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/writeback.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/highmem.h>
  19 #include <linux/init.h>
  20 #include <linux/string.h>
  21 #include <linux/backing-dev.h>
  22 #include <linux/hugetlb.h>
  23 #include <linux/pagevec.h>
  24 #include <linux/quotaops.h>
  25 #include <linux/slab.h>
  26 #include <linux/dnotify.h>
  27 #include <linux/statfs.h>
  28 #include <linux/security.h>
  29
  30 #include <asm/uaccess.h>
  31
  32 /* some random number */
  33 #define HUGETLBFS_MAGIC 0x958458f6
  34
  35 static struct super_operations hugetlbfs_ops;
  36 static struct address_space_operations hugetlbfs_aops;
  37 struct file_operations hugetlbfs_file_operations;
  38 static struct inode_operations hugetlbfs_dir_inode_operations;
  39 static struct inode_operations hugetlbfs_inode_operations;
  40
  41 static struct backing_dev_info hugetlbfs_backing_dev_info = {
  42         .ra_pages       = 0,    /* No readahead */
  43         .memory_backed  = 1,    /* Does not contribute to dirty memory */
  44 };
  45
  46 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
  47 {
  48         struct inode *inode = file->f_dentry->d_inode;
  49         struct address_space *mapping = inode->i_mapping;
  50         loff_t len, vma_len;
  51         int ret;
  52
  53         if (vma->vm_start & ~HPAGE_MASK)
  54                 return -EINVAL;
  55
  56         if (vma->vm_end & ~HPAGE_MASK)
  57                 return -EINVAL;
  58
  59         if (vma->vm_end - vma->vm_start < HPAGE_SIZE)
  60                 return -EINVAL;
  61
  62         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
  63
  64         down(&inode->i_sem);
  65         file_accessed(file);
  66         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
  67         vma->vm_ops = &hugetlb_vm_ops;
  68         ret = hugetlb_prefault(mapping, vma);
  69         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
  70         if (ret == 0 && inode->i_size < len)
  71                 inode->i_size = len;
  72         up(&inode->i_sem);
  73
  74         return ret;
  75 }
  76
  77 /*
  78  * Called under down_write(mmap_sem), page_table_lock is not held
  79  */
  80
  81 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
  82 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
  83                 unsigned long len, unsigned long pgoff, unsigned long flags);
  84 #else
  85 static unsigned long
  86 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
  87                 unsigned long len, unsigned long pgoff, unsigned long flags)
  88 {
  89         struct mm_struct *mm = current->mm;
  90         struct vm_area_struct *vma;
  91
  92         if (len & ~HPAGE_MASK)
  93                 return -EINVAL;
  94         if (len > TASK_SIZE)
  95                 return -ENOMEM;
  96
  97         if (addr) {
  98                 addr = ALIGN(addr, HPAGE_SIZE);
  99                 vma = find_vma(mm, addr);
 100                 if (TASK_SIZE - len >= addr &&
 101                     (!vma || addr + len <= vma->vm_start))
 102                         return addr;
 103         }
 104
 105         addr = ALIGN(mm->free_area_cache, HPAGE_SIZE);
 106
 107         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 108                 /* At this point:  (!vma || addr < vma->vm_end). */
 109                 if (TASK_SIZE - len < addr)
 110                         return -ENOMEM;
 111                 if (!vma || addr + len <= vma->vm_start)
 112                         return addr;
 113                 addr = ALIGN(vma->vm_end, HPAGE_SIZE);
 114         }
 115 }
 116 #endif
 117
 118 /*
 119  * Read a page. Again trivial. If it didn't already exist
 120  * in the page cache, it is zero-filled.
 121  */
 122 static int hugetlbfs_readpage(struct file *file, struct page * page)
 123 {
 124         unlock_page(page);
 125         return -EINVAL;
 126 }
 127
 128 static int hugetlbfs_prepare_write(struct file *file,
 129                         struct page *page, unsigned offset, unsigned to)
 130 {
 131         return -EINVAL;
 132 }
 133
 134 static int hugetlbfs_commit_write(struct file *file,
 135                         struct page *page, unsigned offset, unsigned to)
 136 {
 137         return -EINVAL;
 138 }
 139
 140 void huge_pagevec_release(struct pagevec *pvec)
 141 {
 142         int i;
 143
 144         for (i = 0; i < pagevec_count(pvec); ++i)
 145                 put_page(pvec->pages[i]);
 146
 147         pagevec_reinit(pvec);
 148 }
 149
 150 void truncate_huge_page(struct page *page)
 151 {
 152         clear_page_dirty(page);
 153         ClearPageUptodate(page);
 154         remove_from_page_cache(page);
 155         put_page(page);
 156 }
 157
 158 void truncate_hugepages(struct address_space *mapping, loff_t lstart)
 159 {
 160         const pgoff_t start = lstart >> HPAGE_SHIFT;
 161         struct pagevec pvec;
 162         pgoff_t next;
 163         int i;
 164
 165         pagevec_init(&pvec, 0);
 166         next = start;
 167         while (1) {
 168                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
 169                         if (next == start)
 170                                 break;
 171                         next = start;
 172                         continue;
 173                 }
 174
 175                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 176                         struct page *page = pvec.pages[i];
 177
 178                         lock_page(page);
 179                         if (page->index > next)
 180                                 next = page->index;
 181                         ++next;
 182                         truncate_huge_page(page);
 183                         unlock_page(page);
 184                         hugetlb_put_quota(mapping);
 185                 }
 186                 huge_pagevec_release(&pvec);
 187         }
 188         BUG_ON(!lstart && mapping->nrpages);
 189 }
 190
 191 static void hugetlbfs_delete_inode(struct inode *inode)
 192 {
 193         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(inode->i_sb);
 194
 195         hlist_del_init(&inode->i_hash);
 196         list_del_init(&inode->i_list);
 197         inode->i_state |= I_FREEING;
 198         inodes_stat.nr_inodes--;
 199         spin_unlock(&inode_lock);
 200
 201         if (inode->i_data.nrpages)
 202                 truncate_hugepages(&inode->i_data, 0);
 203
 204         security_inode_delete(inode);
 205
 206         if (sbinfo->free_inodes >= 0) {
 207                 spin_lock(&sbinfo->stat_lock);
 208                 sbinfo->free_inodes++;
 209                 spin_unlock(&sbinfo->stat_lock);
 210         }
 211
 212         clear_inode(inode);
 213         destroy_inode(inode);
 214 }
 215
 216 static void hugetlbfs_forget_inode(struct inode *inode)
 217 {
 218         struct super_block *super_block = inode->i_sb;
 219         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(super_block);
 220
 221         if (hlist_unhashed(&inode->i_hash))
 222                 goto out_truncate;
 223
 224         if (!(inode->i_state & (I_DIRTY|I_LOCK))) {
 225                 list_del(&inode->i_list);
 226                 list_add(&inode->i_list, &inode_unused);
 227         }
 228         inodes_stat.nr_unused++;
 229         if (!super_block || (super_block->s_flags & MS_ACTIVE)) {
 230                 spin_unlock(&inode_lock);
 231                 return;
 232         }
 233
 234         /* write_inode_now() ? */
 235         inodes_stat.nr_unused--;
 236         hlist_del_init(&inode->i_hash);
 237 out_truncate:
 238         list_del_init(&inode->i_list);
 239         inode->i_state |= I_FREEING;
 240         inodes_stat.nr_inodes--;
 241         spin_unlock(&inode_lock);
 242         if (inode->i_data.nrpages)
 243                 truncate_hugepages(&inode->i_data, 0);
 244
 245         if (sbinfo->free_inodes >= 0) {
 246                 spin_lock(&sbinfo->stat_lock);
 247                 sbinfo->free_inodes++;
 248                 spin_unlock(&sbinfo->stat_lock);
 249         }
 250
 251         clear_inode(inode);
 252         destroy_inode(inode);
 253 }
 254
 255 static void hugetlbfs_drop_inode(struct inode *inode)
 256 {
 257         if (!inode->i_nlink)
 258                 hugetlbfs_delete_inode(inode);
 259         else
 260                 hugetlbfs_forget_inode(inode);
 261 }
 262
 263 /*
 264  * h_pgoff is in HPAGE_SIZE units.
 265  * vma->vm_pgoff is in PAGE_SIZE units.
 266  */
 267 static inline void
 268 hugetlb_vmtruncate_list(struct prio_tree_root *root, unsigned long h_pgoff)
 269 {
 270         struct vm_area_struct *vma = NULL;
 271         struct prio_tree_iter iter;
 272
 273         while ((vma = vma_prio_tree_next(vma, root, &iter,
 274                                         h_pgoff, ULONG_MAX)) != NULL) {
 275                 unsigned long h_vm_pgoff;
 276                 unsigned long v_length;
 277                 unsigned long v_offset;
 278
 279                 h_vm_pgoff = vma->vm_pgoff << (HPAGE_SHIFT - PAGE_SHIFT);
 280                 v_length = vma->vm_end - vma->vm_start;
 281                 v_offset = (h_pgoff - h_vm_pgoff) << HPAGE_SHIFT;
 282
 283                 /*
 284                  * Is this VMA fully outside the truncation point?
 285                  */
 286                 if (h_vm_pgoff >= h_pgoff)
 287                         v_offset = 0;
 288
 289                 zap_hugepage_range(vma,
 290                                 vma->vm_start + v_offset,
 291                                 v_length - v_offset);
 292         }
 293 }
 294
 295 /*
 296  * Expanding truncates are not allowed.
 297  */
 298 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 299 {
 300         unsigned long pgoff;
 301         struct address_space *mapping = inode->i_mapping;
 302
 303         if (offset > inode->i_size)
 304                 return -EINVAL;
 305
 306         BUG_ON(offset & ~HPAGE_MASK);
 307         pgoff = offset >> HPAGE_SHIFT;
 308
 309         inode->i_size = offset;
 310         spin_lock(&mapping->i_mmap_lock);
 311         if (!prio_tree_empty(&mapping->i_mmap))
 312                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 313         spin_unlock(&mapping->i_mmap_lock);
 314         truncate_hugepages(mapping, offset);
 315         return 0;
 316 }
 317
 318 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 319 {
 320         struct inode *inode = dentry->d_inode;
 321         int error;
 322         unsigned int ia_valid = attr->ia_valid;
 323
 324         BUG_ON(!inode);
 325
 326         error = inode_change_ok(inode, attr);
 327         if (error)
 328                 goto out;
 329
 330         error = security_inode_setattr(dentry, attr);
 331         if (error)
 332                 goto out;
 333         if (ia_valid & ATTR_SIZE) {
 334                 error = -EINVAL;
 335                 if (!(attr->ia_size & ~HPAGE_MASK))
 336                         error = hugetlb_vmtruncate(inode, attr->ia_size);
 337                 if (error)
 338                         goto out;
 339                 attr->ia_valid &= ~ATTR_SIZE;
 340         }
 341         error = inode_setattr(inode, attr);
 342 out:
 343         return error;
 344 }
 345
 346 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
 347                                         gid_t gid, int mode, dev_t dev)
 348 {
 349         struct inode *inode;
 350         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 351
 352         if (sbinfo->free_inodes >= 0) {
 353                 spin_lock(&sbinfo->stat_lock);
 354                 if (!sbinfo->free_inodes) {
 355                         spin_unlock(&sbinfo->stat_lock);
 356                         return NULL;
 357                 }
 358                 sbinfo->free_inodes--;
 359                 spin_unlock(&sbinfo->stat_lock);
 360         }
 361
 362         inode = new_inode(sb);
 363         if (inode) {
 364                 struct hugetlbfs_inode_info *info;
 365                 inode->i_mode = mode;
 366                 inode->i_uid = uid;
 367                 inode->i_gid = gid;
 368                 inode->i_blksize = HPAGE_SIZE;
 369                 inode->i_blocks = 0;
 370                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 371                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 372                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 373                 info = HUGETLBFS_I(inode);
 374                 mpol_shared_policy_init(&info->policy);
 375                 switch (mode & S_IFMT) {
 376                 default:
 377                         init_special_inode(inode, mode, dev);
 378                         break;
 379                 case S_IFREG:
 380                         inode->i_op = &hugetlbfs_inode_operations;
 381                         inode->i_fop = &hugetlbfs_file_operations;
 382                         break;
 383                 case S_IFDIR:
 384                         inode->i_op = &hugetlbfs_dir_inode_operations;
 385                         inode->i_fop = &simple_dir_operations;
 386
 387                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 388                         inode->i_nlink++;
 389                         break;
 390                 case S_IFLNK:
 391                         inode->i_op = &page_symlink_inode_operations;
 392                         break;
 393                 }
 394         }
 395         return inode;
 396 }
 397
 398 /*
 399  * File creation. Allocate an inode, and we're done..
 400  */
 401 static int hugetlbfs_mknod(struct inode *dir,
 402                         struct dentry *dentry, int mode, dev_t dev)
 403 {
 404         struct inode *inode;
 405         int error = -ENOSPC;
 406         gid_t gid;
 407
 408         if (dir->i_mode & S_ISGID) {
 409                 gid = dir->i_gid;
 410                 if (S_ISDIR(mode))
 411                         mode |= S_ISGID;
 412         } else {
 413                 gid = current->fsgid;
 414         }
 415         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev);
 416         if (inode) {
 417                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 418                 d_instantiate(dentry, inode);
 419                 dget(dentry);   /* Extra count - pin the dentry in core */
 420                 error = 0;
 421         }
 422         return error;
 423 }
 424
 425 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 426 {
 427         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 428         if (!retval)
 429                 dir->i_nlink++;
 430         return retval;
 431 }
 432
 433 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
 434 {
 435         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 436 }
 437
 438 static int hugetlbfs_symlink(struct inode *dir,
 439                         struct dentry *dentry, const char *symname)
 440 {
 441         struct inode *inode;
 442         int error = -ENOSPC;
 443         gid_t gid;
 444
 445         if (dir->i_mode & S_ISGID)
 446                 gid = dir->i_gid;
 447         else
 448                 gid = current->fsgid;
 449
 450         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
 451                                         gid, S_IFLNK|S_IRWXUGO, 0);
 452         if (inode) {
 453                 int l = strlen(symname)+1;
 454                 error = page_symlink(inode, symname, l);
 455                 if (!error) {
 456                         d_instantiate(dentry, inode);
 457                         dget(dentry);
 458                 } else
 459                         iput(inode);
 460         }
 461         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 462
 463         return error;
 464 }
 465
 466 /*
 467  * For direct-IO reads into hugetlb pages
 468  */
 469 int hugetlbfs_set_page_dirty(struct page *page)
 470 {
 471         return 0;
 472 }
 473
 474 static int hugetlbfs_statfs(struct super_block *sb, struct kstatfs *buf)
 475 {
 476         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 477
 478         buf->f_type = HUGETLBFS_MAGIC;
 479         buf->f_bsize = HPAGE_SIZE;
 480         if (sbinfo) {
 481                 spin_lock(&sbinfo->stat_lock);
 482                 buf->f_blocks = sbinfo->max_blocks;
 483                 buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
 484                 buf->f_files = sbinfo->max_inodes;
 485                 buf->f_ffree = sbinfo->free_inodes;
 486                 spin_unlock(&sbinfo->stat_lock);
 487         }
 488         buf->f_namelen = NAME_MAX;
 489         return 0;
 490 }
 491
 492 static void hugetlbfs_put_super(struct super_block *sb)
 493 {
 494         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 495
 496         if (sbi) {
 497                 sb->s_fs_info = NULL;
 498                 kfree(sbi);
 499         }
 500 }
 501
 502 static kmem_cache_t *hugetlbfs_inode_cachep;
 503
 504 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 505 {
 506         struct hugetlbfs_inode_info *p;
 507
 508         p = kmem_cache_alloc(hugetlbfs_inode_cachep, SLAB_KERNEL);
 509         if (!p)
 510                 return NULL;
 511         return &p->vfs_inode;
 512 }
 513
 514 static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags)
 515 {
 516         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 517
 518         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 519             SLAB_CTOR_CONSTRUCTOR)
 520                 inode_init_once(&ei->vfs_inode);
 521 }
 522
 523 static void hugetlbfs_destroy_inode(struct inode *inode)
 524 {
 525         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 526         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 527 }
 528
 529 static struct address_space_operations hugetlbfs_aops = {
 530         .readpage       = hugetlbfs_readpage,
 531         .prepare_write  = hugetlbfs_prepare_write,
 532         .commit_write   = hugetlbfs_commit_write,
 533         .set_page_dirty = hugetlbfs_set_page_dirty,
 534 };
 535
 536 struct file_operations hugetlbfs_file_operations = {
 537         .mmap                   = hugetlbfs_file_mmap,
 538         .fsync                  = simple_sync_file,
 539         .get_unmapped_area      = hugetlb_get_unmapped_area,
 540 };
 541
 542 static struct inode_operations hugetlbfs_dir_inode_operations = {
 543         .create         = hugetlbfs_create,
 544         .lookup         = simple_lookup,
 545         .link           = simple_link,
 546         .unlink         = simple_unlink,
 547         .symlink        = hugetlbfs_symlink,
 548         .mkdir          = hugetlbfs_mkdir,
 549         .rmdir          = simple_rmdir,
 550         .mknod          = hugetlbfs_mknod,
 551         .rename         = simple_rename,
 552         .setattr        = hugetlbfs_setattr,
 553 };
 554
 555 static struct inode_operations hugetlbfs_inode_operations = {
 556         .setattr        = hugetlbfs_setattr,
 557 };
 558
 559 static struct super_operations hugetlbfs_ops = {
 560         .alloc_inode    = hugetlbfs_alloc_inode,
 561         .destroy_inode  = hugetlbfs_destroy_inode,
 562         .statfs         = hugetlbfs_statfs,
 563         .drop_inode     = hugetlbfs_drop_inode,
 564         .put_super      = hugetlbfs_put_super,
 565 };
 566
 567 static int
 568 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 569 {
 570         char *opt, *value, *rest;
 571
 572         if (!options)
 573                 return 0;
 574         while ((opt = strsep(&options, ",")) != NULL) {
 575                 if (!*opt)
 576                         continue;
 577
 578                 value = strchr(opt, '=');
 579                 if (!value || !*value)
 580                         return -EINVAL;
 581                 else
 582                         *value++ = '\0';
 583
 584                 if (!strcmp(opt, "uid"))
 585                         pconfig->uid = simple_strtoul(value, &value, 0);
 586                 else if (!strcmp(opt, "gid"))
 587                         pconfig->gid = simple_strtoul(value, &value, 0);
 588                 else if (!strcmp(opt, "mode"))
 589                         pconfig->mode = simple_strtoul(value,&value,0) & 0777U;
 590                 else if (!strcmp(opt, "size")) {
 591                         unsigned long long size = memparse(value, &rest);
 592                         if (*rest == '%') {
 593                                 size <<= HPAGE_SHIFT;
 594                                 size *= max_huge_pages;
 595                                 do_div(size, 100);
 596                                 rest++;
 597                         }
 598                         size &= HPAGE_MASK;
 599                         pconfig->nr_blocks = (size >> HPAGE_SHIFT);
 600                         value = rest;
 601                 } else if (!strcmp(opt,"nr_inodes")) {
 602                         pconfig->nr_inodes = memparse(value, &rest);
 603                         value = rest;
 604                 } else
 605                         return -EINVAL;
 606
 607                 if (*value)
 608                         return -EINVAL;
 609         }
 610         return 0;
 611 }
 612
 613 static int
 614 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 615 {
 616         struct inode * inode;
 617         struct dentry * root;
 618         int ret;
 619         struct hugetlbfs_config config;
 620         struct hugetlbfs_sb_info *sbinfo;
 621
 622         config.nr_blocks = -1; /* No limit on size by default */
 623         config.nr_inodes = -1; /* No limit on number of inodes by default */
 624         config.uid = current->fsuid;
 625         config.gid = current->fsgid;
 626         config.mode = 0755;
 627         ret = hugetlbfs_parse_options(data, &config);
 628
 629         if (ret)
 630                 return ret;
 631
 632         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 633         if (!sbinfo)
 634                 return -ENOMEM;
 635         sb->s_fs_info = sbinfo;
 636         spin_lock_init(&sbinfo->stat_lock);
 637         sbinfo->max_blocks = config.nr_blocks;
 638         sbinfo->free_blocks = config.nr_blocks;
 639         sbinfo->max_inodes = config.nr_inodes;
 640         sbinfo->free_inodes = config.nr_inodes;
 641         sb->s_blocksize = HPAGE_SIZE;
 642         sb->s_blocksize_bits = HPAGE_SHIFT;
 643         sb->s_magic = HUGETLBFS_MAGIC;
 644         sb->s_op = &hugetlbfs_ops;
 645         inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
 646                                         S_IFDIR | config.mode, 0);
 647         if (!inode)
 648                 goto out_free;
 649
 650         root = d_alloc_root(inode);
 651         if (!root) {
 652                 iput(inode);
 653                 goto out_free;
 654         }
 655         sb->s_root = root;
 656         return 0;
 657 out_free:
 658         kfree(sbinfo);
 659         return -ENOMEM;
 660 }
 661
 662 int hugetlb_get_quota(struct address_space *mapping)
 663 {
 664         int ret = 0;
 665         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 666
 667         if (sbinfo->free_blocks > -1) {
 668                 spin_lock(&sbinfo->stat_lock);
 669                 if (sbinfo->free_blocks > 0)
 670                         sbinfo->free_blocks--;
 671                 else
 672                         ret = -ENOMEM;
 673                 spin_unlock(&sbinfo->stat_lock);
 674         }
 675
 676         return ret;
 677 }
 678
 679 void hugetlb_put_quota(struct address_space *mapping)
 680 {
 681         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 682
 683         if (sbinfo->free_blocks > -1) {
 684                 spin_lock(&sbinfo->stat_lock);
 685                 sbinfo->free_blocks++;
 686                 spin_unlock(&sbinfo->stat_lock);
 687         }
 688 }
 689
 690 static struct super_block *hugetlbfs_get_sb(struct file_system_type *fs_type,
 691         int flags, const char *dev_name, void *data)
 692 {
 693         return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super);
 694 }
 695
 696 static struct file_system_type hugetlbfs_fs_type = {
 697         .name           = "hugetlbfs",
 698         .get_sb         = hugetlbfs_get_sb,
 699         .kill_sb        = kill_litter_super,
 700 };
 701
 702 static struct vfsmount *hugetlbfs_vfsmount;
 703
 704 /*
 705  * Return the next identifier for a shm file
 706  */
 707 static unsigned long hugetlbfs_counter(void)
 708 {
 709         static spinlock_t lock = SPIN_LOCK_UNLOCKED;
 710         static unsigned long counter;
 711         unsigned long ret;
 712
 713         spin_lock(&lock);
 714         ret = ++counter;
 715         spin_unlock(&lock);
 716         return ret;
 717 }
 718
 719 struct file *hugetlb_zero_setup(size_t size)
 720 {
 721         int error;
 722         struct file *file;
 723         struct inode *inode;
 724         struct dentry *dentry, *root;
 725         struct qstr quick_string;
 726         char buf[16];
 727
 728         if (!can_do_mlock())
 729                 return ERR_PTR(-EPERM);
 730
 731         if (!is_hugepage_mem_enough(size))
 732                 return ERR_PTR(-ENOMEM);
 733
 734         root = hugetlbfs_vfsmount->mnt_root;
 735         snprintf(buf, 16, "%lu", hugetlbfs_counter());
 736         quick_string.name = buf;
 737         quick_string.len = strlen(quick_string.name);
 738         quick_string.hash = 0;
 739         dentry = d_alloc(root, &quick_string);
 740         if (!dentry)
 741                 return ERR_PTR(-ENOMEM);
 742
 743         error = -ENFILE;
 744         file = get_empty_filp();
 745         if (!file)
 746                 goto out_dentry;
 747
 748         error = -ENOSPC;
 749         inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
 750                                 current->fsgid, S_IFREG | S_IRWXUGO, 0);
 751         if (!inode)
 752                 goto out_file;
 753
 754         d_instantiate(dentry, inode);
 755         inode->i_size = size;
 756         inode->i_nlink = 0;
 757         file->f_vfsmnt = mntget(hugetlbfs_vfsmount);
 758         file->f_dentry = dentry;
 759         file->f_mapping = inode->i_mapping;
 760         file->f_op = &hugetlbfs_file_operations;
 761         file->f_mode = FMODE_WRITE | FMODE_READ;
 762         return file;
 763
 764 out_file:
 765         put_filp(file);
 766 out_dentry:
 767         dput(dentry);
 768         return ERR_PTR(error);
 769 }
 770
 771 static int __init init_hugetlbfs_fs(void)
 772 {
 773         int error;
 774         struct vfsmount *vfsmount;
 775
 776         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
 777                                         sizeof(struct hugetlbfs_inode_info),
 778                                         0, SLAB_RECLAIM_ACCOUNT,
 779                                         init_once, NULL);
 780         if (hugetlbfs_inode_cachep == NULL)
 781                 return -ENOMEM;
 782
 783         error = register_filesystem(&hugetlbfs_fs_type);
 784         if (error)
 785                 goto out;
 786
 787         vfsmount = kern_mount(&hugetlbfs_fs_type);
 788
 789         if (!IS_ERR(vfsmount)) {
 790                 hugetlbfs_vfsmount = vfsmount;
 791                 return 0;
 792         }
 793
 794         error = PTR_ERR(vfsmount);
 795
 796  out:
 797         if (error)
 798                 kmem_cache_destroy(hugetlbfs_inode_cachep);
 799         return error;
 800 }
 801
 802 static void __exit exit_hugetlbfs_fs(void)
 803 {
 804         kmem_cache_destroy(hugetlbfs_inode_cachep);
 805         unregister_filesystem(&hugetlbfs_fs_type);
 806 }
 807
 808 module_init(init_hugetlbfs_fs)
 809 module_exit(exit_hugetlbfs_fs)
 810
 811 MODULE_LICENSE("GPL");