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