SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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_prepare_write(struct file *file,
 193                         struct page *page, unsigned offset, unsigned to)
 194 {
 195         return -EINVAL;
 196 }
 197
 198 static int hugetlbfs_commit_write(struct file *file,
 199                         struct page *page, unsigned offset, unsigned to)
 200 {
 201         return -EINVAL;
 202 }
 203
 204 static void truncate_huge_page(struct page *page)
 205 {
 206         cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
 207         ClearPageUptodate(page);
 208         remove_from_page_cache(page);
 209         put_page(page);
 210 }
 211
 212 static void truncate_hugepages(struct inode *inode, loff_t lstart)
 213 {
 214         struct address_space *mapping = &inode->i_data;
 215         const pgoff_t start = lstart >> HPAGE_SHIFT;
 216         struct pagevec pvec;
 217         pgoff_t next;
 218         int i, freed = 0;
 219
 220         pagevec_init(&pvec, 0);
 221         next = start;
 222         while (1) {
 223                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
 224                         if (next == start)
 225                                 break;
 226                         next = start;
 227                         continue;
 228                 }
 229
 230                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 231                         struct page *page = pvec.pages[i];
 232
 233                         lock_page(page);
 234                         if (page->index > next)
 235                                 next = page->index;
 236                         ++next;
 237                         truncate_huge_page(page);
 238                         unlock_page(page);
 239                         hugetlb_put_quota(mapping);
 240                         freed++;
 241                 }
 242                 huge_pagevec_release(&pvec);
 243         }
 244         BUG_ON(!lstart && mapping->nrpages);
 245         hugetlb_unreserve_pages(inode, start, freed);
 246 }
 247
 248 static void hugetlbfs_delete_inode(struct inode *inode)
 249 {
 250         truncate_hugepages(inode, 0);
 251         clear_inode(inode);
 252 }
 253
 254 static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock)
 255 {
 256         struct super_block *sb = inode->i_sb;
 257
 258         if (!hlist_unhashed(&inode->i_hash)) {
 259                 if (!(inode->i_state & (I_DIRTY|I_LOCK)))
 260                         list_move(&inode->i_list, &inode_unused);
 261                 inodes_stat.nr_unused++;
 262                 if (!sb || (sb->s_flags & MS_ACTIVE)) {
 263                         spin_unlock(&inode_lock);
 264                         return;
 265                 }
 266                 inode->i_state |= I_WILL_FREE;
 267                 spin_unlock(&inode_lock);
 268                 /*
 269                  * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
 270                  * in our backing_dev_info.
 271                  */
 272                 write_inode_now(inode, 1);
 273                 spin_lock(&inode_lock);
 274                 inode->i_state &= ~I_WILL_FREE;
 275                 inodes_stat.nr_unused--;
 276                 hlist_del_init(&inode->i_hash);
 277         }
 278         list_del_init(&inode->i_list);
 279         list_del_init(&inode->i_sb_list);
 280         inode->i_state |= I_FREEING;
 281         inodes_stat.nr_inodes--;
 282         spin_unlock(&inode_lock);
 283         truncate_hugepages(inode, 0);
 284         clear_inode(inode);
 285         destroy_inode(inode);
 286 }
 287
 288 static void hugetlbfs_drop_inode(struct inode *inode)
 289 {
 290         if (!inode->i_nlink)
 291                 generic_delete_inode(inode);
 292         else
 293                 hugetlbfs_forget_inode(inode);
 294 }
 295
 296 static inline void
 297 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
 298 {
 299         struct vm_area_struct *vma;
 300         struct prio_tree_iter iter;
 301
 302         vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
 303                 unsigned long v_offset;
 304
 305                 /*
 306                  * Can the expression below overflow on 32-bit arches?
 307                  * No, because the prio_tree returns us only those vmas
 308                  * which overlap the truncated area starting at pgoff,
 309                  * and no vma on a 32-bit arch can span beyond the 4GB.
 310                  */
 311                 if (vma->vm_pgoff < pgoff)
 312                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
 313                 else
 314                         v_offset = 0;
 315
 316                 __unmap_hugepage_range(vma,
 317                                 vma->vm_start + v_offset, vma->vm_end);
 318         }
 319 }
 320
 321 /*
 322  * Expanding truncates are not allowed.
 323  */
 324 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 325 {
 326         pgoff_t pgoff;
 327         struct address_space *mapping = inode->i_mapping;
 328
 329         if (offset > inode->i_size)
 330                 return -EINVAL;
 331
 332         BUG_ON(offset & ~HPAGE_MASK);
 333         pgoff = offset >> PAGE_SHIFT;
 334
 335         inode->i_size = offset;
 336         spin_lock(&mapping->i_mmap_lock);
 337         if (!prio_tree_empty(&mapping->i_mmap))
 338                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 339         spin_unlock(&mapping->i_mmap_lock);
 340         truncate_hugepages(inode, offset);
 341         return 0;
 342 }
 343
 344 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 345 {
 346         struct inode *inode = dentry->d_inode;
 347         int error;
 348         unsigned int ia_valid = attr->ia_valid;
 349
 350         BUG_ON(!inode);
 351
 352         error = inode_change_ok(inode, attr);
 353         if (error)
 354                 goto out;
 355
 356         if (ia_valid & ATTR_SIZE) {
 357                 error = -EINVAL;
 358                 if (!(attr->ia_size & ~HPAGE_MASK))
 359                         error = hugetlb_vmtruncate(inode, attr->ia_size);
 360                 if (error)
 361                         goto out;
 362                 attr->ia_valid &= ~ATTR_SIZE;
 363         }
 364         error = inode_setattr(inode, attr);
 365 out:
 366         return error;
 367 }
 368
 369 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
 370                                         gid_t gid, int mode, dev_t dev)
 371 {
 372         struct inode *inode;
 373
 374         inode = new_inode(sb);
 375         if (inode) {
 376                 struct hugetlbfs_inode_info *info;
 377                 inode->i_mode = mode;
 378                 inode->i_uid = uid;
 379                 inode->i_gid = gid;
 380                 inode->i_blocks = 0;
 381                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 382                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 383                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 384                 INIT_LIST_HEAD(&inode->i_mapping->private_list);
 385                 info = HUGETLBFS_I(inode);
 386                 mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, NULL);
 387                 switch (mode & S_IFMT) {
 388                 default:
 389                         init_special_inode(inode, mode, dev);
 390                         break;
 391                 case S_IFREG:
 392                         inode->i_op = &hugetlbfs_inode_operations;
 393                         inode->i_fop = &hugetlbfs_file_operations;
 394                         break;
 395                 case S_IFDIR:
 396                         inode->i_op = &hugetlbfs_dir_inode_operations;
 397                         inode->i_fop = &simple_dir_operations;
 398
 399                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 400                         inc_nlink(inode);
 401                         break;
 402                 case S_IFLNK:
 403                         inode->i_op = &page_symlink_inode_operations;
 404                         break;
 405                 }
 406         }
 407         return inode;
 408 }
 409
 410 /*
 411  * File creation. Allocate an inode, and we're done..
 412  */
 413 static int hugetlbfs_mknod(struct inode *dir,
 414                         struct dentry *dentry, int mode, dev_t dev)
 415 {
 416         struct inode *inode;
 417         int error = -ENOSPC;
 418         gid_t gid;
 419
 420         if (dir->i_mode & S_ISGID) {
 421                 gid = dir->i_gid;
 422                 if (S_ISDIR(mode))
 423                         mode |= S_ISGID;
 424         } else {
 425                 gid = current->fsgid;
 426         }
 427         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev);
 428         if (inode) {
 429                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 430                 d_instantiate(dentry, inode);
 431                 dget(dentry);   /* Extra count - pin the dentry in core */
 432                 error = 0;
 433         }
 434         return error;
 435 }
 436
 437 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 438 {
 439         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 440         if (!retval)
 441                 inc_nlink(dir);
 442         return retval;
 443 }
 444
 445 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
 446 {
 447         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 448 }
 449
 450 static int hugetlbfs_symlink(struct inode *dir,
 451                         struct dentry *dentry, const char *symname)
 452 {
 453         struct inode *inode;
 454         int error = -ENOSPC;
 455         gid_t gid;
 456
 457         if (dir->i_mode & S_ISGID)
 458                 gid = dir->i_gid;
 459         else
 460                 gid = current->fsgid;
 461
 462         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
 463                                         gid, S_IFLNK|S_IRWXUGO, 0);
 464         if (inode) {
 465                 int l = strlen(symname)+1;
 466                 error = page_symlink(inode, symname, l);
 467                 if (!error) {
 468                         d_instantiate(dentry, inode);
 469                         dget(dentry);
 470                 } else
 471                         iput(inode);
 472         }
 473         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 474
 475         return error;
 476 }
 477
 478 /*
 479  * mark the head page dirty
 480  */
 481 static int hugetlbfs_set_page_dirty(struct page *page)
 482 {
 483         struct page *head = compound_head(page);
 484
 485         SetPageDirty(head);
 486         return 0;
 487 }
 488
 489 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 490 {
 491         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
 492
 493         buf->f_type = HUGETLBFS_MAGIC;
 494         buf->f_bsize = HPAGE_SIZE;
 495         if (sbinfo) {
 496                 spin_lock(&sbinfo->stat_lock);
 497                 /* If no limits set, just report 0 for max/free/used
 498                  * blocks, like simple_statfs() */
 499                 if (sbinfo->max_blocks >= 0) {
 500                         buf->f_blocks = sbinfo->max_blocks;
 501                         buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
 502                         buf->f_files = sbinfo->max_inodes;
 503                         buf->f_ffree = sbinfo->free_inodes;
 504                 }
 505                 spin_unlock(&sbinfo->stat_lock);
 506         }
 507         buf->f_namelen = NAME_MAX;
 508         return 0;
 509 }
 510
 511 static void hugetlbfs_put_super(struct super_block *sb)
 512 {
 513         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 514
 515         if (sbi) {
 516                 sb->s_fs_info = NULL;
 517                 kfree(sbi);
 518         }
 519 }
 520
 521 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 522 {
 523         if (sbinfo->free_inodes >= 0) {
 524                 spin_lock(&sbinfo->stat_lock);
 525                 if (unlikely(!sbinfo->free_inodes)) {
 526                         spin_unlock(&sbinfo->stat_lock);
 527                         return 0;
 528                 }
 529                 sbinfo->free_inodes--;
 530                 spin_unlock(&sbinfo->stat_lock);
 531         }
 532
 533         return 1;
 534 }
 535
 536 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 537 {
 538         if (sbinfo->free_inodes >= 0) {
 539                 spin_lock(&sbinfo->stat_lock);
 540                 sbinfo->free_inodes++;
 541                 spin_unlock(&sbinfo->stat_lock);
 542         }
 543 }
 544
 545
 546 static struct kmem_cache *hugetlbfs_inode_cachep;
 547
 548 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 549 {
 550         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 551         struct hugetlbfs_inode_info *p;
 552
 553         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 554                 return NULL;
 555         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
 556         if (unlikely(!p)) {
 557                 hugetlbfs_inc_free_inodes(sbinfo);
 558                 return NULL;
 559         }
 560         return &p->vfs_inode;
 561 }
 562
 563 static void hugetlbfs_destroy_inode(struct inode *inode)
 564 {
 565         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 566         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 567         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 568 }
 569
 570 static const struct address_space_operations hugetlbfs_aops = {
 571         .readpage       = hugetlbfs_readpage,
 572         .prepare_write  = hugetlbfs_prepare_write,
 573         .commit_write   = hugetlbfs_commit_write,
 574         .set_page_dirty = hugetlbfs_set_page_dirty,
 575 };
 576
 577
 578 static void init_once(void *foo, struct kmem_cache *cachep, unsigned long flags)
 579 {
 580         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 581
 582         inode_init_once(&ei->vfs_inode);
 583 }
 584
 585 const struct file_operations hugetlbfs_file_operations = {
 586         .mmap                   = hugetlbfs_file_mmap,
 587         .fsync                  = simple_sync_file,
 588         .get_unmapped_area      = hugetlb_get_unmapped_area,
 589 };
 590
 591 static const struct inode_operations hugetlbfs_dir_inode_operations = {
 592         .create         = hugetlbfs_create,
 593         .lookup         = simple_lookup,
 594         .link           = simple_link,
 595         .unlink         = simple_unlink,
 596         .symlink        = hugetlbfs_symlink,
 597         .mkdir          = hugetlbfs_mkdir,
 598         .rmdir          = simple_rmdir,
 599         .mknod          = hugetlbfs_mknod,
 600         .rename         = simple_rename,
 601         .setattr        = hugetlbfs_setattr,
 602 };
 603
 604 static const struct inode_operations hugetlbfs_inode_operations = {
 605         .setattr        = hugetlbfs_setattr,
 606 };
 607
 608 static const struct super_operations hugetlbfs_ops = {
 609         .alloc_inode    = hugetlbfs_alloc_inode,
 610         .destroy_inode  = hugetlbfs_destroy_inode,
 611         .statfs         = hugetlbfs_statfs,
 612         .delete_inode   = hugetlbfs_delete_inode,
 613         .drop_inode     = hugetlbfs_drop_inode,
 614         .put_super      = hugetlbfs_put_super,
 615 };
 616
 617 static int
 618 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 619 {
 620         char *p, *rest;
 621         substring_t args[MAX_OPT_ARGS];
 622         int option;
 623
 624         if (!options)
 625                 return 0;
 626
 627         while ((p = strsep(&options, ",")) != NULL) {
 628                 int token;
 629                 if (!*p)
 630                         continue;
 631
 632                 token = match_token(p, tokens, args);
 633                 switch (token) {
 634                 case Opt_uid:
 635                         if (match_int(&args[0], &option))
 636                                 goto bad_val;
 637                         pconfig->uid = option;
 638                         break;
 639
 640                 case Opt_gid:
 641                         if (match_int(&args[0], &option))
 642                                 goto bad_val;
 643                         pconfig->gid = option;
 644                         break;
 645
 646                 case Opt_mode:
 647                         if (match_octal(&args[0], &option))
 648                                 goto bad_val;
 649                         pconfig->mode = option & 0777U;
 650                         break;
 651
 652                 case Opt_size: {
 653                         unsigned long long size;
 654                         /* memparse() will accept a K/M/G without a digit */
 655                         if (!isdigit(*args[0].from))
 656                                 goto bad_val;
 657                         size = memparse(args[0].from, &rest);
 658                         if (*rest == '%') {
 659                                 size <<= HPAGE_SHIFT;
 660                                 size *= max_huge_pages;
 661                                 do_div(size, 100);
 662                         }
 663                         pconfig->nr_blocks = (size >> HPAGE_SHIFT);
 664                         break;
 665                 }
 666
 667                 case Opt_nr_inodes:
 668                         /* memparse() will accept a K/M/G without a digit */
 669                         if (!isdigit(*args[0].from))
 670                                 goto bad_val;
 671                         pconfig->nr_inodes = memparse(args[0].from, &rest);
 672                         break;
 673
 674                 default:
 675                         printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
 676                                  p);
 677                         return -EINVAL;
 678                         break;
 679                 }
 680         }
 681         return 0;
 682
 683 bad_val:
 684         printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
 685                args[0].from, p);
 686         return 1;
 687 }
 688
 689 static int
 690 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 691 {
 692         struct inode * inode;
 693         struct dentry * root;
 694         int ret;
 695         struct hugetlbfs_config config;
 696         struct hugetlbfs_sb_info *sbinfo;
 697
 698         config.nr_blocks = -1; /* No limit on size by default */
 699         config.nr_inodes = -1; /* No limit on number of inodes by default */
 700         config.uid = current->fsuid;
 701         config.gid = current->fsgid;
 702         config.mode = 0755;
 703         ret = hugetlbfs_parse_options(data, &config);
 704         if (ret)
 705                 return ret;
 706
 707         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 708         if (!sbinfo)
 709                 return -ENOMEM;
 710         sb->s_fs_info = sbinfo;
 711         spin_lock_init(&sbinfo->stat_lock);
 712         sbinfo->max_blocks = config.nr_blocks;
 713         sbinfo->free_blocks = config.nr_blocks;
 714         sbinfo->max_inodes = config.nr_inodes;
 715         sbinfo->free_inodes = config.nr_inodes;
 716         sb->s_maxbytes = MAX_LFS_FILESIZE;
 717         sb->s_blocksize = HPAGE_SIZE;
 718         sb->s_blocksize_bits = HPAGE_SHIFT;
 719         sb->s_magic = HUGETLBFS_MAGIC;
 720         sb->s_op = &hugetlbfs_ops;
 721         sb->s_time_gran = 1;
 722         inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
 723                                         S_IFDIR | config.mode, 0);
 724         if (!inode)
 725                 goto out_free;
 726
 727         root = d_alloc_root(inode);
 728         if (!root) {
 729                 iput(inode);
 730                 goto out_free;
 731         }
 732         sb->s_root = root;
 733         return 0;
 734 out_free:
 735         kfree(sbinfo);
 736         return -ENOMEM;
 737 }
 738
 739 int hugetlb_get_quota(struct address_space *mapping)
 740 {
 741         int ret = 0;
 742         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 743
 744         if (sbinfo->free_blocks > -1) {
 745                 spin_lock(&sbinfo->stat_lock);
 746                 if (sbinfo->free_blocks > 0)
 747                         sbinfo->free_blocks--;
 748                 else
 749                         ret = -ENOMEM;
 750                 spin_unlock(&sbinfo->stat_lock);
 751         }
 752
 753         return ret;
 754 }
 755
 756 void hugetlb_put_quota(struct address_space *mapping)
 757 {
 758         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 759
 760         if (sbinfo->free_blocks > -1) {
 761                 spin_lock(&sbinfo->stat_lock);
 762                 sbinfo->free_blocks++;
 763                 spin_unlock(&sbinfo->stat_lock);
 764         }
 765 }
 766
 767 static int hugetlbfs_get_sb(struct file_system_type *fs_type,
 768         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 769 {
 770         return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super, mnt);
 771 }
 772
 773 static struct file_system_type hugetlbfs_fs_type = {
 774         .name           = "hugetlbfs",
 775         .get_sb         = hugetlbfs_get_sb,
 776         .kill_sb        = kill_litter_super,
 777 };
 778
 779 static struct vfsmount *hugetlbfs_vfsmount;
 780
 781 static int can_do_hugetlb_shm(void)
 782 {
 783         return likely(capable(CAP_IPC_LOCK) ||
 784                         in_group_p(sysctl_hugetlb_shm_group) ||
 785                         can_do_mlock());
 786 }
 787
 788 struct file *hugetlb_file_setup(const char *name, size_t size)
 789 {
 790         int error = -ENOMEM;
 791         struct file *file;
 792         struct inode *inode;
 793         struct dentry *dentry, *root;
 794         struct qstr quick_string;
 795
 796         if (!hugetlbfs_vfsmount)
 797                 return ERR_PTR(-ENOENT);
 798
 799         if (!can_do_hugetlb_shm())
 800                 return ERR_PTR(-EPERM);
 801
 802         if (!user_shm_lock(size, current->user))
 803                 return ERR_PTR(-ENOMEM);
 804
 805         root = hugetlbfs_vfsmount->mnt_root;
 806         quick_string.name = name;
 807         quick_string.len = strlen(quick_string.name);
 808         quick_string.hash = 0;
 809         dentry = d_alloc(root, &quick_string);
 810         if (!dentry)
 811                 goto out_shm_unlock;
 812
 813         error = -ENFILE;
 814         file = get_empty_filp();
 815         if (!file)
 816                 goto out_dentry;
 817
 818         error = -ENOSPC;
 819         inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
 820                                 current->fsgid, S_IFREG | S_IRWXUGO, 0);
 821         if (!inode)
 822                 goto out_file;
 823
 824         error = -ENOMEM;
 825         if (hugetlb_reserve_pages(inode, 0, size >> HPAGE_SHIFT))
 826                 goto out_inode;
 827
 828         d_instantiate(dentry, inode);
 829         inode->i_size = size;
 830         inode->i_nlink = 0;
 831         file->f_path.mnt = mntget(hugetlbfs_vfsmount);
 832         file->f_path.dentry = dentry;
 833         file->f_mapping = inode->i_mapping;
 834         file->f_op = &hugetlbfs_file_operations;
 835         file->f_mode = FMODE_WRITE | FMODE_READ;
 836         return file;
 837
 838 out_inode:
 839         iput(inode);
 840 out_file:
 841         put_filp(file);
 842 out_dentry:
 843         dput(dentry);
 844 out_shm_unlock:
 845         user_shm_unlock(size, current->user);
 846         return ERR_PTR(error);
 847 }
 848
 849 static int __init init_hugetlbfs_fs(void)
 850 {
 851         int error;
 852         struct vfsmount *vfsmount;
 853
 854         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
 855                                         sizeof(struct hugetlbfs_inode_info),
 856                                         0, 0, init_once);
 857         if (hugetlbfs_inode_cachep == NULL)
 858                 return -ENOMEM;
 859
 860         error = register_filesystem(&hugetlbfs_fs_type);
 861         if (error)
 862                 goto out;
 863
 864         vfsmount = kern_mount(&hugetlbfs_fs_type);
 865
 866         if (!IS_ERR(vfsmount)) {
 867                 hugetlbfs_vfsmount = vfsmount;
 868                 return 0;
 869         }
 870
 871         error = PTR_ERR(vfsmount);
 872
 873  out:
 874         if (error)
 875                 kmem_cache_destroy(hugetlbfs_inode_cachep);
 876         return error;
 877 }
 878
 879 static void __exit exit_hugetlbfs_fs(void)
 880 {
 881         kmem_cache_destroy(hugetlbfs_inode_cachep);
 882         unregister_filesystem(&hugetlbfs_fs_type);
 883 }
 884
 885 module_init(init_hugetlbfs_fs)
 886 module_exit(exit_hugetlbfs_fs)
 887
 888 MODULE_LICENSE("GPL");