inode);
 256 }
 257
 258 static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock)
 259 {
 260         struct super_block *sb = inode->i_sb;
 261
 262         if (!hlist_unhashed(&inode->i_hash)) {
 263                 if (!(inode->i_state & (I_DIRTY|I_LOCK)))
 264                         list_move(&inode->i_list, &inode_unused);
 265                 inodes_stat.nr_unused++;
 266                 if (!sb || (sb->s_flags & MS_ACTIVE)) {
 267                         spin_unlock(&inode_lock);
 268                         return;
 269                 }
 270                 inode->i_state |= I_WILL_FREE;
 271                 spin_unlock(&inode_lock);
 272                 /*
 273                  * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
 274                  * in our backing_dev_info.
 275                  */
 276                 write_inode_now(inode, 1);
 277                 spin_lock(&inode_lock);
 278                 inode->i_state &= ~I_WILL_FREE;
 279                 inodes_stat.nr_unused--;
 280                 hlist_del_init(&inode->i_hash);
 281         }
 282         list_del_init(&inode->i_list);
 283         list_del_init(&inode->i_sb_list);
 284         inode->i_state |= I_FREEING;
 285         inodes_stat.nr_inodes--;
 286         spin_unlock(&inode_lock);
 287         truncate_hugepages(inode, 0);
 288         clear_inode(inode);
 289         destroy_inode(inode);
 290 }
 291
 292 static void hugetlbfs_drop_inode(struct inode *inode)
 293 {
 294         if (!inode->i_nlink)
 295                 generic_delete_inode(inode);
 296         else
 297                 hugetlbfs_forget_inode(inode);
 298 }
 299
 300 static inline void
 301 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
 302 {
 303         struct vm_area_struct *vma;
 304         struct prio_tree_iter iter;
 305
 306         vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
 307                 unsigned long v_offset;
 308
 309                 /*
 310                  * Can the expression below overflow on 32-bit arches?
 311                  * No, because the prio_tree returns us only those vmas
 312                  * which overlap the truncated area starting at pgoff,
 313                  * and no vma on a 32-bit arch can span beyond the 4GB.
 314                  */
 315                 if (vma->vm_pgoff < pgoff)
 316                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
 317                 else
 318                         v_offset = 0;
 319
 320                 __unmap_hugepage_range(vma,
 321                                 vma->vm_start + v_offset, vma->vm_end);
 322         }
 323 }
 324
 325 /*
 326  * Expanding truncates are not allowed.
 327  */
 328 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 329 {
 330         pgoff_t pgoff;
 331         struct address_space *mapping = inode->i_mapping;
 332
 333         if (offset > inode->i_size)
 334                 return -EINVAL;
 335
 336         BUG_ON(offset & ~HPAGE_MASK);
 337         pgoff = offset >> PAGE_SHIFT;
 338
 339         inode->i_size = offset;
 340         spin_lock(&mapping->i_mmap_lock);
 341         if (!prio_tree_empty(&mapping->i_mmap))
 342                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 343         spin_unlock(&mapping->i_mmap_lock);
 344         truncate_hugepages(inode, offset);
 345         return 0;
 346 }
 347
 348 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 349 {
 350         struct inode *inode = dentry->d_inode;
 351         int error;
 352         unsigned int ia_valid = attr->ia_valid;
 353
 354         BUG_ON(!inode);
 355
 356         error = inode_change_ok(inode, attr);
 357         if (error)
 358                 goto out;
 359
 360         if (ia_valid & ATTR_SIZE) {
 361                 error = -EINVAL;
 362                 if (!(attr->ia_size & ~HPAGE_MASK))
 363                         error = hugetlb_vmtruncate(inode, attr->ia_size);
 364                 if (error)
 365                         goto out;
 366                 attr->ia_valid &= ~ATTR_SIZE;
 367         }
 368         error = inode_setattr(inode, attr);
 369 out:
 370         return error;
 371 }
 372
 373 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
 374                                         gid_t gid, int mode, dev_t dev)
 375 {
 376         struct inode *inode;
 377
 378         inode = new_inode(sb);
 379         if (inode) {
 380                 struct hugetlbfs_inode_info *info;
 381                 inode->i_mode = mode;
 382                 inode->i_uid = uid;
 383                 inode->i_gid = gid;
 384                 inode->i_blocks = 0;
 385                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 386                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 387                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 388                 INIT_LIST_HEAD(&inode->i_mapping->private_list);
 389                 info = HUGETLBFS_I(inode);
 390                 mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, NULL);
 391                 switch (mode & S_IFMT) {
 392                 default:
 393                         init_special_inode(inode, mode, dev);
 394                         break;
 395                 case S_IFREG:
 396                         inode->i_op = &hugetlbfs_inode_operations;
 397                         inode->i_fop = &hugetlbfs_file_operations;
 398                         break;
 399                 case S_IFDIR:
 400                         inode->i_op = &hugetlbfs_dir_inode_operations;
 401                         inode->i_fop = &simple_dir_operations;
 402
 403                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 404                         inc_nlink(inode);
 405                         break;
 406                 case S_IFLNK:
 407                         inode->i_op = &page_symlink_inode_operations;
 408                         break;
 409                 }
 410         }
 411         return inode;
 412 }
 413
 414 /*
 415  * File creation. Allocate an inode, and we're done..
 416  */
 417 static int hugetlbfs_mknod(struct inode *dir,
 418                         struct dentry *dentry, int mode, dev_t dev)
 419 {
 420         struct inode *inode;
 421         int error = -ENOSPC;
 422         gid_t gid;
 423
 424         if (dir->i_mode & S_ISGID) {
 425                 gid = dir->i_gid;
 426                 if (S_ISDIR(mode))
 427                         mode |= S_ISGID;
 428         } else {
 429                 gid = current->fsgid;
 430         }
 431         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev);
 432         if (inode) {
 433                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 434                 d_instantiate(dentry, inode);
 435                 dget(dentry);   /* Extra count - pin the dentry in core */
 436                 error = 0;
 437         }
 438         return error;
 439 }
 440
 441 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 442 {
 443         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 444         if (!retval)
 445                 inc_nlink(dir);
 446         return retval;
 447 }
 448
 449 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
 450 {
 451         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 452 }
 453
 454 static int hugetlbfs_symlink(struct inode *dir,
 455                         struct dentry *dentry, const char *symname)
 456 {
 457         struct inode *inode;
 458         int error = -ENOSPC;
 459         gid_t gid;
 460
 461         if (dir->i_mode & S_ISGID)
 462                 gid = dir->i_gid;
 463         else
 464                 gid = current->fsgid;
 465
 466         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
 467                                         gid, S_IFLNK|S_IRWXUGO, 0);
 468         if (inode) {
 469                 int l = strlen(symname)+1;
 470                 error = page_symlink(inode, symname, l);
 471                 if (!error) {
 472                         d_instantiate(dentry, inode);
 473                         dget(dentry);
 474                 } else
 475                         iput(inode);
 476         }
 477         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 478
 479         return error;
 480 }
 481
 482 /*
 483  * mark the head page dirty
 484  */
 485 static int hugetlbfs_set_page_dirty(struct page *page)
 486 {
 487         struct page *head = compound_head(page);
 488
 489         SetPageDirty(head);
 490         return 0;
 491 }
 492
 493 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 494 {
 495         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
 496
 497         buf->f_type = HUGETLBFS_MAGIC;
 498         buf->f_bsize = HPAGE_SIZE;
 499         if (sbinfo) {
 500                 spin_lock(&sbinfo->stat_lock);
 501                 /* If no limits set, just report 0 for max/free/used
 502                  * blocks, like simple_statfs() */
 503                 if (sbinfo->max_blocks >= 0) {
 504                         buf->f_blocks = sbinfo->max_blocks;
 505                         buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
 506                         buf->f_files = sbinfo->max_inodes;
 507                         buf->f_ffree = sbinfo->free_inodes;
 508                 }
 509                 spin_unlock(&sbinfo->stat_lock);
 510         }
 511         buf->f_namelen = NAME_MAX;
 512         return 0;
 513 }
 514
 515 static void hugetlbfs_put_super(struct super_block *sb)
 516 {
 517         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 518
 519         if (sbi) {
 520                 sb->s_fs_info = NULL;
 521                 kfree(sbi);
 522         }
 523 }
 524
 525 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 526 {
 527         if (sbinfo->free_inodes >= 0) {
 528                 spin_lock(&sbinfo->stat_lock);
 529                 if (unlikely(!sbinfo->free_inodes)) {
 530                         spin_unlock(&sbinfo->stat_lock);
 531                         return 0;
 532                 }
 533                 sbinfo->free_inodes--;
 534                 spin_unlock(&sbinfo->stat_lock);
 535         }
 536
 537         return 1;
 538 }
 539
 540 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 541 {
 542         if (sbinfo->free_inodes >= 0) {
 543                 spin_lock(&sbinfo->stat_lock);
 544                 sbinfo->free_inodes++;
 545                 spin_unlock(&sbinfo->stat_lock);
 546         }
 547 }
 548
 549
 550 static struct kmem_cache *hugetlbfs_inode_cachep;
 551
 552 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 553 {
 554         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 555         struct hugetlbfs_inode_info *p;
 556
 557         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 558                 return NULL;
 559         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
 560         if (unlikely(!p)) {
 561                 hugetlbfs_inc_free_inodes(sbinfo);
 562                 return NULL;
 563         }
 564         return &p->vfs_inode;
 565 }
 566
 567 static void hugetlbfs_destroy_inode(struct inode *inode)
 568 {
 569         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 570         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 571         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 572 }
 573
 574 static const struct address_space_operations hugetlbfs_aops = {
 575         .readpage       = hugetlbfs_readpage,
 576         .write_begin    = hugetlbfs_write_begin,
 577         .write_end      = hugetlbfs_write_end,
 578         .set_page_dirty = hugetlbfs_set_page_dirty,
 579 };
 580
 581
 582 static void init_once(void *foo, struct kmem_cache *cachep, unsigned long flags)
 583 {
 584         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 585
 586         inode_init_once(&ei->vfs_inode);
 587 }
 588
 589 const struct file_operations hugetlbfs_file_operations = {
 590         .mmap                   = hugetlbfs_file_mmap,
 591         .fsync                  = simple_sync_file,
 592         .get_unmapped_area      = hugetlb_get_unmapped_area,
 593 };
 594
 595 static const struct inode_operations hugetlbfs_dir_inode_operations = {
 596         .create         = hugetlbfs_create,
 597         .lookup         = simple_lookup,
 598         .link           = simple_link,
 599         .unlink         = simple_unlink,
 600         .symlink        = hugetlbfs_symlink,
 601         .mkdir          = hugetlbfs_mkdir,
 602         .rmdir          = simple_rmdir,
 603         .mknod          = hugetlbfs_mknod,
 604         .rename         = simple_rename,
 605         .setattr        = hugetlbfs_setattr,
 606 };
 607
 608 static const struct inode_operations hugetlbfs_inode_operations = {
 609         .setattr        = hugetlbfs_setattr,
 610 };
 611
 612 static const struct super_operations hugetlbfs_ops = {
 613         .alloc_inode    = hugetlbfs_alloc_inode,
 614         .destroy_inode  = hugetlbfs_destroy_inode,
 615         .statfs         = hugetlbfs_statfs,
 616         .delete_inode   = hugetlbfs_delete_inode,
 617         .drop_inode     = hugetlbfs_drop_inode,
 618         .put_super      = hugetlbfs_put_super,
 619 };
 620
 621 static int
 622 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 623 {
 624         char *p, *rest;
 625         substring_t args[MAX_OPT_ARGS];
 626         int option;
 627
 628         if (!options)
 629                 return 0;
 630
 631         while ((p = strsep(&options, ",")) != NULL) {
 632                 int token;
 633                 if (!*p)
 634                         continue;
 635
 636                 token = match_token(p, tokens, args);
 637                 switch (token) {
 638                 case Opt_uid:
 639                         if (match_int(&args[0], &option))
 640                                 goto bad_val;
 641                         pconfig->uid = option;
 642                         break;
 643
 644                 case Opt_gid:
 645                         if (match_int(&args[0], &option))
 646                                 goto bad_val;
 647                         pconfig->gid = option;
 648                         break;
 649
 650                 case Opt_mode:
 651                         if (match_octal(&args[0], &option))
 652                                 goto bad_val;
 653                         pconfig->mode = option & 0777U;
 654                         break;
 655
 656                 case Opt_size: {
 657                         unsigned long long size;
 658                         /* memparse() will accept a K/M/G without a digit */
 659                         if (!isdigit(*args[0].from))
 660                                 goto bad_val;
 661                         size = memparse(args[0].from, &rest);
 662                         if (*rest == '%') {
 663                                 size <<= HPAGE_SHIFT;
 664                                 size *= max_huge_pages;
 665                                 do_div(size, 100);
 666                         }
 667                         pconfig->nr_blocks = (size >> HPAGE_SHIFT);
 668                         break;
 669                 }
 670
 671                 case Opt_nr_inodes:
 672                         /* memparse() will accept a K/M/G without a digit */
 673                         if (!isdigit(*args[0].from))
 674                                 goto bad_val;
 675                         pconfig->nr_inodes = memparse(args[0].from, &rest);
 676                         break;
 677
 678                 default:
 679                         printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
 680                                  p);
 681                         return -EINVAL;
 682                         break;
 683                 }
 684         }
 685         return 0;
 686
 687 bad_val:
 688         printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
 689                args[0].from, p);
 690         return 1;
 691 }
 692
 693 static int
 694 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 695 {
 696         struct inode * inode;
 697         struct dentry * root;
 698         int ret;
 699         struct hugetlbfs_config config;
 700         struct hugetlbfs_sb_info *sbinfo;
 701
 702         config.nr_blocks = -1; /* No limit on size by default */
 703         config.nr_inodes = -1; /* No limit on number of inodes by default */
 704         config.uid = current->fsuid;
 705         config.gid = current->fsgid;
 706         config.mode = 0755;
 707         ret = hugetlbfs_parse_options(data, &config);
 708         if (ret)
 709                 return ret;
 710
 711         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 712         if (!sbinfo)
 713                 return -ENOMEM;
 714         sb->s_fs_info = sbinfo;
 715         spin_lock_init(&sbinfo->stat_lock);
 716         sbinfo->max_blocks = config.nr_blocks;
 717         sbinfo->free_blocks = config.nr_blocks;
 718         sbinfo->max_inodes = config.nr_inodes;
 719         sbinfo->free_inodes = config.nr_inodes;
 720         sb->s_maxbytes = MAX_LFS_FILESIZE;
 721         sb->s_blocksize = HPAGE_SIZE;
 722         sb->s_blocksize_bits = HPAGE_SHIFT;
 723         sb->s_magic = HUGETLBFS_MAGIC;
 724         sb->s_op = &hugetlbfs_ops;
 725         sb->s_time_gran = 1;
 726         inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
 727                                         S_IFDIR | config.mode, 0);
 728         if (!inode)
 729                 goto out_free;
 730
 731         root = d_alloc_root(inode);
 732         if (!root) {
 733                 iput(inode);
 734                 goto out_free;
 735         }
 736         sb->s_root = root;
 737         return 0;
 738 out_free:
 739         kfree(sbinfo);
 740         return -ENOMEM;
 741 }
 742
 743 int hugetlb_get_quota(struct address_space *mapping)
 744 {
 745         int ret = 0;
 746         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 747
 748         if (sbinfo->free_blocks > -1) {
 749                 spin_lock(&sbinfo->stat_lock);
 750                 if (sbinfo->free_blocks > 0)
 751                         sbinfo->free_blocks--;
 752                 else
 753                         ret = -ENOMEM;
 754                 spin_unlock(&sbinfo->stat_lock);
 755         }
 756
 757         return ret;
 758 }
 759
 760 void hugetlb_put_quota(struct address_space *mapping)
 761 {
 762         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 763
 764         if (sbinfo->free_blocks > -1) {
 765                 spin_lock(&sbinfo->stat_lock);
 766                 sbinfo->free_blocks++;
 767                 spin_unlock(&sbinfo->stat_lock);
 768         }
 769 }
 770
 771 static int hugetlbfs_get_sb(struct file_system_type *fs_type,
 772         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 773 {
 774         return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super, mnt);
 775 }
 776
 777 static struct file_system_type hugetlbfs_fs_type = {
 778         .name           = "hugetlbfs",
 779         .get_sb         = hugetlbfs_get_sb,
 780         .kill_sb        = kill_litter_super,
 781 };
 782
 783 static struct vfsmount *hugetlbfs_vfsmount;
 784
 785 static int can_do_hugetlb_shm(void)
 786 {
 787         return likely(capable(CAP_IPC_LOCK) ||
 788                         in_group_p(sysctl_hugetlb_shm_group) ||
 789                         can_do_mlock());
 790 }
 791
 792 struct file *hugetlb_file_setup(const char *name, size_t size)
 793 {
 794         int error = -ENOMEM;
 795         struct file *file;
 796         struct inode *inode;
 797         struct dentry *dentry, *root;
 798         struct qstr quick_string;
 799
 800         if (!hugetlbfs_vfsmount)
 801                 return ERR_PTR(-ENOENT);
 802
 803         if (!can_do_hugetlb_shm())
 804                 return ERR_PTR(-EPERM);
 805
 806         if (!user_shm_lock(size, current->user))
 807                 return ERR_PTR(-ENOMEM);
 808
 809         root = hugetlbfs_vfsmount->mnt_root;
 810         quick_string.name = name;
 811         quick_string.len = strlen(quick_string.name);
 812         quick_string.hash = 0;
 813         dentry = d_alloc(root, &quick_string);
 814         if (!dentry)
 815                 goto out_shm_unlock;
 816
 817         error = -ENFILE;
 818         file = get_empty_filp();
 819         if (!file)
 820                 goto out_dentry;
 821
 822         error = -ENOSPC;
 823         inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
 824                                 current->fsgid, S_IFREG | S_IRWXUGO, 0);
 825         if (!inode)
 826                 goto out_file;
 827
 828         error = -ENOMEM;
 829         if (hugetlb_reserve_pages(inode, 0, size >> HPAGE_SHIFT))
 830                 goto out_inode;
 831
 832         d_instantiate(dentry, inode);
 833         inode->i_size = size;
 834         inode->i_nlink = 0;
 835         file->f_path.mnt = mntget(hugetlbfs_vfsmount);
 836         file->f_path.dentry = dentry;
 837         file->f_mapping = inode->i_mapping;
 838         file->f_op = &hugetlbfs_file_operations;
 839         file->f_mode = FMODE_WRITE | FMODE_READ;
 840         return file;
 841
 842 out_inode:
 843         iput(inode);
 844 out_file:
 845         put_filp(file);
 846 out_dentry:
 847         dput(dentry);
 848 out_shm_unlock:
 849         user_shm_unlock(size, current->user);
 850         return ERR_PTR(error);
 851 }
 852
 853 static int __init init_hugetlbfs_fs(void)
 854 {
 855         int error;
 856         struct vfsmount *vfsmount;
 857
 858         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
 859                                         sizeof(struct hugetlbfs_inode_info),
 860                                         0, 0, init_once);
 861         if (hugetlbfs_inode_cachep == NULL)
 862                 return -ENOMEM;
 863
 864         error = register_filesystem(&hugetlbfs_fs_type);
 865         if (error)
 866                 goto out;
 867
 868         vfsmount = kern_mount(&hugetlbfs_fs_type);
 869
 870         if (!IS_ERR(vfsmount)) {
 871                 hugetlbfs_vfsmount = vfsmount;
 872                 return 0;
 873         }
 874
 875         error = PTR_ERR(vfsmount);
 876
 877  out:
 878         if (error)
 879                 kmem_cache_destroy(hugetlbfs_inode_cachep);
 880         return error;
 881 }
 882
 883 static void __exit exit_hugetlbfs_fs(void)
 884 {
 885         kmem_cache_destroy(hugetlbfs_inode_cachep);
 886         unregister_filesystem(&hugetlbfs_fs_type);
 887 }
 888
 889 module_init(init_hugetlbfs_fs)
 890 module_exit(exit_hugetlbfs_fs)
 891
 892 MODULE_LICENSE("GPL");